US3047269A - Hydraulic jack - Google Patents

Description

R. RENSHAW HYDRAULIC JACK July 31, 1962 2 Sheets-Sheet 1 Filed Aug. 30, 1960 July 31, 1962 R. RENsHAw HYDRAULIC JACK Filed Aug. 30, 1960 2 Shee's-Shee'fl 2 State The present invention relates to a hydraulic jack and, more particularly, to a hydraulic toe jack.

It is the general object of the invention to provide a new and improved hydraulic jack having a lifting toe which may be lowered to a position close to ground or floor level whereby to facilitate raising objects supported at ground or floor level.

An important object of the invention is to provide a new and improved hydraulic jack having `a pair of spaced apart hydraulic pistons and. a lifting toe depending from a cross head connected between the upper ends of the pair of pistons.

Another important object of the invention is to provide a new and improved hydraulic toe jack of the Character described wherein the body of the jack is provided with an internal hydraulic fiuid reservoir and wherein a manually operable pump assembly is mounted on the jackV body for raising and lowering the pistons.

A still -further object of the invention is to provide a new and improved hydraulic toe jack of the character described which is adapted to be connected to an external pressure source for raising and lowering the pistons.

Still another important object of the invention is to provide a new and improved hydraulic toe jack of the character described wherein the bending moment resulting from the lifting surface of the toe being offset from the center line of the cylinders is absorbed by the jack body whereby to prevent such bending stresses being exerted on the lifting pistons.

Further objects of the invention are to provide a new and improved hydraulic toe jack of the Character described which is simple in construction, which is economical to produce, which is highly eflicient and adapted to provide a relatively high lift, and which is provided with `a safety ratchet device adapted to prevent lowering of the lifting toe in the event of hydraulic failure.

Certain other objects of the invention will, in part, be obvious, and will in part appear hereinafter.

For a more complete `understanding of the nature and scope of the invention reference may now be had to the accompanying drawings wherein:

FIG. l is `a side elevational view of a preferred embodiment of the hydraulic toe jack;

FIG. 2 is a front elevational view of the hydraulic toe jack of FIG. l;

FlG. 3 is a rear elevational view of the same;

FIG. 4 is a top plan view of the same;

FIG. 5 is a horizontal section taken generally on the line 5-5 of FlG. 1;

FIG.. 6 is an enlarged Vertical section taken generally on the line 6-6 of FlG. 5;

FIG. 7 is an enlarged fragmentary Vertical section taken generally on the line 7-7 of FIG. 5;

FIG. 8 is a horizontal section taken generally on the line 8-8 of FIG. 7; and

FIG. 9 is a fragmentary Vertical section similar to FlG. 6 of a modified form of the jack which is adapted to be connected to an external source of hydraulic pressure.

As best illustrated in FIGS. 1 and 6, `a prefcrred embodiment of the hydraulic toe jack includes a generally Vertical or upright frame or body 10 which may be formed' of a steel or aluminum casting and which is provided with a vertical'ly disposed front wall 14 and a forwardly disposed stabilizing foot 11. The rear portion of the body iii is provided with a vertcally disposed inner compartment 12 which defines an internal hydraulic fiuin' reservoir 13. The lower end of the reservoir 13 is open at the rear of the body 10 and a filler opening 15 at the upper end of the reservoir 13 is closed by a removable plug 16 having a breather hole formed therein.

A passage 18 which is preferably square in horizontal cross-section, extends vertically through the full height of the body 1d forwardly of the reservoir 13 and midway between the sides of the body 10 for a purpose to be described. Also extendng through the full height of the 'body 10 are a pair of hydraulic cylinders 20 located on either side of the square passage 18. The lower end of each cylinder 2d is closed by a steel plug 22 and a sealing gasket 23. It is noted that the hydraulic fluid reservoir 13 is designed so as to add additional strength to the portion of the jack body 10 containing the cylinders 2% and the square passage 18. The front wall 14 of the jack body 10 is provided with a centrally located Vertical slot 19 which extends upwardly from the bottom surface of the body 10 to a point spaced from the top of the body 1d a distance approximately equal to 1A of the overall height of the jack body 10'. As best illustrated in FIGS. 5 and 8, the slot 19 intersects or opens into the square passage 18 with the width of the slot 19 being substantially less than the corresponding dimension of the square passage 18.

