PURPOSE: To prevent breakage and noise by providing a permanent magnet inside a cable return disc rotatably provided to a column body and providing electromagnets around the outer circumference of a disc plate attached to the column body.

CONSTITUTION: Cable return discs having guide grooves 21 engaged with a cable are rotatably provided to a column body 1 via bearings 25. At least, a set of electromagnets 24 or a permanent magnet 24' is arranged inside a flange 22 of the return disc 2. Disk plates 13 are attached to the column body 1, the electromagnets 14 are annularly arranged around the outer circumference of the disc plate 13, and the electromagnets 14 are connected to a feed and a control circuit via a control line 15. When the electromagnets 14 are energized in order, magnets 24, 24' are attracted or repelled so as to rotate the return disc 2.