GB1336786A - Apparatus and method for winding a running length of thermoplastic web into a series of rolls and rolls of web made therefrom - Google Patents

Abstract

1336786 Winding webs E I DU PONT DE NEMOURS & CO 15 July 1971 [23 July 1970] 33218/71 Heading B8R In a web winding operation, the web running to full core is severed and the leading, severed end heat bonded to a replacement core. The web 31, which may be of thermoplastics material, issues continuously from a processing unit (not shown) and is fed through an accumulator unit 1 and via forwarding means 2, e.g. drive rollers, edge trimmers and a tensioning device, to a wind up unit 3. The web is normally wound at position 3 on a core, supported between air actuable chucks on a rotatable turret 8, a rider roll 6 facilitating this winding operation. When a footage sensor detects that the core is nearly full, the turret 8 is rotated, clockwise as shown, through 270 degrees to position 2 thus moving an empty core, initially at position 1, to position 4. The rider roll is raised, the forwarding means halted and the accumulator begins to collect the issuing web. Powder, which may be present on the web, is cleaned off in the vicinity of the empty core at position 4 by a temporary rotation of that core. A severing unit 4 on an arm 36 is then lowered until a clamp 42 and rubber aprons 46, 47 hold the web to the stationary empty core. A heated wire 41 cuts the web and heat bonds it to the core. The wire is then retracted and an air current cools the web. The severing unit is raised when the accumulator is full to a pre-determined extent, the turret rotates anticlockwise through 90 degrees and the empty core is rotated, at the wind-up position 3 and in contact with the lowered rider roll 6, firstly at overspeed to empty the accumulator, and then at normal winding speed. The above sequence of events is effected by a pneumatic control circuit incorporating pressure valves, electrical limit switches, and a cam sequencer.