US Patent 6983950 Quick change hitch ball assembly

A hitch ball assembly includes a towing ball having a mounting aperture and an annular race in communication with the mounting aperture. A post includes a base, an axial bore and a plurality of openings in communication with the axial bore. A ball bearing is received in each of these openings. A plunger is axially displaceable in the post between a first position allowing the towing ball to be removed from or attached to the post and a second position for securing the towing ball to the post while allowing the towing ball to turn on the post. A spring, received in the axial bore, engages an end of the plunger and biases the plunger to the first position.