Compound Bow Cam System Two-Plane Alignment
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Solution Overview
Problem
Compound bow cam systems often suffer from synchronization issues and twisting effects due to wear, thermal changes, and improper maintenance, leading to inaccuracies and noise in arrow shooting.
Innovation Solution
A compound archery bow system with a two-plane cam assembly configuration, where the upper and lower cam modules are aligned in a common plane, allowing for dual-purpose cam modules that simultaneously take up and let out power cords, reducing twisting forces and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If cam assemblies are mounted to forked or slotted ends of limbs to increase arrow speed, then arrow exit velocity is improved, but twisting effects on cam assemblies increase, creating additional shooting errors and noise
Solution Approach 1:
The patent transitions from a conventional single-plane cam assembly arrangement to a two-plane configuration. The first plane contains the bowstring pulley and power cord take-up/let-out mechanisms, while the second plane contains the cam assemblies themselves. This dimensional separation allows the cam assemblies to be mounted on the forked or slotted ends of the limbs without creating twisting effects, as the power cords are routed through the first plane while the cam assemblies rotate in the second plane, eliminating the harmful torsional forces that cause noise and shooting errors.
2Measurement precision
If upper and lower pulleys or cams are synchronized to provide even release force, then shooting accuracy is improved, but normal wear and thermal effects cause desynchronization over time
Solution Approach 1:
The patent incorporates adjustment mechanisms that allow the upper and lower cam assemblies to be manually synchronized after the bow has been assembled. The cam assemblies can be adjusted relative to each other to compensate for wear and thermal effects, ensuring that the release force remains evenly distributed to both ends of the bowstring. This feedback capability maintains shooting accuracy over the service life of the bow by allowing users to realign the cam assemblies when desynchronization occurs.
3Device complexity
If dual-purpose cam modules are used to reduce components, then device complexity is reduced, but alignment precision between planes must be maintained to prevent twisting
Solution Approach 1:
The patent employs dual-purpose cam modules that combine multiple functions within a single component. Each cam module serves as both the power cord take-up mechanism and the power cord let-out mechanism, reducing the total number of separate components needed in the system. This merging is achieved by designing the cam module with appropriate geometry and routing that allows it to perform both functions while maintaining proper alignment between the first plane (bowstring pulley) and the second plane (cam assembly), thereby preventing twisting effects despite the reduced component count.
Data Source
AI summary
A compound archery bow that includes a compound bow frame having a rigid handle section with rearwardly-projecting upper and lower flexible limbs, an upper cam assembly rotatably supported at the free end of the upper flexible limb, and a lower cam assembly rotatably supported at a free end of the lower flexible limb. The upper cam assembly includes an upper bowstring pulley having an upper bowstring let-out track, a first power cord take-up track, and a second power cord let-out track, while the lower cam assembly includes a lower bowstring pulley having a lower bowstring let-out track, a second power cord take-up track, and a first power cord let-out track. The upper and lower bowstring let-out tracks are aligned in a first bowstring plane, while the first power cord take-up and let-out tracks and the second power cord take-up and let-out tracks are aligned in a second power cords plane.