Multi-Joint Chair Central Unit for Single-Material Recyclability
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Solution Overview
Problem
Conventional office chairs have complex structures with numerous components that are difficult to recycle, posing challenges in sustainability and recyclability.
Innovation Solution
A central unit for a chair featuring a multi-joint body made from a single material, utilizing solid-body joints and an injection molding process to simplify design and enable easy recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional mechanical central component made of metal with multiple separate parts is used, then the chair provides structural strength and stability, but the complexity of the structure increases and recyclability deteriorates
Solution Approach 1:
The patent merges multiple separate mechanical components (seat part, backrest part, support part, and joints) into a single integrated multi-joint body made of plastic material. This consolidation eliminates the need for separate metal components and fasteners, directly reducing structural complexity while improving recyclability by creating a single-material construct that can be easily separated and recycled without laborious disassembly.
Solution Approach 2:
The entire multi-joint body is manufactured from a single plastic material, creating a homogeneous structure. This homogeneity simplifies the recycling process significantly, as the entire component can be processed together without needing to separate different materials or types of fasteners, directly addressing the recyclability issue while maintaining structural integrity through the unified design.
2Ease of operation
If multiple separate mechanical components and joints are used, then the chair provides functional movement and stability, but the number of components increases making recycling difficult
Solution Approach 1:
The multi-joint body is segmented into distinct functional regions (seat part, backrest part, support part) connected by integrated joints, allowing independent movement of each section while maintaining a unified single-piece construction. This segmentation provides the necessary functional movement without requiring separate components, thereby reducing the overall number of parts while preserving operational capabilities.
Solution Approach 2:
Multiple joints that would traditionally be separate mechanical components are merged into the single multi-joint body structure. The joints are formed as integral parts of the plastic component rather than separate assemblies, reducing the total component count while maintaining all necessary functional movements for chair operation.
3Adaptability or versatility
If solid-body joints with reduced material thickness are used, then the chair achieves flexibility and elasticity for movement, but the local material strength decreases
Solution Approach 1:
The multi-joint body employs local quality variation by reducing material thickness specifically at the joint regions where flexibility is needed, while maintaining full material thickness in the load-bearing areas (seat part, backrest part, support part). This localized thinning creates the necessary flexibility and elasticity for movement at the joints without compromising the overall structural strength of the chair.
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 solution results in a chair with fewer separate components that can be easily recycled, addressing sustainability concerns while maintaining functional integrity.
Implementation Method 1
A solid-body joint is a region of a component that allows relative movement (rotation) between two rigid body regions by means of bending. A solid-body joint is based on the principle of elasticity.
Implementation Method 2
Such a central unit can preferably be made from a single material, for example in an injection molding process.
Data Source
AI summary
A central unit for a chair, in particular an office chair, has a multi-joint body that is formed of a seat part for a seat, a backrest part for a backrest, a support part for a support of a base and a front part arranged between the seat part and the support part, wherein the multi-joint body comprises at least three joints, which in each case connect two of the specified parts in an articulated manner.