US1401761A

US1401761A - Lifting-jack

Info

Publication number: US1401761A
Application number: US454235A
Authority: US
Inventors: Elmer A Clark
Original assignee: W E PRATT
Current assignee: W E PRATT
Priority date: 1921-03-21
Filing date: 1921-03-21
Publication date: 1921-12-27
Anticipated expiration: 1938-12-27

Description

E. A. CLARK.'

LIFTING JACK.

APPLICATION FILED MAR. 21| 192|. v Patented Dec. 27, 1921.

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ELI/IER A. CLARK, or zroLIET, ILLINoIs, AAssreivon To W. E. PRATT, or CHICAGO,

' 1 ILLINOIS. y

' LIFTING-J'ACK.

lat least of which iis carried by -a pivoted lever so that by `oscillating' the lever in a vertical plane the liftingbaris raised step by step. Provision has been niadefin jacks -of this Vcharacter .for reversing. the action yof :the pawls so that when desired zthe oscillation ofthe 'lever lowers :the lifting vbar step by step. It is the-.object 'of .my

invention to Aprovide a simpleconstruction of jack having this reversible feature in which the reversing means is readily accessible when the Vjack is in operation. In one rform of my invention the reversing mechanism may be operatedieither by the fingers Vor any convenient stick or `tool by'which the .reversing mechanism may rbe reached without the operator being obliged toffget in under the vehicle to which the jack is applied. In anotherform of the device the action .of the pawls is reversed ,by means of a rod extending` ythroughor along-the handle within reachl of the operator without shifting from the Vposition which he, occupies when oscillating the lever handle.f The preferred form of the invention is shown Y in the accompanyingdrawings andset forth in the following' description. It is-to be understood, however, that Vthe specific dis- .the :standard and .at its upper lfend' is'slid- I -ingly connectedto the link 22:- Thissliding v closure is :for .the purpose ofexemplilication only and that lthe scope ofthe linvention is defined in the following claimsin which-IV Vhave endeavored `to distinguish `it from" the f prior art so far as known to mewthout,

however, relinquishing or ahandoningany portion or rfeaturethereof;l 1

In the accompanying-drawing `Figure l is a sidefelevation partly in section offthe. preferred form of my invention, Yasadapted.

. for reversing bymeans,insideofzthelhandlm i the cover plate ofthe standard being -'re-.

' moved; Fig. 2 is a vertical elevation partly in section. at right angles to that of Fig.'

Specification of Letters Patent. v:[aijen'ted 'Dee Application le'March 21, 1921. Seria1No.i454,2l35. i

er, 192i.

1 showing, however, the cover plate in place; y

Fig. 3 a :horizontal section on theline 3-3 fof Fig. '11 with the `cover'plate in place VA however;rl4"ig. 4.a vertical'section in a'plane '1n ...the line 4 4 of Fig. l and..F1g. 5 .a side elevation partly in section vof so much `of that form of the invention in which the handler-is provided with; reversing `means f as is necessary to an `understanding of the construction.

In `the several views each partis identified by the fsarme 'reference' character :wherever it occurs. i a In the form of the inventionfshownfin drawings, the standardl 5' .is preferably :i

casting with ka suitable' base 6 having a fg'roov'e 7 :for the reception ofthe lifting 'bar 8 iand a chamber -or i-recess 19 for fthe -pawl mechanism. Acover lp'late lO isse- `cured to thestandard after the lother .parts have been `assembled by'serews 11.

