US2924150A - Indirect cartridge feed mechanisms of the rotor type for sliding breech automatic guns - Google Patents

Description

Feb. 9, 1960 B. MAILLARD INDIRECT CARTRIDGE FEED MECHANISMS OF THE ROTOR TYPE Foa SLIDING BREECH AUTOMATIC GUNS 3 Sheets-Sheet l Filed May 16, 1955 www N No /x A N M Y 55 l virili/l IIIIVHIIIIIlllllvllllllllll ATTDHNEY Feb. 9, 1960 B. MAILLARD 2,924,150

INDIRECT CARTRIDGE FEED MEcHANIsMs oF THE RoToR TYPE FOR sLIDING BREECH AUTOMATIC GUNS Filed llay 16. 1955 3 Sheets-Sheet 2 cata/az Macul@ ATTHNEY Feb. 9, 1960 B. MAILLARD 2,924,150

INDIRECT CARTRIDGE FEED MECHANISMS OF THE ROTOR TYPE FOR SLIDING BREECH AUTOMATIC GUNS 3 Sheets-Sheet 3 Filed May 16, 1955 United States Patent O INDIRECT CARTRIDGE FEED MECHANISMS OF THE ROTOR TYPE FOR SLIDING BREECH AUTOMATIC GUNS Bernard Maillard, Geneva, Switzerland, assignor to Brevets Aero-Mecaniques S.A., Geneva, Switzerland, a Swiss society The present invention relates to indirect cartridge feed 5 mechanisms of the rotor type for sliding breech automatic guns.

The term sliding breech automatic gun designates a gun including a part, which will be supposed to be a breech-block proper, having a reciprocating displacement every time a shot is red. The firing cycle being supposed to begin when the shot is just being fired, the breech-block first recoils under the next cartridge to be fired, which is in waiting position, until, after a suicient rearward displacement of said breech-block, said cartridge can move down to its introduction position, where it rests upon the edges of the feed passage, and from which it is pushed frontwardly by the breech-block, during the frontward return movement thereof, into the cartridge chamber of the gun barrel.

'Ihe term indirect cartridge feed mechanism of the rotor type designates any mechanism for moving a plurality of cartridges disposed side by side in a row (and kept in this formation by resilient holding strips carried either by links when the row of cartridges forms a cartridge belt or by clips each of which forms such a row) so` as to move this plurality of cartridges transversely toward the breech mechanism during firing, by means of a driving toothed rotor the teeth of which engage between the cartridges of the downstream end of a row (the term downstream applying to the portion of the row of cartridges which is nearer the breech mechanism), this rotor being actuated by a power mechanism, every cartridge, upon leaving said rotor having a complementary transverse displacement to come into its introduction position.

Generally, the power mechanism for driving the rotor is operated by energy supplied by the recoil movement of the gun, or of a portion thereof.

Up to the present time, the rotor of a cartridge feed mechanism of such a type directly exerted on the one hand the pull on the row of cartridges necessary to produce its feed displacement and to extract the cartridges from their resilient holding strips, and on the other hand the thrust necessary to impart to the car- 5 tridges already separated from the above mentioned row the above mentioned complementary transverse displacement.

Now, this complementary displacement includes two distinct steps for every cartridge.

The first of these steps consists in shifting the cartridge from the driving rotor to the waiting position of said cartridge on the top of the breech-block.

'Ihe second step consists in shifting the cartridge from this waiting position to its introduction position as above defined.

These two successive movements must take place at two different times respectively, the cartridge remaining stationary between these two steps. Up to the present time, these steps were produced directly by the thrust of the rotor in mesh with a row of cartridges, so that ice said row of cartridges was set in movement then stopped, then again set in movement and once more stopped, for every shot being red. The row of cartridges therefore underwent, at very short time intervals and at a rate equal to twice the rate of firing of the gun, very high accelerations and decelerations.

On the other hand, since the torque transmitted to the rotor was directly transformed into a thrust exerted on the successive cartridges for giving them their complementary displacement and since this torque had to be chosen sufficiently high to be able to enable the rotor to perform its other functions, that is to say in particular that of pulling the cartridges from their resilient holding strips (which exert a relatively high resistance), the thrust exerted on the successive cartridges for imparting thereto their complementary transverse displacements was generally much too great. This caused, at some times during the tiring cycle, considerable frictions between the cartridge on the one hand and either the top of the breech-block or the edges of the feed passage on the other hand.

