Injection Device Ratcheting Mechanism for Precise Dose Control
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Solution Overview
Problem
Existing injection devices lack the ability to deliver a defined dose of a liquid product, such as medicaments, consistently and prevent additional doses after the last defined dose is released.
Innovation Solution
An injection device featuring a threaded rod with teeth, a rotating sleeve, and a guide sleeve with engaging elements that create a non-self-inhibiting thread connection, allowing for precise dosing and preventing further dosing after the last defined dose is administered, utilizing a ratcheting mechanism and abutments to ensure accurate and controlled delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rotating sleeve is used for variable dosing, then dosing flexibility is improved, but device complexity increases
Solution Approach 1:
The dosing mechanism is segmented into a rotating sleeve with multiple discrete positioning detents, each corresponding to a specific dose volume. This segmentation allows variable dosing through simple rotational steps rather than continuous adjustment, reducing mechanical complexity while maintaining dosing flexibility.
Solution Approach 2:
A ratcheting mechanism with pawls and teeth acts as an intermediary between the rotating sleeve and the plunger rod. This intermediary component translates rotational motion into controlled linear motion with precise positioning, enabling flexible dosing without requiring complex direct coupling mechanisms.
2Reliability
If multiple engaging elements are used to prevent additional doses, then reliability is improved, but device complexity increases
Solution Approach 1:
The ratcheting mechanism combines multiple engaging elements (pawls and teeth) into a single integrated component structure. The pawl- tooth engagement is merged with the dosing rotation mechanism, allowing the same structure to both set the dose and prevent reverse rotation, thereby preventing additional doses without adding separate complex mechanisms.
Solution Approach 2:
The rotating sleeve serves multiple functions: it sets the dose volume through rotation, engages the ratcheting mechanism to lock the position, and prevents reverse rotation to block additional dosing. This multi-functionality reduces the need for separate components, maintaining reliability while controlling complexity.
3Measurement precision
If a non-self-inhibiting thread connection is used, then dosing precision is improved, but ease of operation worsens
Solution Approach 1:
The ratcheting mechanism with pawls and teeth serves as an intermediary that mediates between the user's rotational input and the plunger's linear movement. It translates the rotation into precise linear dosing through controlled engagement, maintaining dosing precision while allowing easy rotation operation without self-inhibition.
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 the precise delivery of defined doses of liquid products, including medicaments, with a mechanism to prevent additional doses after the last dose is released, ensuring consistent and controlled administration.
Implementation Method 1
The engaging mechanism of the engaging elements of the rotating sleeve and of the guide sleeve into the teeth of the threaded rod may be configured as a ratcheting mechanism
Implementation Method 2
The dosing sleeve can be in a threaded engagement with a rotating sleeve
Data Source
AI summary
An injection device for dosing and for releasing a defined dose of a liquid product includes: a threaded rod with a thread that includes teeth; a rotating sleeve with an engaging element that can engage with the teeth of the threaded rod; a guide sleeve having an engaging element that can engage with the teeth of the threaded rod; and a dosing sleeve arranged in an axially moveable manner in relation to the rotating sleeve and the guide sleeve, the dosing sleeve in a threaded engagement with the rotating sleeve.