Auto-injector Thrust Collar Mechanism for Complete Medicament Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current auto-injectors face challenges in ensuring complete medicament delivery without compromising needle safety, often resulting in incomplete doses or accidental needle stick injuries due to complex mechanisms and multiple parts, which can lead to increased costs and inefficiencies.
Innovation Solution
The auto-injector design features a compact mechanism with a thrust collar and needle shroud that allows complete emptying of the syringe barrel before decoupling, utilizing a ramped engagement and rotational guidance to prevent premature release, ensuring complete medicament delivery and automatic needle safety through a single drive means and biasing mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex mechanisms with multiple parts are used to ensure needle safety and complete medicament delivery, then reliability of medicament delivery is improved, but device complexity increases and production costs increase
Solution Approach 1:
The patent combines multiple functions into a single integrated drive means that performs both complete medicament delivery and needle safety functions. The drive means is configured to advance the plunger to deliver the full dose while simultaneously controlling the needle shield to cover the needle after injection, eliminating the need for separate mechanisms for each function.
Solution Approach 2:
The drive means is designed as a multi-functional component that accomplishes multiple tasks: advancing the needle, delivering the complete medicament dose, and activating the needle safety shield. This universal component replaces what would traditionally require multiple separate mechanisms, reducing device complexity while maintaining reliability.
2Reliability
If complex mechanisms with multiple parts are used to ensure needle safety and complete medicament delivery, then reliability of medicament delivery is improved, but production costs increase
Solution Approach 1:
By merging multiple functions into a single drive means, the patent reduces the total number of parts that need to be manufactured, assembled, and quality-tested. This integration directly lowers production costs while ensuring reliable complete medicament delivery through the unified design.
Solution Approach 2:
The patent describes an auto-injector designed as a single-use disposable device. By optimizing the entire device as a disposable unit with integrated functions, manufacturing costs are reduced compared to creating complex reusable devices with multiple separate components that require maintenance and sterilization.
3Ease of operation
If premature release of the drive means is allowed, then ease of operation is improved, but complete medicament delivery cannot be ensured
Solution Approach 1:
The drive means is designed with a predetermined release mechanism that automatically disengages only after completing the full medicament delivery sequence. The ramped engagement features ensure the plunger is advanced completely through the entire dose before release, eliminating the need for user judgment about when to release and ensuring complete delivery while maintaining simplicity.
Solution Approach 2:
The auto-injector's drive means automatically controls its own release timing based on the completion of medicament delivery. The mechanism self-regulates to ensure the full dose is administered before disengaging, removing the burden of timing judgment from the user while maintaining complete delivery reliability.
4Object-affected harmful factors
If traditional auto-injector mechanisms are used, then needle safety may be compromised, but device complexity and cost increase
Solution Approach 1:
The needle safety function is merged into the same drive means that delivers the medicament. The drive means automatically advances the needle shield to cover the needle after injection, combining safety functionality with the primary injection function rather than requiring a separate safety mechanism.
Solution Approach 2:
The needle shield is designed to be automatically advanced by the drive means to cover the needle after injection completes. This self-activating safety feature eliminates the need for user action to engage safety, ensuring consistent protection while keeping the mechanism simple through automatic operation.
Data Source
AI summary
An auto-injector for administering a dose of a liquid medicament (M) comprises of a substantially cylindrical housing arranged to contain a pre-filled syringe with an injection needle, a plunger and a stopper for sealing a syringe barrel and a drive means releasably coupled to the plunger for advancing the syringe in the proximal direction (P) for needle insertion into an injection site and for displacing the dose of medicament (M) into the injection site. The drive means is arranged to be decoupled from the plunger for advancing a needle shroud to a safe position (PS) to surround the injection needle after the injection. According to the invention, the drive means bears against a thrust collar arranged to be releasably coupled to the plunger through a ramped engagement of a first tongue and a first recess so as to rotate the thrust collar on translation in proximal direction (P). At least one longitudinal gap (G1, G2) is provided for guiding at a first and/or second protrusion of the thrust collar to prevent a rotation of the thrust collar. A circumferential gap (G3) is arranged to allow the thrust collar to rotate out of engagement to the plunger on removal of the auto-injector from the injection site.An auto-injector includes a housing, a thrust member comprising a radial projection configured to engage a ramped surface within the housing when the thrust member is in a first rotational position and to disengage from the ramped surface when the thrust member is moved to a second rotational position, a drive spring disposed within the housing, and a needle shroud configured to (i) inhibit rotation of the thrust member when the needle shroud is in an extended positon and the thrust member is in the first rotational position, (ii) allow the thrust member to rotate from the first rotational position to the second rotational position when the needle shroud is in a retracted positon, and (iii) permit the thrust member, after the thrust member has been rotated to the second rotational position, to be moved axially by the drive spring.