Each cylinder 20 is provided with a piston 25 the upper portion of which extends through a bronze bushing 26 secured in the upper end of each cylinder 20 by a suitable mounting member 27. The pistons 25 project a short distance above the top of, the body 10 When in their lowermost positions. A reduced-in-diameter lower end portion 28 of each piston 25 is provided with a bronze bushing 29 and a further reduced-in-diameter, partially threaded lower end 30 of each piston 25 is provided with a leather sealing cup 31, a washer 32 and a pair of lock nuts 33. Hydraulic fluid directed under pressure simultaneously into the lower ends of the two cylinders 20 through a pair of passages 34 formed in the body 19 (FIG. 5) will thus cause simultaneous upward movement of the two pistons 25 in a well-known manner.

The upper end of each of the pistons 25 is reduced-ndiameter, as at 36, with the reduced-in-diameter upper end portions 36 being received in a pair of downwardly opening bores 37 located in opposite ends of a cross head 39, which may be in the form of a high tensile alloy drop forging. Each reduced-in-diameter portion 36 of the pistons 25 is secured in its bore 37 in the cross head 39 by a transverse looking pin 40. The central portion of the upper surface of the cross head 39 is provided with a. standard jack head 42 for conventional lifting operaions.

The lhydraulic jack is provided with a lifting toe 41, which may be in the form of a high tensile alloy drop forging, whereby to permit raising objects disposed close to ground or floor level. The lifting toe 41 is characterized by a vertically extending square shank portion 46 which is slidably mounted in the square passage 18 and by a right angular toe portion 45 which is disposed forwardly of the Vertical front wall 14 of the jack body 10. The toe portion 45, which is integrally connected to the lower end of the shank portion 46 by a narrow neck portion 49 extending through the slot 19, is provided with a horizontally disposed lifting surface 47 and a vertically disposed rear surface 48 which is slidably engaged with la Vertical front wall 14- of the jack body 10. The shank portion 46 of the lifting toe is provided on its upper end with a threaded portion 50 which is tightly secured in a downwardly opening threaded bore 51 centrally located in the cross head 39 (PIG. 2). Thus, when the pair of pistons 25 are raised hydraulically, the cross head 39 seaatena July 81', 1962 acer/,269

cured to the upper ends of the pistons 25 serves to pull up the lifting toe 41. The hydraulic lifting force is thereby transferred to the toe portion 45 of the lifting toe 41. In order that the toe portion 45 may be lowered as far as possible to facilitate lifting objects supported close to the floor or ground level, an opening 52 is provided in the stabilizing foot portion 11 of the jack body 10, which opening 52 is of a size to receive the toe portion 45 when in its lowermost position.

With the rear surface 48 of the toe portion 45 being slidably engageable with the Vertical front wall 14 of the jack body`10, the outer surface of which may be hardened by suitable heat treatment processes, the bending moment resulting from the lifting surface 47 of the lifting toe being ofiset forwardly of a Vertical plane passing through the axes of the pair of cylinders 20 is absorbed by the body of the hydraulic jack thus preventing the undesirable possiblity of such bending moments being exerted directly onthe pistons 25. Thus the only forces exerted on the pistons 25 are the Vertical lifting forces for which the pistons 25 are designed.

If desired, additional means may be provided to insure that such bending moments will be absorbed by the body 10 of, the hydraulic jack rather than having such bending moments exerted on the pistons 25. As illustrated in FIGS. 7 and 8, a roller 54 may be rotatably fitted in a transversely extending bore 55 which is formed in the lower end of the shank portion 4-6 and which is open at the-fear thereof whereby the roller 54 projects slightly rearwardly of the square shank portion 46 for abutting engagement against the rear wall of the square passage 18, which rear wall may also be hardened by heat treatment. With this arrangement, the bending moment developed during a lifting operation is also transmitted to the jack body 10.