Alever lQispivoted on a fulcrum V13 `ex- -tending between Y.the sidekv :wall 14 -of -the pawl chamber andthe'cover :plate lOrandis `Capable cfa limited` oscillation in afvertical plane The lever comprises la socket l5 to receive va Ahandle for oscillating the-lever anda generally triangular vhead 16 to which y,pawls 17, :1-,8 are -pivotedat the upper andk flower angles thereof respectively., The` upperpawlis guided-.into the raolcby the curved portion 19 of the housing andthe lower pawl by ythe curvedv :portion 2O of `a lug 2l n which may Pbe .-.cast :integral with'. vthe standard.- Tliefpawls 17, 18 are connected :together 4by Ylink 22, which' is pivoted at 23 to the lower vpawl and has a pin'and v slot connection ,24 with the upper pawl so as to permit a bodily `movement'relative'l tothe latter. A YHat spring'Q is secured at Vone end to 'a ,transverse l.member .'26 0n connection' is preferably formed by bending the ,upper end of thespring inward as atl 27 and perforating the inwardly bent end to Vreceive a yverticalV Ffmger 28' which is @am BO--whichis pivotally mounted-uponthe lever atl. The camfhas a' nose'fQ-.wliich engages the bulge lor Vcurved portionof thek spring and a pairfof arms 33, -34 extending respectively through a slotin the upper ing movement of the lifting bar. ln this position the nose of the cam bears against the spring and the latter exerts pressure on 'the link 22 tending'to throw the pawls 17,

lWhenY 18 into engagement with the rack. the handle is operated on the downward movement of the latter the lower pawl engages a tooth of the rack and raises the barv and the upper pawl slips over a tooth. When the handle is raised the upper pawl maintains the rack in position and the lower .pawl slips over a tooth to the one below and so on.

When the position of the cam is reversed so that it exerts no pressure on the spring, the resilience of the latter acting from its point of attachment to the standard tends to force the link and consequently the pawls outward. VVith'the parts in this position, that is to say, with the spring exerting a tension upon the pawls tending to withdraw them from the rack, when the handle is'at the lower end of the stroke the liftingl bar is supported on the lower pawl. -As the handle rises the rack descends with the lower pawl until it is engaged by the inward movement of the upper pawl due to the engagement of the latter with the curved surface 19. This releases the lower-pawl which is withdrawn by the tension of the spring from the rack and on the downward stroke of the handle it passes the tooth with which it has been in engagement and at the end of the downward movement of the handle it engages the tooth next above and so on. rlhus a very simple reversible construction is provided. The arms of the cam project beyond the upper and lower walls of thehandle socket respectively and in order to shift the cam it is only necessary to press against the proper arm and this may be done either by a finger or by a convenient.V

rod or tool.

As heretofore stated itis convenient when the jack is in operation and is supporting the axle of the vehicle or the like to be able to shift the mechanism to the lowering position without moving fromthe end of the operating handle. ln the form of the device shown in F ig. 5 l have provided for this method of manipulation. rlhe lower section f 37 of the handle, whichniay be formed with an exension if desired, is' hollow, the endsl thereof being blocked at 38, 39, the blocks being'perforated at 40, 41 to form guides for the cam operating push rod 42 which extends longitudinally ofthe handle. Preferably the hollow handle section is provided at its lower end with some means for interlocking it with the socket 15. For this pui1` pose have shown the socket 'as formed ymay be shifted longitudinally in anyV delhowever, an extension 5l may beV provided the holding pin may be forced inwardly to free it from the perforation 43 in the socket. The push rod 42 is so located in the handle that when it is pushed inwardly or toward the jack it engages the lower arm or horn 34 of the cam lever and shifts it from the position shown in Fig. l to the position for lowering the lifting bar. The push rod 42 8O sired manner and l have shown for this purpose a collar 43 upon the upper end of the hollow section. of the handle which collar is free to turn to a limited extent on the handle. rlhe upper end of the push rod is bent laterally at 49 and enters'a cam slot 50 in the collar so that by turningsaid collar vin one direction the push rod may be forced downwardlyor toward the jack and by turning it in the other direction it may be drawn upwardly.

