Abstract:
The present invention is a modular stock system for rifles. The system replaces the rifle&#39;s buffer tube with a modified one containing a mount for a constant cheek weld and a rail track for adjustment. A hind portion then mounts on the replacement buffer tube. The hind portion is interchangeable depending on the user&#39;s needs. Various configurations of the hind portion are discussed, including adjustable stocks, fixed stocks, and specialized stocks. The hind portion may be made even further modular by the addition of rail system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application claims priority based on earlier filed provisional application 60/300,646, filed on Jun. 25, 2001. 
     
    
     
       FIELD OF INVENTION  
         [0002]    The present invention relates to a rifle stock and more particularly related to a modular gunstock that provides a constant surface for a uniform cheek weld and the option of a variable length feature.  
         BACKGROUND OF THE INVENTION  
         [0003]    Adjustable gunstocks are known in the prior art. For example, U.S. Pat. No. 4,735,007 to Gal (1988); U.S. Pat. No. 4,327,626 to McQueen (1982); U.S. Pat. No. 3,442,042 to Gilbert (1967); U.S. Pat. No. 3,348,328 to Roy (1966); U.S. Pat. No. 3,267,601 to Roy (1964); 3,137,958 to Lewis, et al. (1962); U.S. Pat. No. 5,827,992 to Harris, et al. (1998) and U.S. Pat No. 2,900,877 to McClenahan, (1956) are all illustrative of the prior art.  
           [0004]    The current standard in automatic and semi-automatic rifles is to have a stock capable of receiving and covering a recoil absorption appendage, or “buffer tube”, shown in the &#39;992 and &#39;877 patents. The most popular of the available adjustable stocks follow in form to the &#39;328 patent, which is to say they use a spring loaded latch to bias a pin inside a provided adjustment hole. When a user wishes to adjust the stock, a simple compression of the spring/latch assembly is all that is required to release the pin and, therefore, adjust the stock. The &#39;626 patent operates with a tooth-and-groove assembly which, otherwise, follows the same principles. In both cases, compression of the spring is necessary for adjustment in both directions along any length beyond the proximate hole/groove. All of the adjustable stocks may have their butt portion removed, though are not designed to have such a feature repeatedly used, much less have additional stock modules to exchange. In those cases where the stock moves longitudinally along the weapon, with no other motion relative to the weapon, the user must make some sacrifice as to one, if not both, of two features. The user either loses constant and uniform cheek weld to the weapon or stock stability. The lack of uniform cheek weld can interfere with comfortable and precise use of the weapon. Stock stability can also interfere with precise weapon use.  
           [0005]    While the aforementioned insertions accomplish their individual objectives, they do not describe a truly modular stock, namely a stock where the butt portion is designed to be changed at the whim or need of the user. Likewise, they do not describe a stock that utilizes a cam/tension lock that enables the user to have not only a controlled extension, but also an unrestricted and silent compression and extension of the stock. None of the disclosed stocks have an adjustable preset lock to use in conjunction with an unrestricted adjustment. Finally, none of the disclosed stocks present a surface for a constant cheek weld while simultaneously having a sturdy, longitudal adjustment capable stock, much less a uniform cheek weld with different stock types. In this respect, the gunstock according to the present invention departs substantially from the usual designs in the prior art. In doing so, this invention provides a modular gunstock allowing for a uniform and identical cheek weld for different stock modules, even while simultaneously adjusting the stock length of an adjustable stock.  
         SUMMARY OF THE INVENTION  
         [0006]    In view of the foregoing disadvantages inherent in the known types of gunstocks, this invention provides an improved gunstock. As such, the present invention&#39;s general purpose is to provide a new and improved modular gunstock that will have multiple functionality, dependent upon chosen stock modules. The invention will provide simultaneous adjustment of the stock while providing a sturdy, uniform cheek weld on the stock when used with an adjustable module. The invention will also provide an identical cheek weld surface with a sturdy stock if a fixed stock is used.  
           [0007]    To provide the improved features, the gunstock comprises both a fore and butt portion. The fore portion consists of a buffer tube attachable to the weapon&#39;s receiver and a cheek plate extension essentially parallel to the buffer tube. Located on the underside of the buffer tube is a rail track. The rear portion consists of a receiving cylinder of sufficient length and width to receive the buffer tube of the fore portion. Located on the lower rim of the cylinder is the at compression latching mechanism designed to interface with the rail track. Rearward of the receiving cylinder is the stock butt and any other accessories as required by the user. In the preferred embodiment, the cheek plate is fused to the buffer tube, presenting a wider rest for a user&#39;s cheek, and the rear portion comprises a receiving cradle, or semi-cylinder, which interfaces along a pair of attachment grooves located on either side of the buffer tube, having a distal relation with the cheek plate  
           [0008]    The more important features of the invention have thus been outlined in order that the more detailed description that follows may be better understood and in order that the present contribution to the art may better be appreciated. Additional features of tile invention will be described hereinafter and will form the subject matter of the claims that follow.  
