Internal Acceleration System for Powered Bow Leverage
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Solution Overview
Problem
Conventional crossbow designs are limited in firing power due to the maximum tension of the bow string, restricting projectile launch speeds to around 400 feet/second, and suffer from increased stress and reduced lifespan due to required force.
Innovation Solution
An internal acceleration system utilizing a launch string leveraged by the main power string, with a carriage and pulley mechanism within the bow's fore-end, allowing for increased leverage and acceleration of the projectile without relying on external springs or gas cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional bow string tension is used to launch projectiles, then the bow structure remains simple, but the projectile launch speed is limited to around 400 feet/second
Solution Approach 1:
The patent introduces a launch string as an intermediary element between the main power string and the projectile. The main power string does not directly launch the projectile but instead pulls the launch string, which then propels the projectile. This intermediary mechanism enables higher launch speeds (600+ feet/second) while maintaining a relatively simple bow structure, as the complexity is contained within the internal acceleration system rather than the bow limbs themselves.
2Speed
If higher draw weight is used to increase launch speed, then projectile speed increases, but stress on the bow increases and lifespan decreases
Solution Approach 1:
The patent segments the power transmission function into two separate strings: the main power string that stores and releases energy from bow limb tension, and the launch string that directly propels the projectile. This segmentation allows the bow limbs to operate at lower, less stressful tensions while still achieving high projectile speeds through the leveraged acceleration of the launch string by the carriage mechanism.
3Power
If direct bow string launch is used, then the bow design remains traditional and simple, but leverage for projectile acceleration is limited
Solution Approach 1:
The patent implements a nested structure where the acceleration mechanism (comprising the launch string and carriage) is contained within the bow's fore-end. The main power string passes through the carriage, which moves along a track within the fore-end, pulling the launch string in a leveraged fashion. This nested design provides double or triple leverage for projectile acceleration while keeping the internal system compact and integrated within the traditional bow structure.
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
Achieves projectile launch speeds of 600 feet/second or greater, reducing the necessary draw weight and stress on the bow, thereby prolonging its useful life and enabling double or triple the leverage for faster arrow speeds.
Implementation Method 1
The main bow string is operatively coupled to the launch string for propelling the launch string in leveraged fashion
Implementation Method 2
Movement of the main bow string causes acceleration of the launch string, which, in turn, causes the projectile to be launched from the upper surface of the body portion of the bow with increased velocity
Data Source
AI summary
A leveraged bow for launching a projectile, the bow having a stock, a butt region and a grip region, and a fore-end supporting a pair of bow arms. The fore-end includes a top surface for receiving and supporting the projectile and a carriage assembly slidably mounted with an interior region of the fore-end. A main bow power string is coupled to the carriage. The carriage also has a launch string associated therewith which is powered by the movement of the main bow power string. A trigger and latch are used to release the bow power string and, in turn, the launch string to leverage the velocity of the arrow being propelled by the bow.