Foldable Furniture Joint With Stop Lock Against Overstretching

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Solution Overview

Problem

Existing foldable furniture joints lack stability, particularly in slatted frames, leading to overstretching and damage when folded, and are difficult to secure in an extended position, which affects the portability and durability of collapsible furniture.

Innovation Solution

A joint design featuring angled sheet metal fittings with a rotatable shackle and stop mechanism that prevents overstretching by locking into place with safety pins, ensuring stability and secure extension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a joint is designed to connect foldable furniture parts, then the portability is improved, but the stability of the connection deteriorates

Engineering Contradiction:
ImproveportabilityVSAvoidstability of connection
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The joint incorporates a rotatable shackle that allows dynamic adjustment between folded and extended positions, while the stop mechanism provides static stability when extended. The shackle can rotate to accommodate folding movements but is limited by the stop to prevent overextension, thus achieving both portability and stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stop mechanism is designed to prevent overstretching of the joint before damage can occur. By providing a predetermined limit to the extension movement, the stop counteracts the tendency of the joint to be overstretched during folding operations, thus preventing damage in advance.

Inventive Principle:
Principle #9Preliminary anti-action

2Reliability

If the joint is designed with sufficient stability, then overstretching is prevented, but the device complexity increases due to additional components

Engineering Contradiction:
Improveprevention of overstretchingVSAvoidjoint structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The stop mechanism is integrated into the existing joint structure rather than being a separate additional component. The stop is positioned on one of the fittings and works in conjunction with the shackle's natural rotation, merging the stability function with the existing joint components to minimize overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The joint structure itself provides the stopping mechanism through its geometric configuration. The stop is formed as part of the fitting structure, and the shackle's rotation naturally engages with this stop without requiring external control systems or additional active components, allowing the structure to regulate its own movement.

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If the joint uses simple sheet metal fittings, then manufacturing cost is reduced, but the stability and durability deteriorate

Engineering Contradiction:
Improvemanufacturing costVSAvoidstability of joint
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The sheet metal fittings are designed with specific geometric parameters including angled configurations and strategically positioned stops. These parameter changes in the shape and orientation of the fittings enhance their structural performance and stability without changing the material type or manufacturing process, maintaining cost-effectiveness while improving strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The joint combines multiple sheet metal components (fittings, shackle, stop) into a composite structural system. The interaction between these components creates a synergistic effect where the overall joint strength exceeds what any single component could provide alone, achieving high stability through component integration rather than material enhancement.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2389842B1Joint and collapsible item of furniture
Publication Date: 2016.12.21 HETTICH FRANKE
  • EP2389842B1 patent drawingFigure 1
  • EP2389842B1 patent drawingFigure 2
  • EP2389842B1 patent drawingFigure 3~4

AI summary

The hinge (1) comprises a fitting (2,3) and a flap (4) which is connected at the ends of the fitting in a rotating manner. The fitting comprises an arrester in the area of its ends partially covered by the flap in a stretched position of the hinge. The arrester protrudes from the level of the flap, where the arrester is connected to the flap in the stretched position of the hinge. An independent claim is also included for folded furniture, particularly a slatted frame with a folding element.