Cartridge Retainer With Deformable Tabs for Injection Devices
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Solution Overview
Problem
Existing cartridge retainers for injection devices face challenges in securely holding cartridges due to variability in dimensions and materials, leading to potential fluid loss during needle insertion, especially with changes in septum thickness and ISO specifications, which complicates accurate dosage delivery and increases the need for improved retention mechanisms.
Innovation Solution
A cartridge retainer design featuring a sleeve with radially extending tabs and axially deformable members, including projections and ribs, that securely sandwich the cap between them, preventing cartridge movement during needle insertion and ensuring precise dosage delivery by maintaining the cartridge's position relative to the retainer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid retention mechanism is used to securely hold the cartridge, then the cartridge position stability is improved, but the adaptability to varying cartridge dimensions and materials deteriorates
Solution Approach 1:
The retainer employs deformable members (such as elastomeric O-rings or springs) that can dynamically adjust their position and shape to accommodate varying cartridge dimensions. These members deform elastically under compression from the cartridge cap, allowing the retainer to adapt to different cartridge sizes while maintaining secure retention. This dynamic deformation resolves the contradiction by providing both stability through the deformable members' elastic recovery and adaptability through their variable deformation states.
Solution Approach 2:
The retainer utilizes changes in the physical state and dimensional parameters of the deformable members to accommodate different cartridge specifications. The deformable members change their compression level, shape, and contact pressure based on the cartridge dimensions, enabling the same retainer structure to work with varying cartridge materials and sizes. This parameter change approach allows the retainer to maintain optimal retention force across different cartridge types without requiring multiple specialized designs.
2Loss of substance
If the cartridge is securely retained to prevent movement, then fluid loss is reduced, but the complexity of the retention mechanism increases
Solution Approach 1:
The deformable members are designed to automatically adjust and self-regulate the retention force based on the cartridge's position and dimensions. As the cartridge is inserted, the deformable members naturally compress and deform to engage with the cartridge cap, creating a self-adjusting retention mechanism that requires no additional actuators or complex control systems. This self-service approach reduces fluid loss through reliable retention while keeping the overall mechanism simple and passive.
Solution Approach 2:
The retainer employs flexible deformable members (such as elastomeric O-rings or thin-walled deformable ribs) that can bend and deform to accommodate the cartridge cap. These flexible elements provide effective retention through their elasticity and ability to conform to the cartridge geometry, preventing fluid loss without requiring rigid complex structures. The flexible members simplify the overall design compared to rigid multi-component retention systems while maintaining effective sealing and position stability.
3Adaptability or versatility
If deformable members are used to accommodate varying cartridge dimensions, then the adaptability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The deformable members are designed with specific material properties (elastic modulus, durometer) and geometric parameters that allow them to deform within predictable ranges. By selecting materials and dimensions that provide sufficient deformation capacity, the design accommodates varying cartridge dimensions without requiring extremely tight manufacturing tolerances on the deformable members themselves. The material's inherent variability and the designed deformation range absorb manufacturing variations, reducing precision requirements while maintaining adaptability.
Solution Approach 2:
The retainer may incorporate composite construction combining rigid and flexible materials, where the deformable members are made of elastomeric materials or composite structures that provide both durability and flexibility. This composite approach allows the deformable members to accommodate a range of cartridge dimensions through material elasticity rather than requiring precise dimensional control during manufacturing. The combination of rigid structural elements and flexible deformable members achieves adaptability while managing manufacturing precision requirements through material selection.
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 design effectively reduces fluid loss by immobilizing the cartridge, allowing for accurate and consistent delivery of smaller dosages without the need for priming, even on the first injection, and accommodates varying cartridge dimensions and materials.
Implementation Method 1
one or more deformable members extending axially from the distal end of the sleeve toward the one or more tabs and configured to deform in a longitudinal direction toward the distal end
Implementation Method 2
the one or more tabs are configured to radially deflect away from the longitudinal axis during insertion of a cap of a cartridge and at least partially return to an initial position to abut a bottom surface of the cap in an inserted position
Data Source
AI summary
A cartridge retainer comprises a sleeve having a distal end a proximal end and a longitudinal axis extending between the distal end and the proximal end. One or more tabs extend radially from the sleeve toward the longitudinal axis and are configured to radially deflect away from the longitudinal axis. One or more deformable members extend axially from the distal end of the sleeve toward the one or more tabs and are configured to deform in a longitudinal direction toward the distal end.