US2629582A - Hydraulic lift mechanism - Google Patents

Description

Feb. 24, 1953 J. o. STEPHENSON ET AL HYDRAULIC LIFT MECHANISM 4 Sheets-Sheet 1 Filed Oct. 15, 1948 3m entor JOHN O. STEPENSON JOHN H. HILLIS- 8 K Gttomeg Feb. 24, 1953 J. o. STEPHENSON ET AL 2,629,582

' HYDRAULIC LIFT MECHANISM Filed Oct. 15, 1948 4 Sheets-Sheet 2 FIG 4 ll Ill 7| FIG. 5

U/ 3110mm w E H JOHN 0. STEPHENSON ea O JOHN H.H|LL|S m Bu mun mm W 67 Gttorneg Feb. 1953 1. o. STEPHENSON ET AL 2,629,582

HYDRAULIC LIFT MECHANISM I Filed Oct. 15, 1948 4 Sheets-$h66t 3 73 88 72 96 us 75 l 7| 7 so 96 K u 3 j ll n2 F/ G. 8 as y 67 V E v Snventor AB /E] 93 JOHN o. STEPHENSON 9\ 97 JOHN H. HILLIS 109 11 H6 Bu M Fl 7 I Gtorneg Feb. 24, 1953 J. o. STEPHENSON ET AL HYDRAULIC LIFT MECHANISM F iled Oct. 15, 1948 4 Sheets-Sheet 4 3maentor JOHN O. STEPHENSON JOHN H. HI

L L I S B}; v

l (Ittorneg Patented Feb. 24, 1953 HYDRAULIC LIFT MECHANISM John 0. Stephenson and John H. Hillis, Detroit, Mich.; said Hillis assignor to said Stephenson Application October 15, 1948, Serial No. 54,684

Claims.

This invention relates in general to a hydraulic lift mechanism and more specifically to a type thereof having a foot actuated hydraulic pump and an adjustable gripping device for engaging and supporting parts of a motor vehicle.

It has been observed by persons familiar with the repair of motor vehicles that the removal of certain parts of said vehicles, such as hydraulic, or other heavy, transmissions and heavy differentials, requires expensive, complicated equipment and at least two workmen. Furthermore, in order to use such present types of equipment for removing said parts, it is often necessary to disassemble other portions of the vehicle, which have nothing to do with the part to be removed, in order to gain working access to the said part.

Further, with present equipment it often happens that a workman can, or must, place part or all of his body underneath the part being handled during the adjustment thereof, and since these parts occasionally slip from their supporting means the danger of injury to the workman and to the part is material.

Therefore, the need becomes apparent for a means whereby such cumbersome parts may be easily and safely removed from a vehicle by one workman, and by which he may do so without dismantling other non-associated portions of the vehicle to gain working access to said part.

Accordingly, a principal object of this invention is the provision of a hydraulic lift mechanism having a movable, adjustable gripping means for engaging and supporting certain cumbersome parts, such as hydraulic, or other heavy, transmissions and heavy differentials, of a motor vehicle.

A further object of this invention is the provision of a hydraulic lift mechanism as aforesaid by means of which one workman can easily and safely remove said cumbersome parts from a vehicle without dismantling other portions of said vehicle in order to gain working access to said cumbersome parts and without danger of injury either to the part or to himself.

A further object of this invention is the provision of a means for removing said cumbersome parts more easily and safely than said complicated equipment presently in use, and which means is far less expensive to manufacture and use.

Other objects and purposes of this invention will become apparent to persons familiar with this type of equipment upon referring to the accompanying drawings and upon reading the following specification.

