Infusion Pump Drive System Axial Positioning
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Solution Overview
Problem
Infusion pump systems are prone to inadvertently dispensing medicine due to impacts or pressure changes, which can lead to inaccurate dosing and safety issues.
Innovation Solution
The infusion pump system incorporates a drive system with a spring-biased piston rod and drive wheel configuration that remains anchored during impacts, preventing axial shifts and ensuring controlled dispensation of medicine. This includes an electrically powered actuator, a ratchet mechanism, and a movable pawl system to advance the piston rod incrementally, while the drive wheel is biased to maintain a consistent axial position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the drive wheel and piston rod are freely movable to enable flexible operation, then ease of operation is improved, but reliability deteriorates due to inadvertent dispensing during impacts
Solution Approach 1:
The spring mechanism applies a preliminary counteracting force to the drive wheel, creating a bias that opposes unintended axial movement during impacts. This preliminary anti-action prevents the piston rod from shifting and dispensing medicine inadvertently, while allowing controlled movement during normal operation when the spring force is overcome by the actuator.
2Reliability
If the drive system components are rigidly fixed to prevent movement during impacts, then reliability is improved, but ease of operation deteriorates due to reduced flexibility
Solution Approach 1:
The drive wheel is designed with dynamic characteristics, being spring-biased rather than rigidly fixed. This allows the system to adapt between two states: remaining stationary during impacts (when spring force maintains position) and moving freely during controlled operation (when actuator overcomes spring force). The dynamic spring mechanism resolves the contradiction between rigidity for reliability and flexibility for ease of operation.
3Reliability
If the piston rod is spring-biased to prevent axial shifts during impacts, then reliability is improved, but device complexity increases due to additional spring mechanism
Solution Approach 1:
The spring mechanism serves multiple functions simultaneously: it biases the drive wheel to prevent inadvertent movement during impacts, provides a restoring force for the ratchet mechanism operation, and enables controlled dispensing when activated by the actuator. By making the spring mechanism multi-functional, the patent reduces overall device complexity compared to using separate components for each function.
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 solution effectively reduces the likelihood of medicine being inadvertently dispensed due to impacts, allowing for accurate and controlled dosing of medicine, enhancing user safety and system reliability.
Implementation Method 1
the drive wheel may be spring-biased in an axial direction that is generally opposite to the longitudinally forward direction so that the drive wheel is urged toward a selected axial position in the pump housing
Data Source
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AI summary
Some embodiments of an infusion pump system include a drive system that advances a piston rod to dispense medicine to a user. Moreover, the drive system can be configured to reliably dose selected amounts of medicine to the user while also reducing the likelihood of inadvertent dispensing of medicine in response to impacts or pressure changes exerted upon the infusion pump system.