Magnetic Chuck Piston Control for Single Workpiece Conveyance

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Solution Overview

Problem

Existing magnetic chucks struggle to safely transport a single workpiece from a stack without it falling due to acceleration or vibration, as the magnetic force adjustment for retaining a single workpiece is not sufficient for secure transport.

Innovation Solution

The magnetic chuck is designed to control the first piston to three positions: no magnetic force, maximum magnetic force, and a predetermined magnetic force smaller than the maximum, allowing for the selective attraction and secure transport of a single workpiece from a stack.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the magnetic force is adjusted to retain exactly a single workpiece, then only one workpiece is retained among stacked workpieces, but the workpiece may fall during conveyance due to acceleration or vibration

Engineering Contradiction:
Improvenumber of workpieces retainedVSAvoidworkpiece retention during conveyance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The magnetic chuck employs a dynamic magnetic force adjustment mechanism through a piston assembly that can be positioned at multiple discrete locations. The piston is movable between a first position (maximum magnetic force for secure conveyance), a second position (predetermined magnetic force for selective single workpiece retention), and a third position (no magnetic force for workpiece release). This dynamic positioning allows the system to adapt magnetic force levels to different operational phases, resolving the contradiction between retaining only one workpiece and ensuring reliable retention during conveyance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the magnetic force parameter by altering the physical position of the piston assembly relative to the workpiece. By controlling the piston to be at different distances from the workpiece surface, the magnetic field strength is varied: maximum force when closest (for conveyance), predetermined force at intermediate position (for selective retention), and zero force when retracted (for release). This parameter change approach enables the system to overcome the fixed magnetic force limitation and achieve both selective retention and secure conveyance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the magnetic force is increased to prevent workpiece falling during conveyance, then the workpiece is securely retained, but multiple workpieces are retained simultaneously from the stack

Engineering Contradiction:
Improveworkpiece retention during conveyanceVSAvoidnumber of workpieces retained
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system dynamically adjusts magnetic force by positioning the piston at different locations. During the conveyance phase, the piston is positioned at the first location to generate maximum magnetic force, ensuring secure retention of the workpiece even under acceleration or vibration. During the selection phase, the piston is positioned at the second location to generate only predetermined magnetic force, allowing only the top workpiece to be retained. This dynamic control resolves the contradiction between secure conveyance and selective retention.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The magnetic force is applied periodically in two distinct phases: a first phase with maximum magnetic force during conveyance to ensure secure retention, and a second phase with predetermined magnetic force during workpiece selection to retain only one workpiece. The piston assembly transitions between positions to implement this periodic action, allowing the system to achieve both objectives at different times in the operational cycle.

Inventive Principle:
Principle #19Periodic action

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 enables the safe transportation of a single workpiece by maintaining the maximum magnetic force during transport, preventing the workpiece from falling even under conditions of high acceleration or vibration.

Implementation Method 1

a magnetic chuck that attracts and retains a workpiece by the magnetic force of a permanent magnet

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP4286112B1Magnetic chuck
Publication Date: 2025.03.05 SMC CORP
  • EP4286112B1 patent drawingFigure 1
  • EP4286112B1 patent drawingFigure 2
  • EP4286112B1 patent drawingFigure 3

AI summary

A magnetic chuck includes a first cylinder (12) and a second cylinder (64) that are arranged in series with each other. A first piston (28) of the first cylinder includes a permanent magnet (36), and a piston rod (44) connected to the first piston is inserted into a second piston (76) of the second cylinder. A stopper (90) that can abut against the second piston is fixed to the piston rod. The position of the stopper can be changed relative to the piston rod.