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Solution Overview
Problem
Existing chair designs with a rocking function either lack simplicity, versatility, or comfort due to constraints in backrest tilting angle and rigidity, and often result in the backrest swinging easily or not swinging enough, limiting user comfort and causing disturbances when seated.
Innovation Solution
A chair design featuring a backrest connected to an upper support frame with a T-shape or L-shape side support bodies, where the backrest is attached at a position lower than the upper-lower intermediate position, providing increased resistance to backward tilting and allowing for a larger rocking angle without excessive thickness, and incorporating a gas cylinder leg device for adjustability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the backrest is connected to the upper support frame with a simple structure, then the chair has versatility and simplicity, but the backrest tilting angle is constrained and rocking function is limited
Solution Approach 1:
The upper support frame is divided into multiple segments (left side portion, right side portion, rear portion) that can move independently. The backrest is separated from the seat, and the upper support frame is positioned between them, allowing independent movement of each component to achieve both simplicity and large tilting angle.
Solution Approach 2:
The rocking mechanism transitions from a single-plane rotation to a two-stage compound motion involving both lateral tilting (upper support frame relative to side support bodies) and backward tilting (backrest relative to upper support frame), effectively increasing the total rocking angle without proportionally increasing structural thickness.
2Stability of the object's composition
If the upper support frame is made thicker to increase rigidity, then the rocking stability improves, but the chair structure becomes excessively thick and less versatile
Solution Approach 1:
The upper support frame is segmented into left side portion, right side portion, and rear portion connected by thin walls. This segmentation allows each part to move independently for rocking while maintaining overall structural integrity, achieving stability without excessive thickness.
Solution Approach 2:
The upper support frame combines metal materials with high strength-to-weight ratio to achieve sufficient rigidity and rocking stability with reduced thickness, avoiding the need for overly thick structures while maintaining performance.
3Ease of operation
If the backrest is connected at the upper-lower intermediate position, then the structure is balanced, but the rocking angle is limited and comfort is reduced
Solution Approach 1:
Instead of connecting the backrest at the conventional upper-lower intermediate position, the patent connects it at the lower than intermediate position (lower third region). This inverted connection position allows the backrest to tilt backward more freely while the upper support frame provides the rocking motion, enhancing both comfort and tilting angle.
4Ease of operation
If the backrest tilts backward easily, then user comfort improves, but the backrest swings excessively and disturbs others seated nearby
Solution Approach 1:
The rocking motion is segmented into two independent stages: lateral tilting of the upper support frame and backward tilting of the backrest. This segmentation allows controlled backward tilting for comfort while the lateral tilting component prevents excessive swinging that would disturb others.
Solution Approach 2:
The patent changes the resistance parameters differently for the two rocking stages: lower resistance for backrest backward tilting (enhancing comfort) and higher resistance for upper support frame lateral tilting (preventing excessive swinging and disturbance to others).
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 enhances comfort by allowing a greater backrest tilting angle without disturbing others, prevents the 'shirt rolling' phenomenon, and maintains a stable rocking posture, ensuring user comfort and ease of use.
Implementation Method 1
a spring which gives resistance to backward tilting of the backrest is arranged inside the back strut
Data Source
Figure 1(A)~1(D)
Figure 2(A)~2(C)
Figure 3(A)~3(B)
AI summary
A chair includes, a seat, a backrest separated from the seat, and an upper support frame to which the backrest is attached at a position higher than the seat. In the chair, the upper support frame includes a left side portin and a right side portions both extending forward at left and right sides of the seated person and a rear portion that continuously and integrally connects the left side portion and the right side portion. The left side portion and the right side portion are connected to side support bodies arranged on left and right sides of the seat to be tiltable, and the backrest is connected to the upper support frame to be tiltable rearward.