US2211479A - Hydraulic jack - Google Patents

Description

Agg. 13, 1940. n PoMERoY v2,211,479 A HYDRAULIC JACK Tm-rHY c.PoM nov ATTORVEYS I HYDRAULIC `mpx Filed Jah. 22. 19:58

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ATTORNEYS Aug. 13,

T. C. PQMEROY HYDRAULIC JAQK Filed Jan. 22. l1938 4 sheets-shan' '3 en"I al "sv F. csv' ATTORNEYS Patented Aug. 13, '1940 UNITED STATES- PATENT oFFiclE 4 Claims.

This invention relates to new and useful im'- provements in hydraulic jacks.

An object of the present invention is to. provide a hydraulic jack having means embodied in 5 the construction thereof, whereby it may be op erated in any position from a vertical to a horizontal position.

A further object is to provide a'jack of the I character disclosed comprising a pressure pump for forcing the uid beneath the piston to elevate the plunger, and having means associated with the pump for releasing the fluid from beneath the piston to permit the plunger to return to its normal, retracted position, and means being embodied in the operating handle of the pump for locking the handle in a position, whereby it cannot be operated to release the pressure fluid from beneath the piston. p A further object is to provide a hydraulic jack comprising a main cylinder, a reservoir, and an expansion tank, so interconnected that the fluid may be circulated. therebetween without the provision of air vents, as is now common practice in mostl uuid-operated Jacks.l v A further object is to provide a Jack of the character described including a cylinder having a load-engaging plunger mounted therein, and comprising a suitable pump for circulating fluid to and from the cylinder, saidpump having an operating handle which, when voperated in one direction, will force the fluid into the cylinder to elevate the plunger, and when 4operated in another direction, will actuate a. valve mechanism to release the'fiuid.

A further object of the invention is to provide a hydraulic jack comprising a cylinder, a reservoir, and an expansion tank .and in which the p expansion tank serves a dual purpose, in that when the plunger of the jack is lowered to its normal, or contracted position, the expansion tank acts to receive the overiiow from thereservoir, and when the jack is-operated to lift o load, a vacuum is createdY in the reservoir, which draws the liquid from the expansion tank into the reservoir, against'the force of` gravity, because of the circulatory connection between the expansion tankl and reservoir being at their .upper ends, and whereby the vacuum in the apparatus becomes greater, as the jack is operated to lift the load, which materially aids in sealing off the outside atmosphere from the liquid in the jack, because of the .vacuum tending to draw the packing glands of the jack into tighter contact with their respective parts.

- Features of the invention reside in .the means Y (Cl. Gli-52) provided' within the reservoir and expansion tank, whereby the jack may be operated in a horizontal position; in the pivotal support of the operating handle o! the pressure pump, whereby it is operated in substantially a vertical 5 plane to actuate the pump, and which supportpermits thehandle to be swung in substantially va horizontal plane to lock it against pumping movement, thereby to lock the piston of the pump against operation, whereby the danger of 10 the jack being accidentally released, when supporting a load, is eliminated; in the unique arrangement of the reservoir and the expansion tank on the base of the jack, whereby the means for supporting the pump handle may be `supl5 ported therebetween; inthe unique construction of the valve means provided in the lower portion of the pump for controlling the circulation of the fluid in the reservoir to and from the main cylinder, and whereby said valve means may be 20 conveniently unseated by relatively rotating the pump piston, thereby to permit the fluid to'return from the cylinder to the reservoir; and in the general construction and arrangement of the various parts of the apparatus. l 25 Other objects of the invention will appear from the following description and accompanying drawings and will be pointed out in the annexed claims.

In the accompanying drawings there has been 30 disclosed astructure designed to carry out the various objects of the invention, but it is to be understood that the invention is not conned to the exact features shown as various changes may lloe made within the scope of the claims which 35 follow.

