Patent GB-476502-A (GB)
Title: Improvements in sheet feeder machines
IPC: B65H1/14
Filed: 1936-06-09
Abstract: 476,502. Feeding sheets. CROWN CORK & SEAL CO., Inc. June 9, 1936, No. 16142. Convention date, June 10, 1935. [Classes 100 (i) and 100 (ii)] In a sheet-feeding apparatus for feeding sheets from a stack and forwarding them to a printing or like machine of the kind in which suction separators and forwarders are used in connection with an automatically raised stack and the separation of the sheets is assisted by air blasts, improvements are effected in the means for controlling the movements of the stack. The mechanism for lifting the stack is operable by a power drive including a shaft which can be driven alternatively in step-bystep or continuous rotation, and by electromagnetic means the step-by-step drive is automatically disconnected upon starting the continuous drive. Parts of the machine disclosed are covered by other Specifications, namely, 476,503, 476,522, 476,526. The pile of sheets 51a, Figs. 1 and 2, is placed upon a platform or skid 50 formed with legs 98 by means of which the pile may be moved to a position in which the skid may be engaged by a pair of cross-bars 52 fitted with hook members 99 of double form, the upper hooks 99 being engaged by the cross-pins of freely hanging endless chains 53 which depend from sprocket gears 90 against which the chains are held by rollers 93. The use of double hooks prevents damage to the pile in case of breakage of the upper hooks, the pile being then supported by the lower hooks. To ensure side registry of the sheets a bend-end crow-bar 105 is inserted in one notch 104 of a plate 103 attached to a cross-bar 52 and the skid 50 is moved to the left against a gauge bar 106. The pile is so placed on the skid that the edges of the sheets extend over the left-hand edge of the skid, and when the sheets contact with the gauge, the inner ends of the chains 53 are inclined slightly to the right, and in their upward movement tend to hold the pile against the gauge 106. A second skid 50a can be positioned between the chains 53 before the pile on skid 50 has been exhausted. The shafts 54 for operating the sprockets 90 may be driven at a rapid rate from a motor 72, Fig. 26, by means of a magnetic clutch 74 which causes the motor to drive a shaft 380 geared to the shafts 54. The motor 72 also operates a suction pump 71 and a compressed air pump 70, and in the diagrammatic view, Fig. 26, the arrangement of electric circuits is shown in connection with the valve arrangements 73 for controlling the air pressures. Switches marked " up " or " down " on a control 480 are provided for causing the motor 72 to raise or lower the pile bodily and a limit switch 110, Figs. 2 and 26, is provided for stopping the motor 72 automatically should the operator fail to actuate the " stop " switch. When the magnetic clutch 74 is thrown in, the means for raising the pile automatically as the sheets are fed off is thrown out of action by the energization of an electromagnet 448 which causes a hold-out member 440, Fig. 25, to prevent a pawl 229 from engaging a ratchet 226 on a shaft 228 which is geared to the shaft 54. The pawl 229 normally controls the automatic raising of the pile during the feeding of the sheets, and the pawl is operated by a swinging carrier 232 operated from the main cam-shaft 56, Fig. 1, which controls the operation of most of the feeding operations. A hold-out member 224 allows the pawl 229 to operate except when the pile is sufficiently high not to need raising. This is determined by the motion of bars 173 carrying the suction cups 172 which act on the front of the pile. If either of the cups 172 descend far enough for a projection 173a to engage a disc 211, Fig. 25, on a spring-raised member 63, the member 63 is depressed and acts via levers 214, 219, shaft 218, lever 222 and link 223 to move the member 224 about a pivot at rightangles to the shaft 228, and thus allow the pawl 229 to operate. The separation of the top sheet from the pile is effected by the combined action of two suction separators 59 which act on the outer corners of the sheet and bend the edges of the sheet in a diagonal direction, and two air blast devices 140 which blow air under the top sheet when the corners are bent. Each separator comprises a suction cup 132, Figs. 1 and 17, connected by a pipe 135 to the valve 73 and mounted in a lever 126 which is pivoted to a second lever 128 by means of a pivot pin 129 which is formed with a bent extension provided with a roller 131, the periphery of which is parallel to the side edges of the sheets. The levers 126 are operated by a central dished cam on a shaft 118, Fig. 2, driven from the main cam-shaft 56, and the cups 132 are first raised from the pile by movement of the levers 126 about the pins 129, and then abutments on the levers 126 actuate the levers 128 and the rollers 131 engage the upturned portions of the sheet and produce outward bends in the turned-up corners as indicated in Fig. 17, thus tending to force back the edges of a lower sheet should double feed occur. The levers 126 are moved towards the pile by gravity. The sheets are forwarded from the pile by suction cups 172, Figs. 2 and 18, each of which is carried by a rod 173 supported from a reciprocating carriage 157 by means of parallel links 174, 175. The carriage 157 is connected by an adjustable link to a lever 160 oscillated by a cam 162 on the shaft 56 and controlled by a compression spring 165. The rising and falling movements of each cup 172 are controlled by a cam bar 178 engaging a roller 177 on the lever link 174. From the cups 172 the sheets are taken by forwarding rollers 66, 64, the lower rollers 64 being positively driven and the upper rollers being mounted in oscillating levers 265 operated by a cam 267 on the shaft 56. While passing over the rollers 64 the sheets are operated upon by calipering mechanism which permits single sheets to be advanced to the printing machine by means of driven feed rollers 253, Fig. 8, with which co-operate fixed sheet guides and hold-down rollers 272 mounted in brackets 269 as shown in Fig. 8. The calipering mechanism causes double sheets to be acted on by a reject member 68 to direct the sheets to a shelf formed of bars 243, but if more than two sheets are engaged by the calipering mechanism a clutch is operated to stop the actuation of the feeding mechanism. The calipering device is described in connection with Specification 476,523. The clutch-operating shaft 276 may be operated by a hand-lever, and when the clutch is disengaged the cam-shaft 56 may be turned by means of hand wheels at either end of the shaft. As shown in Fig. 26, the suction pump 71 and the pressure pump 70 are driven by a motor 72, and the outlet of the suction pump is connected to the inlet of the pressure pump 70. The outlet of the pressure pump is connected to a pressure tank 389 mounted above the pumps and below the valve 73 to which the inlet of the suction pump is connected. This arrangement ensures that any oil forced by pump 70 into the tank will settle in the bottom of the tank, and not reach the valve casing. Oil collecting in the tank may be returned by a pipe 391 and valve 391a to the suction pump, and thence into the pressure pump, thus keeping both pumps lubricated. The tank 389 is provided with cooling fins 389a. The valve mechanism comprises a series of spring-pressed poppet valves actuated by cam-and-lever mechanism from cams on the shaft. 56. Specifications 476,524 and 476,525 also are referred to.