In the embodiment of the hydraulic jack illustrated in FIGS; 1-8, a manually operable pump assembly 60 is mounted on the rear of the jack body 10. As best illustrated in FIG. 6, the pump assembly 60 includes a body portion 61 having a integral flange 62 at one end thereof for mounting the pump assembly 60 on the rear surface of the jack body 10 by means of suitable bolts 63. A pump unit 64 is thrcadedly secured in a bore 65 formed in the top of the body portion 61 in a manner adapted to provide an internal annular passage 66 therebetween. A fluid passage 67 formed in the body portion 61 extends between the annular passage 66 and the lower open end of the hydraulic fluid reservoir 13. The pump unit 64 includes a piston 69 which is reciprocal in a cylindrical pump chamber 70. The pump chamber 70 is in communication with the reservoir passage 67 through an intake passage 16, which includes a ball check valve 72. An outlet passage 76, which includes a ball check valve 74 normally closed by a spring 75, leads from the pump chamber 70 Vto a passage 77 which is in communication with the two p'assages 34 leading to the lower ends of the pair of cylinders 20.

During each outward stroke of the piston 69, hydraulic fiuid is drawn into the chamber 70 from the reservoir 13 through the passages 67 and 71 and past the ball check valve 72. During each inward stroke of the piston 69, this hydraulic fluid is forced from the chamber 70 into the lower ends of the cylinders through the passages 76, 77 and 34 and Vpast the ball check valve 74. Thus, upon actuation of the pump piston 69, hydraulic fluid is directed under pressure to'the lower ends of the cylinders 20 whereby to raise the pistons and the cross head 39 connected to the upper ends thereof, the cross head 39 servingto raise or pull up the lifting toe 41.

To permit Controlled lowering of the pistons 25, a passage 80 is provided in the body portion 61 which extends between the annular passage 66 and the passage 77 outwardly of its connection to the ontlet passage 76. Communication between the passage 80 and the passage 77 is normally blocked by a release valve S1 which is threadedly mounted in the body portion 61 and is provided With an external knob 82 for manual manipulation thereof. When it is .desired to lower the pistons 25, the knob 82 is rotated in a direction to move the release valve 81 out- Wardly whereby to permit the hydraulic fluid to flow from the cylinders 20 through the passages 34, the passage 77, the passage 80, the annular passage 66 and the passage 67 back to the reservoir 13. With this arrangement the pistons 25 may be simultaneously raised and lowered upon actuation of the pump piston 69 and manipulation of the release valve S1, respectively.

The outer end of the pump piston 69 is pivotally connected to a link member S4, intermediate the ends thereof, by a pin 85, which link 84 is pivotally mounted at one end on a pin 36 which is supported between a pair of lug members 87 which are mounted in spaced apart relationship on the jack body 10. The opposite end of the link member S4 is provided with a socket 88 which is adapted to receive one end of a handle (not shown) to facilitate operation of the pump assembly 60. To prevent leakage of the hydraulic fiuid a pair of sealing rings 79 and 83 are provided between the body portion 61 of the pump assembly 60 and the rear surface of the jack body 10. Likewise, a pair of sealing rings 68 and 78 are provided in the pump unit 64.

As a safety measure, provision is made for retaining the cross head 39 and the lifting toe 41 in a raised position in the event of a hydraulic failure. The rear surface of the square shank portion 46 of the lifting toe is provided with a vertically etxending rack formation 90 which is adapted to be engaged by one end of a Safety arrn 91, the opposite end of which arm is pivotally mounted on a pin 92 which is supported zbetween a pair of spaced apart lug members 93 secured to the rear surface of the jack body 10 adjacent the top thereof. This arrangement,

' bly 60, for actuating the hydraulic toe jack, the pump assembly 60 may be replaced by an adapter plate 96, as illustrated in FIG. 9. The adapter plate 96 is provided with a flange portion 97 whereby the adapter plate 96 may be mounted on the rear surface of the jack body 10 by suitable bolts 98. A threaded socket 99 which s adapted to receive a hose connection of an external source of hydraulic pressure is provided in the adapter plate 96. The socket 99 communicates with the two passages 34 which are formed in the jack body 10 and which extend into communication with the lower ends of the two cylinders 20 whereby hydraulic fluid under pressure may be directed from the external pressure source to the cylinders 20 to raise the pistons 25. A sealing ring 100 is provided between the adapter plate 96 and the rear surface of the jack body 10 to prevent leakage of the hydraulic fluid.

