US78167A - Improvement in mfting-jack - Google Patents

Description

I To ALL WHOMI'T MAY OONOERN:

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Letters .Patent No. 78,167, dated May 19, 1868.

IMPROVEMENT -IN LI'rIIIiIc-IEOIL` ilgeidgthule ritmes tu it 113m mitm met uns matting um nf the same.

Be it known that I, JAMES WILKINSON, of Bowling Green, in the county of Pike, and State of Missouri, have made certain new andy useful Improvements in Lifting-Jacks and I do hereby declare that the following is a full and clear description thereof, reference being had to the accompanying drawings, and to the yletters of reference marked thereon.

This invention relates to a. 1ifting-jack wherein a movable fulcrum is actuated by the lever that raises the` weight in a vertical direction at each successive stroke of the said lever, in such a manner as to maintainI the fulcrum at a uniform distance from the weight to he raised;

l v To enable those skilled in the art to make and use my improved jack, I will proceed to describe its construction and operation.

Figure 1 of the drawings is a front elevation of the improved jack. l Figure 2 is a transverse sectional elevation of the same.

Figure 3 is an inside elevation of one of the fulcrum-posts, and showing sections of'the fulcrum-pins in their sockets.

The fulcrum-posts A'are to be erected upon a platform, A1, and have their top ends connected together by4 a cap-piece, A2., Grooves a a a3 a4 are to be made in the' inside faces of the posts A, for the reception of the fulcrum-pins 6. The grooves a? a3 are formed in aregular succession of segmental curves, and have steps at the points x ze, at the intersection of two curves. These steps cause lthe'bottoms of the said grooves al a3 to present a serrated section in elevation'.V The steps m a; are cut squarely into the post in such a mannonas to allow the pins b to rest upon them, and above each step the bottoms of the said grooves'arebevelled forward sucently far to form the next step above. Between the points :c a: the grooves al as are segments of circles, the segments in a1 being described from the points x in a.3 as centres, and the points :c in a in turn servingfor centres from which to describe the segments of a3.

The `double fulcrum-head `B has four bearing-pins, b, which fitin the grooves a a in such a, manner as to 'rest on the steps :cof said grooves, as shown .best in g. 3. These pins 'are arranged to slide into cavities in the head B, as shown by thebroken-out `section in' iig. 1, which also'discloses springs behind the said pins, that force the pins forward into the grooves, but yield sudiciently to allow the pins to .retreat into the head, when moving up the incline between the steps, as is also shown in fig. 1. vA lever, C, is 'inserted into the'hedB, and as its outer end is worked alternately up and down, first one side of the fulcrnm-head, .and then the other, is raised so as to' allow the pins b to rest on the steps x, and in this manner both the lever and its fulcrum are raised with the weight, which may be placed on -top of the p-rop D, or attached to the hook When'thefulcrumblock shall in this-manner have been raised to the top of the grooves al a", the pins b will be pushed forward into the grooves a2 a, in which they will 4then slide down to the bottoms of the said grooves, and thence again I, into al er1-where theraising operation may be repeated.

Having described my invention, what I claim, is y 1. The posts A A, when provided with the segmental serrated grooves al a3, and combined with a movable fulcrum, B, substantially in the manner and for the purpose herein shown and described.

2. I claim the fulcrnm-head B, whenY provided with the spring-bearing pinsb, and otherwise arranged, as'

herein set forth and described.

In testimony of which invention, I hereunto sct my hand, in presence of JAMES WILKINSON. Witnesses:

M. RANnoLrI'I, GEO. W. Hnannr.

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