Fixed-Dose Medicament Delivery Device with Rotational Guide Sleeve
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Solution Overview
Problem
Conventional injection devices, both manual and autoinjectors, pose challenges for users, particularly the elderly and those with dexterity issues, as they require continuous force and precise alignment, which can lead to incomplete dosing and increased risk of needlestick injuries.
Innovation Solution
A fixed-dose medicament delivery device featuring a housing with a safety sleeve, guide sleeve, and plunger mechanism, where the safety sleeve is biased to cover the needle and can be retracted to expose it, allowing for easy alignment and automatic dosing through a button-activated rotational mechanism that advances the plunger to deliver predetermined doses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a manual injection device with button/plunger is used, then the user can control the injection process, but the user must continuously apply force and maintain dexterity which may be too difficult for elderly or arthritic patients
Solution Approach 1:
The injection device is designed to perform the injection automatically without requiring continuous user intervention. The spring mechanism self-activates to push the plunger, and the device maintains injection pressure automatically, allowing the user to simply trigger the device and hold it in place without continuously pressing or adjusting anything.
Solution Approach 2:
The spring is pre-loaded during device assembly or prior to use, storing the force needed for injection in advance. This preliminary action eliminates the need for the user to apply force during the actual injection, as the spring is already prepared to deliver the required pressure automatically when triggered.
2Force
If a conventional autoinjector with spring mechanism is used, then the injection force is provided automatically, but the device complexity increases with additional components like trigger buttons and activation mechanisms
Solution Approach 1:
The trigger button and safety mechanism are combined into a single integrated component. The button serves dual purposes: it activates the spring mechanism for injection and simultaneously releases the safety feature that prevents accidental activation. This merging reduces the number of separate parts and simplifies the overall device structure.
Solution Approach 2:
The button mechanism performs multiple functions: it acts as the activation trigger for the spring, serves as a safety release mechanism, and provides user feedback through its movement. This multi-functionality reduces the need for separate components, thereby reducing device complexity while maintaining automatic force delivery.
3Object-affected harmful factors
If the safety sleeve is extended to cover the needle, then needlestick risks are reduced, but the needle alignment and exposure require additional user dexterity
Solution Approach 1:
The safety sleeve is designed to automatically move with the needle assembly during the injection process. As the needle is inserted and the injection proceeds, the safety sleeve automatically retracts or positions itself, eliminating the need for the user to manually adjust or align the safety feature. The device self-manages the safety sleeve positioning.
Solution Approach 2:
The safety sleeve is nested around the needle assembly, allowing it to move in conjunction with the needle. This nested configuration ensures that the safety sleeve automatically follows the needle's position and movement, providing continuous protection without requiring separate alignment actions by the user.
4Measurement precision
If a fixed-dose delivery mechanism is used, then predetermined doses are delivered reliably, but the device requires a rotational mechanism that adds structural complexity
Solution Approach 1:
The rotational mechanism for dose control is merged with the plunger advancement mechanism. The same rotational motion that controls the dosing also directly drives the plunger forward, eliminating the need for a separate dosing mechanism. This integration reduces structural complexity while maintaining precise fixed-dose delivery.
Solution Approach 2:
The guide sleeve serves multiple functions: it guides the plunger movement, controls the rotational motion for dosing, and interfaces with the spring mechanism. This multi-functionality reduces the number of dedicated components needed for each function, thereby reducing overall structural complexity while ensuring precise fixed-dose 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 device simplifies the injection process by reducing the force required and ensuring complete dosing, while the safety sleeve mitigates needlestick risks and provides feedback for empty cartridges, enhancing user safety and ease of use.
Implementation Method 1
a plunger spring biasing the plunger relative to the housing
Implementation Method 2
a safety sleeve spring biasing the safety sleeve toward the extended position
Data Source
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AI summary
Described is a medicament delivery device comprising a housing (102), a safety sleeve (106) movable between an extended position and a retracted position relative to the housing (102), a guide sleeve (114) rotatably disposed in the housing (102), a plunger (110) slidably disposed in the safety sleeve (106), and a button (126) coupled to the housing (102). When the safety sleeve (106) is in the retracted position, translation of the button (126) relative to the housing (102) causes the guide sleeve (114) to rotate relative to the safety sleeve (106). Rotation of the guide sleeve (114) relative to the safety sleeve (106) allows the plunger (110) to translate a predetermined axial distance relative to the safety sleeve (106).