| 摘要 |
A float switch for sensing a liquid level and switching between "on" and "off" states in response to the same. Overall, the device is carried within a hollow housing, with its movement restrained by the tethering action of a power cord. "Snap action" switching is achieved by the interaction between an actuator having camming surfaces formed on its exterior, and a spring-loaded switch mechanism. The switch mechanism includes a thin, flexible E-shaped snap member, having two legs bowed to form a leaf spring and having a bearing point located on the central leg. The actuator is carried in a tube within the housing and the switch mechanism is positioned adjacent the actuator's path of travel, so that a camming surface of the actuator can make contact with the bearing point. As the water level rises, an increasing proportion of the actuator's weight is carried by the bearing point, until the vertical component of the actuator weight exceeds the spring resistance of the snap member. The characteristic operation of the spring is such that it yields only suddenly and completely rather than gradually, providing a desirable snap action operation.
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