GB1146697A - Control for a band feeding device - Google Patents

Abstract

1,146,697. Feeding webs. HUNTER DOUGLAS INTERNATIONAL Ltd. 23 March. 1966 [23 March, 1965], No. 12846/66. Heading B6B. A web of material is fed in-steps to a working station and the length of material fed during a step is automatically adjusted by an electrical control system in dependence on a signal, stored in a memory, corresponding to the relative position of a mark on the web detected previously, so that operation takes place at the same relative position at the station. In Fig. 1,aluminium strip 1 bearing registration marks is fed to a machine 8 in which it is stopped periodically and crown caps formed by operation of a punch driven by a shaft 7. The marks are viewed by a photo-electric detector 3 before they reach the punching position and the timing of the electric pulses so produced is compared in a comparator 4 with pulses produced by a transmitter 5 operated by the machine. Transmitter 5 is adjusted so that normally no output is produced by comparator 4. Thereafter, any variation in the position of the marks exceeding a predetermined value results in outputs 28a, 28b or 28c from comparator 4, according to the sense and magnitude of the variation, which are applied to a relay-type memory device 25. Memory device 25 is controlled by rotary switches S 1 -S 3 operated by the machine -so that the variations are stored periodically and released to operate appropriate magnets or fluid-pressure operated members 15, 16 or 17 which increase or decrease the -amount of strip fed during the step into the station as necessary to ensure that punching occurs at the correct position. Details are given of a relay memory device for use when the mark ahead of that being viewed is at the punching station. More complex memory devices giving greater accuracy of correction and/or operation when there are several marks between the viewing and punching positions -are referred to.