Zero Position Sensing via Cam Mechanism in Medication Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing medication delivery devices face challenges in accurately sensing the zero position of a drive mechanism without requiring a significant electrical connector, which can be far removed from the electronics, complicating the detection process.
Innovation Solution
A sensing system that includes a screw element, a housing, and an electronics module with an actuator member and a biasing member, where the actuator member moves against a stop surface as the screw element reaches the zero position, triggering a sensor to recognize this position without the need for a long electrical lead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a contact point is positioned far from the electronics (e.g., distal end of dial vs. proximal end), then the zero position can be detected, but the electrical lead becomes excessively long and complex
Solution Approach 1:
The patent introduces an intermediary mechanism consisting of a cam surface and follower assembly that transfers the distal contact point's zero position detection to the proximal electronics location. The cam surface, positioned at the distal end where zero position contact occurs, converts the linear contact motion into rotational motion that is transmitted through a shorter electrical lead to the electronics at the proximal end, thereby reducing lead length while maintaining detection accuracy
Solution Approach 2:
The patent transforms the problem from a linear spatial arrangement to a rotational dimension by using a cam mechanism. Instead of extending an electrical lead along the linear axis from distal to proximal ends, the cam converts the linear zero-position contact into angular displacement, allowing the electrical lead to connect over a shorter radial distance while still capturing the zero position event
2Ease of operation
If the electronics are positioned within or near the actuator button at the proximal end, then the electronics are easily accessible, but the contact point for zero position detection is far removed
Solution Approach 1:
The cam surface acts as an intermediary that bridges the spatial gap between the proximal electronics (easily accessible at the actuator button location) and the distal zero position contact point. The cam mechanism captures the zero position event at the distal end and transmits it through a compact rotational linkage with a shortened electrical lead to the proximal electronics, maintaining both accessibility and detection capability
3Measurement precision
If an electrical lead extends a significant distance within the device, then the contact point can be reached, but the detection system becomes more complex and less reliable
Solution Approach 1:
The cam-follower mechanism serves as an intermediary that reduces the electrical lead length from a significant distance to a compact connection. By converting the distal zero position contact into rotational motion at the cam hub, the system shortens the electrical lead path, thereby improving reliability while maintaining zero position detection precision
Solution Approach 2:
The patent replaces a long electrical lead mechanical connection with a cam-based mechanical-to-mechanical transmission system. The cam mechanism converts linear contact motion into rotational motion that can be detected by a shorter electrical lead or even a non-contact sensor, reducing the reliance on long electrical leads and improving overall system reliability
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 solution allows for accurate detection of the zero position without a lengthy electrical connector, enabling efficient motion transfer from a contact point to spaced electronics, enhancing the reliability of medication delivery devices.
Implementation Method 1
a biasing member arranged to resist motion of the at least one actuator member from the first position to the second position
Implementation Method 2
a sensor within the electronics module adapted to recognize the at least one actuator member at the second position
Data Source
AI summary
A sensing system for determining a zero position of a medication delivery device. The sensing system includes at least one actuator member, a biasing member, a stop surface and a sensor. The stop surface is structured and arranged within the device housing for abutment by a push surface of the at least one actuator member as a screw element of the device screws to a zero position from a dosing position. The abutment forces the at least one actuator member to move relative to the screw element from a first position to a second position against a resistance provided by the biasing member. A sensor within an electronics module is adapted to recognize the at least one actuator member at the second position.