Medicament Injection Device Spring-Driven Needle Retraction
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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 keep the needle separate from the medicament until injection, risking contamination and accidental actuation.
Innovation Solution
A medicament injection device with a main body, needle hub, and needle sleeve, where a compressed spring is used to automatically retract the needle after injection, and a blocking member is removed to initiate needle insertion, ensuring the needle remains separate from the medicament until use, with a cap mechanism to prevent premature activation.
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 and cartridge into a single integrated assembly where the needle is pre-attached to the cartridge in a sterile, sealed configuration. This eliminates the separate needle attachment step while maintaining the handling and storage advantages of cartridge-based systems.
Solution Approach 2:
The needle is pre-assembled and pre-positioned in relation to the cartridge during manufacturing, with sterile barriers in place. This preliminary action eliminates the need for patients to perform needle attachment, resolving the contradiction between ease of manufacture and ease of operation.
2Reliability
If the needle is kept separate from the medicament until injection, then contamination risks are reduced, but additional steps are required for needle attachment
Solution Approach 1:
The needle is nested within a protective sleeve that is integrated with the cartridge assembly. The needle remains protected and separate from the medicament until injection, when the sleeve retracts to expose the needle. This maintains contamination prevention without requiring separate attachment steps.
Solution Approach 2:
A sterile barrier or seal acts as an intermediary between the needle and medicament reservoir, allowing the needle to be pre-positioned and protected while maintaining sterile separation. This resolves the contradiction by enabling integrated design while preserving contamination prevention.
3Ease of operation
If manual needle handling is required, then needle insertion can be controlled, but contamination risks and user difficulty increase
Solution Approach 1:
The device performs needle insertion automatically through a spring-driven mechanism that propels the needle through the skin upon activation. This self-service function eliminates manual needle handling, reducing contamination risk while maintaining user control through simple activation.
Solution Approach 2:
The patent replaces manual mechanical needle insertion with an automated spring-driven mechanism. This substitution eliminates the need for users to manually handle and insert needles, reducing contamination risks while preserving user control through simple activation.
4Reliability
If a spring mechanism is used for automatic needle retraction, then user safety is improved, but device complexity increases
Solution Approach 1:
The device employs a dynamic spring mechanism that automatically propels the needle forward for injection and then retracts it after use. This dynamic system improves user safety by ensuring needle retraction without requiring complex manual操作步骤, as the spring provides automatic reciprocating motion.
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 allows for easy and safe needle insertion into the medicament cartridge without manual handling, reducing contamination risks and preventing accidental actuation, improving user safety and convenience, especially for patients with dexterity issues.
Implementation Method 1
a compressed spring arranged between the needle hub and a distal end of the needle sleeve so that, upon removal of the blocking member, the spring is released, thereby causing the needle hub to move axially in a proximal direction towards the cartridge receiving part
Implementation Method 2
the spring is further configured to cause the needle and the needle hub to retract subsequent to injection of a medicament
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A medicament injection device comprising: a main body (11) having a cartridge receiving part (20) configured to hold a medicament cartridge; a needle holder (25) holding a needle (17); a needle sleeve (24) at least partially surrounding the needle holder and needle and axially movable relative to the main body; a removable transverse blocking member (30) separating the cartridge receiving part and the needle holder; and a compressed spring (27) arranged between the needle holder and a distal end of the needle sleeve so that, upon removal of the blocking member, the spring is released, thereby causing the needle carrier to move axially towards cartridge receiving part.