Mechanically actuated vent switch

Claim 1

A mechanical idle vent valve assembly comprising: a housing having a first passage in communication with a float bowl primary fuel chamber, said housing including a second passage adapted to be communicated with an inlet to a charcoal cannister, means forming a valve seat interposed between said first and second passages, a reciprocating shaft having a square cross section directed through said housing, said square shaft adapted to be connected to an accelerator plunger assembly within a float bowl of a carburetor, means on said housing for supporting said square shaft for reciprocation with respect to said housing and against rotation with respect thereto, said square shaft having a threaded extension thereon, a stem adaptor having an internally threaded open ended portion thereon with a radially outwardly directed end flange threadably received on the threaded extension of said squared shaft for axial adjustment thereon, said stem adaptor including a circumferential groove formed thereon on the opposite end of said threaded portion from the flange end thereon, a spring retainer slidably supported within said groove, a valve element slidably supported on the outer surface of said stem adaptor at the opposite end thereof having a surface thereon supportingly received By said radially outwardly directed flange, a spring having one end thereof in engagement with said retainer and the opposite end in engagement with said valve for biasing said valve against said flange, said adaptor including an end portion thereof defining a bearing surface, an operating lever having a first portion thereon engageable with said bearing surface, means for pivotally supporting said lever for rotation with respect to said housing, said lever having a second portion thereon adapted to be connected to a throttle link for moving said first portion with respect to said bearing surface to cause said stem adaptor and said squared shaft to reciprocate with respect to said housing, said lever having a first operative position when the throttle is open to locate said valve element against said valve seat, said spring biasing said valve against said valve seat when said lever is in its first position to close communication between said first and second passages to prevent vapor transfer from the primary fuel chamber to the cannister when the throttle is open, said lever having a second operative position when the throttle is closed to position said vent valve in spaced relationship to said seat to communicate said first passage with said second passage thereby to direct vapor from the primary fuel chamber to the cannister, said lever having a third operative position wherein said stem adaptor and squared shaft are directed inwardly of the housing when the vent valve is closed to operate said plunger assembly with said vent valve being maintained sealed against said seat by said spring as said stem adaptor and squared shaft are moved axially relative thereto, said spring and said vent valve coacting to permit free sliding movement of said stem adaptor with respect to said seated vent valve to maintain said plunger assembly operative independently of the relative relationship between said vent valve and said valve seat and said vent valve being positioned independently of operation of said plunger assembly.