Automatic firearm construction
United States Patent 1 in] 3,875,845  
 Hupp et al. Apr. 8, 1975 AUTOMATIC FIREARM CONSTRUCTION weapon, comprises a cartridge feeding system which [75] Inventors: Gerhardt Hupp,Obcrndorf. Neckar; gr i s? l g l re clprocatm g ifi Helmut Mad&#34;. schmmbergi both uf 0c 0 cc a series 0 car r1 ges lfl succession 0 e German cartridge chamber of the gun barrel under the control of gas pressure which is generated during the firing of [73] Assignec&#39;. lndustrier e each cartridge. A cartridge feeding device for the gun Karlsruhe-Augsburg AG. Karlsruhc. includes a multi-operable cartridge magazine which Germany has a plurality of rotatable stars arranged at trans- [22] Filed: Jan. 4 I974 versely spaced locations and which may be shifted selectively into operative positions in which a rotatable l l PP N06 430-603 shaft portion becomes automatically coupled to a coupling and indexing mechanism which is carried on the [30] Foreign Application Priority Data gun. The coupling and indexing mechanism comprises J 7 G I I q q a rotary portion which is rotated upon movement of a l9 ermm) 3 piston member which is connected during the firing to the pressure gases so that it is shifted to effect rotation 89/33 ga 3 of the coupling. The coupling is connected to the shaft l of the indexing star which is in the operative position held or seanh 89/33 33 gg lj so that the cartridges of this portion are fed in succession to the cartridge chamber of the gun barrel. The  
  References Cited construction perm|ts shifting from one rota a e car FORElGN PATENTS OR APPLICATIONS 1206.025 9/l97t) United Kingdom 89/33 BC Primary E.\&#39;uminerStephen Ct Bentley Attorney, Agent, or FirmMcGlew and Tuttle [57] ABSTRACT An automatic firearm, particularly a gas operated tridge supplying star system to another or to a system in which the cartridges are fed either by the rotatable star or by a magazine clip which feeds the cartridges directly downwardly to a position in which they are moved to the cartridge chamber.  
 6 Claims, 5 Drawing Figures PATENIEDAPR saws SuLU 1 UP 5 AUTOMATIC FIREARM CONSTRUCTION FIELD AND BACKGROUND OF THE INVENTION This invention relates in general to the construction of firearms and. in particular. to a new and useful firearm which includes a cartridge feeding system which includes at least two rotatable star feeding mechanisms for separately feeding cartridges. for example. from a continuous belt and which may be selectively positioned in an operative position in which they become coupled to the indexing mechanism of the gun for feeding the cartridges to the cartridge chamber for firing.  
 DESCRIPTION OF THE PRIOR ART In action. particularly with heavy rapid-fire weapons. such as automatic 2() to 30 mm guns for explosive projectiles having a high initial velocity. it is frequently necessary to attack in immediate succession living targets with highly explosive shells and armored targets with armor piercing shells. To effect this ammunition change in conventional weapons. the entire cartridge belt must be removed in a complicated and time consuming manner and replaced by another with the desired ammunition.  
  To remedy this shortcoming. devices are known which permit feeding of one sort of cartridge by means of belts and another by means of attachable magazines. Such devices. however. have a limited storing capacity for the second sort of ammunition. for example. armorpiercing ammunition.  
  There is further known a weapon (Stoner) which is equipped with two separate feeding mechanisms mounted on the left and right-hand sides and adapted to introduce belts with different sorts of ammunition.  
 for example. cartridges with explosive projectiles and cartridges with armor-piercing projectiles. In this construction. both feeding mechanisms are mounted on a common base. which is pivotable in respect to the weapon housing to such an extent that the forwarding breech block seizes either cartridges coming from the left. for example. with armonpiercing projectiles. or cartridges coming from the right with explosive shells. Even though. in this case. a selective firing of two different sorts of ammunition is possible without changing the belt. the construction is too expensive and complicated. Another drawback of this construction is that the second sort of ammunition. contrary to the intended tactical purpose. does not become effective immediately after the switching over of the cartridge feeding mechanism because one cartridge of the other sort of ammunition is fed in before the switching is still in the barrel and must be fired first. In action. this is highly undesirable. if only because thereby. for example. when using tracer ammunition or the like. one s own emplacement or location may be betrayed to the enemy.  
