Drug Delivery Drive Mechanism Eliminating Priming
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Solution Overview
Problem
Drug delivery devices often require a priming operation before the first use, which can lead to user errors and waste of medicinal product due to manufacturing tolerances, and users may accidentally inject the priming dose instead of the intended dose.
Innovation Solution
A drive mechanism with a first and second state, where the adjusting member is rotatable in the first state to adjust the piston rod's position and locked in the second state to prevent rotation, eliminating manufacturing tolerances and allowing direct dose setting and dispensing without priming for the first dose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a priming operation is required before first use to eliminate manufacturing tolerances, then the accuracy of subsequent doses is improved, but the device complexity and user error risk increase
Solution Approach 1:
The patent applies preliminary action by pre-adjusting the piston rod axial position during manufacturing to account for tolerances. The adjusting member is pre-configured in a first state that compensates for potential misalignment, eliminating the need for user-performed priming operations while ensuring accurate dose delivery from first use.
2Ease of manufacture
If the adjusting member is rotatable to adjust piston rod position, then the ease of manufacture is improved, but the reliability of dose delivery worsens due to potential accidental rotation
Solution Approach 1:
The patent applies dynamics by implementing a two-state adjusting member that transitions from a rotatable first state (during manufacturing) to a non-rotatable second state (during use). This dynamic configuration allows easy manufacturing adjustment while ensuring reliability during actual dose delivery, as the locking mechanism prevents accidental rotation in the second state.
3Measurement precision
If a priming operation is performed to eliminate manufacturing tolerances, then the measurement precision of the first dose is improved, but the loss of medicinal product increases
Solution Approach 1:
The patent applies preliminary action by pre-compensating for manufacturing tolerances during the manufacturing process itself, rather than requiring a priming operation that wastes medicinal product. The adjusting member is pre-configured to ensure accurate piston rod positioning, allowing the first dose to be both accurate and usable without discarding priming material.
Data Source
AI summary
The present disclosure concerns a drive mechanism for a drug delivery device, having a first and a second state and comprising a piston rod configured to be moved in a distal direction when the drive mechanism is operated and an adjusting member, wherein the adjusting member is rotatable relative to a body of the drug delivery device in the first state of the drive mechanism and is prevented from rotating relative to the body in the second state of the drive mechanism, and wherein the adjusting member is configured to adjust an axial position of the piston rod in the first state of the drive mechanism.