GB691433A - A device for applying adhesive to an intermittently moving web - Google Patents

Abstract

691,433. Coating webs. DEWEY & ALMY CHEMICAL CO. April 3, 1951. [Aug. 18, 1950] No. 7751/51. Class 140. A device for applying adhesive to a web which is advanced in a succession of steps comprises an applicator roll in constant contact with the web, means for supplying said roll with adhesive, power means for driving said roll through a transmission at a comparatively slow speed less than that attained by the web during its advancement, the transmission either (a) being so constructed as to permit the roll to over-run its drive due to the pull of the web during its advance or (b) embodying means for interrupting the drive during each advance of the web or during a succession of advance movements of the web. The device may be incorporated in a box-taping machine wherein a paper tape is coated with an aqueous dispersion of an adhesive resin and immediately pressed on to the joint of a moving box blank, the continuous rotation of the roll preventing the building-up of deposits of resin on its surface. Tape 23 is led from a supply roll (not shown), and over appropriate guide rolls to a tensioning device 35. It then passes under a guide 36, over the upper quadrant of a coating roll 10 dipping in adhesive in a tray 16, and into a conventional tape feed mechanism indicated by the roll 40 at which point it is applied across the joint of box 37. After the end of the tape has been stuck to the box, the tape is pulled through this entire train by the forward movement of the box imparted through drive chain 38 and push slat 39. The tape is severed by knife 41 which is automatically timed. The timing may be initiated by a device 42 which lifts as the as the box 37 passes beneath it. While the tape is stationary, the roll 10 in contact with it is slowly rotated by a low speed motor 17 through a drive train which includes an overrunning clutch. When the tape is pulled forward by the movement of a box, this clutch permits the roller 10 to be rotated at a higher speed by contact with the moving tape. The film of adhesive on the roller 10 may be controlled by an adjustable doctor bar, knife, or roller. The roller may be constantly driven from the shaft of motor 17 through a universal joint connection, e.g. a coil spring. Metal fingers 43 hold the tape against the roll 10. In modifications, the mechanical overrunning clutch may be replaced by an electrically energized magnetic clutch, or the gear and clutch drive may be replaced by a friction drive brought into and out of operation by a solenoid, which is controlled by a sensing switch, e.g. one mounted to respond to the lifting motion of the wheel sensing finger 42. The roll is normally driven slowly, but when a box comes along, the switch opens, the solenoid is de-energized, the friction wheels disengage, and the roll 10 is freed to be rotated by the tape. The solenoid may be energized through a relay connected across the main drive control circuit so that the roll 10 is free while the main machine operates but is rotated slowly when the main machine stops.