Horizontal Axis Compression Molding Machine with Cam-Driven Sequential Mold Control

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Solution Overview

Problem

Existing compression molding machines for plastic closure shells and sealing liners are inefficient due to their vertical axis turret design, which limits the flexibility and speed of mold opening and closing processes.

Innovation Solution

A compression molding machine with a wheel mounted for rotation around a horizontal axis, featuring angularly spaced molds with cam mechanisms for sequential movement between open and closed positions, utilizing a cam displacement wheel to rapidly move mold segments and a spring-biased latch for excess force management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a vertical axis turret design is used for compression molding machines, then the machine structure is simplified, but the speed and flexibility of mold opening and closing are limited

Engineering Contradiction:
Improvemold opening and closing speedVSAvoidmachine structure complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent inverts the conventional vertical axis turret design by using a horizontal axis rotating wheel. This inversion allows the mold segments to move radially inward and outward more rapidly, significantly increasing the speed of mold opening and closing while maintaining a relatively simple overall structure through the use of cam mechanisms.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces dynamic elements through the cam mechanisms that control the radial movement of mold segments. The cams convert rotational motion into controlled radial movement, enabling rapid and precise opening/closing actions. The spring-biased latch also provides dynamic response to excess forces, enhancing the system's adaptability and speed.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If cam mechanisms are used to move mold segments between open and closed positions, then the control precision is improved, but the device complexity increases

Engineering Contradiction:
Improvemold position control precisionVSAvoidcam mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the mold into multiple segments (first and second mold segments) that can move independently radially. Each segment is controlled by its own cam mechanism, allowing precise control of each segment's position. This segmentation enables complex molding actions to be broken down into simpler, more controllable movements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cam mechanisms serve as intermediaries between the rotating wheel and the mold segments. The cams translate rotational motion into precise radial movements of the mold segments, providing controlled positioning without requiring complex direct drive mechanisms for each segment.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the second mold segments are moved rapidly from open to closed position, then the production speed is improved, but the load on guide bearings increases

Engineering Contradiction:
Improveproduction speedVSAvoidload on guide bearings
Core Design Contradiction:
ProductivityVSForce

Solution Approach 1:

The patent incorporates a spring-biased latch mechanism that provides cushioning against excess forces during the rapid movement of mold segments. The spring element absorbs shock and reduces peak loads on the guide bearings during high-speed operation, allowing rapid closing without proportionally increasing bearing loads.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The cam mechanisms are designed to control the timing and acceleration of mold segment movement dynamically. By optimizing the cam profiles, the system achieves rapid closing speeds while distributing forces more favorably over time, reducing instantaneous peak loads on the guide bearings compared to simpler mechanisms.

Inventive Principle:
Principle #15Dynamics

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 design enhances the efficiency of the molding process by allowing faster and more precise control over mold opening and closing, reducing the angular displacement required and minimizing load on guide bearings, thereby improving production speed and accuracy.

Implementation Method 1

Each of the second mold segments is movable by a cam radially with respect to the associated first mold segment between a radially inner closed position with the first mold segment for compression molding a plastic article, and a radially outer open position spaced from the associated first mold segment for removing a molded article from the mold and placing a mold charge into the mold.

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

The second cam portion in this aspect of the invention preferably is coupled to a spring-biased latch for release in the event of excess force applied to the second cam portion by the cam followers on the second mold segments.

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP1901904B1Compression molding machine
Publication Date: 2017.01.25 SACMI COOPERATIVA MECCANICI IMOLA SOC COOP ARL
  • EP1901904B1 patent drawingFigure 1
  • EP1901904B1 patent drawingFigure 2
  • EP1901904B1 patent drawingFigure 2A

AI summary

A machine for compression molding plastic articles includes an array of compression molds (52) mounted on a support (39) for movement through a defined mold path. A cam (126) is disposed adjacent to the support to engage the molds in sequence and move at least one segment of each mold between open and closed positions. The cam has a first portion (180) for opening the molds, a second portion (182) for closing the molds in sequence and a pivot (186) mounting the second cam portion to the first cam portion. A latch holds (200) the second cam portion in a first position for closing the molds in sequence, and is responsive to excess force on the second cam portion to release said second cam portion to pivot to a second position spaced from the path.