Engagement chain and movable body movement device

An engagement chain comprising at least two chain members that are capable of selectively advancing and retreating, wherein

• the chain members are engaged to be integrated with each other by moving in an advancing direction,
• the chain members are disengaged from each other to bifurcate by moving in a retreating direction from an engaged state in which the chain members are integrated with each other,
• each of the chain members includes a plurality of link plates, each having two pin holes, and a plurality of coupling pins,
• each of the chain members is configured by pivotally coupling the link plates in series by the coupling pins in the pin holes,
• the two pin holes of each link plate are aligned in an advancing/retreating direction of the chain members and are sized differently from each other,
• each of the coupling pins of each chain member is tightly received in the smaller one of the two pin holes of one of any adjacent two of the link plates in the advancing/retreating direction and is loosely received in the larger one of the two pin holes of the other one of the two adjacent link plates, and
• in a state in which the chain members are engaged so as to be integrated with each other, any two of the coupling pins that are opposed to each other in a direction perpendicular to both the advancing/retreating direction and a direction in which each coupling pin extends are in the same received states in the corresponding pin holes.