Force Actuated Injection Device with Adjustable Needle Guard
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Solution Overview
Problem
Current epinephrine auto-injectors are ineffective in delivering accurate doses, particularly in pediatric patients and those with small body mass, due to inadequate needle length and dosing options, leading to potential overdose or underdose during anaphylactic events, and are costly and cumbersome for self-administration.
Innovation Solution
A force-actuated injection device that calibrates dosages and needle length based on patient weight or BMI, allowing for precise, rapid, and safe intramuscular delivery of epinephrine in one continuous motion without stored energy, using a retractable needle guard and resistance band mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard dose auto-injectors (0.15mg or 0.3mg) are used, then device simplicity is maintained, but dosing accuracy deteriorates for pediatric and small body mass patients
Solution Approach 1:
The device incorporates adjustable dosing mechanisms that allow the injection dose to be dynamically changed based on patient weight or body mass index. The needle length and medication volume can be adjusted to match different patient sizes, transforming a static device into an adaptive one that provides precise dosing for both pediatric and adult patients without requiring multiple different devices
Solution Approach 2:
The device allows modification of critical parameters including needle length, medication volume, and injection force. By enabling these parameters to be changed according to patient characteristics, the device achieves accurate dosing across different patient populations while maintaining a single unified device design
2Reliability
If standard needle length is used, then manufacturing simplicity is maintained, but injection effectiveness deteriorates for pediatric and overweight patients
Solution Approach 1:
The device incorporates an adjustable needle length mechanism that allows the needle to be extended or retracted based on patient body mass and injection site requirements. This dynamic adjustment ensures reliable intramuscular delivery for both pediatric patients (shorter needle) and overweight patients (longer needle) while using a single manufacturable needle assembly design
Solution Approach 2:
The needle assembly is divided into separable components including a reusable hub and replaceable needle segments of different lengths. This segmentation allows the base device to be manufactured once, while only the needle segments need to be produced in multiple length variants, significantly reducing overall manufacturing complexity compared to designing entirely different devices
3Device complexity
If force-actuated mechanism without stored energy is used, then device cost is reduced, but operation reliability deteriorates in emergency situations
Solution Approach 1:
The device uses the patient's own injection force as the actuating mechanism. When the patient presses the device against their thigh, their body weight and pressing force automatically trigger the needle extension, plunger activation, and medication delivery sequence. This eliminates the need for external power sources, stored energy mechanisms, or complex electronic controls, reducing cost while ensuring reliable operation during emergencies
Solution Approach 2:
The device is pre-configured with spring-loaded mechanisms and mechanical linkages that are primed and ready to actuate upon application of force. The plunger is pre-loaded with medication, the needle is pre-assembled, and the mechanical triggers are set in their initial positions, so that simply applying pressure initiates the complete injection sequence without requiring additional power or complex 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
The device ensures accurate and rapid delivery of critical care injections, improving safety and effectiveness, particularly in children and small body mass patients, while being cost-effective and easy to use, addressing the limitations of existing auto-injectors.
Implementation Method 1
a resistance band disposed between the body and the needle guard adapted to resist initial needle guard retraction relative to the body, wherein force on the needle guard exceeding a predetermined amount overcomes a frictional force of the resistance band
Data Source
AI summary
A force actuated injection device including a body adapted to contain medication, a grip slidably disposed over the body, a lock disposed between the body and the grip, the lock when locked preventing movement of the grip relative to the body and when unlocked permitting movement of the grip relative to the body, a needle guard retractable relative to the body, a biasing member biasing the needle guard away from the body, and a resistance band disposed between the body and the needle guard adapted to resist initial needle guard retraction relative to the body, wherein force on the needle guard exceeding a predetermined amount overcomes a frictional force of the resistance band allowing the needle guard to retract relative to the body to unlock the grip relative to the body such that movement of the grip relative to the body causes medication to be delivered from the body.