Chain drive

In a chain drive including an endless drag conveyor chain formed of interconnected links, each link having a fork constituted by parallel-extending fork legs including a base portion, shoulder faces disposed at the base portion and fork leg ends remote from the base portion;

• a drive sprocket and a return sprocket about which the chain is trained;
• each sprocket having an axis of rotation, first and second series of teeth arranged circumferentially on the periphery of each sprocket, the first series of teeth and the second series of teeth defining an axial space therebetween;
• each tooth having a leading flank and a trailing flank, each tooth having a circumferentially measured thickness that is smaller than the distance from the shoulder faces to the fork ends of the adjoining link;
• each sprocket further having a polygon disposed in the space between the first and the second series of teeth;
• the polygon having axially parallel edges separating the polygon sides from one another, the polygon having peripheral support faces for radially supporting the links in their passage on the sprockets, the improvement wherein each said peripheral support face of said polygon is formed of a narrow support area at both sides of each said edge of the polygon, each said area defining a plane parallel to the sprocket axis and extending between said tooth series in said axial space and being substantially out of registry with any of said teeth when viewed circumferentially;
• each said support area further being, when viewed in the axial direction, substantially in its entirety out of registry with any of said teeth for providing a radial support for said links adjacent said teeth when viewed circumferentially;
• said support areas of said polygon constituting the sole radial support of said links in said sprockets;
• said links being substantially without radial support at any location in circumferential alignment or in axial alignment with any of said teeth.