US1926711A - Lifting jack - Google Patents

Description

Se t. 12, 1933. H. w. CLARK 1,926,711

LIFTING JACK Filed Nov. 30, 1928 2 Sheets-Sheet l 1', I ll INVENTOR .3 H u w. M,

Sept. 12, 1933.

H. W. CLARK LIFTING JACK 2 Sheets-Sheet 2 Filed Nov. 50, 1928 INVENTOR Hm w. M

Patented Sept. 12, 1.933

I f 1,926,711 e I nrF'rrNG J CK. v Harold w. Clark; Alliancd' ohio. assignor a 7 "The Buckeye JackManufacturing Company,

AlliancaOhio, a corporation of ohio Application Novmberflli, 1928.." l i S r rzaw V This invention relatesto lifting" jacks, and

particularly 'to lifting jacks of the 1 screw type. t is herein illustratedand described as applied to'a jack for use with automobiles, although it 0 has numerous other. applications.

In automobile work, particularly with the..advent of the balloon. tire, it is necessary that a jack .-Y. n qa'ver 1ow retracted height. and a relatively high [lift be provided; For this reason if) jacks;of;the',.double screw type have come, into favor. f Such jacksgwhile they providethe necessary range ofheight and thelowretracted height,. have been open to numerous objections 'Variou's schemes for insuring that the severalscrews may,

I be extended to the' utmost have been proposed,

butflmost of them are open to the objectionthat' they are complicated. or are expensive to manu facture...

. A'fur h rd isadvantage a jacksof m sa has been that the eleyatingtmechanism is closev tothe top oil the jack, so thateven a light effort appliedto the handle has been sufficient to turn the jack over; Thisdefect is particularly notieeable on rough roadways. Such jacks-have.

also been open to the objection that the screws and bearings have beenf unprotected anldfllikel'y to wearand cut on quickly, because of sand and grit.

I'provide' a jaclr the screw type whichhas I a very low center of gravity, and in whichthe power is applied near the base, which may be manufactured at afvery low cost, seam which all oi thQiDZYtS are-adequatelyprotected. The

isnot in any danger oi-getting out of. order.

In the accompanying drawings illustrating the present preferred. embodiment of l the invention, Figure lis a side elevation of the jack partly broken away, in elevated position;

Fig. 2 .ie -a transverse vertical section through the jack,,the screws. being in retractedlposition; Fig. 3 isatop plan view;

Fig. 4" isahorizontal sectioni-taken on the.

' -line IV--IV .of Fig. 2 and Fig. 5 is a similar view moi Fig-.2. The jack shown in the drawings comprises a standard 2 0i cylindrical form having an integral base 3. The. topfajce ofxthe standard supports'a metalsleeve 6 is welded to thenutas indicated at '2, and .thissleeve extends downwardly over the standard 2, terminating adjacent the base 3, The sleeved is journaledon the standardat. B and 9 so that it isfreely rotatable thereon, but

35 elevating mechanism is simpleand compact and "high speed.

ake r l hl m ball bearing ewhich ,.in{turn,carries a nut 5. A.

e i in. Sea ease ent" .wiriit ie standard, I

A driven bevel fgearlo' is welded to bottom 0f. the sleeve 6 as indicated .at 1-1. This gge'ar meshes withteeth 12 formed oniorieend of; a driving member 13L The. driving member is io'ur-v naled in abarrel 1 11 formedgintegral with the j base 3 The'driving member is provided with 1 a socket 15 for -the reception: of a.. jack.operati11 the b arre1,.fand theprojecting portion on'which the teeth 12 are formed is of thesame diameter.

The socket lfi jis larger than thebody'portion 1.16 sov that*a..shoulder 'bearing'against one end ,of the barrel 14 isiprovidedg. a 4

