US Patent 7909281 Wire-winding device having a circuit unit

A wire-winding device includes a circuit unit, a wire-winding disk, two cables, a scroll spring and a circuit unit. The insulating body has receiving space. The wire-winding disk is rotatably located in the receiving space. The wire-winding disk has at least one concave slot. There is a rolling ball between the concave slot and the insulating body. The scroll spring is connected between the wire-winding disk and the insulating body. The circuit unit is located in the wire-winding disk and is electrically connected with the two cables. Thereby, the user can rapidly receive or lease the cable to adjust the length of the cable, and use the circuit unit to convert the input voltage or current into a desired voltage or current for outputting.