Drug Delivery Cap Orientation and Snap Feature Design
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Solution Overview
Problem
Existing drug delivery devices lack a mechanism to ensure the cap is attached to the housing in a specific orientation, leading to potential misalignment and incorrect assembly.
Innovation Solution
The cap features a combination of orientation features at a rigid part and snap features at a less rigid part, with an offset along the longitudinal axis, to ensure correct attachment by preventing assembly in incorrect orientations through a system of ribs and grooves, and snap features that require elastic deformation for engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If all orientation features are located at a flexible part of the cap, then the cap can be easily deformed to allow assembly, but the cap may be attachable to the housing in wrong orientations
Solution Approach 1:
The cap is divided into rigid and flexible parts with different functions. Orientation features are placed at rigid parts to ensure correct orientation, while snap features are placed at flexible parts to enable easy assembly through elastic deformation.
Solution Approach 2:
Different parts of the cap have different rigidity properties. The closed end is made rigid to maintain orientation features, while the open end is made flexible to accommodate snap features that require deformation for assembly.
2Reliability
If snap features are located at a rigid part of the cap, then the attachment is secure, but the cap cannot be easily deformed for engagement
Solution Approach 1:
The cap has localized flexibility at the open end where snap features are positioned, allowing elastic deformation for engagement. The closed end remains rigid to maintain orientation features and overall structural stability.
Solution Approach 2:
The cap transitions from a static rigid structure to a dynamic structure with controlled flexibility. The flexible part allows temporary deformation during assembly, then returns to its original shape to secure the snap features.
3Ease of operation
If the cap can be easily deformed for assembly, then the engagement is easy, but the orientation features may bump over the mating orientation features of the housing
Solution Approach 1:
The cap is segmented into rigid and flexible zones. Orientation features are exclusively placed in rigid zones that cannot deform, ensuring precise alignment with mating features on the housing during assembly.
Solution Approach 2:
The rigid part of the cap maintains its shape and orientation features during assembly, preventing any bumping or misalignment, while only the flexible part with snap features undergoes deformation.
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
This design ensures reliable and secure attachment of the cap in the correct orientation, preventing misassembly and ensuring user visibility of critical information, such as drug type and filling status, while protecting the cartridge or needle unit.
Implementation Method 1
a certain elastic deformability of the cap may be required
Data Source
Figure 1~2B
Figure 3~4B
Figure 5
AI summary
A drug delivery device (1) comprises a housing (2) and a cap (3) attachable onto the housing (2). The cap (3) comprises one or more snap features (33) to attach the cap (3) onto the housing (2) and one or more orientation features (34) to define the orientation of the cap (3) relative to the housing (2). At least one of the orientation features (34) is located at a rigid part of the cap (3) and at least one of the snap features (34) is located at a less rigid part of the cap (3).