Integrated Crossbow Cocking Device with Rotating Shaft
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Solution Overview
Problem
Users with smaller stature or physical limitations face difficulties in drawing back the bowstring of a crossbow due to the required force needed to store energy for propelling arrows, as existing cocking devices do not provide adequate assistance.
Innovation Solution
An integrated cocking device with a shaft member, base plates, rope members, and handles is designed to be installed on the crossbow, allowing users to draw the bowstring more easily by rotating the shaft member and adjusting the effective length of the rope members, which are then engaged with the bowstring to be retained by the trigger mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional crossbow without assistance device is used, then the structure is simple, but users with smaller stature or physical limitations cannot exert sufficient force to draw back the bowstring
Solution Approach 1:
The cocking device is nested within the crossbow structure, with the shaft member fitting through the device aperture in the stock member. The base plates are positioned on opposite sides of the stock member, creating a compact integrated design that reduces overall complexity while providing mechanical assistance for drawing the bowstring.
Solution Approach 2:
The shaft member is designed to be rotatable within the device aperture, allowing dynamic adjustment of the rope members' effective length. This rotational mechanism enables the device to adapt to different drawing positions and provides mechanical advantage throughout the drawing motion, improving ease of operation without requiring a complex fixed structure.
2Ease of operation
If the rope members are made longer to provide greater mechanical advantage, then the ease of drawing bowstring improves, but the device size and complexity increase
Solution Approach 1:
The effective length of the rope members is made dynamically adjustable through the rotatable shaft member. As the shaft rotates during the drawing motion, the rope members are progressively unwound or rewound, providing variable mechanical advantage that is optimized at each stage of the drawing motion without requiring excessively long fixed rope members.
Solution Approach 2:
The mechanical advantage provided by the rope members is changed dynamically by rotating the shaft member, which alters the effective length and angle of the rope members. This parameter change allows the device to provide optimal mechanical assistance throughout the drawing motion while maintaining a compact overall size.
3Adaptability or versatility
If the cocking device is made removable for flexibility, then the adaptability improves, but the reliability and stability during operation may decrease
Solution Approach 1:
The cocking device is segmented into separate components (shaft member, base plates, rope members, handle) that can be independently assembled and removed. The shaft member with its rotatable mechanism can be installed or removed through the device aperture, providing flexibility while maintaining stability during operation through proper engagement with the crossbow structure.
Solution Approach 2:
The cocking device is designed as a universal accessory that can be installed on various crossbow models through the standardized device aperture. The rotatable shaft mechanism serves multiple functions including providing mechanical advantage, adjusting rope length, and engaging with the bowstring, making the removable device equally reliable for different applications.
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 cocking device facilitates easier drawing and storing of energy in the crossbow limbs, enabling users to propel arrows effectively without excessive force, enhancing usability for a broader range of operators.
Implementation Method 1
a first rope member operatively connected to the shaft member between the first base plate and the first side plate; a second rope member operatively connected to the shaft member between the second base plate and the second side plate, wherein the rotation of the shaft member causes a change in an effective length of the first and second rope members
Implementation Method 2
a shaft member, wherein the shaft member is rotatably received through the first and second base plates; a first side plate connected to a first end of the shaft member; a second side plate connected to a second end of the shaft member, wherein the rotation of the shaft member causes a corresponding rotation of the first and second side plates
Implementation Method 3
The drawing of the bowstring causes potential energy to be stored in the limbs of the crossbow. The bowstring can be drawn rearward and retained by the trigger mechanism
Data Source
AI summary
A cocking device for drawing the bowstring of a crossbow that can be selectively installed on an existing crossbow. The cocking device comprises a shape designed to prevent the cocking device from being improperly installed.