sept-17, 1946. ' 2,407,796 H. E. PAGE TRIPOD JACK Filed Aug. 17, 1945 ` 2 Sheets-Sheet l O 76 .Js _.1.J ü ,Q _b „ ,_ „_ „__ w n a ìwî2lœ5îi:l 3 M_# w _w «m _a_ nœ _ l\ _ _ WW/.v _.lVm 777m n, _w ÍÉ._8 m.ladìfMw îEzn xM|ì_ß»EL._+ANN:œ\wJ\s\a\ _ l_wp ./|V Èë 2„R @T ,m _ ._ _ j MÈ _._ „y ß2» r„L ëw “ M _ .9 l__ __ w __ _ n _ __ _ Sept. 17, 1946. H. E. PAGE TRIPOD JACK Filed Aug. 17, 1943 ~2,407,796 _ 2 Sheets-Sheet 2 Patented Sept. 17, f1946 2,407,796 UNITED STATES PATENT OFFICE 2,407,796 TRIPOD JACK _ Herbert E. Page, Pasadena, Calif. Y Application August 17, 1943, Serial No. 498,930 13 Claims. (Cl. 60-52) 1 2 This invention has to do with jacks and, more which latter provides a fulcrum for the pumping particularly, it relates to hydraulically actuated lever 2li. A tubular guide member 25 has its tripod jacks such as are used for raising loads lower end threaded into the socket I'l and pre to substantial heights. Although such jacks have sents a cylinder 26. Threaded filling plug 21 is many uses, oney of the chief uses is as an air 5 provided for reservoir I2. plane jack. A body 3D presents a cylinder bore 32 and a While tripod jacks are known in the art, here relatively larger cylinder bore 33. Within the top tofore they have had certain inherent shortcom end of bore 33 there is a threaded sleeve 35 within ings such as lack of proper rigidity, limitations of which is slidably >mounted a piston 3l. A` stop ring 38 is threaded onto the top end of piston height,` dangerous side sway characteristics, slow ness of operation, and lack of adequate safety 3l for engagement with the top end of sleeve 35 features. to prevent further inward movement of piston It is one of the objects of my'invention to pro 31. The inner end of the piston 31 is recipro vide a hydraulically actuated tripod jack in which cably mounted in cylinder 26, which cylinder the tripods are telescopic and are automatically communicates with bore 33, an extension screw extended in consonance with elevation Yof the 39 being threaded into an internally threaded load, each of the tripods being comprised of a longitudinal bore 31a in piston 31. rI‘he tubular piston member and a cylinder member. member 25 sli'dably ñts in bore 33 of the body, a Another object is to provide a jack capable of guide ring 40 being threadedly mounted in the effecting quick contact with the load to be lifted 20 bore. A stop ring 4l is threaded onto the` top by a minimum of effort, this feature being by end of tube 25 and is adapted to be engaged by way of an improvement upon and a novel adap» the top end of ring lill when the body 30 reaches tation of the invention shown in my prior Patent the upper limit of its movement relative to» the No; 2,154,956. tube, as will be hereinafter described. Ring 4| Another object is to provide a jack utilizing a has a plurality of fluid-passing ports denoted by plurality of liftingV pistons which function to de~ the dotted lines Ma in Fig. 1. crease the pumping effort required to lift a given A piston 45 reciprocates at one end in cylinder load and which provides desirable safety features 32 and at the other end in cylinder 1. The upper against accidental lowering of the load. end of cylinder 32 communicates with the bore Another object of my invention is to provide a 5l of a valve housing 59 through port 52. The hydraulic jack in which hydraulic locks are pro lower or inlet end of the bore 5| communicates vided in the tripods to prevent side sway. with a fluid reservoir 55 in the body by means of Another feature of my invention resides in its tube 56 carrying a screen 5l at its lower end. double acting pressure generating piston. Another port 58 in the body provides communi In the accompanying drawings I show and in cation between valve housing bore 5l and cylin the following description I describe a presently der 33. preferred adaptation of the Ainvention from which A poppet 5B, having oppositely disposed stems it will be obvious to those skilled in the art that my invention possesses still further important 6l», 62, seats by gravity towards the reservoir in advantages and may be carried out in other spe ciñe physical forms, all within the broader scope of the ‘invention as` deñned by the appended claims. In the drawings: b-ore 5I and a ball valve 65 seats towards the A coil spring B3, seating 40 reservoir in bore 5l. against _a plug 5d threadedly mounted in bore 5l, bears against and normally retains ball 65 against its seat. This spring is of a strength to maintain ball 35 