GB1250722A - - Google Patents

Abstract

1,250,722. Valves; toggle mechanisms. KING OF PRUSSIA RESEARCH & DEVELOPMENT CORP. 5 March, 1970, No. 10552/70. Headings F2K and F2V. The operating member or stem 23 of a valve is movable normally between closed and open positions by power means such as an electric motor (87), Fig. 1 (not shown), and on failure of the power means a compressed spring 30 is released to move the stem to a fail-safe position. The spring is compressed through a carriage 50 carrying ball detents 33 which are normally locked into a stationary groove 36 by a retaining member 38. This retaining member is coupled to a latch mechanism 62, Fig. 6, which releases on power failure. As disclosed, the stem is threadedly engaged by a splined sleeve 24 driven by the motor through worm gearing 20, 21. The sleeve is mounted by thrust bearings in the carrier 50. Retaining member 38 is coupled through a lever 43 and shaft 44 to a latching device including a two-part latching arm 74, 75 with a Belleville spring stack 55. The latching device, Figs. 6 to 8 (not shown), comprises a toggle mechanism consisting of an arm (63) carrying a pawl (75) and mounted on a fixed pivot (65). A floating lever (68) is pivoted both to the arm (63) at (69) and at (70) to a triangular lever (68) mounted on a fixed pivot (66). The triangular lever is pivotally connected at (83) to a return spring link (81) and the floating lever (68) to a solenoid (60). On deenergization of the solenoid the toggle is broken by the spring link and the latch disengaged. To prevent shock at the end of the release stroke when the valve is arrested by an abutment, a restrictor valve 97 is closed by the rising stem 23 to throttle a flow of oil out of the sleeve 24. A cam bar 49 on the carriage 50, through follower 52 and shaft 81, operates switches (110), Fig. 5 (not shown), for position indicating purposes.