| 摘要 |
<p>A motor is connected to a reversing switching and a rechargeable electrical energy storage device such as a high value capacitor (SC1, SC2). On application of power to the apparatus (ie. during normal operation), the motor can be driven in forward and reverse directions to drive a valve, and on removal of power from the apparatus, charge stored in the storage means drives the motor to bring the valve to a rest position. The apparatus is self-contained, and avoids the need for an over dimensioned motor which would be necessary to drive against the normal self-return spring. <IMAGE></p> |
