Liquid Administration Device with Cover-Linked Restricting Mechanism
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Solution Overview
Problem
Existing liquid administration devices, such as prefilled syringes, face issues with accidental leakage and insufficient administration due to erroneous pressing of the plunger before the needle is punctured, leading to unintended discharge of the liquid preparation.
Innovation Solution
A liquid administration device featuring a cylindrical body, a needle tube with a sharp tip, a sliding gasket, an operation member, a restricting member, and a cover member with a slider and rail system that prevents the pressing operation until the needle is properly exposed, ensuring the liquid is only discharged after the body is punctured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cap is removed and the injection needle is mounted, then the liquid preparation can be administered, but the pressing operation may be performed erroneously before the living body is punctured, causing leakage or insufficient administration
Solution Approach 1:
The cover member is moved to the second position (exposing the needle tip) as a preliminary action before the pressing operation can be performed. The slider part must be in the longitudinal direction rail, which requires the cover to be in the second position, ensuring that the needle is properly positioned before the plunger can press the gasket to discharge the liquid preparation.
Solution Approach 2:
The slider part acts as an intermediary mechanism between the cover member position and the pressing operation. The slider part transitions from the lateral direction rail to the longitudinal direction rail as the cover moves, mediating the connection between cover position and plunger operation capability, thereby preventing erroneous pressing before proper needle positioning.
2Adaptability or versatility
If the pressing operation is allowed at arbitrary timing, then the operation is flexible, but the liquid preparation may leak unintentionally or insufficient amount may be administered
Solution Approach 1:
The device dynamically changes the operational state based on the cover member position. When the cover is in the first position (covering the needle), the pressing operation is restricted. When the cover moves to the second position (exposing the needle), the pressing operation becomes enabled. This dynamic control ensures that the liquid preparation is only administered when the needle is properly positioned, preventing leakage and ensuring accurate dosing while maintaining operational flexibility.
3Reliability
If a restricting member is added to prevent erroneous pressing, then the reliability of operation is improved, but the device complexity increases
Solution Approach 1:
The restricting function is merged with the existing cover member and slider mechanism. The slider part serves dual purposes: it indicates the cover member position and simultaneously restricts the pressing operation when the needle is not properly exposed. This merging approach prevents erroneous operation without adding separate complex restricting mechanisms, maintaining device simplicity while improving reliability.
Data Source
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AI summary
A liquid administration device includes: a cylindrically-shaped cylindrical body configured to be filled with liquid; a needle tube configured to have a tip side needle tip, to be provided at the tip side of the cylindrical body, and to be communicable with the cylindrical body; a gasket configured to be capable of sliding within the cylindrical body; an operation member configured to perform pressing operation to discharge the liquid from the needle tube by pressing the gasket toward the tip direction; a restricting member configured to be capable of restricting the pressing operation; and a cover member configured to be capable of moving to a first position, in which the tip side needle tip is covered, and to a second position, in which the tip side needle tip is exposed, wherein a protrusion part is formed protrudedly on the restricting member, and a groove, into which the protrusion part is inserted, is formed on the operation member, the groove having a longitudinal groove formed along the same direction as an operation direction during the pressing operation, and a lateral groove communicating with the longitudinal groove and formed along the direction perpendicular to the operation direction; when the cover member is in the first position, the protrusion part is positioned in the lateral groove and restricts the pressing operation, and when the cover member moves from the first position to the second position, the protrusion part moves from the lateral groove to the longitudinal groove in conjunction with the movement, thereby the pressing operation is made possible.