GB840235A - Automatic electrical control system for flame-cutting machines - Google Patents

Abstract

840,235. Cutting by fusion. BRITISH OXYGEN CO. Ltd. Nov. 18, 1958 [Nov. 19, 1957], No. 36000/57. Class 83 (4). [Also in Group XXXVIII] In a flame-cutting machine of the kind in which the nozzle is guided over the work by a programme recorded on a magnetic tape, signals from the tape at the beginning of the programme stop the tape and initiate an automatic sequence of operations to position the burner and supply and ignite the gases, after which the tape is restarted to control the cutting of the prescribed shape, and at the end of the cutting process further signals shut down the burner and re-set the controls for the next cycle. Signals recorded on a tape 42 are read at 47, the X and Y co-ordinate signals for guiding the nozzle being represented by 48, 49. Before the X and Y signals are read however, signal 50 is read out to start up the ignition sequence, followed by a signal 50x-this and subsequent signals are represented in the drawing in time sequence-to stop the tape 42 until the ignition sequence is completed. Signal 50 energizes a relay 51 to apply a " down " signal to a motor 54 which advances the burner nozzle 53 towards the work 60 until a height sensing device (which controls the motor 54 to maintain the burner height constant) provides a signal 61 which together with a signal 62 from relay 51 actuate a summing relay 63 to energize solenoids 65, 66 to turn on the pre-heat gas, and after a short delay effected at 70 actuate the igniter 72. Relay 63 also starts a timer 88 which, unless the gases ignite to produce an output from a photo-cell 73, operates an alarm 90. Igniting the pre-heat gas produces a small output from the photo-cell 73 which after amplification in cascaded amplifiers 75, 78 is sufficient to operate a relay 79 which controls a preheat timer 81, and this, after a manually selected delay energizes some device 83 which in turn energizes solenoid 85 to turn on the oxygen and also energizes some device 45 to re-start the tape feed so that the cutting operation commences, provided the output of the photo-cell 73 has increased to indicate the presence of a cutting flame and so inhibit another timer 92 which would otherwise operate the alarm 90. Eventually a signal 99 is obtained from the reader 47 which controls some device 98 to lock the nozzle height-sensing device 52 and to switch off the photo-cell 73. The a signal 102 controls some device 103 to raise the nozzle 53 and cut off the pre-heat gas and oxygen, whilst a final signal 105 stops the tape.