Wide-Ratio Bow Limb Structure for Lower Stress Distribution
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Solution Overview
Problem
Existing archery bows face challenges with high stress levels in their limbs, especially when at-rest and drawn, necessitating a need for improved bow structures.
Innovation Solution
The archery bow design incorporates a frame with first and second limb assemblies supporting rotatable members, featuring a wide limb ratio, with each limb segment having a width that is at least 26% of its length, providing a greater surface area for reduced stress and increased longevity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional limb designs are used, then the bow can be constructed with simpler materials, but the limbs experience high stress levels and reduced longevity
Solution Approach 1:
The limb is divided into multiple segments with different width-to-length ratios. The first limb segment has a different width-to-length ratio than the second limb segment, allowing each segment to be optimized for its specific functional requirements while reducing overall stress levels and improving longevity.
Solution Approach 2:
Different portions of the limb are given different geometric properties. Specifically, the first and second limb segments have different width-to-length ratios, creating local variations in stress distribution that optimize both strength and weight efficiency throughout the limb structure.
2Stress or pressure
If the limb width is increased to reduce stress, then the bow becomes heavier, but the limbs can withstand higher stress levels
Solution Approach 1:
The limb is segmented into multiple portions with different width-to-length ratios. This allows the limb to have greater width in stress-critical areas while maintaining lighter construction in other areas, optimizing the balance between stress resistance and overall weight.
Solution Approach 2:
The limb structure incorporates local variations in width-to-length ratio, with certain segments having greater width relative to their length to handle higher stresses, while other segments can be lighter, thereby reducing overall bow weight while maintaining necessary stress resistance.
3Reliability
If the limb width-to-length ratio is increased, then stress distribution improves, but the limb becomes more complex to manufacture
Solution Approach 1:
The limb is divided into discrete segments that can be manufactured separately and then assembled. This segmentation allows for simplified manufacturing of individual components while achieving the complex overall stress distribution pattern through the combination of segments with different width-to-length ratios.
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
The wide limb ratio design reduces stress levels and increases longevity by distributing stress more evenly across the limb surfaces, allowing for a lighter and more efficient bow construction.
Implementation Method 1
Archery bows typically use flexible limbs to store energy. The limbs can be highly stressed members.
Data Source
AI summary
In some embodiments, an archery bow comprises a frame, a first limb assembly supporting a first rotatable member and a second limb assembly supporting a second rotatable member. The first rotatable member comprises a cam. A bowstring extends between the first rotatable member and the second rotatable member. A power cable is in communication with the cam. The first limb assembly has a width and a length, wherein the width is at least 26% of the length. In some embodiments, the width is at least 28% of the length.