Convertible Sofa Frame Mechanism for Cushion-Free Bed Conversion

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Solution Overview

Problem

Current convertible armchairs and sofas either lack the ability to provide multiple comfortable resting positions or require removal of cushions and mattresses during conversion, and often necessitate movement away from the wall for configuration changes.

Innovation Solution

A structural framework with interdependent mechanisms that allows for seamless conversion between sofa, armchair, bed, and recliner configurations without removing cushions or mattresses, featuring a base with hinged frames, mechanisms for tilting and synchronizing movements, and optional headrest and footrest adjustments, enabling a single degree of freedom for user-driven configuration changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional convertible sofa mechanisms are used, then the sofa can be converted into a bed, but the cushions must be removed during conversion

Engineering Contradiction:
Improveconversion capabilityVSAvoidcushion handling complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent combines the cushion retention function with the bed conversion mechanism by integrating cushions into the frame structure. The cushions are positioned on the frames in a way that allows them to be automatically stored underneath the bed during conversion, eliminating the need for separate cushion removal and storage operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements nesting by placing the cushions underneath the bed frame during conversion. The cushions are stored in the space created by the folded frame structure, effectively nesting them within the overall bed configuration. This allows the cushions to remain part of the system without interfering with the bed's functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Adaptability or versatility

If conventional convertible sofa mechanisms are used, then the sofa can be converted into a bed, but the furniture must be moved away from the rear wall for conversion

Engineering Contradiction:
Improveconversion capabilityVSAvoidrelocation requirement
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent divides the conversion mechanism into segmented frames that can unfold and extend independently. This segmentation allows the structure to expand horizontally into the room space rather than requiring vertical clearance behind the furniture. The frames are hinged to allow unfolding movements that create the bed configuration while maintaining the rear wall position.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If multiple conversion configurations are added, then the armchair functionality is improved, but the mechanism complexity increases

Engineering Contradiction:
Improveresting position varietyVSAvoidmechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs a universal mechanism that handles multiple configurations (seated position, reclining position, and bed configuration) through a single integrated system. The same frames, hinges, and cushion positioning system that enable bed conversion also facilitate reclining functionality. This multi-functionality is achieved by designing the frame geometry and hinge arrangements to naturally support multiple end positions without requiring separate mechanisms for each configuration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2395879B1Structural framework for convertible armchair or sofa
Publication Date: 2013.09.25 COMODO ITAL SRL
  • EP2395879B1 patent drawingFigure 1
  • EP2395879B1 patent drawingFigure 2
  • EP2395879B1 patent drawingFigure 3

AI summary

A structural framework (1) for a convertible armchair or sofa comprising a box-shaped base (2) supporting a plurality of frames (3, 4, 5, 6) hinged to one another, including a particular frame (6) suitable, alone, for directly or indirectly supporting a seat cushion (19) on one of its sides and, in combination with the other frames (3, 4, 5), for supporting a mattress (18) on its other side, and mechanisms (9,10,11,12, 13) for the displacement of the frames (3, 4, 5, 6) and of a backrest (8) and supporting foot (7) in relation to one another and with respect to the base (2), between: a stable configuration as a sofa or armchair, wherein the frames (3, 4, 5, 6) remain inside the base (2), where they identify a cavity for containing the folded mattress; a stable configuration as a bed wherein the frames (3, 4, 5, 6) extend forwards, becoming aligned to define a horizontal resting surface that extends beyond the base (2) and is supported by the foot (7), while the backrest (8) moves underneath the resting surface; and a stable configuration as a recliner, wherein, by comparison with the configuration as an armchair or sofa, the backrest (8) is tilted further backwards and the particular frame (6) extends further forwards and/or is tilted upwards.