Patent ID: 7639478

Claim:
A media playing device comprising: a hollow turning knob with a cylindrical inside surface having two spaced contacting protrusions extending radially inwardly therefrom; a housing including a cylindrical end portion having an opening in a lip thereof, the opening providing space for accommodating the contacting protrusions; a PCB disposed within the housing, the PCB having a micro controller unit and two switches having distal ends being exposed through the opening, the switches being contacted to be activated to send a signal to the micro controller unit, the micro controller unit executing an operation in response to the signal; attachment means on an outside surface of the end portion and the cylindrical inside surface configured for attaching the hollow turning knob to the housing and allowing a relative rotational movement between the hollow turning knob and the housing; wherein the media playing device further comprises a torsion spring, the housing has a spring attachment means for attaching the torsion spring to the housing and defining a range in which two legs of the torsion spring move; wherein, when the torsion spring is attached to the housing, ends of the two legs of the torsion spring contact the two contacting protrusions when the torsion spring is in a compression state; and wherein the spring attachment means comprises a wall and a post, the wall and the post extend axially from a planar portion adjacent the opening, the planar portion extends radially inwardly from the inside surface of the housing, the post is configured for retaining the coiled portion of the torsion spring, the wall has a cutout whose two rims are configured for clamping the two legs of the torsion spring.