Autoinjector Spring Mechanism for Automatic Dose Delivery
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Solution Overview
Problem
Existing injection devices require manual operation to administer a set dose of injection liquid, lacking an automatic mechanism for ensuring precise and efficient delivery.
Innovation Solution
An injection device with a spring mechanism that tensions between the injection sleeve and the housing, allowing automatic ejection of the set dose when the spring's stored force is released, enabling automatic injection without manual operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual operation is used to administer injection liquid, then device structure remains simple, but operator effort increases and dosing consistency decreases
Solution Approach 1:
The spring is pre-tensioned during the dose setting phase, storing elastic energy that will be released automatically during injection. This preliminary action eliminates the need for manual operation during the actual injection, reducing operator effort while maintaining a relatively simple device structure.
Solution Approach 2:
The device uses its own internal spring mechanism to automatically administer the injection after dose setting, without requiring external manual operation. The spring-driven system self-actuates the plunger to deliver the pre-measured dose, improving ease of operation.
2Reliability
If automatic injection mechanism is implemented, then dosing consistency improves, but device complexity increases
Solution Approach 1:
The metering element performs preliminary dosing measurement by rotating to a specific position that tensions the spring to a precise degree. This pre-measurement ensures that the subsequent automatic injection delivers a consistent, predetermined dose, improving reliability without requiring complex control systems.
Solution Approach 2:
The patent replaces manual mechanical operation with an automatic spring-driven mechanical system. The spring mechanism converts rotational motion during dose setting into linear motion during injection, providing consistent dosing through mechanical precision rather than human operation.
3Productivity
If spring mechanism is added for automatic ejection, then injection efficiency improves, but device volume increases
Solution Approach 1:
The spring is positioned within the hollow cylindrical metering element, and the plunger is nested within the injection needle assembly. This nested arrangement allows the spring mechanism to be integrated into the existing device structure without significantly increasing the overall device volume, while still providing automatic injection efficiency.
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
Ensures precise and efficient automatic delivery of the set dose of injection liquid, reducing operator effort and improving consistency in dosing, while maintaining a compact device design.
Implementation Method 1
The injection device has a spring mechanism that tensions between the injection sleeve and the housing, allowing automatic ejection of the set dose when the spring's stored force is released
Implementation Method 2
An injection sleeve moves distally via a first threaded connection. During this movement, the injection sleeve moves distally out of the housing. The threaded connection of the injection sleeve can be designed to allow the sleeve to travel a relatively large axial distance
Data Source
Figure 1~2
Figure 3~4
Figure 5~11
AI summary
The invention relates to an injection device (1, 101) having a housing (2) and a metering element (18) mounted in the housing (2) in a rotatable manner and in a fixed manner in the direction of a central longitudinal axis (50). The metering element (18) is connected via a first threaded connection (19) to an injection sleeve (17), which is rotationally fixed to the housing (2) and is held in a movable manner in the direction of the central longitudinal axis (50). When the injection liquid dose to be ejected is set, the metering element (18) rotates relative to the housing (2), and the injection sleeve (17) moves in the distal direction (30) on the basis of the first threaded connection (19). When the set injection liquid dose is ejected, the injection sleeve (17) moves in the proximal direction (31), and the metering element (18) rotates in the opposite direction on the basis of the first threaded connection (19). The aim of the invention is to allow an automatic injection of injection liquid. This is achieved in that the injection device (1, 101) has a spring (9), a first end (70) of which is supported on the injection sleeve (17) and a second end (71) of which is supported on the housing (2), and when the injection liquid is ejected, the spring moves the injection sleeve (17) in the proximal direction (31), thereby causing the set injection liquid dose to be ejected.