US2322314A - Hydraulic jack - Google Patents

Description

- T. C. POMEROY HYDRAULIC JAcK Original Filed ,Jan. 22, 1938 June 22, 1943.

4 Sheets-Sheet 1 ATTozNEYs E 0 m m June 22, 1943. 1', c, PQMEROY 2,322,314

HYDRAULIC JACK Original Filed Jan. 22, 1938 4 Sheets-Sheet 3 El/OIE ION TANK 777///% I AVA/A /NVENTOE 77Mo7-HY C. POMEEOY Arron/vs Y:

June 22, 1943. T. c. POMEROY HYDRAULIC JACK Original Filed Ja n.- 22, 1938 4 Sheets-Sheet 4 77Mb'r/1Y Patented June 22, 1943 HYDRAULIC JACK Timothy C. Pomeroy, Long Beach, Calif.

Original application January 22, 1938, Serial No. 186,366, new Patent No. 2,211,479, dated August 13, 194i). Divided and this application July 5, 1940, Serial No. 343,928

1 Claim. (01. 60- 52) This invention relates to new and useful improvements in hydraulic jacks, and is a division of my pending application, Serial No. 186,366, now Patent No. 2,211,479.

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

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 most fluid-operated jacks,

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 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 overflow from the reservoir, andwhen the jack is operated to lift a load, a vacuum is created 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 tank 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 flexible conduits provided in the expansion tank and reservoir, having weighted heads at their free, unsupported ends adapted to bend said conduits, when the jack is supported at an incline or in a horizontal position, whereby the intake ends of said conduits will be disposed below the level of the liquid in said tank and reservoir, when the jack is supported on its side, or in substanmany a horizontal position; in the provision of a hydraulic jack comprising a reservoir and an expansion tank, neither one of which is provided with a vent opening, whereby the jack may be placed on its side without danger of the liquid leaking therefrom; and, in the provision of a hydraulic, leak-proof jack of simple and inexpensive construction.

Other objects of the invention will appear from the following description and accompanying drawings and will be pointed out in the annexed claim.

--In the accompanying drawings there has been disclosed a structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown as various changes may be made within the scope of the claim which follows.

In the drawings:

Figure 1 is a vertical sectional view substantially on the line I-| of Figure 3, showing the construction of the main cylinder and plunger and the means for supporting the operating handle on the base;

Figure 2 is a vertical sectional View substantially-on the line 22 of Figure 1, 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 plan view on the line 33 of Figure 1, showing the arrangement of the main cylinder, expansion tank and reservoir on the pump base;

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

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; and

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

The 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 ll provided at the upper edge of the cylinder wall. The member 8 has an inwardly extending flange l2 bored to receive the plunger 13, which is tubular, as clearly illustrated in Figures '1 and 3. A suitable packing l4 is seated on the flange l2. A gland I5 is seated against the upper face of the packing l4 and is adapted to be forced downwardly by a cap [6, received in threaded engagement with the upper end of the cylinder, as clearly illustrated in Figure 1. The cap I6 is bored to receive the reduced upper end ll of the gland I5, and the gland, in turn, is bored to receive the plunger I3 and cooperates with the member l2 to guide the upper end of the plunger in its reciprocal movement.

A load-engaging element 18 is fitted into the upper end of the plunger [3 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 IS, the lower end of which is exteriorly threaded to receive a nut 2|.

A plunger head, generally indicated by the numeral 22, is secured to the lower end of the plunger l3, and is shown comprising a disk-like member preferably having a shallow counterbore in its upper surface for receiving the lower end of the plunger 13. A cup-shaped packing 24 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 2!, whereby the horizontal 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 IQ of the plunger and is normally retained on its seat by a suitable spring element 28, secured to the lower terminal of the rod [9 by suitable screws, as illustrated in Figure 1. A fluid duct 29 leads from the valve 2? to a transverse opening 3| provided in the rod l8, immediately above the member 23. Suitable openings 32 are provided in the Wall of the plunger 3 at its lower end and are alined with the opening 3| in the rod 19. V

An actuating bar 33 is received in the alined openings 3i 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 21'. The means 28 for yieldably holding the relief valve 2'! on its seat has sufficient 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 l. The purpose of the relief valve 21 will subsequently be described.

