Patent GB-384675-A (GB)
Title: Improvements relating to printing presses
IPC: B65H23/04
Filed: 1931-06-11
Abstract: 384,675. Feeding webs. CRABTREE & SONS, Ltd., R. W., Water Lane, Leeds, and SMITH, E. W., 29, Chartenhall Road, Edinburgh. June 11, 1931, No. 17044. [Class 100 (i).] Means for controlling automatically the register of an inset web with other printed webs comprises registering marks &c. printed on the inset web which co-operate with one or more light apertures formed in one part of a compound roller over which the web passes, and which is composed of a plurality of relatively rotatable parts, having means whereby when register of the light aperture and the marks on the web is disturbed, the relative disposition of the parts of the compound roller is automatically adjusted. Light from a source m passes through a hollow shaft a on which is mounted a compound roller i, d, j, comprising a ring d, formed with a light aperture d<1>, and fixed to the shaft a, and two rotatably mounted drums i, j on each side of the ring d. A system of prisms and lenses attached to the shaft a and ring d is such that the beam of light entering at one end of the shaft passes through the first lens tube e, and after reflection at the aperture d, travels through the second lens tube e<1> and the shaft a, emerging at the other end to fall upon a light-sensitive device n. The current produced therein passes to two thermionic amplifying valves, the output circuits of which are normally balanced but which, when the amount of reflected light is abnormal, determine the operation of a reversible electric motor to effect the control of the speed of rotation of the parts i, j of the compound roller. The web q passes over two intermediate rollers which carry gears is, j<3> at each end and are arranged both before and after the compound roller i, j, and the gears i<3>, j<3> engage pinions i<2>, j<2> mounted on the ends of the cylinders i, j and pinions i<4>, j<4> on a counter-shaft k which receives a drive from a variable speed gear preferably of the positive infinitely variable type suitably controlled by the electric motor under the action of the light-sensitive device. The gear employed is preferably of the kind described in Specifications 228,838, 242,416, and 259,058, [all in Class 80 (i), Gearing, Belt &c.]. When the web q is in register, the amount of light falling upon the device n is such that the two controlling valves of the motor are balanced and the motor is at rest. When the amount of light from the web is in excess, the motor rotates in one direction while when it is less than normal the motor rotates in the opposite direction. Two or more light apertures and corresponding lens systems may be provided such that when one aperture passes from beneath the web another is brought into effective relation. The light-sensitive device may be rendered inoperative while the light aperture is not covered by the web or alterna.- tively the intensity of the light beam may be maintained at its normal value. The time when the light aperture is uncovered may be rendered so short as not to affect the light-sensitive circuit or damped relays may be provided to ensure that only a persistent variation in the masking of the light aperture affects the control circuit.