Protective Hood Stop Structure for Angle Grinder Disc Breakage
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Solution Overview
Problem
Existing hand-held power tools, such as angle grinders, fail to reliably absorb and dissipate the kinetic energy of broken cutting discs, risking damage to the protective guard due to insufficient energy absorption and movement constraints.
Innovation Solution
A hand-held tool design featuring a protective hood with a counter-stop on the motor support unit, which is pivotably mounted and limits the hood's movement to an end position, ensuring high-force transmission and energy absorption through a one-piece metal alloy construction, including a load-bearing structure and interlocking stop surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protective hood is designed to absorb kinetic energy of cutting disc fragments, then safety is improved, but the protective hood may deform or fail under high impact forces
Solution Approach 1:
The patent introduces a stop element as an intermediary component between the protective hood and the motor support unit. This stop element absorbs and redirects impact forces from cutting disc fragments, preventing direct transmission of high impact loads to the protective hood. The stop element acts as a mediator that protects the protective hood from excessive forces while maintaining safety functionality.
2Loss of energy
If the protective hood is constrained to limit pivoting movement, then energy dissipation is improved, but the hood may slip or fail to stop properly without sufficient force transmission
Solution Approach 1:
The patent implements a preliminary action by pre-positioning the stop element and counter-stop in specific locations before impact occurs. The stop element is预先 positioned to intercept the protective hood's pivoting movement, and the counter-stop is pre-configured on the motor support unit to provide a reliable stopping point. This preliminary arrangement ensures that when impact occurs, the energy dissipation and movement constraint functions are immediately activated without delay or failure.
Solution Approach 2:
The patent combines multiple functions into the motor support unit by integrating the counter-stop feature directly into this structural component. The motor support unit serves both as the mounting structure for the drive motor and as the force transmission path for the stop mechanism. This merging ensures that the force transmission path is rigid and reliable, preventing slippage while effectively dissipating kinetic energy through the combined structure.
3Force
If the counter-stop is formed on the motor support unit, then force transmission is improved, but the motor support unit must be of particularly high strength and rigidity
Solution Approach 1:
The patent segments the force transmission function from the main motor support unit body by introducing a dedicated stop element that interfaces between the protective hood and the motor support unit. This segmentation allows the motor support unit to maintain its primary function of supporting the drive motor while the stop element specifically handles the high-force impact loads. The motor support unit needs to be sufficiently rigid to support the motor, but the stop element is the specialized component for force transmission during impact events.
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 design effectively absorbs and dissipates the kinetic energy of broken cutting disc fragments, preventing damage to the tool components by ensuring reliable energy transfer and preventing slippage or deformation of the protective hood.
Implementation Method 1
The design of the counter-stop on the motor support unit ensures that high forces and torques originating from the protective hood can be transmitted to the motor support unit via the stop and the counter-stop
Implementation Method 2
The design of the counter-stop on the motor support unit allows the kinetic energy of the tool components, particularly the cutting disc, housed within the protective hood to be transferred to the motor support unit
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 motor support unit (10) separately formed from the housing (2) and connected to the housing (2), a drive motor (3) arranged in the housing (2) for driving a tool (5) rotating about a rotary axis (8), wherein the drive motor (3) is attached to the motor support unit (10), a protective hood (51), wherein the protective hood (51) at least partially covers the tool (5), wherein a stop (110) is provided on the protective hood (51), and wherein a counter-stop (120) is formed on the motor support unit (10), in particular directly, which is provided for operative connection with the stop (110) of the protective hood (51) in order to limit the pivoting movement of the protective hood (51) to an end position (131).