Medication Delivery Drive Assembly Impeding Element
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Solution Overview
Problem
Existing medication delivery devices lack a reliable mechanism to prevent unintended movement of the piston rod during the reset process, particularly due to gravitational forces, which can lead to accidental detachment of the receptacle and inefficient reinitialization for subsequent use.
Innovation Solution
A drive assembly with an impeding element that exerts a friction force on the guide member, preventing unhindered rotation and movement of the piston rod during reset, ensuring it returns to the start position with increased resistance, thereby preventing accidental movement and facilitating secure reinitialization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the piston rod is made resettable from end position to start position, then the medication delivery device can be reused, but unintended movement during reset may occur due to gravitational forces
Solution Approach 1:
The impeding element is configured to preemptively counteract gravitational forces that could cause unintended piston rod movement during reset. By applying a resisting force before unintended movement occurs, the system prevents accidental detachment and ensures controlled resetting only when intentionally initiated.
Solution Approach 2:
The impeding element acts as an intermediary between the piston rod and the resetting mechanism. It mediates the reset process by allowing controlled movement when force is applied while blocking unintended movement caused by gravity, thus ensuring reliable operation during device reuse.
2Ease of operation
If the guide member is allowed to rotate freely during reset, then the piston rod can return to start position, but accidental movement and detachment may occur
Solution Approach 1:
The impeding element dynamically adjusts its restraining effect based on the forces applied to the guide member. During intentional reset, sufficient force overcomes the impeding element's resistance, allowing rotation and piston rod movement. During accidental detachment attempts, gravitational forces alone are insufficient to overcome the resistance, preventing unintended movement.
Solution Approach 2:
The impeding element changes the force parameter required for guide member rotation. By increasing the minimum force threshold needed to overcome gravitational forces and initiate reset, the system ensures that only intentional actions with sufficient force can move the piston rod, while accidental movements are blocked.
3Reliability
If an impeding element is added to prevent unintended movement, then reliability is improved, but the force required for resetting increases
Solution Approach 1:
The impeding element functions as a counterweight mechanism by applying a resisting force that balances and counteracts gravitational forces acting on the piston rod. This counterforce prevents unintended movement while allowing controlled resetting when sufficient force is applied to overcome the counterbalance.
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 effectively prevents unintended movement of the piston rod during reset, ensuring accurate reinitialization and enhancing the operational safety and reliability of the medication delivery device by requiring a higher force for resetting, thus preventing accidental detachment and ensuring proper cartridge exchange.
Implementation Method 1
the impeding element is coupled to the guide member such that in a reset state of the drive assembly the guide member may only be moved against a resistance, in particular a force exerted on the guide member by the impeding element, for example a friction force
Implementation Method 2
the force exerted on the guide member is larger than the gravitational force of the piston rod
Data Source
Figure 1
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Figure 4~5
AI summary
A drive assembly (1) for a medication delivery device (2) is provided, comprising a piston rod (3) which is movable from a start position to an end position for medication delivery and resettable from the end position to the start position. The drive assembly further comprises a guide member (4), being in engagement with the piston rod, and an impeding element (5) for impeding a movement of the guide member (4) during a reset of the piston rod (3) and thereby impeding the reset of the piston rod (3). Furthermore, a medication delivery device (2) comprising the drive assembly (1) is disclosed.