Multi-Speed Gear Train With Shifting Ring Gear for Cordless Ratchets
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Solution Overview
Problem
Current cordless ratchet tools operate with a single speed and gear ratio, limiting users' ability to adjust between torque and speed, restricting their versatility in removing stubborn fasteners and subsequently removing them quickly.
Innovation Solution
A multi-speed gear train with a 2-stage gearbox using a planetary gearset and shifting ring gear, allowing users to selectively change the output speed and torque by toggling between different gear ratios, enabling high torque for loosening difficult fasteners and high speed for quick removal once the fastener is loosened.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single gear ratio is used in cordless ratchet tools, then the tool can produce maximum output torque, but the user cannot adjust between speed and torque, limiting versatility
Solution Approach 1:
The patent implements a multi-speed gear train with a shifting mechanism that allows the ring gear to move between different positions, dynamically changing the gear ratio. This enables the tool to switch between high torque mode (ring gear in first position) and high speed mode (ring gear in second position), resolving the contradiction between fixed torque output and needed adaptability
Solution Approach 2:
The invention changes the gear ratio parameter by moving the ring gear between different engagement positions with the planetary gearset. This parameter change allows the tool to provide multiple speed-torque combinations, enabling users to optimize performance for different fastener removal scenarios while maintaining maximum torque capability when needed
2Device complexity
If a single speed gear train is used, then the tool structure remains simple, but the user cannot switch between high torque for loosening fasteners and high speed for quick removal
Solution Approach 1:
The gear train is segmented into multiple stages with distinct functions: a planetary gearset for torque multiplication and a gear train with a shifting ring gear for speed adjustment. This segmentation allows each component to specialize in one aspect (torque or speed) while working together, providing both high torque and high speed capabilities without excessive overall complexity
Solution Approach 2:
The multi-speed gear train serves multiple functions: it provides maximum torque for loosening stubborn fasteners, high speed for quick removal of already-loosened fasteners, and intermediate settings for various operating conditions. This multi-functionality increases productivity by allowing the single tool to handle diverse fastener removal scenarios efficiently
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
Enables users to generate high torque for loosening difficult fasteners at lower speeds and switch to high speed for quicker removal, enhancing the tool's versatility and operational efficiency.
Implementation Method 1
a planetary gearset with a shifting ring gear coupled to a set of compound gears that allows a user to selectively change the output speed and/or torque
Data Source
AI summary
A power tool, such as a cordless power ratchet, with a multi-speed gear train is described. A gearbox may use a planetary gearset with a shifting ring gear coupled with a set of compound gears that allows the user to change the output speed of the tool by altering the total gear ratio of the gearbox. A first stage may include a planetary gearset with a shifting ring gear. A second stage may include a set of compound gears whose output connects to the tool's driving mechanism. The exemplary gearbox may allow the user more control over the output during tool operation. A cordless ratchet with a multi-speed geartrain may allow the user to generate high levels of torque to remove a fastener (i.e., making the tool operate at a lower speed), and allow the user to remove the fastener quicker by increasing the speed of the tool.