  The present invention is directed to the problem of eliminating such drawbacks and disadvantages of the known weapons and of providing a cartridge feeding device permitting the switching over from one sort of ammunition to another within a minimum of time and with relatively small forces and assures that after the switching operation. the following first shot is done with the desired or required other ammunition.  
 SUMMARY OF THE INVENTION In accordance with the present invention. this problem is solved substantially by providing a cartridge feeding device comprising two parts of approximately identical mirror opposite design serving to receive different sorts of ammunition and positioned parallel to the longitudinal axis of the weapon. the switching over from one sort of ammunition to the other being effected by shifting the device transversely to the longitudinal axis of the weapon. whereby. with the aid of a mechanism associated thereto. the device is automatically coupled to. or uncoupled from. a mechanism which is mounted in front of the cartridge feeding de vice in the direction of the muzzle and which. under the action of the gas pressure supplied thereto during the backward motion of the breech block and while coupled to the respective selected part of the cartridge feeding device. effects the transfer of the cartridge received in the feeding belt into the cartridge chamber of the weapon.  
  According to a development of the invention idea. the mechanism mounted in front of the cartridge feeding device in the direction of the muzzle includes a piston subjected to gas pressure and comprising a rack portion or the like permanently meshing with a pinion. To assure the operation of the mechanism in accordance with the invention and thereby the switching from one sort of ammunition to the other. the pinion meshing with the rack is permanently in gear with a second pinion. Both of the pinions in mesh with each other are provided with simple coupling means which are highly reliable in operation and each serve to be coupled to. or uncoupled from. a selected one ofasially movable and conformably designed shafts forming a part of the cartridge feeding device. The coupling means on the pinions comprise T-shaped grooves with which the conformably designed shafts may be engaged or from which they may be disengaged by shifting. in order to change the sort of ammunition.  
  By an appropriate application of the main idea of the invention. the possibility is given. of course. to provide a firing of more than two different sorts of ammunition in the same simple manner. This can be achieved. in accordance with the invention. by providing a bar-type magazine or the like mounted between the approximately reflex-designed halves of the cartridge feeding device.  
  The present invention offers many advantages which cannot be disregarded:  
  The switching over from one sort of ammunition to another is carried out with relatively simple but highly effective and rugged means. This is an indispensable condition for assuring the operation of the weapon in action. even under extremely difficult circumstances.  
  Aside from the fact that by using the inventive arrangement it is easily possible to provide for the firing of even a third sort of ammunition. the feeding of the cartridge belt is independent of the breech block and effected by the gas pressure acting on a special piston which. for space-saving and other similar reasons. is also in the form of a rack.  
  The highly space saving and narrow construction of the cartridge feeding device. in accordance with the invention. is of particular importance. This is possible due to the arrangement whereby the cartridge to be introduced into the cartridge chamber is delivered to an offset position relative to the longitudinal axis of the weapon. Not less important is the advantage that after the switching over from one sort of ammunition to the other, the very next fired cartridge is already of the se lected new sort of ammunition.  
  Accordingly. it is an object of the invention to provide a firearm construction which includes a coupling and indexing mechanism which is operated upon the firing of each cartridge and which has a rotatable coupling part which is selectively coupled to one of a plurality of separate cartridge feeding stars or indexing mechanisms of a cartridge feeding system which includes two or more transversely oriented cartridge feeding systems which may be selectively placed in an operative position.  
  A further object of the invention is to provide a weapon which is simple in design. rugged in construction and economical to manufacture.  
  For an understanding of the principles of the invention. reference is made to the following description of typical embodiments thereof as illustrated in the accompanying drawings.  
 BRIEF DESCRIPTION OF THE DRAWINGS In the Drawings:  
  FIG. I is a partial vertical sectional view of a firearm ha\ ing a cartridge feeding device constructed in accor dance with the invention:  
  FIG. 2 is a top view of the firearm shown in FIG. 1; FIG. 3 is a section taken along the line [3-8 of FIG. I;  
  FIG. 2&#39;. and  
  FIG. is a view similar to FIG. 4 of another embodiment of the invention.  
 GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in particular. the invention embodied therein in FIGS. 1 to 4. comprises a firearm having a barrel 50 with a bore axis 1.  
  In accordance with the invention, the weapon is pro vided with a cartridge feeding device. generally designated 2, which as best indicated in FIG. 4 contains two separately operable cartridge feeding mechanisms or cartridge feeding stars 4 and 4 which are adapted to be connected through a coupling and indexing mechanism. generally designated 8, to provide for a selective feeding of cartridges from a continuous supply or belt or a continuous supply or belt 15&#39;.  
  As shown in FIG. 1. the feeding device 2 is constructed to receive and feed a series of cartridges 3 by the rotation of a feeding star 4 into a cartridge chamber 5. The cartridge feeding mechanism 2 is held in posi tion over the rifle barrel 50 by a bolt 6 which is hinged to an eye 21! of the cartridge feeding device 2 and engages into a stationary eye 7 which is mounted on the combination coupling and indexing device 8. Suitable means on the eye 7 are provided for clamping the bolt 6 in a fixed axial position.  
  In accordance with a feature of the invention. the operating star mechanism 4 and the operating star mechanism 4&#39; each include an axially movable shaft 2b which has a coupling part or T-shaped coupling portion at its end which is adapted to be coupled selectively to the coupling and indexing means 8 in accordance with which ofthe feeding stars 4 or 4&#39; is to operable. For this purpose. the coupling and indexing mechanism 8 includes coupling elements 80 and 8b which are under the biasing influence ofa torsion spring 9 to urge them 4 is a section taken along the line CC of FIG.  
 into a position in which they are engageable with the couplings 8a or 812 of the shaft 2b or 2b of the respective star mechanism 4 and 4&#39;. The coupling means and the spring 9 are mounted in bushings 8c and 8d and the outer circumferences of the bushings 8c and 8a are provided with teeth 8e and 8f. respectively. so that they form pinions which are engageable with a piston rack member II, as shown in FIG. 3. The coupling and indexing mechanism 8 is fixed to the top of the stock 52 of the weapon so that it overlies the barrel 50 in the vicinity of the cartridge chamber 5. The cartridge feeding device 2 is shift-able transversely to the longitudinal axis of the weapon as indicated by the double arrow in FIG. 2. A guide pin 10 is mounted in the eyes 2a arranged at each end of the feeding device and it is slidably guided in a sleeve 8;; which is affixed to the coupling mechanism 8. The sliding motion takes place when the cartridge feeding device 2 is shifted transversely in order to change from one type of ammunition to another.  
  The coupling and indexing mechanism 8 includes a piston 11 which is slidable in a housing portion 8a of the coupling and indexing mechanism transverse to the main axis or bore axis 1. The piston 11 is shaped as a rack Ila and this rack portion meshes with the teeth of a pinion 8e which is also in meshing engagement with a pinion 8f. The pinion 8e and Sfare provided with coupling parts 8a and 8b which engage with the T-shaped coupling parts 2(&#39; of the shaft 2b or 211&#39;.  
  During operation of the weapon a breech block. which is not shown. moves backwardly after the firing of each cartridge. The firing of the cartridge produces a pressurization ofthe cylinder 8/: containing the piston 11 due to flow of the gases through passages 12, I3 and 14, so that the piston 11 moves to the right. as indicated in FIG. 3. This shifting of the piston 11 produces a rotary movement of a coupling part through the pinions 8c and 8f so that the shaft 211 which is coupled thereto is rotated also. This rotation of the shaft 2b provides a rotation of the feeding star 4 so that the cartridges 3 which are contained in a belt 15 are advanced to a position in which they are deposited into the barrel chamber S. In the position of the cartridge feeding device 2 shown in FIG. 4. the belt 15 is in an operating position in which it is being moved by the star 4. When the cartridge type is to be changed. the cartridge feeding mechanism 2 is shifted to the left or the dotted line position shown so that the star 4&#39; is moved into an operative position. The cartridge 3, which is transported by the feeding star 4, shown in the solid position of FIG. 4, is mo\ ed downwardly in the direction of the black arrow 54 until it is positioned close to the inlet opening leading to the cartridge chamber 5, as shown in FIGv 1. In order to obtain the smallest possible shifting distance of the cartridge feeding device 2, the central axis of the feeding star in the final or operative position is located laterally offset with respect to the central axis of the weapon and by an amount equal to the distance y. Thus. the delivery of the cartridge 3 into the cartridge chamber 5 takes place in a position within the feeding star 4 corresponding to an angular deviation by the amount of the angle or shown in FIG. 4. Consequently, if the axis-to-axis distance of the two feeding stars 4 in .t, as shown in FIG. 4, the transverse shifting distance of the cartridge feeding device is a distance equal to minus the distance 2y. The cartridge 3 to be introduced into the cartridge chamber 5, as shown in FIG. 1, per- 5 forms because of its offset position by the angle a a lateral and simultaneously downward movement. By such an arrangement. it is possible to shorten the distance in which the feeding mechanism 2 need be shifted and. in addition. this shortens the time required for a changeover from one type of ammunition to another.  
