Hospital Bed Positioning Mechanism for Low-Stress Multi-Axis Tilt
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Solution Overview
Problem
Existing hospital bed designs face mechanical stress due to horizontal forces during lateral or longitudinal tilts, require complex electronic installations for height adjustment, and struggle with combining side tilt and Trendelenburg/anti-Trendelenburg positions, leading to structural complexity and high investment costs.
Innovation Solution
A positioning mechanism with three height-adjustable lifters, where the first lifter intersects the patient surface frame's longitudinal axis and is connected swinging and sliding, and the second and third lifters are interconnected with a transverse arm, reducing horizontal load stress and allowing tilting without collision risks, using position sensors for simplified control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lateral or longitudinal tilts are used, then the patient surface can be tilted for therapeutic purposes, but significant mechanical stress is caused to the columns due to horizontal part forces
Solution Approach 1:
The patent introduces an intermediary mechanism - a movable connection point on the patient surface frame that can shift horizontally relative to the column top. This intermediary element mediates between the column and the patient surface, allowing the patient surface to tilt while the column itself remains vertically loaded, thus reducing mechanical stress on the column structure
Solution Approach 2:
The patent adds a horizontal dimension of movement to the traditionally vertical column structure. By allowing the connection point between the column and patient surface to move horizontally, the system transforms the tilt function from a direct horizontal force application on the column to a combined vertical-horizontal movement mechanism, thereby reducing stress on the column
2Reliability
If the bed is raised horizontally before tilting to prevent collision, then collision is avoided, but the electronic installation becomes relatively complicated and absolute position sensing is required
Solution Approach 1:
The patent implements preliminary action by pre-positioning the patient surface frame and undercarriage components such that tilting can occur directly from the lowest horizontal position without requiring prior vertical raising. The movable connection point and articulated arm mechanism are designed in advance to accommodate the full range of tilt motion without collision, eliminating the need for complex collision detection and avoidance control systems
Solution Approach 2:
The patent extracts the collision prevention function from the electronic control system and implements it mechanically through the articulated arm mechanism and movable connection points. The mechanical design inherently prevents collision by allowing the patient surface to tilt about a pivot point that maintains safe clearance, removing the need for electronic sensors and control algorithms to detect and prevent collisions
3Ease of operation
If more than two telescopic extensible lifters are used to control height, then height adjustment capability is improved, but the possibility of mechanism collision in some positions increases
Solution Approach 1:
The patent segments the height adjustment and tilt functions into separate mechanical subsystems. The three lifters are arranged and configured to work in conjunction with the articulated arm mechanism, where each lifter has a defined functional zone. This segmentation allows independent optimization of each component's motion path, reducing the likelihood of collision between mechanisms while maintaining full height adjustment capability
Solution Approach 2:
The patent implements dynamic positioning of the patient surface frame through the combination of three adjustable lifters and the articulated arm mechanism. The system can dynamically adapt its configuration during operation, adjusting the position and orientation of the patient surface to avoid collision zones while achieving the desired height and tilt positions. The movable connection point provides dynamic adjustment of the tilt axis position
4Adaptability or versatility
If complex tilting and positioning mechanisms are used, then positioning capability is improved, but structural complexity and investment demands increase
Solution Approach 1:
The patent achieves multi-functionality by designing the three-lifter system with articulated arms to perform multiple functions: height adjustment, lateral tilt, and longitudinal tilt. The same mechanical components serve all positioning functions simultaneously, eliminating the need for separate mechanisms for each function. The movable connection point and articulated arm structure provide universal capability for various patient surface orientations
Solution Approach 2:
The patent merges the height adjustment mechanism and tilt mechanism into a single integrated system. The three lifters with articulated arms combine the functions of vertical positioning and angular tilting in one mechanism, reducing the overall structural complexity compared to having separate systems. The shared components and coordinated motion control simplify the overall structure while maintaining full positioning capability
Data Source
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AI summary
A positioning mechanism of a bed comprising height adjustable lifters (1, 2, 3) that are mounted on the undercarriage (4) and connected to the patient surface frame (5). The first lifter (1 ) is arranged that its axis intersects the longitudinal axis (6) of the frame (5) and the said lifter (1 ) is connected to frame (5) oscillatingly around the longitudinal axis (6) of the frame (5) and in a sliding way in the direction of the longitudinal axis (6) of the frame (5). The second lifter (2) and the third lifter (2) are interconnected with an arm (10), oriented transversally to the longitudinal axis (6). The arm (10) is oscillatingly connected to the frame (5) and is connected at one end to the second lifter (2) both oscillatingly around an axis, in parallel with the longitudinal axis (6) of the frame (5) and in a sliding way transversally to the frame (5). At the other end the arm (10) is connected to the third lifter (3), oscillatingly around the axis, in parallel with the longitudinal axis (6) of the frame (5).