Chair Mechanical Subassembly for Tool-Free Pivot Assembly

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Solution Overview

Problem

Existing chair mechanical subassemblies are difficult to preassemble quickly and efficiently, requiring complex tool-based connections and additional preassembly steps, which increases production time and complexity.

Innovation Solution

A mechanical subassembly featuring a housing portion with flange means and a curved connection member that can be coupled tool-free, using integral construction and intermediate bearings for secure pivoting and adjustment, allowing for simple and rapid assembly without tools, and incorporating a cartridge with leaf springs for additional support and adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional tool-based connections are used for assembling chair mechanical subassemblies, then connection strength and reliability are improved, but assembly time and production complexity increase

Engineering Contradiction:
Improveconnection strengthVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces traditional tool-based mechanical connection systems with a tool-free coupling mechanism. The curved member with counter-flange means engages with flange means on the housing portion through a simple coupling movement, eliminating the need for screws, bolts, or other tools while maintaining secure connection. This substitution enables rapid assembly without compromising connection reliability.

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

Solution Approach 2:

The coupling mechanism is designed to be self-securing through the interaction between the curved member and flange means. The geometric arrangement of the counter-flange means and flange means creates an automatic locking effect when coupled, where the components themselves provide the securing function without external tools or additional fastening elements.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If complex preassembly steps are required for chair mechanical subassemblies, then connection precision is improved, but production time and manufacturing complexity increase

Engineering Contradiction:
Improveconnection precisionVSAvoidpreassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The curved member is pre-formed with the counter-flange means integrated into its structure during manufacturing. This preliminary formation of the coupling geometry eliminates the need for complex preassembly steps, as the component arrives at the assembly station ready for direct coupling with the housing portion, maintaining precision while reducing time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The mechanical subassembly is divided into modular components (housing portion with flange means, curved member with counter-flange means) that can be independently manufactured and then quickly assembled. This segmentation allows each component to be optimized separately and assembled through a simple, rapid coupling process without complex preassembly requirements.

Inventive Principle:
Principle #1Segmentation

3Strength

If traditional connection methods are used for curved members, then structural strength is improved, but assembly simplicity and rapidity deteriorate

Engineering Contradiction:
Improvestructural strengthVSAvoidassembly simplicity
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The counter-flange means are integrated directly into the curved member as a single integral component rather than separate parts. This merging of the connection elements with the structural member maintains structural strength while simplifying assembly to a single coupling operation, eliminating the need for separate fastening components or complex assembly procedures.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2983562B8Mechanical subassembly for a chair and chair having such a mechanical subassembly
Publication Date: 2019.01.09 ZWICK GMBH & CO KG

AI summary

The invention relates to a mechanical subassembly (2) for a chair (1), a base element (3), a back element and a seat element (5) being able to be articulated to the mechanical subassembly (2), the mechanical subassembly (2) comprising a housing portion (6) which can be connected to the base element (2) and at least one connection member (V1, V2) which can be connected to the seat element (5) or the back element and the connection member (V1, V2) being pivotably articulated to the housing portion (6).