US3041939A - Multi-barrel gun with a plurality of firing stations and an ammunition drum - Google Patents

Description

y 1962 Di DARDICK 3,041,939 MULTI-BARREL GUN WITH A PLURALITY 0F FIRING STATIONS AND AN AMMUNITION DRUM Filed Oct. 6. 1959 2 Sheets-Sheet.1

H3 5 6 2FIG.I

IN VEN TOR.

DAVID DA RDICK ATTORNEYS y 3, 1962 D. DARDICK 3,041,939

MULTI-BARREL GUN WITH A PLURALITY OF FIRING STATIONS AND AN AMMUNITION DRUM Filed Oct. 6, 1959 2 Sheets-Sheet 2 IN VEN TOR.

DAVID DARDICK wn hgzwa ATTORNEYS United States Patent fifice 3,041,939 Patented July 3, 1962 3041939 MULTI-BARREL GUbi WITH A PLURALITY OF FIRING STATIONS AND AN AMMUNITION -DRUM David Dardick, New York, N.Y., assignor to, Dardick Corporation, a corporation of Delaware Filed Oct. 6, 1959, Ser. No. 844,773 15 Claims. (Cl. 89-126) This invention relates to multi-barrel guns and relates more particularly to a multi-barrel gun of utility especially in a weapons system for application to the defense of strategic aircraft, such as heavy, long-range bombers,

against air-to-air or ground to air missiles.

It is among the objects of this invention to provide a multi-barrel gun for firing small calibre, high velocity projectiles at ultra-high rates so as to produce a relatively large, dense projectile pattern through which an attacking missile must travel, thereby making it virtually impossible for the attacking missile to penetrate this projectile pattern without suifering a hit on the vulnerable guidance system or warhead.

Another object of this invention is to provide a multibarrel gun having an energy output, per unit of weight of the gun, several times higher than that achieved with any previous or contemplated gun system of this class.

Other and further objects of this invention will appear from the following. description, the accompanying drawings and the appended claims.

Speaking generally, the gun of this invention is based on the open chamber principle disclosed in my issued US. Patent No. 2,865,126 for Open Chamber Gun, whereby no reciprocating action is employed of either the ammunition or the major gun parts in obtaining a completely obturated firing chamber. An open-chamber drum mounted for rotation on its cylinder axis carries a circular row of gun barrels, one for each open chamber, which rotate with the drum. This drum is encaged by a stationary breech frame which provides, preferably, four firing stations. Preferably also there are ten barrels carried by the drum. With ten barrels attached to the drum and four firing stations, forty rounds may be fired at each revolution of the drum and barrel assembly. Thus, with the assembly rotating at a high speed, for example, 3000, revolutions per minute or fifty per second, the firing rate would be 2000 rounds per second.

Four separate belts of ammunition are fed to the gun, one at each firing station. The ammunition, in belt form, remains at rest, adjacent the gun until such time as feeding is to commence. The belts are equipped with collapsed linkage between successive rounds, so that only one round per belt at a time is accelerated, when feeding commences, thus precluding high belt loads. A suitable camming device which may be operated by a solenoid or a pneumatic actuator functions to push the first round of each belt into position in a drum recess when firing is to commence. The round is fired when it is covered by the stationary breech structure and remains covered during the period of high pressure, while the projectile is traveling'through the bore. As soon as the case is uncovered by further movement of the drum, an ejector which may be cam-actuated, forces the case out of the drum recess, aided by centrifugal force.

A light multi-stage high speed turbine unit is built into the gun as an integral part thereof, this turbine being powered by gas tapped from the barrels into a turbine plenum. chamber. Suitable reduction gearing between the turbine and the drum and barrel assembly reduces the turbine speed, for example, 20,000 revolutions per minute, to the desired. drum speed, for example, 3000 r.p.m. At this drum speed and with, forty rounds being fired at each revolution, the firing rate of the gun would be 120,000 rounds per minute.

Advantageously, an electric motor may be provided as an integral part of the gun to bring the drum and barrel assembly up to speed before firing commences, in which case, duringfiring, the turbine unit sustains the velocity of' rotation against friction forces. The motor unit in such case may drive the drum and barrel assembly through the same reduction gearing as the turbine unit. 7

When firing ceases, as by the deenergization of a firing circuit, the same feeding actuator or camming device blocks the belt adjacent to each firing station. This shears the link connecting pin, breaking the belt, and leaves the first round of the remainder of the belt in position to be fed during the next firing cycle. There, the drum and barrel assembly is continued in rotation by the electric motor unit over an idling cycle, there will be no accelerating period when firing recommences.

The gun may be programmed by the particular weapons system with which it is designed to be employed, to fire in bursts of one second each, or 2000 rounds per burst. This is believed to be sufficient to obtain high hit probabilities against vulnerable areas of even small missiles. Due to the short firing time of each burst, thermal inertia is relied upon to preclude the heating of the entire barrel cross section to dangerously high temperatures.

