Injection Device Plunger Speed Control via Sensor Feedback
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Solution Overview
Problem
Existing injection devices often unintentionally discharge substances from syringes or cartridges due to inability to reduce plunger speed effectively, leading to potential harm or loss of valuable substances.
Innovation Solution
Incorporation of a sensor device with a sensor element, such as a microswitch, that detects the position of the plunger relative to the holder, allowing for controlled reduction or cessation of plunger speed upon contact with the stopper, preventing unintentional displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the plunger is moved with high speed to reach the stopper quickly, then productivity is improved, but the stopper may be unintentionally discharged causing harm or loss of substance
Solution Approach 1:
The sensor device detects the stopper's position in advance before the plunger reaches it, triggering a speed reduction action beforehand. This preliminary detection and response prevents the harmful effect of unintentional discharge while maintaining high overall productivity.
Solution Approach 2:
The sensor device provides real-time feedback on the stopper's position to the control device, which adjusts the plunger speed accordingly. This feedback mechanism ensures that high speed is maintained until the critical moment, then immediately reduced to prevent substance discharge.
2Object-affected harmful factors
If the plunger speed is reduced to prevent unintentional discharge, then safety is improved, but the time required for injection increases
Solution Approach 1:
The plunger operates at high speed during the majority of the injection process, then periodically reduces speed only when the sensor detects the stopper's position. This periodic speed adjustment maintains overall efficiency while preventing unintentional discharge at the critical moment.
Solution Approach 2:
The sensor device triggers speed reduction in advance when the stopper is detected, allowing the plunger to maintain high speed for as long as possible. This preliminary action minimizes the time spent at reduced speed while ensuring safety.
3Measurement precision
If a sensor device is added to detect plunger position, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent employs a sensor device that likely uses optical, magnetic, or capacitive fields rather than complex mechanical linkages to detect plunger position. This substitution achieves high measurement precision while minimizing the increase in mechanical complexity.
Solution Approach 2:
The sensor device serves multiple functions: detecting plunger position, determining when to reduce speed, and providing feedback for control. This multi-functionality justifies the added complexity by consolidating several control functions into a single integrated system.
Data Source
AI summary
An injection device has a plunger for displacing a stopper in a syringe or carpule, a holder for the plunger, a drive for the axial displacement of the holder of the plunger, and a control device functionally assigned to the drive. The plunger, or at least a subcomponent thereof, relative to the holder, the holder is able to move over a limited distance relative to the plunger or a subcomponent thereof, opposing a pretensioning force, in that a sensor device is included which detects the relative position of the plunger, or at least a subcomponent thereof, relative to the holder, which comprises at least one sensor element which works together with the control device. The control device is designed such that, upon activation of the sensor element, the speed of advancement of the holder of the plunger is at least reduced.