Non-metallic sprocket chain having quick detachable, twist-locking pivot pins

Claim 1

A sprocket chain which includes a plurality of identical, longitudinally adjoining links pivotally connected to one another by quickly detachable pivot pins, wherein: (a) each link comprises an integral, generally elongated, U-shaped body of synthetic resin composition formed with a pair of longitudinally extending side arms terminating at one end thereof in transversely spaced apart, but relatively aligned eye portions and connected at their opposite ends by an integral, tubular cylindrical yoke portion having a pivot pin-receiving bore extending therethrough, said eye portions being normally spaced apart a distance greater than the width of the yoke portion of said links and being resiliently flexible inwardly toward one another, each eye portion having a cylindrical pin-receiving bore extending therethrough and one eye portion of each of said links having an arcuate cam formed with an axially inclined bearing surface extending from the inner wall of its pin receiving bore and including a pin-locking recess; and wherein (b) each of said pivot pins comprises an elongated generally cylindrical body portion of synthetic resin composition formed at one end thereof with a radially enlarged head and at its opposite end with a diametrically reduced, cylindrical terminal having a cam follower locking lug projecting radially outwardly therefrom, but terminating radially inwardly with respect to the cylindrical outer surface of the body portion of the pin, the cylindrical body portion of each pin being sized to closely but rotatively pass through the bores of the eye portions of one link and the bore of the yoke portion of an adjoining link to pivotally join said links, and the cam follower locking lug of each pin being disposed, upon full insertion and axial rotation of the pin in the eye portions of a link, to initially engage with the cam bearing surface of said link and to resiliently flex the eye portions of the link toward one another before reaching the pin-locking recess of said cam bearing surface, said cam follower locking lug, upon reaching said recess, permitting the eye portion of said link to resiliently snap outwardly to a position in which said locking lug is retained in said recess.