seated during initial upward movement of Fig. 1 is a vertical medial section taken on line 45 the body to establish contact with the load to be I-l of Fig. 2; Fig. 2 is a top plan View; Fig. 3 is an enlarged fragmentary sectional view Showing one ofthe valve elements; and Fig. 4 is an 4enlarged fragmentary sectional View showing another of the valve elements. The numeral 5 designates a base presenting a cylinder bore l, fluid passageways 8, 9, 9a, l0 and H, a ñuid reservoir l2, ñuid chambers i4 and I~5-, lifted, but is yieldable to pressure generated by the pressure stroke of piston 45 when further upward movement of the body is resisted by the load being lifted, thus permitting ñuid. to flow into cylinder 33 and provide lifting pressure therein. The valve housing 50 is held in the-:body bore 'l5 by a snap ring 'l5 and packing rings 1l are interposed between the housing and the side wall a threaded socket I1 and a bifurcated boss I8 55. Qf the bore. 2,407,796 3 4 Three bifurcated bosses 88 are provided on the base 5 and between the bifurcations of each of the bosses the lower end of a tube 82 is pivoted by means of pin 83. The interior of each tube 82 provides a piston chamber 85 within which a piston 86 reciprocates. A rod 81 connects each of the pistons 86 to an arm 88 formed integral with the upper end of the body, the upper end of the rod being pivotally connected to the arm seated until a substantial resistance, such as is offered by contact with the load to be lifted, is encountered. During this initial movement of the body, ñuid is drawn from reservoir 55 past poppet | I8 and through port |85 into cylnder 33, any unsafe back pressure on poppet ||8 being relieved by the auxiliary, oppositely seating pop pet ||1. When the load is contacted, its resist ance to further movement of the body 38 causes by pin 89. Thus the tubes 82, pistons 86 and 10 valve 65 to be unseated against its spring by the pressure generated on the upstroke of piston 45 rods 81 provide tripods for the body. A plug 88 and the liuid is therefore forced into cylinder 33 threaded into the top end of each tube l82 pro through port 5B to lift the body relative to the vides a bearing for reciprocation of the rod 81. . base. During this operation, each upward `stroke The lower end of each cylinder chamber 85 communicates with base chamber I5 through a 15 of piston 45 in cylinder 1 draws fluid from res ervoir I 2 through ports 9, 9a, into cylinder 1, flexible tube 95, the three tubes being connect and on each downward stroke of piston 45 in said ed into the port || by means of three connection cylinder lthe fluid thus previously drawn from the members 85. Chamber I5 communicates with reservoir is forced past valve'91 into the lower the cylinder bore 1 through passageway 8, the passage of ñuid from chamber yI5 to cylinder 1 20 ends of the respective cylinder chambers 85 to exert lifting pressure against the respective pis being prevented by ball check valve 91 seating tons 86. The extension screw 39 may be man towards cylinder 1. Chamber I5 also communi ually rotated, as by inserting a rotating pin in cates with reservoir I2 through port I8, the lat hole 39a, to unscrew it from the threaded bore ter communication being controlled by valve member 98 threadedly mounted in the base. To 25 31a. Inasmuch as upon each downward move ment of pistons 88 in chambers 85 fluid is drawn enable fluid to be drawn from reservoir l2 into from the reservoir I2 through tube |88, there is cylinder 1 upon the upstroke of piston 45, pas always some fluid in the upper ends of the sageways 9, 9a are provided in the body in com chambers 85 and by closing valve I8I this fluid munication with chamber |4, the return move may be trapped in the chambers and, together ment of ñuid to the reservoir being prevented with the fluid pressure against the bottom of by a ball valve 9.9 seating towards the reservoir. The upper end 85a of the chamber 85 in each tube 82, above the piston 86 therein, communi cates With the reservoir I2 through a flexible tube pistons 86, side sway of the jack is prevented.