US2672990A - Hydraulic jack - Google Patents

Description

March 23, 1954 3, sum); 2,672,990

HYDRAULIC JACK Filed March 195G 7'Sheets-Sheet l March 23, 1954 7 Sheets-Sheet'Z Filed Mrch 8, 1950 March 23, 1954 E. o. SUNDIN I HYDRAULIC JACK 7 Sheets-Sheet 3 Filed March 8, 1950 In /e//7 7 a March 23. 1954 Filed March 8, 1950 E. O. SUNDI HYDRAULIC JACK 1' Sheets-Sheet 1 March 23, 1954 E. o. SUNDIN 2,672,990

' HYDRAULIC JACK Filed March 8, 1950 7 Sheets-Sheet 5 Milli I ll Mar h 3, 1954 E. o. SUNDIN HYDRAULIC JACK 7 Sheets-Sheet 6 Filed March 8, 1950 45 7/47!!! A a VII/4:.

March 23, 1954 E. o. SUNDIN HYDRAULIC JACK Filed March 8, 1950 7 Sheets-Sheet '7 Patented Mar. 23, I954 if-This invention relates to .a hydraiilicviiack es- .pecially. adapted to be mounted .on.self.=proplled trucksuori other .Ivehicles cor on vessels.

.' .L-The invention provides. a lrelativelyicheapand extremely practical loadi'ngnapparatus first .of tall .Ior .self prope'lled trucks. :The lever beam .can

.beswung at rightiangles to the body of the truck and thelloadcanbe. nulledup to thetruckfrom a point. .at a considerable :distance vtherefrom and then be lifted onto lthegbodyi .The .controldevice permitsutiltingiand swinging of-the lever beam in di'fierent ,planes in iawconvenientemanner. The hydraulic jack. mayrbemraised. to a vsubstan- .-tial.,e1eva.ted heightldespite. the fact that .when ,the lever beam .is its .lowermostspositionthe jjackt does- .not extend, oreextends but ..a.=sh,or.t distance, abovethe .ldriverfsncabin.iofnthe truck. Accordinglto .anuembeodiment of. the invention. the hydraulic Jaclg also 7 includes a pressure. reducing valve which ensures. that the speed lof lowering the load .does not exceed.,a :certainedetermined limit.

.7 More specifically, the invention com'prisesarhw draulic jack to, be. mounted on ayehicleshavingia hydraulic pump, fanlelevating ,cylinder...-f.or .the vertical placement. oi.the, jack, .a piston moving in the cylinder, 2. tpumpesupplyingcthe-hydraulic fluid.v for the jack, ;a .leveribeam at .the top .of .the piston .having two arms of difierentnlength, :a pulley and cable-at the .lcngerarm .oftthe lever beam anda plurality of ,pulleystind .cableslatxthe shorter .arm, several swinging cylinders and. .pis tons connected with 'theipumptoswingrthelower pulleys and their support without: the elevating cylinder and "a control; hydraulic devicelmounted for pivotal adjustment in the two vertical planes which are at right angles to eachotherfor the control of the jack'in these positions.

Other and further objects otthe presentinventioni'will appear fromthe more'ide'tailed de' scription 'setj'forth below, "it being understood that such detailed description is given by .wayflo-f illustration and 'explanati on'only and not "byiway of limitation, 's'ince, various changes. therein may bezmade .by :those skilled in the artwjthput departing from the scope and spirit o;f fthe present invention.

The invention willbe described more in detail in the following, reference being had to .the accompanyingdrawings in which: Fig. '1 is'aside'vievv o'f-a hydraulic Jackiaccoming to the invention, grthe .lever beamibeingin its Iowermost position, I

:E ?ig:=2 Simwsa-similarviewcrimson-ensuin jack with the lever-beam in-tilted position,

-4-Glaims. (01.21235) i "Fig. '3. is ja front.view o'f'the top. endlofithefjack with the lever beam in its lowermost position,

vFig.4 is ,a plan view of the jaclgg'theilever fbeam Jbeing omitted "for. the sake of tclarity,

lEiggfiuis a verticalilongitudinal sectionthrough the main parts of the control [device ot'thejjack, Fig. 6 is a longitudinal sectiontthroughithe control valve included "inithe control devicean'd adjusted for tilting'thedever beam, Fig. 7 is a cross sectioniOIIJinejFVIIQYII'Df ranged ;at the, rightjend, ,(as viewed .iinlFig. 6) ref .the control valve, .said ;valve .oceupying.;the.;,position shown in'lFig; 8,

r Fig. 1"0v shows alilongitudinal section similarlto Fig. 6, the control valvernccllpyin howeverithe position for swinging the'ilever' beamjin one direction in a "horizontalplane;

