Resilient Indicator Arms for Drug Delivery Completion Visibility
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Solution Overview
Problem
Visual indicators in drug delivery devices are often obscured and difficult for users to see unless the device is held properly, making it challenging for users to determine when the drug delivery is complete.
Innovation Solution
A drug delivery device design featuring a subassembly with a housing, plunger rod, drive member, plunger rod follower, and an indicator with resiliently-biased arms and protrusions that become visible through windows in the housing after activation, providing a clear visual indication of drug delivery completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If visual indicators are placed behind a window in the device housing, then the device structure is compact and protected, but the indicator visibility is reduced and difficult for users to see
Solution Approach 1:
The indicator arm is designed to be resiliently-biased and movable, transitioning from a retracted position during drug delivery to a protruding position when delivery is complete. This dynamic movement allows the indicator to actively change its visibility state based on device operation status, resolving the contradiction between protected positioning and visibility.
Solution Approach 2:
The indicator solution moves from a two-dimensional visual display behind a window to a three-dimensional protruding element that extends beyond the housing surface. By adding the dimension of protrusion, the indicator becomes visible from multiple angles and distances, eliminating the need for precise device alignment while maintaining structural protection.
2Difficulty of detecting and measuring
If the device requires proper holding alignment for indicator visibility, then the indicator can be seen, but user convenience is reduced and operation becomes more difficult
Solution Approach 1:
The resiliently-biased indicator arm automatically protrudes when the plunger rod reaches its retracted position, providing a passive, self-activating visibility mechanism. Users do not need to manipulate the device in specific ways; the indicator responds automatically to the completion of drug delivery, greatly enhancing ease of operation.
3Difficulty of detecting and measuring
If a resiliently-biased indicator arm with protrusion is used, then indicator visibility is greatly improved, but device complexity increases
Solution Approach 1:
The indicator arm is integrated with the existing plunger rod follower component, combining the function of tracking plunger rod position with the function of visual indication. This merging eliminates the need for separate indicator mechanisms while achieving improved visibility through the resiliently-biased protruding arm.
Solution Approach 2:
The resiliently-biased indicator arm is self-activating and self-resetting. It automatically protrudes when the plunger rod retracts and automatically returns to its retracted position when the device is reset, requiring no additional actuators, power sources, or complex control mechanisms. This self-service capability maintains device simplicity while achieving excellent visibility.
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
Ensures that users can easily and accurately determine when the drug delivery is finished, enhancing usability by making the completion indicator highly visible without requiring proper device alignment.
Implementation Method 1
an indicator received at least partially in the housing interior, including a proximal end, a distal end, and a sidewall therebetween defining an indicator interior, the indicator having one or more resiliently-biased arms having a protrusion thereon
Data Source
AI summary
Provided herein is a subassembly for a drug delivery device, including a housing defining an interior, the housing including at least one opening therethrough, a plunger rod having a proximal end and a distal end, a drive member received in the housing interior and configured to displace the plunger rod distally, a plunger rod follower having a proximal end and a distal end, the distal end of the plunger rod follower configured to couple with the proximal end of the plunger rod, and an indicator having one or more resiliently-biased arms having a protrusion thereon, wherein the protrusion is configured to be received at least partially within the opening in the housing following activation of the drug delivery device.