Toggle Joint Sealing Adjustment in Injection Molding Machines

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Solution Overview

Problem

Long-term operation of injection molding machines leads to wear of seal members, necessitating frequent maintenance for replacement, which affects maintainability.

Innovation Solution

An injection molding machine design featuring a toggle mechanism with a bush, connection pins, a lubricant supply and discharge channel, a seal member, and an adjustable tightening mechanism to maintain sealing performance between the seal member and connection pin, allowing for improved maintainability by extending the seal member's lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the injection molding machine is operated for a long time, then productivity is improved, but the seal member is worn and maintenance frequency increases

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidseal member durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The pressing member is made adjustable to dynamically adapt to the wear of the seal member. By changing the pressing force according to the seal member's wear state, the system maintains optimal sealing performance throughout the operational lifecycle, extending the seal member's usable life and reducing maintenance frequency while ensuring continuous productive operation.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the seal member is tightened to improve sealing performance, then reliability is improved, but the device complexity increases due to the tightening mechanism

Engineering Contradiction:
Improvesealing performanceVSAvoidtightening mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The pressing force parameter is made adjustable through the tightening mechanism. By changing this parameter according to the seal member's wear state, optimal sealing performance is maintained. The mechanism allows parameter adjustment without requiring complex structural changes, balancing reliability improvement with device simplicity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the seal member is replaced frequently to maintain sealing performance, then reliability is maintained, but loss of time increases due to maintenance interruptions

Engineering Contradiction:
Improvesealing performanceVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The tightening mechanism allows for preliminary adjustment of the pressing force before the seal member becomes completely worn. By proactively adjusting the pressing force as wear progresses, the seal member's service life is extended, and maintenance is performed less frequently, reducing downtime and maintaining reliability.

Inventive Principle:
Principle #10Preliminary 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

The design enables adjustable sealing performance, allowing for prolonged use of seal members and reducing the frequency of maintenance, thereby enhancing the maintainability of the injection molding machine.

Implementation Method 1

a supply channel through which a lubricant is supplied to a bearing gap which is a gap between the bush and the connection pin

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

a seal member which seals the bearing gap

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP3640003B1Injection molding machine
Publication Date: 2021.04.28 SUMITOMO HEAVY IND LTD
  • EP3640003B1 patent drawingFigure 1
  • EP3640003B1 patent drawingFigure 2
  • EP3640003B1 patent drawingFigure 3

AI summary

An injection molding machine (10) includes a toggle mechanism (150) which connects a movable platen (120) and a rear platen (130) . The toggle mechanisms (150) includes a plurality of links (151, 152, 153, 154), a first connection portion (40) which connects the movable platen (120) and the link (152), a second connection portion (40) which connects the links (152, 153) to each other, and a third connection portion (40) which connects the rear platen (130) and the link (154). At least one of the first to third connection portions (40) includes a bush (55), a connection pin (50) which is inserted into the bush (55), a supply channel (62, 63) through which a lubricant is supplied to a bearing gap (65) which is a gap between the bush (55) and the connection pin (50), a discharge channel (67, 68) through which the lubricant is discharged from the bearing gap (65), a seal member (70) which seals the bearing gap (65), and a tightening mechanism (73, 73A) for tightening the seal member (70).