Crossbow Worm Gear Spool Coupling for Easier Cocking
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Solution Overview
Problem
Prior art crossbows lack a feature that allows de-coupling of the worm gear wheel from the shaft, making it difficult to cock the crossbow efficiently as the spools require rotation of the worm gear, necessitating additional devices like pawls or clutches to cease rotation.
Innovation Solution
A crossbow with a built-in cocking mechanism that includes a worm gear coupled with a spool and an optional removable motor gearbox assembly, allowing selective de-coupling of the worm gear from the shaft, enabling free rotation of the spools and eliminating the need for secondary devices to stop spool rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the worm gear wheel is permanently coupled to the shaft, then the crossbow maintains structural simplicity, but the spools cannot rotate freely making cocking difficult and requiring additional devices like pawls or clutches
Solution Approach 1:
The patent applies the dynamics principle by making the coupling between the worm gear wheel and shaft changeable rather than fixed. The shaft can be selectively coupled to either the worm gear wheel or the spools, allowing the system to dynamically adjust its configuration based on operational needs. This enables free rotation of spools during cocking while maintaining structural integrity during firing.
Solution Approach 2:
The patent segments the drive train into separate functional modules: the worm gear wheel, the shaft, and the spools are distinct components that can be independently coupled or decoupled. This segmentation allows the shaft to be selectively engaged with different components, enabling the spools to rotate freely without the worm gear during cocking operations.
2Device complexity
If the spools are permanently coupled to the worm gear, then the cocking mechanism is structurally simple, but additional devices like pawls or clutches are required to stop spool rotation
Solution Approach 1:
The dynamic coupling mechanism allows the shaft to be selectively engaged or disengaged from the spools. When disengaged, the spools can rotate freely without requiring pawls or clutches to control their rotation. This dynamic reconfiguration simplifies the overall device structure while improving ease of operation.
Solution Approach 2:
The patent extracts the secondary control devices (pawls, clutches) from the system by enabling direct free rotation of the spools through decoupling. The shaft can be removed from the worm gear wheel connection, allowing spools to rotate independently without requiring additional stopping mechanisms.
3Strength
If the shaft is fixed to rotate the worm gear to unwind spools, then the mechanism maintains structural integrity, but user effort increases and cocking becomes difficult
Solution Approach 1:
The patent implements dynamic coupling that allows the shaft to be disengaged from the worm gear wheel during cocking operations. This enables the spools to rotate freely without requiring the shaft to rotate the worm gear, significantly reducing user effort while maintaining structural integrity when engaged for firing.
Solution Approach 2:
By segmenting the coupling mechanism, the patent allows independent rotation of spools from the worm gear wheel. The shaft serves as a selective connector that can be engaged or disengaged, enabling free spool rotation during cocking while maintaining structural strength when the full mechanism is engaged for crossbow operation.
Data Source
AI summary
A worm gear assembly wherein the worm wheel gear is axially coupled with a shaft and a coupler. The coupler may be selectable from a first position locked with the wheel gear and the shaft to a second position unlocked with the wheel gear and the shaft. The coupler may be interactive with the worm wheel gear, or another component coupled with the shaft.