Draughting machine with two straight edges - supported by two steel tapes which are guided by rollers to ensure equal travel

摘要

A draughting maching has two mutually perpendicular straight edges mounted on a boss attached to a link. The link has each end attached to separate flexible tapes. Each tape passes over a guide roller mounted on a shaft and is then wound onto a spring loaded drum. Gears ensure that both the tapes move exactly the same distance when the straight edges are moved so that each straight edge remains parallel to its original position.