US3583017A

US3583017A - Floor polishing and scrubbing machine

Info

Publication number: US3583017A
Application number: US756840A
Authority: US
Inventors: Robert T Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-09-03
Filing date: 1968-09-03
Publication date: 1971-06-08
Anticipated expiration: 1988-06-08

Abstract

IN ADDITION TO THE CONVENTIONAL FLOOR SCRUBBING BRUSH OR PAD, A SMALLER PRESSURE ELEMENT IS PROVIDED TO EXERT LOCALIZED CONCENTRATED PRESSURE. SUCH CONCENTRATED PRESSURE ELEMENT MAY BE A SMALL RESSURE HEAD LOCATED TO BE PRESSED DOWNWARD BY A RECIPROCABLE ROD EXTENDING THROUGH THE HOLLOW MOTOR SHAFT OR THROUGH THE HOLLOW CENTER OF AN ANNULAR BRUSH. ALTERNATIVELY, SUCH CONCENTRATED PRESSURE ELEMENT CAN BE AN ANNULAR RING SPACED FROM THE BRUSH CENTER. THE RING OR HEAD CAN ENGAGE A FLEXIBLE DIAPHRAGM WHICH CAN PRESS A PAD AGAINST THE FLOOD. THE CONCENTRATED PRESSURE ELEMENT CAN BE DRIVEN TO ROTATE WITH THE CONVENTIONAL BRUSH OR INDEPENDENTLY OF IT. ALSO, THE CONCENTRATED PRESSURE ELEMENT CAN BE MOUNTED FROM THE POILISHING AND SCRUBBING MACHINE BODY INDEPENDENTLY OF THE CONVENTIONAL BRUSH OR IT CAN BE MOUNTED ON AND REMOVABLE WITH THE BRUSH. A BOWDEN WIRE, A FLUID JACK, AN INCLINED WEDGE, THRUST LINKAGE OR AN INFLATABLE PRESSURE MEMBER CAN EFFECT DOWNWARD PROJECTION OF THE CONCENTRATED PRESSURE ELEMENT. LIQUID WAX OR SOAP CAN BE DISPENSED BY MANUAL CONTROL FROM A RESERVOIR CARRIED BY THE HANDLE THROUGH A DUCT TO THE FLOOR-ENGAGING BRUSH OR PAD.

Description

June 8, 1971 R. 'r. DAVIS FLOOR POLISHING AND SCRUBBING MACHINE 7 Sheets-Sheet 1 Filed Sept. 3. 1968 3 AMI, m 2

I may? I %AV% 5 /2 35 5 4 2 BY a, ,f4 ,-@I K Arrows 5r June 8, 197-] R. T. DAVIS FLOOR POLISHING AND SCRUBB ING MACHINE 7 Sheets-Sheet z Filed Sept. 5. k68

June 8,1971 R. T. DAVIS moon rousnme AND scnusame MACHINE 7 Sheets-Sheet 5 Filed Sept. 5. 1968 June 8, 1971 R. T. DAVIS 3,583,011

FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5. 1968 7 Sheets-Sheet 27 a 52 ll I 'IIIIIIIIIIIIIIIA o l I I 6 I Be -4&7 Z 2 Hal.

INVIV'IN'IUR, @9866) 77 DAV/5 June 8,, 1971 DAVls 3,583,017

FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5. 1968 TSheets-Sheet s Mme 8, 1971 R. "r. DAVIS 3,583,017

FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5, 1968 7 Sheets-Sheet 6 w M 1 a

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BY M -M A rrOuPA/EV R. T. DAVIS FLOOR POLISHING AND SCRUBBING MACHINE Filed Sept. 5, 1968 7 Sheets-Sheet '7 NVIZ Roaeer .7:

United States Patent Oifice 3,583,017 Patented June 8, 1971 3,583,017 FLOOR POLISHING AND SCRUBBING MACHINE U.S. CI. -98 11 Claims ABSTRACT OF THE DISCLOSURE In addition to the conventional floor scrubbing brush or pad, a smaller pressure element is provided to exert localized concentrated pressure. Such concentrated pressure element may be a small pressure head located to be pressed downward by a reciprocable rod extending through the hollow motor shaft or through the hollow center of an annular brush. Alternatively, such concentrated pressure element can be an annular ring spaced from the brush center. The ring or head can engage a flexible diaphragm which can press a pad against the floor. The concentrated pressure element can be driven to rotate with the conventional brush or independently of it. Also, the concentrated pressure element can be mounted from the polishing and scrubbing machine body independently of the conventional brush or it can be mounted on and removable with the brush. A Bowden wire, a fluid jack, an inclined wedge, thrust linkage or an inflatable pressure member can effect downward projection of the concentrated pressure element. Liquid wax or soap can be dispensed by manual control from a reservoir carried by the handle through a duct to the floor-engaging brush or pad.

This application is a continuation-in-part of application Ser. No. 546,712, filed May 2, 1966 for Floor Polishing and Scrubbing Machine, now abandoned. This invention relates to a machine for polishing and scrubbing floors such as for polishing wax on hardwood floors or floors of asphalt tile or scrubbing floors of asphalt tile or carpets, for example. The machine in general is of conventional type, including a casing supporting a motor in a position with its axis upright and an annular brush received in a recess in the lower portion of the casing which is driven rotatively by the motor.

The principal object of the present invention is to enable such a floor polishing and scrubbing machine to be used more effectively and easily by applying liquid wax or detergent within the hollow central portion of the annular brush so that it will be trapped against escaping without being operated on by the brush.

An additional object is to enable concentrated cleaning pressure to be exerted on a small area within the annulus of the usual brush and to enable such pressure to be controlled both as to duration and degree at the will of the operator.

It is also an object to provide not only concentrated pressure when desired, but also pressure of a surfacecontacting element which can be rotated rapidly in contact with a floor surface while such pressure is exerted on it.

Despite the provision of an element for applying concentrated local pressure it is an object to enable liquid detergent or wax to be supplied within the hollow of an annular floor polishing and scrubbing machine brush and possibly onto the element which exerts the concentrated local pressure on the floor surface.

A further object is to provide a concentrated pressure element which is carried by a removable brush so that a conventional floor polishing and scrubbing machine could be converted readily principally by substituting a different removable brush and making minor modifications in the body of the machine.

These objects can be achieved by modifying the structure of a conventional floor polishing and scrubbing machine of the type described above in providing a hollow motor drive shaft through which liquid wax or detergent can be supplied to the hollow in the center of the brush, or which will receive a rod which can be pressed lengthwise downward to exert pressure on a pres sure head located within the annulus of the brush. Such pressure rod can be hollow to enable liquid detergent or Wax to be supplied through such pressure rod onto the concentrated pressure element. In addition, an auxiliary motor can be connected to the upper end of the pressure rod for rotating it. In such case, a pressure head independent of the conventional annular brush is mounted on the lower end of the pressure rod so that it can be rotated at a speed higher than the conventional brush while downward pressure is being exerted on the pressure rod. Controls for exerting downward pressure on the rod for dispensing liquid detergent or Wax and for controlling the energization of the auxiliary pressure rod rotating motor can be mounted on the handle customarily provided on a floor polishing and scrubbing machine for manipulating it. Alternatively, the concentrated pressure element can be built into a removable brush head so that such element can be provided as a feature of a removable brush and actuating means for such element can be applied to the body with minimum modification of the machine body. Such construction is of a type which will enable a conventional fioor polishing machine to be converted into a machine equipped with the present invention.

FIG. 1 is a top perspective of a fioor polishing and scrubbing machine incorporating the present invention. FIG. 2 is an enlarged side elevation of such machine with parts broken away and showing parts in retracted position, and FIG. 3 is a similar view with additional parts broken away and showing parts in projected operative position. FIG. 4 is a fragmentary top perspective of the upper portion of the machine.

FIG. 5 is a top perspective of the upper portion of the machine similar to FIG. 4 but showing a somewhat modified construction.

FIG. 6 is a top perspective of another form of the floor polishing and scrubbing machine, and FIG. 7 is a side elevation of such machine on an enlarged scale with parts broken away.

FIG. 8 is a top perspective of still another form of the machine, and FIG. 9 is a side elevation of such machine on an enlarged scale with parts broken away.

FIGS. 10, 11, '12 and 13 are side elevations with parts broken away of diiferent types of floor polishing machines in which the invention has been incorporated to provide a central concentrated pressure element.

FIG. 14 is a fragmentary vertical section through the lower portion of a floor polishing and scrubbing machine equipped with a different type of brush and concentrated pressure structure.

FIG. 15 is a side elevation of a floor polishing and scrubbing machine having a movable brush carrying a concentrated pressure element and FIG. 16 is a horizontal section through such machine taken on line 16-16 of FIG. '15. FIG. 17 is a detailed vertical section through a portion of the brush mechanism of such machine taken along line 17-17 of FIG. 15.

FIG. 18 is a side elevation with parts broken away corresponding to FIG. 15 but with parts shown in a different relationship and FIG. 19 is a detailed vertical section corresponding to FIG. 17 but with parts shown in the different relationship of FIG. 18, such view being taken along line 1919 of FIG. 18.

FIG. 20 is a bottom perspective of a component of the machine shown in FIGS. 15, 16 and 18.

FIG. 21 is a fragmentary vertical section through a portion of a floor polishing and scrubbing machine having a structure somewhat similar to that of the machine shown in FIGS. 15, 16 and 18, but of modified type.

