Drafting utensil
United States Patent 2233481

This invention relates to drafting utensils, and more particularly to drafting guides, for instance, draftsmen's triangles. However, according to some important aspects the invention while illustrated as embodied in a draftsman's triangle should not be understood as being limited thereto,...

Helen, Kuehl
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Helen, Kuehl
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This invention relates to drafting utensils, and more particularly to drafting guides, for instance, draftsmen's triangles.

However, according to some important aspects the invention while illustrated as embodied in a draftsman's triangle should not be understood as being limited thereto, but to be broad enough to include besides straight-edged, also curved drafting guides, for instance, those known as French curves or the like.

It is a common experience in ink work when using the ruling pen along with, say, triangle and straight-edge, that uncontrollable ink splotches develop on the drafting surface, as the ink from the ruling pen spreads between the drafting surface and the triangle due to the adhesion of the ink, the damage causing great loss of time and requiring a tedious process of erasure and restoration.

Therefore, it is one object of this invention to provide a draftsman's guide or triangle whereby such trouble can be avoided.

According to one feature the drafting guide or triangle has means unitary therewith whereby it is adapted to be spaced from the drafting surface when applied thereto. It provides for a transparent overhanging edge portion spaced from the drafting surface, to guide the ruling pen, and adapted to overlie without touching at a line freshly inked and yet wet, the transparency of the overhanging portion enabling the draftsman to observe the extent to which a freshly inked line may be overlain by the guide while a new line is bei aong inked along the edge. By the same token this feature renders harmless some inadvertent slipping of the triangle over a freshly inked line.

According to another feature the working edges or edge portions of the triangle are undercut, except for the corners. Solid or relatively reinforced corner portions are provided to serve the dual purpose of avoiding breakage of the pointed corners of the triangle, and also to prevent disalignment of the triangle with regard to the straight-edge, in preventing the undercut portion of the triangle from creeping on to the straight-edge.

According to another feature the triangle is in the nature of an article of manufacture, in which the undercut is produced in various ways, one of them being by lamination.

According to another feature the horizontal depth, that is the dimension of overhang of the undercut portion diminishes gradually to zero at the corner portion of the triangle.

According to one embodiment, the triangle is manufactured of transparent homogeneous material, having milled into each edge portion an undercut that extends along each side of the triangle although terminating short of the re- '5 spective corners thereof. This provides relatively thin overhanging portions of relatively greater transparency. It also provides solid corner portions that are relatively safe against breakage and at the same time serve to guide the triangle with respect to the straight-edge.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description. In the following description and in the claims, parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit. In the accompanying drawing there has been illustrated the best embodiment of the invention known to me, but such embodiment is to be regarded as typical only of many possible embodiments, and the invention is not to be limited thereto.

The novel features considered characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of a specific embodiment when read in connection with the accompanying drawing, in which: Fig. 1 is a perspective view of the improved triangle having marginally overhanging sides or undercuts, and solid corner portions.

Fig. 2 is a perspective view to show the function of the undercut portions of the trianjgle.in use, the overhang being clear of an inked line underneath.

Figs. 3 and 4 illustrate one mode of producing the article as by lamination.

Fig. 5 is a plan view of the improved triangle, showing the guide function of its solid corner portions with respect to a straight-edge. The triangle according to Fig. 1 is shown to be of a solid piece of plane material, designated as a whole by the numeral 10, and it may be of a suitable homogeneous, transparent or semitransparent composition. Undercuts II, 12 and -50 13 are formed along the working sides of the triangle and they may have been milled into or otherwise produced in the material of the triangle. These undercuts extend along the working edge portions of the triangle, although terminating short of the respective corners thereof and in a manner to provide solid corner portions or relative reinforcements or ribs 14, 15, 16.

Due to their respective terminal faces 14a, 15a, 16a, these reinforcements or ribs serve the additional purpose of guiding or aligning the triangle with respect to the straight-edge 17.

The function of these guide faces provided at the corners of the triangle is more clearly illustrated in Fig. 5, showing the length of such a guiding corner face being designated by numerals 18 in alignment with the straight-edge 17.

In Figs. 3 and 4 the article is shown as being fashioned by way of lamination in that a layer 20 having cut-outs 21, is bonded to a triangular layer 22.

By way of another definition the triangle according to this invention has overhanging side portions 24, 25, 26, extending from a body portion 28, the thickness 27 of the overhanging portions being less than that of the body portion 28, and accordingly less than the thickness of the solid corner portions 14, 15, 16. On the other hand, the undercut thus created may be defined by the horizontal depth d and by the vertical depth or shoulder e thereof.

The manner of use of this article is substantially self-explanatory from Figs. 2 and 5. In Fig. 5 the triangle 10 is lined up against the straight-edge 11 on a drafting surface 23. All the potential working edges of the triangle are undercut in the manner shown and well suited for ink work in all positions of the triangle and with a ruling pen 24. Hence there is no danger of the base of the triangle setting against the straight-edge to creep up over the straight-edge.

In the practical use of this triangle it will be found that the ink does not spread underneath the overhanging edge portions thereof. Another advantage is that the overhanging edge portion may be allowed to overlie a wet inked line without splotching the same, as the line is being distinguished through the weakened thickness of the overhanging marginal portion of the triangle.

This practice enables the draftsman to save time, not only due to the effective prevention of ink splotches, but also in that he need not wait for certain closely spaced lines to dry, but may advance the triangle over a freshly inked line to the extent permitted by the horizontal depth of the undercut. This particular practice is more clearly illustrated in Fig. 2 showing a line 29 just being drawn by the ruling pen 24, and a line 30 previously drawn and now being overlain by, althrough spaced from the overhanging portion 21 of the triangle. A drafting surface or sheet is designated by the numeral 31,and and drafting board by the numeral 32. The freshly inked line 30 is shown to be visible through the overhanging transparent portion 27, and this transparency permits the draftsman the extent to which he may allow the line 30 to be etoverlain by the portion 27, so as to keep that line clear of the shoulder e of the undercut.

I claim: 1. A draftman's triangle of a thickness defined by a pair of parallel planes, comprising a body portion having overhanging working edge portions extending from said body portion substantially within the space defined by said planes, and 39 of a thickness substantially less than that of the body portion, and having extreme comer portions of a thickness substantially greater than that of the overhanging portion and also extending substantially within the space defined by said planes, said overhanging working edge portions being disposed intermediate respective corner portions.

2. A triangle according to claim 1, in which said corner portions provide comer faces substantially flush with the outer working edge of the respective overhanging portions.