WO1987000613A1

WO1987000613A1 - A disc magazine firearm

Info

Publication number: WO1987000613A1
Application number: PCT/AU1986/000206
Authority: WO
Inventors: Charles Giorgio
Original assignee: Armtech Limited
Priority date: 1985-07-19
Filing date: 1986-07-18
Publication date: 1987-01-29
Also published as: EP0233222A1; EP0233222A4

Abstract

A firearm which fires projectiles (70) from a demountable disc magazine (63) for caseless ammunition rotatable about an axis transverse to the axis of the bore of the firearm barrel (2). The firearm has a gas reciprocated barrel assembly including mounting (35, 36, 38) means for a magazine, a bi-directional reciprocating cycle of the barrel assembly moves a magazine positioner (24) through a lock-unlock-lock sequence and a magazine (63) when mounted in the firearm into and out of engagement with a magazine indexing means (66) whilst the positioner (24) is unlocked in order to sequentially align peripheral projectile apertures (69) in the magazine with the bore of the firearm barrel (2).

Description

" A DISC MAGAZINE FIKEABM"^"

This invention relates to firearms, and in particular to firearms of the self loading type which use gas generated at one firing of the firearm to reload the firearm for the next firing. The invention differs from known self loading firearms as described below principally in that it fires caseless ammunition.

Conventional cased ammunition for gas powered self loading firearms comprises a cartridge case having an open end in which the projectile is mounted and the propellant for the projectile is ho sed- in the.case. There is a primer mounted * in the case which upon being stuck causes the propellant^' to ignite. The cartridge case includes a peripheral groove adjacent its closed end to facilitate the extraction of a case after the firing of the firearm.

Firearms for use with the above ammunition have a reciprocating bolt carrier with an associated bolt to load and retain the cartridge in the firing chamber of the firearm whilst it is fired and then extract and eject the cartridge case after firing. The extraction and ejection is achieved by devices on the bolt and ejection of the case from the firearm is through an ejection port in the firearm upper receiver. There are drawbacks with firearms as just, described, for example they are relatively long. The firearm body has to be long enough to cater for the travel of the bolt, to this is added the length of the barrel and the stock. There can be operational difficulties. The extraction and ejection mechanisms can on occasions malfunction, often because of differences in or quality of the ammunition used. The ejection at speed of spent cases from the firearm is hazardous to persons adjacent the firearm during firing and when the firearm is used in confined spaces.

The present invention- overcomes all of the above problems by. providing a firearm which does not have a reciprocating bolt carrier and which uses caseless ammunition.

Broadly, the invention can be said to provide a disc magazine firearm wherein the disc magazine is demountable and houses caseless ammunition and is rotatable about an axis transverse to the axis of the bore of a barrel of the firearm, the firearm barrel with associated magazine support means is reciprocatable and a bi-directional reciprocating cycle of the barrel assembly moves a magazine locator through a lock-unlock-lock sequence and a magazine when mounted in the firearm into and out of engagement with a magazine indexing means whilst the locator is unlocked thereby to sequentially align peripheral projectile apertures in the magazine with the bore of the firearm barrel, gas operated means and manual means to reciprocate the barrel and trigger and hammer means to fire projectiles from a magazine mounted in the firearm down the bore of the firearm barrel .

A presently preferred form of the invention will now be described with reference to the accompanying drawings in which:-

Fig.l is a side elevation of the firearm, ✓_jQ Fig.2 is an end view from the muzzle end of the firearm, Fig.3 is a side elevation with part of the housing removed so the interior of the firearm can be seen, Fig.4 a sectional view of the front support for the barrel when .in a forward position,

Fig.5 is a view similar to Fig.4 when the barrel is moved rearwardly to disengage the piston and cylinder of the front barrel support,

Fig.6 is an exploded and fragmentary view of the several components that make up the operating mechanism of the 20 firearm,

Fig.7 is an edge view of a magazine for the firearm, Fig.8 is a section through the centre of the magazine of Fig.7,

Fig.9 is fragmentary and schematic view of the hammer in a rest phase with the magazine removed from its support, Fig.10 is a view similar to Fig.9 of the hammer when in a cocking phase and

Fig.11 is a view similar to Fig.9 with the hammer having just struck the firing pin.

From Fig. 1 it will be seen that the firearm comprises a - housing 1 which is in the form of an extruded aluminium tube of cross-sectional shape as shown in Fig.2. The general arrangement of the firearm components can be seen from Fig.3. Inside the housing 1 there is a barrel 2 with a front support 3 the details of which can be best seen from • Figs.4 and 5. It comprises a stepped piston having a small cylindrical portion 4 and a larger diameter portion 5. There are grooves 6 around the piston steps. There are ports 7 in the piston for gas flow from the bore of the barrel to the surface of the piston.