The hollow handle may be of such length that the rotary collar may conveniently be located at the end thereof. lf it is desired,

and in that case it is preferably detachably locked to the collar byk spring pressed holding pin 52 operated by a thumb pin 53 which may be similar in all respects to the connection between the hollow handle section and the lever socket. Obviously if desired the handley just described may at any time be replaced by a simple bar and the reversing cam operated in the manner first described. A

l claim:

l. ln a lifting jack, a standard, a lifting bar vertically guided in the standard and having a rack,- a lever pivoted to the standard for movement in a vertical plane, a pair of pawls engaging the rack, one at least of which is pivoted on the lever, a link connecting the pawls, a spring secured at one end to the Standard and engaging the link at the other and normally exerting a pressure on the link to withdraw the pawls from the rack and means mounted on the lever for engaging the spring to reverse its action on the pawls. l I

' 2. ln a lifting jack, a standard, a lifting 120 rbar vertically guided inthe standard and having a rack, a lever pivoted to the standard for movement in a vertical plane, a pair of pawls engaging the rack,- one at least of which is pivoted on the lever, a ylink connecting the pawls, a spring secured at one endfto the standard and engaging the link at the other and normally exerting a pressure on the link to withdraw the pawls from the rack and a cam pivoted on thelever and engaging the spring to reverse its action on the paWls.

3. In a lifting jack, a standard, a lifting bar vertically guided in the standard and having a rack, a lever pivoted to the standard for movement in a vertical plane, a pair of pavvls engaging the rack, one at least of Which is pivoted on the lever, a link con-, necting the pavvls, a spring secured at one end to the standard and engaging the link necting the paWls, a spring secured at one end to the standard and engaging the link at the other and normally exerting a pres.V

sure on the link to Withdraw the pawls from the rack, a cam lever' pivoted on said lever and having a nose engaging the spring and oppositely extending arms for operating'the same. Y

5. A lifting jack, a standard, a lifting bar vertically guided in the standard and having a rack, a lever pivoted to the standard for movement in a vertical plane, a pair of pawls engaging the rack, one at least of Which is pivoted on the lever, a link connecting the paWls, a spring secured'gat one end to the standard and engaging the link at the other and normally exerting apressure on the link to Withdraw the paivls from the rack a cam lever pivoted on said lever having a nose engaging the spring and oppositely extending operating arms, a handle socket, the latter being slotted to permit the arms of the cam lever to extend there- G. lifting j ack, a standard, a lifting bar vertically guided in the Standard and having a rack, a lever pivoted to the standard for movement in a vertical plane, a pair of pawls engaging the rack, one at least of which is pivoted on the lever, a link connecting the paWls, a spring secured at one endto the standard and engaging the link at the other and normally exerting a pres- 'i sure on the link to Withdraw theV paWls from the rack, a cam mounted on the lever for engaging the spring to reverse its action on the -pavvls,k a socket on the lever into Which Said cam extends, a hollow handley 1n said socket and means movable longi-V tudinally of the handle for actuating the cam. .e

7. A lifting jack, a standard, a ,lifting bar vertically guided in the standard and having a rack, a'lever pivoted to the standard for movement in a vertical plane, a pair of paWls engaging the rack, one at least of i which is pivoted onthe lever, a link con-- necting the pavvls, a spring secured atA one end to the standard and engaging the link at the other and normally exerting a pressure on .the link to Withdravr7 the pawls from the rack, a cam mounted on the lever for engaging the Spring to reverse its action on the pawvls, a socket on the lever into which said cam extends,.a hollow handle in said socket, a rod movable longitudinally of y the handle and engaging the cam for shifting thesame and means engaging the opV posite end ofthe rod for shifting the latter.

s. A lifting jak, a Standard, a, iiaing bm! vertically guided in the standard and having a rack, a lever pivoted to the standard for movementin a vertical plane, a pair of paWls lengaging the rack, oner atleast of which is pivotedk on the lever, a link connecting the pavvls, a springsecured at one end to the standard and engaging the link at the other and normally exerting a pressure on the link to Withdraw-the pavvlsY from the rack, a caminounted on the lever for engaging thespringto reverse its action on the paWls, a socket on the leverinto which said cam extends, a hollovv handle in said socket, a rod movable longitudinally of the handle, a collar rotatably mounted 'on the handle, a cam Slot in said collar andv a projection on the rod extending into said slot ELMER A. CLARK.