IL39860A - Feed mechanism for semi-automatic and automatic fire-arms - Google Patents

Description

on TOa »>3 niay tn itaias t 'DDlOIK rut. D'*BD1B1K »Sf| BREVETS AERO- ECANIQtJES 3,A C, 37909 - - The present invention relates to semi-automatic and automatic fire-arms of calibre advantageously comprised between 20 and 50 mm. Such fire-arms recock themselves automatically after each round, and the firing of the following round can either require an action on the part of the gunner (semi-automatic fire-arms) or not (automatlo firearms).

According to the invention, there is provided a semi-automatic or automatic fire-arm having two feed mechanisms articulated on the breechcase one on each side thereof and controlled so that one of them is in firing position when the other is out of firing position and vice versa, each feed mechanism having a mechanism for advancing cartridges, a mechanism for transmitting motion to the advancing mechanism housed in the feed mechanism and a driving member which is itself adapted to be displaced in a direction substantiall parallel to the axis of the barrel of the fire-arm, characterized by the fact that the fire-arm comprises for the two feed mechanisms a single motor member having alternating longitudinal motion, connected to a recoiling part of the fire-arm and of form and position such that it meets, during its recoil motion, only the driving member of the feed mechanism that is in firing position.

The invention is illustrated by way of example, in the accompanying drawings, in which: Figures 1 and 2 (both divided by a vertical broken line into two parts a and b intended to be considered end to end) show a fire-arm according to the present invention, respectively in vertical section and In horizontal section Figures 3 and 4 are sections along the lines III and I? respectively o Figure lj and Figure 5 illustrates the operation of the ejection system visible in Figure l;./: The fire-arm shown in the drawings is a heavy machine gun of calibre between 20 and 30 mm. , for example ' ·" - 5 - , ' ■ ■ and at the exterior of thi3 breechblock, without play, •to the casing 18. The lugs 13 of the breechblock 11 are k situated on the same cylinder of revolution as a part at ., least of the exterior surface of the casing 18, which permits the breechblock 11 to..-be guided by the contact' of the casing '18 and of at least sore of ite lugs 13 , with the same surface (which will be more explicitely described hereafter). A spring 111 acting on the. firing . pin 21 tends to push the uni't- formed by the firing- pin ;■■'.· 21 and the casing 18 'towards the front of the breechblook In order to transform into a rotary, movement of · the ' breechblock 11, the translatory movement which is. • j ..produced between the casing 18' and this breechblock [when the breechblock arrives substantially at the position of closing shown in Figures .1 and 2, ;the ■ . / spindle 20 carries two cylindrical rollers 22 (Pig. 4 ) ., •r co-operating respectivel with skews 22a formed in- a , · cyclindrical enlarged portion 23 of the breechblock 11., ' At its exterior surface', the casing 18 carries two. longitudinal projections 4 and 25 whose longitudinal lateral -faces 24a and 25a co-operate with the -interior- faces- of the large sides 5 and 6 of the breechcase 2 (see Figure 4) to. prevent the casing from turning ' .. at the interior of this breechcase. The projection 24 • comprises:;; a front face 24b and adapted to co-operate , with a sear 26 for stopping .the breech mechanism. in th^ open position. The projection 25 comprises a front face . .' 25b adapted to co-operate, on heoone fajand with a unlocking pusft-p.iece 27 (actuated in the manner 1 with respect to the breechcase 2, and on the other hand with a relocking device which permits the breechblock 11.to be . brought back towards the rear after the breechblook has been stopped in the closing position. Such a recocking device can comprise a chain 26, one link of which carries a hook for. the face 25b. The chain 28 is stretched between a front idler pinion 29 and a rear pinion 30 fixed on a spindle 31 rigid with a crank 32. The projection 25 further. co-operates by the rear with an ejector 33» mounted on a transverse spindle 34, for the purpose of making it tip, the projection 25 having a longitudinal groove 25c for the passage of the ejector.

