US1714548A - Lifting jack - Google Patents

Description

May 28, 1929.

EQE. CLINE ET AL LIFTINGJACK File d Jan. 19, 1927 4 Sheets-Sheet 1 May 28, 1929.

E. E. CL INE r AL LIFTING JACK Filed Jan. 19, 1927 4 Sheets-Sheet 2 Ma 28, 1929. E. E. cum: ET \L 1,714,548

- I LIFTING JACK Filed Jan. 19, 1927 4 Sheets-Sheet 3 Q a: n a

Q a M anyeml o'v 'mes? If Holmes Rota,

May 1929. E. E. CLINE ET AL LIQFTIBIG JACK Filed Jail. 19, 1927 4 Sheets-Sheet 4 Patented May 281, 1929 EARL E. GLINE AND ERNEST VT. HOLMES, 0E CHATTANQOGA, TENNESSEE, QSSEGNORS TO ERNEST HOLMES COMPAATY, 0L CHATTANOOGA,TENNESSEE, A CORPORATION OF TENNESSEE.

merino JACK.

Application filed January 19, 1327. Serial No.1 162,107.

This invention relates to liftin jacks and particularly to acks of the portable wheeled type used in lifting automobiles;

One of the objects of the'invention is the provision of ajack in which the lifting force is transmitted'tothe load through frictional torque the value of which is automatically determined by the load and is in directproportion to the load.

Another object of the invention is to construct a ack of the type described in which the load acts to check its own descent while being lowered that it is impossible for the load to be dropped should the handle of the jack any time get out of the control of the operator.

' Still another object of the invention is the provision of a jack in which the lowering of the load is effected by reducing the frictional 'coeflicient of the powertransmitting means, said frictional coefficient being at once restored to the original value'at which the load is sustained, when the speed of the descending" movement of the power transmitting means exceeds that of the load loweringn'iovement of the handle, so that the lowering of the load is accomplished by a numberof Successive load-releasing pulls upon the ack ia'ndle, dependingin amplitude upon the relative angular speeds the handle movement and that of the power transmitting means. Another object of the invention is to-pro-f videa jack in which the height of the lifting element may be at any time determined'with precision without the lost motion. inherently it in ratchet checked lifting devices. ,ther objects of the invention will appear as the following description of a cnibmliment thereof proceeds.

In the draiin'gs, in which the same refer ence characters are used in the several views to signate identical parts l ures 1. 2 and 3 represent, in sequence,

sections constituting the plan view of a jack preferred,

racing the principles of the present inis a broken side elevation, partly ative limit mission mechanism and parts mounted adj a cent thereto; 7

Figure 10 is a perspectiveview of 'one of the lifting rockers; and V i Figure 11 is a-secti'on onthe'line 1111,

Figure 7," looking in the direction of the arrows;

The present inventionis'an improvement of the invention disclosed in the pending application of Ernest W. Holmes, Serial Number 66284;, filed Nov. 2, 19725, and the present disclosure follows, to some extent, the details of construction*disclosed in connection with the invention of said pending application. Therefore, those features which are fully treated in said pending application will bebut incidentally narrated in the present descrip'tion, in the interest of brevity I Referring now in detail to the several figures, thenumerals l and 2 represent'the side members of the jack which,'together withthe rear aXle'3, constitute'the frame of the jack, supported'at the rear by wheeled journalled on the axle, and forwardly, that .isto say, at an intermediate point in the jack, by casters'5 turningon substantially vertical aX s and bearing against caster-plates "6 riveted orotherwise suitably'secured' to the frame members 1 and 2, with a spacing plate 7 therebetween. A liftingvarm 8 is pivotally mounted upon the. frame at axial points 9 and 10, said arm carrying adjacent its outer end the li'ft-ingpost 11 upon which, the loadengaging platform 12 is swivelly mounted,- A pair of curvedliftingrockers 13 are pivotally mounted'a'djacent the-outer end of" the lifting arm, said rockers resting-freely upon a roller 14 ournalled upon a stationary rod 15 secured in the side ofthe frame members, the curvature at the lower ends of said lifting rockers preferably being such as to permit'said' rockers passing between the ground and the axle when the lifting arm is in its sup1nepos1t1on The lifting-{rockers are flanged as shown at 16 in Flgure 10, and' the frame is-provided with'inwardly pro-' stop being thus provided so that the lifting rockers cannot be elevated beyond their oper-J 1 ,hains 19 or other suitable flexible connec merated are common to thej ack described and claimed in the pending application to Holmes hereinbefore mentioned and no novelty is predicated of vthem alone, but only in combination with the device now to bedes'cribed.