FIG. 22 is a side elevation with parts broken away of a floor polishing and scrubbing machine having another type of concentrated pressure element incorporated in a removable polishing and scrubbing head. FIGS. 23 and 24 are fragmentary vertical sections through a portion of the polishing and scrubbing head showing parts in different relative positions. FIG. 25 is a top perspective of the structure shown in FIGS. 23 and 24 with parts broken away. FIG. 26 is a vertical section taken on line 2626 of FIG. 24.

FIGS. 27 and 28 are fragmentary vertical sections corresponding respectively to FIGS. 23 and 24 but showing a different type of actuating mechanism for a concentrated pressure element. FIG. 29 is a detail top perspective of a portion of the structure shown in FIGS. 27 and 28.

FIGS. 30, 31 and 32 are detail vertical sections through a portion of a floor polishing and scrubbing machine gen erally of the type shown in FIG. 22 but embodying a different type of concentrated pressure element and actuating mechanism, the several figures showing different components of the mechanism.

FIGS. 33 and 34 are vertical sections through the central portions of floor polishing and scrubbing machines showing floor polishing and scrubbing machine structures for dispensing liquid which differ somewhat from each other and which differ considerably from the types of machine illustrated in the preceding figures. FIG. 35 is a fragmentary vertical section taken on line 35-35 of FIG. 34.

FIGS. 36 and 37 are vertical sections through floor polishing and scrubbing machines generally like those shown in FIGS. 33 and 34 but having somewhat different structures and structures which differ to some extent from each other.

FIG. 38 is a vertical section through a portion of a floor polishing and scrubbing machine of a different type constructed both to apply concentrated pressure and to dispense liquid, and FIG. 39 is an enlarged similar section of a smaller portion of the machine with parts in a different relationship.

A conventional floor polishing and scrubbing machine to which the present invention may be applied includes a casing 1 encircling an annular brush 2 which is received in a downwardly opening recess 3 of the casing. Such brush is removable, being secured by a disengageable brush-attaching coupling 4 to a brush-rotating driving head within the casing. Such casing supports an electric motor 6 in a position with its rotative axis upright and concentric with the brush 2. Such motor is connected to the brush through speed-reducing planetary gearing 7 by which the driving head 5 is rotated at a speed considerably less than the rotative speed of the motor.

The floor polishing and scrubbing machine is guided manually for movement over the floor by a handle 8 inclined upwardly from the casing 1 and having transverse handle grips 9 on its upper end. The machine can be supported by retractable wheels when in the lowered position to enable the machine to be wheeled from place to place with little or no contact of the brush 2 with the floor. When the machine is in use for polishing or scrubbing purposes, however, the wheels 10 will be swung upward so that the machine rests on the brush 2 as shown in FIG. 2. In such event the weight of the machine assists the polishing or scrubbing action of the brush.

The polishing or scrubbing action of brush 2 is accomplished primarily by movement of the brush over the surface to be cleaned or polished. Such movement of the brush is in proportion to the circumferential speed of the brush and, consequently, portions of the brush farther from the axis of rotation of the motor 6 move faster than portions closer to such axis. It is principally to attain higher speed of the brush 2 relative to the floor that the brush is of annular shape rather than being a complete disk.

In addition to the speed of a brush section relative to a surface to be polished or scrubbed, the pressure of the brush on the floor is an important factor influencing the effectiveness of the polishing or scrubbing action. The pressure exerted on the floor by any selected section of the brush is determined by the Weight of the machine and the total area of the brush 2 over which that weight is distributed. There is, of course, a practical limit to the weight of the machine if it is to be capable of being carried manually with reasonable effort. If the brush 2 is made sufficiently small to exert a high unit area pressure, the surface of the floor being operated on could become undesirably small. For general purposes, therefore, a more effective polishing and scrubbing action is obtained by the use of an annular brush having a hollow central portion, which is conventional. Not only is the effective speed of movement of such a brush over the floor higher for a given speed of rotation of the motor 6, but the actual difference in speed between inner and outer portions of the brush is less. It would not be practical to set the speed of brush rotation to obtain an adequate linear speed for the center of a disk-type brush because the linear speed of the peripheral portions of the brush would then he greater than desirable.

While it is desirable to provide a reasonably great area of contact between the brush face and the floor for general polishing and scrubbing operations, it is desirable under some conditions to be able to apply a concentrated cleaning or polishing action on a local portion of the floor surface. Such concentrated scrubbing or polishing action would be advantageous where there is a black mark on a hardwood floor, for example, or a stain spot on a carpet. A conventional floor polishing or scrubbing machine cannot be utilized effectively to exert a concentrated polishing or scrubbing action on such local blemishes. It is not very practical to provide a special machine for this purpose because in most cases it would be necessary for an operator to use first one machine and then another in polishing or scrubbing a particular floor.

As has been mentioned above, the two principal factors in governing the effectiveness of a polishing or scrubbing operation are the linear speed of movement of the polishing element and the pressure of such element. Also, it is possible to vary at least the scrubbing effectiveness of an element by varying the material used for it. Thus, if the element is made of more abrasive material, it will have an increased scrubbing effect. By utilization of the present invention concentrated pressure for increased localized polishing or scrubbing action can be obtained voluntarily for any desired period by providing a modification for the floor polishing and scrubbing machine, and, in producing such concentrated local scrubbing, the pressure can be increased, or the speed of movement of the 'scrubbing element can also be increased, and different types of scrubbing elements can be utilized at will.

In FIGS. 2 and 3, a local surface-contacting scrubbing element 11 is shown received in the hollow center of the conventional annular brush 2. In this instance such surface contacting element is a pad of steel wool. Backing this pressure pad is a flexible diaphragm 12 mounted in and closing the hollow center of the annular brush 2. To facilitate deflection of such diaphragm, the marginal portion preferably is of relatively thin material and the central portion is of relatively thick material so as to be able to withstand pressure and wear more readily. Such diaphragm can be made of any suitable flexible material such as soft rubber or plastic. The marginal portion of this diaphragm is secured firmly to the inner periphery of the brush 2 so that the diaphragm will be turned as the brush rotates.

The diaphragm 12 is made of material sufficiently limp so that by itself it will not apply any appreciable pressure to the surface-contacting pad 11. Also, in relaxed condition the diaphragm will not effect positive rotation of the polishing or abrading pad 11 because it is preferred that such pad not be secured to the diaphragm in any way, but that it simply be placed loosely in the central hollow of the annular brush 2.

If pressure is applied to the upper side of the diaphragm 12, its central portion will be deflected downwardly to press firmly against the abrasive pressure pad 11 so that its pressure against the floor surface will be increased and the rotation of the diaphragm 12 will be transmitted to such pressure pad. Means for thus deflecting the diaphragm downward includes the pressure head or disk 13 located above the central portion of the diaphragm, which preferably has a convex lower side and is rotatively mounted on the lower end of pressure rod 14 extending upward through the hollow drive shaft 15 of the motor 6. Such drive shaft is mounted for rotation relative to the machine casing by an upper antifriction bearing 16 and a lower antifriction bearing 17. The upper end of the space between the pressure rod 14 and the hollow motor drive shaft 15 is sealed by the upper seal 16' and the lower end by seal 17'.

When the floor polishing and scrubbing machine is being used normally, either the concentrated pressure pad 11 can be removed from the brush hollow or downward pressure from the diaphragm 12 can simply be relieved by maintaining the pressure head 13 in the raised position of FIG. 2. The pressure rod 14 will therefore normally be held in raised position, so as to hold the pressure head up, by a compression spring 18 encircling the upper end of the pressure rod, bearing on the upper end of the motor casing and pressing upward on spring seat 19 which is attached to the upper portion of the pressure rod. From this position the pressure rod 14 and head 13 can be moved downward into the depressed position of FIG. 3 by the application of downward pressure to the spring seat 19. Such downward pressure can be exerted at will and to the degree desired by swinging of a bell crank including a generally horizontal arm 20 and an upright arm 21. Such bell crank is suitably mounted by a pivot 22 which is supported from the upper end of the motor by an upwardly extending bracket 23 shown best in FIGS. 3 and 4.

The horizontal arm 20 of the bell crank has a slot in its outer end to form bifurcations 24 which straddle the upper reduced end portion 25 of the pressure rod forming a stem. The slot between these bifurcations is narrower than the width of the head 26 on the upper end of such stem. The bell crank can be swung in a clockwise direction, as seen in FIGS. 2 and 3, from the position of FIG. 2 to that of FIG. 3 to depress the pressure rod 14 by pulling on Bowden wire 27 attached to the upright arm 21 of the bell crank by the anchoring bolt 28.

The Bowden wire 27 extends upward generally alongside the handle shank 8 through a substantially rigid sheath 29, the lower end of which is supported from the motor by a bracket 30 which is attached to the sheath by an anchoring clamp 31. The upper end of the Bowden wire is secured to an operating lever 32 at a location spaced from the lever-supporting pivot 33 about which such lever swings. The Bowden wire is normally held in its lowermost position by a compression spring 34 which encircles the lower end of the Bowden wire and reacts between the lower end of the sheath 29 and the point of attachment of the Bowden wire to the upright arm 21 of the bell crank.

When the Bowden wire is pulled by swinging of the lever 32 toward its adjacent handle grip 9, the bell crank will be swung so that the horizontal arm is swung downward into the position of FIG. 3, to depress the pressure rod. Such rod movement will press the pressure head 13 against the upper side of diaphragm 12 to bow it downward as shown in FIG. 3 for exerting pressure on the abrasive pad 11. Such pad will be compressed to make it more firm and, at the same time, greater pressure will be exerted by the pressure pad on the floor surface. In addition, the pressure of the diaphragm on the pad will be sufiicient so that, as the rotary brush is turned and the diaphragm 12 is turned with it, the pressure pad 11 will be rotated also.

