Patent Publication Number: US-6338219-B1

Title: Bracket-integrated back-up optical sight

Description:
ORIGIN OF THE INVENTION 
     The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used, licensed by or for the Government for any governmental purpose without payment of any royalties thereon. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to optical sights, and more particularly to an optical sight that is integrated into an optical scope&#39;s mounting bracket to serve as a back-up optical sight. 
     BACKGROUND OF THE INVENTION 
     Optical scopes for weapons have become increasingly sophisticated as they make use of advanced optics and/or lasers. For ease of assembly and replacement in case of failure, the optical scope is typically mounted onto a bracket that is attached to a weapon. Unfortunately, a replacement optical scope may not be readily available in a field application. In such instances, the weapon may be useless unless the weapon is equipped with a back-up optical sight. 
     One type of back-up optical sight is described in U.S. Pat. No. 5,659,965. This back-up optical sight includes a peepsight and post that flip up adjacent to the weapon&#39;s optical scope. However, the peepsight and post can be easily damaged and add weight to the weapon. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a readily available back-up optical sight for a weapon. 
     Another object of the present invention is to provide a back-up optical sight for a weapon that is compact and rugged. 
     Still another object of the present invention is to provide a back-up optical sight for a weapon that is always aligned with the weapon&#39;s optical scope. 
     Yet another object of the present invention is to provide a back-up optical sight that does not add weight to a weapon. 
     Other objects and advantages of the present invention will become more obvious hereinafter in the specification and drawings. 
     In accordance with the present invention, an optical sight includes a base such as a bracket that can support an optical scope. The bracket defines a bore therethrough such that an optical line-of-sight is defined that is parallel to the line-of-sight of the optical scope that would be coupled to the bracket. A post is adjustably mounted in the bracket to extend vertically upward into the bore at a forward end of the bracket so that the post&#39;s outboard end can be selectively positioned in the bore along a vertical line extending through the bore. A plate having an aperture formed therethrough is adjustably mounted to the bracket across the bore at an aft end of the bracket in a way that the aperture can be selectively positioned along a horizontal line that is perpendicular to the vertical line defined by the post. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments and to the drawings, wherein corresponding reference characters indicate corresponding parts throughout the several views of the drawings and wherein: 
     FIG. 1 is a perspective view from the forward end of an embodiment of the bracket-integrated back-up optical sight according to the present invention; 
     FIG. 2 is a perspective view from the aft end of the bracket-integrated back-up optical sight; 
     FIG. 3 is a cross-sectional view taken along the central longitudinal plane of the bracket-integrated back-up optical sight illustrated in FIG. 1; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  in FIG. 3; 
     FIG. 5 is an enlarged isolated view of the post used in the forward portion of the bracket-integrated back-up optical sight; and 
     FIG. 6 is an enlarged cross-sectional view of the aperture plate used in the aft portion of the bracket-integrated back-up optical sight. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and more particularly to FIGS. 1 and 2, a bracket-integrated back-up optical sight is illustrated in forward and aft perspective views, respectively, and is referenced generally by numeral  10 . By way of illustrative example, back-up optical sight  10  is shown and will be described using an optical scope mounting bracket  12  for the United States Marine Corps&#39; shoulder-launched multi-purpose assault weapon (SMAW). However, it is to be understood that the present invention could make use of other optical scope mounting brackets or any other part of a weapon or weapon accessory that is properly positioned to serve as a back-up optical sight and that can be modified as will be described herein. 
     As is known in the art, mounting bracket  12  is attached to a weapon using mounting hole  120 . Once attached to the weapon, mounting bracket  12  can be rotated about mounting hole  120  to adjust the range of an optical scope (not shown) attached to mounting bracket  12 . This range adjustment is provided by a range drum (not shown) cooperating with a range drum receiver  121  on mounting bracket  12 . The optical scope is attached to a mounting rail  122 , the design of which is not a limitation of the present invention. Once attached to mounting rail  122 , the line-of-sight of the optical scope changes with the rotational movement of mounting bracket  12  in order to set the range of the weapon to which it is attached. 
