US 560329 A
Description (OCR text may contain errors)
J. SH'ERMANL STONE LEWIS.
' No. 560,329. Patented May 19, 1896.
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ANDREW a.smmm,rnu'ro-umavusmumou. D C
UNITED STATES PATENT OFFICE.
JAMES SHERMAN, OF CAMBRIDGEBOROUGH, PENNSYLVANIA.
SPECIFICATION forming part of Letters Patent No. 560,329, dated May 19, 18 96.
Application filed January 28,1896. Serial No. 577,150. (No model.)
To all whom it may concern.-
Be it known that I, JAMES SHERMAN, a citizen of the United States, residing at Gambridgeborough, in the county of Crawford and State of Pennsylvania, have invented certain new and useful Improvements in Stone- Lcwises; and I do hereby declare the following to be .a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.
This invention relates to stone-lewises; and it consists in certain improvements in the construction thereof, as will be hereinafter fully described, and pointed out in the claims.
The invention isillustrated in the accompanying drawings as follows:
Figure 1 shows the lewis in place (the dotted lines indicating the stone) in a long mortise. Fig. 2 shows the lewis in a short mortise.
A A marks the grip-irons of the lewis. They are formed with the tenons a and the extensions a, having, preferably, the general directions shown. The upper ends of the extensions are provided with hooks a, on which are hooked links B B. The links B B loop a central link 0, the three forming an inverted.
toggle-joint, the result of which is to draw together the upper ends of'the extensions when the force of the lift is applied. The grip-irons are placed counter to each other and each is counter-fulcrumed by the other on the edge opposite the gripping edge of the tenon. The edges of the grip-iron where fulcrumed, as at a a are curved and form what I term rolling fulcrum-su rfaces, against which the drawing-together force of the toggle is exerted to effect the spreading of the tenons in the dovetail mortise. By this method of fulcruming the grip-irons the fulcrum can be brought nearer the ends of the tenons than can be effectively done by means of fixed pivots and the full complement of metal at the fulcrum (the vital point) is attained.
It is desirable in these devices to have the tenons contact at both the top and bottom of the dovetail mortise, as at y y, in order that there will be no playing or sawing of the lewis in the hole. The rolling fulcrumsurface at the point of fulcrum accomplishes understood.
this result to some extent, as a greater spread of the tenons is made with less change of angle than is effected with a stationary pivot. Where, however, the variation in the size of the mortise exceeds the capacity for compensation just stated, a spreader D is inserted, as shown in Fig. 1. By having several sizes of spreaders any mortise within the capacity of the lewis can be readily and accurately fitted.
, The operation of the device will be readily The grip-irons are placed in the mortise and the links B B placed over the hooks a 0, The lift-chain is attached to the link 0. The effect of the force of the lift is to draw together the extensions a and spread the tenons a, which are in this manner securely fastened in the stone. The lewis can be readily removed when the pressure from the lift is released.
What I claim as new is 1. In a stone-lewis, the combination of a pair of grip-irons each having a tenon and extension, and each counter-fulcrumed on its edge opposite the gripping edge of its tenon by its companion grip-iron intermediately of the extension and tenon; and means operating upon the extensions to impart the gripping action to the tenons.
2. In a stone-lewis, the combination of a pair of grip-irons each having a tenon and extension, and each counter-fulcrumed on its edge opposite the gripping edge of its tenon by its companion grip-iron intermediately of the extension and tenon one of said grip-irons having where fulcrumed a rolling fulcrumsurface; and means operating upon the extensions to impart the gripping action to the tenons.
3. In a stone-lewis, the combination of a pair of grip-irons each having a tenon and extension, and each counter-fulcrumed on its edge opposite the gripping edge of its tenon by its companion grip-iron intermediately of the extension and tenons and each of said grip-irons having Where fulcrumed a rolling fulcrum-surface; and means operating upon pair of grip-irons each having a tenon and extensions to impart a gripping action to the extension, and each counter-fulcrumed on its tenons. IO edge opposite the gripping edge of its tenon In testimony whereof I affix my signature by its companion grip-iron intermediately of in presence of two Witnesses.
the tenon and extension; a spreader placed JAMES SHERMAN. between the grip-irons where fulcrumed t0 Witnesses: adjust the tenons to operate at different dis- WM. D. HILL,
tances apart; and means operating upon the .T. K. HATFIELD.