Injection Dose Adjustment Assembly With Bidirectional Ratchet Control
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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 for bidirectional rotation and precise dose control through audible feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional ratchet wheel and pawl adjustment mechanism is used, then the injection dose can be adjusted in one direction (clockwise), but the inner mounting tube cannot rotate in reverse direction (counterclockwise) to return to a predetermined dose scale
Solution Approach 1:
The ratchet arms are designed with resilient properties that allow them to dynamically adapt their engagement state. When rotating clockwise, the ratchet arms engage with the ratchet teeth to prevent reverse rotation. When rotating counterclockwise, the resilient ratchet arms can disengage from the ratchet teeth, allowing reverse rotation to return to predetermined dose scales. This dynamic engagement/disengagement mechanism enables bidirectional rotation while maintaining one-way locking capability.
2Ease of operation
If the ratchet arms are made resilient, then the mounting sleeve can rotate bidirectionally, but the structure becomes more complex
Solution Approach 1:
The resilient ratchet arms combine multiple functions into a single component: they provide one-way locking through engagement with ratchet teeth, enable bidirectional rotation through controlled disengagement, and offer audible feedback through clicking sounds during rotation. By merging these functions into the ratchet arm structure itself, the design avoids adding separate complex mechanisms for each function.
3Measurement precision
If the dose adjusting knob selectively engages with or disengages from the elastic transmission element, then precise dose control is achieved, but the mechanism complexity increases
Solution Approach 1:
The elastic transmission element and ratchet mechanism are designed to automatically engage and disengage based on the rotation direction and force applied. During clockwise rotation, the resilient ratchet arms naturally engage with the ratchet teeth to provide locking. During counterclockwise rotation, they automatically disengage to allow reverse rotation. This self-service engagement mechanism eliminates the need for additional complex control systems.
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 bidirectional adjustment of injection doses, ensuring accurate dose settings and user-friendly operation with distinct auditory cues for direction identification.
Implementation Method 1
The elastic transmission element is mounted on a rear end of the mounting sleeve and is able to provide an axial elastic preload
Implementation Method 2
When the mounting sleeve is rotated, a resilient potential energy is formed in the resilient element that is driven by the driving ring
Implementation Method 3
The mounting sleeve has two resilient ratchet arms being able to abut against two of the one-way ratchet teeth of the inner ratchet portion respectively
Data Source
AI summary
An injection dose adjustment assembly is connected with an injection assembly to form an injection mechanism, and is further coupled with a vial mounting tube to form an injection syringe. The injection dose adjustment assembly has a mounting sleeve mounted in an outer tube. Two resilient ratchet arms of the mounting sleeve abut against two different one-way ratchet teeth of an inner ratchet portion of the outer tube respectively. An elastic transmission element and a pressing element are mounted on the mounting sleeve. A dose adjusting knob is mounted on the outer tube and is rotatable in a first direction and a second direction. By rotating the mounting sleeve through the elastic transmission element, an injection dose can be adjusted and a moving distance of an injection push rod of the injection assembly can be controlled.