Abstract:
A cartridge magazine for firearms has an elongated channel to receive a plurality of cartridges. The cartridge magazine has a box forming a housing of the cartridge magazine, a spring operated follower for pressing the cartridges in the magazine to an upper position. In this position, the topmost cartridge is ready for feeding into a chamber of the firearm and in this position the topmost cartridge rests against a pair of retaining lips. The lips remain in a first position when the topmost cartridge is in the upper position and the lips are operatively displaceable to a second position wider than the first position.

Description:
TECHNICAL FIELD OF THE INVENTION 
       [0001]    This invention relates to a detachable single column also known as single row cartridge magazine of a firearm. 
       BACKGROUND OF THE INVENTION 
       [0002]    A single column cartridge magazine is a well-known type of cartridge magazine. There are several benefits for this particular cartridge magazine type. It is simple and reliable. The cartridge to be fed into the chamber is initially on the same vertical plane as the chamber, which means that the cartridge does not need to move sideways while feeding into the chamber. The single column magazine is also generally easier and cheaper to manufacture than a double column magazine. The width of a firearm having a double column magazine is greater than a firearm with a single column magazine. In some cases this width is a disadvantage, especially if a narrow receiver and stock is expected. Also the receiver construction is easier to design and manufacture when there is not a wide opening needed for cartridges to be loaded from the double column cartridge magazine. In those cases where extreme strength of the receiver is requested, this single column cartridge magazine allows more material on the lower part of the receiver and thus stiffer construction. 
         [0003]    A single column cartridge magazine has a smaller cartridge capacity than a double column cartridge magazine having the same depth. In addition to this feature, a single column cartridge magazine is not preferred in all circumstances. Some users prefer to insert new cartridges to the magazine via ejection opening of the receiver when the bolt is in the open position. In a traditional version of a single column cartridge magazine this is not possible. The user must detach the magazine and load it while it is separated from the firearm. To load the cartridge magazine the user needs to press the rear of the cartridge beneath the retaining lips and push the cartridge rearwards. This is because the retaining lips of the cartridge magazine need to be designed such that a mutual distance between the retaining lips is smaller than the diameter of the cartridge case in order to function correctly. In a single column cartridge magazine the retaining lips of the cartridge magazine set the height of the topmost cartridge in relation to the frame of the cartridge magazine and the receiver of the firearm. When the bolt is moved to the closed position, the face of the bolt takes the topmost cartridge from the cartridge magazine and loads this cartridge into the chamber. So basically to remove the topmost cartridge from the cartridge magazine requires horizontal movement in a feeding direction to be released under the down-pressing contact of the retaining lips. 
         [0004]    The single column cartridge magazine sets the cartridges in one column having a virtual vertical centerline, which centerline is also the centreline of the chamber and the barrel. Thus, there is no need for movement of a cartridge sideways during the loading. The cartridge need only be moved vertically from the position defined by the cartridge magazines retaining lips to the chamber. This elevation is normally done by a conically shaped feeding ramp, which is located at the rear end of the chamber. When the topmost cartridge is pushed to the chamber by the bolt, the first contacting end of the cartridge is the bullet and it slides along the feeding ramp and guides the cartridge into the chamber. 
       OBJECT OF THE INVENTION 
       [0005]    It is an object of the present invention to provide an improved single column cartridge magazine. 
         [0006]    It is still another object of the present invention to provide an improved single column cartridge magazine which can also be loaded when attached to the firearm. 
         [0007]    It is still another object of the present invention to provide an improved single column cartridge magazine which is capable of guiding the topmost cartridge into the chamber. 
         [0008]    It is still another object of the present invention to provide an improved single column cartridge magazine which cartridge is loaded into the chamber by a guiding portion of the cartridge magazine in such a way that the frusto-conical shoulder portion of the cartridge is used for guiding purposes. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention overcomes the limitations of the prior art by providing an improved cartridge magazine for firearms, the cartridge magazine having an elongated channel to receive a plurality of cartridges in a single column, the cartridge magazine comprising:
       a box for forming a housing of the cartridge magazine,   a spring operated follower for pressing a plurality of cartridges in the cartridge magazine to an upper position   in the upper position the topmost cartridge is ready for feeding into a chamber of the firearm and in the upper position the topmost cartridge rests against a pair of retaining lips,       
 
         [0013]    wherein 
         [0014]    the retaining lips remain in a first position when the topmost cartridge is in the upper position, and the retaining lips are operatively displaceable to a second position wider than the first position. 
