Thermoformed Snack Container Seal for Lightweight Leak Prevention
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Solution Overview
Problem
Lidded thermoformed containers face challenges in achieving a reliable liquid-proof and airtight seal due to gauge and mold variations during manufacturing, leading to issues with capping force, container stability, and leakage, especially when made from lightweight materials.
Innovation Solution
The development of a container with a cup portion and lid thermoformed from sheet stock with a maximum gauge of less than 35 mils, featuring a substantially elastic hinge and interference-fit seal, which allows for a secure and leak-tight closure without requiring heavy gauge materials, and includes design features for improved stability and ease of use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lightweight sheet stock (less than 35 mils) is used for thermoformed containers, then material usage and container weight are reduced, but achieving a reliable liquid-proof and airtight seal becomes difficult due to gauge and mold variations
Solution Approach 1:
The patent changes the geometric parameters of the sealing surfaces, specifically creating a recessed sealing surface in the base and a corresponding protruding sealing surface on the lid. This geometric modification allows the sealing surfaces to cooperate effectively even with lightweight materials (less than 35 mils) despite gauge and mold variations, achieving reliable liquid-proof and airtight seals without requiring heavy gauge materials
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a flexible hinge that attaches the lid to the base. This hinge acts as a mediator that absorbs dimensional variations and allows the lid to conform to the base's sealing surface, ensuring consistent seal quality even when using lightweight sheet stock with manufacturing tolerances
2Quantity of substance
If the lid is made of lighter sheet stock, then container weight is reduced, but the capping force required may crush the container
Solution Approach 1:
The patent modifies the geometric parameters of the lid and base sealing surfaces to create an interference-fit sealing mechanism that requires minimal capping force. The recessed sealing surface in the base and protruding sealing surface on the lid are designed to mate precisely, allowing lightweight lid materials to form secure seals without requiring excessive closing force that would crush the container
3Ease of operation
If the lid is attached to the base with a hinge, then the lid remains readily available and will not be misplaced, but the weight of the lid may tip the container base on the counter-top
Solution Approach 1:
The patent employs a flexible hinge that allows the lid to move dynamically between attached and detached positions. The hinge is designed with sufficient flexibility to allow the lid to flop forward onto the counter-top, which actually enhances stability by creating a counterbalancing weight that prevents the container from tipping over
4Strength
If a stiff plastic hinge is used to attach the lid, then the lid remains secure to the base, but the hinge transmits torque due to lid weight and makes the container unstable on the counter-top
Solution Approach 1:
The patent changes the rigidity parameter of the hinge by using a flexible hinge design rather than a stiff plastic hinge. This flexible hinge reduces torque transmission to the container base, preventing instability on the counter-top while still maintaining secure attachment and durability through controlled flexibility that accommodates lid weight without creating destabilizing moments
Data Source
AI summary
A container that is a cup portion having a maximum gauge of less than 35 mils provided with a bottom panel, a sidewall and a sealing brim which defines an annular cup sealing surface; and a lid having a maximum gauge of less than 35 mils with a sealing rim defining an annular lid sealing surface; wherein the cup portion and lid portion are thermoformed such that the annular cup sealing surface and the annular lid sealing surface cooperate to form a seal extending around the assembled container and wherein the container does not leak when tested using the Leak Test Method 1.