Betweentwo of . its lugs 13, the breechblook 11 carries an extractor 35» and on the diametrically opposed side, it has a groove 36»' for the passage of the ejector 33» which, leads into the oup-shaped recess 12. The extractor can be maintained in place by a leaf-spring 37. ~' To maintain the casing 18 imperatively in its extreme rear position with respect to the breechblock 11 during the reciprocating movement of the breech mechanism 1 inside the ... breechcase 2, a leaf-spring 38, carried by the breechblook 11, tends to prpject by its rear part against a' bearing face 39 of the casing 18. An inclined surface 40, carried by the breechoase 2, can retract the leaf-spring 38 by acting on a push-piece 41 passing through the casing 18.

That being the case, the part 3-6 of the breechcase that is of substantially rectangular cross- :-' . ·, '·'. section..has, at the level of the cartridgev introduction openings 8, four guiding surfaces 42 for the breech . mechanism 1 (casing 18 and lugs 13) as well as for' the substantially equal to the diameter D of the breech mechanism, these . guiding surfaces 42 being situated; on a cylinder of revolution about an axis parallel to the axis X-X of the barrel 16 and generally coincident . with thi3 axis X-X. The trace of this cyclinder on the plane of Figure 4 is coincident with the exterior-' ■ contour of the casing 18 which is also the exterior contour of the spring 10. · , - According. to an advantageous embodiment, the part of substantially rectangular croas-section 3-6 of the breechcase 2 is extended towards the front by a part 43 whose, interior and - exterior cross-sections are cylinders •■of revolutioni'.about the axis X-X of the barrel 16;' the" ' jpart 43 receives the sleeve 15 to which the barrel 16 is fixed in a removable manner; the annular space ' . left free between the exterior of the sleeve .15 and the interior of the cyclindrical part 43 of the- breechcase , 2 houses the control devices (ive. the motor member, ■' compression springs and guides) of the feed mechanisms 9, (vihich control devices will be described hereinunder) , ' the damping devices for the recoil and the return to firing position and. he breech mechanism unlocking device with. its push-piece 27.

The passage 7 and the openings 8 extend towards the front to the front end of the sides 3, 5 and 6..

The small side 4 is approximately tangential to'the-. cylindrical part 43. This part and the. elements of ; each large side an 6 that exists on both sides ·. (in the transverse direction) of the openings 8 are connected among themselves by transverse partitions 61 that render the breechcase 2 rigid and assure its fluid-tightness. ' It is supposed in the following that the breechcase .2 is fixed and that the unit formed by the sleeve 15. and the barrel 16 can recoil with respect to this breechcase in the interior of which it is. guided. The damping devices for the recoil and for the return to' firing position can be. of. two types, mechanical and hydraulic. The mechanical damping 1 devices , which are five in number in the embodiment represented, each comprise a helical sprin 44, coiled around a telesco-: . pic -guide 45 parallel to the axis X-X of the barrel 16, which bears, at the front, against a collar 46 integral with the sleeve 15, and at the rear, against a ring 47 ' rigid with the breechcase 2. This ring 47 can be jr' maintained against a shoulder 48 of the breechcase not only by the springs 44 but also by' rods 49 fixed - . by one end to this ring, passing freely through the collar 46 and bearing by the other end on a nut 50 screwed on the front of the breechcase 2. The hydrau c damping devices, which are two in number in the em-'. bodiment represented, comprise- oil dash-pots each comprising a, cylinder 51 coupled to the ring 47 and : 'a piston whose piston-rod 5 is coupled to the collar " 46, although of course' the pistons and cylinders can be interchanged.

The unlocking device, with its push-piece 27, • ... - . - * -fo the. breech mechanism 1 can comprise a cylinder , ■ .·.. 53, backed. onto the collar 46, and, a 'piston or plunger; 4 rigid with the push-piece 27. The cylinder 53 is conne'cted by a conduit 55, comprising a throttle de- ■ vice 56 (that is to say a body traversed by a channel whose cross-section permits the regulation of the ' operation of ^ the device by constriction of the gases), to a zone of the barrel 16 situated at a certain distance from the cartridge, chamber 57. _The unit formed by 1she push-piece 27 and the piston or plunger 54 is -returned towards the front by a spring 58, the. push-., piece 27 and this spring passing through the ring 47 through an opening visible at. the bottom of' Figure 1^..

