Chair frame with injection molded foam padding
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Solution Overview
Problem
Existing chair designs with injection molded foam do not integrate the foam cushions with the frame, leading to increased manufacturing costs and separate upholstering processes, which can compromise comfort and efficiency.
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-fit together, allowing for integrated upholstering and reduced post-molding processing, utilizing molds that allow frame legs to exit without foam for finishing before molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If injection molded foam is used to create a seat bottom that attaches separately to a chair, then comfort is improved, but manufacturing complexity increases due to separate upholstering processes
Solution Approach 1:
The foam cushion and chair frame are merged into a single integrated structure through injection molding. The foam is molded directly onto the frame, eliminating the need for separate attachment processes and reducing manufacturing complexity while maintaining comfort.
Solution Approach 2:
The frame is prepared in advance with specific features (such as recesses or mounting structures) that enable the foam to be molded directly onto it. This preliminary preparation allows the subsequent molding process to create a permanently attached, integrated seat structure.
2Adaptability or versatility
If foam cushions are molded separately and then attached to the frame, then manufacturing flexibility is maintained, but production time increases
Solution Approach 1:
The foam cushion and frame assembly operations are merged into a single integrated molding process. The foam is injection molded directly onto the frame in one continuous operation, eliminating separate attachment steps and significantly reducing production time.
3Strength
If rigid supports are used across the middle portion of the seat and backrest, then structural strength is improved, but comfort is reduced
Solution Approach 1:
Instead of uniform rigid supports across the entire seat and backrest, the design uses localized foam density variations and strategic frame placement. The foam provides localized support where needed while maintaining overall structural integrity, eliminating uncomfortable rigid bars across the middle portions.
Solution Approach 2:
The seat and backrest use a composite structure combining the frame (for structural strength) with molded foam (for comfort). This composite approach allows the frame to provide necessary strength while the foam eliminates the need for uncomfortable rigid cross-supports.
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 reduces manufacturing costs by integrating the upholstering process and minimizing post-molding processing, while enhancing comfort by ensuring the foam is molded around the frame's support structure, resulting in a cost-effective and comfortable chair design.
Implementation Method 1
the foam is molded around the frame's support structure
Implementation Method 2
those two pieces are press fit together
Data Source
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.