Flow controlled switch, operated by a pivotal shaft

Claim 1

Mechanism for detecting flow in a fluid carrying conduit having an aperture therein, said mechanism comprising: a housing adapted for securement to the conduit in overlying, sealing relationship to said aperture and having an opening in a side of the housing; a switch disposed exteriorly of said side of the housing for indicating flow through the conduit when actuated; flow detecting means adapted for insertion in the conduit and shiftable in response to fluid flow therethrough, said flow detecting means extending into said housing and including a shaft extending exteriorly of the housing through said opening therein with an outer portion of said shaft located in engaging relationship with said switch to actuate the latter; a resilient member at said side of the housing closing said opening and sealingly engaging said shaft, said member having a pair of aligned, elongated grooves spaced apart on opposite sides of said shaft; a rigid backup element secured to said housing and overlying said resilient member to hold the latter in sealing relationship in said opening against hydraulic pressure developed within said housing; and an arm located within the housing and secured to said shaft, said arm includIng a pair of projections disposed on opposite sides of said shaft and spaced therefrom, said projections having knife edges movably received within said grooves and in a close fitting relationship therewith resulting in corresponding low friction pivotal movement of said arm relative to said backup element, said projections further cooperating with said resilient member to allow limited pivotal movement of said shaft about said knife edges to actuate said switch while resisting movement of said shaft other than said pivotal movement thereof upon shifting of said flow detecting means in response to flow in the conduit.