A bar bridges the side frame members 1 and 2 preferably slightly forwardly of the casters 5, said bar being preferably non-rotatably supported-by the frame members, and in turn, affording support for certain rotatable elements, thesame being shown on an enlarged scale in Figure 8.

These members include a drum '21 upon 7 which a chain 22 is windable, said chain betermines thelifting rangeof the ack. 1 It is,

ing received by the single end 23 of a Y-shaped link, the divergent ends of which are secured to the chains 19. The chain 22 is preferably 3f such length as to wind completely around the drum'once, and this length of chain" dehowever, not essential to the invention to specify the exact length of the chain for it may be made of greater or less length than the circumference of the drum and still fulfill its purpose as an operative connection between the transmission means and lifting requirements without defeating the spirit of the invention. The drum 21 is provided, with arecesstransacted by a pin-way 2 1-, said re cess being adapted to receive the first link of the chain 22, a pinpassing through link and being enlarged or otherwise made fastin said pin-way.

- The drum 21 is formed to one side with .a disk 25 of relatively large diameter having aliat face 26. It is also formed preferably with recessor rabbet 2? affording a seat for anti-friction bearings 28. An annular check-plate 29 is arranged in juxtaposed position to the face 26 of the disk 25, a fric tion facing 30 preferablyintervening. The check platc 29 is rotatable relatively to the drum and axially shiftable as well so that it may be said to float with respect thereto. The check-plate is formed with aiperipheral flange 31, the interior wall of which rides uaon the bearings 28 said flan e bein formed eXteriorly with ratchet teetlri'l2 havmg the abrupt shoulders thereof directed against the direction of rotation ofsaid cheekplate. e

The check or holding pawl is rotatably mounted upon a bar 50 mounted transversely of the frame members to the rear of the checkplate 29. Saidpawl presses withconstant resilient pressure against said check-plate through the tension of spring 51. Said pawl is uni-directional in the periphery of its effect upon the'direction of rotation of the check-plate, permitting it to move for-- ward under tension with the lifting movement of the ack and holding it against retro- 2 de rotation when the load is held, or during the descent of said load.

The disk 25 is. formed with a hub 83 sur- "rounding the bar 20 and projecting through the central opening in the annular checkplate '29 upon whic the latter freely move endwise through a slightrange of movement as will presently appear. externally provided with a thread of deep and gradual pitch. A nut of relatively large diameter is secured upon said hub having a corresponding.'interengaging thread.

facing 35 of anthfriction material is preferably interleaved between the check-plate 29 and the nut 34. The effect of said nut when screwed upon said hub in one direction to'force the disk 2-35, check-plate 29 and disk 30 together, increasing the coefficient of friction between said members so that they move together as a unit. l/Vhen the nutis screwed in the opposite direction its effect is to reduce the coeiiicient of friction bet-ween This hub is said members so that they may moveinde bar 20, as shown, when the jack handle is escillated the arms 37 and 38 of the pawl will oscillate in arcs concentric to the bar20 and, therefore, concentric to the nut 34:. The cast ing l0 is provided at an intern'iediate point with. an arm 41 affording means which, in cooperation with aspring l2 enables the pawl 36 to be selectively biased in either direction. WVhen said pawl is so biased that'the aunt-38 is in contact with the teeth 36 of the nut, the parts are in position for the lifting operation.

