Patent GB-430752-A (GB)
Title: Improvements in or relating to web-threading devices for printing machines
IPC: B41F13/03
Filed: 1933-12-20
Abstract: 430,752. Feeding webs. LOUGEE, F. G., 109, Borough Road, London. Dec. 20, 1933, Nos. 35882/33 and 22462/34. [Class 100 (i)] In a printing-machine having a drive mechanism comprising a slow-speed motor and a fullspeed motor, the slow-speed motor being automatically rendered inoperative when the fullspeed motor commences to drive the machine, drive means are provided for a leading-in tape or the like which are responsive to the condition of the slow-speed motor so as to be rendered inoperative when the slow-speed motor is rendered inoperative. The endless lead-in tape or chain 17, Fig. 1, for the web 6 passes over pulleys some of which are mounted on, but freely rotatable relative to, the shafts of rollers over which the web passes; the axes of the pulleys 20, 22 are inclined so that the plane of the run of the tape as it passes round these pulleys is changed, and the pulleys are mounted on rods 31 adjustably carried by supports 32. The tape is driven from a pulley 30 by means of gearing from the slow-speed motor of the press so that when the main motor is started up and the slow-speed motor automatically stopped, the tape-drive is discontinued. Alternatively, fixed to the shaft of one of the driven rollers of the machine, e.g. one of the slitting-rollers, there may be provided one part of a cone clutch, the other part of which is formed integrally with a tape pulley freely rotatable relatively to the roller shaft. The first-mentioned part of the clutch may be caused to engage the second part by the movement of a spring- pressed pivoted lever, the movement being produced by a solenoid against the action of the spring. The solenoid may be connected to the circuit of the slow-speed motor so that when the latter is energized, the clutch is engaged and the tape pulley is driven. The solenoid may alternatively be energized by closing the main control switch and de-energized as before when the main motor starts to drive ; and it remains de-energized at all times except when starting up the press or if desired when the slow-speed motor is operative and the press speed is reduced to a predetermined low value. Such an arrangement is shown in Fig. 6, where the circuit of the clutch solenoid 53 is closed on closing the main switch 54 through a contactor 55, the solenoid 56 of which is energized on closing the switch 54 through a circuit which includes fingers 63, a stud 65, and a segment 61 of a drum controller 62, forming part of the main press controller which includes studs 66, segment 67, and fingers 68 for controlling the slow-speed motor. The contactor 55 is also provided with a contact 69, which completes the circuit of the solenoid 56 when the controller 62 is adjusted to speed up the press by moving the fingers 68 over the studs 66, which movement simultaneously moves the fingers 63 over the segments 61, 64, but maintains closed the circuit of the solenoid 56 and hence of the solenoid 53 until the latter fingers move clear of the segments 61, 64, at which point the main press motor takes charge and the fingers 68 are clear of the studs 66. The clutch solenoid 53 remains open until the fingers 63 re-engage the stud 65 and segment 61. The slitting-roller driving the tape is situated at the top of the machine and the web is fed from the bottom of the machine by the tensioned side of the tape. The guide pulleys may be replaced by polished steel plates having rollers incorporated therein to reduce friction. In a multi-unit machine a number of tapes is employed, and the solenoid for each tape is provided with a separate switch for interrupting any particular circuit.