  While the belt is being fed in the direction of the arrow 54 into the cartridge chamber. the empty belt is moved off in a direction of the white arrow 56. The angle B indicates the possible range in which the belt 15 may be removed either in a direction directly upwardly or in a direction substantially horizontally.  
  When the center line of the Cartridge feeding device 2 is vertically aligned with the central axis of the weapon. the position of the device is a neutral position and the cartridges 3 cannot be delivered into the car tridge chamber 5 either from the left or from the righthand side. In consequence. this intermediate neutral position of the cartridge feeding device 2 provides an additional safety measure in respect to the use of the weapon.  
  The construction and operation of the cartridge feeding mechanism indicated in FIG. 5, and generally designated 2&#39;. is substantially the same as that shown in FIG. 4 but in addition to the two feeding stars 40 and 41:, there is provided a bar-type magazine feed 16 which is mounted between housings ofthe stars 4a and 4a. Ammunition l7 placed in the magazine 16 may be. for example. a type of ammunition referred to as indicator ammunition, and this may be used selectively between the firing of one magazine portion or the other for purposes of marking a target.  
  While specific embodiments of the invention have been shown and described in detail to illustrate the application ofthe principles of the invention. it will be understood that the invention may be embodied otherwise without departing from such principles.  
 What is claimed is:  
  1. An automatic firearm. particularly a gas-operated firearm having a reciprocating breech block and a cartridge feeding device which is controlled by the gas pressure during the firing ofa cartridge to feed a series of cartridges in succession to the cartridge chamber of a gun barrel. comprising a coupling and indexing mechanism including a member shiftable by gas pressure generated by the firing of a cartridge and a rotatable coupling part connected to said member and rotated thereby. a cartridge feeding device including a transversely movable housing with first and second transversely spaced rotatable cartridge feeding stars which are rotatable to feed cartridges in succession to the bar rel cartridge chamber. said cartridge feeding device being shiftable to align a respective one of said first and second stars in operative positions in respect to said rotatable coupling and the cartridge chamber. said stars being selectively and alternatively alignable in an oper ative position and each star having a shaft with a coupling portion which is separately engageable with said rotatable coupling when in an operative position whereby to connect the associated star so as to feed the ammunition to the cartridge chamber.  
  2. An automatic firearm. according to claim I. wherein said coupling and indexing mechanism in cludes a cylinder. said member comprising a piston shift-able in said cylinder. means for connecting gas pressure generated in the gun barrel cartridge chamber during the firing of a cartridge to said cylinder to displace said piston. said piston being connected to rotate said rotatable coupling.  
  3. An automatic firearm. according to claim 2. wherein said piston includes a rack portion. said rotat able coupling part comprising a pinion in meshing engagement with said rack portion.  
  4. An automatic firearm. according to claim 3. wherein each of said first and second rotatable stars includes a central rotatable shaft having a shaft coupling formation at its end. said shaft coupling formation being engageable with said rotatable coupling. said rotatable coupling comprising first and second rotatable gears engageable with said rack.  
  5. An automatic firearm. according to claim 1, wherein said rotatable stars each include a shaft coupling part having a T-shape groove.  
  6. An automatic firearm. according to claim 1. including a bar-type magazine located between said rotatable stars for receiving a third type of ammunition and having a downwardly feeding discharge for the cartridges located between said first and second stars.  
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