Abstract:
The present invention relates to the field of rifles. The invention further relates to ejection ports for AR-15 and M-16 rifles. The invention even further relates to a safety and equipment protection a portion of an ejection port door that is impacted repetitively on its bumper. The present invention even further relates to a cover that removeably snaps upon the bumper of the ejection port door.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of rifles. The invention further relates to ejection ports for AR-15 and M-16 rifles. The invention even further relates to a safety and equipment protection a portion of an ejection port door that is impacted repetitively on its bumper. The present invention even further relates to a cover that removeably snaps upon the bumper of the ejection port door. 
     2. Description of Related Art 
     AR-15, AR-10 and M-15 rifles have been utilized for decades and are popular with civilians, law enforcement and military shooters around the world for the firearms&#39; accuracy and modularity. In general such rifles are self-loading and capable of performing certain function without user assistance. When depressing the trigger, the rifle should fire a single cartridge, then extract the empty case from the chamber, eject the empty case, load another cartridge into the chamber from the magazine. 
     Two most common systems of are a direct impingement and indirect or gas impingement system. The direct impingement system reflects the original design by Stoner, as reflected in U.S. Pat. No. 2,951,424, for a gas operated bolt and carrier system, incorporated here by reference. Generally speaking, it routes exhaust gases from the barrel back through the rifle to move the bolt carrier to a retracted position, through the return tube to the bolt carrier and out the ejection port of the receiver. 
     With the more modern gas impingement system, as a projectile bullet fires it moves past a gas port located in the barrel of the firearm to convey gas into a port and through a gas tube and gas key. The high pressure gas then causes a bolt carrier to expand rearward and towards the butt of the firearm, as a result the bolt is unlocked from the barrel extension and carries rearward along with the bolt carrier. The bolt&#39;s rearward motion extracts an empty cartridge from the chamber. As the case clears the extension of the barrel, bolt&#39;s spring loaded ejector forces it from the ejection port in the side of the receiver. 
     With both systems, the ejection port often has an ejection port door that covers the ejection port to prevent debris from entering the receiver and interfering with firing components. The ejection port door automatically opens during the firing of the rifle, and is spring loaded to return to a closed position against the receiver after the empty case ejects from the port. The port door specifically contains a tab with a seating surface that forcefully returns against the door interface of the lower portion of the receiver. The seating surface is a small percentage of the entire surface area of the ejection port door. The forceful return of the ejection port door as created by the rearward action of the bolt creates a number of problems for the rifle, the operator and potentially others in the operator&#39;s party. 
     First, the forceful return of the ejection port door against the receiver is a highly impactful that degrades both the tab of the ejection port door as well as the receiver. As the gun undergoes repeated discharges, the tab and receiver will inevitably wear down to the point where they no longer interface correctly, causing operational failures much as misfiring, jamming, due to either an ejection port door that is sticks at the open/close position, or is unable to seat at either position. The operator must then attempt to replace the ejection port door and/or the portions of the receiver that meets the door. This is an involved, time and cost-consuming maintenance. 
     Second, the forceful return of the ejection port door against the receiver causes a loud report, as the door bumper and receiver are often made with metallic such as steel, aluminum or alloys thereof, or high-impact plastics. A loud report from the firearm can be detrimental from an array of tactical, environmental, and safety standpoints. It alerts others to the location of the operator and gives away the element of surprise, to for instance, a target of an ongoing tactical mission. A loud report may cause hearing injury, especially over time with repeated exposure. Such high-pitched pings may prevent the operator from collecting other, important auditory feedback from his or her environment. Finally, the loud report creates noise pollution that negatively impacts others nearby. 
     There is a need for a solution that reduces such loud reports from the use of such rifles. There is a need for better tactical outcomes when using rifles having ejection port doors. There exists a great need to reduce the noise pollution from the use of these rifles that is generated from the door striking the receiver. There further exists a need to prevent wear on parts of a rifle that are difficult to replace and maintain, where mechanical interactions between metal parts quickly degrade them. 
