Auto-Injector Driving Mechanism for Precise Plunger Control
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Solution Overview
Problem
Conventional auto-injectors fail to meet requirements of small volume, high driving power, long driving distance, long injecting period, and accurate drug dose delivery rate.
Innovation Solution
A driving mechanism for an auto-injector comprising a first transmission component, a driving component, a driving resilient component, a stopping resilient component, a third transmission component, a sliding component, and a supporting component, which enables a plunger to slide relative to a reservoir with high efficiency and precision, preventing rotation during the sliding movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional auto-injector mechanisms are used, then the device structure is simple, but the driving power is insufficient and driving distance is short
Solution Approach 1:
The transmission system is divided into multiple independent components: first transmission component (driving gear), second transmission component (driven gear), third transmission component (worm gear), and sliding component. Each component performs a specific function in the power transmission chain, enabling high driving power through modular segmentation while keeping individual components relatively simple.
Solution Approach 2:
The resilient component acts as an intermediary between the first and second transmission components, transmitting driving force while accommodating misalignment and reducing impact. The resilient component mediates the power transmission, allowing the system to achieve high driving power without requiring complex rigid coupling mechanisms.
2Productivity
If fast injection is implemented, then productivity is high, but injection accuracy and dose delivery precision deteriorate
Solution Approach 1:
The worm gear (third transmission component) replaces direct mechanical coupling between the driving and sliding components. The worm gear provides self-locking capability and precise motion control, allowing the sliding component to move at controlled speeds with high positioning accuracy, thereby maintaining dose delivery precision even during faster injection cycles.
Solution Approach 2:
The sensor detects the position of the sliding component and provides feedback to the control unit. The control unit adjusts the driving component's operation based on this feedback, ensuring accurate dose delivery by monitoring and controlling the sliding component's position throughout the injection process, regardless of injection speed.
3Duration of action of moving object
If short injection period is used, then productivity increases, but driving distance and power requirements increase
Solution Approach 1:
The driving component operates in periodic cycles, alternating between driving the sliding component forward and returning to the initial position. This periodic action allows the injection to be completed in discrete stages over an extended period, reducing the peak driving power requirements while maintaining productivity through efficient use of each driving cycle.
Solution Approach 2:
The resilient component provides dynamic cushioning during the power transmission process, absorbing shocks and varying the force transmission according to the instantaneous loading conditions. This dynamic response allows the system to maintain effective driving power throughout the injection period without requiring excessive peak power, enabling longer injection periods with moderate power requirements.
4Measurement precision
If the sliding component can rotate during sliding, then the mechanism is simpler, but injection accuracy deteriorates
Solution Approach 1:
The guiding structure employs asymmetric geometry where the sliding component has a specific shape that fits into a corresponding asymmetric guiding portion. This asymmetric design naturally prevents rotation of the sliding component during sliding, ensuring that the component moves only in the intended linear direction with high positioning accuracy, while keeping the guiding structure relatively simple.
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, allowing for a long sliding distance, slow sliding speed, and accurate drug dose delivery, meeting the requirements of small volume, high driving power, long injecting period, and precise drug delivery.
Implementation Method 1
The driving resilient component is configured to be forced by the first transmission component to resiliently deform to push the second transmission component to rotate along a first rotating direction, or the driving resilient component is configured to be released to resiliently recover
Implementation Method 2
The stopping resilient component is forced by the second transmission component to resiliently deform when the driving resilient component is forced by the first transmission component to resiliently deform to push the second transmission component to rotate along the first rotating direction. The stopping resilient component engages with the second transmission component for stopping the second transmission component from rotating along a second rotating direction opposite to the first rotating direction
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 and includes a first transmission component(131,131',131"), a driving component(132), a second transmission component(133), a driving resilient component(134), a stopping resilient component(135), a third transmission component(136), a sliding component(137) and a supporting component(138). The second transmission component(133) resiliently deforms the stopping resilient component(135) when the first transmission component(131,131',131") resiliently deforms the driving resilient component(134) to push the second transmission component(133) to rotate along a first rotating direction(R1). The second transmission component(133) is stopped from rotating along a second rotating direction(R2) by the stopping resilient component(135) when the driving resilient component(134) is released to resiliently recover. The third transmission component(136) drives the sliding component(137) to slide when the second transmission component(133) rotates. The supporting component(138) guides the sliding component(137) to slide. Besides, a related auto-injector(1) is provided.