Lancing Device Activation and Retraction Mechanism
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Solution Overview
Problem
Lancing devices cause significant pain due to the prolonged time the lancet remains in the skin, as the retraction mechanism often requires overcoming the force of the activation spring, leading to a slower and more painful retraction process.
Innovation Solution
An activation/retraction mechanism where the pusher and lancet holder are designed to disengage at the end of the firing stroke, allowing the lancet holder to rapidly return to its initial position without needing to overcome the biasing member's force, utilizing complementary cross-sections and angled or rotational movements to facilitate disengagement and enhance the 'hammer' effect for quicker retraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return spring is used to retract the lancet holder, then the lancet can be reset for reuse, but the retraction time is prolonged due to the need to overcome the activation spring force
Solution Approach 1:
The system is divided into two independent spring mechanisms: the first spring (activation spring) that propels the pusher forward, and the second spring (return spring) that independently manages the lancet holder's retraction. This segmentation allows each spring to perform its specific function without interfering with the other, enabling rapid retraction without needing to overcome the activation spring force.
Solution Approach 2:
The pusher acts as an intermediary component that transfers the activation spring's force to the lancet holder during the lancing stroke, then disengages to allow the return spring to independently control the retraction phase. This intermediary mechanism enables the decoupling of the two spring forces during different operational phases.
2Speed
If the activation spring force is made strong for rapid lancing, then the lancing stroke is powerful and fast, but the retraction becomes slower as the return spring must overcome this strong force
Solution Approach 1:
The spring system is segmented into two independent units with distinct functions: the first spring optimized for rapid forward propulsion during lancing, and the second spring optimized for controlled retraction. This eliminates the conflict where a single spring system would need to balance both opposing requirements.
Solution Approach 2:
The system dynamically switches between two different spring force regimes: during the lancing stroke, the first spring provides strong forward force; during retraction, the second spring provides controlled backward force. This dynamic switching allows optimization for both rapid lancing and fast retraction without compromise.
3Quantity of substance
If the lancet remains in the skin longer to ensure sufficient penetration, then adequate blood sample can be obtained, but the pain experienced by the subject increases
Solution Approach 1:
The lancing mechanism is designed to rapidly penetrate the skin and quickly retract, minimizing the duration of the harmful stimulus. The strong first spring ensures swift penetration through the epidermis to reach capillaries, while the independent second spring enables equally rapid retraction, reducing overall pain exposure time.
Solution Approach 2:
The system changes the temporal parameter of lancet-in-skin duration by using two springs with different force characteristics. The first spring provides high force for rapid penetration, while the second spring enables quick return, thereby reducing the time parameter that directly correlates with pain perception while maintaining sufficient penetration depth.
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 design reduces the time the lancet remains in the skin, minimizing pain and improving the efficiency of the retraction process, thereby enhancing user comfort during blood sampling.
Implementation Method 1
a first biasing member (activation spring) arranged to displace the pusher in a distal direction
Implementation Method 2
a second biasing member (return spring) arranged to displace the lancet holder in a proximal direction
Data Source
Figure 1A~1D
Figure 2A~2E
Figure 3A~3D
AI summary
An activation/retraction mechanism for a lancing device comprising:a pusher (10; 20; 30; 40; 50) comprising a first biasing member (11; 66; 51) arranged to displace the pusher in a distal direction;and a lancet holder (15; 25; 35; 45; 55) comprising a lancet (16) for penetrating the skin of a subject, and a second bi- asing member (17; 47; 57) arranged to displace the lancet holder in a proximal direction; wherein the lancet holder and the pusher are arranged in a housing (12; 42) of the lancing device in such a way that a distal end (13; 23; 33; 43; 53) of the pusher engages a proximal end (18; 28; 38; 48; 58) of the lancet holder to push the lancet holder in a distal direction when the first biasing member dis- places the pusher distally. The distal end of the pusher and the proximal end of the lancet holder are arranged to disengage from each other when the pusher has been displaced distally a predetermined length from its initial posi- tion, whereby the lancet holder may return to its initial position under influ- ence of the second biasing member.A lancing device comprising such an acti- vation/retraction mechanism is also disclosed.