GB191512209A - Improvements relating to Rotary Printing Presses. - Google Patents

Abstract

12,209. Mascord, G. W. Aug. 24 Feeding webs.-Relates to apparatus for reducing the braking action on the web-roll spindle of a rotary printing-machine when the tension is excessive, the device being operable at will by mechanism deriving constant motion from the machine. The arms b, carrying the blocks a engaging the brake drum c, are carried by pivots b<1> supported from a bracket h, which is adjustable along guiderods f, f<1> by a screw i' mounted in the bracket and engaging a screwed boss i projecting from the machine frame, in accordance with the width of the reel. The upper pivot b<1> is mounted in a sleeve j slidably supported in the bracket h and embracing a screw k carrying a worm-wheel l. The screw k engages threads in the sleeve, or a threaded segment j<3> pivoted to the sleeve and normally held in engagement by a spring. When the web tension becomes excessive, a constantly rotating worm p is moved into engagement with the wheel l to rotate the screw k and move the upper pivot b' outwards to reduce the braking action. The worm is fixed on a spindle mounted in a forked bracket n freely pivoted on a preferably vertical shaft m adapted to serve similar mechanism on several decks, and is driven constantly by bevel-gears o, o<1> from the shaft m. The rocking movement of the bracket to engage and disengage the worm may be effected at will through an arm n<5> pivoted to a solenoid q, the energization of which is controlled from any desired position by hand. A spring buffer r acts against the bracket n to prevent damage to the worm when moving into engagement. The adjustment device described may be arranged between the outer ends of the arms b, and the usual adjustment by screws e engaging a right and left handed nut e<2> arranged at the middle pivots of the levers.