Height-Adjustable Table Leg Assembly Without Welded Joints

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Solution Overview

Problem

Existing height-adjustable table legs and frames are not produced cost-effectively, as they rely on expensive joining techniques like welding.

Innovation Solution

The use of form-fitting and positive locking mechanisms, such as recesses and tabs, in telescopic elements to hold receiving and closure plates, along with a two-part holder for the threaded element, reduces the need for costly joining techniques like welding, allowing for more cost-effective production and easier assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding joining techniques are used to assemble telescopic elements and plates, then structural strength and reliability are improved, but manufacturing cost increases and production efficiency decreases

Engineering Contradiction:
Improvestructural strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent replaces welding (a thermal/mechanical joining process) with a mechanical form-fitting connection system. The receiving elements with recesses and tabs create a snap-fit assembly that eliminates the need for welding operations, reducing manufacturing cost and complexity while maintaining structural integrity through precise geometric interlocking.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent divides the table leg into separate modular components (telescopic elements, receiving elements, closure plates) that can be manufactured independently and assembled through form-fitting connections. This segmentation allows each component to be optimized and manufactured separately, reducing overall manufacturing cost and enabling easier assembly compared to welded construction.

Inventive Principle:
Principle #1Segmentation

2Reliability

If welding joining techniques are used to assemble telescopic elements and plates, then structural reliability is improved, but assembly time and production efficiency decrease

Engineering Contradiction:
Improvestructural reliabilityVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The receiving elements are pre-formed with integrated recesses and tabs during manufacturing. These pre-configured geometric features enable rapid snap-fit assembly of the telescopic elements and plates without requiring on-site welding operations, significantly improving production efficiency while maintaining reliable structural connections.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If form-fitting and positive locking mechanisms are used instead of welding, then manufacturing cost decreases and assembly is simplified, but manufacturing precision requirements increase

Engineering Contradiction:
Improvemanufacturing costVSAvoidform-fitting precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies form-fitting connections only at specific critical locations (receiving elements, closure plates) rather than requiring precision throughout the entire structure. The recesses and tabs are localized geometric features that concentrate precision requirements to specific areas, making the overall manufacturing process more cost-effective while maintaining adequate structural reliability.

Inventive Principle:
Principle #3Local quality

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 approach enables the production of height-adjustable frame parts and table frames at a lower cost while simplifying the assembly process, making them more economically viable and efficient.

Implementation Method 1

a height adjustment mechanism in the telescopic elements, the height adjustment mechanism comprising a threaded rod which extends in the telescopic elements, wherein the threaded rod is guided in a thread of a threaded element

Methodology Applied
Scientific EffectThreading: Screw

Implementation Method 2

an upper end of the threaded rod is mounted in a bearing in a receiving element in an upper one of the telescopic elements from the receiving elements so that it can rotate upwards about its longitudinal axis

Methodology Applied
Scientific EffectBearing: Ball Bearing

Data Source

PatentEP3189748B1Height adjustable frame parts for a piece of furniture, in particular a height-adjustable table leg, and height-adjustable single or multi-column table frame
Publication Date: 2018.07.25 OELSCHLAGER METALLTECHN
  • EP3189748B1 patent drawingFigure 1
  • EP3189748B1 patent drawingFigure 2
  • EP3189748B1 patent drawingFigure 3

AI summary

Height-adjustable frame part for a piece of furniture, in particular a height-adjustable table leg, comprising at least two rectangular telescopic elements that can be telescoped axially into one another and a height-adjustment mechanism in the telescopic elements, the height-adjustment mechanism comprising a threaded rod that extends in the telescopic elements, the threaded rod in a thread of a threaded element in a lower of the telescopic elements, a lower end of the threaded rod is free and an upper end of the threaded rod is mounted in a bearing in a receiving element in an upper one of the telescopic elements projecting upwards from the receiving element so that it can rotate about its longitudinal axis, characterized in that the receiving element in the upper telescopic element is held in a form-fitting manner.