초록 ▼

An actuator, preferably a linear actuator, a reversible motor which drives an adjustment element via a transmission. To increase the self-clocking ability of the actuator, the actuator is equipped with a coil spring which has its one end secured to a rotating element in the actuator so that the spri

An actuator, preferably a linear actuator, a reversible motor which drives an adjustment element via a transmission. To increase the self-clocking ability of the actuator, the actuator is equipped with a coil spring which has its one end secured to a rotating element in the actuator so that the spring is carried along in the rotation on the cylindrical part, which is static in relation thereto. When the motor is turned off, and the load on the actuator tries to displace the adjustment element, the movement of the coil spring is blocked, and the coil spring is tightened around the cylindrical part.

대표청구항 ▼

The invention claimed is: 1. An actuator comprising a reversible motor, a transmission operatively connected to the motor, a spindle with threads, said spindle being operatively connected to the transmission to rotate the spindle multiple revolutions, a movable adjustment element having threads in

The invention claimed is: 1. An actuator comprising a reversible motor, a transmission operatively connected to the motor, a spindle with threads, said spindle being operatively connected to the transmission to rotate the spindle multiple revolutions, a movable adjustment element having threads in engagement with the threads of the spindle for moving the movable adjustment element along the spindle, a cylindrical part which is static, fixed and immovably mounted relative to the motor, a rotating element attached to an end of the spindle and rotatable by the motor, a coil spring with a first end secured to the rotating element, said coil spring being arranged on the cylindrical part and with a direction of winding such that the spring exerts a braking effect on the adjustment element in one direction of movement thereof in that the spring is tightly wrapped around the cylindrical part, said braking effect being adapted such that it may be overcome by the motor, and wherein an axis of the coil spring is in alignment with an axis of the rotating element so that the spring is carried along in the rotation on the cylindrical part. 2. The actuator according to claim 1, wherein the cylindrical part comprises metal. 3. The actuator according to claim 2, wherein the cylindrical part has core of metal provided with a plastic bushing thereon secured against rotation, at least on a part where the coil spring is arranged. 4. The actuator according to claim 2, wherein the cylindrical part comprises axially-extending strips of plastic on which the spring is arranged. 5. The actuator according to claim 1, wherein the cylindrical part forms part of a bracket fixedly mounted on the front end of the motor. 6. The actuator according to claim 1, wherein the transmission comprises a worm drive with a worm and wherein said rotating element is a worm wheel, said coil spring having its one end connected to the worm wheel. 7. The actuator according to claim 6, wherein the coil spring includes a radially outwardly bent end at its one end secured to the worm wheel. 8. The actuator according to claim 6, wherein the coil spring includes an axially bent end at its one end secured in a hole in the worm wheel. 9. The actuator according to claim 1, including a heat-conducting metal shield around the coil spring to convey heat away from the spring. 10. The actuator according to claim 1, wherein the coil spring comprises metal wire, and wherein the wire has a four-sided, circular or oval cross-section.