Gas Utilization Device For Automatic Guns, More Particularly For Automatic Shotguns

Abstract

The barrel of an automatic shotgun is provided with a downwardly depending cylindrical element which enclosed a portion of the cylindrical magazine. A sleeve-like element is slidably mounted on the magazine within the cylindrical element and an annular gas chamber is defined between the sleeve-like element and the cylindrical element. At least one communication aperture is formed between the barrel and the annular chamber and gas seals are provided between the sleeve-like element and the cylindrical element on opposite sides of the annular chamber. The recoil mass is slidably mounted on the cylindrical magazine adjacent the sleeve-like member so that the gases entering the annular chamber will drive the sleeve-shaped element against the recoil mass to actuate the mechanisms of the gun.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a gas operated device for automatic guns, more particularly but not exclusively for automatic guns.

2. Prior Art

In connection with the above type of guns, it is known in the art to base the operation of the mechanisms for the automatic loading of the gun and the structure and interconnection of these mechanisms on the principle of using the energy of the shot gas (more precisely, the energy from the gas) to drive a mobile recoil mass, which, in its reciprocating movement as each shot is fired, activates the above-mentioned mechanisms.

It is also known in the art to use a so-called shot chamber gas utilization device for exploiting the energy from the gas. The most common form of this device consists essentially of a cylinder-piston unit. The piston in this unit is driven by the shot chamber gas obtained from the barrel of the gun inside the cylinder and it transfers this drive to the aforesaid mobile recoil mass which activates the mechanisms of the autoloading gun. More precisely, a shot chamber gas utilization device of the above-mentioned type comprises essentially a cylindrical element integral with the barrel of the gun and enclosing a part of the cartridge magazine, which with the internal surface of the cylinder forms an annular chamber closed at the front.

This chamber is in communication by way of apertures provided in the wall of the barrel and in the wall of the cylinder with the interior of the barrel of the gun. The device also comprises a piston consisting of an annular element (ring-shaped) slidably mounted outside of the aforesaid part of the magazine within the chamber defined by the cylinder and the magazine itself. The gas obtained from within the barrel of the gun in the abovementioned annular chamber acts on the annular piston driving it rapidly towards and against the recoil mass, which generally consists of a sleeve element slidably and externally connected to the magazine and in contact with the piston.

To ensure the necessary sealing of the annular piston and the magazine on which the former is slidably mounted, this connection is provided with a relatively large amount of friction while simultaneously ensuring the desired sealing with respect to the shot chamber gas (under pressure) and the necessary mobility of the piston. Owing to the prearranged value of the friction, the course of the piston outside the cylinder is extremely limited since as soon as the piston leaves the annular chamber of the cylinder the gases begin to expand in a chamber with larger dimensions in communication with the atmosphere. The repositioning of the annular piston inside the cylinder for the utilization of the energy from the gases of a successive firing is effected by the same recoil mass, which, driven by a previously compressed spring, returns to the initial position. Examples of the known devices described above are disclosed in U.S. Pat. Nos. 2,909,101 and 3,200,710.

However, there is a technical problem which affects the known gas utilization devices of the type described above. This problem, which has hitherto remained unsolved, involves serious disadvantages. More precisely, this technical problem consists in that the shot combustion gases in the chamber defined by the cylinder and the part of the magazine enclosed by the cylinder are in contact with the outer lateral surface of the magazine thereby causing the formation on the same of deposits and directly to the formation of scale. These deposits in turn increase the friction between the mobile annular piston and the aforesaid part of the magazine on which the piston slides. This causes a reduction in the amount of drive which the piston exercises on the mobile recoil mass. This reduction increases with the frequency of use of the gun.

Along with this reduction there is the possibility of undesired jamming of the weapon. To prevent this, frequent cleaning and maintenance of the parts constituting the gas utilization device, is necessary. In addition to these disadvantages, a further disadvantage consists in that, owing to his inexperience or insufficient knowledge of the reciprocal connection of the elements constituting the device, the user frequently has to call on the services of a mechanic for the maintenance of the gun.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide a gas utilization device, the structural and functional features of which are such as to effectively solve the above technical problem, i.e., to provide a shot gas utilization device, the structure of which is such as to prevent contact between the gas and the outer lateral surface of the magazine thereby preventing the formation of deposits or scale between this surface and the piston which slides on the same.

Another object of the present invention is to provide a device of the above-mentioned type, the structural and operational features of which, apart from ensuring prolonged use of the gun on which the device has been fitted and also more reliable operation than the known devices, also render the device easy to produce and to fit on automatic guns presently in use, without requiring special adjustment of the structure of the gun itself. Neither will the application of this device require the use of other mechanisms or of numerous other constitutive elements, which would in some way complicate the already complicated structure of an automatic gun.

