Elliptical Pneumatic Actuator Wedge Base Stability

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Solution Overview

Problem

Conventional pneumatic bulbs used in nurse call systems are unstable on flat surfaces and require excessive effort to activate, making them unsuitable for patients with severely restricted mobility, as they often shift on patient mattresses and demand physical exertion beyond their capabilities.

Innovation Solution

A pneumatically actuated switching device featuring an elliptical dome with a wedge-shaped base and upstanding support columns, allowing for easy anchoring and minimizing the effort required to pressurize air, with a design that enables activation by brushing against it with the cheek or head, and self-sustaining ribs for stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional pneumatic bulb with hemispherical end parts and cylindrical mid-section is used, then the bulb can generate sufficient pressurized air to operate the switching circuit, but the cylindrical configuration causes the bulb to be fundamentally unstable on a flat surface and cannot remain in a fixed location

Engineering Contradiction:

Improvestability of pneumatic bulb on flat surfaceVSAvoidfixed location on patient mattress

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies asymmetry by changing the bulb shape from a symmetric cylindrical configuration to an asymmetric design with a wedge-shaped base and hemispherical end parts. The wedge-shaped base creates an asymmetric footprint that provides stable positioning on flat surfaces, preventing the bulb from rolling or shifting while maintaining its pressurized air generation capability.

Inventive Principle:

Principle #4Asymmetry

2Strength

If a pneumatic bulb with a center post and doughnut-like dome is used, then the bulb can provide structural support, but the elastic compression required exceeds the capabilities of patients with severely limited physical capabilities

Engineering Contradiction:

Improvestructural support of pneumatic bulbVSAvoideffort required to activate by patient

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The patent applies spheroidality by using a hemispherical end part instead of a doughnut-like dome with a center post. The hemispherical shape provides inherent structural strength and stability while creating a larger, more accessible actuating surface that requires minimal force to activate, making it suitable for patients with limited physical capabilities.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of operation

If a pneumatic bulb is designed for easy activation by patients with restricted mobility, then the activation force required is minimized, but the bulb becomes unstable and shifts on the patient mattress

Engineering Contradiction:

Improveactivation effort for patients with restricted mobilityVSAvoidstability of pneumatic bulb on mattress

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the bulb into distinct functional segments: a wedge-shaped base for stability, hemispherical end parts for structural integrity and actuation, and a cylindrical mid-section for air containment. This segmentation allows each part to optimize its function - the base provides stable positioning while the hemispherical ends provide easy activation surfaces.

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

The device provides a stable and easily accessible means for patients to activate a nurse call system with reduced physical effort, ensuring reliable operation and preventing the bulb from shifting, thus enhancing patient safety and usability.

Implementation Method 1

generate a volume of pressurized air sufficient to operate an electrical switching circuit

Methodology Applied

Scientific EffectPressurization: Pressure Increase

Implementation Method 2

deflection of the convex actuating wall

Methodology Applied

Scientific EffectElastic deformation: Deformation

Data Source

PatentUS7449646B1Elliptical pneumatic actuator with a wedge shaped base

Publication Date: 2008.11.11 DWYER PRECISION PRODS

AI summary

A pneumatically actuated switching device has an elliptical dome with spaced apart support columns protruding from a concave inner face surface for anchoring to a floor of a wedge shaped base. The base is elliptical and bounded by an endless upstanding sidewall having a projected edge that varies continuously in height about one of the major axis and the minor axis, the projected edge having one of a channel and a locking lip and the other of the channel and the locking lip being formed on the elliptical edge for interlocking engagement in an air tight fashion. An electrically conductive switch is coupled by a duct for responding to a volume of pressurized air within the dome and the base by deflection of the convex actuating wall.