Surgical Stapling Lockout Mechanism for Preventing Improper Firing
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Solution Overview
Problem
Existing surgical stapling devices lack a mechanism to prevent the advancement of the drive assembly when the actuating sled or staple cartridge is missing or spent, leading to complications such as cutting of tissue without stapling.
Innovation Solution
A lockout mechanism is implemented, featuring a lockout member and an interlock spring that moves between relaxed and flexed conditions to prevent the drive assembly's advancement when the actuation sled is absent or in a spent position, using a ramp feature to engage the lockout member and a retraction ramp to return to the relaxed condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no lockout mechanism is present, then the drive assembly can advance freely, but this causes tissue cutting without stapling when the actuating sled is missing or spent
Solution Approach 1:
The lockout member is positioned in advance to block the drive assembly's path before firing can occur. When the actuating sled is absent or spent, the lockout member remains in a blocking position, preventing the drive assembly from advancing and thus preventing improper firing before the condition can be detected
Solution Approach 2:
The lockout member acts as an intermediary element between the drive assembly and the actuating sled. It mediates the interaction by physically blocking the drive assembly when the actuating sled is missing or spent, providing a mechanical safety function without requiring complex electronic or sensing systems
2Reliability
If the lockout member blocks drive assembly advancement, then tissue damage is prevented, but the drive assembly cannot advance to perform stapling when the actuating sled is present
Solution Approach 1:
The lockout member transitions from a static blocking position to a dynamic released position based on the presence and movement of the actuating sled. When the actuating sled is properly installed and advances, it interacts with the lockout member to move it out of the blocking path, allowing the drive assembly to advance and perform stapling efficiently
Solution Approach 2:
The lockout mechanism applies a preliminary blocking action that is automatically removed when the actuating sled is properly installed. This preliminary anti-action prevents improper firing while maintaining the capability for efficient stapling operation when conditions are correct
3Reliability
If the lockout member is always in blocking position, then drive assembly advancement is always prevented, but stapling function cannot be performed
Solution Approach 1:
The lockout member dynamically changes its position based on the state of the actuating sled. It maintains a blocking position when the sled is absent or spent to prevent undesired advancement, but automatically moves to a non-blocking position when the sled is properly installed and advances, allowing smooth operation
4Reliability
If the lockout mechanism uses complex components, then reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The lockout mechanism applies quality and complexity only where necessary - specifically in the lockout member and its interaction with the actuating sled. The rest of the drive assembly remains simple and straightforward, allowing reliable lockout function without overall device complexity
Solution Approach 2:
The lockout member utilizes changes in physical parameters such as position, engagement state, and mechanical interaction forces to achieve reliable lockout function. By changing its position from blocked to non-blocked based on simple mechanical parameters rather than complex electronic signals, the system achieves reliability without complexity
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 undesired advancement of the drive assembly, ensuring proper stapling operation by preventing the drive assembly from moving when the actuation sled is missing or the cartridge is spent, thereby reducing tissue damage and complications.
Implementation Method 1
an interlock spring secured to the channel member and movable between a relaxed condition and a flexed condition
Data Source
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AI summary
A tool assembly includes a cartridge assembly and an anvil assembly pivotally secured to the cartridge assembly and movable between open and clamped positions. The cartridge assembly includes a channel member, a staple cartridge supported in the channel member, and an actuation sled positioned within the staple cartridge. The actuation sled is movable from a first position to a second position to eject staples from the staple cartridge. The tool assembly further includes a drive assembly having a clamping member movable from an initial position to an advanced position to move the actuation sled from the first position to the second position, and a lockout member secured to the channel member and moveable between a relaxed condition and a flexed condition. Movement of the actuation sled from the first position towards the second position causes the lockout member to move to the flexed condition to permit advancement of the drive assembly.