In meeting those objects and purposes mentioned above as well as others incidental thereto and associated therewith, I have provided a hydraulically actuated lift mechanism comprised of a hydraulic lifting element having a long narrow chassis which is supported at both ends by appropriate wheeled means, and to one end of which is attached a suitable handle. A cantilever lift arm, which is pivotally supported at one of its ends upon said chassis, is provided at its other end with a removable, adjustable gripping means which is automatically held upright throughout all positions of normal operation. Said lift arm is raised by means of a hydraulic cylinder extending between said lift arm and said chassis. A hydraulic pump for actuating said cylinder is connected thereto by a flexible hose and may be removably supported within said handle during transport of the device.

For convenience in description, the lifting device is disclosed in connection with a hydraulic transmission but it will be understood that it may also be used with other heavy parts, including differentials and mechanical transmiss1ons.

For one preferred embodiment of the invention, attention is directed to the drawings in which:

Figure 1 is a side elevation view of the hydraulic lift mechanism and pump to which this invention relates.

Figure 2 is a broken, top plan view of the hydraulic jack and pump.

Figure 3 is a fragmentary, sectional View of Figure 2 without the hydraulic pump.

Figure 4 is a sectional view of the hydraulic cylinder shown in Figure 3 taken along the line IV-IV.

Figure 5 is a side-elevation view of the hydraulicpump with the piston in the depressed or down position.

Figure 6 is a sectional view of Figure 5 taken along the line VI-VI.

Figure 7 is a sectional view of the hydraulic pump in Figure 2 taken along the line VII--VII.

Figure 8 is a sectional view of Figure 6 taken along the line VIII-VIII.

Figure 9 is a sectional view taken on the line IX-IX of Figure 7.

Figure 10 shows a transmission supported upon said lift mechanism, which is being withdrawn from beneath a vehicle.

General construction The hydraulic lift mechanism shown in Figure 1 is comprised of a hydraulic liftingelement 6,

for convenience hereinafter sometimes termed a jack, a hydraulic pump I for operating the lifting element 6, and an adjustable gripping means 8 removably mounted upon said lifting element. The construction of the lifting element, the pump and the gripping means will be disclosed individually hereinafter.

For the purposes of convenience in description, the terms front or forward will be understood to refer to the leftward end of the lift mechanism as appearing in Figure l, and rear or rearward will be understood to refer to the rightward end of the lift mechanism as appearing in Figure 1. The terms upper and lower, or upwardly and downwardly shall be understood to refer to the lift mechanism or parts thereof when positioned and/or operating in its normal manner of use.

The lifting element As shown in the Figures 1, 2 and 3, the hydraulic lifting element 3 is comprised of a chassis I9 having a pair of identical chassis side plates II and I2 which are preferably made from steel plate of appropriate thickness, and which are substantially longer than wide. Said side plates are held in parallel, spaced relationship with respect to each other by means of a forward tubular member 83 and rearward tubular member i (Figs. 2 and 3). The two tubular members communicate at their opposite ends with suitable openings in said side plates II and I2 near opposite ends thereof, and are secured thereto by welding, brazing or other suitable means.

The rearward tubular member supports a rear axle I5 whose opposite ends preferably extend beyond said side plates II and I2. A pair of wheels I6 may be attached to said opposite ends in a conventional manner by means of the nuts I! (Figure 1). In a similar manner the forward tubular member I3 rotatably supports a forward axle I8, to the opposite ends of which a pair of wheels I9 may be attached by means of the nuts 20. The axles I5 and I8 may be of any convenient size and material, but are preferably fabricated from steel shafting.

The lift arm 23 (Figures 2 and 3) is comprised of a pair of substantially identical lift side plates 24 and 25 which are held in parallel, spaced relationship with respect to each other by means of the tubular lift bearing 26, the tubular head bearing 21, and the lift arm brace plate 28. The lift side plates 24 and 25, which are substantially longer than Wide and wider at one end than the other, are preferably made from steel plate of appropriate thickness. The brace plate 28, which is substantially longer than wide and is also preferably made from steel plate, is secured along its longitudinal edges perpendicularly to said lift side plates 24 and 25 along corresponding edges thereof. The said brace plate 28 is advantageously of such width that the lift arm 23 is receivable within and between the chassis side plates I I and I 2 of the chassis ID.

