Patent ID: 8002659

Claim:
A transmission belt comprising: a contact face contacting with a pulley when said transmission belt is wound around said pulley, and a piece of foreign matter embedded near said contact face and at a distance from said contact face in said transmission belt; wherein said piece of foreign matter has a longitudinal direction and said longitudinal direction of said foreign matter is substantially in the direction perpendicular to said contact face; wherein a plurality of pieces of said foreign matter are embedded in said transmission belt, each said piece having a longitudinal direction and a top, and said longitudinal direction substantially in the direction perpendicular to said contact face and with said top closest to said contact face, and each piece having the same length in said longitudinal direction; and a distance in the perpendicular direction between said contact face and the top of at least one piece of said foreign matter being different from a distance in the perpendicular direction between said contact face and the top of another piece of said foreign matter such that upon said contact face being worn by said pulley when said transmission belt rotates around said pulley, then said foreign matter is exposed at said contact face so as to warn of a decrease in the transmission power of said transmission belt on said pulley, wherein said foreign matter contacting said pulley makes a warning sound that becomes louder as said contact face becomes more worn to warn of a decrease in the transmission power.