~ ' The operation of piston 45 in the respective cyl inder-s 32, 1 being alternate, when the body is being lifted by pressure in cylinders 32 or 33, ñuid will be drawn into cylinder 1 from reservoir I2 and when the body is being lifted by operation of piston 45 in cylinder 1, fluid will be drawn into cylinders 32 and 33 from reservoir 55. |88, a three-way valve | 8| being interposed be tween the ,tubes |88 and |82. The valve |8| is of conventional construction and a hand wheel |83 is provided for manually opening and clos ing thevalve so that it may be closed to trap hy It is possible to provide a hydraulic lock in cyl draulic fluid in the chambers 85 above the pis 40 inder 85 even before the load is fully elevated, tons therein, for the purpose to be hereinafter and to facilitate this I provide an auxiliary inlet set forth. . passageway |35 from passage 8 to reservoir I2, Cylinder 33 also communicates with reservoir passage of fluid from the reservoir to cylinder 1 55 through a portJ |85 and valve member |86, through this passageway being prevented by which latter consists of a valve housing |81 held check valve |36 seating towards cylinder 1,. Thus in a body bore |88 by a snap ring |89. A poppet if it be desired to lock pistons 86 against move I I8 is slidably mounted in the bore of thehous ment during the lifting operation-as may some ing |81, seating towards the reservoir and being times be necessary when a load exposedto heavyv urged against its seat by spring |||. A safety valve is incorporated in the poppet and consists 50 wind pressure is being lifted and such lock is necessary to prevent side sway-valves |8| and of a plug ||5 having a port v| I6 against whose 98 are closed. Thereafter the pressure stroke of periphery an auxiliary hollow poppet I |1 is urged piston 45 in cylinder 32 will lift the load by pro by a spring IIB, fluid passing through ports ||9 jecting piston 31 from the body 38, as is the case provided through poppet ||1. Housing |81 has a tubular extension |28 disposed in the reservoir, 55 when body 38 reaches the upper limit of its travel, and the pressure stroke of piston 45 in the lower end of the tube |28 being closed and cylinder 1 merely returns fluid to reservoir- I2 the side wall being perforated as shown at |2|. ' through passageway |35, When piston 45 is Operation of the device is as follows: To in being operated in cylinder 1 to raise pistons 88, itially contact the top end of the screw extension the check valve |36 is held closed by the screw` 39 or sleeve 35 with the work to‘be lifted, lever plug |31. Also, if it be desired to raise the load 28 is operated to reciprocate piston 45 in ‘cylin by lifting body 38 or piston 31 alone and without ders 32 and 1, respectively, the upper end of providing a hydraulic lock in cylinders 85, this the piston operating in cylinder 32 and the lower can be accomplished by unscrewing plug |31 to end operating in cylinder 1. Upon each down Y > . ward stroke of piston 45 niiuid is drawn from res 55 permit valve |36 to be raised. In lifting extremely heavy loads it may some ervoir 55 past poppet 88 and through port 52 times require too much manual pumping pres into the upper end of Acylinder 32, and on each sure to lift body 30 or piston 31 by pressure gen llPWard stroke of the piston in cylinder 32, prior erated in cylinder 32, and in such cases it is de to establishing contact with the Iwork to be lift ed, the spring-pressedvalve 65 and poppet 88 70 sirable to utilize only the pressure generated in cylinder 1 to raise the three pistons 86. To ac trap the fluid in cylinder 32, causing the body to complish this it is only necessary to screw valve be lifted into contact with the work by virtue of |38 inwardly to open valves 88, 65 which renders the iluid pressure between the top efnd of piston 45 and the adjacent end of cylinder 32. Valve cylinder 33 ineffective. spring 63 is made strong enough to 11016, Valve 6_5 To lower the load, valve IUI is opened and the' 5 6 valve screw 98 `is unscrewed to permit the iiuid Aand each piston chamber above the piston there Y trapped below the pistons inthe respective cyl in, valve means operable to open `and close said inders «8'5 -to flow back into `the reservoir l2 and thus relieve the pressure in «those cylinders. Either simultaneously or subsequently, the valve line, and hydraulic means for moving the body relative :to the base, actuating screw 139 is screwed into ‘the valve rmovable relative yto the base, cooperating piston and piston <chamber means provided in the base and body, a telescopic tripod supporting the body from the basaeach leg of the tripod comprising housing '5D Vuntil its "tapered inner end contacts stem 6l and lifts >poppet El! off its seat, which `force relieves the pressure in cylinder 32 and further operation vof the Ascrew L30 causes stem 62, lwhich is normally spaced from ball `|55, to contact and lift said ball off its seat to