Transmission belt and indication apparatus for indicating the end of life of transmission belt
A transmission belt ( 10 ) has a contact face ( 18 a ) which contacts a pulley when the belt ( 10 ) is wound around the pulley. Foreign matter ( 25 ) is embedded near the contact face ( 18 a ) in the belt ( 10 ). The contact face ( 18 a ) is worn by the pulley when the belt ( 10 ) rotates around the pulley, so that the foreign matter ( 25 ) is exposed at the contact face ( 18 a ). The foreign matter ( 25 ) contacts the pulley to make a warning sound. Due to this, a user of the belt ( 10 ) can determine the extent of the wear of the belt ( 10 ), and the decrease in the transmissibility of the belt ( 10 ) and the pulley.
1. 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.
2. A transmission belt according to claim 1 , wherein said foreign matter is softer than said pulley.
3. A transmission belt according to claim 1 , wherein said pieces of foreign matter have a cross section of variable width such that the width of said foreign matter is narrower for portions of said foreign matter closer to said contact face and wider for portions of said foreign matter farther from said contact surface.
4. A transmission belt according to claim 1 , wherein said pieces of foreign matter are given a color, which is different from a color of other parts of said transmission belt.
5. The indication apparatus of claim 1 wherein said pieces of foreign matter are completely embedded within said transmission belt.
6. An indication apparatus for indicating the end of life of a transmission belt, comprising:
a pulley;
a transmission belt that is wound around said pulley having;
a contact face contacting said 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 whereby said foreign matter contacting said pulley makes a specific sound;
a sound sensor, which detects said specific sound, set up near where said transmission belt contacts said pulley; and
a warning apparatus which sends out a warning according to the volume or sound pressure of said specific sound detected by said sound sensor.
7. An indication apparatus according to claim 6 , wherein said foreign matter contacting said pulley at a predetermined cycle makes a specific sound appear at said predetermined cycle when said transmission belt rotates at a predetermined speed.
8. An indication apparatus according to claim 7 , wherein said warning apparatus sends out a warning when said specific sound appears at said predetermined cycle.
9. The apparatus of claim 6 wherein said pieces of foreign matter have a cross section of variable width such that the width of said foreign matter is narrower for portions of said foreign matter closer to said contact face and wider for portions of said foreign matter farther from said contact surface.
10. The indication apparatus of claim 6 wherein said pieces of foreign matter are embedded entirely within said transmission belt.