Lumbar and Headrest Adjustment Mechanism With Low-Force Position Control
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Solution Overview
Problem
Existing furniture mechanisms, such as reclining chairs, lack precise control over lumbar support and headrest positions, relying on manual handle operation that does not provide position control for these components, limiting user comfort and convenience.
Innovation Solution
A furniture member adjustment system with mechanisms within upper and lower housing structures, featuring lever arms, biasing members, and cable connections that allow for manual rotation and axial displacement to control the position of lumbar support and headrest components, reducing the force required by the user and enabling greater vertical displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual handle operation is used to adjust the leg rest assembly, then the operation is simple, but position control of lumbar support and head rest members is not provided
Solution Approach 1:
The adjustment system is divided into separate control mechanisms: a release device for the leg rest assembly and a rotary dial for lumbar support and head rest members. This segmentation allows each component to have its own dedicated control method, enabling position control for support members while maintaining simple operation through the release device's automatic return feature.
Solution Approach 2:
The rotary dial mechanism serves multiple functions by controlling both the lumbar support member and head rest member positions. A single control device (the rotary dial) can adjust multiple parameters (lumbar support position and head rest position), reducing the number of controls needed while providing comprehensive position control.
2Ease of operation
If a release device is used to operate the leg rest assembly, then the operation is automatic with return to closed position, but position control of lumbar support and head rest member is not provided
Solution Approach 1:
The system separates the leg rest control (release device with automatic return) from the support member control (rotary dial with position settings). This allows the release device to maintain its automatic return feature while the rotary dial provides position control for lumbar and head rest members.
Solution Approach 2:
The rotary dial acts as an intermediary control mechanism that translates user input into precise positional adjustments for the lumbar support and head rest members. It mediates between the simple automatic release device and the complex positioning requirements of the support members.
3Device complexity
If the lever arm is rotated manually without assistance, then the structure is simple, but the force required by the user is excessive
Solution Approach 1:
The biasing member acts as a mechanical intermediary that stores and releases energy to assist the lever arm rotation. When the lever is rotated, the biasing member compresses or extends, storing energy that then helps return the lever to its initial position, reducing the force the user must apply.
Solution Approach 2:
The biasing member enables the lever arm system to partially service itself by providing the return force needed to reset the mechanism. Instead of requiring the user to manually return the lever to its initial position, the biasing member automatically pushes or pulls it back, reducing user effort.
4Strength
If the cable connection allows limited displacement, then the structural integrity is maintained, but the vertical displacement of lumbar support and head rest is insufficient
Solution Approach 1:
The cable connection is extracted from a rigid fixed-point configuration and replaced with a flexible cable system that can accommodate larger displacements. The cable maintains structural integrity through tension while allowing the lever arm and connected components to achieve greater vertical displacement ranges.
Solution Approach 2:
The cable connection utilizes flexible cable elements instead of rigid connections. This flexibility allows the system to achieve greater vertical displacement while maintaining structural integrity through the cable's tensile strength, accommodating the full range of motion of the lever arm mechanism.
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 precise adjustment of lumbar support and headrest positions, enhancing user comfort by reducing operational force and complexity, while maintaining the structural integrity and aesthetics of the furniture.
Implementation Method 1
A biasing force created by extension of the first or second biasing member operates to bias the first or second lever arm toward the initial position
Data Source
AI summary
A furniture member mechanism includes upper and lower housing structures, the lower housing structure including first and second side frames. A mechanism is disposed within both the upper and lower housing structures, including first and second lever arms having an upper end, a body extending into both the upper and lower housing structures, and a lower end positioned in the lower housing structure and rotatably connected to the first and second side frames. A bracket is connected to the first and second side frames. First and second biasing members are connected to the first and second lever arms and the bracket. The first or second biasing member extends when the first or second lever arm is rotated from an initial position in a lever forward direction. A biasing force of the first or second biasing member biases the first or second lever arm toward the initial position.