Injection Device Dose Indicator with Helical Scale
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Solution Overview
Problem
Existing injection devices for administering liquid medicaments face challenges in providing an easy-to-use, compact design with intuitive dose setting and efficient product delivery, particularly in ensuring the correct dosage and preventing over- or under-administration.
Innovation Solution
A drive and dosing device with a sleeve-shaped housing featuring a dose display element and a pointing device, allowing for easy dose setting through a helical or gradient-free scale, combined with a dosing member and actuating mechanism that ensures accurate dose administration and prevents exceeding the maximum dose by locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact design is implemented in the injection device, then the device size is reduced, but the ease of operation for dose setting may be compromised
Solution Approach 1:
The dose indicator element is integrated within the housing structure, with the dose scale arranged around the circumference of the housing. The indicator element rotates within the housing to display different dose values, creating a nested configuration that saves space while maintaining full dose setting functionality.
Solution Approach 2:
The dose scale is arranged in a helical shape around the circumference of the dose indicator element, transitioning from a linear one-dimensional scale to a three-dimensional helical arrangement. This allows the dose scale to wrap around the indicator element multiple times, enabling a compact design that fits more dose values into a smaller spatial footprint while remaining easily readable.
2Adaptability or versatility
If a helical dose scale is used on the dose indicator element, then the dose setting range is increased, but the device complexity increases
Solution Approach 1:
The dose indicator element serves multiple functions: it displays the current dose setting, indicates the maximum dose that can be set, and provides tactile feedback through its helical structure. The same helical dose scale that increases the range also provides mechanical engagement features that simplify the overall device architecture by combining indication and control functions in a single element.
3Reliability
If locking mechanisms are added to prevent over- or under-administration, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The dose indicator element is pre-configured with a maximum dose indication that mechanically limits the rotation range. The helical dose scale is designed such that completing full rotations automatically prevents exceeding the predetermined maximum dose, embedding the safety function into the basic dosing mechanism rather than adding separate locking components.
Solution Approach 2:
The dose indicator element provides self-limiting functionality through its helical structure and integration with the drive mechanism. The mechanical engagement between the dose indicator element and the drive mechanism automatically prevents over-dosing by limiting rotation to the maximum safe dose, eliminating the need for external locking mechanisms while maintaining reliability.
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 enables intuitive and accurate dose setting and administration, preventing errors by locking mechanisms that prevent over- or under-administration, ensuring efficient use and disposal as a whole after product depletion.
Implementation Method 1
at least one ejection spring (11), arranged between the abutment (4i) and the drive member (8), which is pre-tensioned upon delivery with sufficient energy to eject the drive member (8) from its initial position
Implementation Method 2
The at least one ejection spring (11) is pre-tensioned upon delivery with sufficient energy to eject the drive member (8)
Implementation Method 3
The first and second helical compression springs (11a, 11b) are supported in series on the intermediate element (11c) and on the abutment (4i) and on the drive member (8)
Implementation Method 4
The first and second helical compression springs (11a, 11b) are supported in series
Data Source
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AI summary
A drive and metering device for an injection device for administering a liquid product, in particular a drug, from a product container is described, wherein the drive and metering device allows for the adjustment of the product dose to be administered. The drive and metering device includes, among other things, a clutch which, upon actuation of an actuator, releases a rotation of a rotary element relative to a housing, and upon release of the actuator, blocks the rotation of the rotary element relative to the housing. The drive and metering device is suitable for product containers with a reduced diameter and may, for this purpose, include a compression spring or a first compression spring with an outer diameter larger than the inner diameter of the product container.