Offset Pressing Plane for Eccentric Workpiece Holding

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Solution Overview

Problem

Existing devices for fine machining of rotationally symmetrical workpieces face issues with radial clamping, where the workpieces can be damaged due to contact with clamping tools, and lateral movement during machining, leading to accuracy and concentricity problems.

Innovation Solution

A device with a pressing plane offset from the axis of rotation, allowing for eccentric positioning, which generates a transverse force to hold the workpiece in place without the need for a third guide device, and ensures that the pressing forces act as normal forces, preventing lateral migration and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If radial clamping is used to prevent lateral movement, then machining precision is improved, but workpiece surface is damaged

Engineering Contradiction:
Improvemachining precisionVSAvoidworkpiece surface damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the clamping approach from radial to axial direction. Instead of clamping the workpiece radially (perpendicular to axis), the pressing device applies force axially (parallel to axis), preventing lateral migration without contacting the radial surface that needs machining.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The pressing device acts as an intermediary mechanism that converts axial pressing force into effective lateral constraint. By positioning the pressing plane offset from the axis of rotation, the axial force creates a transverse component that prevents lateral movement without direct radial contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If two guide devices are used with offset distances to prevent lateral migration, then lateral stability is improved, but concentricity is compromised due to stick-slip effects

Engineering Contradiction:
Improvelateral stabilityVSAvoidconcentricity
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The pressing plane is positioned asymmetrically (offset) relative to the axis of rotation, creating an intentional eccentric arrangement. This asymmetric positioning generates a transverse force component that stabilizes the workpiece laterally without requiring symmetric guide device coordination.

Inventive Principle:
Principle #4Asymmetry

3Stability of the object's composition

If three guide devices are used to prevent lateral movement, then workpiece stability is improved, but device complexity increases

Engineering Contradiction:
Improveworkpiece stabilityVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for the third guide device by using the offset pressing plane to provide the necessary transverse stabilizing force. The axial pressing mechanism with eccentric positioning replaces the function that would otherwise require an additional radial guide device.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If axial pressing with offset pressing plane is used, then device simplicity is improved, but understanding of force mechanics becomes more complex

Engineering Contradiction:
Improvedevice simplicityVSAvoidforce mechanics understanding
Core Design Contradiction:
Device complexityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent changes the geometric parameter of the pressing plane position (offset distance from axis) to alter the force distribution. By adjusting this parameter, the device achieves both simplicity in structure and control over the transverse force component generated during axial pressing.

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

This solution allows for precise and gentle machining of workpieces with reduced wear and improved concentricity, eliminating the need for complex distance coordination between guide devices and the axis of rotation.

Implementation Method 1

the offset of the pressing plane is sufficient to generate a transverse force which presses the workpiece in the direction of the guide devices

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

A tool acting in the radial direction exerts a force on the workpiece to be machined so that, unless further measures are taken, it can move laterally with respect to the axis of rotation

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2218545B1Device and method for fine processing of a rotation-symmetric workpiece surface
Publication Date: 2011.08.24 SUPFINA GRIESHABER GMBH & CO KG
  • EP2218545B1 patent drawingFigure 1
  • EP2218545B1 patent drawingFigure 2
  • EP2218545B1 patent drawingFigure 3~7

AI summary

The device (10) has a finishing tool (38) i.e. finishing stone, for pressing workpieces (14) against a drive equipment (12) with a pressing device (42). Each workpiece is arranged between the device equipment and the pressing device in a direction of a rotation axis (16). The pressing device is operated in a contact pressure layer and staggered from the rotation axis in the direction towards a region. Guide equipments (20, 22) are arranged in the region such that the contact pressure layer is positioned relative to the rotation axis and staggered in the direction of the guide equipments. An independent claim is also included for a method for fine or precision machining rotationally symmetric workpiece area.