Hand Tool Relief Device for Easy Clamping Nut Loosening

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Solution Overview

Problem

The clamping nut in hand-held power tools tends to tighten during operation, making it difficult to loosen, and existing relief devices often require complex mechanisms to reduce the axial extent for manual unscrewing.

Innovation Solution

A compact and economically produced relief device with an actuating element that changes its axial extent to facilitate easy loosening of the clamping nut, featuring a first and second functional part with a clamping body and adjusting body, and an integrated design that reduces assembly complexity, utilizing a truncated cone-like section and wedge-like inclined surfaces for force distribution and a guide means for radial movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the clamping nut is tightened to secure the tool during operation, then the tool holding stability is improved, but the clamping nut becomes difficult to loosen manually

Engineering Contradiction:
Improvetool holding stabilityVSAvoidease of loosening clamping nut
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The relief device incorporates a dynamic mechanism where the actuating element can shift between two functional positions. In the first position, the relief device maintains maximum axial extension to preserve high clamping force for stable tool holding. In the second position, the actuating element causes the clamping body to move radially outward, reducing the axial extent of the relief device and thereby reducing the compressive force on the clamping nut, enabling easy manual loosening.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the axial extent parameter of the relief device by shifting between functional positions. When the actuating element is in the first functional position, the relief device has maximum axial extension. When shifted to the second functional position, the axial extent is reduced, which directly reduces the compressive force between the clamping nut and the tool, facilitating manual unscrewing.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a relief device is added to enable easy loosening of the clamping nut, then the ease of operation is improved, but the device complexity increases

Engineering Contradiction:
Improveease of loosening clamping nutVSAvoidrelief device structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The relief device is integrated into the clamping nut as a pre-assembled assembly. The clamping nut and relief device form a unified structure where the first functional part, second functional part, clamping body, and adjusting body are combined. This merging simplifies the overall assembly process, as the integrated unit can be installed as a single component rather than assembling multiple separate parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The relief device is segmented into distinct functional components: the first functional part, second functional part, clamping body, and adjusting body. Each segment has a specific function, and their modular arrangement allows for simplified manufacturing and assembly while maintaining the complex functionality needed for easy loosening operation.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the axial extent of the relief device is reduced to loosen the clamping nut, then the ease of operation is improved, but the clamping force is reduced

Engineering Contradiction:
Improveease of loosening clamping nutVSAvoidclamping force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The relief device uses a dynamic position-shifting mechanism with an actuating element that can move between two functional positions. In the first position, the device maintains maximum axial extension to provide high clamping force during operation. In the second position, the actuating element causes radial outward movement of the clamping body, reducing axial extent and clamping force only when loosening is needed. This dynamic adjustment allows the system to provide high force when required while enabling easy loosening when needed.

Inventive Principle:
Principle #15Dynamics

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 simple manual loosening of the clamping nut by reducing the axial extent of the relief device, reducing compressive force and simplifying assembly, while minimizing wear through extensive contact and power transmission.

Implementation Method 1

the first functional part and/or the second functional part has a truncated cone-like section, so that the clamping body is pressed radially outwards by the first functional part and/or by the second functional part. The truncated cone-like section with its sloping surface is preferably inclined at an angle of between 45° and 80°... to the axis of rotation of the drive spindle (cone axis). As a result, the compressive force acting axially is split into a force component acting radially outwards

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

The clamping body can rest linearly on the first functional part and/or on the second functional part. A clamping body which has a wedge-like inclined surface is preferred. As a result, extensive contact with the functional parts can be achieved, which is considered to be advantageous. The wedge-like inclined surface can be formed on one side or on both sides... extensive contact with the functional parts can be achieved... reduces wear on the parts

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2103385B1Hand tool device
Publication Date: 2015.09.02 METABOWERKE
  • EP2103385B1 patent drawingFigure 1
  • EP2103385B1 patent drawingFigure 2~3

AI summary

The device has an unloading device (4) provided with a set of functional parts (6, 8). An adjusting body (16) fixes a clamping body (14) against a movement radially outside in such a manner that the clamping body supports the functional parts in an axial direction. An operating device e.g. actuator (12), is operated in the axial direction and directly or indirectly fixes the adjusting body against the movement in an unoperated functional position and enables the movement of the adjusting body in an operated functional position.