GB341261A - Improvements in web controlling mechanism for printing and other machines - Google Patents

Abstract

341,261. Feeding webs. SMITH, E. J., 18, Whitefriars Street, Fleet Street, London. Jan. 10, 1930, No. 996. [Class 100 (i).] In a braking-device for the web rolls of printing and other machines, of the kind comprising friction belts engaging the roll periphery and a pilot roller engaging the web, for automatically controlling the belts to maintain a constant predetermined tension in the web, manually-operated means are provided for taking up the slack of the belts as the diameter of the roll decreases. As shown, applied to an apparatus for supporting an active roll 14 and a reserve roll 15, each roll is provided with a braking-device comprising a number of belts 32 secured at their lower ends to pivoted arms 34, the upward movement of which is limited by adjustable stops 38, and at their upper ends to pulleys 39 fixed to a shaft 40 mounted in arms 41 secured to a shaft 42 provided with an operating- handle 47. A pinion 44 on the end of the shaft 40 meshes with a segment 45 whereby upon turning the shaft 42, the pulleys 39 are rotated to wind up or release the belts as desired. The segments 45 are idly mounted on the shafts 42 and are connected by links 58 to one of a pair of arms 54 carrying a pilot roller 50 around which the web passes so that movement of the roller 50 due to varying web tension operates the segments 45 to adjust the belts 32 to restore the tension of the web to normal. The roller 50 is held against the web by a compression spring 59 and by a helical spring on the shaft 57 carrying the arms 54, one end of the helical spring being secured to a collar fixed on the shaft 57 and the other end being fixed to a worm wheel 63 loose on the shaft and rotatable by a worm 64 and hand-wheel 65 to vary the spring tension and thus the normal web tension. The rolls 14, 15 are carried by arms 10 secured to a cross-shaft which may be turned to raise and lower the arms for the insertion of the web rolls by a quadrant 20 on the shaft and a hand-operated worm 21. The arms are adjustable on the cross-shaft to suit rolls of different widths and the cross-shaft is adjustable axially for side register of the webs by a screw 27, rotatable in the machine frame and threaded into the end of the cross-shaft.