Electromagnetic Door Closer Hinge Without Oil Leakage

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Solution Overview

Problem

Conventional door closers often rely on oil, which poses fire safety risks, are bulky, unreliable due to temperature changes and wear, and have unsatisfactory reliability, and lack a compact and cost-effective design.

Innovation Solution

A compact door closer arrangement that integrates a mechanical force device to store and release mechanical energy, an electromagnetic generator to generate electric energy, and a control system for precise movement control, all housed within a slim tubular design, optionally including a friction brake and freewheel for enhanced functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional door closers use oil-based hydraulic cylinders, then damping force can be provided, but fire safety is compromised and leakage occurs

Engineering Contradiction:
Improvefire safetyVSAvoidoil leakage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the oil-based hydraulic damping system with an electromagnetic damping system. The electromagnetic generator creates damping force through electromagnetic interaction between the stator and rotor, eliminating the need for oil while maintaining the damping function and improving fire safety.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the working medium from oil to electromagnetic fields. By converting the hydraulic damping mechanism into an electromagnetic one, the system achieves the same damping effect without the harmful properties of oil, such as fire risk and leakage.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional door closers use spring and hydraulic cylinder, then closing function is achieved, but the device becomes bulky

Engineering Contradiction:
Improveclosing functionVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the hinge function and door closer function into a single integrated unit. The electromagnetic generator is positioned concentrically with the hinge axis, combining the rotational support and closing functions in one compact assembly, eliminating the need for separate hydraulic cylinders and springs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electromagnetic generator serves multiple functions: it provides the closing force, generates electromagnetic energy during operation, and acts as the hinge mechanism. This multi-functionality reduces the overall device size by eliminating redundant components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Speed

If conventional door closers use oil-based systems, then damping is provided, but reliability decreases due to temperature changes and wear

Engineering Contradiction:
Improvedamping forceVSAvoidtemperature stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent replaces the oil-based hydraulic system with an electromagnetic system that is inherently insensitive to temperature changes. The electromagnetic damping force is generated through magnetic field interaction, which does not suffer from the temperature-dependent viscosity changes that affect oil-based systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical principle from hydraulic fluid damping to electromagnetic damping. This fundamental parameter change eliminates the reliability issues associated with oil performance degradation under temperature variations and wear.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If conventional door closers use multiple components, then function is achieved, but installation complexity increases

Engineering Contradiction:
Improveclosing functionalityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple functions (hinge, closer, energy generator) into a single integrated unit with concentric arrangement. This reduces the number of separate components and simplifies installation while maintaining all necessary functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electromagnetic generator performs multiple functions simultaneously: providing closing force, generating electromagnetic energy, and serving as the hinge mechanism. This multi-functionality reduces component count and simplifies the overall system.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Provides a reliable, compact, and cost-effective door closer with improved latching and smart control features, eliminating the need for oil and reducing installation complexity.

Implementation Method 1

an electromagnetic generator arranged to be driven by the closing movement to generate electric energy

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a mechanical force device configured to store mechanical energy from an opening movement of the access member part from the closed position to the open position, and configured to release the stored mechanical energy to a closing movement

Methodology Applied
Scientific EffectSpring energy storage: Spring

Data Source

PatentEP4367354B1Arrangements for closing access member, and access member systems
Publication Date: 2026.04.15 ASSA ABLOY AB
  • EP4367354B1 patent drawingFigure 1
  • EP4367354B1 patent drawingFigure 2
  • EP4367354B1 patent drawingFigure 3

AI summary

An arrangement 20a-20c) for closing an access member (14) rotatable relative to a frame (12), the arrangement comprising a frame part (30) for fixation to the frame; an access member part (32) for fixation to the access member, the access member part being rotatable relative to the frame part about a hinge axis (16) between a closed position (18) and an open position (24); a mechanical force device (40, 92) configured to store mechanical energy from an opening movement (26) of the access member part from the closed position to the open position, and configured to release the stored mechanical energy to a closing movement (28) of the access member part from the open position to the closed position; an electromagnetic generator (48) arranged to be driven by the closing movement to generate electric energy; and a freewheel (58) arranged to disengage during the opening movement and to engage during the closing movement to drive the generator.