The piston is supported in a cylinder 8 having threaded tubular spigot 9 projecting through a bracket 10 and secured in place by the nut 11. The bracket 10 has legs 12 secured as at 13 to the housing. The cylinder 8 has a small diameter bore 14 and a larger diameter bore 15 to slidingly receive the piston portions 4 and 5. It is to be noted that with the end of the piston portion 4 at the bottom of the cylinder bore 14 there is a gas chamber 16 provided between the end of the piston portion 5 and the shoulder 17 and that the chamber is aligned with the ports 7. At the rear end of the barrel 2 there is a magazine mount. The details of this are best shown in Fig.6. where it will be seen that the rear end of the barrel is threaded at 17 for engagement in the threaded bore 18 of the barrel extension 19. The end 20 of the barrel part 17 will be just level with or slightly above the surface 21 of the barrel extension 19.

Fixed to the barrel extension 19 there is a guide 22 with a cylindrical bore 23 with an axis co-incident with the axis of the barrel bore and at right angles thereto. Adapted to be slidingly mounted in the bore 23 there is a magazine positioner 24 with a diametric hole 25 therethrough and a profiled end 26 as will hereinafter be described. The guide 22 has upper and lower slots 27 aligned with the axis of the bore of the guide 22. The positioner 24 has a cam pin 28 fixed in the hole 25 and engaged in the slots 27 whereby the positioner can be guided in a path of limited length in a direction at right angles to the axis of the barrel bore.

The upper end of the pin 28 extends above the guide 22 and is engaged in the cam track of the member 29 which is fixed to the inner surface of the housing 1. It will be noted that the track includes two laterally spaced straight portions 30 aligned with the axis of the barrel bore and a joining section 31. It follows therefore that if the barrel extension is moved to and fro in the direction of the axis of the barrel bore the positioner 24 would be moved to and fro in the guide 22 by the inter-action between the cam track sections 29 to 31 and the cam pin 28.

Fixed by screws to the side face 33 of the barrel extension 19 there is an arm 34 with a hooked free end 35 which corresponds with the-hooked end 36 of a like arm part 37 of the guide 22. Pivotally secured to the arms 34 and 35 and spring biassed to a position where they partly intrude into the part-circle cutouts of the ends 35 and 36 there are arms 38. The arms 38 are principally to releasably mount a magazine to be described in the assembly, as will hereinafter be described.

There are laterally extending pins 39 on the arms 34 and 37 and rollers 40 rotatably supported on the pins 39 are engaged in channel tracks 41, see Fig.3, to provide the rear support for the barrel as it is moved backwards and forwards. On the arm 34 there are also upper and lower mounting lugs 41 and 42 and pair of spacers 43 and the body of hammer 44 are mounted on a pin 45 fixed in the lugs 41 and 42. There is an end lug 46 on the arm 34 with a hole 47 therethrough and one end of a spring arm 48 is pivoted at its other end at 49 to the hammer 44 and extends through the hole 47. The spring 50 between the head 51 of the pin arm 48 and the lug 46 urges the hammer 44 in an anti-clockwise direction .

Other aspects of Fig.6 are the details of the trigger mechanism. There is illustrated an operating bar 52 which is supported in the slot 53 in the lug 46 so it has limited lateral movement in the slot and an offset trigger 54 to which one end of the trigger bar 52 is pivotally connected at 55. Not shown is a torsion spring in the connection 55 which urges the bar 52 in a clockwise direction to cause it to resiliently bear on the end 82 of the slot 53.

The inter-relationship of the foregoing can be readily seen frςim Fig.3 where the suppor-t for the trigger 54 in the housing 1 is shown. It comprises a bar 56 pinned to the trigger 54 and slidingly housed in part of the handgrip/trigger guard 57. There is a compression spring 58 uging the trigger 54 towards the muzzle end of the firearm against a stop shoulder 59 at the end of a slot 60 in the housing 1 through which the trigger finger grip 54 extends to the outside of the housing. A firing pin housing 61 is fixed at 62 to the arm 34.

Referring now to Figs.3, 7 and 8, the magazine comprises a disc 63 with a flat side 64, facing towards the viewer in Fig.3. Equally spaced around the periphery of the disc adjacent the side 64 there are thirty indexing notches 65 which are so arranged that each time the barrel assembly moves rearwardly to a predetermined extent an indexing finger 66 pivotally mounted on the housing at 67 and spring biassed to a rest position engages a notch 65 and rotates the disc 12 degrees.