The projectiles in the ammunition rounds are preferably pre-engraved to permit proper engagement with rifling even when the barrel lands are in a semi-plastic state. The ammunition employed comprises a thin-walled case of generally equilateral triangular configuration, in cross-section, thickened at the corners and supporting the projectile in its interior. At least one wall of the case is of a radius of curvature the same as that of the open-chamber drum of the gun so as to constitute a continuation or extension of the arcuate drum surface when in position in the open chamber. The case may be of a suitable light weight metal, such as aluminum, and be combined with a bullet-supporting and gas sealing sleeve such as in the ammunition disclosed in the US. Patent No. 2,865,126 aforesaid. Preferably, however, the case is formed of a high density olefin polymer resin such as the Fortifiex A brand of linear polyethylene produced by Celanese Corporation of America in accordance with its so-called A-70 formulation. Fortiflex is a registered trademark of Celanese Corporation. In the use of such resin for the case where the calibre of the ammunition is low as contemplated for the multibarrel gun of this invention, the bullet-supporting obturating sleeve may be dispensed with since the density and elasticity of the resin is sufiicient for the material to flow and seal the joint between the muzzle end of the case and the breech end of the gun barrel, on firing. Moreover, the relatively low cost and light weight of the polyethylene case is highly advantageous as respects the logistics problem with the gun of this invention whose firing rate is extremely high.

In the accompanying drawings which form part of the instant specification and in which like numbers refer to like parts throughout the several views:

FIG. 1 is a part-sectional view in side elevation of a multi-barrel gun in accordance with this invention;

FIG. 2 is a fragmentary sectional view to an enlarged scale of a detail of FIG. 1;

FIG. 3 is a view in section taken along the line 33 of FIG. 1; 0

FIG. 4 is a view in section taken along the line 4--4 of FIG. 1;

FIG. 5 is a view in section taken along the line 55 of FIG. 1;

FIG. 6 is an isometric view of a portion of an ammunition belt such as is used in the gun of FIG. 1, the view showing two rounds of the ammunition of generally equilateral triangular in cross section and the connecting linkage of the rounds; and

FIG. 7 is a diagrammatic view depicting the inner and outer rotor system of the gas turbine unit of the gun of FIG. 1.

Referring now more particularly to the accompanying drawings, there is depicted a multiple barrel open-chamber gun of a weapons system in accordance with this invention. As embodied, the gun comprises a rigid breech frame 1 which encages a hollow cylindrical ammunition drum 2 having, circumferentially, a circular row of equally angularly spaced radially arranged identical ammunition recesses 3 which serve as open-chambers and are adapted to receive successively each a round of the generally triangular ammunition 4 such as is depicted in FIG. 6. As here preferably embodied, the ammunition drum 2 is provided with ten of the open-chamber 3 spaced at equal angular intervals of thirty-six degrees (36) from each other.

Beginning at the plane of the forward end of the openchambers 3 (that is, at the right hand end of the chambers as viewed in FIG. 1) the drum is enlarged in diameter to provide a cylindrical barrel-carrying portion 5 which, as shown, is of uniform diameter from end to end. This barrel-carrying portion is apertured longitudinally to provide a number of barrel-receiving apertures 6 arranged in a circular row concentric with the drum cylinder axis, and individually aligned longitudinally with the respective open-chambers, for receiving the individual gun-barrels 7. Thus, the barrels 7 are individually suitably aligned longitudinally with the respective open-chambers 3 to permit of the passage of a bullet 8 from any one of the openchambers into and through the rifled bore 9 of the associated barrel. Each barrel is also removably secured at its breech end to the barrel-carrying portion 5 so that replacement of a barrel may be effected at will. As here preferably embodied the breech end of each barrel is provided with a circumferentially threaded portion '10 in threaded engagement with a complementary threaded portion of the associated barrel-receiving aperture 6. It will be understood that this threaded portion need not extend over the full length of the barrel-carrying portion 5, but only for the distance which is determined to be necessary for the secure fixing of the barrel therein.

The gun as a whole may be mounted pivotally to a diagrammatically depicted turret portion 11 for movement in elevation, as by means of a two-part mounting member '11 which, as shown, may be releasably clamped at its upper end to the rigid breech frame 1, and at its lower end to the turret portion 11, as by means of the horizontal pivot pin assembly '11", for pivotal elevational movement on a horizontal axis.

Advantageously, the turret 11 may be journalled to a suitable carriage (not shown) for rotation in azimuth relative to the carriage on a vertical axis. Suitable mechanical or hydraulic servo system means (not shown) for elevating and traversing the gun relative to the carriage, may be provided. The carriage may be, for example, a strategic aircraft such as a heavy, long range bomber carrying, as elements of the weapons system, a suitable, short-range, radar and fire control system (not shown) combined with an IFF (Identification Friend or Foe) device (not shown). The antenna of the radar system, for example a 6" or 8 disc, would sweep through a predetermined zone and would lock on against any object within 5000-8000 yards which did not respond to the proper IFF code signal. A suitable computer system (not shown) responsive to the radar signals and acting through the suitable servo system above-mentioned, would serve to lay the gun in elevation and azimuth, respectively, and would actuate a firing circuit of the gun at a predetermined range such, for example, as 1000 or 2000 yards.