'Ihe object of the present invention is to provide a cartridge feed mechanism of the above mentioned type which is free from these drawbacks and which makes it possible in particular to obtain higher rates of re than those used up to the present time.

According to the essential feature of this invention, the means for controlling the rotary displacement of the driving rotor on every firing of a shot are arranged to permit this rotary displacement to take place wholly without interruption, that is to say without meeting any positive abutment capable of stopping it temporarily before the end of said movement, and a thrust member subjected to the action of a spring tensioned every time a shot is tired by said rotor during at least the end portion of its rotary displacement is provided for subsequently producing at least most of the transverse complementary displacement of the next cartridge to be introduced into the gun barrel.

Other features of the present invention will become apparent in the course of the following description with reference to the appended drawings, given merely by way of example and in which:

Fig. l is a diagrammatic elevational view of an automatic gun provided with a cartridge feed mechanism according to the present invention.

Fig. 2 is a partial view in perspective, with portions cut away, of a cartridge feed mechanism of the rotor type made according to the present invention.

Fig. 3 is a part sectional view, on an enlarged scale, of a portion of said feed mechanism.

Figs. 4 to 7 inclusive are part sectional views on the line IV-IV of Fig. 3 showing elements of the feed mechanism in four different relative positions.

Fig. 8 is an explanatory diagram.

The automatic gun shown by the drawings includes a barrel 1 rigid at the rear with a breech case 2 in which reciprocates a breech-block 3 urged frontwardly by a recuperator spring 4 and release of which is controlled by a gas tap system 5.

The whole of these elements, which constitutes the gun proper, is slidable in a fixed support or cradle 6, an elastic system 7 being interposed to absorb the recoil of the gun with respect to said cradle and to return it frontwardly.

Rigid with support 6 there is provided a plate 8 (magazine ca rrier) intended to receive the cartridge feed mechanism 9 which will be hereinafter described. For instance, as shown, this plate 8 is linked to support 6 by -an arm 10 and the upper edge of the breech case slides on the under face of said plate during the reciprocating movement of the gun.

Patented Feb. 9, 1960 Plate 8 is provided with means for securing the eartridge feed mechanism thereto in a detachable manner, such means being for instance constituted at the front end by a tenon-and-mortise connection 11 and, at the rear, by a retractable locking finger 12.

The cartridge feed mechanism is operated by energy supplied by the gun during a portion (hereinafter called active portion) of its recoil movement with respect to its cradle and to plate 8 rigid with said cradle, said feed mechanism being provided for this purpose with a transmission interposed between the gun proper and the row of cartridges which is moved forward a distance equal to one pitch every time a shot is fired.

This transmission is for instance made, according to a known arrangement, as illustrated by Figs. 2 and 3.

The breech casing 2 of the gun carries a cam 13 mounted to oscillate about a pin 14 at right angles to the upper face of said breech casing on a support 15 fixed on said upper face.

This cam 13 is arranged in such manner that when the gun is recoiling, said cam is engaged in Wedge-like fashion between a fixed abutment constituted by a roller 16 and a push-piece 17 provided with a roller 18 and slidable transversely against the action of a return spring 19. Said roller 16 and said push-piece 17 are housed in the front portion of casing which, as above stated, remains stationary during the recoil movement of the gun.

Push-piece 17 carries a rack 20 adapted to mesh with a toothed sector 21 rigid with a tubular sleeve 22 which carries the driving portion 23 of a free wheel (including for instance rollers 24) the driven portion 25 of which carries teeth 26 cooperating with a pawl 27 which permits rotation of said driven portion only in one direction.

This driven portion 25 of the free wheel is rigid with the driving element 28 of a dog clutch the driven element 29 of which (applied against element 28 by a resilient device such for instance as a stack of washers 30) is coupled in rotation, for instance by means of splines, with a hollow shaft 31 coaxial with tubular sleeve 22 and located on the inside thereof.

The left hand end of this hollow shaft 31 is coupled, for instance by means of splines, with one end of a torsion bar 32 the other end of which is similarly coupled in rotation with a hollow tubular shaft 33 which carries the toothed wheels 34 of a conventional rotor for driving the cartridge belt.

