Actuator having an associated locking device and torque limiter
The invention relates to an actuator comprising a stationary structure and an actuating element that is movable relative to the stationary structure, a device for locking the actuating element in position which is mounted on the stationary structure and has a state for locking and a state for releasing the actuating element. The locking device comprises, successively, a stress limiter and at least one locking element so arranged as to be butting against one surface of the actuating element, in order to oppose a motion of the actuating element in a predetermined direction. The actuator comprises a member for controlling the locking device in the releasing state thereof and a member for resiliently returning the locking device to the locking state thereof.
1. An actuator comprising a stationary structure and an actuating element that is movable relative to the stationary structure, with a device for locking the actuating element in position being mounted on the stationary structure and having a state for locking and a state for releasing the actuating element, characterized in that the locking device comprises, successively, a stress limiter and at least one locking element so arranged as to rest on a surface of the actuating element so as to oppose, by butting up against a motion of the actuating element in a predetermined direction, in that the actuator comprises a member for controlling the locking device in the releasing state thereof and a member for resiliently returning the locking device to the locking state thereof.
2. The actuator according to claim 1 , wherein the stress limiter comprises a friction element which is applied against a surface integral with the stationary structure and which carries the locking element.
3. The actuator according to claim 2 , wherein the returning member is so arranged as to apply the locking element against said surface of the actuating element and the controlling member comprises a solenoid and supply means so arranged that the powered solenoid maintains the locking element off said surface against the returning member.
4. The actuator according to claim 3 , wherein the controlling member comprises a lock which is movable between a release position in which the lock forms a stop preventing the locking element from resting against the actuating element and a holding position in which the lock lets the locking member free to rest on the actuating element under the action of the returning member, with the solenoid being so arranged as to move the lock towards the position in which the locking element is maintained in the release position.
5. The actuator according to claim 4 , wherein the movable lock and the locking element cooperate through cam surfaces so arranged that, when the lock is moved from the release position of the locking element to the position thereof maintaining the locking member, whereas the locking member is in contact with said surface of the actuating element, the lock causes the breaking of contact between the locking element and said surface.
6. The actuator according to claim 4 , wherein the lock is movable in a direction parallel to the actuating element.
7. The actuator according to claim 1 , wherein the locking element is mounted on the stationary structure and acts on a surface of the stress limiter.
8. The actuator according to claim 1 , wherein the actuating element is so mounted as to pivot relative to the stationary structure.
9. The actuator according to claim 1 , wherein the actuating element comprises a transmission line having a relatively high speed shaft and a relatively low speed shaft, and the locking device is so mounted as to act on the relatively high speed shaft.
10. The actuator according to claim 1 , wherein the locking element is a ball, a roller or an eccentrically pivoting jaw.