Injection Device Cap With Pressure Equalization Conduit
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Solution Overview
Problem
Existing injection devices face challenges in allowing easy removal of the cap by patients, especially the elderly or infirm, due to the suction effect created when the cap is removed, which requires excessive force, potentially leading to difficulty in accessing the needle for injection.
Innovation Solution
Incorporating a piercing member that moves from an initial position to a cap removal position, allowing gas ingress into the recess, and a conduit to equalize pressure, reducing the force needed to remove the cap, along with an actuator for simplified operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cap is held onto the body with sufficient force to prevent accidental removal, then needle sterility and safety are ensured, but it becomes difficult for patients (especially elderly or infirm) to intentionally remove the cap
Solution Approach 1:
The piercing member is pre-positioned within the cap but not yet engaged with the body. Upon cap removal, it automatically pierces the body to create the pressure equalization pathway, eliminating the need for the patient to manually create this pathway while maintaining strong initial attachment
Solution Approach 2:
The piercing member acts as an intermediary mechanism that automatically creates a pressure equalization pathway when the cap is removed. This intermediary structure allows the suction effect to be mitigated without requiring the patient to directly manage pressure equalization, thus maintaining both secure attachment and ease of removal
2Reliability
If the cap is held tightly to the body, then the needle remains protected, but excessive force is required to remove the cap due to suction effect
Solution Approach 1:
The piercing member is pre-positioned to automatically engage with the body upon cap removal, creating a pressure equalization pathway before the patient must overcome the full suction effect. This preliminary action reduces the peak force required during cap removal
Solution Approach 2:
The piercing member creates a pneumatic pathway that allows air to enter the recess, equalizing pressure between the interior and exterior of the cap. This pneumatic equalization reduces the suction force that the patient must overcome during cap removal, while the cap remains tightly sealed during storage and transport
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 solution reduces the force required to remove the cap, making it easier for patients to access the needle, particularly beneficial for elderly or infirm individuals, while maintaining the sterility and safety of the needle.
Implementation Method 1
the piercing member punctures the body of the needle shield to fluidly communicate with the recess to allow the ingress of gas into the recess. When the cap is removed, the body of the needle shield moves away from the needle syringe such that pressure in the recess decreases resulting in a suction effect. This suction effect results in air being drawn through the conduit and into the recess to equalise the pressure in the recess.
Implementation Method 2
When the cap is removed, the body of the needle shield moves away from the needle syringe such that pressure in the recess decreases resulting in a suction effect. This suction effect results in air being drawn through the conduit and into the recess to equalise the pressure in the recess.
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
The present invention relates to cap (21) for an injection device (20). The cap (21) comprises a needle shield (22) and a conduit (31). The needle shield (22) comprises a body (24) with a recess (25) for receiving part of a needle syringe (18). The conduit (31) is movable from an initial position, wherein a portion of the body (24) is located between the recess (25) and the conduit (31), to a cap removal position, wherein the conduit (31) extends through said portion of the body (24) to fluidly communicate with the recess (25) to allow the ingress of gas into the recess (25).