Compliant backrest
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Solution Overview
Problem
Conventional backrests in office chairs often fail to provide adequate support and air circulation, with foam limiting air circulation and elastomeric membranes lacking shear resistance, while plastic shells do not conform to the body effectively.
Innovation Solution
A compliant backrest design featuring a flexible shell with longitudinal and lateral slots and a matrix of openings that allows for independent expansion and contraction, providing both macro and micro compliance, and integrated with a peripheral frame for structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If foam materials are used for backrest support surfaces, then support comfort is improved, but air circulation is limited
Solution Approach 1:
The backrest shell incorporates a matrix of openings (porous structure) that allows air to pass through while maintaining the structural integrity and support function of the shell. This resolves the contradiction by providing both comfort support and adequate air circulation.
Solution Approach 2:
The backrest combines a rigid peripheral frame with a flexible shell containing openings, creating a composite structure that provides both structural support and air circulation benefits, eliminating the need to choose between comfort and ventilation.
2Object-affected harmful factors
If elastomeric membranes are used for backrest support surfaces, then air circulation is improved, but shear resistance is insufficient
Solution Approach 1:
The backrest combines a rigid peripheral frame (providing shear resistance) with a flexible shell containing openings (providing air circulation). This composite structure eliminates the need to choose between air circulation and shear resistance.
Solution Approach 2:
The flexible shell with integrated openings provides both the air circulation benefits of membrane structures and the structural integrity needed for shear resistance, eliminating the drawbacks of traditional elastomeric membranes.
3Strength
If plastic shells are used for backrest support surfaces, then structural integrity is improved, but body conforming capability is reduced
Solution Approach 1:
The backrest combines a rigid peripheral frame (providing structural integrity) with a flexible shell (providing body conforming capability). This composite structure allows the shell to deform and conform to the user's body while the frame maintains overall structural strength.
Solution Approach 2:
The flexible shell portion of the backrest can dynamically deform and adapt to the user's body shape during use, while the rigid frame provides stable structural support. This dynamic flexibility resolves the contradiction between structural integrity and body conforming capability.
4Strength
If a rigid peripheral frame is used to bound the backrest, then structural support is improved, but compliance and adaptability are reduced
Solution Approach 1:
The backrest is segmented into a rigid peripheral frame and a flexible shell portion. The frame provides structural support while the shell provides compliance and adaptability, allowing each component to fulfill its specific function without compromising the other.
Solution Approach 2:
The combination of rigid frame and flexible shell creates a composite structure where the rigid portion provides structural support and the flexible portion provides compliance, resolving the contradiction between structural strength 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
The design enhances user comfort by conforming to the body, improving air circulation, and allowing for the integration of auxiliary support members, while maintaining structural integrity and aesthetic appeal.
Implementation Method 1
The shell has a plurality of openings arranged in an area overlying the central opening. The shell has flush front and rear surfaces in the area overlying the central opening. The plurality of openings is configured in one embodiment as a matrix of openings providing independent lateral and longitudinal expansion of the shell relative to the frame.
Implementation Method 2
The openings and slots provide compliance in the backrest, allowing it to move and conform to the user during use, even when bounded by a peripheral frame. At the same time, the openings provide excellent air circulation.
Data Source
AI summary
A backrest includes a frame having a pair of laterally spaced upright members connected with longitudinally spaced upper and lower members. A flexible shell has opposite sides coupled to the upright members and upper and lower portions coupled to the upper and lower members. The shell includes first and second slots extending longitudinally along opposite sides of the shell inboard of locations where the shell is connected to the upright members, and one or more third slots extending laterally along the lower portion of the shell above a location where the shell is connected to the lower member. Terminal ends of the one or more third slots are spaced apart from lower terminal ends of the first and second slots. In other embodiments, the shell is a three-dimensional molded component having a plurality of openings. In various embodiments, the slots and/or openings provide different levels of compliance to the backrest.