           [0009]    Many objects of this invention will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.  
           [0010]    Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.  
           [0011]    As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    [0012]FIG. 1 is a side elevation of a rifle with the modified buffer tube according to the present invention.  
         [0013]    [0013]FIG. 1 a  is the rifle of FIG. 1 with an adjustable stock attachment.  
         [0014]    [0014]FIG. 1 b  is the rifle of FIG. 1 with a fixed stock attachment.  
         [0015]    [0015]FIG. 1 c  is the rifle of FIG. 1 with a “shorty” fixed stock attachment  
         [0016]    [0016]FIG. 2 is a bottom plan view of the modified buffer tube module.  
         [0017]    [0017]FIG. 3 is a side elevation of the modified buffer tube module.  
         [0018]    [0018]FIG. 4 is a cross section of the buffer tube module of FIG. 3 taken at line  4 .  
         [0019]    [0019]FIG. 5 is a three staged side elevation showing the use of the adjustable stock embodiment.  
         [0020]    [0020]FIG. 6 is a side plan view of an adjustable stock module.  
         [0021]    [0021]FIG. 7 is cross-section view of the module of FIG. 6, taken along line  7 .  
         [0022]    [0022]FIG. 8 is a side elevation depicting the use of the current standard adjustable stock.  
         [0023]    [0023]FIG. 9 is a side elevation depicting the use of the present invention with an adjustable stock module.  
         [0024]    [0024]FIGS. 10 a  through  10   f  depict side elevations of suggested stock options.  
         [0025]    [0025]FIGS. 11 a  through  11   c  are side elevations of a specialized stock option that has further modularity.  
         [0026]    [0026]FIG. 12 is a cross-section view of the latching mechanism.  
         [0027]    [0027]FIGS. 13 a - g  display a blown-apart view of the latching mechanism.  
         [0028]    [0028]FIG. 14 is a three-staged partial cross section of the modular stock of FIG. 5.  
         [0029]    [0029]FIG. 15 is a bottom plan view of the buffer tube module and associated preset system.  
         [0030]    [0030]FIG. 16 is a cross section view of the buffer tube module of FIG. 15, with the preset clip removed, taken along line  16 .  
         [0031]    [0031]FIG. 17 is two close up views of the preset tooth. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    With reference now to the drawings, the preferred embodiment of the modular gunstock will be explained. With reference to FIGS. 1, 1 a,    1   b,    1   c,  the gunstock is composed of a modified buffer tube module  2  and a stock module  12 . Buffer tube  2  fits on rifle  1  by replacing the existing buffer tube of the rifle with the buffer tube module  2 . In addition, referencing FIGS. 3 and 4, rail track  8 , with individual lateral grooves  6  and single transverse groove  7 , is disposed towards the ground and cheek mount  10  is disposed upwards and is generally parallel to buffer tube  4 . Two longitudinal tracks  9  are disposed slightly underneath cheek plate  10  providing attachment tracks for stock module  12 . Ideally, the cheek plate  10  is fused onto the buffer tube  2 . However, in alternative embodiments, enough space can be left between buffer tube  4  and cheek plate  10  to allow for unhindered motion of a cylindrical stock module. Tooth interfaces  5  are disposed underneath the longitudinal tracks  9 .  
