Liquid Administration Tool Cover Member Locking Mechanism
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Solution Overview
Problem
Existing liquid administration tools cannot restart drug solution administration after the needle tube is pulled out from the body, as the cover member becomes locked in a position that prevents re-exposure of the needle tip, preventing further administration.
Innovation Solution
A liquid administration tool with a cover member that includes a biasing member and a movement amount restriction unit, allowing the cover member to be retracted and locked in a position that exposes the needle tip for re-administration, enabling the tool to resume liquid delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the cover member is moved forwards to cover the needle tube after administration, then the needle tube is covered and the injection device can be discarded safely, but the cover member is blocked from moving backwards again and the needle tip cannot be exposed for re-administration
Solution Approach 1:
The locking unit is designed to dynamically switch between locked and unlocked states based on the operational phase. During administration, the locking unit remains unlocked allowing cover movement. After administration completion, the locking unit engages to prevent accidental exposure. The system transitions from a static locked state to a dynamic state where unlocking is only possible through the specific operation of advancing the plunger, thus resolving the contradiction between safety and re-administration capability
Solution Approach 2:
The system changes the operational parameter of the cover member from free movement during administration to restricted movement after administration. The locking unit detects the completion of administration through the plunger advancement and automatically changes the movement restriction parameter, allowing the cover to be locked in the covering position while maintaining the capability to unlock through proper operation sequence
2Reliability
If the cover member is prevented from moving backwards after covering the needle tube, then the needle tip remains covered for safety, but administration cannot be re-started if temporarily interrupted
Solution Approach 1:
The locking unit receives feedback from the plunger position and operation status to control the locking mechanism. When the plunger is advanced to complete administration, this feedback triggers the locking unit to engage and prevent cover retraction. If administration is interrupted before completion, the feedback indicates incomplete operation and keeps the locking unit disengaged, allowing cover movement and re-administration. This feedback-based control resolves the contradiction between maintaining covered state and enabling resume capability
3Object-affected harmful factors
If the cover member is locked in the covering position after use, then accidental needle exposure is prevented, but the device cannot accommodate temporary interruption during administration
Solution Approach 1:
The locking unit is designed to engage automatically after administration completion, performing the safety action of covering the needle in advance before any accidental exposure could occur. The system prepares the locked state as the default after use, while the preliminary design of the unlock mechanism through plunger advancement allows flexibility when needed. This preliminary safety action with built-in exception handling resolves the contradiction between prevention and flexibility
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
Enables the resumption of liquid administration even after temporary interruption, ensuring complete delivery of the desired amount of drug solution while maintaining safety by preventing accidental needle exposure post-use.
Implementation Method 1
a biasing member configured to bias the cover member in the direction toward the distal end
Data Source
AI summary
A liquid administration tool includes a structure including a tubular body in which liquid is fillable, the tubular body having a bottom portion at a distal end and, an opening portion at a proximal end, and a needle tube positioned at a distal portion of the tubular body, the needle tube having a needle tip at a distal end thereof, and the needle tube being communicable at a proximal end thereof with an inside of the tubular body; an operation member having a pusher; a cover member; a biasing member configured to bias the cover member in the distal direction; a locking unit configured to restrict the movement of the cover member; and a movement amount restriction unit configured to restrict the movement amount of the cover member.