Disposable Lancet Trigger Mechanism for Shortened Needle Exposure
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Solution Overview
Problem
The existing disposable automatic lancets have a too-long-exposed-length of the needle, which increases the force required to screw the protective rod and makes the needle prone to bending during puncture, reducing the puncture performance, especially with finer diameters.
Innovation Solution
The design divides the trigger button's pressing arm into two legs, where the second pressing leg is positioned closer to the needle tip than the first, allowing a safety sleeve to cover the press-down channel, shortening the exposed needle length by adjusting the distance between the legs and the needle tip, and utilizing a self-locking mechanism with a barb and hook for safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the exposed length of the needle is reduced, then the needle is less prone to bending during puncture and the force required to screw the protective rod is reduced, but the trigger button structure becomes more complex
Solution Approach 1:
The trigger button is divided into two separate pressing legs: a first pressing leg that acts on the elastic arm to enable needle ejection, and a second pressing leg that acts on the safety sleeve to enable self-locking. This segmentation allows each leg to perform its specific function independently, achieving the desired needle length control without requiring a completely redesigned trigger mechanism.
Solution Approach 2:
The safety sleeve serves as an intermediary component between the second pressing leg and the needle core. It translates the pressing action of the second pressing leg into the self-locking function by engaging with the barb, while also serving as a positioning element that controls the exposed needle length. This intermediary approach allows for precise control of needle exposure without direct manipulation of the needle core itself.
2Object-affected harmful factors
If the needle diameter is made finer to reduce algesia, then patient comfort is improved, but the needle becomes more prone to bending during puncture
Solution Approach 1:
The safety sleeve is designed to cover the needle tip and occupy the press-down channel in the assembled state, preliminarily preventing any potential bending or displacement of the fine needle before the puncture operation begins. This preliminary protective action is particularly important for fine-gauge needles that are more susceptible to bending.
Solution Approach 2:
The invention changes the geometric parameters of the trigger button structure by introducing two pressing legs at different positions and distances from the needle tip. This parameter adjustment allows for precise control of the exposed needle length, which in turn stabilizes fine-gauge needles during puncture while maintaining the fine diameter necessary for reducing algesia.
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
This solution shortens the exposed needle length by at least 4 mm, enhances puncture strength, and allows for the use of finer needles, making the lancet easier to use and reducing bending during puncture.
Implementation Method 1
a spring (3) arranged on the other end of the needle core (2) to form an ejection structure where the spring (3) pushes the needle core (2) to move
Implementation Method 2
An elastic arm (8) for locking the needle core (2) is extending from the bottom wall of the lower cover (16) of the housing (1) to the ejection chamber (5)
Implementation Method 3
the barb (12) and the self-locking hook (13) forms a self-locking fit
Data Source
AI summary
An improved safe and convenient disposable automatic lancet, comprising a housing (1), a needle core (2), a spring (3) and a protective rod (4), wherein, a pressing arm of a trigger button (10) is divided into a first pressing leg (11) and a second pressing leg (19), and the first pressing leg (11) is used for triggering an elastic arm in a locking structure to form a press-type trigger structure, and the second pressing leg (19) fits with a safety sleeve (20) and a press-down channel (17) to achieve a safety function of the trigger button (10); a barb (12) on the second pressing leg (19) fits with a self-locking hook (13) on the housing (1) so as to achieve a self-locking function after one press. In order to shorten the exposed needle length of a needle body on the needle core (2), in the automatic lancet, the distance between the second pressing leg (19) and the needle tip (7) is designed to be less than the distance between the first pressing leg (11) and the needle tip (7). Since the exposed needle length depends on the position of the safety sleeve (20), the exposed needle length is shortened, therefore the puncture performance increases, which enables the design of the lancet to be more reasonable and practical.