US2831287A

US2831287A - Cartridge chamber with abutments

Info

Publication number: US2831287A
Application number: US486654A
Authority: US
Inventors: Maillard Bernard
Original assignee: Brevets Aero Mecaniques SA
Current assignee: Brevets Aero Mecaniques SA
Priority date: 1954-02-16
Filing date: 1955-02-07
Publication date: 1958-04-22
Anticipated expiration: 1975-04-22
Also published as: DE1021759B; FR1122130A; CH322669A; GB765300A

Description

April 1958 B. MAILLARD 2,831,287

CARTRIDGE CHAMBER WITH ABUTMENTS Filed Feb. 7, 1955 s Sheets-Sheet 1 ZI/WEJY ATTDHNEKS B; MAILLARD CARTRIDGE CHAMBER wmn ABUTMENTS April 22, 1958 7 Filed Feb. 7, 1955 3 SheetsSheet 2 lu lll-l llll @QQQR EzY ATTDPINEYS April 22, 1958 B. MAILLARD 2,831,287

7 CARTRIDGE CHAMBER WITH ABUTMENTS Filed Feb. 7, 1955 v s Sheets-Sheet :5

INVENTUR W I ATTDHNEYfi Claims priority, application Luxemburg z February 16,1954

4 Claims. (c 1. 42-76) I Application February 7 The present invention relates to guns making use of ammunition in the form of cartridges, such cartridges including a cartridge .case, which is generally metallic, provided with a primer. and containing the propelling charge and a projectile tightly fitted case, for instance by shrinking.

. My inventionis more especially but not exclusively concernedwith automatic guns. and in particular those of the open breech type. r

The object of my invention isto provide a system of this kindwhich is betteradapted to meet the requirements of practice thanthose used up to the presenttime.

The cartridges withwhichmy invention is concerned include at least itwo annular bearing areas locate'done aheadof the other and adapted to cooperate with two abutments carried by the gunbarrel respectively and also located at a'distance fromeach other, My invention is characterized in that 1 said located'at a distance fromeach other such. thatevery cartridge, near the end of the movement of introduction thereof into the cartridge chamber, isfirst "braked by deformation ofone of said bearing areas on the corresponding cartridge chamber abutment, then positioned in a very accurate manner 'by cooperation of the second hearing area against the corresponding abutment of the cartridge chamber. 1

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way ofexample and in which: Fig. 1 isa longitudinal sectional view of the cartridge chamber ,of an automaticgun, with acartridge being introduced into said chamber,

according to my invention. Figs. .Z and arediagrammatic sectional views on an enlarged scale ,corresponding to successive positions of the cartridge in the cartridge chamber.

Fig. 4 is a longitudinal sectional view by a horizontal .plane,'showing a portion of the,breech mechanism of a gun according to my invention.

present invention essentially includes a cartridge case}, generally metallic, provided with a primer in its base and containing the pro- A cartridge according to the pelling powder charge 3 and a pro ectile 4; tightly fitted in for instance by shrinking. r.

the neck of said cartridge case, Such acartridge is to be introduced and suitably positioned in the cartridge chamber 1 of the gun. 1 It will be understood that whateverbe the firing system (either arnechanical or an electrical one), a good operation ofthe gun'will'beobtained only if all of the cartridges successively introduced into the cartridge chamber occupy the same position therein at the time of firing. In other .words"itis necessary, in' order to obtain a satisfactory firing for the cartridges, to prevent any possibility of the "successive cartridges being located in slightly difierent axial positions.

lthas already been proposed to obtain this resultby providing the cartridge case-with an annular flange infitended to corneinto contact with therear edge of the in the neck of said cartridge.

' of its travel in. the cartridge chamber,

bearing areas are shaped and I 2 gun barrel, so as,to stopthe cartridge when it is introduced intogthe'cartridge chamber and to position it with respect to said chamber.

However, with such an arrangement, the cartridge undergoes a rather violent shock which may cause the projectile 4 to be driven at least partly out of the front end of the cartridge case. In this case, even if the projectile remains partly held by the cartridge case, the volume in which the propelling powder charge is burning is modified so that firing becomes irregular.

Of course, if the projectile 4 is loosened entirely from the cartridge case, the propelling charge may come into contact with a hot gun barrel and premature firing can then take place with the dangers it involves.

