US2366395A - Cartridge feeding mechanism for automatic guns - Google Patents

Description

2 Sheets-Sheet 1 V C. T. HALL Fil ed Nov. 26, 1941 lllllllllllv Jan. 2, 19 45.

C. T. HALL Jan. 2, 1945.

CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC GUNS Filed Nov. 26, 1941 2 Sheets-Sheet 2 3 WMFMM PM Fen/5'02 Aria 1 72 (7y:

Patented Jan. 2, I945 CARTRIDGE FEEDING MECHANISM FOR AUTOMATIC GUNS Charles Thomas Hall, Deptford, London, England, assignor to Molins Machine Company Limited, Deptford, London, England 1 Application November 26, 1941, Serial No. 420,570 In Great Britain January 21, 1941 1 Claim.

This invention is concerned with improvements in or relating to cartridge feeding mechanism for an automatic gun in which cartridges are fed in winding mechanism connected with said spring and adapted for rotation in one direction only and wherein a swinging member adapted to be intermittently engaged and actuated by an actuating element movable with a recoiling part of the gun is arranged intermittently to rotate said mechanism to effect reloading of the spring. Such feeding mechanism will be referred to below as "cartridge feeding mechanism as specified.

In automatic guns fitted on aircraft where the feeding mechanism and barrel are separately attached to the air frame, the relative movement between the gun barrel and the cartridge feeding mechanism frequently varies considerably, and an object of the present invention is to provide a cartridge feeding mechanism which will rotate the winding mechanism an effective constant amount after'each shot is fired, even where the relative movement between barrel and feed mechanismis subject to considerable variation as in the case just mentioned.

According to the invention there is provided acartridge feeding mechanism as specified, wherein a cam is provided on the swinging member and has two portions which are capable of being engaged successively by the actuating element, the first said portion of the-cam being inclined to a radial line drawn from. the axis of the swinging member to the driving side of said actuating-element and located between said axis and the part of the actuating-element which engages the first said portion of the cam, the parts being so arranged that during a predetermined initial movement of the actuating-element the distance between the latter and the axis of the swinging member is reduced, and wherein the length of the first said portion of the cam is such that the actuating-element engages the junction between the two portions of the cam after the actuating-member has moved said predetermined distance relatively to the cartridge feedin mechanism, the second cam face being so arranged that any continued relative movement of the actuating member will cause a reduced swinging'movement of the swinging mem ber.

The winding mechanism may comprise a pair of co-operating bevel gear-wheels, one of which is connected with the spring and is mounted for movement relatively to said "shaft, while the other of said bevel gear-wheel is mounted for rotation and is connected with a ratchet wheel operable by said swinging member.

An embodiment of the invention will be described with reference to the accompanying drawings which show the feeding mechanism for an automatic gun firing 20 m./m. projectiles.

In the drawings:

Figure 1 is an elevation partly in section of feedin mechanism, constructed according to the invention.

Figure 2 is an end elevation of Figure 1 looking in the direction of the arrow A.

Referring to the drawings the feeding mechanism is located above the barrel I of th gun and comprises a substantially cylindrical casing 2 having at one side an opening 3 through which a disintegrating belt comprising clips 4 containing the cartridges 5 can pass, and at the opposite side of the breech a further opening 6 through which the empty clips 4 may fall as indicated in Figure 2. The barrel of the gun is adapted to be slidably mounted on a support, not shown (e. g. the framework of an aircraft) so as to allow for recoil whilst the cylindrical casing 2 is fixedly mounted on the support as described below, thus as the barrel recoils there is relative movement between the cylindrical casing and the gun-barrel in the direction of the axis of the gun-barrel and as indicated by the arrow B Figure 1.

The casing 2 has end plate I and 8attached thereto by bolts 9 and within the casing there is mounted for rotation a shaft In to which is secured a plurality of feeding elements consisting of sprockets II which are adapted to engage the cartridges and to feed them successively in to position above the breech of the gun. The shaft is rotated by a loaded spiral spring l2. the outer end of which is secured to a casing i 3 fixed to one of the feeding elements II. In operation this spring is pre-loaded to a desired tension in readiness for the gun to be fired. The other or inner end of the spiral spring is secured to a sleeve l4 mounted for rotation about said shaft and arranged to be movable relatively to the shaft in an angular direction. As the mechanism operates to feed a cartridge into position above the breech of the gun, the spring is partly unwound or unloaded as each cartridge is fed. .In the example given, the spring is partly unloaded to the extent of A1 of a complete tum. If it is desired that the feeding mechanism shall remain effective for an-indefinite period, it is necessary secured a ratchet wheel IS. The ratchet wheel.

is rotated step by step due to the recoil of the gun-barrel in the manner described below. A spring urged stop pawl 20 is provided to prevent the ratchet wheel, and consequently the'bevel gear wheels, from being rotatedin the reverse T direction.

