Injection Dosing Mechanism With Direct Housing Coupling
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Solution Overview
Problem
Existing injection devices for administering liquid substances, such as insulin and hormone preparations, are complex and require multiple components, making them expensive to manufacture and assemble, and are not optimized for single-use applications where a resettable plunger rod is not necessary.
Innovation Solution
A dosing and dispensing mechanism for a single-use injection device that uses a drive sleeve and actuating element with a direct rotational coupling to the housing, eliminating the need for additional components and allowing for a simple, effective, and efficient dispensing process through a non-rotatable piston rod movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex mechanism with multiple components (click mechanism, coupling, drive sleeve, dosing element) is used to prevent accidental adjustment of the piston rod, then reliability is improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent combines the dosing element and drive sleeve into a single integrated component. The drive sleeve directly receives rotational input from the dosing element without requiring separate coupling mechanisms, click mechanisms, or intermediate transmission elements. This merging eliminates multiple parts while maintaining the anti-reverse function through the direct mechanical connection and thread geometry.
Solution Approach 2:
The patent removes unnecessary intermediate components from the mechanism. Specifically, it eliminates the click mechanism, separate coupling elements, and complex drive transmission systems found in prior art. The direct connection between dosing element and drive sleeve extracts only the essential functional elements needed for dosing and anti-reverse protection.
2Adaptability or versatility
If a reusable injection pen design with retractable plunger rod is used, then adaptability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent designs a disposable injection device where the entire mechanism including drive sleeve, piston rod, and cartridge is intended for single use. This eliminates the need for complex retractable plunger rod mechanisms required in reusable pens, as the device is discarded after one administration. The simplified non-retractable design significantly reduces manufacturing complexity and cost.
Solution Approach 2:
Instead of designing a reusable device with complex reset mechanisms, the patent inverts the approach by designing a disposable device where simplicity is achieved through single-use architecture. The plunger rod does not need to retract or reset, eliminating an entire class of mechanical components required for reusability.
3Reliability
If additional coupling elements and click mechanisms are added to connect the drive sleeve and dosing element, then reliability of dose setting is improved, but ease of manufacture deteriorates
Solution Approach 1:
The dosing element and drive sleeve are merged into one integrated component with direct mechanical coupling. The drive sleeve forms part of the dosing element structure, eliminating the need for separate coupling elements, teeth, or click mechanisms. This single-piece design maintains dose setting reliability through direct mechanical engagement while dramatically simplifying manufacturing and assembly.
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 mechanism enables a compact, cost-effective, and easy-to-assemble injection device with fewer parts, ensuring secure and accurate dosing and dispensing without additional energy sources, suitable for single-use applications.
Implementation Method 1
The piston rod has a first thread with which the piston rod is screwed into the housing, and a second thread which has a different pitch direction than the first thread. The drive sleeve is in threaded engagement with the second thread.
Implementation Method 2
no additional force is required when dispensing to overcome the frictional resistance of a securing element, such as a ratchet
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to an injection device (1) for discharging a product dose by the manual advancement of a plunger rod (70) into a cartridge (13) held in the injection device (1), the injection device comprising a dosing- and discharge mechanism having: a housing (10) with a longitudinal axis; a drive sleeve (50) for driving the plunger rod (70), the sleeve being longitudinally displaceably provided in the housing (10); and an actuating element (60) for setting the dose, said actuating element (60) being non-rotatably connected to the drive sleeve (50) and displaceable along the longitudinal axis relative to said drive sleeve (50), wherein the actuating element (60) can be rotated relative to the housing (10) in order to set the dose. The actuating element (60) comprises a first coupling element and the housing (10) comprises a second coupling element, said first and second coupling elements being couplable in order to discharge the dose, so that, when coupled, the actuating element (60) is non-rotatably connected to the housing (10) and displaceable along the longitudinal axis relative to said housing (10).