| 摘要 |
1491631 Pneumatic actuation of switches STOP ALERT CORP 6 Feb 1975 [8 Feb 1974] 5047/75 Heading H1N A fluid pressure responsive electric switch assembly which may be used, for example, in parallel with the usual brake fluid operated switch to energize stop lights by manifold vacuum when the foot is removed from the accelerator prior to depression of the brake pedal, comprises first and second chambers 1 and 61 separated by a nipple 11, a diaphragm 67 dividing said second chamber into two sections 63 and 65 and biased to close said nipple 11, a switch 21, a movable switch operating member 51 in said first chamber, biased in one direction of its movement, whereby upon establishment of a pressure difference between said sections 63 and 65 beyond a predetermined threshold and in a predetermined sense said diaphragm 67 moves to open said nipple 11 allowing said pressure difference to move said member 51 against its bias to operate the switch 21, the assembly further comprising means 71 for adjusting said threshold and means 69 for automatically allowing a gradual decay of said pressure difference and thereby the delayed return of member 51. As shown section 65 has a threaded fluid coupling 71 which also serves to adjust the threshold at which the diaphragm 67 opens nipple 11 by setting the bias provided by a spring 75. The switch operating member 51 is a ball biased by gravity to depress arm 17 and normally hold contact 47 away from rigid contact 39. A pad 93 of felt or rubber absorbs the impact of ball 51 when it is lifted by vacuum created in section 63 by the lifting of diaphragm 67 by vacuum in section 65. A leak hole 69 in the diaphragm 67 allows decay of the pressure differential across the diaphragm, and a pad 55 filters atmospheric air entering by slot 53. |
