GB761134A - Improvements in the production of slit reels of flexible sheet material - Google Patents

Abstract

761,134. Feeding webs. BRITISH CELLOPHANE, Ltd. June 4, 1954 [June 11, 1953], No. 16147/53. Class 100(1) A web 11 of flexible sheet material, e.g. polythene or cellulose acetate, is unwound from a roll 14 which is continuously reciprocated in an axial direction within adjustable limits defined with respect to longitudinal slitting devices (not shown) such that when the web 11 is rewound portions of increased thickness are not spaced directly above one another, but are laterally offset. Longitudinal slitting devices are positioned in planes 2 and 7 in order to trim the marginal edges of the web 11. In one embodiment, jets 15 and 17, supplied with compressed air, are arranged above boxes 16 and 18 respectively. The boxes 16 and 18 are connected by pipes 20 and 21 to a bellows 26, 27 which operates a valve 22 which admits liquid under pressure from a pump 122 to a cylinder 23 having a piston connected by a coupling 24 to the axle 25 of the roll 14. When compressed air from the jet 15 reaches the box 16, due to movement of the edge 12 of the web 11 moving to right, the bellows 26, Fig. 3, is inflated to rock an arm 28 about a pixot 29, thus lifting a link 40 pivoted to a link 41 having pivots 42 and 44. A wheel 45 carrying a flap 46 is given a sudden counterclockwise rotation due to a spring 47 when the line joining pivots 43 and 44 is positioned above the pivot 42, such that an aperture 30 is closed. As a result a vacuum pump 33, Fig. 2 is connected to the valve 22, such that liquid is admitted to the right hand side of the cylinder 23, thus causing movement of the axle 25 and roll 14 to the left. When the edge 13 of the web 11 passes beyond jet 17 the valve 22 is operated in a similar manner by inflation of the bellows 27 to admit liquid to the left of the piston within the cylinder 23. Thus, the roll 14 is continuously reciprocated between limits defined by the distance apart of the jets 15 and 17 which may be adjusted in known manner. In a modification, the arm 28, Fig. 3, operates the valve 22, Fig. 2, by a mechanical linkage. Other detectors such as mechanical contacts, electrical contacts, vacuum or compressed air arangements in which the web edge closes an aperture, photo-electric cells, and capacitative 'arrangements in which passage of the web between condenser plates varies the capacitance of the condenser, may replace the boxes 16 and 18 and air jets 15 and 17. A servomotor actuating the roll 14 may be actuated by hydraulic, pneumatic or electrical means. Specifications 462,960 [Group XXIX], 687,932 and U.S.A. Specification 2,269,884 are referred to.