The TZF/TZM Series is designed for machines/work cells where access to a hazardous work area must be controlled until safe conditions exist. Their solenoid-latching feature permits locking a machine guard until dangerous conditions, which may exist immediately after removal of power, have abated. Solenoid-latching may be controlled by a time delay, motion detector, position sensor or other suitable component. The unit features independent actuator key (guard) position and solenoid-latching monitoring contacts. These permit the prevention of machine restart until the guard is closed and the solenoid-latching pin is in the locked position. The TZF/TZM Series consists of an electromechanical safety interlock switch with "positive-break" contacts and a locking actuator key. In addition, the TZFS model features an auxiliary manual unlocking device the latter provided to aid in installation and for use in the event of a power failure (when using the "unlocking by solenoid" model).