Mechanical stretching device for movable seat unit and seat unit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing movable chair units experience a gap between the backrest and the seat when switched to the lying position, leading to discomfort and the risk of items falling.
Innovation Solution
A mechanical stretching device for a movable seat unit, comprising a seat assembly, a backrest assembly, and a leg stretching device, which allows the seat unit to be switched between sitting, TV, and lying positions while eliminating the gap between the backrest and the seat through a scissor structure in the backrest link assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the seat unit is switched to the lying position, then the user experiences zero gravity feeling with legs higher than head, but a gap occurs between the backrest and the seat causing discomfort and item falling risk
Solution Approach 1:
The backrest assembly is divided into multiple segments: the backrest itself, the backrest connecting member, and the backrest link assembly with first and second backrest links. This segmentation allows each component to move independently, enabling the backrest to maintain continuous contact with the seat while achieving the lying position with legs higher than head.
Solution Approach 2:
The backrest link assembly employs a dynamic linkage mechanism where the first backrest link is hinged to the central driven member and the second backrest link is hinged to the lateral plate, with the first backrest link connected to the second backrest link. This dynamic structure adapts during position transitions, ensuring continuous contact between the backrest and seat while achieving the desired lying position.
2Ease of operation
If the backrest is reclined significantly in the lying position, then ergonomics are improved, but a gap forms between the backrest and seat
Solution Approach 1:
The backrest link assembly acts as an intermediary mechanism between the central driven member and the backrest. It includes a first backrest link hinged to the central driven member and a second backrest link hinged to the lateral plate, with the first backrest link connected to the second backrest link. This intermediary linkage maintains continuous contact between the backrest and seat while enabling significant recline angles for improved ergonomics.
3Ease of operation
If the footrest extends forward and upward in the lying position, then zero gravity feeling is enhanced, but the structure becomes more complex
Solution Approach 1:
The leg stretching device merges multiple functions into a single integrated mechanism. It includes a plurality of links pivotally connected with each other and a first footrest member attached to the footrest, all connected to the lateral plate. This unified structure achieves the footrest extension forward and upward for zero gravity feeling while managing structural complexity through functional integration.
Data Source
AI summary
The present disclosure relates to a mechanical stretching device for a movable seat unit, including: a seat assembly, including a base assembly, a lateral plate, and a central driven member; a backrest assembly, pivotally connected to a rear part of the lateral plate; a leg stretching device, pivotally connected to a front part of the lateral plate, including a first footrest member; the mechanical stretching device allows the seat unit to be switched between a sitting position and a lying position; the first footrest member is folded below a seat when in the sitting position; and the backrest is relined backward, a highest point of the footrest is higher than a highest point of the backrest, and the first footrest member is stretched forward and upward, when in the lying position. The present disclosure further relates to a movable seat unit.