GB684765A - Improvements in and relating to paper reel joining mechanism - Google Patents

Abstract

684,765. Feeding webs. WITTON-JAMES, Ltd., BRADSHAW, R., TAYLOR, H., and RALPH, F. W. Jan. 18, 1951, [Oct. 18, 1949], No. 26763/49. Class 100 (i). Reel-joining mechanism to effect a join between a web-running into a printing press and the web of a replacement roll, comprises two electric generators responsive respectively to the speeds of the press and the expiring roll, each generator producing an output function, such as a voltage or frequency, varying with the generator speed and applied in opposition to control the operation of a member, or two members adapted to operate sequentially, thus initiating an operation required to effect reeljoining, or initiating two such operations in sequence. As shown, a D.C. generator P, driven at a substantially constant speed from a printing press, excites one coil of a pair of differential relays A, B connected across the generator terminals through potentiometers Pa, Pb. Similarly, a generator R, driven by the expiring roll, excites the other coils of the relays operating in opposition to the first coils through potentiometers Ra, Rb. During expiration of the reel being fed to the press, the voltage produced by the generator P is higher than that produced by the generator R, such that the relays are inoperative until the speed of the generator R so increases as to cause, through the increased voltage, the reversal of one of the relays, thus causing its contacts to initiate the preliminary stages of a reel-joining operation, i.e., the contacts cause rotation of a reel-carrier to bring the replacement reel into reel-joining position, and cause acceleration of this reel, e.g., by driving belts. When the expiring reel has been accelerated, the further increase in speed of generator R causes the reversal of the second relay B, the contacts of which then automatically initiate operations for the completion of the reel-joining operations, i.e., contacting the expiring web with the replacement reel which carries adhesive, such that it is fed into the press with the expiring web which is then severed. In a modification, A.C. generators replace the D.C. generators, their outputs being separately rectified to operate the relays directly or indirectly through thermionic valves which in this case operate electro-magnetic relays. In a further modification, the outputs of each of a pair of A.C. generators provides a variable frequency converted into a varying A.C. voltage by a reactance, such voltage being applied, preferably after rectification, directly to a relay or indirectly through a thermionic valve operating a relay.