Ammunition and explosives – Projectiles – Target marking
Reexamination Certificate
1999-08-17
2001-08-14
Tudor, Harold J. (Department: 3641)
Ammunition and explosives
Projectiles
Target marking
C102S473000
Reexamination Certificate
active
06272998
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tracer sleeve having a self-destruction charge, for a projectile, and being adapted to be screwed into a threaded bore in the rearward end of the projectile. The self-destruction charge being situated in a recess in a forward bottom of the tracer sleeve.
2. Description of the Related Art
It is known to place a self-destructive charge in a separate sleeve or capsule, which is screwed into the forward end of a tracer sleeve. During launching of the projectile by use of a propellant charge, which acts against the rear end of the projectile, there is a danger that gases from the propellant charge may flow forwardly to the self-destruction charge, through the thread connection between the tracer sleeve and the projectile bushing. This brings about the danger that the self-destruction charge may be ignited, whereby the remaining charges in the projectile react and the projectile bursts. This will normally only happen if the projectile continues in its trajectory beyond a predetermined time, for instance when the projectile misses a target, whereby the development of heat in the tracer charge causes ignition of the self
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destruction charge.
SUMMARY OF THE INVENTION
With a tracer sleeve according to the invention, the possibility of unintentional ignition of the self-destruction charge caused by gases from the propellant charge flowing forwardly to the self-destruction charge is avoided.
According to the invention a bushing bottom in the projectile separates the bore from a more forwardly situated charge chamber, the recess being a blind bore from the forward of the bottom of the tracer sleeve, and the blind bore being closed by a disc which is sealingly attached in front of the blind bore. Thereby, it is not possible for gases developed by the propellant to pass along the threads connecting the tracer sleeve and the projectile bushing to enter the blind bore in which the self-destruction charge is situated. In order that the self-destruction charge may function in the normal manner, there is no need for forming a throughgoing hole in the bushing bottom ion front of the blind bore, because the bottom of the bushing in front of the blind bore is formed by a wall having such a strength that the wall bursts when the self-destruction charge is fired, whereby the charge may cause ignition of one or more main charges (incendiary and/or explosive charges) further forwardly in the projectile.
The invention also provides a solution for another problem related to projectiles which are stored for a long time. A tracer charge normally has a shorter maximum storagetime (10-15 years) than the remainder of, for instance a grenade (25-30 years). Thus, replacement of the tracer charge and a self-destruction charge may therefore be of interest for storing beyond these 10-15 years. When a tracer retainer according to conventional practice is in direct contact with a bursting charge in a projectile, unscrewing of the tracer retainer entails that the bursting charge is exposed. The bursting charge will usually have been pressed against the tracer retainer, because a tight contact of the bursting charge against the tracer retainer is essential in order to avoid “setback” due to inertia forces during launching. However, when a new tracer retainer is screwed in during replacement, the length of the retainer lies within certain tolerances, and there is a possibility that a slit is formed between the bursting charge and the new retainer. The projectile may, therefore, be dangerous to launch, because an adiabatic heating of the bursting charge may occur in the slit area. Measures for avoiding such a slit consist of placing discs (“shims”) for filling the slit, but this must be combined with X-ray checking in order to ascertain whether the slit is actually filled. Replacement of the tracer charge, therefore, is complicated.
The present invention discloses that a bursting charge in front of the tracer charge and the self-destruction charge is pressed in against a fixed bottom in the projectile bushing, and is thus not influenced by a replacement of the tracer charge.
The invention will be described in a more detailed manner in the following, with reference to the accompanying drawing, showing an example of an embodiment of the invention.
REFERENCES:
patent: 1518247 (1924-12-01), Brayton
patent: 2093353 (1937-09-01), Gertmann
patent: 2296901 (1942-09-01), Brayton
patent: 2530934 (1950-11-01), Barton et al.
patent: 3494285 (1970-02-01), Doris, Jr. et al.
patent: 3677181 (1972-07-01), Giljarhus et al.
patent: 4553482 (1985-11-01), Weber et al.
patent: 411381 (1934-06-01), None
patent: 6701593 (1967-08-01), None
Bacon & Thomas PLLC
Nammo Raufoss AS
Tudor Harold J.
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