US2359060A - Jack structure - Google Patents

Description

. Sept. 26, 1944. E. sTRoM JACK STRUCTURE Filed NOV. v10,1941.

Patented Sept. 26, 1944 UNITED STATES PATENT OFFICE JACK STRUCTURE Ernest Strom, St. Paul, Minn., assignor to Vulcan Manufacturing Co., Inc., St. Paul, Minn., a corporation oi' Minnesota Application November 10, 1941, Serial No. 418,462

.6 Claims.

My present invention relates to a Jack structure of the hydraulic bumper type.

I One object of the invention is to provide a relatively light, yet powerful jack of this general character which is comparatively inexpensive to manufacture.

Another object is to provide a hydraulic jack structure having novel means for transferring oil from a reservoir to a lifting cylinder or from the cylinder back to the reservoir, such means including a partition member between the lifting cylinder and reservoir wherein a pump structure is located.

Still another object is to provide the partition member assembled by screwing of the reservoir into the lifting cylinder.

A further object is to provide an intake check valve 'in the partition member which is movable laterally and an outlet valve which is movable vertically, the pump plunger being coactible with both valves to move them'to an unseated position to permit return of oil when desired, screwthreaded means being provided to effect a ne adjustment of the valves for regulating the speed of return of the jack.

Still a further object is to provide a lifting hook on the jack structure which may be vertically adjusted to any one of several different positions by a simple lifting movement of the hook and sliding thereof along the lifting. cylinder to a position where a lug of the hook may enter a y desired one of Va plurality of spaced openings formed in a channel shaped member arranged longitudinally of the lifting cylinder.

Still a further object is to provide afoot member for the jack structure which may be formed of heavy sheet metal and secured to the jack by avcotter key or the like in such manner that the foot plate may be canted to an angular position to conserve space when storing the jack on the tool box or under a seat of the automobile.

With these and other objects inview; my invention consists in the construction; arrangement and combination of the various parts of my device whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed lout in my claims and illustrated in the accompanying drawing. Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give a full understanding of the invention both from its structural and functional standpoints. Accordingly, I have illustrated a preferred and desirable embodiment of the invention in the accompanying drawing, in which:

Figure 1 is a perspective view of a jack struc ture embodying my invention;

Figure 2 is an enlarged vertical sectional view with parts broken away to conserve space on the drawing;

Figure 3 is a sectional view on the line 3--3 of Figure 2, and

Figure 4 is a sectional View similar to the cenv tral portion of Figure 2, showing certain parts in a different position.

On the accompanying drawing, I have usedl the reference numeral I0 to indicate a foot plate. The plate lo may be Vpressed from heavy sheet metal, with a socket at' I3 and a plurality of depressions I6 adapted to bite into the ground when using the jack. The plate I0 also has a pair of groovelikc extensions I5 in opposite directions from the socket I3.

A stationary plunger I2 in the form of a tube or rod has a rounded lower end seated in the socket I3 and retained therein by a cotter pin I4. The axis of the pin I4 is crosswise relative to the grooves I5 so that when the jack is stored in the tool box or under the seat of the automobile, the foot plate may be tipped up to a position closely adjacent the plunger I2 to conserve space.

A lifting cylinder I'I surrounds the stationarll plunger I2 and is guided relative thereto by packing I8 and a guide ring I 9. The upper end of the lifting cylinder II has a partition member P seated therein and retained in its seated position by a reservoir 20. The reservoir 20 is threaded into the lifting cylinder II against va of the lifting cylinder. At the same time, packing 23 is compressed between the reservoir 20 and the upper end of the lifting cylinder` to eiect asealatilflifsptiii'li.v f ,1r

The partition member P has an intake valve seatmember- 24 screwed laterally into it. An intake check valve 25 of ball type is adapted to seat thereagainst under the bias of a spring 2S. An outlet check valve 21 is arranged to be normally seated against a. seat 28 of the partition member P by a spring 29. A cotter key 30 retains the spring 29 in position and also a follower washer 3la for the gasket washer 22.