Fig. '11 risias cross section onflind'XIQXI, of

;Fig. 12 a cross sectionionilineixllimiof 'a; vehicle with anydraulic ,j ack according to they present invention, and

Fig. 14 is a schematicdiagram'. of jtheefluid system. Theelevating cylinderfil of the hydraulic jack projects: vertically "from'ga base plate 2 which is mounted on thezchassiyframe-3 of a selfpropelled ztruck-"behind-ithe driverfscabin 4 .01, the latter." "The: chassis frame and the driverscab'in are shown by 'd'ashand dotflines. ".Vertically. movable in the elevating cylinder 1 ;a,piston1f5,:'the upper end of which is shaped likea forkifi with a transverse axlef] about. which a leverlbeamjfliis mounted'forpivotal movement'in a vertical plane. Said lever 'beam 'has arms of 'Ldifieren't; lengths and its long-arm 'which" comprises "telescopically interengagin'gimovable' tubes :9, ill), siapplied in its 'lowermost-jtposition"against a stop 1| .zatathe topgend OfthBfDiStOIl 5; JIn the lowermost position of.:tl' e piston 5 the lever beam. Bris; retained in the horizontal position by 'thejlowerportion of the stop H beingintroducedibetween two-searwardly' extendingv pins "(2 which .are secured to .a bracket l'3,. which bracketsupportsa number of pulleys 1'4. rotatably mounted .at,,the -outer- -.end thereof.v sali'chbracket 1:3, is rpiMetally miounted at the top-lend of; theselevatingnwlinder .iceiBotatably mounted on theshort arm 15 of the lever .to swing clockwise from .pins are two cylinders 23 'valve 21 included in beam are a corresponding number of pulleys 16. A steel cable or the like I! is passed around said pulleys l4, l6 and has one end thereof secured either to the pulley bracket 13 or to the arm l5. Further, said cable is passed around a pulley i3 rotatably mounted at the outer end of the long lever beam arm. A lifting hook 19 or other lifting means is attached to this end of the cable ll. The cable may also be provided with an abutment 2!) which is adjustable on the cable at various distances from the hook 19. The length of the cable I! is 50 adapted to the length of stroke of the piston and to the number of pulleys l4 and it on the bracket l3 and the lever arm so that when the hook l9 or the abutment 20 abuts against the outer end of the long lever arm or a stop thereon, said piston has not made its full stroke but is able to move a further distance upwardly. At the end of the upward movement of the piston 5, the lever beam 8 is thereby caused the horizontal position shown in Fig. l to the upwardly inclined position according to Fig. 2.

inder l, with vertically upstanding pivot pins 22.

their one ends on said which are adapted to swing the lever beam 8 in a horizontal plane and which will be called swinging cylinders in the following. Pistons 24 are axially movable in the cylinders 23 and are each hingedly connected by means of a pin 25 to the pulley bracket I3.

A hydraulic pump [60 (schematically shown in Fig. 1) which is mounted on the truck is driven by the truck engine and pumps oil from an oil supply through a supply conduit 26 to the control the control device. Said control valve is connected by a conduit 28 to the elevating cylinder l below the piston 5 and fur- Swing ably mounted with .thermore it is connected to the two swinging cy inders 33 by two conduits 29 and 39. An oil filter 3! (Fig. 3) is inserted in the supply conduit "26. A conduit 32 leading from the control valve 21 emerges in the conduit 28 and a check valve 33 is inserted in the conduit 32, permitting the oil to flow from the control valve through conduit 32 into conduit 28 but not in the reverse direction. The conduit 28 is connected by a con duit 34 through a reduction valve 35 to the control valve The latter valve 21 is connected to return conduit 36 and to the inlet of the pump or to the oil container situated there. A safety valve 31 is mounted on the lower side of the con trol valve 21 and is operative when the oil pressure in the supply conduit 26 rises over a predetermined value.

