Abstract: The present invention provides an assembly for attaching a hub to a shaft. The hub, which may be a portion of a gear, pulley, chain sprocket or other power carrying device, includes a collar or annular wall having two axially extending relief cuts on opposite sides of a shaft opening, which define a pair of opposed projections or clamp members. The clamp members include opposed flats on the inside of the shaft opening which engage complementarily configured flats on the shaft. A threaded fastener such as a bolt extends through smooth radial bores in one clamp member and the shaft and into a complementarily threaded bore in the other clamp member. The internal flats of the hub include opposed arcuate, axially extending reliefs. The outside surface of the hub proximate the smooth bore defines a chordal surface which the bolt engages.

Abstract: The present invention provides an assembly for attaching a hub to a shaft. The hub, which may be a portion of a gear, pulley, chain sprocket or other power carrying device, includes a collar or annular wall having two axially extending relief cuts on opposite sides of a shaft opening, which define a pair of opposed projections or clamp members. The clamp members include opposed flats on the inside of the shaft opening which engage complementarily configured flats on the shaft. A threaded fastener such as a bolt extends through smooth radial bores in one clamp member and the shaft and into a complementarily threaded bore in the other clamp member. The internal flats of the hub include opposed arcuate, axially extending reliefs. The outside surface of the hub proximate the smooth bore defines a chordal surface which the bolt engages.