Injection Pen Dose Limiter for Prescribed Dose Lockout
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection devices lack the ability to prevent the setting or expelling of doses that do not match predefined or prescribed dose sizes, which is crucial for ensuring therapeutic efficacy and user safety, particularly for patients with impaired vision or dexterity.
Innovation Solution
An injection device with a windup expelling mechanism and dose setting mechanism that includes a dose tracking member and limiter, which blocks actuation of the trigger when the set dose does not match predefined values, using keying features and mechanical engagement to prevent improper dose dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dose setting mechanism is provided to allow user-selectable doses, then the adaptability of the injection device is improved, but the risk of administering incorrect doses increases
Solution Approach 1:
The limiter is positioned to preemptively block the trigger's movement before an incorrect dose can be administered. The keying features on the limiter and dose tracking member create a mechanical interlock that prevents trigger actuation unless the dose tracking member is at a valid position, thus preventing harmful action before it can occur.
Solution Approach 2:
The limiter acts as an intermediary component between the trigger and the dose tracking member. It translates the rotational position of the dose tracking member into a mechanical blocking or permitting action on the trigger, mediating the interaction between user input and dose delivery to ensure only valid doses can be administered.
2Reliability
If a limiter with keying features is added to block improper dose actuation, then the reliability of dose administration is improved, but the device complexity increases
Solution Approach 1:
The limiter combines multiple functions into a single component: it serves as both a blocking mechanism for the trigger and a receiver of positional information from the dose tracking member via keying features. The keying features themselves are simple geometric shapes that encode valid dose positions, merging the verification logic into the mechanical structure rather than requiring separate electronic or complex mechanical systems.
3Object-affected harmful factors
If the limiter blocks the trigger at certain positions, then the safety against incorrect dosing is improved, but the ease of operation is worsened
Solution Approach 1:
The dose tracking member serves itself by automatically positioning the keying features relative to the limiter based on the selected dose. When the user rotates the dose tracking member to select a dose, the keying features move accordingly, and the limiter automatically engages or disengages based on whether the selected dose is valid, without requiring additional user actions or judgments.
Data Source
AI summary
The disclosure relates to an injection device for expelling of a number of preset or user-selectable doses of a medicament. The injection device includes an elongated housing extending along an axial direction and configured to accommodate a cartridge containing the medicament and having a bung sealing a proximal end of the cartridge, a windup expelling mechanism, and a dose setting mechanism. The dose setting mechanism includes a handle, a dose tracking member, and a limiter. The dose tracking member is rotatable relative to the housing within a range of positional states and operatively connectable to the handle for tracking a rotation thereof. The limiter is operationally engageable with the dose tracking member and a trigger of the windup expelling mechanism for blocking actuation of the trigger when the dose tracking member is in one of a number of predetermined sections of the range of positional states.