Trim Cover Contact Layer Mitigates Read Through in Vehicular Seats
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Solution Overview
Problem
Conventional dual density or dual firmness vehicular seat elements face challenges in balancing support and comfort, and often result in 'read through' issues when using air permeable trim covers, which is undesirable for automotive applications.
Innovation Solution
A foam article with a textured surface, a trim cover comprising a finished outer layer, a compressible buffer layer, and a contact layer with a secant modulus of at least 7 at 5% strain, which mitigates 'read through' by creating a 'hammock effect' that maintains the trim cover in a taut configuration, preventing the textured surface from being felt or seen through the cover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a textured surface is created in the A-surface of the vehicular seat to provide variable zones of comfort, then comfort is improved, but read through occurs when using air permeable trim covers
Solution Approach 1:
A contact layer with high secant modulus (at least 7 at 5% strain) is introduced as an intermediary between the textured foam surface and the trim cover. This contact layer acts as a mediator that prevents the textured surface from being felt or seen through the air permeable trim cover, while still allowing the textured surface to provide variable zones of comfort. The contact layer's high stiffness prevents excessive deformation that would cause read through.
Solution Approach 2:
The patent changes the mechanical parameter of the contact layer by specifying a minimum secant modulus of 7 at 5% strain. This parameter change ensures the contact layer is sufficiently stiff to prevent read through while maintaining the comfort benefits of the textured surface. The specific modulus requirement transforms the contact layer's mechanical properties to resolve the contradiction.
2Ease of operation
If dual density or dual firmness seat elements are used to provide support and comfort, then comfort is improved, but production cost and complexity increase
Solution Approach 1:
Instead of using multiple foam densities throughout the seat, the patent applies local quality by creating a textured surface on a single density foam base. The texture provides localized variations in firmness and comfort zones only where needed at the contact surface, while the bulk foam remains uniform. This resolves the contradiction by achieving variable comfort without the complexity of multi-density construction.
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
The solution effectively maintains variable zones of comfort in a single density foam while preventing 'read through' in vehicular seats, enhancing fit and finish without requiring significant capital expenditure.
Implementation Method 1
the contact layer having a secant modulus at 5% strain of at least about 7 when measured according to modified ASTM D3574-11, Test E, Tensile Test
Data Source
Figure 1(1)~1(4)
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AI summary
There is described a foam article comprising: a base foam having a textured surface; a trim cover covering at least a portion of the textured surface, the trim cover comprising: (i) a finished outer layer comprising an occupant-contact outer portion and inner portion; (ii) a compressible buffer layer secured with respect to the inner portion of the finished outer layer; and (iii) a contact layer secured with respect to the compressible layer and configured to be in contact with the textured surface of the base foam, the contact layer having a secant modulus at 5% strain of at least about 7 when measured according to modified ASTM D3574-11, Test E, Tensile Test. There is also described a foam article comprising: a base foam having a textured surface; a trim cover comprising a finished outer layer; and optionally, a contact layer interposed between the foam element and the trim cover, the contact layer in contact with at least a portion of the textured surface of the base foam and comprising a contact material; the foam article having a read through score of at least 20 when measured pursuant to modified ASTM D3575-11 I2 (Procedure B). The present inventors have discovered that the occurrence of "read through" may be obviated or mitigated if the contact layer having a secant modulus at 5% strain of at least about 7 when measured according to modified ASTM D3574-11, Test E, Tensile Test is used.