Crossbow Asymmetrical Limb Axle Assembly
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Solution Overview
Problem
Conventional crossbow designs face challenges in efficiently storing and releasing energy to propel arrows, particularly in minimizing vertical rebound forces and optimizing energy transfer mechanisms.
Innovation Solution
The crossbow assembly employs two pairs of vertically aligned limbs with opposing directional forces, connected via axle assemblies and limb cables, which store energy by winding limb cables around an axle shaft and release it to propel arrows through a mechanism involving axle pulleys and a bowstring system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional crossbow designs use traditional limb arrangements, then the structure is simpler, but vertical rebound forces are not minimized and energy transfer is less efficient
Solution Approach 1:
The patent employs an asymmetric limb arrangement where limbs are positioned at different heights (first pair at first height, second pair at second height) rather than symmetrically. This asymmetric configuration creates opposing directional forces that cancel vertical rebound forces, directly addressing the harmful factors while maintaining manageable device complexity through systematic asymmetry.
Solution Approach 2:
The invention transitions from traditional single-plane limb arrangements to a multi-dimensional configuration with limbs distributed at different heights. By adding the vertical dimension to the limb arrangement (first height and second height), the system creates three-dimensional force vectors that oppose and neutralize vertical rebound forces, effectively solving the problem of harmful vertical forces.
2Ease of manufacture
If conventional crossbow designs use simple energy storage mechanisms, then the device is easier to manufacture, but energy transfer efficiency to propel arrows is reduced
Solution Approach 1:
The patent introduces axle assemblies as intermediary components between the limbs and the bowstring. These axle assemblies incorporate pulleys that act as mediators to efficiently transfer energy from the flexing limbs to the bowstring and ultimately to the arrow. This intermediary mechanism maintains ease of manufacture by using simple mechanical components while significantly improving energy transfer efficiency through the pulley system.
Solution Approach 2:
The invention changes the mechanical parameters of the energy storage and transfer system by introducing axles with pulleys at specific positions. This parameter change allows for optimized force distribution and energy transfer angles, improving the efficiency of energy conversion from potential energy in limbs to kinetic energy in the arrow, while the components remain manufacturable with standard machining processes.
3Power
If the crossbow uses a single pair of limbs, then the structure is simpler, but energy storage and transfer capability is reduced
Solution Approach 1:
The patent segments the limb system into two distinct pairs of limbs positioned at different heights. This segmentation allows each pair to contribute independently to energy storage while their combined action provides superior energy storage capability. The segmentation is managed through systematic arrangement (first pair at first height, second pair at second height) that prevents excessive complexity by maintaining clear functional separation.
Solution Approach 2:
The invention merges the functionality of multiple limb pairs into a unified energy storage system. By combining the energy storage contribution of the first pair of limbs with the second pair of limbs, the system achieves enhanced total energy storage capability. The merging is facilitated by the coordinated arrangement of all four limbs working together through the axle assembly, creating a synergistic effect that increases power without proportionally increasing complexity.
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 effectively minimizes vertical rebound forces and optimizes energy transfer, ensuring consistent and efficient arrow propulsion by converting stored limb energy into kinetic energy.
Implementation Method 1
As the axle assembly is turned it wraps the limb cables around the axle shaft, drawing the limb tips vertically together to store energy
Implementation Method 2
A pair of axle pulleys are arranged in vertical planes. The crossbow includes a bowstring with opposing ends having one end connected to each axle pulley
Data Source
AI summary
A crossbow assembly uses an arrangement with two pairs of limbs, with one pair of opposing limbs on each side of the stock. The two limbs within each pair are arranged in opposition to each other in a vertical plane. The limb tips are each connected to an axle assembly with respective limb cables. The axle has a pair of axle pulleys at opposing ends. A bowstring has opposing ends connected to each axle pulley. The bowstring extends forward from each axle pulley and extends across the stock, passing between two bowstring pulleys. The middle of the bowstring forms the nock point.