A double-walled insulated mug for your favorite hot beverage. Housed between the walls opposite the handle is a mechanism with three functions: indicating the temperature of the beverage, playing a short melody at each of three selected temperatures, and stirring the beverage in the mug.
bimetallic strip moves in response to the internal temperature. The movement of this strip slides an indicator across the temperature display window, which is an arc-shaped area of the external wall of the mug left un-silvered on the inner surface.
At three different selected temperatures, triggers riding the back of the bimetal strip are released as the end of the strip passes; this allows the playing of a short melody from a music-box style metal harp. Only a short passage is played, as the melody is encoded with pegs covering 1/3 the circumference of the cylinder. At the end of the section, the cylinder is halted until the next trigger is released.
The speed limiter for the music-box mechanism consists of a tube with a splined interior, sealed to the inner wall of the mug, into which a shaft with vanes is inserted. As the music plays, the tube spins the shaft, stirring the drink. This shaft is held in place by a ball and detent; it can easily be removed for cleaning.
Fluid resistance against the vanes is balanced by a spring mounted to the frame for the metal harp. If the vanes overspeed, the spring lifts the harp away from the pegged cylinder, resulting in no music playing if the mug is empty.
A folding key mounted to the outside of the mug allows winding of the mechanism. As the key is wound, the triggers are reset for operation, and the music-box cylinder returned to its starting position. The key can be folded either up or down; a lever below the key mechanism holds the harp in the up position resulting in a "silent" mode. Folding the key downward holds the lever in this mode. The temperature display and stirring mechanism are still functional.
The triggers, which are visible in the display, can be moved to desired set points by pressing the key partway in, turning the pointer to the desired trigger, pressing the key farther, and turning to the desired point.