To effect the rotation of the ratchet wheel, a swinging member or lever 2| is provided and freely mounted on the spindle If! to which the ratchet wheel is secured and the swinging member supports a pawl 22 which is spring urged by a spring 23 towards the ratchetwheel. The swinging member is provided with cam faces 24 and 29 with which a cam roller or actuator element 25 supported on a bracket 26 attached to the gun barrel, co-operates. A spring 21 is pro-' vided to urge the swinging member towards the cam roller. As the gun-barrel recoils, the swin ing member is caused to rotate about the spindle H with the result that the pawl carried by the swinging member rotates the ratchet wheel one tooth. This movement of the ratchet wheel is transferred to. the sleeve through the co-operating bevel gear-wheel and these elements are so selected that the sleeve is angularly rotated by a distance (i. e. V1 revolution per stroke) such as to reload the spring to the same extent that it was unloaded by the previous feeding action. The

casing 2 is anchored to the support by studs 28 one of which is visible in Fi e 1.

As has been previously stated, there is relative movement between the gun-barrel and the cylindrical casing in the direction of the axis of the gun-barrel and although the extent of relative movement might, in theory, be considered substantially constant, nevertheless in practice, especially where the gun is carried by an aircraft, there may be some considerable difference to in the extent of this relative movement. In the particular example being described, the gun barrel is so mounted as to be capable of movingap proximately m./m. in one direction relatively to the cylindrical casing 2, but owing to movement of the parts of the air frame itself, which frequently happens, this relativemovement does not always amount to as much as 20 m./m. It

nism should be so designed as to allow the spring to be rewound to the desired extent on each recoil (even though the amount of relative movement is only about half of the 20 m./m.)',.and yet at the same time to prevent overwinding if the full 20 m./m. relative movement occurs. This possible variation in the extent of movement between the cylindrical casing and the gun-barrel is allowed for by providing the swinging member with the cam face 24 which is inclined to a radial line (e. g. the line :r:-y Figure l) drawn from the-axis about which th': member 2| swings tangential to that side of the roller which is ad'- jacent to the. swinging member, the disposition andinclination .of said cam face being such that as the roller "moves on its operative stroke the member swings through an angle proportional to positions of the roller and casing and then draw another roller position 12 m./m. from the initial position. At this second position the comer I assess:

the rate of linear movement of the roller plus an increment due to the relative movement of said roller along said cam face.

By this arrangement it. will be appreciated that a the cam roller 25 movestowards-the cylindrical casing 2, the inclined cam face 24 willturn as the member 2| swings around the axis of the spindle At the same time the effective radius of the member 2| will become smaller as the contact point between the roller and the member moves up the cam face 24 and thus the swinging member will move for a time through an increasing' angular distance for each unit of relative linear movement between the gun-barrel and the casing The rate of angular movement per unit of linear movement will, however, begin to decrease again as the roller reaches the end of the face 24. I I

In the construction described the inclined cam face 24 is of such a length that when the relative movement lengthwise of the gun barrel from the commencement of the recoil amounts to 12 m./m. the swinging member i moved through an angle about the axis of the spindle l1 sufficient to cause the ratchet wheel to move a distance of one tooth, and the cam roller is at the end of this 12 m./m. movement in engagement with the end of the inclined face, that is the roller contacts with the corner or junction formed by'the meeting of the cam face 24 and another cam face 29 of the member 2|:

The angle of inclination between the cam face and the above mentioned radial line drawn from the axis-of oscillation of the swinging member will depend upon the stroke which it is desired shall be effective to cause the ratchet wheel to move a distance of one tooth. For instance, where it is decided, as in the present example, that a relative movement of 12 m./m.- shall be the distance necessary to turn the ratchet wheel one tooth the angle of inclination of the cam face 24 may be obtained as follows: Set out the initial formed by the junction between the cam faces 24 and 29 should contact the roller and then by transferring the partial shape of the member 2| thus obtained back to the initial position a line may be drawn from the corner tangential to the roller in said first position. This line is at the desired angle of inclination. It will be understood that the cam face need not be a flat face;