Rotatably and axially movable in the valve housing 33 of the control valve 21 (see Figs. 5 to 12) is a valve body 39 which comprises a sleeve fixed to a control rod 4| axially extendin through the valve housing by means of a p the cylinder wall of which sleeve is considerably thinner in one end portion (the right end portion according to the drawings) than in the other (left) end portion so that there is formed a free annular space 42 between the control rod 4| and said thinner cylinder wall 43. A row of three ports 44 are provided in the cylinder wal1 43 and by rotation of the valve body 39 said ports can be brought to register with three corresponding ports 45 in the valve housing 38. The latter ports are situated at thelower end. of conduit 3 There is a fourth port 46 in the valve body which may be brought to register with the mouth of conduit 39. Furthermore, a row of six ports 4'! are provided in the cylinder wall 43 and at a certain angular position of the valve body 39 these ports connect the space 42 over an opening 48 in the valve housing 38 with a chamber 59 in which the supply conduit 26 emerges. The left (thicker) portion of the valve body 39 is provided with a peripheral groove 59 from which an axial groove 5| extends towards both sides. Said groove is provided in the mantle surface of the valve body. The control rod 4| has an axial groove 52 for re turn oil from the conduit 29 leading from the left swinging cylinder 23 (as viewed in Figs. 3, l) to the space 42. The latter is in communication with the main return conduit 36 through a port 53 in the valve housing 38. The safety valve 31 is inserted in the conduit 54 leading from chamber 49 to the main return conduit 36.

The control rod. M has a radially extending coupling bolt 55 provided with a surrounding,

easily rotatable sleeve. By axially displacing and rotating the control rod said bolt may be moved within a substantially V-shaped opening 56 in the valve housing 38. At its upper portion the opening 56 is formed with three coupling notches 5'1, 58 and 59 and at its lower portion there is a further coupling notch 66. The surfaces 6| extending obliquely upwards from the last-mentioned coupling notch 60 serve the purpose of guiding the bolt 55 and thus the control rod 4| when the control valve is acted upon.

The control rod 4| extends to both sides of the valve housing 38 and is surrounded by tubes 62 fixed with their one ends to the ends of the valve housing 38. The tubes 62 are of such a length as to reach somewhat outside the lateral edges of the truck body. Rotatably mounted on each of the outer ends of said tubes is a sleeve 63 to which a link 64 has its one end hingedly attached, while its other end is hingedly attached to one end of a two-armed control lever 65 which is pivotally mounted about a bolt 66 on the outer end of the sleeve 61. Said sleeve is secured to the respective outer end of the control rod ti by means of a pin (fraction pin) 68. This arrangement permits axial displacement of the control rod and the valve body 39 by means of the control lever 65 and adjustment of the valve body in its various angular positions.

When the control valve is in zero position (Figs. 5, 8 and 9) in which the coupling bolt 55 is situated approximately midway between the coupling notches 58 and 69, oil is pumped from the pump through conduit 26, chamber 49, port 48 in valve housing 38 and ports 41 in valve body 39, through space 42, opening 53 in the valve housing and the return conduit 36 to the oil container. When the control rod 4! and thus the valve body 39 are rotated into such a position that the coupling bolt 55 is introduced into notch 56 (Fig. 6) oil flows under pressure from chamber 49 through the peripheral groove 50 and over the check valve 33 and conduits 32 and 23 into the elevating cylinder I. The port 46 in the valve housing is then closed by the cylinder wall 43 (Figs. 6 and '7). When oil flows into the elevating cylinder l the piston 5 is pressed upwardly, the cable I! running to the right (as viewed in Fig. 2) over the idling pulley 18, whereby a load 69 suspended from the hook 19 is elevated to the necessary height over the body 3. If the load 69 must be lifted especially high, the piston 5 is permitted to move upwards also after the abut- -mentl:orethe1ncek :lfi-l-hasrheen appliedaagainst athe onter end rot; 12138 long lever arm.

.-.Thedeven beam--.8-;is ltheniswung-clockwise about aaxle J Afterathe load-1hasereachedthedesired height.-..( m-.theecase vwhereethie load :is to be unlaadedirom the truck body) mule-0011131111 lever 5.5 .issovswungwthat the bolt 55 isl-rsituated in czenonposition: (Fig; x-9-)w- .when the valve body -39 occupies -.F?ig. deposition. T .Then I the oil flow :into .the elevating :cylinder J ceases land since -1the cylinderrvvall 4.3 this-position :closesethe ports 45 .in the valvahousing land .the -.check.valve 33 lonly pern'1its..flow in an upward directionthrough ,lcondnit 3 2.,..-oil is l-prevented :irom. beingmdriven back out of the lifting cylinder lip-for which r lreason- .the. .load ,69 remains in elevated position. rWhenl-the-coupling-lever E5 isswung in such -a ,adilfifitiOIl in aqplanecoinciding -,with.the control mod-Al, that-thebolt. '55 abuts against the .right .sidelsurface o'fopening 5t and the control-ro'dA-l with thescoupling lever is then rotated until the .bolt 5.5.engages'withthe right-hand .notch 59, 'the .valvesbody 3.9 occupies the position shown in Figs. .10 :and 1.1. The oil is then squeezed-trom chamber 49 .intothe left end of the axial groove '51 and through .theuperipheral groove '50 and the .conduit .3=ll..into .the right-hand swinging cylinder 23 .(Fig.v 4) .The piston z l ofsaid swinging cylin- \deriis thereby ,pressed to the left, which involves that (the .fpulleybracket. 13 is swung counter- ..clockwise. .IIhe runs ofthecable l l situated betweenpulleys 14 to :16 will thereby be inclined, the pull inthese cable runs involving that. the lever beamj is,.a1so swung counter-clockwise ac- .cording .toli ig. 4, whereby :the. load is moved out from the body .of the .car.

