Ammunition and explosives – Cartridges – Case
Reexamination Certificate
1999-11-19
2001-06-19
Carone, Michael J. (Department: 3641)
Ammunition and explosives
Cartridges
Case
C102S469000, C102S470000, C102S472000
Reexamination Certificate
active
06247412
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a cartridge which is adapted to be fired from a large-caliber weapon and which has a cartridge case accommodating at least one electronic unit coupled by means of at least two electric connectors with an electronic evaluating and control apparatus of the weapon. At least one of the electric connectors is coupled with the electronic unit by means of a contact disposed in an electrically insulated manner in the metal cartridge case bottom.
In known cartridges of the above-outlined type a connection between the electronic evaluating and control apparatus (for example, a fire control equipment) and the electronic unit situated inside the cartridge case is effected via the primer housing disposed in an insulated manner in the case bottom and via the cartridge case bottom electrically connected with the grounded weapon barrel. The electronic unit in the cartridge case may be humidity and/or temperature sensors as well as memories in which data characterizing the ammunition type are stored.
It is a disadvantage of the above-outlined cartridges that an electric contacting of the primer housing and conducting current therethrough is relatively complex and often a secure contacting cannot be achieved. Further, an electromagnetic compatibility in view of the outwardly exposed bottom of the primer housing is, as a rule, not ensured.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved cartridge of the above-outlined type in which a simple and operationally safe contacting between the electronic evaluating and control apparatus and the electronic unit or units situated within the cartridge case is feasible.
This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, the electric contact assembly is combined with a cartridge to be fired from a weapon barrel. The cartridge has a cartridge case including a metal bottom having an externally exposed outer face; and an electronic unit disposed in the cartridge case. The electric contact assembly includes a first contact arrangement for establishing an electric connection between the electronic unit and an evaluating and control apparatus situated externally of the cartridge. The first contact arrangement includes a contact ring disposed in the case bottom and surrounds the longitudinal axis of the cartridge. The contact ring has an outer face which is approximately flush with the outer face of the case bottom. An insulation electrically insulates the contact ring from the case bottom. A second contact arrangement establishes an electric connection between the electronic unit and the evaluating and control apparatus. A switching arrangement is connected between the contact ring and the second contact arrangement for maintaining a low ohmic-resistance connection between the contact ring and the second contact arrangement as long as a voltage applied to the contact ring and/or a current flowing through the switching arrangement remains below a predetermined minimum magnitude.
The invention is essentially based on the principle that instead of providing an electric contact via the primer housing of the cartridge, a separate contact ring is utilized which is accessible from the outside. To ensure that in case of such a contact ring arrangement the electromagnetic compatibility of the cartridge is observed, in the cartridge case between the contact ring and a second electric connection (which, as a rule is the grounded cartridge case bottom) at least one switching element is disposed which provides for a low ohmic-resistance connection between the contact ring and the second electric connection in case the voltage applied to the contact ring and/or the current flowing through the switching element falls below a predetermined minimum magnitude. Such a switching element may be, for example, a PTC-resistor (a resistor having a positive temperature coefficient) or a Zener-diode.
As an alternative to the low ohmic-resistance connection between the contact ring and the second electric connection, in the cartridge case between the contact ring and the electronic units a switching device is arranged which is connected with a voltage monitoring circuit and which connects the contact ring with the electronic unit only if on the contact ring a minimum potential is present and/or if the voltage is present for a minimum duration.
According to a further feature of the invention, in the case bottom of the cartridge at least one magnetic field sensor is arranged which is connected with the switching device. The latter, in turn, is designed such that it connects the contact ring with the electronic unit only if the breechblock of the weapon is closed, that is, when the magnetic field sensor, because of the closing of the breechblock, has generated a corresponding control signal that is applied to the switching device.
It has been found advantageous to arrange the magnetic field sensor directly at the contact ring and the switching device in the cartridge case.
REFERENCES:
patent: 3009419 (1961-11-01), Clay, Jr. et al.
patent: 5421264 (1995-06-01), Petrick
patent: 6131519 (2000-10-01), Thiesen et al.
patent: 20 59 665 (1972-06-01), None
patent: 0729372 A1 (1955-05-01), None
Carone Michael J.
Kelemen Gabor J.
Semunegus Lulit
TZN Forschungs- und Entwicklungs-zentrum
Venable
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