Crossbow Barrel Weight Center Stabilization
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Solution Overview
Problem
Conventional crossbows face issues with instability due to uneven weight distribution, leading to precision problems and noise caused by arrow expansion in the barrel groove, and the use of metal barrels increases cost and weight.
Innovation Solution
A crossbow assembly design featuring a barrel with a recess and upper and lower portions of different thicknesses, where the bow unit is secured with bolts through threaded holes, and the upper portion is made of metal for strength and the lower portion of plastic for reduced weight, maintaining a stable weight center and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the barrel is made of metal to obtain a secure and strong structure, then the strength is improved, but the weight and cost increase
Solution Approach 1:
The barrel is designed with different thicknesses at different locations: the first portion (near the bow unit) has a greater thickness to provide strength where vibration and stress occur, while the second portion (extending beyond the body) has a smaller thickness to reduce weight. This local differentiation of material properties resolves the contradiction between overall strength and weight reduction.
2Device complexity
If the bow unit weight is supported on the lower portion of the barrel, then the structure is simplified, but the precision of shooting deteriorates due to tilting
Solution Approach 1:
The upper portion of the barrel is designed with greater thickness and extends into the body to provide counterbalancing weight that offsets the weight of the bow unit supported on the lower portion. This creates a balanced weight distribution that prevents tilting and maintains shooting precision while keeping the structure relatively simple.
3Ease of operation
If the arrow groove in the barrel is used repeatedly, then the convenience of use is maintained, but noise is generated due to permanent gaps formed by arrow expansion
Solution Approach 1:
The barrel groove dimensions are designed with appropriate clearance and elasticity considerations to accommodate arrow expansion during repeated use without forming permanent gaps. The material properties and groove geometry are optimized to maintain tight fit even after multiple shots, preventing noise generation while allowing continuous convenient use.
Data Source
AI summary
A crossbow assembly includes a body having an insertion hole and a retention member protrudes from the insertion hole. A barrel has a first end inserted into the insertion hole and a second end of the barrel extends beyond the insertion hole. A recess is defined in the top of the second end of the barrel. An upper portion is connected to the top of the barrel. A lower portion is formed at the underside of the barrel. The thickness of the upper portion is smaller than or equal to a half of that of the lower portion. A bow unit is connected to the second end of the upper portion and includes a riser, two limbs and two cam units. The upper portion is connected to two plates extending from a slot in the riser by two bolts. The crossbow assembly has a stable weight center.