Telescopic Plunger Injection Device Feedback Mechanism
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Solution Overview
Problem
Existing injection devices face challenges in providing a compact and effective activation indicator that does not increase the device's size, especially for high viscosity drugs or small needle diameters, where the delivery of a medicament may take time, and there is a need for a reliable 'Injection Complete' indication.
Innovation Solution
The use of a telescopic plunger with an indicator that expands and moves forwardly within the housing, providing an audible, tactile, or visual indication when the plunger reaches its forward position, utilizing a drive source and latch mechanism to ensure compactness and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact injection device is used, then the device size is reduced and portability is improved, but the space available for accommodation of an activation indicator is limited
Solution Approach 1:
The activation indicator is merged with the plunger assembly, specifically utilizing the trailing telescopic section as part of the indicator mechanism. This integration eliminates the need for separate indicator components, reducing overall device volume while maintaining indicator functionality.
Solution Approach 2:
The telescopic plunger sections serve multiple functions: they provide the mechanical drive for medicament delivery, enable compact storage through telescopic collapse, and simultaneously act as the activation indicator when the trailing section emerges. This multi-functionality reduces the number of separate components needed in the compact device.
2Reliability
If an activation indicator is provided for high viscosity drugs or small needle diameters, then injection completion feedback is improved, but the device size increases
Solution Approach 1:
The plunger assembly serves itself as the indicator mechanism. The trailing telescopic section of the plunger directly provides the activation indication when it emerges from the housing, eliminating the need for separate indicator mechanisms that would increase device size.
Solution Approach 2:
The emergence of the trailing telescopic section from the housing provides immediate visual and tactile feedback to the user that injection is complete. This feedback mechanism is inherently tied to the plunger's mechanical movement, ensuring reliable indication without adding extra components.
3Volume of moving object
If telescopic plunger sections are used to maintain compactness, then the device remains portable, but the mechanism complexity increases
Solution Approach 1:
The plunger is constructed with telescopic sections that nest within each other when collapsed, similar to nested dolls. This allows the plunger to occupy minimal space within the housing during storage while extending to full length during operation, maintaining device compactness without requiring complex external mechanisms.
Data Source
Figure 1a
Figure 1b
Figure 2~3b
AI summary
An injection device (1) for the delivery of medicament is disclosed having an indicator for providing an activation indication. The device comprises a housing (10); a plunger (40) slidably mounted within the housing; an actuation mechanism (30) configured, in use, to move the plunger (40) forward relative to a syringe (20) so as to express medicament from the syringe. The device also includes an indicator element (50) responsive to the forward movement of the plunger (40) and configured to provide an audible and/or tactile and/or visual indication when the plunger reaches or approaches its forward position. The plunger (40) comprises an elongate shaft formed of at least two telescopic sections (42, 48). The actuation mechanism (30) acts on the plunger (40), in use, to expand the telescopic sections and to sequentially move each of the telescopic sections forwardly within the housing. The indicator element (30) is arranged to be responsive to the forward movement of the trailing telescopic section (48).