WO2005003673A1

WO2005003673A1 - Apparatus for monitoring the loading state of a gun employing a separate-loaded ammunition system

Info

Publication number: WO2005003673A1
Application number: PCT/FI2004/000431
Authority: WO
Inventors: Jari Pekka Poutanen
Original assignee: Patria Vammas Oy
Priority date: 2003-07-08
Filing date: 2004-07-07
Publication date: 2005-01-13
Also published as: FI20031044A; FI20031044A0; FI115159B

Abstract

An apparatus for monitoring the loading state of a gun employing a separate-loaded ammunition system. In the apparatus, a radiation source (3) is arranged on one side of the gun in a cradle (2), and a receiver (4) on the opposite side for measuring the amount of radiation emitted from the radiation source, and a display element (6) for indicating the amount of radiation absorbed by the receiver (4), an incorrect position of the projectile being indicated with the display element (6).

Description

APPARATUS FOR MONITORING THE LOADING STATE OF A GUN EMPLOYING A SEPARATE-LOADED AMMUNITION SYSTEM

BACKGROUND OF THE INVENTION [0001] The invention relates to an apparatus for monitoring the loading state of a gun employing a separate-loaded ammunition system, in which gun the gun barrel is installed longitudinally movable in a cradle. [0002] In guns, a so-called separate-loaded system is typically employed, wherein the actual projectile, i.e. a grenade, is first loaded into the gun barrel, a propelling charge employed for propelling the projectile being then loaded into the barrel. The projectile is typically loaded by the use of a so- called flick rammer, the projectile flying freely in the charge chamber a distance of up to one meter before stopping by the action of friction in a so-called forcing cone between the charge chamber and the rifled part of the gun barrel. When this happens, the projectile should get squeezed into the forcing cone and stay therein in position until being propelled. Once the projectile is loaded, the propelling charge, i.e. gunpowder, is inserted into the charge chamber, depending on the firing task, in packages of different size/length or in a so-called cartouche case, the charge chamber being finally closed at the back with the breechblock of the gun. [0003] The volume and length of a normal propelling charge are determined such that the charge does not reach the back of the projectile, wherefore it does not support the projectile in position. For this reason, the projectile is suspended in position by the action of the friction between its driving band and forcing cone. The projectile may be detached and fall against the propelling charge as the breechblock is closed or thereafter. Since in this case the space between the projectile and the barrel is not tight, the powder gases caused by the burning of the propelling charge following the firing of the gun may flow from between the projectile and the barrel until the projectile starts to move by the action of the pressure generated. As a result, both the projectile and the inner surfaces of the barrel may be damaged, and the projectile does not fly up to the target; instead, its air passage remains shorter. In the worst case, the explosive agent contained by the projectile may explode, resulting in a barrel explosion and complete destruction of the gun. [0004] An additional feature in most guns is that the charge chamber is located slidably inside a separate, e.g. tubular cradle, since, because of recoil, the barrel has to be able to move backwards from the firing position after the firing. Accordingly, no projecting measurement devices or sensors can be attached to the gun barrel at the charge chamber.

BRIEF DESCRIPTION OF THE INVENTION [0005] The object of the present inventions is to provide a device for monitoring the loading state and for ensuring that the projectile is in the correct position before the gun is fired. The apparatus of the invention is characterized in that a radiation source is arranged on one side of the gun barrel in the cradle, and a receiver on substantially the opposite side of the gun barrel for measuring the amount of radiation emitted from the radiation source, and a display element for indicating the amount radiation entered the receiver, that the radiation source and the receiver are arranged in the cradle relative to the position of the gun barrel according to the firing instant such that when a projectile loaded into the gun barrel is in the correct position, the radiation passes through the gun barrel via a point of a charge chamber, which is provided between the projectile and a propelling charge and contains substantially only air, whereby the projectile, having been detached from its correct place, settles on the radiation travel path and suppresses the amount of radiation entering the receiver such that an erroneous position of the projectile can be indicated with the display element. [0006] The essential idea of the invention is to fasten a radiation source to the cradle around the gun barrel for transmitting electromagnetic radiation through the gun barrel to a receiver placed on its opposite side. A further essential idea of the invention is to place the radiation source and the receiver in the cradle at such a point that when the projectile to be employed is placed in the correct position in the charge chamber after loading, an empty space is provided in the charge chamber behind the projectile, and it does not substantially suppress the radiation. This being so, and the gun being loaded and the breechblock closed, the display element connected to the receiver and the amount of radiation entered the receiver can be used to indicate if the projectile has stayed in the correct position or if it has possibly fallen into an incorrect position. This is based on the fact that should the projectile fall, the material of both the gun barrel and the projectile is placed between the radiation source and the receiver, which significantly suppresses the radiation, thus enabling accurate detection of the incorrect position of the projectile. According to a preferred embodiment of the invention, the electromagnetic radiation is generated by the use of a radioactive material having a sufficiently shortwave and high-energy radiation, so that the radiation is able to penetrate the walls of the gun barrel to the receiver. Such a radiation source is preferably a radioactive isotope transmitting high-energy gamma radiation. In accordance with still another preferred embodiment of the invention, the aim is to concentrate the radiation into an as narrow cone as possible, allowing radial, but closed borings, by means of which the radiation is made suitably shaped, to be bored on the outer surface of the gun barrel at the measuring point. According to a second preferred embodiment of the invention, the radiation source and the receiver are placed movable in the longitudinal direction of the gun barrel relative to the cradle such that when different projectiles and propelling charges are used, the radiation source and the receiver can be moved into a suitable position relative to the projectile, if required. In accordance with still a third preferred embodiment of the invention, two or more radiation sources and the same number of receivers are employed, placed at suitable points in accordance with the dimensions of the different projectiles and propelling charges.

