Centrifugal-type injection timing adjusting device for internal combustion engines

Claim 1

A centrifugal-type injection advance device for an internal combustion engine comprising: first and second opposed casing members rotatable about an axis and adapted to be connected, respectively, to a driving shaft and a driven shaft; a set of flange pins mounted in the first casing member and extending towards the second casing member, each flange pin having a curved surface of a first radius; a set of flyweights and a pivoting stud connecting each flyweight to said second casing member for pivoting movement of the flyweight about an axis parallel to the said axis; a curved cam surface formed on each flyweight facing its respective pivoting stud, each of said flange pins positioned with its respective curved surface adjacent the cam surface of one of said flyweights; a spring mounted on each flyweight to urge its respective flange pin against its respective cam surface; said flyweights having a curved face formed therein opposing the said cam surface, and each said flange pin including an axial protrusion having a cylindrical surface portion extending axially towards the second casing member and positioned adjacent the said curved face and in sliding contact therewith, said cylindrical surface portion of the protrusion having a second radius less than the first radius, whereby the space between the cam surface and the curved face of each flyweight permits the flyweight to move arcuately outwardly relative to said flange pin while concurrently preventing movement of the flange pin towards the pivot axis of its respective flyweight.