US723518A - Drawing-board and t-square. - Google Patents

Description

PATENTED MAR. 24, 1903.

E. ELLISON. DRAWING BOARD AND T-SQUARE. APPLICATION TIL?!) 00T.4, 1902.

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I0 MODEL.

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t 5 Height, near Manchester, in the county of '15 for keeping the head of the T-square always- I 5 of the board it has been the practice to use UNITED STATES PATENT OrFIcE.

EMILY ELLISON, OF IRLAMS-O-TH-HEIGHT, NEAR MANCHESTER, ENGLAND, ASSIGNOR OF ONE-HALF TO \V. T. ELLISON & COMPANY, LIMITED, OF IRLAMS-O"-TH-HEIGHT, NEARMAN CHESTER, ENGLAND.

DRAWING-BOARD AND Ii-SQUARE.

SPECIFICATION forming part of Letters I'atent NO. 723,518, dated March 24, 1903.

Application filed October 4,1902.

To all whom it may concern:

. Be it known that I, EMILY ELLISON, a subject of the King of Great Britain and Ireland, residing at 53 Bolton road, Irlams-o-th- Lancaster, England, have invented new and useful Improvements Applicable to Drawing- Boards and T-Squares to be'Used Therewith, of which the following is a specification.

This invention relates to improvements upon that-type of drawing-boards and T squares used by engineers, architects, surveyors, and other draftsmen and lecturers wherein magnetic appliances are employed in close contact with the working edge of the drawing-board.

According to my invention I propose to plane or otherwise form a groove-say about half inch or more and about three-sixteenths of an inch wide (either more or less to suit my purpose) in the left-hand and lower edges of the drawing-board and to insert therein and secure by means of pins or otherwise a strip of soft iron of such a width that its outer edge may project slightly beyond the edge of the board. This method of fixing the soft-iron strip will not only prevent any liability of its becoming loose, bntas it is in its strongest possible form will not be liable to get out of true, even if the board warps, and will also render it more-durable. Also hitherto in applying a magnet to the head of the T-square to cause its adhesion to the edge 7 a straight or curved magnet which has its .poles a considerable distance apart. Thus its range of working is very limited if, say, you are working at the top or bottom of your board the current is broken, owing to one of itspoles being oif the strip, therefore rendering the magnet inefiective. To remedy these defects, Ipropose according to my invention in the first place to use a number of small 5 horseshoe or Umagnets permanent or else-- trio-say two or more to suit my purposewhich I entirely embed or inclose in the head of the T-square, with the exception of their poles, which may. either be flush or; project so slightly beyond the surface of the wood on Serial No. 125,906. (1% model.)

the inner or working side of the head, and to so arrange these magnets above and below the center of the blade, that however near the latter may be moved to the top or bottomof the board, there will always be one or more magnet or magnets in elfective action,

and therefore the T-square will not be liable to become loose accidentally and fall from its position on the board.

On the accompanying drawings, which form part of this specification, Figure 1 is a face view, Fig. 2 an edge view, and Fig. 3 a section, of the edge of the drawing-board with a soft-iron strip shown as applied thereto. Fig. 4 is a face view, Fig. 5 an edge view, and Fig. 6 a sectional view, of the head of the T'- square made according to my invention. Fig. 7 is a view, on a reduced scale, showing the improved drawing-board and T-square together as they appear when in use.

The head of the T-square for use with this drawing-board (see Figs. 4, 5, and 6) I prefer to make of two thicknesses of wood f g, glued or cemented together and fastened with screws h. (See Figs. 4, 5, and 6.) In one of these piecesof wood I embeda series of magnets-say, for example, five- 0f a horseshoe or U form, so as to be flush'with the surface, and then I apply the other piece and fix it firmly thereon, as described, sothat the magnets are entirely inclosed in the wood with the exception of their poles, which are flush with the outside of the wood or project only very slightly therefrom on the working edge of the head. According to Fig. 6 I prefer *to make the magnets laminated by two, three, or more layers of steel 'U-shaped plates, (according to the weight or size of the T-square,) as they are stronger in their action, but they may also be of a'solid bar bent to the U shape.-

It will be evident that when the head of the 'T-square is made according to my invention I and provided with a series of magnets, as de' scribed,when used in connection with a draw; ing-board or lecture-board, blade may be raised to'th'e upper edge of the paper, so that a considerable portion of the head' projects above the top of the board and,- that those magnets which are below the edge of the board will have their circuits unbroken roe (see Fig. 7,) the 5 J and will retainthe square in position even if the board should be placed in almost a vertical position or. the most acute angle.

I claim as my invention 1. A T-square having a number of horseshoe-magnets embedded in the head, side by side longitudinallythereof, the poles of all of which extend to and are exposed at the surface of the inner edge and are adapted to be rested against the edge of the drawing-board,

in combination with a drawing-board having an iron strip at its edge, substantially as described.- I

2. A T-square, having a number of laminated horseshoe-magnets embedded side by side longitudinally in the head, the poles of all of which extend to and are exposed at the surface of the inner edge, in combination with a drawing-board having a bar of soft iron set into its edge and pins passing through the board and iron to hold it in place, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EMILY ELLISON.

Witnesses: v

GEORGE DAVIES, J No. HUGHES.

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