Expandable Slit Sheet Dunnage Conversion Tensioning

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Solution Overview

Problem

Existing packaging materials lack an efficient method to convert paper sheets into a low-density, expandable dunnage product for effective cushioning and void-filling during shipping, which is both eco-friendly and easy to use.

Innovation Solution

A dunnage conversion apparatus that utilizes a roll of expandable slit sheet material, applying a stretching force with a tensioning device, including a friction member and force spring, to expand the material from an unexpanded to an expanded state, forming a cushioning wrap material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stretching force is applied to expand the slit sheet material, then the material expands from unexpanded to expanded state, but the required stretching force increases as the roll decreases in diameter

Engineering Contradiction:

Improveconsistent expansionVSAvoidstretching force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The apparatus dynamically adjusts the stretching force by applying a constant force to the roll through a force application mechanism. This constant force compensates for the changing radius of the roll during expansion, ensuring consistent stretching force throughout the expansion process from unexpanded to expanded state.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses the roll's own weight and the force application mechanism to automatically maintain consistent stretching force. The force spring or weight-based mechanism self-adjusts to provide constant force throughout the expansion process without external intervention.

Inventive Principle:

Principle #25Self-service

2Quantity of substance

If the roll decreases in diameter during material withdrawal, then more material can be stored, but the stretching force required increases

Engineering Contradiction:

Improvematerial storage capacityVSAvoidstretching force

Core Design Contradiction:

Quantity of substanceVSForce

Solution Approach 1:

The apparatus dynamically compensates for the decreasing roll diameter by applying a constant force through a force application mechanism. This ensures that the stretching force remains consistent throughout the material withdrawal process, allowing the roll to decrease in diameter for increased storage capacity without requiring progressively more force.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The force spring or weight-based mechanism automatically adjusts to provide constant stretching force throughout the material withdrawal process. The system self-regulates to maintain consistent force application as the roll diameter decreases, enabling maximum material storage without increasing operational force requirements.

Inventive Principle:

Principle #25Self-service

3Device complexity

If manual stretching is used, then the apparatus is simpler, but the expansion is inconsistent and requires high force

Engineering Contradiction:

Improveapparatus structureVSAvoidexpansion consistency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The apparatus uses a self-regulating force application mechanism that automatically maintains consistent stretching force throughout the expansion process. The force spring or weight-based system self-adjusts to provide uniform force, eliminating the need for complex active control systems while ensuring reliable and consistent expansion from unexpanded to expanded state.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces complex active mechanical control systems with a simpler passive force application mechanism. The force spring or weight-based system automatically provides consistent stretching force without requiring motors, sensors, or active control, achieving reliable expansion consistency with minimal device complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 apparatus consistently and automatically expands the slit sheet material, reducing the required stretching force and maintaining pressure, resulting in a reliable and efficient cushioning solution for packaging.

Implementation Method 1

at least one force spring secured to the frame and the friction member. The force spring is configured to bias the friction member toward the roll of expandable slit sheet material in a direction perpendicular to the central axis

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

a tensioning device having a friction member abutting the roll of expandable slit sheet material

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS20240270529A1Apparatus and method for dispensing a cushioning wrap material

Publication Date: 2024.08.15 RANPAK CORP

AI summary

A dunnage conversion apparatus for dispensing a cushioning wrap material from a roll of expandable slit sheet material is described. The roll of expandable slit sheet material includes an expandable slit sheet material in an unexpanded state. The expandable slit sheet material is pulled from the roll of expandable slit sheet material and expanded to a pre-expanded state and an expanded state. To expand the expandable slit sheet material and form the cushioning wrap material, a stretching force is applied to the expandable slit sheet material in a stretching direction as it is pulled from the roll of expandable slit sheet material. Accordingly, the dunnage conversion apparatus includes a tensioning device for assisting in the application of such stretching force.