Radial Coupling Drive Mechanism for Drug Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drug delivery devices lack an efficient and safe mechanism to prevent rearward movement of the plunger and ensure precise control over substance dispensing, leading to potential misuse or incorrect dosing.
Innovation Solution
A drive mechanism for a drug delivery device featuring a piston rod and drive member that can move radially between two positions, with a coupling element preventing proximal movement of the piston rod and allowing incremental, unidirectional movement, ensuring safe and controlled dispensing of medication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one way mechanism with diametrically opposed pawls is used to prevent rearward movement of the plunger, then the plunger movement is controlled, but the device complexity increases and the mechanism becomes independent from the housing and plunger requiring additional components
Solution Approach 1:
The coupling element is integrated into the housing structure, merging the prevention function with the existing housing component. This eliminates the need for separate independent mechanisms and reduces overall device complexity while maintaining reliable plunger movement control through the coupling features that engage with the piston rod feature.
2Ease of operation
If the drive member is allowed to move freely in the axial direction for setting substance amount, then the ease of operation is improved, but the risk of misuse and incorrect dosing increases
Solution Approach 1:
The drive member's axial movement is made dynamic and conditional through the coupling element. The drive member can move axially to set the substance amount, but this movement is controlled and limited by the coupling features that engage with the piston rod feature. This dynamic control allows operational flexibility while preventing misuse by restricting the movement range and direction.
3Object-affected harmful factors
If the piston rod is prevented from proximal movement by the coupling element, then the safety against misuse is improved, but the device complexity increases due to additional coupling features
Solution Approach 1:
The coupling element serves multiple functions: it prevents proximal movement of the piston rod to prevent misuse, and simultaneously provides the necessary engagement features for controlled distal movement during normal operation. By integrating these functions into a single multi-functional component, the overall device complexity is minimized while achieving effective misuse prevention.
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
A drive mechanism for a delivery device is presented. The drive mechanism comprises a housing (24) and a piston rod (6) having a longitudinal axis (x) and a piston rod feature (17). The drive mechanism further comprises a drive member (1) being movable with respect to the housing (24). The drive member (1) comprises a drive feature (15). The drive feature (15) is selectively engageable with the piston rod feature (17) by the radial displacement of the drive member (1) with respect to the piston rod (6). When the drive member (1) is in the first position, the drive member (1) is disengaged from the piston rod (6), and when the drive member (1) is in the second position, the drive feature (15) is engaged with the piston rod feature (17). When the drive member (1) moves distally with respect to the housing (24), said distal movement is transferred to the piston rod (6) such that the piston rod (6) moves distally with respect to the housing (24).