When the pawl is biased so as to engage the arm 37 with the teeth 36 the parts are in the load lowering position. The arm 41' is preferably formed with a socket 4:3 in its outer end within which the rounded end of a rod 44 freely seats, said rod having a fixed collar 45 against which one end of the spring 42 abuts, the outer end of said rod passing through a transverse strap member lfi'between which and the collar 45 the spring is held in compressed relation keeping the end of the rod 44; seatedin the socket of the arm 41 regardless of the position of said arm. It

-will be observed from Figure 5. that the arm gular relation, but by swinging the casting.

40 so as to cause the point of contact between said rod and arm 41 to pass tothe other side of a straight line connecting the axis of rotation of the casting 40 and the point at which the rod '44 passes through the strip 46, the relation of angularity between said arm and rod will be reversed, the arm 41 and with it the casting and pawl being thus definitely maintained in biased positionto one side or the other. I

The casting 40 is rocked by means of a pull rod 47 pivotally connected to a lug 48 formed on said casting, said pull rod being. preferably passed through an aperture in the strap member 46 and extending to a convenient posit-ion at the endofithe jack handle.

In operation, with the pawl 36 in the position shown in Figure 7, downward movement I of thehandle of the jack will rotate the nut 34 in a clockwise direction as viewed in Figure'7, screw said nut inwardly against'the check-plate 29 and in turn pushing the checkplate endwise into frictional engagement with the disk 25 of the drum, the parts being wedged into unitary relation, so that the drum 21 rotates with the nut 34, the chain 22 being wound upon the drum and the lifting means operated to elevate the load. In the lifting operation the jack handle, may be moved through any convenient are, providing it is great enough to move the check-plate through a distance equal to the circumferential length of one of the ratchet teeth 32, and the load will be elevated to that extent. The jack handle may be operated in any position, from one approaching thevertical, to aposition close to thefioor, rendering the jack adaptable for all contingencies met with in use, it being. equally operable close to a wall or beneath a low hung trunk carrier or other obstruction on the automobile ordinarily giving but little room for operation of the jack.

The load is sustained through frictional cont-act between the check-plate 29 and the disk 25, the pawl 49 holding the check-platefrom retrograde movement during relative movements of the ack handle The pitch of the thread between the nut and hub 33 is so designed that for the capacity load for which the Jack is designed, the nut will stick when the jack handle is released so that there will be no frictional slippage between the checkplate and the disk 25.

When it is desired to lowerthe load. the

push rod 47 is manipulated to bias the pawl 36 in the opposite direction so that the arm 37 comes into engagement with the teeth on the nut 34. Raising of the ack handle then has the effect of unscrewing the nut. When the nut begins to recede from the check-plate, the frictional coefficient between the checkplate 29 and disk 25 begins to decrease so that the drum turns in an unwinding direction let- .;,ting the load'down a little. However, just as soon as the angular speed of the devicein winding begins toeXceed the angular speed of the jack handle, the disk screws the hub 33 again into the nut so that the frictional cociiicient between the parts increases again to the point where the loadis held. A further lifting of the jack handle again reduces the coei'hcient of friction causing furtherloweringo'f the load, which may again cause an increase in the coefficient of friction between the disk and check- Jlate, again checking the 'descent of the load, and so on, the load descending operation being, in general, a succession of upward pulls of thej ack handle against the resistance of the friction of the several parts engendered by the load. Of course, it is dis cretionary with the operator of the jack just how farhe shall let the load down at one time.

If the load is not heavy, he may lift the jack handle through a considerable arc and letthe load down through a proportionally great distance. One of the characteristic advan tages of the invention is that if the jack han' dle be inadvertently let go of by the operator, insteadof it flyingupward with great force,

at the same time letting the load drop, the

' means, an attemptto work the jack with the nut screwed out away'from the check-plate might result in a back and forth oscillatory movement of the nut with the handle due-to the pressure of the pawl 36 against the teeth of said nut under the urge of the spring 42,

so that the load would never be raised. order to obviate this drawback, we have provided a light frictional brake for the nut 34, ensuring, when the jack handle is operated,

, ice I relative movement between the pawl 36 .and

the nut. This brake consists of a lever 52 riding upon the bar 50hav1ng one end preferably cup'ped as shown at 53in Figure 7, the. cupped end housing a spring 54 which bears against the spacing plate 7. The opposite end of the lever forms a brake shoe 55 which bears against the periphery of the nut with a pres I v the yoke 56 which rests upon theupper face ofthebar50.

