Crossbow Trigger Assembly with Concave String Hook
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Solution Overview
Problem
Conventional crossbow triggers experience high frictional resistance due to plane stop and engagement faces, making it difficult to pull the trigger effectively.
Innovation Solution
A concave portion is formed on the engagement face of the string hook member between its first and second periphery, reducing frictional resistance without compromising the structural strength of the string hook member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If plane stop face and engagement face are used in the trigger assembly, then the structural strength is maintained, but the frictional resistance increases making trigger operation difficult
Solution Approach 1:
The patent applies curvature by forming a concave portion on the engagement face of the string hook member. This concave surface replaces the conventional plane engagement face, creating a curved interface between the stop face and engagement face. The curved surface reduces the contact area and distributes the frictional force, thereby reducing overall frictional resistance and making trigger operation easier while maintaining structural strength.
2Force
If the engagement face area is reduced to lower friction, then the structural strength of the string hook member may be compromised
Solution Approach 1:
The patent applies local quality by creating a concave portion only on the engagement face where friction occurs, while maintaining the overall structural integrity of the string hook member. The concave portion is strategically positioned to reduce frictional contact area without compromising the structural strength of the member. This localized modification allows the engagement face to have different properties (reduced friction) in the contact region while maintaining strength in the structural regions.
Data Source
AI summary
In trigger labor-saving structure of a crossbow, the crossbow includes a body, an arcuate limb, and a trigger assembly. The limb is mounted adjacent to a front end of the body and intersects with the body, and the limb includes a bowstring. The trigger assembly includes: a trigger seat arranged on the body, a trigger partially accommodated in the trigger seat and downward extending out of the trigger seat, with the trigger having a stop face; a string hook member housed in the trigger seat and including an engagement face corresponding to the stop face; and at least one concave portion formed on the engagement face of the string hook member and defined between a first periphery and a second periphery of the engagement face. Thus, frictional resistance between the stop face and the engagement face reduces.