Metering Device Coupling Mechanism for Injection Dose Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing injection devices lack an efficient and user-friendly mechanism for setting and dispensing doses, particularly in ensuring accurate dose delivery and preventing accidental dispensing during dose correction.
Innovation Solution
A dosing device with an actuating element that can be moved unscrewed for setting a dose, featuring a piston rod with a stop to push a plunger and a coupling mechanism that allows for rotational movement during dispensing while preventing rotation during dose correction, along with a reverse rotation lock to ensure unidirectional rotation and prevent accidental dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the actuating element is made rotatable during dose correction, then ease of operation is improved, but reliability deteriorates due to risk of accidental dispensing
Solution Approach 1:
The coupling element dynamically changes its coupling state with the actuating element based on the operational phase. During dose setting, the coupling element is decoupled allowing free rotation. During dose dispensing, the coupling element engages to couple the actuating element to the piston rod sleeve, preventing back-rotation and ensuring reliable unidirectional operation.
Solution Approach 2:
The coupling element acts as an intermediary between the actuating element and the piston rod sleeve. It selectively engages or disengages to control the transmission of rotational movement, thereby enabling the system to switch between flexible dose setting and locked dose dispensing modes without direct mechanical constraints on the actuating element.
2Reliability
If the coupling mechanism prevents rotation during dispensing, then reliability is improved, but ease of operation worsens due to restricted movement
Solution Approach 1:
The coupling element dynamically transitions between engaged and disengaged states. During dose dispensing, it engages to prevent back-rotation and ensure reliable unidirectional operation. During dose correction, it disengages to allow the actuating element to rotate freely for adjusting the dose setting.
3Manufacturing precision
If the piston rod is rotationally fixed to the piston rod sleeve, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The coupling sleeve serves as an intermediary that establishes the rotationally fixed connection between the piston rod and the piston rod sleeve. This mediator component simplifies the overall structure by providing a dedicated interface for rotational constraint, avoiding the need for complex integrated designs while ensuring precise rotational fixation during dose dispensing.
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 enables precise dose setting and delivery, providing a tactile, visual, or acoustic signal for user confirmation and ensuring that the device can only dispense when intended, thus preventing accidental product release during adjustments.
Implementation Method 1
The actuating element can be moved out of the dosing device, in particular unscrewed, to set the dose to be dispensed from the injection device. The actuating element can be guided in a housing of the injection device or in a housing of the dosing device, in particular in a threaded engagement.
Implementation Method 2
The piston rod may have a stop, in particular a flange, at its distal end, which can abut a piston contained in a cartridge. The flange can push the piston axially into the cartridge to dispense a product contained in the cartridge, in particular a liquid or a drug, from the injection device.
Implementation Method 3
A coupling element that couples the actuating element and the piston rod sleeve during a discharge movement of the actuating element in such a way that the discharge movement of the actuating element can be transmitted to the piston rod via the piston rod sleeve connected to the piston rod.
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to a dosing device for an injection device.The metering device comprises an actuating element (1) for setting or dispensing a dose from the injection device, a piston rod (2) for generating a feed motion for dispensing a dose, a piston rod sleeve (3) in which the piston rod (2) is received in such a way that the piston rod (2) can be connected to the piston rod sleeve (3) in a rotationally fixed manner, a coupling element (4) with which the actuating element (1) and the piston rod sleeve (3) can be coupled for dispensing the dose set by the actuating element (1) in such a way that a dispensing motion of the actuating element (1) is transmitted to the piston rod (2) via the piston rod sleeve (3) connected to the piston rod (2), wherein the metering device further comprises a back-rotation locking element (5) for the piston rod sleeve (3) to allow rotation of the piston rod sleeve (3) in one direction and to lock it in the opposite direction.