Crossbow Worm Gear Spool for Controlled Cocking and De-Cocking
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Solution Overview
Problem
Existing crossbows lack an integral cocking and de-cocking mechanism utilizing a worm gear, which complicates the process of loading and unloading the bowstring, and often require additional devices like pawls or clutches to manage spool rotation.
Innovation Solution
A crossbow with a built-in cocking mechanism that integrates a worm gear with a spool, optionally coupled with a removable motor gearbox assembly, allowing for controlled rotation of the spool using a worm gear drive, eliminating the need for secondary devices like pawls or clutches by using a clutch assembly and motor control switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a traditional spool mechanism is used for cocking and de-cocking, then the structure is simple, but additional devices like pawls or clutches are required to control spool rotation
Solution Approach 1:
The patent replaces traditional mechanical control devices (pawls, clutches) with a worm gear mechanism that inherently provides controlled rotation and self-locking. The worm gear's threaded engagement with the spool creates a mechanical system where rotation is naturally constrained in one direction while allowing controlled rotation in the other direction, eliminating the need for separate control devices.
Solution Approach 2:
The worm gear mechanism provides self-service by automatically controlling the spool's rotation through its inherent mechanical properties. The worm gear's geometry creates self-locking behavior that prevents reverse rotation without requiring external control devices, making the system self-regulating and reducing overall complexity.
2Extent of automation
If manual cocking operation is used, then the device structure is simple, but the cocking process requires manual effort and time
Solution Approach 1:
The patent implements a removable motor gearbox assembly that can be dynamically attached or detached from the worm gear mechanism. This dynamic configuration allows the system to transition between manual and automated operation modes, providing flexibility in automation extent while managing device complexity through optional rather than mandatory motorized components.
Solution Approach 2:
The motor gearbox assembly serves multiple functions: it can be installed to provide automated cocking and de-cocking operations, or removed to allow manual operation. This multi-functional design enables the same crossbow platform to adapt to different user needs and operational requirements without requiring separate systems.
3Productivity
If a removable motor gearbox assembly is added, then automated cocking is achieved, but the device structure becomes more complex
Solution Approach 1:
The removable motor gearbox assembly enables dynamic configuration of the cocking system. Users can install the motor for high-speed automated cocking when productivity is prioritized, or remove it for simpler manual operation when portability or maintenance is prioritized. This dynamic adaptability resolves the contradiction by allowing productivity enhancement without permanently increasing device 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
The solution provides a seamless and efficient cocking and de-cocking process, allowing for precise control over the string retention device, reducing the complexity of manual operation and enhancing safety by eliminating the need for additional devices.
Implementation Method 1
A worm gear drive is provided having an external drive receiver and an internal worm gear drive assembly. The worm gear drive may be operably coupled to a spool, or may be integrated with the spool.
Implementation Method 2
In a second embodiment, the motor gearbox assembly has a solenoid select-ably extending the drive gear and output shaft to an engaged position, and retracting the drive gear and output shaft to a disengaged position.
Data Source
AI summary
A crossbow with a cocking mechanism having a worm gear assembly coupled with a spool, that may also be utilized with an optional built in, removable motor gearbox assembly and power source. The motor gearbox assembly may or may not have a clutch assembly, when rotational force reaches a predetermined amount, rotation of the drive shaft stopses. Switches may be provided to start, stop, and reverse the direction of rotation of the motor gearbox assembly, as well as switches and or circuits that may control operation of the motor gear set.