Torque-Driven Drug Injector With Damping and Filtration
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Solution Overview
Problem
Existing autoinjectors using coil springs for actuation experience issues such as abrupt contact with medicament storage, leading to user discomfort and potential damage due to high forces, and the dispersion of unwanted particles in medicaments.
Innovation Solution
A torque-driven injector system with a damper mechanism and a filtering device, utilizing a tightly wound torque spring and a damper mechanism to control the force and velocity of medicament delivery, along with a filter member to restrict particle entry, reducing impact and ensuring smooth administration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a coil spring structure is used to provide actuation energy, then simplicity of use and device automation are improved, but excessive energy is input to the system at the end of plunger stroke causing abrupt contact and user discomfort
Solution Approach 1:
The system transitions from a static spring mechanism to a dynamic torque-driven mechanism with controlled rotational movement. The torque spring provides consistent torque throughout the actuation cycle, and the threaded plunger rod converts this rotational torque into controlled linear motion, enabling smooth, progressive drug delivery without abrupt impacts.
Solution Approach 2:
The system changes the actuation parameter from linear spring force to rotational torque. The torque spring maintains constant torque output throughout the rotation, and the threaded mechanism converts this to controlled linear force application. This parameter change enables smooth, progressive actuation rather than the abrupt motion caused by conventional spring mechanisms.
2Force
If higher spring constants are used to deliver higher viscosity drugs, then sufficient force is provided, but the plunger face makes abrupt contact with the storage portion causing mechanical bumps and potential damage
Solution Approach 1:
The system uses dynamic rotational control to manage the force application. The torque spring provides consistent torque throughout the rotation, and the threaded plunger rod converts this to progressively increasing linear force. This dynamic control prevents abrupt contact by maintaining smooth, controlled progression throughout the actuation cycle.
Solution Approach 2:
The torque-driven threaded mechanism provides continuous, smooth force application throughout the entire actuation cycle. Unlike conventional springs that deliver force in abrupt increments, the rotational-to-linear conversion mechanism ensures continuous progression, eliminating mechanical bumps and ensuring gentle contact between the plunger face and storage portion.
3Force
If high force springs are used to deliver viscous drugs, then sufficient driving force is provided, but undesirably high shear rates are produced on the drug product
Solution Approach 1:
The system changes the force delivery parameter from high-force, low-duration spring action to controlled torque application. The threaded mechanism distributes the force application over the entire rotational cycle, maintaining lower instantaneous shear rates while still providing sufficient driving force for viscous drug delivery.
4Productivity
If pre-filled syringes are initially filled, then medicament is ready for delivery, but unwanted particles may be dispersed within the medicament complicating delivery and contaminating the product
Solution Approach 1:
A filter member is introduced as an intermediary component between the syringe barrel and the needle assembly. This filter captures and removes unwanted particles from the medicament stream before they can enter the needle and contaminate the delivered product, while allowing the medicament itself to pass through for delivery.
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 system provides a comfortable and safe medicament delivery experience by minimizing sudden movements and preventing particle contamination, while maintaining consistent torque throughout the actuation process.
Implementation Method 1
The actuating mechanism includes a torque spring that exerts a torque that urges the medicament through the filter member
Implementation Method 2
a threaded plunger rod that threadably couples to a threaded opening in the frame member
Implementation Method 3
a damper mechanism that exerts an opposing force or torque to dampen the torque exerted by the torque spring
Implementation Method 4
an optional filter member disposed adjacent to the needle assembly... The filter member restricts particles dispersed within the medicament from entering the needle assembly
Data Source
AI summary
An injector includes a housing having a syringe assembly and an actuating mechanism at least partially disposed within the housing. The syringe assembly includes a syringe barrel that stores a medicament to be injected into a user, a needle assembly, and a filter member disposed adjacent to the needle assembly. The actuating mechanism is operatively coupled to the syringe assembly and includes a torque spring that exerts a torque to urge the medicament through the filter member to be injected into the user. The actuating mechanism further includes a damper mechanism that exerts an opposing force to dampen the motion exerted by the torque spring.