Automatic Injection Device Spring Drive Assembly Dynamics
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Solution Overview
Problem
Automatic injection devices for high viscosity medications often break due to strong springs, and their larger dimensions make them less convenient for use.
Innovation Solution
An automatic injection device with a spring drive assembly that applies a first axial force to the syringe and then a second, greater force to the piston, allowing for precise injection without predetermined piston position, and includes a selectably operable spring energy output force limiter to manage force and prevent breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a strong spring is used in the automatic injector to deliver high viscosity medication, then the injection force is sufficient, but the syringe may break during operation
Solution Approach 1:
The spring drive assembly is designed to dynamically adjust its output force based on the operational phase. During the initial phase, it applies a first axial force to advance the syringe. Upon detecting piston engagement, it automatically transitions to applying a second axial force that is substantially greater than the first force, thereby providing the high injection force needed for viscous medications while initially using a lower force to prevent syringe breakage during positioning.
Solution Approach 2:
The system changes the force parameter in two distinct stages. The spring drive assembly transitions from a first force level sufficient for syringe advancement to a second force level substantially greater than the first for actual medication injection. This parameter change is triggered by piston engagement detection, allowing the system to optimize force application throughout the injection process.
2Force
If a strong spring is used in the automatic injector, then the injection capability is improved, but the device dimensions become substantially larger
Solution Approach 1:
The spring drive assembly utilizes a dynamic force delivery mechanism that provides high force only when needed for injection, rather than requiring a continuously large spring. The assembly transitions from a lower force state during positioning to a high force state during injection, allowing for a more compact overall device design while maintaining the capability to deliver high viscosity medications.
3Adaptability or versatility
If the exact initial axial position of the piston is not predetermined, then the device is more versatile, but the force application control becomes more complex
Solution Approach 1:
The spring drive assembly automatically detects piston engagement and self-regulates the force application transition without requiring external control systems. The assembly inherently knows when to switch from the first axial force to the second axial force based on mechanical engagement with the piston, eliminating the need for complex sensors or control algorithms while maintaining versatility for different piston initial positions.
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 device effectively injects high viscosity fluids without breaking the syringe and is designed to be more compact, improving user convenience and safety.
Implementation Method 1
at least one spring drive assembly operative, when actuated, to initially apply a first axial force to the syringe, thereby to axially displace the syringe in a forward direction, and thereafter, responsive to driving engagement with the piston, to apply a second axial force, substantially greater than the first axial force
Data Source
AI summary
An automatic injection device configured for injection of a material stored in a syringe into an injection site, the syringe including a generally cylindrical storage container and a piston disposed therewithin, whose exact initial axial position within the container is not predetermined, wherein axial forward displacement of the piston in the container forces the material forwardly out of the container, the automatic injection device including at least one spring drive assembly operative, when actuated, to initially apply a first axial force to the syringe, thereby to axially displace the syringe in a forward direction, and thereafter, responsive to driving engagement with the piston, to apply a second axial force, substantially greater than the first axial force, notwithstanding the fact that the exact axial position of the piston within the container is not predetermined, to the piston, thereby to axially forwardly displace the piston relative to the syringe.