The rotation of the pressure pad 11 thus effected will be helpful in removing a spot on a floor but the most important consideration is the concentration of pressure which can be exerted on the small area of the pad and consequently by the pad on a corresponding small area of the floor. Such pressure concentration can be effected by applying the weight of the entire polishing and scrubbing machine to the small area covered by the pad 11 instead of to the much larger area on which the brush 2 would bear. It will be noted in FIG. 3 that the pressure rod 14 has been moved down far enough relative to the motor shaft 15 so that such shaft, the motor, the casing and the brush 2 supported from the shaft will be elevated sufficiently to enable the floor-engaging surface of the brush to clear the floor.

Because the pressure head 13 is pressed into intimate engagement with the diaphgram 12 of rubber, such head will be rotated in synchronism with the diaphragm. It is preferred, however, that the pressure rod 14 not rotate. Consequently, it is desirable to provide a thrust bearing between the pressure rod 14 and the pressure head 13 which is shown in the form of a washer or pressure head thrust bearing disk 35 engaged between the upper side of the pressure head 13 and the lower end of the pressure rod 14.

In operation the floor polishing and scrubbing machine can be manipulated in the usual manner by the operator grasping the hand grips 9 on the end of the handle shank 8. At such time as he should notice a black spot on the floor or a stain on the carpet or some other blemish, he can move the machine so that it is centered over such blemish and then pull the lever 32 to the desired extent to shift such porportion of the m-achines Weight as the operator might wish from being supported by the floorengaging surface of the brush 2 onto the pressure pad 11.

Instead of the operator being required to manipulate the lever 32 selectively to obtain the desired pressure of the pad 11 on the floor, reciprocating mechanism can be provided for the pressure rod 14 which will enable the desired pressure application to be achieved in every instance simply by the operator pulling the lever 32 into full contact with the handle grip 9. For this operation mechanism is provided to adjust the length of the downward stroke of pressure rod 14 by manipulation of the control lever, taking into consideration the thickness of the pad 11.

The modified type of mechanism shown in FIG. 5 enables the throw of the bell crank to be altered for a given movement of the control rod 27' and the relative positions of the bifurcated bell crank arm 25 and the actuating lever 32 to be selected. With the actuating lever pressed against its adjacent handle grip 9 the pin 28' can be inserted throuhg a desired hole 36 in the upright bell crank arm 21 and a desired hole 37 in the end portion of the control rod 27 to effect such adjustments.

When the actuating lever 32 is held against the adjacent handle grip 9 the upright bell crank arm 21' can be swung to bring a hole 36 in such bell crank arm into registry with a hole 37 in the end portion of the control rod such that the push rod 14 will be depressed to the lowest position desired by downward swinging of the bell crank bifurcations 24. The pin 28' can then be inserted through such registering holes 36 and 37 and the lever 32 can be released. Whenever the lever 32 is swung again into engagement with the handle grip 9, therefore, the pressure head 13 of the pressure means will be depressed into such tmaximum pressure position. Upon release of the lever the compression spring 18 will swing the b1- furcations upwardly again by pressure of the spring seat 19 on them at the same time that the spring raises the pressure rod 14 into its inoperative position.

By use of the apparatus shown in FIGS. 1 to 5 inclusive wax or detergent can be applied to a portion of the floor alongside the brush 2. As the brush is moved toward such wax or detergent, the action of the brush is to push the wax or detergent along ahead of the brush. Wax or detergent can be applied directly to the pad 11 when such pad is to be used for scouring or scrubbing a floor blemish. The pad may also be used as a wax applicator when it is desired to apply an exceptionally heavy coat of wax to a spot or small area as, for example, in areas subjected to heavy trafiic, such as doorways. In such instance, the pressure rod can be lowered momentarily to apply a daub of wax on the floor and then retracted without performing any substantial polishing or scrubbing action.

In FIG. 7 an expedient for delivering liquid wax or detergent through the hollow motor drive shaft 15 is shown. In this instance the pressure rod 14' has a central duct 38 extending longitudinally through it. T o the lower end of the pressure rod is attached a nozzle 39 which is in communication with the duct 38. This nozzle is in registry with an aperture 40 in the central portion of the diaphragm 12. A hose 41 is connected by a coupling 42 to the upper end of the pressure rod 14' for communication with its duct 38.

As shown in FIG. 6 the hose 41 is connected to a reservoir 43 for containing the liquid wax or detergent. A charge of such wax or detergent can be dispensed through hose 41, duct 38 and nozzle 39 by proper manipulation of the plunger or other control 44. A charge of liquid projected by the nozzle 39 through the diaphragm aperture 40 will be deposited on the floor within the hollow of the annular brush 2 so that it will be trapped as the machine is moved in one direction or another. The liquid in the hollow portion of the brush is engaged by the inner periphery of the brush and rubbed on the floor. None of the liquid deposited in such brush hollow can escape as long as the brush is in contact with the floor except for such liquid as the inner periphery of the brush engages and distributes as the machine is moved across the floor.

No auxiliary pressure pad 11 is shown in FIG. 7 and it will be understood that a liquid-dispensing attachment for the floor polishing and scrubbing machine is not dependent on the provision of a pressure rod 14 except for the purpose of conveying the liquid from the hose 41 through the hollow or bore of the motor drive shaft 15. The nozzle 39 might simply be connected directly to the lower end of such hollow drive shaft and the pressure head 13 and diaphragm 12 could be omitted. In that case, of course, the bell crank 20, 2'1 and its actuating mechanism also could be omitted.

Where the liquid-dispensing mechanism is provided in addition to the pressure rod 14, pressure head 13 and diaphragm 12, an abrasive pad can be used beneath the diaphragm 12 or omitted at will. If an abrasive or scouring pad is used with this type of apparatus, it is preferred that it be of reasonable porous material such as steel woolfWhen this type of pad is used the liquid wax or 8 detergent can be supplied to it through the hose 41 and bore 38 of the pressure rod 14' and dispensed by the nozzle 39 onto the upper side of such pad. The liquid will then pass through such pad, particularly when compressed by pressure by the diaphragm 12 on it, so as to be applied to the floor from the lower side of the pad. In such case the operation of the Bowden wire 27, bell crank 20, 21, pressure rod 14' and pressure head 13 for pressing the diaphragm 12 against the pressure pad will be the same as described in connection with FIGS. 2 and 3 in particular.

As has been discussed above, the elfectiveness of a scrubbing action depends not only on the type of abrasive material used and the concentration of pressure by it onto the floor, but also on the speed of movement of the floorcontacting surface relative to the floor. If the scrubbing pad 11 is located within the hollow brush 2 and simply is driven at the same rotative speed as the brush, as will be the case with the apparatus shown in FIGS. 2 and 3, the actual translational speed of the pad 11 relative to the floor will not be very high. Such relative speed can be increased greatly and virtually to any extent desired by effecting rotation of the pad 11 independently of rotation of the brush 2 and at a considerably higher speed. Mechanism to effect such an operation is shown in FIGS. 8 and 9.

In this instance the pressure rod 14" has an auxiliary motor 45 attached to its head 26 on the upper end of such pressure rod. This motor is supported by the pressure rod but is held in position above the pressure rod by parallel uprights 46 extending upward from the main drive motor 6 and spaced apart a distance slightly greater than the width of the motor. Slots 47 in the upper portions of these uprights receive trunnions 48 projecting from opposite sides of the auxiliary motor. The lengths of slots 47 extend vertically so that such slots guide the motor for upward and downward movement with lengthwise movement of the pressure rod 14 and the trunnions enable the motor to swing as may be necessary to maintain alignment of the motor axis with the axis of the pressure rod.

In this machine there is no diaphragm extending across the hollow of the brush 2, but instead, the pressure head 13' mounted on the lower end of the pressure rod 14" is engageable directly with the upper side of the pressure pad 11. It is desirable for the lower side of such pressure head to be covered with friction material, such as rubber, so that when it is pressed against the pressure pad it will cause such pad to rotate in synchronism with the pressure head. The pressure rod 14" is connected directly to the auxiliary motor 45 so that the pressure head 13' can be rotated at a rotative speed considerably greater than the rotative speed of the brush 2 and its driving head 5.

To control energization of the auxiliary motor 45 a control switch 49 can be mounted on the actuating lever 32 for depressing the pressure rod 14" in the manner described in connection with FIGS. 2 and 3. Alternatively, a switch 49 can be mounted on one of the uprights 46 as shown in FIG. 9 for engagement by a trunnion 48 to effect energization of the motor automatically when the pressure rod 14" has been depressed to a predetermined degree suflicient to press the abrasive pad 11 firmly against the floor by manipulation of the actuating lever 32 to swing bell crank 20, 21 for depressing the pressure rod.

FIGS. 10, ll, 12 and 13 show somewhat diagrammatically the application of an arrangement for applying localized pressure to different types of conventional floor polishing and scrubbing machines. In the machine of FIG. 10, the motor 6 again is located centrally over the casing 1 but, instead of the brush being driven through reduction gearing 7 of the planetary type as shown in FIG. 2, the reduction gearing 7a is of the compound series type. While in this instance the base of the brush 2 is shown as being integral with one gear of the gearing, the brush could be secured to the gearing by a disengageable coupling if desired.

The pressure head 13a is depressible relative to the brush backing by mechanism operating through a bore coaxial with the brush backing. The sheath 50 of a Bowden wire actuator has its upper end extending through and secured in the top of the casing 1. The sheath then extends downwardly next toward the center of the machine and finally downward through the bore in the gearing and the brush back to the pressure head. The lower end of the Bowden wire 51 extending through the sheath has a head received in a cavity provided in a boss in the back of the pressure head so that downward movement of the Bowden wire through the sheath 50 would force the pressure head 13a downward to exert pressure on a polishing or abrading pad 11 beneath it.

