Injection Device Flexible Segment Retention for Blood Suction Control
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Solution Overview
Problem
Existing injection devices face challenges in handling the needle during removal due to the rebound phenomenon and subsequent blood suction, leading to fibrin deposition and flow rate reduction in implantable chambers, requiring frequent replacement.
Innovation Solution
The injection device incorporates means for retaining a flexible segment perpendicular to the needle, with a cam surface and bearing surface to generate over-pressure in the injection conduit during extraction, and a retaining channel to facilitate easier handling and prevent blood ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the needle is removed by pulling the holder directly, then the extraction force is significant, but the risk of rebound sticking is high
Solution Approach 1:
A push element is introduced as an intermediary between the practitioner's hand and the needle holder. This push element transfers the extraction force while maintaining control, reducing the direct pulling force on the holder and minimizing rebound sticking risk.
Solution Approach 2:
The needle is extracted from the holder by pushing the holder relative to the needle, rather than pulling the needle directly. This reverses the extraction mechanism to reduce rebound effects.
2Object-affected harmful factors
If over-pressure is generated in the injection conduit during extraction, then blood suction is reduced, but the device complexity increases
Solution Approach 1:
The injection conduit includes a flexible segment that dynamically changes its configuration during needle extraction. As the push element moves, the flexible segment bends and compresses, automatically generating over-pressure to prevent blood suction without requiring additional active components.
Solution Approach 2:
The flexible segment self-generates over-pressure through its own deformation during the extraction process, eliminating the need for external pumps or valves to prevent blood suction.
3Ease of operation
If the flexible segment is retained perpendicular to the needle, then handling during removal is improved, but the device structure becomes more complex
Solution Approach 1:
The flexible segment is constrained to bend in a specific dimension perpendicular to the needle axis. This controlled deformation in one dimension simplifies the retaining means while improving handling during extraction.
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 enhances needle handling and reduces blood suction, minimizing fibrin deposition and extending the lifespan of implantable chambers by maintaining a stable flow rate.
Implementation Method 1
compress the aforementioned flexible segment between the cam surface and the supporting surface radially and perpendicularly to the needle as the push element slides towards the needle extraction position
Implementation Method 2
a flexible segment formed in the injection conduit
Data Source
AI summary
The invention relates to a device (10) for injecting a liquid into a body, in particular that of a patient, of the type that comprises: a base (20) bearing an injection needle (22) that is to be inserted into the body; an injection conduit (24) connected to the needle (22); means (26) for extracting the needle (22) from the patient, including a plunger (52) mounted such that it can slide in relation to the base (20) between a needle (22) use position and a needle (22) extraction position; and means (28) for generating excess pressure in the injection conduit (24) as the needle (22) is extracted, including a flexible section (53) formed in the injection conduit (24), a cam surface (54) rigidly connected to the plunger (52), and a supporting surface rigidly connected to the base (20), in order to compress said flexible section (53) between the cam surface (54) and the supporting surface radially and perpendicularly to the needle (22) as the plunger (52) slides towards the needle (22) extraction position. The invention is characterized in that it includes means (56) for retaining the flexible section (53) substantially perpendicular to the needle (22).