| 摘要 |
1,166,947. Valves; screw and nut gearing. ACF INDUSTRIES Inc. 2 March, 1967 [1 July, 1966], No. 9881/67. Headings F2Q and F2V. A gate valve has a non-rotatable rising spindle 46 reciprocated by a nut 62 rigidly connected to a gear 64, and driven by a hand-wheel 67, or an electric or hydraulic motor, and comprises a stop member 84 having screw threads of finer and opposite pitch than those of the nut 62, which co-operate with similar threads cut into the crests of the spindle threads, so that when the spindle reaches e.g. a lower limiting position, the stop is rotated to bind on to the upper surface 92 of the nut 62. The stop is locked in position on the spindle 46, by a pin 88 (90), Fig. 4 (not shown), which is slipped between the flanks of the spindle thread. The stop may be locked in position by a set screw (104), Fig. 5 (not shown). |
