Staple Cartridge Lockout Lever for Surgical Stapler Firing Control
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Solution Overview
Problem
Existing surgical staplers lack effective mechanisms to prevent inadvertent firing when the staple cartridge is empty or improperly installed, leading to improper staple formation and tissue cutting without stapling.
Innovation Solution
A cartridge-based firing lockout mechanism featuring a pivotable lockout lever that ensures the pusher member is prevented from actuating when the staple cartridge is empty or improperly seated, using camming surfaces to transition between locked and unlocked states based on the presence of a compatible cartridge and wedge sled position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a firing lockout mechanism is implemented to prevent inadvertent firing, then safety and reliability are improved, but device complexity increases
Solution Approach 1:
The lockout lever is nested within the cartridge assembly, with the lockout lever (164) positioned inside the cartridge (154) and interacting with the wedge sled (170) that is also nested within the cartridge. This nesting approach integrates the safety mechanism into the existing cartridge structure rather than adding external components, thereby improving reliability while minimizing the increase in device complexity.
Solution Approach 2:
The lockout mechanism operates automatically based on the physical state of the cartridge and wedge sled positioning. The camming surfaces (165, 180) automatically engage or disengage the lockout lever from the catch surface (352) depending on whether the cartridge is properly installed and the wedge sled is in the correct position, eliminating the need for external control systems or additional actuators.
2Manufacturing precision
If camming surfaces are used to control lockout state transitions, then precision of firing control is improved, but manufacturing precision requirements increase
Solution Approach 1:
The camming surfaces (165, 180) utilize curved geometric profiles that naturally guide the lockout lever through precise angular transitions as the wedge sled moves linearly. The curved geometry of the camming surfaces converts linear motion of the wedge sled into rotational motion of the lockout lever, providing smooth and reliable engagement/disengagement of the locking state without requiring high-precision manufacturing tolerances.
Solution Approach 2:
The camming surfaces employ asymmetric geometric profiles where the engagement surface (165) and disengagement surface (180) have different orientations and angles. This asymmetry ensures unidirectional control of the lockout mechanism, allowing the lever to be engaged in a specific direction while requiring a different mechanical action for disengagement, thereby providing precise firing control through geometric design rather than complex control systems.
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
Prevents inadvertent firing, ensuring proper staple formation and tissue stapling by maintaining alignment between the staple cartridge and anvil, thereby enhancing surgical precision and safety.
Implementation Method 1
A cartridge-based firing lockout mechanism features a pivotable lockout lever that ensures the pusher member is prevented from actuating when the staple cartridge is empty or improperly seated, using camming surfaces to transition between locked and unlocked states
Data Source
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AI summary
A surgical stapling instrument includes a shaft assembly and an end effector. The end effector includes a first jaw having an anvil, a second jaw configured to removably receive a staple cartridge, and a driving assembly translatable distally through the second jaw for pivoting the second jaw toward the first jaw to clamp tissue between the first jaw and the second jaw. The instrument also includes a lockout mechanism configured to transition between a first state in which the lockout mechanism prevents distal translation of the driving assembly through the second jaw, and a second state in which the lockout mechanism permits distal translation of the driving assembly through the second jaw. The lockout mechanism is configured to transition from the first state to the second state when the staple cartridge is removably received by the second jaw.