Air valve carburetor

Claim 2

A carburetor comprising a mixture conduit having an air inlet and a mixture outlet, a throttle disposed in said outlet for controlling flow therethrough, an air valve disposed in said air inlet and movable between closed and open positions, means biasing said air valve toward said closed position, a diaphragm connected to said air valve for moving said air valve toward said open position against the bias of said biasing means, one side of said diaphragm being exposed to the pressure in said air inlet upstream of said air valve, and means associated with the other side of said diaphragm for defining therewith an enclosed chamber connected to said mixture conduit between said air valve and said throttle, whereby said diaphragm and said biasing means are effective to position said air valve to establish a selected pressure differential thereacross, and wherein said diaphragm has an opening extending therethrough to permit air to flow continuously from said air inlet upstream of said air valve through said opening and said chamber to said mixture conduit downstream of said air valve to thereby purge fuel from said chamber and inhibit accumulation of fuel in said chamber and a plate overlying said opening and having a calibrated hole restricting air flow through said opening to control the rate thereof.

Claim 3

A carburetor comprising a mixture conduit having an air inlet and a mixture outlet, a throttle disposed in said outlet for controlling flow therethrough, an air valve disposed in said air inlet and movable between closed and open positions, a spring biasing said air valve toward said closed position, a diaphragm having a link extending to said air valve for moving said air valve toward said open position against the bias of said spring, one side of said diaphragm being exposed to the pressure in said air inlet upstream of said air valve, a cover associated with the opposite side of said diaphragm to define an enclosed chamber therebetween, means defining a passage connecting said chamber to said mixture conduit between said air valve and said throttle, whereby said diaphragm and said spring are effective to position said air valve to establish a selected pressure differential thereacross, a backing plate secured on one side of said diaphragm and defining a recess therebetween, said diaphragm having a hole opening to said recess, and said backing plate having a calibrated hole opening to said recess whereby air may flow from said air inlet upstream of said air valve through said diaphragm, said recess, said backing plate, said chamber and said passage to said mixture conduit downstream of said air valve at a rate determined by the size of said calibrated hole to thereby purge fuel from said chamber and inhibit accumulation of fuel in said chamber.

Claim 4

A carburetor comprising a mixture conduit having an air inlet and a mixture outlet, a throttle disposed in said outlet for controlling flow therethrough, an air valve disposed in said air inlet and movable between closed and open positions, a spring biasing said air valve toward said closed position, a diaphragm having a link extending to said air valve for moving said air valve toward said open position against the bias of said spring, one side of said diaphragm being exposed to the pressure in said air inlet upstream of said air valve, a cover associated with the opposite side of said diaphragm to define an enclosed chamber therebetween, means defining a passage connecting said chamber to said mixture conduit between said air valve and said throttle, whereby said diaphragm and said spring are effective to position said air valve to establish a selected pressure differential thereacross, a backing plate secured on one side of said diaphragm and defining a recess therebetween, said diaphragm having a hole opening to said recess, and said backing plate having a calibrated hole opening to said recess whereby air may flow from said air inlet upstream of said air valve through said diaphragm, said recess, said backing plate, said chamber and said passage to said mixture conduit downstream of said air valve at a rate determined by the size of said calibrated hole to thereby purge fuel from said chamber and inhibit accumulation of fuel in said chamber.

Claim 5

A carburetor comprising a mixture conduit having an air inlet and a mixture outlet, a throttle disposed in said outlet for controlling flow therethrough, an air valve disposed in said air inlet and movable between closed and open positions, a spring biasing said air valve toward said closed position, a diaphragm having a link extending to said air valve for moving said air valve toward said open position against the bias of said spring, one side of said diaphragm being exposed to the pressure in said air inlet upstream of said air valve, a cover associated with the opposite side of said diaphragm to define an enclosed chamber therebetween, means defining a passage connecting said chamber to said mixture conduit between said air valve and said throttle, whereby said diaphragm and said spring are effective to position said air valve to establish a selected pressure differential thereacross, a first backing plate secured on said one side of said diaphragm and defining a first annular recess therebetween, a second backing plate identical to said first backing plate secured on said opposite side of said diaphragm and defining a second annular recess therebetween, said first backing plate having a calibrated opening extending from said air inlet upstream of said air valve to said first recess, said diaphragm having an opening extending between said recesses, and said second backing plate having a calibrated opening extending from said second recess to said chamber, whereby air may flow from said air inlet upstream of said air valve through said first backing plate and recess, said diaphragm, said second recess and backing plate, and said chamber and passage to said mixture conduit below said air valve at a rate determined by the size of said calibrated openings to purge fuel from said chamber and to inhibit accumulation of fuel in said chamber.

Claim 6

A carburetor comprising a mixture conduit having an air inlet and a mixture outlet, a throttle disposed in said outlet for controlling flow therethrough, an air valve disposed in said air inlet and movable between closed and open positions, a spring biasing said air valve toward said closed position, a diaphragm having a link extending to said air valve for moving said air valve toward said open position against the bias of said spring, one side of said diaphragm being exposed to the pressure in said air inlet upstream of said air valve, a cover associated with the opposite side of said diaphragm to define an enclosed chamber therebetween, means defining a passage connecting said chamber to said mixture conduit between said air valve and said throttle, whereby said diaphragm and said spring are effective to position said air valve to establish a selected pressure differential thereacross, a first backing plate secured on said one side of said diaphragm and defining a first annular recess therebetween, a second backing plate identical to said first backing plate secured on said opposite side of said diaphragm and defining a second annular recess therebetween, said first backing plate having a calibrated opening extending from said air inlet upstream of said air valve to said first recess, said diaphragm having an opening extending between said recesses, and said second backing plate having a calibrated opening extending from said second recess to said chamber, whereby air may flow from said air inlet upstream of said air valve through said first backing plate and recess, said diaphragm, said second recess and backing plate, and said chamber and passage to said mixture conduit below said air valve at a rate determined by the size of said calibrated openings to purge fuel from said chamber and to inhibit accumulation of fuel in said chamber.