Lengthwise movement of the Bowden Wire through the sheath is effected by reciprocating the control rod 27a which is connected to one end of the lever 52 journaled on a pedestal 52' on the casing 1. The other end of this lever is secured to the Bowden wire 51. When the control rod 27a is pulled upwardly in the direction indicated by the broken arrow, the Bowden wire will be pushed downward to depress the pressure head 13a. The force of such downward pressure will react through the lever pedestal 52' to raise the casing 1 sufliciently to relieve most of the pressure from the brush 2. When the control rod 27a is pushed downward again the Bowden wire 51 will be pulled up so that the weight of the machine will be transferred from the pressure head 13a back to the brush 2. Upward movement of the Bowden wire will not actually lift the pressure head but it will be raised by the pressure of the floor on the pressure pad 11.

The pressure head 13a is connected to the back of the brush 2 for rotation with it although the pressure head can move up and down relative to the brush as described above. The pressure head and brush back can be connected for conjoint rotation by a pin 53 projecting upwardly from the pressure head eccentrically of its axis into a downwardly opening socket 54 provided in the brush back. Because the pressure head is thus connected for rotation with the brush back, it is necessary for the connection between the pressure head and the Bowden wire to afford relative rotation between these two elements. For this purpose, the head on the Bowden wire is received loosely in the socket of the pressure head stem receiving the Bowden wire head.

In FIG. 11, the motor 6 is offset from the center of the casing 1 and drives the brush 2 through reduction gearing 7b including a small and external gear driven by the motor 6 which meshes with a large internal gear concentric with and connected directly to the brush. In this construction the pressure head 13a is connected to the lower end of the offset thrust tube 50'. The upper end of this tube extend slidably through an opening in the casing 1 and a head on the lower end of this tube is loosely engaged in a socket on the upper side of the pressure head, so that such head can rotate relative to the lower end of the tube 50'.

The upper end of the thrust tube is pivotably connected to one end of a lever 52 which is, in turn, pivotably mounted on the upper end of a pedestal 52' projecting upward from the top of the casing 1. The opposite end of this lever is pivotably connected to a control rod 27a. Normally the thrust tube is urged upward by a compression spring 50 engaged between the top of the casing 1 and the lever end. By this spring acting on the thrust tube, the pressure head 13a is lifted to its uppermost position shown in FIG. 11. Such pressure head is rotatively connected to the brush back by the pin 53 engaged in socket 54 in the brush back as described in connection with FIG. 10.

The construction shown in FIG. 11 is not only capable of causing the pressure head 13a to exert extra localized pressure when desired, but as mentioned above, the thrust member 50' is a tube. A liquid supply tube 51' is connected to the upper end of the tube 50 for the purpose of supplying liquid wax or detergent to a hole through the center of the pressure head 13a. Such liquid will be supplied to the tube 51' from a suitable reservoir such as shown in FIG. 6, for example, and the supply of liquid can be controlled as discussed in connection with that figure. If there is no pad 11 beneath the pressure head, the liquid will be dispensed directly onto the floor. Otherwise, such liquid will be dispensed onto the upper side of the pad and will soak through it.

FIG. 12 shows a drive motor and brush arrangement like that of FIG. 11, but in this instance the pressure head 13a is depressed by a pressure rod 14 similar to that of the apparatus shown in FIG. 1 instead of being depressed by a thrust tube as shown in FIG. 11. Such pressure rod extends upward into the cylinder 55 of a fluid pressure jack. Fluid under pressure, which preferably is hydraulic liquid but may be air, is supplied to such cylinder through a pressure fluid supply line and control valve 56. From such control valve, ducts extend to opposite ends of the jack cylinder so that fluid under pressure can be supplied through one duct and fluid can be returned through the other duct to a reservoir to make the jack double-acting. Such jack includes a piston 57 received in the cylinder of the jack and mounted on the end of the pressure rod 14 which extends into the jack.

The lower end of the pressure rod 14 is connected to a boss on the upper side of the pressure head 13a in the same manner as that described in connection with FIG. 11 so that the pressure rod and pressure head can rotate relatively. Also, the pressure head is rotatively integrated with the back of the brush 2 by a pin 53 carried by the head being engaged in a socket 54 of the brush back as previously described. As in FIG. 11, the connection between the pressure rod 14 and the pressure head 13a is of the type which will enable the pressure head to be lifted by upward movement of the pressure rod.

Normally the control valve 56 will be set so that fluid under pressure is supplied to the lower end of the jack cylinder 55 for lifting the piston 57, the pressure rod 14 and the pressure head 13a as shown in FIG. 12. When it is desired to exert concentrated pressure on a particular spot, valve 56 is actuated to reverse the supply of fluid under pressure to the jack 55 so that such fluid will be supplied to the upper end of the jack cylinder for forcing the jack piston and pressure rod 14 downwardly. The pressure thus exerted will be yielding, but the projection of the pressure rod 14 from the jack cylinder 55 will tend to lift the casing 1 by reaction from the floor through the pressure head 13a and pressure rod 14. Because of this action, the pressure of brush 2 on the floor will be reduced or it may be possible to lift the brush entirely free of the floor by such an operation.

In the machine shown in FIG. 13, the motor 6 for driving the brush 2 is arranged with the axis of its rotor horizontal whereas the axis of rotation of the brush 2 is vertical. The drive to the brush is accomplished through an external V-belt connecting pulleys on the motor armature shaft and on a shaft carrying one gear of bevel gearing 7c. The latter shaft is carried by the casing 1 parallel to the shaft of the motor armature. The size of the cooperating bevel gears and the sizes of the two pulleys can be selected so as to obtain a proper speed reduction from the motor to the brush. It is preferred that the motor be mounted on the casing 1 so that the shaft of the motor armature extends diarnetrally of the casing.

The pressure head and pressure: rod of this machine are similar to those of the machine shown in FIG. 12. The difference in structure resides in the mechanism provided for raising and lowering the pressure rod for the purpose of raising and lowering the pressure head 113a. In this instance, the pressure rod extends upward through a lower edgewise cam 58a which is secured on the pressure rod. The upper side of this cam is inclined. The upper 1 1 end of the pressure rod extends from such lower edgewise cam upward into a downwardly opening bore in an upper edgewise cam 58b which has a lower inclined sulface adapted to cooperate with the upper inclined surface of the lower edgewise cam.

Relative rotation of the two cams is effected by attaching the lower end of a Bowden wire 27 extending through sheath 29 to a crank projection 58c extending outward from the lower edgewise cam. The upper end of such Bowden wire will be connected to an operating lever 32 mounted on the handle for the machine as shown in FIG. 1. As the handle is pulled, the Bowden wire will rotate the lower edgewise cam 58a and pressure rod 14 toward the position shown in FIG. 13 so that interengagement of the inclined cam surfaces will force the pressure rod and the pressure head downward. The resulting upward pressure on the pressure rod 14 reacting from the floor will produce an upward thrust on the upper edgewise cam 58b so as to lift the machine and the brush 2 upward for supporting the weight of the machine on the pressure head 13a and pad 11 to provide concentrated pressure. When the handle is released or the Bowden wire 27 is pushed downward, cam 58a will be turned in the opposite direction relative to cam 58b so that the machine can settle down again onto the brush 2. This actuating mechanism for the pressure rod 14 enables positive downward thrust to be exerted on it but does not include mechanism to effect a positive upward force on such rod.

The machine of FIG. 14 has the same type of motor and casing arrangement as shown in FIG. 2 in which the brush attaching coupling 4 is connected to the reduction gearing 7. The structure of the brush unit itself, however, differs in that the pressure head portion 13b is integral with the central portion of the brush. The radially outer portion of the brush back is annular and is arranged to slide up and down relative to the central portion of the brush back. Grooves 59a on the inner periphery of the annular brush portion interfit with one or more splines 59b projecting outward from the central portion of the brush for the purpose of rotatively connecting the inner and outer brush back portions. Downward movement of the outer brush portion relative to the inner brush portion is limited by one or more latches 590 in the form of legs pivotably mounted on the bottom of the central brush portion and which can swing outward beneath the outer brush portion.

The outer portion of the brush back carrying the brush 2 can be held in its lower position by one or more pressure feet 6011. If more than one of such pressure feet is provided, they will be distributed circumferentially around the casing 1. Each pressure foot is mounted on the lower end of a pressure spindle 60b which is slidable up and down through an aperture in casing 1 and a collar 60c mounted on and projecting upward from such casing encircling the spindle-receiving aperture. The spindle can be pressed downward relative to such collar and aperture by exerting pressure on the head 60d on the upper end of the spindle and the spindle can be held in a depressed position by a latch pin 60a slidable through the side of collar 600 into a socket hole or groove in the side of the spindle. The latch pin can be pressed inwardly to maintain such holding engagement with the spindle by a spring 60 When the floor polishing and scrubbing machine is being used normally, the pressure spindle or spindles 60b will be held in their lowered positions to keep the outer portion of brush 2 depressed relative to the inner portion of such brush. The weight of the polishing machine will therefore be carried principally by the outer portion of the brush by such weight being transmitted to such brush portion through the pressure spindle or spindles and pressure foot or pressure feet. The pressure foot 60a or the upper side of the brush back or both are made of low friction material to minimize friction between the pressure foot or feet and the brush back as the brush is rotated relative to 12 the casing 1. Alternatively the pressure foot could be replaced by a roller.

