Cam-Guided Needle Actuator for Prolonged Self-Injection
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Solution Overview
Problem
Existing automatic injection devices face challenges in maintaining contact between the device and the target area of the patient's skin for prolonged drug delivery, especially when the volume of fluid to be administered exceeds 1 mL, leading to difficulties in self-injection and requiring hospital settings for slow IV administration.
Innovation Solution
A needle actuator assembly with a guide surface and cam surface mechanism, allowing a needle shuttle to move between positions, facilitated by a biasing member and guide post, to enable controlled injection and retraction of the needle, along with a button actuator to manage the injection process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the volume of fluid to be administered is increased above 1 mL, then the injection time becomes longer, but the patient has difficulty maintaining contact between the device and the target area of the skin
Solution Approach 1:
The needle actuator assembly employs a dynamic cam surface mechanism that automatically adjusts the needle shuttle position and injection parameters during the procedure. The cam surface geometry transforms the actuator's linear motion into controlled needle insertion, medication delivery, and automatic retraction, maintaining optimal skin contact throughout the extended injection period for larger volumes
Solution Approach 2:
The device incorporates automatic needle retraction functionality where the cam surface mechanism autonomously returns the needle to its initial position after medication delivery without requiring manual intervention. This self-service feature ensures continuous skin contact and eliminates the need for the patient to maintain manual pressure or contact during prolonged injection
2Quantity of substance
If the injection time is extended for larger volumes, then more drug can be administered, but the device requires hospital settings with IV administration
Solution Approach 1:
The injection system is segmented into distinct functional modules: a reservoir for medication storage, a needle assembly with shuttle mechanism, a cam surface actuator, and a biasing member for automatic retraction. This segmentation allows each component to perform its specific function efficiently, enabling extended-volume administration through a manageable, modular device structure rather than requiring complex IV systems
Solution Approach 2:
The cam surface acts as an intermediary mechanism that translates simple user actuation into complex coordinated movements of the needle shuttle, plunger, and retraction system. This intermediary mechanism enables the device to deliver larger volumes through controlled, extended injection without requiring the complexity of hospital-based IV administration systems
3Duration of action of moving object
If a traditional IV method is used for slow drug injection, then large volumes can be administered over time, but the procedure requires hospital or outpatient settings
Solution Approach 1:
The device is designed for self-injection with automatic operational sequences. The cam surface mechanism automatically controls needle insertion, medication delivery over the required duration, and needle retraction. The biasing member provides automatic resetting functionality, allowing the device to be prepared for subsequent use without manual intervention, enabling patients to self-administer extended-duration injections at home
Solution Approach 2:
The invention replaces the complex mechanical and procedural requirements of traditional IV systems with a streamlined cam-based mechanical actuation system. The cam surface geometry encodes the entire injection sequence, substituting the need for hospital-based IV infrastructure and professional administration with a simple, self-contained mechanical device that patients can operate independently
Data Source
AI summary
A needle actuator assembly for a drug delivery system includes a needle actuator body having a guide surface, a needle shuttle having a cam surface, with the needle shuttle moveable along a vertical axis between a first position and a second position. The needle shuttle is configured to move between the first and second position through engagement between the guide surface of the needle actuator body and the cam surface of the needle shuttle. The assembly further including a needle received by the needle shuttle.