The rigid breech structure or frame 1, as here preferably embodied, is comprised of a pair of diametrically opposed, top and bottom cantilever breech rails 12, a pair of diametrically opposed cantilever side breech rails 13, and a circular back breech rail 15. The breech rails 12 and 13 parallel the cylinder axis of the drum 2 and are preferably formed integraly with the back breech rail 15 so as to provide a strong and rigid unitary cage-like structure of which the back breech rail is disposed at right angles to the cylinder axis of the drum 2, and the breech rails 12 and 13 extend forwardly from the back breech rail in cantilever fashion and are arranged in a circular row concentric with the cylinder axis of the drum.

The back breech rail 15 is preferably of circular configuration and the breech rails 12 and 13 are disposed around its circumference in an arrangement in which the pair of top and bottom rails 12 is angularly offset from the pair of side rails 13 by ninety degree (90 The back breech rail 15 is suitably axially recessed to provide a cylindrical well 15' co-equal in diameter to and concentrlc with the open-chamber portion of the drum 2. The breech rails 12 and 13 are each of a configuration to provide, as to each, an arcuate breech surface '14 which is concentric with the cylinder axis of the drum 2. The arcuate breech surfaces 14 each constitute an extension of the cylinder surface of the well 15' in the back breech rail. Each has a radius of curvature which is substantially the same as, but not less than, the radius of curvature of the drum 2 over the open-chamber portion thereof. By reason of the substantially co-equal radius of curvature of the arcuate breech surfaces 14 and the open-chamber portion of the drum 2, these surfaces will be in closely spaced substantially wiping engagement with the drums as it is rotated in the breech frame. Thus, as one or another of the open-chambers 3 is brought into register with one or another of the cantilever breech rails, the arcuate surface '14 of the breech rail spans the open-chamber from side-to-side and end-to-end, and a closed ammunition chamber of substantially equilateral triangular shape in cross-section is formed. The side walls 3 of the closed chamber are each preferably arcuate and of co-equal radius of curvature, but it will be understood that the side walls of the open-chamber 3 as such need not be of the same radius of curvature as the arcuate breech surface 14. These side walls converge radially inwardly from the mouth of the chamber, the widest part of the chamber, to the apex or base of the chamber. Instead of being curved they may be planar, or they may be of a larger radius of curvature than the arcuate breech surface 14. In the latter cases, it will be apparent that the ammunition of corresponding shape for use therewith can occupy only one position in the chamber, that is, with the arcuate surface whose radius of curvature is the same as that of the open-chamber portion of the drum 2, at the mouth of the open-chamber. By this formation of the openchamber, each round of ammunition will be pre-indexed in the chamber so that with live ammunition a rotating band on the bullet may be properly indexed with reference to the rifling in the bore 9 of the gun-barrel. Preferably, the breech rails 12 and 13 are of generally I-beam section over the central portion of their length, as indicated at 12 and 13", FIG. 3, so as to minimize deflection from bending moments created therein from firing loads imposed on the arcuate breech surfaces 14. Advantageously, they extend at their free ends beyond the openchamber portion of the drum and overlie the barrelcarrying portion 5 of the drum for a short distance and in suitably closely-spaced conforming relation to the cylinder surface thereof.

The arcuate chamber-forming breech surface 14 of each of the breech rails '12 and 13 is dimensioned circum ferentially of the drum 2 so as to overlie the drum surface over an are substantially longer than the arc subtended by the mouth of one or another of the open-chambers 3. As will be pointed out more fully hereinafter, this rela tively large span of arcuate surface serves also as a keeper for holding flexible link means coupling successive rounds of ammunition, seated in a pair of relatively shallow link grooves 2' formed in the drum 2 and extending circumferentially around the drum.

The back breech rail is centrally suitably apertured to permit the insertion into the hollow interior of the drum, of a generally cylindrical hollow motor casing 16 which is concentric with the drum 2 and contains an electric motor (not shown) for initiating rotation of the drum 2 with its barrels 3 in the stationary breech frame 1. To this end, the casing 16 is enlarged in diameter intermediate its ends to provide an annular mounting and bearing-retaining flange 19 dimensioned to fit slidably and snugly the central aperture in the back breech rail 15.

The forward end of the casing 16, that is, the right hand end as viewed in FIG. 1, terminates in a removable end plate, preferably circular, dimensioned to provide a bearing-retaining flange 20 which is preferably co-equal in diameter with the intermediate bearing flange 19. The surface 21 of casing 16 between these two flanges serves as a mounting for suitable anti-friction bearing means by which the drum 2 is mounted on the stationary motor casing for rotation relative to the stationary breech frame 1. As here preferably embodied, the bearing means comprises a pair of annular ball-bearing assemblies 22 suitably spaced from each other and secured against axial displacement on the bearing surface 21, by concentric spacer rings 23 and the bearing-retaining flanges 19 and 2ft. The drum 2 is carried on and by these bearing assemblies, forrotation on its cylinder axis.