         [0015]    Thus this single column cartridge magazine comprises stiff but still bendable retaining lips. The retaining lips are formed from a stiff and shape permanent material such as steel, aluminum or other suitable material. The bendability is obtained by a flexible element of the cartridge magazine box. This flexible element may be a slit or a pair of slits of a certain length at the rear wall of the cartridge magazine. Preferred material of the cartridge magazine box for this purpose is suitable polymer or fiber reinforced polymer. 
         [0016]    An improved single column cartridge magazine of the present invention optionally also comprises a cartridge guide. This cartridge guide has several functions. One main function of the cartridge guide is to guide the topmost cartridge into the chamber. There are beveled edges on the upper part of the cartridge guide so that the frusto-conical shoulder portion of the cartridge touches the beveled edge when the cartridge is pressed forward by the bolt and the cartridge is guided by these two elements into the chamber. This means that the bullet is not used as a guiding surface or element during the loading movement as it is used in conventional designs. This different guiding principle makes a significant difference. If the bullet is for some reason twisted from its original position during the loading, it may disturb the highly important accuracy of the firearm. Here the term twisted means that the center axis of the cartridge case and the bullet are no longer the same, i.e. coaxial. The cartridge guide together with the stiff but bendable retaining lips ensure a precise positioning of the topmost cartridge in its initial position at the cartridge magazine and through the feeding action until the rear end of the cartridge case loses contact with the retaining lips and beveled edge of the cartridge guide. Also, all the subsequent cartridges in the cartridge magazine remain in one precise position during the loading and also during the recoil. This precise positioning is one of the key elements in reliable cartridge feeding action. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    The nature of the present invention, as well as other objects and advantages thereof, will become more readily apparent from the following description of the disclosed preferred embodiment as shown in the drawings, in which: 
           [0018]      FIGS. 1A and 1B  presents a general overview of the cartridge magazine of present invention,  FIG. 1A  is a side-front view and  FIG. 1B  is a side-rear view, 
           [0019]      FIG. 2  presents a firearm suitable for applying the present invention, 
           [0020]      FIG. 3  presents a cross-section of the firearm of  FIG. 2  at cross-section A-A, when a topmost cartridge is between the retaining lips, 
           [0021]      FIG. 4  presents a cross-section of the firearm of  FIG. 2  at cross-section A-A, when a topmost cartridge is in a stationary upper position, 
           [0022]      FIG. 5  presents a side cross-section of the cartridge magazine of present invention, 
           [0023]      FIG. 6  presents a top view of the cartridge magazine of present invention, 
           [0024]      FIG. 7  is a topview of five magazines of two different cartridge magazine box sizes with different cartridge guides to cover five different common cartridges for firearms. 
       
    
    
     DETAILED DESCRIPTION 
       [0025]      FIGS. 1A and 1B  presents a general overview of the cartridge magazine  1  of the present invention. In this figure it is presented the preferred embodiment of the invention. The main elements of the cartridge magazine  1  concerning the invention are a cartridge magazine box  12  having a front wall  124 , two side walls  123 , a rear wall  122 , two retaining lips  10 , a cartridge guide  15  and its beveled edges  151 . The flexible element  121  is obtained by two slits on the rear wall  122  of the box  12 . The box is made of one piece cast plastic and its side walls have ribs  120  to stiffen the construction. Therefore the retaining lips  10  made of steel maintain their original shape but bend just enough to let the cartridge (not shown) be loaded in. A follower  13  is loaded by a spring  14  (not shown in this figure). 