"By'reas'onj of the fact that the projecting portion carrying the teeth 12 .is at least as small in diameter as the body portion 116, the driving 'rnember 13 may be slid. "into thebarrel. '14. .Q'It is held in place by a split ring .jl6"which'is pressed into a groove formed in the driving member after the driving member. has been put-in place. By reason of. the fact. that the driving mech am'sm is adjacent the base, the centerof gravity of the. jackis materially loweredand the danger v of ltippingthe jack is materially decreased. This is. due not only'to the low center of gravity, but 1 also theffact' thatthe turning moment applied by the handle is eiiective very near to the point j ofsupport. 1 5 The sleeve 6 provides. a very useful effective grip wherebythe nut 5.may be rotated for raising or loweringthe'jacklbyhandto any extentdesjir'ed. .Thismakes it much easier. to, preliminarily adjust the. jack tonear the desired height, and the raising or loweringflcan be effected jby hand v at The nut 5 engages aprimarylifting "screw l'l. I This screw-is movable up or. down. 'within the hollow standardZ and is provided-with diametri- 9 cally spaced lugs 18 adjacent its bottom. During the intermediate portionv of )the' vtravel of 'the screw 1'7, the lugs 18 are engaged by ribs 19 formed on the inside of thestandard','which1ribs posi-. tively prevent rotation of the screw 17, whereby rotationjof the nut5 causes the screw .to' raise or lower. The screw 17 is'hollow and is threaded at its upper end to accommodateja secondary screw '20: having a V loadgengaging "saddle '21.- When the screw :17 reaches the upward limittot its travel, thelugs 18 clear;the topsof the ribs .19; thus leaving the screw llfree' torotate. The

=upward movement of the screw 17 is terminated by the fact that the thread of the screw'is ter-'- no minated a sufficient distance from the bottom handle. it has'a body portion 16Iwhich lies in its so that it'locks in the nut just after the lugs 18 clear the ribs 19. Continued rotation of the nut 5 therefore causes the screw 17 to rotate with it,

and since the saddle 21 is engaged by the load,

thus preventing rotation of the screw 20, the screw is threaded upwardlyfto further raise theload.

When the load is to be loweredfit is, desirable that the secondary screw 20 be actuated first. It

sometimes happens that the friction of the small? screw in its nut is greater than the friction of the large screw in its nut. If such is the case, the f primary screw 17 reaches thebottom of its travel 'while the secondary screw '20 is still extended somewhat. Provision is made forsuc'h occasion,

the primary screw being rotatable in its bottomv position, and being held against rotation only by frictional means arranged to oppose rotation of the screw more strongly in one direction-than end 23. During lowering, the screw 17 tends to rotate counter-clockwise as viewed in Fig. 5.

. r When clear of the ribs, such rotation is permitted.

One of the lugs 18 strikes the projecting end 23 of the spring 22 and th e'springby reason of the direction in which it is wound, is' relatively free to rotate within the standard 2, so that the screw 17 rotates with the nut 5 and causesflowering of the secondary screw 20. When the jack israised the screw 17 tends'to rotate ina clockwise direction, as viewed in Fig. 5, but one'of thelugs 18 then strikes the other'fac'eof the projecting end 23 of the spring. This tends to expand the springoutwardly, andftlie free'end 24 strongly engages the inner face of the standard 2, and provides considerable resistance against rotation of the screw .17. This resistanceis sufficient to insure rotation of the nut 5 relative to the screw 17, thus raising the screw to a. point where the lugs 18 engage the ribs '19. The lugs 18 are beveled offatjthe tops as indicated in Fig; 4, so as to insure'that they will not lock underneath the ribs 19. "1 A spring 25, similar in all respects to the spring 22, is placed inthe standard above the ribs 19,-

but inthe "opposite direction as will be seen by a; comparison of FigsA and 5; When the screw 17 reaches the top ofits travel, one of the lugs .18 engages theprojecting end 26 ofthe spring 25 "andby reason of the direction in which the spring is wound, it is'readily rotated clockwise with the screw 1-7 as the secondary screw 20 is threaded outwardly.

-When the jacl; is lowered, one: of the lugs 18 engages the opposite face of the spring end 26,

'whereupon the-free end '27 of the springbears eddownwardly.

strongly against'tlie inn'er face ofthe standard and thus insuresthat thefscrew 1'7 will be thread- I have illustrated and described a present pre ferred embodiment of the invention as applied to an automobile lack. It will be understood,

however, thatthe'invention is not limited to the form shown',.bu t may beptherwiseembodied within the scope ofithe following claims.

