Bistable Membrane Dispensing Closure for Sterile Needle Piercing
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Solution Overview
Problem
Existing drug dispensing devices with thin, deformable membranes face manufacturing challenges due to precise positioning requirements and unreliable deformation, making them difficult to assemble and maintain sterility during product distribution.
Innovation Solution
A bistable membrane design that snaps from a first stable position to a second stable position, ensuring reproducible deformation and sterility, using a membrane-fixing ring on a standard reservoir without additional mechanisms, and a needle that pierces the membrane only in the second position, simplifying assembly and maintaining sterility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thin membrane (0.1 to 0.2 mm) is used to seal the reservoir, then the membrane can be deformed to contact the needle, but the manufacturing and assembly become difficult requiring great care and precise positioning
Solution Approach 1:
The invention changes the membrane thickness parameter from thin (0.1-0.2mm) to thick (several mm), fundamentally altering the membrane's mechanical properties. This parameter change eliminates the need for precise positioning while maintaining the ability to deform and contact the needle for product dispensing.
Solution Approach 2:
Instead of deforming a thin membrane to make contact with the needle, the invention inverts the approach by using a thick membrane that naturally protrudes or can be easily deformed without requiring high precision. The problem is solved by reversing the conventional wisdom about membrane thickness and deformation mechanics.
2Reliability
If a thin membrane is used, then it can deform under differential pressure, but the deformation is difficult to achieve reproducibly
Solution Approach 1:
By changing the membrane thickness parameter to several mm, the invention achieves reproducible deformation without requiring complex structural designs. The thicker membrane provides consistent mechanical behavior under differential pressure, eliminating reproducibility issues inherent in thin membrane systems.
3Reliability
If additional membrane-fixing mechanisms are added to the reservoir, then the membrane can be secured, but the device complexity increases
Solution Approach 1:
The invention extracts the membrane-fixing function from complex mechanical mechanisms and integrates it directly into the reservoir structure itself. The reservoir is designed with features that inherently secure the thick membrane, eliminating the need for separate fixing components and reducing overall device complexity.
Solution Approach 2:
The reservoir structure and membrane-fixing function are merged into a single integrated component. The reservoir design incorporates the fixation capability, so that the same structural element that holds the reservoir also secures the membrane, reducing the number of parts and simplifying assembly.
4Ease of operation
If the needle is positioned close to the membrane, then the membrane can be pierced, but maintaining sterility becomes difficult
Solution Approach 1:
The thick membrane (several mm) acts as an extended barrier that maintains the sterile seal even when the needle is positioned relatively close. The membrane's thickness provides a buffer zone that preserves sterility while still allowing reliable piercing when needed for product dispensing.
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 enhances reproducibility and simplifies assembly while maintaining sterility from assembly to product distribution, using a bistable membrane that snaps into place and a needle that contacts the product only during dispensing, ensuring reliable and economical operation.
Implementation Method 1
the membrane being bistable in that it is configured to switch from a first stable position, in which the membrane is domed in a first direction so that it protrudes inside the reservoir and closes the reservoir, to a second stable position, in which the membrane is domed in a second direction opposite to the first direction so as to be pierced by a needle disposed on the outer side of the membrane
Data Source
Figure 1~3
Figure 4~5
AI summary
The invention relates to a device (1) for dispensing a product, comprising: - a reservoir (3) of product (P) provided with a neck (9) delimiting an opening (11), - a membrane (5) closing the opening (11) and thus having an internal side (13) oriented towards the reservoir (3) and an external side (15) away from the internal side (13), - a ring (7) for fixing the membrane (5) to the neck (9), the membrane (5) being bistable in that it is configured to flip from a first stable position, in which the membrane (5) bulges in a first direction such that it protrudes into the reservoir (3) and closes off the reservoir (3), into a second stable position, in which the membrane (5) bulges in a second direction opposite to the first direction so as to be pierced by a needle (8) disposed on the external side (15) of the membrane (5).