Resistive Pressure Sensor for Mattress Support

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current pressure sensors for regulating inflatable cell support devices, such as therapeutic mattresses, are costly, thick, and complex, limiting their use to hospitals and making them impractical for home medicalization due to high manufacturing costs and maintenance challenges, and they require sophisticated interfaces and electronic systems that are difficult to maintain or replace.

Innovation Solution

A pressure sensor using resistive force detection cells housed in a compressible intermediate layer between protective plates, which provides a sensitive and proportional analog signal for loads from 40 to 210 kg, allowing for efficient regulation of inflatable cell pressure and easy integration under the mattress to avoid direct contact with the patient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If inductive sensors are used to measure sinking distance, then measurement capability is provided, but manufacturing cost increases and device thickness increases

Engineering Contradiction:
Improvesinking distance measurementVSAvoidsensor thickness
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electromagnetic inductive sensors with a simple resistive force detection cell that converts mechanical pressure directly into electrical resistance changes. This mechanical-to-electrical conversion eliminates the need for complex electromagnetic fields and moving parts, achieving measurement functionality with a thin, simple structure.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The resistive force detection cell uses inexpensive materials such as conductive ink or semiconductor material deposited on a flexible substrate. This approach replaces expensive inductive sensors with a cost-effective, simple resistive element that can be easily manufactured and replaced if needed.

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

2Measurement precision

If hydraulic sensors with inflatable chambers are used, then pressure sensing is provided, but manufacturing cost increases and device thickness increases

Engineering Contradiction:
Improvepressure sensingVSAvoidsensor thickness
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces hydraulic pressure sensing mechanisms with a direct resistive measurement approach. Instead of using inflatable chambers filled with low-compressible fluid to transmit pressure, the resistive force detection cell directly measures pressure through changes in electrical resistance, eliminating the need for fluid-filled chambers and associated complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention extracts only the essential pressure-sensing function from complex hydraulic systems. By using a thin resistive cell that directly detects pressure through resistance changes, it removes the unnecessary inflatable chamber structure and fluid transmission components, achieving pressure sensing with minimal thickness.

Inventive Principle:
Principle #2Taking out (Extraction)

3Extent of automation

If sophisticated electronic control and regulation devices are used, then pressure regulation capability is provided, but device complexity and maintenance difficulty increase

Engineering Contradiction:
Improvepressure regulationVSAvoidelectronic system complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the resistive force detection cell continuously monitors pressure and sends signals to a control device that adjusts inflatable cell pressure accordingly. This closed-loop feedback mechanism automates pressure regulation while keeping the sensing component simple, reducing overall system complexity compared to sophisticated sensors.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The resistive force detection cell provides self-service by automatically converting pressure into electrical signals without requiring complex signal processing or calibration. Its simple resistive output can be directly read by control electronics, eliminating the need for sophisticated interfaces and reducing maintenance requirements.

Inventive Principle:
Principle #25Self-service

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 sensor offers a cost-effective, thin, and robust solution for pressure regulation, providing precise and reliable measurements while being easy to maintain and replace, enabling wider use in home medical settings and reducing the thickness of support devices, thus improving patient safety and reducing healthcare costs.

Implementation Method 1

at least one resistive force detection cell (2) sensitive to the pressures applied by the body of a patient

Methodology Applied
Scientific EffectPiezoresistive Effect: Piezoresistive Effect

Data Source

PatentEP2031362B1Sensor for detecting and measuring pressure including at least one force-detecting resistive cell
Publication Date: 2011.11.16 HILL ROM INDS
  • EP2031362B1 patent drawingFigure 1A~1B
  • EP2031362B1 patent drawingFigure 2~3
  • EP2031362B1 patent drawingFigure 4

AI summary

The sensor (1) has a resistive cell (2) i.e. force imaging technology cell, detecting forces applied on a rigid base-plate (7), where the cell and the base-plate is housed in a suspension (8) formed in a compressible intermediate layer (5). The layer is disposed between two rigid or semi-rigid protection plates (3, 4), where the layer is made of a woven polyester based material. The plates (3, 4) are made of plastic material such as PVC, polypropylene, polyethylene or acrylonitrile butadiene styrene. The base-plate is constituted of an epoxy resin plate and aluminum based material plate. An independent claim is also included for a method for detecting load pressure applied on a support device.