| 摘要 |
PURPOSE: To prevent the axial movement of a shaft capable of being used as a shaft locking or a shaft manual operating device. CONSTITUTION: A manual indicator 32 fitted to the above or the outer end of a valve stem 22 is made up of an engaging means engaging to the outside end of the stem 22 and a locking means consisting of a ball nut, screw shaft and balls. The nut and the one side of the shaft is held not to be rotated, and the others are rotatably held. Further, the locking means and a spring 30 engaging both with a first fixed cylinder and with a second rotating surface are provided, and a spring releasing means is provided so that the relative rotation in one direction is prevented between both surfaces and also the axial movement of the stem 22 is allowed. |