     In accordance with the illustrated embodiment of the present invention, mounting bracket  12  is modified to provide a line-of-sight therethrough that is parallel to that of the line-of-sight of the optical scope that will be mounted thereto. For example, referring additionally to FIGS. 3 and 4, mounting bracket  12  can be configured or constructed to have a bore  124  at its forward end  125  and a bore  126  at its aft end  127  coupled to an internal slot  128  of mounting bracket  12 . The combination of bore  124  at forward end  125 , internal slot  128  and bore  126  at aft end  127 , provide the necessary line-of-sight through mounting bracket  12 . By integrating the line-of-sight in mounting bracket  12  and by making it parallel to the line-of-sight of the optical scope that attaches to mounting rail  122 , range is simultaneously set for the optical scope and for the present invention&#39;s optical sight. 
     Mounted in the bracket&#39;s line-of-sight is a post  14  (FIG. 1) serving as the forward portion of optical sight  10 , and a plate  16  (FIG. 21, serving as the aft portion of optical sight  10 . More specifically, post  14  includes a threaded portion  140  and a cylindrical portion  142  as best seen in FIG.  5 . Threaded portion  140  is threaded into mounting bracket  12  such that cylindrical portion  142  extends vertically into bore  124 . Threaded portion  140  has a head end  144  that is constructed (e.g., slotted, hex head, hex depression, etc.) to receive a screw/nut driver or hex head wrench so that cylindrical portion  142  can be raised/lowered in bore  124 . 
     Plate  16  provides the user with a viewing aperture  160  at aft end  127  of mounting bracket  12 . As illustrated in FIG. 6, viewing aperture  160  has a cylindrical portion  162  coupled to a conical portion  164 . Cylindrical portion  162  is sized to set the correct aperture size for optical sight  10  as is known in the art. Conical portion  164  expands angularly away from cylindrical portion  162  to eliminate the “tunnel effect” as a viewer&#39;s eye  11  looks through cylindrical portion  162 . At its top edge  166  and bottom edge  168 , plate  16  is shaped to form a dovetail fit with a corresponding dove tail notch  129  cut in aft end  127 . 
     Since it may be necessary to adjust the horizontal position of viewing aperture  160 , plate  16  can slide horizontally in slot  129 . That is, viewing aperture  160  can move along a horizontal line that is perpendicular to the vertical line defined by cylindrical portion  142  of post  14 . To adjust and fix the horizontal position of plate  16 , a variety of structures could be used. By way of example, screws  130  and  132  (e.g., hex head screws) are provided on either side of mounting bracket  12  as best seen in FIGS. 1 and 2, respectively. More specifically, each of screws  130  and  132  are threaded into mounting bracket  12  such that their longitudinal axes are parallel to the horizontal plane in which plate  16  can move, and such that their screw heads abut opposing side edges  167  and  169 , respectively, of plate  16 . To move plate  16  and viewing aperture  160  horizontally, one of screws  130  and  132  is backed out of mounting bracket  12  while the other is screwed into mounting bracket  12 . 
     The advantages of the present invention are numerous. By integrating an optical sight into an optical scope&#39;s mounting bracket, a back-up optical sight is provided should the optical scope fail. Further, since the bracket-integrated optical sight is aligned with the optical scope that would be attached to the bracket, the ranging operation performed by moving the mounting bracket simultaneously performs the ranging operation for the back-up optical sight. The bracket-integrated back-up optical sight is rugged and compact since it is fully protected within the confines of the existing optical scope mounting bracket. In addition, inclusion of the bracket-integrated back-up optical sight actually makes the weapon lighter since material is removed (e.g., bored out) from the optical scope&#39;s mounting bracket. 
     Although the invention has been described relative to a specific embodiment thereof, there are numerous variations and modifications that will be readily apparent to those skilled in the art in light of the above teachings. For example, post  14  could be mounted in other ways to allow its vertical adjustment and plate  16  could be mounted in other ways to allow its horizontal adjustment. The present invention could be incorporated into any optical scope&#39;s mounting bracket provided there was room to do so. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.