| 摘要 |
Actuating means for a valve, particularly of the plug type, which is movable between operative positions by successive modes of movement, one being axially and another rotationally, wherein a rotatably driven nut is in threaded engagement with a valve stem, a cam controlled device acting respectively at predetermined positions of the nut to permit relative movement of the nut so as to move the stem in the axial mode, and to connect the nut and stem for unitary rotation so as to move the stem in the rotational mode, guiding means being provided for the stem, so that it cannot be moved in a subsequent mode until the prior mode has first been completed. |
