Portable Crossbow Cocking Device Balanced Tension
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Solution Overview
Problem
Conventional crossbow cocking devices are often large, heavy, cumbersome, and fail to ensure balanced tension of the bowstring, making it difficult for users with limited physical strength to draw and maintain the bowstring, which affects accuracy and safety.
Innovation Solution
A portable cocking device comprising a first and second handle, a housing, a flexible member, and hook members that allow for balanced drawing of the bowstring by distributing the force evenly, enabling easier cocking and reducing the mechanical advantage required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the stiffness of the bow limbs is increased to increase projectile speed and accuracy, then the projectile propulsion speed and accuracy are improved, but the force required to draw the bowstring increases significantly
Solution Approach 1:
The patent introduces a stirrup as an intermediary device between the user and the crossbow. The stirrup allows the user to leverage their body weight through a fulcrum point, providing mechanical advantage to overcome the high bowstring pull weight without requiring direct manual force application. This mediator enables users with limited physical strength to cock high-stiffness crossbows.
Solution Approach 2:
The cocking process is segmented into distinct phases: positioning the stirrup, applying body weight, and releasing the trigger. The stirrup itself is a segmented device with a fulcrum point that separates the application of force from the point of action on the bowstring, allowing independent optimization of each function.
2Ease of operation
If conventional manual crank winch devices or leverage-type cocking devices are used to reduce the force required to draw the bowstring, then the ease of operation is improved, but the device complexity and weight increase
Solution Approach 1:
The patent extracts the essential mechanical advantage function from complex crank winch mechanisms and implements it through a simple stirrup and fulcrum system. By removing unnecessary components (gears, cranks, winches) and retaining only the core leverage principle, the device achieves ease of operation with minimal complexity.
Solution Approach 2:
The stirrup mechanism is self-contained and requires no additional power source, controls, or complex operating procedures. The user simply positions their body weight on the stirrup, and the mechanical advantage is automatically provided through the fulcrum geometry, eliminating the need for manual cranking or complex lever manipulation.
3Ease of operation
If a stirrup is used to support the crossbow for cocking by applying body weight, then the ease of operation is improved, but the ability to ensure balanced tension of the limbs is compromised
Solution Approach 1:
The patent introduces asymmetric alignment features including a tapered guide surface on the stirrup and a corresponding alignment ridge on the crossbow stock. These asymmetric elements guide the bowstring and limbs into proper alignment during the cocking process, ensuring balanced tension distribution across both limbs despite the asymmetric body weight application.
Solution Approach 2:
The guide surface and alignment features provide tactile feedback to the user during positioning, indicating when the crossbow is properly aligned for balanced cocking. The mechanical geometry itself provides feedback through the engagement of the alignment ridge with the guide surface, ensuring correct orientation before the user applies body weight.
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 device provides a compact, lightweight, cost-effective solution that allows for balanced bowstring tension, reducing the effort needed to draw the bowstring and ensuring equalized force upon release, enhancing user safety and accuracy.
Implementation Method 1
The first and second hook members may be positioned between the first and second handles. The first and second attachment assemblies may be adapted to receive at least a portion of a bowstring of a crossbow and the first and second coupling assemblies may be adapted to at least partially enable the movement of the first and second hook members along at least a portion of the flexible member.
Data Source
AI summary
A portable device for drawing the bowstring of a crossbow. The cocking device may be designed to prevent the uneven drawing of the crossbow and may eliminate the complex installation process typically required to retro-fit an existing crossbow with known cocking devices.