Patent ID: 7556577

Claim:
A wire reciprocating device, comprising: a pair of guide members; a reel drum provided between the guide members; wires wound around the guide members and connected to the reel drum to be reeled onto the reel drum in directions opposite to each other; a moving body connected to the wires and reciprocated by rotating the reel drum in a direction and a direction opposite thereto to rotationally run and reciprocate the wires; a pair of tension rollers pressed onto respective portions of the wires extending from the reel drum in directions opposite to each other; roller holders rotatably supporting the respective tension rollers; and a tensioner case provided in the vicinity of the reel drum and including a biasing unit for biasing the roller holders so that the respective tension rollers are pressed onto the wires, the tensioner case allowing the tension rollers and the roller holders to move in directions substantially orthogonal to the respective wires when the wires are tensioned, wherein the tensioner case includes a tensioner body and a tensioner cover facing each other, the tensioner body and the tensioner cover include a pair of guide grooves extending in a direction substantially orthogonal to each wire when the wires are tensioned, the paired guide grooves are provided in respective portions facing each other and sandwich each tension roller and each roller holder, each of the roller holders is slidably fitted into the paired guide grooves, which allows the roller holders to slide in the direction that is substantially orthogonal to each wire when the wires are tensioned, a space between lower edges of side portions of the tensioner body and the tensioner cover on each side of the reel drum is closed by a bottom piece extending from the lower edge of the tensioner body toward the lower edge of the tensioner cover, and gaps between the bottom piece and outer circumferences of collars on both ends of each tension roller in a state where each roller holder reaches a lowest position of the pair of guide grooves extending substantially vertically are set smaller than a diameter of the wires.