Abstract:
A gun sight base which is designed to allow the user to quickly adjust the elevation of the attached gun sight as a means to affect the trajectory of a projectile discharged from the host firearm. Provided is a removable, pre-calibrated adjustment cam which is in operational contact with the attached gun sight. A distance indicator is visible to the user to allow for rapid elevation adjustments without the need for tools.

Description:
This is a continuation application of U.S. application Ser. No. 12/317,948, filed Dec. 31, 2008, now abandoned the priority of which is hereby claimed. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The herein disclosed invention relates, in general, to optical gun sights for use with a firearm and specifically for optical gun sight mounts. 
     2. Description of the Prior Art 
     Telescopic and electronic gun sights for use on rifles and other firearms are well known in the prior art. Adapting these gun sights to various weapons, in general, involves mounting the gun sight containing an image of a red dot or other physical reticule which is used to designate and aim upon a target and a means for mounting the gun sight onto a weapon. In general, the preferred method of securing a gun sight to a mount was through the use of at least one ring which encircles the gun sight and a mount which is designed to be secured to a secondary surface such as a 1913 mil. Std. Rail that is parallel to the bore of the host firearm. These conventional systems rely on the ring or rings which encircle the gun sight to be securely mounted to a base which connects to a secondary surface such as a 1913 mil. Std. Rail commonly found on military and civilian firearms. 
     In some prior art examples the rings or mount may provide a means for adjustment which allow for horizontal and vertical adjustment of the gun sight to accommodate lateral and vertical changes in the sight line of the gun sight versus the bore of the host firearm. Another popular prior art solution is to provide a means by which the reticule of a gun sight may be adjusted to compensate for windage and elevation to “sight in” the host firearm at a target range after the gun sight has been mounted. These prior art solutions, while providing a means to “sight in” the weapon in a range environment, are not suitable solutions for those needing to adjust the elevation and trajectory of a discharged projectile using the gun sight in a combat or action shooting competition. These prior art solutions often require the use of small hand tools and provide a method of adjustment which is not calibrated for the specific weapon and ammunition being used by the shooter. It would, therefore, be desirable to provide a gun sight mount which allowed for rapid, pre-calibrated adjustments to the elevation of the mounted gun sight. Additionally, this system provides a removable, graduated cam is afforded the user that has visible witness marks present designating the target range that the projectile will impact and does not require the user to use any tools. 
     Objects and Advantages 
     Accordingly several objects and advantages of the present invention are
         (a) To provide an adjustable mount which uses a graduated, pre-calibrated adjustment cam to adjust the mount and thereby the attached gun sight&#39;s elevation thus affecting the trajectory of the host firearms discharged projectile.   (b) To provide an adjustment cam which has a series of witness marks visible to the user that specify, in yards or meters, the target range being selected.   (c) To provide an adjustable mount which is robust and does not require tools to affect the elevation of the provided mount.   (d) To provide an adjustable mount which may be adapted to work with various attachment mechanisms used to secure a gun sight to a base to include, but not limited to rings and simple screw attachment methods.
 
Still, further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
       

     SUMMARY 
     The present invention is designed to address the problem of adjusting the current target range of a gun sight by providing an apparatus which allows for the rapid adjustment of the target range through the external adjustment of the gun sights elevation, thereby affecting the trajectory of a discharged projectile. The herein described device accomplishes this by providing a vertically adjustable bridge which has a mount platform for the gun sight and may be secured to a base that attaches to the host firearm. From the standpoint of ballistics, the mount is designed to provide the correction in elevation to the scope according with the trajectory of the projectile. The mount has a graduated knob which is integral to the adjustment cam, with set distances, to be selected with one hand from the aiming position. In other words, the distance or target range can be selected while the shooter is looking though the gun sight. 
     The adjustable bridge is restricted to movement in one plane, which is the projectile trajectory plane and it is spring loaded against the base, forcing it upwardly. The front of the bridge rotates on a roll pin which is supported by the base. The lateral movement is restricted to the cam which confines the lever of the bridge to stay in a groove. The amount of vertical movement allowed to the adjustable bridge is determined by the cam in the shaft of the knob. 
     The amount of vertical movement afforded the adjustable bridge, or angle of adjustment, is calculated using the real trajectory of the projectile. Trajectory depends on the velocity which the projectile leaves the barrel. Two of the most significant factors concerning velocity variations are the bullet, or projectiles, caliber and the barrel length of the host weapon. Other factors can include temperature, elevation, and bullet shape to name a few, but these factors are not as significant in most cases as caliber and barrel length. 
