US2854953A - Fluid-actuated fastener-applying machine - Google Patents

Description

5 sheets-sheet 1 l 77 v 5f/ r 73 a3 84 F/G L. M. OSBORNE FLUIDj-ACTUATED FASTENER-APPLYING MACHINE if -..f mmwmmmwmmm w oct. 7, 1958 Filed Oct. 17. 1955 Oct. 7, 1958 v L, M. osBoRNE 2,854,953

FLUlD-ACTUATED FASTENER-APPLYING MACHINE Oct. 7, 1958 L. M. osBoRNE FLUID-ACTUATED FAsTENER-APPLYING MACHINE Filed Oct. 17. 1955 3 Sheets-Sheet 3 1.14 tislmnlllllllll INVENTOR:

United States Patent O LUID-ACTUATED FASTEN ER-APPLYIN G MACHINE Lloyd M. Qshorne, Burbank, Calif. Application October 17, 1955, Serial No. 540,921

Claims. (Cl. 121-3) This invention relates generally to fastener-applying implements and machines and is concerned more particularly with a duid-actuated device for driving staples and similar fastenersto secure lathing to building studs, roofing material to roof boards, and for various other uses.

Various forms of fluid-actuated, staple-driving hammers and similar implements are currently in use for securing sundry materials and articles together or for fastening different objects against surfaces. Such contrivances usually include a casing having a throat at one end defining a passageway, a staple magazine for containing a supply of staples in stick form, a staple feeding means for'advancing the staples successively from the magazine into the passageway, and a driver blade reciprocable in the casing and adapted, when moved through a working stroke, to shear the leading staple from the stick or refill and drive it through the throat and into the work against which the throat end of the casing of the device is held. The motive power for actuating the driver blade may consist of a piston reciprocable in the cylinder of the casing and to which the driver blade is attached. The casing, or a handle portion thereof, is provided with air passage means through which compressed air is introduced into an end of the casing to act against the piston so as to operate the latter through a working stroke, valve means being employed for controlling the ingress of the air into the cylinder.

In certain machines, the valve and air passage means are so arranged that the compressed air is applied against either side of the piston to selectively actuate the staple driver through working and return strokes, the valve means being of a type permitting exhaust of the air from either end of the cylinder as air is `admitted to the other end thereof. In other similar machines, the piston and staple driver are actuated pneumatically only through the working stroke, a coil spring disposed within one end of the cylinder and engaging the piston being operative to return the piston to its inoperative position and simultaneously expel the air from the other end of the cylinder. In either case, the rate of movement of the piston and driver is dependent upon the permissible rate of discharge of the air from the cylinder through the valve. For this reason, the reciprocatory speed of the driver, and consequently the number of staples driven during a given time, are necessarily limited.

lt has also been determined that where the air is introduced into the end of the cylinder, from which the air was previously exhausted during the return stroke of the piston and driver, the pressure of the compressible air must increase to a value capable of exerting suft`1- cient force against the piston to actuate the latter through its working stroke. Consequently, there exists a certain time lag between the opening of the control valve and the actual start of movement of the piston and driver. Moreover, at the start of the operative stroke of the piston, the movement is relatively slow and as the force 0f the air pressure increases, the movement is gradually ice accelerated. As a result of this condition, instantaneous driving force of maximum amplit'ude is not attained and the impact force of the staple being driven may be such that the staple is not driven completely into the work.

I have determined that in order to drive the staple with the impact necessary to embed its legs lirmly in the work, the driver must be operated rapidly and with considerable driving force. Stated another way, the air must be applied at full pressure against a considerable elective area of the piston, the pressure lirst building up quickly and being suddenly released against the piston t-o actuate the driver rapidly through a working stro-ke. The present improved fastener-applying implement is designed to carry out this highly desirable operation in a practical and etlcient manner.

One object of the present invention is to provide a fluid-actuated, fastener-applying implement or device which is capable of driving fasteners into wood and other materials with suliicient impact to positively embed the staple legs entirely in the work while utilizing a relatively low fluid pressure as the motive power.

Another object of the invention is to provide a fastenerapplying implement, of the character referred to, which embodies a cylinder, a piston slidable in the cylinder, a driver blade carried by the piston and reciprocable in a throat provided at the working end of the cylinder, said driver being operable to successively shear staples from a stick thereof fed intermittently into the throat from a magazine extending normal to the plane of the throat, the implement further including means for applying fluid pressure against the piston to actuate the same through a driving stroke, and means operable to return the piston and the driver to their inoperative positions following each actuation of the device.

In accordance with another important object and feature of the invention, the device or implement is so designed that the actuating piston is subjected to the total fluid pressure instantaneously upon opening of a valve-controlled inlet orice and this effects instantaneous movement of the driver through its operative stroke.

Another object of the invention is to provide a fluidactuated fastener-applying implement which includes a main valve having a head exposed to uid pressure within a chamber at all times, the valve head being of a crosssectional area such that the fluid pressure acting thereagainst normally creates a force of insufficient magnitude upon the valve to activate the piston through its operative stroke. However, when the valve is opened to establish fluid flow from the chamber into the cylinder to impinge against the piston, the entire end area of the piston is subjected to the uid pressure to be propelled rapidly through a fastener-driving stroke.

Another object of the invention is to provide an irnplement of the type indicated in which the upper end of the main lluid chamber is defined by a disc connected to the stem of the main valve to be movable axially downwardly therewith. By this provision, the volumetric capacity of the main chamber is reduced as the valve is opened to join the chamber in uid communication with the upper end of the cylinder, so that loss of fluid pressure through expansion of the chamber, which would temporarily reduce the force applied against the piston, is prevented. As a result of this novel structure, the piston is subjected to a sudden downward thrust to overcome inertia so as to propel the driver downwardly with a positive and rapid action.

