| 摘要 |
A precision subminiature, snap action switch and an externally actuated, heavy duty, spring loaded self-return type operator therefor are enclosed within an hermetically sealed housing. The operator employs a switch actuating cam having shoulders cooperable with shoulders on the interior of the housing to define the limits of cam movement, said cam also having a shoulder cooperable with a shoulder on a switch lever to trip the switch upon movement of the externally actuated operator shaft a precise amount away from its at rest position. A connector/switch subassembly sealingly closes a housing opening, provides a rigid, precision mounting for the switch, and also provides external electrical connections for the switch. The operator has an externally projecting shaft which extends through a shaft bearing/rotary seal assembly employing a silicone rubber O-ring member and oil for lubricating a shaft bearing and the O-ring member, there being additional polytetrafluoroethylene O-ring members which prevent escape of the lubricating oil. An end cap sealingly closes another housing opening, provides a bearing for the inner end of the operator shaft, and exerts a predetermined stress on the operator spring. The structure lends itself to a simplified fabrication method.
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