Folding Door Fitting With Retractable Contact Stop

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Solution Overview

Problem

Existing furniture designs with movable parts lack effective stops that prevent deep insertion, undesired movements, and compromise compact design due to rigid, visible fittings that occupy space when open or create gaps when closed.

Innovation Solution

A flexible fitting with an adjustable contact part that pivots between contact and rest positions, using an energy accumulator to ensure proper alignment and support, minimizing noise and wear, and allowing for adjustable length to accommodate tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid stop is used on folding sliding doors, then the door is supported in the closed position, but the stop occupies space between door leaves when open, preventing compact parallel positioning

Engineering Contradiction:
Improvesupport function in closed positionVSAvoidspace between door leaves when open
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The stop is designed as a movable component that can pivot between a first position (extending toward the door leaf to provide support in closed position) and a second position (retracted to minimize space occupation when door is open). This dynamic repositioning allows the stop to adapt its function based on the door's state, resolving the contradiction between providing support and occupying space.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stop is divided into multiple segments or components that can move relative to each other. The main body remains fixed while the support element can be extended or retracted independently, allowing the stop to provide support when needed while minimizing its footprint when not in use.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the stop is positioned to bridge the gap between door and furniture body in closed position, then support is provided, but the same stop would be in the way when door leaves are parallel in open position

Engineering Contradiction:
Improvegap bridging capabilityVSAvoiddoor leaf alignment in open position
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The stop incorporates a movable support element that can pivot or extend/retract based on the door's position. When the door is closed, the support element extends to bridge the gap between the door and furniture body. When the door is open and leaves are parallel, the support element retracts or pivots to a reposition where it no longer interferes with the alignment, thus resolving the contradiction between gap bridging and ease of operation.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If fixed-length stops are used, then installation is simple, but tolerances on furniture body and door leaves cannot be compensated

Engineering Contradiction:
Improveinstallation simplicityVSAvoidtolerance compensation
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The stop includes an adjustable mechanism that allows the length or position of the support element to be modified during installation or operation. This could involve threaded adjustments, sliding components, or pivot points that can be positioned at different angles, enabling the stop to compensate for manufacturing tolerances in both the furniture body and door leaves while maintaining relatively simple installation procedures.

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 fitting ensures stable, space-saving operation of movable furniture parts by maintaining uniform gaps and reducing noise and wear, facilitating compact design and easy installation.

Implementation Method 1

using an energy accumulator to ensure proper alignment and support

Methodology Applied
Scientific EffectEnergy accumulator: Accumulator (energy)

Implementation Method 2

The energy accumulator can be formed, for example, by a gas spring, an elastomer or preferably by a spring, particularly preferably by a tension spring

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3622152B1Fitting for a folding door
Publication Date: 2025.09.17 JULIUS BLUM GMBH
  • EP3622152B1 patent drawingFigure 1~2
  • EP3622152B1 patent drawingFigure 3~5
  • EP3622152B1 patent drawingFigure 6~8

AI summary

The invention relates to a fitting (1) for a folding door (3) arranged on a furniture carcass (40) having at least one first door leaf (3a) and a second door leaf (3b) connected thereto in a jointed manner, wherein the fitting (1) has a contact part (2) arranged on the first or second door leaf (3a, 3b), wherein the contact part (2) is movably arranged between a contact position (K) and a rest position (R) on the first or second door leaf (3a, 3b), wherein, in a closed position (S) of the folding door (3), the contact part (2) in contact position (K) can be brought into contact with the furniture carcass (40) or a component of the furniture carcass (40) and, in an open position (O) of the folding door (3), the contact part (2) in a rest position (R) is movable in an intermediate chamber (Z) between the first and the second door leaf (3a, 3b).