Patent GB-763833-A (GB)
Title: Improvements in sheet separating and forwarding machines
Inventor: TEBBS GEORGE WILLIAM
IPC: B41L47/24
Filed: 1953-06-01
Abstract: 763,833. Feeding sheets; addressing machines. BACKHOUSE, H. T. Sept. 1, 1954 [June 1. 1953], No 15212/53. Classes 100(1) and 100(2) A sheet feeding machine for supplying sheets to an addressing machine comprises mechanism for separating sheets from a pile and forwarding the separated sheets to, or towards, the addressing machine, a driving member, a releasable clutch between the driving member and the sheet feeding mechanism and means operable by the printing movement of the addressing machine head to couple the clutch, so as to initiate operation of the mechanism and means operable automatically to uncouple the clutch to stop the mechanism after the completion of one cycle of separating and forwarding operations. As shown in Fig. 1 sheets are separated by mechanism 10 from a pile 12 and passed between rollers 260, 264 to a band conveyer 100. The separating mechanism may be described in Specification 763,831, the operating shaft 66 being rocked by connection to a rail 65 which is raised and lowered on bell crank levers 64, 96. The lever 64 is oscillated by a cam 62 acting through rod 63. The pile elevating means may be as described in Specification 763,832. The first conveyer feeds the sheets to a second conveyer 110 (described more fully in Specification 763,834) which passes the sheets into and away from the printing position. The addressing machine is of the kind in which successive impressions are taken from printing plates or stencils by means of a rising and falling presser head 112, the plate being changed after each impres sion or after two or three impressions. Certain of the printing plates may be "skipped" i.e. although all plates are brought to the printing position, the presser head only descends to print from selected ones, and does not descend in the case of a "skipped" plate. Sheet conveyers:- The first conveyer 100 (see Fig. 2) comprises a number of tapes passing over rollers 260, 102, the upper laps of the tapes' run over the upper surface of the table 111 and sheets are pressed against them by wheels 101. Roller 102 is connected by chain 231 to a sprocket 230 on a shaft.60 driven through the clutch and gear mechanism described below. The second conveyer extends over the table 111 and overlaps the first conveyer. It consists of two rear pulleys 114 (Fig. 1) adjustable transversely along an oscillatable shaft 113 to suit different paper widths.. Two front pulleys 118 are aligned with pulleys 114. Attached to each of the pulleys 114 are two lengths of flexible steel tape 119, 120 which are laterally separated and extend round the pulley in opposite directions. The tape 119 passes closely over the table and is attached to the corresponding pulley 118. The tape 120 passes under jockey pulleys 122, 125, so as to pass close to the table lying alongside tape 119 and is connected to pulley 118. Both tapes carry several downwardly and forwardly directed hooks which are adjustable along the tapes and rub over the surface of the table. The backs of the hooks are chamfered so that in the return movement they can ride over the edge of the sheet under the tapes. The shaft 113 carries a small gear wheel 129 meshing with a larger wheel 130 carrying a radially directed fork 134. A bell-crank lever 136 pivoted on crossbar 123 carries a pin to engage in the fork. The'other arm of the lever 136 is connected by links 140, 141 to the arm of the presser head 112. As the arm descends, therefore, the pulleys 114 are rotated to cause hooks on tapes 119 to engage and advance the sheet to the printing position. As the arm rises the pulleys 114 are rotated in the opposite direction so that hooks on the tapes 120 engage and displace the sheet. According to the adjustment of the hooks the sheet may be fed into two or three printing positions before being delivered or it may be delivered after a single, impression. Control of first conveyer:- The shaft 60 driving the conveyer 100 is driven from a driving motor through a gear and clutch mechanism shown in Fig. 3. The driving motor is connected by chain gearing to a sprocket 206 keyed to a longitudinally slidable shaft 207. Three gear wheels 213, 214, 215, freely mounted on shaft 207, have