PURPOSE: To improve the parallel condition of a filament group and to increase the physical properties such as the cord strength utilization factor of a reinforcing fiber cord and dimensional stability and so on by properly setting the relationship of twist multiplier between final twist and first twist of a filament group for forming a tape-like fiber bundle.
CONSTITUTION: A toothed belt 1 comprises a back rubber 2 extended in its longitudinal direction and plural core wires 3 buried in the back rubber 2, wherein plural toothed rubbers 4 are disposed by suitable pitch on the back rubber 2, and a cover canvas 5 is made adhere to the surfaces of the back rubber 2 and the toothed rubbers 4. As a reinforcing fiber cord as the core wire 3, for example, organic fibers such as Aramid fiber, polyarylate fiber and so on are used. A filament group forming a tape fiber bundle as the core wire 3 is formed by applying first twist with the twist multiplier which is less than one-third the twist multiplier K=T(D)1/2 of final twist [T: twist frequency per 10cm, D: denier number of fiber bundle] and with K=100 or more, and then applying final twist in the opposite direction to the first twist.
KAWAHARA HIDEAKI
OCHIAI MASAKI
