Grinding Workpiece Clamping Device Axial Force Transmission

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Solution Overview

Problem

Existing clamping devices for grinding machines suffer from precision issues due to thermal deformations and transverse forces, affecting the accuracy of grinding operations, especially when clamping disc-shaped workpieces for both circumferential and contour grinding.

Innovation Solution

A clamping device with a counter-ram axially immovable and accommodated in a base body, featuring a linearly displaceable guide block for the rotatable and axially displaceable clamping ram, ensuring only axial force transmission without radial components, and a servomotor for controlled rotary drive, allowing precise alignment and integration into conventional grinding machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a C-shaped holding element is used to guide the clamping ram, then the device structure is simplified, but thermal deformations cause misalignment of the rams affecting grinding accuracy

Engineering Contradiction:
Improvestructure simplicityVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The device is divided into functionally independent components: the base body with counter-ram remains stationary while the guide block and clamping ram form a movable assembly. This segmentation allows the stationary part to maintain precision while the movable part accommodates thermal expansion and force variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The guiding function is extracted from the base body and transferred to the guide block, which is specifically designed to provide linear guidance. This separates the functions of support, guidance, and clamping, allowing each component to be optimized for its specific function and reducing cumulative errors.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If the clamping ram is freely displaceable to accommodate workpiece variations, then adaptability is improved, but radial force components cause misalignment and reduce precision

Engineering Contradiction:
Improveworkpiece accommodationVSAvoidram alignment
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The guide block acts as an intermediary between the base body and the clamping ram. It provides linear guidance that allows axial displacement for adaptability while constraining radial movements, thus preventing misalignment. The guide block mediates between the need for freedom of movement and the requirement for precise alignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the counter-ram is made axially movable to increase flexibility, then operational flexibility is improved, but alignment precision and stability deteriorate

Engineering Contradiction:
Improveclamping flexibilityVSAvoidalignment stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The clamping function is segmented between the stationary counter-ram (providing stability) and the movable clamping ram (providing flexibility). The counter-ram remains fixed in the base body to ensure stable alignment reference, while the clamping ram moves independently to accommodate different workpieces.

Inventive Principle:
Principle #1Segmentation

4Stability of the object's composition

If thermal expansion of the holding element is allowed, then thermal stress is reduced, but dimensional stability and alignment precision are compromised

Engineering Contradiction:
Improvethermal stress reliefVSAvoiddimensional stability
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The device structure is segmented into thermally independent zones: the base body with counter-ram serves as a stable reference that can be thermally isolated, while the guide block and clamping ram assembly can expand freely in the axial direction without affecting the precision reference established by the counter-ram.

Inventive Principle:
Principle #1Segmentation

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 ensures high precision in workpiece alignment and clamping, preventing deformations and transverse forces, enabling simultaneous and precise grinding of both circumference and contour, thereby enhancing processing accuracy and efficiency.

Implementation Method 1

a guide block (40) which is linearly displaceable in the base body (30) in a direction parallel to the clamping axis

Methodology Applied
Scientific EffectLinear guidance:

Implementation Method 2

a ball (62) which can rotate freely but is axially supported, with which the pivoting lever (58) acts on the clamping ram (46)

Methodology Applied
Scientific EffectSpherical force transmission: Ball

Implementation Method 3

the actuating rod (50) is preferably acted upon axially by a spring force

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 4

a servomotor, which brings about the controlled rotary drive of the counter-ram, is accommodated in the base body (30)

Methodology Applied
Scientific EffectServo motor drive: Linear Motor

Data Source

PatentEP2161101B1Device for tensioning a workpiece for processing in a grinding machine
Publication Date: 2011.08.31 ADELBERT HAAS GMBH
  • EP2161101B1 patent drawingFigure 1
  • EP2161101B1 patent drawingFigure 2
  • EP2161101B1 patent drawingFigure 3

AI summary

The device comprises a base body (30), which is mounted at a workpiece spindle of the grinding machine. A tension axle cuts the rotation axis of the workpiece spindle orthogonally. A clamping ram (46) is guided in a guiding block (40) in freely rotating manner. An actuator transfers clamping force to the clamping ram with transmission units, which allow an axial but not radial force transmission.