Apparatus for treatment of webs of photographic material

摘要

A web of photographic paper is trained over several rollers so that it can be advanced along a meandering path through successive chambers in a developing machine. At least one of the rollers is mounted on a driven shaft with the interposition of a coupling which engages the shaft with the roller when the tension of the running web which is trained over such roller exceeds a certain value. The roller is normally held against rotation under the action of the web and/or under the action of the bearing which is rotatable on the shaft and yieldably maintains the roller in a position of coaxiality with the shaft. A braking device for holding the roller against rotation has a first plastic ring which is rotatably mounted on the shaft and is connected to or made integral with the bearing for the roller, and a second plastic ring which surrounds and is in frictional engagement with the first ring. The second ring is held against rotation with the first ring by a partition or by another stationary part of the machine.