The opposite side of the disc 63 has thirty radially extending bosses 68 formed thereon, the edge view Fig.7 and the sectional view Fig.8 when read with Fig.3 where two bosses 68 are shown in dotted lines will enable the configuration of the bosses 68 to be visualised. It is to be noted at this time that the profiled end 26 of the positioner 24 is intended to be a very close fit over a boss

68. *-Each boss 68 has an internal configuration as shown in Figiδ", comprising a radially extendi-ng -proje.ctile aperture

69, projectile 70 being shown therein, a propellant cavity 71 and a primer hole 72. It will be noted from Fig.3 that the primer holes are on a pitch circle such that they will pass below the firing pin 73 mounted in the housing 61 and spring biassed to the "out" position by the spring 74.

In an operating sequence, assuming the magazine is in the firearm with the magazine axles 86 in the hooked bearings 35 and 36 and with the magazine part loaded. There would be a need to manually index the magazine to place a projectile in line with the barrel bore. This is achieved by the-use of the cocking handle 75 slidably mounted in a slot 76 in the. housing and spring biassed by the spring 77 to the muzzle end of the slot 76. There is an internal rearwardly extending arm 78 on the cocking handle 75 which will on rearward movement of the cocking handle end engage a lug 79 on the barrel piston assembly.

The rearward movement of the barrel assembly will cause the pin 28 to- move along the cam track portion.30 and then 32 to disengage the cavity 26 of the positioner 24 from a boss 68. At this time the hammer 44 will be moving with the barrel extension from the position shown in Fig.9 to disengage the operating end 80 of the trigger bar 52 from the shoulder 81 of the hammer boss. It is to be noted here that the spring 74 on the firing pin is strong*.enough to resist the pressure exerted by the hammer spring -50^' in it substantially fully extended condition and therefore the striking end of the striking pin remains within the housing 61, see Fig.9. Because of the torsion spring in the trigger bar hinge 55 the bar 52 will remain urged against the side 82 of the opening 53 of the lug 47, this is its rest position where it is aligned with the hammer shoulder 81.

Towards the end of the rearward movement of the cocking handle 75 with the cam pin now in the cam track portion 31 a magazine indexing notch 65 will be engaged by the indexing finger 66 to rotate the magazine axles- 86 in the bearings 35 and 36. The indexing is a specific number of degrees and the spring loaded members 38 bearing on the axles 86 substantially prevent over-run. When the cocking handle is released the compression spring 83 around the.barrel and between the circlip 84 and the forward end of the front barrel support will return the barrel to the forward position, the cocking handle spring 77 does the same for the cocking handle.

In returning to the forward position the barrel moves the cam pin along the cam track and the positioner is thrust home around the next boss. The profile of the bosses and the mating recess 26 are such that any slight rotational mis-alignment of the next projectile aperture with the barrel bore will be corrected. The trigger bar will again be in the position shown in Fig. 9 that is with the end^' 80 slightly spaced from the shoulder 82.

Assuming now that there was a projectile aligned with the barrel bore and the firearm is to be fired. It will be noted that at this time the boss 68 from which the projectile is to be fired is within the recess 26 of the positioner 24 and the back of the boss, that is the face 64 of the magazine behind the boss 68, is supported by the inner face of the arm 34. Accordingly, the material enclosing the propellant is substantially fully supported to withstand the pressures developed during the. firing of the bullet. Accordingly, disposable magazines of plastics material could be used in a firearm as proposed. Rearward pressure on the trigger will engage the bar end 80 with the shoulder 81. Continued rearward movement of the. bar 52 will cause the hammer 44 to be rotated about the pin 45 until the bar end 80 leaves the shoulder 81. There is a set of opposing forces operating at this time, see Fig.10. The spring in the hinge 55 is acting in the direction of the arrow A urging the bar 52 against the end 82 of slot 53 and the bar 52 is being pushed in the direction of the arrow B across the opening 53 as it leaves the shoulder 82. By the time the separation of the members 80 and 81 occurs the hammer spring 50 will be well tensioned and as the end 80 releases the hammer shoulder 81 the hammer 44 slaps back with great force against the firing pin 73, overcoming the effect of the firing pin return spring 74, and driving the operating end of the firing pin into the primer to ignite the propellant in the chamber 71.

The gas generated by the propellant burning drives the projectile along the barrel bore and some of the gas in the barrel bore behind the projectile passes into the gas cocking chamber 16. The cycle of events described with reference to the manual actuation of the cocking handle is now performed by the gas in the piston and cylinder assembly to align the next projectile with the barrel bore. The bar 52 will now be in the position shown in Fig.11 and when released the trigger will move forwardly under the action of its sring 58. The spring in the pivot connection 55 will, when the end 80 has cleared the shoulder 81, return the bar end 80 to the Fig.9 position.