Means are provided on the motor casing 16 for securing the casing against axial displacement inwardly of the breech frame 1, that is, to the right as viewed in FIG. 1. As here preferably embodied, the casing 16 is provided circumferentially with a threaded portion 24 preferably of slightly larger diameter than the bearing flange 19. A nut 25 threadedly engages the threaded portion 24 and bears against a washer26 which, in turn, bears against the back breech rail 15 to fix the casing against movement axially inwardly of the breech frame, that is, to the right as viewed in FIG. 1. Axial movement in the opposite direction from the position shown in FIG. 1 is prevented by the drum 2, as will more fully appear hereinafter.

The motor casing 16 which extends rearwardly from the breech frame, has provision in the form of electrical leads 27 for supplying electric power to the motor (not shown) contained therewithin. The armature shaft of the motor is aligned co-axially with the cylinder axis of the drum 2 and extends through the bearing-retaining end plate 20 for a suitable distance so as to provide a cantilever turbine shaft 28 upon which a set of turbine rotors 29 is mounted and secured fixedly for rotation therewith.

The turbine shaft 28 is circumferentially threaded as at 30 over a portion of its length between an annular retaining flange 31 integral therewith and an un-threaded lesser-diameter end portion 32 of the shaft, to receive threadedly the set of turbine rotors 29. An annular double-flanged retaining and bearing collar 33, concentric with and carried by the shaft end portion 32, abuts the outermost rotor to secure the individual rotors against relative rotation and also provides a mounting for an annular anti-friction bearing assembly 34, for a purpose to be more fully described hereinafter. A retaining collar 35 mounted to the shaft end portion 32 is nested and seated in the bore of the collar 33 and pinned to the shaft by a diametral locking pin 36 passing through the shaft. It will be apparent at this point that rotation of the shaft 28 by the motor (not shown) in the casing 16 will result in the set of turbine blades 29 rotating with the shaft.

Means are also provided in conjunction with the turbine shaft 28, for rotating the drum 2 by means of the motor. As here preferably embodied such means comprise a motor pinion gear 37 fixed to the shaft 28 for rotation therewith. A set of idler gears 38 carried by the casing end plate 20, respectively couple the motor gear 37 to an internal ring gear 39 carried by the barrelcarrying portion 5 of drum 2. The idler gears 38 are suitably journalled for rotation on stationary stub axles 40 arranged in a circular row, each axle being in threaded engagement at one end with the end plate 20 and provided with a flanged gear-retaining head at the other.

The internal ring gear 39 is concentric with the drum 2, the drum being hollow from end-to-end and of an internal configuration from its inner end adjacent the back breech rail 15 over a portion of its length, to pro.-

vide over this portion a central cylindrical bore in which the motor casing 16 is telescopically received. The cy. lindrical surface 41 of this central bore is dimensioned at the inner end of the bore to engage snugly, but axially slidably, the outer-circumferential peripheries of the antifriction bearing assemblies 22 and the outer periphery of the outer spacing ring 23. The internal ring gear 39 is suitably located at the outer end of the cylindrical bore in suitable engagement with the idler gears 38. Thus, the drum 2 by reason of the bearing assemblies 22 may be rotated relative to the breech frame 1, by means of the motor driven gear train comprised of the gears 37, 38 and 39.

With further reference to the drum 2, its internal configuration over the remaining portion of its length is such as to provide for the reception axially of a set of annular turbine rotors 42 (hereinafter called outer rotors) which are intercall-ated with the annular turbine rotors 29 (hereinafter called inner rotors). The inner circumferential surface of the enlarged barrel-carrying portion 5 of the drum 2 is of a configuration to provide internally of the drum means forming an annular turbine plenum chamber 43 into which gas is tapped from the barrels 7 through individual bleed passages 44 connecting the respective barrels With the plenum chamber. The annular discharge port 45 of the chamber is disposed in close proximity to the innermost of the turbine rotors 29 so as to. feed a stream of the relatively high pressure firing gases into the turbine rotors as is diagrammatically indicated in FIG. 7.

An annular flange 46 extends radially inwardly from the interior of the drum 2 between the plenum chamber 43 and the innermost of the outer turbine rotors 42 and provides an annular bearing surface against which this rotor is seated. Each of the rotors 42 has its outer circumferential periphery threaded and in threaded engagement with the inner circumferential periphery of the drum 2. The outermost of the rotors 42, that is, the right hand rotor as viewed in FIG. 1, is provided, preferably, with a tapered threaded surface in threaded engagement with a complementary tapered inner surface of the drum 2 so as to lock the rotors 42 securely to the drum 2 during operation. The outermost of the rotors 42 has its inner circumferential periphery of a diameter and width to receive slidably and snugly the anti-friction bearing assembly 34 and is provided with a radially inwardly projecting annular flange 47 for engaging the assembly 34 and holding it firmly in position on the flanged collar 33. Advantageously, the flange 47 may be equipped with a hollow spinner 48 of an external configuration to effect an axial prolongation of the annular Ventun' throat of the outermost of the turbine rotors 42, as well as to safeguard the internal turbine and reduction gearing elements.