         [0026]      FIG. 2  presents a suitable firearm  3  for applying the present invention. The firearm  3  may comprise a receiver  31  having an ejection opening  311 . For the present invention this ejection opening  311  has at least two purposes: to enable the user to load the cartridge magazine  1  while the cartridge magazine  1  is operatively attached to the firearm  3  and as a second purpose to enable ejection of spent cartridge cases  20  after firing.  FIG. 2  also shows a bolt  33  in its open position where the bolt is ready to push a new cartridge to the chamber  36 . Other main parts are a barrel  37  and a stock  39 . The section markings A-A presents the intersection disclosed in more detail with  FIG. 3  and  FIG. 4 . A cartridge magazine  1  and a magazine opening  391  are not particularly shown on this  FIG. 2 . 
         [0027]      FIG. 3  presents a cartridge magazine according to the present invention. In this figure it is presented a situation where a user of the firearm  3  is loading a cartridge  2  to the cartridge magazine  1  via the ejection opening  311  of the receiver  31 . Said loading or inserting direction/force is illustrated by an arrow L. When the loading force L is applied, the cartridge presses the retaining lips  10  apart from their initial first position X (shown in  FIG. 4 ) to a second position Y. Thus the retaining lips  10  are operatively displaceable from said first position X to said second position Y when a cartridge  2  is being inserted to the cartridge magazine  1  by a user of the firearm  3  while the cartridge magazine  1  is operatively attached to the firearm  3 . The cartridge magazine is connected to the firearm  3  through the opening  391  in the stock  39 . In said second position Y the distance y 1  between the retaining lips  10  is equal to or greater than the diameter of the cartridge case  20 . Here the distance y 1  means a minimum distance between the corresponding retaining lips  10 . The functionality that the side walls  123  are operatively displaceable is illustrated by arrows F. 
         [0028]      FIG. 4  presents a stationary situation after the loading phase of  FIG. 3 , where in  FIG. 4  the topmost cartridge  2  is in an upper position of the cartridge magazine  1 . The cartridge  2  has passed the retaining lips  10  and the retaining lips  10  have reversed F to their initial first position X. In said first position X the distance x 1  between the retaining lips  10  is less than the diameter of the cartridge case  20 . Here the distance x 1  means a minimum distance between the corresponding retaining lips  10 . The preferred embodiment of this feature is inherent of the plasticity of the cartridge magazine box  12  and its side walls  123  combined together with the flexible element  121  (not shown). The dimensions of the ribs  123 , the length of the slit  121  and material properties of the box  12  are designed in this preferred embodiment to set a bending resistance of the retaining lips to a comfortable level so that the spring  14  (shown in  FIG. 5 ) is not able to press the topmost cartridge  2  out of the cartridge magazine and still the user does not find the resistance of inserting cartridges  2  to the cartridge magazine  1  too uncomfortable. Preferably the cartridge magazine box  12  for this purpose is a one piece plastic cast. 
         [0029]      FIG. 5  presents a side cross-section of the cartridge magazine  1  of present invention. The main parts of the cartridge magazine are a retaining lips  10 , a box  12  and its rear wall  122  and front wall  124 , a follower  13 , a spring  14  for pushing the follower and cartridges (not shown) to a upper position, a cartridge guide  15  and its beveled edges  151 . 
         [0030]      FIG. 6  present a top view of the cartridge magazine  1  of present invention. The parts shown in this  FIG. 6  are: retaining lips  10 , follower  13 , cartridge guide  15  and its beveled edges  151 . 
         [0031]      FIG. 7  is a topview of five cartridge magazines of two different cartridge magazine box sizes with different cartridge guides to cover five different common cartridges for firearms. From the economical point of view this is very interesting. It enables a firearm manufacturer to design or select two different cartridge magazine box sizes which covers the whole assortment of commercially interesting and top selling cartridges. 
