US2393405A

US2393405A - Hydraulic lift jack

Info

Publication number: US2393405A
Application number: US493567A
Authority: US
Inventors: Herbert E Page
Original assignee: Individual
Current assignee: Individual
Priority date: 1943-07-05
Filing date: 1943-07-05
Publication date: 1946-01-22
Anticipated expiration: 1963-01-22

Description

Jan. 22, 1946. H. E. PAGE HYDRAULIC LIFT JACK Filed July 5, 1943 4 Sheets-Sheet l mig@ Jan. 22, 1946. H. E. PAGE 2,393,405 y HYDRAULIC LIFT JACK Filed July 5, 1945 4 Sheets-Sheet 2 :Wh: E26 130 l 151 156/ J; 155 125 141 l 127 130 s l S ',1315 l 128 J 1264 l /lz 154 I Ml 0 JNVENToR. 5 135]; I I l [gym-ef Jan. 22, 1946.` H. E. PAGE 2,393,405

HYDRAULIC LIFT JACK Filed July 5, 1943 4 sheets-sheet 5 Jan. 22, 1946. E PAGE 2,393,405

.HYDRAULIC LIFT JACK Filed July 5, 1945 4 Sheets-Sheet 4\ www 6'0 57 INVENToR.

' erZeTZEPag,

BY M

Patented Jan.22,. 1946 UNITED STATES PATENT OFFICE HYDRAULIC LIFT JACK Herbert E.'Page, Pasadena, Calif. Application July 5, 1943, serai N0.493,561 (ci. so-52) 'I'his invention relates to hydraulic pressureactuated devices and, in its more particular aspects, it relates to jacks. I'he invention has for one of its objects the provision of a jack in which the work-lifting member is rapidly -moved into contact with the work with minimum operation and without the application of fluid pressure.

Another object is to provide a jack of this character in whichthe fulcrum for the operating lever is raised to follow the movement of the work-lifting member.

Another object is the provision of a jack employing a telescopic piston andpermitting use of a relatively short cylinder.

A further objectv of my invention is the provision of a double-acting pressure-generating means.

A still further object is the provision of a highly simplified, durable jack lwhich may be manufactured with relative economy.

Additional advantages are inherent in my invention and how those, as well as the objects hereinabove particularly enumerated, are achieved will become apparent from the following detailed explanation of presently preferred adaptations illustrated in the accompanying drawings. I wish it understood, however, that in its broader aspects as dened by the accompanying claims, my invention is not to be conned tothe details of structure and association of parts illustrated in the drawings, since, with the understanding of the invention to be derived from the accomrpanying specification and drawings, various modifications and adaptations will occur to those skilled in the art.

In the accompanying drawings:

Fig. 1 is a vertical sectional view of one form of my invention taken on line of Fig. 2, some parts being shown in elevation;

Fig. 2 is a top plan View of Fig. l;

Fig. 3 is a medial Vertical sectional view showing a variational form of my invention;

Fig. 4 is a fragmentary vertical section showing a further variational form of the invention;

Fig. 5 is a perspective showing a further variational form of my invention; 5 Fig. 6 is a medial longitudinal section of Fig.

and Fig. 7 s a front elevation of Fig. 5.

Referring now to Figs'. 1 and 2, I show a body 5 in the interior of which I provide a relatively large cylinder 6 and a parallel` relatively small, cylinder 1, around which there is a hydraulic fluid reservoir 8 vented to atmosphere through port 9a in a threaded plug 9.

A work-lifting piston I0 is recprocally mounted in cylinder 6 and a pumping piston |2 is reciprocally mounted in cylinder 1. An operating lever l5 has one of its ends bifurcated and pivotally connected by pin I6 to the piston |0 and is fulcrumed on the flattened top end |2a of piston |2 by means of pin |1 and link I8.

Beneath the cylinders Iprovide in the body a valve-receiving bore 20 within whichI secure, as by snap ring 2|, a valve member generally designated 25. This valve member includes a body 26 having annular grooves to receive sealing rings 21. A poppet valve 30, having stems 3|, 32, is reciprocally mounted in the borev of a plug 33 threaded into one .end ofthe valve body, an annular sealing ring 34 being provided between the plug and body bore. Stem 3| is of squared crosssection to permit passage of fluid therearound. A second poppet valve 31, having a stem 38 and a bore 39, is reciprocally mounted in the valve body bore.` A coil spring40 seats at one end in the bore of a plug 42 threaded into the valve body bore and seats at its other end against poppet 31 to urge the latter against its seat. A spring 45 urges poppet 30 against its seat. Plug 42 carries a sealing ring 46. Valve member 25 has a reduced diameter portion providing an annular chamber 41V and a reduced diameter portion providing an annular chamber 48. A pull member 49 is provided on the outer end of the valve member 25. y A

Cylinder 1 communicates with the reservoir 8 through passageways 50, 5|, 52, said communication being controlled by poppet 30, cylinder 1 communicates with the cylinder 6 through

passageway

50, 52, 55, 54 and 53, and cylinder 6 communicates with the reservoir 8 through passage- Ways'53, 51, the latter of which is controlled by a spring-pressed ball check valve mounted in a chamber to which access is provided by a threaded rplug 60a. A cam 10 is mounted on a shaft 1| journaled in the body, the shaft having secured thereto exterior of the body an operating member 12 (Fig. 2).