It will be apparent from the foregoing that relative axial movement between the drum 2 and the motor casing 16 is prevented by the interlocking arrangement of the turbine rotors. Axial movement of the drum 2 relative to the fixed breech frame 1 is prevented by the motor casing lock nut 25 and by the seating of the drum 2 in the breech frame.

The chambers 3 are arranged in diametrically opposed pairs, as mentioned above. Thus, if at a given instant in the rotation of the drum 2 the diametral plane of one pair of chambers is vertically disposed, one chamber of this pair will be closed by the upper rail 12 and the other by the lower rails. Thus, the rails 12 fix a firing station for the drum at which one pair of chambers is in battery or firing position, as depicted in FIGURE 3. At this station simultaneous firing of the two barrels aligned with these two closed chambers is possible. Firing is effected while the drum and barrels are rotating at high speed and in the interval during which this particular pair of chambers is completely closed by the arcuate breech surfaces 14 of the upper and lower breech rails 12. Just as the pair of breech rails 12 fix one firing station for the drum, so do the breech rails 13 fix another, the two firing stations being at an angle of 90 to each other. However, because of the preferred 36 angle between successive chambers, only one pair of chambers can be at a firing station at a time, as is evident from FIG. 3. If a pair of chambers is at one firing station as in FIG. 3, another pair of chambers can be brought to the other firing station only by rotating the drum through an angle of 18". It follows that firing occurs alternately at the two firing stations with each 18 of rotation of the drum, and while the drum is rotating at high speed. Unloading and reloading of a fired pair of chambers is effected automatically in the first 90 quadrant between firing stations and during rotation. Unloading is completed in the first 36 of movement and reloading completed in the next 36. The pair of reloaded chambers ready for firing is now approaching the second firing station but is out of register with it by 18. At this moment, a second pair of loaded chambers is at the first firing station and firing to start its cycle in this quadrant. Continued movement of the drum over the remaining 18 of the first quadrant brings the first pair of chambers to the second firing station, firing is effected, and the same cycle is repeated for the first pair in the second, third and fourth quadrants in succession. Thus, in one rotation of the drum each cham her is fired four times so that with the ten barrel gun depicted, there will be 40 firings per revolution of the drum.

Means are provided for firing each chamber at each of the four firing stations during each revolution of the drum. The firing may be effected mechanically as, for example, by employing a rim-fire cartridge and causing the rim to wipe across a suitable firing member capable of imparting a sufficient peak pressure to the primer unit of the cartridge at a predetermined position in the rotational path to detonate it. The firing means, as here preferably embodied, comprises a number of metal plates 50 of suitable resistance heating material, one at each of the four firing stations, disposed in the bottom of the well and arranged in a circular row concentric with the cylinder axis of the drum 2 and flush with the bottom wall 51 of the well. The plates are identical so that a description of one will apply equally to the others. Each plate is bedded in a receptacle 52 of suitable heat resistant and electrically insulating material, through which an electric firing lead 53 of one polarity (plus as shown) passes into electrical connection with the firing plate. A separate electric firing lead 54 of opposite polarity (minus as shown) is electrically connected to the metal breech structure 1. By passing an electric current of suitable amperage through the circuit formed by the lead 53, plate 50, breech frame 1 and lead 54, the plate can be heated to and maintained at a temperature at which heat generated can be transmitted to the conventional electric primer 55 of the cartridge 4, sufficiently fast to heat the primer to a detonating temperature in the time it takes the cartridge to traverse the length of the plae 50. To this end, the end of the drum 2 opposite the plate 50 is provided with heat-transmitting metal firing pins 56, one for each of the chambers 3, of suitably heat-conductive material. The firing pins 56 are preferably cylindrical, are

identical, and are arranged in a circular row concentric with the drum at a radial distance from the rotational axis thereof equal to that of the plates 50. Each is of a length to abut at one end against the firing plates 50 as the drum rotates and at the other end against the primer unit 55 of the cartridge 4 in the associated chamber. Cylindrical heat-insulating jackets 57, one for each rod, of suitable heat-insulating material, closely surround each rod from end-to-end and minimize the flow of heat from the rod to the metal of the drum 2. It will be apparent that as a given chamber approaches a firing station, its firing pin 56 will wipe along the surface of the firing plate 50 at that station. The plates 50 are each preferably arcuate in the plane of the wall surface 51 and dimensioned along the arc to provide the length of heating surface required to assure that the cartridge will be fired just as it reaches the firing station.

Means are provided for automatically ejecting empty cartridge cases from the chambers 3 on their leaving the firing stations. The ejecting means as here preferably embodied comprises a number of cam-actuated ejecting levers 58, one for each chamber, which are pivotally mounted to the drum 3 in channels 59, one channel to each chamber. The levers 58 are identical as are the channels 59 so that a description of one unit will sufiice for all.

