Abstract:
A lightweight weapon housing system is disclosed for a self-loading firearm. The weapon housing includes an outer and an inner housing. A wall structure in the weapon housing reinforces the magazine chamber and transmits the transverse forces arising in the magazine into an inner housing, which suffers any resulting deformation and which can be exchanged in a simple manner should deformation result.

Description:
RELATED APPLICATION 
     This patent claims priority under 35 U.S.C. §120 and is a continuation from co-pending International Patent Application Serial No. PCT/EP00/00600 which was filed on Jan. 26, 2000. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to self-loading firearms, and, more specifically to a housing system for an automatic self-loading rifle or pistol. 
     BACKGROUND OF THE INVENTION 
     For a long time, self-loading rifles have possessed a component which receives a movable breech, which was either forged or machined out of a solid block. The machining for such a component, which formed a primary structural part, required a great expenditure of craftsmanship. On the outside of these breech sections were affixed many functional elements of the weapon. The practice of stamping weapon housings out of sheet metal did not start until the end of the thirties. These sheet metal housings could be fabricated much more quickly and less expensively than before, and yet surrounded most of the functional elements like a shell skeleton. The functional elements were also placed in the interior of the housing, and on this account were protected from damage and contamination. Sheet metal housings have, unfortunately, often been undesirably heavy, particularly with weapons of large dimensions. This weight problem is exacerbated when a particular zone must be reinforced, which usually was carried out by welding on reinforcing members. 
     Recently, to reduce the weight of the weapons, weapon housings have been made of plastic. In the zones exposed to the principle stresses, however, metal sheathing is once again being used, thereby drastically increasing the weight of the weapon. 
     For utility weapons, such as are employed for military or police applications, the design effort has been toward weapons of the least possible weight. 
     One of the main loading factors for the weapon housing is the abutment support of the closure spring of the breech. Fortunately, the spring forces of the breech closure act in the longitudinal direction of the housing, and are therefore well transmitted to the housing walls surrounding the breech spring. More dangerous for the structural strength of the housing, however, is a possible deformation which may be caused by the magazine. The magazine forms a long, lever arm, extending out of the housing from the magazine chamber. This chamber is constructed in the housing and, in the most simple case, is principally an opening, which corresponds to the cross-section of the magazine. 
     The cross-section of the opening must be large enough to fit the lengths of the provided cartridges. Therefore, the longer the cartridge, the longer the cross-section of the opening must be, which makes the housing more susceptible to twist, since the opening of the magazine chamber breaks the structural advantage of the closed box cross-section of the housing. In order to provide the area of this opening with greater structural strength, the opening is typically encased with a wall structure, which then borders the opening. 
     This stiffening measure, however, has not always been sufficient. This is particularly the case, when the magazine protrudes out of the housing, and when this protrusion is of a substantial length. In such a case, a more or less transverse loading on the free end of the magazine can lead to the imparting of very high forces to the magazine chamber. This can occur, for instance, if the weapon falls from the bed of a truck to the ground, and then, unfortunately, the magazine separates. An unreinforced, especially thin walled housing can then be bent or even develop fissures. 
     In the case of a large caliber, self-loading firearm designed for firing shell type munitions with a caliber of some 20 mm, due to the large cartridges which are employed, all parts are inordinately large and heavy. However, a given allowable weight for a user must not be passed. The difficulties arising from this body of problems are increased, when the large caliber rifle carries attached equipment, such as a rapid-fire-system. 
     The plastic housing of such a large caliber firearm, on this account must be as thin-walled as possible and can only contain the least possible number of metal accessories. 
     Consideration could be given to increasing the wall thickness in the area of the magazine chamber while refraining from any further metal additions. However, such a measure would be problematic from the standpoint of the casting process. In addition, an area of transition between a larger wall thickness to a lesser wall thickness can form a zone subject to especially great stress, which can lead to a specific location of failure. 
     In practice, an effort is made to lengthen the walls of the magazine chamber toward the free magazine end, in order, on the one hand, to diminish the lever advantage of the magazine, and on the other hand, to stiffen the housing opening of the magazine entry. In the case of modem rapid-fire weapons, in their conventional construction, (magazine in front of the grip piece) or in the “bull pup” fashion, (magazine behind the grip piece) the housing opening for the trigger mechanism is in immediate proximity to the magazine chamber. Additionally, this opening weakens the magazine section, so that the lengthening of the magazine chamber by itself is not enough to correct the above outlined problem in structural strength. 
