Injection Device Bead Sealing Mechanism
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Solution Overview
Problem
Current injection devices face sealing issues and increased complexity due to the need for O-rings to manage the retraction of the sheath and interface, which complicates assembly and increases costs.
Innovation Solution
The use of a triple-bead configuration on the sheath and interface, where two beads form a ring and a third bead frames one, providing lateral contact and efficient sealing without O-rings, reducing surface area and hyperstatic issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If O-rings are used to seal the sheath and interface during retraction, then sealing is achieved, but device complexity and cost increase
Solution Approach 1:
The invention extracts and eliminates the O-ring sealing element from the system. Instead of using a separate O-ring component, the sealing function is integrated directly into the bead structure of the sheath and interface, removing the need for additional sealing parts and simplifying the overall device assembly
Solution Approach 2:
The sealing function is merged with the mechanical retention structure. The beads on the sheath and interface serve dual purposes: providing mechanical retention during retraction and creating the sealing interface, combining two previously separate functions into a single integrated structure
2Reliability
If O-rings are used to seal the sheath and interface, then sealing is achieved, but manufacturing cost increases
Solution Approach 1:
The O-ring component is extracted from the bill of materials, eliminating the need to purchase, inventory, and assemble separate sealing elements, thereby reducing manufacturing costs
Solution Approach 2:
The sealing mechanism transitions from a separate elastomeric component (O-ring) to an integrated geometric feature (beads) formed during the molding process, changing the sealing approach from a separate part to an inherent structural feature that reduces part count and assembly steps
3Ease of operation
If a protrusion fits into a recess for mechanical retention, then retraction is enabled, but sealing effectiveness is poor
Solution Approach 1:
The mechanical retention feature (beads) and sealing interface are merged into a single integrated structure. The same bead protrusions that provide mechanical retention also create the sealing contact surfaces, eliminating the need for separate retention and sealing mechanisms
Solution Approach 2:
The bead structure provides localized contact points that simultaneously achieve mechanical retention and sealing. The curved surface of the beads creates concentrated contact areas that provide both the mechanical interlocking needed for retention and the sealing pressure needed for effective sealing
Data Source
AI summary
An injection device, comprising an interface for mounting on a syringe body, the interface comprising an internal passage delimited by an inner wall, a needle and a sheath for receiving said needle, said sheath comprising an outer wall provided with a contact portion of said sheath in contact with an attachment portion of the inner wall of the interface, wherein the contact portion comprises a first bead and in that the attachment portion comprises a second bead, the first and second beads each forming a ring protruding respectively on the contact portion and the attachment portion, the first bead being in contact with the second bead.