'When. thecpiston of the right-hand swinging cylinder. .23 ispressed tothe left; the piston of the left-hand swinging cylinder 23 is urgedinto this cylinder, the oil. situated. thereinbeing pressed through conduit .29 and .over the bypasschannel 52 of the...control..rod 4| into the. space 42. and through the -return conduit 36 back to the oil container. Should the lever beam 8 be swung in the opposite; direction, .-it would be .necessary to move and .toturn thevalvebody3.9.into a position in which the bolt55 engages the left coupling notch-51, the peripheral groove 50 in valve'body 39 registering-vvith the-conduit 29 leading to-=the leftehandxswinging cylinder 23 (Fig. 4) -In=*th'is positionvdf the valve -b0dy" 3-9-1lhe port =is opposite the point where the conduit 30 from the right-hand swinging cylinder 23 emerges into the valve housing 38, so that the oil in this cylinder may be returned to the oil container through the space 42 and the conduit 36. When the control lever 65 is then so swung that the bolt 55 is sliding against either of the guiding surfaces GI of the opening 56 leading to the lower coupling notch 60, the valve body 39 occupies a position in which the inlet from chamber 49 to conduits 29, 30 and 32 is cut off, but the connection between chamber 539 and the return conduit 35 is open through port 48 in the valve housing 38 and the ports 41 in the valve body 39 as well as through the space 42 and the opening 53. The ports 44 in the valve body 39 register with the openings :85 in the valve housing 38. Thus, elevating cylinder I, conduit 28, reduction valve 35, conduit 34, openings 45 and ports 44, space 42, return conduit 36 and oil container are in communication. By the weight of the piston 5, the lever beam 8 and the load 69 the oil is pressed out of the lifting cylinder I back to the oil container and the load is lowered.

6 Mnpeciahstepsraremotrtaken, ameasderziload iflcw'onld helloweredsmorefrapidly ithania gliter wnerforfthereturn iilow of the ioiLl would ofcourse take rt-placezmorerrapidly ';thanat :a i'lighter dead ldueftorthe higher-pressure; :However, the use of the? pressure reducing "valve 25 *results inl' ithe loweringcof rthelloadtakingplace;atzapproximately the samerr-speedreither. -the: load iisheavy or light. x .rnxiallyrmovable fin ibore 3'10 in the valve housing ll of the pressure reducing valve is a conical :valve: body. 1:2. disposed" to-rprovide an. annular space Jllibetweenritself andiasseat l3 'in'the valve "honsingz'when athez'valve is open. Apiston l6 movable the-lb'ore 10 isra'ttached totthewalve sstem flfir r:A;:screw :spring 18 fislcclampedbetween ar-screwonipple ll! .atltonezend of the valve houszingr'llznnd the-piston 1.6,.1thePtnipple Tl enabling iad iustm'ent of zthei'itension of :said "spring. f- :The movements :ofrthe valve :body .12 12,318 limited by a stop-"M11119. When on lowering. the load-the -oi1 :pressure is:suitablerfior normal lowering speed the valvezrbody l2 occupies approximately the .position-shown in Fig. ;5-.:: An increase of the oil pressureresu-lts :in =the:valve body IZ-Jbeing pressed towards :thewseat- 1.3 by the action of spring 18 due to the fact that the valve body has a larger operative end surface than piston 16. The through-flowsectionofspace 'Mis thus decreased. However; since the-speed of the 'flowing liquid increases onaccount-o'fthe pressure increase and substantially=the same amount of liquid; :under pressure will flow through :the .valve' per unit of time beforeaas after said inc-rease. Thismcans that :thespeed at which theload lowered remains approximatelythe same either the load is heavy orllight.

It is thought that the invention and its :advantages will be understoodfromthe foregoing description and it 'is apparent that various changes may be (made inthe form, "construction and arrangement of the .parts without departing trom-thespirit :scope of the invention -or sacrificinglitsmaterial advantages; the formhereinbefore describedrand illustrated in the drawings being .merely a, preferred embodiment thereof.

