Bottle Blowing Mold Opening Linkage Replacing High-Wear Spatial Cams

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Solution Overview

Problem

Existing bottle blowing machines face challenges with high design and machining accuracy requirements for cylindrical spatial cams, difficult installation and positioning, easy rotor damage, and large pressure stress due to point contact, leading to wear and instability.

Innovation Solution

A single mold opening mechanism utilizing a planar four-bar linkage and spatial four-bar linkage mechanisms, with a mold opening/closing rotating shaft, bottom mold swing arm, and crank-slider mechanism, to achieve precise coordination of mold movements, reducing dynamic load and wear, and enhancing stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a cylindrical spatial cam and spatial linkage are used to realize bottom mold swinging and lifting, then the structure is simple with few moving parts, but the design and machining accuracy requirements for the cam flange or groove profile are high, and installation and positioning are difficult

Engineering Contradiction:
Improvestructure complexityVSAvoidcam profile machining accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces the cylindrical spatial cam mechanism with a planar four-bar linkage mechanism. This substitution eliminates the complex cam profile machining requirements while achieving the same functional outcome of coordinating side mold opening/closing with bottom mold swinging and lifting. The planar linkage uses standard mechanical components with simpler manufacturing tolerances.

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

Solution Approach 2:

The patent divides the bottom mold movement into two independent but coordinated mechanisms: a spatial four-bar linkage for swinging motion and a planar crank-slider mechanism for lifting motion. This segmentation allows each mechanism to be optimized independently, reducing the overall manufacturing precision requirements compared to a single integrated cam system.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a cylindrical spatial cam is used, then the structure is simple, but the contact surface of the rotor and cam profile forms point contact, resulting in large pressure stress and easy damage or wear

Engineering Contradiction:
Improvestructure complexityVSAvoid rotor and cam profile durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces spherical surfaces at the connection points of the spatial linkage mechanism. These spherical joints distribute the contact stress over a larger surface area compared to point contact, reducing pressure stress and preventing easy damage or wear of mechanical components while maintaining structural simplicity.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Volume of stationary object

If the cam pressure angle is large due to space limitations, then the mechanism fits in limited space, but the rotor is easy to damage or the cam profile surface is easy to wear

Engineering Contradiction:
Improvemechanism space sizeVSAvoid rotor and cam profile durability
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The patent transitions from a planar cam mechanism to a spatial four-bar linkage mechanism with spherical joints. This dimensional change allows the mechanism to achieve the required motion coordination within limited space while maintaining more favorable pressure angles through the three-dimensional configuration, thereby improving reliability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4238738B1Single mold opening mechanism of a bottle blowing machine
Publication Date: 2025.07.09 JIANGSU NEWAMSTAR PACKAGING MACHINERY
  • EP4238738B1 patent drawingFigure 1
  • EP4238738B1 patent drawingFigure 2
  • EP4238738B1 patent drawingFigure 3

AI summary

Disclosed in the present invention is a single mold opening mechanism of a bottle blowing machine, comprising: a mold frame support, a fixed side mold, a mold opening/closing rotating shaft that can be rotated about a first axis line and is provided on the mold frame support, a mold opening/closing rotor arm, a movable side mold, a bottom mold support that can be rotated about a second axis line and is provided on the mold frame support, a bottom mold guide track, a bottom mold, a bottom mold connecting rod, a bottom mold swing arm, a bottom mold swing rod, a space connecting rod, a bottom mold crank, and a bottom mold pull rod. The first axis line and the second axis line are respectively located on two sides of a mold closing center line; when the bottle blowing machine performs mold opening, a mold opening/closing rotating shaft is configured to drive the movable side mold to rotate away from the fixed side mold, and to drive the bottom mold support to move toward the opening of the opened mold; and the bottom mold support is configured to drive the bottom mold to descend. The single mold opening mechanism of the bottle blowing machine of the present invention can precisely control the movement patten of the movable side mold and the bottom mold, has a simple structure and small dynamic load, and can effectively reduce the vibration and impact of the mechanism, reduce the wear of parts, improve the movement stability and reliability of the blow molding machine, and improve the high-speed performance of the whole machine.