Tube Snap Flange Forming for Smooth Collar Fastening

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Solution Overview

Problem

Existing fastening techniques for telescopic tube arrangements often leave marks on the surface, add thickness, or weaken the joint due to the use of screws, nails, rivets, gluing, welding, or soldering, which are undesirable for applications requiring smooth surfaces and strength.

Innovation Solution

A method involving a forming punch to create a snap portion or flange on the tube by locally reducing the material thickness, allowing a collar with a receiving portion to engage securely without altering the outer surface, using a forming punch to relocate material and form a flange that fits within the collar's receiving portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If penetrating fastening elements such as screws, nails and rivets are used to fasten the collar to the tube, then the collar is securely fastened to the tube, but marks are left on the surfaces of both parts and the local thickness is increased

Engineering Contradiction:
Improvefastening strengthVSAvoidsurface smoothness
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention merges the fastening function with the tube material itself by forming an integral flange directly from the tube wall. This eliminates the need for separate fastening elements (screws, nails, rivets) that would leave marks and increase local thickness. The flange is formed by displacing material within the tube wall, creating a seamless integration that maintains surface smoothness while providing secure collar attachment.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention extracts the fastening function from external fastening elements and relocates it to an integral flange formed from the tube material itself. By taking out the need for separate fasteners and embedding the fastening capability directly into the tube structure, the solution eliminates surface marks and avoids increasing local thickness, while still achieving secure collar attachment.

Inventive Principle:
Principle #2Taking out (Extraction)

2Shape

If press fit is used to arrange the collar on the tube, then the surface remains smooth, but the collar loosens and wears off over time due to rubbing against the inner tube

Engineering Contradiction:
Improvesurface smoothnessVSAvoidcollar retention
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The invention introduces a curved or hooked flange geometry that engages with the collar in a interlocking manner. The flange is formed with a shape that extends into the tube hollow and hooks onto the collar's receiving portion, creating a mechanical interlock that prevents loosening and wear. This curved geometry provides positive engagement while maintaining the smooth outer surface of the tube.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If gluing, soldering or welding is used to attach the snap arrangement, then the collar can be secured to the tube, but the joining process affects the strength of the final product and leaves undesired marks on the outside

Engineering Contradiction:
Improvejoint strengthVSAvoidsurface appearance
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The invention makes the tube material self-service by using the tube's own material to form the flange through plastic displacement. This eliminates the need for external joining processes (gluing, soldering, welding) that would compromise joint strength or leave surface marks. The flange is created entirely from the tube material itself, providing a strong, mark-free attachment solution.

Inventive Principle:
Principle #25Self-service

4Strength

If additional fastening components are added to secure the collar, then the collar attachment is strengthened, but the manufacturing process becomes more complex and costly

Engineering Contradiction:
Improveattachment strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The invention combines the tube and flange into a single integrated component, eliminating the need for separate fastening parts. This merging reduces manufacturing complexity by removing multiple assembly steps and components, while simultaneously providing strong collar attachment through the integral flange structure that is formed directly from the tube material.

Inventive Principle:
Principle #5Merging (Combining)

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 method provides a smooth outer surface, enhances manufacturing efficiency, and maintains the tube's strength by using the original material to form the flange, ensuring a secure and invisible fastening arrangement without adding material or removing it from the surface.

Implementation Method 1

punching the tube with a forming punch at an inner radial part of an edge portion of the tube in the axial direction of the tube, locally reducing the tube thickness, so that the material being punched is plastically relocated in the axial direction

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3960317B1Method of manufacturing a tube snap fastening arrangement
Publication Date: 2023.07.12 ROL AB
  • EP3960317B1 patent drawingFigure 1
  • EP3960317B1 patent drawingFigure 2~3b
  • EP3960317B1 patent drawingFigure 4~5

AI summary

The invention relates to a method (100) for manufacturing a fastening arrangement for fastening a collar to a tube. The method comprises the steps of providing a hollow tube (10), arranging said tube for receiving at least one forming punch (30) in the axial direction of the tube, punching the tube with a forming punch at an inner radial part of an edge portion (16) of the tube in the axial direction of the tube, locally reducing the tube thickness, so that the material being punched is plastically relocated in the axial direction, locally forming a snap portion (11) in the form of a flange (12) in the radial direction towards the hollow inside of the tube, providing a collar (20) configured to be arranged on the tube, wherein the collar comprises at least one receiving portion (21) arranged to receive said snap portion, and arranging the collar to the tube such that the snap portion engages with said receiving portion.