, :WhatuI-claimais:

1-1. A hydraulicjack adapted to besmounted on vehicles or--vesse1s,: comprising .-in combination a hydraulic-pump mounted on the vehiclean elevatingcylinder'vertically mounted on the-vehicle, a piston, movable. up and down in said cylinder, a conduit connecting said cylinder to said pump to force pressure liquid to the lower part of the cylinder, a lever beam supported on the top end of said piston and having two arms of different lengths, a pulley at the outer end of the longer of said arms, a cable over said pulley, a lifting implement at the outer end of said cable, a bracket and a plurality of pulleys on the outer end of the shorter arm for the same cable, a plurality of similar pulleys corresponding to the number of pulleys of the shorter arm, a pulley bracket mounting said pulleys supported by the elevating cylinder and mounted for swinging movement in a horizontal plane, said cable being passed around said pulleys, said cable being attached at its free end to one of said two pulley brackets, two swinging cylinders connected with the pump, pistons movable in said cylinders for swinging the lower pulley bracket about the elevating cylinder in one or the other direction, a control device inserted in said conduit between said pump and the elevating and the swinging cylinders, a control valve in said device adapted to lead liquid under pressure optionally to the elevating cylinder orto any one of the swinging cylinders by adjustment into different positions, a valve body for said control valve and a valve housing therefor, said valve body being rotatable and axially displaceable in said valve housing, a control lever, a control rod connecting said control lever to said valve body, said control lever being mounted for pivotal adjustment in two vertical planes which are at right angles to each other.

2. A hydraulic jack as claimed in claim 1, said lever beam being pivotally mounted on the upper end of said piston, a stop member on the outer end of said cable, a stop on the long arm of said lever beam, the length of the cable passed around the pulleys of the pulley brackets and the pulley mounted on the long arm of the lever beam being adapted to the length of stroke of the piston and to the number of pulleys on the short arm of the lever beam and on the lower pulley bracket whereby when said stop member on the outer end of the cable abuts against said stop on the long lever beam arm, said piston has not performed its full stroke but can move a further distance upwards in order to tilt the long arm of the lever beam upwardly.

3. A hydraulic jack as claimed in claim 2, a substantially V-shaped opening rovided in the cylindrical wall of said valve housing, the upper edge portion of said opening having three coupling notches of substantially the same size also provided in the wall, a coupling bolt and an easily rotatable sleeve therearound mounted on said control rod, said notches being arranged for said coupling bolt and said surrounding sleeve, said valve body and said casing having openings and channels therein, the valve body being so arranged that by means of said openings and channels in said body, cooperating with corresponding said openings and channels in the valve housing, said valve body can lead liquid under pressure to the elevating cylinder when the valve body has been turned through a distance in one direction and the coupling bolt inserted in the middle one of the three coupling notches but cutting off the pressure liquid from the elevating cylinder when the valve body has been turned through a dis tance in the opposite direction and the coupling bolt occupies a position midway between the intermediary notchand the coupling notch arranged at the bottom of the V-shaped opening,

and the pressure liquid being discharged from the lifting cylinder when the valve body has been turned through a distance and the bolt engages with the lower coupling notch and the valve body leading the liquid under pressure to either of the swinging cylinders for swinging the lever beam in a horizontal plane when the bolt, after the control rod has been axially displaced in either direction, engages with either of the two outermost notches, but the pressure liquid being cut off from these piston cylinders when the control rod and the valve body have been turned through a distance whereby the bolt occupies a position midway between one of these outermost notches and the lower coupling notch.

4. A hydraulic jack according to claim 3, the valve body comprising a cylindrical metal sleeve passed onto the control rod and fixedly connected thereto by means extending through diametrical holes in the valve body and the rod, the cylinder wall of said metal sleeve being considerably thinner in one end portion than in the other one so that a free annular space is formed between the control rod the thinner cylinder wall, and the other end portion of the valve body having a thicker cylinder wall, being provided with an outer peripheral groove situated approximately at the middle of the valve body, which groove is so arranged that when the valve body is displaced and rotated it can open or break the connections between the channels of the valve housing and the valve body for permitting the liquid under pressure to flow into the elevating cylinder and into the swinging cylinders, respectively, and the thinner cylinder wall of the valve body having ports cooperating with corresponding ports in the valve housing and so arranged that the pressure liquid from the elevating cylinder and the swinging cylinders can be cut off and discharged, respectively, from the discharge conduit of the valve in accordance with the angular or axial position of the valve body in relation to the valve housing.

ERIC OLOV SUNDIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,392,004 Sherman Jan. 1, 1946 2,445,160 Torgersen July 13, 1948 2,462,926 Wilson et al. Mar. 1, 1949

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