Patent GB-757849-A (GB)
Title: Improvements in or relating to a sheet feeding machine
IPC: B65H9/14
Filed: 1954-08-09
Abstract: 757,849. Feeding sheets. HARRIS-SEYBOLD CO. Aug. 9,1954 [Aug. 10,1953], No. 23068/54. Class 100 (1). In apparatus for feeding sheets to a printing or other machine a preliminary advancing means feeds the sheets to a reciprocating carriage adapted, for a given distance, to carry the sheets forward at a constant speed equal to that of the printing &c. machine, the carriage having back gauge abutments, which take sheets from the preliminary means, and a pair of side gauges, and means is provided for moving inwardly at least one of the side gauges to gauging position during their forward travel. The apparatus is shown as applied to an offset printing machine for printing on metal sheets S which are separated from a pile, fed forward by abutments 22, Fig. 22, on belts 20, then by abutments 23 on belts 21 at a higher speed which is less than printing speed, and finally by abutments 102 on a reciprocating carriage which first accelerate the speed of the sheets to printing speed, and continue at this speed until the sheets are taken by grippers 34, Fig. 1, on the impression cylinder 32. The abutments 102 are independently adjustable transversely and in the direction of that feed to act as rear registration stops, and swing upwardly to feed the sheets along a table 24, and downwardly below the table on the return stroke of the carriage. The sheets can, however, be front registered by stops on the grippers 34 in which case these grippers close earlier than with back registration. Magnetic rollers 217, Fig. 2, may be used to hold the front ends of the sheets against the table 24. The carriage comprises side racks 42, 43, with teeth on their under sides, rigidly connected by cross rods 44. Guiding rollers 45 on the racks engage inclined guide bars 40, and the rack teeth mesh with pinions 50-52 on a shaft 49 which is oscillated through equal arcs backward and forward for each machine cycle. Double pinions are provided to eliminate backlash. The carriage also comprises two side brackets, such as 94, joined by tubular rods 96, 97, and this structure can be adjusted forward and backward on the racks by pinions 99, Figs. 1 and 2, on a shaft passing through the tube 97, which engage rack teeth cut in the upper faces of the racks. This allows sheets of different lengths to be accommodated since the abutments 102 are mounted on the tubes. Each abutment or back gauge 102, Figs. 2 and 15, is bolted to a block 103 adjustable by screw, nut, and stop means 105, 108, 106 on an arm 104 in the direction of sheet feed. The arm 104 is loosely mounted on the rod 96, and can be swung thereabout by a pivoted lever 116 acting through a rod 114 and spring 119. In the position shown, the spring urges a head 109 against a stop 110 on an arm 111 fixed on a bracket 112 mounted for transverse adjustment on the tubular rods 96, 97; if the sheets S are to be front registered by the grippers 34, the stop 110 can swing away since it is mounted on a rod 121 and held in adjusted positions by a spring 122 and nuts 123, 124. The lever 116 has rollers at the other end engaging in a track 75, Fig. 1, which is raised bodily periodically by lever means operated from an angularly adjustable cam 56 on a shaft 55 which makes one revolution per machine cycle. Side gauges 140 are also operated from a second track 58, Fig. 1, which is raised bodily periodically by lever means operated from another angularly adjustable cam 57 on the shaft 55. Roller followers which engage the track are carried by a crank 138 which rocks a shaft 139 carried by the brackets 112 and further brackets 143 on the tubular rods 96, 97 of the carriage. The shaft 139 is adapted to rock the opposed side gauges 140 towards each other about pivots 165 on the brackets 143 through springs 161 on rods 155. The spring 161 on the right side gauge is stronger than that on the left, and when this gauge swings inwardly a stop thereon abuts a stationary adjustable stop on the bracket 143. The weaker spring on the left gauge allows this gauge to yield to accommodate sheets of uneven width. The side gauges are moved towards each other at about the same time as the back gauges 102 contact a sheet. Scales 215 on the brackets 94 and gauge lines 216 on the brackets 143 enable the side gauges to be adjusted. Sheet-engaging rollers 142 are provided on these gauges. The arrangement for reciprocating the sheet-feeding carriage includes double gears to prevent backlash, the drive being taken from the shaft 33 of the cylinder 32. The forward motion shaft 55, Fig. 2, is geared to the shaft 33 and is constantly driven at the same speed as the latter. A gear segment 184 on the shaft 55 engages a gear 185 on the reverse motion shaft 49 to drive the latter at times, and the gear 185 meshes at times with a gear segment 187 on a shaft 183. The shaft 55 has also keyed thereto a two-armed bracket 188 carrying rollers adapted at times to engage radial cam shoes on a bracket 194 secured to the shaft 49 ; a similar bracket 191 on the shaft 183 has rollers also adapted at times to engage the cam shoes on the bracket 194. By this arrangement of gear segments and interengaging rollers and cam shoes, the shaft 49 is rotated first in one direction and then in the other through equal arcs to drive the carriage. The forward motion is effected by the shaft 55 whereby the carriage is first accelerated to printing speed, kept at this speed for a period during which a sheet is advanced at least one-sixth of its length, then decelerated smoothly to zero speed; the return motion is effected by the shaft 183 and follows the same pattern. The sheets are guided by metal plates 178, Fig. 1, inclined laterally and curved upwardly, and secured to brackets 174 carried on posts on the adjustable brackets 143 of the reciprocating carriage.