The wide ends of the lift side plates 24 and 25 are provided with aligned openings through which the tubular lift bearing 25 is snugly received. The narrow ends of the said side plates also have a pair of aligned openings through which the tubular head bearing 21 is snugly received. The said bearings, which are preferably parallel, extend beyond the outer, or non-adjacent, surfaces of the lift side plates 24 and 25 and are secured thereto by any suitable means such as by welding or brazing.

I 4 rotatably The lift bearing 26 is rotatably sleeved upon the forward tubular member I3 so that an operating clearance, only, remains between the extremities of said bearing and the inner, or opposed, side walls of the chassis side sheets II and I 2. Such arrangement positively ensures the centering of the lift arm 23 between the said chassis side plates.

The tubular head bearing 21 rotatably supports a head shaft 32 whose opposite ends extend out of said head bearing, and upon which the lift head 33 is rotatably supported. Said lift head, (Figures 1, 2 and 3) which may be fabricated from steel plate, has a head platform 35 and a pair of parallel, platform support legs 36 and 31 depending from and secured to opposite edges of the platform 35. The support legs 36 and 31 have a pair of aligned openings adjacent to their lower extremities through which the head shaft 32 extends for threaded association with a pair of head shaft nuts 38.

The platform 35 of the lift head 33 is provided with a circular opening 3I approximately at its center into which a cylindrical head bushing 34 is received. The upper edge of said bushing is preferably flush with the top surface of the platform 35 Whereas the lower edge of the bushing may extend substantially below said platform.

Another pair of aligned openings are provided in the support legs 36 and 3'! so that a pair of coaxial pivot rods 39 and M (Figure 2) fixedly supported therein will lie substantially between the head shaft 32 and the platform 35, and parallel therewith. The rods 39 and 4| extend beyond the remote surfaces of the legs 36 and 31, respectively, for pivotal engagement by the upper ends of a pair of head erecting bars 42 and 43, respectively. The lower end of said bar 43, Whose upper end is pivotally supported upon the rod M, is pivotally supported, as by means of a rivet 44, upon the forward end of the chassis side plate I2 adjacent to the lift plate 25. The axis of the said rivet 44 is in the same relative position with respect to the axis of the axle I8 as the axis of the rod M is with respect to the axis of the head shaft 32. Therefore, the bar 43, the lift side plate'25, the leg 31 and the chassis side plate I2 combine to create a movable parallelogram whereby the lift head 33 will be continuously held erect throughout all positions of normal operation of the lift arm 23.

The lower end of said bar 42, Whose upper end is pivotally supported upon the rod 39, is pivotally supported upon the forward end of the side sheet II in the same manner and in the same relative position as the bar 43. The purpose and operation of the bar 42 are the same as those of the bar 43 and therefore will not be described in further detail. Suflicient space is allowed between the side plates 24 and 25, and the side plates II and I2, respectively, to prevent interference with the bars 42 and 43, when the lift arm 23 is in its collapsed position and telescoped within the chassis II].

A piston support shaft 45 is snugly received through and extends beyond suitable, aligned openings in the lift side plates 24 and 25 intermediate the longitudinal extremities thereof. A bushing 48 (Figures 3 and 4) is sleeved upon said shaft 45 between the side plates 24 and 25 so that said lift side plates will bear against the extremities thereof when the piston support shaft nuts 41 (Figure 2) are tightened upon the threaded ends of piston support shaft 1::

The tubular piston bearing 50, which is preferably slightly shorter than the bushingIS'and rotatably supported thereon, is secured to the free end of the hydraulic piston 5! (Figures 3' and 4) by any suitable means such as welding or brazing. The hydraulic cylinder 52, with which said piston 5! is operably associated, is secured at its end remote from the piston, as by welding or brazing, to a cylinder support bearing 53. The bearing 53 is rotatably supported upon a slightly longer bushing M which is in turn supported on a cylinder support shaft 55. A pair of suitable aligned openings are provided in the chassis side plates H and 52 through which the said shaft 55 may extend for threaded engagement by the cylinder shaft nuts 58 which, when tightened, bring the chassis side plates H and I2 to bear against the opposite extremities of the bushing 54.

