Chair Frame Foam Molding for Low-Assembly Cushion Integration

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Solution Overview

Problem

Existing chair manufacturing methods are costly and do not effectively integrate comfortable foam cushions with the chair frame, as they require separate assembly and attachment of foam seat and back components to the frame, lacking an efficient method for integrating upholstery during the assembly process.

Innovation Solution

A chair design where the seat and back foam cushions are molded directly onto a partially assembled frame, with the frame pieces being press-fitted together after molding, allowing for the integration of the upholstering process and minimizing post-molding processing, using a two-piece frame structure with one piece having a backrest support and the other a seat support, both with legs, and securing via protrusions and receivers for a secure press fit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If separate assembly of foam cushions and frame is used, then manufacturing flexibility is maintained, but manufacturing cost increases and assembly time is extended

Engineering Contradiction:

Improvemanufacturing costVSAvoidassembly process complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The foam cushion and frame are merged into a single integrated component through injection molding. The foam is molded directly onto the frame structure, eliminating the need for separate assembly steps and reducing manufacturing complexity while maintaining cost-effectiveness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The frame structure is prepared in advance with specific geometric features (protrusions, recesses, channels) that guide the foam injection process. This preliminary preparation enables the foam to be molded directly onto the frame in the correct position, integrating two manufacturing steps into one.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If hard plastic seats are used, then manufacturing cost is reduced, but comfort quality deteriorates

Engineering Contradiction:

Improvemanufacturing costVSAvoidseating comfort

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The seat combines the structural frame material (metal or plastic) with foam material to create a composite structure. The frame provides structural support and cost-effectiveness, while the foam layer provides comfort, achieving both affordability and comfort quality.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If foam cushion is molded separately and then attached, then manufacturing precision is maintained, but assembly time and post-processing increase

Engineering Contradiction:

Improvefoam attachment precisionVSAvoidassembly speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The molding and attachment operations are merged into a single injection molding process. The foam is molded directly onto the frame in one step, eliminating subsequent attachment operations and post-processing while maintaining precise positioning through mold design.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If integrally molded foam cushion is used, then upholstery process is integrated into assembly, but manufacturing process complexity increases

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidmolding process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The frame is pre-designed with integrated geometric features (protrusions, recesses, channels) that serve dual purposes: structural connection and foam molding guides. This preliminary design enables the complex integrated molding process to be executed efficiently without requiring additional complexity during actual manufacturing.

Inventive Principle:

Principle #10Preliminary action

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 method allows for cost-effective manufacturing of chairs with integrated foam cushions, reducing post-processing requirements and enhancing comfort by ensuring the foam is molded directly onto the frame, providing a secure and comfortable seating solution with minimal additional assembly steps.

Implementation Method 1

the backrest support is molded thereover in foam to define a backrest... the seat support is molded thereover in foam to define a seat

Methodology Applied

Scientific EffectInjection molding:

Data Source

PatentUS11457744B2Chair frame with injection molded foam padding

Publication Date: 2022.10.04 SERIES INTERNATIONAL LLC

AI summary

A chair having a first frame portion with a backrest support and a rear leg portion at least part of the backrest support and the leg portion being formed from a single piece. A second frame portion has a seat support and a front leg portion extending in a direction transverse to the seat support, the seat support in a fixed position relative to the backrest support. The backrest support molded thereover in foam, the backrest support being substantially peripherally located around the foam of the backrest and the backrest being provided free from rigid supports extending across a middle portion of the backrest. The seat support molded thereover in foam, the seat support being substantially peripherally located around the foam of the seat and the seat being provided free from rigid supports extending across a middle portion of the seat.