US Patent 7137932 Dumbbell adjusting system

A dumbbell adjusting system comprises an adjusting system, a stand, and a locking mechanism. The adjusting system includes two rods on the dumbbell's handle which move in and out of the handle to selectively engage the inner threaded through holes of the weights. The weights are configured to interlock with one another so as not to move independently. The locking mechanism unlocks the weights from the handle when the dumbbell is in the stand, allowing the user to select the desired weight, and locks the weights into the handle when the dumbbell is lifted out of the stand.