Folding Chair Seat Frame with Surface-Clamped Cushion Support
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Solution Overview
Problem
Conventional folding chair seat frames provide unstable support due to linear contact between the seat cushion and support edges, leading to deformation under load and potential damage.
Innovation Solution
A seat frame design featuring U-shaped and linear support surfaces with L-shaped brackets to securely clamp the seat cushion, ensuring horizontal surface contact and uniform load distribution, preventing deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If linear contact between support edges and seat cushion is used, then the structure is simple, but the support stability is poor and deformation occurs under load
Solution Approach 1:
The patent transitions from linear contact (1D) to surface contact (2D) between the support edges and seat cushion. The support edges are designed with horizontal contact surfaces that provide area contact rather than line contact, fundamentally changing the dimension of contact and thereby improving support stability without excessive complexity.
Solution Approach 2:
The patent changes the contact parameter from line contact to surface contact by designing the support edges with horizontal contact surfaces. This parameter change increases the contact area between the support edges and seat cushion, improving load distribution and support stability while maintaining reasonable structural complexity.
2Strength
If linear contact support edges are used, then manufacturing is simple, but load distribution is uneven causing deformation
Solution Approach 1:
The support edges are designed with horizontal contact surfaces that create 2D surface contact instead of 1D line contact. This dimensional change enables uniform load distribution across the contact surface, preventing deformation while maintaining manufacturing feasibility through simple bending operations.
Solution Approach 2:
The support edges are segmented into multiple functional portions: a horizontal contact surface for load distribution, a vertical portion for structural support, and a curved recess for positioning. This segmentation allows each portion to perform its specific function optimally, achieving good load distribution without excessive manufacturing complexity.
3Reliability
If fastener elements are used to secure the frame and cushion, then the assembly is held together, but the linear contact edges deform under load
Solution Approach 1:
The patent uses surface contact between the horizontal contact surfaces and seat cushion instead of line contact. This dimensional change provides stable support that prevents deformation of the support edges even when fastener elements become loose, thereby maintaining both assembly security and support edge stability.
Solution Approach 2:
The horizontal contact surfaces act as a cushioning mechanism that distributes load before it can concentrate on the fastener elements or cause deformation. This pre-distribution of load protects the support edges from deformation even when the fastening system experiences wear or loosening over time.
Data Source
AI summary
A seat frame for a folding chair includes a U-shaped front frame, a linear rear frame and a seat cushion. The front frame has a first support surface between an upper surface and a lower surface of the front frame, the first support surface having a contour the same as that of the front frame. The rear frame has a second support surface between an upper surface and a lower surface of the rear frame, the second support surface having a contour the same as that of the rear frame. The seat cushion is clamped between the first and second support surfaces in a horizontal position. The peripheral edges of the seat cushion are thereby in tight contact with the first and second support surfaces. Brackets are then used to connect the front frame and the rear frame that surround the seat cushion therein.