Safety Injection Device with Irreversible Slider Mechanism
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Solution Overview
Problem
Traditional insulin injection devices are prone to cross-infection due to lack of immediate protective structures after use, and existing safety needles often have high manufacturing and use costs, increased operational difficulty, and risk of incomplete injections due to needle length and tissue thickness issues.
Innovation Solution
A safety injection device with a needle, slider, needle shield, protective sleeve, and elastic member, where the slider rotates irreversibly after use, ensuring the needle is protected and preventing reuse, featuring a guide structure and colored indicator for used status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective structure is added to protect the needle tip immediately after injection, then cross-infection risk is reduced, but device complexity increases
Solution Approach 1:
The protective sleeve is nested within the needle shield structure, and the slider is integrated into the needle shield. This nested arrangement allows multiple protective and functional components to occupy the same spatial envelope, providing immediate post-injection protection without significantly increasing the overall device footprint or complexity
Solution Approach 2:
The protective sleeve is pre-positioned within the needle shield before use. Upon injection completion, the spring automatically propels the protective sleeve forward to cover the needle tip immediately, without requiring additional user actions. This preliminary positioning ensures instant protection while maintaining a simple operational interface
2Reliability
If a slider rotation mechanism is added to prevent reuse, then safety is improved, but manufacturing cost increases
Solution Approach 1:
The slider features an asymmetric profile with a rounded end and a flat end,配合 the corresponding asymmetric guide structure in the needle shield. This asymmetric design creates irreversible rotation - the slider can rotate in one direction but cannot return to its initial position, providing clear single-use indication. The asymmetric geometry is simple to manufacture using standard machining processes
Solution Approach 2:
The slider acts as an intermediary component between the protective sleeve and the needle shield. It translates the linear motion of the protective sleeve into rotational motion, and its position serves as a visual indicator of device usage status. This intermediary mechanism provides reliable single-use verification without complex electronics or additional cost-intensive components
3Reliability
If a needle shield and protective sleeve are added, then needle protection is improved, but injection resistance increases
Solution Approach 1:
The needle shield and protective sleeve are designed to move dynamically during the injection process. The protective sleeve is initially retracted to allow needle penetration, then automatically advances after injection to provide protection. This dynamic configuration minimizes resistance during the critical injection phase while ensuring protection afterward
Solution Approach 2:
The protective system is segmented into two functional parts: the needle shield that protects the needle shaft and provides structural support, and the protective sleeve that covers the needle tip. This segmentation allows each component to be optimized for its specific function - the shield maintains a sleek profile for low resistance, while the sleeve provides tip protection only when needed
4Reliability
If spring and slider mechanisms are added, then operational safety is improved, but ease of operation deteriorates
Solution Approach 1:
The spring mechanism is pre-loaded and automatically activates after injection to propel the protective sleeve forward and rotate the slider. The device performs its own safety actions without requiring additional user manipulation, buttons, or complex sequencing. Users simply complete the injection and the safety mechanism self-activates, maintaining ease of operation while ensuring safety
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 single-use safety, prevents cross-infection, reduces operational difficulty, and provides a cost-effective solution with a simple and intuitive design that immediately protects the needle after use, making it safer and more convenient for patients.
Implementation Method 1
an elastic member, being sleeved on the needle with the needle as a shaft, and a distal end of the elastic member being in contact with a proximal end of the slider
Data Source
AI summary
The present application discloses a safety injection device including a needle, a needle hub, an elastic member, a slider, a needle shield, a protective sleeve, and an outer cover. The needle hub, the elastic member, the slider, the needle shield and the protective sleeve are sleeved in sequence with the needle as a shaft. The slider is configured to rotate irreversibly after a single use. The safety injection device according to the present application has a simple and reasonable structure, and is safe, stretchable, and easy to use. In addition, it avoids fear of the needle tip during injection when use. After use, the injection device utilizes the eccentric principle to prevent from being fully depressed again, and the needle tip will not be exposed again, thereby more effectively avoiding the risk of cross infection caused by accidental contact with the needle tip after use.