Telescopic Gun Sight with Offset Reticle for Bullet Drop Compensation
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Solution Overview
Problem
Adjusting the point of aim in telescopic gun sights for distant targets is challenging due to small elevation adjustment steps and mechanical instability caused by repeated adjustments, making it difficult to compensate for bullet drop effectively.
Innovation Solution
A zoom telescopic gun sight design where the reticle is mounted at a vertical offset with respect to the optical axis, allowing the point of aim to be adjusted by changing the magnification, eliminating the need for separate elevation adjustments and providing automatic bullet drop compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical elevation adjustment knobs are used to compensate for bullet drop, then the point of aim can be adjusted, but the adjustment steps are too small (0.25 MOA or 0.1 milliradian per click) making it difficult to adjust for targets at long distances
Solution Approach 1:
The patent combines the zoom magnification function with the bullet drop compensation function into a single control mechanism. By mounting the reticle at a vertical offset from the optical axis, adjusting the zoom simultaneously changes both the magnification and the apparent position of the reticle on the target, providing large-step elevation adjustment for long-distance targets without requiring separate elevation knobs.
Solution Approach 2:
The zoom control is given dual functionality: it performs both magnification adjustment and bullet drop compensation. The offset-mounted reticle ensures that as magnification changes, the reticle's position relative to the target image automatically adjusts to compensate for bullet trajectory, eliminating the need for dedicated elevation adjustment mechanisms.
2Adaptability or versatility
If repeated mechanical elevation adjustments are made, then the point of aim can be adjusted for different distances, but the spring tension causes a shift in the sight's original point of aim
Solution Approach 1:
The patent merges the distance adaptation function with the zoom mechanism. Since the reticle is offset-mounted, changing magnification automatically adjusts the point of aim for different distances without requiring mechanical elevation shifts that could destabilize the mounting system.
Solution Approach 2:
The patent replaces the mechanical elevation adjustment system (knobs, springs, and linkages) with an optical solution. The offset reticle mounted at the eyepiece focal plane allows distance compensation through optical magnification changes rather than mechanical movement, eliminating spring tension and mechanical instability issues.
3Ease of operation
If the reticle is mounted coplanar with the eyepiece focal plane on the optical axis, then the reticle appears centered in the field of view, but the point of aim cannot be adjusted for bullet drop at long distances
Solution Approach 1:
The patent introduces asymmetry by mounting the reticle at a vertical offset from the optical axis rather than symmetrically on the axis. This asymmetric positioning creates a geometric relationship where zoom magnification changes automatically shift the reticle's apparent position on the target, enabling bullet drop compensation while maintaining field of view centering.
Solution Approach 2:
The patent changes the geometric parameter of reticle mounting position from (0,0) on the optical axis to an offset position (0, δ). This parameter change transforms the zoom mechanism's effect, causing magnification adjustments to simultaneously produce both magnification and elevation adjustment, thereby enabling bullet drop compensation.
4Measurement precision
If two separate adjustments (zoom and elevation) are required to shoot at distant targets, then precise control is possible, but the adjustment process becomes complex and time-consuming
Solution Approach 1:
The patent merges two separate adjustment operations (zoom and elevation) into a single zoom control operation. The offset-mounted reticle ensures that zoom magnification changes automatically provide both magnification and elevation adjustment in the correct proportion for bullet drop compensation, eliminating the need for sequential adjustments.
Solution Approach 2:
The reticle is pre-positioned at a specific vertical offset distance from the optical axis, calculated based on the firearm's ballistics. This preliminary positioning ensures that as the shooter zooms to different magnifications, the reticle automatically moves to the correct elevation for compensating bullet drop at various distances, eliminating the need for real-time calculation or separate elevation adjustments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables easy and straightforward aiming at long distances by using the zoom feature for both magnification and bullet drop compensation, reducing mechanical interference and simplifying the adjustment process.
Implementation Method 1
an objective lens 1 which forms a first image of the target on the objective focal plane 2
Implementation Method 2
An image-erecting means comprising a pair of lenses 3a and 3b relays this first image to the eyepiece focal plane 4 and forms a second, upright and laterally correct image there
Implementation Method 3
An eyepiece lens 5 takes this second image and produces a virtual magnified image for the shooter to see
Data Source
AI summary
This invention teaches a telescopic gun sight wherein the sight's magnification and point of aim can be adjusted simultaneously using the zoom knob. Once the sight is zeroed-in at a set distance, say 100 yards, it will automatically compensate for bullet drop at longer distances as magnification is increased.