Flexible Back Support Notches for Variable Recline Resistance
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Solution Overview
Problem
Existing reclining chairs with complex mechanisms are expensive to manufacture and often have plastic or polymer backs that wear out quickly, are either too stiff or too flimsy, and lack varying reclining resistance.
Innovation Solution
A chair system with a flexible back support member featuring a flex zone with notches that narrow as the back reclines, comprising a beam section and an insert section, where the notches are open in the upright position and closed in the reclined position, providing a customizable reclining resistance through a metal wire and interlocking elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If complex mechanisms are used to accommodate reclining motion, then reclining functionality is achieved, but manufacturing cost increases
Solution Approach 1:
The patent replaces complex mechanical reclining mechanisms with a flexible back support member that uses elastic deformation and geometric design (notches in the flex zone) to provide reclining motion. The flexible member bends and deforms elastically to accommodate reclining angles without requiring joints, hinges, or other mechanical components, thereby eliminating the complexity and cost associated with traditional mechanical systems.
2Ease of manufacture
If plastic or polymer materials are used for reclining backs, then manufacturing cost is reduced, but durability deteriorates due to rapid wear at bending points
Solution Approach 1:
The patent employs a composite structure consisting of a polymer backbone material combined with fiber reinforcement (such as glass fibers or carbon fibers) embedded within the polymer matrix. This composite construction maintains the cost advantages of polymer materials while significantly enhancing durability and wear resistance at bending points. The fibers provide tensile strength and prevent crack propagation, allowing the back support to withstand repeated reclining cycles without deteriorating.
3Strength
If uniform stiffness is maintained throughout reclining, then structural integrity is preserved, but comfort deteriorates due to lack of varying resistance
Solution Approach 1:
The patent incorporates notches of varying depths and positions along the flex zone of the back support member. These notches create localized variations in stiffness: areas with deeper notches provide greater flexibility and lower resistance, while areas with shallower or no notches maintain higher stiffness. This gradient in local properties allows the back support to offer varying resistance throughout the reclining range, enhancing comfort while preserving overall structural integrity through the continuous polymer-fiber composite structure.
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 reduces manufacturing costs, enhances durability, and provides a consistent reclining experience by increasing reclining resistance through a step function as the notches close, optimizing the area moment of inertia and stress distribution.
Implementation Method 1
a minimum area moment of inertia longitudinally along the flex zone in the upright position is smaller than a minimum area moment of inertia longitudinally along the flex zone in the reclined position
Implementation Method 2
The beam section may further include a metal wire extending at least partially along the flex zone, and the metal wire may be, for example, an insert molded steel spring wire
Data Source
AI summary
A chair system according to embodiments of the present invention includes a base comprising a seat for a user and one or more support legs, a back, and a flexible back support element rigidly coupled to the back and to the base, the flexible back support element comprising a flex zone, the flex zone comprising one or more notches, wherein the back is reclinable from an upright position to a reclined position, wherein the one or more notches are configured to narrow as the back reclines from the upright position to the reclined position, and wherein the one or more notches are open in the upright position and closed in the reclined position.