Patent ID: 7429235

Claim:
A dumbbell comprising: a hollow grip bar having a connecting end; a weight adjusting mechanism disposed at each end of the hollow grip bar and including a screw rod extending into said grip bar, and operable to rotate relative to said grip bar about a rotation axis, and a weight carrier extending into said grip bar and engaging threadedly said screw rod so as to be movable axially upon rotation of said screw rod about said rotation axis, said weight carrier having at least a portion thereof capable of extending outwardly through said connecting end of said grip bar; a rotatable knob at the connecting end of the dumbbell, said rotatable knob being operatively connected with the screw rod such that rotation of the rotatable knob causes rotation of the screw rod which, in turn, generates linear motion of the weight carrier within the receiving portion of the weights as a result of the threaded engagement between the screw rod and the weight carrier; and a plurality of weights, each of said plurality of weights comprising an elongate notch having a receiving portion for receiving said weight carrier therethrough; and wherein there is no threaded engagement between the weight carrier and the weights during movement of the weight carrier through the receiving portion, wherein said weight carrier comprises a tubular member sleeved on said screw rod and formed with an inner thread that threadedly engages said screw rod, and wherein said weight adjusting mechanism further includes a limiting member secured to said connecting end of said grip bar, disposed outwardly of said grip bar, defining an axially extending central channel for extension of a weight supporting part of said weight carrier thereinto, and formed with an inner limiting groove extending axially and in spatial communication with said central channel, said weight-supporting part of said weight carrier being formed with a limiting protrusion that extends into said inner limiting groove in said limiting member so as to prevent rotation of said weight carrier upon rotation of said screw rod about said rotation axis.