Stair Chair Drive System with Passive Brake
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional powered stair chairs are difficult to control consistently, heavy, and hard to maneuver, making them challenging for caregivers to transport patients safely and efficiently up or down stairs, especially in emergency situations.
Innovation Solution
A patient transport apparatus with a track assembly that deploys and retracts for stair use, featuring a deployment lock mechanism, a folding lock mechanism, and a control system with a motor drive system and passive brake, allowing for controlled movement and stability assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional powered tracks with motors are used to move the stair chair, then the stair chair can traverse stairs, but the device becomes heavy and difficult to maneuver
Solution Approach 1:
The powered track system is divided into separate modules: a drive assembly with motor that can be detached from the stair chair. The track itself is a separate component that interfaces with stairs. This segmentation allows the chair to remain lightweight while the powered track module provides traversal capability when needed.
Solution Approach 2:
A removable powered track assembly acts as an intermediary between the stair chair and the stairs. The track assembly includes a motorized drive system that engages with stair surfaces, allowing the lightweight chair to be propelled without requiring the chair itself to be heavy-duty.
2Speed
If conventional powered tracks with motors are used to move the stair chair, then the stair chair can traverse stairs, but the device becomes difficult to control consistently
Solution Approach 1:
The drive system incorporates sensors that detect stair geometry, surface conditions, and track position in real-time. This feedback is processed by a controller that automatically adjusts motor torque and speed to maintain consistent, predictable operation across varying stair conditions without requiring complex manual control.
Solution Approach 2:
The powered track assembly is designed to self-adjust to different stair configurations through automated sensor-based control. The system independently manages its own operation, selecting appropriate drive modes and parameters based on detected conditions, thereby ensuring consistent control behavior without requiring operator intervention or expertise.
3Adaptability or versatility
If a track assembly is added to enable stair traversal, then the apparatus can transport patients on stairs, but the device complexity increases
Solution Approach 1:
The track assembly is designed as a separate, modular unit that can be attached to and removed from the stair chair independently. This segmentation allows the basic chair structure to remain simple while the powered track module provides additional stair-traversal functionality when needed, reducing overall system complexity.
Solution Approach 2:
The track assembly is designed to be a multi-functional component that can interface with various stair configurations and geometries. By creating a universal track design that adapts to different stair types rather than requiring specialized mechanisms for each scenario, the overall device complexity is reduced while maintaining versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The apparatus enables safe and controlled transport of patients up or down stairs with reduced caregiver effort, improved maneuverability, and enhanced safety features like the passive brake for low battery conditions, ensuring consistent performance.
Implementation Method 1
A patient transport apparatus with a track assembly that deploys and retracts for stair use, featuring a deployment lock mechanism, a folding lock mechanism, and a control system with a motor drive system
Implementation Method 2
control system with a motor drive system and passive brake
Data Source
AI summary
A patient transport apparatus operable by a user for transporting a patient along stairs. A seat section is coupled to a support structure. A track having a belt is attached to the support structure and is arranged for selective operation between: a retracted position, and a deployed position to engage stairs. A drive system with a motor is disposed in rotational communication with the belt to control movement along stairs in the deployed position. A user interface us arranged for engagement to selectively adjust operation of the drive system between: an active state for controlling movement of the belt with the motor, and an inactive state. A braking controller is configured to sense movement of the belt in the inactive state, and to control the motor to limit movement of the belt in the inactive state to effect corresponding limited movement of the patient transport apparatus along stairs.