- A pump cylinder 3I is provided in the form of a tube threadedly mounted in the upper end of packing 35 therein effect an oiltight seal. The upper end ofthe pump plunger is threaded into a fitting 36 which in turn is connected with a` cap 31. An actuating sleeve 33 is secured to the cap 31 as by a friction or press fit and a suitable welded connection after the parts are associated. A lock nut 3! is mounted on the pump plunger 32 to retain it in the fitting 38.

The fitting 36 has a coarse threaded exterior adapted to coact with threads in a boss 40 of the reservoir top 34. The reservoir has a nller plug at 4i and the actuating sleeve 33 has a vent opening at 42, the purpose of which will hereinafter be described. i

A lifting hook H is vertically adjustable with respect to the lifting cylinder i1. The hook H is formed on a loop member having a front part 43, side parts 44 and a rear part 45. The front part 43 is located at'a substantially lower elevation than the rearpart 45. The part 45 has a lug or projection 46 adapted to selectively enter any one of a plurality of openings 41 formed in a channel shaped member 43. The member 48 has its flanges shaped to fit the lifting cylinder I1 and suitably secured thereto as by spot welding, indicated at 49.

Practical Operation In the operation of my jack structure, the hook member H may be roughly adjusted to the desired elevation on the lifting cylinder I1 by tipping it upwardly as to the dotted position of Figure 2, vertically adjusting it, and at the desired height permitting the lug 46 to enter the opening 41 there found. The lifting hook may then be elevated by moving the cylinder i1 upwardly relative to the plunger i2, which is accomplished by actuating the pump plunger 32. On the upstroke, as shown in Figure 4, oil will be drawn in through the valve 25 from the reservoir 20 and into the pump cylinder 3|. On the down stroke, this oil closes the valve 25 and opens the valve 21 as it is displaced from the pump cylinder 3l and the vertical bore in the partition member P. The check valves will hold the load at any desired elevation.

When it is desirable to lower the Jael-:,the actuating sleeve 38 is pushed downwardly as far as it will go, which will result in the reduced end 33 of the plunger 32 almost touching the valve 25. The sleeve 38 is then rotated clockwise to cause the threaded tting 33 to rotate in the hub 40. This operation causes a relatively slow movement downward of the pump plunger 32, with plenty of leverage for causing the reduced end 33 to rst open the valve 25 by forcing it laterally and then finally opening the valve 21 by forcing it downwardly. The degree of opening of the valve 21 will determine the speed of descent of the jack and the speed can be nicely controlled by rotating the sleeve 33. When the threads 36 are right hand, then clockwise rota; tion of the sleeve 38 will lower the pump plunger 32 for the valve opening operation.

During the downward movement of the sleeve 38 as it is reciprocated, the air trapped therein may pass freely out through the vent 42. As the sleeve is moved upwardly, air passes freely in through the vent`42 so as to prevent any drag on the pumping operation. The illler plug 4i may be removed and additional oil placed in the reservoir 20 when necessary. Leakage of the oil from the jack is effectively prevented, however, the lower packing I8 and the upper packing aandoen K Some changes may be made in the construction and arrangement of the parts of my device without departing from the real spirit and pur pose of my invention, and it is my intention to cover by my claims any modified forms lof structure or use of mechanical equivalents which may be reasonably included within their scope withi out sacrificing any of the advantages thereof.

