US117761A

US117761A - John b

Info

Publication number: US117761A
Authority: US
Publication date: 1871-08-08
Anticipated expiration: 1888-08-08

Description

J. B.' FRANKLIN.

Drawing-Board.

117 761. Patented August a, 1871.

fEK @maag/fi.

UNITED STATES JOHN B. FRANKLIN, OF NEW YORK, N. Y.

IMPROVEMENT IN DRAWING-BOARDS.

Speeication forming part of Letters Patent No. 117,761, dated August 8, 1871.

To all ywhom it may concern: 1

Be it known that I, JOHN B. FRANKLIN, of the city, county, and State of New York, have invented a new and Improved Drawing-Board, and I do hereby declare that the following is a full, clear, and exact description thereof, which will enable others skilled in the art to make and use the same, reference being had to the accompanying drawing forming part of this specification, in which the drawing represents a perspective view,partlyin section, of my improved drawin g-board.

The object of this invention is to provide drawing-boards with concealed metallic stays or braces, whereby they will be prevented from warping and retained smooth when shrinking. The difficulty to be overcome consists chiefly in the necessity of keeping metal away from the surface of the board in order to permit the application of drawing-pins. My invention consists in interposing metallic strips or braces between the hard-wood edge-pieces and the board in the dovetail grooves at the ends of the board. The invention ccnsists also in the use, for large boards, of central hard-wood cross-pieces lined at the edges with L-shaped strips of metal.

A in the drawing represents the body or main portion of the drawing-board. 'B B are the hardwood edge-pieces applied to the ends of the board by being dovetailed thereto, as shown. O O are strips of dat or oval metal interposed between the contiguous faces of the pieces B and board A, so that they rest in the grooves of the latter, being thus concealed and not interfering with the surface of the board. The narrow metal strips O, being on edge Vwithin the board, eectually resist the warping of the same and keep it straight while it contracts or shrinks. The

edge-pieces are not glued or screwed to the board, and can be shifted to keep their ends always flush with the lower edge of the board.l Long boards I propose to strengthen by means of a central cross-piece, D, of hard wood, let into a groove at one face of the board A, and extending fromthe upper to the lower edge of same. Against the edges of this piece D, I place metal strips E E, L-shapedin cross-section, or of equivalent form, but not reaching to the surface of the board, as shown. These strips E, together with the cross-piece D, serve to stiften the board at the part where otherwise it would be most apt to bend. In order to counteract the weakening eifeet of the groove cut into the board for the reception of the cross-piece D, I propose to glue a piece, F, of hard wood against the upper edge of the board.

It will be observed that the entire board has :nothing but wood on both surfaces, and can, therefore, be used on either side. The metal strips O are or may be screwed to the edgepieces B, and the strips E may also be similarly attached to the cross-piece D.

Having thus described my invention, I claiin as new and desire to secure by Letters Patent- 1. The metallic strips O O, applied to a drawing-board between the edge-pieces B B and the body of the same, substantially as herein shown and described. f

2. The hard-wood cross-piece D, let into the grooved face ofthe drawing-board and combined with the metallic strips E, substantially as herein shown and described.

JOHN B. FRANKLIN.

Witnesses:

GEORGE W. MABEE, T. B. Mosi-IER.