Textile thread length control process - controls speed of thread unwinding from reel using mechanical control and photo-resistive detector

摘要

Continuous measurements are made of the dimensional variations of a textile thread which is used in a process. This is performed by making the thread pass between points upstream and downstream of the process and altering the speed to maintain a constant length between there points. A thread (1) unwinds from a reel (2) to pass through a braking system (3) to present a light tension onto the thread prior to its passage through a drive unit (4) and tensioner (5). A lower pulley (5c) on the tensioner has a weight (8) attached and articulates at the end of a beam (9). The beam contains a photo-resistance (13) activated from a lamp (14) to allow the length of thread to be determined. The photoresistor provides signals to control the drives (4, 7) to control speed of the thread.