Stackable Chair with Nested Armrest Design for Simplified Row Assembly

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Solution Overview

Problem

Existing stackable chairs with armrests that are assembled in a row face challenges due to complex and precise tilting movements required for assembly, which can be difficult to achieve and lead to increased material usage and assembly steps, particularly when using plastic reinforced with metal rods, resulting in an ecological and manufacturing inefficiency.

Innovation Solution

A stackable chair design featuring two lateral structures with armrests that extend rearwardly and rear uprights, allowing for easy assembly by nesting one chair into another, with defined lengths and inclinations of armrests and rear uprights, and a configuration that prevents relative movement along the transverse axis without additional parts, using a set of one-piece tubes for structural support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the chair uses complex tilting movement for assembly, then the chairs can be assembled in a row without additional connecting elements, but the assembly becomes difficult and requires high precision manufacturing

Engineering Contradiction:
Improverow assembly capabilityVSAvoidassembly difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent implements nesting by allowing one chair to be placed inside another chair in a row configuration. The armrest and front leg of one chair extend between the corresponding elements of adjacent chairs, creating a nested arrangement that enables row assembly without additional connecting elements while simplifying the assembly operation.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If the armrests are made of plastic reinforced with metal rod, then they can be manufactured by molding, but this increases the number of parts and assembly steps

Engineering Contradiction:
Improvemolding capabilityVSAvoidnumber of parts
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the armrest and front leg into a single integrated element that forms one continuous structure. This consolidation reduces the number of separate parts that need to be manufactured and assembled, while still allowing for molding-based production of the combined component.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the armrests extend to the level of the backrest, then user comfort is ensured, but the assembly in a row becomes more complex

Engineering Contradiction:
Improveuser comfortVSAvoidassembly complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent resolves the conflict by extending the armrest and front leg assembly in the longitudinal direction (along the row) rather than merely in the vertical dimension. This dimensional extension allows the armrest to provide comfort at backrest level while the nested configuration manages the complexity of row assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Manufacturing precision

If the curved parts are made with high precision, then the chair assembly in a row is enabled, but the manufacturing becomes less environmentally friendly

Engineering Contradiction:
Improvecurved part precisionVSAvoidenvironmental impact
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the geometric parameters of the curved parts to enable assembly through a nesting mechanism rather than requiring high-precision curved surface matching. This parameter change reduces manufacturing precision requirements and associated environmental impacts while maintaining the row assembly capability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4223185B1Chair which can be stacked and assembled in a row
Publication Date: 2024.12.04 MAHBER
  • EP4223185B1 patent drawingFigure 1
  • EP4223185B1 patent drawingFigure 2
  • EP4223185B1 patent drawingFigure 3

AI summary

Stackable chair (1) the chair (1) comprising a seat (3), a backrest (2), a first lateral structure (LR) and a second lateral structure (LL), each comprising: ▪ a front leg (PaR, PaL) and a rear leg (PdR, PdL) located behind the front leg (PaR, PaL) along an x-axis of the chair extending from the rear to the front, ▪ an armrest (AR, AL) extending straight from a first curved part (CAR, CAL) to a second curved part of the structure (CDR, CDL), the armrest (AR, AL) extending rearward away from a first longitudinal vertical plane located between the armrests of the two lateral structures.