When it is desired to apply concentrated pressure to a particular spot on the floor, the latch pin e is pulled outward in opposition to spring 60 until its inner end is withdrawn from the socket in the spindle 60b. The weight of the machine will then be transferred from the pressure spindle or spindles to the pressure head 13b and the pad 11' of cleaning or polishing material beneath it. When the particular spot has been scrubbed or polished sufficiently, the pressure spindle or spindles 60b will be pushed down again and latched so as to transfer the weight of the machine back to the annular brush 2. If desired, a disk of abrading material 2 such as sandpaper can be placed beneath both the brush 2 and the pressure pad 11 for sanding a floor.

The machine of FIGS. 15 and 19 also is generally like that of FIGS. 1 and 2. The brush 2 is received in the recess 3 of the casing 1, and such casing carries the motor 6 which rotates the brush 2 through reduction gearing 7. The brush is mounted by the brush-attaching coupling 4 on the driving head 5. The principal difference between the apparatus shown in FIGS. 15 to 19 and the various types of concentrated pressure apparatus described above is that, in this instance, the concentrated pressure apparatus and its control mechanism are carried principally by the brush so that such mechanism can be added more readily to a floor polishing and scrubbing machine as an accessory.

In this instance, the pressure head 13c is larger than the pressure head 13 of FIGS. 1 and 2. Themechanism for moving such pressure head downward relative to the annular brush 2 includes a braking rod 61 extending through a guide and housing 62 for such rod. A compression spring in such housing encircling the braking rod reacts between the bottom of such housing and a set collar 63' on the rod to push the rod upward, normally, into the position of FIG. 15. The upper end of such rod is rounded and can seat on an insert 52" of antifriction material such as Teflon carried by the swinging end of a lever 52 of channel shape. This lever can be swung by reciprocation of a control rod 27a of the type described in connection with FIGS.10 and 11.

A downwardly tapered conical braking roller 64 is mounted on the lower end of the braking rod 61 for engagement with the beveled periphery of a floating disk 65 which is attached to the pressure head 130 by a plurality of circumferentially spaced posts 66. FIG. 16 shows three of such posts spaced apart The heads of such posts are welded or otherwise secured to the floating disk 65 and their lowers ends may be fitted into sockets in the margin of the pressure head 13c and secured in place by screws as shown in FIGS. 15 and 18. The disk 65 is main tained in its centered position by the guiding cooperation between its central aperture and the exterior of the hub 68 of brush 2 over which it is fitted. Such hub projects upward from the brush and carries the brush attaching coupling 4 engaged with the driving head '5, which is rotated by motor 6 through reduction gearing 7.

When the braking roller 64 is out of engagement with the inclined edge of disk 65, such disk will be maintained in its raised position of FIG. 15 by compression springs 67 encircling the respective posts 66 and engaged between the upper side of the brush back and the lower side of the disk 65. Also, the disk 65 will be turned in synchronism with the brush 2 by a large torsion spring 67' encircling the hub 68 and having one end engaged with such hub and its other end anchored to plate 65, as shown in FIGS. 15 and 18. The disk 65, posts 66 and pressure head can, however, turn through a small angle relative to the brush back in the direction opposite the rotation of the brush because the posts extend through slots 69 elongated circurnferentially of the brush back as shown in FIG. 16.

In FIGS. 15 to 19, pressure head guides are shown which guide the relative elevational movement of the pressure head 13c and the brush back. Each of these guides includes an inclined row of rollers 71 mounted in a downwardly opening recess in the brush back which are engaged by the upper inclined surface of a wedge block 72 carried by the upper side of the pressure head 13c. As downward pressure is exerted by the roller 64 on the margin of the floating disk 65 by downward movement of the rod 61 caused by tilting lever 52 from the position shown in FIG. 15 to that of FIG. 18, the wedging action of the wedges 7'2 presses the pressure head 130 downwardly in opposition to the force of compression springs 67 so that such pressure head will be moved from the position of FIG. 15 to that of FIG. 18 while the pins 66 move along the slots 69 in the direction opposite the direction of rotation of the brush. Such turning of the disk 65 relative to the brush will be in opposition to the torsional driving force exerted by torsion spring 67' between the hub 68 and the disk.

When the braking effect of the roller 64 on the rim of disk 65 has caused such disk to move so that the posts 66 have again come into a position of equilibrium in the broken-line positions of FIG. 16 with the pressure head 13c depressed to the position of FIG. 18, the roller 64 again will be driven at a speed corresponding to the speed of rotation of disk 65 and brush 2 and the upper end of braking rod 61 will slip relative to its Teflon seat 52". Such slipping action will continue as long as the braking rod is held in the depressed position of FIG. 18.

When the upward force on control rod 27a is released, the compression spring 62 will raise the braking rod 61 to withdraw the braking roller 64 from engagement with the periphery of disk 65. The springs 67 will promptly move disk 65 and pressure head 13c upward relative to the brush back to the position of FIG. 15 so that the concentrated pressure is no longer exerted by the pressure head. Simultaneously, the torsion spring 67' will turn the disk 65, pressure head 13c and posts 66 relative to the brush in the same direction that it rotates until the posts are again in engagement with the leading ends of the slots 69 as shown in FIG. 16. The brush 62 can then effect its customary scrubbing or polishing operation.

The pressure head 130 shown in FIGS. 15 and 18 is of circular shape having a marginal rib by which a greater pressure would be exerted on the pressure pad 11' than would be exerted on it by the recessed central portion of the pressure head. In FIG. 20, a pressure head 13d of a different type is shown having ribs radiating from its central portion. It will be understood that pressure heads of various other designs could be used if desired.

In the floor polishing and scrubbing machine of FIG. 21 the various components are similar to those of the machine shown in FIGS. 15 to 19 except that, in this instance, an annular type of concentrated pressure member 1312 has been substituted for the disk type of pressure head shown in FIGS. 15, 18- and 20. Such annular pressure head fits into a downwardly opening annular groove in the back of the brush 2. In this instance, the pressure head posts 66' have their lower ends secured directly in the upper side of the pressure head ring. In this instance, the actual floor-engaging element can be a disk underlying the brush 2 and pressure head ring 132. Such floor-engaging member may be a mat of steel wool or a sandpaper disk or a felt pad. Since the mechanism utilized for raising and lowering the pressure head is the same as that described in connection with FIGS. 15 to 19, such descrip tion need not be repeated. In this instance, however, the wedge blocks 72 can be formed as integral parts of the ring 13c.

In the floor scrubbing and polishing machine of FIGS. 22 to 25 the member previously designated as a brush 2 is replaced by a back 2 having a flat annular lower surface bearing on a polishing or abrading pad 2 which is the equivalent of a scrubbing or polishing brush. The backattaching coupling 4 secures the brush back 2 to the driving head 5 which is rotated by the motor '6 through the speed-reducing gearing 7. In this instance the pressure head for exerting concentrated pressure is carried by or forms a component of the removable brush back 2. While such pressure head could be simply a ring comparable to the ring 13e of the structure shown in FIG. 21, it is preferred that the pressure head ring 13 shown best in FIGS. 23 and 24 carry on its underside somewhat resilient projections 13g which are spaced circumferentially of the ring 13 The aggregate area of the projections 13g contacting the floor engaging pad 2' is considerably less than the total area of the ring 137". When this ring is depressed so that the projections 13g are below the general lower surface of the back 2, such pressure head components will cause the corresponding small portions of the pad 2' to bear primarily on the floor.

In this instance also, depression of the annular pressure head 13 13g is effected by braking mechanism. Moreover, the brake-actuating mechanism used in this machine is similar to that described in connection with FIGS. 15 and 18. Thus, the brake-actuating mechanism includes the vertically reciprocable rod 61 extending through the housing and guide 62. Such rod is normally held in the upper position by the compression spring 63 received in the housing and engaged between the bottom of the housing and the set collar 63' on the braking rod. Such rod is depressed by swinging lever 52 mounted on pedestal 52, one end of which lever is engaged with the upper end of rod 61 and the other end of which is connected to control rod 27a. A braking pressure foot 64 is carried by the lower end of rod 61.

Spaced flanges 73 project upward from the annular pressure head 13 at opposite ends of the projections 13g. These flanges fit slidably within cavities 74 spaced circumferentially of the brush back 2 as shown in FIGS. 23 and 24. A control ring 75 overlies the several cavities and is connected to the concentrated pressure head ring 13 by means to effect depression of such ring.

The thrust mechanism interconnecting the pressure head ring 13 and the control ring 75, which is shown in FIGS. 22 to 26 inclusive, includes a thrust loop 76 having its lower end pivoted in an anchor block 77 carried by the pressure head ring 13] and its upper end pivoted in the anchor block 78 carried by the control ring 75. While the flanges 73 on the pressure head ring 13) engaged in the cavities 74 of the brush back 2 prevent such ring 13 from shifting circumferentially relative to the brush back, the control ring 75 can shift circumferentially relative to the brush back, but only to the extent permitted by the thrust loop 76 which connects the two rings.

As the ring 75 moves circumferentially relative to the back 2 and the pressure head 13 from the position shown in FIG. 23 to that of FIG. 24, the angle of the thrust link changes relative to the two rings so as to force them apart. Normally, these rings are held in their relationship of closest approach to each other shown in FIG. 23 by strong tension springs 79 extending respectively through the thrust loops 76. Anchoring loops on the opposite ends of such springs are engaged respectively in apertures of lugs 81 on the upper side of pressure head ring 13 and lugs on the lower side of control ring 75. As the control ring is moved circumferentially or" the brush back 2 from the position of FIG. 23 toward the position of FIG. 24, the change in angular relationship of thrust loop 76 to the two rings will force them apart. Such relative movement of the rings will stretch spring 29 in the manner indicated in FIG. 24 which tends to shift the ring 75 circumferentially back to the position shown in FIG. 23.