     A self-loading rifle is known, from U.S. Pat. No. 4,654,993 where an outer shell construction has been provided so that many parts, such as the trigger mechanism, exhibit a double housing. This rifle, however, possesses no magazine chamber but rather shows complementary rails on the back of the magazine, such as on a retaining yoke made of steel. 
     Further knowledge gained from the manufacture of traditional repeating or single load rifles with wooden stocks (see, e.g., U.S. Pat. No. 4,385,464), cannot be brought to bear on the issues presented here, since in those cases no housing is present. 
     SUMMARY OF THE INVENTION 
     The interested reader is referred to the appended claim for concise descriptions of the inventive combinations. Independent claim  1  recites, a housing system for use with a self-loading weapon. The housing system includes a weapon housing having at least one wall at least partially encompassing a magazine chamber; and an inner housing located at least partially within the at least one wall. The inner housing at least partially encompasses at least a portion of the magazine chamber. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view in partial cross-section of a weapon housing system constructed in accordance with the teachings of the present invention, showing a magazine, an inner housing, a rear end closure cap, and a back up plate. 
     FIG. 2 is an enlarged side view of the rear section of the housing system of FIG.  1 . 
     FIG. 3 is a cross-sectional view taken through section lines III—III of FIG.  2 . 
     All Figures show the same weapon housing system. The same reference numbers apply throughout for each element. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As used herein, expressions denoting position, such a “forward”, “behind”, “above”, “vertical” or the like, refer to a weapon held in a normal firing position wherein the bore axis (the centerline axis of the barrel) runs horizontally and the direction of shooting is “forward”. 
     The weapon housing system  10  shown in FIG. 1 can be used in a self-loading rifle of the so-called bull pup design. Such weapons lack the usually conventional back stock, which is at the most distant rear end of the weapon housing  1  in other weapons. The back stock could also have been either integral with or attachable to the forward part of the rifle, and possibly shortened in its construction. 
     Lacking this back stock, in the depicted example the weapon housing terminates directly with the closure cap  39  or the backup plate  41 . The magazine  45  seats itself then, as more or less a closure in front of the backup plate  41 . The gripping piece of the weapon (not shown) is located in front of the magazine  45 . 
     The weapon housing  1  exhibits a barrel sheathing  9  which extends itself forward. It also contains a guide strip  5  on its inner wall surface to align the breech (not shown). Adjacent to the movement path of the breech is an ejection window  3 , which can be closed off by a dust cover. As a rule, such a weapon exhibits two windows of this type. The oppositely lying ejection window is shown in FIG.  2 . In the normal arrangement, the ejection window  3  lies at the height of the cheek of the marksman. On this account safety measures must be upheld for the protection of the marksman from traumatic wounding. The safety measure in this example is that only the ejection window  3  on the opposite side of the weapon from the cheek of the marksman can be actuated. The normal or right handed marksman supports the weapon on the right shoulder and lays his right cheek against the left sidewall of the weapon housing  1 . In this situation, for the reasons given above, only the right side ejection window  3  (visible in FIG. 1) may be activated. The left handed marksman, in contrast, can only activate the left side ejection window as seen in FIG.  2 . 
     The construction of two, oppositely positioned ejection windows, leads to a structural weakening of the weapon housing  1 . The weapon housing  1 , could already be heavily subjected to stress at this location, because the magazine  45  is fastened under these ejection windows  3 . Many transverse forces of considerable size could arise from the magazine  45 . These forces can be introduced into the weapon housing  1 , for example, when the weapon falls inadvertently from an elevated position to the ground. These transverse forces can bring about damaging, twisting deformations in the weapon housing  1 , due to the zone weakened by the ejection windows  3 . 
     The weapon housing  1  further possesses an opening  7 , above the barrel sheathing  9 . This opening  7  opens to the front for receiving a loading lever apparatus which is securely bound to the breeching and movable therewith. The rear side of the weapon housing  1  is open. The closure cap  39 , which will be described in more detail below, is located in this opening. The backup plate  39 , on its rear side, is covered from the outside by the backup plate  41 . The backup plate  41  also serves as the shoulder piece, on the rim of which, there is attached one or, more preferably, two strap clasps  43 . 
     The stresses introduced by the strap clasps  43  are transferred to the tough yet resilient closure plate  39 , and via an appropriate fastening, are uniformly introduced into the weapon housing  1  through the peripheral structure of closure cap  39 . In case of damage, only the closure cap  39  must be exchanged, not the entire weapon housing system. 
