Pneumatic Actuator with Rolling Membrane for Compact Design

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Solution Overview

Problem

Existing pneumatic actuating devices have a large actuating force and handle stroke, and are bulky, making them less suitable for compact designs and efficient operation.

Innovation Solution

A pneumatic actuating device with a rolling membrane and a conical spring design, allowing for a flatter and more compact structure with reduced friction and a shorter handle stroke, and incorporating a vent valve mechanism for precise guidance and quick closure, ensuring functional reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional pusher piston is used, then the device can generate air pulses, but the actuating force and handle stroke are comparatively large

Engineering Contradiction:
Improveactuating forceVSAvoidhandle stroke
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The patent employs a rolling membrane (flexible thin film) instead of conventional rigid sealing elements. This membrane can deform and roll during the piston's movement, allowing the piston to change its effective area dynamically. The flexible nature of the membrane enables the system to achieve the required air pulse generation with significantly reduced actuating force and shorter handle stroke, as the membrane's deformation compensates for pressure differences without requiring large mechanical inputs.

Inventive Principle:
Principle #30Flexible shells and thin films

2Force

If the pusher piston is made larger to reduce actuating force, then the device becomes bulkier, but compact design is desired

Engineering Contradiction:
Improveactuating forceVSAvoiddevice volume
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent implements a dynamic effective area for the pusher piston through the rolling membrane mechanism. Instead of using a statically large piston that would increase device volume, the membrane allows the piston's effective area to change during operation. The membrane rolls and deforms to increase the effective area only when needed for force multiplication, while maintaining a compact overall device structure. This dynamic adaptation resolves the contradiction between requiring large effective area for low actuating force and maintaining compact dimensions.

Inventive Principle:
Principle #15Dynamics

3Speed

If the pusher piston is displaced quickly, then the air pulse is generated faster, but the vent valve must close quickly to maintain vacuum

Engineering Contradiction:
Improvepiston displacement speedVSAvoidvacuum maintenance
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent incorporates a spring-loaded vent valve mechanism that is pre-loaded to ensure rapid closure. The spring is compressed in advance during the piston's outward stroke, storing potential energy that is immediately released to close the vent valve when the piston begins its return movement. This preliminary action of pre-compressing the spring ensures that the vent valve closes quickly and reliably, maintaining the vacuum seal even when the piston moves at high speed, thus resolving the contradiction between fast piston displacement and reliable vacuum maintenance.

Inventive Principle:
Principle #10Preliminary action

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 enables a compact design with reduced actuating force and handle stroke, maintaining functional reliability by minimizing friction and ensuring quick vent valve closure, suitable for actuating flushing valves with negative pressure generation.

Implementation Method 1

due to the sealing by means of the rolling membrane, even a comparatively large inclined position of the pusher piston cannot lead to jamming

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

Functional reliability is increased by an additional spring, which ensures that the vent valve is quickly closed again after the device has been actuated

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

the spring has a conical design, so that it can be compressed essentially in one plane

Methodology Applied
Scientific EffectSpring compression: Spring

Data Source

PatentEP2169126B1Pneumatic activation device
Publication Date: 2012.04.25 GEBERIT INT AG
  • EP2169126B1 patent drawingFigure 1
  • EP2169126B1 patent drawingFigure 2~3
  • EP2169126B1 patent drawingFigure 4~5

AI summary

The device has a housing (10) connected to a pneumatic line and supported in a pusher piston (24). The piston forms an inner space with the housing. The piston is moved from a position to another position using a push button (8) with respect to force of a spring (16). The inner space is reduced and the air is displaced from the inner space. The piston is relocated from the latter position to the former position by the spring. The piston is sealed and supported at periphery with a diaphragm (26) with respect to the housing.