Injection Device Velocity Regulator for Syringe Impact
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Solution Overview
Problem
Autoinjectors face issues where the force exerted by the insertion spring during needle insertion can damage the syringe when it bottoms out, and there is a need to regulate the velocity of the plunger to prevent impact and ensure smooth medicament delivery.
Innovation Solution
The injection device incorporates a velocity regulator with a screw thread and thread-engaging members to control the plunger's velocity during insertion and disengagement, ensuring controlled movement and preventing damage to the syringe, while a release mechanism allows the delivery spring to fully actuate for medicament delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the insertion spring exerts force to move the syringe during needle insertion, then the needle insertion function is achieved, but the syringe may be damaged when it bottoms out against the housing
Solution Approach 1:
The velocity regulator is positioned to engage the plunger before the syringe reaches the bottomed-out position, gradually reducing the plunger's velocity and cushioning the impact before contact occurs. This prevents sudden shock forces that would damage the syringe or housing.
Solution Approach 2:
The velocity regulator acts as an intermediary mechanism between the insertion spring and the syringe-plunger assembly. It mediates the force transmission by controlling velocity, preventing direct transmission of harmful impact forces to the syringe.
2Productivity
If the plunger moves quickly through the syringe to deliver medicament, then the delivery speed is improved, but impact damage may occur during the transition from insertion to delivery phase
Solution Approach 1:
The velocity regulator provides beforehand cushioning by controlling the plunger's acceleration and velocity during the transition phase. It ensures the plunger reaches the delivery position at a controlled speed, preventing impact damage while maintaining efficient medicament delivery.
Solution Approach 2:
The velocity regulator dynamically adjusts the plunger's velocity during different phases of operation. During insertion, it limits speed to prevent damage; during delivery, it allows full spring force to actuate the plunger at optimal speed for medicament ejection.
3Object-affected harmful factors
If the velocity regulator is added to control plunger movement, then syringe damage is prevented, but the device complexity increases
Solution Approach 1:
The velocity regulator is merged with the existing plunger and sleeve structure. The screw thread is formed on the plunger itself, and the thread-engaging members are integrated into the sleeve, combining multiple functions into unified components rather than adding separate discrete parts.
Solution Approach 2:
The sleeve serves multiple functions: it guides the plunger during insertion, houses the thread-engaging members for velocity regulation, and transitions to allow full plunger actuation during delivery. This multi-functionality reduces the need for additional dedicated components.
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 velocity regulator effectively limits the plunger's initial velocity, preventing syringe damage and ensuring smooth needle insertion, while allowing the full force of the delivery spring to be applied for efficient medicament delivery, enhancing the safety and efficacy of the autoinjector.
Implementation Method 1
The velocity regulator comprises a screw thread associated with one of the sleeve and the plunger and one or more thread engaging members formed on the other of the sleeve and the plunger
Implementation Method 2
an insertion spring biasing the sleeve relative to the housing, and a delivery spring biasing the plunger relative to the sleeve
Data Source
Figure 1
Figure 2
Figure 3(A)~3(C)
AI summary
An injection device for delivering a medicament from a syringe contained, in use, within a housing of the device, the device being configured to move the syringe through the housing to cause insertion of a needle of the syringe into a user's skin and to subsequently move a bung of the syringe through a syringe body to deliver medicament through the needle. The device comprises a plunger for engaging with said bung, a sleeve located around the plunger, an insertion spring biasing the sleeve relative to the housing, and a delivery spring biasing the plunger relative to the sleeve. The device further comprises a release mechanism for releasing the sleeve from the housing to commence insertion and for releasing the plunger from the sleeve, following insertion, to commence delivery of the medicament, and a velocity regulator for regulating the velocity of the plunger upon its release from the sleeve and for disengaging from the plunger during delivery, the velocity regulator comprising a screw thread associated with one of the sleeve and the plunger and one or more thread engaging members formed on the other of the sleeve and the plunger.