Hub structure for rotary finishing wheels

A hub structure for a rotary finishing wheel having a rotational axis and being adapted for replaceably mounting a plurality of circumferentially spaced pack units each of which includes a flap-like member of fill material having a radially outer finishing portion for engaging a workpiece and a radially inner slot-engaging portion for mounting said pack unit, said hub structure comprising two substantially identical hub sections generally representing the two halves of a longitudinally bisected cylinder, the radially outer surface of each of said hub portions having a generally semi-circular exterior contour provided with a plurality of integrally-formed, circumferentially-spaced, quasi-cylindrical, key-hole-type, slot-forming means each having a longitudinal slot axis parallel to said rotational axis, each of the longitudinal slots defined by said slot-forming means being adapted to slideably and telescopically receive the slot-engaging portion of said flap-like member to mount the pack unit for limited hinge-type pivotal movement about said slot axis, the interior of each of said hub portions including an integrally-formed, centrally-disposed, radially inwardly extending member having its inner end adapted to form a clamp seat having the general contour of the shaft to which said hub structure is to be secured, said member being generally normal to the plane of bisection of said hub portions, the interior of each of said hub portions further including a pair of flange portions generally parallel to said plane of bisection and integral with the longitudinally bisected edge portions of the hub portion, said flange portions extending radially inwardly toward one another and each having its radially inner end adapted to form one half of another shaft-engaging seat, said hub structure further including means for adjustably securing each of said pair of flange portions of one hub portion to corresponding opposed flange portions of the other hub portion to form a pair of oppositely disposed shaft-engaging seats from said flange portions while securely clamping said shaft between the clamp seats of the oppositely disposed members of the two hub portions to secure said hub structure to said shaft for rotation therewith and means for removeably retaining the slot-engaging means of said flap-like members axially within said longitudinal slots.