Variable-power riflescope with range-compensating reticle and a field stop diaphram centered off the optical axis

• US 4,497,548 A
• Filed: 12/13/1982
• Issued: 02/05/1985
• Est. Priority Date: 12/05/1980
• Status: Expired due to Term

• Current Assignee: Burris Company Incorporated
• Original Assignee: Burris Company Incorporated
• Inventors: Burris, Donald J.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/449,400
• Time in Patent Office: 785 Days
• Field of Search: 350/560, 350/561, 350/562, 350/566
• US Class Current: 359/422
• CPC Class Codes: G02B 23/14 Viewfinders for photographic apparatus G03B13/02

Abstract

This invention relates to a variable-power riflescope equipped with a novel range-compensating reticle system characterized by separating the horizontally-disposed element thereof from the vertically-disposed one, locating the former in the forward focal plane displaced off the optical axis and locating the latter in the rear focal plane while, at the same time, displacing the aiming point carried by the latter off the optical axis also. The resulting reticle system functions in cooperation with the means for varying the degree of image magnification in such a way that the shooter is enabled to precisely define two ranges, one near and one far, and shoot quite accurately at any distance therebetween. A further refined version of the same system allows the shooter to actually determine the range to a chosen target of known dimension an unknown distance away and in so doing automatically adjust the aiming point defined by the reticle system to coincide with the point of impact of the bullet. While the range is thus determinable, it is unnecessary to know since the optical system has made the required adjustment automatically that is needed to compensate for the trajectory of the bullet at such range. A field stop diaphragm is centered on the aiming point.

Claims

1. In a variable-power riflescope having an optical axis defined by an optical system including objective lens means at the front end thereof adapted to reproduce an inverted image of a distant real object in a first image plane spaced rearwardly thereof, erector lens means mounted for axial movement to the rear of the first image plane adapted to reproduce an erect image of the real object in a second image plane spaced therebehind at varying degrees of magnification, eyepiece lens means located behind the second image plane adapted to focus upon the erect image reproduced therein, and means connected to the erector lens means operative upon actuation to shift the axial positions thereof so as to vary the degree of image magnification, the improvement which comprises:

first reticle means mounted in the first image plane carrying first aiming indicia visible through the eyepiece lens means, second reticle means mounted in the second image plane carrying second aiming indicia visible through the eyepiece lens means in superimposed relation upon the first aiming indicia, said first and second aiming indicia cooperating when thus superimposed to define a first aiming reference in substantial horizontal alignment with a point of bullet impact at a first preselected range, point-definiing means defining a point located in the second image plane displaced vertically with respect to the optical axis, said point-defining means being responsive to increases in the degree of image magnification so as to open a gap between it and the first aiming reference, and said point-defining means when so moved defining a second aiming reference in vertically-spaced relation to said first aiming reference and in substantial horizontal alignment with a point of bullet impact at a different range, and means in said second image plane defining a field stop diaphragm with said point-defining means at the center thereof.

2. An improvement in a variable-power riflescope having an optical axis defined by an optical system including objective lens means at the front end thereof adapted to reproduce an inverted image of a distant real object in a first image plane spaced rearwardly thereof, erector lens means mounted for axial movement to the rear of the first image plane adapted to reproduce an erect image of the real object in a second image plane spaced therebehind at varying degrees of magnification, eyepiece lens means located behind the second image plane adapted to focus upon the erect image reproduced therein, and means connected to the erector lens means operative upon actuation to shift the axial positions thereof so as to vary the degree of image magnification, the improvement comprising:

first reticle means mounted in the first image plane carrying a horizontal component of a first aiming indicia visible through the eyepiece lens means, second reticle means mounted in the second image plane carrying a vertical component of said first aiming indicia and a second aiming indicia coincident with said vertical component, said vertical component being visible through the eyepiece lens means in superimposed intersecting relation upon said horizontal component of the first aiming indicia, said intersection defining a first aiming reference displaced beneath the optical axis a first predetermined distance, said second reticle means being eccentrically-apertured to define a field stop diaphragm encircling said first aiming reference in concentric relation thereto, said second aiming indicia defining a point located in the second image plane on said vertical component, said point being displaced above the optical axis a second predetermined distance, said first predetermined distance being selected to permit horizontal alignment of said first aiming reference with a location of bullet impact at a preselected close range, said first displacement being magnified by increases in the degree of image magnification to open a viewed vertical gap between said point and said first aiming reference, said second preselected distance being selected to permit said point to be placed in substantial horizontal alignment with a location of bullet impact at a long range at a selected magnification of the viewed image, said first and second aiming indicia bracketing a series of ranges between said close and long range whereby a shooter can estimate a point of bullet impact and a corresponding aiming reference anywhere therebetween so long as said selected degree of image magnification is maintained.

3. The improved variable-power riflescope as set forth in claim 2 wherein the point is displaced above the optical axis a predetermined distance selected to place same in superimposed relation upon the first aiming reference at the minimum degree of image magnification.

4. The improved variable-power riflescope as set forth in claim 2 wherein the eccentrically located field stop diaphragm is located in the second image plane.