In the drawings:

Figure l. is a vertical sectional view substantially on the line I-I oi Figure 3, showing the construction of the main cylinder and plunger 40 and the means for supporting theA operating handle on the base; l

Figure 2 is a. vertical sectional view substantially on the line 2--2 of Figure l, showing the means provided within the expansion tank and reservoir, whereby the jack may be operated in a horizontal position, or at any desired angle;

Figure 3 is a sectional planrview on the line 3-3 of Figure i, showing thearrangement of the main cylinder, expansion tank and reservoir on the pump base; y

Figure 4 is a detail sectional view on the line 4 4 of Figure 1, showing the valve means in normal closed position; l 5

Figure 5 is a similar view, but showing the pump piston actuated to open the valves;

Figure 6 is a detail sectional view on the line 6 6 of Figure 5;

Figure '7 is a plan view of the jack on a smaller scale, showing various positions of the operating handle of the pump;

Figure 8 is a view showing positions assumed by the iiexible tubes in the expansion tank and reservoir, when the jack is placed in a. horizontal position; and

Figure 9 is a detail sectional view on the line 9-9 of Figure l, showing the pivotal lsupport of the pump handle.

'Ihe novel jack herein disclosed is shown comprising a base, generally indicated by the numeral 2, preferably having a counterbore 3 therein, adapted to receive the lower end of a main cylinder 4. The lower end of the cylinder has secured therein a plug or closure member 5, having a depending cylindrical portion 6 adapted to be received in a relatively smaller counterbore 1, axially alined with the main cylinder.

The upper end of the cylinder is shown closed by means of a sealing member 8 having a conical surface 9 adapted to engage a correspondingly shaped seat II provided at the upper edge of the cylinder wall. 'I'he member 8 has an inwardly extending flange I2 bored to receive the plunger I3, which is tubular, as clearly illustrated in Figures 1 and 3. A suitable packing I4 is seated on the flange I2. A gland I5 is seated against the upper face of the packing I4 and is adapted to be forced downwardly by a cap I6, received in threaded engagement with the upper end of the cylinder, as clearly illustrated in Figure 1. The cap I 6 is bored to receive the reduced upper end I'I of the gland I 5, and the gland, in turnis bored to receive the plunger I3 and cooperates with the member I2 to guide the upper end of the plunger in its reciprocal movement. A load-engaging element I8 is fitted into the upper end of the plunger I3 and provides a cap therefor. The lifting element is provided with a threaded socket for receiving the upper end of a tie rod or bolt I9, the lower end of which is exteriorly threaded to receive a nut 2 l. I

A plunger head, generally indicated by the numeral 22, is secured to the lower end of the is seated against the bottom face of the member 23, and is preferably provided with a suitable retainer 25, of resilient material, for yieldably holding the peripheral flange of the packing 24 in sealing contact with the walls of the cylinder 4. A suitable washer 26 is interposed between the retainer and the nut 2l whereby the horl` zontal wall of the packing may be tightly clamped against the member 23 by rotation of the nut 2|.

A suitable relief valve 21 is provided in the lowermost end of the tie rod I9 of the plunger and is normally retained on,its seat by a suitable spring element 28, secured to the lower terminal of the rod I9 by suitable screws, as illustrated in Figure 1. A uid ductt29 leads from the valve 21 to a transverse opening 3l provided in the rod I9, immediately above the member 23. Suitable openings 32 are provided-in the wall of the plunger I 3 at its lower end and are alined with the opening 3l vin the rod I9.

An actuating bar 33 is received in the alined [openings 3| and 32, and has its ends disposed in close proximity to the walls of the cylinder 4. The actuating bar 33 rests upon the upper end of a pin 34, whose lower end engages the relief valve 2l. The means 28 for yieldably holding the relief valve 2I on its seat has suiiicient tension to overcome the weight of the actuating bar 33 and pin 24 so as to normally hold the valve 21 on its seat, as will readily be understood by reference to Figure 1. The purpose of the relief valve 2l willsubsequently be described.

