Patent GB-340945-A (GB)
Title: Improvements in web controlling mechanism for printing presses
IPC: B65H23/08
Filed: 1929-10-03
Abstract: 340,945. Feeding webs. HOE & CO. Ltd., R., 109, Borough Road, London, (Hoe & Co., Inc., 138th Street, New York, U.S.A.). Oct. 3, 1929, No. 30066. [Class 100 (i).] In a high-speed printing-press in which the web is fed to the press by draw-rollers 7, 8 and the running roll R, which is controlled by a friction band 6, is mounted together with a spare roll S in supporting arms 1 carried by a shaft 2, an electrically controlled arrangement is provided for moving the arms 1 in a direction opposite to the run of the web upon sudden stoppage of the press so as to take up any web which may unwind from the running roll due to its momentum. The electrical connections for the driving-motor 20 of the press, and for a motor 12 which is geared by worm-gearing to the shaft 2 and effects the required movements of the arms 1, is shown diagrammatically in Fig. 7. The motor 20 is controlled by a switch 21, which, when closed, operates by a relay 23 to bring a rheostat 29 into the circuit of the motor 20 which includes a series field 30 and a shunt field 31 in continuous connection with the lines 22, 25. The energization of the relay 23 opens a switch 23<1>. When the switch 21 is opened by hand or automatically to stop the printing-press, the relay 23 is de-energized and the switch 23<1> causes the closing of a circuit to the motor 12 for a short period. This is effected by the energization of a relay coil 33 by the brake current generated in the motor 20 by the shunt field 31. The relay 33 closes a switch which energizes a relay 35, and upon energization of this relay 35 the circuit to motor 12 is completed through the contacts 351 of a switch, this circuit including resistances 42, 40, and the lower contacts 39<1> of a relay switch 38. The circuit to the motor 12 is automatically opened as soon as the main press motor 20 has come to rest with consequent de-energization of the relay 33. The closing of the circuit to motor 20 to re-start the press causes the motor 12 to be driven in a reverse direction to restore the roll R to the normal position shown in Fig. 1. This is effected by the energization of a relay 37 via a switch arm 26 and contact 38. The relay 37 closes an energizing circuit for a relay 39 and closes its upper contacts 39<11> thereby reversing the How of current in motor 12. This current continues to flow until a limit switch 36 is opened by the shoulder 45<1> of a cam on the shaft 2 when the arms 1 have returned to normal position. To enable the arms 1 to be rotated under the control of the operator for loading a new roll or pasting a new roll to an expiring roll, push buttons 46, 47 are provided to control the circuits to the relays 39, and 35 manually. Safety switches 34 are included in the circuit of the relay 33, and these are controlled by cams 82, Fig. 5, on the shafts of spur wheels 79 which operate racks 80 controlling the cones 9 for supporting the rolls. The switches 34 are automatically opened when the cones 9 are withdrawn to release a roll. The shafts of the wheels 79 are operated by crank-arms 75 normally locked by spring-plungers which are released when spring- handles 11 on the crank-arms are gripped.