Aonther object of the invention is to provide in an implement of the class specied, fluid-actuated means for opening the main valve. According to the present concept, this meanms consists of a valve-actuating plunger slidable vertically in an axial bore in the stem of the main valve element and having a lower, rounded end engageable against a seat or annular shoulder formed at the lower end of the bore. By this means, when the plunger is forced downwardly, its lower end engages the seat or shoulder to force the main valve element downwardly to open the valve. The valve-actuating means also includes an auxiliary piston slidable in the casing and carried at the upper end of the plunger, the space existing between the auxiliary piston and the upper eind of the casing constituting an auxiliary chamber for receiving pressure iiuid from the supply line when a manually-operable control valve is opened. Thus, when the auxiliary piston is subjected to the fluid pressure throughout its large area, it acts through the plunger to unseat the main valve. The area of the auxiliary piston is considerably greater than the area of the valve head exposed to fiuid pressure within the main chamber and as the valve element is initially engaged by the plunger, the forces applied against the plunger by the auxiliary piston and directly against the valve head by the fiuid pressure within the main chamber combine to impart a sudden downward thrust which opens the valve with a rapid action.

Another object of the invention is to provide an implement of the type indicated having means embodied therein by which the air initially introduced into the actuating cylinder to perform a staple-driving operation is exhausted at a rapid rate when the control valve is released, so that instantaneous return of the piston and driver to inoperative position is effected. In accordance with the present concept, this means includes the stem of the main valve and the valve-actuating plunger, the latter being of non-circular cross-sectional shape and defining, with the bore of the valve stem in which it fits, air exhaust passages through which the air may escape from the actuating cylinder into the auxiliary chamber and thence to the atmosphere through an exhaust port provided in the wall of the casing and communicating with the auxiliary chamber.

Another object of the invention is to provide a fluidactuated fastener-applying implement or machine of alternative construction in which a diaphragm is employed in lieu of the disc, said diaphragm having its peripheral portion fixed relative to the casing and its central portion connected to the stem of the main valve. In this modified structure, the diaphragm divides the upper portion into a lower, main chamber in which fiuid pressure is maintained, and an upper, auxiliary chamber into which pressure fluid is introduced through the control valve, flexing of the diaphragm in response to introduction of the fiuid into said auxiliary chamber acting to depress and open the main valve so as to allow passage of the pressure fiuid into the actuating cylinder to actuate the piston and driver through a working stroke. In this alternative implement, a reciprocable, part-tubular plunger is arranged for sliding movement in the bore of the valve stem for engaging an internal seat within the stem, said plunger having a shoulder exposed to the fluid pressure within the auxiliary chamber to effect seating of the plunger. Exhaust of the pressure fluid from the auxiliary chamber creates an unbalanced pressure condition wherein the diaphragm is restored to its unffexed state to close the main valve whereupon the fluid pressure existing within the cylinder unseats the plunger to allow exhausting of the uid through the valve stem and the plunger to the atmosphere by way of an exhaust port provided in the casing, so as to allow return of the piston and driver to inoperative position under the influence of the return spring. i

Another object of the invention is to provide an alternative control valve means which is electrically actuatedV to openand close the fluid inlet and outlet passages leading 1nto and from the auxiliary chamber of the fastener-applying device. In accordance with the invention,

the valve has an actuating solenoid which is energized in response to engagement of a switch-closing plunger against the work into which a fastener is to be driven.

Another object of the invention is to provide a control valve means of further modified structure which is particularly adapted for incorporation in a fastener-applying device of the general character referred to above, said control valve means including a casing structure providing upper and lower compartments separated by an annular seat element engageable by a movable valve member in the form of a ball, the upper compartment being in fluid communication with the main pressure fiuid supply as existing within the main chamber of the implement while the lower compartment is connected to the upper, auxiliary chamber by a fluid passage. A tubular valve-actuating element is slidable in the casing of the device and is adapted, when moved in one direction, to engage and unseat said ball so as to allow passage of the pressure fluid from the supply to the upper compartment, thence through the seat element to the lower compartment and into the auxiliary chamber by way of said fiuid passage. Upon return movement of the actuating pistonV and driver, due to exhausting of the pressure fluid from the cylinder, the iiuid pressure acts against pistonlike heads or anges on the valve-actuating element to move the latter in a reverse direction, this action causing the ball to seat, thus preventing ingress of pressure fluid into the auxiliary chamber but allowing exhaust of the fluid from said auxiliary chamber through the tubular actuating element to the atmosphere. According to the present concept, the tubular actuating element may be slid to valve-opening position by mechanical means, such as a presser foot carried at its lower end and engageable against the work. In another embodiment, the element may be slid by manual means, such as a trigger pivoted to the casing and operatively connected to the element.

Another important object of the invention is to provide an improved control means for use generally in controlling the introduction of pressure uid into a cornpartment, such as an actuating cylinder, said means including a movable valve having a head for opening and closing an orifice leading into said compartment, means for applying fiuid pressure between a fixed area surrounding the orifice and one side of a portion of the valve member of larger pressure area than that of said head so as to normally move the valve member in a direction to seat its head in the orifice, said valve member having a tubular stem, and a plunger slidable in the valve stem and having a pressure area operative, when exposed to fiuid pressure at the other side of said portion of the valve member, to effect movement of the plunger in a direction to cause an end of the plunger to engage a seat within the valve stem to close the latter, fiuid pressure applied against said pressure area of the plunger and against said other side of said portion serving to move the valve member in a direction to open said orifice to admit pressure fiuid into said compartment to perform work, release of fluid pressure from against said other side of said portion and the pressure area of said plunger first allowing unseating of the plunger and then movement of the valve member in a direction to seat its said head under the effect of fluid pressure existing within said compartment, the valve stem and plunger together defining a fiuid exhaust passage through which pressure fiuid can exhaust from the compartment when the plunger is unseated. Thus, the fiuid control means is, in effect, a valve within a valve wherein the inner valve is first seated and the two valves next moved in unison in a first direction to open an orifice, after which the inner valve-is first moved in the opposite direction to unseated position prior to movement of the outer valve in said opposite direction to close said orifice.