The hydraulic piston 5i and cylinder 52 may be of any convenient, conventional type. However, in this particular embodiment of the invention (Figure 4), the piston 5i has a hollow chamber 5'! with an inlet opening 58 near the free or outer end thereof into which an appropriate hose connection 59 may be securely fixed. The inner end of the piston 5i is provided with an outlet opening 62, communicating with the cylindrical chamber 63 of the cylinder and a liquid tight seal 64 which positively prevents the passage of by draulic fluid into that portion 65 of the chamber 63 between the piston 5i and the cylinder 52. Inasmuch as hydraulic seals and means for making hydraulic pistons and cylinders are well known in the art, further description of the construction of the piston and cylinder will be omitted.

A flexible hose t6 (Figures 1 and 2) of any conventional type, such as reinforced rubber, and usually longer than the hereinafter described jack handle t5, may be used between the hose connection 59 on the piston 5i and a similar hose connection fixture 61, secured to the circular pump base 58 of the hydraulic pump l, which is illustrated in Figures 5 through 9.

The hydraulic pump The hydraulic pump 1 (Figures 5 and '7) is comprised of a cylindrical casing H which is secured at its lower end, by means such as welding, to the pump base 68. A circular casing cap '12 may be threadedly or otherwise secured to the upper end of said cylindrical casing i l, and is provided with a suitable concentric vertical opening 13. A hollow plunger id is slidably held within said opening 13 and suitable, conventional packing seals 15 in said opening prevent the passage of hydraulic fluid between the cap '52 and the plunger 74. An appropriate retaining ring "it, which is secured to the inner end ll of said plunger '54, engages the lower side of the cap 52 when the plunger is moved to its uppermost position thereby preventing the accidental removal of said plunger from the opening l3.

A pressure cylinder kit, which is coaxial with the cylindrical casing H and the plunger 14, is seated at its lower end in the pump base 68 in any convenient manner, such as threadedly. The cylinder 86 extends upwardly into the hollow chamber 8! within the plunger 14 and terminates about midway between the upper and lower surfaces of the casing cap 12.

A piston pin 82 is snugly and slidably received within the coaxial opening 83 extending the full length of said pressure cylinder 8t. To the upper end of the said pin 82 is affixed a disk 84 against which the upper extremity of the piston spring 85 bears. The lower end of the spring 85, which is sleeved upon the pressure cylinder and around the piston pin 82 within the hollow chamber 8| of the plunger 14, bears against the base 68. Sufficient clearance is allowed between the outer wall of the pressure cylinder 30 and the inner wall of the hollow plunger 14 to permit smooth reciprocal movement of the plunger l4 over both the pressure cylinder and the spring 85 sleeved thereon.

The piston spring 85 yieldingly urges the piston pin 82 against the top Bl of the plunger and thereby causes both the plunger 14 and the piston pin 82 to remain at rest in an extended position. Any suitable, conventional sealing means 88 is provided within the upper end of the pressure cylinder 80 to prevent the upward escape of hydraulic fiuid between the piston pin 82 and the pressure cylinder 80.

The disk 84 is preferably slightly smaller than the inside diameter of the hollow plunger so that said plunger 14 is permitted some lateral movement without effecting the alignment of the piston pin 82 with respect to the pressure cylinder 80.

