Workpiece Holder Claw Position Sensing Without Electric Power

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Solution Overview

Problem

Existing workpiece holders for machine tools and machining centers require an electric power supply for proximity sensors to detect claw positions, which complicates design and manufacturing, especially when the holder is rotatably supported.

Innovation Solution

A pneumatic system using a pneumatic valve and flow control element, actuated by a contoured surface, detects claw positions without the need for an electric power supply, relying on pressurized air and elastic means to switch between closed and venting positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If proximity sensors are used to detect claw positions, then measurement precision is improved, but device complexity and manufacturing difficulty increase due to the need for electric power supply

Engineering Contradiction:
Improveclaw position detection precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the electrical proximity sensor system with a purely mechanical detection system. Magnetic locators fixed to the claws interact with reed switches mounted on the cylindrical chamber, eliminating the need for electric power supply while maintaining reliable position detection. This mechanical substitution resolves the contradiction by removing complex electrical components while preserving measurement functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic locators as intermediary elements that mediate between the moving claws and the stationary reed switches. These magnetic locators carry magnetic information without requiring electrical power, enabling the reed switches to detect claw positions passively. This intermediary mechanism resolves the contradiction by providing precise detection without the complexity of powered sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If electrically powered proximity sensors are installed, then detection reliability is improved, but ease of manufacture deteriorates due to power supply requirements

Engineering Contradiction:
Improveposition detection reliabilityVSAvoidmanufacturing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces electrical sensors with a mechanical-magnetic detection system using reed switches and magnetic locators. This substitution eliminates the need for electrical power supply infrastructure, simplifying manufacturing while maintaining reliable detection. The reed switches are passive components that respond to magnetic fields, requiring no power connections or electrical infrastructure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The detection system is designed to be self-powered through the interaction between magnetic locators and reed switches. The magnetic field generated by the locators automatically actuates the reed switches without requiring external power supply or complex wiring. This self-service mechanism improves ease of manufacture by eliminating power supply requirements while maintaining reliable detection.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If pneumatic systems are used for claw actuation, then ease of operation is improved, but device complexity increases when adding detection systems

Engineering Contradiction:
Improveclaw actuation easeVSAvoiddetection system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the detection system with the existing pneumatic chamber structure. Reed switches are mounted directly on the cylindrical chamber that already houses the pneumatic actuation system. This integration combines two functions (actuation and detection) into a unified structure, maintaining ease of pneumatic operation while minimizing additional complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces complex electrical detection systems with a simple mechanical-magnetic system using reed switches and magnetic locators. This substitution maintains ease of operation by keeping the system responsive to mechanical movements while reducing overall complexity. The magnetic field interaction requires no additional control electronics or power management.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 pneumatic system provides a reliable and precise method for detecting claw positions, eliminating the need for electric power and simplifying implementation, making it suitable for various applications.

Implementation Method 1

a flow control element (45) which can move between a closed position and a venting position of the circuit C under the control of a contoured surface (48) which can move in correlation with the movement of the claws (32, 34) and actuates for opening/closing the flow control element (45) by cam action

Methodology Applied
Scientific EffectCam action: Cam

Implementation Method 2

said pneumatic valve (44) being provided with elastic means adapted to return the flow control element (45) in its initial position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3735335B1Workpiece holder for machine tools and machining centers, provided with a system for detecting the position of the claws
Publication Date: 2023.07.26 BRONZINO PIER MAURO
  • EP3735335B1 patent drawingFigure 1~2
  • EP3735335B1 patent drawingFigure 3
  • EP3735335B1 patent drawingFigure 4~5

AI summary

A workpiece holder for machining centers, comprising a body (12), at least one claw (32, 34) which can move with respect to the body (12) between two stroke limit positions under the control of actuation means (19), sensor means adapted to detect the stroke limit positioning of the claw (32, 34); the sensor means comprise a pneumatic valve (44) which controls a pressurized air circuit (C) provided in the body (12) and equipped with a flow control element (45) which can move between a closure position and a venting position of the circuit (C) under the control of transmission means (48) operatively connected to the claw (32, 34), the transmission means (48) causing the switching between the closure position and the venting position when the claw (32, 34) reaches the stroke limit positions.