| 摘要 |
A spring applied force actuator for a brake comprises an output member 1 movable from a first retracted position to a second, output (brake engaged) position by rotation of a sleeve 17 which is threadedly engaged with the output member a first, compression spring 4 by which can be generated on the output member an output force when the member is in its second position, first power means by which the first spring can be compressed and held until it is released to apply its stored force as an output force on the output member, a second spiral spring 10 on unwinding, rotates the sleeve 17 to move the output member from its first position to or towards its second output position, and second power means including motor 30 for rotating sleeve 17 by which the output member can be moved back from its second output position to its first position thereby, at the same time, winding-up the second spring. Subsequently the output member is moved back to its second output position upon release and unwinding of that second spring, and, if slack exists in the brake system when the spring 10 has unwound, by operation of the motor 30. The first and second power means include electric motors 5,30 and associated electro-magnetic brakes 42,31 and the energy stored in the springs is released by releasing the electromagnetic brakes. Means (15, 16, Fig. 3) is provided whereby the output member 1 will be moved back the same (brake clearance) distance on each operation of the actuator. <IMAGE> |
