Patent ID: 8776491

Claim:
A lifting engagement chain unit, comprising: a plurality of pairs of hooked inner tooth plates disposed with an interval therebetween in a chain width direction; at least two hooked outer tooth plates, each disposed adjacent to and on an outside surface of one of the pairs of hooked inner tooth plates in the chain width direction, such that the plurality of pairs of hooked inner tooth plates are disposed between the two hooked outer tooth plates in the chain width direction; a plurality of pairs of front and rear link pins linking the hooked inner tooth plates with the hooked outer tooth plates, the plurality of pairs of front and rear link pins extending in the chain width direction; a pair of engagement chains being constructed by linking the plurality of pairs of hooked inner tooth plates with the hooked outer tooth plates in a chain longitudinal direction by the front and rear link pins, wherein said pair of engagement chains include a first engagement chain and another engagement chain which are configured to integrate with each other when disposed so as to face each other and engage with each other as the hooked inner tooth plates and hooked outer tooth plates of each of the pair of engagement chains engage with each other, the pair of engagement chains also being adapted to disengage from each other and separate; and a plurality of buckling restricting attachment plates being attached respectively to one of the outside of the hooked outer tooth plates of each of the pair of engagement chains, wherein the plurality of buckling restricting attachment plates are arrayed continuously along the chain longitudinal direction such that each of the buckling restricting attachment plates has a pair of front and rear buckling restricting planes that restrict buckling of the first engagement chain along a corresponding front or rear restricting plane of the other engagement chain of the pair of engagement chains when the pair of engagement chains are engaged with each other.