Crossbar Workpiece Transfer Apparatus with Linear Motor Drive

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Solution Overview

Problem

Conventional workpiece transfer apparatuses for press machines are limited in increasing workpiece transfer speed due to the weight of threaded shafts and racks, which cause vibrations and require lubrication that can contaminate products, while reducing their length limits the range of movement for workpiece retaining mechanisms.

Innovation Solution

A workpiece transfer apparatus with a crossbar unit that includes electric motor-driven pinion and rack gear mechanisms, along with a brake system using a friction element, allowing for lightweight, compact, and oil-free operation, enabling rapid and precise positioning of workpiece retaining devices without increasing the weight or size of the driving mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If threaded shafts and racks are used for driving workpiece retaining mechanisms, then the range of movement and positioning capability are improved, but the weight increases causing vibrations and requiring lubrication that contaminates products

Engineering Contradiction:
Improverange of movementVSAvoidweight of driving mechanism
Core Design Contradiction:
Length of moving objectVSWeight of moving object

Solution Approach 1:

The patent replaces the conventional threaded shaft and rack mechanism with a linear motor-driven system. The linear motor directly generates linear motion without requiring heavy mechanical transmission components, thereby eliminating the weight issue while maintaining the full range of movement capability. This substitution also eliminates the need for lubrication, preventing product contamination.

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

Solution Approach 2:

The patent changes the fundamental operating principle from mechanical transmission (threaded shaft) to electromagnetic direct drive (linear motor). This parameter change in the driving mechanism enables oil-free operation and reduces weight, while the controlled positioning capability is maintained through precise electromagnetic control of the linear motor.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If threaded shafts and racks are used for driving workpiece retaining mechanisms, then the range of movement is improved, but lubrication is required which contaminates products

Engineering Contradiction:
Improverange of movementVSAvoidproduct contamination
Core Design Contradiction:
Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the lubrication-dependent mechanical transmission system with a linear motor system that operates without lubricants. The linear motor generates motion through electromagnetic fields, eliminating the need for oil or grease that could contaminate products, while still achieving the required range of movement for workpiece retaining mechanisms.

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

3Weight of moving object

If the length of threaded shafts and racks is reduced to decrease weight, then the weight and size of driving mechanism are reduced, but the range of movement for workpiece retaining mechanisms is limited

Engineering Contradiction:
Improveweight of driving mechanismVSAvoidrange of movement
Core Design Contradiction:
Weight of moving objectVSLength of moving object

Solution Approach 1:

The patent substitutes the mechanical transmission system with a linear motor system where the stroke length is directly determined by the motor design rather than the length of mechanical components. This allows for a compact, lightweight motor while maintaining a long effective range of movement, as the linear motor can generate force throughout its entire stroke without requiring proportionally long mechanical transmission elements.

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

4Device complexity

If conventional mechanical driving mechanisms are used, then structural simplicity is maintained, but workpiece transfer speed is limited due to inertia forces

Engineering Contradiction:
Improvestructural simplicityVSAvoidworkpiece transfer speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The patent replaces the heavy mechanical transmission system with a linear motor system that has significantly reduced moving mass. This reduction in inertia allows for much higher acceleration and deceleration rates, enabling faster workpiece transfer speeds while maintaining relatively simple overall system structure. The direct-drive nature of the linear motor eliminates complex mechanical linkages that would limit speed.

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

This configuration enhances workpiece transfer speed and production efficiency by reducing inertia forces and eliminating the need for lubrication, while allowing for precise and flexible positioning of workpiece retaining devices according to the size and shape of the workpiece.

Implementation Method 1

a linear motor (17) for allowing the workpiece retaining means (9) provided to at lease one crossbar (7) to be movable along a longitudinal direction of the crossbar (7)

Methodology Applied
Scientific EffectLinear motor: Linear Motor

Implementation Method 2

brake means acting in a path (or route) different from a path of the driving means, the brake means being capable of fixing and releasing a position of the workpiece retaining means

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2377630B1Workpiece transfer apparatus for press machine and crossbar unit
Publication Date: 2016.02.10 AIDA ENGINEERING LTD
  • EP2377630B1 patent drawingFigure 1
  • EP2377630B1 patent drawingFigure 2
  • EP2377630B1 patent drawingFigure 3

AI summary

Provided is a workpiece transfer apparatus for a press machine including: a workpiece retaining unit which is supported by a crossbar extending to be approximately orthogonal to a workpiece transfer direction, and is capable of retaining and releasing a workpiece; a guiding unit for supporting and guiding the workpiece retaining means so that the workpiece retaining means is slidable along a longitudinal direction of the crossbar; a driving unit for driving the workpiece retaining means supported and guided by the guiding means so that the workpiece retaining means is moved along the longitudinal direction of the crossbar; and a brake unit acting in a path different from a path of the driving means, the brake means being capable of fixing and releasing a position of the workpiece retaining means with respect to the longitudinal direction of the crossbar.