Plastic Container Hinge Pin Lock with Living Hinge Tab

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Solution Overview

Problem

Molded plastic containers with snap-in plastic hinge lids lack sufficient rigidity and tamper resistance, which are essential for industrial applications, and metal hinge pins, while providing these features, are costly, difficult to recycle, and pose assembly and safety issues.

Innovation Solution

A molded plastic container with a hinge pin lock featuring a locking tab connected by a living hinge, which is molded with the container, and includes a channel with engagement structures to secure the hinge pin, providing enhanced rigidity and tamper resistance while using all-plastic materials for easy recyclability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal hinge pins are used to secure the lid, then rigidity and tamper resistance are improved, but cost and recyclability worsen

Engineering Contradiction:

ImproverigidityVSAvoidcost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces expensive metal hinge pins with inexpensive plastic hinge pins that are molded as integral parts of the lid. This substitution maintains the functional requirements while significantly reducing material cost and eliminating the need for separate fastening components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent employs a composite construction where plastic hinge pins work in conjunction with a locking tab mechanism featuring hooks and engagement structures. This combination of plastic components achieves metal-level security and rigidity while maintaining the benefits of plastic material such as low cost and recyclability.

Inventive Principle:

Principle #40Composite materials

2Reliability

If metal hinge pins are used to secure the lid, then tamper resistance is improved, but ease of assembly and safety worsen

Engineering Contradiction:

Improvetamper resistanceVSAvoidease of assembly

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The plastic hinge pins are designed as integral parts of the lid that self-align and snap into place within the container's pin channels. The locking tab with its pivotable hooks automatically engages with the container body, eliminating the need for separate assembly tools or complex fastening procedures while maintaining secure attachment.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces the traditional mechanical metal pin insertion system with a plastic snap-fit mechanism assisted by a locking tab. This substitution simplifies the assembly process from a multi-step metal fastening operation to a single snap-in action that automatically locks into place.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If simple snap-in plastic hinges are used, then ease of manufacture is improved, but rigidity and tamper resistance worsen

Engineering Contradiction:

Improveease of manufactureVSAvoidrigidity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The lid structure is divided into functional segments: the integral plastic hinge pins for basic attachment, and the separate locking tab mechanism with multiple hooks for enhanced security. This segmentation allows each component to be optimized for its specific function while maintaining overall structural integrity and rigidity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The locking tab introduces a new dimensional aspect to the hinge mechanism by adding a pivotable locking dimension perpendicular to the basic hinge motion. This additional degree of freedom with the pivotable tab and its hooks provides enhanced rigidity and tamper resistance without complicating the fundamental snap-in assembly process.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 maintains the security and automated assembly benefits of metal hinge pins while reducing costs and environmental impact by using integrated plastic hinge pins, ensuring secure and recyclable containers with improved rigidity and tamper resistance.

Implementation Method 1

a locking tab molded with an upper rim of the container and connected to the upper rim by a living hinge. The locking tab is pivotable from an open position to a locked position.

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8752727B2Container with hinge pin lock

Publication Date: 2014.06.17 MONOFLO INT

AI summary

A hinge pin lock for a molded plastic container includes a locking tab molded with an upper rim of the container and connected to the upper rim by a living hinge. The locking tab is pivotable from an open position to a locked position. A channel is formed in the upper rim and is sized to receive a hinge pin of a container lid. The channel includes engagement structure that secures the locking tab in the locked position.