To operate the device from the starting position shown in Fig l, the lever |5`is first lifted to move piston I2 outwardly of the cylinder, which causes a sufcient vacuum in cylinder 1 to unseat poppet 30 and draw hydraulic fluid into cylinder 1 through passageways 5|, 52 and 50. Then, upon downward pressure on the lever, it is fulcrumed about the pivot pin |1 and its left-hand end lifts piston ||l into engagement with the work to be engaged (not shown), there being insufficient resistance to movement of pis- .poppet 89 after cams |'I2 lift ton |`prior to contact with the lwork to cause poppet J1r to be unseated against the pressure of spring 40by such downward pressure on piston I2. This upward movement of piston I0 in its cylinder draws fluid into cylinder 6 from the reservoir through

passageways

53, 51. After piston I0 has thus contacted the work to be lifted, valve 60 ceases to function, but as the lever I5 is operated to impart the pumping strokes to piston I2, the resistance to upward movement of piston I0 caused by contact with the work is suiiicient to cause spring 40 to yield upon the pumping strokes of piston I2, permitting fluid to pass from cylinder 1 to cylinder 6. It will be observed that in operation of the lever, the fulcrum point alternately shifts from one piston to the other until piston |0 contacts the work, and is raised in consonance with elevation of the piston I0.

When it is desired to lower the work, member 12 is rotated to rotate shaft 1| and cam 10, the latter contacting the stem 3| to iirst unseat poppet 30 and release pressure in cylinder 1. Further inward movement of the stem 3| causes stem 32 to contact stem 38 and' unseat poppet 31 to release the pressure in cylinder 6.

In practice, spring 40 is proportioned in strength to the resistance normally to be offered to movement of the piston I0 when that piston is not burdened by any load to be lifted. Thus poppet 31 will remain seated until spring 40 yields under the pressure of the pumping stroke of piston I2 after piston I0 contacts the load. Spring 45 is preferably made relatively weaker than spring 40 to permit it to yield upon the suction stroke of piston I2.

In the variational form of my invention shown in Fig. 3, I show a body 80 having a relatively large medial cylinder 8| and a pair of relatively smaller cylinders 82, 82a disposed one on each side of the larger cylinder. A hydraulic fluid reservoir 85 surrounds the cylinders and is in communication therewith through

ports

86, 81, 88 controlled respectively by check valves 89, 90, 9|, which valves seat towards the reservoir.

A work-lifting piston 95 having a work-engaging top end portion 95a is reciprocally mounted in cylinder 8|, and pumping pistons 96, 96a are reciprocally mounted respectively in cylinders 82, 82a.

An operating handle 91 has avmedial portion 'encompassing and pivotally connected to piston respective cylinders B2, 82a. is established by ports 99, |00, respectively, said ports being controlled by coaxial poppet valves |0I, |02, respectively, whose inner ends are spaced apart, the valves being urged into seating position towards the respective cylinders 82, 82a by coil spring |03. The reservoir 85 is vented. to atmosphere by means of ports |05 provided in threaded plugs |06. For actuating valves 8,9, 90, 9| in the manner to be hereinafter described, I provide a shaft |08 journaled adjacent one end in-one side of the body and journaled adjacent its other end in a bearing plug |09 threadedly mounted in the body. Three longitudinally spaced eccentric cams ||0, III, ||2 are secured on the shaft in such relative position that cam I I0 will lift poppets 90, 9| upon rotation of the shaft.

Up and down movement of the respective ends of the lever, pivoting about pin- 91a, causes fluid to be alternately drawn into the cylinders 82, 82a past the respective valves 90, 9| and progressively lifts the piston 95 until it contacts the work to be lifted, drawing fluid into cylinder 8| past valve 09.

After the load has thus been contacted by the piston 95, each subsequent downward stroke of the respective pistons 96, 96a forces fluid past the respective valves IOI, |02 into cylinder 8| to raise piston 95 hydraulically. Spring |08 is strong enough to prevent either of the valves |0I, |02 from unseating prior to the time piston 95 contacts the work to be lifted. Of course, as piston 95 is thus progressively raised, the fulcrum points for lever 91 are commensurately raised.

