Flexible Elastomeric Mandrel for Wound Paper Core Segments

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current mandrels used in web material winding are complex, expensive, and heavy, making them difficult to operate at high speeds and prone to damage, while also limiting the variety of products that can be produced, and pose safety risks due to potential breakage and debris.

Innovation Solution

A flexible, lightweight mandrel made of plastic with a tubular shape that compresses radially to hold core segments securely, allowing for high-speed operation and easy switching between different production modes without the need for extensive modifications, and is designed to be durable and recyclable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If rigid mandrels with actuating elements are used to hold core segments securely, then core holding reliability is improved, but mandrel weight and complexity increase significantly

Engineering Contradiction:
Improvecore holding reliabilityVSAvoidmandrel weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces rigid mandrels with a flexible mandrel made of elastomeric material that conforms to the inner surface of core segments. This flexible shell approach eliminates complex actuating elements while maintaining secure core holding through elastic deformation and friction, directly resolving the contradiction between reliability and weight.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible mandrel is designed as a simple, inexpensive elastomeric component that can be easily replaced rather than maintained. This disposable approach eliminates the need for complex, expensive rigid mandrels with actuating elements, reducing both weight and complexity while maintaining functional reliability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Stability of the object's composition

If rigid mandrels are used to hold core segments, then structural stability is improved, but the ability to operate at high speeds with rapid acceleration is reduced

Engineering Contradiction:
Improvestructural stabilityVSAvoidoperating speed
Core Design Contradiction:
Stability of the object's compositionVSSpeed

Solution Approach 1:

The elastomeric flexible mandrel provides structural stability through its elastic properties while allowing rapid acceleration and deceleration. The flexible material can deform during sudden velocity changes without generating the inertial resistance characteristic of rigid mandrels, enabling high-speed operation.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical state of the mandrel from rigid to flexible elastomeric material. This parameter change allows the mandrel to adapt its stiffness dynamically - providing stability when needed while allowing rapid movement when required, thus resolving the contradiction between structural stability and operating speed.

Inventive Principle:
Principle #35Parameter changes

3Strength

If heavy rigid mandrels are used, then mandrel strength is improved, but the variety of products that can be produced is limited

Engineering Contradiction:
Improvemandrel strengthVSAvoidproduct variety
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The flexible elastomeric mandrel can be easily removed and replaced, allowing quick changeover between different core segment configurations. This flexibility enables the production of various product types including low density and low firmness rolls that would be impractical with heavy rigid mandrels, thus improving adaptability while maintaining sufficient strength.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces dynamic characteristics to the mandrel system through the use of flexible material that can adapt to different operational requirements. The mandrel can be quickly exchanged to match different product specifications, enabling versatile production across multiple product categories while maintaining the strength needed for each specific application.

Inventive Principle:
Principle #15Dynamics

4Strength

If rigid mandrels are used during web blowout or high speed crash, then structural integrity is maintained, but damage to other machine parts increases

Engineering Contradiction:
Improvestructural integrityVSAvoidmachine damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The flexible elastomeric mandrel absorbs impact energy during web blowout or high-speed crashes through elastic deformation rather than transmitting rigid forces to other machine parts. This flexibility prevents the propagation of harmful forces while maintaining sufficient structural integrity to protect the core segments.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent converts the potential harmful effect of impact forces into a beneficial elastic deformation of the flexible mandrel. The elastomeric material absorbs and dissipates crash energy, protecting both the core segments and other machine components from damage, thus turning a potentially harmful event into a protective mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

5Strength

If carbon fiber composite mandrels are used, then mandrel strength-to-weight ratio is improved, but safety risks increase due to breakage and debris

Engineering Contradiction:
Improvestrength-to-weight ratioVSAvoidsafety risks
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The elastomeric flexible mandrel replaces carbon fiber composite materials with a flexible polymer that does not fragment into dangerous debris upon failure. The elastomeric material deforms rather than shatters, eliminating the safety hazards associated with carbon fiber breakage while maintaining adequate strength through its elastic properties.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent uses elastomeric composite material that combines flexibility with sufficient strength, replacing the brittle carbon fiber composite. This elastomeric composite provides the necessary strength-to-weight ratio without the fragmentation and debris generation problems of carbon fiber, thus improving safety while maintaining performance.

Inventive Principle:
Principle #40Composite materials

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 flexible mandrel enables rapid accelerations and secure core segment holding, reducing cycle times and costs, while ensuring product reliability and safety by minimizing debris and allowing for a wider range of product variations without compromising quality.

Implementation Method 1

A flexible, lightweight mandrel made of plastic with a tubular shape that compresses radially to hold core segments securely

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2939970B1Method for producing rolls of wound paper using a flexible winding mandrel with core segments
Publication Date: 2019.12.25 PAPER CONVERTING MACHINE COMPANY ITALIA SPA
  • EP2939970B1 patent drawingFigure 1
  • EP2939970B1 patent drawingFigure 2
  • EP2939970B1 patent drawingFigure 3~4

AI summary

A flexible mandrel (30) is provided for holding cores or core segments (16') so that a roll of sheet material can be wound on the core segments in a winding machine. The mandrel and core segments are coupled through elastic interference between the mandrel and the core segments so that the core segments are arranged either adjacent to each other or spaced apart. A method for producing rolls of sheet material on the novel combination of mandrel and core segments feeds cores (16) in an apparatus, transversely cuts the cores to form portions of core or core segments (16'), feeds a flexible mandrel (30) into the core segments for supporting and maintaining the axial position of the core segments. Coupling is by elastic interference between the flexible mandrel and the core segments to form an assembly in which the core segments are arranged on the mandrel spaced apart or adjacent one to the other.