GB334267A - Improvements in or relating to methods of, and apparatus for, co-ordinating the feed of a succession of sheets with operations repeated in respect of each - Google Patents

Abstract

334,267. Rainey, A. G. June 1, 1929. Feeding and registering webs. - Feeding- mechanism for sheets of paper is provided with a control device comprising a lightsensitive device and a source of radiant energy, the rays from which are varied in their incidence on the light sensitive device by the introduction into their path of a control area on the sheet and modulate an electric current actuating or controlling the feeding-mechanism. The control area may be the printed design or the like the position of which it is desired to regulate, or other areas of different transparency or reflective properties which may be located at a position offset from the design. As shown in Fig. 1, a web 10, bearing designs and control areas corresponding to each design, is fed over a table 13 by rolls 14, 15 to a cutting- knife 16. The roll 14, on which the web is pressed by the roll 15, is actuated intermittently and the knife is operated during the period when the roll 14 is stationary. The roll 14 is provided with a circumferentially-adjustable pin 17 engaging a pivoted lever 19 formed with an extension 21 which, at the commencement of movement of the roll 14 is raised towards a pivoted lever 22 carrying the roll 15. A tongue 29 is adapted to be inserted between the extension 21 and the lever 22 to enable the roll 15 to be raised when it is necessary to interrupt the field. The tongue 29 is controlled by a solenoid actuated by a relay controlled by a selenium cell 26 or like lightsensitive device. The cell is placed below an aperture 24 in the table over which the web is fed, and the control areas on the web permit more or less light from a lamp 25 or other source of visible or invisible rays to pass to the cell. Preferably, the rolls 14, 15 feed the web more rapidly than is required so that a cumulative error is produced, and when this error reaches a certain proportion, the amount of light reaching the cell is sufficient to actuate the tongue 29 and cause it to lift the roll 15. The light from the lamp 25 is controlled by a slide or the like 27 serving to cut off the light except at the time when the. roll is at rest. Instead of the lamp and device 26 being on opposite sides of the table, they can be arranged on the same side, and the control areas be arranged to uncover a reflecting- surface in the table. The lamp and device may be mounted on diagonal rods, and a diagonal slot be formed in the table in order to enable adjustment to be made for different-sized designs. In a modification, the shaft 50, Fig. 7, of the roller 14 carries a crank 49 supporting a planet wheel 48 meshing with gears 46, 47 on a shaft 43, Fig. 8, and driven by a gear-wheel 41. The shaft 43 carries a ratchet wheel 44 normally held stationary by a pawl 45, and supports an arm 51 provided with a roller held in contact with a cam 53 by a spring 54. The cam depresses the arm when the roller 14 is brought to rest. The arm carries a pawl 55 normally held out of contact with the ratchet but under the control of the armature 57 of a solenoid 32 controlled by the cell 26. When the error in the feed of the web has reached a certain amount, the pawl 55 is forced into engagement with the ratchet and causes a slight backward rotation of the gearwheel 47 and consequent backward rotation of the feed roll 14. The devices mav be modified to compensate for the cumulative error resulting from feeding the web too slowly, and the two forms mav be combined to correct slow and fast feeds. Specification 324,895 is referred to.