In^he annular space left free between the ex- · terior of the sleeve 15 and the interior of the cylindrical part 43, the damping devices for the recoil., and for the return to firing position and the unlocking device for the breech mechanism 1 can occupy the lower sector,' as shown in Figure 3, the unlockin ^, device being advantageously placed in a manner to separate these damping devices into two approximately · symmetrical groups. In the space in question,' a guiding key 59 (Fig. 3) can be disposed, rivetted to the breechcase 2, and lying without play i'n grooves which pass through the collar 46 and the ring 47.·'" ' parallel to the axis X-X thus preventing them from rotating about 'this axis. In particular, it will be. understood that at the firing of a.round, the starting of the of the projectile, by penetration, of the helical lands of the barrel 16 into the driving- band of the projectile, generates, . by reaction, in the uni formed by the. barrel and the sleeve 15» a torque which is absorbed by the key 59 , which prevents this unit from rotating in the interior of the breechcase 2.

To the rear of the introduction openings 8, the large sides 5 and 6 of the part of substantially rectangular cross-section of the breechcase 2 are closed by co-axial curved parts 60 whose interior diameter is equal to the diameter D of the breech mechanism 1 and which "are adapted to render the breechcase 2 fluidtight and rigid, while guidin the breech mechanism 1 and the counter-recoil spring 10. In Figure 4, the central zone of the curved parts 60 can be seen through an opening 62 in the transverse partitions 61, the interior contour of these parts 60 being coincident with the exterior contour of the casing 18 (which is also the exterior contour of the spring 10).

The interior width indicated by the arrow between the large sides 5 arid 6, is larger than the maximum diameter of the cartridge cases (so that these cartridge cases can pass through the passage 7) and smaller than the diameter D of the breech mechanism (to permit the curved parts 60 to be fitted iri' place) .

The. curved parts 60 are extended at the rear, beyond the part of substantially rectangular section 3-6, by two cylindrical sectiors 63 provided with bayonet lugs 64 and adapted to receive a closing block 65 which serves as a support for the counter-recoil spring 10 and contains the damping device 19 of the breech mechanism. In addition to a cylindrical part 65a which fits partially on the sect^or 63, and a back which is The mechanisms 9 are coupled by a fork 74 guided oh the small side 3 in a manner that it can slide transversel with respect to the fire-arm. The fork 74 has slots 75 which each co-operate with a catch 76 rigid with the feed mechanism being considered. A slider 77, guided longitudinally on the small side 3, actuates a lever 78 which is carried by a spindle 79 passing through the slider through an elongated slot. This lever has a head 78a, in the form of a dovetail, which is engaged in a mortise 74a of the fork 74o When the gunner displaces the slider 77 longitudinally in one direction or the other, it rocks the lever 78 about the spindle 79 and displaces the fork 74 transversely (toward the left of Figure 4 if the position shown is the starting position), which puts out of action the feed mechanism 9 (at the left of Figure 4) which was in firing position and puts in action the other feed mechanism, by rocking about the rod 69.

• Each feed mechanism 9 has a mechanism for belt advancement and for motion transmission housed. in the casing 82 of the feed mechanism and a driving member in the form of a roller 85 which is itself adapted to be displaced in a dire ction substantially parallel to the axis X-X of the barrel 16 of the fire-arm. According to the embodiment represented in Figure 2, the belt advancement mechanism comprises cartridge-pushing pawls 80 and the motion transmission mechanism for transmitting motion to' these pawls is comprised by a lever 81 adapted to pivot about a spindle 83 and having a driving projection 84. The advancement mechanism can be of any type, for example as described in British Paten No. 63,119. „ Furthermore, the driving member of the feed mechanism comprised, by the roller 85 is carried by one of the arms of a j two-armed lever 86. The other arm of this lever carries a second roller 87 situated in the trajectory of the projection 84, the lever 86 pivoting about a spindle 88 parallel to the spindle 83. The arm of the lever 86· that carries- the roller 85 is oriented in a manner such that this roller • describes a circular arc the length of which is so small relative to the radius of the arc that said arc is practically identical with a straight line parallel to the axis X-X. It can be seen that, if the roller 85 is pushed to- wards the right of Figure 2 V, it makes the lever 86, rock i the direction which raises the roller 87 with respect to the ' plane of Figure 2, which makes the lever 81 rock in a manner such that its free end is displaced in the same direction.

