Foldable Hinge Structure With Wire-Pulley Rotation Synchronization

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Solution Overview

Problem

There is a trade-off between the size of the display and the miniaturization of electronic devices, particularly in foldable devices, where existing hinge structures do not effectively manage the rotation of display components without causing excessive stress or structural integrity issues.

Innovation Solution

A hinge structure with a rotation structure and interlocking mechanism using pulley shafts and a wire system to synchronize the rotation of housings, ensuring equal angular movement and reducing stress on the display, while incorporating a fixing structure to maintain desired angles and prevent unwanted movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the display size is increased to support multimedia services, then the display area is improved, but the device size and portability deteriorate

Engineering Contradiction:
Improvedisplay areaVSAvoiddevice size
Core Design Contradiction:
Area of stationary objectVSVolume of moving object

Solution Approach 1:

The display is divided into two separate housings (first housing and second housing) that can be folded relative to each other. This segmentation allows the total display area to be large while the folded device volume remains compact, resolving the contradiction between display size and portability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The display extends into the third dimension by folding along a hinge axis. When unfolded, the display provides a large area; when folded, the device maintains a compact form factor. This dimensional transformation allows large display area without proportionally increasing device volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If a hinge structure is used to enable folding, then the device portability is improved, but the structural integrity and stress management of the display deteriorate

Engineering Contradiction:
Improvedevice volumeVSAvoidstructural integrity
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

An interlocking structure acts as an intermediary between the first and second housings. This structure includes a first pulley shaft, second pulley shaft, and wire that work together to synchronize the rotation of both housings, ensuring equal angular movement and preventing excessive stress on the display during folding operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The hinge structure controls the angular parameters of both housings to maintain equal rotation angles. By monitoring and adjusting the rotation parameters, the system prevents excessive bending angles that could damage the display while enabling the folding motion needed for portability.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the housings rotate independently, then the device flexibility is improved, but the synchronization and stress distribution of the display deteriorate

Engineering Contradiction:
Improvedevice flexibilityVSAvoiddisplay stress
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The interlocking structure provides mechanical feedback between the two housings. The wire and pulley system continuously monitors and adjusts the rotation of each housing to maintain synchronization, ensuring that both sides rotate by equal angles and preventing uneven stress distribution on the display.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The interlocking structure serves as a mediator that coordinates the independent rotation of both housings. By transmitting rotational force through the wire and pulley shafts, it ensures that both housings move in unison, maintaining display integrity while allowing flexible folding motion.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 proposed hinge structure allows for synchronized rotation of display components, reducing stress and maintaining structural integrity, thus enabling a seamless folding and unfolding experience without increasing production costs or susceptibility to damage.

Implementation Method 1

a wire connected to the first pulley shaft and the second pulley shaft. The wire is configured to rotate the second pulley shaft based on rotation of the first pulley shaft

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4336808B1Foldable electronic device comprising hinge structure
Publication Date: 2025.10.08 SAMSUNG ELECTRONICS CO LTD
  • EP4336808B1 patent drawingFigure 1
  • EP4336808B1 patent drawingFigure 2
  • EP4336808B1 patent drawingFigure 3

AI summary

An electronic device is provided. The electronic device may include a housing including a first housing and a second housing, a flexible display disposed on the first housing and the second housing, and a hinge structure connecting the first housing and the second housing to each other. The hinge structure may include a rotation structure including a rotation bracket, a first rotation member accommodated in the rotation bracket and connected to the first housing, and a second rotation member accommodated in the rotation bracket and connected to the second housing, and an interlocking structure configured to transfer rotational force of the first housing to the second housing. The interlocking structure may include a first pulley shaft rotatably connected to the rotation bracket, a second pulley shaft rotatably connected to the rotation bracket, a wire connected to the first pulley shaft and the second pulley shaft and configured to rotate the second pulley shaft based on rotation of the first pulley shaft or rotate the first pulley shaft based on rotation of the second pulley shaft, and an idler pulley located between the first pulley shaft and the second pulley shaft and configured to guide movement of the wire. Various other embodiments are available.