The left hand end of shaft 33 is connected with the right hand end of hollow shaft 31 through a lost motion coupling device 35 including straight teeth engaged in one another with an angular play of an amplitude smaller than one pitch and which, in a very satisfactory embodiment of the present invention, where the rotor includes ten teeth (the pitch being then equal to 36 of rotation of the rotor) is about 30.

It will be understood that, with such a transmission, shaft 31 is given, at the beginning of every ring cycle, during the active portion of the recoil movement of the gun, a rotary displacement equal to one pitch, which is transmitted to shaft 33 and therefore to the rotor, as it will be hereinafter explained.

Fig. 8 shows a curve, time being plotted in abscissas and in ordinates the displacements of the gun proper for curve A and of the breech-block for curve B. The whole of a firing cycle is designated by C, and D indicates the zone corresponding to the active portion of the recoil movement of the gun.

According to the present invention, the cartridge feed mechanism, made as above described or in an equivalent fashion, is arranged in such manner that, on every firing cycle, the rotary displacement of the rotor equal to a full pitch takes place in an uninterrupted manner, that is to say without said rotor being temporarily stopped by a positive abutment, said rotor, during this rotary movement, pulling the cartridges from the holding resilient strips by means of which the cartridges of a row are mounted on a common support, the complementary transversed displacement of the next cartridge to be introduced into the gun barrel being achieved at least partly by a thrust member pushed back by a spring which is tensioned every time a shot is fired, preferably during at least the last portion of the immediately preceding rotary displacement equal to one pitch of the rotor mounted on shaft 33.

For this purpose, the feed mechanism is made for instance as follows:

Fixed guides 36 in the form of circular arcs (Figs. 4 to 6) are provided to prevent the cartridges 37 from moving radially away from the rotor after said cartridges have been inserted between the teeth of said rotor and as long as they have not reached the radial passage 38 through which said cartridges are subsequently moved toward the edges 39 of the feed passage.

As the support of the row of cartridges is guided so as to slide along a straight line, the cartridges are successively pulled away from the resilient holding strips carried by said support, due to the rotation of the rotor.

The elements of the cartridge feed mechanism cooperating with the rotor and also passage 38 are made and dimensioned in such manner that while, during the active portion of the recoil movement of the gun, shaft 31 is given the rotary displacement equal to one pitch which must take place every time a shot is fired, shaft 33 and therefore the wheels 34 of the rotor are able to follow this rotary movement, with possibly an angular offsetting which produces a damping effect, permitted by the play existing between the teeth of the lost motion coupling device 35 owing to the preliminary tensioning of the torsion bar 32.

For this purpose, no positive abutment must take place which would temporarily stop the rotation of the rotor while it is moving through an angle corresponding to one pitch. Furthermore, passage 38 must have a given height as it will result from the following explanations.

A suitable number (for instance a pair) of thrust cams or oscillating deectors 40 are mounted freely rotatable on shaft 33. Thus if, as shown by Fig. 3, the rotor includes three toothed wheels 34, the front wheel meshing with the projectile, the middle wheel with the front end of the cartridge case and the rear wheel with the rear potrion of said cartridge case, a first cam 40 is disposed between the second and the third wheels 34 and another cam 40 rearward of the third wheel 34. Anyway, all these cams 40 must act simultaneously and inidentical fashion on the same cartridge and therefore their outlines will be suitably determined on account of the diameter and the position of the portion of the cartridge with which each of them cooperates.

A spring 41 having one end fixed at 42 to the body of the feed mechanism is connected at the other end to each of these cams 40 so as yieldingly to oppose rotation of said cam in the direction of rotation of the rotor. An abutment 43, carried by the fixed portion of the mechanism, limits the displacements of cams 40 under the effect of springs 41.

Cams such as 40 are already known in the art. But the cams according to the present invention differentiate from those used up to this time, on the one hand by the fact that they cooperate with a rotor which meets no positive abutment capable of temporarily stopping it as it is rotating through an angle equal to one pitch every time a shot is iired, and on the other hand, by the fact that their free ends are so shaped that they can operate as it will now be described.

The cycle of operations corresponding to the firing of one shot being considered as starting just when one cartridge is fired, Fig. 4 shows at this time the position of cams 40, of the rotor and of the last cartridges a, b and c which have not yet been tired.

The rotor is stationary and no torque is then exerted thereon. Cams 40 are inoperative and in contact with their abutments 43. The next cartridge to be introduced into the gun barrel, to wit a, is in passage 38. It has already escaped radially from the rotor. Breech-block 3 is in its frontward position. On the diagram of Pig. 8, this corresponds to the origin, that is to say point O.

