Patent GB-1377398-A (GB)
Title: Ammunition and a method and arrangement for controlling the firing  of such ammunition from a weapon
IPC: F41A19/58
Filed: 1971-11-29
Abstract: 1377398 Determining the type and condition of ammunition; method of sighting RHEINMETALL GmbH 29 Nov 1971 [4 Dec 1970 4 Nov 1971] 55266/71 Headings F3A and F3C A method in which the type of ammunition and the temperature of its propellant charge is determined whilst the ammunition is in a weapon, comprises feeding an electrical signal into the round and producing an output signal which is characteristic of the type and temperature. The information is combined in a computer with information about the target and firing conditions and is used to position the weapon and/or set a fuze in a projectile forming part of the ammunition. In the embodiment, a positive signal is supplied from the computer 18 and fed to the input I of a change-over switch 20 and thence through output III and contacts 17 and 16 to circuitry in the ammunition. As a capacitor 8a in the ammunition charges up, so the current flow back to the computer steadily increases. After a predetermined time the return flow is measured by a device 27 and this identifies the ammunition, since the capacitor 8a is chosen according to the type. A resistance and/or inductance may be used instead of the capacitor 8a to similar effect. When the capacitor is fully charged, the return flow to the computer levels off. This is measured by a device 28 and determines the temperature of the propellant powder, since the flow is dependent upon an element 9 whose resistance varies in accordance with the temperature of the surrounding propellant. When the switch 20 is changed over to input II, a negative signal is fed from'a device 45 and activates the projectile fuze 15. This signal comprises a series of negative pulses which are counted by the fuze 15 or timed negative voltage signals which charge the fuze 15. Signals from devices 27 and 28 are fed into the computer 18 together with firing condition data from device 26 and target data from device 25. The computed signal is fed to the laying mechanism 22 of the weapon. The signal is also translated into a number of positive pulses in a pulse transmitter 32, or positive voltage signals, which are fed through an AND gate 31 and input II into the ammunition circuitry. The switch 20 is arranged to oscillate between inputs I and II so that these pulses or signals cancel those from device 40 and the setting of fuze 15 is thereby not influenced. However, on pressing a firing button 21, the positive pulses or voltage signals from the computer are diverted through the AND gate 31 to a voltage amplifier 29. The amplified pulses or signals pass into the ammunition circuitry where a four layer diode 11 now allows the current to pass through an igniter 12. The pulses or signals are also received by the fuze 15 and give the final setting as the propellant is being ignited. When the projectile ceases to accelerate, a switch is closed in the fuze circuitry and a generator in the fuze supplies pulses or voltage signals, which are added to, or increase the charge, supplied at the time of final setting. Thus a predetermined time after firing a proximity fuze is activated or the projectile is exploded. If the AND gate 31 is omitted the fuze is continuously set until the moment of firing. Where an impact fuze is employed, it may be activated by closing a switch, activating a power source such as a battery, or supplying a charging voltage.