Motor driven valve for gas appliances - has reduction gearing driven by motor to open valve and spring bias for rapid closure

摘要

The motor driven valve for gas appliances has a closure member which is spring-biased into the closed position. A reduction gearing (18-30) enables the motor to open the valve slowly. The gearing is self-locking so that the spring bias cannot dominate the motor. The gearing can be locked against rotation by a latch (37) while the motor is de-energised. Release of the latch during the de-energised state of the motor enables the valve to close rapidly. The latch may be a pawl electromagnetically engageable with the gearing but biased into the withdrawn position.