| 摘要 |
963,809. Valves. CRANE Ltd. Jan. 2, 1963 [May 23, 1962], No. 257/63. Heading F2V. The rotatable stem of a valve is connected to the hub 5, Fig. 1, of a crank 4, the outer end of which houses a rotatable nut 7 receiving a threaded shaft 9 passing through a trunnion 13 and prevented from axial movement by thrust collars 26, 27. The outer end of the shaft 9 is provided with a hand wheel 32 or a gear driven by an electric or hydraulic actuator. The crank and threaded shaft are housed in a casing 1, one side of which is closable by a cover 10, Fig. 2. The trunnion 13, which is square or polygonal, has stub journals 14, 15 and a distortable dust seal 21, Fig. 1, at each side thereof; the seal consists of two oppositely disposed tubes 22, 23, Fig. 2, of natural or synthetic rubber which are slightly compressed when the cover 10 is in position. The outer surfaces of the tubes are housed in recesses in the easing 1, Fig. 1, around the opening 3 therein for the shaft 9. Sealing is effected by both the longitudinal and end surfaces of the tubes. When the shaft 9 is rotated the crank 4 is swung through 90 degrees and the trunnion 13 is consequently rocked through about 15 degrees, causing distortion of the seal. |
