Butt Connector with Cylindrical Plug-In Sections for Gap-Free Chipboard Joints

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Solution Overview

Problem

Existing connectors for joining chipboards require high joining forces and often result in gaps or incomplete fixation due to the softness of the chipboard material, especially when dealing with harder wood materials like MDF, which complicates the assembly process.

Innovation Solution

The connector parts are designed with rear plug-in sections having the same or approximately the same diameter over their axial length, eliminating the cone shape and incorporating features like support ribs, lugs, and transverse ribs to reduce joining forces and ensure secure engagement without gaps, allowing for easier assembly by pressing rather than impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rear plug-in sections have a conical shape to compress the chipboard, then the connector can be locked in place, but the joining forces required are very high and the chipboard may not be sufficiently compressed

Engineering Contradiction:
Improvelocking capabilityVSAvoidjoining force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent changes the geometric parameter of the rear plug-in sections from conical to cylindrical, eliminating the need for high compressive forces while maintaining reliable locking through the support rib mechanism

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conical compression function is extracted from the rear plug-in sections and transferred to the support ribs, which press into the soft end face of the chipboard to provide compression without requiring high joining forces

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If high joining forces are applied to compress the chipboard, then the cone deforms and edge scanning disappears, but this has a negative effect on practical application due to the effort required

Engineering Contradiction:
Improveedge scanning eliminationVSAvoidassembly effort
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The support ribs automatically press into the soft end face of the chipboard during assembly, self-regulating the compression to eliminate edge scanning without requiring high external forces from the user

Inventive Principle:
Principle #25Self-service

3Ease of operation

If the connector is designed to be inserted into pre-drilled holes, then the components can be joined, but the connector may fall out of the holes during pre-insertion

Engineering Contradiction:
Improvepre-insertion capabilityVSAvoidretention in hole
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The front plug-in sections are given a specific local quality with radially outwardly protruding lugs that engage with the hole walls, providing retention during pre-insertion while allowing smooth insertion

Inventive Principle:
Principle #3Local quality

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 design reduces joining forces by up to 50%, enhances user-friendliness, and ensures secure, gap-free connections between chipboards, improving practical application by eliminating the need for high assembly forces.

Implementation Method 1

The connector comprises two connector parts in the form of U-shaped brackets (2a, 2b) which can be pushed together into an assembly position (3) and lock in this position. The connector (1) is made of resiliently deformable plastic

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

When inserted into the hole in the chipboard, the conical rear plug-in sections are pressed together to the diameter of the hole, as a result of which the edge scanning within the hole disappears

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3692267B1Connector for butt connecting two components
Publication Date: 2022.04.20 HAEFELE SE & CO KG
  • EP3692267B1 patent drawingFigure 1a~2
  • EP3692267B1 patent drawingFigure 3~5b
  • EP3692267B1 patent drawingFigure 6~7

AI summary

The invention relates to a connector (1) for butt-connecting two components (21a, 21b), in particular two pieces of chipboard, comprising two connector parts which, when rotated by 90° relative to one another, can be pushed together, into one another, until they are in a locked assembly position, and which are in the form of U-shaped brackets (2a, 2b) having two outer bracket arms (3), each having a rear plug-in section (4) for introducing into a circular borehole (22a, 22b) of the one component (21a, 21b) and an expandable front plug-in section (5), forming the free bracket end, for introducing into a circular borehole (3a, 3b) of the other component (21a, 21b), comprising a central bracket arm (6) for expanding the two front plug-in sections (5) of the respective other bracket in the assembly position, and comprising at least one locking section (10, 11; 18, 19) for mutually locking the two brackets (2a, 2b) in the assembly position, wherein, according to the invention, the outer sides (8) of the rear plug-in sections (4) are each designed as partial casing surfaces of the same circular cylinder or at least approximately as partial casing surfaces of the same circular cylinder.