Each ejecting lever channel 59 extends longitudinally of and beneath the open-chamber 3 from the breech end of the drum 2 and parallel to its rotational axis, to a point substantially midway of the ends of the chamber. At this latter point it terminates as a relatively narrow opening or slot 69 in the apex or base of the chamber.

The slot 60 extends for a short distance along this base. At its other end it terminates in an opening 61 in the breech end of the drum. The ejecting lever 58 is disposed lengthwise of the channel 59 and is pivoted intermediate its ends to the drum by means of a cylindrical trunnion 62 extending across the channel and journalled at its ends in the channel sidewalls. A pair of trunnion keepers 63 are removably fixed in the channel at diamet rically opposite sides of the trunnion and are apertured suitably for the passage of the lever arms and to permit the lever to rock on the cylinder axis of the trunnion. The lever 58 is generally L-shaped to provide at its forward end (the right hand end as viewed in FIG. 2) a hammer portion 64 disposed in the opening 60 so as to be in contact with the cartridge 4 at its apex. The portion of the lever from the trunnion 62 to the other end of the lever is disposed at a slight angle to the longitudinal axis of the channel 59 so as to be inclined radially outwardly relative to the drum and extends through the opening 61 for a short distance beyond the plane of the bottom wall 51 of drum well 15'. To accommodate this extending end, the back breech rail 15 is further recessed inwardly from the plane of the wall 51 for a distance sufiicient to clear this end. The annular wall 65 thus provided parallels the annular bottom wall 51 and 1s connected thereto by an annular wall 66 concentric with the drum 2. The wall 66 serves as a camming surface for actuating the ejecting levers 58 and to this end is provided with suitably shaped camming ramps 67 which extend radially inwardly from the wall 66 for depressing the extending ends of the ejecting levers 58, at suitable intervals during rotation of the drum. The ramps 67 are spaced at equal angular distances from each other, one being located between each pair of firing stations. Each ramp has its greatest elevation located at an angle which, measured from a firing station in the direction of rotation of the drum, is 36. The shape of the ramp over its leading and trailing surfaces is selected to initiate depression of the ejecting lever for a given chamber just as soon as the chamber is clear of an overlying arcuate breech surface 14 and to complete the depression in the shortest possible time consistent with the avoidance of undue stresses in the lever. It will be understood that 9 the primary function of the ejecting levers is to free the empty cartridge case from the chamber and initiate ejection. The case once freed is aided in ejection by centrifugal force operative at the high rotational speed of the drum. A

Means are provided for feeding up to four belts of ammunition to the drum at a time as it rotates. The individual rounds of ammunition 4 depicted in FIGS, 2 and 6 comprise a relatively thin-walled case of equilateral triangular shape in cross-section and thickened at the corners. As shown, the case walls 65' are arcuate and have each the same radius of curvature as the chambered surface of the drum 2. A projectile 8 is carried in the interior of the case in a cylindrical sleeve 66' which terminates at its forward end in an obturating flange 67' conforming in shape to the internal cross-sectional configuration of the case so as to' be in slidable sealing engagement therewith. The projectile 8 as shown is provided with a rotating band 68 pre-indexed relative to the case so that the band lands 69 will engage accurately with the grooves 70 of the rifling in the bore of the barrel 7 as the projectile enters the barrel.

A propellant 71 in the case is adapted to be ignited by the primer 55 when the cartridge 4 is at a firing station, the primer 55 as shown being carried by an end closure 72 press-fitted in the case and conforming in transverse cross-section to the interior triangular configuration of the case. Although the case shown is fabricated of a light metal such, for example, as aluminum, it, including the primer support and end closure may be a one-piece unit of high density linear polyethylene. At the small calibres of, for example, .25 calibre intended for use in the multi-barrel gun of this invention, the bullet-supporting and gas-sealing sleeve 66' may be dispensed with entirely and the interior cross-sectional configuration of the case be circular. In such case, the projectile 8 would be positioned in'the case in the same relative position but be in press-fit engagement with the interior surface of the case throughout the entire circumference thereof. The elasticity of the high density linear polyethylene enables the case as such to expand longitudinally under the firing pressures into gas-sealing engagement with the breech end of the gun barrel 7. At the same time the flow of the material of the case circumferentially results in the circular interior of the case tending to achieve a triangular configuration in cross-section, conforming to the triangular shape of the walls of the closed chamber, thereby ensuring that the case Walls will be pressed into firm contact with the closed chamber walls over the entire opposed surface areas of case and chamber.

The rounds of ammunition 4 are linked together at corresponding ends into a belt by means of links 67" connected together pivotally in end-to-end relation and to the case walls so that the rounds may be collapsed together as shown in FIG. 6, for economy of space in packing of the belt in ammunition boxes. As fed to the drum 2, the leading round only is accelerated first by pull on the belt and the succeeding rounds accelerated successively as the collapsed linkage between successive rounds straightens out.