A conventional, vertical outlet valve, such as the spring loaded, ball and socket valve 90 (Fi ures 6 and 7), which provides a fluid outlet from the reservoir 86 and is seated in the pump base 68, communicates with one end of a horizontal passageway 9| which passageway passes diametrically through a substantial portion of said base 68. The opening 83 in the pressure cylinder 83 communicates at its lower end with said passageway 9| by means of the vertical canal 92 in the base 68. That end of the passageway 9i remote from said valve 90 opens into a relatively larger, coaxial threaded outlet valve opening H2 in one side of the base 63. A horizontally disposed, spring loaded outlet valve 93, having a valve body I I0, is threadedly held within said threaded opening I I2. That end portion Hit or" said valve body l l0 adjacent to the passageway 9| is of less diameter than the internal diameter of the adjacent portion of the threaded opening I I2 thereby providing an annular chamber 91 between said body end H33 and the side walls of said opening H2.

The valve body H0 has a cylindrical, coaxial ball chamber H3 which is open at that end of said body remote from said end portion I09 and contains a conventional ball valve H5 backed by a valve spring I IS. The closed end of said chamber H3 is provided with a passageway H4 which is coaxial with the ball chamber H3 and communicates with said passageway 9!. The ball H5 is normally seated in that end of the passageway H4 opening into the chamber H3 in a conventional manner. That end of the ball spring H6 remote from the ball I I5 bears against the inner end of the hose connection 6! which threadedly engages the opening H2. The valve 93 provides an outlet through which hydraulic fluid may flow from the pressure cylinder 80 through the hose connection 611 and the flexible hose B6 to the hydraulic piston 5i.

An inlet opening H1 is provided through the side wall of the end portion I39 of the valve body H0 thereby permitting hydraulic fluid to flow freely from the ball chamber H3 to the annular chamber 91. The hydraulic fluid is, however, prevented from passing from the said annular chamber 91 between the inner end of the valve body H0 and the base 68 directly to the passageways 9| and H4, thereby preventing bypassing of the outlet valve 33. Thus, when the pisston pin 82 is raised with the fluid reservoir 86 full of a hydraulic fluid, the reservoir outlet valve 90 is opened and the base outlet valve 92 is held closed. When the piston pin 82 is depressed, the base valve 93 is opened and the reservoir valve 90 is held closed.

A cylindrical return valve opening 99, (Figure 8) containing a fluid return valve 94, is preferably positioned in the pump base 68 so that its axis extends horizontally toward the inner end of the ball chamber H3 and is substantially perpendicular to the axis thereof. A horizontal return passageway 95 connects the annular chamber 91 with the return valve opening 99, and a vertical return passageway 96 connects said return valve opening 99 with said fluid reservoir 86.

The inlet valve 94 may be comprised of an internally and externally threaded sleeve 98 threadedly secured within said return valve valve opening 99. A partially threaded valve pin IOI, which is threadedly held within the sleeve 98 has an outer end I02 extending through the sleeve 98 and beyond the base 68. The inner end I03 of the pin I engages a ball valve I04, which ball may be caused to seal the entrance of the horizontal return pasage 95 into the valve opening 99 by appropriate rotation of the pin IOI. A bar I05 secured to the outer end I02 of the pin IOI facilitates rotation of the pin IOI for the purpose of opening or closing the return passage 95.

A substantially U-shaped hande 69 (Figure 1, 2 and 3) may be rigidly secured at its adjacent extremities to the forward ends of the chassis side plates I I and I2 by any suitable means such as the bolts I01. However, said handle may also be flexibly or pivotally secured to the chassis I0 without departing from the scope of the invention if suitable stops are provided to limit its pivotal motion. Said handle 89, which is preferably fabricated from steel bar stock, has a contoured portion I08 remote from said chassis I0 within which the pump I may be securely but removably engaged and gripped around its casing I I. The hande I06 is aflixed to the chassis side plates II and I2 at such an angle with respect to the horizontal that its contoured portion I08 will hold the pump I in operative position when the jack 6 is in operating position.