Although a safety stop 18 is provided on the rocking levers to'prevent-the jack being raised beyond a safe limit, yet said stop is sub ect to the strain of the entire power multiplicationofwhichthe jack-is capable; In

order to avoid this undue. strain, a normal working safety stop is provided so that the stop 18 acts .only as an emergency or auxiliary stop in the event that the ordinary or service stop should become at any time inoperative. The service stop comprises a pawl .55 which, for convenience, may be journalled upon the same rod 20 which carries the ack operating mechanism. Said pawl has an angular end 56 which projects through an opening 57 in the'jack frame of such size as to permit the pawl to have a limited range of movement about its. axis. The angular end of the pawl 56 lies withinfan annular groove 58 formed inthe outer face'of the nut 34, said groove being discontinuous one point, shown in Figure '7, projecting web 59 being formed at this point engageable by the pawl in either direction of rotation of the nut to inhibit further rotation of the nut in that direction. The amount of lost motion between the aperture 57 and the angular end 56 of the pawl isat least equal to the wid h of the web 59, so that the pawl may move through this disi tance when struck by the web in either direction of rotation of the nut, thus permitting the nut to rotate through a, complete arc of 360 degrees. It is obvious that the stop afforded between the pawl 55 and web 59 is subject merely 'to the direct leverage of the jack handle and not to the power multiplication provided by the drum and its appurtenant parts. r

,The other features disclosed in the draw-- ing, but not described in detail in the present specification, are common to my hereinbefore mentioned pendingapplication, and no further reference to'them appears necessary.

The operation of the jack according to the present invention is obvious from the preceding description of the several features. However, it should be understood that this ack combines the-principles and advantages of a ratchet ack and screw jack. In the load-lifting operation it acts as a ratchet jack, lifting the load step by step through distances coniinensurate with the space between adjacent teeth on the check plate. In lowering the load, it acts as a screw jack, being adjusted to minute differences in. elevation. Furthermore, it possesses the inherent function of a friction brake in the load-descending movement, the drum screwing into the check-plate and pushing the latter into frictional unity with. the nut whenever the angular speed of the drum in the load-lowering movement exceeds the angular speed of the jack handle when the latter is operated to lower the load.

It is thus apparent that the load cannot escape from the operator as is the case with ordinary jacks when the handle is inadvertently re leased, since immediately the pressure of the load gives the drum superior speed which screws it at once intothe floating check-plate,

forcing the latter into unitary contact with ment or the load.

While we have iii-the above description disclosed what we believe to be a perfect'and pia tical embodiment of our invention, yet it is to be understood that the details of construction by means of which the inventive principle is illustrated are not to be considered as limitativein their effect upon the scope of the invention, but merely by way of example, the invention residing in the broader principles of operation except where restricted by the express terms of the appended claims. r

We claimz In a jack of the type in which the lifting member is connected to the operating lililiS by flexible connection, a rotatable ruin upon which said flexible connection is wint able, and'a nut screwable into frictional u er, applied to said nut, to said drum. I 2. In a jack of the type in which the lifting member is connected to the operating by a flexible connection, a rotatable drum upon which said flexible connection is windablc, a nut screwable into frictional unity with said drum for transmitting power, applied to said nut, to said drum, and means for rotating said nut selectively in either direction. 3; In jack of the type in which the lifting member is connected to the operating means by a flexible connection, a rotatable drum upon which said flexible connection is windable, a nut screwable into frictional unity with said drum for transmitting to I said drum power applied to-said nut, and

means to prevent unwinding movement of said drum while said parts are in frictional unity.

