Patent ID: 8500101

Claim:
A pair of engagement chains, each comprising: a plurality of inner link units each including a bush press-fitted into a pair of bush press-fitting holes formed in the chain longitudinal direction of a pair of inner tooth plates having hook portions and being disposed apart from each other in a chain width direction; at least two outer tooth plates, each having hook portions and a pair of pin holes formed in the chain longitudinal direction, and each being disposed respectively on each outer side of the inner link unit in the chain width direction while being shifted by a half pitch in the chain longitudinal direction with respect to the inner tooth plates; at least two inflection restricted plates, each having an inflection restricted surface on a hook engaging side of the inner tooth plates and the outer tooth plates; and at least two inflection restricting plates, each having an inflection restricting portion that projects toward the inflection restricted surface of the inflection restricted plates so as to abut with two adjacent inflection restricted surfaces of two adjacent inflection restricted plates in the chain longitudinal direction; and connecting pins fitted into the bushes and the pair of pin holes to link the inner link units, outer tooth plates, the inflection restricted plates, and the inflection restricting plates in the chain longitudinal direction, wherein the pair of engagement chains are integrated by the hook portions of the inner tooth plates and the hook portions of the outer tooth plates being brought into contact so as to respectively engage with each other by a pair of driving sprockets that engage with the bushes, wherein the pair of engagement chains are branched when the hook portions of the inner tooth plates and the hook portions of the outer tooth plates are disengaged respectively by being deflected by said pair of driving sprockets, and wherein the inflection restricted plates are arranged in parallel with the outer tooth plates, and the inflection restriction plates are arranged in parallel with the inner tooth plates between the outer tooth plates and the inflection restricted plates.