It will be understood that certain changes may be made in the construction or arrangement of the hydraulic toe jack disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

l. A hydraulic jack comprising, a body, a pair of spaced apart, vertically extending cylinders formed in said body, a yvertically extending passage formed in said body between said cylinders in alignment therewith, a pair of pistons disposed one in each of said cylinders, a lifting toe characterized 'by 'a vertically elongated shank portion slidably disposed in said vertically extending passage and operably connected at its upper end to the upper ends of said pair of pistons for Vertical movement therev with and by a 'toe portion disposed normally to said shank portion and projecting forwardly therefrom through a vertical slot formed in the front surface of said body with the lifting surface of said toe portion being disposed adjacent the lower ends of said pistons, said shank portion of said lifting toe bearing against the rear surface of said vertically extending passage formed in said body whereby to'transmit to said body the bending moment resulting from the lifting surface of said -toe portion being disposed forwardly of said pair of pistons, and hydraulic means for simultaneously raising 'and lowering said pair of pistons and said lifting toe.

2. A hydraulic jack comprising, a body having a hydraulic fluid reservoir 'formed therein, a pair of spaced apart, vertically extending cylinders formed in said body, a vertically extending passage formed in said body between said cylinders in alignment therewith, a pair of pistons disposed one in each of said cylinders, a lifting toe characterized 'by 'a vertically elongated shank portion slidably disposed in said 'vertically'extending passage and operably connected at its upper end to the upper `ends of said pair of pistons for Vertical movernent therewith and by a toe portion disposed normally to said shank portion and projecting forwardly therefrom througha Vertical slot formed in the 'front surface of said body with the lifting surface of said toe portion being disposed adjacent the lower ends of said pistons, said shank portion of said lifting toe bearing against the rear surface of said vertically extending passage 'formed in said body whereby to 'transmit to said body the -bending moment resulting fro-m the lifting surface of said toe portion being disposed [forwardly of said pair of pistons, and a manually operable pump `assembly mounted on said body and adapted for directing hydraulic fluid under pressure from said reservoir to the lower ends of said pair of cylinders simultaneously 'whereby to raise saidpair of pistons and said lifting toe. i

3. A hydraulic jack comp'rising, a vertically disposed body, a pair of spaced apart, vertically extending cylinders 'formed in said body w'th the upper ends of said cylinders being open at the top of said body, a pair of pistons disposed one in each of said cylinders and projecting above the top of said body when in their lowermost positions, a vertically extending passage formed in said body between said pair of cylinders with 'the 'front surface of said body being provided 'below its upper edge with a continuous Vertical slot which 'opens into said passage, a lifting toe characterized by 'a shank portion guidingly slidable in said passage and having its upper end operably 'connected to the upper ends of said pair of pistons and by an integral toe portion projecting forwardly out of said slot adjacent the lower end of said shank portion, and hydraulic means for simultaneously directing hydraulic fluid under pressure to the lower ends of said cylinders for raising said pistons and said lifting toe connected thereto. p

4. A hydraulic jack comprising, a vertically disposed body, a pair of spaced apart, vertically extending cylinders formed in said body with the upper ends of said cylinders being open at the 'top of said body, a pair of pistons disposed one 'in each of said cylinders and projecting above the top of said body when in their lowermost positions, a vertically extending groove formed in the 'front wall of said body between said pair of cylinders, a lifting toe characterized by ashank 'portion slidable in said groove and having its upper end 'operably connected to the upper ends of said pair of pistons and by an integral toe portion `at the lower end of said shank portion which 'projects forwardly 'from said groove, hydraulic means 'for simultaneously directing hydraulic fluid under pressure to the lower ends of said cylinders 'for raising said pistons and said lifting toe connected thereto, a vertically 'disposed rack forrnation on said shank portion of said lifting toe, and a safety arm 'pivotally mounted on said body for latehing engagement with said rack forrnation whereby to 'pre- 6 vent uncontrolled lowering of said lifting toe in the event of a hydraulic failure.

