GB208211A - Improvements in apparatus for making perspective drawings - Google Patents

Abstract

208,211. Mobbs, G. I. W. Sept. 11, 1922. Drawing-boards.-Apparatus for use as a centrolinead, tee-square, and protractor in making perspective drawings directly to scale comprises a part A fixed temporarily or permanently to a drawing-board or table top by drawing-pins N<1>, N<2> or screws, and provided with two curved edges T<1>, T<2> corresponding to two vanishing points and with a straight edge R, and a part B provided with curved edges t', t<2> engaging the edges T', T<2> to enable vanishing lines to be drawn by blades E, E<1>, and with a, straight edge F engaging the edge R to form a tee-square. The part A may be at either side of the board and the part B is reversible and similar on both sides. One vanishing point is indicated by a projection K. The part B carries reference diagrams W and scales such as perspective scales G, H, true scales V<6>, degree scales V<5>, and scales V of vanishing points of degrees, whilst the part A carries a degree scale V<4>, a scale V<1> determining vertical heights, and a straight true scale V<2> cooperating with a scale on the vertical edge F. The curved edges t<2> project on both sides of the part B above the extension carrying the edge t<1>, and, when the edges t<1>, T' are used together as shown, the edge T' is raised by one or more springs C beneath the part A. The drawing- pins N', N<2> are passed through thin extensions of the part A to avoid projecting parts.