GB297219A - Improvements in web tension controlling mechanism for printing machines - Google Patents

Abstract

297,219. Hoe & Co., Ltd., R., (Hoe & Co., Inc., R.). Sept. 21, 1927. Peeding webs.-Means for controlling the tension of a web fed to a printing-machine consists of a friction device in the form of a strap or straps engaging the surface of the web roll and connected to a weight or other energy storing device supported by the running web, so that variations in the tension of the running web cause adjustment of the braking effect of the strap on the web roll. Means such as counterbalance weights may be provided for varying the pressure of the strap on the roll. In the construction shown in Fig. 1, the web 11 from the roller 10 passes over fixed guide rollers 12, 14<1> and an adjustable tension roller 15 mounted on springs 20, and is looped at 32 to support a floating roller 31 mounted m bearing blocks 34 carried by a pair of chains 29, the other ends of which are attached to a floating cross-bar 28. A narrow strap 23 is attached at one end to the cross-bar 28 and at the other end to a fixed bar 24, and passes over guide rollers 25, 26 so that it laps over about half the circumference of a full roll. Counterbalance weights 46 are connected to the chains. The bearing blocks 34 may slide on vertical guide rods 35. The chains pass over sprockets on a shaft 42, which may be provided with means, such as a hand-wheel and a detent pawl 49 and ratchet-wheel 48, for rotating it to raise the roller 31 and slacken the strap when a new roll is being placed in position. In another construction, shown in Fig. 6, three narrow straps 51 are attached at the lower end through springs 55 to a fixed bar 54, and are wound at the upper end op drums on a shaft 57 connected by chain gearing 59 to an upper shaft 79, over which and a lower shaft 72 run endless chains 65 carrying the floating roller 73 and the counterweights 69. The shaft 79 may have a squared end to receive a handle for rotation to slacken the straps.