US732523A - Lifting-jack. - Google Patents

Description

No. 732,523. PATBNTED JUNE 3,0, 1903.

' w. H. cox.

i LIFTING JACK APPLIOATIOH FILED JAN. Z4, 1903. N0 MODEL.

' PATENT resented rune 3o, 1903.

OFFICE.

WILLIAM II. COX, OF VIRDEN, ILLINOIS. i

LIFTING-JACK.

SPECIFICATION forming part of Letters Patent No. 732,523, dated June SO, 1903.- e

Application filed January 24, 1908. Serial No. 140,411. (No model.)

To a/ZZ whom zit may concern:

Be it known that I, VILLIAM HJCOX, a citizen of the United States, and a resident of Virden, in the county Macoupin and State of Illinois, have invented a new and useful Iniprovement in Lifting-Jacks, of which the following is a speciiication.

My invention relates to an improvement in lifting-jacks, it being an object,among others, to provide a powerful lifting mechanism coinposed of few strong and simple parts so conlbined and adapted as to respond easily to the wislles of the operator in'manipulating the Jac Further objects are to provide a lifting-jack which will automatically lock itself securely in place when elevated, sustaining the weight lifted until it is desired to return the object lifted to its place, which return is accomplished by simply moving a-trip or cam lever and Athrowing the operating-lever to a predetermined position.

With these and other objectsA in view my present invention consists in certain novel features of construction and combinations of parts, which will be hereinafter described, and pointed out in the claims.

In the accompanying dawings, Figures l and 2 are views in side elevation with parts broken away to show different positions 'of the grip mechanism, one view. showing the operative position and the other Vthe release; and Fig. 3 is a view in side elevation of the opposite side of the gripping mechanism from that shown in Figs. l and 2.

Myimprovedlifting-jackcomprises a'standard l, supported at its lower lend ona suitable base 2 and provided at the upper end-with a handle 3. The lifting-hook 4 is preferably cast integral with a head 5, which latter is mounted to slide on the bar or standard l. The hand or operating Ylever G is pivoted -to the head or hook lby means of a'bolt or stud 7, provided for that purpose. The head, with its hook, is raised by the hand-lever through the medium of the following mechanism Two; grips 8 and 9 are chainbered out through the interior, as shown, and loosely mounted on the bar or standard, they being so mounted on the bar or standard as to admit of a slight rocking v motion. These grips are substantially alike in general construction and are mounted on the bar or standard in reverse positions-that is to say, with their outer ends'extending in opposite directions. On their lower edges they have a rocker formation, as at lO. In cach of these grips a recess l1 is formed, said recesses aording seatsV for the toothed clutchblocks l2 l2, which clutches are adapted to engage or bite the opposite edges of the bar or standard l alternately, as will be explained. A bell-crank lever 13 is pivoted. in each grip and held normally inward by a stiff spiral spring le, interposed between one end of the bell-crank lever and the shell of the grip. These levers to all intents and purposes are alike, except that one is larger and longer than contact with the bar or standard until this normal tendency is counteracted.

The lifting operation is as follows: As the hand-lever is raised itlifts the grip connected with it, which in the construction illustrated is the lower grip. `When the handlever is dey pressed the lower grip becomes clutched to the bar or standard and acts as a ifulcrum, so to speak, for the hand-lever in lift-ing the head and hook and the upper grip, which is carried by the head. Vhen the hand-lever is lifted, the head becomes the fulcrum of the hand or operating lever, the upper 'grip locking it automatically against downward movement on the bar or standard-and, as previously explained, the lower grip is in that way ele vated.- The movement of the hand-lever is from vertical to horizontal, or approximately so, and with the two motions, down and up, or vice versa, the fulcrum of the lever shifts v irtually from one grip to the other, or, to be more accurate, from the lower grip to the head, or, in other words, thev clutches of the two grips operate alternately to support the fulcrum. As the teeth of the clutches extend downward, the entire mechanism maybe lifted bodily7 at any time; but it can only be lowered under certain conditions, and these conditions are that the two grips must be rocked against the resistance of the springs 1i 14C out of their nor mal positions, so tl'iat the teeth of the clutches are thrown backward out of engagement with the bar or standard. This may be accomplished in various ways but as a simple means I have provided the cam 17, which is pivoted, preferably removably, to the head 5 in posi* tion when swung horizontally to release the clutch of the upper g'rip from the bar or standard. \Vhen thus released, in order to lower the movable. parts to the base of the bar or standard, or, in fact, to lower them at all, it is still necessary to release the clutch of the lower grip, and this is accomplished by raising the hand-lever to or almost to its extreme elevated position ,when it will lower the upper grip into contact with the lower grip, the rocker l0 will strike the lower grip at the clutch end, and by throwing the entire weight of the movable mechanism upon the lower grip at that point, which means shifting it from the end at which the bell-crank lever is pivoted to the opposite end, results in the release of the lower grip, and consequently the lowering of the entire movable mechanism.

From the foregoing provision it will be seen that the mere release of the upper grip by swinging the cam against it will not cause the parts to descend, thus perhaps suddenly dropping the weight when not intended, but it still .remains necessary to release the lower grip, which is donc by raising the hand-lever to vertical as a preliminary to lowering the mechanism.

From the foregoing it will be seen that the number of parts of my improved lifting-jack is reduced to a minimum and at the same time they are strong, simple in operation, most effectual in use, affording a powerful leverage capable of lifting the heaviest weight for which such an article is ever called into requisition.

It is evident that slight changes might be resorted to in the form and arrangement of the several parts described without departing Yfrom the spirit and scope of my invention,

and hence I do not wish to limit myself to exact construction herein set forth; but,

I-Iaving fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. The combination with a bar or standard and a head mounted to slide thereon, of a pair of grips mounted on the bar or standard, spring-actuated levers pivoted to each grip, one of said .levers also pivoted to the head, and an operatingdever to which one end of the other spring-actuated lever is pivoted.

2. The combination with a bar or standard, a head and grips mounted to slide thereon, of an operating-lever, and levers pivoted to opposite ends of the grips, 011e extending tothe head and the other to the operatin g-lever, and means for causing the grips to tilt on the bar or standard to grip the latter.

The combination with abar or standard, a head and grips mounted to slide thereon, of an operating-lever, and levers pivoted to the outer ends of the grips, one extending to the head and the other to the operating-lever, means for causing the grips to tilt on the bar or standard to grip the latter, and adjustable means on the head for shifting the weight of the latter to the opposite ends of the grips from which the levers are connected whereby to release and lower the grips and head by merely shifting the operatinglever to a raised position.

4. The combination with a bar or standard, of a head and a pair of grips having sliding connection with the bar or standard, of a le ver pivoted to thehead, bell-crank levers pivotall y connected with the head and lever, said bell-crank levers pivoted respectively to the outer ends of the two grips, sprin .in said grips for normally rocking the latter into position to cause clutch-teeth in the grips to normally engage the bar or standard.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

WILLIAM II. COX.

VitneSscs:

.'I'osnrn W. Evm-rrs, Guo. J. PATTIsoN, Jr.

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