As indicated in FIG. 24, the circumferential movement of ring 75 moves the thrust loops 76 into positions to force apart the pressure head ring 13 and the control ring 75. Backing clips 82 are engaged over the opposite edges of the control ring 75 at the locations of the pressure head projections 13g as shown in FIGS. 25 and 26. Such backing clips limit the movement of the control ring upwardly from the brush back 2 and consequently the thrust force exerted by the loops 76 moving from the position of FIG. 23 toward the position of FIG. 24 effects movement of pressure head ring 13 downward relative to the brush back 2 from the position of FIG. 23 toward that of FIGS. 24, and 26 to exert concentrated pressure on corresponding areas of the pad 2'.

As indicated by the arrows in FIGS. 23, 24 and 25, the brush back 2 is turning in the direction opposite that in which the control ring 75 must move relative to such back in order to eflect the downward movement of the pressure head ring 13 relative to the brush back described above. Such relative movement can be accomplished by applying a braking force to the control ring so as momentarily to deter movement of such control ring with the rotating brush back 2. Such braking force is applied to the control ring by reciprocating downward the braking rod 61 to press the braking foot 64 on its lower end against the upper side of the control ring 75. Excessive friction between the control ring and the brush back 2 is avoided by providing two ribs 83 of antifriction material, such as Teflon, extending along opposite edges of the control ring to bear on the upper side of the brush back 2. The degree of circumferential shifting of the control ring 75 relative to the brush back by such application of braking force is limited by the engagement of a stop lug 84 projecting from an edge of such control ring with a stop boss 85 projecting upward from the brush back 2 as shown in FIGS. 24 and 25.

As shown best in FIG. 23, in the particular form of machine represented by FIGS. 22 to 26 inclusive, the brush element may include a back 2 having a facing 2 on its lower surface which may be resilient for engaging the pad 2'. When the pressure head ring 13f, 13g is depressed relative to the brush back 2, the concentrated pressure head projections 13g will first be moved down into engagement with the pad 2' from the positions shown in FIG. 23 if they are not engaged with the pad and further circumferential shifting of control ring 75 relative to the brush back will then cause the thrust loops 76 to lift the control ring which, in turn, will raise the brush back to a position such as shown in FIGS. 25 and 26 by lifting force transmitted through the backing clips 82. The braking rod 61 can be held down in its brake-applying position as long as concentrated pressure of selected portions of pad 2' on the floor is desired. When the downward pressure on braking rod 61 is relieved, spring 63 will raise such rod to retract pressure foot 64' from engagement with the control ring whereupon the weight of the machine and the force of springs 79 will shift control ring 75 circumferentially in the opposite direction from the position of FIG. 24 to the position of FIG. 23. Such shifting of the control ring will tilt the thrust loops 76 back to the position of FIG. 23 so that the springs 79 can raise the

pressure head

131, 13g back into the position of FIG. 23.

In FIGS. 27, 28 and 29, a somewhat different type of thrust mechanism is shown. In this machine, thrust struts 76 are substituted for the thrust loops 76 of the machine shown in FIGS. 22 to 26 inclusive. The lower end of each thrust strut has a ball 77 engaged in a socket in the upper side of a pressure head disk 1311. A ball 78 on the upper end of each thrust strut 76' is engaged in a socket in the lower side of the control ring 75. Instead of the pressure head 1311 being, or being associated with, an annular ring, such pressure head may be circular as shown in FIG. 29 and may be engageable with the upper side of a pressure head in the form of a flexible diaphragm 13i which is made of rubber or other resilient material.

When the braking foot 64' is moved downward from a position such as shown in FIG. 27 into contact with the upper side of the control ring 75 as shown in FIG. 28, the resulting circumferential shift of the control ring will alter the angle of the thrust strut 76' such as from that shown in FIG. 27 to that of FIG. 28. Since the control ring is held by clips 82 from moving upward away from the brush back, the struts will force the pressure head 13h downward against the flexible pressure head 13i which in turn will be pressed against corresponding locations of the pad 2. The pressure head disks 13h will be guided for movement down below the bottom the brush back 2 by posts 86 spaced diametrally of the pressure head disk and slidably received in bores of the brush back as indicated in broken lines in FIGS. 27 and 28. When the brake foot 64' is raised from engagement with the control ring, the weight of the machine exerted on the thrust struts 76 and the resilience of the pressure head members 13i will shift control ring 75 circumferentially relative to the brush 2 in the direction in which such brush is rotating and will retract the pressure head disks 13h from the position shown in FIG. 28 to that of FIG. 27 until the braking foot again is engaged with the control ring 75 to effect the next concentrated pressure operation of the machine.

FIGS. 30, 31 and 32 show a floor scrubbing and polishing machine in which the concentrated pressure head is formed by a tube 13j mounted on the bottom of the brush backing which is inflatable and thereby expandable from the flattened condition shown in full lines in FIGS. 30, 31 and 32 into the broken-line condition of FIG. 31 in which the tube presses against a localized area of the scrubbing or polishing pad 2 beneath it. Air under pressure is supplied to the tube through a conduit 87 to inflate it. One end of such conduit is connected to the tube and the other end is connected to an air pressure controlling cylinder 88. Compressed air is supplied to such cylinder from a tank or reservoir 89 provided in the brush back 2 under the control of an air supply control member including a stem and a piston 91 carried by the stem, received in the cylinder 88 and sealed relative to such cylidner by sea1 ing rings 92 which are spaced axially of the piston.

A port 93 through the wall which is common to the compressed air tank 89 and the cylinder 88 is located between the two sealing rings 92 when the piston 91 is in its uppermost position of FIG. 31. A piston port 94 through the piston head establishes communication between the portion of the cylinder 88 above the piston and the portion of the cylinder below the piston at all times. Normally, a compression spring in the cylinder holds the piston '91 up in its uppermost position so that port 93 will be located between the sealing rings 92 which will prevent air passing from the reservoir 89 through the port 93 either into the portion of cylinder 88 above the upper ring 92 or below the lower ring 92. The stem 90 is hollow and it has a bleed opening 96 through its upper end for exhausting air under pressure from the cylinder to the atmosphere.

If the air supply controller stem 90 and piston 91 are moved downward until the upper sealing ring 92 of the piston is below the port 93, air under pressure can flow from the compressed air supply tank 89 reasonably freely through the port 93 to the upper portion of the cylinder 88 and through the piston port 94 to the lower portion of the cylinder 88 and the conduit 87 for inflating the concentrated pressure head tube 13j. Air Will leak from the cyl linder to the atmosphere through the hollow stem 90 and bleed opening 96 but the ports 93 and 94 are so much larger than such bleed opening that the concentrated pressure tube 13 will remain inflated as long as the upper sealing ring 92 of the pressure control piston is below the air supply port 93. When spring 95 moves piston 91 upward to its uppermost position of FIG. 31, the supply of air under pressure to cylinder 88 through ports 93 and 94 will be cut off and air will gradually bleed from the cylinder, conduit 87 and tube 13 through the bleed port 96 to the atmosphere so that the pressure head tube will deflate.

In order to move stem 90 down into position for elfecting a supply of air under pressure from the reservoir 89 through ports 93 and 94 to conduit 87, a tiltable plate 97 is mounted on the rotatable brush 2 for rotation with it. Normally, such plate is held in a horizontal position paralllel to the brush back by a compression spring 98 interposed between the upper side of the brush back and the lower side of the plate 97 and encircling a telescoping guide rod 99. The upper side of control plate '97 bears against the underside of head 100 on the upper end of such telescoping guide rod. The periphery of control plate 97 can be depressed at one location by a roller 101 movable downward into engagement with the periphery of the control plate but which roller is not shiftable circumferentially of the plate. Such roller can be moved downward by mechanism such as illustrated for controlling the elevational position of the braking roller 65 in FIGS. and 18 or the braking foot 64' in FIG. 22.

When the control wheel 101 is depressed from the solid line position of FIG. 31 to the broken-line position of that figure, the wheel will engage the upper surface of the control plate 97 at one location and tilt it into the brokenline position illustrated in opposition to the force produced by spring 98. The bottom of such tilted plate will engage the upper end of the control member spindle 90 and move it downward sufliciently so that the upper sealing ring 92 of piston 91 will be shifted below the air supply port 93. As the brush 2 and control plate 97 rotate away from the location of the wheel 101, however, the portion of the control plate above the stem 90 will rise and spring 94 will move the control piston upward correspondingly, until it has again reached the position shown in full lines in FIG. 31 in which the port 93 will be effectively closed. The portion of control plate 97 above stem 90 will continue to move upward until it reaches a position diametrally opposite wheel 101 and thereafter as such portion of the plate continues to rotate toward wheel 101, such portion will be moved downward again until it reaches the brokenlme position shown in FIG. 31 as it again passes beneath the wheel 101. As the brush 2 rotates, therefore, the control stem 90 and piston '91 will be alternately depressed and raised to supply air intermittently to the conduit 87 and tube 13 Because the bleed port 96 is quite small, however, the tube 13f will remain inflated as long as the wheel 101 is maintained in its lowered position even though air under pressure will be supplied only intermittently to the tube 13 through the cylinder 88.