Another object of the present invention is to provide a shot gas utilization device which is relatively simple to produce and implement by way of known processes and using commercially available materials thereby rendering the device profitable from a stictly economical standpoint.

These and other objects, which will be made more apparent in the following description are achieved by a shot gas utilization device for automatic guns, more particularly for shotguns, comprising a cylindrical cartridge magazine extending parallel to the barrel of the gun. According to the invention, this device is characterized in that it comprises a cylindrical element connected to the barrel and enclosing a part of the magazine, a substantially sleeve-like element slidably and coaxially mounted on at least the above-mentioned part of the magazine and forming with the cylindrical element an annular chamber, means for sealing gas under pressure to isolate the chamber from the enclosed part of the magazine, an annular piston externally and coaxially connected to the substantially sleeve-like element, with which is joined in translation a recoil mass slidably mounted on the magazine outside the cylindrical element, at least one communication aperture between the barrel and the annular chamber formed by the cylindrical element and the substantially sleeve-like element; the gases entering the above chamber driving the substantially sleeve-like element against the recoil mass to activate the mechanisms of the gun.

Other objects, features and advantages of the present invention will be made apparent in the following detailed description of a preferred but not exclusive embodiment of a shot gas utilization device for automatic guns according to the invention provided by way of a non-limitative example with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic perspective view of an automatic shotgun on which the gas utilization device according to the invention has been fitted,

FIG. 2 is a perspective view of a gas utilization device according to the invention with the parts separated,

FIG. 3 is a sectional view on an enlarged scale of a gas utilization device according to the present invention,

FIG. 4 shows a section along the line IV--IV of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the above figures, the shot gas utilization device according to the present invention is illustrated in use on an automatic shotgun, diagrammatically indicated by 1 in FIG. 1, and comprising a cylindrical cartridge magazine 2 closed at the front by a threaded plug 3 and extending parallel to the barrel 4 of the gun below said barrel.

The shot gas utilization device according to the present invention comprises a cylindrical element 5 rigidly connected to the barrel 4 and enclosing a part of the magazine 2. A sleeve element 6 is slidably mounted with a certain amount of friction on the aforesaid part of the magazine. This sleeve element 6 defines with the lateral internal surface of the cylindrical element 5 an annular chamber 7. This annular chamber 7 is in communication with the interior of the barrel 4 of the automatic gun by way of a couple of apertures 8 and 9 (FIG.4) provided in the wall of the barrel and the cylindrical element 5, and extending in an inclined manner downwards and towards the back of the barrel 4. The lateral internal surface of the cylindrical element 5 defines, in front, at the mouth of the apertures 8 and 9 in the annular chamber 7, a plurality of spaced annular shoulders 10 constituting, in effect, the gas sealing rings in contact with the lateral, outer surface of the sleeve element 6. The gas utilization device according to the present invention also comprises an annular piston 11 solidly connected externally to the sleeve element 6, with which it forms a single piece. Advantageously, further annular rims 12 and 13 having an external diameter equal to the outer diameter of the annular piston 11 and constituting the elements for sealing the gas under pressure in contact with the lateral internal surface of the cylindrical element 5, are provided downstream of the annular piston 11 on the sleeve element 6. Outside the cylindrical element 5, the sleeve element 6 defines a final annular rim 14 having an outer diameter which is larger than the internal diameter of the cylindrical element 5 and which, advantageously, is equal to the outer diameter of the cylindrical element 5. The sleeve element 6 is provided outside the cylindrical element 5 and at its end opposite to the end provided with the annular rim 14, with an arresting element 15 (FIG. 3). This arresting element 15 advantageously consists of a pair of half rings 16 and 17 (FIG.2) connected externally to the sleeve element 6 by way of an elastic band 18. This arresting element 15 has an larger outer diameter than the internal diameter of the cylindrical element 5.

A recoil mass generally indicated by 19 in FIG. 2, is slidably mounted on the magazine 2 of the gun on which the gas utilization device according to the invention is fitted. This recoil mass consists of a sleeve element 20 terminating at the front in an annular rim 21 having the same diameter and shape as the annular rim 14 at the end of the sleeve element 6 with which it is intended to cooperate. Rigidly connected to the sleeve 20 are prepositioned shaft-like elements or rods 22 and 23 for the activation of the mechanisms normally provided in automatic shot guns for the automatic loading process. The above described device and the recoil mass, which constitutes part thereof, are housed in the stock 24 of the gun, forming a chamber 25 of large dimensions, which communicates with the atmosphere via the apertures 26.

