Angle Grinder Tool Holder for Tool-Free High-Speed Clamping

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Solution Overview

Problem

Hand-held machine tools, such as angle grinders, face challenges in quickly and conveniently attaching and detaching tools without the need for additional securing elements, particularly at high rotational speeds where traditional clamping methods are inadequate.

Innovation Solution

A tool holder device that allows for the tool to be clamped by a movable clamping device with hook devices that can pivot relative to the driver device, enabling tool change without tools, such as fastening screws, and providing increased clamping force due to centrifugal force at higher speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional clamping methods are used, then tool attachment is secure, but tool change requires additional tools and time

Engineering Contradiction:
Improvetool change convenienceVSAvoidtool change time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The clamping device is designed to be actuated directly by the tool device itself during the tool change process. When the tool device is inserted or removed, it automatically triggers the clamping mechanism to open or close, eliminating the need for separate fastening tools and enabling quick tool changes without additional time loss

Inventive Principle:
Principle #25Self-service

2Reliability

If additional securing elements are used, then tool attachment is more secure, but device complexity increases

Engineering Contradiction:
Improvetool attachment securityVSAvoidclamping mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The clamping device integrates multiple functions into a single mechanism: it provides both the clamping force to secure the tool and the actuation mechanism to open/close during tool changes. The hook devices combine the securing function with the motion transmission function, eliminating the need for separate fastening elements and reducing overall device complexity while maintaining attachment security

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The clamping device transitions from a static clamping mechanism to a dynamic one that automatically opens and closes during tool changes. The hook devices can pivot between engaged and disengaged positions, allowing the mechanism to adapt its state based on whether a tool is being attached or removed, thereby maintaining security during operation while enabling quick changes

Inventive Principle:
Principle #15Dynamics

3Strength

If clamping force is increased for high speed operation, then tool stability improves, but clamping device complexity increases

Engineering Contradiction:
Improveclamping forceVSAvoidclamping device structure
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The hook devices are positioned and dimensioned to create a mechanical advantage that generates increased clamping force during high-speed rotation. The geometry of the hook devices and their pivot points are designed so that centrifugal forces at high speeds automatically increase the clamping pressure on the tool device, providing enhanced tool stability without requiring additional active clamping mechanisms

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The clamping force parameter changes dynamically with rotational speed. At higher speeds, the centrifugal effects and dynamic loads automatically increase the clamping force exerted by the hook devices, allowing the system to adapt to high-speed operation requirements without manual intervention or complex control systems

Inventive Principle:
Principle #35Parameter 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

Enables quick and secure tool changes without additional tools, maintaining tool alignment and stability during operation, even at high rotational speeds.

Implementation Method 1

providing increased clamping force due to centrifugal force at higher speeds

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3500401B1Power tool
Publication Date: 2022.04.13 ROBERT BOSCH GMBH
  • EP3500401B1 patent drawingFigure 1
  • EP3500401B1 patent drawingFigure 2
  • EP3500401B1 patent drawingFigure 3

AI summary

The invention relates to a power tool (211), in particular a hand-held power tool, preferably an angle grinder, which has a tool-holding device (213), which can be rotated about an output axis (A), wherein said tool-holding device (213) is designed to hold a tool device (11), in particular an insert tool, on the power tool (211) in such a way that the output axis (A) and a tool axis of rotation (a) substantially coincide, wherein the tool-holding device (213) has at least a driver device (215) and a clamping device (217), which can be moved relative to the driver device (215), wherein, in order to transfer a driving force to the tool device (11), said driver device (215) has at least one torque transfer region (219), which is arranged at a distance from said output axis (A). According to the invention, the driver device (215) and the clamping device (217) are provided for reaching through a cut-out (17) of the tool device (11), which cut-out in particular extends through the entire material thickness of the tool device (11), and to clamp the tool device (11) by means of the clamping device (217), which can be moved substantially in a direction radial to the output axis (A).