Index Table Eccentric Load Cancellation for Surface Shape Measuring Devices

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Solution Overview

Problem

Existing surface shape measuring devices face challenges in maintaining measurement accuracy when using an index table due to limited movable range and potential fluctuations in the center of gravity, making it difficult to accurately measure multiple workpieces.

Innovation Solution

A surface shape measuring device with a rotary table, an index table that can move along perpendicular axes, and eccentric load cancelling mechanisms, such as counterweights, to extend the movable range and maintain measurement accuracy by aligning the workpiece center axis with the rotation center axis and cancelling eccentric loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If an index table is added to extend the movable range, then the movable range is extended, but the measurement accuracy deteriorates due to center of gravity fluctuation

Engineering Contradiction:

Improvemovable rangeVSAvoidmeasurement accuracy

Core Design Contradiction:

Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies counterweights to the index table to balance the center of gravity fluctuations that occur during indexing operations. By positioning counterweights opposite to the eccentric load, the system cancels out the gravitational variations, thereby maintaining measurement accuracy while utilizing the extended movable range provided by the index table.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

2Adaptability or versatility

If the movable range is extended to accommodate multiple workpieces, then multiple workpieces can be measured, but the center of gravity fluctuates causing measurement errors

Engineering Contradiction:

Improvecapability to measure multiple workpiecesVSAvoidmeasurement accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The counterweight mechanism compensates for center of gravity shifts when different workpieces are positioned on the index table, ensuring consistent measurement accuracy across multiple workpieces while maintaining the enhanced versatility of measuring multiple items.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The system performs preliminary centering operations using the centering mechanism before measurement to align the workpiece center axis with the rotation center axis, and the counterweights are pre-positioned to compensate for expected center of gravity fluctuations, ensuring measurement accuracy is maintained from the start of the measurement process.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If an index table without center of gravity control is used, then the device complexity is reduced, but measurement accuracy deteriorates

Engineering Contradiction:

Improvestructural simplicityVSAvoidmeasurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The counterweight system adds minimal structural complexity to the index table while effectively canceling center of gravity fluctuations. This provides a simple yet effective solution that maintains measurement accuracy without requiring complex active control systems or sophisticated mechanisms.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

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 allows for improved measurement accuracy and increased movable range, enabling the precise measurement of multiple workpieces by effectively cancelling eccentric loads and minimizing the impact of center of gravity fluctuations.

Implementation Method 1

eccentric load cancelling means configured to cancel an eccentric load caused by the indexing of the index table

Methodology Applied

Scientific EffectEccentric load cancellation: Gravitation

Implementation Method 2

a detector including a probe to be brought into contact with the workpiece placed on the rotary table, the detector configured to detect a displacement of the probe

Methodology Applied

Scientific EffectMechanical contact displacement detection:

Implementation Method 3

the rotary table has a centering mechanism configured to align a center axis of the workpiece and the rotation center axis

Methodology Applied

Scientific EffectMechanical alignment:

Data Source

PatentUS11525660B2Surface shape measuring device and surface shape measuring method

Publication Date: 2022.12.13 TOKYO SEIMITSU CO LTD

AI summary

When an index table is installed on a rotary table in a surface shape measuring device, deterioration in measurement accuracy can be suppressed. The surface shape measuring device includes: a rotary table which is configured to place a workpiece thereon and to be freely rotatable around a rotation center axis; and a detector configured to detect a displacement of a probe brought into contact with the workpiece. The rotary table has a centering mechanism configured to align a center axis of the workpiece and the rotation center axis. An index table freely detachably mounted on the rotary table is provided, the index table configured so as to be able to perform indexing along a first axis and a second axis which are perpendicular to the rotation center axis. Eccentric load cancelling means configured to cancel an eccentric load caused by the indexing of the index table is provided.