4. In a jack of the type in which the lifting member is connected to the operating means by a flexible connection, a rod, a drum journalleo upon said rod upon which said flexible connection is windable, and a nut rotatable relative to said rod screwable into frictional unity with said drum for transmittin power a" lied to said nut to said drum.

5. In a jack of the type in which the lift ing member is connected to the operating means by a flexible connection, a drum upon which said flexible connection is windable,

and a nut interscrewing with said drum to l ity with said drum for transmitting powb in said carts into frictionalunit for transmitting to said drum power'applied to said nut.v

6. In a jack of the type in which the lifting member is connected to the operating means by a flexible connection, a drum upon which saidflexible connection is windable, a nut interscrewing with said drum to bring said parts into frictional unity, for'trans niitting to said drum power applied to said .a check plate interposed between said nut and drum for transn'iitting power from one to the other, and means act ng upon said check-plate toprevent unwindmg movement of said frictional unit parts when said power applying means is released. I

' 8. In a jack of that type in which the'lifting member is connected to the operating member by a flexible connection, a drum on which said flexible connection is .windable, a nut to which power is applied interscrewing into frictional unity with said drum, a check plate floatably mounted between said nut and drum for transmitting power from said nut to said drum, said nut acting to push said check plate against said drum to frictionally unite said parts when the nut is rotated in a load-lifting direction, and said drum acting to push said check-plate against said nut to frictionally unite said parts when the angular speed of said drum exceeds that of said nut, in a load-lowering direction.

9. In a jack of that type in which the lifting member is connected to the operating member by a flexible connection, a drum on which said flexible connection is windable, a nut to which power is applied interscrewing into frictional unity with said drum, a check plate floatably mounted between said nut and drum for transmitting power, from said nut to said drum, said nut acting to push said check plate against said drum to frictio-nally unite said parts when the nut is rotated in a load-lifting direction, said drum acting to push said check-plate against said nut to frictionally unite said parts when the angular speed of said drum exceeds that of said nut, in a load-lowering direction, and means to prevent movement of said check-plate in a load-lowering direction.

10. In a jack, a rod functioning as a sup- )ort, a winding drum journalled on said rod,

aving a friction face in a plane transverse to its axis of rotation, and an axially ex tended threaded portion, a cheek-plate freely journalled on said extension both for rotation and endwise movement, having friction, faces on its opposite sides, a nut threaded on said extension having a friction face on the side adjacentsaid check-plate, said nut and drum being approachableto or recessible from said check-plate to make or break frictional contact therewith upon relative screwing movement between said nut and drum,

and means to limit the rotary movement of said check plate to rotation in the load-lifting direction of said drum.

11. In. a jack, a rod functioning as'a support, a winding drum journalled on said rod, having a friction face in a plane transverse to its axis of rotation, and an axially extended threaded portion, a check-plate freely journalled on said extension,-both for rotation and endwise movement, having friction faces on its opposite sides, a nut threaded on said extension, having a friction face on the side adjacent said check-plate, said nut and drum being approachable to, orreoessible from said check-plate, to make or break frictional contact therewith, upon relative screwing movement between said nut and drum, teeth on said nut, an operating handle, and a reversible pawl, engageable with the teeth on said nut and actuatable by said handle for operating said nut in either direction.

12. In a jack, a rod functioning as a support, a winding druinjournalled on said rod, having a friction face in a plane transverse to its axis of rot tion, and an axially extendedthreaded portion, a check-plate freely journalled on said extension, both forrotation and endwise movement, having friction faces on its opposite sides, a nut threaded on said extension, having a friction face on the side adjacent said check-plate, said nut and drum being approachable to, or recessible from said check-plate, to make or break frictional contact therewith, upon relative screwingmovemerit between said nut and drum, teeth on said nut, an operating handle, a reversible pawl, engageable withthe teeth on said nut and actuatable by said handle for operating said nut in either direction, and means for biasing said pawl in either direction. I

