Friction Puller with Hemispherical Wedges for Injection Mold Alignment

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Solution Overview

Problem

Existing friction pullers in injection molding devices face issues with misalignment due to thermal expansion and build tolerances, leading to inconsistent performance, and they do not allow for controlled air flow in and out of the mold pockets, resulting in undesirable force variations.

Innovation Solution

A self-aligning friction puller with hemispherical wedges and a deformable jacket that allows lateral float and includes vent relief notches for air passage, along with variable pitch threads and alignment indicators to ensure proper installation and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If friction pullers are fixed mounted into mold plates, then they provide stable structural support, but thermal expansion and build tolerances cause misalignment leading to inconsistent performance

Engineering Contradiction:
Improveperformance consistencyVSAvoidalignment accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent employs a hemispherical wedge section that fits into a corresponding hemispherical recess in the mold plate. This spherical interface allows the friction puller to self-align and accommodate thermal expansion and build tolerance variations, ensuring consistent performance across different operating conditions while maintaining stable structural support.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If friction pullers create an air tight seal against pockets, then they prevent air leakage, but air pressure differentials during mold closure create unpredictable forces

Engineering Contradiction:
Improveforce consistencyVSAvoidair pressure differential
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The deformable jacket in the friction puller incorporates a porous structure that allows controlled air flow through the seal. This prevents the formation of air pressure differentials during mold closure while maintaining adequate sealing to prevent air leakage, thereby ensuring consistent force application without unpredictable pressure effects.

Inventive Principle:
Principle #31Porous materials

3Strength

If friction pullers are designed to friction fit into pockets, then they provide secure mounting, but misalignment causes mold locking due to unequal force distribution

Engineering Contradiction:
Improvemounting securityVSAvoidforce distribution uniformity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The hemispherical wedge and recess interface enables the friction puller to self-center within the pocket, ensuring uniform force distribution across multiple pullers. This spherical mounting mechanism maintains secure friction fit while accommodating alignment variations, preventing mold locking caused by unequal force distribution.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Adaptability or versatility

If deformable jackets are used to accommodate misalignment, then lateral float is achieved, but air tight seals create vacuum or pressure issues

Engineering Contradiction:
Improvealignment accommodationVSAvoidair flow restriction
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The deformable jacket incorporates a porous structure that allows it to maintain its adaptability for accommodating misalignment and providing lateral float, while simultaneously permitting controlled air flow through the material. This prevents vacuum or pressure buildup issues that would occur with completely air-tight seals.

Inventive Principle:
Principle #31Porous materials

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 enables consistent performance by self-aligning with mold plates and controlling air flow, reducing force variations and improving operational reliability.

Implementation Method 1

The first hemispherical wedge has a least one vent relief notch disposed in a top surface of the first hemispherical wedge. The vent relief notch allows air to pass through during mold operation.

Methodology Applied
Scientific EffectAir flow through porous structure: Permeation

Implementation Method 2

When the bolt is tightened, the bolt head compresses the jacket lengthwise and the shank presses laterally on the jacket. The result is that under the load from the tightened bolt, the jacket has an increased diameter compared to when it is in an unloaded condition.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2282883B1Injection mold friction puller
Publication Date: 2013.03.13 PROGRESSIVE COMPONENTS INT CORP
  • EP2282883B1 patent drawingFigure 1~1A
  • EP2282883B1 patent drawingFigure 1B
  • EP2282883B1 patent drawingFigure 2

AI summary

A friction puller (100) for an injection mold is disclosed. The friction puller has a bolt (110) with a head portion (105) and a threaded portion (120). The friction puller has first and/or second first substantially- hemispherical wedges (130) having a first and/or second passages (150) running through them for the bolt and allow lateral float about the bolt. The friction puller also has a deformable jacket (160) having a third passage (190) running through is for the bolt and first and second substantially hemispherical cups (180) for receiving the first and second substantially hemispherical wedges. The first hemispherical wedge can have a vent relief notch (140) disposed in a top surface of the first hemispherical wedge. The deformable jacket (160) can have a jacket vent notch (140) disposed in a top surface of the deformable jacket. The bolt head and the jacket can have alignment indicator marks thereon. The bolt threads can have a variable pitch diameter.