US2170029A - Hydraulic jack - Google Patents

Description

22, 1939. w. JILIDDELL ET AL 2,

HYDRAULIC JACK Filed Jan. 4'. 1937 HI g 1 25 i NVENTORS E Q 0" @151 I I ATTORNEY.

Patented Aug. 22, 1939 sTArEs PATENT OFFICE RAULIC JACK win ilamr. Liddell and Leander c. Morse,

Oakland, Calif.

Application January 4, 1937, Serial No. 118,945 5 Claims. (or. 60-52) This invention relates particularly to hydraulic jacks, although the method of operation outlined may be readily applied to any type of fluidoperated device in which a fluid is transferred 5 tical.

Another object of the invention is to provide a jack with means presenting the fluid in storage continuously to the intake of a transfer pump, irrespective of the relative position of the lack and pump.

A further object of the invention is to pro vide a valve system which will operate in proper sequence irrespective of the relative position of placement space in the container exactly equal to the instant volume of. fluid contained there- 0 in, irrespective of transfer of fluid to or from the container.

Other objects and advantages of the invention will become apparent as the following description is read on the drawing forming a part of this specification, and in which similar reference characters are used to designate similar parts throughout the several views, of which;

Fig. 1 is a sectional elevation through the invention.

0 Fig. 2 is a fragmentary view, shown partly in section, and showing the lower portion of the jack in reclined position, showing the fluid urged to the intake of the pump.

Fig. 3 is a modification of the invention show ,5 on a reduced scale.

. Fig. 4 is an enlarged fragmentary sectional view showing a modification of the follower in a self-acting type requiring no external urgence.

The usual hydraulic jack consists of a cylinder 0 and a lift operating therein,'a transfer-oil. storage, a pump for transferring oil between the cylinder'and storageand a valve-controlled bypass for releasing the lift.

These features are all included in this inven- .5 tion, the working cylinder being shown at "I,

the lift or piston at l l, oil storage cylinder or container at l2, the pump at l3, and valve-controlledbypass at M.

This invention resides in the method and. means for maintaining the oil supply IS in constant communication with the intake of the pump l3, irrespective of the relative position in which the jack is to be operated, such as the upright position shown in Fig. l, or reclined position shown in Fig. 2.

Thepiston ll hasaload engaging head I6, and is provided at its lower end I! with a leather cup packing I8 which is expanded to cooperate with the cylinder wall by means of a resilient expander l9, the packing l8 and expander'l9 being secured to the lower end of the piston or lift H by known means such as a washer and bolt 2!. A stop groove 22 is formed annularly the purpose of which will be later described.

This piston or lift i l is slidable in the cylinder l3, and the cylinder it has its upper and lower ends respectively secured in the container head 23 by threads 24%, and in the jack'base 25 by threads 26. f

The transfer-fluid or storage cylinder H2 is mounted concentrically about the working cylinder l0 and has its lower end secured to the jack base by threads 21, and its upper end retained by the shoulder 28 formed on the head 23.

The exterior periphery 29 of the working cylinder l0, and inner periphery of the'transferin the piston in spaced relation to its lower end,

fluid cylinder l2 are finished to slidably receive the follower which includes the ring or annu-.,

lar piston 3| which encompasses the working cylinder, and an annular cup leather packing 32 which cooperates with the respective walls 29 and and also encompasses the working cylinder.

A contracting resilient split ring 33 maintains the leg 34 of the cup leather 32 in contact with displacement space defined by the space 38 between the cylinders and betweenthe top39 of thebase and the cup leather packing 32, and

is sufilciently expansible, and exerts suflicient,

' urgence to lift or deliver all of the oil l5 except that contained in the passages and packing recess, to the intake 40 of the pump l3, in any position of the jack, either inverted, inclined, reclined or upright.

This follower may be constructed in such manner whereby no extraneous urgence is required, such as is illustrated in Fig. 4, in which the cup packing 32 and resilient contracting and expandmg rings 33 and 35 are duplicated on the upper side of the piston, in which the oil-contacting or lower packing prevents escape of fluid, and the air-contacting or upper packing prevents ingress of air.

With this self-acting follower, the follower can only 'follow or move with variations in the volume of oil in the container, since the air-contacting packing prevents admission of air. Thus the follower varies the displacementspace in the container in exact proportion to the variation in volume of oil in thecontainer.

The preferred embodiment however is shown in Fig, 1, in which the spring 31 maintains a constant pressure on the oil, making the cup packing more effective. I

To obviate any pomibility of the lift or piston ll being urged outwardly or dropping down out of the working cylinder I ll in inclined, reclined, or inverted position, a latch Al is mounted in the head 23 and cooperates with the annnular grooves 22 and 42 respectively in the projected and retractedpositions of the lift.

This latch is urged to cooperate with the respective grooves through the medium of a spring 43 and is retractable or releasable by means of the button 46 which is integral with the latch.

Thus, the piston may be forced down into the cylinder until-the latch ll catches in the groove 42, and when ready for operation, the button M is pulled outwardly, releasing the lift, after which the pump l3 may be brought into operation.

Similarly, when the lift reaches a predetermined projected-position, the latch will cooperate with the grooveZZ and prevent further movement. The piston may be removed from the cylinder by grimly releasing the latch and withdrawing the The pump it; has a piston 45 slidable Within the cylinder 46, the piston rod il slidably opersting through the gland 6t which is secured in or to the top of the cylinder. A lever ilt has one end pivoted in the bracket E3?) and is intermediately pivoted to the piston rod tl'i as shown at 5!, the handle extension of the lever being shown in end view at The intake connection to the pump is controlled by means of a valve urged by a spring 56 which is retained by a plug 5'5 which has a passage 55 communicating with the pump cyl-'- inder. The intake li? communicates with the chamber 33 through passages 5'? and 5d.

