Cartridge Fixation Using a Deformable Arch for Accurate Dosing
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Solution Overview
Problem
Existing drug delivery devices face issues with holding cartridges relative to the housing, leading to potential damage or displacement due to inconsistent or excessive holding forces, which can be exacerbated by manufacturing tolerances and material relaxation during storage.
Innovation Solution
A deformable member within the housing recess, which deforms elastically and plastically to securely hold the cartridge in place, allowing for predictable and adjustable forces to accommodate cartridges of varying lengths, preventing displacement and ensuring dosing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid holding mechanism is used to securely hold the cartridge, then the cartridge retention strength is improved, but the risk of cartridge damage due to excessive holding force increases
Solution Approach 1:
The holding mechanism utilizes the elastic modulus parameter of the deformable member to provide a compliant holding force. By selecting materials and geometries with appropriate elastic properties, the system achieves strong retention while the material's elasticity prevents excessive force transmission to the cartridge, resolving the contradiction between retention strength and damage risk.
Solution Approach 2:
The deformable member acts as a cushioning element that absorbs and distributes holding forces before they can be transmitted to the cartridge. This beforehand cushioning effect prevents sharp force peaks that could damage the cartridge while maintaining sufficient holding strength through the deformable member's elastic recovery.
2Manufacturing precision
If a spring-based holding mechanism is used to provide consistent holding force, then the cartridge positioning accuracy is improved, but the device complexity increases
Solution Approach 1:
The invention extracts the elastic deformation function from a complex spring-based system and implements it through a simplified deformable member. This removes unnecessary mechanical complexity while retaining the core function of providing consistent, compliant holding force for accurate cartridge positioning.
Solution Approach 2:
The system changes the physical state from rigid spring compression to elastic deformation of a deformable member. This parameter change simplifies the mechanism by eliminating the need for separate spring elements, mounting structures, and adjustment mechanisms, while maintaining positioning accuracy through the material's elastic properties.
3Stability of the object's composition
If the holding force is increased to prevent cartridge displacement during storage, then the cartridge stability is improved, but the risk of cartridge breakage due to material relaxation increases
Solution Approach 1:
The deformable member's elastic modulus and deformation characteristics are optimized to provide stable holding force that compensates for material relaxation during storage. The material's elastic properties allow it to maintain consistent force over time while the compliance prevents force spikes that could cause breakage, resolving the contradiction between stability and structural integrity.
4Adaptability or versatility
If a deformable member is used to accommodate cartridges of varying lengths, then the adaptability is improved, but the holding force consistency decreases
Solution Approach 1:
The deformable member's geometry and material properties are designed so that the elastic deformation occurs within a controlled range that maintains consistent holding force. The member's stiffness and cross-sectional dimensions are optimized to ensure that even with varying deformation amounts for different cartridge lengths, the resulting holding force remains consistent through the elastic recovery mechanism.
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 deformable member provides reliable and precise cartridge retention, preventing damage and ensuring accurate dosing by limiting movement within predefined limits, even with material relaxation, and accommodating manufacturing variations.
Implementation Method 1
the deformable member may be deformable from a non-deformed state or an initial state to a deformed state by a displacement of its distal end. In the deformed state the deformable member may be adapted to limit a movement, such as a proximal movement, of a cartridge
Implementation Method 2
The deformable member may include a first arch between the proximal end and the distal end. In the deformed state, the first arch may be deformed both elastically and plastically.
Data Source
AI summary
A housing for a drug delivery device for administrating a liquid drug from a cartridge includes a recess for accommodating a proximal portion of the cartridge and a deformable member arranged inside the recess. The deformable member includes a proximal end attached to the housing and a distal end movable within the recess. The deformable member is deformable from a non-deformed state to a deformed state by a displacement of the distal end. In the deformed state the deformable member is adapted to limit a movement of a cartridge in the longitudinal direction relative to the housing. The deformable member further includes an arch, and in the deformed state the arch is deformed both elastically and plastically.