5. A hydraulic jack comprising, a vertically disposed body, a pair of spaced apart, vertically extending cylinders Aformed in said body with the upper ends of said cylinders being open at the top of said body, a pair of pistons disposed one in each lof said cylinders and projecting above the top of said body When in their lowermost positions, 'a vertically extending groove formed in the front .face of said body between said pair of cylinders, a lifting toe characterized by a shank portion sli'dably confined in said groove'and operably connected -at its upper end to the upper ends of said pair of pistons 'and by va forwardly projecting toe portio'n at the lower end of said shank portion for supporting an object to be raised, hydraulic means for sirnultaneously directing hydraulic fluid under pressure to the lower ends of said cylinders for |raisin'g said pistons and said lifting toe connected thereto, and a roller carried on the lower end of the shank portion of said lifting toe `for engagement with the rear surface of said groove Whereby the bending moment resulting from said toe portion vbeing disposed forwardly of the pistons is absorbe'd by Said jack body.

6. A hydraulic jack compn'sing, a vertically disposed body, a hydraulic fluid reservoir formed in said body, a pair of spaced apart, vertically extending cylinders formed in said body with the upper ends of said cylinders being open at the top of said body, 'a pair of pistons disposed one in .each of said cylinders with the upper ends thereof projecting above the top of said vbody when in their lowerrnost positions, a vertically extending passage formed in said body between said pair of cylinders with the front wall of said body being provided below its upper edge with a continuous vertically extendin'g slot w'hich opens into said passage, a lifting toe characterized by a shank portion slidable in said passage and operably connected to the upper 'ends of said pair of pistons and by `a toe portion at the lower end of said shank portion which projects forwardly of said front body wall through said slot, and a pump assemb'ly mounted on said body including a manually operablle handle and passage means connecting the inlet of said pump 'assembly to said reservoir and the outlet of s'a'id pump asse'mbfly to the lower ends of said pair of cylinders whereby actua-tion of said pump handle is effective to direct hydraulic fluid under pressure from said reservoir to the lower ends of both of said ,cylinders for raising sa'id pistons and said lifting toe connected thereto.

7. A hydraulic jack 'comprisingg a vertically disposed body, a hydraulic fluid reservoir formed in said body, a pair of spaced apart, vertically extending cylinders formed in said body with the upper ends of said cylinders being open at the top of said body, 'a pair of pistons Vdisposed one in each of said cylinders with the upper ends thereof projecting above the top of said body when in their lowermost positions, a vertically extending groove lformed in the front surface o'f said body between said pair of cylinders, -a lifting toe characterized by a shank portion slidable in said groove 'and operably connected at 'its upper end to the upper ends of said pair of pistons -an d by an integra'l toe portion at the lower end of said shank portion which projects forwardly from said groove, 'a pump `assembly mounted on the rear surface of said bodyinclu'dinig a manually operable handle and passage means connecting the inlet of said pump `assembily to said reservoir and the 'outlet of said pump assemblyv to the 'lower ends 'of said pair of cylinders whereby actuation of said pump handle is effective to direct hydraulic fluid under pressure from said reservoir to the lower ends of both of said cylinders for raising said pistons and said lifting toe connected thereto, said pump assernbly having a manually operable release valve for controlled lowering o'f said pistons and said lifting toe, a vertically extendin'g rack formed on said shank .portion 7 of said lifting toe, and a safety arm pivotally mounted on said body for latching engagement with said rack whereby to prevent uncontro-lled lowering of said lifting toe in the event of a hydraulic `failure.

8. A hydraulic jack comprising, a vertically disposed body, -a hydraulic fluid reservoir formed 'in said body, a pair of spaced apart, vertically extending cylinders formed in said body with the upper ends of said cylinders being open at the top of said body, a pair of pistons disposed one in each of said cylinders With the upper ends Ihereof projecting above the top of said body when in their llowermost positions, a vertically extending groove formed in the front wall of said body between said pair of cylinders, a lifting toe oharacterized by a shank portion slidably confined in said groove and having its upper end operably connected to the upper ends of said pair of pistons and by an integr-al toe portion projecting forwardly from said groove at -the lower end of said shank portion for supporting an object to be raised, a pump assembly mounted on said body and including a manually operable handle and passage means connecting the inlet of said purnp assembly to said reservoir and the outlet of said pump assembly to the lower ends of said pair of cylinders whereby actuation of said pump handle is effective to direct hydraulic flui'cl under pressure from said reservoir simultaneously to the lower ends of said pair of cylinders for raising said pistons and said lifting toe connected thereto, and a roller carried on the lower end of said shank portion of said lifting toe vfor engagement With the rear surface of said groove whereby the bending moment resulting from said toe portion being disposed forw'ardly of said pistons is absorbed by said jack body.

