IL22933A - Automatic feed mechanism for guns - Google Patents

Description

22933/2 D'nrnn *ο»ι©ικ nam pa*a»s e ^i^atf Improvements in automatic feecl mechanism for guns BIEVBTS AERO- BCAKiQUES 3.A. 0:22012 The present invention relates to guns, and in particular automatic guns, of a caliber ranging preferably from 20 to 50 mm. and to which ammunition is fed through a mechanism automatically actuated by the gun itself.

The invention is more especially, but not exclusively, concerned with guns where the ammunition is carried by a belt actuated by a belt feed mechanism.

The chief object of the present invention is to provide a gun of this type which is better adapted than those existing up to the present time to meet the requirements of practice, in particular concerning the safety of operation of the feed mechanism.

The invention is concerned with guns including a movable breechblock having a reciprocating movement, and a feed device actuated by energy supplied by a resilient energy accumulator periodically receiving energy from a movable portion of the gun other than the breechblock thereof but having a reciprocating movement at the same rate as that of said breechblock, which movable portion may be the whole of the gun when the latter is mounted to recoil, against the action of a buffer system, on a stationary cradle supporting the gun feed device.

According to an essential feature of the present invention, the movable breechblock of the gun is operatively connected in a permanent and continuous fashion with the movable parts of the feed mechanism to be actuated, this connection being effected through a positive transmission mechanism capable of piloting said movable parts in respect to the movements of said breechblock, that is to say through a transmission mechanism positions of said movable parts in accordance with the instantaneous position of the movable breechblock of the gun.

A preferred embodiment of the present invention will be hereinafter described with reference to the appended drawings, given merely by way of example, and in which: Pig.1 is a diagrammatic longitudinal view illustrating the operation of the feed mechanism of a movable breechblock automatic gun; Pig.2 is an end view of some parts illustrated by the diagram of 3?ig,1, certain of said parts being shown in a position rotated at 90° about an axis perpendicular to the plane of the drawings, for the sake of clarity; Pig.3 is a diagram illustrating the operation of the gun.

Automatic gun 1 is adapted to recoil with respect to a cradle 200, with the interposition between them of a buffer spring 201. Gun 1 comprises a breechblock 34 having a reciprocating longitudinal movement. The ammunition feed device, carried by cradle 200, is adapted to be actuated automatically by the gun.

Said feed mechanism comprises a sliding member 143 having a reciprocating transverse movement and provided with pawls 143a adapted to catch the ammunition belt and to move it forward one step for every active stroke of said sliding member 1 3. The strokes of sliding member 143 in the opposed direction produce no displacement of the ammunition belt.

In a known manner, the active strokes of sliding member 1 3 are produced by a resilient energy accumulator carried by cradle 200 and periodically energized, at the rate of firing, by the recoil of gun 1 with respect to its cradle 200.

According to the present invention the sliding member 143 of the feed mechanism is operatively connected with the breechblock 34 of the gun through positive transmission means capable of ensuring a piloting of the movement of sliding member 143 by breechblock 34, that is to say a transmission mechanism such that to every position of breechblock 34 there corresponds a well determined position of sliding member 143.

In other words, owing to such positive transmission means and during the whole of the cycle of operation of the gun, the instantaneous position of sliding member 143 is constantly determined by the instantaneous position of breechblock 34 according to a predetermined law depending upon the characteristics of said transmission mechanism..

It will be understood that it is therefore possible, owing to a suitable arrangement of said mechanism, to obtain the desired law of movement for sliding member 3, this result being obtained without imposing important supplementary stresses to breechblock 34 such as would take place if the energy necessary for ensuring the active strokes of said sliding member 143 were supplied by said breechblock instead of being supplied, as it is the case with the present invention, by a resilient energy accumulator stressed, on every shot that is fired, by the recoil of gun 1 with respect to its cradle 200.

The resilient energy accumulator is made as follows: There is provided, on the side of sliding member 143, a transverse fork 143-e subjected to the action of a compression spring 202 urging said sliding irember 143 in the direction of its active strokes. Said spring 202 bears at one end upon an abutment 203 with trunnions 204 engaged in notches formed in the arms of said fork 143¾. The other end of spring 202 bears against an abutment 205 slidable upon a rod 207 rigid with abutment 203 and acting as guide for said spring 202.

In order periodically to stress spring 202 at the rate of firing, use is made of an oscillating lever 208 pivoting about a pin 209 rigid with the gun cradle 200. One of the arms of this lever 208 is in the form of a fork bearing against trunnions 206 carried by sliding abutment 205. The other end of said lever 208 carries, journalled thereto, a roller 210 opposite which there is provided a roller 211 journalled about an axis fixed with respect to the cradle 200 of the gun. A cam 211 having its end of bevelled shape followed by a portion having parallel sides, mounted on gun 1 , comes, on every recoil movement of the gun, between rollers 210 and 21¾/ so as to produce a displacement of roller 210 and therefore a pivoting of lever 208 having for its effect to compress spring 202.

It should be noted that, if no special precautions were taken a premature return of the gun toward the front would risk clearing the parallel sides of cam, 212 from between rollers 210 and 211 and thus reducing the compression of spring 202 before said spring has transmitted energy to sliding member 143.

In order to avoid this risk, means are provided to act, on every recoil stroke of gun 1, to lock lever 208 temporarily in its maximum rotation position (for which spring 202 is correctly stressed) as long as sliding member 143 has not been actuated.

In the embodiment illustrated by the drawings such means include an arm 208a„ of lever 208 which comes into a waiting position, when lever 208 has been given its maximum rotation, where it is maintained by a retractable holding finger 213 carried by cradle 200 and urged toward projecting position by a spring 214, said waiting position of arm 208a„ bein^ shown in dotted lines in lig.1.