As soon as the shot is fired, the gun (curve A) and the breech-block (curve B) start recoiling with diterent movements respectively. Nearly immediately after this, i.e. at point I, torsion bar 32 begins to be twisted and this lasts as far as point II, which corresponds to the end of the active portion of the recoil movement of the gun.

As soon as shaft 31 begins to be rotated, the rotor also starts rotating. Cartridge a is not influenced, whereas cartridges b and c are moved forward and pass from the position of Fig. 4 to the position of Fig. 5 (point III of curve B). But it should should be noted that, a very short time after the beginning of its frontward movement, cartridge b (rst cartridge), which is still in mesh with thelrotor, comes into contact with the active edges of cams 40 and starts pushing said cams in the direction of rotation of the rotor against the action of springs 41.

The rotation of the rotor through an angle equal to one pitch takes place without interruption and is ended, as shown on Fig. 6, before the breech-block has come to the position marked by point IV on curve B, which point corresponds to breech-block 3 retracting rearwardly from under cartridge a. When the rotor stops, springs 41 are tensioned at the maximum and, due to a suitable obliquity given to the active edges of cams 40, said springs 41 cause the rst cartridge b to be caught between said cams 40 and the teeth of wheels 34 so that a relatively high resultant radial thrust is exerted on said cartridge (Fig. 6). This radial thrust is transmitted to cartridge a and applies it against the top of the breech-block.

As soon as the breech-block has moved past point IV of curve B, that is to say has moved from under cartridge b, the above mentioned radial thrust causes cartridge a to move down suddenly so as to be applied upon edges 39 as shown on Fig. 7. During the downward movement of cartridges a and b, the rotor has remained stationary but cams 40 have been given by springs 41 a sudden rearward movement, i.e. a movement in the direction opposed to that in which the rotor was previously moving.

When breech-block 3, in the course of its return stroke toward the front, comes into contact with cartridge a (point V of curve B), it drives said cartridge toward the gun barrel cartridge chamber. At least one of the cams 40 is still exerting a thrust on the rst cartridge b and this thrust starts the downward movement of cartridge b as soon as (point VI of curve B) cartridge a has been retracted from under said cartridge b and has left it free to move down toward the top of the breech-block as shown on Fig. 4. The next ring cycle is then ready to begin.

The above explanations clearly show the distinct functions played by the rotor and by cams 40. The rotor drives the cartridges which are in mesh therewith and therefore the row of cartridges carried by a support such as S. It also tensions springs 41. But these cams 40 are the only elements which ensure the subsequent transverse displacement in two steps of every cartridge from the rotor toward edges 39. Therefore the rotor is not caused, as in the devices known to this time, to stop suddenly during its displacements due to the positive abutment caused by contact between the last cartridges when the next cartridge to be introduced into the gun barrel is applied against the top of the breech-block.

Of course, the shape of the active edges of cams 40 may, in every particular case, be easily determined by anyone skilled in the art, in view of the above explanations. Advantageously, these active edges include two portions, both oblique with respect to a radial line, the upstream portion (i.e. that on the left on Figs. 4 to 7) being, as shown on the drawings, at a more acute angle to the radial direction than the downstream portion.

Preferably, and in particular when the cartridges are relatively heavy (for instance for projectiles of a caliber higher than 25 mm.) the system will further include a supplementary braking cam 44. This cam is analogous to cams 40 and it is similarly urged in the rearward direction by a spring 45, the displacements of cam 44 being limited, in the direction of rotation of the rotor, by an abutment 46 and in the opposed drection, by an abutment 47 (which is advantageously carried by the right hand wall of passage 38).

Cam 44 is provided with Aan active side adapted to cooperate with the cartridges in mesh with the rotor and which preferably extends in a radial direction. Thus it can exert practically no radial thrust on the cartridge which is applied against this active side. On the contrary, it then exerts on this cartridge (cartridge b on Fig. 6) a thrust tending to brake the rotary movement of the rotor.

It will be understood that if the active side of cam 44 and also abutment 47 are suitably located, the irst cartridge in mesh with the rotor will come into contact with the active side of said cam 44 before the end of the rotary displacement of the rotor so that said rotor will be elastically braked. As for abutment 46, it will be advantageously disposed, as shown on Fig. 6, in such manner that, once the rotor stopped at the end of its rotary displacement, said abutment positively prevents cam 44 from enabling cartridge b to move frontwardly due to its inertia.

