GB1225561A - - Google Patents

Abstract

1,225,561. Cardboard tubes. LHOMME S.A. 23 Jan., 1969 [7 Feb., 1968; 25 Oct., 1968], No. 4025/69. Heading F2P. A process for the manufacture of smoothsurfaced cardboard tubes to precise dimensions includes the initial manufacture of a basic tube by helically winding on a mandrel 3 a plurality of strips 4, 5a-5j of fibrous material suitably gummed, and then successively winding on the basic tube a gummed strip 6 of low-density fibrous material and a strip of dense fibrous material 7 which is slightly gummed so as to constitute a rough tube having an external diameter slightly greater than that desired. The rough tube is sanded, at 15, and coated, at 16, with a heat-hardening resin 23 to which a polymerization catalyst, if desired, has been added; the tube then being cut into lengths which are stored to evaporate the solvents at a temperature below the polymerization temperature, each length then being passed through a heated matrix 26 to provide simultaneously, by the polymerization of the resin, its final gauging and surface finish. As shown, the initial strip 4 and ten gummed intermediate strips 5a-5j are wound on to the mandrel 3 by a spiral winder 2, which carries two-spindled reels furnished with gumming devices for the strips 5a-5j, the basic tube so formed then receiving the penultimate feltcard layer 6, which is of regular thickness and the final layer 7 of slightly wider absorbent paper which has a chamfered edge 70. The tube is moved axially by an endless belt 11, the coating device 16 having a roller 21 partly immersed in an aqueous solution of heat hardening phenol resin, to which a polymerization catalyst and preferably a lubricating agent, is added. The tube, which at this stage is from 1-2% over nominal diameter, passes to the cutting machine and then to the stove. The dried tube lengths are then fed to the surfacing matrix 26, Fig. 4, where an hydraulic jack 25 successively pushes the tube sections through an accurately sized bore 26a which has a chrome surface and which is surrounded by a heated fluid 33. In a modification both edges of the strip 7 are chamfered.