Quick Clamping Device for Angle Grinders Preventing Inadvertent Release
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Solution Overview
Problem
Existing quick clamping devices for portable power tools, such as angle grinders, often fail to securely fix tools due to inadvertent release caused by tolerance-induced and play-induced movements, especially when subjected to forces decoupled from the operator control unit.
Innovation Solution
Incorporation of a self-locking or detent unit that prevents the clamping element from moving into the release position, even when acted upon by forces not controlled by the operator, using a combination of positive and non-positive locking elements and a spring-loaded mechanism to ensure secure engagement with the tool, and a self-locking contour that provides additional stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a quick clamping device is designed to allow tool-free fixing and quick release, then ease of operation is improved, but reliability deteriorates due to inadvertent release from tolerance-induced and play-induced movements
Solution Approach 1:
The securing unit is designed to preemptively counteract forces that could cause inadvertent release. The positive locking element and self-locking contour are positioned and dimensioned to engage before tolerance-induced or play-induced movements can accumulate enough to trigger release, thus preventing the harmful effect before it occurs.
Solution Approach 2:
The clamping element is designed with inherent self-locking characteristics through its contour geometry and interaction with the positive locking element. Once clamped, the system automatically enters a secured state where the self-locking contour prevents movement into the release position, maintaining reliability without requiring continuous operator input.
2Ease of operation
If the clamping element is made movable with large movement range, then ease of operation is improved, but reliability worsens due to increased susceptibility to play-induced movements
Solution Approach 1:
The self-locking contour is designed to engage with the positive locking element at positions that prevent the clamping element from moving into the release position. This creates a preliminary barrier against play-induced movements, allowing the clamping element to maintain its movable design for ease of operation while preventing inadvertent release.
Solution Approach 2:
The positive locking element acts as an intermediary between the clamping element and the release position. It mediates the movement by providing a mechanical barrier that must be overcome to release, thus allowing large movement range for operation while preventing unintended release from play.
3Reliability
If a securing unit is added to prevent inadvertent release, then reliability is improved, but device complexity increases
Solution Approach 1:
The securing unit is merged with the clamping element design. The self-locking contour is integrated into the clamping element's geometry, and the positive locking element is positioned to work in conjunction with existing clamping components. This merging approach adds reliability while minimizing the increase in device complexity by reusing existing structural elements.
Solution Approach 2:
The securing unit is designed to be self-activating through the interaction between the self-locking contour and positive locking element. The system automatically secures itself when the clamping element is in the clamped position, eliminating the need for additional actuators or complex control mechanisms, thus maintaining simplicity while improving reliability.
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
This solution significantly enhances operator safety by preventing inadvertent tool release and ensuring reliable fixation of tools to the clamping unit and output shaft, even under decoupled forces, thereby maintaining a secure and stable operational state.
Implementation Method 1
the securing unit has at least one spring element which acts on at least one movably mounted positive locking and/or non-positive locking element of the securing unit with a spring force in the direction of the clamping element
Implementation Method 2
The securing unit has at least one movably mounted positive locking and/or non-positive locking element which, at least in the clamping position of the clamping element, engages at least partially into the clamping element
Implementation Method 3
The self-locking contour is oriented such that, in the event of the clamping element being subjected to a force which acts in the direction of the release position of the clamping element, a main securing force can be exerted on the clamping element
Data Source
AI summary
A quick clamping device for a portable machine tool, in particular an angle grinder, includes at least one output shaft, at least one clamping unit, at least one operating unit, and at least one securing unit. The clamping unit, for the purpose of fixing an insert bit to the output shaft without using tools, includes at least one clamping element for applying a clamping force to the bit in a clamping position. The operating unit moves the clamping element into the clamping position and/or into a release position in which the insert bit can be removed from the clamping unit and/or the output shaft. The securing unit is designed to prevent movement of the clamping element from the clamping position into the release position at least under the action of a force decoupled from the operating unit and acting on the clamping element in the direction of the release position.