US2134688A - Erasing shield - Google Patents

Description

Nov. 1, 1938.

" WITNESSES.-

"r. FLETCHER ERASING SHIELD Filed July 15, 1957 Theodare INVENTOR;

i "Zeicher MTORNEYS.

Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE Richard D. Ward, tVilmington, Del.

Application July 15, 1937, Serial No. 153,703

4 Claims.

This invention relates to erasing shields; and it has reference more particularly to erasing shields intended for use by mechanical and architectural draftsmen. The erasing shields heretofore made primarily for stenographers were not altogether satisfactory in making erasures on drawings, due to the arrangement of the erasure openings in them which allowed of very little space for placement of the fingers. It was therefore impossible to hold such shields without contact of thefingers, through some of the erasure openings with the sheet being rubbed. One of the aims of my invention is to obviate the above drawback. which desideratum is realized in practice as hereinafter more fully disclosed, through provision of an erasing shield having the configuration of a sector with erasure holes of different lengths, widths, and shapes of which the greater number are distributed along radial lines so spaced angularly as to provide ample areas between them for the fingers.

Another object of my invention is to extend the usefulness of an erasing shield having the foregoing attributes, by providing it with scale graduations along its straight edges and/or along its curved edge for service as a combined square, or angle, measuring instrument and protractor.

Other objects and attendant advantages will appear from the following detailed description 30 of the attached drawing, wherein Fig. I shows,

in plan, an erasing shield embodying the present improvements; and

Fig. II is asectional view of a shield taken as indicated by the numerals II-II in Fig. I.

35 As herein illustrated, the erasing shield of my invention has the configuration of a sectorto be more exact, of a quadrant-which may be fashioned by die stamping or in any other convenient manner, from relatively thin sheet material, preferably metal. At the corner, the shield is provided, as shown, with a small sectoral erasure opening beyond the latter with an arcuate concentric slot-like opening 2, and beyond said arcuate opening with radially-arranged lines 3, l, 45 5, and 5 of openings which, it will be observed, are well spaced angularly so that ample areas I, 8 and 9 are left between them for placement of the fingers in holding down the shield to the avoidance of contact with the sheet being rubbed. It is to 50 be further noted that the elongate openings 3a-6u; respectively of the series. 3-43 are of different lengths and widths, the opening 3a square at both ends, and the opening 50!. rounded at one end, while the openings 4a and 6a are dif- 5 ferently tapered at one end. The openings 311-451), on the other hand, are all square, but of different sizes, and the openings 3c--6c all circular but of various diameters. Accordingly there is afforded a choice of shapes which will serve for all erasing requirement likely to be met with in practice.

In order to enhance the usefulness of my improved shield, I have further provided it as shown, with scale graduations along its straight edges iii and ii as well as along its curved edge edges in and H may be in accordance with either the English or the metric systems, while those at the curved edge may represent angular degrees in circular measure. Depending upon the dic- .tates of practice, the straight edge corrugations may be provided to the exclusion of the graduations along the curved edge, and vice versa.

The shield of my invention thus further takes on the functions of a square or angle, a linear measuring device and a protractor.

While, as hereinbefore stated, my improved shield is intended for use more particularly by draftsmen, it is not necessarily restricted to such use since it may be employed by stenographers,

'bookkeepers, etc, without sacrifice of any of the advantages pointed out.

Having thus described my invention, I claim:

1. A combined erasing shield, angle and protractor fashioned to the configuration of a sector from relatively thin sheet material, with scale graduations along its straight and arcuate edges, and having erasure openings disposed along lines radial to the corner of the angle.

2. A combined erasing shield, angle and protractor fashioned to the configuration of a sector from relatively thin sheet material, with scale graduations along its straight and arcuate edges, and having erasure openings disposed along lines radial to the corner of the angle, and corresponding to definite graduations along the arcuate edge.

3. A combined erasing shield, angle and protra-ctor according to claim 1, wherein the openings in the several radial lines are of different lengths, widths and shapes.

4. A combined erasing shieldangle and protractor fashioned to the configuration of a sector from relatively thin material, with scale graduations along its straight and arcuate edges, a small sector shaped opening of corresponding configuration in the corner of the angle, and other openings of different lengths, widths and shapes arranged in lines radial to the corner angles.

THEODORE FLETCHER.

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