     The adjustable mount is designed to be adapted to weapons of differing calibers and barrel lengths by simply removing the adjustment cam assembly and selecting one which is appropriately calibrated for the firearm in use. The adaptability of the optic and associated mount is significant considering that the cost of these items can equal or exceed, in some instances, the price of the firearm it is designed to be used with. The knob of the cam is labeled with the appropriate caliber and barrel length information to make identification easy. 
     The knob of the adjustment cam assembly has pre-set positions easy to select by a simple rotation of the knob. A spring loaded ball detent applies pressure against the base and a series of depressions prevent the knob from unintentional rotations or skipping resulting from vibration. 
     From the above, it may be seen that the present invention provides for a means of allowing quick adjustments in the vertical alignment of a gun sight with the bore of a weapon. Also provided is a means to calibrate the quick adjustments in vertical alignment to specific caliber and barrel length combinations through the use of pre-set adjustment cam assemblies. Many other features and uses will become obvious to one skilled in the art upon examination of the attached detailed description and the associated claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The novel features believed to be characteristic of the invention, together with further advantages thereof, will be better understood from the following description considered in connection with the accompanying drawings in which a preferred embodiment of the present invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. 
         FIG. 1  is an illustration showing an adjustable base for an optic on a firearm upper receiver, with an optic in place, according to the principles of the invention; 
         FIG. 2  is a perspective side view of the herein described invention; 
         FIG. 3  is a side perspective view thereof rotated 180 degrees from the illustration in  FIG. 1 ; 
         FIG. 4  illustrates a side view of the adjustable base for an optic; 
         FIG. 5  depicts an exploded perspective view thereof; 
         FIG. 6  depicts a view thereof rotated approximately 90 degrees; 
         FIG. 7  is side perspective view thereof rotated 180 degrees from the illustration in  FIG. 5 ; and 
         FIG. 8  illustrates a side perspective view of the adjustment cam assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Now referring to the drawings, the adjustable base assembly of the present invention, generally designated by reference numeral  1 , for an optic  50 , is shown and generally illustrated in the figures. While the assembly may include several components and auxiliary attachments to tailor the assembly for the particular application, in the simplest form, the present invention provides for a device utilizing a spring loaded rail which is in operational connection with a cam that allows the user to adjust the elevation of an auxiliary sighting device, specifically an electronic optic with a firearm. In the preferred embodiment, the required components include at least an adjustable gun sight bridge  10  with an optic mounting platform  11 , and an adjustment cam  20 , and a base  30  which interfaces with the host firearm. Additionally, other components that may be utilized in the assembly as required by the particular application include a throw lever retention system  31  or simply screws. 
     As was stated above, the adjustable base assembly  1  for an optic is designed to be used with a variety of sighting scopes such as the types typically used on any variety of prior art firearms including, shotguns, and rifles. Further, the terms “scope” or “gun sight” or “optic” as used herein, are to be understood as including all types of auxiliary sighting devices capable of being mounted on a firearm that are utilized in place of the standard iron sights already found on the firearm as manufactured, including but not limited to telescopic sights, electronic sights, night vision devices, range finding and illuminating devices. Also, as used herein, “fore end” or “front end” refers to the end of a component nearest the muzzle of the firearm, while “rear end” refers to the end of the component nearest the shooter or user. 
     The primary objective of the adjustable base assembly  1  for an optic of the present invention is the provision of a spring loaded adjustable gun sight bridge  10  connected to an optic mounting platform  11  where the angle of the platform is changed by the rotation of an adjustment cam  20 . The adjustment cam  20  is removable and provides calibrated adjustments for the user to select from. This is an important feature because as stated above many electronic sights do not have built in bullet drop compensators or a ready means by which elevation might be adjusted. 
     Turning now to the drawings in which like reference characters indicate corresponding elements throughout the several views, attention is directed to  FIGS. 1-4 . There is illustrated a firearm upper receiver  40  with an integral 1913 mil. std. rail  41 . A means to secure the base  30 , to the 1913 mil. std. rail  41 , is provided in the form of self adjusting throw levers  31 . The base  30  has an adjustable gun sight bridge  10  which pivots on a fixed roll pin located between two thru holes  13 A and  13 B located at the front end of the adjustable base assembly  1 . An optic mount platform  11  ( FIG. 4 ) is provided to allow for the mounting of an electronic gun sight  50 . The rear end of the adjustable gun sight bridge  10  has an indexing hook  14  which interacts with the elevation cam  21 . The adjustment knob  20  consists of three parts: the knob  22 , the elevation indicator  23  and the elevation cam  21  which may be rotated through use of the provided knob  20 . An opening  15  is provided in the adjustable base assembly  1  for an optic  50  to allow the elevation indicator  23  on the adjustment knob  20  to be seen by the user. 