In order to obviate these drawbacks, it has been proposed to brake the movement of the cartridge at the end so that it is less violently stopped.

For instance, such a braking was obtained by a deformation of the shoulder e of cartridge case 2, this deformation being produced when said shoulder comes into contact with an abutment carried with the gun barrel.

However such a construction does not always make it possible to position the cartridge accurately in the cartridge chamber, especially when the speed at which the cartridge is introduced into the cartridge chamber is very high,as it is the case for automatic guns having a high rate of firing.

In this case, due to the unavoidable difierences existing in the manufacture of'the cartridge case and also to the variations in the rate of firing of the gun, the violence of the shock of shoulder e against the abutment carried by the gun barrel varies and the positioning of the rear edge of the cartridge at the end of its introduction in the cartridge'case also varies.

The present invention is intended to back.

As illustrated by Fig. 1, the cartridge case 2 includes at obviate this drawleast two bearing areas located one ahead of the other movement with respect to cartridge chamber 1, is first against the of the second bearing area braked by deformation of one of said bearing areas corresponding cartridge chamber abutment, then positioned in a very accurate manner by engagement against the corresponding cartridge chamber abutment. The first area will be hereinafter called braking area and the second one positioning area.

It will be understood that owing to such an arrangement and to the fact that the braking area and the positioning area act one after the other, it will be possible to obtain a more accurate positioning of the cartridge at the end of its introduction, without subjecting the cartridge to violent shocks which might loosen the projectile 4 in the neck of the cartridge case.

This will be possible because the braking area and the corresponding abutment of the cartridge chamber can be devised in such manner that when, subsequent to their cooperation, the positioning area comes into contact with its abutment, the speed of the cartridge has been sufficiently lowered to reduce the shock of the positioning area against the rear abutment to an admissible value.

The parts will be arranged in such manner that, account being taken of the functional characteristics of the gun is to say when the speed of introduction of the cartridge is the lowest possible, the deformation of the braking area just enables the cartridge to' fit in the cartridge chamber Without any shock of the positioning area against the rear abutment of the cartridge chamber. In all other firing circumstances, the positioning area will have an active function and will come to bear against its abutment with a slight shock involvingno risk of loosening projectile 4 from the neck of the cartridge case.

For instance, in the case of a gun of the open breech type, the braking area may achieve by itself a correct positioning of the cartridge whenthe first round is being fired, that is -to say when the breech starting from its rear position, where it is held by the detent system, moves toward the front under the only action of the recuperator spring. In guns of this type, when a burst is being fired, the breech-block has a recoil movement of a high amplitude at the end of which it compresses a damping and accelerating spring the action of whichis added to that of the recuperator spring so as to return toward the front the breech case the speed of displacement of which is then higher, at the end of its frontward stroke, than the speed it had when the first round was being fired. Thus when firing a burst, the positioning area will act, after deformation of the braking area, for every shot that is fired.

Preferably, the braking area of the cartridge case is located ahead of the positioning area and for this purpose, the braking area is advantageously constituted by of the cartridge case 2. The positioning area is then constituted by an annular flange b located in of the cartridge case (for instance immediately ahead of the extractor groove),'said flange having a diameter higher than the diameter of the rear part of the body of the cartridge case.

In order to enable the shoulder e of cartridge case 2 to perform, by deformation, the braking effect expected therefrom, the abutment of the cartridge chamber 1 that cooperates with said shoulder 2 preferably has a shape different from that of said shoulder so that the latter comes to fit exactly against said abutment only at the end of its movement but at the beginning of the braking period a gradual deformation of said shoulder is produced which causes the cartridge to be slowed down gradually as it is being forced into the cartridge chamber.

For instance, advantageously, the abutment 2 of the cartridge chamber and the shoulder e of the cartridge case are both of frusto-conical shape but their respective apex angles are different from each other, the shoulder e of the cartridge case having an apex angle (for instance averaging 45) greater than the apex angle of the abutment e of the cartridge chamber 1 (which for instance averages 30).

With such a gun, a correct positioning of the cartridge in the cartridge chamber will be ensured:

When the first round is being fired, by the mere deformation of the shoulder e of the cartridge case 2 to come against the abutment 2 of the cartridge chamber (flange b being then merely brought into contact against its abutment, at the rear of the cartridge chamber).

