| 摘要 |
A snap disc operator pressure switch is disclosed in which a thin flexible diaphragm is positioned adjacent to the disc to isolate the pressure chamber from the disc chamber and to transmit the pressure forces directly to the surface of the disc. The disc is positioned in a disc seat and is held therein by the diaphragm. The calibration of the disc is not adversely affected because it is not necessary to provide a seal directly with the disc. The disc seat member is shaped to support the disc against overpressure and to provide a guide for the switch bumper. When higher operating pressures are required, two discs are positioned in the disc seat at face-to-face adjacency and the device operates at a pressure substantially equal to the sum of the calibration pressures of the discs. In another embodiment, the movable arm of the switch is biased closed and is moved to an open position by a spring-biased operator. In such embodiment, the maximum stress applied to the movable arm is determined by the spring force on the operator, so overstressing and fatigue failures of the arm are substantially eliminated.
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