GB179059A - Improvements in or relating to instruments for drawing parallel and radial lines - Google Patents

Abstract

179,059. Harter, G. April 7, 1920. Rulers; centrolineads.- Consists of a parallel or radial ruler comprising a straight-edge or body 2 provided with bearings for a spindle on which are mounted rollers 1, the rollers being provided with peripheral needlelike points to grip the paper, as described in Specification 164,065. As shown in Figs. 5 and 7, each roller is composed of rings 12, 13 filled in with cement &c. 14 in which the needles 11 are embedded. One or both of the rings are made cylindrical to bear on the paper, or a separate bearing-roller independent of the wheel may be mounted in close proximity to it. One or more circles of needles may be provided on each wheel. Fig. 8 shows a ruler for drawing radial lines, the rollers 1, 1<a> being mounted on separate spindles which are connected by gearing 22 - - - - 28. the gear ratio being variable by moving the idler 27. The roller 1<a> is splined on its spindle 21 so as to be axially adjustable thereon. This device may be adapted for describing circular arcs by the attachment of a pencil point or pen. Rollers as described may be used in rulers having two sets of rollers at an angle to each other and with those having means for indicating the displacement and/or locking means for preventing displacement. A straight edge may be adjustably secured to the body of the ruler.