GB738223A - Drawing instrument - Google Patents

Abstract

738,223. Drawing instruments. STARZYNSKI, S., and TRAVERS, M. July 1, 1954 [July 1, 1953], No. 18269/53. Class 97 (3). A drawing instrument comprises a body with at least one straight edge and, rotatably mounted on the body, an arm or like member having spaced holes therein and means for holding it in a fixed angular position. As shown in Fig. 1, the body 1 and arm 2 are made of transparent plastic. The edges 3, 4 of the body are both sealed. The arm 2 has a circular end portion 5 with a V-shaped peripheral groove interfitting with the edge of a socket in body 1. The socket is non-circular so as to pinch the portion 5 slightly to hold arm 2 in its set position. To draw a set of parallel lines, a pencil or stylus is placed in holes 6 in arm 2, and the instrument is slid with edge 3 held against a straight edge. The interval between the lines is adjusted by turning arm 2, using scales 7a, 7 which indicate the interval directly in inches and centimetres respectively. An angle scale 8 permits the instrument to be used as a protractor. To facilitate sliding, and to enable a pen to be used, the body and arm have a raised rib 10 and protuberances 9 on their under surfaces. In Fig. 2, a set-square is shown in which is mounted, in a circular recess in the base 11, a rotatable member 12 formed as a major segment of a circle. The recess 11 also accommodates a locking member 14. Member 12 has holes 16 for drawing parallel lines and the body has scales 17a, 17b for setting the interval. A slot 19 in member 12 may be set in conjunction with an angular scale 20 for drawing lines at any angle with respect to the edge of the set-square. According to the Provisional Specification, member 12 may be circular and looked by a screw.