Tool Spindle Support Element Prevents Loosening
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Solution Overview
Problem
Electric hand tools, particularly angle grinders, face safety issues due to the risk of tool detachment when using spindle brakes, as the torque reversal can loosen the fastening nut, leading to potential tool ejection during braking.
Innovation Solution
A rotatable tool spindle with a support element that applies a defined axial force to the tool, generating a preload that secures the tool against unintentional loosening, even during braking, by increasing frictional engagement between the threads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spindle brake is used to quickly stop the rotating tool, then the braking time is reduced and productivity is improved, but the torque reversal causes the fastening nut to loosen and the tool may detach, compromising safety
Solution Approach 1:
The patent applies preliminary anti-action by introducing a support element that proactively counteracts the loosening torque before it can cause tool detachment. The support element is positioned to provide stabilizing force during braking, preventing the fastening nut from loosening due to the reverse torque generated when the spindle brake stops the rotating tool.
Solution Approach 2:
The support element acts as an intermediary component between the fastening nut and the tool. It mediates the force transmission during braking by providing additional support to the fastening system, distributing the reverse torque and preventing the fastening nut from loosening while allowing the tool to be securely held during operation.
2Reliability
If wedge surfaces are used to increase pressure between flanges during braking, then tool detachment is prevented, but the tension between flanges becomes dependent on braking intensity, requiring different torques for tool release and potentially preventing easy tool changes
Solution Approach 1:
The support element is designed to automatically engage and provide stabilizing force during braking without requiring operator intervention. It self-adjusts to the braking conditions and provides the necessary counteracting force, then automatically disengages or reduces its effect when braking is complete, allowing the operator to remove the tool with standard torque without excessive resistance.
Solution Approach 2:
The support element provides dynamic support that adapts to the braking conditions. During braking, it actively counteracts the reverse torque; after braking, its effect is reduced or eliminated, allowing the fastening nut to be removed with normal torque. This dynamic behavior ensures tool security during operation while maintaining ease of tool changes.
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 prevents unintentional loosening and tool detachment, allowing for safe operation and quick tool changes without additional effort or training, while maintaining a simple and robust construction.
Implementation Method 1
generating a preload that secures the tool against unintentional loosening, even during braking, by increasing frictional engagement between the threads
Data Source
Figure 1
AI summary
The invention relates to an electric hand-power tool device comprising a rotatable tool spindle for receiving a tool, said tool spindle having a supporting element for supporting the tool. The supporting element (13) is designed such that the tool (1) can be moved on a path L in an axial manner along the tool spindle (3) in the direction of the electric hand-power tool against a force (F) after said tool comes into contact with the supporting element (13) when the tool (1) is received on the tool spindle (3).