Injection Device Gauge Element Nested Dose Indicator
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Solution Overview
Problem
Existing drug delivery devices lack an effective and compact mechanism for displaying user-variable doses, particularly for visually impaired users, and often require components to protrude from the housing during dose setting and dispensing, compromising their compactness and handling.
Innovation Solution
A handheld injection device with a housing, dose indicator, and gauge element where the gauge element is axially guided and threaded with the dose indicator, providing visual feedback through markings that are visible or hidden depending on its position, and utilizing a torsion spring for dose dispensing, allowing for dose selection and dispensing without components protruding from the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dose indicator mechanism is added to display user-variable doses, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The dose indicator barrel is nested within the housing and rotates inside it, with the gauge element nested within the dose indicator barrel. This nested arrangement allows multiple functional components to occupy the same spatial envelope without increasing the overall device footprint, thereby improving measurement precision while minimizing the increase in device complexity.
Solution Approach 2:
The mechanism converts rotational movement of the dose indicator barrel into axial displacement of the gauge element through threaded engagement. This dimensional transformation allows the dose information to be displayed in both rotational (angular) and axial dimensions, providing redundant display methods that improve measurement precision without requiring additional complex mechanisms.
2Ease of operation
If components are allowed to protrude from the housing during dose setting, then ease of operation is improved, but device compactness deteriorates
Solution Approach 1:
The gauge element is nested within the dose indicator barrel, and both are contained within the housing. During dose setting, the gauge element moves axially within the confined space of the housing rather than protruding outward. This nested arrangement maintains device compactness while still providing sufficient travel distance for the gauge element to provide clear visual feedback, thereby preserving ease of operation without compromising compactness.
Solution Approach 2:
The mechanism provides dual-dimensional feedback: rotational position of the dose indicator barrel and axial position of the gauge element. This allows the user to receive operational feedback through the axial movement of the gauge element visible through the window, eliminating the need for the dose setting components to protrude from the housing, thus maintaining compactness while ensuring ease of operation.
3Measurement precision
If a gauge element with axial displacement is used for visual feedback, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The gauge element is combined with the dose indicator barrel through threaded engagement, merging the functions of dose selection and visual feedback into a single integrated mechanism. As the dose indicator barrel rotates during dose setting, the threaded engagement automatically converts this rotation into axial displacement of the gauge element, providing visual feedback without requiring a separate, complex gauge mechanism.
Solution Approach 2:
The gauge element serves multiple functions: it provides visual feedback through its axial displacement visible through the window, it limits the rotational range of the dose indicator barrel through its threaded engagement, and it provides tactile feedback through its movement. This multi-functionality improves measurement precision while avoiding the need for additional separate mechanisms, thereby controlling device complexity.
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 device offers clear, analogue optical feedback for dose setting and dispensing, improved handling due to its compact design, and reduced user effort through stored energy from the torsion spring, enhancing usability for both visually impaired and dexterous users.
Implementation Method 1
a resilient member, in this case a torsion spring, which is adapted to provide a force in the axial direction
Implementation Method 2
the gauge element is in threaded engagement with the dose indicator such that rotation of the dose indicator causes an axial displacement of the gauge element
Data Source
Figure 1~2
Figure 3~4b
Figure 5~7b
AI summary
The invention refers to a handheld injection device comprising a housing (10; 410), a dose indicator (90; 480) positioned within and axially constrained to the housing (10; 410) and rotatable with respect to the housing (10; 410) during dose setting and during dose dispensing, a gauge element (80; 490), which is at least partly interposed between the housing (10; 410) and the dose indicator (90; 480), wherein the gauge element (80; 490) is axially guided within the housing (10; 410) and in threaded engagement with the dose indicator (90; 480) such that rotation of the dose indicator (90; 480) causes an axial displacement of the gauge element (80; 490). A contrast element having a first marking is provided and at least a region of the gauge element (80; 490) is provided with a second marking, with the first marking and/or the second marking being visible through a first window (12a) or aperture in the housing (10; 410) depending on the axial position of the gauge element (80; 490) within the housing (10; 410).