Auto-Contour Patient Support Linkage for Stable Repositioning

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Solution Overview

Problem

Existing patient support apparatuses, such as stretchers and hospital beds, face difficulties in maintaining patient positioning, particularly when heavier patients are being cared for, as the thigh section often needs to be raised in conjunction with the head section, leading to challenges in repositioning patients who tend to migrate towards the foot end when the head is elevated.

Innovation Solution

A patient support apparatus with a linkage system that allows the thigh section to remain parallel to the seat section as the head section is raised, featuring a cam mechanism and a spring clutch that can be locked or unlocked to control the movement of the thigh section relative to the head section, enabling independent adjustment of the thigh section's position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thigh section is raised when the head section is raised, then patient migration toward the foot end is prevented, but the complexity of the mechanism increases and independent adjustment of the thigh section becomes difficult

Engineering Contradiction:
Improvepatient positioning stabilityVSAvoidmechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The linkage mechanism is designed to be selectively engageable and disengageable, allowing it to dynamically switch between coupled and independent operation modes. The clutch mechanism enables the system to transition between automatic thigh section raising (when engaged) and manual independent adjustment (when disengaged), resolving the contradiction between maintaining patient positioning stability and reducing mechanism complexity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the linkage mechanism is engaged to raise the thigh section with the head section, then patient positioning is maintained, but the ease of independent thigh section adjustment is reduced

Engineering Contradiction:
Improvepatient positioning stabilityVSAvoidindependent adjustment ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The clutch mechanism allows operators to dynamically switch between two operational states: engaged mode where the linkage automatically raises the thigh section with the head section to maintain patient positioning, and disengaged mode where the thigh section can be independently adjusted without affecting the head section. This dynamic switching capability resolves the contradiction between maintaining positioning stability and enabling easy independent adjustment.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If gas springs are used to aid head section lifting, then the effort required is reduced, but the ability to independently control thigh section movement is lost

Engineering Contradiction:
Improvehead section lifting easeVSAvoidthigh section control flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patient support apparatus is segmented into independently controllable sections through the clutch mechanism. The gas springs continue to provide assistance for head section lifting, while the selectively engageable linkage with clutch mechanism segments the control system, allowing the thigh section to be independently adjusted when the clutch is disengaged. This segmentation resolves the contradiction between ease of head section lifting and thigh section control flexibility.

Inventive Principle:
Principle #1Segmentation

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 allows for easier and safer repositioning of patients by allowing the thigh section to be raised or lowered independently of the head section, preventing patient migration and reducing the effort required for caregivers to reposition heavier patients.

Implementation Method 1

A patient support apparatus with a linkage system that allows the thigh section to remain parallel to the seat section as the head section is raised, featuring a cam mechanism and a spring clutch

Methodology Applied
Scientific EffectCam mechanism: Cam

Implementation Method 2

featuring a cam mechanism and a spring clutch that can be locked or unlocked to control the movement of the thigh section relative to the head section

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP2295016B1Patient support apparatus having auto contour
Publication Date: 2013.06.05 HILL ROM SERVICES INC
  • EP2295016B1 patent drawingFigure 1
  • EP2295016B1 patent drawingFigure 2~3
  • EP2295016B1 patent drawingFigure 4

AI summary

A patient support apparatus (20) comprises a frame (26), at least one drop rail (66) coupled to the frame and tiltable relative to the frame (26), a seat section (44) supported by the at least one drop rail (66) to tilt therewith, a thigh section (46) coupled to the seat section (44), a head section (42) coupled to the frame (26) and coupled to the at least one drop rail (66), and a linkage (400) coupled to the head section (42) and coupled to the thigh section (46). Raising and lowering of the head section (42) results in tilting of the at least one drop rail (66) relative to the frame (26). The linkage (400) has a first mode of operation in which the seat (44) and thigh sections (46) remain substantially parallel as the at least one drop rail (66) tilts. The linkage (400) has a second mode of operation in which the thigh section (46) tilts relative to the seat section (44) as the at least one drop rail (66) tilts.