At least one spring (not shown) assures the return of the levers 81 and 86 by maintaining the roller 87 in contact with the projection 84.

For two such feed mechanisms, as set forth in our , ' Patent Specification No.26168/69 Serial No. 1200848, the fire- .' arm comprises a single motor member in the form of a fork 89 having alternating longitudinal movement and connected to a . recoiling part of the fire-arm, this motor member having a . form and a position such that it meets, during its active or ■■' recoil movement, only the driving member 85 of the · feed mechanism 9 that is. in firing' position.

According to a particular advantageous embodiment, the motor member which has the form of the fork 89 has a base 89a ' which is oriented towards the front and cooperates with · longitudinal guiding surfaces and also has two branches 89b which cooperate by their rear part respectively with the driving members or rollers 85 of the feed mechanisms » The fork 89 has a transverse portion 89c interconnecting the base 89a and the branches 89b. In each casing 82, a passage 90 is provided opposite the roller 85 for the corresponding branch 89b, It can be seen in Figure 4 that the right feed mechanism, which is out of action, has ite passage 90 out of ■ the trajectory of the corresponding branch 89b, this branch passing freely into a notch 91 formed in the casing 82» On the contrary, the feed mechanism visible at the left -of· Figure. 4, which is in action, has its passage 90 just opposite the ^corresponding branch 89b, such that only this branch meets jthe roller 85 that is associated with it and can thus actu- ate the feed mechanism 9 that is in action.

It has been explained above that the control devices of the feed mechanisms 9 are placed, with other members, in the annular space left £ree. between the exterior of the sleeve. and the interior of the cylindrical part 43 of the breechcase 2. These control devices comprise essentially the fork 89, whose traneverse portion 89c is curved to conform to the sector of the annular space that it occupies (see Figure 3..), as well as compression springs (with their guides) which are described . hereinunder.

As it has just been explained, the sleeve 15 essentially "forms with the barrel 16 the recoiling part of the firearm whose, breechca-Je 2 is fixed. The fork 89 is guided at the front by the collar 46 forming a part of the sleeve 15, due to a notch 92 through. which the front end of the base 89a passes.' without appreciable lateral play. The front end of the base 89a can be maintained radially against the bottom of. this notch by contact with the interior wall of the cylindrical part 45 of the breechcase 2, as can be seen at the top of Figure 1. Further more the fork 89 is guided at the rear by a member fixed with respect to the breechcase 2, this member being advantageously comprised by the ring 47. For this purpose, this ring can comprise a bore 93 parallel to the axix. X-X and adapted to guide an extension 89d of the base 89a, situated towards the rea beyond the transverse portion 89:c. The ring 47 furthermore comprises a central bore 98 for guiding the rear of the sleeve 15· The base 89a carries a shoulder 89e adapted to co-operate by abutment with the rear face of the collar.46 of the sleeve 15.· . Between the fork 89 and the collar 46 acts at least one compression spring adapted to make the fork recoil with respect to the breechcase 2, abutment means being provided for bringing back the fork into firing position during the forward return of the recoiling part 15, 16 of the fire-arm.

As can be seen in Figures 2 and 3» two compression springs 94, each wound around a telescopic guide.95 parallel to the axis X-X, are disposed on both sides of the base 89a, these springs bearing at the rear against the transverse portion 89c of the fork.

The abutment means for. bringing back the fork into firing position comprise a double shoulder 96 provided at. the- end of the base 89a, in front of the collar 46 and adapted to abut against the front face of this collar.

