Sling Bar Integrated Scale with Tilt Compensation
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Solution Overview
Problem
Existing patient lift systems face challenges in accurately measuring patient weight without reducing lift height and require frequent battery replacements or recharging, with in-line scales causing height restrictions and power connectivity issues.
Innovation Solution
Integration of a sling bar with an inductively charged, tilt-compensated load cell within the quick-release link or sling bar, eliminating the need for separate in-line scales and allowing for wireless power recharging without physical connections, ensuring accurate weight measurements even when the sling bar is tilted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an in-line scale is connected between the sling bar and lift strap, then patient weight can be measured, but the lift height is reduced by up to 8 inches
Solution Approach 1:
The scale is integrated directly into the sling bar structure, merging the measurement function with the lifting structure. This eliminates the need for a separate in-line scale connection, thereby preserving full lift height while maintaining weight measurement capability
Solution Approach 2:
The sling bar is designed to serve multiple functions: it acts as both the structural lifting component and the weight measurement device. The load cell is embedded within the sling bar, allowing it to simultaneously support the patient and measure weight without requiring additional components
2Use of energy by moving object
If traditional batteries are used in the scale, then the scale can be powered, but the batteries need frequent replacement and cause operational interruptions
Solution Approach 1:
The scale system automatically recharges its own battery through wireless power transfer when docked at the charging station. The battery management system monitors charge levels and performs recharging without operator intervention, eliminating the need for manual battery replacement and reducing operational interruptions
Solution Approach 2:
The system performs battery recharging in advance during periods when the lift is not in use or when docked at the charging station. This preliminary charging action ensures the battery is ready for the next operational period, preventing power interruptions during patient lifting operations
3Ease of operation
If the sling bar tilts due to unbalanced load, then the load cell measures force at an angle, but weight measurement accuracy deteriorates
Solution Approach 1:
The system continuously monitors the orientation of the sling bar using sensors and provides real-time feedback to the control system. When tilting is detected, the system automatically compensates by adjusting the measurement calculation or activating corrective mechanisms, thereby maintaining accurate weight measurements regardless of sling bar position
Solution Approach 2:
The load cell measurements are dynamically adjusted based on the detected tilt angle. The system changes the measurement parameters by applying trigonometric corrections to account for the angled force vector, converting the inclined force measurement into an accurate vertical weight value
4Duration of action of moving object
If rechargeable batteries are used in the scale, then power can be sustained longer, but the batteries require periodic removal for recharging
Solution Approach 1:
The scale system automatically recharges its own battery through wireless power transfer when docked at the charging station. The battery management system monitors charge levels and performs recharging without operator intervention, eliminating the need to manually remove or handle batteries
Solution Approach 2:
The system replaces mechanical battery removal and insertion operations with wireless electromagnetic power transfer. The inductive charging mechanism allows power to be transferred through air space without physical contact, eliminating the need for battery compartment access and simplifying the recharging process
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
This solution maintains lift height, eliminates the need for battery replacements, and provides accurate weight measurements by compensating for tilts, enhancing operational efficiency and convenience in patient lifting and monitoring.
Implementation Method 1
a secondary inductive charging coil disposed within the cross bar and connected to the terminals of the rechargeable battery, wherein when the secondary inductive charging coil is brought within power transfer range of the primary inductive charging coil, electrical power is supplied by the primary inductive charging coil to the rechargeable battery
Data Source
AI summary
Disclosed is a patient lift system having a sling bar with an inductively charged integrated scale. The lift system comprises a lift apparatus, a lift strap connected at a first end to the lift apparatus, a sling bar connected to a second free hanging end of the lift strap, the sling bar having a scale with a tension load cell integrally disposed therein for measuring forces applied thereto and a power source electrically connected to the scale to provide power to the scale and load cell. An accelerometer is disposed within the sling bar to determine a tilt angle of a lift axis of the load cell relative to a vertical direction of gravitational force. Programming stored in a processor of the integrated scale calculates an accurate weight of an active load suspended from the sling bar, based on the determined tilt angle and the measured force on the load cell.