Stackable chair
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Solution Overview
Problem
Existing stackable chairs face issues with stability and damage during stacking and unstacking, particularly when made of metal with surface coatings, and their design complexity and aesthetic appeal are suboptimal.
Innovation Solution
The chair design features bow-shaped cross struts that act as both stacking aids and support bars, integrating them into the armrests which merge into downward-pointing support bars, allowing for easy and stable stacking while minimizing contact between chair frames to prevent damage, and allowing for easy production and visually appealing appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If chairs are stacked one on top of the other using conventional armrest and leg contact, then stacking is simple, but the stack is unstable and surface damage occurs easily
Solution Approach 1:
The patent introduces cross struts as intermediary elements between the armrests and chair legs. These cross struts act as mediators that distribute the stacking load across multiple contact points rather than concentrating force on the armrest and leg surfaces. The cross struts create additional support planes that enhance stacking stability while preventing direct contact between the vulnerable armrest and leg surfaces.
2Ease of operation
If metal chairs with surface coating are stacked conventionally, then stacking is straightforward, but surface damage occurs easily during stacking and unstacking
Solution Approach 1:
The cross struts are designed to engage before the armrests and legs make direct contact during the stacking process. By providing initial contact points through the cross struts, the design cushions the impact and distributes forces gradually, preventing sudden shocks that would damage the surface coating on metal chair components.
3Reliability
If special functional strips are added for stacking support, then stacking stability improves, but production complexity increases and aesthetic appeal decreases
Solution Approach 1:
The patent merges the cross struts with the existing armrest structure, creating an integrated design where the cross struts are formed as continuous elements from the same metal tubing as the armrests. This integration eliminates the need for separate functional strips or additional components, simplifying production while maintaining stacking stability. The unified structure also improves aesthetic appeal by creating clean, consistent lines throughout the chair frame.
4Shape
If bow-shaped cross braces are used as stacking aids, then stacking stability improves and appearance enhances, but the design complexity increases
Solution Approach 1:
The cross struts are designed with a bow shape featuring curved arc sections that provide both aesthetic appeal and functional benefits. The curvature allows the cross struts to flex slightly under load, enhancing stability, while also creating an attractive visual element. The bow shape is achieved through standard metal tube bending processes, keeping manufacturing complexity manageable despite the curved geometry.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a stackable chair with a chair frame, a seat (6) attached thereto and a backrest (7), wherein the chair frame has on both sides of the chair (1) a side part (2,3) suitable for stacking two chairs on top of each other, wherein each side part (2,3) has a front and a rear chair leg (8,10,9,11), wherein a crossbar (20,21) is arranged on each side part (2,3) as a stacking aid. It is provided that the respective crossbar (20,21) is designed in a bow shape with a central, straight bow section (20a,21a) and an arc-shaped bow section (20b,20c,21b,21c) at each end of the central bow section (20a,21a) and is directed outwards in such a way that when stacked on top of each other, the two bow-shaped crossbars (20,21) of the upper chair (1A) enclose the two side parts (2,3) of the lower chair (1B).