Adjustable Rear Iron Sight for a Fire Arm

Abstract

An adjustable iron sight for firearms includes compensation for projectile drop. The projectile drop compensation moves the sight aperture to compensate for projectile drop. Use of the compensation will allow aiming directly at the target without having to visually compensate for projectile drop. The projectile drop compensation mechanism includes a multi-position manually operable wheel and cam that is profiled to match the trajectory of the particular firearm and load. As there are many possible loads that could be used with a particular firearm, the multi-position cam is interchangeable to allow changing to a cam that is matched to the specific load that is desired.

1 . An adjustable rear iron sight for a firearm comprising:
 a rear sighting element for mounting at a rear of the fire arm and defining a visible alignment portion for visual alignment by the user with a front sighting element;   a mounting member having mounting elements for attachment of the mounting member to the firearm;   an adjustable member carried on the mounting member and adjustably movable upwardly and downwardly relative thereto;   the sighting element being mounted on the adjustable member so that the upward and downward adjustment acts to change the height of the sighting element on the firearm so as to compensate for projectile drop over different distances;   a manually rotatable wheel mounted on the mounting member for manual rotation by the user about an axis of the wheel;   the wheel carrying a cam for rotation therewith having a generally spiral cam surface defining a spirally changing radius from the axis for engaging an abutment on the adjustable member and moving the adjustable member to a height determined by the radius at any selected position on the spiral cam surface;   the wheel having a plurality of distance markings on a visible surface thereof angularly spaced around the axis for selection by the user of a required distance marking by rotating the wheel to a selected angular position determined by selection of the required distance marking;   the spiral cam surface having a profile of radius changes calibrated such that the distance markings are each associated with a respective required height of the adjustable member.   
     
     
         2 . The adjustable rear iron sight according  claim 1  wherein there is provided with the mounting member, sighting element and adjustable member a plurality of wheels each having a cam with a different profile of the cam surface where the cam spiral cam surface of each wheel has a profile of radius changes calibrated relative to a different shot load for the fire arm. 
     
     
         3 . The adjustable rear iron sight according  claim 1  wherein the wheel is readily removable and replaceable for replacement with a second wheel having a cam with a different profile of the cam surface where the cam spiral cam surface of each wheel has a profile of radius changes calibrated relative to a different shot load. 
     
     
         4 . The adjustable rear iron sight according  claim 1  wherein the wheel is readily removable and replaceable for replacement with a second wheel having a cam with a different profile of the cam surface where the cam spiral cam surface of each wheel has a profile of radius changes calibrated relative to a different fire arm. 
     
     
         5 . The adjustable rear iron sight according  claim 1  wherein the wheel is attached to the mounting member by a single screw extending along the axis and defining a shaft for rotation of the wheel. 
     
     
         6 . The adjustable rear iron sight according  claim 1  wherein the rear sighting element is mounted on the adjustable member for side to side movement for adjustment of the rear sighting element to compensate for windage. 
     
     
         7 . The adjustable rear iron sight according  claim 1  wherein the rear sighting element is mounted on the adjustable member by an adjustment screw. 
     
     
         8 . The adjustable rear iron sight according  claim 1  wherein the adjustable member is mounted on the mounting member by a pair of upstanding pins allowing sliding movement of the adjustable member on the mounting member. 
     
     
         9 . The adjustable rear iron sight according  claim 8  wherein the pins carry springs for biasing the adjustable member onto the cam surface. 
     
     
         10 . The adjustable rear iron sight according  claim 1  wherein the wheel is mounted between the pins below the adjustable member and the springs bias the adjustable member downwardly onto the cam surface. 
     
     
         11 . The adjustable rear iron sight according  claim 1  wherein the wheel and the mounting member include cooperating elements for restraining the wheel in a plurality of angular positions corresponding to the distance markings on the wheel. 
     
     
         12 . The adjustable rear iron sight according  claim 1  wherein the cooperating elements comprise series of recesses in one of the mounting member or the wheel and a spring biased ball for engaging into the recesses and carried on the other of the mounting member or the wheel. 
     
