Sliding Pen Injector Cover With Optical Plunger Position Sensing
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Solution Overview
Problem
Existing liquid delivery devices, particularly pen injectors, lack reliable mechanisms for monitoring the timing and quantity of previously administered doses and the remaining drug quantity.
Innovation Solution
Integrate sensors with a sliding cover of the liquid delivery system to measure the plunger position, utilizing optical and other sensors to determine the plunger's location and quantity of drug delivered, with features like cradles and load cells for precise measurement and data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical sensors are integrated into the sliding cover to measure plunger position, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The optical sensor is integrated directly into the sliding cover structure, merging the sensing function with the mechanical cover component. This consolidation reduces the need for separate sensor mounting structures and simplifies the overall device architecture while maintaining measurement precision.
Solution Approach 2:
The sliding cover serves multiple functions: it protects the needle, provides a user interface for operation, and now also houses the optical sensor for plunger position detection. By making the cover multi-functional, the patent reduces the need for additional components and simplifies the device structure.
2Reliability
If multiple optical sensors are used to detect plunger position through the transparent cylinder, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
Instead of using multiple sensors across the entire cylinder, the patent places a single optical sensor at a specific location on the sliding cover that corresponds to a critical measurement point. This localized sensing approach maintains reliability for the specific measurement need while minimizing device complexity.
Solution Approach 2:
The patent extracts only the essential measurement function from a potential array of sensors, using a single optical sensor to detect plunger position through the transparent cylinder at the moment when the sliding cover reaches a predefined position. This extraction of the core function reduces complexity while maintaining measurement reliability.
3Device complexity
If the sliding cover is used as the sensor housing, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The optical sensor is pre-positioned and fixed within the sliding cover during manufacturing, with its location carefully predetermined to correspond to the measurement point. This preliminary positioning ensures that when the sliding cover moves to the predefined position, the sensor is automatically in the correct location for accurate measurement, reducing the need for complex real-time adjustments.
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
Provides accurate tracking of administered doses and remaining drug quantity, enabling display and transmission of data for user awareness and external processing.
Implementation Method 1
an optical sensor having an optical emitter for emitting radiation and an optical receiver for generating the plunger sensor output indicative of an amount of said radiation received by said optical receiver
Implementation Method 2
measuring the position of a plunger of the liquid delivery system while the cover is being removed or replaced
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
A sliding cover for a liquid delivery device, such as a cap (100) for a pen injector (200), incorporates a set of sensors including a first optical sensor (110) with an output which changes during uncapping or capping motions on passing of a plunger (220) of the pen injector. This output is used together with at least one additional sensor output to determine the position of the plunger along a cylinder (210) of the liquid delivery device. By monitoring changes in the plunger position, the quantity of dosages delivered by the liquid delivery device can be determined, displayed, stored and/or transmitted to an external device for further data processing or storage.