Syringe Plunger with Rotational Dose Dial and Detent Mechanism
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Solution Overview
Problem
Existing syringes require users to visually measure medication levels, making it difficult to draw accurate doses due to closely spaced scale markings and high static friction, leading to potential over- or under-dosing.
Innovation Solution
A syringe with a plunger featuring dose settings indicated on its surface, including numeric values and rib and detent mechanisms for precise dose selection, along with a transparent body for easy viewing, and a thread engagement system that reduces start-up force and allows for adjustable increments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scale markings are used on the syringe barrel to measure medication volume, then the user can determine the dosage amount, but the closely spaced markings make it difficult to read and draw accurate doses
Solution Approach 1:
The patent transitions from a two-dimensional scale marking system on the barrel to a three-dimensional rotational dial mechanism on the plunger. The dosage selection is moved from linear axial movement to rotational movement with tactile feedback, allowing users to select doses by rotating the plunger to align dosage indicators with reference marks, thereby improving both readability and measurement precision.
Solution Approach 2:
The patent introduces a dial mechanism with dosage indicators as an intermediary between the user and the medication volume. This intermediary system provides tactile feedback through rib and detent mechanisms, allowing users to accurately select dosages without directly reading closely spaced scale markings on the barrel.
2Manufacturing precision
If the plunger is moved axially to draw medication, then the desired volume can be drawn into the syringe, but high static friction makes it easy to overshoot the desired dose setting
Solution Approach 1:
The patent changes the plunger movement from linear axial motion to rotational motion. The rotational mechanism with rib and detent features provides dynamic tactile feedback during rotation, allowing users to easily detect and stop at precise dosage positions. This dynamic rotational system overcomes the high static friction problem by distributing the force requirement across multiple engagement points during rotation.
Solution Approach 2:
The patent employs periodic engagement through the rib and detent mechanism, where the plunger rotates through a series of discrete tactile positions corresponding to different dosage increments. This periodic engagement provides natural stopping points that prevent overshooting, as users can feel each incremental position during rotation.
3Measurement precision
If the user carefully controls plunger movement to achieve precise dosing, then accurate dosage can be obtained, but this requires repeated adjustments above and below the desired setting
Solution Approach 1:
The patent allows users to pre-select the desired dosage by rotating the plunger to the target position before drawing medication. The rotational dial with clearly marked dosage indicators enables users to visually identify and tactilely confirm the desired dose setting in advance, eliminating the need for repeated adjustments during the medication drawing process.
Solution Approach 2:
The patent incorporates visual feedback through dosage indicators aligned with reference marks and tactile feedback through the rib and detent mechanism. This dual feedback system allows users to immediately confirm when the desired dosage is selected, preventing overshooting and eliminating the need for repeated trial-and-error adjustments.
4Ease of operation
If the syringe body is made transparent for easy viewing of dose settings, then dosage can be easily monitored, but this may increase manufacturing complexity
Solution Approach 1:
The patent divides the syringe into distinct functional segments: a transparent body portion for viewing and a separate plunger assembly with dosage indicators. This segmentation allows the transparent body to be manufactured using standard techniques while the plunger assembly incorporates the rotational dosage selection mechanism, balancing ease of viewing with manufacturing feasibility.
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
Facilitates easy and accurate dose selection with reduced user effort, ensuring the correct amount of medication is drawn and delivered, while maintaining compatibility with existing manufacturing costs and techniques.
Implementation Method 1
a thread engagement system that reduces start-up force and allows for adjustable increments
Implementation Method 2
rib and detent mechanisms for precise dose selection
Data Source
Figure 1
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AI summary
A syringe includes a body for receiving a medicament and a plunger movably connected to the syringe body. The plunger is moved with respect to the syringe body to draw in and dispense the medicament. A plurality of dose setting indicators are disposed on the plunger. The plunger is rotated outwardly from the syringe body to draw medicament into the syringe body. The plunger can be pushed or rotated into the syringe body to dispense the medicament.