Multi-joint bending structure and wearable device using multi-joint bending structure

A multi-joint bending structure comprising:

• a first band piece including joint potions on both ends;
• bending units arranged on both sides of the first band piece and each including a plurality of second band pieces each including joint potions provided on both ends and connected with joint potions of other pieces, the bending units enabling the multi-joint bending structure to change in position between a straight state and a bent state;
• a third band piece including a joint potion provided on one end, the joint portion connected to the joint potion of the end of one of the bending units;
• at least one pair of two linear bodies provided on a side of housings of the first to third band pieces, the side becoming an inner peripheral side of the joint potions in the bent state, each of the linear bodies having one end fixed to the housings and another end movable along the housings when the multi-joint bending structure changes in position;
• and
• an assisting force generation mechanism provided at predetermined opposed positions of the pair of two linear bodies and configured to generate assisting force when the multi-joint bending structure changes in position between the straight state and the bent state, wherein
• the assisting force generation mechanism comprises
• rod-like bodies which have an equal length, are fixed respectively onto the pair of two linear bodies, and have non-overlapping portions and overlapping portions that overlap each other across a predetermined gap,
• a contracting elastic body inserted into the gap, and
• two piece members which each have an outer shape larger than the gap, and which are connected to both ends of the elastic body and energize both ends of the overlapping portions of the rod-like bodies by contracting force of the elastic body, and
• after the elastic body is extended to the maximum in the course of movement of the pair of two linear bodies in opposite directions while the multi-joint bending structure changes in position between the straight state and the bent state, both the ends of the overlapping potions energized by the piece members switch over, and the contracting force of the elastic body acts as the assisting force between both the ends.