The belt feeding means for each firing station is the same so that a description of one will suifice for all. As here'preferably embodied, the belt feeding means for a givenstation comprises a rigid supply chute 73, FIG. 3 leading to the circumferential surface of the drum 2 at one side of the firing station and a discharge chute 74 leading from that surface at the opposite side. The supply chute may be connected at its outer end to a magazine '(not shown) in which the ammunition belt is stored in accordion fashion with the links between rounds in a fully collapsed state substantially as depicted in FIG. 6. The discharge chute may be connected to an empty magazine (not shown).

The supply chute 73 as shown comprises top and bottom wall members 75 and 76, respectively, spaced apart a distance to accommodate the ammunition rounds 4 slidably, freely without possibility of jamming. The wall members are dimensioned fromside to-sideso as to fit closely "at the inner end of the chute structure within the space between the barrel-carrying portion 5 'of the drum and the back'breechwall 15. They are connected together at their corresponding side edges by side wall members (not shown) to provide an open-ended closed structure preferably rectangular in cross-section. The lower wall member 76 extends substantially radially of the drum 2 and terminates at the arcuate surface thereof. The upper wall member parallels the lower wall member except over its inner end portion 77 where it diverges outwardly therefrom along a circular arc of a radius corresponding substantially to that ofthe drum. This arcuate end portion terminates close to the drum and substantially tangential thereto along a line essentially coincident with the near edge of the arcuate breech surface 14.

The discharge chute 74 similarly comprises upper and lower wall members 78 and 79, respectively, and side wall members (not shown) to provide an open-ended closed structure substantially rectangular in cross-section. The upper Wall member 78 is of substantially the same arcuate shape as the correspondingfwall member 75 of the supply chute, over its inner portion 80. The lower wall member 79 is also arcuate and substantially parallels the upper wall member, instead of extending radially of the drum as in the case of the corresponding wall of the supply chute.

From the foregoing it will be apparent that by feeding the ammunition belt in collapsed link form into the outer end of the supply chute 73, the leading round of ammunition can be placed in a position close to the rapidlyrotatingsurface ofthe An electrically operated solenoid 81 is disposed in suitable relation to the drum surface to enable its reciprocable armature 82 to be projected into contact with the leading round of ammunition and to push it into the mouth of the first empty chamber 3 that comes by. The drum'carries the round forwardly against the curved inner portion 77 of the upper wall member 75 by which it is smoothly seated fully in the chamber. As the round continues to advance (counter-clockwise in FIG. 3) the links 67" between it and the next round are extended until the next round is drawn forward by the continued movement. The round moves forward beneath the arcuate breech surface 14, is fired, and as it moves out from beneath the surface is moved out of its seat in the chamber by the action of the ejecting lever 58 so as to be guided into the mouth of the discharge chute 74. Continuing rotation of the drum ensures continuous uniform forward movement of the belt through the gun, with each cartridge being fired as it passes through the firing station. The flow'ot the belt can be interrupted at any instant by energizing the solenoid 81 so as to interpose the armature pusher 82 in the belt path, thu s breaking the linkage between roundsQ According to one design of the gun as herein embodied, the barrels 7 are of 0.25 calibre, firing a grain projectile with a muzzle velocity of 3000 ft./sec. The firing rate is 2000 rounds per' second, when feeding four separate belts of ammunition to the gun, one at each firing station. The electric motor 16, of approximately /2 HR, rotates the drum and barrel assembly through the reduction gearing at a constant rate of 3000 revolutions per minute, or 50 per second. 7 Since there are ten of the barrels 7 attached to the drum 2, one opposite each chamber 3, and there are four firing stations 12, 12 and 13, 13, 40 rounds are fired at each revolution, 50 40=2000 rounds per second. The light multi-stage turbine comprising the inner rotors 29, and outer rotors 42 has a speed of 20,000 revolutions per minute, whose speed is reduced to'30'00 r.p.m, by means of the reduction gearing, "and maintains the velocity of rotation M =weight of projectile=l grains V=muzzle velocity=3000 ft./sec. R=rate of fire=2000 rounds/sec. W=weight of weapon=60 lbs.

MV R E 29 W is as follows:

100 3000 2000 E- -66,500 ft. lbs./sec./lb. of gun It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention.

What is claimed is:

1. A multi-barrel gun comprising a stationary breech structure having breech rails arranged in a circular row and having arcuate breech surfaces, one for each rail, concentric and co-equal in radius of curvature, said breech rails providing a circular row of equally arcuately spaced individual firing stations; an ammunition drumgun barrel assembly comprising a cylindrical ammunition drum co-equal in radius of curvature with said arcuate surfaces, mounted for rotation on its cylinder axis concentrically with said arcuate surfaces, said drum having a circular row of equally angularly spaced open ammunition chambers arranged around its circumference for the reception successively individually of a round of ammunition between each firing station and the next succeeding firing station inthe direction of rotation of said assembly, and for closure successively individually by said arcuate breech surfaces individually at each of said firing stations, and gun barrels, one for each chamber, carried by said drum for rotation therewith, said barrels being arranged in a circular row concentric with said cylinder axis; motor means operatively coupled to said assembly for rotating said assembly; and reaction means powered by firing gases from said barrels for supplying a supplementary rotational force to said assembbly during firing.

