Autoinjector Cap Interlock Mechanism for Secure Connection
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Solution Overview
Problem
Conventional autoinjector caps have a weak and non-visible connection mechanism, which can lead to accidental removal and hygiene risks due to dirt or bacteria trapping.
Innovation Solution
The autoinjector assembly features a secure connecting arrangement with a bulb-shaped projection on the main body and a corresponding cut-out on the cap, allowing interlocking that prevents accidental removal and provides a visible connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional dimples and recesses are used for connecting the cap to the main body, then the connection mechanism is simple to manufacture, but the connection strength is weak and the connection is not visible
Solution Approach 1:
The invention inverts the conventional approach by making the cap the male element (projection) and the main body the female element (recess), rather than the conventional dimples-on-cap design. This inversion allows the projection to be visible on the outer surface of the cap, providing both visual confirmation of engagement and a stronger mechanical connection through the neck-to-locating portion interlock
Solution Approach 2:
The connecting arrangement transitions from a two-dimensional surface feature (dimples on the inner surface) to a three-dimensional protruding structure (projection with neck and head portions) that extends from the outer surface of the cap, adding dimensional complexity that enhances both visibility and connection strength
2Loss of information
If dimples are placed on the inner surface of the cap, then the connecting arrangement is simple in structure, but the connection status is not visible to the user
Solution Approach 1:
The invention inverts the conventional approach by making the cap the male element (projection) and the main body the female element (recess), rather than the conventional dimples-on-cap design. This inversion allows the projection to be visible on the outer surface of the cap, providing both visual confirmation of engagement and a stronger mechanical connection through the neck-to-locating portion interlock
3Object-affected harmful factors
If conventional dimple connections are used, then the manufacturing process is simple, but dirt or bacteria can be trapped leading to hygiene risks
Solution Approach 1:
The invention extracts the connection features from the inner surface of the cap and relocates them to the outer surface. The projection extends outward from the cap's external surface, eliminating the creation of internal cavities or recesses where contaminants could accumulate, thereby improving hygiene while maintaining manufacturing simplicity
Solution Approach 2:
The invention inverts the conventional approach by making the cap the male element (projection) and the main body the female element (recess), rather than the conventional dimples-on-cap design. This inversion allows the projection to be visible on the outer surface of the cap, providing both visual confirmation of engagement and a stronger mechanical connection through the neck-to-locating portion interlock
Data Source
Figure 1
AI summary
An injector assembly (100) includes a main body (102) having a first connecting arrangement, and a cap (104) having a second connecting arrangement for, in use, releasably connecting the cap to the first connecting arrangement of the main body. The first or the second connecting arrangement (120) includes an open neck portion (122) leading to a locating portion (124), at least part of the locating portion having a maximum width (120A) greater than a maximum width (120B) of the open neck portion. The second or the first connecting arrangement (108), respectively, includes a head portion (109) having a maximum width (108A) greater than the maximum width of the open neck portion.