Convertible Sofa Bed Linkage for Floor-Safe Cushion Folding
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Solution Overview
Problem
Conventional convertible seating furniture with a bed function often requires rollers that can damage the floor and necessitates space for an upright additional cushion, failing to efficiently cover all cushions with a bed covering.
Innovation Solution
The seat cushion is mounted via a parallelogram linkage, allowing the additional cushion to fold under the seat cushion in the sitting position, with a self-roller accommodating a bed covering that can cover all three cushions, and the self-scooter is designed for easy removal and replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rollers are used to support the seat cushion and additional cushion, then the furniture can be easily moved and transformed, but the rollers may damage the floor
Solution Approach 1:
The harmful rollers are completely removed from the furniture design. Instead of using rollers to support and move the cushions, the patent employs a mechanical linkage system with arms and pivots that enable transformation without contact with the floor, thereby eliminating floor damage while maintaining ease of operation
Solution Approach 2:
A parallelogram linkage mechanism with arms and pivots is introduced as an intermediary system. This mechanism mediates between the need for movement/transformability and the need to protect the floor, allowing the furniture to be reconfigured without direct floor contact from rollers
2Ease of operation
If the additional cushion is arranged upright on the rear side, then it is easily accessible, but it requires space at the rear of the furniture
Solution Approach 1:
The additional cushion transitions from a static upright position to a dynamic position that changes with the furniture configuration. Through the linkage mechanism, the additional cushion automatically moves to an accessible position during transformation while occupying minimal rear space in the sitting configuration
Solution Approach 2:
The additional cushion is positioned within the space defined by the seat cushion and backrest structure. When the furniture is in sitting position, the additional cushion nestles into the available space without protruding significantly rearward, and becomes accessible during transformation sequences
3Ease of operation
If the bed covering is rolled on a self-roller, then it can be easily stored and deployed, but it can only cover two cushions leaving the third uncovered
Solution Approach 1:
The bed covering on the self-roller is designed with extended length and adjusted dimensions to serve multiple functions: it can now cover all three cushions (seat cushion, backrest, and additional cushion) rather than just two. This universal covering solution maintains ease of storage and deployment while adapting to the complete furniture set
Solution Approach 2:
The dimensions and length of the bed covering are modified to match the new furniture configuration with three cushions. By changing the parameter of covering length, the system achieves comprehensive coverage of all cushions while retaining the beneficial self-roller storage and deployment mechanism
Data Source
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AI summary
In a piece of seating furniture that can be converted into a bed, the backrest (3) of which can be pivoted into the plane of the seat surface of a seat cushion (2) by means of arms (12) pivotally mounted on it, an additional cushion (4) is provided, which is connected to the seat cushion ( 2) and the backrest (3) forms a lying surface. The seat cushion (2) is mounted in the furniture frame (1) by means of parallelogram links (6, 6') and the additional cushion (4) can be moved from the lying position to a position below the seat cushion (2) located in the sitting position. This results in a simple and practical arrangement.