US493766A - Drawing or plotting board - Google Patents

Description

UNITED STATES PATENT OFFICE.

GEORGE M. GRAHAM, OF CHICAGO, ILLINOIS.

DRAWING OR PLOTTING BOARD.

SPECIFICATION forming part of Letters Patent N 0. 493,766, dated March 21, 1893.

- Application filed August 5, 1892. $erial No. 442,249. (No model.)

To all whom it may concern.-

Be it known that I, GEORGE M. GRAHAM, a citizen of the United States, residing at Ohicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Drawing or Plotting Boards; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification.

This invention relates to drawing or plotting boards, for making drawings, plats, and the like in an accurate and expeditious manner; the object of the present improvement being to provide a cheap and convenient form of drawing or plotting board whereby the operation of drawing or platting in an accurate and rapid manner can be effected in an easy and ready manner. I attain such object by the arrangementof parts illustrated in the accompanying drawings, in which:

Figure 1, is a plan view of a board constructed in accordance with my present invention; Fig. 2, a cross section of the same, and Fig. 3, an enlarged detail plan of a corner portion of the board.

Similar numerals of reference indicate like parts in the different views.

As represented in the drawings the board consists of a raised marginal portion or rim 1, and a sunken central portion or body 2, to which the paper is attached in making a drawing, plat, &c. The surface of the raised marginal rim will be of some width as shown, and divided into squares, that are again subdivided to constitute a drawing scale along the different margins of the board, the arrangement being such that by means of a ruler any desired divisions can be drawn on the constituting a convenient protractor for laying 011' lines of any required degree.

The sunken formation of the central portion 2, of the board is to admit of the attachment of the drawing paper at a plane below that of the marginal rim, so that the paper attaching tacks will not interfere with the movement of the ruler in laying off a drawing, plat, &c. I

For ordinary uses a board having a scale on its right hand side and another on its lower side will be sufficient; I however prefer the arrangement of a scale on all four marginal surfaces of the board as illustrated in the drawings.

I am aware that prior to my invention,

drawing boards have been provided with scales along the side edges thereof. I therefore make no claim to such arrangement broadly, but

Having thus fully described my said invention, what I claim as new, and desire to secure by Letters Patent, is

A drawing or plotting board, formed with a sunken central portion, of a square form, and a raised margin surrounding the four sides of the sunken central portion, the top of the margin being plane, and provided with scales, consisting of a series of subdivided squares, substantially asset forth.

In testimony whereof witness my hand this A 1st day of August, 1892.

GEORGE M. GRAHAM.

In presence of ROBERT BURNS, Gno. H. ARTHUR.

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