Lumbar Support Structure for Stable Chair Back Adjustment
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Solution Overview
Problem
Existing lumbar support systems in chairs are inadequate in providing comfortable and stable support, as they often have limited effective support areas, are prone to twisting and wobbling, and fail to move smoothly along curved backrests, leading to uneven contact and insufficient support force.
Innovation Solution
A chair design featuring a lumbar support body that moves vertically along side frame rods with four mounting portions for stable support, a curved lower edge for reduced width from ends to middle, and an operating member connected to the mounting portions for enhanced operation, allowing the lumbar support to be elastically deformed backward and move smoothly along a curved path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the lumbar support body is made wide to support the whole back, then the support area is improved, but the body becomes difficult to elastically deform backward
Solution Approach 1:
The lumbar support body is designed with non-uniform thickness: the central portion has greater thickness to provide elastic deformability and support force, while the lateral portions have reduced thickness. This local variation in structural properties allows the body to be sufficiently compliant for deformation while maintaining adequate support area for contacting the user's back.
2Device complexity
If the lumbar support is supported at two points by handles on the back frame, then the structure is simple, but the support becomes unstable and wobbles when adjusted
Solution Approach 1:
The support structure is divided into multiple independent mounting portions (first mounting portion and second mounting portion) positioned at different vertical locations on the back frame. Each mounting portion independently supports one end of the lumbar support body, creating a multi-point support system that prevents wobbling and improves vertical stability during adjustment.
3Device complexity
If the lumbar support moves vertically along a straight path, then the mechanism is simple, but it cannot follow curved backrests causing uneven contact
Solution Approach 1:
The lumbar support body is designed with inherent elastic deformability, allowing it to dynamically adapt its shape during vertical movement. As the body moves along the curved backrest surface, it elastically deforms to conform to the varying curvature, maintaining uniform contact without requiring a complex curved guidance mechanism.
4Device complexity
If the handles are positioned at the upper end of the lumbar support body, then the structure is compact, but the handles are difficult to operate when the occupant sits on the chair
Solution Approach 1:
The mounting portions are positioned at different vertical dimensions along the back frame, with the first mounting portion located lower than the second mounting portion. This vertical separation allows the lumbar support body to extend downward, placing the handles at a lower, more accessible position for seated users while maintaining a compact overall structure.
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 design provides broader support for the back, stabilizes the lumbar support, and enhances operational capability, ensuring comfortable and uniform support without twisting or wobbling, even when the backrest is curved.
Implementation Method 1
the body is likely to be bent backward and the back can be supported comfortably
Data Source
AI summary
A lumbar support on a chair comprises a lumbar support body in which a vertical width gradually becomes smaller from right and left ends to the middle; four mounting portions spaced apart from each other vertically on the lumbar support body and moving vertically along a guide on each of the pair of side frame rods and an operating member connected to each of the mounting portions on the lower edge.