2. A multi-barrel gun in accordance with claim 1 in which said firing stations are ninety degrees apart.

3. .A multi-barrel gun in accordance with claim 1 in which said firing stations are ninety degrees apart and in which said open chambers are thirty-six degrees apart.

4. A multi-barrel gun in accordance with claim 1 for use with ammunition linked together in belt form in which said drum is circumferentially grooved for the passage between said arcuate breech surfaces and said drum of the belt linkage.

5. A multi-barrel gun in accordance with claim 1 including ejecting levers, one for each chamber, mounted pivotally to said drum between the rotational axis of said drum and the bottom of the individual chambers, the chambers being provided individually with an opening in the bottom for the movement of the associated lever into and out of the chamber; and said breech structure having camming ramps, one between each pair of firing stations, for actuating said ejecting levers.

6. A multi-barrel gun in accordance with claim 1, including means at each firing station for firing a round of ammunition in a chamber at the firing station.

7. A multi-barrel gun in accordance with claim 1 including a plurality of ammunition belt feeding means, one at each firing station and operatively associated with the portion of said drum positioned thereat, each belt feeding means comprising a supply chute for feeding ammunition in belt form to the drum at one side of the firing station and a discharge chute for conducting the fired ammunition from the drum at the opposite side of the station, said supply chute having a lower wall member extending generally radially outwardly of said drum and an upper wall member which includes an arcuate end portion diverging outwardly from said lower Wall member along a circular arc of a radius corresponding substantially to that of said drum, said arcuate end portion terminating close to said drum and substantially tangential thereto along a line essentially coincident with the near edge of the arcuate breech surface of the breech rail at the firing station, and said discharge chute comprising upper and lower curved wall members leading from said drum adjacent the station.

8. A multi-barrel gun in accordance with claim 1 including a plurality of ammunition belt feeding means, one at each firing station and operatively associated with the portion of said drum positioned thereat, each belt feeding means comprising a supply chute for feeding ammunition linked together in belt form, to the drum at one side of the firing station and a discharge chute for conducting the belt with fired ammunition from the drum at the opposite side of the firing station, and a plurality of extensible means associated with said supply chutes, one to each chute, movable at will into the path of movement of the belt in said supply chute for engaging the first round of ammunition of the belt in the supply chute to urge said round into an empty recess of the drum during rotation thereof and for blocking further movement of said belt in said chute, at will.

9. A multi-barrel gun in accordance with claim 8 in which each said extensible means is an electrically actuated solenoid.

10. A multi-barrel gun comprising a stationary breech structure having parallel top, bottom and side breech rails arranged in a circular row and having arcuate breech surfaces, one for each rail, concentric and co-equal in radius of curvature, said breech rails providing a circular row of equally arcuately spaced individual firing stations, and said breech structure having a back breech rail connecting corrresponding ends of said top, bottom and side breech rails, said back breech rail having a front wall surface at right angles to said top, bottom and side rails and having a plurality of firing means, one at each firing station, associated with said front wall surface and concentric with said arcuate breech surfaces; an ammunition drum-gun barrel assembly comprising a cylindrical ammunition drum co-equal in radius of curvature with said arcu'ate breech surfaces, mounted for rotation on its cylinder axis concentrically with said arcuate breech surfaces, said drum having a circular row of equally angularly spaced radially arranged open ammunition chambers arranged around its circumference for the reception successively individually of a round of ammunition between each firing station and the next succeeding station in the direction of rotation of said assembly, and for closure successively individually by said arcuate breech surfaces individually at said firing stations, and gun barrels, one for each chamber, carried by said drum for rotation therewith, said barrels being arranged in a circular row concentric with said cylinder axis; electric motor means operatively coupled to said drum-barrel assembly for rotating said assembly; and reaction means powered by firing gases from said barrels for supplying a supplementary rotational force to said assembly during firing.

11. A multi-barrel gun in accordance with claim 10 including reduction gearing between said electric motor means and said drum-barrel assembly.

12. A multi-barrel gun in accordance with claim 11 in which said electric motor is mounted to said back breech rail and interiorly of said drum, and in which 13 said reduction gearing includes a ring gear carried by said drum.

13. A multi-barrel gun in accordance with claim 10 in which said reaction means comprises a multi-st-age turbine including a plenum chamber carried by said drum for conducting-firing gases from said barrels to the first stage of the turbine.

14. A multi-barrel gun in accordance with claim 13 in which said multi-stage turbine comprises an inner set of turbine rotors carried by said electric motor means and an outer set of turbine rotors carried by said drum.

15. A multi-barrel gun in accordance with claim 10 in which said firing means are electrical.

References Cited in the file of this patent UNITED STATES PATENTS Dardick Aug. 19,

Otto Sept. 2,

OBrien Nov. 8,

OBrien Feb. 14,

Marquardt Feb. 21,

FOREIGN PATENTS Great Britain Mar. 5,

Images