Patent GB-798702-A (GB)
Title: Improvements in or relating to apparatus for automatically controlling the operationof a punch tool machine
Inventor: ROBERTS TREVOR
IPC: G05B19/29
Filed: 1955-10-22
Abstract: 798,702. Programming for machine-tools. GENERAL ELECTRIC CO., Ltd. Oct. 22, 1956 [Oct. 21, 1955], No. 30182/55. Class 83 3). Apparatus for controlling a multi-tool punching-machine having at least one electric motor 19 for setting the machine prior to a punching-operation, comprises means 32 for storing data read from a flexible-tape, one or more digitizers 27 adapted to be set in accordance with the actual setting of the machine, and means 16 for controlling the motor(s) in dependence upon a comparison made between the setting of the digitizer(s) and the contents of the storage means. Two standard five-hole telegraph-tapes (or magnetic tapes or punched cards), carrying identical instructions, are fed to tape readers 1, 2. The initial information from tape-reader 1 is printed in plain language by a teleprinter 4, thus giving details to the operator, concerning, for instance, loading of the work and the repositioning of the work when some holes have been punched, and to provide a visual check that all the holes have been correctly coded on the tape. The succeeding information from both tapes is received by control circuits 5, 6 which convert the information into digits. The digital information is fed by uniselectors 7, 8 to storage units 31, 32, each having four self-motoring 12-position stepping switches, the digits being fed to the correct switches by uniselector contacts 11, 12 and a wiper 9, 10. Information is similarly fed to storage units 33, 35 and 34, 36. Comparator circuits 13-15 check at all times that corresponding storage units, e.g. 33, 34, contain identical information and operate an emergency tape-stop-control 29 if there is any discrepancy. Thus, the storage units 31, 33, 35 may control the press while the other units act as a monitoring system. (Alternatively, a single tape having a self-checking code could be used.) The work, such as a switchboard panel, is clamped on a mounting movable parallel to the front of the press, the mounting being carried by a trolley movable in a transverse direction. The mounting and trolley are moved by electric motors 19, 20. The direction and speed of the motor 19 is controlled by the comparator circuit 16 in accordance with a continuous automatic comparison between the actual position of the mounting recorded by the digitizer 27 on the motor shaft and the required position recorded by the storage unit 31. The digitizer comprises four rotary switches geared to the motor, each having a wiper, the position of which represents a digit. Thus the position of the mounting is represented by a four-digit number. As each wiper reaches its correct position, resistances are brought successively into circuit to slow the motor speed, the motor being stopped after a time delay has operated to ensure that the correct position has been reached, after which a brake is actuated. Similarly the motor 20 is controlled by a comparator circuit 17, the storage unit 33 and a digitizer 28. Thirty-two punches are contained in a rotary turret head rotated by a motor 21 having a two-switch digitizer, its setting being compared with the contents of the storage unit 35 by a comparator circuit 18. When the work and turret are correctly positioned, a control circuit 30 operates the tool. In operation, the operator, after reading the printed instructions, presses the start button 3 which causes the tapes to be fed and the mounting and trolley to be moved to their initial loading positions. When the switch is next pressed, after the work has been loaded, the machine operates automatically to punch a series of holes. An auxiliary store may be provided to read instructions from the tape while the punch is operating. When the last hole has been punched, the work is positioned for unloading and the tape readers are reversed to their positions obtaining prior to the punching of the first hole.