I claim as my invention:

1. In a Jack structure, a stationary plunger. a lifting cylinder telescopically mounted thereon, a reservoir screw threadedly mounted in and forming a continuation of said lifting cylinder, means for transferring fluid from said reservoir to said lifting cylinder comprising a partition member having a flange engaged by said reservoir as it is screwed into said lifting cylinder and thereby retained in position between the reservoir and lifting cylinder, a pump cylinder carried by said partition member, intake and outlet check valves in said partition member opening respectively from said reservoir and into said lifting cylinder, a pump plunger reciprocable in said pumfp cylinder, an actuator therefor comprising a sleeve connected with said pump plunger, said pump plunger extending through the top of said reservoir, said sleeve being telescopically mounted on said reservoir. said pump plunger being engageable with said intake valve to shift it of! its seatA and then with said outlet valve to shift it on its seat to permit return of oil through said outlet and intake valves from said lifting cylinder into said reservoir, and means to cause such engagement of said pumrp plunger with said valves.

2. In a jack structure, a stationary plunger, a lifting cylinder telescopically mounted thereon, a reservoir screw threadedly mounted on said lifting cylinder, means for transferring fluid from said reservoir to said lifting cylinder comprising a partition member confined between said reservoir and said lifting cylinder by their screw threaded connection, a pump cylinder carried 4by said partition member, intake and outlet check valves in said partition member opening respectively from said reservoir and into said lifting cylinder, said intake valve opening laterally and said outlet valve opening downwardly, a pump plunger reciprocable in said pump cylinder, and an actuator therefor comprising a sleeve connected with said pump plunger, said pump plunger extending throughA the top of said reservoir to said sleeve, said sleeve being telescopically mounted on said reservoir, said pump rplunger being engageable with said intake valve to shift it laterally oil' its seat and then, after passing said intake valve, beingl engageabie with said outlet valve to shift it downwardly oif its seat to permit return of oil through said outlet and intake valves.

3. In a jack structure, a stationary plunger, a lifting cylinder telescopically mounted on the upper end thereof, a reservoir separate from and mounted on said lifting cylinder, means for transferring fluid from said reservoir to said lifting cylinder comprising a partition member between said reservoir and said lifting cylinder, a pump cylinder carried by said partition member, intake and outlet check valves in said partition member opening respectively from said reservoir and into said lifting cylinder, and a pump plunger reciprocable in said pump cylinder and extending through the top of said reservoir, said pump plunger being engageable with Said intake valve to shift it on its seat and pass it and being then engageable with said outlet, valve to shift it off its seat to permit return of oil through said outlet and intake valves from said lifting cylinder into said reservoir, said plunger being smaller than the passageway between said valves to permit such return.

4. In a jack structure, a plunger, a lifting cylinder telescopically mounted thereon, a reservoir mounted on said lifting cylinder, means for transferring fluid from said reservoir to said lifting cylinder comprising a partition member between said reservoir and said lifting cylinder, a Ipump cylinder carried by said partition member, intake and outlet check valves in said partition member opening respectively from said reservoir and into said lifting cylinder, said intake valve opening laterally and said outlet valve opening downwardy, a pump plunger reciprocable in said pump cylinder, and an actuator therefore comprising a sleeve connected with said pump plunger, said pump plunger extending through the top of said reservoir to said sleeve, said plunger being engageable with said intake valve to shift it laterally off its seat and then with said outlet valve to shift it downwardly off its seat to permit return of oil through said outlet and intake valves.

5. A jack structure comprising a stationary plunger, a lifting cylinder telescoped thereon, a reservoir, pump and check valves to pump oil from said reservoir into said lifting cylinder upwardly at the hook end to unlock said lug. relative to an opening of said channel shaped.

element to permit longitudinal adjustment of the lifting hook thereon and coaction of said lug with another selected opening.

6. In a jack structure, a plunger, a lifting cylinder telescoped thereon, a reservoir, pump and check valves to pump oil from said reservoir into said lifting cylinder to displace said plunger therefrom, a lifting hook on said lifting cylinder comprising a loop portion encircling the lifting cylinder, a lug projecting inwardly from said loop portion, a supporting hook on said loop portion opposite said lug, and an elongated channel shaped element longitudinally arranged on said lifting cylinder with its flanges secured thereto and having spaced openings in its web to selectively receive said lug.

ERNEST S'I'ROM.

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