US686591A - Lifting-jack. - Google Patents

Description

N0. 686,55". Patented NOV. 12, IQUI. W. H. COX.

LIFTING JACK.

(Application filed July 11. 1901.

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(No Model.)

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UNITED STATES PATENT OFFICE.

WILLIAM H. cox, or yIRDEN, ILLINOIS.

, 'LIFTING-JACK.

SPECIFICATION forming part of Letters Patent No. 686,591, dated November 12, 1901.

Application filed July 11, 1901. Serial No. 67,889. (No model.)

To all whmn it may concern.-

. Be it known that I, WILLIAM H. 00X, a citizen of the United States, residing at Virden, in the county of Macoupin and State of Illinois, have invented a new and useful Improvement in Lifting-J acks, of which the following is a specification.

My invention relates to an improvement in lifting-jacks, the object being to provide a lifting-jack composed of as few parts as possible and which will be quick in action and effectual in the performance of its functions.

With these and other objects in view my invention consists in certain novel features of construction and combinations of parts,

which will be hereinafter described,and point:

ed out in the claims.

In the accompanying drawings, Figure l is a View in side elevation of my improved lifting-jack in one of its positions in full lines, another position being shown in dotted lines; and Figs. 2 and 3 are sectional views showing different positions of the clutch mechanismt Fig. 4 is a view taken from the opposite side, from that shown in Fig. 1, and Figs. 5 and 6 are detail views.

A A represents astandarderected from the base'l, to which its lower end is secured, and having a handle 2 secured to its upper end. Mounted to slide on the standard are the upper and lower' runners 4 and 5, respectively, which parts, with their respective locking mechanisms 'and'mode of operation, will now be described. The upper runner 4. is pref: erably made in the form of a single hollow casting, one portion' of its cavity constructed and adapted to receive'and slide upon the standard and other portions constructed and adapted to receive other parts of the operating mechanism. The. lower rear portion ofthis upperrunnerextends parallel with the standard, as at 6, and above this the runner extends rearward, and the rear wall 7 of this enlarged portion is; upon an incline, thus forming a wedge-shaped recess between said inclined wall and the adjacent edge of the standard; In this recess a wedge-shaped block 8 is located, it being adapted to wedge itself intothe wedge-shaped space when not otherwise hindered. This block has an open slot formed in its forward edge, the inner wall 9 of which slot 10 is rounded, as shown.

the edge of the standard. Aspiral spring 13 bears against a shoulder 14: on the lower end of block 8, with a tendency always to force the latter into the wedge-shaped recess. The lower end of this spring is held bythe seat15 in the upper end of a dog 16, and the latter is secured at the upper end 6 of the rear portion of the runner by means of a screw or pin 17, which extends through holes 18 18 in the runner and into a notch 19 in the back of the on the pin 21, and this hand-lever is provided with a cam 22, adapted to bear upon the lower end of the wall 7 when the hand-lever is swung upward todraw the block 8 downward against A hand-lever 20 is pivoted to block 8 7 the action of the spring from its extreme upwardposition in the wedge-shaped recess and to throw its lower end inward, so as to unlock or release the teeth of the gripping-block from engagement with the standard. As this handlever 20 is raised the block 8 is lowered against the action of the spring 13, and when once raised the lever is retained in that position bythe combined action of the spring, the

. block, and the frictional contact of the handlever on the lower edge of the wall 7.

Passing now to the lower runner 5, it also :is provided with a hollowed-out interior, a

portion of the walls of which is constructed to receive and fit as well as slide upon the standard A. In the upper portion of the rear wall a recess 23 is formed, and in this recess a steel gripping-block is held. This grippingblock is provided with a plurality of downwardly-projecting teeth 25 on its outside sur'- face in position to engage and grip the rear edge of the standard under certain conditionsnamely, when the forward end of the lower runner is tilted downward in the operation of raising the upper runner 4. This tilting of the forward endof the lower runner downward is effected by the outward swinging or vibration of the L-shaped pitman 26, which latter is pivoted at its angle to the forward end of the lower runner, as at 27, and

