Foldable Hinge Cam Structure for Easier Opening and Display Protection

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Solution Overview

Problem

Foldable electronic devices require excessive force to open from a closed state, and this can lead to damage to the display due to the elastic force applied by the elastic member in the cam structure.

Innovation Solution

A hinge structure with a flexible display, first and second housings, and a hinge structure that includes rotary members, arm parts with rotary cams, fixed cams, and a stopper, along with an additional structure to reduce pressure on the display during opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If an elastic member is used in the cam structure to maintain the closed state, then the closed state is maintained securely, but excessive force is needed to open the device

Engineering Contradiction:
Improveclosed state maintenanceVSAvoidforce to open device
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The cam structure is divided into multiple segments including a first cam, a second cam, and a third cam, each engaging with corresponding components. This segmentation allows the elastic force to be distributed across multiple contact points rather than concentrated at a single point, reducing the peak force required to overcome the elastic member and open the device.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A third cam is introduced as an intermediary element between the elastic member and the direct opening mechanism. The third cam engages with the second cam and helps mediate the force transmission, providing a mechanical advantage that reduces the user-applied force needed to overcome the elastic force and transition from closed to open state.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If excessive force is applied to open the device, then the closed state can be released, but damage to the display may occur

Engineering Contradiction:
Improvedevice openingVSAvoiddisplay damage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The cam structure is designed with controlled engagement surfaces and progressive disengagement paths that cushion the transition from closed to open state. As the user applies force to the first rotary member, the cams progressively disengage in a controlled manner, distributing the mechanical stress over time and preventing sudden force spikes that could damage the display.

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

Solution Approach 2:

The cam mechanism provides dynamic force modulation during the opening process. The geometry of the cam surfaces is designed to vary the mechanical advantage throughout the rotation, providing higher mechanical advantage at the beginning of the opening motion when the elastic force is strongest, and reducing the required force as the device approaches the fully open state, thereby protecting the display from excessive force.

Inventive Principle:
Principle #15Dynamics

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 hinge structure allows easy release of the closed state with one hand, reducing pressure on the display and preventing damage, while maintaining a secure hold at various angles.

Implementation Method 1

uses an elastic member in relation to the cam structure for generation of an elastic force (or a frictional force) for cam operation

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

uses an elastic member in relation to the cam structure for generation of an elastic force (or a frictional force) for cam operation

Methodology Applied
Scientific EffectFrictional force: Friction

Data Source

PatentEP4175265B1Hinge structure and foldable electronic device comprising same
Publication Date: 2025.08.06 SAMSUNG ELECTRONICS CO LTD
  • EP4175265B1 patent drawingFigure 1A
  • EP4175265B1 patent drawingFigure 1B
  • EP4175265B1 patent drawingFigure 2

AI summary

Disclosed is a foldable electronic device including a flexible display, a first housing and a second housing, a hinge housing, and a hinge structure. The hinge structure includes a first rotary member coupled to the first housing, a second rotary member coupled to the second housing, a first arm part coupled to the first rotary member and including a first rotary cam, a second arm part coupled to the second rotary member and including a second rotary cam, a fixed cam part including a first fixed cam engaged with the first rotary cam, a second fixed cam engaged with the second rotary cam, and a cam body connecting the first fixed cam and the second fixed cam, a stopper that restricts rotational angles of the arm parts, and an additional structure disposed between the stopper and the fixed cam part.