Adjustable End Stop Injection Device Dosage Control
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Solution Overview
Problem
Existing automatic injection devices require multiple units for different dosages of injection liquid, leading to complexity and the need for separate devices, especially for medications with short storage life and varying user needs.
Innovation Solution
An injection device with a setting device that allows the operator to adjust the quantity of injection liquid by rotating a setting ring, which adjusts the position of the end stop, enabling a simple and precise setting of the dosage without requiring manual tensioning of the injection spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single injection device is used for multiple dosages, then device versatility is improved, but device complexity increases
Solution Approach 1:
The end stop is made adjustable along the longitudinal central axis of the injection device, allowing dynamic repositioning to define different terminal positions for the metering piston. This enables a single device to accommodate multiple dosages by changing the end stop position rather than requiring multiple fixed devices
Solution Approach 2:
The injection device is designed to perform multiple dosage functions through a single device by incorporating an adjustable end stop that can be positioned at different locations along the longitudinal axis, allowing the same device to deliver various injection volumes
2Ease of operation
If the injection spring is pre-tensioned in the housing, then ease of operation is improved, but device complexity increases
Solution Approach 1:
The injection spring is pre-tensioned during the manufacturing process and fixed in the housing before delivery to the user. This preliminary action eliminates the need for operators to manually tension the spring, simplifying operation while the spring remains integrated into the housing structure
3Measurement precision
If the end stop position is adjustable, then dosage precision is improved, but device complexity increases
Solution Approach 1:
The adjustment mechanism is segmented into discrete positional settings along the longitudinal central axis, allowing the end stop to be positioned at specific intervals corresponding to different dosages. This segmentation provides precise dosage control while keeping the adjustment mechanism simple and manageable
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
Enables a single device to handle various dosages efficiently, reducing complexity and the need for multiple devices, while maintaining high stability and allowing for precise control of the injection quantity, even with highly viscous liquids.
Implementation Method 1
an injection spring (9), which by way of its distal end is supported on a distal wall (36) of the upper housing part (3), and by way of its proximal end is supported on the periphery (22) of the metering piston (11)
Implementation Method 2
A simple construction is achieved when the setting ring is connected to the housing by way of a threaded connection, and a rotation of the setting ring causes a movement of the setting ring in the direction along the longitudinal central axis of the injection device
Data Source
AI summary
An injection device is for automatically squeezing injection liquid from a container and includes: a housing; an injection spring configured to cause squeezing of the injection liquid from the container; the injection device defining a longitudinal central axis and a proximal direction; a metering piston mounted so as to be movable in the direction of the longitudinal central axis of the injection device; the metering piston being configured to, when squeezing injection liquid, move in the proximal direction; a setting device for setting the quantity of injection liquid to be squeezed; an end stop which establishes a terminal position of the metering piston; and, the setting device having an adjustment unit configured to adjust the position of the end stop.