Injection Dose Setting Mechanism With Independent Locking

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Solution Overview

Problem

Existing injection devices lack a reliable mechanism for setting and dispensing doses, leading to risks of incorrect operation and potential overdosing due to the interdependence of setting and priming processes.

Innovation Solution

A dose setting mechanism featuring a setting sleeve and a rotating sleeve with axial stops and a locking mechanism, allowing for independent setting and priming operations, ensuring accurate dose selection and prevention of overdosing by restricting rotational movement and using a threaded rod for precise dosing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the setting element and drawing element are coupled together, then the structure is simpler, but the risk of incorrect operation and overdosing increases due to interdependence

Engineering Contradiction:

Improvestructure simplicityVSAvoidrisk of incorrect operation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent divides the dose setting mechanism into two independent functional elements: a setting element for dose selection and a drawing element for dose delivery. These elements are mechanically separated, allowing the setting element to be locked independently while the drawing element can be actuated separately, thereby eliminating the risk of incorrect operation while maintaining structural simplicity through modular design

Inventive Principle:

Principle #1Segmentation

2Ease of operation

If the drawing element can rotate freely, then the ease of operation is improved, but the manufacturing precision of dose setting is compromised

Engineering Contradiction:

Improveease of priming operationVSAvoiddose setting precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent implements dynamic control where the drawing element's rotational freedom is conditionally restricted. During the priming operation, the drawing element can rotate freely for ease of operation. However, when the setting element is locked in a specific dose position, the drawing element's rotation is mechanically restricted to prevent imprecise dosing. This dynamic state change allows the system to optimize for either operation ease or precision depending on the operational phase

Inventive Principle:

Principle #15Dynamics

3Reliability

If the setting element is locked during priming, then the reliability of dose setting is improved, but the ease of operation deteriorates

Engineering Contradiction:

Improvedose setting reliabilityVSAvoidease of priming operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies preliminary action by locking the setting element before the priming operation begins. This ensures that the dose is pre-set and cannot be accidentally changed during the priming process. The locking mechanism is designed to engage automatically when the setting element reaches the desired dose position, providing reliability without requiring additional manual intervention during priming

Inventive Principle:

Principle #10Preliminary action

4Manufacturing precision

If the drawing element is restricted from rotating, then the manufacturing precision of dose delivery is improved, but the ease of operation worsens

Engineering Contradiction:

Improvedose delivery precisionVSAvoidease of priming operation

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

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

The mechanism allows for reliable and accurate setting and dispensing of doses, reducing the risk of incorrect operation and ensuring that only the set dose is administered, with the ability to prevent overdosing by locking the system at the last dose setting.

Implementation Method 1

a threaded rod (4), which is capable of being moved relative to the rotating sleeve (3) in an axial direction

Methodology Applied

Scientific EffectScrew mechanism: Screw

Implementation Method 2

A stop (2b) is on the setting element (2), and a counter stop (3g) is on the drawing element (3) so that a rotational motion of the drawing element (3) relative the setting element (2) can be limited by the stops (2b, 3g)

Methodology Applied

Scientific EffectMechanical stop: Mechanical Force

Data Source

PatentUS8721601B2Dose setting mechanism for an injection device

Publication Date: 2014.05.13 PFIZER INC

AI summary

A dosing device for setting a dose to be delivered by an injection device, the dosing device including a setting element, e.g. a setting sleeve, and a drawing element, e.g. a rotating sleeve, which can be rotated out of the dosing device for preparing a dose delivery. A stop is on the setting element, and a counter stop is on the drawing element so that a rotational motion of the drawing element relative the setting element can be limited by the stops. The present invention encompasses a method for setting a dose that should be delivered by an injection device, wherein the dose to be delivered can be set by a setting element, e.g. a setting sleeve, and a drawing element of the injection device, e.g. a rotating sleeve, can subsequently draw up the dose by effecting a rotational motion to deliver the set dose from the injection device in a subsequent step. According to the present invention, the setting process is isolated from drawing process.