| 摘要 |
1,199,431. Valves. E.B.V. SYSTEMS Inc. 4 Aug., 1967 [8 Aug., 1966], No. 35866/67. Heading F2V. A mechanism for operating a rotary valve (24, Fig. 1, not shown) having an operating stem 32, comprises a drum 42 which is rotatable by a constant torque spring 90 in one direction to effect closing of the valve, and is rotatable in the opposite direction by a motor-driven gear unit 36 to effect opening of the valve, the drum being releasably holdable in a position corresponding to the open state of the valve and being arranged to act on the valve stem through a lost-motion coupling. Upon the de-energization of a solenoid (142, Figs. 1 and 2, not shown), as by opening a switch or due to power failure, a latch arm 130, carrying at its free end a roll 132, is caused to move into the plane of the drawing, as seen in Fig. 5, thereby moving roll 132 out of engagement with an abutment 144 provided on a gate member 106 pivoted at 120. The gate member is therefore caused, by a spring 152, to rotate in the clockwise direction, to the dotted line position shown, so permitting a roll 102, provided on a latch lever 100 which is pivoted at 94 to the drum, to move out of a notch 104 formed on the gate member, this serving to release the drum which is then free to rotate in the clockwise direction. Such rotation causes one pair of opposed lugs 80, provided on the drum, to engage, after a predetermined angle of rotation, two lugs 76 depending downwardly from a member secured to the valve stem, the degree of rotation being limited by a fixed stopmember 62. To reset the valve, the solenoid is re-energized, and power is supplied to a motor unit (188, Fig. 1), which unit drives the gear 36 in a counterclockwise direction. A cam roll 184 on the gear, engages a cam surface 182 on the gate so bring- ing it back to its normal position, shown in full lines. Simultaneously the latch arm 130 is moved upwardly to engage and thereby retain the gate in this position. Further rotation of the gear serves to rotate the drum counterclockwise, this being effected by engagement of a lug 176 on to gear with a roll 170 on the latch lever, until the valve is opened, at which stage the roll 102, which has been moving along an arcuate surface 224 on the gate 106, drops into the notch 104 and so serves to hold the drum in its original position. Disposed on the uppermost end of the valve stem in a cam (192, Fig. 1), which carries a circumferential series of lobes adapted to successively actuate three microswitches 194, 196 and 198, and hence three corresponding warning lights, these lights giving indication as to whether the valve is fully open, not closed, or fully closed. In an alternative embodiment (Figs. 7 to 10, not shown), the mechanism is modified to permit resetting of the valve in two separate steps, first recocking of the drum and then returning the valve to open position.
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