' the face could be made suitably curved along its is, therefore, important that the reloading mecha v length. It would of-course still be considered as inclined to the radial line mentioned above. The angle of the face 24 will depend upon a number of varying factors, for example the amount of an ular movement required by the swinging member to effect a stroke of one tooth, the diameter of the cam roller and the size and disposition of the roller and the casing. From this data it will be stantially parallel to the aforesaid radial line from the centre of its axis of rotation. Thus, any continued relative-movement between the gun-barrel and cylindrical casing will cause a proportionately smaller swinging movement of the swinging member than was obtained when the cam roller was acting on-the inclined face 24. Therefore, taking the present example, when the roller and cylindrical casing have moved a relative distance of 12 m./m., the swinging member will have moved through an angle sufficient to have caused the ratchet wheel to have moved through the distance of one tooth, but a further or 12 m./m. movement between the two would not cause the swinging member to move through a corresponding angle. The angle would be much smaller forthe last 10 or 12 m./m. This angle would be considerably less than the distance of one tooth and accordingly it is not possible with this construction to overwind permanently, since the further movement of a part of a tooth would immediately be cancelled out as soon as the gungagement with the cartridge case. Immediately after this the cartridges fall out of the grooves of the sprocket wheels and pass into a trough or chute 3'! and tilt nose downwards as they apbarrel had moved forward again after its recoil stroke.

The spring H, a previously stated, is suitably tensioned prior to the gun being put into action and due to the rewinding apparatus above described, the spring is again fully loaded after each feeding movement. In order initially to load the spring, means to permit manual rotation of the ratchet wheel may be provided on the spindle which supports the ratchet wheel. This means may comprise the shaping of the projecting end of the spindle at 39 in a manner such that a spanner can be applied thereto, or in a more convenient method, the swinging member may be' extended as shown by the chain lines Figure 1 and provided with an aperture into which a bar 3| may be inserted to permit manual oscillation of the swinging member.

In order to prevent initial overwinding of the spring, when a bar is employed, the bar may be split and a suitable spring urged friction clutch provided between the two parts of the bar. The loading of the spring clutch can be such as to equal the desired maximum loading of the spring, so that when the bar has wound the spring sumciently, any further actuation of the bar will cause the spring clutch on it to slip and so prevent overwinding.

While some of the devices shown in the drawings but not previously described, such for example as the devices for feeding and disintegrating the belt, form no part of the present invention, a

brief reference thereto is thought desirable for clarity. It will be observed from the drawings that the end plate 1 has a projecting portion 36 concentric with its centre extending around a part of the circumference. The interior of said projection constitutes a crown cam whereby the cartridges are gradually pushed lengthwise of the casing as they travel round on the feeding elements H. As the clips 4 are constrained by one of the sprockets II from moving lengthwise with the cartridges 5, the latter are gradually slid along the clips until the clips can fall away from the cartridges and down the chute 6. In Figure 1 the cartridge has moved about half of its travel around the casing and the left hand part of the clip 4 is therefore already almost free-from enproach the axis of the barrel whereupon the breech mechanism closes and pushes the cartridge into the breech. These various movements are controlled by sundry fingers and other devices mounted on the hubs of the elements it but omitted from the drawings. A cam 38 is fixed to the end plate 8 and co-operates with the cam 36 to control the cartridges during their axial movement.

L What I claim as my invention and desire to secure by Letters Patent is: In a cartridge feeding mechanism for automatic guns of the type provided with a recoiling gun member and feeding mechanism for supplying cartridges to the gun breech, including spring means adapted to be wound by relative movei ment of the recoiling member and feeding mechanism for actuating the latter, the combination with rotatable winding mechanism for said spring means including a pawl and ratchet device, of cooperating means on said gun member and said winding mechanism for successively advancing said pawl and ratchet device through'a stroke than during an earlier portion of the stroke v of the same length, said cam face being provided with two portions which are engaged successively by the follower, the first said portion of the cam face being-inclined to a radial line drawn from the axis of the swinging member to the driving side of said follower and located between said axis and the part of the follower which engages the first said portion of the face, the parts being so constructed and arranged that during a predetermined initial movement of the follower, the distance between the latter and the axis of the swinging member is reduced, the length of the first said portion of the cam face being such that the follower engages the second portion of the cam face after the follower has moved said predetermined distance relatively to the cartridge feeding mechanism, the second portion of said cam face being so constructed and arranged that any continued relative movement of the follower will cause less swinging movement of the swinging member than is effected by said first portion of said cam face.

CHARLES, THOMAS HALL.

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