MASTER LINK

PURPOSE:To reduce the wear of a master pin for connecting a track link plate and a master link plate in a master link. CONSTITUTION:A pin insertional hole 13c of a track link plate 10c has an inner diameter to be fitted with a master bush 12, and a master link plate 10d is equipped with a small diametral part 13dS where a master pin 11 is inserted through, as the pin insertional hole 13d, and a diametral expanded part 13dS in which the master bush 12 is insertable, while a ringlike collar 15 is pressed in the diametral expanded part 13dS in the pin insertional hole 13d of the master link plate 10d, and this collar 15 is substantially unified with the master link plate 10d. An inner diameter of this collar 15 is formed into almost the same size with the small diametral part dS, and in consequence, a master pin 11, in relation to the master link plate 10d, comes to slide not only the small diametral part 13dS but also the collar 15 unified with this master link plate 10d, in substance.