Further objects of the invention will appear from the following description and from the drawings which are intended for the purpose of illustration only, and in which: v

Fig. 1 is a vertical sectional view through one form of the fluid-actuated, fastener-driving implement;

Fig. 2 is a plan view of the valve member taken on line 2-2 of Fig. 1;

Figs. 3, 4 and 5 are Small-scale views, similar to Fig. 1, showing7 the relation of the piston-actuating means during successive stages of the staple-driving operation, these views of being of a more or less diagrammatic nature; v

Fig. 6 is a view similar to Fig. 1, illustrating a fastener-applying implement of a modified form;

Figs. 7 and 8 are cross-sectional views, taken respectively on lines 7-7 and 8 8 of Fig. 6;

Fig. 9 is a view similar to Fig. l, showing a further alternative construction of the device;

Fig. 10 is a vertical sectional view, taken on line 10-10 of Fig. 9; f

Fig. 11 is a cross-sectional View, taken on line 11-11 of Fig. 9; and

Fig. 12 is a fragmentary, vertical sectional View of a portion of the implement illustraed in Fig. 9, showing an alternative means for actuating the control valve.

The Huid-actuated, fastener-applying mechanism of the present invention is adapted for hydraulic or pneumatic operation. Consequently, the terms pneumatic, airactuated, air-pressure etc., as employed in the following description are to be construed as covering broadly a Huid-actuated means and motive fluid, whether the latter be of a liquid or gaseous nature. In addition, while the device as disclosed herein is designed for driving staples into the work, it will be apparent that the mechanism may be so constructed that it may apply fasteners of other types, the term staple therefore being used in a general sense to cover all fasteners capable of being driven into the work. As will be later noted, while the fastener-applying means covered by the present invention is herein illustrated as embodied in a portable implement or tool, such means may be incorporated in a more or less stationary machine and the terms implement, device and tooL are intended to include such machines.

Referring rst to Figs. 1 to 5, the fastener-applying implement of this invention may take substantially the form therein illustrated. In this typical example, the implement includes a vertical casing 20 which comprises lower and upper tubular sections 21 and 22 welded together as indicated at 24 and an annular partition or valve seat element 23 is interposed therebetween. The upper end of the top section 22 is closed by an upper cap or end plate 25, secured in place by screws 26. In a similar manner, the lower end of the bottom section 21 is closed by a lower cap or end plate 27 fastened in place by screws 2S. This lower end plate 27 has a depending projection 30 which provides a throat through which staples are driven into the work by means to be later described in detail, the cap 27 and its throat portion 36 having a vertical groove 31 of rectangular cross-section, the length and width of this groove being substantially equal to the length and thickness of the cross-bar of a staple S to be driven through the throat. The rearward side of the throat portion 30 is recessed at 32 to receive the forward end of a staple magazine 33 having an elongated bar or core 34 along which the stick of staples S is advanced into the throat by means of a conventional, spring-actuated staple pusher 35. The forward end of the magazine 33 may be attached to the throat by means of screws 36.

Suitably fastened against a side of the upper casing section 22 is a handle or hand grip 40 by which the implement can be supported in a hand of the person operating the same, a sealing pad 41 being interposed between the casing and the handle to provide an air-tight joint.

The seat element 23 is provided with a central opening or orice 44 which, as shown is tapered to provide a valve seat. A valve member 45 of the tappet type has a tapered head 46 adapted to seat upwardly against the valve seat 44. The member 45 has an upwardly directed, tubular stem 47 having a reduced portion providing an annular shoulder 48 against which a movable partition disc 49 is held by means of a nut 50 screwed onto the upper threaded extremity of the stern. The valve member 45 is adapted to slide vertically within the upper casing section 22, downward movement of the member being limited by engagement of the movable disc 49 against an annular shoulder 51 within the upper section. An G-ring 52 is tted within a peripheral groove in the disc 49. It is to be observed that the valve member 4S has an axial bore 53 of circular lcross-sectional shape (Fig. 2). The lower end of the valve member 45 is ilared inwardly at the bore 53 to provide a seat 55 for a plunger 56 which, as shown in Fig. 2, is of non-circular cross-sectional shape, for example, square. The plunger 56 has an upper reduced end 57 upon which an auxiliary piston 58 is held, this piston carrying an O-ring 59 at its periphery.

The' disc 49 and auxiliary piston 58 divide the upper portion of the casing 20 into a main air chamber 60 between the valve seat element 23 and the disc 49, an air exhaust chamber 61 between the disc 49 and the auxiliary piston 58, and an auxiliary cylinder 62 between the piston 58 and the upper end cap 25. The internal area of the casing 20 between the valve seat element 23 and the lower end cap 27 constitutes a main air cylinder 63. A first air inlet port 66 is provided in the wall of the upper casing section 22 and communicates with the air chamber 60. A second air inlet port 67 is likewise provided in said wall, this port communicating with the auxiliary or secondary cylinder 62. An air exhaust port 68, also in the wall, is employed for directing air from the auxiliary chamber 61 to the atmosphere.

The hand grip 40 is provided with a main air inlet passage 70 for receiving air from a compressed air tank,

through a hose 71. The passage 70 leads to a bore 72 in whicha valve casing 73 is disposed. A rst air passage branch 74 extends from the bore 72 to the air inlet port 66, thus bypassing the valve casing so that when pressure air is supplied to the main passage 70, the main chamber 6d is charged with the same.

