Injection Dose Adjustment Assembly for Bidirectional Ratchet Dosing
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Solution Overview
Problem
Conventional dose metering syringes lack the ability to adjust injection doses in both clockwise and counterclockwise directions, limiting incremental adjustments and causing inconvenience when users need to revert to a predetermined dose scale.
Innovation Solution
An injection dose adjustment assembly featuring an outer tube with one-way ratchet teeth, a mounting sleeve with resilient ratchet arms, an elastic transmission element, and a dose adjusting knob, allowing bidirectional rotation for precise dose adjustment with audible feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a unidirectional ratchet mechanism is used for dose adjustment, then the structure is simple and reliable, but the user cannot rotate reversely to return to a predetermined dose scale
Solution Approach 1:
The ratchet mechanism is designed with resilient ratchet arms that can dynamically switch between engaged and disengaged states. The resilient element allows the ratchet arms to flex and release from the ratchet teeth under sufficient force, enabling bidirectional rotation while maintaining structural simplicity. This dynamic behavior resolves the contradiction by allowing reverse rotation when needed while preserving the simple unidirectional design during normal operation.
2Reliability
If the resilient ratchet arms are always engaged with the ratchet teeth, then the structure is stable, but the mounting sleeve cannot be rotated reversely
Solution Approach 1:
The resilient element is pre-loaded to maintain the ratchet arms in an engaged state with the ratchet teeth, ensuring stable unidirectional rotation during normal dose adjustment. When reverse rotation is needed, the user applies sufficient force to preliminarily overcome this pre-loaded resilience, temporarily disengaging the ratchet arms to enable counterclockwise rotation. This preliminary engagement design resolves the contradiction by providing stable operation during normal use while allowing controlled reversibility when required.
3Adaptability or versatility
If a bidirectional rotation mechanism is implemented, then the user can adjust dose in both directions, but the structure becomes more complex
Solution Approach 1:
The resilient ratchet arms serve a dual function: they automatically engage with the ratchet teeth to enable unidirectional rotation during normal operation, and they can be manually disengaged by applying sufficient force to enable reverse rotation. This self-service mechanism eliminates the need for separate bidirectional control mechanisms, achieving bidirectional dose adjustment while maintaining structural simplicity. The system essentially regulates itself based on the user's rotational intent.
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 precise and intuitive dose adjustment in both directions with audible feedback, ensuring accurate incremental changes and overcoming the limitations of unidirectional ratchet mechanisms.
Implementation Method 1
an elastic transmission element mounted on a rear end of the mounting sleeve and capable of providing an axial elastic preload
Implementation Method 2
a resilient element mounted in the mounting sleeve and disposed between the driving ring and an inner wall of a rear end of the mounting sleeve to provide a resilient force
Data Source
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AI summary
An injection dose adjustment assembly (A) is connected with an injection assembly (B) to form an injection mechanism, and is further coupled with a vial mounting tube (D) to form an injection syringe. The injection dose adjustment assembly (A) has a mounting sleeve (20) mounted in an outer tube (10). Two resilient ratchet arms (21) of the mounting sleeve (20) abut against two different one-way ratchet teeth (121) of an inner ratchet portion (12) of the outer tube (10) respectively. An elastic transmission element (40) and a pressing element (60) are mounted on the mounting sleeve (20). A dose adjusting knob (50) is mounted on the outer tube (10) and is rotatable in a first direction and a second direction. By rotating the mounting sleeve (20) through the elastic transmission element (40), an injection dose can be adjusted and a moving distance of an injection push rod (70) of the injection assembly (B) can be controlled.