between the shorter end 28 of this pitman and a portion of the runner to which it is pivoted astiff spiral spring 29 is interposed, the function of which spring is to cause the downward tilting of the forward end of the lower runner and the biting of the teeth of the grippingblock in the recess 23 upon the standard. The upper end of the L-shaped pitman is pivotally connected with the operating hand-lever 30 at a point 31, and as the pitman extends into the recessed interior of the upper runner a curved slot 32 is formed in one side of the runner in the arc of a circle whose center is the pivot 33 of the hand operating-lever, and through this curved slot the wristpin which connects the pitman and hand operating-lever operates. In this way the parts are compactly assembled and protected from blows from the exterior, as the parts of the runners form housings for the pitman and other smaller parts. The upper runner has the usual horn or arm 34 upon which to receive the axle or other weight to be lifted.

The operation is as follows: Assuming that the runners are located at the lower end of the standard and it is desired to lift an object or to raise the runners to a lifting position, the hand-lever 20 is first dropped, thereby throwing the block 8 upward and inward, so that it is free to be actuated by the spring bearing against it. The hand operating-lever 30 is now raised and lowered. The downward motion has the effect of locking the lower runner to the standard and raising the upper runner, and when the hand operatinglever reaches its lowest position the two runners are farthest apart. When the hand operating-lever is raised, the upper runner is locked by the gripping action of the toothed block upon the standard and the lower runner is raised to the lower end of the upper runner. as often as the hand operating-lever is raised and lowered or until the upper runner shall have reached the highest point possible on the standard. It will be observed that the runners alternately grip the standard-first one runner and then the other and the stationary one is always the fulcrum for the movement of the other runner in the stepby-step motion described. When the runners have reached the desired height, they may be lowered by swinging the hand operating-lever into a vertical position, the handlever 20 having been raised. This causes the upper runner to strike a projection 38 on the rear upper surface of the lower runner, thereby tilting the lower runner sufficiently to cause a release of the teeth on the grippingblock from the standard and the dropping of the two runners, which will run smoothly down the standard.

It is evident that slight changes might be resorted to in the form and arrangement of the several parts described without departing from the spirit and scope of my invention, and hence I do not wish to limit myself to the exact construction herein set forth;

but,

Having fully described my invention, what These operations repeat themselves I claim as new, and desire to secure by Letters Patent, is-

1. In a lifting-jack, the combination with a standard, and a pair of runners loosely mounted thereon, and provided with clutching means, of a hand operating-lever fulcrumed on one of the runners, said runner having a slot therein curved in the arc of a circle whose center is the pivotal point of the hand operating-lever, and a pitman pivotally connected to the hand operating-lever and one of the runners, the pitman extending up into the interior of the runner to which the hand operating-lever is pivoted, and a wristpin which connects the pitman with said lever extending through the curved slot in the side of the runner so that the ends of said slot constitute stops for the extreme movements of the hand operating-lever.

2. In a lifting-jack, the combination with a standard, and a pair of runners loosely mounted to slide thereon, one runner having a toothed block held in position to engage the standard and the other provided with a similar block which is spring-actuated, and a handlever pivoted in position to regulate the adjustment of said block, of an L-shaped pitman pivoted to one runner, a spring interposed between one end of the pitman and a portion of the runner whereby to cause the runner to vibrate, a hand operating-lever pivoted to one of the runners and to which one end of the pitman is pivotally connected.

3. In a lifting-jack, the combination with a standard, of a pair of runners having sliding connection therewith, the lower runner havinga toothed gripping-block in one of its walls and an L-shaped pitman pivoted at its forward end, with a spring interposed between one end of the pitman and a portion of the runner, the other runner having a block therein which carries a toothed gripping-block, a spring bearing against the block for normally holding the latter wedged against the standard; a hand-lever pivoted to the block and provided with a cam for releasing the block from the standard when the lever is swung in one direction, and a hand operating-lever pivoted to one of the runners and to which the pitman is pivotally connected.

4. In a lifting-jack, the combination with a standard, of a pair of runners loosely mounted thereon, a hand-operated lever pivoted to one runner, a pitman extending from the runner and cause both to slide freely downward upon the standard when the hand operating-lever and the hand-lever are both raised to their extreme upward positions.

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

WILLIAM H. COX.

Witnesses:

GEO. J. PATTISON, J12, GEO. H. HILL.

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