Stapling Device Biasing Member Separates Knife and Cut Ring
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Solution Overview
Problem
Existing circular stapling devices face issues where the annular knife sticks to the cut ring after firing, preventing the anvil head from tilting and being removed, due to the difference in material hardness causing the cut ring to return to its initial position instead of facilitating the movement to a tilted position.
Innovation Solution
A shell assembly with a biasing member, such as a coil spring, is integrated to separate the annular knife and cut ring after firing, ensuring the cut ring moves to an advanced position and preventing sticking, allowing the anvil head to tilt and facilitating device removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cut ring is formed from a softer material than the annular knife, then the annular knife can penetrate the cut ring during firing, but the annular knife sticks to the cut ring after firing and the cut ring returns to its first position
Solution Approach 1:
The biasing member is pre-configured to exert a separating force on the cut ring before the annular knife retracts. This preliminary anti-action counteracts the sticking tendency between the knife and cut ring, ensuring the cut ring remains in the second position and preventing the problem of returning to the first position after firing.
Solution Approach 2:
The biasing member acts as an intermediary element between the cut ring and the annular knife system. It mediates the interaction by providing a controlled separating force that prevents direct sticking between the knife and cut ring, while still allowing the knife to penetrate the cut ring during firing operation.
2Stability of the object's composition
If the cut ring is held in the first position to prevent anvil head tilting, then the anvil head remains stable during operation, but the anvil head cannot tilt to the tilted position for device removal
Solution Approach 1:
The system transitions from a static position control mechanism to a dynamic one. The biasing member allows the cut ring to move between the first and second positions based on operational requirements. During firing, the cut ring is in the first position for stability; after firing, the biasing member pushes it to the second position, enabling anvil head tilting for easy removal.
Solution Approach 2:
The biasing member is pre-configured to automatically push the cut ring to the second position after the firing sequence completes. This preliminary action ensures that when the annular knife retracts, the cut ring is already positioned to allow anvil head tilting, facilitating seamless device removal without requiring additional manual intervention.
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 biasing member effectively separates the annular knife and cut ring, enabling the anvil head to tilt and facilitating the removal of the stapling device from the patient by minimizing the likelihood of the cut ring sticking to the knife, thus overcoming the sticking issue and ensuring proper device removal.
Implementation Method 1
a biasing member supported within the housing. The biasing member has a proximal portion and a distal portion... The biasing member extends to a position distally of the annular knife when the annular knife is in the retracted position
Data Source
Figure 1
Figure 2~2A
Figure 3
AI summary
A circular stapling device (10) includes a shell assembly (20) and an anvil assembly (16). The shell assembly includes a housing (40), a staple cartridge supported on the housing, an annular knife (62) supported within the housing, and a biasing member (64) supported within the housing. The anvil assembly includes a center rod and an anvil head that supports a cut ring (33) that is axially aligned with the annular knife. The biasing member is positioned within the housing and extends to a position distally of the annular knife when the annular knife is in the retracted position to shield the annular knife. The anvil assembly is movably supported in relation to the shell assembly between an unapproximated position and an approximated position, wherein in the approximated position, the biasing member is engaged with the cut ring and urges the cut ring in a distal direction.