Gluing Unit With Flexible Counter-Surface For Uniform Bag Adhesion

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Solution Overview

Problem

Existing gluing units in sack manufacturing face challenges in ensuring an even and continuous application of glue to bag components, particularly with the use of starch glues and varying material thicknesses.

Innovation Solution

A gluing unit with a counter-surface composed of flexible material and resilient elements, featuring a segmented active surface with movable bands that apply force uniformly across the bag components, allowing for adjustable contact pressure and mobility to accommodate different thicknesses and angles, and incorporating holding means to counteract the gluing force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a stationary nozzle bar is used for gluing bag components, then the device structure is simple, but the glue application is not uniform and continuous due to varying relative speeds

Engineering Contradiction:
Improveuniformity of glue applicationVSAvoidcomplexity of gluing device
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The nozzle bar is made movable relative to the bag components, allowing dynamic adjustment of the gluing position to maintain optimal relative speed and ensure uniform glue application. The movable nozzle bar can be adjusted in the running direction to compensate for speed variations and maintain consistent gluing quality.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If a rigid counter-layer is used to press bag components against the nozzle bar, then the structure is stable, but the bag components may be crushed and cannot accommodate varying thicknesses

Engineering Contradiction:
Improvecontact pressure uniformityVSAvoidaccommodation of varying thicknesses
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The counter-layer is made of flexible material that can deform to accommodate varying bag component thicknesses while maintaining stable contact pressure. The flexible nature allows adaptation to different geometries without crushing the components, ensuring both precision and versatility.

Inventive Principle:
Principle #30Flexible shells and thin films

3Reliability

If starch-based adhesives are used for gluing, then the adhesive performance is good, but the glue is easily displaced during the gluing process

Engineering Contradiction:
Improveadhesive bonding strengthVSAvoidglue position stability
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The bag components are pre-positioned and held firmly against the nozzle bar before glue application. This preliminary positioning ensures that the starch-based adhesive remains in place during application and subsequent processing, preventing displacement while maintaining bonding strength.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If multiple different dies are used to produce different bag formats, then the manufacturing precision for each format is high, but the device complexity and die inventory requirements increase

Engineering Contradiction:
Improvebag format accuracyVSAvoidnumber of different dies
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The movable nozzle bar with adjustable positioning can accommodate multiple bag formats using a single gluing device. By adjusting the nozzle bar position and the counter-layer configuration, the same device can handle different bag sizes and formats, eliminating the need for multiple specialized dies while maintaining manufacturing precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 ensures a uniform and continuous application of glue, preventing glue displacement and accommodating varying bag component thicknesses, while minimizing mechanical stress and allowing for precise control over the gluing process.

Implementation Method 1

The counter-surface (5) is designed to be at least partially made of flexible material. In addition to, or instead of, flexibility—which at least prevents the bag components from being crushed by an overly rigid counter-layer, spring elements can also be incorporated into the counter-layer. These spring elements provide additional restoring force on top of the softness of the flexible parts.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3254767B1Bottomer for manufacturing sacks
Publication Date: 2020.03.11 WINDMOELLER & HOELSCHER GMBH
  • EP3254767B1 patent drawingFigure 1~2
  • EP3254767B1 patent drawingFigure 3~5
  • EP3254767B1 patent drawingFigure 6

AI summary

Bottom-laying device for the production of bags, preferably cross-bottom valve bags (18), which includes at least one gluing unit (1) that applies glue to the bag components (2). The gluing unit (1) includes a nozzle bar (4) which has at least one nozzle for extruding glue onto the bag components (2), and a counter-position (5) which applies a force to the bag components (2) against the nozzle bar (4).