Curved Locking Surface Injection Device Trigger Actuation

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Solution Overview

Problem

Users struggle to operate existing injection devices correctly due to the difficulty in determining if the sliding sleeve is fully retracted and the high force required to actuate the trigger, leading to accidental activation and potential device damage.

Innovation Solution

The injection device incorporates a curved surface on the contact portion of the locking mechanism, reducing the force needed to actuate the trigger and facilitating easier retraction, while maintaining safety and accuracy through precise axis alignment and contact geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a flat contact portion is used on the locking mechanism, then the structure is simple, but excessive force is required to actuate the trigger and retract the locking mechanism

Engineering Contradiction:

Improveforce required to actuate triggerVSAvoidease of trigger actuation

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The contact portion of the locking mechanism is designed with a curved surface instead of a flat surface. This curvature allows the trigger to engage more effectively with the locking mechanism during retraction, reducing the force required by the user while maintaining reliable locking engagement when closed.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the sliding sleeve is not fully retracted, then the device remains safe, but the user cannot activate the trigger due to tight tolerances

Engineering Contradiction:

Improveprevention of accidental activationVSAvoidease of trigger activation

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The curved contact surface provides a gradual transition during the retraction of the locking mechanism. As the trigger moves, the curved surface guides the engagement and disengagement process, making it easier for the user to achieve full retraction and activate the trigger while maintaining a clear safety margin.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Ease of operation

If excessive force is applied to the trigger, then the user may force the injection device, but this can damage the injection mechanism

Engineering Contradiction:

Improveease of forcing retractionVSAvoiddamage to injection mechanism

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The curved contact surface distributes the applied force more evenly during trigger actuation. This reduces stress concentration on specific components of the injection mechanism, allowing users to retract the locking mechanism with less force while minimizing the risk of damage to internal components.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 curved surface design enhances user dexterity by reducing the force required for activation and assists in retracting the locking mechanism, ensuring accurate and safe operation of the device.

Implementation Method 1

The contact portion comprises a curved surface

Methodology Applied

Scientific EffectCurved surface contact geometry: Geometry

Data Source

PatentUS11173255B2Injection device

Publication Date: 2021.11.16 CILAG GMBH INTERNATIONAL

AI summary

An injection device comprises an actuator adapted when actuated to cause commencement of an injection sequence; a locking mechanism adapted to be moved between a locked position in which the locking mechanism prevents the actuator from being actuated, and an unlocked position in which the actuator can be actuated to cause commencement of the injection sequence. The locking mechanism comprises a contact portion which in the locked position of the locking mechanism projects against the actuator. The contact portion comprises a curved surface.