relieve .the pressure Vin cylinder 33. Either one of the screws 98 or läß may be employed to control the rate 'of descent by `control-ling the rate of return ¿flow-of the hydraulic iiuid to the reservoir. -|-I‘he advantages of my ¿ack nwill be readily understood when it is realized that such devices are employed to lift loads to substantial heights, 4. the combination of a base, 'a body a tubular member providing a cylinder and a piston member reciprocably mounted therein, vone oi said members being _pivotally connected to 'the base and the other being pivotally con nected (to the zbody, `said body `and base present ing .respectively 'oppositely opening concentric cylinder bores, ,a >pumping -piston reciprocably mounted at one in 'one of the cylinder bores and at its other V‘end in the other cylinder bore, means providing communication between one of often of the order of eight feet or more, and 20 said cylinder bores and said piston chamber and when the load surface is exposed to the wind a means `providing communication between the considerable side sway would develop but for >my ,other Acylinder bore and the cylinder in each of novel construction wherein the tripod pistons 86 may be locked against reciprocation in the tubes 82, Moreover, the multiple cylinders in the pis tonsV materially reduce the manual eiïort re quired to lift a given load and also distribute the stresses. The double acting piston 45 also saves `considerable time. The automatic quick contact the respective legs, whereby reciprocation of said pumping >piston valternately generates pressure in the piston chamber and in the cylinders in the legs, respectively, 5. In a jack, the combination of a base, a body movable relative to the base, cooperating piston and piston chamber means provided by the base ~feature of my device is »also a great advantage as 30 and body, a telescopic tripod supporting the body a time and labor saver. I claim: l.. In a jack, the combination of a base, a telescopic work-engaging member mounted for telescopic movement perpendicular to the base, pressure-actuating ymeans for extending the work-engaging member, and means for laterally supporting the work-engaging member compris -i-ng la plurality oi vtelescopic support members, each including a cylinder and a'piston, `disposed symmetrically »around and inclining towards the work-engaging member, each -oi said telescopic support members being secured at its opposite ends to thebase and work-engaging member, and hydraulic pressure-generating means vcommuni cating with the cylinders of the support mem bers. from the base. >each leg ofthe tripod comprising a tubular member providing a cylinder .and a piston member reciprocably mounted therein, one of said members being pivotally connected to the base and the other being pivotally con nected to the body, said body and base present ing ‘respectively oppositely opening concentric cylinder bores, a pumping piston reciprocably mounted at one end in one of the cylinder bores and at its other end in the other cylinder bore, means providing communication between one of movable relative to the base, a telescopic tripod said cylinder bores and said piston chamber and means providing communication between the other cylinder bore and the cylinder in each of the respective legs, whereby reciprocation of said pumping pïiston alternately generates pressure in the piston chamber and in the `cylinders in the legs, respectively, and means for providing iluid pressure inthe cylinders of the respective tubu supporting the body from the base, each leg of ‘ lar members in a manner to oppose movement of 2, In a jack, the combination of a base, a body the tripod >comprising a tubular member provid the pistons therein by virtue «of pressure generl ing a piston chamber therein and a piston mem ated by the pumping piston, ber reciprocably mounted in `the chamber, one '61, In la jack, the combination of a base pre of said 'members being secured Vto the base and senting >an upright tubular guide member, a body the other lmember ‘being secured to >the body, 55 presenting a cylinder `slidably receiving the guide hydraulic means cooperating with the chamber member, a work-lifting piston slidably mounted of `each leg at opposite sides of the piston therein in the body and reciprocably disposed Vin the whereby to provide fluid pressure on opposite tubular guide member, a cylinder bore in the sides of the piston, and fluid pressure generating body substantially parallel to the said cylinder, a