An important feature of the present invention resides in the fluid 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 ends of the expansion tank 36 and reservoir 35, as clearly illustrated in Figure 2. Suitable gaskets 4| 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 the base 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 the base 2,

iii!

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 the base in leak-tight relation.

The means for controlling the circulation of fluid to an from the main cylinder is best illustrated in Figure l, and comprises a pump, enerally indicated by the numeral 46. The pump comprises a cylinder 4? having a suitable base 48 fitted to and secured tothe base 2 of the jack by suitable bolts 49, best illustrated in Figures 4 and 5. The pump cylinder 47 has a piston 5| mounted for reciprocal movement therein, which projects from the upper end of the cylinder. Leakage is prevented around the piston by a suitable gland 52 and packing 53, received 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 41. A suitable locking nut 56 is also received in threaded engagement with the upper end of the cylinder 4?. This nut secures the cap in adjusted position, whereby the desired sealing engagement between the packing glands 52 and 53 and the piston 55 may be obtained.

Means is provided in the lower portion of the pump for controlling circulation of the fluid therethrough. As best illustrated in Figures 4 and 5, the bore 5'! of the cylinder communicates at its lower end with oppositely disposed, axially alined valve chambers 58 and 59. A suitable check valve 6| is mounted in the valve chamber 58 and normall closes the upper end of a port 32. A spring 63 is preferably provided for constantly urging the valve 6| 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 flexible intake tube 65, whose lower end is secured to the base 2 by a suitable fitting 65. The flexible tube 65 extends upwardly into the reservoir 35 and has a weighted head 61, the upper end of which terminates at or near the intermediate portion of the reservoir 35. The flexible tube 65 forms an important part of the present invention, as will be susequently described.

A check valve 68 is also provided in the valve chamber 59, and is normally engaged with a seat 69 by a suitable spring 1 I. A vertical duct 12 has its upper end communicating with the valve chamber 59 and its lower end with one end of a 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 6 of 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 be elevated, as will readily be understood.

Means is provided for operating the pump piston 5| and also, whereby said piston may be locked against axial movement to prevent lowering of the plunger l3, when supporting a load. As

shown in Figure 1, the upper end of the pump piston is pivotally connected to a member or head 19, by a horizontally disposed pivot pin '85 An operating handle 8| is secured at one 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 80, and the latter provides the axis about which the head 79 swings. The opposite end of the element 83 is preferably forked, as shown in Figures 1 and 2, and said forked end is pivotally connected to the upper end of an arm 84, by a hori zontally disposed pin 90. 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 pivotal 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, when the jack is supporting a load. To thus lock the piston against rotary movement, the operating handle Bl is moved to an inclined position, either above or below the horizontal, as indicated by the dotted lines in Figure 1, whereby the handle cannot be swung toa lateral position, as shown in full and dotted lines in Figure '7, to relatively rotate the piston and thereby unseat the check Thus, it will be seen that the operating handle 8| has the dual function of operating the piston -5| and also unseating the valves to release the fluid from the lower end of the cylinder.

This is a Very desirable feature in that it necessitates but a single operating member for performing these two functions.

. To operate the piston 5|, the operating handle 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 as and 90 because of the fluid accidentally being released from the lower end of the cylinder 4. If desired, suitable means, not shown, may be provided for positively securing the handle in looking position.

Means is 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 fluid to return from the lower end of the cylinder beneath the piston head 22, to the reservoir 35.

To thus open the valves BI and 68, a pair of thrust elements 87 and 88 are mounted in the valv chambers 58 and 59, respectively, and each normally has one end projectin into the bore 51 of the cylinder 41, as best illustrated in Figure 4;. These thrust members are spring-actuated, and are preferably tubular, as shown. Each has a suitable spring 89 mounted therein, and the inner ends of these springs engage pins 9| secured in the adjacent ends of the thrust members, as best illustrated in Figure 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 9B of the valve chambers 58 and 59, respectively. The outward terminals of the thrust members 8'! and 88 are preferably beveled, 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 BI 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 9 1 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 are thus thrust outwardly, their outer ends will engage the check valves 6| and 58 and unseat them, as clearly illustrated in Figure 5.

