GB334514A - Improvements in or relating to web supplying and controlling mechanism - Google Patents

Abstract

334,514. Jackson, L. Mellersh-, (Goss Printing Press Co.). June 1, 1929. Feeding webs. - In a web-supporting mechanism for a printing or other machine comprising a brake mechanism for the web roll and means controlled by the web for automatically controlling the brake, means are provided for attaching an expiring web to a new web roll without disturbing the continuity of the brake control bv the web, such means comprising a roller at each side of the running web adapted to be moved alternately to bring the web into contact with a new roll, means being provided to guide the inactive roller during the attaching operation. As shown in Fig. 1, two brake mechanisms in connection with a pair of rolls a, b are controlled by a single web-engaging roller 93. Each brake comprises a pair of levers 20, 21 mounted on trunnions 34, 36 and pivoted at their rear ends on separate pivots 22, 23 to an angular link 24. A bar 26 pivoted at its ends to the links 24 is centrally pivoted to one arm 75 of a bell-crank lever, the other arm 76 of which is connected by a rod 78 to a bell-crank lever 80 fixed to a cross shaft 81. The web-engaging roller 93 is mounted in bearings 89 slidable in guides 91, and the ends of its shaft 8S are connected by links 87 to an arm 85 of the bell-crank lever 80 and to a similar arm secured to the opposite end of the shaft 81. The roller 93 is urged towards the web by a spring on the shaft 81, one end of the spring being fixed to a collar on the shaft and the other end to a worm-wheel 108 loose on the shaft 81 and meshing with a worm 109 on a, shaft provided with a hand-wheel 113 bv which the normal spring tension may be adjusted. The spring is of such a length that its tension remains substantially constant throughout the range of movement of the roller 93. Stops 97 to limit the onward movement of this roller and springs 116 to cushion its inward movement upon starting the machine are provided. Before reaching the roller 93, the web passes round a guide roller 123 mounted in slidable bearings 124, one or both of which is adjustable by a screw 131 to compensate for variation of tension laterally of the web. The trunnions 34, 36 of the brake levers are bored and threaded to receive a right-and-left hand screw 38 rotatable in a central support 43 bv means of a hand-wheel 39 so that the brake levers may be opened out to allow of the removal of an exhausted roll together with its brake pulley 15 and the insertion of the new roll. The support 43 is provided with front projections 50 embracing the pulley 15 and is laterally movable on a guide rod 49 by means of a screw 54 and handwheel 57 for side register of the web, and to allow of the lateral movement of the links 24, the lower ends of these links are forked to receive long pivot pins 25 which can slide freely through the bar 26. The means for attaching the expiring web to the new web roll comprises a pair of rollers 179, 185, one on each side of the web, mounted in the ends of bars 174 centrally pivoted to arms 172 secured to a rock-shaft 171 provided with an operating handle 191. The shafts of the roller 179, 185 engage inclined slots 163, 164 in fixed bracket 161. The parts are normally held in the position shown by a pin 194 passing through aligned holes in the handle 191 and machine frame. To effect the join, the pin 194 is removed and the handle 191 operated to swing the appropriate roller 179 or 185 downwards to engage the web and press it against the new roll which has previously been prepared with a line of paste at its leading edge and positioned with that edge slightly in advance of the position of contact of the roller with the roll. The pressure of the roller causes the roll to rotate and its web to be attached to the expiring web which is then severed.