Mitered Metal Leg Joint Structure for Transverse Load Stability

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Solution Overview

Problem

Metal legs with miter-welded connections are prone to failure under transverse loads, especially when the leg and foot do not form a right angle, limiting design flexibility and stability.

Innovation Solution

The leg's inner corner at the miter joint is extended with a supporting wall section that engages with the foot's recess, distributing loads beyond the weld seam and enhancing resilience, with optional support stops and plug-in receptacles for added stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a miter-welded connection is used between leg and foot, then the butt joint is less visible and design freedom is improved, but the weld seam cannot withstand greater transverse loads and stability deteriorates

Engineering Contradiction:

Improveaesthetic appearance of connectionVSAvoidresistance to transverse loads

Core Design Contradiction:

ShapeVSStrength

Solution Approach 1:

The connection structure is segmented into multiple load-bearing paths: the weld seam for basic connection and the extended wall section for transverse load transfer. This segmentation allows each component to specialize in its optimal function while maintaining overall structural integrity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The load transfer mechanism is extended from the traditional two-dimensional weld seam into the third dimension by creating an extended wall section that projects into the foot's hollow space. This dimensional extension provides additional surface area for load distribution without compromising the external aesthetic appearance.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the leg and foot form an acute angle instead of a right angle, then design flexibility is improved, but transverse loads increase and weld seam reliability deteriorates

Engineering Contradiction:

Improvedesign flexibility of leg angleVSAvoidconnection reliability under increased lateral forces

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The extended wall section is strategically positioned at the inner corner of the acute angle connection, where transverse loads are most critical. This localized reinforcement provides targeted strength enhancement exactly where needed, allowing the overall acute angle design to maintain both flexibility and reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The extended wall section acts as a pre-positioned structural element that anticipates and prepares for transverse load conditions. By being in place before loading occurs, it prevents stress concentration at the weld seam and distributes forces evenly throughout the connection.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP2868231B1Metal leg for an armchair or table

Publication Date: 2016.03.16 MAYR SCHULMOBEL MBH

Figure 1~2
Figure 3

AI summary

A metal leg for a chair or table with a hollow leg and a hollow foot (1, 2) is described, which is welded to the leg (1) via a miter (3). In order to enable greater stability in the event of transverse loads on the leg, it is proposed that the wall of the leg (1) in the area of the inner corner (4) forming a right or acute angle (α) between the leg and foot (1, 2) should have a the miter (3) has an extended wall section (5) which is supported on the opposite wall of the leg (2).