-When the flattened terminal 94 of the piston 5| is returned to its normal position, as shown in Figure 4, the thrust members 8'! 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 pump operative to pump fluid from the reservoir into the lower end of the cylinder 4 beneath the piston head 22.

Means is also provided for establishing communication between the upper end of the cylinder 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 fitting 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 of the duct 98 communicates with the lower end of the reservoir 35, as clearly illustrated in Figure 3.

Another feature of the invention resides in the provision of a flexible tube I00 within the expansion tank 35, which has its upper end secured to the head 38 by a suitable fitting 99. This fitting is in direct communication with the by-pass 31 in the head 38, which establishes communication between the interiors of the reservoir 35 and the expansion tank 36. The lower end of the flexible tube lilii has a weighted head ||l| 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 fluid is introduced into the jack to completely fill the reservoir 35 and partially fill the expansion tank 36, when the plunger head 22 is in its lowermost position, as shown in Figure 1. The jack handle 8| is then oscillated in substantially a vertical plane, whereupon fluid is drawn into the pump cylinder 41 from the reservoir 35 through the ducts 62 and 54. When the piston 5| is thrust downwardly, the fluid drawn into the pump cylinder through the valve BI is forced through the valve chamber 59, thereby unseating the valve 68. From the valve chamber 59, the fluid flows through the ducts l2, l3 and 14, into the lower end of the main cylinder 4, as will readily be understood. Upon continued oscillation of the handle 8|, the fluid will continue to flow into the lower end of the cylinder 4 beneath the plunger head 22, thereby causing the plunger l3 to elevate the load, until the operation of the pump is interrupted.

If the operator fails to cease pumping, when 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 through the port 29 in the piston head, into the cylinder above the piston head, whence it returns to the reservoir 35, through the tube 95.

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.

From 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, There is always enough fluid in the apparatus to assure eflicient operation thereof provided, of course, that the fluid contained in the jack does not escape or leak therefrom.

Leakage of the liquid from the apparatus is sub stantially eliminated as a result of the vacuum which is created in the apparatus, when the jack is operated to elevate a load. This vacuum becomes greater as the jack is operated to lift the load, and thereby tends to draw the packing glands into tighter sealing engagement with their respective parts, whereby the liquid cannot escape from the jack, even when the jack is sup porting a heavy load.

The flexible tubes 65 and I provided in the reservoir 35 and expansion tank 36, respectively, provide means whereby the jack maybe 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 hori zontal position, the tubes 55 and I00 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 suflicient oil in the reservoir so that the level of the oil therein, when the jack is placed in a horizontal position, will be substantially above the head 61 of the intake tube 65.

The flexible tubes 65 and I00, therefore, greatly extend the usefulness of the jack in that they make it possible to 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.

The lower end of the flexible tube I00 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 fluid in the expansion tank may be drawn upwardly through the tube I00 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 and expansion tank are so proportioned that there is ample room for the transfer of the fluid therebetween and to and from the main In a hydraulic jack, a cylinder, a plunger therein, an inelastic fluid, a reservoir, a valved passage connecting the bottom of reservoir to the cylinder, an expansion tank disposed adjacent to the reservoir, a fluid passage connecting the upper ends of the reservoir and expansion tank, a pump for pumping fluid from the reservoir through the valved passage to the cylinder to elevate the plunger, the intake of said valved passage having one end of a flexible tube connected thereto, said tube being mounted in the bottom of the reservoir and extending upwardly therein and having a weighted head, whereby the tube will flex or bend when the jack is placed in an inclined or horizontal position, thereby to retain the intake end of said flexible tube beneath the level of the fluid in the reservoir, and the fluid passage connecting the upper ends of the reservoir and expansion tank having a flexible tube connected thereto and extending -downwardly into the expansion tank with its

Images