A valve element 75 is slidable within the casing 73 and normally is urged upwardly by means of a coil spring 76 engaging against an actuating button 77 at the upper end of the element. Air enters the lower end of the valve casing 73 through a hole 78. The valve element '75 has an L-shaped passage 79 which, when the element is depressed, aligns with a hole 80 in the wall of the casing 73, the hole S0 communicating with a second air passage branch S1 leading to the secondary air inlet port 67 so as to cause the pressure air to enter the secondary cylinder 62. When the valve element '75 is released to be projected upwardly by the spring 76, a groove 83 in its periphery provides a flow passage between the hole 80 and a second hole 84 connected to an air exhaust passage 85' provided in the hand grip 40 and leading to the atmosphere.

Slidable in the main cylinder 63 is a main actuating piston which carries a staple-driver blade 91 which is slidable in the throat 31, the piston having an O-type sealing ring 92 engageable with the wall of the cylinder. A coil spring 93 having its end portions engaging in recesses in the piston 90 and end cap 27 normally is operative to force the piston upwardly to its inoperative position.

Assuming that the parts of the staple-driving implement are in the positions illustrated in Figs. 1 and 3, pressure air is present in the chamber 60. This pressure acts` between the seat element 23 and the disc 49 of the valve member 45 to normally maintain the latter in its upper position, the effective area of the head 46 exposed to the air pressure being relatively small. Since the valve element 75 is in its upper position, flow of pressure air from the passage 70 to the secondary cylinder 62 is prevented and the implement thus is inactive. With the lower end of the driver 91 located above the core 34, the staple pusher 35 urges the stick of staples S forwardly to locate the leading staple within the throat, directly below the driver 91. i

To apply a staple S to the work, the operator holds the implement by the hand grip 40 and places the lower end of the throat element 30 against the work. The valve element 75 is next depressed to align its flow passage 79 with the hole 80, passage 81 and inlet port 67 so as to cause introduction of the pressure air into the secondary or auxiliary cylinder 62. The air, acting between the cap 25 and piston 58, propels the latter downwardly. Thus, the plunger 56 is forced downwardly to cause its lower rounded end to engage the seat 55 so as to close the bore 53. The combined fluid pressure forces acting against the piston S and against the valve head 46 is sufficient to unseat the valve head (Fig. 4) to effect rapid ow of the pressure uid from the chamber 60 into the cylinder 63. At this instant, the air pressure within the chamber 60 is applied against the full area of the main piston 90. This force is suliicient to overpower the spring 93 and propel the main piston 90 downwardly at a very fast rate of movement. Thus, the driver 91 is caused to shear the leading staple S from the strip and drive it through the throat 31 and into the work with great impact. Movement of the valve head 46 to open position is limited by engagement of the disc 49 against the shoulder 51.

When the valve button 77 is released following the driving of a staple, the valve element 75 returns to the position shown in Fig. l so that the air within the secondary cylinder 62 exhausts to the atmosphere by way of the port 67, passage 81, hole 80, groove S3, hole 84 and passage S5. Such exhaust of air allows upward movement of the secondary piston 58 and this is immediately affected to cause the air to be exhausted from the secondary cylinder due to the uid pressure within the main cylinder 63 acting against the lower end of the plunger 56 exposed thereto (Fig. 5). Since the piston 5S no longer functions to force the valve member 45 downwardly, the liuid pressure within the chamber 60, acting between the partition 23 and the disc 49 now restores the valve member 45 to its initial position to close the orifice 44, this action being augmented by uid pressure within the main cylinder 63 acting upwardly against the valve head 46. Referring again to Figure 5, it, will be noted that the valve 46 is first closed and thereafter further compression of the air above the piston 90 causes the plunger 56 to become unseated. This, in turn, raises the piston 58 to the position shown in Figure l. Upon unseating of the plunger 56, the pressure fluid within the main cylinder 63 is caused to exhaust through. the passages defined between the cylindrical bore 53 and the at sides of the plunger 56. The fluid exhausts into the chamber 61 and thence to the atmosphere through the port 68. While such exhausting of the uid is relatively fast to effect quick return of the piston 90, this action is cushioned by the fluid exhausting from the auxiliary cylinder 62. Consequently, recoil of the implement is practically nil.

It will be observed from the above that the driving action of the piston 90, as effected by the application of pressure air thereagainst, is very rapid so that the staple is driven with great impact and its legs are fully embedded in the work. Due to theV large effective areas involved, air of relatively low pressure can be utilized to operate the valve 45 and piston 90. Also, because of the rapid response of the parts to actuation of the control valve 75, the implement can be operated in rapid succession to apply the staples, the rate of such application of the staples to the work being limited onlyY by the ability of the operator to actuatenthe control valve 75. It is also to be noted that the d evice can be operated in any position so that it is adapted for'uise in fastening lathe or sheet material to/verti'cal, as well ashorizontal, building surfaces.

Referring now to Figs. 6 to 8 of the drawings, the present invention also contemplates an implement of alternative structure.` This modified device includes a cylindrical casing 100, to the upper and lower ends of which are applied end caps 101 and 102. Substantially midway between its ends, the cylinder carries a cup-shaped element 103, the lower, transverse end portion 104 of which provides a partition or valve seat portion, a segmental orifice 105 in the partition having a tapered portion providing a valve seat 106.

Disposed within theiupper end of the casing 100 is a sleeve 107. Interposed between this sleeve and the upper end of the element 103 is the peripheral portion of a diaphragm 110. As shown, the central portion of the diaphragm is held between a pair of rings 111 retained against a peripheral shoulder 112 on the tubular valve stem 113 of a valve member 114, a clamping ring 115 on the stem holding the rings 111 in place. At its lower end, the valve member 114 has a tappet-like valve head 116 engageable against the seat 106. The valve stem 113 has a bore 117 which is enlarged intermediate the upper and lower ends of the member 114, thus providing a conical valve seat 118.