BRIE DESCRIPTION OF THE FIGURES [0007] The invention is described in detail in the accompanying drawings, in which Figure 1 schematically shows an apparatus according to the invention, installed in a gun, Figures 2a and 2b are schematic sectional views of the operation of an apparatus according to the invention with the projectile in the correct position in the longitudinal and transverse directions, respectively, of the gun barrel, Figures 3a and 3b show a situation corresponding to Figures 2a and 2b with the projectile in an incorrect position, and Figures 4a and 4b show another embodiment of an apparatus according to the invention.

DETAILED DESCRIPTION OF THE INVENTION [0008] Figure 1 schematically shows an apparatus according to the invention. The gun barrel and the cradle are shown in a position where they usually are relative to one another at a firing instant. The apparatus is a radiation source 3 installed on one side of a cradle 2 provided around a gun barrel 1. In the present and other figures, the cradle is shown tubular, but other kinds of cradle types, fully known per se, are also feasible. On the opposite side of the cradle 2 is provided a receiver 4, which is hit by the radiation emitted from the radiation source 3 and passing through the gun barrel 1. The receiver 4 is connected to a monitoring device 5 having some kind of a display element 6 for indicating the loading situation in the gun barrel. The display element 6 may be a signal lamp, a voice-producing device, some kind of a screen for displaying data, or any other device with which the data given by the indicator can be indicated to the user of the gun. Dashed lines 3' and 4' indicate that, when required, the radiation source 3 and the receiver 4, respectively, can be moved relative to the cradle 2 in the longitudinal direction of the gun barrel 1 , should this be necessary because of variation in the dimensions of the projectiles and propelling charges employed. [0009] Figure 2a is a longitudinal section of the gun barrel 1 at a charge chamber 1a in a situation when a projectile 7 is located in its correct position, and Figure 2b shows a section of the charge chamber along line A - A. Figure 2a shows that the projectile 7 is settled in the intended position relative to a forcing cone 1 b provided between the charge chamber and the rifled portion of the gun barrel. In this situation, a driving band 7a, usually provided in the projectile and made from a soft material, such as copper or brass, is pressed tightly against the surface of the forcing cone 1 b, locking the projectile in place by means of friction. Behind the projectile 7, at a distance from the projectile, is a propelling charge 8, typically composed of several separate packages containing gunpowder. Behind the propelling charge is provided a breechblock 9 for closing the back of the charge chamber during shooting. [0010] As Figure 2a shows, the radiation source 3 and the receiver 4 are located in the cradle 2 such that they are almost touching the outer surface of the gun barrel 1. This distance is not very essential per se, but only air preferably exists between the radiation source 3, the receiver and the gun barrel 1. Since the cradle 2 is not subject to any significant stresses in this respect, openings 2a or holes can be provided in the cradle, when needed. Borings 10 are also provided at the charge chamber 1a in the gun barrel 1 in its radial direction such that the borings 10 are substantially at the same point and most preferably substantially at the middle axis of the charge chamber 1a. The radiation source 3 and the receiver 4, in turn, are installed such that the travel path of the radiation from the radiation source at the borings 10 is through the walls of the gun barrel. In the situation of Figure 2a, only the wall thicknesses of the gun barrel 1 are at the radiation source 3 and the receiver, i.e. the measuring point, or, when borings are used, only the wall thicknesses remaining at the borings 10, and substantially air in the charge chamber 1 b. Naturally, if the cradle is not provided with openings or holes, the travel path of the radiation in that situation may also have the thicknesses of the material of the cradle. In this situation, a given amount of radiation substantially passes through the gun barrel 1 , indicating that no other material exists at that particular point. Figure 2b shows the corresponding fact by a section along line A - A. [0011] Figures 3a and 3b show a situation corresponding to Figures 2a and 2b when the projectile 7 is detached and fallen to rest on the propelling charge in an incorrect position. In this situation, the metal cover of the projectile and the explosive agent are on the travel path of the radiation and suppress the radiation as compared with the situation in Figures 2a and 2b. This reduction in the amount of radiation is also detected with the receiver 4 and, as a result, the display element 6 indicate that the loading situation is incorrect. This prevents the gun from being unintentionally fired in a situation when it could be damaged, and in the worst case harm the users. [0012] Figures 4a and 4b show a second embodiment of an apparatus according to the invention corresponding to Figures 2a and 2b. In this embodiment, neither the cradle 2 nor the gun barrel 1 is provided with openings or borings; instead, the radiation passes through the material of both the cradle and the walls of the gun barrel. In this embodiment, too, the settling of the projectile onto the radiation line suppresses radiation to a degree that an incorrect charging of the projectile can be observed with the receivers and indicated with the display element. [0013] A radioactive material emitting suitable radiation is employed in the radiation source 3. In practice, the most preferable radiation sources include radioactive isotopes emitting high-energy gamma radiation, such as Cs137 or Co60. In this case, the receiver, in turn, is a radiation indicator, i.e. typically a calculator measuring the amount of radioactive radiation. Since the radiation source and the receiver are fastened to the cradle 2, which moves during shooting significantly less than the gun barrel 1 , and which is subjected to significantly lower acceleration forces than the gun barrel, they endure the forces and stresses they are subjected to during usage, which they would not do if installed in the gun barrel. [0014] If the dimensions of the projectiles and propelling charges employed in the gun are suitable, one radiation source and receiver may be sufficient. If the dimensions of the projectiles and propelling charges vary significantly, an embodiment can be utilized, wherein the radiation source and the receiver are movable to a suitable point in the longitudinal direction of the gun barrel relative to the cradle according to the projectile and propelling charge employed. Furthermore, if the dimensions of the projectiles and propelling charges employed allow two or more separate points to be clearly distinguished that are suitable for indicating the position of the projectile, two or more fixedly installed radiation sources and, correspondingly, an equal number of receivers can also be employed, whereby a given radiation source/receiver pair indicates, for each projectile and propelling charge combination, the correct or incorrect position of said projectile. [0015] In the description and the drawings, the invention is described only by way of example, and is in no way restricted thereto. It is essential that to a point outside the gun barrel in which, with the gun in a firing position and the projectile in the correct position, an empty space containing only air exists behind the projectile, a radiation source and an indicator are fastened to opposite sides of the barrel for ensuring that the projectile is in the correct position in the charge chamber at the firing instant.

