Variable-Height Siderail Linkage for Pinch-Safe Bed Access
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Solution Overview
Problem
Hospital siderails face conflicting design requirements, being too tall to satisfy the stored state or too short to meet the deployed state, and must minimize 'pinch points' that change size with position.
Innovation Solution
A siderail design using a four-bar linkage mechanism with outer and inner links that pivot to adjust height, maintaining adequate inter-edge spacing to address height requirements and prevent pinch points, allowing for both deployed and stored positions while ensuring occupant safety and access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the siderail is made tall to meet the deployed state requirements, then the siderail height above the deck is sufficient, but the siderail becomes too tall for the stored state requirements
Solution Approach 1:
The patent applies a four-bar linkage mechanism that enables the siderail to dynamically change its height between deployed and stored states. The linkage consists of interconnected bars (siderail bar, deck bar, foot bar, head bar) that pivot relative to each other, allowing the siderail to transition from a tall configuration during deployment to a shorter configuration during storage, thus adapting to different operational requirements
2Length of moving object
If the siderail is made short to meet the stored state requirements, then the siderail clearance from the floor is sufficient, but the siderail becomes too short to meet the deployed state requirements
Solution Approach 1:
The four-bar linkage mechanism dynamically adjusts the siderail height based on operational state. When deployed, the linkage configuration provides maximum height for safety and support. When stored, the same mechanism reduces the height to provide adequate clearance from the floor, thus maintaining reliability across different states without requiring multiple siderail configurations
3Object-affected harmful factors
If the siderail links are positioned close together to reduce pinch points, then safety is improved, but the mechanism complexity increases
Solution Approach 1:
The patent divides the linkage mechanism into distinct segmented bars (siderail bar, deck bar, foot bar, head bar) connected by pivots. This segmentation allows each component to be independently positioned and sized, enabling the design to minimize pinch points at the interfaces between segments while maintaining overall mechanism simplicity through standardized connection methods
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.