Flexible Container Support Structure to Prevent Plunger Rod Jamming
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Solution Overview
Problem
Existing medicament delivery devices face issues with medicament containers jamming due to variations in dimensions, particularly when the radius of the transition surface between the barrel and flange exceeds design specifications, leading to potential plunger rod jamming and device malfunction.
Innovation Solution
A support structure with flexible elements that accommodate an elongated plunger rod, featuring inward and outward protrusions, ensures secure guidance and minimizes friction by allowing radial and axial flexibility, preventing jamming between the plunger rod and medicament container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If arc-shaped flexible elements are used to prevent medicament container movement, then container stability is improved, but the risk of plunger rod jamming increases when container dimensions vary
Solution Approach 1:
The flexible element is divided into distinct functional zones: a first contact region for engaging the medicament container and a second contact region for engaging the plunger rod. This segmentation allows each region to independently perform its function, preventing the flexible element from simultaneously contacting both components in a way that causes jamming.
Solution Approach 2:
Different regions of the flexible element are designed with different properties: the first contact region has specific geometric features (arc-shaped contact surface) optimized for container engagement, while the second contact region is positioned and shaped to engage the plunger rod only when necessary. This local differentiation ensures appropriate interaction with each component.
2Strength
If flexible elements are made resilient to handle impact forces, then shock absorption is improved, but the complexity of ensuring proper guidance increases
Solution Approach 1:
The flexible element is designed to be resilient and capable of dynamic deformation in response to impact forces. The element can elastically deform to absorb shock while maintaining its ability to provide guidance through its geometric configuration, eliminating the need for separate rigid guidance structures.
Solution Approach 2:
The support structure uses a flexible element with inherent elasticity to provide both shock absorption and guidance functions. The flexible nature of the element allows it to deform under impact while its geometric shape (including the inclined surface) provides automatic guidance without requiring additional rigid components.
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 solution effectively prevents medicament container movement and plunger rod jamming, ensuring smooth operation and dose delivery by maintaining secure contact and low friction, even with varied container dimensions.
Implementation Method 1
The at least one flexible element is flexible in a generally radial direction as well as in a generally axial direction
Implementation Method 2
The contact members will ensure that the flexible elements are securely guided generally radially outwards, both when a plunger rod is provided with the support structure, and also when a medicament container is arranged in contact with the flexible elements. Thus, any risk of jamming action of the flexible elements between the plunger rod and an inner surface of the medicament container is minimised.
Data Source
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AI summary
The present invention relates to a support structure (40) for a medicament container (18), which support structure (40) is arranged to accommodate an elongated plunger rod (32), said support structure (40) comprising at least one flexible element (48) arranged to be moved in contact with, and to exert a force, on a distal end surface of said medicament container (18), wherein said at least one flexible element (48) is provided with a contact member (50) arranged to contact an outer surface of said plunger rod (32) and to be moved out of contact with said plunger rod (32 ) when moved in contact with said medicament container (18).