SELF ADJUSTING CABLE TENSTONER
Original Publication Date: 1983-Aug-31
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
In many automatic reproducing machines at least one document scanning carriage with an exposure lamp, reflector, etc., is used to scan a document to be reproduced. Typically, the document is scanned at a first speed by the carriage and the carriage is returned to the start of scan position at a speed greater than the first speed by a cable which terminates in a hard mount. On prolonged use as the cable stretches cable tension drops causing a drop in carriage pad to scan rail interface friction which results in increased carriage "flyhack" velocity with the carriage slamming into a fixed stop. To maintain a smoother, quiet and consistent "flyback" operation, it is desired to maintain the tension in the optics cable. This is achieved with the mechanism illustrated in the figure wherein an extension spring 10 fastened to the frame is connected at the other end to the cable 11 which is wrapped around a one way clutch bearing 12 mounted on a shaft 14 to permit the cable to travel only in a direction toward the spring. The one way clutch bearing provides a buffer between the scanning carriage and the extension spring pre-venting any perturbulations that may be caused by spring movement from entering the system. The spring is preferably designed to provide a relatively flat rate of tension over the cable stretch to provide a more consistent cable tension.