A plunger 120 has an enlarged flange portion 121 slidable in the upper end portion of the stem 113, this flange carrying an 0-ring 122 for sealing between the flange and the bore of the stem. Below the ange 121, the plunger 120 is of less diameter than the upper end of the bore in the stern, thus providing an air exhaust passage 125. The plunger 120 has an axial bore 126 which terminates above the lower end of the plunger. A transverse hole 127 in the plunger 120 establishes fluid communication between the interior of the stem 113 and the bore 126. The upper end of the plunger 120 is Slidable in a vertical hole 12S formed in the upper end cap 101. A radial air exhaust passage or port 129 communicates between the hole 12S and the atmosphere. An O-ring 130 seals the clearance between the hole 128 and the plunger 120.

The valve seat portion 104, diaphragm 110, end caps 101 and 102 define, with the walls of the casing 100, an actuating cylinder 131, an air chamber 132 and an auxiliary or secondary air cylinder 133.

Slidable in the cylinder 131 is a main piston 135, normally urged upwardly to the position shown in Fig. 6 by means of the spring 136. Fluid pressure could be employed in lieu of the spring 136. As in the previouslydescribed embodiment, the piston 135 carries a staple driver blade 138 which is Slidable in a vertical staple groove formed in the throat portion 139 of the lower end cap 102, into which the staples S are fed successively into position beneath the driver.

A handle or hand grip 142 is secured against a side of the upper portion of the casing 100 and has an air inlet passage 143 to which pressure air is supplied by an air hose 144 connected to a suitable source of compressed air. The passage 143 leads to a bore 145, the air then passing through a branch passage 146 and an inlet port 147 into the chamber 132.

A control valve 150 has a casing or sleeve 151 forced into the bore 145, the sleeve having a hole 152 in its lower closed end and a transverse hole 153 thereabove. A plunger 155 is Slidable in the sleeve 151 and has a peripheral groove 156 and an L-shaped air passage 157. A coil spring 158 normally maintains the plunger in its raised, valve-closing position. At one side of the sleeve 151, the hole 153 is in fluid communication with the secondary cylinder 133 by reason of a branch passage 159 and air inlet port 160. At the other side of the sleeve 9 151, the hole 153 communicates with the atmosphere by way of an airexhaust passage 161.

The control valve plunger 155 normally is held in the position illustrated in Fig. 6 to effect exhaust of air from the cylinder 133, by reason of the spring 158. A solenoid 163 is operative, when energized, to depress the valve plunger 155 so as to align the passage 157 thereof with the branch passage 159 and thus connect the cylinder 133 to the source of compressed air.

The solenoid 163 is connected in an electrical circuit including the wires 164 and 165 adapted for connection to a service outlet. Connected in series with the solenoid 163 are spring contact elements 166 and 167 mounted, by means of dielectric discs 168, within a recess in the lower end cap 102, the contact elements being of U-shape to extend around the driver 138 (Fig. 8). Slidable in a vertical hole 169 in the throat 139 is an actuator pin or presser rod 170, the lower end of which normally projects downwardly below the throat to engage the work into which a staple is to be driven. The upper end of the rod 170 is positioned to engage the lower contact element 167.

When it is desired to drive a staple, the implement is placed such that the throat extension engages the work. The presser rod A170 thus is forced upwardly to tlex the contact element 167 against the contact element 166 to close the circuit to the solenoid 163 so as to energize the latter. As a result of such energization, the control valve plunger 155 is depressed to establish flow of pressure air from the passage 143, through the hole 152, passage 157, hole 153, branch passage 159and inlet port 160 into the cylinder 133. Pressure air thus introduced into the secondary cylinder 133 rst acts against the exposed end of the ange 121 of the plunger 120 to force the lower end of the latter into engagement with the conical seat 118. The diaphragm 110 then is ilexed downwardly, as indicated by the broken lines in Fig. 6, so as to force the valve member downwardly. With the valve 116 thus unseated, the pressure air flows rapidly from the chamber 132 into the main cylinder to be applied directly against the full pressure area of the piston 135 so as to propel the latter and driver 138 downwardly to shear the leading staple S from the strip or stick and drive the same into the work.

Following the driving of the staple into the work, pressure of the implement against the work is relieved to allow projection of the presser rod 170 under the spring tension of the contact element 167. This action eifects separation of the contact elements so as to open the circuit to the solenoid to deenergize the latter, whereupon the spring 158 raises the valve plunger 155 to disalign the passages 157 and 159 and align the exhaust groove 156 with the transverse hole 153. By this action, the cylinder 133 is connected to the exhaust passage and atmosphere so as to allow exhaust of air from this cylinder. The fluid pressure within the actuating cylinder is then applied against the lower end of the plunger 120 to raise the latter from the conical seat 118. Unseating of the plunger 120 establishes air flow from the main cylinder 131 to atmosphere by way of the hole 27, bore 126 and passage 129. Simultaneously, the pressure within the chamber 132 is exerted against the diaphragm 110 to move the valve member 114 into position to seat its head 116. The piston 135 comes to rest adjacent the valve head 116 to locate the lower end of the driver 170 above the plane of the staple stick to allow advancement of another staple into the groove 169 in position to be subsequently driven.

Referring now to Figs. 9 to l2, the instant invention further contemplates a modified fastener-applying device in which the control valve means is actuated mechanically in response to engagement of the device against the work. This modiled structure includes a cylindrical casing 200, the upper and lower ends of which are closed by end caps 201 and 202. The casing 200 has a partition 203 provided with a central hole or valve orice 204.

The casing 200 is formed with a hollow handle or hand grip 205, the interior of which receives pressure air from a source through the medium of a hose 206.

