Tamper-proof injector with segmented piston and undercut seal
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Solution Overview
Problem
Existing injectors lack comprehensive protection against tampering, allowing manipulation of the piston area and potential substitution of the medicament, which compromises the integrity of the dispensed liquid or paste.
Innovation Solution
The injector design incorporates a housing part with an undercut and a piston body projection that prevents the piston from being pulled out, combined with a detachable ram and piston connection that ensures the piston remains in the housing, providing a tamper-evident and tamper-proof seal by engaging with the undercut and using a bead and groove mechanism for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the piston body is made detachable with a plunger and piston connected by a breaking point, then ease of operation is improved, but reliability deteriorates because the piston can be pulled out and tampering becomes possible
Solution Approach 1:
The piston body is divided into two segments: a plunger and a piston, connected by a predetermined breaking point. This segmentation allows the plunger to be removed for refilling while the piston remains in the housing to maintain the seal and prevent tampering with the medicament.
Solution Approach 2:
The piston acts as an intermediary element between the plunger and the medicament. It remains permanently engaged with the housing part via the undercut, serving as a mediator that maintains the seal and prevents direct access to the medicament while allowing the plunger to be removed and reattached.
2Ease of operation
If the cap part and connecting part are detachably connected by a breakaway edge, then ease of operation is improved, but reliability deteriorates because only the cap is protected from tampering
Solution Approach 1:
The closure cap is segmented into a cap part and a connecting part that can be detachably connected. This allows the cap to be removed for access while the connecting part remains with the housing, maintaining the seal.
Solution Approach 2:
The piston body and closure cap are combined to form an integrated sealing system. Both the piston (via undercut engagement) and the closure cap (via breakaway edge) work together to provide comprehensive tamper protection, merging two separate protection mechanisms into a unified system.
3Ease of manufacture
If the piston body is completely removable from the housing part, then ease of manufacture is improved, but reliability deteriorates because substitution of medicament becomes possible
Solution Approach 1:
The piston body is segmented into a plunger and a piston, allowing the plunger to be completely removed for refilling while the piston remains engaged with the housing. This segmentation enables easy manufacture and refilling while maintaining medicament integrity through the permanent piston seal.
Solution Approach 2:
The plunger is extracted from the piston body through the predetermined breaking point, allowing it to be completely removed for refilling. The piston itself remains in place, extracting only the necessary component for access while maintaining the sealing function.
Data Source
Figure 1a~3
Figure 4~7
AI summary
The injector has a housing part (1), piston body (2) and a locking cap (3) with a cap part for locking an opening of the injector and with a connection part for connecting the locking cap with the injector. The cap part and the connection part are detachably connected through a tearing edge. The housing part is provided with an undercut, and the piston body is provided with a projection, where the undercut and the projection are co-ordinated. The piston body is single-piece formed, where the piston body has a slide and a piston.