     The upper holding strip  11  and the lower holding strip  13  are located underneath and parallel to the breeching guide strips  5 . The holding strips  11 ,  13  are constructed on the two side walls of the weapon housing  1 . These strips are preferably resilient and spring toward the interior. They serve for the guidance and retention of an inner housing  21 , described below. The strips  11 ,  13  also provide structural strength for the weapon housing  1 . 
     On its underside, the box shaped weapon housing has a magazine opening  15 . This opening  15  is bordered by one vertical forward wall  18  and two vertical sidewalls  17 . The lateral bordering walls  17  comprise part of the side walls of the weapon housing  1 . In front and above of the forward bordering wall  18 , a bore  19  penetrates each side wall of the weapon housing  1 . The bores  19  are aligned with one another to serve as a basis for the insertion of a fastening pin or a securing element (preferably a magazine securement or a bolting for a machine gun mounting). 
     The inner housing  21  is pushed into the weapon housing  1  from the back. To this end, each of the two sides of the inner housing  21  exhibits an upper counter holding strip  33  and a lower counter holding strip  35 . The strips  33 ,  35  are parallel. The cross-sections of the counter holding strips  33 ,  35 , are complementary to the cross sections of the above mentioned holding strips  11 ,  13 . The holding strips  11 ,  13  are so constructed that they slidingly engage with the complementary counter holding strips  33 ,  35  in such a manner that the inner housing  21  is securely fixed in its elevated position, as illustrated in FIG.  3 . 
     Thus, the lateral walls of the inner housing  21  together with the corresponding lateral walls  17  of the weapon housing  1  form a hollow box structural member, creating a highly bend and torque resistant construction (see FIG.  3 ). 
     The magazine chamber  23  is constructed in the inner housing  21  and is bordered at its forward extent by a vertical wall  27  and to the rear by a vertical back wall  25 . When the inner housing  1  is in place, the forward wall  27  abuts flat against the border wall  18  of the weapon housing  1 . The two bores  19   a  in the sidewalls of the inner housing  21  line up with the bores  19  of the weapon housing  1 , and serve for the passage of a service element for the breech block as well as for the securement of the inner housing  21  within the weapon housing  1 . Furthermore, the bores  47  in the side wall  17  of the weapon housing  1  and the bores  47   a  in the corresponding side walls of the inner housing  21  are aligned with each other, serving to accept pins or rivets, for effecting the fixation of the inner housing  21  in the weapon housing  1 . The force transmission between the inner housing  21  and the weapon housing  1  is carried out in the forward direction by the already mentioned arrangement between the front cross wall  18  of the outer housing  1  and the front cross wall  27  of the inner housing  21 . Force transmission between the inner housing  21  and the weapon housing  1  is carried out to the rear by the abutment of the inner housing  21  on the backup plate  41 . 
     The side walls of the inner housing  21  are lengthened front to back by forward and rear extension walls, respectively,  29  and  31 . The forward extension walls  29  (besides the discussed bores  19   a ) exhibit still more bores, which are intended for the connection of a trigger mechanism. A bottom plate, which binds the under edges of the two forward extension walls  29  together, reinforces the structure of the inner housing  21 . 
     The elements of the trigger mechanism (shown generally in FIG. 1) cooperate with the bottom plate and the forward cross wall  27  of the inner housing  21  to substantially reinforce the box-like structure of the forward extension walls  29 . The actuation of the trigger mechanism is done through a gripping piece or an attached device via a longitudinally movable rod or a finger. Such a device would be located under the barrel sheath  9 . Preferably, the trigger mechanism possesses no element which projects from the bottom, not even a downward projecting trigger. 
     The two rear extension walls  31  of the inner housing engage the back-up plate  41 . As may be inferred from FIG. 1, the groove/strip connections which are created by the complementary strip pairs  11 ,  33 , and  13 ,  35 , are considerably longer than the magazine  45 , as seen in the longitudinal direction of the weapon. This measure leads to an effective structural strengthening of the side walls  17  over the entire rear section of the weapon housing  1 . 
     If transverse forces are introduced from magazine  45  into the inner housing  21  and from this point on into the weapon housing  1 , no critical loads are reached. 
     The backup plate  41  is pushed into the back end of the weapon housing  1 , until it seats upon the rear exposed ends of the guide  5  and the strips  11  and  13 . A massive longitudinal bridging  51  is installed on this backup plate  41 . This bridging  51  is designed as a connecting rail that can be slidingly fitted into the upper edge structure  37  of the rear extension walls  31 . In the assembled weapon, the forward exposed end of the bridging  51  overrides the rear cross wall  25  of the inner housing  21  and lies from the back against the magazine lips. As a result, the longitudinal bridging  51  can pick up the forces which the magazine  45  projects to the rear. 
