Discharge Device Return Lock Mechanism for Overdose Prevention
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Solution Overview
Problem
Existing discharge devices for pharmaceutical media lack effective mechanisms to prevent improper overdosing, allowing users to discharge excessive amounts of liquid through partial stroke movements, which can lead to misuse.
Innovation Solution
A discharge device with a return lock mechanism that prevents immediate return of the actuating element to its starting position unless the actuator reaches the end position, ensuring the blocking position is established, and a pump design where the pump chamber is only filled during a defined return stroke, preventing continuous drawing of medium until the intermediate filling position is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking member is provided to prevent discharge, then overdose prevention is improved, but users can still perform partial stroke movements to discharge excessive amounts
Solution Approach 1:
The return lock mechanism performs preliminary anti-action by preventing the actuating element from returning to the starting position until the blocking position is reached. This preliminary constraint stops users from performing partial stroke movements that would otherwise allow excessive discharge, thereby strengthening overdose prevention while maintaining operational control.
Solution Approach 2:
The system dynamically transitions between locked and unlocked states based on the position of the actuating element. The return lock is engaged during normal operation to prevent partial strokes, but automatically disengages when the blocking position is reached, allowing the cycle to reset. This dynamic behavior resolves the contradiction by making the restriction conditional rather than absolute.
2Productivity
If the pump chamber is filled continuously during return stroke, then discharge efficiency is improved, but misuse can occur through repeated partial actuations
Solution Approach 1:
The pump chamber is pre-filled during the return stroke before the discharge stroke begins. This preliminary action ensures that the pump is ready for efficient discharge while the return lock simultaneously prevents the actuating element from returning, blocking any attempt at partial actuation and misuse.
Solution Approach 2:
The pump chamber filling occurs continuously during the return stroke, maintaining uninterrupted preparation for discharge. This continuous useful action is paired with the continuous engagement of the return lock, which prevents any interruption or partial cycling that would lead to misuse, thereby resolving the contradiction between efficiency and reliability.
3Speed
If the actuating element can return immediately to starting position, then operational speed is improved, but the blocking position cannot be established
Solution Approach 1:
The actuating element must first reach the blocking position and establish it before the return lock disengages, allowing the element to return to the starting position. This preliminary establishment of the blocking position ensures reliability, while the subsequent rapid return enables high operational speed in the next cycle.
Solution Approach 2:
The system operates in periodic cycles where the actuating element is constrained to reach and establish the blocking position, then rapidly returns to the starting position. This periodic rhythm alternates between the reliability-critical phase (establishing blocking position) and the speed-critical phase (rapid return), resolving the contradiction through temporal separation of functions.
Data Source
Figure 1a~1b
Figure 1c~1f
Figure 2a~2c
AI summary
The device has an operating member (88) manually movable relative to a housing and transferred from an unoperated starting position in an operating direction (1a) into an operated end position. A locking member is movable between a locked position and a release position. A spring e.g. plastic helical spring, applies a force to the locking member in the direction of the release position. The operating member and the locking member are operatively coupled together such that a stroke movement and a return stroke movement of the operating member are brought by a transmission mechanism.