Injection Device Cap Needle Piercing Mechanism
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Solution Overview
Problem
Conventional injection devices pose challenges for users, particularly the elderly and children, due to the need for manual force and dexterity to administer injections, and they often have integrated needles that increase the risk of needle stick injuries.
Innovation Solution
An improved injection device design featuring a cartridge holder, a hollow injection needle with a piercing mechanism, and a cap that moves to establish fluid communication between the cartridge and needle, allowing for separate storage of the needle to prevent drug-needle reactions, with a spring for easy operation and audible/tactile feedback for engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the needle is integrated with the syringe, then the device structure is simplified, but the risk of needle stick injuries increases
Solution Approach 1:
The injection device is divided into separate functional components: a syringe body, a detachable needle assembly, and a cap. The needle can be attached to the syringe immediately before use and removed afterward, separating the injection function from the storage and disposal phases.
Solution Approach 2:
The needle is extracted from the integrated syringe structure and made detachable. This allows the needle to be removed from the syringe body after injection, eliminating the need for users to handle integrated needle-syringe combinations and reducing needle stick injury risks during disposal.
2Device complexity
If manual force is required to drive the medicament, then the device structure is simplified, but the ease of operation deteriorates for elderly or children
Solution Approach 1:
The device incorporates a spring mechanism that automatically generates the force needed to drive the plunger and administer the injection. When the cap is removed, the spring is released and automatically pushes the plunger forward, eliminating the need for users to manually apply force.
Solution Approach 2:
A spring mechanism acts as an intermediary between the user's action of removing the cap and the actual injection process. The spring stores energy during assembly and releases it automatically to drive the plunger, mediating the transition from a simple cap-removal action to a controlled injection.
3Device complexity
If the button/plunger must be continuously pressed, then the device structure is simplified, but the reliability of dose delivery deteriorates
Solution Approach 1:
The spring mechanism automatically performs the function of continuously pressing the plunger without user intervention. Once activated by cap removal, the spring self-regulates the plunger movement to deliver the complete prescribed dose, eliminating the risk of premature release or incomplete injection.
Solution Approach 2:
The device incorporates a mechanism that provides feedback to ensure complete dose delivery. The spring is pre-loaded with a specific force and travel distance that corresponds to the required dose, and the system automatically maintains pressure until the entire medicament is administered, preventing under-dosing.
4Object-affected harmful factors
If the needle is stored separately from the cartridge, then the risk of drug-needle reactions is reduced, but the device complexity increases
Solution Approach 1:
The device is segmented into a cartridge holder containing the drug cartridge and a separate needle assembly that can be attached to the holder. This physical separation prevents unwanted interactions between the drug and needle materials during storage and transport.
Solution Approach 2:
The needle is prepared and stored separately in a sterile state, and the cartridge is prepared separately in a sealed state. Both components are ready for use but remain isolated from each other until the moment of injection, preventing premature drug-needle contact while maintaining readiness for immediate administration.
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 device simplifies the injection process, reduces the risk of needle stick injuries by storing the needle separately, and provides a user-friendly mechanism that does not require excessive manual force or dexterity, making it accessible for a broader range of users.
Implementation Method 1
A spring is arranged for biasing the cap in the distal direction relative to the cartridge holder
Implementation Method 2
The cap comprises one or more internal longitudinal ribs adapted to protrude through the lateral apertures to frictionally clamp and fix the drug cartridge in an axial position within the cartridge holder
Data Source
AI summary
Described is an injection device (1) for administering a drug, the injection device (1) comprising a cartridge holder (2) adapted to receive a drug cartridge (3), a hollow injection needle (6) having a proximal tip (6.2) adapted to pierce a septum (4) of the cartridge (3) so as to establish a fluid communication between the cartridge (3) and the needle (6), and a cap (7) arrangeable over the cartridge holder (2) in a manner to cover the needle (6). In an initial state the cartridge (3) is arranged within the cartridge holder (2) with the septum (4) axially spaced from the proximal tip (6.2) of the needle (6). The cap (7) is adapted to move the needle (6) relative to the septum (4) for piercing it on movement of the cap (7) relative to the cartridge holder (2).