Back support for a chair
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Solution Overview
Problem
Office chairs with rigid peripheral frames and woven mesh backrests often lack torsional flexibility, leading to discomfort and limited adjustability, as the rigidity restricts the mesh's ability to conform to the user's posture.
Innovation Solution
A back support system featuring a flexible frame with independently twisting support arms and a molded suspension mesh, which provides adjustable tension and ergonomic support without the need for a rigid frame, combined with a three-dimensional knit upholstery cover that enhances flexibility and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid peripheral frame is used to support the mesh fabric in tension, then the structural strength and stability are improved, but the torsional flexibility and comfort are worsened
Solution Approach 1:
The rigid peripheral frame is segmented into multiple independent support arms that can twist independently. Each support arm is a separate element that maintains structural integrity while allowing rotational movement, thus providing both strength and torsional flexibility.
Solution Approach 2:
The support arms are designed with dynamic characteristics, allowing them to twist and adapt to user movements. The arms transition from a static rigid structure to a dynamic system that responds to applied forces, enabling the backrest to conform to the user's posture while maintaining support.
2Reliability
If a rigid peripheral frame is used to support the mesh fabric, then the long term comfort and cushioning are maintained, but the range of motion and adjustability are limited
Solution Approach 1:
The frame is divided into multiple support arms that can move independently, allowing the mesh to adjust to various body positions while maintaining the tension and cushioning properties that provide long-term comfort.
Solution Approach 2:
The support arms are designed with specific material properties and geometric parameters that allow controlled twisting motion. By adjusting parameters such as arm thickness, length, and material stiffness, the system maintains comfort characteristics while enabling a wider range of motion.
3Adaptability or versatility
If the support arms are spaced apart to allow independent flexing, then the torsional flexibility is improved, but the structural stability may be worsened
Solution Approach 1:
The frame consists of multiple discrete support arms spaced apart to allow independent movement. Each arm is a separate structural element that contributes to overall stability through its individual strength while enabling torsional flexibility through independent rotation.
Solution Approach 2:
Multiple individual support arms work together as a unified system. The combined effect of several arms, each capable of independent flexing, creates a structure that is both flexible and stable, as the arms collectively distribute and support loads while maintaining structural integrity.
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 system offers enhanced torsional flexibility and ergonomic support, accommodating various user types and postures while maintaining long-term comfort and cushioning, allowing for a wide range of motion and customizable support characteristics.
Implementation Method 1
The support arms are spaced apart from one another such that each of the support arms can be independently flexed at the periphery
Implementation Method 2
The suspension mesh is supported in tension by the flexible portion of the back support frame
Data Source
AI summary
An office-type chair including a back support having a suspension mesh back support and a back support frame. The suspension mesh back support has an integral retaining channel disposed at a peripheral edge thereof, and the back support frame includes a central pair of upright support posts and wedge base for mounting to a chair frame. The back support frame includes a plurality of flexible and spaced support arms extending laterally outward from the upright support posts. The support arms each have a peripheral edge configured for fastenerless attachment in a tensioned state within the suspension mesh retaining channel. An upholstery cover encapsulates the suspension mesh and back support frame. The office chair also includes a lumbar mechanism including a resilient cushion that may be positioned in the space between the suspension mesh and the support frame and adjusted along the vertical extent of the back support by rolling the resilient cushion on the rear of the suspension mesh.