Seat Linkage and Backrest Coupling to Prevent Shirt Pull-Off
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Solution Overview
Problem
Existing seats lack optimal adjustability and comfort, particularly in preventing the 'shirt pull-off effect' while allowing for height and inclination adjustments.
Innovation Solution
A seat design featuring a parallelogram linkage mechanism with pivotable and linearly movable rod elements, combined with a weight adjustment device and a trough-like seat plate for enhanced stability and adjustability, prevents the 'shirt pull-off effect and ensures optimal seating comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the seat plate is adjusted in height and inclination using conventional linkage mechanisms, then the seat provides basic adjustability, but the backrest adjustment is limited and the 'shirt pull-off effect' occurs
Solution Approach 1:
The patent combines the seat plate adjustment mechanism and backrest adjustment mechanism into a single integrated linkage system. The coupling linkage connects the seat plate to the backrest, ensuring that when the seat plate is adjusted in height and inclination, the backrest automatically adjusts in coordination. This merging of functions eliminates the need for separate adjustment mechanisms and prevents the 'shirt pull-off effect' by maintaining proper relative positioning between seat and backrest throughout the adjustment range.
Solution Approach 2:
The patent employs dynamic linkage mechanisms that allow continuous adjustment of both seat plate and backrest positions. The coupling linkage enables the system to adapt to different seating positions dynamically, providing optimal support in various postures (driving position, relaxed position, etc.) rather than being limited to fixed adjustment positions.
2Ease of operation
If a complex linkage mechanism is used to achieve simultaneous height and inclination adjustment, then optimal seating comfort is achieved, but the device complexity increases
Solution Approach 1:
The coupling linkage serves multiple functions simultaneously: it connects the seat plate to the backrest, transmits adjustment movements from the seat plate to the backrest, maintains proper geometric relationships between components, and prevents unwanted movements. This multi-functionality reduces the need for additional separate mechanisms, thereby limiting device complexity while achieving comprehensive adjustment capability.
3Adaptability or versatility
If the front connecting levers are made longer than the rear connecting levers, then the seat plate adjusts forwards and upwards with rear part downwards, but the structural design becomes more challenging
Solution Approach 1:
The patent employs asymmetric linkage lever design where the front connecting levers are deliberately made longer than the rear connecting levers. This asymmetric configuration creates the desired adjustment trajectory for the seat plate (forwards and upwards with rear part downwards) while the coupling linkage compensates for the design challenge by coordinating the movement of both levers to achieve smooth, controlled adjustment.
Data Source
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AI summary
A description is given of a seat (10) having a seat panel (12) and a backrest (14). The seat panel (12) is connected to a base device (16) by means of a first connecting device (18). The backrest (14) is connected to the seat panel (12) by means of a second connecting device (20). The first connecting device (18) has a pair of front connecting levers (22) and a pair of rear connecting levers (24). The front connecting levers (22) are longer than the rear connecting levers (24). The rear connecting levers (24) are designed, with an angled extension (34), as a toggle. The second connecting device (20) has a pair of rod elements (36), which are fitted on the seat panel (12), by way of their front end (38), for pivoting and linear movement and which are connected in a pivotable manner to the angled extension (34) of the rear connecting levers (24).