9. A hydraulic jack comprising, an upright body having a vertically disposed front wall and a forwardly projecting stabilizing foot portion, a pair of laterally spaced, vertically extending cylinders formed 'in said body and being open at the top thereof, a pair of pistons disposed one in each of said cylinders and adapted to project above the top of said body when in their lowermost positions, a cross head connected between the upper ends of said pair of pistons and having a lifting surface on the top thereof, a vertically extending passage formed in said body midway between said pair of cylinders, a vertically extending slot formed in said front wall of said body and intersecting said vertically extending passage, a lifting toe characterized by an elongated shank portion slidable in said vertically extending passage and 'having its upper end secured in said cross head and by a forwardly disposed toe portion having a horizontally disposed lifting surface and a vertically disposed rear surface which is slidably engageable with s'aid vertically disposed front wall of said body, said toe portion being integrally connected to the lower end of said shank portion by a neck portion which extends through said slot, hydraulic means for directing hydraulic fluid under pressure simultaneously to the lower ends of said pair of cylinders for raising said pair of pistons and said lifting toe connected thereto by said cross head, the bending moment resulting from said lifting surface of said toe portion being disposed forwardly of the center line of said cylinders being absorbed by said jack body through the en gagement of said rear surface of said toe portion with said front `wall of said body whereby to prevent said bending moment being exerted on said pair of pistons, and an opening formed in said stabilizing foot portion of said jackbody for receivng said toe portion of said lifting toe when in its lowermost position whereby to facilitate lifting objects disposed close to the ground or floor level.

10. A hydraulic jack cmprising, an upright body having a vertically disposed front wall 'and a forwardly projecting stablizing foot portion, a hydraulic fluid reservoir formed in the rear portion of said body, a pair of laterally spaced. vertically eX-tending cylinders formed in said body and being open at the top thereof, a pair of pistons disposed one in each of said cylinders and adapted to project above the top of said body when in their lowermost positions, a cross head connected between the upper ends of said pair of pistons and having a lifting surface on the top thereof, a vertically extending passage formed in said body midway between said pair of cylinders, a vertically extending slot formed in said front wall of said body, said slot opening into said vertically extending passage, a lifting toe characterized by a shank portion slidable in said passage and by a forwardly disposed toe portion having a horizontally disposed lifting surface and a vertically disposed rear surface which is slidably engageable with said front wall of said body, said toe portion being connected to the lower end of said shank portion by a narrow connecting portion which extends through said slot, means connecting the upper end of said shank portion to said cross head, a pump assembly mounted on the rear of said jack body, said pump assembly including a manually operable handle and passage means connecting the inlet of said pump assembly to said reservoir and the outlet of said pump assembly to the lower ends of said pair of cylinders whereby actuation of said pump handle is effective to direct hydraulic fiuid under pressure from said reservoir simultaneously to the lower ends of said pair of cylinders for raising said pair of pistons and said lifting toe connected thereto by said cross head, the bending moment resulting from said lifting surface of said toe portion being offset forwardly of said cylinders being absorbed by said jack body through the engagement of said rear surface of said toe portion with said front wall of said jack body whereby to prevent said bending moment being exerted on said pair of pistons, and an opening formed in said stabilizing foot portion of said jack body for receiving said toe portion of said lifting toe When in its lowermost position whereby to facilitate lifting objects disposed close to the ground or floor level.

