Quick Clamping Mechanism With Speed-Triggered Decoupling

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Solution Overview

Problem

Existing quick-action clamping devices for portable machine tools, such as angle grinders, face challenges in securely fixing tools at high rotational speeds, leading to potential detachment of tools during operation, which compromises operator safety and tool security.

Innovation Solution

A quick-action clamping device with a decoupling unit that automatically disconnects the operating unit from the clamping unit at high rotational speeds, utilizing centrifugal, friction, or spring-based mechanisms to prevent actuation of the clamping element, ensuring tool retention and enhanced safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the operating unit is connected to the clamping unit for tool-free fixing, then ease of operation is improved, but reliability deteriorates at high rotational speeds due to potential tool detachment

Engineering Contradiction:
Improvetool-free fixingVSAvoidtool security at high speeds
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies a dynamic decoupling mechanism that automatically disconnects the operating unit from the clamping unit when rotational speed exceeds a predetermined threshold. This allows the system to adapt its connectivity based on operating conditions, maintaining ease of operation at low speeds while ensuring tool security at high speeds through automatic decoupling.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces a decoupling unit as an intermediary component between the operating unit and the clamping unit. This mediator automatically engages or disengages based on rotational speed, preventing direct force transmission from the operating unit to the clamping element when speeds are high, thus avoiding tool detachment while maintaining normal operation at safe speeds.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the clamping element is movable for exerting clamping force, then ease of operation is improved, but device complexity increases due to additional decoupling mechanisms

Engineering Contradiction:
Improvemovable clamping elementVSAvoiddecoupling unit structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The decoupling unit is designed to automatically detect rotational speed and self-actuate the decoupling action without requiring external control systems, sensors, or complex electronic components. The mechanism uses the rotational energy itself to trigger the decoupling, thereby maintaining ease of operation while minimizing added complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the operational parameter of the clamping mechanism from a static connected state to a dynamically variable state based on rotational speed. The decoupling unit modifies the force transmission parameter automatically, allowing the system to transition between coupled and decoupled states without requiring complex control systems.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the decoupling unit prevents force transmission at high speeds, then reliability is improved, but ease of operation deteriorates due to restricted control

Engineering Contradiction:
Improveprevention of tool detachmentVSAvoidcontrol of clamping element
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The decoupling mechanism dynamically adjusts force transmission based on rotational speed thresholds. Below the threshold, full control is maintained for ease of operation; above the threshold, decoupling occurs to prevent tool detachment. This dynamic adaptation resolves the contradiction by making the system behavior context-dependent.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent converts the potentially harmful high-speed rotational energy into a beneficial automatic protection mechanism. The rotational speed itself triggers the decoupling action that prevents tool detachment, transforming the dangerous condition into a self-protecting feature that maintains reliability without requiring external intervention.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 tool detachment at high speeds, ensuring operator safety and reliable tool fixation, even during intense operation, by automatically decoupling the operating unit from the clamping unit, thus enhancing the safety and reliability of the clamping mechanism.

Implementation Method 1

A quick-action clamping device with a decoupling unit that automatically disconnects the operating unit from the clamping unit at high rotational speeds, utilizing centrifugal, friction, or spring-based mechanisms

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

A quick-action clamping device with a decoupling unit that automatically disconnects the operating unit from the clamping unit at high rotational speeds, utilizing centrifugal, friction, or spring-based mechanisms

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

A quick-action clamping device with a decoupling unit that automatically disconnects the operating unit from the clamping unit at high rotational speeds, utilizing centrifugal, friction, or spring-based mechanisms

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3528985B1Quick clamping device for a portable power tool having at least one rotatably drivable output shaft, in particular an angle grinder
Publication Date: 2022.12.07 ROBERT BOSCH GMBH
  • EP3528985B1 patent drawingFigure 1~2
  • EP3528985B1 patent drawingFigure 3~4
  • EP3528985B1 patent drawingFigure 5~6

AI summary

The invention relates to a quick clamping device for a portable power tool having at least one rotatably drivable output shaft (12a; 12b; 12c; 12e; 12l), in particular an angle grinder, comprising at least one clamping unit (16a; 16b; 16c; 16d; 16e; 16f; 16g; 16h; 16h'; 16i; 16j; 16k; 16l; 16m; 16n), which has, for tool-free fastening of an insert tool unit (18a) to the output shaft (12a; 12b; 12c; 12e; 12l), at least one movably mounted clamping element (20a, 22a; 20b, 22b; 20c, 22c) for applying clamping force to the insert tool unit (18a) in a clamping position of the clamping element (20a, 22a; 20b, 22b; 20c, 22c), and comprising at least one operating unit (24a; 24b; 24c; 24d; 24e; 24f; 24h; 24h'; 24i; 24j; 24k; 24l; 24n) for moving the clamping element (20a, 22a; 20b, 22b; 20c, 22c) into the clamping position and/or into a release position of the clamping element (20a, 22a; 20b, 22b; 20c, 22c), in which the insert tool unit (18a) can be removed from the clamping unit (16a; 16b; 16c; 16d; 16e; 16f; 16g; 16h; 16h'; 16i; 16j; 16k; 16l; 16m; 16n). According to the invention, the quick clamping device comprises at least one uncoupling unit (26a; 26b; 26c; 26d; 26e; 26f; 26g; 26h; 26h'; 26i; 26j; 26k; 26l; 26m; 26n) for uncoupling the operating unit (24a; 24b; 24c; 24d; 24e; 24f; 24h; 24h'; 24i; 24j; 24k; 24l; 24n) from the clamping unit (16a; 16b; 16c; 16d; 16e; 16f; 16g; 16h; 16h'; 16i; 16j; 16k; 16l; 16m; 16n) in accordance with the rotational speed of the output shaft (12a; 12b; 12c; 12e; 12l).