Collapsible Structure Curvature Control Under Negative Pressure

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Solution Overview

Problem

Current technologies lack a structure that can adjust its curvature under negative pressure to effectively clamp or grip objects, limiting their versatility in applications such as medical devices and industrial settings.

Innovation Solution

A collapsible clamping structure composed of elongate strips and intervening members, which can change its curvature when subjected to negative pressure, allowing it to collapse and adjust its shape to grip objects, and can be used as a steerable device or clamping tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a normal sponge is used under negative pressure, then it shrinks in all dimensions, but it cannot change shape into a more desirable shape

Engineering Contradiction:
Improveshape change capabilityVSAvoidshape control under negative pressure
Core Design Contradiction:
ShapeVSAdaptability or versatility

Solution Approach 1:

The sponge is divided into multiple cells with different geometries (e.g., tetrahedral, octahedral, icosahedral cells) arranged in specific patterns. Each cell type collapses differently under negative pressure, enabling the structure to transform from an expanded state to various collapsed shapes while maintaining control over the final configuration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The structure combines multiple cell types with different collapse characteristics into a composite cellular architecture. This composite cellular structure allows different regions to collapse in different ways, enabling complex shape changes and curvature adjustments that a uniform material cannot achieve.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If a collapsible structure is designed to change shape under negative pressure, then it can grip objects, but the structure complexity increases

Engineering Contradiction:
Improvegripping capabilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cellular structure is designed to automatically transform and grip objects when negative pressure is applied, without requiring external actuators or complex control mechanisms. The geometric arrangement of cells inherently provides the gripping action through passive collapse, reducing mechanical complexity while maintaining functional adaptability.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The structure exploits changes in physical parameters (volume, shape, curvature) of the cellular framework under negative pressure to achieve gripping. By designing cells with specific geometric parameters, the structure transforms these parameter changes into useful gripping forces and shapes without adding mechanical complexity.

Inventive Principle:
Principle #35Parameter changes

3Force

If the clamping structure collapses to grip objects, then the clamping force increases, but the distance between ends decreases

Engineering Contradiction:
Improveclamping forceVSAvoiddistance between ends
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The cellular structure collapses primarily in the lateral dimensions (width and height) rather than the longitudinal dimension, allowing the structure to increase clamping force through lateral compression while maintaining a sufficient length between ends for functional operation. This dimensional selectivity enables simultaneous achievement of high clamping force and adequate span.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The cellular arrangement and collapse mechanism are designed to create curvature in the structure during collapse. This curvature allows the ends to approach each other for gripping while the overall arc length maintains adequate distance, enabling the structure to achieve high clamping force without completely reducing the end-to-end distance.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 structure effectively changes its curvature under negative pressure, enabling it to securely grip objects and adapt to various shapes, enhancing its utility in medical and industrial applications by providing a reversible and adjustable clamping mechanism.

Implementation Method 1

negative pressure, or partial vacuum, is widely used in many areas... a porous sponge may collapse under negative pressure

Methodology Applied
Scientific EffectNegative pressure: Vacuum

Implementation Method 2

negative pressure provides chemical inertness, promotes evaporation and sublimation, and produces suction powers

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP3638169B1Collapsible structure and method of use
Publication Date: 2024.11.13 SMITH & NEPHEW PLC
  • EP3638169B1 patent drawingFigure 1
  • EP3638169B1 patent drawingFigure 2A
  • EP3638169B1 patent drawingFigure 2B

AI summary

A collapsible, clamping and/or steerable apparatus in conjunction with negative pressure system and methods for using such an apparatus are described. Preferred embodiments of the invention have lengths and bent and/or increase their curvatures along their lengths, by preferentially contracting and transforming upon negative pressure.