Z-Shaped Chair Frame for Lateral Rocking and Stackability
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Solution Overview
Problem
Cantilever chairs with resilient frames lack lateral movement flexibility and are poorly stackable due to their design, which affects seating comfort and practicality.
Innovation Solution
A Z-shaped frame design with upper, lower, and middle frame parts that allow for lateral movement and improved stackability, featuring a reduced distance between middle frame parts and the upper frame part, enabling rocking in multiple directions and self-centering when stacked.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the frame is designed in a traditional U-shape or Z-shape with equal spacing, then the structure is simple and stable, but lateral movement is restricted and stackability is poor
Solution Approach 1:
The patent applies asymmetry by positioning the middle frame parts at different lateral distances from the upper frame part - specifically, the middle frame parts are positioned closer together laterally than in traditional designs. This asymmetric arrangement enables lateral rocking movement of the seat while maintaining structural stability, resolving the contradiction between movement flexibility and structural simplicity.
2Ease of operation
If the middle frame parts are positioned far apart, then the seat is stable, but lateral rocking movement is restricted
Solution Approach 1:
The patent applies local quality by creating different lateral spacings at different locations of the frame structure. The middle frame parts are positioned closer together in the lateral direction to enable rocking movement, while the overall frame geometry and connections maintain structural stability. This localized adjustment of spacing allows lateral movement without compromising overall frame stability.
3Ease of manufacture
If the frame parts are arranged in a traditional configuration, then manufacturing is simple, but stackability is poor
Solution Approach 1:
The asymmetric positioning of middle frame parts closer together laterally creates a frame geometry that improves stackability. When chairs are stacked, this configuration allows them to nest more efficiently with reduced lateral offset between stacked units, while the manufacturing process remains relatively simple as it involves standard frame construction techniques with adjusted positioning.
Data Source
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AI summary
An item of seating furniture, in particular a chair, is provided, with a frame which is of resilient design and, in side view, is of substantially z-shaped configuration and comprises a frame upper part, two frame lower parts and two frame central parts each connecting a frame lower part to the frame upper part. The frame central parts each run from the respective frame lower part in the rear region of a seat surface obliquely upwards to the frame upper part in the front region of the seat surface. The distance of the frame central parts from each other on the frame upper part corresponds at maximum to half, preferably at maximum to a third, of the width of the seat surface in the front region. This results in the provision of an item of seating furniture which can be stacked particularly readily, permits a great deal of leg room for a person sitting on the item of seating furniture and in which the seat surface can be rocked to the left and to the right.