The pump discharge passage 5?: communicates with the space between the valve 53 and plug 55, and through passages 69 and M with the working cylinder it through a passage 62, which passage is controlled by a valve 53 which is urged moved, and also forms manually-controlled lowering means for the jack.

One side 69 of the base 25 is formed parallel to one side of the cylinder, so that the jack may be laid on its side for lateral or inclined operation.

Fig. 3 is a modification of the invention, in which the working cylinder l0 and storage cylinder 10 are mounted side by side, and they can also be mounted at right angles to each other, or in any other relative position, and still provide the same results. In this case, a cylindrical piston H is used with a cup leather packing 12, expander l3, Washer 14 and screw 15, both cylinders being mounted on the same base 16, which is otherwise formed similarly to the base 25, and includes the pump I 3, which for preservation of. space would obviously be mounted somewhat as indicated, back of, or in front of the pair of cylinders, the spring Tl being retained and seated against the head 18. In either type, the follower reduces the effective volume of the transfer storage in exact proportion to the fluid transferred therefrom, and increases the effective volume in exact proportion to the fluid tranferred thereto.

With operation of the jack in upright position, there is no appreciable difference over operation of other types of hydraulic jacks. However, in inclined, reclined, or inverted positions, the piston 3|, through urgence of spring 31, or with the structure shown in Fig. 4, without the urgence of a spring, continuously delivers oil to the intake 40 as is clearly illustrated in Fig. 2, the piston 3| functioning as a follower and varying the effective displacement volume of the transfer storage exactly in accordance with variations in the volume of stored fluid.

It will be understood that variations in construction and arrangement of parts, which variations are consistent with the appended claims, may be resorted to without detracting from the spirit or scope of the invention, or sacrificing any of the advantages thereof.

I claim:

1, In a hydraulic jack having a cylindrical lift having an annular groove formed adjacent the upper end thereof, a working cylinder, an encompassing transfer-fluid container, 2. supply of transfer fluid, and a pump having an intake; a spring-urged piston operating within said transfer-fluid container maintaining said supply of fluid continuously available to the intake of said pump irrespective of the position of said jack relative to its normal upright position, and latch means releasable at will and engageable with said groove for fixedly securing said lift when in fully retracted position against projectional movement under the influence of fluid urged by said spring-urged piston or by said pump or under. the influence of gravity when said jack is inclined, reclined or inverted.

2. A hydraulic jack comprising a base, a working cylinder and a lift operating therein, a concentric transfer cylinder having a pump-intake passage in communication with the lower end thereof, a fluid pump, a ring piston operating between said cylinders, and a spring urging said piston toward said lower end, delivering fluid through said passage when said jack is in an inclined, reclined, or inverted position; a groove formed adjacent each end of said lift, and alatch and manual releasing means therefor projection from its most retracted position in the working cylinder under the influence of gravity or urgence of said spring acting through said fluid or under the influence of pressure trans mitted through said fluid by said pump. 3. A hydraulic jack comprising a base, an operating cylinder secured to said base, a supply cylinder encompassing said operating cylinder'and secured to said base, a head common to both cylinders and secured to the top of said operating cylinder, a ringpiston operating between the walls of said operating cylinder and supply cylinder, a cup leather ring packing for the lower end of said'ring piston and resilient .15 expanding and contracting means respectively for the .respective vouter and inner peripheral walls of said ring packing, a spring urging said ring piston toward the bottom of said supply cylinder, anda lift piston operating in said opgo crating cylinder and having a cup leather packing aflixed to the lower end there'of and resillent expanding means for the annular wall of said cup'leather, said lift piston being normally urged for projection by said spring acting 25 through said fluid, a pump for transferring fluid from said supply cylinder tosaid operating cylinder, and a bypass between saidoperating cylinder and said supply cylinder and amanually controlled valve controlling said bypass and,

39 latch means associated with said head and cooperatively related to said lift piston, fixedly securing and locking said lift piston against projection from its most retracted position, under the urgence of fluid urged "either by said spring- 85 or by said, pump, and also against gravitational.

influences, and; manual releasing means for releasing said latching means at will.

4. A structure as claimed in claim 3, in'iwhich said latch means comprises'an annular groove 40 formed adjacent each end of said lift piston, and

a plunger associated with said head and spring urging means therefor, said manual releasing means being associated-with said plunger, said latching means being cooperatively related to 5 said grooves for retaining and locking said'opcrating piston against projection when said jack is inclined, reclined or inverted, against the influence of gravity or pressure applied through said fluid, and for stopping said operating piston against complete removal from said operating cylinder-said piston being freed for complete removal or for projection upon manual release of said latching means. 4 5. A hydraulic jack comprising a base, an operating cylinder threadedly secured on said base, i

.a supply cylinder encompassing said operating cylinder and forming an annular chamber therebetween, a ring piston operating in the annular chamber, a head threadedly securedto the top of said operating cylinder and having a shoulder securing the upper end of said supply cylinder and coaxially aligning said cylinders and permitting said head to be screwed onto said operating cylinder, a compression spring cooperating] and said pump and a bypass communicating between said operating cylinder and said annular chamber, a manually controlled valve for said bypass forcontrolling passage of fluid from said operating cylinder to said annular chamber at will, a square shouldered annular groove formed having a square face and reciprocally mounted in said head for cooperation with said grooves respectively for locking said lift piston when in completely retracted position against projection and in projected position against complete readjacent each end of said lift piston, a latch moval from said operating cylinder, a spring urging said latch to cooperate and manually controlled means associated with said latch for releasing said latch at will to free said lift piston for projection or complete removal. a

' WINGHAM J. LIDDELL,

l LEANDER, C. MORSE.

with said grooves,

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