Seat-Bed Folding Frame With Eccentric Seat Support Alignment

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Solution Overview

Problem

Existing seat-bed folding frames face challenges in achieving a compact construction and favorable seat cushion positioning during folding, as the seat support is not optimally aligned in both lying and sitting positions, leading to inefficient space utilization and the need for separate seat cushion adjustments.

Innovation Solution

The seat support is connected to the head-side sub-frame via holding rods and a parallel guide, with an eccentric mechanism that aligns the seat support at the top in the sitting position and under the sub-frame in the lying position, eliminating the need for seat cushion separation, and the backrest support is connected to the support leg, allowing it to adjust according to the desired angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the seat support is connected to the head-side sub-frame via holding rods in a parallel guide with an eccentric mechanism, then the seat support alignment in sitting and lying positions is improved, but the device complexity increases

Engineering Contradiction:
Improveseat support alignmentVSAvoidfolding mechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent employs an eccentric mechanism that changes the positional parameter of the seat support dynamically. The eccentric connection allows the seat support to automatically adjust its position between lying and sitting configurations through rotational movement, achieving proper alignment without complex manual adjustment mechanisms.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The holding rods connected in a parallel guide serve as an intermediary mechanism between the seat support and the head-side sub-frame. This intermediate structure transmits and controls the movement of the seat support, enabling smooth transition and proper positioning while maintaining manageable complexity through a well-defined mechanical path.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If the seat support is positioned at the top of the sub-frame in sitting position and under the sub-frame in lying position, then space utilization is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvespace utilizationVSAvoidseat support positioning precision
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The seat support positioning is made dynamic through the eccentric mechanism and parallel guide system. Rather than requiring fixed precision for both positions simultaneously, the mechanism dynamically transitions the seat support between positions, with precision maintained through the kinematic constraints of the moving components rather than static manufacturing tolerances.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If the backrest support is firmly connected to the support leg to follow its movement, then the backrest angle adjustment is improved, but the structural rigidity decreases

Engineering Contradiction:
Improvebackrest angle adjustmentVSAvoidstructural rigidity
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The backrest support system is segmented into the support leg and the backrest support components. The support leg acts as an articulated element that can pivot to adjust the backrest angle, while the backrest support is firmly connected to follow this movement. This segmentation allows independent optimization of adjustment capability and structural strength in different parts of the mechanism.

Inventive Principle:
Principle #1Segmentation

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

This configuration allows for a more compact folding frame, ensuring the seat cushion is properly positioned in both modes without the need for separation, enhancing space efficiency and user comfort.

Implementation Method 1

The eccentric is controlled by a lever mechanism that transfers the folding movements of the partial frames from the lying position to the sitting position

Methodology Applied
Scientific EffectEccentric mechanism: Eccentric

Data Source

PatentEP1989966B1Seat-bet folding frame
Publication Date: 2009.09.09 SEDAC MECOBEL
  • EP1989966B1 patent drawingFigure 1
  • EP1989966B1 patent drawingFigure 2
  • EP1989966B1 patent drawingFigure 3

AI summary

The frame has a set of partial frameworks (1c-1e) connected by coupling elements e.g. guide lever (12), in such a manner that the frameworks are folded around 90 degrees from a couch position into a seat position. A supporting leg (10) is horizontally folded in the seat position. The seat support is connected with the supporting leg by a set of retaining rods, such that the seat support is controlled by an eccentric. The seat support is rearwardly shifted closely below the framework (1e) in the couch position, and is aligned to the framework (1e) in the seat position.