Platform Load Cells for Patient Bed Weight Measurement
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Solution Overview
Problem
Existing reclining devices, such as beds and couches, face high production costs due to complex sensor units used for weight measurement, which are not cost-effective or structurally simple.
Innovation Solution
The use of platform load cells, specifically designed as double bending beams, between the underframe and frame, with a floating bearing for mounting, allows for precise and cost-effective weight measurements, enabling reliable weight determination and compensation for eccentric loads, and wireless data transmission for monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex sensor units with strain sensors in cylindrical protective containers are used, then weight measurement capability is achieved, but production costs and device complexity increase significantly
Solution Approach 1:
The patent extracts the weight measurement function from the complex sensor unit and relocates it to a simple platform load cell positioned at the interface between frame and base. This separates the measurement function from the structural components, allowing the use of inexpensive load cells instead of complex strain sensor assemblies.
Solution Approach 2:
The patent replaces expensive, complex sensor units with inexpensive platform load cells that are standard, readily available components. These load cells provide sufficient measurement precision for weight detection while being significantly cheaper and simpler to manufacture and replace.
2Measurement precision
If special complex sensor units are used for weight determination, then measurement function is achieved, but manufacturing costs increase
Solution Approach 1:
The patent employs inexpensive platform load cells that are standard industrial components, replacing custom-designed complex sensor units. These load cells are significantly cheaper to manufacture while providing adequate measurement precision for patient weight determination.
Solution Approach 2:
The platform load cells serve multiple functions: they provide weight measurement, support the frame structure, and can accommodate eccentric loads. This multi-functionality eliminates the need for separate specialized sensors, reducing overall manufacturing complexity and cost.
3Device complexity
If platform load cells are used between underframe and frame, then measurement simplicity and cost-effectiveness are achieved, but measurement accuracy must be maintained under varying conditions
Solution Approach 1:
The patent compensates for parameter changes by using platform load cells that are inherently designed to handle varying load conditions. The load cells are positioned to measure forces in the vertical direction, and the system accounts for changes in measurement conditions through the design of the load cell placement and the platform structure.
Solution Approach 2:
The platform load cells are designed with inherent compensation capabilities that pre-account for potential measurement errors due to eccentric loads and position variations. The platform structure itself provides stability and distributes loads in a controlled manner, ensuring accurate measurements under varying patient positions.
4Adaptability or versatility
If the frame is movably mounted with a bearing in the longitudinal direction, then adaptability to different positions is achieved, but measurement stability may be affected
Solution Approach 1:
The patent segments the movement function from the measurement function by placing the movable bearing in the longitudinal direction (separate from the weight measurement plane) and using platform load cells that are insensitive to longitudinal movements. This segmentation allows the frame to move freely in the longitudinal direction while maintaining stable weight measurements in the vertical direction.
Solution Approach 2:
The platform load cells are specifically positioned and oriented to measure only the vertical component of force, making them locally sensitive to weight changes while being insensitive to longitudinal movements. This local quality of the measurement system allows the frame to be movably mounted without affecting measurement stability.
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 configuration provides accurate, reliable, and cost-effective weight measurements, allowing for precise monitoring of a person's position and weight, with the ability to detect changes in weight distribution and trigger alarms, enhancing patient safety and reducing operational complexity.
Implementation Method 1
Sensor units with force sensors are arranged between the frame and the base. The weight of a person located on the lying device can be determined with the sensor units.
Implementation Method 2
Such platform load cells are extremely robust and versatile and particularly suitable for absorbing eccentric loads. Shifts in the point of force application are compensated by platform load cells, so that very precise measurements are possible.
Implementation Method 3
the frame is mounted at another end and/or on another cross member by means of a bearing - preferably a floating bearing - in the longitudinal direction is movably mounted
Data Source
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AI summary
With regard to a reliable weight measurement, which can be realized with structurally simple and relatively inexpensive means, a couch device, especially a bed or couch, with a base frame (1) and a frame (2), which is disposed on the base frame (1), is equipped and developed in such a manner, that at least two platform weighing cells are disposed between the base frame (1) and the frame (2).