Dynamic Foam Mattress Alignment on Variable-Length Hospital Beds

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Solution Overview

Problem

In clinical environments, advanced hospital bed frames with complex articulation can lead to improper positioning of mattress components relative to patients, resulting in decreased performance due to internal components displacement within the mattress cover.

Innovation Solution

A patient support apparatus featuring a foam frame, bladder assembly, and cover with knobs that engage an articulated frame to control movement, ensuring the bladder assembly has a range of motion relative to the foam frame, and includes foam-filled bladders with different performance characteristics for varying support across the patient's body, along with unpowered relief and check valves to regulate pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If advanced articulation is added to hospital bed frames to allow for better customized adjustment and positioning, then patient positioning capability is improved, but mattress component positioning accuracy deteriorates due to relative movement between mattress and frame

Engineering Contradiction:
Improvepatient positioning capabilityVSAvoidmattress component positioning accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The mattress is designed with dynamic characteristics that allow it to move with the articulated frame. The bladder assembly is positioned within the mattress cover to have a range of movement relative to the foam frame, enabling the mattress to adapt to frame articulation while maintaining proper component positioning relative to the patient.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Knobs are introduced as intermediary elements that engage between the mattress assembly and the articulated frame. These knobs control the movement of the bladder assembly in response to frame movement, acting as a mediator that translates frame articulation into controlled mattress component positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the bladder assembly is secured rigidly to the foam frame, then structural stability is improved, but component displacement occurs during frame articulation leading to decreased performance

Engineering Contradiction:
Improvestructural stabilityVSAvoidmattress performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The bladder assembly is engaged with the foam frame such that it has a controlled range of movement rather than being rigidly fixed. This dynamic engagement allows the bladder assembly to move in response to frame articulation while maintaining proper positioning, preventing component displacement and maintaining reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The knobs provide a feedback mechanism that responds to frame movement and automatically adjusts the bladder assembly position. When the articulated frame moves, the knobs detect this movement and control the bladder assembly to move accordingly, maintaining proper component positioning without rigid connection.

Inventive Principle:
Principle #23Feedback

3Reliability

If foam-filled bladders with different performance characteristics are used to provide varying support, then patient support performance is improved, but device complexity increases

Engineering Contradiction:
Improvepatient support performanceVSAvoidmattress structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Different regions of the mattress contain foam-filled bladders with different performance characteristics. The first group of bladders has different properties than the second group, allowing localized optimization of support for different body regions (head portion vs. torso portion) while using a relatively simple overall structure.

Inventive Principle:
Principle #3Local quality

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 solution ensures proper alignment and support of the mattress components with the bed frame, maintaining optimal pressure distribution and preventing pressure-related injuries, even with complex articulation movements, while being self-adjusting and safe for larger patients.

Implementation Method 1

the manifold having an unpowered relief valve configured to release air from the bladder assembly if the pressure in the bladder assembly exceeds a predetermined limit of the relief valve

Methodology Applied
Scientific EffectPressure relief valve mechanism: Pressure Gradient

Implementation Method 2

some of the plurality of foam-filled bladders may include an unpowered check valve configured to open and permit atmospheric air to enter the respective bladder if the pressure in the bladder assembly is lower than the pressure of atmospheric air

Methodology Applied
Scientific EffectCheck valve mechanism: Pressure Gradient

Data Source

PatentEP3892248B1Dynamic foam mattress adapted for use with a variable length hospital bed
Publication Date: 2024.11.13 HILL ROM SERVICES INC
  • EP3892248B1 patent drawingFigure 1
  • EP3892248B1 patent drawingFigure 2
  • EP3892248B1 patent drawingFigure 3

AI summary

A patient support apparatus comprising: a foam frame (72) defining a space (80); a bladder assembly (70) positioned in the space (80); and a cover (82, 84) enclosing the foam frame (72) and the bladder assembly (70). The patient support apparatus is adapted to engage an articulated frame (24). The patient support apparatus further includes at least one protrusion (174, 176, 178, 180) secured to the bladder assembly (70) and configured to engage the articulated frame (24) to control movement of the bladder assembly (70) in response to movement of the articulated frame (24). The bladder assembly (70) is engaged with the foam frame (72) such that the bladder assembly (70) has a range of movement relative to the foam frame (72) when members of the articulated frame (24) move.