' 1. A jack comprising a standard, a lifting screw movable within the standard, arotatable put for raising and lowering the screw, means on the standard for positively limiting rotation; of the screwrelative to the standard during a portion of its movement, and friction means for limiting rotation of the screw during another portion of its movement, including a spring coiled in said standard having means engageable by the screw te nding'to coil or-uncoil the spring, depending on the direction "ofscrew rotatior'nso that the spring rotates freely in the standard or engages it frictionally.

, 2. A jack'comprising a standard, a lifting screw movable within the standard, a rotatable nut for raising and lowering the screw, means on the standard" for'positively limiting rotation of the screw relative to the standard during a portion of its movement," and friction means for limiting rotation of the screw during another portion of its movement, includinga resilient member lying within said standard having means engageable by the screw tending to expand or contract the resilthe standard or rotates freely therein.

I 3. A jack comprising a standardya lifting screw movablewithin the standard, a rotatablc nut forraising and lowering the screw, means for positively limiting rotation of the screw r elative to the standard during a portion of itsmovement, and a spring coiled in said standard having means engageable by the-screw tending to coil or uncoil the spring, depending on thedirection of screw rotation, so that the spring rotates freely in the standard or engages it frictionally.

4. A jack comprising a standard, a lifting screw movablewithin the standard, a rotatable nut for p raising and lowering the screw,a lug on the screw,

the standard'being shaped to engage the lug during'a' portion ofthe travel of the screw and limit rotation during such portion of the travel, and a spring coiled in said standard having means engageable by the lug tending to coil or uncoil the spring, depending on the direction of screw rotation, so that the spring rotates freely in thestandaid or engages, it frictionally.

5. A jack comprising a standard; a lifting screw, a rotatable nut for raising or lowering" the screw means forypositively' limiting rotation of rection of screw rotation, so 'thatthe springs ro- Itate freely in the standard or frictionally enage it.

the screw during the intermediate portion of its the screw during the intermediate portion of its I travel, and springs coiled within said standard at fthe endsjof' the travel ofthe screw, saidsprings, "having :means engageable by the screw tending ;to coil or uncoil the springs, depending on the ditraveLand friction means for limiting the'rotation of the screw atthe 'top and bottom portions of its travel, including'springs coiled within said standard adjacent the ends of the screwtravel, said springs having means engageable by the screw tending to coil or uncoil them, depending-- 'on'the direction of screw rotation, so that the springs rotate freely in the standardor frictionally engageit, therespective springs being effective to engage the standard frictionally on [rotation of the screw in opposite directions.

'7; ,A jack comprising a standard, a lifting screw, a rotatablenut for raising or lowering the screw, means for positively limiting the rotation of the screw during a portion of its travel, friction means'for limiting rotation of the screw at the top of its travel, including a spring coiled within the standard at the top of the screw travel,"

having means engageable by the screw for coiling or uncoiling the spring on rotationofthe screw in opposite directions whereby thespring rotates freely in the standard orengages it frictionally to restrain rotation of the screw in one direction.

8. A jack comprising a. standard, a lifting screw, a rotatable nut for raising or lowering the screw, means for positively limiting the rotation of the screw during a portion of its travel, friction means for limiting rotation of the screw at the bottom of its travel, including a spring coiled] within the standard having means engageable by the screw forcoiling or uncoiling the spring to permit free rotation of the screw in one'direction and frictionally'restrain it inthe'other'direc'tion.

9. A jack comprising a standard, a lifting screw, a rotatable nut for raising or lowering the screw, means forpositively limiting the rotation of the screw during a portion of its tra'veLfriction means for limiting rotation of the screw at r the top and bottom of its travel, including springs coiled within said standard having means engageable by the screw'for contracting or expandstandard, or; engage it frictionally. 10. The combination: with a nut for actuating the tube, of means for preventa 3. @ingthem, depending on'the direction of screw V rotation, whereby thesprings rotate freely in the v standard, a threaded tube reciprocable in the standardanda ing rotationofthe tube in the standard. during part of its movement, and a spring coiled in said f standard adjacent one end of the tube travel and having ineansengageable by thetube for coiling or uncoiling it, depending on the *diI'GCtiOII'Of 1 ,f

tube rotation'gwhereby the spring rotatesfr'eely'j I standard, a threaded tube therein, and'a nut surof tube rotation, so that thespring rotates freely in the" standard or engages it frictionally torestrain rotation of the tube inone direction.

HAROLD w. CLARK.

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