GB527071A - Improvements in a machine for applying adhesive to web material - Google Patents

Abstract

527,071. Coating webs; printing. AMERICAN CAN CO. May 12, 1939, No. 14198. Convention date, May 19, 1938. [Class 140] [Also in Group XVI] A machine for applying a pattern of fluid thermoplastic adhesive to a web comprises a receptacle for the adhesive, heating means therefor, a rotable intaglio roller for transferring adhesive from the receptacles to the web, and a movable carriage for the roller arranged to allow the roller to be moved in and out of the receptacle. As shown a web A is fed by pairs of feed rollers E rotated in unison through the adhesive applying unit in which a pressure roller F presses the moving web against an intaglio roller G, the web being tautened by passage over the idler roller H. The intaglio roller G rotates in a heated bath 51 containing fluid thermoplastic adhesive, excess adhesive being removed from the intaglio roller by the doctor blade J. The idler roll H, pressure roll F and intaglio roller G are mounted in a carriage 63, Fig. 9, which is locked in the operative position by latches 70, and which can be swung back, after disconnecting the hooks 195 of the doctor positioning device 201, 196, 198, to expose the rolls for cleaning. As shown the intaglio and pressure rolls G, F are hollow and constructed for the circulation of heating and cooling media respectively, the bearing for these rollers also being constructed for the circulation of a cooling medium. An auxiliary motor 161 is provided for continuing the rotation of the intaglio roller in its bath of adhesive at a slow speed when the normal operation of the machine is suspended, timing means' being also provided to accelerate to full speed in phase with the remainder of the machine when the machine is restarted, the web material being brought against the roller at the proper place to continue application of the pattern. The pressure roll F is held in position when the machine is running by means of a pressure block 236 disposed in slideways 223. The blocks carry cam rollers 242 which engage wedge cams keyed to a cam shaft 245 which is held under torsional force by springs. In normal operation the torsion springs are held against rotating the cam shaft by a trip device consisting of a tooth and pawl which is locked by the force exerted by an electric solenoid in the main motor circuit, on breaking the main circuit the solenoid is de-energized, the pawl is released and the turning cam shaft releases the cam rollers 242 thus allowing compression springs to raise the pressure roller F by sliding the pressure blocks 236 up the slideway 223. On starting the machine the auxiliary motor 161 is started first and it runs continuously, driving the intaglio roller G slowly through a clutch system. On starting the main motor its drive is over-run but still operates through the clutch system. The drive on the intaglio roller G is brought into phase with the main drive on the main-shaft 37 by means of a pawl co-operating with a single toothed ratchet on that shaft.