Telescopic Column with Custom-Made Sliding Elements to Minimize Play

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Solution Overview

Problem

Existing telescoping columns used in height-adjustable furniture face challenges in maintaining stability and minimizing play between tubes, requiring complex assembly and a variety of sliding elements to account for manufacturing tolerances, leading to time-consuming fine adjustments.

Innovation Solution

Custom-made sliding elements with predetermined material thicknesses, produced through 3D printing or machining, are used between the inner and outer tubes, featuring coding projections and fastening elements to ensure precise fit and assembly, reducing play and eliminating the need for multiple sliding element thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If sliding elements of varying thicknesses are used to minimize play, then manufacturing precision is improved, but assembly time increases and device complexity worsens

Engineering Contradiction:
Improveplay-free arrangementVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The sliding elements are pre-adjusted to different thicknesses during manufacturing, so that the correct thickness is already determined before assembly. This eliminates the need for time-consuming on-site adjustment and allows for quick assembly by simply selecting and installing the pre-adjusted elements.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The sliding elements are divided into multiple individual components, each with a specific predetermined thickness. This segmentation allows for selective use of different thicknesses to compensate for manufacturing tolerances in the tubes, achieving a play-free arrangement without requiring complex adjustment mechanisms.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If sliding elements of varying thicknesses are used to minimize play, then manufacturing precision is improved, but device complexity worsens

Engineering Contradiction:
Improveplay-free arrangementVSAvoidstock of sliding elements
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sliding elements are segmented into discrete thickness variants, each designed for specific tolerance ranges. This allows for a manageable inventory of standardized thicknesses rather than requiring continuous adjustment capabilities, simplifying the overall device complexity while maintaining precision.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If grinding sliding elements to desired thickness is used, then manufacturing precision is improved, but productivity worsens

Engineering Contradiction:
Improveproper fitVSAvoidassembly speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The sliding elements are pre-adjusted to the correct thickness during the manufacturing process rather than requiring post-manufacturing grinding or adjustment. This preliminary action ensures proper fit is achieved before assembly, eliminating time-consuming on-site adjustments and significantly improving assembly productivity.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If adjustable sliding shoes with wedge elements are used, then manufacturing precision is improved, but device complexity and assembly time worsen

Engineering Contradiction:
Improvesubsequent adjustmentVSAvoidscrew connection mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The complex adjustment mechanism (screw connection and wedge elements) is removed from the design. Instead, simple sliding elements with predetermined thicknesses are used, which are installed by straightforward insertion without requiring additional adjustment mechanisms, thereby reducing device complexity while maintaining precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3302178B1Telescopic column having sliding elements
Publication Date: 2020.03.25 STEELCASE INC
  • EP3302178B1 patent drawingFigure 1
  • EP3302178B1 patent drawingFigure 2
  • EP3302178B1 patent drawingFigure 3~4B

AI summary

The invention relates to a telescopic column (1) having an outer tube (2) and at least one first inner tube (3), wherein the at least one first inner tube (3) is equipped with a plain bearing (5), which has a first sliding set (6), which comprises a plurality of sliding elements (61, 62,..., 6n), which are arranged between the first inner tube (3) and the outer tube (2) in the circumferential direction on the outer wall (8) of the first inner tube (3), by means of which sliding elements the two tubes (2, 3) are guided in such a way that the two tubes can be slid longitudinally in relation to each other. At least some or all of the sliding elements (61, 62,..., 6n) are custom-made and have a contact and/or sliding surface (9) that is a) worked, milled, and/or ground down to a specified material thickness or b) built up and/or printed to the specified material thickness by means of a 3-D printer, wherein the specified material thickness is selected in such a way that the play of the first inner tube (3) in relation to the outer tube (2) lies below a threshold value, or preferably there is no play of the first inner tube in relation to the outer tube.