bracelet, arm-band, small bell
鐲 centers on a metal ring worn on the body: a bracelet or arm-band. The small bell sense is a related metal object that rings, but the core idea is a circular metal adornment.
鐲 combines 金 (metal) with 蜀, which likely contributes the sound. The character originally referred to a metal bell or bracelet.
The left side 金 (metal) and the right side 蜀 (which looks like a wrapped insect) together suggest a metal ring encircling the arm like a coiled bug: a bracelet or arm-band.
For タク, imagine a metal tack being hammered into a bracelet to shape it: tack -> タク, and the metal bracelet takes form.