When it is desired to lower the load, handle I I5 is operated to rotate shaft |08 and rst bring the cams I I I, ||2 into lifting engagement with poppets 90, 9| and then to bring cam ||0 into lifting engagement with poppet 89, to release the pressure in the various cylinders.

In Fig. 4 I show a further variational form of device incorporating the feature of telescopic pistons. Here the valve and port structures are as before described, the body being divided into upper section |25 and lower section |25a. A pair of cylinders |26, |21 and a uid reservoir |28 are provided in the body, the reservoir being vented to atmosphere through port |29.

Telescopic pistons generally designated by the numerals |30, `|3I are mounted in cylinders |26 and I 21, respectively. Piston |30 comprises an outer portion |a and an inner portion |30b reciprocally mounted in said outer portion. Piston portion |30a has an enlarged diameter inner end providing an upwardly facing stop shoulder |35 engageable against shoulder '|36 provided by threaded plug |25b; and inner piston portion |30b has an enlarged diameter inner end providing an upwardly facing stop shoulder |40 which is engageable against shoulder |4| provided adjacent the top end of the bore of piston portion |30a, both said stops being to limit upward movement of the piston portions. Transversely through the side wall of piston portion |30a adjacent the top end I provide holes |43 slidably carrying detent pins |44 whose rounded inner ends are normally urged into the annular recess |41 in piston portion |3017 by means of a spring |45 fitting in grooves in outer ends of the pins. The top end of piston |3017 carries a sleeve |30c which presents a downwardly facing annular shoulder |46 seating against top end of,4 piston I30a when the device is fully telescoped.

said pins being yieldingly urged inwardly by spring |64.

An operating lever |16 vhas a bifurcated inner end pivotally mounted on the upper end of piston portion |30b and is fulcrumed atop a link |11 carried by the upper end of piston portion 3| b. Pins |18 secure the leve'r to the link and Athe link to the piston.

stem 3|. Also, the body is mounted in a flanged base |82, and to provide access tothe valve housing 26 the body has a detachable plate |80a and the base flange has a detachable plate I82a.

Here the operating lever |83 has two arms |83a, |83b whose inner ends are bifurcated to receive the respective downwardly disposed arms |8||a of a yoke 84,. being pivotally connected to the arms by pins |85. Yoke |84 is secured to the upper end'of piston l'by cross pin |86. .Piston I2 is operatively secured to the arms |83a, |83b by links |81a, pivotally secured at one end to a yoke |81 and pivotally secured at their other ends to arms |83a, |83b, respectively. Yoke |81 is secured to the projecting end of piston I2 by cross pin |90.

The operation of the device of Figs. 5-7 is like that of Figs. 1 and 2 except that the operating lever is operated from a lower plane so as to be further removed from the work being lifted.

I claim:

' 1. In a hydraulic jack, the combination of a body presenting a pair of cylinders `and a fluid reservoir, a pumping piston reciprocally mounted inthe first cylinder and projecting therefrom,`

a work piston reciprocally mounted in the second cylinder and projecting therefrom, said body presenting a rst fluid passageway ccmmunicating with the reservoirand the first cylinder and a second fluid passageway establishing communication between the first and second cylinders, a check valve in the first fluid passageway seating towards the reservoir, said valve being moving towards the first cylinder, a spring urging the last-named valve into seating' position, saidv spring being yieldable to fluid pressure created Iby the'pumping stroke of the pumping piston only when the work piston is burdened with a work load, an operating lever pivotally connected at spaced points therealong to the projecting ends of the respective pistons, said lever, when fulcrumed on its said pivotal connection to the pumping piston, functioning to move the work piston towards engagement with vthe work independently of any fluid pressure in the second cylinder, a third fluid passageway in the body establishing communication between the reservoir and the second cylinder through which fluid nication between the first and second cylinders, `l

a self-closing check valve in the first fluid passageway seating towards the reservoir, said valve being movable off its seat by vacuum created by the suction stroke of the pumping piston whereby fluid is drawn from the reservoir into the first cylinder, a check valve in the second passageway seating towards the first cylinder, said lastnamed valve |being movable off its seat by fluid pressure created by the pumping stroke of the pumping piston only when the work piston is burdened with a work load, an operating lever pivotally connected at spaced points therealong to the projecting ends of the respective pistons, said lever, when fulcrumed on the pumping piston, functioning to move the work piston towards engagement with the work independently of any fluid pressure in the second cylinder, means responsive to vacuum in the second cylinder to pass fluid thereto from the reservoir when the work piston is being so moved towards engagement with the work, and means for releasing fluid pressure in the cylinders including a valve unseating member.

