Socket Spanner Retaining Mechanism Using Shrink Tube Spring

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Solution Overview

Problem

Existing socket wrench designs are complex in production and handling, with inefficiencies in retaining mechanisms that can lead to loss of elastic return function and frictional holding.

Innovation Solution

A socket wrench with a spring element formed by a shrink tube shrunk onto the wall, where the holding element is a sphere creating a bulge in the shrink tubing, providing optimized spring effect and force distribution for secure engagement with polygonal screw heads or nuts, and optionally featuring multiple holding elements and a single spring element acting radially inward on both.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring element with a ring shape extending through the window is used (DE 20 2008 010206 U1), then the elastic return function is provided, but the device complexity increases and production becomes more difficult

Engineering Contradiction:
Improveelastic return functionVSAvoidspring element structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the physical state and geometric parameters of the spring element by forming it as an integrated protrusion on the polygonal wall rather than a separate ring component. This integration simplifies the structure while maintaining the elastic return function through the protrusion's flexibility and deformation capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The spring element is merged with the polygonal wall structure, forming an integrated component where the spring function is built into the wall itself. This eliminates the need for separate ring-shaped spring components and reduces assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple holding elements are used to improve retention, then the secure engagement increases, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improveretention securityVSAvoidholding element configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The holding function is segmented into multiple holding elements (balls or protrusions) distributed around the polygonal opening. Each holding element independently contributes to retention, providing secure engagement without requiring a complex integrated mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The polygonal wall structure serves multiple functions: it provides structural support, contains the holding elements, and integrates the spring element. This multi-functionality reduces the need for separate components while maintaining retention security.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If the holding element is positioned adjacent to the opening-side edge, then the engagement is easier, but the spring effect and force distribution are reduced

Engineering Contradiction:
Improveengagement easeVSAvoidspring effect
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The holding element is positioned in the axial dimension between the opening-side edge and bottom edge, rather than only at the opening-side edge. This axial positioning allows the spring element to exert radial force effectively while maintaining engagement capability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enhances the spring effect and secure retention of screw heads or nuts with improved force distribution, simplifying production and handling by ensuring effective frictional engagement and preventing loss of elastic return.

Implementation Method 1

the spring element is a shrink tube shrunk onto the wall

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 2

The holding element is preferably formed by a sphere which leaves a bulge in the shrink tubing made of plastic

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 3

With the ball, the polygonal screw head or the polygonal nut is held in the polygonal opening by friction

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3046731B1Socket
Publication Date: 2020.05.06 WERA WERKZEUGE GMBH
  • EP3046731B1 patent drawingFigure 1
  • EP3046731B1 patent drawingFigure 2
  • EP3046731B1 patent drawingFigure 3

AI summary

A socket spanner including a drive head, which forms a polygonal profile opening that can be plugged onto a polygonal bolt head or a polygonal screw nut, and includes a retaining element enclosed in a window of the wall of the polygonal profile opening, which retaining element is acted on by a spring element arranged outside the wall. In order to simplify such a socket spanner in terms of manufacturing technology and/or to improve it in terms of handling, it is proposed that the spring element is a shrinkable tube which is shrink-fitted on the wall.