The shot gas utilization device according to the invention operates as follows: When the automatic gun is ready to be fired, the device according to the invention is in the position indicated in FIG. 3, more precisely, the terminal or rear annular rim 14 of the sleeve element 6 is in contact with the rear mouth of the cylindrical element 5 while the annular piston 11 is positioned close to the openings of the passages 8 and 9 in the annular chamber 7 defined by the cylindrical element 5 and the sleeve element 6. The front end 21 of the recoil mass 19 is in contact with the terminal annular rim 14 of the sleeve element 6. This contact is maintained by the spring means normally provided in the mechanisms of an automatic shotgun. These means are not represented.

After a shot has been fired, as soon as the charge clears the openings of the passages 8 and 9 in the barrel 4 of the gun, some of the gas reaches the interior of the chamber 7. There the gas acts on the annular piston 11, which, together with the sleeve element 6 moves rapidly backwards driving the recoil mass 19 against the spring means (not shown). The course of the annular piston 11 and the sleeve element 6, with which the piston forms a single piece, has a value slightly greater than the length of the cylindrical element 5 at the rear of the passages 8 and 9. In fact, as soon as the annular piston 11 leaves the sealing engagement with the lateral internal surface of the cylindrical element 5, the gases, which were at first under pressure in the cylinder 7, expand in the larger chamber 25 and from there are discharged outside the stock 24 by way of the apertures 26. The action of the gases on the piston 11 then begins to cease. Owing to the friction normally present with the sleeve element 6 slidably mounted on the magazine 2, this action stops almost instantaneously. Furthermore, the arresting element 15 is provided to ensure that this arrest occurs. This element 15 is mounted outside the sleeve element 6 at a distance from the front end of the cylinder 5 corresponding to the course of the piston. The return movement of the sleeve element 6 and the annular piston 11, which is integral therewith, to the initial position, is governed by the return of the recoil mass 19 driven by the spring means.

It is apparent from all that has been described and illustrated that the gas utilization device according to the present invention completely fulfils the aims in view and resolves the previously defined technical problem. The shot gases are actually no longer in contact with the magazine 2 on which slide both the sleeve element 6 with the annular piston 11 and the recoil mass 19. Apart from the presence of the sleeve element 6, the isolation of the magazine from contact with the gases is further ensured by the presence of the sealing rings 10 defined inside the cylindrical element 5, at the front of the passages 8 and 9 and by the sealing rings 12 and 13 integral with the sleeve element 6 at the rear of the annular piston 11. A constructive feature which constitutes one of the features according to the invention and which is intended to ensure the above-mentioned isolation of the magazine from the gases, thus solving the technical problem cited initially, consists in that the sleeve element 6 is provided with greater length than the course of the annular piston 11 when driven by the gases.

The above described invention may obviously be modified in various ways without departing from the scope thereof. It is also possible to replace elements by equivalent technical elements. The materials used and dimensions employed may vary as necssary.

Claims

What is claimed is:

1. A gas utilization device for automatic guns, more particularly automatic shotguns of the type which comprise a cylindrical magazine extending parallel to the barrel of the gun and below the same, said device being characterized in that it comprises a cylindrical element connected to the barrel and enclosing a part of the magazine, a substantially sleeve-like element slidably and coaxially mounted on at least the said part of the magazine, an annular chamber defined between said sleeve-like element and the cylindrical element, means for sealing the gas under pressure to isolate said chamber from said part of the magazine, an annular piston connected externally and coaxially to the substantially sleeve-like element, a recoil mass slidably mounted on the magazine outside the cylindrical element adjacent said sleeve-like element, at least one communication aperture between the barrel and the annular chamber formed between the cylindrical element and the substantially sleeve-like element; the gases entering in said chamber driving the annular piston and the substantially sleeve-shaped element against the recoil mass thereby causing activation of the mechanisms of the gun.

2. A device according to claim 1, characterized in that the means for sealing the gas under pressure to isolate the annular chamber from said part of the magazine comprises a plurality of annular shoulders defined on the lateral internal surface of the cylindrical element in front of the communication aperture between the barrel and the annular chamber; said shoulders being in constant sliding contact in a gas sealing manner with the substantially sleeve-like element.

3. A device according to claim 1, characterized in that the substantially sleeve-like element is provided at the rear of the annular piston with a plurality of annular rims having an external diameter equal to the outer diameter of said annular piston and constituting, in effect, gas sealing elements in contact with the lateral internal surface of the cylindrical element.

4. A device according to claim 3, characterized in that the substantially sleeve-like element is provided at its end with arresting means cooperating with the base of the cylindrical element and designed to limit the course of the annular piston and to accurately position the annular piston within the cylinder before each shot.