Resealable Can Lid with Snap-Lock Seal and Tear Notch

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Solution Overview

Problem

Existing resealable can lids face challenges in ease of handling, gas-tightness, and usability in conventional can filling systems, failing to maintain high internal pressures during pasteurization and requiring significant opening and reclosing forces, which limits their industrial application.

Innovation Solution

A resealable can lid design featuring a circumferential tear notch with a collar part and lid receiving part made of different plastic materials, forming a snap-lock connection and utilizing a pull tab with varying elasticity to facilitate easy opening and reclosing, while ensuring gas-tightness through elastic sealing materials and buckling spring elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a prefabricated plastic closure part is inserted into a punched opening in the metallic can lid, then the opening can be sealed, but the device complexity increases and manufacturing precision requirements increase

Engineering Contradiction:
Improvesealing reliabilityVSAvoidclosure structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the closure part directly into the can lid as a single integrated structure rather than using separate prefabricated components. The closure part is formed as one piece with the lid, eliminating the need for separate insertion and assembly operations, thereby reducing device complexity while maintaining sealing reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The closure part is divided into functional segments: a lid portion integrated with the can lid, a closure element that seals the opening, and a tear-off tab for opening. This segmentation allows each component to perform its specific function while being manufactured as an integrated unit, reducing overall complexity.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If conventional tin cans are torn open via a tab, then the opening can be made, but sharp edges are produced that reduce ease of operation

Engineering Contradiction:
Improveopening easeVSAvoidsharp edges
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A tear notch is pre-formed in the closure part at a controlled location. This preliminary action guides the tearing process and eliminates the need for sharp edges to initiate the opening. The tear notch is positioned to allow clean tearing without producing harmful sharp edges on the can lid or closure part.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the closure part is designed to engage via snap-lock connection, then the seal is secure, but the opening and reclosing forces increase

Engineering Contradiction:
Improveseal securityVSAvoidopening and reclosing force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The snap-lock connection is designed with localized engagement features at specific positions on the closure part and corresponding features on the lid. This localized approach provides secure sealing at the critical sealing interface while minimizing the overall force required for opening and reclosing by concentrating the locking action at optimal points.

Inventive Principle:
Principle #3Local quality

4Reliability

If elastic sealing materials are used to ensure gas-tightness, then the seal maintains integrity under pressure, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvegas-tightnessVSAvoidseal interface precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent uses elastic sealing materials with specific viscoelastic properties that allow them to deform and conform to the sealing interface under pressure. This parameter change in material properties enables the seal to maintain gas-tightness without requiring extremely high manufacturing precision, as the material itself accommodates minor variations through elastic deformation.

Inventive Principle:
Principle #35Parameter changes

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 design allows for a compact, liquid-tight, and gas-tight reclosable unit that can be opened with low force, maintains gas-tightness under high pressures, and enables one-handed operation, ensuring the can contents' shelf life and compatibility with conventional can filling systems.

Implementation Method 1

a buckling spring element (22), in particular comprising at least one film hinge, which holds this cover part in the open position when the collar part (5) representing the cover part is pivoted open through a pivoting angle of advantageously more than 90°

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a sealing snap-lock connection with a circumferential coupling rib (9) and a complementary shaped recess (12) is formed between the collar part (5) and the lid receiving part (10)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2354022B1Can lid and method for manufacturing a can lid
Publication Date: 2012.12.26 THIELEN KLAUS
  • EP2354022B1 patent drawingFigure 1~2
  • EP2354022B1 patent drawingFigure 3
  • EP2354022B1 patent drawingFigure 4

AI summary

The lid (1) has an opening area (11) designed as a cover plate and connected with a flange part (5) made from plastic material. The flange part is connected with a cover retaining part connected with a lid surface. The flange part overlaps the retaining part, and a snap-locking connection with a dome fin and a recess is formed between the flange and retaining parts. A tension plate (15) is fastened to a fixing area of the flange part at an outer side of the retaining part. A two-armed lever is designed for breaking a tearing notch from a partial-circumferential area of the flange part. An independent claim is also included for a method for manufacturing a can lid.