US137333A - Improvement in claw-bars - Google Patents

Description

UNITED STATES PATENT DFFIGE. I

W ALTER S. TERHUNE, RIDGEVVOOD, N. J ASSIGNOR OF ONE-FOURTH 7 OF HIS RIGHT TO THOMAS ALDRIDGE WESTON, OF SAME PLACE.

IMPROVEMENT IN CLAW-BARS.

Specification forming part of Letters Patent No. 137,333, dated April 1, 1873; application. filed June 7, 1872.

To all whom it may concern: I

Be it known that I, WALTER S. TERHUNE, of Ridgewood, in the county of Bergen and State of New Jersey, have invented an Improvement in OlawBars, of which the followin g is a specification:

My invention consists in a sliding fulcrumblock dovetailed in a groove in the heel of the bar, both the block and the groove being provided with corresponding segmental proximate bearing-surfaces, as hereinafter described.

In the drawing, Figure 1 is a perspective view of my improved pinch-bar, shown also in changed position by broken lines. Fig. 2 is an elevation, showing the slotted portion of the bar in section. Fig. 3 is a perspective view of the segmental fulcrum-block removed. Figs. 4 and 5 are sections across the heel of the bar and block, showing equivalent mechanical devices for securing the latter in its seat.

I form the heel of the bar A with a longitudinal recess or groove, b, the bed of which is of segmental or convex form, as shown, into which I fit a block, 0, the upper surface of which is concave, corresponding with the convex part of the groove, the length of the block being only about one-half of that of the groove to admit of the bar having a sliding motion with relation to the block when used, the lat ter remaining stationary. The block is formed with dovetailed sides, as shown in Fig. 4, and the sides of the groove swaged to it so as to form a loose fit, which will admit of the free movement of one part with respect to the other, and yet prevent the bloc}: from becoming disengaged when the bar is handled.

The operation is as follows: When the bar is applied to use for the raising of a body the elevation of its opposite end brings the point in such position that the block 0 occupies the forward part of the groove b. As the body is raised the convex bearing rolls within the concave face of the block, which remains a stationary bearing, the heel of the bar sliding meanwhile and increasing the length of the short arm of the lever, thus raising the load higher and quicker than with a stationary fulcrum.

I am aware that fulcrunrblocks have been pivoted to the heel of pinch or crow bars by a fixed axis, but this does not produce the result obtained by a movable or sliding fulcrum nor do I claim the devices set forth in Letters Patent'No. 78,669 of June 9, 1868; but

I claim as-my invention- The segmental sliding fulcrum-block G, in combination with the convex-faced groove b b in the heel of the bar A, all constructed as herein shown, for the purpose set forth.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

WALTER S. TERHUNE.

WVitnesses J. H. BLAUVELT, J. J. Kmnsrnn.

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