Injection Device Cam Mechanism for High-Viscosity Medicament Delivery
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Solution Overview
Problem
Existing injection devices for high-viscosity medications require high forces and are cumbersome, and lack effective mechanisms for indicating injection progress to users, particularly for self-administration.
Innovation Solution
An injection device with a spirally wound spring drive unit and a tactile, audio, and visual indication mechanism to provide feedback on injection progress, allowing users to feel, hear, and see the injection status through a combination of protrusions, sounds, and visual cues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a high-force spring is used to expel high-viscosity medicament through a fine needle, then the injection capability is improved, but the device size becomes unacceptably large
Solution Approach 1:
The patent employs a cam mechanism that converts rotational motion into axial motion, dynamically adjusting the plunger position during injection. The cam profile is designed to provide variable force throughout the injection cycle, maximizing force when needed while maintaining a compact spring size.
Solution Approach 2:
The invention introduces a rotational dimension to the traditionally linear injection mechanism. By rotating the cam follower around a cam surface, the system achieves complex axial motion patterns in a compact space, replacing a large linear spring with a smaller rotational mechanism.
2Loss of information
If a tactile signalling member is added to indicate injection progress, then user feedback is improved, but device complexity increases
Solution Approach 1:
The patent integrates the tactile signalling function into the existing cam mechanism. The cam follower itself serves dual purposes: driving the plunger and providing tactile feedback through its rotational movement against the cam surface. This eliminates the need for separate indication mechanisms.
Solution Approach 2:
The cam follower is designed as a multi-functional component that simultaneously performs the driving function (moving the plunger) and the signalling function (providing tactile feedback). This universal component approach reduces overall device complexity while achieving multiple objectives.
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
Enables efficient and safe injection of high-viscosity medications with clear user feedback on injection completion, reducing user effort and anxiety while maintaining a compact device size.
Implementation Method 1
a first energy accumulating member arranged in the interior of the housing of the injection device and adapted to accumulate and store energy
Data Source
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AI summary
The present invention relates to an Injection device comprising a housing (2, 3, 4, 5), a container holder (10), said container holder (10) being configured for accommodating a medicament container (12) having a needle (13) attached to one end thereof and a stopper sealingly and slidable arranged inside said medicament container (12) at the other end thereof, a drive unit comprising a plunger rod (60) and plunger drive means (50, 70), said drive unit further comprising a first energy accumulating member (40), wherein said plunger drive means (50, 70) is operationally associated with said first energy accumulating member (40), and an injection indication mechanism (182, 204, 212), wherein the injection indication mechanism (182, 204, 212) comprises a tactile signalling element (204, 212) and a drive mechanism (182) for driving said tactile signalling member, said drive mechanism (182) being coupled to said plunger drive means (50, 70).