Helical Dose Scale Injection Device Assembly Simplification
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Solution Overview
Problem
Existing injection devices are complex and demanding in terms of final assembly, leading to increased manufacturing costs and inefficiencies, particularly due to the need for engaging threads of different pitches during assembly.
Innovation Solution
A drive and metering device with a housing that includes a helical dose scale and a dosing member, where the thread pitch of the dose display element and the bearing element is unequal to the pitch of the helical scale, allowing for easier assembly and reducing costs by eliminating the need for a thread engagement with the housing during dose setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dose indicator element is engaged with two threads of different pitches during assembly, then the device achieves proper dose setting and indication, but the assembly process becomes complex and time-consuming
Solution Approach 1:
The patent extracts the thread engagement function from the housing and relocates it to the drive element. The dose indicator element now only engages with the drive element's thread, eliminating the need for simultaneous engagement with two different threads during assembly. This simplifies the assembly process while maintaining proper dose setting functionality.
2Ease of manufacture
If the thread pitch of the dose indicator element equals the pitch of the helical scale, then the assembly is simpler, but the scale values cannot be read accurately during dose adjustment
Solution Approach 1:
The patent changes the pitch parameter of the thread engagement between the dose indicator element and the drive element to be different from the helical scale pitch. This parameter modification allows the dose indicator element to rotate relative to the housing during dose adjustment, enabling accurate scale readings while maintaining simple assembly through single thread engagement.
3Reliability
If multiple thread engagements are required during assembly, then the device achieves proper mechanical coupling, but manufacturing costs increase
Solution Approach 1:
The patent extracts one of the thread engagement requirements from the housing and transfers it to the drive element. This reduces the number of thread engagements from two to one during assembly, simplifying the manufacturing process and reducing costs while maintaining reliable mechanical coupling through the remaining thread engagement between the dose indicator element and drive element.
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 simplifies the assembly process and reduces manufacturing costs by enabling intuitive dose adjustment and dispensing, while ensuring accurate reading of scale values without the complexity of multiple thread engagements.
Implementation Method 1
A helical or spiral dose scale is arranged around the circumference of the dose indicator element
Implementation Method 2
The dose indicator element has a thread that engages with a thread in the bearing element
Data Source
Figure 1
Figure 2
Figure 3a~3d
AI summary
The inducing- and dosing device has a dose display element (10), where a helical dosage scale (10a) is arranged on the periphery of the dose display element. The dosing display element is screwed around a rotary axis relative to a pointing device (4a) by rotating a dosing unit (3) relative to the indicating device for setting the dose to be applied. A value of the dosing scale is read by the pointing device. A bearing element (9) has a threading (9a), which is engaged with the threading (10b) of the dosing display element.