Modular Plastic Conveyor Belt Hinges for Weld-Line Strength

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Solution Overview

Problem

Modular plastic conveyor belts often break at weld lines due to concentrated belt tension in symmetrical hinge elements, particularly in turns, as the weld lines form between rod holes and the ends of the hinge elements, leading to structural weakness.

Innovation Solution

The conveyor belt module design features hinge elements with narrowed portions in specific regions to redirect weld lines away from the belt's pull line, using asymmetrical side wall configurations to manage tension more effectively, with elongated rod holes allowing the belt to navigate turns and incorporate drive sprockets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If symmetrical hinge elements are used, then manufacturing is simplified, but weld lines form at critical locations causing structural weakness

Engineering Contradiction:

Improvehinge element symmetryVSAvoidbelt tension resistance

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The hinge element is designed with asymmetrical geometry where the cross-sectional width varies along its length. Specifically, the portion of the hinge element adjacent to the rod hole has a different width than the distal portion, creating an asymmetric shape that redirects weld lines away from the critical pull line region while maintaining manufacturability through injection molding.

Inventive Principle:

Principle #4Asymmetry

2Ease of manufacture

If weld lines form at the pull line, then manufacturing is straightforward, but the belt breaks under tension

Engineering Contradiction:

Improveweld line positioningVSAvoidbelt integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The hinge element incorporates localized geometric variations in specific regions. The cross-sectional width is deliberately varied at different locations along the hinge element, creating zones of different structural properties. This local quality modification ensures that weld lines form in non-critical areas while the critical pull line region maintains optimal strength characteristics.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If elongated rod holes are used, then the belt can navigate turns, but manufacturing complexity increases

Engineering Contradiction:

Improveturn navigation capabilityVSAvoidrod hole geometry

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The rod holes are designed with elongated and curved geometries rather than simple circular cross-sections. This curvature and elongation allow the hinge elements to accommodate angular deviations and enable the conveyor belt to navigate turns while maintaining proper alignment and tension distribution throughout the belt structure.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS12404109B2Conveyor belt and modules

Publication Date: 2025.09.02 LAITRAM LLC

AI summary

A modular plastic conveyor belt constructed of injection-molded belt modules having narrowed portions either above or below rod holes in hinge elements. The narrowed portions are formed by a restricted-flow region in an injection-mold cavity that ensures that weld lines in the hinge elements are angled off the pull line of the conveyor belt.