Self-Aligning Friction Puller With Venting for Injection Molds

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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 address misalignment and air flow issues.

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 hemispherical wedges with spherical contact surfaces that interface with corresponding hemispherical recesses in the mold plates. This spherical geometry allows the wedges to self-align and accommodate thermal expansion and manufacturing tolerances, eliminating misalignment issues while maintaining stable structural support during mold operations.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The friction puller design incorporates movable components including the hemispherical wedges that can adjust their position dynamically. The wedges are free to move within the deformable jacket, allowing real-time adaptation to alignment variations caused by thermal expansion, thereby maintaining consistent performance across different operating conditions.

Inventive Principle:

Principle #15Dynamics

2Force

If friction pullers create an air tight seal against pockets, then they provide friction grip, but air pressure differentials during mold close create force variations

Engineering Contradiction:

Improvefriction grip forceVSAvoidforce consistency

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The deformable jacket is designed with segmented or flexible construction that allows it to deform elastically during mold closure. This segmentation enables the jacket to accommodate air pressure differentials by deforming rather than maintaining a rigid air-tight seal, thus preventing random force variations while still providing adequate friction grip through controlled deformation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The deformable jacket changes its physical parameters (shape, volume, sealing characteristics) in response to air pressure differentials during mold operations. By allowing controlled deformation, the jacket adjusts its sealing properties dynamically, maintaining consistent friction grip force while accommodating pressure variations that would otherwise cause unreliable force output.

Inventive Principle:

Principle #35Parameter changes

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 stability during mold operations.

Implementation Method 1

The first passage allows the first substantially hemispherical wedge a first predetermined amount of lateral float relative to the bolt. The second passage allows the second substantially hemispherical wedge a second predetermined amount of lateral float relative to the bolt.

Methodology Applied

Scientific EffectLateral float:

Implementation Method 2

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. Likewise the deformable jacket preferably has at least one jacket vent notch disposed in a top surface of the deformable jacket.

Methodology Applied

Scientific EffectAir passage through vent relief notches:

Implementation Method 3

a deformable jacket that allows lateral float and includes vent relief notches for air passage

Methodology Applied

Scientific EffectControlled air flow through deformable jacket:

Data Source

PatentUS20090263528A1Injection mold friction puller

Publication Date: 2009.10.22 PROGRESSIVE COMPONENTS INT CORP

AI summary

A friction puller for an injection mold is disclosed. The friction puller has a bolt with a head portion and a threaded portion. The friction puller has first and second first substantially hemispherical wedges having a first and second passages running through them for the bolt and allow lateral float about the bolt. The friction puller also has a deformable jacket having a third passage running through is for the bolt and first and second substantially hemispherical cups for receiving the first and second substantially hemispherical wedges. The first hemispherical wedge can have a vent relief notch disposed in a top surface of the first hemispherical wedge. The deformable jacket can have a jacket vent notch 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.