13. In a jack, a rod functioning as a support, a winding drum journalled on said rod, having a friction face in a plane transverse to its axis of rotation, and an axially extended threaded portion, a check-plate freely journalled on said extension, both for rotation and endwise movement, having friction faces on its opposite sides, a nut threadedvon said extension, having a friction face on the side adjacent said check-plate, said nut and drum being approachable to, or recessible from said check-plate, to make or break frictional contact therewith, upon relative screwing movement between said nut and drum, teeth on said nut, an operating handle, a reversible pawl, engageable with the teeth on said nut, and actuatableby said handle for operating said nut in either direction, and a yielding toggle for biasing said pawl in either direction.

14. In a jack, a load-lifting train of mechanism including a holding ratchet, controlling ratchet and a cooperating. screw, the holding ratchet acting to hold the load in the step-by-step stages of its ascent, the controlling ratchet coacting with the screw to permit the progressive descent of the load.

15. In a ack, a loaddifting train of mechanism including a holding ratchet, a controt ling ratchet and a screw having a load sustaining element, the holding ratchet acting to hold the load in the step-by-step stages of its ascent, the controlling ratchet coacting with the screw to permit the progressive dcscent of the load, and a friction brake between the holding ratchet and said lead sustaining element and checking the descent of the load when the angular speed of the load-sustaining element of the screw exceeds that of the controlling ratchet. I

16. In a ack, a load-lifting mechanism, arotatable member operatively connected to said load-lifting mechanism,- having a friction face in a plane transverse to its axis of rotation, and an axially extended threaded portion, a check-plate freely journalled on said, extension, both for rotation and endwise movement, having friction faces on its opposite sides, said check-plate being toothed, a pawl engaging the teeth on said checkplate limiting it to unidirectional movement in a load-lifting direction, a nut threaded on said extension having a friction face on the side adjacent said check-plate, said nut and drum beingapproachable to or recessible from said checkplate to make or break frictional cont ct therewith, upon relative screwing movement between said nut and drum, said nut being toothed, a reversible pawlengageable with said nut and means for applving power to said nut to rotate it in either direction.

17. In a jack, a load-lifting mechanism, a rotatable member operatively connected to said load-lifting mechanism, having a friction face in a plane transverse to its axis of rotation, and an axially extended threade portion, a check-plate freely journalled' on said extension, both for rotation and endwise movement, having fr'ictionfaces on its opposite sides, said check-plate being toothed, a pawl engaging the teeth on said check-plate limiting it to uni-directional movement in a load-lifting direction, a nut threaded on said extension having a friction face on the side adjacent said check-plate, said nut and drum being approachable to or recessible from said cheek-plate to make or break frictional contact therewith, upon relative screwing moveme t between said nut and drum, said nut be toothed. a reversible pawl engageable with said nut, means for applying power to said nut to rotate it in ei'therdircction, and a brake acting upon said nut with a friction superior to that of the reversible pawl.

18. In a jack, a load-lifting mechanism, a rotatable member operatively connected to said load-lifting mechanism, havinga friction face in a plane transverse to its axis of rotation, and an axially extended threaded portion, a check-plate freely journalled on said extension, both. for rotation and endwise movement. having friction faces on its opposite sides, said check-plate being toothed, a pawl engaging the teeth on said check-plate limiting it to uni-directional. movement in a load-lifting direction, a nut threaded on said extension having a friction face on the side adjacent said check-plate, said nut and drum being approachable to or recessible from said check-plate to make or break frictional contact therewith, upon relative screwing movement between said nut and drum, said nut being toothed. a reversible pawl engageable with said nut. means for applying power to said nut to rotate it in either direction, said nut being formed with an annular groove transected by a projecting web, and. a pawl on a relatively fixed part of the j acl-I projecting into said groove and engageable by said web, forming therewith a stop to limit rotation of said nut in either direction.

In testimony whereof we have hereunto set our hands.

EARL E. CLINE.

ERNEST W. HOLMES.

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