Reusable Envelope Closure Flap with Segmented Adhesive Layers

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Solution Overview

Problem

Existing envelope manufacturing processes produce single-use envelopes, which are inefficient for return shipping in e-commerce, requiring high production complexity and lower rates compared to traditional methods.

Innovation Solution

A reusable envelope design featuring a closing flap with two adhesive layers separated by a tear strip, protected by a sheet with aligned weakening lines, allowing for multiple uses without rework, and a machine for continuous production that deposits adhesive layers and protective sheets before forming the hose.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single adhesive layer is used on the closing flap, then the envelope can be manufactured simply, but it can only be used once and requires another envelope for returns

Engineering Contradiction:
ImprovereusabilityVSAvoidflap structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The adhesive layer is segmented into two separate adhesive layers (first and second adhesive layers) positioned at different locations on the closing flap. This segmentation allows the envelope to be closed twice - once using the first adhesive layer and once using the second adhesive layer - thereby enabling reusability without requiring a completely new envelope structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The weakening lines are pre-formed in the protective sheet at predetermined locations that align with the adhesive layers. This preliminary action allows the protective sheet to be easily torn away at the correct positions during use, exposing the adhesive layers in sequence and enabling the reusable functionality without complex mechanisms

Inventive Principle:
Principle #10Preliminary action

2Reliability

If protective means are applied after section separation, then the adhesive layer is protected, but the production process becomes more complex and slower

Engineering Contradiction:
Improveadhesive protectionVSAvoidproduction speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The protective sheet is applied to the closing flap before the envelope is separated into sections. This preliminary protection ensures that the adhesive layers are already protected during the separation process and subsequent handling, eliminating the need for additional protection steps after separation and maintaining high production speed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The protective sheet serves multiple functions simultaneously: it protects both the first and second adhesive layers, provides alignment references through its weakening lines, and facilitates easy removal during use. By combining these functions into a single component applied early in the process, the overall complexity and production time are reduced

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If traditional envelope manufacturing is used, then production is simple and fast, but the envelopes are single-use and inefficient for return shipping

Engineering Contradiction:
ImprovereusabilityVSAvoidmanufacturing process
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The adhesive system is segmented into two distinct adhesive layers positioned at different locations on the closing flap, allowing sequential use for initial mailing and return shipping. This segmentation enables reusability while maintaining compatibility with existing high-speed envelope manufacturing processes

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The protective sheet with pre-formed weakening lines is applied before section separation, establishing the reusable functionality and alignment references in advance. This preliminary action simplifies the overall manufacturing process by eliminating post-separation operations while enabling the envelope to be used multiple times

Inventive Principle:
Principle #10Preliminary action

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

Enables high-speed production of reusable envelopes that can be closed and opened multiple times, maintaining durability and handling thick contents, while simplifying the manufacturing process and increasing production efficiency.

Implementation Method 1

a first adhesive layer protected by protective means, a second adhesive layer protected by the protective means

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

the sheet comprising a third line of weakness aligned with the first line of weakness and a fourth line of weakness aligned with the second line of weakness

Methodology Applied
Scientific EffectStress concentration at perforation lines: Fracture Mechanics

Data Source

PatentEP4188819B1Reusable envelope with pre-cut closure flap, method and machine for manufacturing such an envelope
Publication Date: 2024.05.15 HOLWEG GRP
  • EP4188819B1 patent drawingFigure 1
  • EP4188819B1 patent drawingFigure 2
  • EP4188819B1 patent drawingFigure 3

AI summary

An envelope comprises a closure flap (14) for closing and opening (15) by folding over a first wall (11) of the envelope (1) and comprises, on an inner face (140), a first adhesive layer (141) protected by protection means (17) formed by a sheet, a second adhesive layer (142) protected by the protection means (17) and separated from the first adhesive layer (141) by a separation space (144), the flap (14) being pre-cut by a first and a second weakening line (181, 182) in the separation space (144), the sheet extending over the two adhesive layers (141, 142) and comprising a third weakening line (183) aligned with the first weakening line (181) and a fourth weakening line (184) aligned with the second weakening line (182). Method and machine for manufacturing such an envelope.