Pen Needle Protector Element and Spring Mechanism
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Solution Overview
Problem
Traditional pen needles are difficult to use due to the presence of helical springs that oppose the cannula's emergence, making injections painful and complicated, and they can be reused or pose safety risks due to their complex construction and visibility of the cannula, leading to anxiety and potential infections.
Innovation Solution
A pen needle design featuring a movable protector element with protuberances that minimizes the force required for injection and automatically covers the cannula after use, using a preassembled cylindrical container with a helical spring to ensure safe and easy operation, hiding the cannula from view and preventing reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a helical spring is used to automatically cover the cannula after use, then safety and automatic protection are improved, but the injection operation becomes difficult and painful due to the spring opposing the cannula's emergence
Solution Approach 1:
The protection system is divided into two distinct phases: a pre-use protector element that covers the cannula and a post-use spring mechanism that activates only after injection. This segmentation allows the spring to provide automatic protection without opposing the cannula's emergence during injection, as the spring is compressed during injection and only expands to protect after use.
Solution Approach 2:
The protector element is positioned in advance to cover the cannula before use, and the spring is pre-compressed during the injection process. This preliminary action ensures that the spring is ready to provide automatic protection after injection without interfering with the injection operation itself.
2Device complexity
If the cannula is visible to the patient before use, then the device structure is simple, but patient anxiety and fear increase leading to difficult injection
Solution Approach 1:
A protector element is introduced as an intermediary component between the cannula and the patient's view. This element covers the cannula before use, hiding it from the patient's sight, and only moves away during injection to allow the cannula to emerge. This intermediary solution reduces patient anxiety without significantly complicating the overall device structure.
3Reliability
If the pen needle is designed for once-only use, then safety against infection is improved, but the risk of accidental reuse and associated infections increases
Solution Approach 1:
The pen needle is designed with an automatic protection mechanism that activates after use to securely cover and protect the cannula. This self-service feature ensures that even if a patient attempts to reuse the device, the protected cannula cannot be inserted again, thereby preventing infection risks associated with reuse while maintaining the intended once-only use.
4Reliability
If a complex spring mechanism is added to protect the cannula, then safety is improved, but the device construction becomes more complicated
Solution Approach 1:
The protector element and the spring mechanism are merged into a single integrated assembly that functions as one unit. The spring is positioned within the protector element housing, and both components work together seamlessly to provide automatic protection. This merging approach reduces the number of separate parts and simplifies the overall construction while maintaining effective cannula protection.
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
The design reduces patient anxiety and pain during injections, ensures safe operation by hiding the cannula, and prevents accidental reuse or exposure, providing a simpler and safer pen needle solution.
Implementation Method 1
a helical spring present in a container element, said spring acting on said protector element to move the latter to a position such as to cover the cannula
Data Source
Figure 1
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AI summary
A pen needle to be connected to a container or pen with which a vial of medicament is associated, said needle (1) comprising: - a metal cannula (5) provided with two points (25, 26), one at each end, one known as the patient point (25), and one known as the vial point (26); - a needle carrier (3), to be connected to said pen; - a container (2), the purpose of which is to receive the entire pen needle (1) prior to use; - a cover element (6), connected to the needle carrier (3) and positioned about the cannula (5); - a protector element (20), movable within the cover element (6) and arranged to emerge from this latter so as to cover and protect the patient point (25) of the cannula after its extraction from the patient on termination of the injection; - an elastic element (36) arranged to press on the protector element (20) such as to enable it to move on termination of the injection in order to cover the first point (25) of the cannula (5); - locking means (47) are provided for the elastic element (36) to prevent its action on the protector element (20), at least until a moment subsequent to the commencement of introduction of the cannula (5) into the epidermis, said locking means (47) being removable after the moment in which this introduction commenced.