Medicament Injection Device Rotatable Cap Spring Mechanism
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Solution Overview
Problem
Existing medicament injection devices, particularly those using cartridges, require an additional step for needle attachment, which can be challenging for patients with limited dexterity or coordination, and do not maintain the needle separate from the medicament until injection, compromising sterility.
Innovation Solution
A medicament injection device with a housing, a sleeve, and a rotatable cap assembly that includes a pre-stressed spring mechanism, allowing the needle to be kept separate from the medicament until the cap is rotated, automatically piercing the cartridge's seal to insert the needle, reducing user handling and ensuring sterility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a cartridge is used instead of a syringe, then handling and storage advantages are provided, but an additional needle attachment step is required which complicates operation for patients with limited dexterity
Solution Approach 1:
The patent combines the needle holder and needle assembly with the cartridge housing into a single integrated unit. The needle holder is releasably supported by the cap assembly and automatically docks with the cartridge during the injection process, eliminating the need for separate needle attachment steps while maintaining the cartridge's handling and storage benefits.
2Reliability
If the needle is kept separate from the medicament until injection, then sterility is maintained, but an additional attachment step is required
Solution Approach 1:
The needle holder is pre-assembled with the needle in a sterile state and releasably supported by the cap assembly. The cartridge is also prepared in advance with its sealing member intact. During use, the needle holder automatically docks with the cartridge and the cutting element penetrates the sealing member, maintaining sterility until the moment of injection without requiring manual attachment steps.
3Extent of automation
If a rotatable cap assembly with spring mechanism is used, then automated needle insertion is achieved, but device complexity increases
Solution Approach 1:
The cap assembly incorporates a rotatable cap with a stopping element that interacts with a pre-stressed spring mechanism. When the cap is rotated, the stopping element disengages from the sleeve, releasing the spring to automatically drive the needle holder toward the cartridge. This dynamic mechanism automates the needle insertion process while keeping the structural additions manageable through coordinated movement of existing 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 device simplifies the needle insertion process, reducing user handling and maintaining sterility by automatically inserting the needle into the medicament cartridge upon cap rotation, making it easier for patients with dexterity issues to use while ensuring the needle remains separate until injection.
Implementation Method 1
a pre-stressed spring coupled to the housing and to the sleeve; wherein the cap assembly is arranged so that rotation thereof causes the stopping element to disengage from the sleeve, thereby releasing the pre-stressed spring and causing the sleeve and the medicament cartridge holder to move axially in a distal direction towards the needle
Data Source
AI summary
A medicament injection device is disclosed comprising a housing containing a medicament cartridge holder; a rotatable cap assembly; a needle holder holding a needle, the needle holder being releasably supported by the cap assembly, a pre-stressed spring coupled to the medicament cartridge holder; wherein the cap assembly is arranged so that rotation thereof releases the pre-stressed spring, causing the medicament cartridge holder to move axially in a distal direction towards the needle. A method of operating the device is also disclosed.