Cordless Power Tool Torque Limiting Mechanism
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Solution Overview
Problem
Conventional hand-held power tools lack a compact and cost-effective torque-limiting mechanism that efficiently limits torque transmission to prevent overload and ensure reliable operation, often requiring additional components like spring supports or washers.
Innovation Solution
A torque-limiting device utilizing a spring mechanism with disk springs acting on detent mechanisms, which includes rolling elements and a guide device for efficient force transmission, allowing for direct adjustment of maximum torque without intermediate components, thereby simplifying assembly and reducing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional torque-limiting mechanisms are used with spring supports or washers, then torque limitation function is achieved, but device complexity and assembly complexity increase
Solution Approach 1:
The patent combines the spring support function and torque limitation function into a single integrated component. The spring mechanism with disk springs is directly coupled to the detent mechanisms, eliminating the need for separate spring supports or washers. This merging of functions reduces the number of parts and simplifies assembly while maintaining reliable torque limitation.
Solution Approach 2:
The spring mechanism serves multiple functions simultaneously: it provides the limiting force for torque limitation, acts as a mounting structure for the detent mechanisms, and enables the clutch reaction. This multi-functionality eliminates the need for additional specialized components like spring supports or washers, reducing device complexity.
2Reliability
If additional components like spring supports or washers are included, then torque limitation is achieved, but weight and space increase
Solution Approach 1:
The patent extracts and eliminates unnecessary intermediate components such as spring supports or washers from the torque limitation mechanism. By using a simplified spring mechanism with disk springs that directly acts on the detent mechanisms, the design removes redundant parts, reducing both weight and space while maintaining the torque limitation function.
Solution Approach 2:
By merging the spring support function into the spring mechanism itself, the patent eliminates separate support components. The disk springs are directly coupled to the detent mechanisms, creating a compact assembly that reduces overall weight and space requirements compared to conventional designs with multiple separate components.
3Reliability
If conventional torque-limiting devices are used, then torque transmission is limited, but assembly complexity and costs increase
Solution Approach 1:
The patent segments the torque limitation function into discrete detent mechanisms that can be independently positioned and adjusted. Each detent mechanism with its associated spring can be assembled and tested separately, then integrated into the final device. This segmentation simplifies the manufacturing process and reduces assembly complexity compared to conventional integrated designs.
Solution Approach 2:
The patent uses a dynamic spring mechanism with disk springs that can be adjusted to change the torque limitation threshold. The spring mechanism allows for easy adjustment of the clutch reaction point by modifying the spring preload or positioning, enabling flexible manufacturing and assembly without requiring complex fixed-geometry components.
4Reliability
If more components are added to ensure reliable torque limitation, then torque control improves, but the number of parts and costs increase
Solution Approach 1:
The patent merges multiple functions into the spring mechanism with disk springs, which simultaneously provides the limiting force, the mounting structure, and the adjustment mechanism. This consolidation reduces the number of parts needed while maintaining reliable torque control through the integrated design.
Solution Approach 2:
The spring mechanism serves multiple purposes: it provides the elastic force for torque limitation, acts as the mounting structure for detent mechanisms, and enables adjustable clutch reaction. This multi-functionality reduces the total number of parts required compared to conventional designs that use separate components for each function.
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 achieves a space-saving, parts-saving, and reliable torque-limiting mechanism that effectively limits torque transmission, enhancing the tool's durability and operational efficiency while reducing assembly complexity and costs.
Implementation Method 1
a spring mechanism (20) with a first disk spring (22) which acts on at least two detent mechanisms (24, 26) arranged in a circumference direction
Data Source
AI summary
The invention is based on a hand-held power tool, in particular a cordless power tool, having a torque-limiting device that is provided for setting a maximum torque that a motor output is able to transmit to a tool-driving element. A spring mechanism equipped with at least one first disk spring is provided such that the at least one disk spring acts on at least two detent mechanisms arranged in a circumferential direction.