Figure 3 shows that in front of the transverse portion 89c the annular space defined hereabove receives the base 89a, four springs 94 with their guides 95 » two hydraulic ' damping devices 51 and 52 , five mechanical damping devices 44 and 45 , and the unlocking device 53 and 54 for the breech mechanism. To the rear of the transverse portion 89c , the springs 94 with their guides 95 are absent and the base 89a is replaced by the branches 89b and the extension 89d „ .t The interior of the base - 89a of the fork can be in the form of a cylinder forming part of a dash-pot regulator for regulating the recoil speed of the fork, this recoil being accompanied by the relaxtion of the springs 94. For this purpose,, the base 89a is provided with a bore 97 , parallel to the axis X-X, in which two pistons 99 and 100 can . slide and are mounted one behind the other, with a certain axial play, on a rod 101. This rod passes in a liquid-tight manner rear-wardly through the bottom of the cylinder formed by the bore ' 97 and bears against a stop 102 rigid with the breechcase 2 , ' An annular sealing ring 103 , disposed in a slidable manner about the rod 101, is pushed by a spring 104 towards the two — pistons 99 and 100,'^and the space situated . in the bore 97, . n front of the sealing ring 103 is filled with oil. It ca be seen thatirthe spring 104 has the effect of maintaining in this space. a pressure sufficient to push the rod 101 into contact with the stop 102 and permits, moreover:,;, the sealing ring 103 to be displaced to compensate for>the variations of volume of -this space which are due to the larger or smaller penetration of the rod 101. Between the front piston 100 and the bore 97 , play is provided which normally assures a constant speed of recoil of the fork 89 by passage of the οίϊ from the front to the rear of this piston. The piston 99 carries elastic rings 1.05 which tend to separate the piston 100 from the piston 99, some of said rings' being located within a skirt on the piston ... 99. The piston 100 has channels 106 passing therethrough adapted to be blocked off by the neighbouring face of the piston 99· when the rings 105 are compressed and the skirt of the piston 99 is in contact with the piston 100. It can be Been that, if the ' speed of recoil of the fork 89 (towards the right of Figure 1) increases, the pressure prevailing in front (to the left) of the piston 100 increases and the piston compresses the rings 105 and comes into contact with the skirt of the piston 99. This closes the channels 106 and the oil can only pass through the annular play provided at the periphery of the piston 100. The recoil of tthe fork 89 is thus well braked whereas its advance is not braked, in particular by reason of therione-way action between the rod 101 and the stop 102.

The lever 86 for motion transmission between the fork 89 and each feed mechanism 9 is housed in the case 82 which is connected directly to the breechcase 2 whereas the lever :81 and the pawls 80, for the advance of the belt, are housed in the cover 71. The spindle 88 of the lever 86 is thus fixed to the casing, 82 in which the passage 90 is formed, whereas the spindle 83 of the . lever 81 is fixed to the cover 71. It will be understood that the coupling, by the projection 84 and the roller 87, between the two levers 86 and 81 permits opening and closing of the cover 71» for the transverse introduction of the cartridge belt, without ; any particular precaution.

Advantageously, the breech mechanism is arranged in a manner such that the rear of the motor member or fork 89,. in th ■ 39860/2 - 18 - rest position illustrated in Figure 2, is located in front of the front face of the feed mechanlsme. I other words, when the sleeve 15 is In its most forward position and when the shoulder 96 of the fork 89 is in abutment with the collar 46, the rear end of the one of the "branches 89b that is located opposite a roller 85 does not penetrate into the corresponding passage 90.

This p era-its the two feed mechanisms 9 to be rocked In e manner described above without the branches 89b of the fork 89 hindering this manoeuvre* In the foregoing, a fire-arm has been described comprising in the interior of a breechcase 2, on the one hand, a sleeve 15 to which the barrel 16 of the fire-arm is fixed in a removable manner by a bayonet joint 17, and on the other hand> a nut 50 which is screwed on the front o the breechcase 2 and which serves to maintain the sleeve 15 in the longitudinal direction towards the fron and in the transverse direction at the same time, conduit 55 and throttle device 56, being provided between the part of the barrel 16 situated at the fron of the nut 50 and a zone situated at the rear of the sleeve 15 between this sleeve and the breechcase 2.