A tappet-type valve member 210 is slidable within the upper end of the casing 200 and has a conical head 211 at its lower end engageable within the orifice 204 to close the same. The valve member 210 hasa bore 212 which is enlarged intermediate its ends, thus providing a conical valve seat 213. The member 210 has a piston portion 215 slidable in a bore 216 in the upper end cap 201, downward sliding movement of the member being limited by a stop ring 217. The end caps 201 and 202, the partition 203 and secondary piston 215 define with the casing 200 a main actuating cylinder 220, an air cham ber 221 and a secondary or auxiliary cylinder 222.

A main piston 225 is slidable in the main cylinder 220 and carries the staple driver 226. A spring 227 nor mally is operable to maintain the piston and driver in the elevated position shown in Fig. 9.

An air inlet port 229 in the casing 220 connects the air chamber 221 with the interior of the handle 20S. The upper end cap 201 is provided with an air exhaust port 228.

Slidable in the upper end of the valve member 210 is a plunger 235 having an annular shoulder 236 exposed within the auxiliary cylinder 222. The upper end of this plunger is slidable in a hole 237 in the end cap 201. The plunger 235 has a conical lower end 238 engageable with seat 213. The plunger has a bore 239 terminating above its lower conical end, and a transverse hole 240, the interior of the valve member 210 thus being in communication with the atmosphere by way of the hole 240, bore 239 and passage 228.

The device of Figs. 9 to 12 embodies a novel and ingenious control valve means which is constructed and arranged as next described.. As shown in Fig. 9, the upper end cap 201 is provided with a lateral extension 245 formed with an air chamber 246. Below the chamber 246, the casing 200 has three vertically aligned bosses 248, 249 and 250. The upper boss 248 has a bore 252 and a compartment 253 arranged directly below the chamber 246. A sleeve or seat element 255 is located within the compartment 253 and has an orifice 256 communicating with theV chamber 246 and compartment 253. A valving element, in the form of a ball 25S is disposed within the chamber 246 and normally rests upon the sleeve 255 to seal the orice 256 against passage of air from the chamber 246 to the compartment 253. A tirst air passage 262 in the boss 248 extends between the chamber 221 and the valve chamber 246. A second air passage 263 extends between the compartment 253 and the auxiliary cylinder 222 (Figs. 9 and ll).

A combined valve-actuating and air-exhaust tube 265 is slidable vertically in the bosses 248, 249 and 250, the upper end of this tube being located within the compartment 253, directly below thc ball 258. As shown in Figs. 9 and l0, the tube 265 has piston- like heads 267 and 268 which are slidable respectively in the bore 252 in the boss 243 and a bearing hole 269 in the boss 249. These heads have O-ring seals 270. The boss 249 has an annular shoulder 271 against which the head 268 engages to limit the downward sliding movement of the tube 265.

Carried at the lower end of the tube 265 is a sleeve 273 which has a bore 274 provided with a closed lower end. A transverse hole 275 in the tube communicates between the bore 274 and atmosphere. Fitted within a slot 276 in the lower end of the sleeve 273 is the upper end of a valve-actuating element or bar 278. As shown in Fig. 10, the bar 278 has a lateral extension or foot 279 which extends beneath the staple magazine 230 at a level slightly below the lower end of the throat extension 281 of the lower cap 202, in position to engage against the work into which a staple is to be driven.

With the implement connected to the source of compressed air and with the parts in the positions illustrated in Fig. 9, thev implement is ready for use. To drive a staple S into the work, the implement is held in a hand of the operator by means of the hand grip 205. It will be apparent that at this time air pressure exists within the hand grip, in the inlet port 229 and the chamber 2214. Such pressure is also present in the passage 262 and valve chamber 246.

To drive a staple, the throat portion 281 is directed toward the work and during this movement the presser foot 279 is engaged against the work to force the sleeve 273 and tube 265 upwardly as shown in Fig. l0. During this action, the upper end of the tube 265 engages and lifts the ball 253 from the seat 255 to first seal the exhaust tube 265, whereupon the pressure air in the valve chamber 246 flows rapidly into the compartment 253 and passage 263 and thence into the auxiliary cylinder 222 to act against the shoulder 236 of the plunger 235 to depress the latter into engagement with the conical seat 213 so as to close the bore 212 of the valve member 210. Simultaneously, the piston 215 is subjected to the air pressure. The effective areas of the piston 215 and the valve head 211 exposed to the fluid pressure are such that the valve member 210 is depressed rapidly so as to open the orifice 204. Thus, pressure air is admitted to the upper end of the main cylinder 220 to act against the upper end area of the piston 225 so as to rapidly propel the piston and staple driver downwardly and thus drive a staple S through the throat and into the work. The piston 225 preferably carries a resilient bumper pad 283 for cushioning the impact of the piston against the lower end cap 202. Downward movement of the valve member 210 is limited by engagement of the auxiliary piston 215 against the stop ring 217.

After the staple has been applied to the work, manual force of the implement against the work is relieved to allow the valve-operating bar to descend. This latter action is effected by reason of the air pressure within the chamber 246 acting against the ball 258 to depress the tube 265. The compartment 253 thus is sealed from the pressure chamber 246. At this juncture, the air pressure existing within the cylinder 222, passage 263 and compartment 253 acts against the head 267 to forcibly slide the tube 265 downwardly until the head 263 engages the stop shoulder 271. The air within the cylnder 222 thus may exhaust to the atmosphere by way of the tube 265 and holes 275.