     
         13 . The adjustable rear iron sight according  claim 1  wherein the mounting member comprises an upstanding block with a first upstanding side surface having the mounting elements for attachment of the mounting member to the firearm and a second parallel upstanding side surface carrying the wheel. 
     
     
         14 . An adjustable rear iron sight for use with different firearms having different available shot loads comprising:
 a rear sighting element for mounting at a rear of the fire arm and defining a visible alignment portion for visual alignment by the user with a front sighting element;   a mounting member having mounting elements for attachment of the mounting member to the firearm;   an adjustable member carried on the mounting member and adjustably movable upwardly and downwardly relative thereto;   the sighting element being mounted on the adjustable member so that the upward and downward adjustment acts to change the height of the sighting element on the firearm so as to compensate for projectile drop over different distances;   and a plurality of manually rotatable wheels each arranged to be readily removably mounted on the mounting member;   each wheel being arranged, when mounted, for manual rotation by the user about an axis of the wheel;   each wheel carrying a cam for rotation therewith having a generally spiral cam surface defining a spirally changing radius from the axis for engaging an abutment on the adjustable member and moving the adjustable member to a height determined by the radius at any selected position on the spiral cam surface;   each wheel having a plurality of distance markings on a visible surface thereof angularly spaced around the axis for selection by the user of a required distance marking by rotating the wheel to a selected angular position determined by selection of the required distance marking;   each spiral cam surface having a profile of radius changes different from that of the other cam surfaces of the different wheels and calibrated such that the distance markings are each associated with a respective required height of the adjustable member relative to a different shot load for a selected fire arm.   
     
     
         15 . An adjustable rear iron sight for a firearm comprising:
 a rear sighting element for mounting at a rear of the fire arm and defining a visible alignment portion for visual alignment by the user with a front sighting element;   an upstanding mounting block with a first upstanding side surface having mounting elements for attachment of the upstanding mounting block to the firearm and a second parallel upstanding side surface;   an adjustable member carried on a top of the upstanding mounting block and adjustably movable upwardly and downwardly relative thereto;   the sighting element being mounted on the adjustable member so that the upward and downward adjustment acts to change the height of the sighting element on the firearm so as to compensate for projectile drop over different distances;   a manually rotatable wheel mounted on the second side surface of the upstanding mounting block for manual rotation by the user about an axis of the wheel extending at right angles to the second side surface;   the wheel carrying a cam for rotation therewith having a generally spiral cam surface defining a spirally changing radius from the axis for engaging an abutment on the adjustable member and moving the adjustable member to a height determined by the radius at any selected position on the spiral cam surface;   the wheel having a plurality of distance markings on a visible surface thereof angularly spaced around the axis for selection by the user of a required distance marking by rotating the wheel to a selected angular position determined by selection of the required distance marking;   the wheel and the mounting member include cooperating elements for restraining the wheel in a plurality of angular positions corresponding to the distance markings on the wheel;   the spiral cam surface having a profile of radius changes calibrated such that the distance markings are each associated with a respective required height of the adjustable member.   
     
     
         16 . The adjustable rear iron sight according  claim 15  wherein the wheel is attached to the mounting member by a single screw extending along the axis and defining a shaft for rotation of the wheel. 
     
     
         17 . The adjustable rear iron sight according  claim 15  wherein the rear sighting element is mounted on the adjustable member for side to side movement for adjustment of the rear sighting element to compensate for windage. 
     
     
         18 . The adjustable rear iron sight according  claim 15  wherein the rear sighting element is mounted on the adjustable member by an adjustment screw. 
     
     
         19 . The adjustable rear iron sight according  claim 15  wherein the adjustable member is mounted on the mounting member by a pair of upstanding pins allowing sliding movement of the adjustable member on the mounting member. 
     
     
         20 . The adjustable rear iron sight according  claim 19  wherein the pins carry springs for biasing the adjustable member onto the cam surface.