Structurally improved manual sofa stretching device
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Solution Overview
Problem
Existing manual sofa stretching devices with sliding slot structures are prone to wear, leading to instability and reduced service life when unfolding or folding the leg structure between different posture modes.
Innovation Solution
The use of link rods and linkage rods instead of sliding slots, combined with a limit assembly and springs, allows for smooth unfolding and folding of the leg structure, enhancing stability and service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sliding slot structure is used in the leg structure, then the device can be manufactured at a low cost, but the sliding slot is prone to wear after long-term use, resulting in poor stability
Solution Approach 1:
The patent replaces the sliding slot mechanical structure with a link rod mechanism. Specifically, the leg structure uses multiple link rods (first extension link rod, second extension link rod, third extension link rod, fourth extension link rod) connected through rotatable joints instead of a sliding slot. This substitution eliminates the wear problem inherent in sliding contacts while maintaining the folding and unfolding functionality, thereby improving stability without significantly increasing manufacturing complexity
Solution Approach 2:
The patent employs a dynamic link rod mechanism where multiple rods are rotatably connected to achieve the folding and unfolding motion. The leg structure includes link rods rotatably connected to footrests and mounting side plates, allowing smooth transitions between different posture modes. This dynamic connection system replaces the static sliding slot while maintaining ease of manufacture through simple rotational joints
2Ease of operation
If a sliding slot structure is used, then the initial operation is simple, but the leg structure cannot be unfolded or folded smoothly after long-term use due to wear
Solution Approach 1:
The patent substitutes the sliding slot mechanism with a link rod system featuring rotatable connections. The leg structure utilizes multiple link rods connected through rotational joints that allow smooth folding and unfolding operations. This mechanism eliminates the wear-induced friction problems of sliding slots, ensuring smooth operation throughout the service life while maintaining operational simplicity
Solution Approach 2:
The patent divides the leg structure into multiple segmented link rods (first extension link rod, second extension link rod, third extension link rod, fourth extension link rod) connected through discrete rotatable joints. This segmentation allows each component to move independently and smoothly, preventing the cumulative wear effects that plague monolithic sliding slot structures, thereby extending service life while preserving ease of operation
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 provides improved stability and extended service life by preventing wear and ensuring smooth operation when switching between sitting, TV-watching, and lying posture modes.
Implementation Method 1
One end of the first extension link rod is rotatably connected to the middle of the second footrest. The other end of the first extension link rod is rotatably connected to one end of the fourth foot rod.
Implementation Method 2
A limit assembly is arranged on the base, and is configured to limit the position of the backrest member.
Implementation Method 3
The use of link rods and linkage rods, combined with a limit assembly and springs, allows for smooth unfolding and folding of the leg structure
Data Source
AI summary
A structurally improved manual sofa stretching device includes a base. A functional frame is arranged on the base. The functional frame includes a leg structure, a seat structure and a back structure. The leg structure is connected to the seat structure, and the seat structure is connected to the back structure. The seat structure includes a mounting side plate, and the mounting side plate is arranged on the base. The leg structure includes a third foot rod, a fourth foot rod, a first extension link rod, a second extension link rod, a third extension link rod, a fourth extension link rod, a first Z-shaped linkage rod, a second Z-shaped linkage rod, a first footrest, a second footrest and a small footrest.