Cap-Actuated Dose Setting in Mechanical Injection Devices
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Solution Overview
Problem
Existing injection devices for self-administering insulin require multiple operations from users, including dose setting and injection, which can be complex and prone to errors, and do not provide clear indications of readiness for use or insufficient drug volume.
Innovation Solution
A mechanical injection device with a removable cap that automatically sets a predetermined dose upon mounting and dismounting, disabling the injection mechanism when the cap is mounted to prevent accidental dosing and indicating readiness for use by moving an injection button between positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the user manually sets the dose using a dose setting mechanism, then the dose can be adjusted to the desired amount, but the number of operations increases and the complexity of operation increases
Solution Approach 1:
The injection device automatically sets the dose by detecting the volume of liquid drug in the reservoir and adjusting the piston position accordingly, eliminating the need for manual dose setting by the user. The device serves itself by autonomously determining and configuring the appropriate dose based on the available drug volume.
Solution Approach 2:
The device incorporates a detection mechanism that monitors the liquid drug volume in the reservoir and provides feedback to the dose setting mechanism. This feedback loop enables automatic adjustment of the piston position to match the detected volume, ensuring the correct dose is set without manual intervention.
2Measurement precision
If the device requires separate dose setting and injection operations, then precise control over dosing is achieved, but the treatment regimen becomes complex and time-consuming
Solution Approach 1:
The device combines the dose setting function and injection function into a single integrated operation. When the user actuates the injection button, the device simultaneously sets the dose based on detected liquid volume and prepares for injection, eliminating the need for separate dose setting and injection steps that consume time.
Solution Approach 2:
The device performs preliminary dose setting automatically based on the detected liquid drug volume before the user initiates injection. The piston position is pre-adjusted to correspond to the available drug volume, so when injection is required, the device is already prepared with the correct dose configuration.
3Reliability
If the device provides clear indications of readiness and drug volume status, then user awareness and safety are improved, but the device complexity increases
Solution Approach 1:
The device employs color-coded visual indicators that change or display different colors to communicate device status to the user. For example, different colors indicate whether the device is ready for injection, the amount of liquid drug remaining, or operational warnings, providing clear status information through simple color cues rather than complex displays.
4Ease of operation
If the cap mounting automatically sets the dose, then the number of user operations is reduced, but the mechanism complexity increases
Solution Approach 1:
The cap serving as a protective cover is given an additional universal function: it acts as an actuator for automatic dose setting. When the cap is mounted or removed, it triggers the dose setting mechanism through a mechanical connection, allowing the same component to perform both protective and operational functions without adding separate mechanisms.
Data Source
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AI summary
A mechanical injection device (1) for injecting apportioned doses of liquid drug. The injection device (1) comprises a dose setting means, an injection means, a removable cap (15) and a cap receiving part (9) adapted to abut or engage with the cap (15) when the cap (15) is mounted on the injection device (1). The dose setting means is operatively coupled to the cap receiving part (9) in such a manner that mounting and/or dismounting of the cap (15) on/from the injection device (1) causes the dose setting means to set a dose. Thereby a correct dose of drug is automatically set during a cap on/cap off cycle. Since such a cycle is normally performed between two subsequent injections, the number of steps required to be performed by the user is reduced.