Double-Swing-Arm Lancet Mechanism for Infant Blood Sampling
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Solution Overview
Problem
Existing incision lancets face challenges in accurately controlling incision depth and width, particularly for blood collection from infants' heels, due to limitations in the mechanism design.
Innovation Solution
A disposable incision safety lancet featuring a cam-driven double-swing-arm mechanism with a blade that follows a V-formed path, allowing for adjustable incision depth and width by varying the radii of the cam's curved surface and swing arm dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single blade with supporting arm and copying track slot is used, then the structure is simple and movement is reliable, but the incision depth and width cannot be accurately controlled
Solution Approach 1:
The single blade supporting arm is segmented into two independent swing arms (first swing arm and second swing arm), each capable of independent oscillation. The first swing arm oscillates along a first copying track slot while the second swing arm oscillates along a second copying track slot, allowing separate control of incision depth and width parameters
Solution Approach 2:
A blade connecting piece is introduced as an intermediary component to connect the first and second swing arms. This connecting piece transmits the oscillation from the first swing arm to the second swing arm through a connecting rod, enabling coordinated control of both incision depth and width while maintaining structural simplicity
2Device complexity
If the blade movement track is arc-shaped, then the mechanism is simple, but it is difficult to control incision depth within 0.5-2 mm and width within 2.5-3 mm
Solution Approach 1:
The single arc-shaped movement track is segmented into two separate copying track slots with different orientations. The first copying track slot controls the incision depth parameter while the second copying track slot controls the incision width parameter, allowing precise control within the required ranges
Solution Approach 2:
The movement control is extended from a single-dimensional arc track to a two-dimensional coordinated system with two perpendicular copying track slots. This dimensional expansion enables independent control of both incision depth and width parameters simultaneously
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 double-swing-arm design enhances control and accuracy over incision depth and width, enabling precise blood collection suitable for infants' heels, surpassing the limitations of single-swing-arm structures.
Implementation Method 1
the spring, as a driving element of the incision blood-taking mechanism, is positioned between the cam and the casing, and acts on the rotary direction of the cam
Implementation Method 2
the spring...acts on the rotary direction of the cam...the cam is rotatably fixed in the casing via a pivot
Implementation Method 3
The flange of the cam is provided, corresponding to this working face, with a curved surface, whose curvature radius is transient from a first radius (R1) to a second radius (R2); this curved surface forces the main swing arm to make a first swing with rotation of the cam
Implementation Method 4
the point of the blade is swingingly stretched out of the casing from the blood-taking opening along a first arc-shaped path (A); when the incision blood-taking mechanism makes the second swing, the point of the blade is swingingly retracted into the casing along a second arc-shaped path (B)
Data Source
AI summary
A disposable incision safety lancet is provided, including a casing (2) and a trigger. It is characterized in that the casing (2) is provided inside with an incision blood-taking mechanism composed of a cam (3), a main swing arm (4), a secondary swing arm (5), a blade (1) and a spring (8). The present invention combines the two arc-shaped tracks obtained from the two swing mechanisms, the main swing arm and the secondary swing arm, via the cam and a toggle pin provided on the cam effectively and interlockingly, thus making the point of the blade incise along a V-formed path composed of two arcs of different shape connected with each other. Compared with the prior art single-swing-arm structure of the incision blood-taking mechanism, such a double-swing-arm structure can move with higher accuracy and controllability. An incision of different blood-taking depth and blood-taking width can be designed by means of changing the difference of change of the radius of curvature of the flange of cam (3) as well as changing the swing radius of the main swing arm (4) and the secondary swing arm (5), which is especially suitable for taking blood from infants' heel.