In this fire-arm, the sleeve 15 is adapted to recoil with the barrel 16 with respect οψ the breechcase 2 and is guided in translation by the nut 50. The sleeve 15 has two successive collars, namely a front collar 107» whose diameter is equal to the interior diameter of the, nut 50 and which is disposed in the interior of the nut whereby the sleeve 15 is maintained transversely with respect to the nut (with sliding, according to the embodiment represented), and a rear collar whose diameter, greater than the diameter of the front collar 107, is equal to the interior diameter of the breechcase 2 and which is disposed to the rear of the nut 50 whereby forward movement of the sleeve 15 is limited by the nut 50 ( by abutment ) , and the sleeve 15 is maintained transversely (with sliding) with respect to the breechcase 2. Preferably, this rear collar is the collar 46. Moreover, the interior diameter of the nut 50 is chosen sufficiently large (in other words, the radial thickness of this nut sufficiently small) to permit, in this case, the throttle device 56 to pass through the front ; collar 107 without touching the nut 50.

The sleeve 15 is thus guided, at the front, by contact with the interior surfaces of the nut 50 (collar 107) and of the breechcase 2 (collar 46), and at the rear, by contact with, the bore 98 of the ring 47» Its movement towards the front is limited by contact of the front face of its collar 46 with the rear face of the nut 50. A retractable locking device 108, having a ball or the like, prevents the nut from .turning with respect to the breechcase 2.

Due to the arrangement of the nut 50 whioh has just been described, it can be seen that it is possible to screw it or unscrew it, with a view to dismantling or re-assembling the sleeve 15» without preliminary dismantling of the. connectin means and .more particularly, according to the example shown, of the throttle device 56* In the foregoing, an ejection system has been briefly described which comprises an extractor 35. carried by the movable breech mechanism 1, and diametrically opposed, an ejector 33 carried by the breechcase 2 and actuated by the breech mechanism 1, by contact of the tail 33a of the ejector with the projection 25 of the breechblock 11.

More precisely, the ejector 33 comprises at the front a transverse striking surface 109 (Figures 1 and 5) for the; rear edge of the empty oartridge case 110 to be ejected and it is controlled by the breech mechanism in the usual manner such that it presents the striking surface 109 into the trajectory uria υ* -: the ejec or compr ses, at t e ron o the striking surface 109, a projection 112 adapted to strike the lateral surface of the cartridge case 110 transversely, before the impact with the rear edge of the cartridge case.

Figure 5 shows the cartridge case 110 which, still maintained at the top by the extractor 35 after having been struck by the projection 112, hae begun its tipping movement in the direction of the. ejection passage ,7. It is only then that the striking surface 109 hits the rear edge of the cartridge case with a relative speed which is decreased by the forward speed imposed on the part of this edge that the surface 109 strikes. In this manner, the violence of the impaot is decreased and the ejection trajectory is stabilized.

The operation of the fire-arm described above is the following.

When a cartridge is placed in the chamber 57 and when . the breach mechanism arrives in the position of Figures 1 and 2, the cartridge is fired, which causes the recoil of the unit formed by the barrel 16, the sleeve 15 and the breach mechanism 1 By the rear of the collar 46 of the sleeve 15» the recoil damping springs 44 and the control springs 94 of the feed mechanisms are compressed and the pistons of the reooil dampers 51 and 52 are driven towards the rear. The springs^ 94 drive the fork 89 towards the rear with a speed regularized by the dash-pot 97 and 99-105» whatever be the resistance to the traction of the belt in the one of the two feed mechanisms 9 that is in firing position. According to the stroke of reooil of the fire-arm, the collar 46 of the sleeve 15 abuts 6r does not abut against the shoulder 89e of the fork 89. B one of its branches 89b which meets a roller 85» the fork makes the levers 86 and 81 of the feed mechanism in firing position pivot, which puts a cartridge in position for introduction.

When the bullet has passed the gas. inlet Of the conduit 55» the gases pass through the throttle device 56, penetrate into the unlooking cylinder 53 and act on the front face of the piston or plunger 54. This piston or plunger 54 compresses the spring 58 and drives the breech mechanism casing 18 in an accelerated movement. The casing 18» while recoiling, makes the breechblock 11 rotate in a manner' such tha it frees itaelf from the sleeve 15. The residual pressure of the gases in the chamber 57 contributes to make · the breechblock 11 recoil, which it does while compression the counter-recoil spring 10, the breechblock 11 finally abutting at the. end of its stroke against the damping device 19 At the same time, the empty cartridge case is ejected in the manner described above.

