Autoinjector Push Rod Assembly for Multi-Dose Delivery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing automatic medication injection devices are limited in their ability to deliver multiple doses without requiring manual re-arming and often have complex mechanisms that increase manufacturing costs and reduce user-friendliness.
Innovation Solution
A reusable, spring-driven autoinjector with a push rod assembly that allows for controllable advancement with a minimum number of cooperating parts, enabling multiple doses to be delivered automatically without manual re-arming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional autoinjector design is used, then single dose or two-dose delivery is achieved, but manual re-arming is required and device complexity increases
Solution Approach 1:
The push rod assembly is designed to automatically reset and re-arm the spring mechanism after each injection cycle. The ratchet mechanism allows the push rod to move distally during injection but automatically returns it to the starting position, enabling multiple doses without manual intervention. This self-service capability resolves the contradiction by providing multi-dose functionality while keeping the mechanism relatively simple.
Solution Approach 2:
The spring is pre-loaded and stored in a compressed state within the device housing, ready to drive the injection mechanism. The push rod assembly is pre-positioned with engagement features that automatically engage with the spring mechanism. This preliminary preparation allows the device to deliver multiple doses automatically without requiring manual re-arming between injections.
2Productivity
If manual re-arming is required for each dose, then device complexity is reduced, but productivity and user convenience decrease
Solution Approach 1:
The automatic reset mechanism allows the push rod to return to its initial position after each injection, automatically re-compressing the spring and preparing the device for the next dose. This eliminates the need for manual re-arming operations, significantly improving productivity by allowing continuous automatic injection cycles without increasing overall device complexity.
Solution Approach 2:
The device maintains continuous readiness for injection through the automatic reset mechanism. After each dose is delivered, the push rod automatically returns to its starting position and the spring is re-compressed, ensuring the device is immediately ready for the next injection without interruption or manual intervention. This continuous operation capability increases productivity while keeping the mechanism simple.
3Ease of manufacture
If a simple push rod assembly is used, then ease of manufacture is improved, but controllability of dose delivery may be compromised
Solution Approach 1:
The push rod assembly is segmented into distinct functional components: the push rod itself, the ratchet mechanism, the spring engagement features, and the position setting features. Each segment performs a specific function and can be manufactured independently using simple processes. This segmentation maintains ease of manufacture while ensuring reliable dose delivery control through the coordinated action of each segment.
Solution Approach 2:
The ratchet mechanism acts as an intermediary between the spring force and the push rod movement. It allows the push rod to move distally during injection while preventing proximal movement, ensuring controlled dose delivery. This intermediary mechanism is simple in design but effective in controlling the injection process reliably without complicating the overall manufacturing process.
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 provides a user-friendly and cost-effective means of delivering multiple medication doses automatically, simplifying the manufacturing process and enhancing the device's usability and efficiency.
Implementation Method 1
The drive mechanism includes one or more driving springs in association with a push rod assembly
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A medical injection device, including : a medication container having a movable piston; a push rod assembly displaceably disposed in the medical injection device, the push rod assembly having a plurality of spaced-apart position setting means disposed along the length thereof, the push rod assembly selectively displacing the movable piston to dispense medicament from the medication container; a spring to bias the push rod assembly to move toward the distal end of the medical injection device; a releasable restraining means configured to releasably restrain the push rod assembly in a locked state against the biasing of the spring, wherein, upon release of the releasable restraining means, the push rod assembly moves under force of the spring toward the distal end of the medical injection device; and an arming means configured to move the push rod assembly toward the proximal end of the medical injection device.