Rotating Display Mechanism for Injection Pen Dose Readability
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Solution Overview
Problem
Existing injection devices, particularly pen-type injectors, face challenges in displaying dose sizes accurately and intuitively, especially for visually impaired users, as current display arrangements can only show discrete numbers and are difficult to read due to their compact design.
Innovation Solution
A display arrangement featuring two rotatable display members with radially offset cams and a coupling mechanism, allowing for the visualization of all discrete dose sizes between 0 and 120 IU, enhancing legibility and precision by using separate members for integer and decade digits, and a retaining arrangement to prevent unintentional rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact display design is used to fit within the injection device housing, then the device size is reduced, but the display becomes difficult to read especially for visually impaired users
Solution Approach 1:
The display is segmented into two separate rotatable display members: a first display member showing integer digits (0-9) and a second display member showing decade digits (0-12). This segmentation allows each digit to be displayed separately with sufficient size for readability while keeping the overall device compact. The cam mechanism is also segmented with multiple cam lobes corresponding to different dose values.
Solution Approach 2:
The display mechanism transitions from a linear or planar display to a three-dimensional rotatable display where dose values are shown through angular positions of display members. The cam mechanism converts linear dose setting movement into rotational display member movement, utilizing the third dimension (rotation) to display dose information in a space-efficient manner that remains readable.
2Device complexity
If discrete numbers are displayed to indicate dose size, then the display structure is simplified, but the precision and continuity of dose visualization is reduced
Solution Approach 1:
The cam mechanism is pre-configured with specific cam lobes positioned at predetermined angular locations around the rotation axis. Each cam lobe corresponds to a specific discrete dose value. When the dose setting member is rotated to a desired dose, the cam mechanism automatically positions the appropriate cam lobe to engage with the display member, thereby preliminarily preparing the correct dose indication before the user reads it.
3Device complexity
If a single display member is used to show all dose values, then the device complexity is reduced, but the ability to clearly distinguish all discrete dose sizes is compromised
Solution Approach 1:
The display information is segmented across two display members: the first display member shows the units digit (0-9) and the second display member shows the tens digit (0-12). This segmentation allows all discrete dose values from 0 to 120 IU to be clearly distinguished by combining the information from both members, similar to how odometers display multi-digit numbers.
Solution Approach 2:
The cam mechanism acts as an intermediary between the dose setting member and the two display members. It receives the rotational input from the dose setting member and translates it into coordinated rotations of both display members, ensuring that the correct combination of digits is displayed simultaneously for the selected dose value.
4Ease of operation
If the display members are made rotatable to show different dose values, then the ease of operation is improved, but unintentional rotation and incorrect dosing may occur
Solution Approach 1:
The cam mechanism provides mechanical feedback through audible clicks or tactile sensations at each discrete dose position. When the dose setting member is rotated, the cam lobes engage with the display member at specific angular positions, creating detectable feedback signals that confirm the selected dose value. This feedback mechanism prevents unintentional rotation by requiring deliberate user action to move between discrete dose settings.
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 visually impaired individuals to read dose sizes unambiguously and intuitively, improving the overall usability and accuracy of dose setting and dispensing in injection devices.
Implementation Method 1
The first display member has at least one cam radially offset from a rotation axis. The coupling member is selectively engageable with the at least one cam of the first display member
Implementation Method 2
The retaining arrangement is configured to keep the coupling member and the first display member mutually engaged. The retaining arrangement prevents an unintentional rotation of the coupling member and of the second display member
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The present invention relates to a A display arrangement for an injection device for displaying the size of a dose of a medicament, the display arrangement comprising: - a housing (60) providing a rotation axis (3) extending in an axial direction (4), - a first display member (22) rotatably supported inside the housing (60) with regard to the rotation axis (3) and having at least one cam (32) radially offset from the rotation axis (3), - a second display member (24) rotatably supported inside the housing (60) with regard to the rotation axis (3) and arranged axially adjacent to the first display member (24), - a coupling member (26) rotatably engaged with the second display member (24), wherein the coupling member (26) is engaged with the at least one cam (32) of the first display member (22) when the first display member (22) is in a predefined angular position or angular range, - wherein the coupling member (26) and the first display member (22) are mutually engaged via a retaining arrangement (48) when the cam (32) and the coupling member (26) are disengaged.