Multi-Function Spring Arrangement for Drug Delivery Devices

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Solution Overview

Problem

The complexity and cost of drug delivery devices are increased by the need for multiple springs, which complicates manufacturing and assembly, and existing devices often lack a mechanism for efficiently dispensing variable user-selectable doses without requiring high user force.

Innovation Solution

A spring arrangement that serves multiple functions, including a clutch spring, stationary housing, axially movable sleeve, and button, allowing for dose setting and dispensing with reduced user force through a ratchet clutch mechanism and torsion spring, which reduces the number of required springs and simplifies assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple springs are used in drug delivery devices to perform various functions, then the device can achieve reliable operation and proper component positioning, but the manufacturing cost and device complexity increase

Engineering Contradiction:

Improvereliable operationVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple spring functions into a single integrated spring assembly. The spring member simultaneously provides biasing force for the clutch mechanism and positioning force for the actuation button, eliminating the need for separate springs for each function. This merging approach maintains reliable operation while reducing device complexity and manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The spring member is designed as a multi-functional component that performs multiple roles: it biases the clutch to maintain engagement between the drive gear and dose setting gear, simultaneously biases the actuation button to maintain engagement between the drive gear and bevel gear, and provides reset functionality. This universal component approach reduces the total number of springs needed in the device.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If multiple springs are used in drug delivery devices to perform various functions, then the device can achieve proper component positioning and engagement, but manufacturing cost increases

Engineering Contradiction:

Improvecomponent positioningVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges multiple positioning functions into a single spring member that simultaneously positions the clutch and actuation button. This reduces the total component count, simplifies assembly procedures, and lowers manufacturing costs while maintaining proper component positioning and engagement throughout device operation.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If high user force is required for dose dispensing, then the device can achieve reliable medication delivery, but the ease of operation decreases

Engineering Contradiction:

Improvemedication deliveryVSAvoidease of operation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent replaces direct manual force application with a spring-assisted mechanical system. The spring member stores and releases energy to assist the user in actuating the button and dispensing the dose, reducing the peak force requirement. The clutch mechanism with spring biasing ensures reliable engagement and medication delivery while the user only needs to overcome the spring force rather than direct mechanical resistance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution reduces manufacturing costs and complexity while enabling efficient, user-friendly dispensing of variable doses with lower user force requirements, improving the usability and affordability of drug delivery devices.

Implementation Method 1

The clutch spring is located axially interposed between the stationary housing component and the axially movable sleeve. The clutch spring applies a force on the drive sleeve in the proximal direction.

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

Methodology Applied

Scientific EffectTorsion spring energy storage: Torsion Spring

Data Source

PatentUS11185633B2Spring arrangement and drug delivery device herewith

Publication Date: 2021.11.30 SANOFI SYNTHELABO INC

AI summary

The present disclosure is directed to a spring arrangement for use in a drug delivery device and a drug delivery device including such a spring arrangement. The spring arrangement includes a clutch spring which is located axially interposed between a stationary housing component and an axially movable sleeve. The sleeve includes clutch features adapted to engage corresponding clutch features of a clutch element. The clutch spring biases the clutch features and the corresponding clutch features into engagement. The sleeve is coupled to a button such that upon actuation of the button the sleeve is translated against the bias of the clutch spring from a proximal position in which the sleeve is rotationally locked to the housing component into a distal position in which the sleeve is rotationally un-locked from the housing component. Upon release of the button the clutch spring translates the sleeve and the button into the proximal position.