Patent ID: 7387118

Claim:
A wire saw having a row of wires formed by winding wire about a plurality of work rollers provided to a swinging disk many times, for causing the wires of the row of wires to reciprocate or travel in one direction at high velocity, for pushing a workpiece against the row of wires to cut the workpiece into a plurality of pieces, and for swinging the row of wires in cutting of the workpiece, wherein a feed side pulley located on a side of feeding of the wire to the work rollers and a retrieving side pulley located on a side of retrieving of the wire from the work rollers are provided to the swinging disk so as to swing together with the swinging disk, two outer pulleys for guiding the wire to the feed side pulley and for guiding the wire from the feed side pulley to the work rollers are fixed and disposed on an outer side of the feed side pulley, two outer pulleys for guiding the retrieved wire from the work rollers to the retrieving side pulley and for guiding the wire from the retrieving side pulley to an outside are fixed and disposed on an outer side of the retrieving side pulley, and the feed side pulley and the retrieving side pulley are located with respect to each other so that respective distances between the feed side pulley and the retrieving side pulley and the respective corresponding outer pulleys increase and decrease in directions for canceling out tension fluctuations in the wire according to the tension fluctuations in the wire due to increase and decrease of the distances between the work rollers and the outer pulleys in swinging of the swinging disk.