Telescopic Column Tube with Integrated Rotation-Preventing Protrusions

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Solution Overview

Problem

Existing methods for manufacturing telescopic columns in height-adjustable furniture are costly and inefficient in preventing rotation between concentric tubes, which can lead to unstable furniture due to twisting of the tubes.

Innovation Solution

A method involving a first elongated tube with a circular cross-section and a protrusion on its inner side, produced from a folded and bent metal sheet, which cooperates with protrusions on a second tube to prevent rotation without the need for external welding, allowing for seamless and cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flat elongated part is welded onto the inner side of the first elongated tube to prevent rotation, then rotation prevention is achieved, but production cost and manufacturing complexity increase

Engineering Contradiction:
Improverotation preventionVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The rotation prevention protrusion is integrated directly into the tube wall structure during the extrusion process, merging the rotation prevention function with the tube structure itself, eliminating the need for separate welding operations and reducing production cost

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extrusion process simultaneously creates both the tubular structure and the rotation prevention protrusions, making the manufacturing process multi-functional and reducing overall manufacturing complexity

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

2Reliability

If a flat elongated part is welded onto the inner side of the first elongated tube to prevent rotation, then rotation prevention is achieved, but manufacturing time increases

Engineering Contradiction:
Improverotation preventionVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The rotation prevention protrusions are formed during the initial extrusion process rather than being added later through welding, performing the rotation prevention function preparation in advance and eliminating subsequent manufacturing steps

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The tube formation and protrusion creation are combined into a single extrusion operation, reducing the total number of manufacturing steps and decreasing production time

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If protrusions are added to prevent rotation between concentric tubes, then stability is improved, but device complexity increases

Engineering Contradiction:
ImprovestabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protrusions are created as localized features on the inner surface of the tube wall, adding rotation prevention functionality only where needed without complicating the overall tube structure

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The protrusions are formed as an integral part of the tube wall during extrusion, combining the rotation prevention feature with the basic tube structure rather than adding it as a separate component

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3515249B1Manufacturing methods of elongated tubes, elongated tubes and telescopic columns of height-adjustable furniture
Publication Date: 2020.07.08 KINNARPS AB
  • EP3515249B1 patent drawingFigure 1~2
  • EP3515249B1 patent drawingFigure 3a
  • EP3515249B1 patent drawingFigure 3b

AI summary

The present disclosure describes a telescopic column (1) for height- adjustable furniture, the column comprising an outer elongated tube (10) and an inner elongated tube (20), the inner tube being arranged to move into and out of the outer tube so as to adjust the length of the telescopic column. Further, the outer tube (10) has a protrusion arranged on its inner side so as to co-operate with corresponding protrusions arranged on the outer side of the inner tube (20) in order to prevent rotation between the inner tube (20) and the outer tube (10). The outer tube including its rotation-preventing protrusion is produced in one piece, starting from a flat material sheet. Further, a method for producing such an outer tube in one piece starting from a flat material sheet is described.