Vehicle speed-limiting apparatus

Claim 1

A governing apparatus for a double barrel compound type carburetor having primary and secondary induction passages, throttle valve in each of said passages and a mechanism for opening the primary throttle valve, comprising servo means for controlling the secondary throttle valve in accordance with venturi vacuum force produced at least within said primary induction passage and a vacuum source communicated therein, said servo means including a casing, a first and second diaphragm members clamped within said casing for forming a first, second and third chambers, said third chamber being normally connected to said vacuum source, a link device connected to said first diaphragm member for controlling opening degree of said secondary throttle valve and a first and second springs respectively installed within said second and third chambers to normally bias said link device to urge said secondary throttle valve in a closing direction, said first spring having a larger biasing force than that of said second spring; first conduit means for connecting said first chamber constantly with the atmosphere; second conduit means for bleeding said second chamber into a venturi in said primary induction passage; means for selectively connecting said third chamber to the atmosphere when vehicle speed exceeds a predetermined value; and a vehicle speed responsive governor for regulating Said means.