Patent ID: 7491157

Claim:
A weight-adjustable dumbbell comprising: a dumbbell shell unit including a hollow shell body confining a receiving space, and having a top shell portion with an inner side that faces said receiving space, and an outer side opposite to said inner side, said shell body further having an open bottom shell portion opposite to said top shell portion in a vertical direction, a weight selector rod having a top rod end connected to said top shell portion, extending downwardly from said inner side of said top shell portion into said receiving space of said shell body, and formed with a plurality of through holes spaced apart from each other in the vertical direction, said shell body being formed with a plurality of insert holes, each of which is registered with a respective one of said through holes in said weight selector rod, and a handle connected to said outer side of said top shell portion; a weight unit extended removably into said receiving space via said bottom shell portion of said shell body, said weight unit including a base member provided with a pair of upwardly extending positioning posts, and a plurality of weight pieces stacked on said base member, each of said weight pieces having top and bottom sides, a rod hole formed through said top and bottom sides for extension of said weight selector rod, and a pair of post holes formed through said top and bottom sides for extension of said positioning posts, respectively, said bottom side of each of said weight pieces being formed with a first slot registered with a corresponding one of said through holes in said weight selector rod and a corresponding one of said insert holes in said shell body; and an insert pin unit including an insert pin inserted removably into a selected one of said insert holes in said shell body, extending along said first slot in said bottom side of one of said weight pieces corresponding to the selected one of said insert holes, and extending removably through one of said through holes in said weight selector rod corresponding to the selected one of said insert holes such that, when said dumbbell shell unit is lifted relative to said base member, said one of said weight pieces is moved together with any other of said weight pieces disposed thereabove and said shell body away from said base member.