Intraocular Injection Device Spring Force Limiting Plunger
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Solution Overview
Problem
Current injection devices for intraocular delivery of viscoelastic substances face challenges in accurately dispensing metered doses due to high force requirements and potential tissue damage from excessive pressure and velocity, especially when delivering materials to small structures within the eye.
Innovation Solution
A device with a housing, plunger, and spring element that limits the force applied to the plunger, using a trigger mechanism to control the advancement of the plunger and prevent excessive pressure, allowing for precise metered dosing and reduced velocity of the injected material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plunger is used to inject viscoelastic substances into the eye, then the material can be delivered to the target structure, but excessive force and pressure may cause tissue damage
Solution Approach 1:
The patent changes the force parameter by introducing a spring element that limits the maximum force applied to the plunger. The spring constant is selected to ensure the force remains below a threshold that would cause tissue damage, while still being sufficient to deliver the viscoelastic material through the injection site.
Solution Approach 2:
The spring element acts as an intermediary between the trigger mechanism and the plunger. It mediates the force transmission by providing a controlled, limited force through its elastic properties, preventing direct transmission of excessive force from the trigger to the plunger and ultimately to the tissue.
2Productivity
If high pressure is used to deliver viscoelastic material through small structures, then the material can be pushed through the narrow passage, but tissue damage occurs
Solution Approach 1:
The patent changes the pressure parameter by using a spring element with a specific force constant that limits the maximum pressure applied to the material. This ensures the pressure is sufficient to push the viscoelastic material through small structures like Schlemm's canal, but remains below the threshold that would cause tissue damage.
Solution Approach 2:
The spring element provides dynamic force adjustment based on resistance. As the plunger encounters resistance from the small structures, the spring compresses and adjusts the force accordingly, maintaining optimal pressure throughout the injection process without exceeding tissue tolerance limits.
3Loss of time
If the plunger is advanced quickly to deliver the material efficiently, then the procedure time is reduced, but the velocity of injected material increases causing tissue damage
Solution Approach 1:
The patent changes the velocity parameter by using the spring element to control the rate of plunger advancement. The spring's elastic properties naturally limit the acceleration and velocity of the plunger, ensuring the material is injected at a controlled speed that prevents tissue damage while still achieving efficient delivery.
Solution Approach 2:
The spring element provides beforehand cushioning by being pre-loaded or designed to engage before excessive velocity can occur. It acts as a cushion that absorbs excess kinetic energy and controls the injection velocity from the start, preventing harmful high-speed injection before it can cause tissue damage.
4Ease of operation
If a simple trigger mechanism is used to advance the plunger, then the device is easy to operate, but it cannot control the force and pressure applied
Solution Approach 1:
The patent merges a simple trigger mechanism with a spring element to create a combined system that maintains ease of operation while adding force control. The user simply pulls the trigger as before, but the spring element automatically provides the controlled force, combining the simplicity of a basic trigger with the precision of spring-loaded force limitation.
Solution Approach 2:
The spring element provides self-service force control without requiring complex mechanisms or user adjustment. Once the trigger is pulled, the spring automatically regulates the force and pressure applied to the plunger, making the control function self-regulating and eliminating the need for complex manual control systems.
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 precise and controlled delivery of viscoelastic substances or other materials with reduced pressure and velocity, minimizing tissue damage and ensuring accurate metered doses, suitable for ophthalmic procedures and other therapeutic applications.
Implementation Method 1
a spring element configured to apply a spring force to the plunger and which limits a maximum force of the spring force
Data Source
AI summary
This disclosure relates generally to an injection device having a plunger configured to advance a distance into a container of material, such as a viscoelastic container; a trigger mechanism configured upon an actuation of the trigger mechanism to apply a first force to a spring element; and the spring element coupled to the plunger and configured to apply a second force to the plunger and which is configured to prevent exceeding a threshold maximum force applied to the container.