Ruler with sliding transverse portion - has lengthwise groove for spring protrusion on transverse portion

摘要

The ruler consists of a base portion on which a transverse portion slides, and the transverse portion consists of an angle-piece. Its one arm s a downwards facing spring protrusion, extending for the entire length of its outside lengthwise edge, which slides in a lengthwise groove in the top face of the base portion. When assembled, the top of the base portion along one side can be chamfered (12), allowing the transverse portion to be pressed down onto it so as to draw a line, while the guide slot can be of dovetail section.