Door Weight Compensation Mechanism With External Spring Tension Adjustment

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Solution Overview

Problem

Existing household appliances, such as dishwashers and ovens, face challenges in balancing the weight of doors with decorative covers, as conventional adjustment mechanisms require additional space and may not maintain tension without auxiliary elements.

Innovation Solution

A compact door adjustment mechanism using an endless screw and gearwheel system, where a pulling cable is wound around a spool without lateral displacement, allowing tension adjustment from the exterior and maintaining it until readjustment, utilizing durable plastic materials for the mechanism's parts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional adjustment mechanism is used to balance the door weight, then the door can be balanced, but the mechanism occupies additional space within the appliance

Engineering Contradiction:
Improvedoor balancingVSAvoidspace occupied by adjustment mechanism
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the adjustment mechanism components (spool, cable, spring) into a compact integrated assembly that occupies minimal space within the door hinge structure. The spool is mounted on the hinge axis, and the cable runs through a guided path, merging multiple functions into a single compact unit that does not require additional space within the appliance body.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adjustment mechanism utilizes the depth dimension of the hinge structure rather than requiring additional lateral or vertical space. The spool rotates around the hinge axis, and the cable is routed through a three-dimensional path that efficiently uses the available space within the hinge assembly, eliminating the need for external adjustment components.

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

2Stability of the object's composition

If the spring tension is adjusted to balance the heavier door with decorative cover, then the door remains stable, but conventional mechanisms require auxiliary elements to maintain tension

Engineering Contradiction:
Improvedoor stabilityVSAvoidnumber of auxiliary elements
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The spring-loaded cable tensioning system automatically maintains the required tension through the spring force. The spring is compressed or extended based on the door weight, and the cable tension is self-regulated without requiring auxiliary locking elements, clips, or adjustment mechanisms. The system serves itself by using the spring's elastic force to maintain constant tension as the door moves through its opening range.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent removes auxiliary tension-maintaining elements from conventional mechanisms and replaces them with a pure spring-loaded cable system. The cable is simply wound around the spool and allowed to tension the spring, eliminating the need for additional clips, locks, or adjustment devices that would increase device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of moving object

If a compact adjustment mechanism is used, then space is reduced, but the mechanism must still provide reliable tension adjustment from the exterior

Engineering Contradiction:
Improvespace used by mechanismVSAvoidexternal adjustment capability
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The hinge assembly serves multiple functions: it provides the door mounting, the rotation axis, and the adjustment mechanism housing. The spool is integrated into the hinge structure, and the same hinge components that enable door rotation also facilitate cable adjustment from the exterior. This multi-functionality eliminates the need for separate adjustment access points while maintaining ease of operation.

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

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

This solution provides a space-efficient and reliable method to adjust and maintain door spring tension, preventing door fall due to increased weight, without the need for additional elements, ensuring stable operation and reduced space usage within the appliance.

Implementation Method 1

a spring (9), balancing the weight of the door (3) by applying a tensile force on the hinge (4)

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a pulling cable (10) which is wound around a spool (11) rotated around a fixed axis by rotating the adjustment rod (6)

Methodology Applied
Scientific EffectMechanical winding: Wheel and Axle

Implementation Method 3

The fixing arrangement (16) comprises an endless screw (7) rotated by the adjustment rod (6) and a gearwheel (8) rotated by the endless screw (7)

Methodology Applied
Scientific EffectGear mechanism: Gear

Implementation Method 4

an endless screw (7) rotated by the adjustment rod (6)

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP1909631B1A household appliance with adjustment mechanism for the door weight compensation device
Publication Date: 2012.01.18 ARCELIK AS
  • EP1909631B1 patent drawingFigure 1~2
  • EP1909631B1 patent drawingFigure 3~4
  • EP1909631B1 patent drawingFigure 5~6

AI summary

The present invention relates to a household appliance (1) such as a dishwasher or an oven, the front door (3) of which is opened by pulling from the top downwards, comprising an adjustment mechanism (5) that balances the weight of the door (3) so that while the door (3) is being opened it doesn't fall by its own weight or closed in a hard way. The adjustment mechanism (5) comprises a spring (9) that applies a tensile force on the door (3), that is pulled to be tensioned by the pulling cable (10) which is activated by an adjustment rod (6), an endless screw (7) and a gearwheel (8).