Pivoting Latch Mechanism for Single-Stroke Lancet Control
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Solution Overview
Problem
Existing lancing devices suffer from excess lancet oscillation, which can cause unintended skin pricks and increased pain due to incorrect balance of spring forces and friction, leading to secondary oscillations.
Innovation Solution
A latch mechanism is introduced to allow a single lancing stroke and prevent subsequent oscillations by engaging the latch after the initial penetration, using a pivotal L-shaped or rotary sleeve-shaped latch member with a resilient finger and ramp system to control the lancet's motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If friction between device components and energy dissipation from lancing are used to dampen lancet oscillation, then some oscillation reduction is achieved, but excess oscillation persists causing unintended skin pricks and increased pain
Solution Approach 1:
A latch mechanism is introduced as an intermediary component between the drive mechanism and the lancet. The latch includes a latch member that can be actuated by a latch actuator and engages with a latch engagement feature on the lancet carrier. This intermediary latch system provides precise control over lancet motion by mechanically preventing further oscillation after the initial lancing stroke, thereby eliminating unintended skin pricks and reducing patient pain while maintaining reliable control over the lancet's single-use function.
2Speed
If spring forces are balanced to achieve correct lancet speed, then pain sensation is reduced, but incorrect balance can cause excess oscillation and unintended skin pricks
Solution Approach 1:
The latch mechanism serves as a mediator that works in conjunction with the spring-based drive mechanism. While the springs provide the necessary force for lancet propulsion and retraction, the latch actuator and latch member work together to control and limit oscillation. The latch engagement feature on the lancet carrier interacts with the movable latch member to mechanically prevent excessive oscillation, thereby complementing the spring force balance and preventing unintended skin pricks while maintaining appropriate lancet speed.
Solution Approach 2:
The latch mechanism introduces dynamic control to the system by allowing the latch member to move between engaged and disengaged states based on the lancing stroke progression. The latch actuator is configured to be actuated during the lancing stroke, dynamically transitioning the latch member to an engaged position that blocks further oscillation. This dynamic adjustment ensures that the lancet maintains correct speed during the initial stroke while preventing excess oscillation in subsequent movements.
3Object-affected harmful factors
If a latch mechanism is added to prevent lancet oscillation, then secondary oscillations are eliminated, but device complexity increases
Solution Approach 1:
The latch mechanism is merged with existing components of the lancing device. The latch actuator is integrated with the drive mechanism or housing, and the latch member is positioned within the existing structural framework. The latch engagement feature is incorporated into the lancet carrier design. By merging the latch system with these existing components, the patent minimizes additional complexity while achieving effective prevention of secondary oscillations and unintended skin pricks.
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 latch mechanism effectively prevents secondary lancet oscillations, reducing pain and ensuring a single, controlled penetration, enhancing user comfort and device efficiency.
Implementation Method 1
a resilient finger extending generally parallel to and transversely offset from the leg and operably engaged and deflected by a ramp
Data Source
AI summary
A lancing device including a latch that pivots between a non-blocking position allowing a lancet carrier and a lancet to advance and retract through a first forward and reverse lancing stroke and a blocking position preventing further/excess/secondary oscillation of the lancet carrier and lancet. The pivotal latch can pivot about an axis perpendicular (e.g., for an L-shaped latch) or parallel/coaxial (e.g., for a sleeve latch) to the advancement and retraction motion of the lancet carrier and lancet.