     SUMMARY OF THE INVENTION 
     In one embodiment of the invention there is provided a cover that snaps upon a bumper of an ejection port door of a rifle, the cover protecting the bumper against traumatic contact with a receiver portion of the rifle, the cover comprising an interface surface and a recess side, the recess side having a recess with an interior perimeter defined by a first wall, a second wall, a third wall, and a fourth wall, the first wall and third wall having a parallel relationship to one another, the second and fourth wall having a parallel relationship to one another, the first wall and the third wall each having a height, the height of the first wall being less than the height of the third wall, the height of the first wall and third wall representing a distance between the recess side and a recess surface, the recess surface having a base surface and a diagonal surface, the base surface extending from the first wall to the diagonal surface, the diagonal surface extending from the base surface to the third wall, the height of the third wall being less than the height of the first wall, the second wall and the fourth wall being perpendicular to the first and third walls, an exterior perimeter of the recess side, at least a portion of the exterior perimeter having a reduced margin, wherein the reduced margin that creates a gap between the cover and the ejection port door so that an operator of the rifle may utilize the gap to manually remove the cover from the bumper. 
     In another embodiment of the invention is provided a cover to place securely upon a bumper of an ejection port door of a rifle, the cover having an interface surface, a recess side having an interior perimeter and an exterior perimeter, the interior perimeter defining a recess having an approximately similar spatial volume and dimension as the bumper, at least a portion of the exterior perimeter having a reduced margin, wherein the reduced margin creates a gap between the cover and the ejection port door so that an operator of the rifle may access and utilize the gap to manually remove the cover from the bumper. 
     In still another embodiment of the invention is provided a method for providing a solution to protecting a bumper portion of an ejection port door in a military specification styled rifle that excludes manufacturing molds and rifle maintenance tools, the method comprising 1) Printing at least one cover as described in previous embodiments from a three dimensional printer using material capable of dampening sound and withstanding impact against a receiver portion of the rifle when initiating a firing sequence of the rifle, 2) snapping the cover upon the bumper portion of the rifle, and 3) removing the cover when it becomes non-operational and replacing it as needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a recess side of a cover in accordance with one embodiment of the current invention. 
         FIG. 2  is an opposite view of the recess side accordance with the embodiment illustrated in  FIG. 1 . 
         FIG. 3  is a top view of the cover in an embodiment of the current invention. 
         FIG. 4  is a side view of an embodiment of the current invention. 
         FIG. 5  is a side perspective view of an embodiment of the current invention. 
         FIG. 6  is a top perspective view of the inventive cover as it is placed atop a bumper on an ejection port door. 
         FIG. 7  is a rear view of the embodiment of the invention shown in  FIG. 6 . 
         FIG. 8  is a top view of the embodiment of the invention shown in  FIG. 6 . 
         FIG. 9  is a side view of the embodiment of the invention shown in  FIG. 6 . 
         FIG. 10  is a side view cover as it rests against the lower receiver portion of a military specification rifle. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The current invention concerns a cover for the center latch or bumper on an existing AR-15, M-16, AR-10 or other military specification rifle that has an ejection port with a door that is forced open by the rearward motion of the bolt during a firing sequence. The inventive cover may be created with any number of materials, including but not limited to plastics, polymers, and others materials known in the arts to provide dampening, either in a traditional manufacturing mold, 3D printer, by a liquid form mold poured upon the bumped and cured, or other means known in the arts. The cover may comprise a recess that approximates the shape of the generally rectangular bumper on ejection port, though the recess may have other shapes within the scope of the invention, especially in rifles that may have a bumper of a shape other than rectangular. In preferred embodiments, recess may comprise a negative mold of the bumper or tab, the recess having dimensions that are equal to or slightly greater than the bumper so that the cover may “snap-fit” over the bumper. 
     Referring now to  FIGS. 1-5  a cover in accordance with the current invention can be seen. Cover  10  may comprise an interface side  100  and a recess side  200 . Viewed from  FIGS. 1-3  or of the interface or recess sides, cover  10  may have a generally rectangular outline. As illustrated in  FIGS. 1-5 , cover  10  may further comprise a first  20 , second  30 , third  40  and fourth  50  border. Borders may be defined at their ends by border intersections each having a height.  FIG. 4  shows two classes of intersections, a greater intersection  60  and a lesser intersection  70 , the greater intersection  60  having a greater height than the lesser intersection  70 . Although intersections are depicted as having a generally linear height, other profiles may be within the scope of the invention. Intersections may have curved portions in both their height or about the lateral transition area between each of the borders. 
     The first border  20  may be defined on each end by lesser intersection  70   s , so that the first border  20  has essentially a rectangular configuration, perpendicular to the recess surface  260 . Similarly, the third border  40  may be defined on each end by greater intersections  60 , so that the first border  20  has essentially a rectangular configuration, perpendicular to the recess side  260 . In other embodiments not shown, the relationship between the border and the recess side may be that other than perpendicular. 
