Angle Grinder Spindle Locking Against Wheel Detachment
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Solution Overview
Problem
Existing angle grinders face issues with grinding wheels detaching during sharp acceleration or deceleration due to loose nuts, necessitating expensive, specifically designed wheels, and existing solutions are not cost-effective for various types and sizes.
Innovation Solution
A spindle design with a securing device that has an outer diameter larger than the spindle during operation, featuring a rotary joint, internal/external threads, spring rings, or levers to prevent detachment, allowing secure attachment of grinding wheels without additional safety devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a nut is used to secure the grinding wheel on the spindle, then the wheel can be attached to the spindle, but the nut can loosen during sharp acceleration or deceleration, causing the wheel to detach
Solution Approach 1:
The securing function is divided into two independent elements: a threaded connection element (nut or integrated thread) for basic attachment, and a separate locking element with larger outer diameter that provides additional security against loosening during operation. This segmentation allows each element to perform its specific function optimally while maintaining cost-effectiveness.
Solution Approach 2:
The locking element is designed to automatically engage and lock the grinding wheel to the spindle before operation begins. The larger outer diameter of the locking element creates a mechanical interference fit that preliminarily secures the wheel, preventing any loosening that might occur during subsequent acceleration or deceleration cycles.
2Reliability
If specifically designed grinding wheels with integrated safety features are used, then secure attachment is ensured, but the wheels become expensive to produce
Solution Approach 1:
The safety/locking function is extracted from the grinding wheel itself and placed in a separate locking element that is part of the angle grinder tool. This allows standard, cost-effective grinding wheels to be used while the separate locking element provides the necessary security features. The wheel remains a simple, inexpensive component.
Solution Approach 2:
The locking element acts as an intermediary between the grinding wheel and the spindle. It mediates the connection by providing both threaded engagement with the spindle and radial locking against the wheel flange, enabling secure attachment without requiring complex integration into the wheel itself.
3Reliability
If a securing device with larger outer diameter than the spindle is provided, then detachment is prevented, but the device complexity increases
Solution Approach 1:
The locking element combines multiple functions in a single component: threaded engagement with the spindle, radial extension beyond the spindle diameter for locking, and contact surfaces for securing the grinding wheel. This merging of functions into one element simplifies the overall device structure compared to using multiple separate components.
Solution Approach 2:
The locking element is designed as a universal component that can secure various types of grinding wheels (with different flange configurations) to the spindle. Its multi-functional design allows it to serve as both the primary attachment mechanism and the safety lock, reducing the need for wheel-specific safety devices.
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
Ensures secure attachment of grinding wheels regardless of type or size, preventing detachment during operation, ensuring user safety and cost-effective use of various machining elements.
Implementation Method 1
wird durch die Krafteinwirkung während des Betriebs des Maschinenwerks in eine Verwendungslage versetzt, in der der Sicherungsbereich einen größeren Außendurchmesser aufweist als der Außendurchmesser des Spindels
Implementation Method 2
wird durch die Krafteinwirkung während des Betriebs des Maschinenwerks in eine Verwendungslage versetzt, in der der Sicherungsbereich einen größeren Außendurchmesser aufweist als der Außendurchmesser des Spindels
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
The invention relates to a machine tool (1), in particular an angle grinder, having a spindle (8) which is drivable about a rotation axis (L), wherein a device (9) is provided which can be fixed to the spindle (8) by means of a slewing ring. A separate securing device (26), operatively connected to the spindle (8), is provided, which is arranged at least in regions on the output side of the device (9) and, at least during operation of the machine tool (1), has a greater outside diameter (28), in respect of the rotation axis (L), at least in regions than an outside diameter (14) of the spindle (8).