| 摘要 |
<p>1464637 Fluid-pressure switches EUROPE MFG TRUST REG 9 Oct 1974 [10 Oct 1973 8 April 1974] 43705/74 Heading H1N In a fluid-pressure diaphragm operated switch, a snap-acting blade 36, Fig. 1, carrying a double contact 37 movable between a pair of stationary contacts 38, 39 has an integral tongue 40, Fig. 3, extending within an aperture 43 in the blade for engagement by the diaphragm actuator 31 and has an over centre spring 41 extending between the ends of the blade 36 and tongue 40 to maintain the contact 37 in firm engagement prior to the point of snap over. Apertures 43 and 48 are provided in the blade 36 and tongue 40 to increase the resilience and absorb impact forces occurring on contact closure. The diaphragm 18 is clamped between a pair of housing members 12, 14 and carries a rigid plate 30 supporting a domed actuator 31 carrying a slidable pin 60 in a recess for engagement with the contact tongue 40. The pin 60 forms part of a spring loaded plunger 59 supported by adjustable compression springs 75, 76 which are preset according to the required pressure settings and operating differentials. Spring 75 acts constantly on the plunger 59 while spring 76 engages stops 69 on the casing so that it is inoperative at lower pressures. The pressure inlet 22 for the diaphragm has an orifice 26 with a length determined by a bore 27 and operates to damp out transient pressure changes as in applications to domestic dishwashers and washing machines.</p> |
