Crossbow Limb Vibration Damping via Elastomer Coating
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Solution Overview
Problem
Crossbow limbs made of glass fiber or carbon fiber experience strength degradation and noise generation due to vibration, leading to potential breakage and reduced lifespan.
Innovation Solution
A protection coat with greater flexibility than the limb, made from thermoplastic or thermoset elastomers, is mounted on the crossbow limb to absorb vibration and reduce amplitude, connected via injection molding or hot press molding, ensuring the limb's energy storage and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass fiber or carbon fiber is used for crossbow limbs, then lightness and strength are improved, but vibration resistance and service life deteriorate
Solution Approach 1:
The patent applies composite materials by combining glass fiber or carbon fiber (for strength and lightness) with a rubber protection coat (for vibration absorption). This multi-material composite structure resolves the contradiction by allowing each material to contribute its superior properties: the fiber provides structural strength while the rubber layer dampens vibrations, thereby improving both strength and vibration resistance simultaneously.
2Use of energy by moving object
If fiber limbs are used for crossbow, then elasticity and energy storage are improved, but susceptibility to cracking and breakage worsens
Solution Approach 1:
The patent implements beforehand cushioning by pre-installing a rubber protection coat on the fiber limb before cracks can form. This protective layer acts as a cushion that absorbs vibrations and stress concentrations during the limbing action, preventing the initiation and propagation of cracks. The rubber coat is designed to deform with the limb during energy storage and release, protecting the fiber structure from harmful stress.
3Strength
If rigid protection is applied to limb, then breakage resistance is improved, but flexibility and energy storage capability worsen
Solution Approach 1:
The patent applies parameter changes by selecting rubber material with specific elastic properties for the protection coat. The rubber material is chosen to have appropriate elasticity and flexibility parameters that allow it to deform with the limb during the energy storage phase, then return to its original shape during energy release. This parameter optimization ensures the protection coat provides breakage resistance while maintaining the limb's energy storage and release capabilities.
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 protection coat effectively reduces vibration amplitude, preventing limb breakage and extending its lifespan while minimizing noise, thus enhancing the crossbow's operational quality.
Implementation Method 1
The protection coat absorbs vibration from the limb when the limb bounces back so as to protect the limb from being broken by reducing the vibration amplitude
Implementation Method 2
The flexibility of the protection coat greater than the flexibility of the limb. The protection coat is deformed with the limb when the limb is deformed
Data Source
AI summary
A protection device of a crossbow includes a protection coat that is mounted to the limb. The flexibility of the protection coat greater than the flexibility of the limb so that the protection coat is deformed with the limb when the limb is deformed. The protection coat absorbs vibration from the limb when the limb bounces back so as to protect the limb from being broken by reducing the vibration amplitude.