Device On Weapon Barrels For Reduction Of The Angle Jump Of A Projectile

Abstract

A device on gun barrels for the reduction of the angle jump of a projectile, which comprises at least one reinforcement member fitted to the forward range of a gun barrel, and is adapted to dampen bending oscillations occuring upon firing in the gun barrel.

Description

The present invention relates to a device on weapon barrels for the reduction of the angle jump of a projectile.

During firing from a weapon barrel set at a predetermined angle of elevation, it is generally found that the projectile starts its flight path at the moment of passage of the muzzle at an angle which is different from the set angle. The angle difference between the angle of elevation and the angle of departure of the projectile is generally known for a long time as the angle jump. The reason for this angle change resides in the fact, that the gun barrel performs oscillations during the passage of the projectile, which impart a different position to the gun barrel at the moment of the departure of the projectile and a certain cross-speed in the direction of the deflection and perpendicular to the barrel-axis and core-axis, respectively.

It has been recognized, that the main-part of the angle jump of perfectly set barrels of guns, in particular of cannons, howitzers and mortars, i.e. the deviation between the target and the point of impact originates from high-frequency bending oscillations of the gun barrel, which precede the projectile. Due to these occurences, aside from disturbances of different causes, the projectile leaves the muzzle at an angle deviating slightly from the direction of the target and raising, respectively.

It is one object of the present invention to provide a device on weapon barrels for reduction of the angle jump of a projectile in which the angle jump, caused by a plurality of factors, of which the barrel-bending-oscillations assume the greatest part, is reduced, with the aim to obtain a greater target exactness.

Based on the physical laws concerning the oscillation-behavior of conic, one-sided clamped rods, which are excited with a high frequency at the clamped end perpendicularly to the cone axis, it can be deducted, that also the gun barrel is loaded at the most in the vicinity of the free end (thus in the vicinity of the muzzle). Depending upon the order of the excited bending oscillations also a plurality of such loading extremes can occur, which are disposed, however, always in the forward range of the barrel, thus in the vicinity of the muzzle.

Starting with this recognition, the solution of the present invention resides in the arrangement, according to which the gun barrel has in the forward longitudinal range a strutting which dampens the bending oscillations.

By the increase of the bending rigidity, which is defined by the formula:

B (X) = E J (X),

wherein

E is the elasticity-module

J (x) is the plane-moment of inertia per longitudinal unit,

The load and, thereby, the muzzle angle can be decisively reduced.

This is brought about by the increase of the value J (X), which is given by the formula:

J (X) = .pi./4 (R.sup.4 (X) - r.sup.4),

Wherein

R and r are the radii of the gun barrel within the range of the prevailing load.

Adventageously, the strutting is disposed in the vicinity of the muzzle and comprises a rotation-symmetrical body enlarging the plane-moment of inertia of the barrel in this range. The oscillations excited in the barrel upon firing are thereby dampened, still before the projectile has left the barrel, and in this manner the angle jump is reduced.

It is another object of the present invention to provide a device on weapon barrels for reduction of the angle jump of a projectile wherein, depending upon the type of the gun barrel, the strutting comprises a ring-reinforcement of the barrel wall of corresponding dimension or a metal-ring-member, which is connected with the barrel by fitting on the barrel and by shrinking the metal-ring-member on the barrel. In order to obtain the desired effect, it is of importance, that the connection between the strutting and the gun barrel is very intimate, that means that a mere screwing on of the strutting on the gun barrel has a lesser effect.

With these and other objects in view, which will become apparent in the following detailed description, the present invention, which is shown by example only, will be clearly understood in connection with the accompanying drawing, in which:

FIG. 1 discloses an elevation of the device constituting one embodiment of the device designed in accordance with the present invention; and

FIG. 2 is an elevation of the device constituting a second embodiment of the present invention.

The device of the present invention comprises a gun barrel 1 conically reduced towards the muzzle 2. The gun barrel 1 is mounted in a cradle (not shown) by means of a trunnion and is considered clamped at this point in oscillation-technical calculation. S depicts a bending-oscillation diagram, corresponding with the bending-oscillations excited in the barrel upon firing.

The plane-moment of inertia per length-unit J(X) and thereby the bending rigidity B(X) of the gun barrel can be increased only by enlargement of R (X), as can be ascertained from the above stated formula. Since the loading extremes, as shown, occur always in the forward third of the barrel, i.e. in the vicinity of the muzzle, the barrel 1 is equipped in this range with a rotation-symmetrical body, as a metal-ring-member 4 (FIG. 1), enlarging the plane-moment of inertia. The body 4 is fitted on the barrel 1 and is shrunken on the barrel, so that a very intimate and rigid connection is obtained with the barrel wall, i.e. as the barrel wall and the strutting body were made integrally of one piece. Such formation, wherein the stiffening body comprises a barrel reinforcement is of particular advantage. The body 4 forms in this manner a reinforcement of the gun barrel, which is capable of dampening effectively the bending oscillations excited upon firing. The experimental investigations with such reinforcements resulted in a reduction of the angle jump for 70 percent.

Referring again to the drawing, and in particular to FIG. 2, the reinforcement member may comprise a plurality of rings or beads 4' at predetermined distances on the barrel 1, which rings or beads 4' are disposed preferably within the range of occurring loading extremes.

While we have disclosed two embodiments of the present invention, it is to be understood, that these embodiments are given by example only and not in a limiting sense.

Claims

We claim:

1. A device on gun barrels for the reduction of the angle jump of a projectile, comprising

a plurality of reinforcement members fitted to the forward range of a gun barrel, and adapted to dampen bending oscillations occuring upon firing in said gun barrel,

said reinforcement members being disposed in the vicinity of the muzzle of said gun barrel, and comprise rotation-symmetrical bodies enlarging in this range the plane-moment of inertia of said gun barrel,

said plurality of reinforcement members being disposed spaced apart at predetermined distances within the range of adjacent occurring loading peaks in the vicinity of the muzzle of said gun barrel.