School Bus Seat EPP Cushion Weight Reduction
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Solution Overview
Problem
Existing school bus seat cushions are heavy, difficult to maintain, and require special tooling for replacement, with inconsistent manufacturing leading to time and labor-intensive installation and maintenance processes.
Innovation Solution
The use of an expanded polypropylene (EPP) cushion substrate instead of foam and board configurations, combined with a design that nests inside the frame for increased securement and features an anti-submarine ramp, along with a fastening system that eliminates the need for special tooling for cover material assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If steel latching hardware is used to maintain attachment of the seat cushion assembly to the seat frame, then the attachment strength is improved, but the weight of the seat assembly increases by more than ten pounds
Solution Approach 1:
The patent changes the material parameters from steel to plastic, transforming the latching hardware from a metal-based system to a polymer-based system. This parameter change maintains the functional requirements for attachment strength while dramatically reducing the weight contribution of the latching mechanism, directly resolving the contradiction between strength and weight.
Solution Approach 2:
The patent employs composite material construction by integrating the latching hardware into the plastic seat cushion assembly as a molded-in feature rather than a separate metal component. This creates a composite structure where the plastic material serves both structural and fastening functions, eliminating the need for separate steel latching hardware and reducing overall weight.
2Strength
If foam and plywood board configuration is used for the seat cushion, then the structural stiffness is improved, but the weight of the overall seat assembly increases
Solution Approach 1:
The patent replaces the traditional composite of foam over plywood with an integrated plastic molded cushion assembly. The plastic material provides both the structural stiffness previously achieved through plywood and the cushioning properties, eliminating the need for separate foam and wood layers and significantly reducing weight.
Solution Approach 2:
The patent changes the fundamental material parameter from organic materials (foam, wood, metal) to synthetic polymer material. This parameter change enables a single-material construction that achieves the required structural stiffness without the weight penalty of multiple layered materials.
3Strength
If stapling operation is used to affix cover material to the seat cushion, then the attachment strength is improved, but the time and labor required for installation and maintenance increases
Solution Approach 1:
The patent merges the cover material and latching hardware functions into the molded plastic seat cushion assembly itself. The cover is permanently integrated during molding, eliminating the need for separate stapling operations. This consolidation maintains attachment strength while dramatically reducing installation and maintenance time by eliminating manual fastening steps.
Solution Approach 2:
The patent replaces the mechanical stapling system with a molded-integration system. Instead of using external fastening tools to attach the cover, the design uses the molding process to permanently bond the cover to the cushion structure, eliminating the need for staplers and associated labor.
4Ease of operation
If traditional foam and board cushion design is used, then the comfort is maintained, but the weight reduction goal of forty percent cannot be achieved
Solution Approach 1:
The patent changes the material density and composition parameters by using molded plastic with integrated cushioning features instead of traditional foam. This parameter change achieves weight reduction of at least forty percent while maintaining comfort through the plastic material's inherent cushioning properties and ergonomic design.
Solution Approach 2:
The patent creates a unified plastic composite structure that combines structural support and cushioning functions in a single material system. This composite approach eliminates the weight of separate foam and board layers while maintaining comfort through the plastic material's properties and molded geometry.
Data Source
AI summary
A bus seat for use in a bus comprises a base having a generally rectangular shape when viewed from a bottom. The bus seat further comprises a cushioning material arranged over a top and front portion of the base. The bus seat further comprises a cover material having a fastener with a first end and a second end attached thereto. The first end of the fastener is attached to the cover material while the second end of the fastener is connected to a predetermined portion of the base on a bottom surface thereof.