Apparatus for winding or unwinding webs of photosensitive material or the like

摘要

Apparatus for winding webs of photographic film like onto the hub of a reel in a cassette has a flexible band one end of which is secured to the hub and the other end of which is connected to a coupling unit having a normally closed clamping mechanism for the leader of a web. The leader can be threaded through an inlet opening of the cassette and into the coupling unit when the clamping mechanism is held in open position by a permanent magnet which is installed in the cassette adjacent to the opening. When the hub is rotated in a direction to convolute the band and thereupon the web therearound, the coupling unit is withdrawn from the field to the permanent magnet and is confined in a peripheral recess of the reel. If the web is thereupon unwound, the coupling unit is withdrawn from the recess and is advanced toward the opening so that the magnet opens the clamping mechanism and the latter permits withdrawal of the leader of the web therefrom. The clamping mechanism thereupon remains open until an operator inserts the leader of a fresh web and causes the hub to rotate in a direction to collect the band.