Patent GB-1197147-A (GB)
Title: A Circuit for Automatically Operating the Breech of a Large Caliber Gun
IPC: F41A7/08
Filed: 1969-05-08
Abstract: 1,197,147. Control of D.C. motors. GENERAL MOTORS CORP. 8 May, 1969 [21 Aug., 1968], No. 23547/69. Heading H2J. [Also in Division F3] An automatic control circuit for a gun having a plug breech operable by a reversible D.C. motor receives signals from an automatic loader and from a fire control system in combination with signals indicating the condition of the breech, the recoil mechanism and the loader. Timed pulses are delivered to fire the round, the breech being opened automatically after the round has fired, or prevented from being opened if there is a misfire. Signals are fed back to the loader and fire control stations to indicate what has happened. To open the breech, an AND gate 10 receives a " breech closed " signal 310, an " in battery " signal 311 indicating that the gun has recoiled to the correct position, and a manual or auto. matic initiating signal through OR gate 17. The output signal from gate 10 inhibits a breechclosing AND gate 11 and is applied to OR gate 12 and to AND gate 14. The output signal from gate 12 is applied through delay circuit 13 to gate 14, and is also applied to a motor field relay and to a clutch solenoid. After a delay period, the gate 14 is opened to energize the motor armature through a controlled rectifier network. The breech is closed by supplying a "breech open " signal 313 and an initiating signal 314 to gate 1] ] whose output inhibits gate 10 through gate 18 and is applied to gates 12, 15. After a delay period, gate 12 opens to enable gate 15 and the motor is energized in the appropriate direction. For missile firing, AND gate 20 requires the presence of a " breech fully closed " signal 318, a signal 317 which indicates that the gun is in the battery positions and the pressure is normal, a signal 319 which indicates that the loader is clear as well as an initiating signal through OR gate 19. The output signal from gate 20 is applied to gate 21 which also receives a " missile loaded" signal 315 and a firing signal 320 through gate 30. The signal from gate 21 is applied to timer 22 which produces a pulse of maximum duration for firing the missile. Normally firing occurs earlier through timer 26, the timer 22 being stopped. If the missile does not fire the timer 22 repeats its cycle. Gate 23 energizes firing relay 31 to place an unregulated D.C. potential across a probe in the gun chamber. Gate 29 responds to extinguish the firing signal. Gate 24 is kept in its " on " mode to inhibit gate 10 and prevent opening of the breech while the gun contains a misfired missile. A signal 321 is produced when the gun recoils after firing and activates timer 26 which produced an indicative pulse. Gate 10 is then prepared for automatic opening of the breech. To fire a conventional round, the signals 318, 317 and 319 are applied to gate 20 and signal 316 is supplied through gate 19. Gate 33 responds to signal 322 and operates circuit 34 which produced a high direct voltage to burn off oxides from the case of the round. Gate 23 energizes relay 31 to place the potential of circuit 34 and an unregulated potential across the firing probe of the gun. The breech is prevented from opening if the gun misfires, the breech being opened in response to a recoil signal. The circuit 34 operates with an unregulated voltage source 37 connected across Zener diode 36 whereby constant base potential is provided for transistor 40 which is associatde with potentiometer 43. When transistor 40 becomes conductive, transistors 45, 46, are triggered to regulate the voltage between terminal 52 and earth. This regulated voltage is applied to the logic circuit elements throughout the system. When the load current through resistor 51 becomes excessive, transistors 61, 62, conduct to render the transistor 40 non-conductive. A high potential is provided between terminal 66 and earth by oscillator 69, 70, connected through a transformer to rectifier 74. Transistor 111 is controlled by a signal from AND gate 33. An output signal from AND gate 14 is applied to terminal 225 (5) to fire silicon controlled rectifiers 230, 231, and energize armature 233 for opening the breech. When the breech is fully open the AND gate 10 is disabled and the circuit is reset. A limit switch 209 prepares the breech closing circuit. The output signal from gate 12 is applied to motor field relay 195 and to a circuit for energizing the motor engaging solenoid 206. The various logic circuit components are described in detail in the Specification.