Concealed Door Closer Using Flexible Elements and Adjustable Damping

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Solution Overview

Problem

Existing door closing systems are visible, cause excessive stress on components, require structural complexity, and have limited adjustability and opening range, often necessitating costly and invasive installation.

Innovation Solution

A concealed door closing device using elastic flexible elements and a damping system, where the flexible elements are housed within fixing elements, allowing adjustable braking and hidden operation, with a damping mechanism to manage door movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional door closing systems are used, then door closing function is achieved, but the device is visible from outside during operation

Engineering Contradiction:
Improveconcealment of deviceVSAvoidstructural complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The elastic flexible elements are nested within the fixing elements, with the first elastic element housed in the first fixing element and the second elastic element housed in the second fixing element. This nesting arrangement conceals the closing device during door operation while maintaining its functional integrity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The closing device is segmented into multiple independent components: first fixing element, second fixing element, first elastic flexible element, and second elastic flexible element. Each component performs a specific function and can be independently positioned, allowing the device to remain concealed while operational.

Inventive Principle:
Principle #1Segmentation

2Strength

If conventional hinge systems are used, then door rotation is enabled, but excessive stress is exerted on hinge components

Engineering Contradiction:
Improvestress on hingesVSAvoiddoor operation smoothness
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The elastic flexible elements change their mechanical parameters (flexibility, stress distribution) based on the door position. When the door is closed, the elements are contained within the fixing elements providing structural support. When the door opens, the elements flex and distribute stress, reducing peak loads on hinge components.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic flexible elements act as cushioning elements that absorb and distribute mechanical stress before it reaches the hinge components. The elements are pre-positioned within the fixing elements to provide stress distribution during door operation, protecting the hinges from excessive localized loads.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If door closing devices are installed, then door closing capability is provided, but drilling holes in floor or walls is required

Engineering Contradiction:
Improveinstallation flexibilityVSAvoidinstallation invasiveness
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The fixing elements are designed with universal mounting capabilities that can accommodate different door types and installation scenarios. The elements can be fixed to various surfaces (door edge, jamb, wall) using different attachment methods, providing installation flexibility without requiring invasive floor or wall drilling in all cases.

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

4Force

If rigid closing mechanisms are used, then door closing force is sufficient, but the range of door opening is limited

Engineering Contradiction:
Improvedoor closing forceVSAvoiddoor opening range
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The closing mechanism uses elastic flexible elements instead of rigid components. These flexible elements can bend and extend through a larger angular range while maintaining closing force. The flexibility of the elements allows the door to open to greater angles without compromising the closing capability, as the elements can accommodate larger deformations.

Inventive Principle:
Principle #30Flexible shells and thin films

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 hidden, stress-reduced, and structurally simple solution with adjustable braking, enhancing door operation while maintaining mechanical integrity and versatility across different hinge configurations.

Implementation Method 1

a first elastic flexible element (11) which, due to its configuration, performs an elastic function when subjected to bending

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a damping system for damping the return movement of said first fixing element towards said second fixing element

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4077845B1Improved door closing device
Publication Date: 2025.11.19 KOBLENZ SPA
  • EP4077845B1 patent drawingFigure 1~3
  • EP4077845B1 patent drawingFigure 4~6
  • EP4077845B1 patent drawingFigure 7~8

AI summary

The present invention relates to a device (4) for closing a door (1 ) which is rotatably constrained to a relative anchoring structure (2) and movable between a closing position and a maximum opening position, said anchoring structure (2) being either a fixed structure or a further door. Said device (4) comprises: a first fixing element (5) fixable, in use, to the door (1 ) or to the anchoring structure (2) of the door (1 ); a second fixing element (6) fixable, in use, to the anchoring structure (2) of the door (1 ) or to the door (1 ); at least one elastic flexible element (11 ) which performs, due to its configuration, an elastic function when it is subjected to bending; fixing means (12) by which said at least one elastic flexible element (11 ) is fixed to said second fixing element (6); and engaging means (14) by which said at least one elastic flexible element (11 ) remains engaged to said first fixing element (5) during the relative motion between said first (5) and said second fixing element (6), which is caused by said door (1 ) moving between said closing position and said maximum opening position and between said maximum opening position and said closing position. In the configuration assumed by the device (4) when the door (1 ) is at least partially open, said at least one elastic flexible element (11 ) is subjected to bending and tending to automatically move said door (1 ) to said closing position.