Patent GB-318132-A (GB)
Title: Improvements in or relating to web tension controlling mechanism
IPC: B65H23/06
Filed: 1929-06-01
Abstract: 318,132. Goss Printing Press Co., (Assignees of Crafts, C. S.). Aug. 28, 1928, [Convention date]. Feeding webs.-Apparatus for controlling the tension of a web being fed to a printing or other machine comprises a web-engaging brake-controlling device moved by the tension of the web, and tension means acting on the web-engaging device against the tension of the web and adapted to be adjusted for web rolls of various widths. In one form, Fig. 1, a single web-engaging roller 82 serves to control the brakes of two rolls a, b. mounted on opposite sides of the frame 1, one roll being the active roll and the other a reserve roll. Each brake comprises a pair of vertical brake levers 24, 25 connected at their lower ends by pivots 26, 27 to bell-crank levers 28, 29 mounted by pivots 30, 31 on a block 32 laterally adjustable by a screw 136 and hand-wheel 139 for transverse register of the web roll. The levers 24, 25 can be opened out at their upper ends to receive the web-roll shafts 9 and brake drums 12, and are then connected by a pivoted bolt 39 whereby the normal brake pressure may be adjusted. The bell-crank levers 28, 29 are connected by a pin-and-slot connection 34 and an extension 35 of the lever 29 is connected by a link 55 to a bell-crank lever 58 having a pin-andslot connection 64 with the lower end of a rod 63, the upper end of which is connected to one arm of a bell-crank lever 70 fixed to a shaft 77. The other arm 79 of the lever 70 and a similar arm 84, Fig. 2, on the other end of the shaft 77 are provided with slotted ends 80 to engage the pintles of the web-engaging roller 82, which is mounted in slidable bearings 88. The roller 82 is held in contact with the web by a spring 101, Fig. 2, the ends of which are secured to a collar 99 fast on the shaft 77 and a worm-wheel 104 loose on the shaft 77 and operable by a worm 105, bevel gearing 108, 109, and a hand-wheel 112 to vary the tension of the spring as desired. The spring is of such a length that its tension remains substantially constant throughout the whole range of movement of the roller 82. Between the supply roll and the roller 82, the web passes round a guide roller 118 adjustable to compensate for differences of tension transversely of the web. For this purpose o.ne end of the roller can rock in its bearing while the other end is mounted in a sliding bearing 124 adjustable by a screw 127. In another form a separate webengaging roller is provided in connection with each roll a and b so that if desired two webs can be fed simultaneously and means are provided for connecting either web-engaging roller to both brake mechanisms if a single active roll only is employed. For this purpose each bell-crank lever 58 is connected to a rod such as 63 for independent operation and either rod can be disconnected from its bell-crank lever and the bellcrank levers connected together for simultaneous operation by the other rod. In another form. Fig. 7, both rolls are mounted on the same side of the frame 1, and their brakes are controlled by a single web-engaging rollers 82 through link and lever connections 177, 170, 168, 164, 161. The roller 82 is held in contact with the web by a spring arranged upon the shaft 171 of the bellcrank lever 170 and adjustable by a worm and worm-wheel in a similar manner to that of the opening 101, Fig. 2. The guide roller 205 is mounted in slidable bearings 206 independently adjustable by bolts 209 and nuts 210 to compensate for variations of tension laterally of the web. Fig. 11 shows a modified form of spring for holding the roller 82 in contact with the web. A strap 261, secured to and wrapped round the shaft 171 of the bell-crank lever 170, is connected to a U-shaped member 267 having hooked ends engaging the lower end of a spring 269. A second similar U-shaped member 273 engages the upper end of the spring and is carried by a screw 276 connected by a hand-nut 277 to a screwed rod 278 longitudinally adjustable in a guide 280 by a nut 281 and preferablycarrying a pointer 283 movable over a scale 284 preferably marked to indicate the tension for rods of different widths.