means independent of said hydraulic means co rluid reservoir in the body, a fluid passageway in operating With the body and vbase ’to raise the the Abody providing ~communication between the body relative to the base. reservoir and cylinder bore, a “check valve the 3. In a jack, the combination of a base, a body passageway seating towards the reservoir, a movable relative to the base, a telescopic tripod pumping piston reciprocably mounted in the supporting the body from the base, each leg oi cylinder bore` a second iiuid passageway in the the tripod comprising a tubular member pro body providing communication between the cyl viding a piston chamber therein and a piston inder bore and the first-mentioned cylinder, a mem-ber reciprocably mounted in the chamber, check valve in the second fluid passagewayl seat one of said members being secured to the base ing towards the sai-rl cylinder bore, spring means and the other member being secured to the body, normally maintaining the last-named ,check a fluid reservoir, a iluid pump communicating valve seated and beingof a strength suiîicient to with the reservoir and with each piston chamber oppose pressure generated bv the pumping p-iston below the piston therein whereby to generate when the work-lifting piston is out of contact fluid pressure acting against the piston, a line with the work to be lifted` but yieldable to said providing communication between the reservoir pressure `when the work-lifting piston `is bur 2,407,796 , 7 8 _ dened with the load to be lifted, and a telescopic tripod pivotally secured at one end to the body and pivetally secured at its other end to the base. 7. In a jack, the combination of a base pre senting a fluid reservoir, a first cylinder bore and a second cylinder bore, a body movable relative to the base and presenting a chamber concentric with the ñrst cylinder bore in the base and a secured at one end to the baseï and at its other end to the work-lifting element, said work-lift ing element presenting a pair of parallel cylin ders, a pumping piston reciprocably mounted in the ñrst of the cylinders, a work-engaging piston protractable from and reciprocably mounted in the second cylinder, a ñuid reservoir, fluid pas sageways establishing communication between the reservoir and the ñrst cylinder and between n ñuid reservoir, a work-lifting piston slidably car ried by the body and reciprocably disposed in the 10 the iirst and second cylinders, and valve means in the passageway between the first and second second cylinder bore in the base, a pumping pis cylinders maintaining said passageway closed ton reciprocably mounted at one end in said iirst when movement of the work-lifting element is cylinder bore in the base and at its other end in not opposed by work being lifted, said pumping said chamber in the body, a tripod having legs each consisting of a tubular member providing 15 piston being operable' when moved in one direc tion, in conjunction with the last-named valve a piston chamber and pivotally secured to the means and fluid from the reservoir, to extend the base and a piston reciprocably mounted therein tripod and move the work-lifting` element into and secured to the body, intercommunicating engagement with the work independently -of passageways in the base providing communica pressure inthe second cylinder, and hydraulic tion between the reservoir, the .piston chambers means operable to exert extending pressure on in the tripod legs and the first cylinder bore, a the tripod in response to movement of the pump check valve in one of Vsaid passageways prevent ing piston in the other direction. ing passage of fluid from the piston chambers in l0. In a jack, theV combination of a base, a the tripod legs to the ñrst cylinder bore but per mitting passage of fluid from the ñrst cylinder 25 body, an extensible tripod supporting the body from the base, each leg of the tripod comprising bore to the said piston chambers, a second check a tubular member providing a piston chamber therein and a piston member reciprocably mounted in the chamber, one of said members der bore but preventing passage of iluid from the first cylinderbore to the reservoir, a manually 30 being secured to the base and the other being valve in one of the passageways permitting pas sage of fluid from the reservoir to the ñrst cylin ' ‘operable valve controlling passage‘of fluid from secured to the body, a piston member carried by said piston chambers to the reservoir, a ñuid and projectible from