ll. A hydraulic jack comprising, an upright body having a Vertical front wall and a forwardly projecting stabilizing foot portion, a pair of laterally spaced, vertically extending cylinders formed in said body and being open at the top thereof, a pair of pistons disposed one in each of said cylinders and adapted to project above the top of said body when in their lowermost positions, a cross head connected between the upper ends of said pair of pistons and having a lifting surface on the top thereof, a vertically extending passage formed in said body midway between said p'air of cylinders, said passage being square in horizontal cross-section, a ver-tically extending slot formed in said front wall of said jack body and intersecting said vertically eXtending square passage, a lifting toe characterized by an elongated square shank portion slidable in said vertically extending square passage and having its upper end secured in said cross head midway between the oonnections of the upper ends of said pair of pistons to said cross head, said lifting toe being further characterized by a toe portion having a horizontal lifting surface disposed forwardly of said front wall of said jack body, said toe portion being integrally connected to the lower end of said shank portion by a neck portion which extends through said slot, hydraulic means for directing hydraulic fiuid under pressure simultaneously to the lower ends of said pair of cylinders for raising said pair of pistons and said lifting toe connected thereto by said cross head, means for transmitting to said jack body lthe bending moment resulting from said lifting surface of said toe portion being disposed forwardly of the center line of said cylinders, an opening formed in said stabilizing foot portion of said jack body for receiving said toe portion of said lifting toe when in its lowermost position whereby to facilitate lifting objects disposed close to -the ground or floor level, a vertically extending rack for-mation on the rear surface of said square shank portion of said lifting toe, a Safety arm pivotally mounted on the rear surface of said jack body adjacent the top thereof for latching engagement with said rack formation whereby to prevent uncontrolled lowering of said lifting toe in the event of a hydraulic failure, and handle means on said jack body |to facilitate moving the jack from place to place.

12. A hydraulic jack as recited in claim 11 wherein said bending moment transmitting means comprises a roller carried on the lower end of said square shank portion of said lifting toe for engagement with the rear side of said vertically extending square passage formed in said jack body.

13. A hydraul'ic jack comprising, an upright body having a vertically disposed front Wall and a forwardly projec'ting stabilizing foot portion, a hydraulic fiuid reservoir formed in the rear portion of said body, a pair of laterally spaced, vertically extending cylinders fromed in said body and being open at the top thereof, a pair 'of pistons disposed one in each of said cylinders and adapted to project above the top of said body when in their lowermost positions, a cross head connected between fthe upper ends of said pair of pistons and having a lifting surface on the top thereof, a vertically extending passage formed in said body midway between said pair of cyiinders, said passage being square in horizontal cross-section, a vertically extending slot formed in said front Wall of said jack body, said slot opening into said vertically extending square passage, a lifting toe characterzed by an elongated square shank portion slidable in said vertically extending square passage and by a toe portion having a horizontal lifting surface disposed forwardly of said front wall of said jack body, said toe portion being integrally connected to the lower end of said shank portion by a narrow connecting portion which extends through said slot, means connecting the upper end of said shank portion to said cross head midway between the connections of the upper ends of said pair of pistons to said cross head, a pump assembly mounte'd on the rear of said jack body, said pump assembly including a manually operable handle and passage means connecting the inlet of said pump assembly to said reservoir and the outlet of said pump -assembly to the lower ends of said pair of eylinders Whereby actuation of said pump handle is cylinders for raising said pair of pistons and said lifting toe connected thereto by said cross head, said pump assembly having a manually operable release valve for controlled lowering of said pist-ons and said lifting toe, means for 'transmitting to said jack body the bending moment resulting from said lifting surface of said toe portion being offset forwaijdly of said cylinders, an opening formed in said stabilizing foot portion of said jack body for receiving said 'toe portion of said lifting toe when in its lowermost position whereby to facltate lifting objects disposed close to the ground or floor level, a vertically extending rack formed on the rear surface of said squ-are shank portion of said lifting toe, a Safety arm pivotally mounted on the rear surface of said jack 'body adjacent 'the top thereof 'for latching engagement with said rack whereby to prevent uncon'trolled lowering of said lifting toe in the event of a hydraulic failure, and handle means on said jack body to facilitate moving the jack from place to place.

14. A hydraulic jack as recited in clairn 13 wherein said bending moment transmi'tting means comprises a roller rotatably mounted in the lower end of said square shank portion of said lifting toe and on the rear portion thereof, said roller being in bending moment transmit'ting engagement with the rear side of said vertically extending square passage formed in said jack body.

References Cited in the file of this patent UNITED STATES PATENTS 1266358 Kiriyama May 21, 1918 1,751,056 Pfauser Mar. 18, 1930 2,163,959 Nilson June 27, 1939 2,469,67O Thompson May 10, 1949 2,508,240 Fenn May 16, 1950 2,592,168 Morris et al. Apr. 8, 1952

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