Injection Drive Dual Gear Patterns Prevent Accidental Discharge
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Solution Overview
Problem
Existing injection devices for medicaments lack a simple and efficient design that allows patients to set and administer precise dosages without accidental medicament discharge during dosage setting.
Innovation Solution
An injection device with a drive member having fixed gear patterns, a plunger for medicament expulsion, and a dosage indicator system, where the drive member is rotatable and translatable to set and deliver dosages, featuring a one-way clutch and non-unitary gear ratio to prevent accidental medicament discharge and provide clear dosage feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple drive mechanism is used for dosage setting, then device complexity is reduced, but accidental medicament discharge cannot be prevented
Solution Approach 1:
The drive member is designed to perform different types of movement depending on the operational phase: rotational movement during dosage setting and axial translation during medicament delivery. This dynamic behavior is enabled by the interaction between the gear pattern and the one-way clutch mechanism, which automatically switches the movement mode based on the operational state, thus preventing accidental discharge while maintaining simplicity.
Solution Approach 2:
A one-way clutch is introduced as an intermediary element between the drive member and the plunger. This clutch allows axial translation of the drive member to be transmitted to the plunger for medicament delivery, but prevents reverse transmission that would cause accidental discharge during dosage setting. The one-way clutch thus mediates the power transmission in a controlled manner.
2Ease of operation
If the drive member is rotatable for dosage setting, then ease of operation is improved, but accidental medicament discharge may occur
Solution Approach 1:
The system dynamically switches between rotational and axial movement modes. During dosage setting, the drive member rotates freely to adjust the dosage without transmitting force to the plunger. During delivery, the drive member translates axially to push the plunger. The one-way clutch automatically enables or disables the rotational-to-axial power transmission based on the operational phase, preventing harmful accidental discharge while maintaining ease of dosage setting.
Solution Approach 2:
The harmful function of rotational movement causing accidental discharge is extracted and isolated from the dosage setting operation. The one-way clutch disconnects the rotational movement from plunger actuation during setting, allowing only the desired dosage adjustment function to occur without the harmful side effect of unintended medicament delivery.
3Adaptability or versatility
If gear patterns are added to the drive member, then functionality is improved, but device complexity increases
Solution Approach 1:
The drive member is designed as a multi-functional component that combines both dosage setting (rotational) and medicament delivery (axial translation) capabilities within a single mechanism. The gear pattern on the drive member interacts with both the one-way clutch and the plunger, enabling one component to perform multiple functions rather than requiring separate mechanisms for each operation.
Solution Approach 2:
The gear pattern and one-way clutch mechanism are merged into an integrated system where the gear teeth directly engage with the clutch mechanism. This combination eliminates the need for separate control mechanisms for dosage setting and delivery, reducing the overall number of components while maintaining full functionality. The gear pattern serves dual purposes: enabling rotational dosage adjustment and facilitating axial power transmission.
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 enables patients to set and deliver precise medicament dosages efficiently, preventing accidental discharge during dosage setting and providing clear visual feedback on remaining dosage, thus enhancing user safety and operational simplicity.
Implementation Method 1
a one-way clutch operably coupled with the first rotatable gear member wherein the one-way clutch prevents rotation of the first gear member when the drive member is rotated in the first rotational direction
Implementation Method 2
a first gear pattern with a first gearing arrangement operably coupling the first gear pattern with the plunger
Implementation Method 3
The first gear pattern may also advantageously define a worm gear
Data Source
AI summary
An injection device having a drive member with first and second gear patterns that are fixed relative to each other. The drive member is rotatable and translatable in first and second opposing axial directions. A plunger expels medicament from a cartridge when it is translated in an advancing direction. A dosage indicator indicates a set dosage. A first gearing arrangement operably couples the first gear pattern with the plunger wherein rotation of the drive member in a first direction translates the drive member in a first axial direction without movement of the plunger and translation of the drive member in the opposite axial direction drives the plunger in the advancing direction. A second gearing arrangement operably couples the second gear pattern with the dosage indicator and moves the dosage indicator to indicate an increase in the set dosage when the drive member is translated in the first axial direction.