Gear-Driven Crossbow Cocking Mechanism for Reduced Draw Weight
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Solution Overview
Problem
Crossbows are bulky, difficult to cock, and cause arm fatigue due to their large size and weight, making them inconvenient for hunting and competition events, especially for archers with limited strength.
Innovation Solution
A compact crossbow design featuring a stock with a rearward-facing butt, a body with a trigger housing and limb mount, and moveable limbs coupled to an electrical energizer, allowing for easy cocking and reduced arm fatigue through a power-assisted draw system that uses an electrical power source to generate spring force for projectile launch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional crossbow design with large limbs is used, then appropriate draw weight is achieved, but crossbow size and weight increase causing arm fatigue and handling difficulties
Solution Approach 1:
The patent replaces the traditional mechanical spring-based draw system with an electrical motor-driven system. The motor (145) drives a gear mechanism (130, 135) that winds the bowstring onto a drum (125), eliminating the need for large heavy springs while achieving the required draw weight through electrical power assistance.
Solution Approach 2:
The crossbow uses a periodic cocking mechanism where the motor intermittently winds the bowstring onto the drum in discrete steps. Each winding cycle increases the draw weight progressively, allowing the system to achieve high draw weights through repeated periodic action rather than requiring a single large mechanical spring.
2Force
If traditional crossbow design with long limbs is used, then appropriate draw weight is generated, but crossbow length increases complicating use and carrying
Solution Approach 1:
The patent employs dynamic limbs (115, 120) that can change their effective length and configuration during operation. The limbs are moveably coupled to the body (105) and can be adjusted or folded, allowing the crossbow to achieve necessary draw weight when deployed while maintaining a compact form factor for carrying and storage.
Solution Approach 2:
The crossbow design allows the limbs to be positioned or folded in a nested configuration when not in use, reducing the overall length. The limbs can be tucked alongside the body or folded backward, enabling compact storage and easy carrying while maintaining full functionality when deployed for shooting.
3Device complexity
If manual cocking mechanism is used, then crossbow structure remains simple, but cocking becomes difficult especially for archers lacking body strength
Solution Approach 1:
The patent replaces manual mechanical cocking with an electrical motor-driven system. The motor (145) automatically winds the bowstring onto the drum (125) through gear mechanisms (130, 135), eliminating the need for the archer to manually exert force to cock the crossbow, thereby greatly improving ease of operation.
Solution Approach 2:
The crossbow cocks itself automatically through the motor-driven system. Once the archer activates the cocking mechanism, the motor independently performs the cocking action by winding the bowstring onto the drum, without requiring continuous manual intervention or effort from the archer.
4Force
If forward weight distribution is concentrated, then crossbow generates adequate shooting force, but arm fatigue and aiming difficulties increase
Solution Approach 1:
The patent positions the motor (145) and battery pack (140) in the rear portion of the crossbow to counterbalance the weight of the limbs and bowstring assembly at the front. This balanced weight distribution reduces torque on the archer's arm, minimizing fatigue and improving aiming stability while maintaining adequate shooting force through the balanced configuration.
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 design enables a compact, lightweight crossbow that requires less manual strength to cock and reduces arm fatigue, allowing for accurate and efficient shooting without increasing the crossbow's size or weight, enhancing usability and performance.
Implementation Method 1
an electrical power source; and a motion generator operatively coupled to the gear system and powered by the electrical power source
Implementation Method 2
a gear system including a plurality of gears in mesh with one another, the gear system having a gear ratio that amplifies an input force to an output force
Implementation Method 3
a plurality of limbs moveably coupled to the body... Each of the limbs includes... an uncoupled limb end that is positioned forward of the coupled limb end
Data Source
AI summary
An archery limb control system, method and bow are described herein. The archery limb control system, in an embodiment, includes a motion generator configured to be supported by an archery bow, and the system includes one or more flexible lines configured to be coupled to the limbs of the bow. The system also includes a support configured to support the one or more flexible lines, and the system includes a gear coupled to the support.