With the valve member 216 thus free to slide upwardly, the pressure air within the upper end of the main cylinder 220 exerts an upward thrust against the lower end of the plunger 23S to raise the latter relative to the valve member 21?. With the plunger 235 thus unseated, the air passes into the valve member 210 and thence exhausts through the hole 240 and bore 239 to the atmosphere by way of the exhaust port 22S. Fluid pressure within the chamber 221, acting against the piston 215, restores the valve member 210 to initial position to seal the orifice 204. The main piston 225 and the staple driver 226 connected thereto return upwardly to inoperative position under the influence of the spring 227. Such upward movement of the piston 225 is limited by engagement of the piston against a stop ring 285. Return movement of the plunger 235 is limited by engagement thereof against the bottom of the hole 237 in the end cap 201. Such return of the parts to initial position is automatic, as heretofore explained in connection with the structure of Figures l and 4.

lt is within the concept of the instant invention to actuate the valve means 265, 258 manually by means of the trigger finger 362i? shown in Fig. 12. The operating 'finger 350 has a forked end 301 pivoted on a pin 502 held in a lug 393 forming part of the casing 200. The trigger 399 has slots in the sides of the forked end for receiving pin 305 carried by the sleeve 273. As

12 will be apparent, upward pivotal movement of the trigger effects upward sliding movement of the tube 265 to unseat the ball 258 and to close the exhaust tube.

It will be observed from the foregoing that the present invention provides a fastener-applying implement or machine which is fluid actuated and which is positive and extremely rapid in operation. Unlike other fluid-'actuated devices of this general type, the pressure fluid is introduced into the actuating cylinder in response to actuation of a valve member which normally is in position to close a fluid orifice leading to the actuating cylinder. As a feature of improvement, the lvalve member normally is maintained seated in response to fluid pressure present in a chamber of the device at all times, this pressure acting between a fixed area within the casing and a disc, diaphragm or other part operatively connected to the valve member and having a pressure area considerably larger than that of the head of the valve member, fluid pressure exerted against the head and said part being sufficient to open the valve member to admit pressure fluid into the actuating cylinder. According to the invention, the valve member has a fluid exhaust passage thereinthis passage being closed prior to actuation of the valve member to its open position, the means for closing the exhaust passage being in the nature of a plunger having a first end adapted to engage a seat within the exhaust passage to seal the latter, and a second end adapted to be exposed to the full fluid pressure to move the plunger to passage-closing position. By this arrangement of parts, when fluid pressure against the said part of the valve member and plunger and this fluid a1- lowed to exhaust from the casing, the pressure fluid previ-V ously introduced into the actuating cylinder acts to unseat the plunger to open the fluid exhaust passage through the valve member so as to allow rapid exhausting of the fluid from the cylinder. Since the valve member meets no resistance to its return movement to orificeclosing position, the pressure fluid continuously applied against its said disc or other part restores the valve member automatically to initial position to close said orifice. It is thus seen that the double valve means for controlling introduction of pressure fluid into, and exhausting of the same from, the actuating cylinder functions to first close the exhaust passage and then actuate the valve member to open position so as to inject the pressure fluid into the cylinder; and following actuation of the device through a working stroke the exhaust passage is first opened and the valve member then moved to closed position, this being a feature which produces a new and unexpected result not attainable by the use of conven-A tional controls wherein the exhaust passage is opened following closing of the valve member.

As another feature of improvement, in the present device the exhaust passage of the valve member is opened during exhausting of the pressure fluid employed to seat the plunger and open the valve member. Consequently, the exhausting head of fluid serves as a cushion or buffer to absorb shock so that recoil of the device is avoided. The device thus may be operated in rapid succession without undue shock, to drive the fasteners firmly into the work. Also, due to the relatively large effective pressure areas involved, fluid pressure of lower value than heretofore employed in similar devices may be utilized to advantage.

The device has been herein described as of a portable hand ty-pe but it will be apparent that the mechanism may be embodied in a stationary machine, in which case the hand grip may be dispensed with and the control valve means and inlet, outlet fluid passages incorporated in the machine housing or in fluid lines leading to and from the various chambers. It is also within the present concept to utilize fluid pressure, in lieu of the return spring, for returning the main piston to inoperative position in which case the pressure fluid will be introduced into and exhausted from, the lower end of the actuating 13 cylinder in timed sequence with the valve member and other elements. The invention -further contemplates a device or machine in which the driver, throat and other parts are designed with a view toward driving nails or the like into the work.

In accordance with the provisions of the patent statutes, I have herein described the principle of the invention, together with several forms of construction of the device. It will be apparent, however, that Various modifications might be made in the structure, without departing from the spirit or scope of the invention, as defined in the appended claims.

l claim as my invention:

1. In a fluid-actuated fastener-applying device, a closed, hollow casing lhaving a throat at one end, a partition in said `casing having a valve orifice; a piston reciprocable in said casing between said partition and said throat; a fastener-driver blade carried by `said piston, a valve member having a head at the side of said partition adjacent said piston for seating in said orifice; a first fluid pressure means normally operative to maintain said head so seated; plunger means movable in said casing and engageable with said valve member; a second fluid pressure means operable to move said plunger means in a direction to engage said valve member and unseat said valve head; control valve means associated with said second fluid pressure means for controlling application of fluid pressure against said plunger means, unseating of said valve head effecting application of the first pressure fluid against said piston to actuate the latter through a working stroke, inactivation of said second fluid pressure means allowing seating of said valve head; and means for applying a force against said, piston to return the same to inoperative position adjacent said partition.

2. In a fluid-actuated fastener-applying device, a closed hollow casing having a throat at one end, a partition in said casing having a valve orifice; a piston reciprocable in said casing between said partition and said throat, a fastener-driver blade carried by said piston, a valve member having a head at the side of said partition adjacent said piston for seating in said orifice; a first fluid pressure means normally operative to maintain said head so seated; plunger means movable in said casing and engageable with said valve member; auxiliary means having a sealing engagement with and movable relative to the end 'of said casing opposite to its said throat end, said means being operatively connected to said valve member and having a fluid pressure area in excess of the fluid pressure area of said valve head; a second fluid pressure means operable to move said auxiliary means and said plunger means in a direction to unseat said valve head; control means associated with said second fluid pressure means for controlling application of fluid pressure against said auxiliary means and said plunger means, unseating of said valve head effecting application of the first pressure fluid against said piston to actuate the latter through a working stroke, inactivation of said second fluid pressure means allowing seating of said valve head; and means for applying a force against said piston to return the same to inoperative position adjacent said partition.

