Auto-Injector Plunger Drive With Anti-Rotation Guided Sliding
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Solution Overview
Problem
Conventional auto-injectors face challenges in achieving small volume, high driving power, long driving distance, long injecting period, and accurate drug dose delivery rate, with existing devices having complicated structures and inadequate performance.
Innovation Solution
A driving mechanism comprising a first transmission component, a driving component, a second transmission component, a third transmission component, a sliding component, and a bracket, which allows the sliding component to slide relative to a reservoir without rotation, utilizing a worm screw, worm gear, screw sleeve, and screw rod configuration with a guiding structure to ensure precise drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional auto-injector structures are used, then the device can deliver drug doses, but the structure is complicated and cannot achieve high driving power with small volume
Solution Approach 1:
The patent employs nested transmission components where the first transmission component (worm screw) is integrated with the second transmission component (worm gear), which in turn connects to the third transmission component (screw sleeve). This nested arrangement allows multiple transmission stages to be compactly arranged within a small volume while maintaining high driving power through cumulative mechanical advantage.
Solution Approach 2:
The driving mechanism is segmented into multiple independent transmission components (worm screw, worm gear, screw sleeve) that work in sequence. Each component handles a specific stage of power transmission, allowing the system to achieve high overall transmission ratio and driving power while keeping each individual component compact and the total device volume small.
2Duration of action of moving object
If conventional transmission mechanisms are used, then power can be transmitted, but the sliding distance is short and injecting period is short
Solution Approach 1:
The second transmission component (worm gear) acts as an intermediary between the first transmission component (worm screw) and the third transmission component (screw sleeve). This intermediary stage multiplies the rotational motion and transmits it to the screw sleeve, enabling the sliding component to achieve both long sliding distance and controlled sliding speed, thereby extending the injecting period.
3Measurement precision
If simple transmission structures are used, then the device is compact, but accurate drug dose delivery rate cannot be achieved
Solution Approach 1:
The patent employs a dynamic guiding structure where the guiding portion includes a sliding through hole with arc parts and flat parts that correspond to arc and flat parts on the sliding component. This dynamic geometric constraint system precisely controls the sliding component's motion trajectory and prevents rotation, ensuring accurate drug dose delivery rate while maintaining relatively simple overall structure.
4Measurement precision
If the sliding component can rotate during sliding, then the mechanism is simpler, but the drug dose delivery rate becomes inaccurate
Solution Approach 1:
The guiding structure employs asymmetric geometric features with arc parts and flat parts on both the guiding portion and the sliding component. This asymmetric design creates a precise mechanical constraint that allows sliding motion in one direction while preventing rotation, thereby ensuring accurate drug dose delivery rate without requiring complex active control mechanisms.
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
The mechanism achieves a compact structure with high power and efficiency, enabling a long sliding distance, slow sliding speed, and accurate drug dose delivery, meeting requirements of small volume, high driving power, and long injecting period.
Implementation Method 1
The first transmission component is a worm screw. The second transmission component is a worm gear.
Implementation Method 2
The third transmission component is a screw sleeve. The sliding component is a screw rod
Implementation Method 3
The guiding portion includes a sliding through hole structure. The sliding component slidably passes through the sliding through hole structure. A cross section of the sliding component matches with a cross section of the sliding through hole structure.
Data Source
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AI summary
A driving mechanism(13) for driving a plunger(12) of an auto-injector(1) to slide relative to a reservoir(11) of the auto-injector(1) is provided. The driving mechanism(13) includes a first transmission component(131), a driving component(132), a second transmission component(133), a third transmission component(134), a sliding component(135) and a bracket(136). The driving component(132) is for driving the first transmission component(131) to rotate to drive the second transmission component(133) to rotatably drive the third transmission component(134) rotate together with the second transmission component(133), so as to drive the sliding component(135) to slide relative to the third transmission component(134) by the third transmission component(134) to push the plunger(12) to pump a drug out of the reservoir(11). The sliding component(135) passes through a guiding portion(1361) of the bracket(136), and the guiding portion(1361) is configured to guide the sliding component(135) to slide without any rotation. Besides, a related auto-injector(1) is provided.