Patent ID: 7413533

Claim:
An adjustable dumbbell comprising: a shaft including two opposite connecting ends, an intermediate portion between said connecting ends, and left- and right-handed threads that are formed on said intermediate portion and that are axially spaced apart from each other; two tubes sleeved around and engaging threadedly and respectively said left- and right-handed threads; a hollow grip rod sleeved on said tubes and having two opposite engaging portions; two support units each having upper and lower support seats disposed above and below one of said tubes, said upper and lower support seats including inner end faces respectively connected to said engaging portions, outer end faces opposite to said inner end faces, and intermediate sections each interconnecting one of said inner end faces and one of said outer end faces and each provided with a plurality of spaced-apart spacers; two sets of weights, said weights in each set straddling said upper and lower support seats of one of said support units and being spaced apart from each other by said spacers, each of said weights including a straddling hole that has an engaging hole section engageable with a corresponding one of said tubes; and two adjustment knob units respectively connected to said connecting ends of said shaft to turn said shaft relative to said grip rod and to thereby move said tubes axially of said shaft in opposite directions towards or away from said connecting ends; each of said tubes being movable between said upper and lower support seats of one of said support units to selectively engage one or more of said engaging hole sections of said weights.