     The second border  30  may be defined at on the end proximal to the third border  40  by a greater intersection  60 , and then on the other opposite end by a lesser intersection  70  with the first border  20 . Similarly, the fourth border  50  may be defined at on the end proximal to the third border  40  by a greater intersection  60 , and then on the other opposite end by a lesser intersection  70  with the first border  20 . Thus, as depicted in  FIGS. 3-5  the second  30  and fourth border  50  have ends corresponding to the first border  20  and second border  30 , such ends respectively represent a first height, and a second height. 
     Interface side  100  may comprise at least one face that may interface with the receiver portions of a rifle. In  FIG. 10 , interface side  100  may interface in a relatively flush relationship with a surface of the lower receiver  360  of the rifle when the ejection port door  300  opens when a firing sequence is initiated. According to the embodiment in  FIGS. 3-9 , interface side  100  comprises two faces. First, a top face  110  is shown in  FIGS. 3-9  as having a plane perpendicular to the intersections between any of the borders of the cover  10 , and having a parallel plane as that of the recess side  200  of the cover  10 . Second, a lower face  120  is shown as having a planar profile extending diagonally from the interface surface  110  to the first border  20  of the cover  10 . In operation of the embodiment shown in  FIGS. 3 and 5 , lower face  120  may present diagonally, allowing a user, for replacement ordering purposes, to clearly see a manufacturer&#39;s logo or information that would be etched upon the lower surface. In other embodiments within the scope of the invention, the interface surface  110  may have other geometric configurations, including those with curved or convex profiles. For example, in an embodiment not show in illustration, the lower face  120  may have a curved indentation in the area where the cover  10  meets the lower receiver in  FIG. 10 . 
     The recess side  200  of the cover  10  is depicted in  FIGS. 1 and 2  as having a recess  210  that may snap onto a tab of an ejection port, as shown further in  FIG. 6 . Recess  210  may be defined by at least one wall that serves as an interior perimeter  215  of the recess side, the at least one wall having a height. As shown in FIGS, a first, second  230 , third  240 , and fourth  250  wall form a rectangular interior perimeter  215  of the recess  210 , the first  220 , second  230 , third  240 , and fourth  250  walls correlating (for the purposes of this embodiment) to the first  20 , second  30 , third  40  and fourth  50  borders of the cover  10 . The recess  210  may have, at its interior portion joining the walls, at least one surface. According to the embodiment shown in the  FIGS. 1-2 , recess surface  260  has both a base surface  270  and a diagonal surface  280 . Base surface  270  may be parallel in the planar profile of the interface surface  110  and perpendicular to the second  230 , third  240  and fourth  250  walls of the recess  210 . Diagonal surface  280  may be parallel to the planar profile of the lower face of the interface surface  110  in  FIGS. 3-5 , extending from the base surface towards the first wall. 
     Recess side may comprise a perimeter exterior that, according to  FIGS. 1-2 , may be located contiguous of the first, second, third and fourth borders. The cover  10  may include a reduced margin  75  between the recess side  200  and the borders, the reduced margin breaking or biasing towards the interface side. Reduced margin may extend between the recess side and borders as shown in  FIG. 1 or 2 , or at the interface surface according to embodiments not illustrated. As seen in  FIG. 1 , reduced margin is structured as a beveled margin  75  that may be utilized with the second  30  and fourth  50  border. In this embodiment, the beveled margin  75  exists along the entire margin at the recess side  200  of the border, providing an open space when the cover  10  is snapped in place onto the bumper  310  of the ejection port door  300 . Beveled margin  75  may have a linear or curved profile from the recess side  200  to the border. In embodiments not shown, beveled margin(s)  75  may only appear in portions of one or more borders. Beveled margin  75  may further appear in all the borders of the cover  10 . Though it may be seen in  FIG. 4  that the interface side  100  of the borders have a slightly curved profile, the concept of the beveled margin  75  may be understood to be a deviation from the recess side  200  of the cover  10  to the any of the borders so that a fingernail or tool could easily fit under the beveled margin  75  to dislodge the cover  10  from its snap-locked position on the bumper  310  of the ejection port. 
