Hinge With Variable Transmission Ratio for Controlled Door Movement

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Solution Overview

Problem

Existing hinges for household appliances and furniture do not allow for a particularly advantageous actuation of doors, particularly for heavy doors, leading to issues such as rapid opening or slamming, and lack flexibility in accommodating different door weights.

Innovation Solution

A hinge design featuring a base element, hinge arm, transmission element, spring, and lever mechanism that allows for controlled pivoting of doors between open and closed positions, utilizing a guide system and spring force to manage door movement, with optional braking surfaces for deceleration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional hinge is used for heavy doors, then the door can be mounted, but the door opens rapidly or slams due to lack of control

Engineering Contradiction:
Improvedoor actuation controlVSAvoiddoor movement stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The hinge incorporates a transmission element with variable transmission ratio that changes during door movement. When the door is near the closed position, the transmission ratio provides higher braking torque to prevent rapid opening. As the door approaches the open position, the transmission ratio adjusts to maintain controlled movement throughout the entire range of motion, preventing slamming.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The hinge uses a spring element whose force characteristic changes with compression distance, providing progressive resistance to door movement. The spring is initially compressed to store energy, and as the door moves, the spring force varies dynamically to control the door's acceleration and deceleration, ensuring stable movement at all positions.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a hinge is designed for heavy doors, then door control improves, but the hinge cannot accommodate lighter doors effectively

Engineering Contradiction:
Improvedoor movement controlVSAvoiddoor weight range accommodation
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The hinge is designed with adjustable parameters including spring pre-compression force, transmission element dimensions, and pivot arm lengths. These parameters can be modified to match different door weights, allowing the same hinge design to accommodate everything from light cabinet doors to heavy appliance doors by simply adjusting the mechanical parameters rather than redesigning the entire mechanism.

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

3Reliability

If spring force is increased to control heavy doors, then door opening control improves, but the force required to open the door increases

Engineering Contradiction:
Improvedoor opening controlVSAvoidforce to open door
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The transmission element is designed with a variable transmission ratio that is highest when the door is near the closed position and decreases as the door opens. This allows the spring force to be effectively amplified when needed most (at the beginning of opening) while requiring less force as the door approaches the open position, creating a natural easing of the opening effort throughout the motion.

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

Enables secure, comfortable, and efficient operation of doors with varying weights, preventing excessive opening or closing speed, and allowing for easy adaptation to different door weights, thus providing a wide range of applications.

Implementation Method 1

The hinge (20) also has a spring (44), and an actuating element (46) coupled to the spring (44). The actuating element (46) is guided and displaceable along a guide (52) of the base element (24) in such a way that the spring (44) can be tensioned and relaxed by moving the actuating element (46) along the guide (52) and thus relative to the base element (24).

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The hinge (20) also has a braking surface (74) which exerts a frictional force, in particular directly, on the transmission element (34) as a braking force

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4375466B1Hinge for a device, in particular for a domestic appliance or a piece of furniture, and device, in particular domestic appliance or piece of furniture
Publication Date: 2025.11.05 BSH HAUSGERATE GMBH
  • EP4375466B1 patent drawingFigure 1~2
  • EP4375466B1 patent drawingFigure 3a~3b
  • EP4375466B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a hinge (20) for a device (10), comprising a base element (24), a hinge arm (30) which is pivotably connected to the base element (24) about a first pivot axis (32) relative to the base element (24), a transmission element (34) which is rotatably held on the base element (24) about a rotation axis (36) relative to the base element (24), a spring (44), and an actuating element (46) coupled to the spring (44), which is pivotally coupled to the transmission element (34) and is guided and displaceable along a guide (52) of the base element (24), such that the spring (44) can be tensioned and released by moving the actuating element (46) along the guide (52).