3. In a fluid-actuated fastener-applying device, a closed, hollow casing having a throat at one end; partition means in said casing and provided with an orifice, the portion of the casing at one side of the partition means constituting a main actuating cylinder anda portion of the casing at the other side thereof providing a fluid chamber; a piston reciprocable in said main cylinder and carrying a fastener-driver movable in said throat; fluid' passage means for introducing pressure fluid into said chamber and continuously maintaining fluid pressure therein; a valve member movable axially in said chamber and having a valve head, said head being disposed in said main cylinder and normally urged into said orifice to close the same under the influence of the pressure fluidV in said chamber, force of the fluid pressure in said chamber 14 t acting against the area of said valve head exposed thereto in said orifice being insuflicient to unseat said valve head; valve-actuating plunger means within said casing engageable against said valve member and having a portion adapted to be exposed to fluid pressure; fluid passage means for applying fluid pressure against said portion so as to cause said plunger means to actuate said valve member in a direction to unseat its said head and allow flow of the pressure fluid from said chamber into said main cylinder, pressure fluid then applied against the end area of the piston exposed thereto actuating the piston through an operative stroke; control valve means selectively operative to effect application of the pressure fluid against said portion of said plunger means to actuate the same and to effect exhaust of said pressure fluid following such actuation; exhaust passage means embodied in said valve member, plunger means and said casing byrwhich the pressure fluid in said main cylinder can exhaust to atmosphere in response to return movement of said main piston; and means for applying a force against said piston to return the same to inoperative position adjacent said partition.

4. In a fluid-actuated fastener-applying device, a closed, hollow casing having a throat at one end, partition means in said casing and provided with an orifice, the portion of the casing at one side of the partitionmeans constituting a main actuating cylinder and a portion of the casing at the other side thereof providing a fluid chamber; a piston reciprocable in said main cylinder and carrying a fastener-driver movable in said throat; fluid passage means by which pressure fluid is introduced into and continuously maintained within said chamber; a valve member movable axially in said chamber and having a valve head disposed in said main cylinder, the fluid pressure in said chamber normally urging said valve member in a direction to maintain its said head in said orifice to close the same, force of the fluid pressure in said chamber acting against the area of said valve head exposed thereto in said orifice being insuicient to unseat said valve head; Valve-actuating plunger means within said casing engageable against said valve member and having a portion adapted to be exposed to fluid pressure;

fluid passage means for applying fluid pressure against.

said portion so as to cause said plunger means to actuate said valve member in a direction to unseat its said head and allow flow of the pressure fluid from said chamber into said main cylinder, pressure fluid then applied against the end area of the piston exposed thereto actuating the piston through an operative stroke; control valve means selectively operative to effect application of the pressure fluid against said portion of said plunger means to actuate the same and to effect exhaust of said pressure fluid following such actuation; exhaust passage means embodied in said valve member, plunger means and said casing by which the pressure fluid in said main cylinder can exhaust to atmosphere in response to return movement of said main piston; and means for applying a force against said piston to return the same to inoperative position adjacent said partition means.

5. In a fluid-actuated fastener-applying device, a closed, hollow casing having a throat at one end, partition means in said casing and provided with an orifice, the portion of the casing at one side of the partition means constituting a main actuating cylinder and a portion of the casing at the other side thereof providing a fluid chamber; a piston'reciprocable in said main cylinder and carrying a fastener-driverrmovable in said throat; fluid passage means by which pressure fluid is introduced into and continuously maintained within said chamber; a valve member movable axially in said chamber and having a valve head disposed in said main cylinder; fluid pressure-actuated means normally operative to urge said valve member in a direction to maintain its said head across said orifice to close the same, force of the fluid pressure in said chamber acting against the area of said valve head exposed thereto in said orice being insufficient to unseat said valve head; valve-actuating plunger means Within said casing engageable against said valve member and having a portion adapted to be exposed to fluid pressure; Huid passage means for applying uid pressure against said portion so as to cause said plunger means to actuate said valve member in a direction to unseat its said head and allow llow of the pressure Huid from said chamber into said main cylinder, pressure uid then applied against the end area of the piston exposed thereto actuating the piston through an operative stroke; control valve means selectively operative to etect application of the pressure fluid against said portion of said plunger means to actuate the same and to effect exhaust of said pressure fluid following such actuation, said valve member having an axial bore and an internal shoulder engageable by said plunger means to rst close said bore and thereafter move said valve member to valve-opening position, relief of uid pressure from against said portion of said plunger means allowing movement of said plunger means from 15 said shoulder under the influence of the pressure fluid in said main cylinder acting thereagainst so as to allow exhaust of said pressure fluid from said main cylinder through said bore, said casing having an exhaust port communicating with said bore, and to allow return of said valve member to initial position under the influence of the fluid pressure within said chamber; and means for applying a force against said piston to return the same to inoperative position adjacent said partition means.

References Cited in the le of this patent UNITED STATES PATENTS 2,320,340 Appton June l, 1943 15 2,338,127 McAndrews Ian. 4, 1944 2,400,330 Allen May 14, 1946 2,459,456 Rockwell -,l Jan. 18, 1949 2,585,939 Juilfs Feb. 19, 1952 2,585,940 Iuilfs Feb. 19, 1952 20 2,729,198 FacCOu Ian. 3, 1956

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