     The reduced margin  75  of the inventive cover  10  offers an important inventive distinction over the prior art of operating military spec rifles with ejection port doors. Designing a reduced margin  75  at an exterior portion of the recess side  200  of the cover  10  resulted in unexpected functionalities, superior to what was expected. First, an operator is able to pry the cover  10  from the ejection port bumper  310  using his or her fingernail or a tool with an edge, making removal and replacement of the cover  10  much simpler than other forms of maintenance on a firearm. It especially is a marked improvement of replacing a degraded and worn receiver, saving time and not an unsubstantial amount of money if using a gunsmith. Second, the reduced margin  75  of the cover  10  allows a small amount of flexure, enabling the user to push the recess  210  of the cover  10  upon a similarly proportioned ejection port bumper  310  manually and without great effort. The cover  10  seats upon the bumper  310  in a snap fit relationship that is able to sustain repeated mechanical trauma from striking the receiver of the rifle without the cover  10  failing through fracture or slipping off the bumper. The ability to dampen an otherwise loud, location-revealing mechanical report has great utility in military and other strategic firearm scenarios. The ability to manually apply or change out the inventive cover  10  in virtually any environment, without tools is one that has gone lone unaddressed in the arts. 
     The cover may be manufactured in a number of different dimensions. In a preferred embodiment, the recess has a length, width, and height. The length correlates to the distance from the first wall  220  to the third wall  240 . The width correlates to the distance between the second wall  230  and the fourth wall  250 . The depth correlates to the distance between the interior perimeter  215  of the recess  210  and various points that are disposed at the end of a perpendicular line from the interior perimeter  215  to the recess surface  260 . In the embodiment shown in  FIGS. 1-2 , recess surface includes the base surface  270  and diagonal surface  280 . Thought the following dimensions are not intended to be dispositive or exclusive in scope, they have been found to provide excellent results and benefits described herein when reduced to the approximation measurements that follow: Recess may have a length of 12.71 mm and a width of 11.35 mm. Put another way, first wall be considered a width of the interior perimeter of the recess and second wall may be considered a length of the interior perimeter of the recess. Regarding the depth of the recess  210 , the first wall  220  may have a height of 0.75 mm. The third wall may have a height of 2.6 mm. As shown, second and fourth walls may vary in height along the diagonal surface. The base surface may have a length of 3.42 mm as measured along the second and/or fourth walls. The distance between the base surface and the interface surface may be 1.5 mm, which may be referenced herein as the thickness of the interface cover, though the thickness of other portions of the cover may vary. The bevel margin(s)  290  between the exterior of the recess surface and border(s) may have a length of 0.75 mm and be set at a 150 degree angle, given that the 180 degree horizon is the recess surface from interior perimeter to the exterior perimeter. The first and third borders may have a width of 14.35 mm, as measured between their two respective intersections. The second and fourth borders may have a length of 15.71 mm, as measured between their two respective intersections. In another embodiment of this invention, each of these measurements sans the bevel margin may have a range of + or −1 mm. The bevel margin may have a range of 1 degree to 170 degrees, and a length from 0.25 mm to 2.5 mm. In the embodiment shown in  FIGS. 1-2 , the bevel margin may be in the 140-170 range, as breaking from a line extending from the exterior perimeter of the recess side. 
     As depicted in  FIGS. 6-10  the cover  10  is shown fitted upon a bumper  310  of an ejection port door  300 . Ejection port door  300  comprises a spring mechanism  320 , including a spring lock  330  emerging from a spring case  340 , as well as a hinge  350  that allows a path of the door  300  from an upper receiver portion  360  to a lower receiver portion  360 . The spring mechanism  320  communicates and locks into a radius cut into the upper receiver portion of a rifle, typically after a firing sequence is completed. The user may manually return the door  300  to the upper receiver  360  portion of the rifle. When a firing sequence begins, the action upon the bolt forcefully releases, unlocking the spring mechanism, and the cover  10  makes contact with the metal portion of the lower receiver portion, as seen in  FIG. 10 . The cover  10  dampens the report that would typically be produced from the opening of the door and prevents degrading of the receiver  360 . 
     It will be seen therefore, that the present invention is well adapted to carry out the ends and advantages mentioned, as well as those inherent therein. While the presently preferred embodiments of the apparatus has been shown for the purposes of this disclosure, numerous changes in the arrangement and construction of parts may be made by those skilled in the art. All of such changes are encompassed within the scope and spirit of the appended claims.