Deformable Chair Backrest With Localized Rigidity for Low-Cost Comfort
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Solution Overview
Problem
Existing chair designs require high-cost plastic materials with high elastic properties, such as nylon, to ensure proper backrest deformation and comfort, while cheaper alternatives like polypropylene lack sufficient elastic properties for effective operation.
Innovation Solution
Incorporating elastic elements made of spring steel or rigid plastic, integrated into the side uprights of the backrest, to enhance localized rigidity and allow the use of less expensive polypropylene for the backrest, while maintaining the desired deformation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-cost plastic material with high elastic properties (nylon) is used for the backrest, then the backrest provides sufficient elastic thrust and proper deformation characteristics, but the production cost increases
Solution Approach 1:
The patent applies local quality by providing rigidity enhancement only in specific areas where structural support is needed (side uprights and connection elements) rather than making the entire backrest rigid. This allows the use of cheaper polypropylene material while maintaining necessary elastic properties in the resting portion, thus resolving the contradiction between reliability and manufacturing cost.
Solution Approach 2:
The patent employs composite material construction by combining polypropylene (for the resting portion requiring elasticity) with rigidity enhancement elements (in the form of reinforcing structures or different material inserts in the side uprights and connection elements). This composite approach allows each component to have optimized properties for its specific function, achieving both cost reduction and maintained reliability.
2Ease of manufacture
If cheaper plastic material (polypropylene) is used for the backrest, then the production cost decreases, but the elastic properties become insufficient for proper backrest operation
Solution Approach 1:
The patent applies local quality by providing rigidity enhancement only in specific areas where structural support is needed (side uprights and connection elements) rather than making the entire backrest rigid. This allows the use of cheaper polypropylene material while maintaining necessary elastic properties in the resting portion, thus resolving the contradiction between reliability and manufacturing cost.
Solution Approach 2:
The patent employs composite material construction by combining polypropylene (for the resting portion requiring elasticity) with rigidity enhancement elements (in the form of reinforcing structures or different material inserts in the side uprights and connection elements). This composite approach allows each component to have optimized properties for its specific function, achieving both cost reduction and maintained reliability.
3Stability of the object's composition
If the backrest is made entirely rigid, then structural stability improves, but the ability to deform backwards under user thrust is reduced
Solution Approach 1:
The patent applies local quality by creating a differentiated structure where the resting portion remains flexible and deformable while the side uprights and connection elements are reinforced for structural stability. This localized rigidity distribution allows the backrest to maintain overall stability while preserving the necessary deformation capability in the user-contact area.
Solution Approach 2:
The patent segments the backrest into functionally distinct parts: a deformable resting portion for user comfort and adaptive positioning, and rigid side uprights with connection elements for structural support. This segmentation allows each segment to perform its specific function optimally, resolving the contradiction between stability and adaptability.
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
Enables the production of a cost-effective chair with improved comfort and deformation properties using polypropylene, while ensuring the backrest returns to its original position and provides sufficient elastic thrust, overcoming the limitations of prior art chairs.
Implementation Method 1
a deformable resting portion made of plastic material having a non-planar resting surface and provided with at least one weakened area that enables elastic deformation of the resting portion so that the resting portion assumes a configuration bent backwards under the action of a thrust applied backwards by the user
Implementation Method 2
Incorporating elastic elements made of spring steel or rigid plastic, integrated into the side uprights of the backrest, to enhance localized rigidity
Implementation Method 3
The plastic material used for the production of the backrest must moreover ensure that the backrest exerts a sufficient elastic thrust on the back of the user in the deformed position, given that the elastic reaction of the backrest has a marked impact from the standpoint of comfort
Data Source
AI summary
A chair comprising a supporting structure having a seat and a backrest, in which the backrest comprises a deformable resting portion made of plastic material which has a non-planar resting surface provided with at least one weakened area which enables an elastic deformation of the resting portion so that the resting portion assumes a configuration bent backwards under the action of a thrust applied backwards by the user, two uprights formed integrally on the lateral sides of the resting portion, and two side connection elements, which connect the backrest to the supporting structure, formed integrally at the bottom ends of the uprights. The backrest is provided with elastic stiffening elements made of a material different from the material constituting the resting portion and arranged only in an area corresponding to the uprights so as to bestow upon said uprights a rigidity to bending higher than that of the resting portion.