The adjustable gripping device 8 (Figure 1-), which may be of any convenient type, is here comprised in general of a swivel post I IS, a positioning unit I I9 and a gripping fixture Hi. The gripping device 8 is mounted upon the platform 35 of the lift head 33 by means of the swivel post IIB which is pivotally and removably supported within the head bushing 34. Of course, the gripping device may be fixed rigidly to the lifting arm and the swiveling function obtained by replacing the wheels herein shown by swiveled casters. Since a complete description of the construction and operation of the particular device 8 herein illustrated may be found in our copending application entitled Transmission Gripping Device and filed concurrently herewith, now Patent No. 2,523,734 further details thereof will be omited and reference made thereto.

Operation Under normal conditions the hydraulic lift mechanism, to which this invention relates, is pushed or pulled about by means of the, handle 69. While the lift mechanism is in transit the pump I is conveniently held and carried within the contoured portion I08 of the handle 69.

When the lift mechanism has been properly positioned under the vehicle transmission, or other object to be raised or lowered, the pump I may be removed from the handle 69 or may be operated while still held within said handle, depending upon safety and/or convenience in the the particular case. The adjustable gripping device 8 is appropriately adjusted and secured to the object to be supported by the lift mechanism, which mechanism is then ready for operation.

The inlet valve 94 is closed by appropriate rotation of the valve pin IOI so that hydraulic fluid cannot pass from the hose 66 through the return passages 95 and 96 to the fluid reservoir 86. The pump I is now set to raise the lift arm 23 by actuating the plunger I4. When the plunger 14, which may be actuated either by hand or by foot, is depressed against the compression of the spring 85, the piston pin 82 is also moved downwardly thereby displacing hydraulic fluid from the pressure cylinder opening 83 through the canal 92, the passageway 9|, the outlet valve 93 and the flexible hose 66 into the hollow chamber 5! of the hydraulic piston 5I. The flow of hydraulic fluid into the hollow chambers 5! and 63 of the piston 5| and cylinder 52, respectively, effects an outward movement of the piston 5I from within the chamber 63 in a conventional manner. Since the cylinder is secured to the body member I0 and the piston is secured to the lift arm 23, such outward movement of the piston with respect to the cylinder effects an upward or lifting movement of the lift arm 23 (Figure 3). Inasmuch as the operation of a conventional hydraulic piston, such as embodied herein, is well known to the art, further description thereof will be omitted.

When the depressed plunger I4 is released, the spring 85 effects an upward movement of both the piston pin 82 within the opening 83 and the plunger 14 by bearing against the disk 84. Such upward movement of the pin 82 opens the outlet valve and draws hydraulic fluid out of the reservoir 86 through the valve 90, the passageway 9I, the vertical canal 92 and into the opening 83 in the pressure cylinder 80. The horizontal valve 93 is held closed during the upward movement of the piston pin 82 by the back pressure of hydraulic fluid in the hose 66, the spring H6 and the suction of the piston pin 82, thereby preventing the return of the hydraulic fluid which recently passed theret-hrough on its way to the hydraulic piston 5I.

When the plunger I4 is again depressed, the fluid is again forced out of the pressure cylinder opening 83 through the passageway 9|, the horizontal valve 93, and the hose 66 in the same manner and with the same effects as recited above. This cycle may be repeated, by depressing the plunger 14 and allowing the spring 85 to return the plunger to its extended position, until the lift arm 23 has been raised, by the corresponding extension of the hydraulic piston, to the position desired or required.

The head platform 35 of the lift head 33 is constantly held in a horizontal position during the raising of the lift arm 23 by means of the head erecting bars 42 and 43, as hereinbefore described.

In order to lower the lift arm 23, the inlet valve 94 is opened by rotating the pin I 0| in a direction opposite to that which closed the said valve, thereby permitting the ball I 04 to recede from the opening of the passage 95. The hy- 9 draulic fluid is then permitted to flow out of the hydraulic piston through the hose 66, the ball chamber H3, the inlet opening ill, the annular chamber 91, the passage 95, the passage 9t, and

.into the fluid reservoir 86, (Figures 3, 6, '7, 8 and 9). The rate of release is controlled by the amount of rotation of the pin Nil.

