| 摘要 |
A resilient element such as a thin flat plate or disc spring, commonly known as a "Belleville" spring, which is capable of deflection along an axis normal to its surface is modified to include an amplifying segment disposed in a central aperture in the form of an approximately "W" shaped strip corrected at its ends to opposite positions on the inner margin of the central opening. The central portion of the "W" forms an inverted "U" which is subjected, after positioning within the central aperture, to torquing stress in the plane of the material to bring the ends of the open end of the "U" slightly closer together than the inner edges of the "U" nearest its closed end. One of a pair of Switch contacts is mounted on the closed end of the "U" shaped portion of the device opposite another contact carried on the switch base. Means are provided for applying pressure, normal to the plane of the material, on some position of the peripheral sensing spring in which the ends of the "W" shaped portion connect with the inner margin of thecentral opening of said sensing spring and when such pressure rises to a predetermined level, the "U" shaped portion will snap over to a position in which the contact which it carries will assume an opposite portion with respect to the contact carried by the switch frame.
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