Segmented Plunger Auto-Injector for Compact Medicament Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional injection devices, both manual and auto-injectors, face challenges such as incomplete dose delivery, user dexterity issues, and device length, making it difficult for elderly or those with dexterity problems to administer injections accurately and comfortably.
Innovation Solution
A compact auto-injector design featuring a plurality of stacked, circular-disk shaped plunger elements connected by a cord, with a driving actuator providing constant force for aligned plunger elements to ensure complete medicament delivery, featuring a drive spring and activation arrangement for efficient medicament dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional plunger arrangements are used in auto-injectors, then the device can deliver liquid medicament, but the housing length increases and portability is reduced
Solution Approach 1:
The plunger is divided into multiple stacked plunger elements (first, second, and third plunger elements) that can be independently positioned along the syringe axis. This segmentation allows the plunger mass to be distributed and repositioned within a compact housing space, reducing the overall housing length while maintaining the ability to deliver the complete medicament dose through coordinated movement of all elements.
Solution Approach 2:
The plunger elements are arranged in a stacked configuration along the syringe axis, utilizing the longitudinal dimension efficiently. This dimensional arrangement allows multiple functional elements to occupy space along the injection axis rather than requiring extended lateral space, thereby compacting the housing length while preserving dosing capability.
2Ease of operation
If manual plunger depression is used, then the device structure is simple, but users with dexterity problems cannot administer injections accurately
Solution Approach 1:
The auto-injector is designed to perform the plunger depression function automatically through a trigger mechanism that activates the plunger elements to move and expel the medicament. This self-service approach eliminates the need for the user to manually depress the plunger, making the device easy to operate for users with dexterity problems while the internal complexity is managed through automated mechanical actuation.
Solution Approach 2:
The manual mechanical action of plunger depression is replaced with an automated mechanical actuation system. The trigger mechanism initiates a mechanical sequence that automatically positions and moves the plunger elements, substituting the complex manual coordination required in conventional devices with a simplified user action that activates an automated mechanical response.
3Ease of operation
If the plunger button is extended for easy reaching, then users can access it, but the device length increases and portability is reduced
Solution Approach 1:
The trigger mechanism is integrated into the housing structure at a position that is easily accessible to users, merging the activation function with the housing design rather than extending it outward. This integration allows the trigger to be reached comfortably without increasing the overall device length, maintaining portability while ensuring ease of operation.
Solution Approach 2:
The trigger mechanism is positioned and designed to provide dynamic accessibility, allowing users to activate the device from a natural grasping position. The trigger's placement and movement characteristics enable easy activation without requiring the device to be extended, adapting the interaction to user ergonomics while maintaining compact dimensions.
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 auto-injector ensures a consistent and complete delivery of the medicament dose, improving user safety and convenience by reducing manual force requirements and device length, making it more accessible for various user groups.
Implementation Method 1
The driving actuator may comprises a drive spring releasably compressed by an activation arrangement, and wherein when upon activating the activation arrangement the drive spring may be released such that it decompresses to provide the driving force for acting on the cord
Implementation Method 2
Adjacent plunger elements in the plurality of plunger elements may be connected by a plurality of elastic elements, the plurality of elastic elements being arranged to stretch as the plunger elements become aligned along their axes
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
An auto-injector (10) for delivering a liquid medicament comprising: a housing (11) arranged to contain a syringe and a piston for sealing the syringe and displacing the medicament, the housing having a distal end and a proximal end intended to be applied against an injection site, wherein the syringe comprises: a plurality of plunger elements (16) arranged along a length of the syringe between the distal end of the housing and the piston, each of the plurality of plunger elements having a longitudinal axis; and a cord (19) arranged to connect the plurality of plunger elements, wherein the plunger elements are configured to become aligned along their axes to push the piston towards the proximal end to displace the medicament when the cord is acted on by a driving force.