The upper extremity of the piston pin 82 is held in contact with the top 8! of the hollow plunger 14 by means of the coiled spring 85, but said piston is not secured to said plunger in any way. Thus, the plunger 14 is permitted a reasonable amount of lateral movement, which usually developes in a foot operated implement, with-out destroying the alignment of the piston pin 82 within the pressure cylinder 80.

By providing a hose 66 of substantial length the pump may be operated at a like distance from the rest of the hydraulic jack 6, thereby increasing the safety of the lift mechanism and enabling its effective use under objects which would otherwise be inaccessible with present types of lift mechanisms.

In one preferred application (Figure of the hydraulic lift mechanism to which this'invention relates, the adjustable gripping device 8 may be removed from the lift head 33 so that the pump 1 and jack 6 may be used to raise one side of a vehicle such as a passenger car I22. Blocks I23 may then be placed under the wheels on the raised side of the car and the jack lowered and removed. The device 8 is then placed upon the lift head again and the entire lift mechanism is run under the car to engage and support any heavy part, such as a hydraulic transmission I'M, which must be removed from the car for repair or replacement. The lift mechanism holds the transmission, which is selected in this description for illustrative purposes only, firmly in place with respect to the car while said transmission is being disconnected from said oar. Then the lift arm 23 is lowered, as hereinbefore described, and the transmission is rolled out from under the car. If, as is sometimes the case, the transmission is too large to be drawn straight out from under the car, theentire lift mechanism can be tilted upon its rear wheels (Figure 10) to accomplish the removal. This is made possible by causing the adapter to actually grip the transmission.

The lift mechanism may also be used to return a new or repaired transmission 24 to its proper position under the car and hold the transmission in place while it is being connected to the car. When the part is properly secured in place, the lift arm is again lowered and the lift mechanism removed. The jack and pump may then be used to lower the car ofi of the blocks. Thus, the entire job of removing heavy parts, such as said transmission, from a motor vehicle may be accomplished easily and safely by one workman and our hydraulic lift mechanism.

Although the above mentioned drawings and description apply to one particular, preferred embodiment of the invention, it is not my intention, implied or otherwise, to eliminate other variations or modifications which do not depart from the scope of the invention unless specifically stated to the contrary in the hereinafter appended claims.

We claim:

1. In a hydraulic lift mechanism, the combination comprising: a wheeled carriage including a pair of substantially parallel side plates and combined spacer and wheel supporting means extending therebetween; an elongated cantilever arm pivotally supported at one end upon one of said wheel supporting means between said plates near one end of said carriage; said arm having lift means at its free end a hydraulic cylinder pivotally affixed to said plates at a point spaced from said one end of said carriage and operatively associated with a piston, said piston being pivotally affixed to said cantilever arm interme diate its opposite ends; actuating means including a cylindrical reservoir, a pump cylinder concentrically housed within said reservoir and operable from a reciprocable plunger, said plunger being operable along the axis thereof with a power stroke and a spring urged return stroke, passageway and valve means operatively connecting said pump and reservoir; a substantially U- shaped handle rigidly aflixed at each of it free ends to each of said side plates, respectively, said handle having a curved portion remote from said free ends releasably supporting said cylindrical reservoir, said handle being affixed to said side plates at such an angle with respect to a horizontal surface supporting said carriage that said actuating means may contact said surface while being gripped by said curved portion; and means including a flexible hose substantially longer than said handle operatively connecting said pump and said hydraulic cylinder.

2. A hydraulic lift mechanism comprising in combination: a wheeled carriage; an elongated cantilever arm supported at one end upon said carriage and having at the other end thereof, means adapted to receive article engaging means; a hydraulic cylinder and associated piston for raising the free end of said arm with respect to said carriage; actuating means including a cylindrical fluid reservoir and a hydraulic, foot operable pump concentrically housed within said reservoir; a generally U-shaped handle including a pair of spaced resilient members the free ends of which are fixedly supported upon said carriage and having onset portions near to the closed ends of said U-shaped handle for yieldably and releasably supporting said cylindrical reservoir; and a flexible hose connecting said actuating means to said hydraulic cylinder, said hose being longer than said handle.

