Locking Sheet Structure for Thin Shape-Formable Rigidity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing shape-formable devices face limitations in conformability and rigidity due to their bulk nature and inability to extend within their plane, restricting their ability to assume complex shapes and apply forces effectively.

Innovation Solution

The development of shape-formable apparatuses with an envelope containing patterned locking sheets that can move relative to each other, allowing for extension and conformability, and transitioning from a flexible to a rigid state by evacuating the chamber, thereby increasing stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If discrete particles (bulk media) are used in a gas impermeable envelope to achieve shape-formability, then the device can be formed into a desired shape, but the volume required becomes significant and the device cannot be made thin or sheet-like

Engineering Contradiction:
Improveshape-formabilityVSAvoiddevice volume
Core Design Contradiction:
ShapeVSVolume of moving object

Solution Approach 1:

The patent replaces bulk media with thin locking sheets that have high Young's Modulus but low bending stiffness in the unjammed state. These thin sheets can be stacked in a compact configuration while maintaining the ability to form complex shapes, thereby achieving shape-formability without requiring significant volume.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical state of the locking sheets by controlling the jamming transition through pressure changes. In the unjammed state, the sheets are flexible and conformable; when jammed by reducing internal pressure, the sheets become rigid and maintain the desired shape. This parameter change allows the same structure to provide both formability and rigidity without requiring large volume.

Inventive Principle:
Principle #35Parameter changes

2Length of moving object

If multiple thin layers of material are placed in an envelope with air removed to achieve low bending stiffness, then the article can be thin with variable bending stiffness, but the layers cannot be easily extended within the plane and conformability is limited

Engineering Contradiction:
Improvethin form factorVSAvoidconformability
Core Design Contradiction:
Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The locking sheets are segmented into solid regions and open regions. The solid regions can move relative to one another within the major surface of the sheet, allowing the structure to extend in-plane and conform to complex shapes without requiring wrinkles or folds. This segmentation enables both thin form factor and high conformability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamic behavior through the jamming transition. In the unjammed state, the solid regions can move freely relative to each other, enabling extension and conformability. When jammed, the structure becomes rigid to maintain the achieved shape. This dynamic transition allows the same structure to provide both adaptability during formation and rigidity during use.

Inventive Principle:
Principle #15Dynamics

3Strength

If individual layers with high Young's Modulus are used in an unjammed state, then the material has high stiffness, but the layers cannot be easily extended within the plane and can only take on complex shapes by generating wrinkles

Engineering Contradiction:
ImproveYoung's ModulusVSAvoidextensibility
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

By segmenting the locking sheets into solid regions separated by open regions, the patent enables extension within the plane while maintaining high Young's Modulus in the solid regions themselves. The solid regions can move relative to each other through the open regions, providing extensibility without requiring the material itself to be stretched beyond its elastic limits or to form wrinkles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The open regions act as intermediaries that allow the solid regions to move relative to one another. These open regions provide the space and mechanism for extension and conformability while the solid regions maintain their high stiffness properties. This intermediary structure resolves the contradiction between high Young's Modulus and ease of extension.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If the bending stiffness of a multi-layer system is increased under vacuum by jamming the layers together, then the structure becomes more rigid, but the conformability and ability to assume complex shapes is reduced

Engineering Contradiction:
Improvebending stiffnessVSAvoidconformability
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent uses the jamming transition as a dynamic switch between two states: unjammed (flexible and conformable) and jammed (rigid and shape-stable). By controlling the pressure inside the envelope, the system can transition between these states as needed. This dynamic behavior allows the structure to be conformable during shape formation and then become rigid to maintain the desired shape, resolving the contradiction between bending stiffness and conformability.

Inventive Principle:
Principle #15Dynamics

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 achieves enhanced conformability and rigidity, allowing it to take on complex shapes and maintain desired forms with reduced volume, overcoming the limitations of bulk media devices.

Implementation Method 1

The locking sheets can jam together to resist relative motion when the pressure in the chamber is reduced below ambient pressure

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

when the pressure in the chamber is reduced below ambient pressure

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3232995B1Shape-formable apparatus comprising locking sheets
Publication Date: 2022.08.17 3M INNOVATIVE PROPERTIES CO
  • EP3232995B1 patent drawingFigure 1
  • EP3232995B1 patent drawingFigure 2A~2B
  • EP3232995B1 patent drawingFigure 3A~3B

AI summary

A shape-formable apparatus comprising locking sheets. The apparatus can have a first state in which the apparatus is formable, and a second state in which the apparatus has the desired shape and is substantially less formable than in the first state. The apparatus can further include an envelope defining a chamber, a port positioned to fluidly couple the chamber with ambience, and at least two locking sheets positioned in the chamber in an at least partially overlapping configuration. Each locking sheet comprises a major surface, and at least a portion of each locking sheet can be patterned to include solid regions and open regions, the solid regions being movable with respect to one another within the major surface.