Pendulum Hinge With Symmetric Spring Torque Control

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Solution Overview

Problem

Existing hinges for swing doors suffer from issues such as spring fatigue, uneven force distribution, torsional vibrations, high friction, and complex installation, particularly in designs using torsion springs or sliding surfaces, which lead to material fatigue and uneven force transmission.

Innovation Solution

A pendulum hinge design that utilizes symmetrically arranged compression springs guided linearly along the hinge's longitudinal axis, redirecting force directly to the lever's point of application, minimizing friction and allowing torque adjustment based on the opening angle, ensuring uniform torque distribution and preventing rapid closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If torsion springs are used in the hinge, then the door can swing open in both directions and be returned to the central position, but the springs can fatigue and break over time when twisted more than 90°, and the torque can be disproportionate to the opening angle

Engineering Contradiction:
Improvedoor swing capabilityVSAvoidspring service life
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the spring configuration from torsion springs to extension springs arranged symmetrically. This parameter change allows the springs to operate within elastic limits without excessive twisting, eliminating fatigue and breakage while maintaining the door's bidirectional swing capability and automatic return to center position.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using torsion springs that twist to generate force, the patent inverts the approach by using extension springs that extend and contract symmetrically on both sides of the hinge axis. This inversion distributes the force evenly and prevents the disproportionate torque and spring fatigue associated with traditional torsion spring designs.

Inventive Principle:
Principle #13The other way round (Inversion)

2Device complexity

If torsion springs are positioned at the upper corner of the door leaf, then the hinge structure is simplified, but the force distribution becomes uneven resulting in torsional vibrations

Engineering Contradiction:
Improvehinge structureVSAvoidforce distribution uniformity
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent uses symmetric arrangement of spring mounting points relative to the hinge axis, creating balanced force distribution. This symmetry ensures that forces are evenly distributed during door operation, preventing torsional vibrations while maintaining structural simplicity.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The symmetrically arranged extension springs act as counterbalancing elements on both sides of the hinge axis, providing balanced restoring forces that counteract the door's weight and prevent uneven force distribution and torsional vibrations during operation.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Strength

If three hinges are required in addition to the closer, then the hinge system provides sufficient support, but the technical complexity increases and installing and removing the door leaf becomes cumbersome

Engineering Contradiction:
Improvedoor supportVSAvoidhinge system
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines the functions of multiple hinges and the door closer into a single integrated pendulum hinge unit. The symmetric spring mechanism provides both the support function of multiple hinges and the automatic closing function of a closer, eliminating the need for separate components and simplifying installation and removal.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pendulum hinge with symmetric extension springs serves multiple functions simultaneously: it provides structural support like multiple hinges, enables bidirectional swinging, ensures automatic return to center position, and acts as a door closer. This multi-functionality reduces the overall system complexity while maintaining sufficient door support.

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

4Ease of operation

If sliding surfaces are used in the hinge parts, then the hinge allows pivoting motion, but high frictional forces arise on the surfaces

Engineering Contradiction:
Improvepivoting motionVSAvoidfrictional force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent extracts and eliminates the sliding surfaces from the hinge design, replacing them with a pivot-based mechanism. This removal of sliding contacts eliminates the high frictional forces while preserving the pivoting motion capability through the symmetric extension spring arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

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 pendulum hinge achieves nearly linear torque over a wide range, prevents torsional vibrations, and maintains high torque near closure, reducing material stress and simplifying installation by eliminating sliding friction and uneven force distribution.

Implementation Method 1

the two hinge parts are operatively connected to each other by spring tension via a spring assembly

Methodology Applied
Scientific EffectSpring tension: Spring

Implementation Method 2

the compression springs are guided linearly along their axes which are aligned parallel to the longitudinal axis by a linear guide

Methodology Applied
Scientific EffectLinear guidance:

Implementation Method 3

the spring element is formed from at least two compression springs extending symmetrically to a longitudinal axis of the adjacent hinge parts

Methodology Applied
Scientific EffectSymmetric force distribution:

Implementation Method 4

the hinge parts are pivotably connected via two axes of rotation with adjacent sliding surfaces

Methodology Applied
Scientific EffectPivoting motion: Hinge

Implementation Method 5

redirecting force directly to the lever's point of application, minimizing friction

Methodology Applied
Scientific EffectFriction reduction: Friction

Data Source

PatentEP4647571A1Pendulum hinge
Publication Date: 2025.11.12 COFANO GIUSEPPE
  • EP4647571A1 patent drawingFigure 1
  • EP4647571A1 patent drawingFigure 2~3
  • EP4647571A1 patent drawingFigure 4~5c

AI summary

The present invention relates to a pendulum hinge (1) with two hinge parts (10, 11) for pivotally connecting several components (2, 3), wherein the hinge parts (10, 11) are pivotably connected via two axes of rotation (A', A'') with adjacent sliding surfaces (1000, 1100), wherein, to form the two axes of rotation (A', A''), at least two spaced-apart receptacles (100) for forming the sliding surfaces (1000) are provided on the first hinge part (10), and at least two sliding bodies (110) corresponding to the receptacles (100) on the first hinge part (11) and designed to form the sliding surfaces (1100) on the second hinge part (11) are provided, wherein the two hinge parts (10, 11) are operatively connected to each other by spring tension via at least one spring device (12).wherein the spring assembly (12) is formed from at least one connecting part (120) which can be reversibly arranged on the second hinge part (11) and at least one spring element (121) which holds the connecting part (120), wherein the spring element (121) is formed from at least two compression springs (1210', 1210'') extending symmetrically to a longitudinal axis (L) of the adjacent hinge parts (10, 11) which runs through the connecting part (120), wherein the compression springs (1210', 1210'') are guided linearly along their axes (DA) which are aligned parallel to the longitudinal axis (L) by a linear guide (122). The pendulum hinge (1) according to the invention is characterized in that the compression springs (1210', 1210'') are designed to exert a tensile force on the connecting part (120) by means of their corresponding mounting on shaped parts (1220', 1220''; 1220''', 1220ʺʺ) of the linear guides (122) arranged in pairs symmetrically to the longitudinal axis (L).