US Patent 7172536 Adjustable dumbbell

An adjustable dumbbell includes a number of weights each having a slot to receive end portions of a bar, and a number of latch rods slidably engaged in the weights and each having an inner end engageable into the slots of the weights and engageable with the bar, to anchor and latch a selected number of the weights to the bar, and to allow the selected weights to be moved in concert with the bar. The weights each has a spring member to bias and force the inner end of the latch rod to engage with and to latch the weights to the bar. The weights each includes a panel having an orifice to slidably receive the latch rod, and to anchor the latch rod to the panel when the catch of the knob is rotated relative to the panel.