Linear Actuator With Vacuum Rod Recall for Consistent Force

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Solution Overview

Problem

Existing linear actuators, such as hydraulic, pneumatic, and gas spring actuators, face issues with fluid management, maintenance, increased force requirements over time, and unsuitability for non-industrial applications like sliding doors due to their design and operational constraints.

Innovation Solution

A linear actuator with a jacket and rod system, featuring independently fluidic compartments that maintain vacuum and atmospheric pressure, allowing for consistent force requirements and minimal maintenance, using control means to manage air flow for controlled movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If hydraulic or pneumatic actuators are used, then linear movement can be achieved, but fluid management complexity and maintenance requirements increase

Engineering Contradiction:
Improvelinear movement capabilityVSAvoidfluid management complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the working fluid from the system by using vacuum to remove air and gases from the cylinder chamber during operation. This eliminates the need for external fluid supply lines and management systems while maintaining the linear actuation function, directly resolving the contradiction between achieving linear movement and avoiding fluid management complexity

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses vacuum pressure differential (a form of pneumatic principle) to create the force needed for linear movement. By creating a vacuum in the cylinder chamber and utilizing the pressure differential between the vacuum side and atmospheric pressure side, the system achieves linear actuation without requiring traditional hydraulic or pneumatic fluid management systems

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Ease of operation

If gas springs are used, then the rod can be recalled to rest position, but the force required to move the rod increases over time due to gas pressure increase

Engineering Contradiction:
Improverod recall capabilityVSAvoidforce required to move rod
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent changes the pressure parameter dynamically during operation. Instead of using compressed gas that increases in pressure over time, the system uses vacuum which maintains a constant pressure differential. The vacuum pump continuously maintains the vacuum level, ensuring the force required to move the rod remains constant regardless of position or time, resolving the contradiction between rod recall capability and force requirement

Inventive Principle:
Principle #35Parameter changes

3Force

If vacuum-sealed compartments are used, then consistent force can be maintained, but the system complexity increases

Engineering Contradiction:
Improveforce consistencyVSAvoidsystem complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent merges the vacuum sealing function with the existing cylinder chamber structure. The vacuum seal is integrated into the cylinder head and rod assembly rather than being a separate component, and the vacuum pump serves dual purposes of both creating vacuum for force generation and maintaining the seal. This integration maintains force consistency while minimizing the increase in system complexity

Inventive Principle:
Principle #5Merging (Combining)

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

Ensures consistent force for opening/closing, minimal maintenance, and compact design suitable for various applications, including sliding doors, with automatic operation and adjustable force/speed control.

Implementation Method 1

one of the at least one first and second variable volume compartments being able to be insulated and vacuum-sealed

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

Upon the passage of the end cylinder from the rest position to the working position, one of the at least one first and second variable volume compartments may expand, so as to suck the end cylinder from the working position to the rest position by automatically recalling the at least one rod

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 3

control means for controlling the air flow flowing in/out from said other of said at least one first and second variable volume compartments to control the force necessary for the passage of said end cylinder from said rest position to said working position and/or the suction speed thereof from said working position to said rest position

Methodology Applied
Scientific EffectAir flow control:

Data Source

PatentEP3436653B1Linear actuator, as well as closing / opening system that includes such actuator
Publication Date: 2025.09.03 IN & TEC
  • EP3436653B1 patent drawingFigure 1a~2a
  • EP3436653B1 patent drawingFigure 1b~3
  • EP3436653B1 patent drawingFigure 4a~5

AI summary

A linear actuator comprising at least one jacket (10) defining an axis (X) and at least one rod (20) having an end cylinder (21) tightly slidable in the at least one jacket (10) and an opposite end (22) sliding between a rest position and a working position. The end cylinder (21) divides the at least one jacket (10) into at least one first and second variable volume compartments (18', 18") fluidically independent to each other, one of them (18', 18") being fluidically insulated and under vacuum, the other (18', 18") being fluidically communicating with the outside environment. Upon the passage of the opposite end (22) from the rest position to the working position one of the compartments (18', 18") passes from a minimum volume to a maximum volume, in order to suck the at least one rod (20) automatically recalling the opposite end (22) from the working position to the rest position.