     The upper side of the bridging  51  is designed as a guide for the cartridge slider. The upper edges of the sidewalls of the magazine chamber  23  are somewhat extended upward and rolled to the outside, so that they additionally support the corresponding side walls of the weapon housing  1 . 
     The co-action between the weapon housing  1  and the inner housing  21  thus forms an especially strong and bend resistant magazine chamber. Some cross forces are primarily transferred into the inner housing  21  (which incidentally forms the actual magazine chamber  23 ), and are thereafter carefully distributed to the outer weapon housing  1 . Therefore, the strips provide for the introduction of force, while at the same time they reinforce the weapon housing  1 . They additionally aid in forming the cross pieces of the box structure, to which the sidewalls are extended. 
     Practically every element of the disclosed weapon housing system performs several functions so that, with few, thin-walled, largely or totally unreinforced plastic construction components, a surprisingly substantial, yet light weight housing has been created. 
     The depicted housing system can be constructed not only of plastic, but, with small modifications, also of sheet metal. As a result of its low weight and its high structural strength, this housing can be used for a rifle which fires high capacity cartridges (for example, a sharp shooting rifle for 0.50 Browning cartridges) at extended shooting distances. 
     From the foregoing, persons of ordinary skill in the art will appreciate that the disclosed weapon housing system  10  is comprised of at least two housings, with one housing encased within the other housing, thus establishing first, a weapon housing  1  and second an insertable inner housing  21  therewithin. The disclosed housing resists the stresses introduced by the magazine, while avoiding any significant increase in weight. 
     The weapon housing  1  is, of itself, well known. It is constructed of metal and/or plastic and includes at least a wall structure surrounding the magazine chamber  23 . 
     The inner housing  21  has a box-like structure which is open at the top and bottom. The inside of the inner housing  21  forms the magazine chamber  23 , or a part of the same. This box-like structure is within the weapon housing  1  and primarily accepts all stresses or, at least, the greater part thereof. With this construction, it becomes possible to affix this inner housing box to such points of the weapon housing  1 , which are already otherwise reinforced or provided with strengthening. The usual requirement to provide separate reinforcement and structural support for the magazine chamber  23  may be omitted. 
     Preferably, this box-like structure (i.e., the inner housing  21 ), can be removed from the weapon housing  1 . In the event that too great a load is applied to the magazine  45  and thereby transferred into the box-like structure, the box-like structure would preferably incur all the damage, and the weapon housing  1  would preferably incur none at all. The box-like structure can then be easily and inexpensively exchanged. 
     The disclosed weapon housing can be easily molded from plastic which permits a uniform housing wall thickness throughout. 
     It is possible that the inner housing  21  could cling close to the wall of the weapon housing  1  in the manner of a reinforcement layer. It is preferred, however, that a separating space, between the lateral walls of the weapon housing  1  and the walls of the inner housing  21  be maintained so that the space between the walls is compromised only at the fastening points between the inner housing  21  and the outer, weapon housing  1 . 
     The wall of the inner housing  21 , which borders the magazine chamber  23 , and the proximal lateral wall of the weapon housing  1  which is specifically distanced, together form the equivalent of a structural member. In spite of light weight, such an arrangement obtains substantially greater structural strength than would be the case if the inner housing wall and the weapon housing  1  laid directly against one another. This arrangement will also be free from deterioration, if the components which surround the inner housing  21  are made of corrosion resistant material such as plastic. 
     The inner housing  21  could be secured within the weapon housing  1  in many ways, including, but not limited to, by welding or by adhesive. Preferably, however, bar-like strips define complementary grooves located on the inner surface of the weapon housing  1  (on the lateral walls thereof) and on the outside surface of the inner housing  21 . These strips run in a longitudinal direction, so that the inner housing  21  can, preferably, be slidingly pushed into the main opening of the weapon housing  1  from the rear and be removed in the reverse manner. 
     The strips, which run in the longitudinal manner, extend themselves preferable over the entire length of the complete housing assembly. These members transmit the lateral bending forces arising at the free end of the magazine over the entire length of the strip/groove connection on the weapon housing  1 . Preferably, the protruding members are continuous rail strips and are designed as forward springing rails themselves. These strips strengthen the inner housing  21  as well as the weapon housing  1 . For the transmission of tension forces, the strip/groove combinations are also interlocked in such a manner that they transmit transverse forces in both directions. 
     The stressing of the weapon housing  1  is thus not carried out in an undefined manner over a large surface, but is strongly defined at the longitudinal strip/groove connections, which are best suited for accepting such a load. 