, The breech mechanism is then returned towards the front by the damping device 19 and the counter-recoil spring 10 drives the cartridge that was in position for introduction and introduces it into the chamber 57. The casing 18, which had been maintained at the rear of the breechblock 11 b the leaf- Ί spring 38 during the reciprocation of the breech mechanism, ' I ' . <·»· . I is freed by the action of the inclined surfaoe 40 and the spring 111 drives it towards the front, which, on the one hand, . locks the breechblock 11 by making it rotate and then brings the point of the firing pin 21 into the cup-shaped recess 12. (new percussion).

During the forward return of the ,breeck mechanism, the springs 44 restore their energy while bringing back towards the front the sleeve 15 and the barrel 16. The fork 89 is driven positively towards the front by abutment of the shoulder .96 against the collar .46 and is also driven in this direction '.by the springs 94. The damper 97 and 99-102 is inoperative during this forward stroke , for the reasons explained above (separation of the pistons 99 and 100, absence of positive coupling between the rod 101 and the abutment 102) . On the contrary, however, the dampers 51 and 52 brake the recoil as well as the return of firing position of , he unit formed by the sleeve 15 and the barrel 16.

Such a fire-arm has numerous and real advantages, in particular! - a reduced cumbersomeness, since the two feed mechanisms 9 are disposed on parts of the breech mechanism that are . narrowed to a substantially rectangular cross-section; t ' - a simple putting out of aotio of the retracted feed mechanism, since it depends only on the position bf this feed mechanism; . ; · - a gain of energy in the driving of the feed mechanism since the only members in motion are those which .. transmit directly the recoil energy to this feed mechanism; - a great safety of operation due to the fact that, all the moving members are housed in the interior of a fluid-tight breechcase. . r—--

Claims (3)

1.: A semi-automatic or automatic fire-arm having two feed mechanisms articulated on the breeohcase one on each side thereof and controlled so that one of them is in firing position when, the other is out of firing position and vice-versa, each feed mechanism having a mechanism for advancing cartridges, a mechanism for transmitting motion to the advancing mechanism housed in the feed mechanism and a driving member which is Itself adapted to be displaced in a direction substantially parallel to the axis of the barrel of the fire-arm, characterized by the fact that the fire-arm comprises for the two feed mechanisms a single motor member having alternating longitudinal motion, connected to a recoiling part of the fire-arm and of form and position such that it meets, during its recoil motion, only the driving member of the feed mechanism that is in firing position.

2. A fire-arm according to Claim 1, characterized by the fact that the motor member has the form of a fork whose base is oriented towards the front and cooperates with longitudinal guiding surfaces and whose branches cooperate by their rear part respectively with said driving members of the feed mechanismst

3. A fire-arm according to Claim 2, characterized by the fact that the fork is housed in the annular space limited by the exterior of a sleeve which carries the barrel and forms with the latter essentially the recoiling part of the fire-arm and by the interior of a cylindrical part of the breeohcase, this fork being guided at the front by a collar forming part of the sleeve and at the rear by a member fixed with respect 4, A fire-arm according to Claim 3» characterized by the fact tha between th? fork and the collar acts at least one compression spring adapted to make the fork recoil with respect to the breechcase, abutment means provided for bringing the fork back into firing position during the orward return of the recoiling part of the firerarm. 5, A fire-arm according to Claim 4, characterized by the fact that the interior of the base of the fork is in the form of a cylinder forming part of a dash-pot for regulating the recoil speed of the fork. 6, A fire-arm according to Claim 5, characterized by the fact that the motion transmission' mechanism is housed in the part of the feed mechanism which is directly connected to the breechcase whereas the belt advancement mechanism is housed in a cover which is fixed to said part of the feed mechanism in a manner to be able to be separated from it for the transverse introduction of a cartridge belt* 7·., A fire-arm according to any preceding claim characterized by the fact that the rear of. the motor member, or fork, in the rest position is located in front of the front face of the feed mechanisms in a manner to permit the movement into firing position of the feed mechanisms. For the Applicants DR«,,,,REINH01D CGHN AND PARTNERS Byt