Injection Device Strengthening Sheet with Concave Recesses
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Solution Overview
Problem
Existing injection devices with release liners and strengthening sheets suffer from wrinkles and pleats due to convex bulges on the surface, affecting the visual appearance and creating an impression of a faulty assembly.
Innovation Solution
A medicament delivery device with a release liner reinforced by a strengthening sheet featuring a concave recess near apertures, ensuring the sheet is wrinkle-free and maintains a smooth surface, and includes a sterile barrier foil removal mechanism through apertures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a strengthening sheet is applied on a release liner with convex bulges, then the release liner is strengthened, but wrinkles and pleats occur on the strengthening sheet
Solution Approach 1:
The strengthening sheet is designed with a non-uniform thickness profile, featuring a thinner central region and thicker edge regions. This local variation in quality allows the central thin region to conform to convex bulges on the release liner without creating wrinkles, while the thicker edge regions provide the necessary strengthening effect at the boundaries.
Solution Approach 2:
The invention changes the geometric parameter of the strengthening sheet by creating a recess or depression in the central region, forming a concave shape that accommodates convex bulges on the release liner surface. This parameter modification enables the sheet to adapt to surface irregularities while maintaining structural integrity.
2Shape
If the strengthening sheet is made thinner to reduce wrinkles, then the surface smoothness improves, but the strengthening effect is reduced
Solution Approach 1:
The strengthening sheet employs non-uniform thickness distribution where the central region is thinner for smoothness and the edge regions are thicker for strengthening. This local differentiation resolves the contradiction by providing both smooth surface contact and adequate structural reinforcement in different areas.
Solution Approach 2:
The invention transitions from a uniform two-dimensional sheet to a three-dimensional structure with varying thickness. By adding the thickness dimension as a variable parameter, the sheet can simultaneously achieve smooth surface contact in the center and provide strengthening at the edges, resolving the contradiction between smoothness and strength.
3Strength
If a strengthening sheet is added to the release liner, then the release liner strength is improved, but the device complexity increases
Solution Approach 1:
The release liner system is constructed as a composite structure combining the base release liner material with a strengthening sheet layer. This composite approach provides enhanced strength while maintaining the functional properties of the original release liner, achieving a balance between improved performance and acceptable complexity.
Data Source
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AI summary
The present application relates to an injection device comprising a housing with an adhesive layer on at least one side surface of the housing as well as a release liner (20) at least partially covering the adhesive layer. The release liner comprises a sheet of material with a first surface contacting the adhesive layer, as well as at least one aperture (32) defining a passage through the sheet of material. The release liner is covered by a strengthening sheet (40) adhesively connected to a second surface of the sheet of material and covering the at least one aperture. The strengthening sheet includes at least one area which forms a elongate recess (43) relative to the release liner, oriented towards the at least one aperture.