| 摘要 |
<p>1533023 Valves EISENBAHN VERKEHSMITTEL AG 19 March 1976 [21 March 1975] 11265/76 Heading F2V A rotary ball valve, e.g. for discharge pipes on railway tank wagons, comprises a partspherical or spherical obturator 12, Figs. 1 and 2, co-operable in its closed position with packing 22 carried by a spring-biased sleeve 21. Moreover, the obturator is mounted on an eccentric portion of an actuating shaft 4 and is rotatably connected thereto by lost-motion means. The latter comprise a pin 15 co-operating with a groove 16 and a ball and notch coupling 19, 17. After removal of latching pin 11 the handle 7 is rotated through about 180 degrees from the valve-closed position shown. The shaft 4 initially rotates freely within the obturator over about 90 degrees until pin 15 abuts the other end of the groove 16 and ball 19 engages notch 17. During this portion of shaft rotation the obturator does not rotate but, due to the eccentricity of the shaft, moves along an arcuate path away from the packing 22, Fig. 4 (not shown). Rotation of the shaft over the remaining 90 degrees rotates the obturator to its open position, Fig. 3 (not shown), wherein a stop pin 13 on the obturator abuts second stop surface 14 and a stop boss 8 on the handle abuts the alternative stop surface 10. Subsequent movement of the handle in the opposite direction rotates the obturator via coupling 17, 19 until pin 13 once again abuts the first stop surface 14, whereafter further rotation of the shaft disconnects the coupling 17, 19 and the shaft rotates freely within the obturator to return it along the arcuate path into sealing contact with the packing 22. The peripheral wall of the sleeve 21 is rounded as shown to enable the sleeve to automatically take up the best sealing position with the obturator.</p> |
