GB1203041A - Improvements in or relating to apparatus for controlling the unwinding of web - Google Patents

Abstract

1,203,041. Feeding webs. R. A. BUTLER. 30 Aug., 1967 [2 Sept., 1966], No. 39632/67. Heading B8R. Web-roll changing apparatus as described in Specification 1,136,951 is provided with a web accumulator 30 having a double or triple roller configuration which approximately doubles or trebles the storage capacity of the accumulator of the above referred to Specification. In the double roller configuration, Fig. 1, four pairs of dancer rollers 54, 62; 56, 64; 58, 66; and 60, 68 and four pairs of idler rollers 38, 46; 40, 48; 42, 50 and 44, 52 comprise the accumulator 30. The outboard, dancer and idler rollers have a larger diameter than the inboard rollers, and the web path defined between them comprises two interleaved sinusoidal paths. The triple configuration has three such interleaved paths (Figs. 9 and 10). The dancer rollers are journalled between two end plates 72 arranged for vertical movement by roller bearings on two spaced vertical guide rails 82. Each end plate 72, Fig. 3 is fastened into an endless chain 104. A pneumatic piston 128 moves the dancer rollers vertically upwards via a chain 136, sprocket 138, shaft 122 and sprocket 116. Two cams 140 and 146 journalled to the shaft 122 form part of the control system described below. An additional shaft 120 with sprocket 118 drives via a gear 166 a further gear 168, which further gear operates a lever 162 of a switch 160, which operates the switch when rotating only in one direction (i.e. when the dancer rollers move away from the idler rollers). Web-roll support and brake Fig. 4.-Each web-roll is mounted on a collapsible spindle 179. The spindle 179 is supported at each end by a tubular chuck 176 fixed by a pin 180 to a head 182 formed at the inboard end of a horizontal shaft 184. A sleeve 190 is keyed as a sliding fit inside the chuck 176, and is rotatable in bearings 192 mounted in a barrel 194 fixed into a side plate 195 of the machine. A disc brake 198 is fixed to a hub 196, keyed to the sleeve 190 and retained thereon by a nut 200. The outboard end of the shaft 184 is fitted in a ball bearing 206 retained in an adapter socket 208 at the end of a screw 210. A guide finger 214 fixed to a plate 216, engages a slotted ring 212 retaining the socket 208, and thereby prevents rotation of the socket and screw 210. A nut 218 in threaded engagement with the screw 210 is rotatable in a bearing 220 by means of a hand wheel 222 to cause axial movement of the shaft 184 and chuck 176 to align the web-roll. Control Figs. 3 and 4.-The disc brake 198 is pneumatically operated under the control of the dancer roller assembly, and in this respect works whether a single, double or triple roller configuration is used. During the first twothirds of movement of the dancer rollers away from the idler rollers, and in response to such movement pressure pulses are applied to the supply-roll brake as a result of the operation of the switch 160. When the dancer rollers reach the final third of their movement away from the idler rollers, cam 146 opens switch 150, which is in the circuit of switch 160 (Fig. 12), thereby terminating the pressure pulses. The number of pulses for a given length of travel of the dancer rollers is variable by varying the ratio of change gears 164 and 166. An adjustable time delay relay (T.D3, Fig. 12) is provided in the pressure pulsing circuit to the brakes which enables the duration of each pulse to be varied. Pressure pulses are only applied to the supply-roll brake, when the supply-roll is delivering a greater quantity of web to the accumulator 30, than is being consumed by the machine being fed. During the final third of movement of the dancer rollers, a variable continuous pneumatic pressure is applied to the supply-roll brake under the control of cam 140 operating a pressure valve 298. The splicing cycle may be initiated either upon command or automatically as in Specification 1,136,951, with closure of either of switches (352 and 354, Fig. 12), which continually sense the size of the roll of unwinding web. A pilot light (348) is provided to signal that the apparatus is ready for the performance of a splicing operation, by manually closing a switch (340) when, for example, the new web-roll is in position and the preparations are complete.