Automatic Medication Injection Device with Needle Retraction
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Solution Overview
Problem
Existing automatic medication injection devices often require user intervention for needle retraction, can have variable injection speeds, and are bulky, making them inconvenient to use.
Innovation Solution
An automatic medication injection device with a trigger assembly that automatically inserts and retracts the needle, featuring a biased drive element and spring mechanism for consistent speed control, allowing for easy handling and use without manual needle withdrawal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the device requires user intervention for needle retraction, then the device structure can be simpler, but the ease of operation deteriorates
Solution Approach 1:
The device automatically retracts the needle after injection without requiring user intervention. The spring mechanism self-activates to retract the needle assembly into the housing, making the system serve itself and eliminating the need for manual needle withdrawal by the user.
Solution Approach 2:
The spring mechanism is pre-loaded in a compressed state during device assembly, storing elastic potential energy. When the trigger is released, this pre-stored energy automatically drives the needle retraction action, eliminating the need for additional user input or complex control systems.
2Reliability
If the injection speed varies during use, then the device can be simpler to operate, but the reliability deteriorates
Solution Approach 1:
The spring mechanism is designed with specific mechanical parameters (spring constant, pre-compression distance, engagement geometry) that ensure consistent force application throughout the injection stroke. This controlled parameter design maintains constant injection speed, improving reliability without requiring complex electronic speed control systems.
3Ease of operation
If the device is made bulky, then the structural integrity and functionality can be improved, but the ease of operation deteriorates
Solution Approach 1:
The needle assembly is nested within the housing in a retracted position, and the spring mechanism is compactly integrated within the same housing volume. This nested arrangement minimizes the overall device volume while maintaining all necessary functional components for automatic injection and retraction.
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
Enables automatic needle insertion and retraction without user intervention, providing a consistent and convenient injection experience by ensuring needle insertion and injection occur at a constant speed.
Implementation Method 1
featuring a biased drive element and spring mechanism for consistent speed control
Data Source
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AI summary
An automatic medication injection device including a driver (95), a retractor (190, 230) and a blocking member (180). Upon device triggering the driver is shifted proximally to move a device syringe, expel medication from the syringe0, and then to disengage itself from the syringe plunger. The driver and the blocking member have a complementary camming configuration by which the blocking member, during the driver shifting, is automatically rotated from a first rotational orientation to a second rotational orientation. The blocking member blocks retraction of the retractor when disposed in the first rotational orientation, and permits retraction of the retractor when disposed in the second rotational orientation, which retractor retraction withdraws the device syringe from an injecting position to a retracted position.