Switch assembly

A submersible switch assembly for starting and stopping a pump that is operable to remove liquid intermittently upon demand from a chamber comprising a mounting bracket, a hermetically sealed float pivotally mounted on said bracket for pivotal movement between an upper and a lower position, said float containing an electrical switch with a trip arm for closing and opening the switch, a raceway extending generally in a radial direction relative to the axis of pivotal movement of the float and located adjacent to said electrical switch and into which said trip arm extends, said raceway having an intermediate portion and radially inner and outer end portions, said radially inner and outer end portions having positive slopes toward said intermediate portion at all times during pivotal movement of said float except when said float is pivoted essentially to its upper or lower positions, the radially inner end portion having a negative slope toward the intermediate portion only when said float is pivoted essentially to its lowermost position and the radially outer end portion having a negative slope toward the intermediate portion only when said float is pivoted essentially to its uppermost position, and a roller element movable in response to gravity the length of said raceway, said roller element being operable when said float is pivoted to its lower position to roll from the radially inner end of said raceway over said intermediate portion to the radially outer end and operable when said float is pivoted to its upper position to roll from said radially outer end over said intermediate portion to said radially inner end, said trip arm extending into said raceway so as to be actuated by said roller element during traverse of said raceway, said trip arm entering said raceway at a location adjacent to the inner end of the radially inner end portion and extending to a location adjacent to said intermediate portion so that maximum mechanical advantage for closing said switch occurs when the roller element passes radially inwardly over the extended end of the trip arm.