Variable-Height Siderail Linkage for Access and Pinch Safety
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Solution Overview
Problem
Hospital siderails face conflicting design requirements, being either too tall to satisfy the deployed state or too short for the stored state, while also needing to minimize pinch points and ensure adequate gap sizes for safety and access.
Innovation Solution
A siderail design utilizing a four-bar linkage mechanism with outer and inner links that allow for variable height adjustment, maintaining adequate inter-edge spacing to prevent pinch points and facilitate cleaning, and enabling the siderail to meet both deployed and stored position requirements through a larger effective height in the deployed state and a smaller effective height in the stored state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the siderail is made tall to satisfy deployed state requirements, then the siderail height above the deck is sufficient, but the siderail becomes too tall to satisfy stored state requirements for occupant access
Solution Approach 1:
The siderail employs a four-bar linkage mechanism that dynamically adjusts the siderail height between deployed and stored positions. The linkage connects the siderail to the bed frame, enabling automatic height transformation from a tall deployed position (satisfying safety requirements) to a low stored position (facilitating occupant access) through mechanical motion.
2Ease of operation
If the siderail is made short to satisfy stored state requirements, then the siderail allows adequate occupant access, but the siderail becomes too short to satisfy deployed state requirements
Solution Approach 1:
The four-bar linkage mechanism enables the siderail to dynamically transform between short and tall configurations. In the stored position, the linkage positions the siderail low for easy occupant access, while in the deployed position, the same mechanism raises the siderail to the required height for safety compliance.
3Object-affected harmful factors
If the siderail components are positioned close together to minimize pinch points, then safety is improved, but cleaning access becomes more difficult
Solution Approach 1:
The siderail design applies local quality by providing different spacing characteristics in different regions. The inter-edge spacing is minimized at critical pinch point locations to enhance safety, while maintaining adequate spacing in other areas to facilitate cleaning access. This localized approach to spacing optimization resolves the contradiction between safety and maintainability.
Data Source
AI summary
A siderail comprises a rail having a lower edge extending longitudinally from a head end to a foot end, and a longitudinally outer link comprising a head side outer link segment and a foot side outer link segment. Each segment is connected to the rail at a joint OR and connected to a host frame at a joint OF. The siderail also includes an inner link 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 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 toward the inner link without longitudinally overlapping the inner link.