Variable Tension Film Dispenser With Interlocking Roll Control

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Solution Overview

Problem

Existing stretch wrap dispensers rely solely on friction to regulate film tension, which is inadequate as the required friction changes significantly with roll diameter, leading to functional issues when the roll is almost used up or too large.

Innovation Solution

A combination of ridges and slots or protrusions on a mandrel and flexible skin, which interlock when squeezed, providing a locking mechanism to stop the roll without excessive force, independent of roll size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If friction-based tension control is used, then film tension can be regulated, but the required friction changes significantly with roll diameter making it non-functional across different roll sizes

Engineering Contradiction:

Improvefunctional performance across different roll diametersVSAvoidsqueezing force required

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent changes the control mechanism from friction-based to interlocking-features-based. The mandrel includes protrusions and the skin includes slots that interlock to provide tension control, eliminating dependence on friction coefficients that vary with roll diameter. This allows consistent operation across different roll sizes without requiring extraordinary squeezing force.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If friction is increased to stop small rolls, then small rolls can be controlled, but excessive squeezing force is required for large rolls

Engineering Contradiction:

Improveability to stop rollVSAvoidsqueezing action required

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent segments the continuous friction interface into discrete interlocking features (protrusions on mandrel and slots in skin). These segmented features engage at specific points to provide reliable roll stopping without requiring excessive distributed squeezing force across the entire contact surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interlocking features act as intermediaries between the mandrel and skin, transferring rotational control forces efficiently. The protrusions and slots engage to directly transmit stopping forces without relying on friction alone, reducing the overall squeezing force required while maintaining reliable roll control.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 interlocking mechanism ensures consistent film tension control across varying roll diameters, eliminating the need for excessive squeezing and improving usability.

Implementation Method 1

A combination of ridges and slots or protrusions on a mandrel and flexible skin, which interlock when squeezed, providing a locking mechanism to stop the roll without excessive force

Methodology Applied

Scientific EffectMechanical interlocking: Mechanical Fastener

Implementation Method 2

flexible skin, which interlock when squeezed

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12441569B2Variable tension film dispenser with locking feature

Publication Date: 2025.10.14 GLOBAL FILM SOURCE LLC

AI summary

A variable tension control film dispenser with a locking mechanism that is manually activated by squeezing pressure on the outside of the skin against a mandrel or extended core.