Sofa Bed Opening Mechanism With Single-Actuator Lever Drive
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Solution Overview
Problem
Existing sofa bed conversion mechanisms require multiple actuators and complex synchronization, leading to economic and reliability issues, as well as aesthetic and safety concerns due to the need for multiple actuators and complex electrical connections.
Innovation Solution
A sofa bed with automatic actuation using a single linear actuator and interconnected levers, allowing conversion from sofa to bed configuration by pushing a button, with the actuator positioned in the fixed framework to simplify the mechanism and reduce stress on components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If multiple actuators are used to actuate the sofa bed mechanism, then the mechanism can be actuated from different points and achieve automatic opening, but the device complexity and economic cost increase
Solution Approach 1:
A single actuator positioned in the base performs multiple functions: it actuates the kinematic chain for configuration conversion, provides opening force, and controls the synchronized movement of all movable frames. This multi-functional actuator replaces what would traditionally require multiple actuators, reducing device complexity while maintaining automatic operation capability
Solution Approach 2:
A transmission mechanism acts as an intermediary between the single actuator and the movable frames. The transmission mechanism distributes the actuator's motion to multiple points in the kinematic chain, enabling coordinated movement of all components without requiring multiple actuators. This intermediary structure allows one actuator to effectively control the entire conversion process
2Extent of automation
If multiple actuators with complex synchronization are used, then automatic actuation is achieved, but reliability decreases due to more components and electrical connections
Solution Approach 1:
The single actuator design eliminates the need for complex synchronization between multiple actuators, reducing the number of potential failure points. By consolidating the actuation function into one reliable component, the system achieves automatic actuation while improving overall reliability through reduced component count and simpler electrical connections
3Adaptability or versatility
If multiple actuators are positioned in the mechanism, then actuation flexibility is improved, but aesthetic appearance deteriorates due to visible actuators and complex connections
Solution Approach 1:
The actuator is extracted from the visible portions of the sofa bed and repositioned in the base, which is not visible when the sofa is in normal use. This extraction maintains the actuation flexibility needed for automatic operation while completely hiding the actuator and its connections, preserving the aesthetic appearance of the furniture piece
4Shape
If the actuator is positioned in the base, then aesthetic appearance and safety are improved, but the force required to move the mechanism increases
Solution Approach 1:
A transmission mechanism serves as an intermediary that amplifies the force generated by the actuator in the base. The transmission mechanism uses mechanical advantage through levers and linkages to convert the actuator's limited force output into the high forces needed to move the mattress and frames, enabling the actuator to be positioned aesthetically in the base while still providing sufficient actuation force
Solution Approach 2:
The transmission mechanism transforms the actuator's linear motion into rotational motion of the movable frames through a series of linkages. This dimensional transformation allows the actuator to apply force at one point while achieving the necessary force multiplication and motion control throughout the entire mechanism
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 enables easy and reliable conversion with reduced force requirements, improved safety, and aesthetic benefits by using a single actuator and minimizing the need for complex electrical connections, while maintaining stability and predictability in the mechanism's movement.
Implementation Method 1
motor means which are associated with said fixed framework and are functionally connected to said at least four movable frames for their movement between said open configuration and said closed configuration, characterized in that said motor means comprise at least one linear actuator
Implementation Method 2
said at least one linear actuator being pivoted to said fixed framework and being functionally associated with said at least four movable frames by a plurality of levers which are interconnected
Implementation Method 3
reduced force requirements
Data Source
AI summary
A sofa bed (1a, 1b) with facilitated opening, particularly with automatic actuation, comprising a fixed framework (2) which defines a compartment (7) for accommodating a mattress (8) that can fold into at least four parts and is supported by at least four movable frames (9, 10, 11, 12), one for each one of the parts of the mattress (8), the first movable frame (9) being associated with the fixed framework (2); the four movable frames (9, 10, 11, 12) are mutually articulated sequentially with respect to each other to define a kinematic chain, with one degree of freedom, which can move between a closed configuration, in which the four movable frames (9, 10, 11, 12) are substantially mutually opposite in pairs so as to define a cage-like structure that encloses the mattress (8) folded into at least four parts, and an open configuration, in which the four movable frames (9, 10, 11, 12) are substantially mutually aligned to define a resting surface on which the unfolded mattress (8) lies; motor means (13) are also provided which are associated with the fixed framework (2) and are functionally connected to the four movable frames (9, 10, 11, 12) for their movement between the open configuration and the closed configuration, the motor means (13) comprising at least one linear actuator (18), which operates along a straight line of action (19) which is substantially parallel to the unfolding direction of the movable frames (9, 10, 11, 12), the linear actuator (18) being pivoted to the fixed frame (2) and being functionally associated with the movable frames (9, 10, 11, 12) by a plurality of levers (24, 26, 29, 32) which are interconnected and are associated with the movable frames (9, 10, 11, 12).