Scribing machine for marking circuit cards - has cutter driven by coil spring running between two ball bearings to give axial feed

摘要

The scribing machine is principally used in connection with equipment for testing printed circuit cards. If a circuit passes the test the machine cuts a mark on the card, typically a circle, to indicate correct status. An economical scribing machine can be made by employing a coil spring (5) as a flexible shaft between the motor (7) and the cutter (1). This allows cutter and motor axes to be at right angles without the need for special gearing. To give the necessary axial feed to the cutter the spring runs between two ball bearings (8) whose diameter is larger than the spring pitch. As the spring turns it drives the cutter onto the surface of the card. At a certain pressur pressure the balls (8) are forced outwards against their retaining spring (9), and the coil spring jumps a pitch. The use of readily available items such as coil springs and ball bearings ensures economical construction.