When the following rounds are fired, during a burst of fire, the positioning of the cartridgcs is obtained both by deformation of shoulder e and by a slight shock of flange 12 against the rear edge of the cartridge chamber.

Figs. 2 and 3 show the most characteristic positions during the deformation of shoulder e.

Said shoulder, after it has come into contact with the abutment 6 or" the cartridge chamber (Fig. l) is gradually deformed so as to fit exactly against abutment e This deformation, which produces a progressive braking, corresponds to a relative displacement which, for a 20 mm. gun, may average 2 mm. (Fig. 2). Then the cartridge still further moves by a distance a considered example, averaging 1.2 mm.) in the course of which the braking action still takes place by driving 7 firing.

in the cartridge chamber, this displacement being produced by a part 6 capable of having a complementary forward displacement once the locking members have finished their frontward movement. 7

With a gun of this type, the fact that every cartridge is always positioned in exactly the-same position at the end of its introduction movement into the cartridge chamber makes it sure that the pivoting movement of the lockin'g' members takes place in the same conditions and that the limitation of the axial movement of the locking members is always produced by the fact that ridge X is in contact with the rear end face of the cartridge case. Therefore, the cartridge cannot be driven too deeply into the cartridge chamber, in which case the locking members would come into contact with the rear edge of the gun barrel, thus deteriorating said-gun barrel or said locking members. I

In a general manner, while I have, in the above de' scription, disclosed what I deem to be practical and 'eflicient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form'of the: parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

What I claim is:

1. In combination, a gun having a cartridge chamber provided with a front annular abutment and a rear annular abutment, and a cartridge for use in said gun including a cartridge case having two annular projecting bearing areas for cooperation with said abutments respectively, said areas being shaped and said cartridge case to cause one of them to be in contact with the corresponding cartridge chamber abut- (in the above ment before the other bearing area comes into contact with the other the cartridge in the cartridge chamber is braked during a short period immediately preceding its final fixation in said chamber.

2. In combination,- a gun having a cartridge chamber provided with a front annular abutment and'a rear annular abutment, and a cartridge for use in said gun including a'cartridge case having a front annular shoulder for cooperation with said cartridge chamber front annular abutment, said shoulder and said front abutment being of different shapes respectively so that said shoulder must undergodeformation to come to fit against said front abutment, said cartridge case further having a rear projecting annular bearing area for cooperation with said cartridge chamber rear annular abutrnnhthe distance between said shoulder .and said rear bearing area being greater than the distance between 'said abutments, whereby the movement of the cartridge in the cartridge chamber is braked during a short period immediately precedingits final fixation in said chamber.

3. In combination, a" gun having a cartridge chamber provided with a front frusto-conical abutment and a rear annular abutment, and a cartridge for use in said abutment b (Fig. 3). The

gun for which such an arpo sitioned along gun including a cartridge case having afront frusto-conical shoulder for cooperation with said cartridge chamber front abutment, the apex angles of said shoulder and said front abutment respectively being different so that said shoulder must undergo deformation to come to fit against said front abutment, said cartridge case further having arear annular flange projecting therefrom for cooperation with said cartridge chamber rear abutment, the distance between said shoulder and said flange being greater than the distance between said cartridge chamber abutrnents, whereby the movement of the cartridge in the cartridge chamber is braked during a short period im- :mediately preceding its final fixation in said chamber.

4. In combination, a gun having a cartridge chamber provided with a front frusto-conical abutment and a rear annular abutment, and a cartridge for use in said gun including a cartridge case having a front frustoconical shoulder for cooperation with said cartridge chamber front abutment, the apex angle of said shoulder being greater than the apex angle of said front abutment so that said shoulder must undergo deformation to come to fit against said front abutment, said cartridge case further having a rear annular flange projecting therefrom for cooperation with said cartridge chamber rear abutment, the distance between said shoulder and said fiange being greater than the distance between said cartridge chamber abutments, whereby the movement of the cartridge in the cartridge chamber is braked during a short period immediately preceding its final fixation in said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,573,451 Keller et al. Oct. 30, 1951 2,590,981 Lippert et al. Apr. 1, 1952 FOREIGN PATENTS 237,192 Germany Aug. 1, 1911 714,348 Germany Nov. 27, 1941 273,435 Switzerland May 1, 1951