Pneumatically operable drive unit with a temperature dependent irreversibly releasable lock joint

摘要

A drive unit is designed as a diaphragm drive with return springs for shifting an associated actuator, connected by a diaphragm plate and a driving diaphragm, into a safety position. The drive unit also includes actuating springs that are held in a compressed state by two nested sleeve-shaped counterbearings that are locked during normal operation and located coaxially with respect to the return springs. The lock is formed by a temperature-dependent joint.