Motorized Wheel System for Patient Support Apparatus
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Solution Overview
Problem
Existing patient support apparatuses, such as hospital beds and stretchers, with powered transport devices often experience jerky movements due to expensive and difficult-to-use electrical input devices, and lack efficient lateral transport capabilities, complicating user interfaces and control algorithms.
Innovation Solution
A patient support apparatus with a motorized wheel system that includes a wheel support assembly for orientation changes between longitudinal and lateral movement, a user interface with discrete speed settings, and a controller that allows motor operation with the AC power plug plugged into an outlet, ensuring smooth and versatile transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrical input devices (potentiometer or load cell) are used to control motor speed, then infinite speed adjustment is achieved, but the device becomes expensive and difficult to operate consistently
Solution Approach 1:
The patent changes the parameter of speed control from continuous analog adjustment to discrete digital levels. The controller receives signals from the user interface and activates the motor at specific predetermined speeds, eliminating the need for infinite adjustment while improving operational consistency and reducing cost.
2Use of energy by moving object
If the AC power plug is plugged into an electrical outlet, then continuous power supply is available, but the powered transport device is disabled from propelling the patient support apparatus
Solution Approach 1:
The patent introduces dynamic control logic that allows the system to switch between different operational modes based on power source availability. When AC power is detected, the system can still enable powered transport at reduced speeds, providing adaptability while managing power consumption appropriately.
3Adaptability or versatility
If the wheel is re-oriented for lateral transport, then side-to-side movement capability is added, but the user interface and control algorithms become more complex
Solution Approach 1:
The patent segments the transport functions into distinct operational modes (forward/reverse and lateral). The controller receives specific signals from the user interface to activate predetermined speeds in specific directions, simplifying the control logic by avoiding the need for continuous coordinate transformation while still providing versatile transport capability.
Data Source
AI summary
A patient support apparatus includes a frame, a patient support coupled to the frame, a plurality of casters and a wheel coupled to the frame, a motor coupled to the wheel and operable to rotate the wheel to propel the patient support apparatus along a floor, and an electrical system comprising a controller configured to signal operation of the motor to rotate the wheel to propel the patient support apparatus along the floor. The electrical system further includes user inputs adjacent at least one end of the frame and adjacent at least one side of the frame. The user inputs including forward and reverse switches that are engaged to determine whether the patient support apparatus is propelled in a forward direction or a rearward direction, respectively.