     Insofar as the already discussed spacing is present between the walls of the weapon housing  1  and the inner housing  21 , the strip/groove connections a form the narrow dimensions of the so-constructed box-like structural member within the weapon housing system  10 . The simple sliding of the inner housing  21  into the internal strips of the weapon housing wall enables the easy exchange of the inner housing  21 . If precautionary concerns for the removal of the breech dictate that the inner housing  21  must necessarily be removed, then there arises a further safety aspect, such as when a field disassembly of the weapon is necessary. Using a conventional rifle, the marksman is occasionally so misled as to put his loaded magazine into the disassembled weapon, so that it is not dirtied or lost. In such a case, the danger arises of an involuntary loading of the weapon. Using the present design, however, this danger is excluded, because, in a disassembled rifle, the magazine  45  cannot be securely locked into the weapon housing  1 . The inner housing  21  now forms the magazine chamber  23 , as well as it secures the retention of the magazine  45  in the weapon. 
     A preferred construction is the lengthening of the forward side walls (where weapons of bull pup design are concerned) or the rear side walls (where weapons of conventional design are concerned) of the inner housing  21 . Such lengthening forms among other advantages, a housing for the trigger mechanism. 
     In order to lessen the danger of dirt entering the trigger mechanism, it is customary not to allow the bearings of the individual axles or pins of the trigger mechanism to be set in the outer housing. The bearings are rather set in an individual trigger mechanism housing, which in turn is inset in the gripping stock. 
     In the disclosed device, since the inner housing  21  has been lengthened, then the projecting side walls of this inner housing  21  can perform the task of a trigger mechanism housing. The trigger mechanism is installed between the sidewalls, which at the same time provides additional structural strength for the inner housing  21 . Further, the assembly of the trigger mechanism is made much easier, since this is done externally from the weapon housing  1 . Therefore, the axles need not be additionally secured, because it is a part of the service of the housing wall. 
     If the inner housing  21  can be pushed into, as well as pulled out of, the weapon housing  1  from the back, then the trigger mechanism can likewise be installed and removed along with it, as long as this mechanism is not based on a trigger which projects from the bottom. In the latter case, the trigger mechanism would be contained in a component to be installed in the gripping piece, or, if necessary, in an additional apparatus yet to be added. 
     If the trigger mechanism possesses a transversely running safety shaft which is provided with an accessible outer knob, then this shaft or its knob can be placed in position later. In other words, it can be place in position following the insertion of the inner housing when the openings in the inner housing wall and the corresponding openings in the outer weapon housing wall are in alignment. The safety shaft, or pin, thus contributes to forming a reliable seating for the inner housing  21 , since it penetrates both the inner and outer housings  21 ,  1 . 
     Additionally, a forward detent can be provided, against which the inner housing  21  abuts and the inertial forces (in the case of a weapon falling upon the muzzle) are then absorbed by the inner housing  21 . 
     In order to provide for a similar detent to the rear, at least the side walls of the inner housing  21  are lengthened in that direction. At the rear, the inner housing wall abuts the end cap  39  of the weapon housing system  10  (in the case of the bull pup design) or impinges against the rear stock in conventional weapons. 
     The inner housing  21 , however, can also simultaneously form the end cap  39 , (i.e. the rear stock abutment). 
     Preferably, the rear extending side walls are designed to consolidate together in a trough-like manner, and to seat themselves. As explained above, this results in a force transmitting, strip/groove connection with the outer weapon housing  1 . In this way, a substantial increase is gained in the structural strength of the weapon housing system  10 , as well as in the rigidity of the magazine chamber opening. 
     All of the above described designs of the inner housing  21  can be manufactured of sheet steel or of sheet steel reinforced plastic. It is also possible to employ fiber reinforced or prepreg reinforced plastics. The preference, however, is for non-reinforced plastic. 
     The inner housing  21  of non-reinforced plastic is seated in a weapon housing, which, at least in the area of the magazine, is likewise comprised of non-reinforced plastic. When the non-reinforced plastic magazine  45  is inserted and the weapon is fired, there practically exists three plastic-box structures, one inside the other, which can accept the loadings of the impact of the recoil without further support. When this happens, the plastic in certain areas, is elastically deformable, so that the surfaces subjected to force, which, unstressed, lie against one another with longitudinal corrugations, are pressed together in mutual surface engagement, so that damaging concentrations of force are avoided. 
     Although certain examples of apparatus constructed in accordance with the teachings of the invention have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments falling within the scope of the appended claims either literally or under the doctrine of equivalents.