-An important feature of the present invention resides in the iiuid retaining 'means of the jack which, as best illustrated in Figures 2 and 3, comprises a reservoir 35 and an expansion tank 36, interconnected at their upper ends by a suitable by-pass or cross duct 31, provided in a cap 38 preferably having annular grooves 39 in its lower face adapted to receive the upper edges of the expansion tank 35 and reservoir 35, as clearly illustrated in Figure 2. Suitable gaskets 4I are seated in the bottoms of the grooves 39 and are engaged by the upper ends of the expansion tank and reservoir to prevent leakage therebetween.

The lower ends of the reservoir and expansion tank 35 and 36 are shown seated on gaskets 42 supported in shallow counterbores provided in thebase 2. Suitable tie rods 43 are shown extending lengthwise through the expansion tank 36 and reservoir 35, and have their lower ends received in threaded engagement with thebase 2, as clearly illustrated at 44 in Figure 2. The upper ends of the tie rods 43 are received in apertures provided in the cap 38, and preferably have heads 45, whereby the rods 43 may be conveniently rotated to securely fasten the expansion tank and reservoir to thebase in leak-tight relation.

'The means for controlling the circulation of uid to and from the main cylinder is best illustrated in Figure 1, and comprises a pump, generally indicated by the numeral 4B. The pump comprises a cylinder 4l having a suitable base 48 tted to and secured to the base 2 of the jack by suitable bolts 49, best illustrated in Figures 4 and 5. 'Fne pump cylinder 41 has a piston 5I mounted for reciprocal movement therein, which projects from the upper end of the cylinder.

Leakage is prevented around the piston by a suitl able gland 52 and packing 53, receivedv in a counterbore 54 in the upper end of a cylinder and secured therein by a suitable cap 55, received in threaded engagement with the upper end of the cylinder 4l. A suitable locking nut 56 is also received in threaded engagement with the upper i end of the cylinder 4l. This nut secures the cap 55 in adjusted position, whereby the desired sealing engagement between the packing glands 52 and 53 and the piston 5I may be obtained.

Another feature of the invention resides in the novel construction of the valve means provided in the lower portion of the pump for controlling circulation of the iiuid therethrough. As best illustrated in Figures 4 and 5, the bore 5'I of the cylinder communicates at its lower end with oppositely disposed, axially alined valve chambers 58 and 59. A suitable check valve 6I is mounted 'in the valve chamber 58 and normally closes the upper end of a port 62. A spring 63 is preferably provided for constantly urging the valve 6I into engagement with its seat. The lower end of the port 62 communicates with one end of a horizontal duct 64, the opposite end of which' is in direct communication with one end of a exible intake tube 65, whose lower end is secured to the base 2 by a suitable fitting 66.

chamber 59 and its lower end with one end of va horizontal duct 13, whose opposite end is in direct communication with a duct 14. The duct 14 is connected at its opposite end to an annular passage 15, provided in the lower reduced portion 8 o1' the member 5 of the main cylinder 4. One or more transverse ducts 16 are provided in the reduced portion 6 of the lower end of the main cylinder, and are in direct communication with the annular channel 15 provided therein. A small duct 11 establishes communication between the transverse duct 16 and the counterbore 18, provided in the member 5 of the main cylinder. This counterbore is in communication with the lower end of the cylinder beneath the piston head 22, so that when fluid is pumped into the lower end of the cylinder beneath the head 22, the latter will beelevated, as will readily be understood.

