Protective Hood Stop Design for Angle Grinder Burst Energy Absorption
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Solution Overview
Problem
Existing hand-held power tools, such as angle grinders, face challenges in reliably absorbing and dissipating the kinetic energy of broken cutting disc parts during a burst test, where the protective guard must limit its movement while effectively managing the energy absorption.
Innovation Solution
The hand-held tool incorporates a protective hood with an operating stop designed as an energy absorption element that yields under overload, featuring a counterbody and end stop to limit pivoting movement, and is made of metal alloys for enhanced strength and durability, with specific geometric configurations to manage kinetic energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operating stop is made rigid to reliably limit pivoting movement of the protective hood, then the limitation function is improved, but the operating stop cannot absorb kinetic energy during burst tests, causing damage to the counterbody
Solution Approach 1:
The operating stop is designed to change its mechanical properties dynamically: under normal operating conditions it maintains high rigidity to reliably limit pivoting movement, but under overload conditions (burst test) it yields through predetermined breaking or deformation to absorb kinetic energy. This dynamic transition from rigid to yielding state resolves the contradiction between reliable limitation and energy absorption capacity.
Solution Approach 2:
The operating stop's structural parameters (strength, rigidity) are designed to change under different load conditions. The element is configured with specific geometric features and material properties that allow it to maintain integrity during normal use but undergo controlled breaking or deformation when exposed to excessive kinetic energy from burst tests, thus adapting its parameters to match operational requirements.
2Strength
If the operating stop yields under overload to absorb kinetic energy, then the energy absorption function is improved, but the limitation function may be compromised
Solution Approach 1:
The operating stop transitions from a rigid state during normal operation to a yielding state under overload, dynamically adapting its mechanical behavior to the operational conditions. This ensures reliable limitation during normal use while enabling energy absorption during abnormal conditions like burst tests.
Solution Approach 2:
The operating stop is pre-designed with predetermined breaking points or deformation zones that are prepared in advance to absorb kinetic energy during burst tests. This beforehand preparation ensures that when overload occurs, the element can immediately yield and absorb energy without compromising the limitation function during normal operation.
3Device complexity
If the protective hood is designed with integrated counterbodies for both operating stop and end stop, then the device complexity is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
Multiple counterbodies (for operating stop and end stop) are merged into a single integrated protective hood structure. This consolidation reduces the total number of separate components and simplifies assembly, while the manufacturing process is designed to achieve the required positioning precision for each counterbody location.
Solution Approach 2:
While the protective hood is integrated, the counterbodies are positioned at distinct locations and serve separate functions. This functional segmentation within the integrated structure allows each counterbody to be optimized for its specific purpose while maintaining overall design 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 ensures reliable limitation of pivoting movement and prevents damage to the counterbody by absorbing kinetic energy, even in high-energy scenarios, maintaining tool integrity and safety.
Implementation Method 1
The operating stop can be deformed upon impact by material deformation. This deformation can be elastic and/or plastic.
Implementation Method 2
The operating stop can be deformed upon impact by material deformation. This deformation can be elastic and/or plastic.
Implementation Method 3
The operating stop is designed as an energy absorption element which, in the event of an overload acting upon it by the counterbody, yields to the counterbody in order to absorb the kinetic energy of the protective hood
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a hand-held work device comprising a housing (2), a drive motor (3) arranged in the housing (2) for driving a tool (5) rotating about a rotary axis (8), a protective hood (51) wherein the protective hood (51) at least partially covers the tool (5), an operating stop (120) fixed relative to the housing (2) and a counter body (110) corresponding to the operating stop (120) and arranged on the protective hood (51), wherein the operating stop (120) is designed as an energy absorption element which, in the event of an overload acting on the operating stop (120) by the counter body (110), yields to the counter body (110) in order to absorb kinetic energy of the protective hood (51) and to protect the component of the counter body (110), and wherein the work device (1) comprises an end stop (101) for limiting the rotational movement of the protective hood (51) to an end position (25).