Retention Flange Assembly for Grinding Wheel Braking Stability
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Solution Overview
Problem
Existing power tool braking mechanisms fail to prevent grinding wheel detachment due to high inertia during rapid deceleration, especially when a hubbed grinding wheel is used without an outer tightening nut, as the friction between the wheel and the output spindle is insufficient to counteract the wheel's inertia.
Innovation Solution
A power tool design featuring a retention flange with a disc-shaped portion and a cylindrical wall, where spring members bias the flange away from the annular rim, and a retention member engages the flange and rim to limit displacement, increasing friction between the wheel and spindle through a retaining ring and annular shoulder contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a hubbed grinding wheel is used without an outer tightening nut, then the device complexity is reduced, but the reliability deteriorates because the friction between the wheel and output spindle is insufficient to prevent wheel detachment during rapid deceleration
Solution Approach 1:
A retention flange is introduced as an intermediary component between the grinding wheel and the output spindle. The retention flange includes a disc-shaped portion and a cylindrical wall, with spring members and retention members that engage with the output spindle's annular rim to prevent wheel detachment during braking without requiring an outer tightening nut
Solution Approach 2:
The retention flange is segmented into functional components: a disc-shaped portion for positioning, a cylindrical wall for structural support, spring members for applying retention force, and retention members for engaging the annular rim. This segmentation allows each component to perform its specific function while collectively solving the wheel retention problem
2Reliability
If spring members are added to increase friction between the wheel and spindle, then the reliability improves, but the device complexity increases
Solution Approach 1:
The spring members are configured to automatically engage and disengage with the retention members based on the operational state. During normal operation, the springs maintain friction between the wheel and spindle. During rapid deceleration, the retention members automatically engage with the annular rim to prevent detachment, eliminating the need for external tightening nuts while maintaining simplicity
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 effectively increases the frictional force between the grinding wheel and the output spindle, significantly reducing the likelihood of the wheel coming off during braking, while also simplifying the manufacturing and assembly process by allowing a self-supported wheel retention mechanism.
Implementation Method 1
At least one spring member is provided engaging a first surface of the annular rim on one end and the disc-shaped portion on another end to bias the retention flange in a direction away from the annular rim
Data Source
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AI summary
A power tool is provided including an output spindle (24) rotatably driven by an electric motor. The output spindle defines a longitudinal axis and includes a threaded portion (214) near a distal end and an annular rim (210) . A retention flange (202) is provided including a radially-oriented disc-shaped portion having a center through-hole through which the output spindle extends and a cylindrical wall peripherally extending from the disc-shaped portion around the output spindle. The disc-shaped portion (220) is located between the distal end (214) and the annular rim (210) , and the cylindrical wall extends around the annular rim. At least one spring member (204) is disposed between the annular rim (210) and the retention flange (202) . A retention member (206) is provided to restrain an axial displacement of the retention flange (202) away from the annular rim (210) due to the biasing force of the spring member (204).