key-ways 221, 222, 223 adapted to receive a key 220 resiliently, mounted in a slot in the shaft 207. Washers 225, 226 surrounding shaft 207 have chamfered edges so that longitudinal displacement of the shaft forces the key into its. slot and allows it to engage in the key-way of any one of the gears. The shaft 207 is displaceable by a control lever 218. Each of the gears 213, 214, 215 meshes with a gear 227, 228, 229 secured to a toothed clutch member 243 rotatable on shaft 60. The gear ratio between the wheel pairs 213 and 227, 214 and 228, 215 and 229 is 1 : 1, 1 : 2, and 1 : 3 respectively. Movement of the shaft 207 therefore selects any one of these gear ratios. The other clutch member 244 is slidably keyed to the shaft 60 and has teeth engageable with the teeth of the driven part 243. Movement of member 244 is controlled by a lever 242 spring loaded to the coupling position. A link 240 connected to lever 242 has a notch 239 engageable by a pin 238, on a lever 237 which is displaced in an anticlockwise direction, at a certain angular position of shaft 60, by a cam 235 mounted on the shaft 60. The cam thereby causes the clutch to be disengaged at the completion of each rotation of shaft 60. One rotation of shaft 60 displaces .the conveyer 100 an amount sufficient to feed a sheet to the second conveyer 110. The operating cycle of shaft 60 is initiated by a lever 246 (Fig. 1) which is rotated by downward displacement of the presser head 113 to trip the link 240 out of engagement with the pin 238 so that the clutch is allowed to couple and drive the conveyer 100. When two or three impressions are to be printed on each'sheet the gear ratio 1 : 2 or 1 : 3 is selected by lever 218. This provides that the second and third downward movement of the presser head do not cause the conveyer to make further operating cycles to feed a second and third sheet as. would occur with a 1 : 1 ratio. The sheet separating mechanism is actuated by cam 62 on shaft 60 and the suction and air pressure are controlled by valves driven from a sprocket 251 on shaft 60 so that the whole sheet separating and forwarding mechanism is geared to run at half or third speed by movement of lever 218. The lever 246 which initiates the feeding cycle of conveyer 100 is pivoted at 247, Fig. 1 and has a follower engaging cam 248 rotatable by lever 249 connected by link 141 to the presser head 112. Each time or each second or third time the presser head descends a fresh sheet is separated and forwarded to the conveyer 110 which, as described above is driven to advance it. on subsequent movement of the presser head. into and through the printing position. Faulty feed detectors:- If two or more sheets are fed at once to the conveyer 100 mechanism is provided for causing the link 270, Fig. 3, to be lowered into engagement with pin 238 so that the cam causes stoppage of the sheet feeding mechanism. The link 270 is normally supported out of contact with the pin 238 by the hooked end of a lever 262, Fig. 2 the other end of which acts as a detector. The lever has an arcuate end 261 fitting in a circumferential gap in roller 260. The presser roller 264 is adjustable so as to leave a gap over the end 261 of lever 262 which is more than one sheet's thickness but less than two. When two sheets are fed together they engage and rotate the lever 262, a wedging action of the surface 261 causing the grip on the sheets to increase. The lower hooked end 268 is thereby displaced from under the link 270 so that the link falls into a position of engagement with pin 238 and the clutch is uncoupled. The addressing machine is subsequently stopped by the normal nosheet trip. Stacking gauges for pile tables:- The lower pile support 22 is adapted to receive a pile board 26 upon which a pile of sheets for printing is built up and then advanced to the separating mechanism as described in Specification 763.832. To facilitate building up the pile, vertical stacking gauges 290, 291 project up through slots in the pile board. These gauges are adjustable horizontally as: shown in Fig. 4, being mounted on bars 293, 294 slidably mounted on transverse rods 295. Bars 293, 294 are connected by links 298, 299 to a lever rotatable to displace the bars by an operating handle 301. A rear stacking gauge 302 is independently adjustable along a fore and aft support 303.