Variable-Height Siderail Linkage for Safe Bed Access
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Solution Overview
Problem
Hospital siderails face conflicting design requirements between deployed and stored positions, where a siderail tall enough to satisfy deployed state requirements may be too tall for the stored state, and vice versa, while also needing to minimize pinch points and ensure safe occupant access.
Innovation Solution
A siderail design utilizing a four-bar linkage mechanism with outer and inner links that pivot to adjust height, maintaining adequate inter-edge spacing to prevent pinch points and facilitate cleaning, allowing for a larger effective height in the deployed position and a smaller effective height in the stored position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the siderail is made tall to satisfy the deployed state requirements, then the siderail height is sufficient when raised, but the siderail becomes too tall to satisfy the stored state requirements for occupant ingress and egress
Solution Approach 1:
The siderail employs a four-bar linkage mechanism with outer and inner links that enables the siderail to dynamically change its height between a raised deployed position and a lowered stored position. The linkage allows the top of the siderail to be a minimum distance above the deck when deployed, and a minimum distance below the mattress when stowed, resolving the contradiction between needing height for safety and low profile for accessibility.
2Ease of operation
If the siderail is made short to satisfy the stored state requirements, then the siderail allows easy occupant ingress and egress, but the siderail becomes too short to satisfy the deployed state requirements
Solution Approach 1:
The four-bar linkage mechanism enables the siderail to achieve a compact lowered position for easy occupant access while maintaining the capability to extend to a tall deployed position for safety, thus resolving the contradiction between short profile for accessibility and tall height for safety.
3Reliability
If the siderail components are positioned close together to minimize pinch points, then safety is improved, but the mechanism complexity increases
Solution Approach 1:
The siderail divides the linkage mechanism into separate outer link segments and an inner link, with each segment connected at specific joints. This segmentation allows the components to be positioned close together to minimize pinch points while maintaining a manageable and modular mechanism structure that is easier to manufacture and maintain.
Data Source
AI summary
A siderail 52 comprises a rail 70 having a lower edge 72 extending longitudinally from a head end 74 to a foot end 76, and a longitudinally outer link 80 comprising a head side outer link segment 82 and a foot side outer link segment 84. Each segment is connected to the rail at a joint OR and connected to a host frame 28 at a joint OF. The siderail also includes an inner link 110 longitudinally intermediate the outer link segments and connected to the rail at a joint IR and to the host frame at a joint IF. The head side outer link segment extends longitudinally from approximately the head end of the rail lower edge 72 toward the inner link without longitudinally overlapping the inner link. The foot side outer link segment extends longitudinally from approximately the foot end of the rail lower edge 72 toward the inner link without longitudinally overlapping the inner link.