Claims

CLAIMS 1. An apparatus for monitoring the loading state of a gun employing a separate-loaded ammunition system, in which gun the gun barrel (1) is installed longitudinally movable in a cradle (2), characterized in that a radiation source (3) is arranged on one side of the gun barrel (1) in the cradle (2), and a receiver (4) on substantially the opposite side of the gun barrel (1) for measuring the amount of radiation emitted from the radiation source (3), and a display element (6) for indicating the amount radiation entered the receiver (4), that the radiation source (3) and the receiver (4) are arranged in the cradle (2) relative to the position of the gun barrel (1) according to the firing instant such that when a projectile (7) loaded into the gun barrel (1) is in the correct position, the radiation passes through the gun barrel (1) via a point of a charge chamber (1a), which is provided between the projectile (7) and a propelling charge (8) and contains substantially only air, whereby the projectile (7), having been detached from its correct place, settles on the radiation travel path and suppresses the amount of radiation entering the receiver (4) such that an erroneous position of the projectile (7) can be indicated with the display element (6). 2. An apparatus as claimed in claim 1, characterized in that the radiation source contains a radioactive isotope emitting high-energy gamma radiation, such as Cs137 or Co60. 3. An apparatus as claimed in claim 1 or 2, characterized in that the radiation is directed to pass substantially through the middle axis of the charge chamber (1a). 4. An apparatus as claimed in any one of the preceding claims, characterized in that the display element (6) is a signal light or a voice- producing device. 5. An apparatus as claimed in any one of the preceding claims, characterized in that one or more blind holes (10), directed from the outer surface of the gun barrel (1) towards the charge chamber (1a), are bored in the gun barrel (1) on the radiation travel path. 6. An apparatus as claimed in any one of the preceding claims, characterized in that the cradle (2) is provided with through-openings (2a) on the radiation travel path. 7. An apparatus as claimed in any one of the preceding claims, characterized in that at least one radiation source (3) and receiver (4), respectively, are movable relative to the cradle in the longitudinal direction of the gun barrel (1). 8. An apparatus as claimed in any one of the preceding claims, characterized in that at least two radiation sources (3) and two receivers (4), respectively, are installed therein for different projectiles at different points of the cradle (2) in the longitudinal direction of the gun barrel (1).