         [0033]    Referring to FIGS. 6 and 7, stock module  12  has a receiving cradle  14  that fits over buffer tube module  2 . Two attachment rails  18  are disposed at the upper two edges of the cradle  14 . Behind receiving cradle  14  is the butt  16  of the stock. Butt  16  may be modified in various configurations, depending on the reeds of the user, shown in FIGS. 10 a - e  and  11   a - c.  In the adjustable embodiment shown. In FIG. 1 a,  latching mechanism  20  interfaces with rail track  8  via a double cusped tooth  28  and cam mechanism, shown in detail in FIGS. 12, 13 and  14 . Latch switch  24  has three settings, shown FIGS. 5 and 14, which activate compression mechanism  26  to bias tooth  28  against tooth interface  5 . As tooth  28  is further biased against interface  5 , stock module  12  is locked into relative position against the buffer tube module  2 . Tooth  28  has a forwards disposed angle  30 , which, at the proper setting, allows for extension of the stock while prohibiting compression. In the locked setting, cam anchor  32  (shown in FIGS. 12 and 13) is biased into the rail track  8  in one of the lateral grooves  6 , while tooth  28  is locked into a non-movable interface with tooth interface  5 . This construction allows a three point locking system that gives more security and stability than the prior art single point locking systems. In FIGS. 5 and 14,  22   a  depicts a locked setting;  22   b  depicts an extension only setting; and  22   c  depicts a free motion setting. In all embodiments, rails  18  are slid through tracks  9  for proper guidance and hold. In fixed stock configurations, such as FIGS. 1 b  and  1   c,  a latching mechanism may be employed or a pinning system may be utilized  
         [0034]    [0034]FIG. 8 shows the prior art adjustable stock configuration. Notice that user  80  places cheek  82  against the weapon  84 . Cheek  82  is positioned against the juncture of the fore  86  and hind  88  portions of the stock. This not only causes discomfort but also interferes with the use of the weapon. FIG. 9 shows use of the present invention. User&#39;s cheek  82  is now placed against cheek plate  10 , eliminating discomfort and minimizing disruption caused by placement at the juncture as in the prior art.  
         [0035]    In keeping with the modularity of the present invention, numerous configurations of hind portion  12  may be used for various uses. All of which are made to interface with the replacement buffer tube  4 . Shown in FIGS. 10 a - 10   e  are five such configurations for adjustable stocks. FIG. 10 a  depicts a carbine stock;  10   b  a foldable stock;  10   c  an adjustable stock with a battery pack. FIGS. 10 d  and  10   e  depict mounting systems for ammunition for additional mounted weapon attachments. FIGS. 11 a - 11   c  displays a further modular fixed stock. Hind portion  112  may be extended away from stock base  110  as needed for spacer  114 . Spacer  114  may be a battery pack, a simple extension or anything a user desires. An additional side mounting rail systems may also be added to any stock module.  
         [0036]    The present invention utilizes a compression, or “cam”, latch with adjustable modules, shown in better detail in FIGS. 12, 13 and  14 . It incorporates a latch body  22 , divided in two halves, a safety latch  24  attached to a spring mount  25  with a safety tooth  27 , and a bicuspid latch tooth  28  and an associated cam mechanism  26 . Latch  20  is axially mounted about two mounting holes  34 , one in each half  22 , in a manner to interface with rail track  8  and tooth interfaces  5 , shown in FIGS. 3 and 4. Latch  20  has three settings. Latch body  22  is pulled backwards to disengage latch tooth  28  from tooth interfaces  5 . This setting allows free adjustment, forwards and backwards, of the module. Cam mechanism  26  operates to bias latch tooth  28  into a middle, ratcheting position. The latch tooth has a forwards-facing angle  30 , which allows latch tooth  28  to catch the rail track if the stock module is pushed forwards, but disengages from tooth interfaces  5  for backwards extension. The final position is a locked position which forces latch tooth  28  into an almost vertical position. Cam anchor  32  is also forced into rail track groove  6 . Safety latch  24  is forced to interface with the stock module with its safety tooth  27  by spring mount  25 . The interface prevents latch body  22  from being compressed accidentally. Spring mount  25  is embedded into latch body  22  in such a manner that when safety latch  24  is mounted upon it, safety latch  24  is flush with latch body  22 .  
         [0037]    In an alternate embodiment, shown in FIGS. 15, 16, and  17 , a catch tooth  50  is disposed above the latching mechanism to interface with transverse channel  57 . Catch tooth  50  is mounted upon catch base  52 , forming a shape reminiscent of a capital “T”, and is biased by spring  54  into a central position. Stop bar  56  is a clip insertable into the lateral grooves  55  of transverse channel  57 . Stop bar  56  has a groove  59  corresponding with transverse channel  57  except that groove  59  is almost dissected by projection  58 , leaving enough room for tooth  50  to pass through if biased to one side. In so doing, a preset function is added to this embodiment. A user simply inserts a stop bar at a desired length. When extending the stock module, tooth  50  will be blocked by projection  58 , thus arresting extension of the stock module. To pass the stop bar, the user presses stop base  52  to one side, allowing tooth  50  to pass. Spring  54  then returns tooth  50  to a central position when pressure is released. A second stop bar, possibly with projection  56  facing a different direction, may be added for further security. In addition, the back of the transverse groove  57  may be fashioned with such a projection to prevent the stock module from accidentally being pulled off the buffer tube module.  
         [0038]    Although the present invention has been described with reference to preferred embodiments, numerous modifications and variations can be made and still the result will come within the scope of the invention. No limitation with respect to the specific embodiments disclosed herein is intended or should be inferred.