The compressed air supply reservoir 89 carried by the brush 2 could be supplied with compressed air periodically. It is preferred, however, to incorporate an air pump in the machine which will operate automatically to pump air into the reservoir at least whenever air is being withdrawn from it for inflating the pressure head tube 13 or even more frequently, if desired. Such pump mechanism is shown in FIG. 30. The pump element includes a stem 102 carrying a piston 103 which is received in a cylinder 104 in the brush back 2. Such piston is sealed relative to the cylinder 104 by sealing piston rings 105. Normally, such piston is maintained in the upper position shown in FIG. by a compression spring 106 engaged between the bottom of the cylinder and the piston 103. In the bottom of the cylinder is an air supply port 107 controlled by a check valve which prevents air from being forced out of the cylinder through such port. A port 108 controlled by a check valve establishes communication between the cylinder 104 and the compressed air reservoir 89 but prevents air from flowing from such reservoir to the pump cylinder. A vent 109 for the reservoir is controlled by a pressure relief valve so as to limit the maximum pressure which can be built up in the reservoir.

The pump mechanism shown in FIG. 30 is operated by the same control wheel 101 as is used to effect inflation of the inflatable pressure head tube 13 as described in connection with FIG. 31. It is preferred, however, that the stem 102 of the pump mechanism be longer than the stem 90 of the tube-inflating control mechanism so that the pump mechanism will be actuated by moving wheel 101 downward through a smaller distance to tilt control plate 97 into the broken-line position shown in FIG. 30.

When the plate is in this position, its lower side would not contact the upper end of the stem if such stern were in radial alignment with the wheel 101. Each time the stem 102 passes the circumferential location of wheel 101 in its lowered broken-line position of FIG. 30, the pump stem 102 will be depressed at least to some extent to force air from cylinder 104 through port 108 and past its check valve into the reservoir 89. As the plate 97 rises, spring 106 will raise piston 103 so as to draw air through port 107 past its check valve into cylinder 104 for replenishing the air forced by descent of such piston from the cylinder into the reservoir 89. It will be appreciated that the farther wheel 101 is moved downward, the more control plate 97 will be tilted as the brush 2 rotates and consequently the farther downward pump stem 102 will be forced during each revolution. The length of stroke of piston 103 thus effected will determine the amount of air pumped :from cylinder 104 into compressed air reservoir 89 during each revolution of the brush.

In addition to exerting concentrated localized pressure for cleaning or polishing when desired with the machine shown in FIGS. 30, 31 and 32, it is also possible with this machine to dispense detergent or polishing liquid periodically when desired. Mechanism for effecting such a liquid dispensing operation is shown in FIG. 32. A stem 110 carries a piston 111 which is received in a cylinder 112. Sealing rings 113 provide a seal between such piston and its cylinder. A compression spring 114 engaged between the bottom of cylinder 112 and the piston normally maintains such piston in the raised position shown in FIG. 32. Liquid is dispensed from the cylinder 112 through an outlet 115 controlled by a check valve. Liquid is supplied to the cylinder from a tank 116 in the brush back 2 through a conduit 117 which is controlled by a check valve 118.

From a comparison of FIGS. 30, 31 and 32, it will be seen that the concentrated pressure control stem 90 of FIG. 31 is shorter than the pump-actuating stern 102 of FIG. 30 and that the liquid dispenser stem 110 of FIG. 32 is shorter than the concentrated pressure control stem 90 of FIG. 31. Consequently, if control wheel 101 is in the full-line position shown in all of these figures, the control plate 97 will not be tilted at all. If the control wheel is moved downward to the broken-line position shown in FIG. 30, the control disk 97 will be tilted sufficiently so that the pump stern 102 will be reciprocated to some extent. If the control wheel 101 is lowered to the position shown in broken lines in FIG. 31, both the pump stem 102 and the concentrated pressure stem 90' will be reciprocated as the brush revolves so that, because of its longer stroke, the pump piston 103 will pump more air into the reservoir 89 and the pressure head tube 13j will be inflated. If the control wheel is lowered still farther to the broken-line position of FIG. 32, the control plate 97 will be tilted still more to the broken-line position of FIG. 32 in which it will engage and depress the liquid-dispensing stem 110.

The amount of liquid dispensed by reciprocating the stern 110 will be dependent on the degree to which the control plate 97 is tilted. The downward reciprocation of the stem 110 once each revolution will cause the piston 111 to discharge a squirt of liquid through the discharge nozzle 115. Between squirts, the upward movement of piston 111 effected by spring 114- will draw liquid from the tank 116 through conduit 117 and past check valve 118 to replenish the supply of liquid in the cylinder. Because stem 110 is shorter than stem 90 of the concentrated pressure controller, dispensing of liquid from tank 116 can be accomplished only when concentrated pressure is also being applied to the pad 2 by the inflated pressure tube 13 Also, because the concentrated pressure controller stem 90 is shorter than the pump stem 102 of FIG. 30, the pump will always be operating when the concentrated pressure control is in the pressure-exerting position.

While, as mentioned above, the structure shown in FIGS. 30, 31 and 32 will enable liquid to be dispensed only when the concentrated pressure mechanism is actuated, the devices shown in FIGS. 33 to 37 inclusive enable liquid to be dispensed at will but without having any concentrated pressure mechanism. In each instance delivery of liquid is eifected by reciprocation of a rod 61 downward by mechanism similar to that disclosed in FIGS. 15, 18 and 22. In the device shown in FIG. 33, liquid is dispensed from a tank 119- in the brush back 2 which opens downward. The open side of such tank is closed by a plate 120 secured in place by screw threads .121. Such plate can be rotated to apply it or to remove it by engaging lugs of a special wrench in sockets 122 opening downwardly.

Liquid is discharged from the tank 119 through a hole 123 in the cover 120, which hole is sufiiciently small so that the liquid will not drip out of the hole when the pressure in the tank is atmospheric. Alternatively, or in addition, liquid can be dispensed from the tank 119 through a passage 124. Pressure can be exerted on the liquid in the tank 119 in excess of atmospheric pressure for the purpose of dispensing such liquid by moving downward a flexible diaphragm 125 forming the top of the liquid tank such as to the broken-line position shown in FIG. 33. Such movement can be effected by exerting on the upper side of the diaphragm a pressure greater than atmospheric pressure. For this purpose, a piston 126 is provided in a cylinder 127. Normally the piston is held in its upper position by a compression spring 128. The piston is moved downwarl by downward reciprocation of the piston rod 129 effected by application of pressure to the head 130 on the upper end of such piston rod. Such pressure is exerted by a roller 131 carried by stem 61 which rolls over a hinged plate 132 overlying the piston stem head, as shown in FIG. 35.

Air can be admitted from the atmosphere to the cylinder 127 through a duct 133 in the brush back 2 past a check 'valve 134. Downward movement of piston 126 in the cylinler will force air from it through passage 135 and past a check valve 136 into the chamber 137 above diaphragm 125. As the brush turns, the roller 131 will depress the piston 126 each time it passes roller 131. Thus the liquid will be dispensed from the tank 119 in squirts. An air discharge duct 138 establishes communication between chamber 137 and atmosphere through a bleed outlet 139 so that, each time it is desired to dispense liquid, it will be necessary to build up the pressure in chamber 137 again. Alternatively, the element 139 could be a pressure relief valve. A vent passage 140 is also connected to the air discharge duct 135 so that air can be discharged to the atmosphere through a bleed outlet 141. Consequently, air under pressure will not be stored in the cylinder 127 for any appreciable period of time but will be developed by reciprocation of the piston 126 by a few revolutions of the brush 2 when it is desired to efiect a liquid-dispensing operation.

In the apparatus of FIG. 34, the air supply mechanism is the same as that shown in FIGS. 33 and 35. In this instance, however, the liquid to be dispensed, instead of being stored directly in a tank 119, is contained in a tube 142 of metal or plastic. The material in such tube could be of wax consistency if desired. Air under pressure supplied from duct 135 past valve 136 to chamber 137' will collapse tube 142 progressively to force its contents out of the discharge spout 143 into the duct 124 from which it is dispensed.

The apparatus of FIG. 36 again includes mechanism for producing air under pressure like that shown in FIGS. 33, 34 and 35. In this instance, however, the tank 144 held in a cavity of the brush back 2 by retaining bands 145 is substituted for the tank'119 formed by the cavity itself as shown in FIG. 33 and for the collapsible tube 142 of FIG. 34. The contents of the tank 144 may be pressurized such as by an aerosol to eject a pressure spray 146 when the head 147 is depressed relative to the tank. Depression of such head can be elfected by a pin 148 engageable with it and carried by a plunger 149 reciprocable in the passage 135. Such plunger has a bleed opening 150 through it and normally is urged to the left into the solid-line position by a compression spring 151 encircling the pin 14 8 and bearing against the plunger 149.

As the piston rod head and plate 132 pass under the lowered roller 131, air will be drawn into the cylinder 127 through the duct 133 past the check valve 134. When the piston is driven downward, air will be forced out of the cylinder through duct to press plunger 149 to the right so that pin 148 will be pressed against the head 147 of the aerosol can to effect a liquid dispensing operation. As soon as reciprocation of the piston 126 stops, air will bleed from the passage 135 through the duct to relieve the pressure in the passage 135 so that spring 151 can return the plunger 149 to the left and withdraw pin 148 so that the aerosol tank dispensing valve can close,

In the machine shown in FIG. 37, the liquid in the tank 152 is pressurized in any suitable manner such as by supplying gas under pressure through the passage 153 controlled by a check valve. Such pressurized liquid will be pushed into duct 154 but it cannot pass through the valve passage 155 in plunger 156 as long as the valve is held in the raised position shown in FIG. 37 by the compression spring 157 in the cylinder 158 beneath the valve. When the roller 131 is moved downward to depress the valve stem 129 intermittently in opposition to the force of spring 157, liquid will be discharged from the tank 152 correspondingly intermittently through the duct 154 and valve passage 155 into the discharge duct 159.

