Weighing Scale Zeroing Bed Automatic Load Compensation

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Solution Overview

Problem

Caregivers face challenges in accurately determining a patient's weight due to non-patient loads on patient support apparatuses, leading to incorrect medical diagnoses and treatment, and require cumbersome reset procedures for new patients.

Innovation Solution

A patient support apparatus with a controller that uses load cells to detect and differentiate between patient and non-patient loads, automatically updating net weights and resetting occupancy timers based on load changes, ensuring accurate weight calculations and streamlined patient transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If caregivers manually remove non-patient loads before weighing, then weight measurement accuracy is improved, but caregiver workload and time consumption increase

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidcaregiver workload
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The weighing scale performs automatic zeroing and non-patient load detection without requiring caregiver intervention. The system autonomously identifies when non-patient loads are present and compensates for their weight, eliminating the need for manual removal while maintaining measurement accuracy.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical process of removing non-patient loads with an automated electronic detection and compensation system. Load cells and control algorithms automatically detect weight changes and calculate true patient weight, substituting physical manipulation with electronic intelligence.

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

2Measurement precision

If the weighing scale is manually reset for each new patient, then measurement accuracy is improved, but time consumption and operational complexity increase

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidreset time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system automatically performs the zeroing operation when it detects that a patient has been placed on the support apparatus. This preliminary automatic action ensures the scale is properly calibrated before weight measurement begins, eliminating the need for manual reset procedures.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The weighing scale autonomously manages its own calibration state by detecting patient presence and automatically zeroing when appropriate. The system monitors its own operational state and performs necessary reset functions without external intervention, improving workflow efficiency.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If non-patient loads are not removed before weighing, then caregiver convenience is improved, but measurement accuracy deteriorates

Engineering Contradiction:
Improvecaregiver convenienceVSAvoidweight measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical requirement of physically removing non-patient loads with an electronic detection and compensation system. Load cells detect weight changes, and the control system automatically calculates and subtracts non-patient load weights from the total measurement, maintaining accuracy while improving convenience.

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

Solution Approach 2:

The control system acts as an intermediary between the raw weight measurement and the final displayed result. It processes the total weight signal, identifies non-patient load components through detection algorithms, and computes the true patient weight, mediating between the presence of non-patient loads and accurate measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Measurement precision

If the system automatically detects non-patient loads, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveweight measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control system performs multiple functions using the same hardware components: it monitors weight measurements, detects patient presence, identifies non-patient loads, and calculates true weights. This multi-functionality reduces the need for additional specialized components, managing complexity while enhancing capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system continuously monitors weight signals from load cells and uses feedback loops to detect changes indicative of non-patient load addition or removal. The control algorithm adjusts calculations based on real-time feedback from the sensing elements, enabling automatic detection without requiring separate dedicated sensors.

Inventive Principle:
Principle #23Feedback

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

This solution provides accurate patient weight measurements by accounting for non-patient loads and automating the reset process, reducing errors in medical assessments and simplifying caregiver tasks.

Implementation Method 1

a plurality of load cells that supports the patient support. Each load cell is configured to produce a signal indicative of a load on that load cell

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3091341B1Weighing scale zeroing bed
Publication Date: 2021.02.17 HILL ROM SERVICES INC
  • EP3091341B1 patent drawingFigure 1
  • EP3091341B1 patent drawingFigure 2
  • EP3091341B1 patent drawingFigure 3

AI summary

A patient support apparatus includes a controller operable to determine the true patient weight by detecting the net weight change of the patient supported on the patient support apparatus. The controller is configured to automatically detect and distinguish the addition or removal of non-patient loads from patient-related loads by determining the rate of weight change of each weight event signals. The controller is further configured to determine the net weight change of the patient by automatically updating a net weight of the non-patient loads on the patient support apparatus.