Variable Dosing Injection Device Latching Mechanism
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Solution Overview
Problem
Existing injection devices have limited dosing increments, requiring multiple latching steps to reach minimum dosages and resulting in significant fluid wastage during priming, necessitating smaller increments that increase the number of latching positions.
Innovation Solution
An injection device with a latching installation that allows variable spacing of latching positions by using a threaded connection between the dosing member and injection sleeve, enabling precise control over fluid dispensing with fewer latching positions and reduced wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed dosing increments of 0.05 ml are used, then the device structure is simple, but the number of latching positions increases and fluid wastage during priming increases
Solution Approach 1:
The patent applies dynamics by making the dosing increment variable rather than fixed. The dosing member can rotate multiple times to set different dosages, and the latching positions are spaced at variable intervals. This allows the system to adapt between smaller increments for priming (reducing wastage) and larger increments for therapeutic dosing (reducing latching steps), resolving the contradiction between simple structure and reduced fluid waste.
2Loss of substance
If smaller dosing increments are used to reduce fluid wastage, then fluid wastage during priming is reduced, but the number of latching positions increases
Solution Approach 1:
The patent uses variable dosing increments that allow the user to select between smaller increments (for priming with minimal wastage) and larger increments (for therapeutic dosing with fewer latching steps). The dosing member's multiple rotations combined with variable latching position spacing enable this dynamic adjustment, resolving the contradiction between reducing fluid wastage and maintaining ease of operation.
3Measurement precision
If multiple latching positions are used to achieve precise dosing, then dosing precision is improved, but the device complexity increases
Solution Approach 1:
The patent makes the latching installation multi-functional by enabling it to serve different purposes at different stages. The same latching mechanism provides both fine precision control during priming (with smaller increments) and coarser control during therapeutic dosing (with larger increments). This universal design allows precise dosing without proportionally increasing device complexity, as the system adapts its precision requirements to the operational stage.
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
Simplifies operation by assigning a specific amount of fluid to each relative position of the dosing member and injection sleeve, reducing the number of latching positions and fluid wastage, while ensuring accurate dosing and easy resetting.
Implementation Method 1
the dosing member being connected to the injection sleeve via a first threaded connection; the dosing member being configured to rotate in a first rotational direction in relation to the housing when an amount of injection fluid to be set is being set; the injection sleeve being configured to move in the distal direction because of the first threaded connection
Data Source
AI summary
An injection device includes a housing, a dosing member held so as to be rotatable and fixed in the housing and an injection sleeve held so as to be rotationally fixed in relation to the housing and displaceable therein. A latching unit of the injection device is configured to act between two components thereof which, during setting of an amount of injection fluid to be dispensed, move relative to one another. A set amount of injection fluid is unequivocally assigned to each relative position of the two components.