The floor polishing and scrubbing machine shown in FIGS. 38 and 39 has mechanism operable alternatively for exerting concentrated pressure on small areas of the pad 2 and for dispensing detergent or polishing liquid. In this instance, however, the concentrated pressure exerting apparatus and the liquid dispensing apparatus cannot be operated simultaneously. The concentrated pressure element 13k shown in FIGS. 38 and 39 is located near the circumference of the brush back 2. Such concentrated pressure element has a skirt 160 slidable in a cylinder 161 formed in the brush back. A stem 162 extends upward from the central portion of the concentrated pressure element 13k and downward movement of such stem will project the concentrated pressure element from the retracted position shown in FIG. 39 downward and outward to the position shown in FIG. 38 for exerting concentrated pressure on the pad 2'. Downward movement of stem 1 62 is accomplished by tilting annular control plate 163- from the broken-line position to the solid-line position shown in FIG. 38.

By tilting one circumferential portion of plate 163 from the position of FIG. 39 to that of of FIG. 38, the plate presses on the head cap 164 of stem 162. Local depression of the edge of plate 163 at a particular circumferential location can be accomplished by lowering control wheel 165 which is carried by the lower end of control rod 166. The head 167 on such control rod can be engaged by a lug 168 projecting from one end of a rocker 169 pivoted generally centrally. Such rocker can be tilted by applying a foroce in one direction or the other to arm 170. The head 167 of rod 166 is held in engagement with lug 168 by compression spring 171 encircling such rod.

As long as the rocker 169 is kept tilted sufficiently to hold wheel 1 65 down in the position shown in FIG. 38, the plate 163 will be tilted downward into the solid-line position at the location of the wheel which corresponds once during each revolution to the location of stem 162. As the circumferential location of the concentrated pressure unit 13k turns away from the location at which wheel 1465 is mounted on casing 1, compression spring 172 enclrcling stem 173 which has been compressed by downward tilting of plate 163 will expand to move the plate progressively away from the head 164 of the pressure element stem 162 during the next half revolution. Upward movement of the plate will be limited by its contact with the bottom of head 174 of stem 173. However, it is desirable to maintain such pressure head substantially in its downwardly projected position in all rotative positions of the brush 2 as long as the control wheel 165 is maintained in its lowered position. The pressure head is held in such position by supplying liquid to the interior of cylinder 161 through conduit 175 from the liquid supply tank 152. Such liquid may be polishing or detergent liquid and preferably is under pressure in such tank.

In the end of conduit 17S adjacent to cylinder 161 is a check valve 176 which is normally held closed by spring 177. The check valve element has grooves in its circumference so that when it has been moved away from its seat, liquid will flow freely through the conduit 175 past such check valve into the cylinder 161. As soon as the liquid pressure in conduit 175 and in cylinder 161 are substantially equalized, however, spring 177 will close the check valve. If the pressure in cylinder 161 then exceeds the pressure in conduit 175, liquid will bleed back through the bleed aperture in the center of the valve 176 until the pressure on opposite sides of the valve has been substantially equalized.

When the brush back 2 has been rotated from the position shown in FIG. 3-8 sufiiciently so that spring 172 has raised plate 163 to the broken-line position, downward pressure will no longer be exerted by the plate on the head 164 of stem 162. During downward movement of pressure head 13k, however, the volume of cylinder 161 will have increased thus reducing the pressure in the cylinder and causing liquid to flow through the conduit 175 from tank 152 to fill the enlarged volume of the cylinder. Downward pressure of the weight of the machine will tend to force pressure head 13 k upward to reduce the volume of cylinder 161 again, but the liquid in such cylinder can escape only slowly through the bleed aperture of valve 176 to the conduit 175. Consequently, the pressure head 13k will be retracted only to a slight extent during the portion of the rotation of plate 163 during which the pressure head is out of substantially the radial position of roller 165. When this roller is raised to the elevated position of FIG. 39, however, the pressure of the floor on pressure head 13k will force liquid from the cylinder 161 back through the bleed orifice of valve 176 so that the pressure head will be restored to its retracted position of FIG. 39 within a few revolutions after the wheel 165 has been raised.

When the pressure head 13k is in its raised position of FIG. 39, polishing or detergent liquid can be dispensed from cylinder 161 to the pad 2' through a discharge aperture 178 in the bottom of the pressure head. Discharge of liquid through such aperture normally is prevented by a check valve 179 located in the bottom of the hollow stem 162. Liquid can be dispensed at will by reciprocation of plunger 180, the upper end of which projects upward through the cap 164 on the upper end of stem 162 and through an aperture 181 in plate 163. A small plate or flap 182 overlies this aperture and is engageable by a wheel 183 carried by a stem 184 having a head 185 on its upper end. This stern can be depressed by engagement with it of lug 186 projecting from the end of rocker 169 remote from that carrying lug 168.

When the rocker 169 is rocked oppositely from its position shown in FIG. 38, lug 186 will engage the head 185 of stem 184 to press such stem downward through casing 181 so that wheel 183 will roll on flap 182 and press it against the upper side of plate 163 if such plate is in the raised position shown in broken lines in FIG. 38 and in solid lines in FIG. 39. When the pressure of lug 186 on head 185 is removed by tilting the rocker 169 in the opposite direction, compression spring 187 encircling rod 184 and reacting between the casing 1 and the head 185 of such rod will raise the rod and wheel 183 upward again into the solid-line positions shown in FIG. 38. Depression of flap 182 from the position shown in FIG. 38 to that of FIG. 39 will move downward the plunger stem 180 and the piston 188 carried by such plunger near the upper end of stem 1-62. The head on the lower end of the plunger will move from a position above aperture 189 in the side wall of stem 162 to a position below such aperture such as shown in FIG. 39. Such downward movement of the plunger will expel a small amount of liquid from the hollow of stem 162 past check valve 179 and discharge it through aperture 178 in the bottom of the pressure head 13k. When wheel 183 rolls off flap 182, compression spring 190 beneath plunger 180 will raise the plunger again until its lower end is above the aperture 189. Each time the wheel 183 passes over the fiap 182 during rotation of brush 2, the plunger 180- will be reciprocated downward to eject a further increment of liquid through aperture 17 8.

The tank 152 can be filled through an aperture in closure plate when the machine is upside down. Such aperture can be closed by a plug 191.

I claim:

1. A floor polishing and scrubbing machine comprising a casing, a unidirectional motor mounted on said casing and including a drive shaft held against axial movement relative to said casing and rotatable about an upright axis, floor-engaging means secured to the lower end of said drive shaft for rotation therewith, a floor-engaging pressure element engageable with a substantially smaller area of the floor than engageable by said floor-engaging means for applying localized concentrated pressure on the floor, and actuating means operable to press said floor-engaging pressure element against the floor while said floor-engaging means is being rotated by said drive shaft with a unit area pressure exceeding the unit area pressure of said floor-engaging means against the floor.

2. A floor-polishing and scrubbing machine comprising a casing, drive means carried by said casing and including a drive shaft rotatable about an upright axis, floor-engaging means disengageably connected to said drive shaft for rotation thereby, a floor-engaging pressure element engageable with a substantially smaller area of the floor than engageable by said floor-engaging means and carried by said floor-engaging means for applying localized concentrated pressure on the floor separate from said floor-engaging means, and control means carried by said casing and movable relative to said floor-engaging means to actuate said floor-engaging pressure element to exert such localized concentrated pressure on the floor.

3. The machine defined in claim 2, in which the floorengaging means includes a hub and an annular member encircling said hub, said hub and said annular member being relatively movable elevationally, and the fioorengaging pressure element is located beneath said hub and inwardly from said annular member.

4. The machine defined in claim 2, in which the control means includes a control member operatively connected to the pressure element and carried by and movable relative to the floor-engaging means to eifect downward movement of the pressure clement relative to the floor-engaging means, and means carried by the casing and engageable with said control member to effect movement thereof relative to the floor-engaging means.

5. The machine defined in claim 4, in which the control member is mounted on the floor-engaging means for limited rotation relative thereto, and the means carried by the casing include brake means for eifecting such limited rotation of the control member relative to the floorengaging means.

6. The machine defined in claim 5, in which the control member is a circular plate located above the pressure element and the brake means are engageable with the margin of said plate, and wedging means engageable between the fioor-engaging means and said plate, operable by relative turning of said plate and the floor-engaging means to move said plate and the pressure element downward.

7. The machine defined in claim 4, in which the control member is a circular plate tiltable relative to the floorengaging means, and the control means further in- 23 cludes a stem engageable by said plate when tilted to depress said stern for moving the pressure element downward relative to the floor-engaging means.

8. The machine defined in claim 2, in which the control member is a ring, and thrust means connected between said ring and the pressure element to effect downward movement of the pressure element relative to the floor-engaging means by said thrust means in response to rotation of said ring relative to the floor-engaging means.

9. The machine defined in claim 8, in which the thrust 10 means includes a tiltable thrust loop.

10. The machine defined in claim 8, in which the thrust means includes a tiltable strut.

11. The machine defined in claim 2, in which the 15 24 floor-engaging pressure element is offset from the axis of the drive shaft.

References Cited UNITED STATES PATENTS 1,707,575 4/1929 Schooling 15-49 1,773,992 8/1930 Gillis 1549 2,300,138 10/1942 Steele 1549 2,728,928 1/1956 Beeren l529 2,930,056 3/1960 Lappin 15-49 EDWARD L. ROBERTS, Primary Examiner U.S. Cl. X.R. 51-177