3. In a hydraulic lift mechanism, the combination comprising: a wheeled carriage including a pair of substantially parallel side plates; an elongated cantilever arm pivotally supported at one end upon said carriage near one end thereof; a hydraulic cylinder pivotally affixed to said plates at a point remote from the point at which said cantilever arm is supported on said carriage, said hydraulic cylinder being operatively associated with a piston and said piston being pivotally fixed to said cantilever arm at a point spaced from its point of fixing to the carriage; actuating means including a reservoir, a pump cylinder within said reservoir and operable from a reciprocable plunger, said plunger being operable along the axis thereof with a power stroke and a spring return stroke, passageway and valve means operatively connecting said pump and said reservoir; a substantially U-shaped handle rigidly afiixed at each of its free ends to each of said side plates, respectively, said handle having curved portions remote from said free ends releasably supporting said cylindrical reservoir and said handle being rigidly aiflxed to said side plates at such an angle with respect to a horizontal surface supporting said carriage that said cylindrical actuating means may contact said surface While being gripped by said curved por- 'tions; and means including a flexible hose operatively connecting said pump and said hydraulic cylinder.

4. In a hydraulic lift mechanism, the combination comprising: a wheeled carriage including a pair of substantially parallel side plates; an elongated cantilever arm pivotally supported at one end upon said carriage; a hydraulic cylinder pivotally affixed to said plates at a point spaced from the point at which said cantilever arm is supported on said carriage, said hydraulic cylinder being operatively associated with a piston and. said pisto .1 being pivotally fixed to said cantilever arm at a point spaced from its point of fixing to the carriage; actuating means including a reservoir, a pump cylinder operable from a reciprocable plunger, passageway and valve means operatively connecting said pump and said reservoir; a substantially U-shaped handle rigidly afiixed at each of its free ends to each of said side plates, respectively, said handle having portions remote from said free ends releasably supporting said cylindrical reservoir and said handle being rigidly affixed to said side plates at such an angle with respect to a horizontal surface supporting said carriage that said cylindrical actuating means may contact said surface while bein gripped by said curved portions; and means including a flexible hose opera'tively connecting said pump and said hydraulic cylinder.

5. In a hydraulic lift mechanism, the combination comprising: a wheeled carriage including a pair of substantially parallel side plates; an elongated cantilever arm pivotally supported at one end upon said carriage near one end thereof: a hydraulic cylinder pivotally afiixed to said plates at a point remote from the point at which said cantiliver arm is supported on said carriage,

said hydraulic cylinder being operatively associated with a piston and said piston being piv otally fixed to said cantilever arm at a point spaced from its point of fixing to the carriage; actuating means including a reservoir, a pump cylinder within said reservoir and operable from a reciprocable plunger, said plunger being operable along the axis thereof with a power stroke and a spring return stroke, passageway and valve means operatively connecting said pump and said reservoir; a substantially U-shaped handle including a pair of spaced resilient members the free ends of which are rigidly supported upon said carriage, and the parallel arms of which have offset portions near the closed end of said u of said U-shaped handle for yieldingably and releasably supporting said cylindrical reservoir; and means including a flexible hose operativel connecting said pump and said hydraulic cylinder.

JOHN O. STEPHENSON. JOHN H. HILLIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,241,418 Mosher Sept. 25, 1917 1,450,114 Rehak Mar. 27, 1923 2,189,010 Lewis Feb. 6, 1940 2,465,653 Leterman Mar. 29, 1949 2,523,734 Stephenson et al. Sept. 26, 1950 FOREIGN PATENTS Number Country Date 278,531 Italy Oct. 13, 1930

Images