Chair Back Frame Assembly With Pre-Stretched Suspension Fabric
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Solution Overview
Problem
Conventional office chairs face challenges in securely attaching suspension fabric to the back frame, leading to potential instability and discomfort for the user.
Innovation Solution
The office chair features a back frame constructed from two ring-like sections that are ultrasonically welded or fastened together, with the suspension fabric pre-stretched and secured to one section before being attached to the other, creating a secure and ergonomic attachment method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the suspension fabric is attached to the back frame using conventional methods, then the attachment process is simpler, but the fabric attachment stability and tension uniformity deteriorate
Solution Approach 1:
The back frame is divided into two separate ring-like frame sections that are assembled together. The suspension fabric is attached to one frame section independently, allowing for controlled stretching and tensioning before final assembly. This segmentation enables the fabric to be pre-tensioned uniformly across the surface, improving attachment stability while maintaining manageable process complexity through modular assembly steps.
Solution Approach 2:
The suspension fabric is pre-stretched and attached to one frame section before the final assembly with the second frame section. This preliminary action allows the fabric to be tensioned to the desired level and secured in place, ensuring uniform tension distribution and stable attachment before the frame sections are joined together, thereby improving overall attachment reliability.
2Manufacturing precision
If the fabric is stretched and secured to one frame section before assembly, then the fabric tension uniformity improves, but the manufacturing process complexity increases
Solution Approach 1:
By dividing the frame into two separate sections, the fabrication process can independently tension and attach the suspension fabric to one section with precise control. This segmentation allows for uniform fabric tensioning across the entire surface area, achieving high manufacturing precision. The modular nature of the segmented frame reduces the overall complexity by allowing parallel processing of different frame sections.
Solution Approach 2:
The suspension fabric is pre-stretched and secured to one frame section before the final assembly step. This preliminary action ensures that the fabric is tensioned uniformly across the surface, achieving consistent manufacturing precision. By completing the fabric attachment operation before final assembly, the process maintains precision while organizing complexity into manageable sequential steps.
3Reliability
If two ring-like frame sections are used instead of a single frame, then the fabric attachment stability improves, but the frame structure complexity increases
Solution Approach 1:
The back frame is segmented into two separate ring-like frame sections that can be independently manufactured and assembled. This segmentation improves fabric attachment stability by allowing the suspension fabric to be pre-tensioned and secured to one section before final assembly, ensuring stable and uniform attachment. The modular segmented structure manages complexity by allowing independent fabrication and quality control of each section.
Solution Approach 2:
The suspension fabric is pre-stretched and attached to one frame section as a preliminary action before the final assembly with the second frame section. This preliminary attachment ensures stable and uniform fabric tensioning, improving overall attachment reliability. By separating the fabric attachment operation into a preliminary step, the frame structure can achieve stable fabric support while maintaining manageable complexity through sequential assembly operations.
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 provides a stable and comfortable seating experience by ensuring the suspension fabric is tightly fitted and evenly tensioned, enhancing the chair's ergonomic support and durability.
Implementation Method 1
The front and rear ring sections overlie each other in opposing relation and are rigidly secured together by suitable fastening means such as ultrasonic welding
Data Source
AI summary
An office chair is provided having a contoured back assembly comprising a back frame and a suspension fabric. The fabric is attached to the back frame about its periphery wherein the back frame has a three-dimensional contoured shape formed by overlapped frame rings with the fabric being joined thereto. The fabric is secured to the frame by a machine wherein the fabric is first stretched from the outer edge of the fabric and then is clamped by a front frame section in the pre-tensioned or pre-streched condition. The fabric edges are allowed to hang loose and then fixed in the front frame section. Once secured, the fabric is unclamped from the front frame section, and then this sub-assembly is affixed to the rear frame ring to complete the assembly of the back frame.