Adjustment device for contact springs - causes free sprint end to be deflected beyond elasticity limit for given spring cross section

摘要

A contact spring pretensioned more than the design limit is deflected by a controlled feeler of a pickup against its pretensioning. Its movement is continuously monitored by measurement of force and travel, and the spring characteristic is recorded and compared with the required characteristic. When the same value is reached in both characteristics, pickup movement is stopped. The pickup is in the form of a rectangular moving coil in an air-gap between a cylindrical permanent magnet and a soft magnetic circuit. An arc of circle with a small radius test sensor acts on the free end of a contact spring clamped near the system axis. Rotary movement is evaluated by a device generating analogue or digital signals converted into electrically evaluated signals.