Another feature of the invention resides in the means for operating the pump piston 5| and also, whereby said piston may be locked against axial movement to prevent lowering of the plunger I3,

when supporting a load. As shownin Figures 1 and 9,theupper end of the pump piston 5| is pivotally connected to a member or head 18, by a horizontally disposed pivot pin 88. An operating handle 8| is secured at Ione end to the member 19. A connecting element 83 has one end pivotally connected to the head 19 by a vertically disposed pivot pin 86. The axis of the pivot pin 86 intersects the axis of the pivot 88, and the-lat-` ter provides the axis about whichv the head 19 swings. The opposite end of the element 83 is preferably forked, as shown in Figures l and 9,

. and said forked end is pivotally connected to the vupper end of `an arm 84, by a horizontally disposed pin 98.` The lower end of the arm 84 is pivotally mounted on the base 2 of the jack substantially between the expansion tank 36 and reservoir 35, as clearly illustrated at 85.

The above described mechanism provides a'piv-y otal support for the handle 8| and also a locking means whereby the piston may be locked against rotary movement, thereby to prevent accidental actuation of the valve mechanism, ywhen the jack is supporting a load.v To thus lock the piston against rotary movement, the operating handle 8| is moved to an inclined position, either abo've or below the horizontal, as indicated by the dotted lines in Figure 1, whereby the handle cannot be swung to a lateral position, as shown in full and dotted lines in Figure '1, to relatively rotate the piston and thereby unseat the check valves 6| and 68.

Thus, it will be seen that the operatinglhandle .8| has the dual function of operating the piston 5| and also unseating the valves to release the iiuid from the lower end of the cylinder. This is a very desirable feature inthat it necessitates but a single operating member for performing these two functions.

To operate the pistonV 5|, the operating handlev 8| must be substantially in its intermediate or horizontal position, as shown in full lines in Figure 1 and the dotted lines C in Figure 7. When thus positioned', the axes of the pivots 88 and are disposed in parallel relation, whereby the head 19 of the handle and the connecting ele-A ment 83 may be oscillated about th'e axis of the pivot 98, as a single unit. By thus oscillating the head v19 .and element 83 about the axis of the. pivot 98, reciprocal movement is imparted to the piston 5|, as indicated bythe full and dotted lines in Figure 1. l

The above described locking means is, as pref viously stated, an important feature of the in- Another feature of th'e invention resides in`the.

means provided for actuating the valves 6| and 68 in the lower portion of the pump, whereby these valves may be forcibly unseated, thereby to permit the iiuid to return from the lower end of the cylinder beneath the piston head 22, to the reservoir 35.

To thus yopen the valves 36| and 68, a pair of thrust elements. 81 and 88A are mounted in the valve chambers 58 and 59, respectively, and each `normally has one end projecting into the bore 51 of-'the cylinder 41, as best illustrated in Figure 4. These thrust members are spring-actu-` ated, and are preferably tubular, as shown. Each has a suitable spring 89 mounted therein, and the inner ends of these springsiengage pins 9| secured in the adjacent ends of the thrust members, as best illustrated in Fi 4. The opposite ends of the springs 89 are seated against pins 92 having their terminals supported in a pair of fixed sleeves 93 and 98' of the valve chambers 58 and 59, respectively. The outward terminals of the thrust members 81 and 88 are preferablybeveled, as shown, whereby said ends may readily be inserted between the check valves and their respective seats, when the thrust members are moved in'opposite directions, by the lower end of the piston 5|, as will readily be understood by reference to Figure 6. The valve 6| is preferably opened slightly in advance of the valve 68.

As shown in Figures 4 and 6, the piston 5| has its lower end portion 94 flattened, whereby when the piston 5| is turned to the position shown in Figure 5, the thrust members 81 and 88 will be' thrust outwardly. When these members arethus thrust outwardly, their outer ends will engage the check valves 6| and 68 and unseat them, as clearly illustrated in Figure 5.. When the'` attened terminal 94 of the piston 5| is returned to its normal position, as shown in Figure 4, the thrust members 8 1 and 88 will return to their normal positions by the action of the springs 89,

and thus permit the valves- 6| and 68 to return to their respective seats, and thereby render the jack operative to pump fluid from the reservoir into the lower end of the cylinder 4 beneath the piston head 22. 3

Means is also provided for establishing communication between the upper end of the cylnder 4 and the lower end of the reservoir 35, and comprises a relatively small tube 95 having its upper end connected to the interior of the/cylinder 4 by a suitable tting 96. The lower end of the tube 95 has a suitable fitting 91 connecting it to one end of a horizontal duct 98 provided in the base 2 of the jack. The opposite end vof the duct 98 communicates with the lower end of the reservoir 35, as clearly illustrated in Figure 3.

