Surgical Stapling Firing Lockout Mechanism
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Solution Overview
Problem
Existing surgical stapling apparatuses lack a reliable mechanism to prevent refiring with spent cartridges or without cartridges, leading to potential misuse or inefficiency.
Innovation Solution
A firing lockout assembly with a latch member and biasing member is integrated into the surgical stapling device, allowing advancement of the drive member only when the cartridge is unfired, ensuring the latch member is in an unlocked position, and returning to a locked position when the cartridge is spent or absent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple lockout mechanism is provided to prevent firing with spent cartridges, then the device complexity is reduced, but the reliability of preventing unintended firing is insufficient
Solution Approach 1:
The latch member is nested within the drive member, with the blocking portion integrated into the drive member structure. The latch member pivots within a cavity in the drive member, creating a compact nested arrangement that provides reliable lockout functionality without adding significant external complexity to the device
Solution Approach 2:
The latch member acts as an intermediary mechanical element between the drive member and the firing mechanism. It mediates the firing process by physically blocking the drive member's path when engaged, providing a reliable intermediate control step that prevents unintended firing while maintaining overall device simplicity
2Reliability
If the latch member is positioned to block the stop surface, then firing is prevented, but the drive member cannot advance beyond the initial position
Solution Approach 1:
The latch member is designed as a dynamic, pivotable component rather than a fixed block. It can pivot between a first position where it blocks the stop surface and prevents firing, and a second position where it clears the stop surface and allows drive member advancement. This dynamic positioning enables the system to switch between prevention and operation modes as needed
Solution Approach 2:
The latch member is preliminarily positioned in the blocking position before firing occurs. This preliminary action ensures that the drive member cannot advance unless the latch is first cleared. After firing, the latch member is preliminarily reset to the blocking position to prevent refiring with a spent cartridge, requiring deliberate user action to reset the system
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 solution effectively prevents unintended firing, ensuring the device can only be used with a fresh cartridge, enhancing safety and usability by preventing advancement beyond an initial position without a valid cartridge, thus ensuring reliable operation.
Implementation Method 1
a biasing member positioned to urge the latch member towards the first position
Data Source
AI summary
A surgical stapling device is provided which includes a first jaw supporting an anvil assembly and a second jaw supporting a cartridge assembly. The cartridge assembly supports a firing lockout assembly which includes a latch member having a blocking portion. The latch member is movable between a first position and a second position. In the first position, the blocking portion of the latch member is aligned with the stop surface of the drive member to prevent advancement of the drive assembly beyond an initial advanced position within the tool assembly and in the second position, the blocking member is misaligned with the stop surface of the drive member to permit subsequent advancement of the drive assembly within the tool assembly. In the retracted position of the drive assembly subsequent to firing of the surgical stapling device, the latch member is in the first position.