3. In a jack, the combination of a body pre- 'senting a work cylinder and a pair of pump cylinders one on each side of the work cylinder, a fluid reservoir, fluid passageways establishing communication between the respective pump cylinders and the reservoir, a self-closing check valve in each passageway seating towards the reservoir, ports in the body establishing communication between the work cylinder and the respective pump cylinders, check valves controlling the respective ports and seating towards the respective pump cylinders, a work-lifting piston reciprocally mounted in the work cylinder, spring means cooperating with the last-named check valves to maintain them seated when the worklifting piston is not under load, a pumping piston reciprocally mounted in each pump cylinder, a lever pivotally connected at spaced points therealong to each of the respective pistons and means responsive to vacuum in the work cylinder to pass fluid thereto from the reservoir, said means including a fluid passageway in the body and a self-closing check valve therein seating towards the reservoir. y

4. In a hydraulic jack, the combination of a body presenting a pair of cylinders and a fluid reservoir, a pumping piston reciprocally mounted in the first cylinder and projecting therefrom. a work piston reciprocally mounted in the second cylinder and projecting therefrom, said :body presenting a first iiuid passageway communicating with the reservoir and the first cylinder and a second fluid passageway establishing communication between the first and second cylinders, a check valve in the first fluid passageway seating towards the reservoir, said valve being unseatable by vacuum created by the suction stroke of the pumping piston whereby iiuid is drawn from the reservoir into the iirst cylinder, a check valve in the second passageway seating towards the first cylinder, a spring urging the last-named valve into seating position, said spring being sufficiently strong as to be yieldable to fluid pressure created :by the pumping stroke of the pumping piston only when the work piston is burdened with a work load, an operating lever pivotally connected at spaced points therealong to the projecting ends of the respective pistons, said lever, when fulcrumed on the pumping piston, functioning to move the work piston towards engagement with the work independently of any fluid pressure in the second cylinder, means for releasing iiuid pressure in the cylinders including a valve unseating member, a fluid passageway in the body establishing communication between the work cylinder and reservoir, a check valve Icontrolling said passageway and seating towards the reservoir, and cam means engageable against said last-named valve in a manner to unseat the valve.

spring load on the last-named check valve being sufficient to maintain it seated when the piston mounted in said work cylinder is not under load, an operating lever pivotally secured at spaced points therealong to the respective pistons whereby downward movement of one end of the lever fulcrums the lever on one of the pistons and I exerts a lifting force on the other piston, a third passageway in the body providing communication from the reservoir to the work cylinder, and a self-seating check valve seating towards the reservoir in the third passageway.

,6. In a jack, the combination of a body presenting a fluid reservoir and a pair of cylinders, a work piston reciprocally mounted in the second cylinder and a pumping piston reciprocally mounted in the first cylinder, self-closing check valve means operable in response to vacuum in the rst cylinder to pass fluid thereto from the reservoir, a fluid communication passageway between the cylinders, a check valve' in the passageway seating towards the first cylinder, the spring load on the last-named valve being sufficient to maintain said valve seated when the work piston is not under load, each of said pistons comprising an outer sleeve portion, inter-engaging means in the cylinder and sleeve operable to limit outward movement of the sleeve relative to the cylinder, an inner member slidably mounted in the sleeve portion, yieldable detent means on the sleeve engageable against the inner member vwhereby to oppose movement of the inner member relative to the sleeve, an operating lever pivotally connected at points spaced longitudinally thereof to the inner members of the respective pistons, and means responsive to vacuum in the second cylinder topass fluid thereto from the reservoir, said last-named means including a fluid passageway in the body and a self-closing check valve in said passageway seating towards the reservoir.

7. In a jack, the combination o-f a body presenting a fluid reservoir, a pumping cylinder and a work cylinder, a pumping piston reciprocally mounted in the pumping cylinder, a work piston reciprocally mounted in the work cylinder, selfclosing check valve means operable in response to vacuum in the pumping cylinder to pass fluid ,thereto from the reservoir, a iiuid communication passageway in the body providing communication between the cylinders, a check valve in the passageway seating towards the pumping cylinder, spring means for maintaining the lastnamed valve seated when the work piston is not under load, each piston having a portion projecting upwardly beyond the body, links pivotally connected at their top ends to the projecting portions of the respective pistons and being [disposed downwardly therefrom, an operating lever pivotally connected to the lower ends of the ,respective links at points spaced apart longitudinally of the lever, and self-closing means responsive to vacuum in the work cylinder to pass fluid ,thereto from the reservoir.

HERBERT E. PAGE.