The removal of the magazine is accomplished in the foregoing embodiment with the barrel held in the rearward position by the cocking handle and by then applying pressure on the ejector flap 85, which is resiliently retained in closed condition by the spring for the indexing member 66, to bring the flap to bear on the magazine. Depression of the flap is continued until the magazine axles are forced free of the spring fingers 38. The magazine would then fall freely from the firearm through the opening 87 in the firearm body. A fresh magazine could then be inserted and driven up into the bearings by a push with the palm of a hand and the cocking handle would then be released.

Claims

THE CLAIMS

1. A disc magazine firearm wherein the disc magazine is demountable and houses caseless ammunition and is rotatable about an axis transverse to the axis of the bore _r of a barrel, of the firearm, the firearm barrel with associated magazine support means is reciprocatable and a bi-directional reciprocating cycle of the barrel assembly moves a magazine locator through a lock-unlock-lock sequence and a magazine when mounted in the firearm into and out of engagement with a magazine indexing means whilst the locator is unlocked thereby to sequentially align peripheral projectile apertures in the magazine with the bore of the firearm barrel,^" gas operated means and manual means _*to reciprocate the barrel and trigger and hammer means to fire projectiles from a magazine mounted in the firearm down the bore of the firearm barrel.

2. A disc magazine firearm where the disc magazine rotates about an axis at right angles to a bore of a barrel of the firearm and the magazine comprises a body with two sides and a circular periphery concentric with a hub means, a plurality of equally spaced apertures for projectiles positioned around the periphery of the body, powder chambers within the body respectively interconnected with the apertures, primer holes in one side of the body equally spaced around a pitch circle concentric with the hub means - 14 -

and respectively interconnected with the chambers, locators on the other side of the body having predetermined relationships with the respective apertures and indexing means equally spaced around the body; said firearm comprising a tubular housing, first support means fixed in the housing adjacent one end thereof and a second support means fixed in the housing adjacent the other end thereof, an elongated bored barrel, a piston and cylinder interconnection between the barrel adjacent one of is ends and the first support means into which gas produced during the firing of a bullet is directed to cause the barrel to slide rearwardly in the first support means away from a . barrel rest position to an indexing position where an indexing finger mounted in the- ousing^'will engage the indexing means of a magazine when mounted in the firearm, and spring means to return the barrel in a forward direction to its rest position, a magazine mount at the other end of the barrel adapted for sliding engagement in the second support means, the magazine mount comprises a barrel extension fixed to said other barrel end, a magazine positioner slidably mounted in a guide part of the barrel extension so as to be movable in a direction lateral to the axis of the bore of the barrel, a cam pin fixed to the magazine positioner and engaged in a cam means fixed to the housing whereby londitudinal movement of the barrel assembly will cause sliding movement of the magazine positioner between a first lock and locate position where it engages a locator of a magazine when mounted in the firearm to align a projectile aperture with the bore of the barrel and an outer magazine release position, a hub support means on the barrel extension to rotatably and releasably retain a magazine by its hub, a firing pin mounted on the barrel extension and a hammer assembly including a hammer to drive the firing pin into engagement with magazine primers, and a trigger assembly on the housing to cock and release the hammer..

3. A firearm as claimed in claim 2 wherein the first support means comprises a bearing bracket fixed internally in the housing, a bearing in the bracket, a primary bore in the bearing in which the barrel can slide, a cylindrical bore"enlargement at one end of the bore to provide a cylinder, a piston around said barrel to engage in said cylinder and gas port means between the periphery of the piston and the barrel bore.

4. A firearm as claimed in either of claims 2 or 3 wherein the magazine positioner was a cross-section substantially the same as that of a bore in said guide member which includes track means extending laterally to the axis of the barrel bore and guide pins extending from the magazine positioner are engaged in the track means.

5. A firearm as claimed in claim 4 wherein the magazine positioner is cylindrical and the track means comprises diametrically opposed slots in the wall of the guide member and the guide pins comprise ends of said, cam pin which also extends beyond said guide member and is engaged in said cam means.

6. A firearm as claimed in anyone of claims 2 to 5 wherein the 'magazine positioner has a working end with a recess therein dimensioned to engage over successive locator bosses on said other side of-a magazine body, each boss comprising the walls around a major part of one of said chambers.

7. A firearm as claimed in anyone of claims 2 to 6 wherein the. cam means comprises a cam track with two laterally spaced straight portions parallel to the axis of the barrel bore and an interconnecting portion.^'

8. A firearm as claimed in anyone of claims 2 to 7 wherein the hub support means comprises two arms each with a notch to respectively receive the ends of a magazine hub with spring loaded catch means to releasably retain the hub ends in the notches.