Abstract

A dumbbell including a bar having at each end a plurality of longitudinal grooves, of different lengths, closed at their inner ends and opening at their outer ends into a cross groove. The cross groove is defined on its outer edge by a rib at the end edge of the bar. An inlet groove opens through the end of the bar, and lets into the adjacent longitudinal groove. An inner collar slides on the bar, having a dowel pin riding in the grooves and positionable in a selected groove to accommodate a corresponding number of weights. A square headed bolt threads into the end of the bar, and the locking collar has a square hole enabling it to be slid over the bolt head, and a square socket coincident with the hole, receiving the bolt head upon turning the collar 45°, and the collar can then rotate the bolt. Another form includes a locking collar having a keyhole slot to enable the collar to be removed over the bolt head that normally holds it in place, and in still another form, the locking collar has a radial slot opening through its periphery, to enable the collar to be removed without removing the bolt.