Patent GB-348041-A (GB)
Title: Improvements in feeding paper webs from reels on printing machines
IPC: B65H19/16
Filed: 1929-10-28
Abstract: 348,041. Printing-machines. CRABTREE & SONS, Ltd., R. W., Water Lane, Leeds, PHYTHIAN, T. E., 25, Headingley Mount, Headingley, and ADKINS, F. S., Kylemore, Newall, Otley, both in Yorkshire. Oct. 28, 1929, No. 32740. [Class 100 (i).] Web-roll changing and braking devices.-In a webrenewing apparatus for a printing-press, the web rolls c, c are provided with dynamo-electric machines a<3>, a<3> adapted to be driven from a generator which is driven by the press so that a new roll may be rotated at a peripheral speed equal to that of the expiring web while the webs are being joined together. During the normal feed from a roll its dynamo-electric machine a<3> is driven by the roll as a generator with its armature in series with a fixed resistance so as to act as a brake. A variable resistance is arranged in circuit with the field of the generator a<3> of the active roll, and is automatically adjusted, upon variation of the tension of the web, by the movements of a floating roller k round which the web passes. The change of field resistance thus varies the braking effort of the generator to restore the tension of the web to normal. The movements of the roller k are communicated to the control spindle j<1> of the field resistance, through a selecting mechanism, such as that described in Specification 265,256, [Class 100 (i), Feeding and delivering webs &c.], which causes a gear i<4> to be turned in one or the other direction. This gear i<4> is connected through chain-and-bevel gearing to the member j<1>. Means may be provided for short-circuiting a part or the whole of the field resistance when the main inching-button of the press is closed. The means for joining the expiring web to a new roll comprises a pair of rollers b<3> carried by levers b<2> centrally pivoted to arms bl fixed to a shaft b adapted to be turned by worm gearing b<6>, b<7> and a hand-wheel b<10>. Pinions b<4> on the pivots of the levers b<2> engage fixed segments b<5> so that as the shaft b is turned, the arms b2 are also turned about their pivots and one of the rollers b<3> presses the web, which passes between the rollers b<3>, into contact with the new reel c. Prior to the turning of the shaft b a changeover switch is operated to close a circuit to cause the dynamo-electric machine a<3> of the new roll to be driven as a motor to speed up the new roll to the speed of the expiring web. This circuit includes a time-lagging device which acts automatically after a predetermined time to open the circuit so that the machine n<3> is thereafter driven by the roll as a generator. The change-over switch may be operated automatically by the closing of a circuit by means of a lever resting against the roll surface. Instead of turning the shaft b by hand, it may be operated by a reversible motor which is started by the operation of the change-over switch and stopped automatically by a limit or time switch. The arms bl may be loose on the shaft b and actuated therefrom through a spring connection so that the arms may yield when the roller v<3> engages the roll surface.