       FIGS. 5-7  show an exploded view of the herein described device from three different angles. The attachment means  31  is comprised of a variety of parts which make up a throw lever system. This system is known in the prior art but nothing about its use is meant to imply that it is the only attachment means which may be used to secured the base  30  to a secondary surface such as a firearm upper receiver  40 .  FIGS. 7-8  have the attachment means  31  omitted from their respective views for purposes of clarity. Also illustrated are the spring  16 , support detent  17  and the bottom opening  18  in the adjustable gun sight bridge  10  which houses these parts when the device is assembled and in operation. 
     Best illustrated in  FIGS. 6-7  is the adjustment cam  20  opening  24  and the thru holes  25 A and  25 B which retain the adjustment cam assembly  20  in place. A series of detent holders  26  are present about the interior surface of the adjustment cam opening  24 . A spring  27  and ball detent  28  are present and fully shown in  FIG. 8 . 
     Depicted in  FIG. 8  are the adjustment cam assembly  20 , spring  27 , ball detent  28 , and the retainer clip  80 . The adjustment cam assembly  20  consists of the elevation cam  21 , knob  22 , elevation indicator  23 , recess  29  which houses the spring  27  and ball detent  28 , and a groove  81  which interacts with the retainer clip  80 . 
     The base  30  has a means by which it may be secured to the upper receiver  40  of a firearm or other secondary surface, shown herein in the form of a throw lever retention system  31 . An adjustable gun sight bridge  10  is connected to the base  30  by a roll pin  12  which slides through the front end of the bridge  10  and the thru holes  13 A and  13 B of the base  30 . The rear end of the bridge  10  has an indexing hook  14  which is curved down. On top of the adjustable gun sight bridge  10  is an optic mounting platform  11  which provides a place to secure the electronic optic  50 . On the bottom of the bridge  10  is an opening  18  which houses a spring  16  and support detent  17 . 
     On the rear of the base  30  are two thru holes  25 A and  25 B and an adjustment cam opening  24  which houses the adjustment cam assembly  20 . About the interior of the adjustment cam opening  24  are a series of detent holders  26  which interact with the spring  27  loaded ball detent  28  sandwiched between the knob  22  of the adjustment cam assembly  20  and the adjustment cam opening  24 . The spring loaded ball detent  28  prevents the unintentional movement of the adjustment cam assembly  20  by interacting with the detent holders  26 . The adjustment cam assembly consists of the knob  22 , elevation indicator  23  and the elevation cam  21 . A retainer clip  80  interacts with a groove  81  present about the exterior of the adjustment cam assembly  20  and secures the assembly in place. 
     Elevation cam  21  is in operational contact with the indexing hook  14  located at the rear end of the adjustable gun sight bridge  10 . As the knob is rotated clockwise the elevation cam  21  places downward force on the indexing hook  14  thereby lowering the rear of the gun sight bridge  10 . While the elevation cam  21  is pushing on the indexing hook  14  the spring  16  and support detent  17  housed under the bridge  10  in the opening  15  are being compressed. This provides an opposing direction of force against the movement resulting from the interaction of the elevation cam  21  and the indexing hook  14  and keeps the bridge  10  in a secured position. The pre-calibrated adjustment cam assembly  20  has an elevation indicator  23  which is displayed through an opening  15  in the base  30 . The knob  22  may be turned counter-clockwise to release the pressure placed on the indexing hook  14  and allow the spring  16  and support detent  17  to elevate the rear of the adjustable gun sight bridge  10 . 
     Various changes and modifications to the embodiments herein chosen for purposes of illustration will readily occur to those skilled in the art. To the extent that such modifications and variations do not depart from the spirit of the invention, they are intended to be included within the scope thereof, which is assessed only by a fair interpretation of the following claims. 
     CONCLUSION, RAMIFICATIONS AND SCOPE 
     Accordingly the reader will see that I have provided an adjustable sight mount for an optical gun sight which has been adapted to work with various prior art attachment mechanisms. A removable, pre-calibrated cam assembly is used to adjust the firing trajectory of the host weapon by adjusting the angle of the attached electronic sight in relationship to the firearms bore. The war fighter is provided with an elevation indicator so that he will know at what range the projectiles will be point of aim, point of impact. The adjustable gun sight bridge may be adapted to other prior art mounts and used with a variety of different optics currently available on the market. No tools or other items are required for the war fighter to use this device. 
     Another embodiment of the adjustable sight mount could use thumb screws to secure the base to a firearm or other secondary structure. Further, a longer base could be utilized so that a traditional magnified optic could be secured to an extended adjustable gun sight bridge. 
     While my above drawings and description contain much specificity, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. 
     Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.