Orthogonal Wheel Alignment in Stretchers for Ambulance Loading
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Solution Overview
Problem
Existing stretchers for transporting patients lack safety and ease of operation, particularly during loading and unloading onto/from ambulances, and do not facilitate single-operator use or adapt to varying transport conditions.
Innovation Solution
A stretcher with independently adjustable front and rear wheels, controlled by a sensor and actuator system to maintain orthogonal wheel alignment, allowing for safe and efficient loading/unloading operations and adaptability to different terrains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual loading/unloading operations are used, then the device complexity is low, but the operational safety and ease of use deteriorate due to heavy physical burden on operators
Solution Approach 1:
The stretcher system performs self-adjustment of wheel inclination angles through sensors detecting leg angular positions and actuators automatically adjusting wheel holders, eliminating the need for manual intervention and reducing operator physical burden while maintaining operational simplicity
Solution Approach 2:
Manual mechanical adjustment of wheel alignment is replaced with an automated sensor-actuator system that electronically controls wheel inclination, substituting human physical effort with automated mechanical systems while keeping the overall device relatively simple
2Adaptability or versatility
If fixed wheel alignment is used, then the device complexity is low, but the adaptability to varying transport conditions deteriorates
Solution Approach 1:
The wheel holder frames are made dynamically adjustable through hinged connections and actuators that allow real-time change of inclination angles, enabling the stretcher to adapt to various terrain conditions while maintaining a relatively simple structural configuration
Solution Approach 2:
The inclination angle parameter of the wheel holders is made variable through automated adjustment mechanisms, allowing the system to adapt to different transport conditions by changing this key geometric parameter without requiring complex structural modifications
3Reliability
If independent wheel adjustment is implemented, then the operational safety improves through maintained orthogonal alignment, but the device complexity increases due to additional actuators and sensors
Solution Approach 1:
Sensors detect the angular positions of stretcher legs and provide feedback to the control system, which then actuates the wheel holders to maintain orthogonal alignment, ensuring operational safety through closed-loop control while keeping the system architecture relatively simple
Solution Approach 2:
The actuator system serves multiple functions by simultaneously adjusting both front and rear wheel holders to maintain orthogonal alignment during loading/unloading operations, reducing the need for separate complex control mechanisms for each wheel
Data Source
AI summary
A stretcher including a support frame for supporting a patient, front legs and rear legs rotatably coupled to the support frame around a respective first and second rotation axis. Each front and rear leg supports respectively a front wheel holder frame hinged to the respective front leg around a first oscillation axis parallel to the first rotation axis and supporting a front wheel resting on a rest plane and a rear wheel holder frame hinged to the respective rear leg around a second oscillation axis parallel to the second rotation axis and supporting a rear wheel resting on a rest plane. The stretcher has a handling arrangement for the front wheel holder frame and the rear wheel holder frame, and a control module configured to keep the first and second pivot axes always orthogonal to the rest plane on which the front and rear wheels roll.