         [0032]    However, the interest is not only from the economical side, but also this brings a clear technical advantage over the common way of guiding a cartridge  2  to the chamber  36  of the firearm  3 . According to one embodiment of the present invention, the retaining lips  10  are operatively displaceable from said first position X to said second position Y when a cartridge  2  is loaded from the cartridge magazine to the chamber  36  by the bolt  33  of the firearm  3  while the cartridge magazine  1  is operatively attached to the firearm  3 . This enables an improved way to guide a cartridge  2  to the chamber  36 . Indeed, the cartridge magazine may further comprise a cartridge guide  15  for steering the cartridge  2  from the cartridge magazine  1  to the chamber  36 . For this purpose the cartridge guide  15  may have beveled edges  151  to form a mating surface to be in guiding contact with a frusto-conical shoulder portion  201  of the cartridge case  20  and therefore the bullet  25  is not used as a guiding surface. This combination of operatively displaceable retaining lips  10  and cartridge guide  15  results in a very smooth and reliable feeding action where the bolt  33  is gently pushing the cartridge  2  to the chamber  36 . 
         [0033]      FIG. 7  shows the idea that the cartridge guide  15  is an interchangeable part of the cartridge magazine. With slight modifications in dimensions, the cartridge guide  15  is adapted to fit the dimensions of the cartridge  2 . When a cartridge magazine is used for hunting purposes, the user appreciates silent equipment. When the cartridge guide  15  is adapted to minimize the loose space between the cartridge  2  and the cartridge magazine box  12 , it reduces the possible noise of cartridges  2  clicking toward the cartridge magazine box  12  to a minimum. It also helps in the objective of the invention to build a very reliable feeding action to the firearm, such as a bolt action rifle, because the cartridges  2  in the cartridge magazine are located in constant positions. In one of the preferred embodiments here, the cartridge guide  15  is adapted to offset the cartridges  2  in the cartridge magazine  1  to a position where the offset in a axial direction of the cartridges  2  is less than ⅛″ (approx. 3 mm). 
         [0034]    One further embodiment of the invention is the material selection for the cartridge guide  15 . It is an advantage, if the cartridge case  20  does not “stick” to the cartridge guide  15 . Therefore the friction between these two elements should be as low as possible. The inventor has found, that the preferred embodiment is a cartridge guide  15  made from a plastic material having a low friction coefficient, i.e. less than 0.3 with brass. As it is well-known in this field of technology, the majority of cartridge cases are manufactured of brass. 
       INDUSTRIAL APPLICABILITY 
       [0035]    This invention is applicable to cartridge magazines to be sold together with a firearm such as rifles, bolt action or semi-automatic rifles, pistols, other firearms, etc. or as a after-market or sparepart cartridge magazine. Since the best mode of carrying out the invention is adapted for cartridges with frusto-conical shoulder portion, the majority of applications lie in the field of centerfire rifles. 
         [0036]    It will be understood that the foregoing relates only to a disclosed preferred embodiment(s) of the present invention, and that numerous alterations and modifications may be made therein without departing from the spirit and the scope of the invention as defined in the following claims. 
       LIST OF REFERENCE NUMBERS IN FIGURES  
       [0037]      1  cartridge magazine 
         [0038]      10  retaining lips 
         [0039]    X first position of retaining lips 
         [0040]    x 1  distance between the retaining lips  10  in a first position X 
         [0041]    Y second position of retaining lips 
         [0042]    y 1  distance between the retaining lips  10  in a second position Y 
         [0043]    L loading or inserting force/direction 
         [0044]      12  cartridge magazine box 
         [0045]      120  ribs 
         [0046]      121  flexible element, slit 
         [0047]      122  rear wall 
         [0048]      123  side wall 
         [0049]    F flexibility of the side walls  123   
         [0050]      124  front wall 
         [0051]      13  follower 
         [0052]      14  spring 
         [0053]      15  cartridge guide 
         [0054]      151  beveled edges 
         [0055]      2  cartridge 
         [0056]      20  cartridge case 
         [0057]      201  frusto-conical shoulder portion 
         [0058]      25  bullet 
         [0059]      3  firearm 
         [0060]      31  receiver 
         [0061]      311  ejection opening of the receiver 
         [0062]      33  bolt 
         [0063]      36  chamber 
         [0064]      37  barrel 
         [0065]      39  stock 
         [0066]      391  magazine opening