SMA Ejection Mechanism for Test Meters
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Solution Overview
Problem
Conventional test strip ejection mechanisms in medical devices require manual intervention and can lead to contamination and are not suitable for compact, portable test meters, as they involve motors and gears that are bulky and noisy.
Innovation Solution
A test strip ejection mechanism using a shape memory alloy (SMA) strip that transitions from a deformed configuration to a programmed configuration upon heating, exerting a force to automatically eject the test strip without human handling, utilizing a framework, slider, and heating module to achieve smooth and controlled ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional motors and gears are used for test strip ejection, then reliable ejection force can be achieved, but device size increases and noise is generated
Solution Approach 1:
The patent replaces the conventional motor-gear mechanical system with a shape memory alloy-based thermal actuation system. The SMA strip undergoes phase transformation when heated, generating mechanical force directly to eject the test strip, eliminating the need for motors and gears, thereby reducing device size and noise while maintaining ejection functionality.
Solution Approach 2:
The patent utilizes the phase transition of shape memory alloy from martensite to austenite upon heating. This phase transformation generates significant mechanical force that directly propels the test strip ejection, providing reliable ejection force without requiring bulky motor components.
2Device complexity
If manual intervention is used for test strip ejection, then simple mechanism can be used, but contamination risk increases
Solution Approach 1:
The patent implements an automated ejection system where the shape memory alloy strip automatically propels the test strip out of the meter after the measurement is complete. This self-service mechanism eliminates manual intervention in the ejection process, thereby reducing contamination risk while maintaining relatively simple device architecture.
3Extent of automation
If shape memory alloy heating is used for automatic ejection, then automation is achieved and contamination is reduced, but energy consumption increases
Solution Approach 1:
The patent employs periodic heating cycles of the shape memory alloy strip to achieve automatic ejection. The heating is applied only when needed for ejection, rather than continuously, thereby minimizing energy consumption while maintaining automation functionality. The SMA strip is heated, undergoes phase transformation to generate ejection force, and then returns to its original state, creating a periodic action that efficiently achieves automation.
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 SMA-based mechanism operates automatically, reducing human intervention, minimizing contamination risk, and is compact, quiet, and suitable for handheld devices, providing efficient and controlled test strip ejection without the need for motors or gears.
Implementation Method 1
The SMA strip has first and second ends that are attached to the framework and exhibits a solid state transition temperature. The SMA strip and slider are configured such that the slider travels along the framework under an applied force exerted on the slider by the SMA strip as the SMA strip is heated from a temperature below the solid state transition temperature to a temperature above the solid state transition temperature.
Implementation Method 2
The heating module is configured to heat the SMA strip from a temperature below the solid state transition temperature to a temperature above the solid state transition temperature.
Data Source
Figure 1
Figure 2A~2B
Figure 2C~6
AI summary
A test strip ejection mechanism, for use with a test strip receiving port and a test strip, includes a framework, an elongated shape memory alloy (SMA) strip (e.g., a SMA wire), a slider, and a heating module. The SMA strip has first and second ends that are attached to the framework and exhibits a solid state transition temperature. The slider is configured to travel along the framework. The heating module is configured to heat the SMA strip from a temperature below the solid state transition temperature to a temperature above the solid state transition temperature. Moreover, the SMA strip and slider are configured such that the slider travels along the framework under an applied force exerted on the slider by the SMA strip as the shape memory strip is heated from a temperature below the solid state transition temperature to a temperature above the solid state temperature by the heating module. In addition, the slider has a proximal end configured to engage a test strip received within a test strip receiving port and eject the test strip from the test strip receiving port as the slider travels along the framework. A test meter for use with a test strip includes a test strip receiving port and a test strip ejection mechanism.