A flexible tube |88 is provided within the expansion tank 36 and has its upper end secured voir 35 and the expansion tank 36. 'I'he lower end of the flexible tube Illil has a weighted head IUI whose lower end is disposed in close proximity to the bottom wall of the expansion tank, as best illustrated in Figure 2.

Before operating the jack, enough uid is introduced into the jack to completely ll the reservoir 35 and partially fill the expansion tank 35, when the plunger head 22 is in its lowermost position, as shown in Figure 1. The jack handle BI is then oscillated in substantially a vertical plane, whereupon iiuid. is drawn into the pump cylinder 41 from the reservoir 35 through the ducts 62 and 64. When the piston 5I is thrust downwardly, the iluid drawn into the pump cylinder through the valve 6I, is forced through the valve chamber 59, thereby unseating the valve 68. From the valve chamber 59, the iiuid ows through the ducts 12, 13 and 14, into the lower end of the main cylinder 4, as will readily be understood. Upon continued oscillation of the handle 8l, the fluid -will continue to flow into the lower end of the cylinder 4 beneath the plunger head 22, thereby causing the plunger I3 to elevate the load, until the operation of the pump is interrupted.

If the operator fails to cease pumping, whenv the plunger approaches the limit of its upward movement, the actuating bar 33, carried by the plunger, will subsequently engage the bottom surface of the member I2, whereby the bar 33 is moved downwardly relatively to the plunger, and thereby unseats the release valve 21. Such actuation of the release valve will permit the fluid pumped into the cylinder beneath the piston head 22, to by-pass or escape throughthe port 29 in the piston head, into the cylinder above the piston head, whence it returns to the reservoir 35, through the tube S5.

If the operator continues to oscillate the pump handle, a portion of the fluid returned to the reservoir may, when the reservoir is subsequently filled, by-pass over into the expansion tank through the horizontal duct 31 provided at the upper ends of the expansion tank and reservoir.

Fro'm the foregoing, it will readily be understood that the herein described jack is substantially fool-proof in operation, because, by the provision of the reservoir 35 and expansion tank 36, there is very little danger of the jack becoming `inoperative because of the lack of fluid pressure.

the jack, even when the Jack is supporting a heavy load.

'I'he ilexible tubes Il and |30 provided in the reservoir 35 and expansion tank 36, respectively, provide means whereby the jack may be operated at any angle, or in a horizontal position, as illustrated in Figure 8. In this figure, it will be seen that when the jack is placed in a horioi operating the pump, and unseating the valves zontal position, the tubes 65 and IIIII will bend or flex by gravity, whereby their weighted heads will rest upon the lowermost portions of the walls of the reservoir and expansion tank. There is suiicient oil in the reservoir so thatI the level 5 of the oil therein, when the jack is placed in a horizontal position, will be substantially above the head 61 of the intake tube E5. The flexible tubes 65 and |00, therefore, greatly extend the usefulness of the jack in that they make it possible toY operate the jack, when placed at an angle, or when in a horizontal position which, heretofore, has been impossible with hydraulic jacks of conventional construction.

'Ihe lower end of the fiexible tube IUD is disposed in close proximity to the bottom of the expansion tank, so that as the fluid is pumped from the reservoir into the lower end of the main cylinder, in the operation of elevating the plunger I3, a. portion of the uid in the expansion tank may be drawn upwardly through the tube |00 and into the reservoir by the vacuum which is created in the upper portion of the reservoir above the level of the fluid therein. The reservoir Aand expansion tank are so proportioned that there is ample room for the transfer of the uid therebetween and to and from the main cylinder, Without requiring the use of air vents. This is a very desirable feature in that it eliminates all danger of oil leakage from the jack, when not in use, regardless of the position of the jack.

