| 摘要 |
<p>An actuator having a body (3) with a central chamber having diametrically opposed inlet (4) and outlet ports (5) and a plug (18) within the chamber having a transverse passage (19) therethrough and an upstanding stem (21). Seal means on the plug are in sealing engagement with the chamber walls about the inlet and outlet ports. Means closing the top of the chamber through which the plug stem extends in fluid-tight fashion. The actuator comprises a hollow cylindrical yoke (27) the lower end of which is operatively affixed to the plug valve with the plug stem extending axially into the yoke. A valve stem (36a-d) is rotatively mounted at the upper end of the yoke and has a lower threaded portion (36b) extending axially into the yoke. The valve stem is threadedly engaged with a drive cam (69) non-rotatively mounted within the yoke and axially shiftable by the valve stem within the yoke. The lower portion of the drive cam has a diametrically opposed identical pair of sloped drive slots (73, 74) therein and is received in the axial bore of a coupling (56) and is affixed thereto by a drive pin (77) passing through the drive cam drive slots with its ends mounted in diametrically opposed perforations (75,76) in the coupling. The upper end of the plug stem is non-rotatively affixed to the cylindrical coupling. The coupling has diametrically opposed cam slots (61, 62) formed therein. The yoke supports a cam follower (67, 68) for each cam slot. The cam slots are so configured that upon turning the valve stem in one direction, the plug in its valve-open position will be simultaneously partially lowered and turned 90 DEG and thereafter lowered without rotation to its valve-closed and sealed position.</p> |
