Patent GB-429218-A (GB)
Title: Improvements in and relating to mechanism for controlling the register and cutting of printed webs of paper or the like
IPC: B26D5/34
Filed: 1934-03-23
Abstract: 429,218. Feeding webs. PACKAGE MACHINERY CO., 132, Birnie Avenue, Spring- field, Massachusetts, U.S.A. March 23, 1934, No. 9127. Convention date, April 21, 1933. [Class 100 (i)] In a device for controlling the registration of webs of paper or the like by the coaction of indicia on the web with a detecting-device, in which means are provided for feeding the web and also means associated with a ratchet for introducing a correction into the web-feeding means, the ratchet being actuated by a pawl mounted on a positivelyoperated pawl-carrier, the actuation of the ratchet is controlled by a follower spring held against the pawl for normal travel therewith and operable when so held to hold the pawl out of contact with the ratchet, means responsive to the condition of registry of the web being provided for holding the follower from travelling with the pawl during a power stroke of the pawlcarrier. The web 20, Fig. 1, supplied from a reel 21 passes over a spring- pressed roller 24 and guide roll 27 past a photo-electric cell which controls the register-correcting mechanism and is situated approximately at the edge of the web in a support which is carried by a casing attached to the end of a curved guide over which the web passes, and which is adjustable transversely thereto. The web then passes between feed rollers 40, 41, which are geared together and of which the roller 41 is positively and continuously driven, and is fed to cutting-apparatus comprising a stationary lower knife 45, Fig. 2, and a revolving upper knife 46, before being seized by feed belts 47, 48 which convey the cut sheets to the machine. The upper feed roller is formed of a number of longitudinally spaced short rolls mounted on a common shaft and made of cork, while the lower roller is of steel. The feed roller 41 is driven from a shaft 150 through gears 149, 148, 145 which can be changed to vary the rate of web feed, and the gear 145, Fig. 4, drives a gear 59 fixed to a sleeve 57 which is loose upon the shaft 49 of the roller ; a housing 53 is rotatably mounted upon the sleeve 57 and contains pinions 62 which rotate upon shafts 55 in the housing and mesh with a pinion 61 attached to the sleeve 57. Integral with the pinions 62 are larger pinions 63 meshing with a pinion 51 fast on the roller shaft 49, so that if the casing 53 is held stationary, the gear 59 drives the shaft 49 at a constant speed, but when the casing is rotated, the difference in the sizes of the pinions 62, 63 causes a relative advance or retardation of the shaft 49 depending upon the direction in which the casing is moved. The feed rollers are arranged to feed more web than is required, and the housing is periodically rotated to effect correction of the feed. This is obtained by a ratchet-and-pawl mechanism controlled by the photo-electric cell. The ratchet 75, held against backward movement by a spring-pressed pawl, is connected to a gear meshing with the gear 77 on the casing 53 and is operated when necessary by a pawl 92 carried at one end of two-armed lever 78, which is pivoted on a stud 70, and carries at the other end an adjustable pivot 80 connected by a link 82 to a crank pin 83 rotated from a shaft 90 at a constant rate. The pawl 92 is normally held from engagement with the ratchet 75 by an abutment 100 which is spring-pressed against the end of the pawl and holds it away from the ratchet : the abutment 100 is rigidly connected to a dog 102, and a pivoted latch 105 can be brought into the path of the dog 102 to hold the abutment 100 from the pawl 92, which is thus permitted to engage the ratchet 75 during a forward stroke of the pawl arm 78. Movement of the latch 105 into locking position is brought about by an electromagnet 113 which when energized attracts its armature 112, which is in engagement with a projection 106 carried by the latch 105. By suitably timing the energization of the magnet 113, the latch 105 can be brought into position to engage with the projection 102 towards the end of the inactive stroke of the pawl arm, so that the pawl engages the ratchet for the next active stroke and is brought out of engagement towards the end of the next inactive stroke, the energization being controlled by the photo-electric cell which is mounted in a casing formed with a slit and provided with a longitudinally-slitted cylindrical shutter, which is rotated once during each cycle by adjustable elliptical gears so arranged that the shutter is moving with the speed of the web when the slit comes adjacent thereto. When the web is in correct register the opaque indicia marks provided thereon come between the adjustably-mounted light source 128 and the slit in the shutter, so that no current flows in the photo-electric cell circuit, consisting of a rectifier and amplifier valves and of a gas-filled relay valve of known type to the grid of which are applied the amplified current impulses set up by light falling on the photo-electric cell through the shutter slit when the indicia marks on the web do not register therewith. In the passage of such an impulse, current flows in the plate circuit of the relay valve energizing the electromagnet 113 and causing the pawl 92 to engage the ratchet 75 so that during the next operative stroke of the pawl arm 78 the casing 53 is rotated to introduce a definite amount of correction into the feed. The plate current of the relay valve is interrupted towards the end of the machine cycle to cause the electromagnet to be de-energized, so that when the pawl 92 strikes against the abutment 100 during its inactive stroke, the latch falls and the abutment is released ; the electromagnetic circuit is broken by means of cam-opened contacts included in the circuit, so that the device is re-set prior to the arrival of the next control spot on the web. The mechanism may also be arranged so that the ratchet 75 is operated whenever a spot is in proper position and inactive when a spot is out of register. The cutters comprise a fixed lower knife 45, Fig. 2, bevelled at 158 and set at a slight angle transversely of the web, and a rotary upper knife 46 bevelled at 162 and also slightly bevelled on the other side, this bevel increasing progressively from one end of the blade to the other. The cutting edge of the blade 46 is arranged to be displaced angularly around the axis of the cylinder 161 so as to correspond to the angular arrangement of the knife 45, and in order to drive the knife-carrying cylinder 161 at a higher speed than the web at the instant of cutting, the cylinder is driven by adjustable elliptical gears from the driving- shaft 150. Specification 429,647 is referred to.