Patent Publication Number: US-2005115134-A1

Title: Shock absorber for a rifle

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      Non-provisional utility patent application claiming the benefit of Provisional Patent titled SHOCK ABSORBER FOR A RIFLE having U.S. application No. 60/517,185, and Filing Date of Nov. 04, 2003. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not applicable.  
     REFERENCE TO A MICROFICHE APPENDIX  
      Not applicable.  
      Certain rifles, such as shotguns, have a significant recoil or kick. When the trigger is pulled and the round of ammunition detonates, half of the kinetic energy released by the exploding gunpowder in the shell propels the bullet or shot forward through the barrel of the rifle and onward to the target. However, the other half of the kinetic energy goes in the opposite direction, rearward, and the rearward motion causes the force transfer to be absorbed largely by the user. For those who are unaccustomed to firing shotguns or who fire them a lot, the recoil can leave shoulders sore or bruised.  
      Accordingly, there is a need for a way to minimize the force transfer of the recoil of rifles such as shotguns. Several attempts have been made and some of these are the subjects of U.S. patents. See for example, U.S. Pat. No. 4,922,641, issued May 8, 1990, to Johnson, U.S. Pat. No. 4,551,937, issued on Nov. 12, 1985, to Seehase, and U.S. Pat. No. 5,375,360, issued Dec. 27, 1994, to Vatterott.  
      Nonetheless, there remains a need for a more effective way to absorb the kick, or force transfer of those rifles that have significant recoil.  
     SUMMARY OF THE INVENTION  
      According to its major aspects and briefly described, the present invention is a shock absorber for use with a rifle. The present shock absorber fits closely on the butt of the stock of a rifle and is made of foam. In addition to the impact-absorbing quality of the foam construction, the present device is shaped to trap a quantity of air inside air chambers, and release it through vent nozzles, thus using the compression bulge of the air and its delayed release as a way to prevent the immediate impact force transfer of momentum from stock to the shoulder of the user. By decreasing the force which the recoil transfers to the user, the impact is correspondingly reduced and, with it, the likelihood of injury or bruising. While no device can or will greatly arrest the rearward movement of the stock, the pain of recoil impact transfer can be significantly reduced and bruising negated.  
      The combination of foam construction, air-tapping chambers, and vent nozzle holes releasing said air are the features of the present invention. This combination allows the recoil kinetic energy to be managed and controlled so that it has less impact on the shoulder of the user.  
      The use of vent nozzle holes communicating from the chambers to the exterior of the device is another feature of the present invention. The vent nozzle holes prevent the pressure in the chamber from increasing sharply. As air pressure bulges the chamber construction during recoil, the vent nozzle holes allow compressed air to be released at a predetermined rate thus keeping the compressed air from transferring the recoil impact (force transfer) to the shoulder by the slow cushioning effect of air being vented as compression builds. The use of air venting is not a necessary by-product aiding springs, coils or other devices within cylinders; but a combination of air chambers, foam construction and nozzle release system working as one unit to produce a desired effect.  
      The one-piece moldable construction of the present device is another feature of it. By being configured in one simple piece, the present product is easier and cheaper to make. It is made of lightweight foam. Furthermore its shape allows the device to be fitted onto and easily removed from a rifle and transferred to another rifle if desired. It allows an owner of several rifles to own a set of the present shock absorbers at minimal expense, each one tuned to that particular user and rifle. While this one-piece construction is the preferred embodiment, the air chamber design will lend itself to a type construction that can be attached to a stock by screws or other fastening devices.  
      These and other features and their advantages will become readily apparent to those skilled in the art of rifle accessories from a careful reading of the following Detailed Description of Preferred Embodiments, accompanied by the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the drawings,  
       FIG. 1  shows a shock absorber, according to a preferred embodiment of the present invention, in use on a shotgun.  
       FIG. 2  shows a cross sectional, side view of the shock absorber of  FIG. 1 .  
       FIG. 3  shows an end view of the shock absorber of  FIG. 1 .  
       FIG. 4  is a front view of a shock absorber according to a preferred embodiment of the present invention.  