It will be noted, as hereinbefore stated, that the operating handle BI has the dual function to permit the plunger to descend. The handle is also so arranged, that when in a certain position, it cannot be actuated to release the valves. When the handle is in its horizontal position, as shown in Figure 1, it may be swung laterally to either side, as shown in Figure 7, thereby to unseat the valves, as illustrated in Figure 6. When the operating handle is swung to an inclined position in its normal vertical path of travel, as indicated by the dotted lines in Figure 1, the valve mechanism cannot be released because of the angular relationship between the axes of the pivots 80 and 86, which prevents lateral swinging movement of the handle.

I claim as my invention:

1. In a hydraulic jack, a cylinder, a plunger therein having means for engaging an object to be lifted, a reservoir, an inelastic fluid, a pump for circulating fluid from the reservoir to the cylinder, said pump comprising a piston mounted for reciprocating movement within a suitable bore, check valves for the pump, an operating handle, a first pivot connecting said handle to the piston and having its axis disposed at sub-z stantially right angles to and intersecting the axis of the piston, a pivoted support having a portion overhanging the piston, the pivotal axis of said support being parallel to the axis of said iirst pivot, when the handle is in pumping position, a second pivot connecting said handle to the overhanging portion of said support, and substantially axially alined with the axis of the plston, whereby the handle may be swung out of its normal path of travel, and means on the piston for unseating said check valves to release the iluld in thecylinder, when the handle is moved f out of its normal path of travel.4

2. In an apparatus of the class described, a main cylinder having a plunger therein, a reservoir, an inelastic fluid, a pump for pumping iiuid from the reservoir to the cylinder tov elevate the ot connecting the handle to the'piston and having its aids substantially intersecting the axis of the v piston, a member mounted for swinging movement about a horizontally disposed supporting pivot, a vertical pivot connecting the handle opening elements adapted to be actuated to open to s`aid member and substantially axially alineda with the piston, said vertical and horizontal pivots being so related that when the horizontal pivots are in parallel relation, the handle maybe actuated to reciprocate 'the piston, and valve the valves, when the piston is relativelxmotated in said bore, whereby when said handle is swung out of its normal pathot travel about the axis of the vertical pivot, the check valves are unseated to release the fluid from the cylinder, said pivots also being so related to one another that when the handle is positioned at an angle with'respect to the horizontal, it cannot Ibe operated to unseat said passage to the cylinder, said pump comprising a bore having a piston therein provided with a suitable operating h'andle, said piston having a ilattened terminal adapted to be positioned between said valves, and thrust elements interposed 5 between said valves adapted to be engaged by said flattened terminal, when the piston is relatively rotated in said-bore, whereby said thrust elements are actuatedto unseat the valves and thereby permit the iluid to return from the cyl- 1o ',inder to the reservoir.

4. In a hydraulic jack, a base, a ,cylinder mounted thereon, a plunger within the cylinder having means for engaging a load, a'reservoir also mounted on the base-in substantially-parallel' l5 relation to the cylinder, a iluid passage connecting the lower end o1' the reservoir to the lower end of the cylinder, a pump comprising a bore having a piston mounted therein, a pair of check d valves in said passage for causing the iluid to 20 circulate from the reservoir to the cylinder,when` the pump is operated, said piston having a ilattened terminal, thrust elements in said passage between the valves having portions projecting into said bore, when the valves are engaged with 25 their respective seats, and means whereby said -piston may be relatively rotated in said bore,

whereby theilattened terminal thereof will engage said thrust elements and move them into engagement with said valves,'thereby tounseat 30 the valves and permit the iluid/infthe cylinder to return to the reservoir. 1 i

` TIMOTHY C. POMER.OY.

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