The preceding explanations show that the fact that the transverse displacement of the cartridges is produced by means distinct from those which cause the feed movement of the row of cartridges makes it possible to obtain this feed movement in the best possible conditions and at a velocity dependent upon the inertia of said row of cartridges and therefore of the number of cartridges remaining in this row. Besides, said transverse displacement in two steps is concerned with only a very small number of cartridges (two in the example above described). Therefore this displacement will be produced exclusively by the strength of springs 41 and it is not iniluenced by the variable inertia of the row of car tridges driven by the rotor.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and efficient 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:

l. In a gun having a reciprocating breech block and cartridges for said gun, a cartridge feed mechanism operable by the recoil movement of said gun and comprising a feed passage having a vertical central longitudinal plane extending through the path of travel of said breech block and an inlet end, a cartridge feed chamber to one side of and joining said inlet end, a toothed rotor rotatably mounted adjacent said chamber about an axis substantially coplanar with said central plane'and parallel to said path, a first cam rotatably mounted about said rotor axis, said rotor undergoing a predetermined displacement with each shot, each recess between two of said teeth being adapted to engage one said cartridge and the wall of said chamber being adapted to guide said cartridges in an arcuate path to said inlet end with rotation of said rotor in a first direction toward said central plane, and at the end of Said displacement a rst cartridge disposed in said passage and engaging the horizontal plane of the upper surface of said breech block and a second cartridge engaged in one said recess and positioned with its axis parallel to and disposed to the opposite side of said central plane vfrom said chamber,

said second cartridge also engaging said iirst cartridge in the mouth of said inlet end and a first surface of said first cam, said first cam being urged in a direction opposing said iirst direction and said first surface being in a plane disposed downwardly from said central plane at an angle adapted to thrust said second cartridge toward said iirst cartridge, whereby unobstructed continuous rotation of said rotor is permitted by virtue of said iirst cam acting to thrust said cartridges into said feed passage and the path of said breech block.

2. A cartridge feed mechanism according to claim 1 further comprising a second cam rotatably mounted about said rotor axis, said second cartridge also engaging a second surface of said second cam at the end of said displacement, said second cam being urged in a direction opposing said first direction and said second surface being in a plane disposed substantially parallel to said central plane, whereby the arcuate movement of said second cartridge upon said rotor reaching the end of said displacement is halted by the resilient action of said second cam.

3. In a gun having a reciprocating breech block and cartridges for said gun, a cartridge feed mechanism operable by the recoil movement of said gun and comprising a feed passage having a vertical central longitudinal plane extending through the path of travel of said breech block and an inlet end, a cartridge feed chamber to one side of and joining said inlet end, a toothed rotor rotatably mounted adjacent Said chamber about an axis substantially coplanar with said central 4plane and parallel to said path, a first cam mounted in said gun about an axis adjacent said chamber, said rotor undergoing a predetermined displacement with each shot, each recess between two of said teeth being adapted to engage one said cartridge and the wall of said chamber being adapted to guide said catridges in an arcuate path to said inlet end with rotation of said rotor in a first direction toward said central plane, and at the end of said displacement at least one first cartridge disposed in said passage and en-v gaging the horizontal plane of the upper surface of said breech block and a second cartridge engaged in one said recess and positioned with its axis parallel to and disposed to the opposite side of said central plane from said chamber, said second cartridge also engaging said first cartridge in the mouth of said inlet end and a first surface of said first cam, said first cam being urged in a direction opposing said first direction and said first surface being in a plane disposed downwardly from said central plane at an angle adapted to thrust said second cartridge toward said iirst cartridge, whereby unobstructed continuous rotation of said rotor is permitted by virtue of said 'liirst cam acting to thrust said cartridges into said feed passage and the path of said breech block.

4. A cartridge feed mechanism according to claim 3 further comprising a second cam mounted in said gun about an axis adjacent said chamber, said second car- -tridge also engaging a second surface of said second cam at the end of said displacement, said second cam being urged in a direction opposing said iirst direction and said second surface being in a plane disposed substantially parallel to said central plane, whereby the arcuate fmovement of said second cartridge upon said rotor reachting the end of said displacement is halted by the resilient action of said second cam.

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