Rib Screw Connection With Connecting Body to Prevent Sink Marks

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Solution Overview

Problem

Existing screw connections, particularly in plastic parts, face issues with ventilation and cooling during the production of screw domes, leading to optical defects such as sink marks and shiny spots, and lack flexibility, stability, and ease of assembly and disassembly.

Innovation Solution

A screw connection featuring a rib-shaped or plate-shaped connection region on one component with a connecting body that includes a bore and an abutment section, allowing a self-tapping or thread-forming screw to cut threads directly into the first component, providing a secure and releasable connection without the need for auxiliary elements and accommodating screws of various diameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If self-tapping or thread-forming screws are used directly in through-holes or screw bosses, then the connection strength is improved, but ventilation and cooling problems occur during production leading to optical defects

Engineering Contradiction:
Improveconnection strengthVSAvoidoptical defects (sink marks and shiny spots)
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The connection system is divided into three functional parts: a connecting body with bore, a self-tapping screw, and a component with connection area. This segmentation allows the connecting body to be designed with optimized geometry that prevents ventilation problems while maintaining connection strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting body acts as an intermediary element between the component and the screw. It provides a bore that guides the screw and distributes loads, preventing direct stress concentration that causes sink marks and shiny spots in the component.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If auxiliary elements such as threaded bushings or sheet metal nuts are used, then connection stability is improved, but device complexity and manufacturing effort increase

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

Solution Approach 1:

The connecting body combines multiple functions into a single element: it provides the bore for the screw, the abutment section for load bearing, and the connection interface for the component. This eliminates the need for separate threaded bushings or sheet metal nuts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The connecting body is designed as a universal component that can be used with different screw diameters and component types. The bore can accommodate various screw sizes, and the connection area can be adapted to different component geometries, reducing the need for multiple specialized auxiliary elements.

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

3Strength

If the bore in the connecting body projects over the first component, then the screw can cut threads directly into the component improving hold strength, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvehold strengthVSAvoidbore projection precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The connecting body is pre-assembled onto the component before the screw is inserted. The bore is positioned and projected over the component in advance, so that when the self-tapping screw is inserted, it automatically cuts threads at the correct location and depth, reducing precision requirements during the final assembly step.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bore diameter and projection length are optimized as specific parameters. The bore diameter is slightly larger than the screw diameter to allow easy insertion, while the projection length is sufficient to allow the screw to cut threads into the component but not so long as to cause misalignment. These parameter optimizations reduce manufacturing precision requirements.

Inventive Principle:
Principle #35Parameter changes

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 solution offers a stable, flexible, and easy-to-produce screw connection that ensures a tight hold, is reusable, and reduces manufacturing effort, while eliminating ventilation and cooling issues during production, thus preventing optical defects and enhancing the connection's strength and stability.

Implementation Method 1

a self-tapping or thread-forming screw, and a second component (2). The second component (2) is fixedly connected to the connecting body (4) and the first component (1) by means of the screw (5)

Methodology Applied
Scientific EffectSelf-tapping or thread-forming: Screw

Data Source

PatentEP4425002A1Screw connection
Publication Date: 2024.09.04 AKO KUNSTE ALFRED KOLB
  • EP4425002A1 patent drawingFigure 1~4
  • EP4425002A1 patent drawingFigure 5~8
  • EP4425002A1 patent drawingFigure 9~12

AI summary

The invention describes a screw connection for the fixed connection of two components (1, 2) to one another, and comprises a first component (1) having a rib-shaped connecting area (3) on one edge (14), a connecting body (4) fixedly arranged on this connecting area (3), a self-tapping screw (5), and a second component (2). The second component (2) is fixedly connected to the connecting body (4) and the first component (1) by means of this screw (5). The connecting body (4) has a bore along the first side (7) of the first component (1) and a bearing section (8) arranged on the second side (9) of the first component (1), opposite the first side (7). The connecting body (4) has a slot-like recess (10) on the bearing section (8) through which the first component (1) passes.The bore (6) in the connecting body (4) protrudes beyond the first component (1) in such a way that the screw (5) screwed into it is screwed into the first component (1) in a thread (11) formed by it.