GB441941A - Improvements relating to control systems for electrically actuated rolling mill screw-down gear - Google Patents

Abstract

441,941. Rolling. LANGLEY, E. H. M., 7, Grosvenor Road, Urmston, GEORGE, H. N., Rockford, Lonsdale Avenue, Davyhulme, both in Lancashire, and ASSOCIATED ELECTRICAL INDUSTRIES, Ltd., Crown House, Aldwych, London. Aug. 29, 1934, No. 24878. [Class 83 (iv)] [See also Group XXXVII] A motor, operating rolling mill feed or screwdown mechanism is under the control of a series of sequence relays R1-R13 adapted when actuated to cause screw down movement of the gear through predetermined amounts, the operating coils of alternate relays R1, R3 ... being associated with one control bus-bar 26 and those of the intervening relays with another control bus-bar 25, the said control bus-bars being automatically energized in turn by alternate passes of the material 13. A throw over switch 23 effective to cause the alternate energization of the control bus-bars is operated by means of a coil 22 controlled by a relay 18, 21 under the control of a light sensitive relay 16, 17 and is arranged to be actuated on alternate passes only. The circuit through the contacts of the throw-over switch is kept open until a complete pass of the material has been made, by means of normally closed contacts opened by energization of the coil 22 of the throw over switch. Energization of a sequence relay closes contacts in the circuit of the coil of the next relay in the sequence and trips the preceding relay. It also closes a corresponding motor contact M1, M2 ... which completes the circuit of a coil 28 closing the motor circuit for screw-down operation. The motor thus effects screw down adjustment and is stopped by means of a corresponding limit switch L1, L2 ... operated by corresponding cam member T1, T2 ... on a drum driven by the motor. The cam members T1, T2 ... are adjustable as to their angular positions on the drum. When the sequence of screw-down movements is completed and the contacts M13 are closed by the relay R13, a coil 30 is energized to connect the motor for reverse operation until a limit switch L13 is operated at the end of the screw-up movement. As the drum carrying the cam members makes several revolutions during the screw-down movement the contacts L13 are shunted by closed contacts 32 on a drum 34 geared to the main drum to make one revolution only, the contacts 32 being opened by a cam 33 only at the end of the screw-up movement. The relay 29 is energized to cause slow down prior to the completion of the screw-up movement by a switch N13 operated by a cam 36 on the main drum and a switch 35 operated by a cam on the drum 34. The relay R1 is set for a fresh screw-down operation by means of a relay R14, the contacts C14 being tripped out when a coil R19 in parallel with coil R1 is energized. A lamp 42 is arranged to indicate when the apparatus is reset for screw-down operations, the lamp circuit being controlled by a contact 44 operated by the main drum, and a contact 43 operated by the drum 34. If the sequence is to include screw-up movements selector switches P6 ... are arranged to connect the motor contacts M1, M2 .. to the contactor coil 30, as shown in the case of motor contacts M10.