Adjustable Chair Toggle Linkage for Differential Seat-Back Pivoting
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Solution Overview
Problem
Existing adjustable chairs lack a mechanism that allows for differential pivoting movement between the backrest and seat, compromising sturdiness and durability while being easy to manufacture.
Innovation Solution
The chair incorporates a toggle arrangement with distinct pivot mechanisms for the backrest and seat, allowing the backrest and seat arms to pivot different degrees, reducing the horizontal and vertical gap between them during tilting, and featuring adjustable pivot points to synchronize their movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a synchronizing mechanism is used to move the seat and backrest simultaneously, then the chair provides better comfort adjustment, but the device complexity increases
Solution Approach 1:
The chair is divided into two independent support mechanisms: a first seat support mechanism connecting the front region of the seat to the base support, and a second seat support mechanism connecting the rear region of the seat to the base support. Each mechanism can be adjusted independently, allowing comfort customization without complex synchronization systems.
Solution Approach 2:
The chair provides dynamic adjustability through multiple pivot points and ranges of motion. The first seat support mechanism allows pivoting about a first horizontal axis, while the second allows pivoting about a second horizontal axis at a different location, enabling flexible positioning adaptations.
2Strength
If the backrest and seat are made sturdy and durable with fixed connections, then the chair structure is stronger, but the adjustability and comfort are reduced
Solution Approach 1:
The chair employs dynamic pivot connections instead of fixed rigid joints. The first seat support mechanism provides pivotal connection at a first pivot point, and the second mechanism provides pivotal connection at a second pivot point, allowing controlled movement while maintaining structural integrity.
Solution Approach 2:
The chair allows parameter changes in position and orientation through adjustable mechanisms. The first seat support mechanism enables adjustment of the front region position, while the second mechanism enables adjustment of the rear region position, both while maintaining structural strength.
3Manufacturing precision
If the pivot points are located closer together to simplify manufacturing, then the manufacturing precision is easier to achieve, but the range of motion and comfort are limited
Solution Approach 1:
The support system is segmented into two distinct mechanisms with pivot points located at different positions. The first pivot point is positioned to allow a first range of motion, while the second pivot point is positioned to allow a second range of motion, collectively providing comprehensive adjustability.
Solution Approach 2:
The chair extends the adjustment capability into multiple dimensional spaces by using two separate pivot mechanisms. The first pivot mechanism operates in one rotational dimension, while the second pivot mechanism operates in another rotational dimension, creating multi-dimensional adjustability.
Data Source
AI summary
An adjustable chair comprises chair support, backrest, a backrest support mechanism including at least one backrest arm pivotally connected to the support, and a seat having front and rear regions and a seat surface. The chair includes first and second seat support mechanisms with the first mechanism adjustably connecting the front region of the seat and the second mechanism adjustably connecting the rear region. The second seat support mechanism includes at least one seat arm having front and rear arm extensions and connected to the support for pivotal movement about a horizontal axis. The rear arm extension is pivotally connected to the rear region of the seat. A toggle arrangement is pivotally mounted on the chair support and engages the front end section of the at least one seat arm and front end section of the at least one backrest arm.