the body, fluid pressure gen erating means for moving the piston members, and valve means for selectively communicating the fluid pressure to the .said tripod piston mem bers or to the said bodyy pistonmember. passageway in the Ybody providing communica tion between the body reservoir and the body chamber, a check valve in said last-named pas-` sageway seating towards the body reservoir, a 1l. In a jack, the combinationV of a base, a second iluid passageway in the body providing body, an extensible tripod supporting the body communication between the body chamber and from the base, each leg of the tripod comprising the second cylinder bore in the base, a check valve in the last-named passageway seating to 40 a tubular member providing a piston chamber therein and a piston member reciprocably wards the body chamber, a spring urging the mounted in the chamber, one of said members .last-named check valve seated, said spring be being secured to the base and the other being ing yieldable to pressure generated by the pump.. secured to the body, a piston member carried by ing piston only when the `work-lifting piston is burdened by a load being lifted, and manually 45 and projectible from the body, hydraulic means so operatively associated with the body andthe actuated means for unseating the last-named piston member carried thereby as initially to two check valves. ' move the body relative to the base until the body l 8. In a jack, the combination of a base, a contacts a load to be lifted and subsequently to work-lifting element movable towards and away from the base, a longitudinally extensible tripod 50 move said piston member relative to the body to lift the load, and hydraulic ’means operable to secured at one end to the base and at its other extend the tripod. ` end to the work-lifting element, said work-lift 12. In a jack, the combination of a base, a ing element presenting a pair of substantially body, an extensible tripod supporting the body parallel cylinders, a pumping piston reciproca bly mounted in the first of the cylinders, a work 55 from the base, each leg of the tripod comprising a tubular member providing a piston chamber engaging piston protractable from and recipro therein and a piston member reciprocably cably mounted in the second cylinder, a ñuid ~ reservoir, fluid passageways establishing commu mounted in the chamber, one of said'members being secured to the base and the other being inder and between the first and second cylinders, 60 secured to the body, a'piston member carried by and projectible from the body, hydraulic means and valve means in the passageway between the so operatively associated with the body and the ñrst and second cylinders maintaining said‘pas nication between the reservoir and the first Cyl piston member'carried thereby as initially to move the body relative to the base until the lifting element is not opposed by work beingV lifted, said pumping piston being operable when 65 body contacts a load to be lifted and subsequently to move said piston relative to the body to lift moved in one direction, in conjunction with the the load, and hydraulic means operatively asso last-named valve means and fluid from the res ciated with the tripod, said last-named means ervoir, to extend the tripod and move the work being operable to lock the tripod pistons against lifting element into engagement with the work independently of pressure in the second cylinder, 70 movement relative to the tripod piston chambers whereby to prevent side sway of the body. and hydraulic means for locking the tripod in sageway closed when movement of the work such extended position. ' 9. In a jack, the combination of a base, a work-lifting element movable towards and away from the base, a longitudinally extensibley tripod 13. In a jack, the combination of a base, a telescopic work-engaging member mounted for telescopic movement perpendicular to the base, pressure-actuating means for extending the 2,407,796 10 work-engaging member, and means for laterally supporting the Work-engaging member compris ing a plurality of telescopic support members, spective cylinders of the support members to each including a cylinder and a piston, disposed provide fluid pressure on opposite sides of the ends to the base and Work-engaginrmember, and hydraulic means cooperating with the re symmetrically around and inclining towards the 5 pistons therein. Work-engaging member, each of said telescopic support members being secured at its opposite HERBERT E. PAGE.