Undercut Groove Connectors for Damage-Free Component Assembly

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Solution Overview

Problem

Existing groove milling devices struggle to produce grooves with undercut sections efficiently, particularly in hard materials like hardwood and metal, where self-tapping edges often damage the components and require excessive force, and existing connecting means fail to securely connect components without risking damage during assembly.

Innovation Solution

A groove milling device with a milling disk that can be rotated about an axis of rotation, featuring a stop for limiting groove depth and a lifting device for automatically actuating the milling disk to create undercut sections, and a connecting means with non-self-tapping retaining projections and curved support surfaces for secure anchoring without damaging the components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If self-tapping projecting edges are used to drive fitting halves into components, then the connecting elements can be anchored in the components, but the side walls of the components may break away and excessive force is required

Engineering Contradiction:
Improveanchoring strengthVSAvoidcomponent damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

Instead of driving the connecting element into the component using self-tapping edges that push material ahead, the groove is pre-formed with an undercut section that allows the connecting element to be inserted and then locked in place. The undercut geometry reverses the traditional anchoring approach by creating mechanical interlocking after insertion rather than during insertion.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The groove with undercut section is pre-formed in the component before the connecting element is inserted. This preliminary preparation of the receiving structure eliminates the need for forceful insertion and prevents damage during the anchoring process.

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If self-tapping edges are used to clear retaining grooves, then connecting elements can be inserted, but very considerable effort is required and material can flake off

Engineering Contradiction:
Improveinsertion processVSAvoidassembly time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The groove with undercut section is pre-formed in the component before assembly, eliminating the need for time-consuming self-tapping clearance operations during assembly. The retaining groove is prepared in advance with the exact geometry needed for the connecting element.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The function of clearing the retaining groove is extracted from the insertion process itself and performed separately as a pre-processing step. This separates the groove preparation from the connecting element insertion, allowing each to be optimized independently.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If fitting halves are hammered into components, then anchoring is achieved, but position correction is no longer possible

Engineering Contradiction:
Improveanchoring strengthVSAvoidposition correction
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connecting element is designed with a curved support surface that matches the curved undercut surface, allowing tangential movement during insertion for position correction. Once inserted, the geometry provides positive connection and anchoring. This dynamic approach allows adjustment during the insertion process while maintaining final stability.

Inventive Principle:
Principle #15Dynamics

4Reliability

If grooves with undercut sections are produced in hard materials, then secure connections are possible, but existing milling devices struggle with efficiency and damage risk

Engineering Contradiction:
Improveconnection securityVSAvoidmilling efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The groove milling process is segmented into two distinct operations: first milling the base groove to a predetermined depth, then lifting the milling disk to mill the undercut section. This segmentation allows each operation to be optimized independently and enables efficient production of complex groove geometries in hard materials.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The base groove is pre-milled to a predetermined depth before the undercut section is created. This preliminary preparation allows the subsequent undercut milling to be performed efficiently with the lifting device, ensuring precise geometry while maintaining high productivity in hard materials.

Inventive Principle:
Principle #10Preliminary action

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 groove milling device enables precise and efficient production of grooves with undercut sections in various materials, reducing the risk of component damage and allowing for secure connections with positional corrections, enhancing assembly precision and ease.

Implementation Method 1

a milling disk (140) which can be rotated about an axis of rotation (142) for milling a groove (110) in a component (102, 104)

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP1989956B1Connecting device and method for creating a connection between a first component and a second component
Publication Date: 2015.09.02 LAMELLO AG
  • EP1989956B1 patent drawingFigure 1~2
  • EP1989956B1 patent drawingFigure 3~4
  • EP1989956B1 patent drawingFigure 5

AI summary

A connecting means for connecting a first component and a second component, in particular for connecting furniture or machine parts, comprising a first connecting element arranged on the first component when the components are connected and a second connecting element arranged on the second component when the components are connected , which enables two components made of a variety of materials to be securely connected to one another without causing the risk of damage to the two components during assembly, it is proposed that at least one of the connecting elements comprises at least one non-self-tapping retaining projection which has a curved support surface, which is arc-shaped in a longitudinal section, wherein the holding projection can be inserted into a groove provided on one of the components with a curved undercut surface, which is arc-shaped in a longitudinal section.