Holding finger 213 is provided with a lateral projection 213a, disposed in such manner across the tra-jectory of sliding member 143 that the latter retracts said abutment 213 and releases lever 208-208„ when a a said sliding member 143 reaches the end of its active stroke and acts upon said projection 21 a„.

Concerning now the positive transmission mechanism to be interposed between breechblock 34 and the sliding merober 143 of the feed mechanism it comprises a cam 75 located in the gun and journalled about an axis parallel to the longitudinal axis of said gun.

This cam 75 is given an oscillatory movement about its longitudinal axis by a driving finger 84 carried by breechblock 34 and engaged in a helical groove 8¾ provided in said cam 75.

On the other hand, cam 75 is positively connected with sliding member 143 through teeth 89 carried by cam 75, which meshes with a toothed sector 90 provided with external teeth 144 meshing with a pinion 215 rigid with a pinion 216 which in turn meshes with a rack 217 carried by sliding member 143.

In order to make the drawings easier to read, sliding member 143 and its control pinion 216 have been shown as rotated through 90° toward the right in Fig.2 with respect to the positions they occupy in Pig.1.

It will be understood that, owing to such a positive transmission mechanism interposed between breechblock 34 and the sliding member 1 3 of the feed mechanism, not only is said member 143 piloted accurately by said breechblock but the latter may, if necessary, for instance in case of an insufficient recoil of gun 1 with respect to its cradle 200, remedy to a temporary failure of the energy accumulator and then supply sliding member 143 with the energy necessary for ensuring the complete active stroke thereof. The return strokes of sliding member 143 require an amount of energy much smaller than the active strokes and they are controlled by breechblock 34 through the positive transmission mechanism above described.

The complete cycle of operation of the gun will now be described with reference to the diagram of Iig.3 where the times "t" have been plotted in abscissas whereas the strokes of the movable elements are plotted in ordinates along axis L.

Curve Cj in solid lines illustrates the movement of gun 1 with respect to cradle 200 for a complete cycle of operation.

Curve C2 in dash-and-dot lines illustrates the movement of "breechblock 34 during a complete cycle. t-| shows the time of recoil of gun 1. t2 shows the time for which the resilient energy accumulator 202 is placed under tension. t represents the time for which said accumulator transmits energy to the reciprocating member 143 of the feed mechanism if the holding device is not used, t^ represents the time of recoil for breechblock represents the normal recoil of gun 1. represents the recoil stroke of the gun necessary for stressing accumulator 202.

It should be noted that the time t-j for which the accumulator transmits energy to sliding member 143 is only a portion of the recoil time t^ of the breechblock. As a matter of fact, it seems advantageous, in order to obtain a correct feed, to provide periods where the movement of sliding member 1 3 is neutralized, at the beginning and at the end of the recoil stroke of the breechblock, these neutralisation periods being obtained by giving the portions of the groove S3 of oscillating cam 75 that correspond to the beginning n^ and to the end xip of the recoil stroke of said breechblock a rectilinear shape parallel to the generatrices of said oscillating cam.

The operation and the advantages of an automatic gun as above described result sufficiently clearly from the preceding description for making it unnecessary to give further explanations concerning them.

In a general manner, while the above description discloses what is deemed to be a practical and efficient embodiment of the present invention, said invention is not limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the invention as comprehended within the scope of the appended claims.

Claims (1)

1. υ 22933/2 , ■ OLAIMB '"! 1· A gun including a longitudinally reoiprooatijag movable breechblock and an ammunition feed devioe actuated mechanical ■ by energy supplied by an accumulator of/elastio energy (e.g. a spring) periodically supplied with energy by a movable portion of the gun other than the breeohblock thereof bu having a reciprocating movement at the same rate as that of said breechblock, characterised in that the feed device movable parts to be actuated are continuousl coupled with the movable breeohblock o the gun through a positive transmission mechanism capable of having said movable parts piloted by said breechblock, that is to say through a transmission mechanism capable of constantly controlling the instantaneous positions of said movable parts in accordance with the instantaneous positions of the movable breechblock of the gun* 2. A gun according to Claim 1 adapted to recoil as a whole, against the action of a buffer system, with respect to.a stationary support for the feed device of the gun, characterised by the fact that the accumulator Intended to actuate the movable parts of the feed devioe during the active stroke of said movable parts is periodically stressed by the recoil of the whole of the gun with respect to said support. 3· A gun according to Claim 1 further characterized by the fact that the positive transmission mechanism interposed between the feed device movable parts to be actuated and the movable breechblock of the gun is arranged in such manner that movement of said movable parts is inhibited at the beginning and at the end of the recoil stroke of said movable breeohblook. 3498-6^ H. A gun according to cla'im 1 further characterized by the fact that the positive transmission mechanism interposed between the feed device movable parts to be actuated and the movable breechblock comprises a longitudinal cam extending on the inside of the gun parallelly to the axis thereof » said can being on the one hand oscillable about its axis under the action of a driving finger carried by the movable breechblock and engaged in a groove provided in said cam, and, on the other hand, positively coupled with said movable parts to be actuated through transmission elements ensuring the desired law of movement for the movable parts to be actuated. 5. Λ gun according to claims 3 and 1 further characterized by the fact that the groove of the oscillating control cam is provided, near its ends, with rectilinear portions directed along the generatrices of said cam and ensuring the desired neutralization periods s said rectilinear portions being connected together by a portion of helical shape. 6. Λ gun as above described and illustrated by the appended drawings. Dated this 5th day of February, 1965 For the Applicants /1/65-St.