| 摘要 |
The subject of the present invention is a system for automatically returning an element into a given position, for example a valve shutter 18. An actuator 56 causes the shaft 52 and the sun wheel 48 to rotate. The latter drives the satellite pinions 46 which roll on a fixed toothed crown 50. This movement drives, by means of the arms 44, the rotation of the rod 40 whose lower part forms a nut and bolt system with the piston 24. In the event of a breakdown, the actuator 56 is locked as is the sun wheel 48, but the springs 36 push the piston 24 downwards, which brings the shutter 18 into closed position. This movement causes the rod 40 to rotate: the satellite pinions 46 roll on the sun wheel 48 which is fixed and drive the crown 50 which, in this case, is unlocked. Application to the automatic closure of a valve shutter. <IMAGE>
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