Crossbow Arrow Assembly With Reverse-Draw Dry-Fire Lockout
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional crossbows are limited by a power stroke of about 270 degrees due to the contact of power cables with power cable take-up journals, restricting the length of the power stroke and requiring larger pulleys, which results in a less usable bow.
Innovation Solution
The implementation of a reverse draw configuration with helical journals that displace power cables away from string guides, allowing for more than 360 degrees of rotation, increasing the power stroke by 25% to 40% without enlarging the pulleys, and incorporating a catch mechanism with a dry fire lockout system to prevent dry firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If power cables contact power cable take-up journals in conventional configuration, then the bow structure remains compact, but the power stroke is limited to about 270 degrees
Solution Approach 1:
The patent inverts the conventional arrangement by positioning the draw string on the down-range side of the string guides rather than the traditional up-range side. This reverse draw configuration allows the draw string to unroll between the string guides toward the user, enabling greater than 360 degrees of rotation and significantly increasing the power stroke length without requiring larger pulleys or more complex bow structures.
2Length of moving object
If pulley diameter is increased to allow greater rotation, then power stroke length increases, but the bow becomes larger and less usable
Solution Approach 1:
By inverting the draw string position to the down-range side, the patent achieves greater rotation angles without increasing pulley diameter. The reverse draw configuration allows the draw string to unroll efficiently between the string guides, providing extended power stroke while maintaining compact pulley sizes and overall bow dimensions.
Solution Approach 2:
The patent utilizes the spatial dimension between the string guides more effectively by positioning the draw string to unroll in the gap between them. This dimensional utilization allows the draw string to achieve greater effective length and rotation without requiring larger pulleys, thereby increasing power stroke while maintaining compact bow size.
3Productivity
If draw string is positioned on up-range side in conventional configuration, then bow structure remains simple, but power stroke is limited
Solution Approach 1:
The patent inverts the conventional draw string positioning from the up-range side to the down-range side of the string guides. This reversal enables the draw string to unroll between the string guides toward the user, significantly increasing power stroke efficiency and length while maintaining relatively simple string guide configuration and avoiding the need for larger or more complex pulley systems.
Data Source
AI summary
A method of engaging an arrow with an anti-dry fire system on a crossbow and an arrow assembly for crossbow that engages the anti-dry fire system behind the draw string. Matched weight arrows having lighted and non-lighted nocks are also disclosed.