Crossbow Winding System with Interconnects for Narrow Width
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Solution Overview
Problem
Conventional crossbow designs face challenges in achieving a narrow width while maintaining high power and performance, often requiring complex limb designs and additional mass at the free ends due to the need for wheels or cams that can withstand significant forces, leading to imbalance and increased complexity.
Innovation Solution
The crossbow design incorporates a bow system with a riser positioning first and second limbs on either side of the barrel, featuring a first and second winding system with interconnects that transfer forces between limb and arrow string winders, allowing for efficient energy storage and release, reducing unsprung mass, and maintaining precise positional relationships without the need for wheels or cams on the limbs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If wheels or cams are mounted at the free ends of limbs to achieve narrow crossbow design, then the crossbow width is reduced, but the device complexity and mass increase due to additional components needed to withstand high loads and forces
Solution Approach 1:
The patent removes the wheels or cams from the limb design entirely, extracting the problematic components that caused complexity and mass issues. Instead of mounting wheels at the free ends of limbs, the invention uses a different mechanical arrangement where the string directly engages the limbs without intermediate wheel components, thereby achieving narrow width without the associated complexity penalties
Solution Approach 2:
Rather than using wheels or cams to achieve the desired narrow profile, the invention inverts the approach by having the string directly contact and engage the limbs in a configuration that naturally achieves the narrow width without additional components. This reversal of the conventional wheel-mounted approach eliminates the need for complex wheel mountings while maintaining the compact profile
2Area of moving object
If wheels or cams are mounted at the free ends of limbs, then the crossbow can achieve a compact design, but the reliability decreases due to exposure to shock, vibration, and incidental contact
Solution Approach 1:
The patent extracts the vulnerable wheel components from the system, eliminating their exposure to shock, vibration, and incidental contact. By removing the wheels entirely and using direct string-limb engagement, the invention prevents the reliability issues that would otherwise plague wheel-mounted designs in harsh field conditions
Solution Approach 2:
The limbs themselves serve the function of directly engaging the string without requiring separate wheel components. The limbs are designed to work with the string in a way that achieves the compact profile while the limbs' inherent structural properties provide the necessary durability and resistance to environmental stresses
3Area of moving object
If additional mass is added to the free ends of limbs for wheel mountings, then the crossbow achieves a narrow width, but the manufacturing precision and balance are compromised due to imbalance relative to the limb center plane
Solution Approach 1:
The patent removes the additional mass components (wheels and their mountings) from the limb free ends, thereby eliminating the imbalance problem. Without these extra components, the limbs maintain their natural balance and symmetry, achieving the narrow width without compromising manufacturing precision or creating rotational imbalance
Solution Approach 2:
The invention employs asymmetric string routing and limb engagement geometry that achieves the narrow profile through the arrangement of existing components rather than adding asymmetric mass. The string contacts the limbs in a configuration that creates the compact width while maintaining symmetry and balance of the limb assembly
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
This design achieves a more compact and powerful crossbow with reduced complexity, improved accuracy, and increased energy transfer to the arrow, while minimizing unsprung mass and friction, enhancing portability and maneuverability.
Implementation Method 1
This bends the limbs storing potential energy in the limbs. When the trigger is activated the potential energy in the limbs is converted into kinetic energy that drives the string and arrow along the barrel to fire the arrow.
Implementation Method 2
a first interconnect between the first limb string winder and the first arrow string winder... transferring at least a portion of a first force urging rotation of the first limb string winder to urge rotation of the first arrow string winder
Data Source
AI summary
Crossbows are provided having a barrel with one limb and one winding system mounted to each of two opposite sides of the barrel. Each winding system has a limb string connected to one of the limbs and a limb cam about which the limb string can be wound. The limb cams are connected to and positioned apart from arrow string cams by respective interconnects and an arrow string extends across the barrel from an arrow string cam on one side of the barrel to an arrow string cam on the other side of the barrel. The limbs provide first forces urging the limb strings to unwind from the limb cams and the interconnects receive the first forces and convey a second forces to the arrow cams urging the arrow cams to rotate so as to wind the arrow strings onto the arrow cams. The arrow string is drawn against such urging.