GB423803A - Improvements in or relating to web feeding apparatus - Google Patents

Abstract

423,803. Feeding webs. HORGAN, G. D., and MOLINS MACHINE CO., Ltd., 2, Evelyn Street, Deptford, London. Aug. 9, 1933, No. 22260. [Class 100 (i)] In web-feeding apparatus of the type in which means are provided to feed a web having markings at regularly spaced intervals, the feeding means being operative to feed the web below the correct web speed and having auxiliary web-feeding means to augment the amount of web fed by the main feeding means, a detector is arranged to act on the web and move in the direction of the web at the correct web speed, and whenever the web markings coincide with the detector to co-operate with an element to make the circuit of an electromagnetic device, which circuit is maintained by the co-operation of the detector and the element throughout the time that the electromagnetic device is energized to bring the auxiliary web-feeding means out of operation. The web 1, which is provided with perforations, marks, &c. at recurrent intervals along its length, is fed by rollers 3, 40 to a severing-device 5, the amount fed being slightly less than is required. The web passes over a roller 4 which is divided into two parts freely mounted on the roller spindle 140. A space is left between the two parts in which is mounted a disc 100 rigidly connected to the spindle 140, which is driven at a constant speed synchronous with the cutting-mechanism. The disc carries a spring contact 10 adapted to pass through a perforation in the web when the latter is in register and engage a contact plate 11 arranged around a part of the roller 4, thus completing the circuit of an electromagnet 12. The armature of the latter is connected to a lever 14 which retains a cam-track 15 in position, when the magnet is de-energized, but when the contact 10 passes through a perforation, the cam-track is raised out of the path of a roller 16 carried by a disc 17, which is also rotated synchronously with the cutting means. The feed-roller 3 is driven by the disc 17 by means of a spring- pressed pawl 120 engaging a ratchet wheel fixed to the roller, and additional movement is imparted to the roller when the web is out of register by means of a second pawl 20 slidable in a slot in the disc 17 under the control of the roller 16. When the web perforation does not engage the pin 10, the magnet 12 is not energized, the cam-track 15 remains in the lowered position shown and is engaged by the roller 16 which is pressed inwardly, thus flattening out the pawl 20 and imparting an additional rotation of one tooth to the roller 3. For feeding long blanks, a commutator is provided in the circuit of the magnet 12 which maintains the cam-track raised for a number of revolutions of the feed-roller, but leaves the electromagnet free to be energized or not according to the register of the web during that revolution in which the perforated part of the web is passing over the roller 4. The mechanical feeler may be replaced by a light source carried by the disc and co-operating with light-sensitive cells carried by the shroud 11. Specification 334,267, [Class 100 (i)], is referred to.