Adjustable Bed Push-Pull Actuators and Cam Torque Assist
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Solution Overview
Problem
Existing adjustable beds lack efficient mechanisms for independent height adjustment and articulation, limiting their ability to transition between various positions such as horizontal, Trendelenburg, and reverse-Trendelenburg orientations, and often face mechanical disadvantages during initial raising due to unfavorable angles.
Innovation Solution
The adjustable bed incorporates independent push-pull actuators, torque assist mechanisms with cam surfaces, and articulating frames with pivotable sections, allowing for independent height adjustment and articulation between different positions, and addresses mechanical disadvantages through camming actions and offset pivot axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single actuator mechanism is used for height adjustment, then device complexity is reduced, but the ability to achieve independent height adjustment and articulation between different positions is limited
Solution Approach 1:
The bed system is divided into separate functional modules: height adjustment mechanism with first/second actuators for vertical positioning, and articulation mechanism with third/fourth actuators for angular positioning. This segmentation allows independent control of height and articulation, enabling transitions between horizontal, Trendelenburg, and reverse-Trendelenburg positions without requiring a single complex mechanism.
2Ease of operation
If the bed is raised from a lowered position, then the bed reaches the required operating height, but mechanical disadvantages occur due to unfavorable angles during initial raising
Solution Approach 1:
The system applies preliminary action through torque assist mechanisms that provide enhanced lifting force during the initial raising phase when mechanical disadvantage is greatest. The cam surfaces are positioned to engage at low angles and provide mechanical advantage, assisting the actuators during the most difficult portion of the lifting operation before the bed reaches upright positions where less force is needed.
Solution Approach 2:
Cam surfaces act as intermediary elements between the actuators and the bed frame during the raising operation. These cams translate the actuator's linear motion into rotational motion while providing mechanical advantage through their geometric profile, mediating the force transmission to overcome the unfavorable angles encountered during initial raising.
3Stability of the object's composition
If the bed frame is made rigid for stability, then structural strength is improved, but the ability to articulate between different positions is reduced
Solution Approach 1:
The bed frame is segmented into rigid sections (head section, foot section, side rails) that maintain structural stability, and articulated sections (backrest, leg rest) that can move relative to the rigid portions. This segmentation allows the rigid portions to provide stability while the articulated portions enable positioning adjustments between horizontal, sitting, Trendelenburg, and reverse-Trendelenburg positions.
Solution Approach 2:
The frame combines static rigid elements with dynamic articulated elements. The rigid portions (main frame structure) remain fixed to provide stability, while the articulated portions (backrest, leg rest) are designed to move through controlled ranges of motion. This dynamic configuration allows the frame to maintain stability in its base structure while adapting its shape and orientation to achieve different patient positions.
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
Enables smooth and efficient transition between multiple bed positions, including horizontal, Trendelenburg, and reverse-Trendelenburg orientations, while minimizing mechanical disadvantages during initial raising, enhancing user comfort and operational ease.
Implementation Method 1
The first and second push-pull actuators are configured to exert a pulling force on the upper ends of the leg members of the respective first and second leg assemblies to transition the leg assemblies from a lowered position towards a raised position to raise the fixed frame. The first and second push-pull actuators are configured to exert a pushing force on the upper ends of the leg members of the respective first and second leg assemblies to transition the leg assemblies from the raised position towards the lowered position to lower the fixed frame.
Implementation Method 2
each of the first and second torque assist mechanisms includes a wedge defining a first cam surface configured to interface with a second cam surface defined on the respective one of the first and second leg assemblies to facilitate the initial raising of the fixed frame from the lowered position towards the raised position
Data Source
AI summary
An adjustable bed includes a fixed frame, an articulating frame supported on the fixed frame, first and second leg assemblies, and first and second actuators. The leg assemblies are configured to raise and lower the fixed frame between a lowered position and a raised position. The actuators are disposed and fully maintained within an interior volume of the fixed frame. The first actuator is fixedly secured at a first end to the head end of the fixed frame and operably coupled to the first leg assembly at a second end. The second actuator is fixedly secured at a first end to the foot end of the fixed frame and operably coupled to the second leg assembly at a second end. The first and second actuators are configured to exert a pulling force to raise the fixed frame and to exert a pushing force to lower the fixed frame.