       FIG. 5  is a cross sectional, side view of the shock absorber of  FIG. 1  during maximum compression. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      The present invention is a shock absorber for use on a rifle, particularly shotguns and other rifles having a significant recoil kick.  
      The shock absorber according to the present invention and as illustrated in the accompanying drawings fits like a sleeve or cup over a portion of the stock of a rifle. The rifle of  FIG. 1 , generally indicated by the reference number  10  has a stock  12  with a shock absorber  14  carried thereon. Shock absorber  14  thus is positioned, when rifle  10  is held in the standard shoulder-firing position, between stock  12  and the shoulder of the user with the butt  16  of rifle  10  (see  FIG. 2 ) firmly seated in shock absorber  14 .  
      Shock absorber  14  is made entirely of foam rubber, either synthetic or natural foam rubber, and preferably of neoprene (closed cell flexible) or urethane foam. It may be made in colors such as camouflage colors, hunter orange or in basic black. Because it is resilient, it may be slipped onto and off stock  12  easily just as it may be slipped off of a mold in manufacture. Also, said material may incorporate within material U.V. retardant and or other chemicals to keep said material from breaking down with time or losing elasticity due to sunlight, heat or water.  
      A cross sectional detailed view reveals shock absorber  14  to have a much thicker base  20 , in the preferred embodiment than walls  22 . Base  20  has plural air-trapping chambers  24  formed in it, also visible in  FIG. 3 , and each air-trapping chamber communicates with the exterior of shock absorber  14  via vent nozzle holes to the outside air  26 , also visible in  FIG. 4 . Butt  16  is positioned to engage base  20  when shock absorber  14  is fully seated on stock  12 .  
      When rifle  10  is fired, the exterior surface  28  of base  20  is in position against the shoulder of the user.  
      When rifle  10  is fired, approximately half of the kinetic energy from the exploding round is directed rearward, resulting in movement of stock  12  rearward (to the right in  FIGS. 2 and 5 ). The movement of butt  16  toward the shoulder of the user compresses the foam of base  20 . It also compresses air  30  that is trapped in air-trapping chambers  24 . The trapped air is vented through vent nozzle holes  26 . However, vent nozzle holes  26  are sized or positioned to permit only the delayed (controlled or predetermined) venting of air to the outside of the device  30  and thereby act as shock absorbers, spreading the rearward movement over a longer or delayed time to reduce the impact by means of the foam construction bulging with compressed air and nozzle release of said air relieving said bulging therein greatly reducing the pain of force transfer to the shoulder of the user.  
      Initially the air-trapping chambers cannot be vented fast enough and pressure in air-trapping chambers  24  builds, thus limiting the further compression of the foam of base  20 . As recoil compressed air bulges the typical air-trapping chambers  24  the rearward movement of stock  12  increases pressure in the air-trapping chambers and is eventually matched by the rate at which air  30  is vented through vent nozzle holes  26 ; allowing progressive release of additional compression or bulging of the foam of base  20 . The rearward movement is slowed and allows the shock absorber to delay and absorb the recoil force over time rather than suddenly.  
      The recoil of a rifle is dependent on the type of rifle and to some degree, on the type of ammunition and or use of blow back recoil gases. Nonetheless, the present shock absorber can easily be engineered or tuned to the user and the rifle with modest rather than undue experimentation. Using neoprene or urethane foam for base  20  that is preferably one to two inches thick, with preferably three air-trapping chambers  24 , each one having one vent nozzle hole  26  of ⅛ th  inches or smaller in diameter, reasonable shock absorbing quality is obtained. Increasing the thickness of base  20  reduces recoil, and by also increasing the inside diameter of air-trapping chambers  24  while decreasing the size of vent nozzle holes  26  adds to the shock absorbing effect. In some cases the vent nozzle holes may be eliminated and type foam material constructed thin enough to allow bulging to compensate the recoil.  
      Wall  22  can be sized to grip stock  12  firmly, such as approximately ¼ to ½ inch in thickness with an interior dimension approximately equal to that of the exterior dimensions of stock  12 .  
      Those skilled in the art of firearm accessories will no doubt see that many substitutions and modifications can be made to the foregoing preferred embodiments without departing from the spirit and scope of the present invention, which is defined by the appended claims.