Circular Stapler Breakaway Washer Blade Retention

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Solution Overview

Problem

Reusable circular stapling instruments pose a hazard due to exposed sharp edges when not properly secured after use, and existing designs rely on unreliable friction to cover the annular blade knife edge, risking accidental reuse and user safety.

Innovation Solution

A breakaway washer attachment mechanism is integrated into the circular stapling instrument, where a blade with a breakaway washer attachment member is attached to the staple driver, ensuring the breakaway washer is not cut until the instrument is fired, thereby securely locking the blade and preventing accidental reuse by attaching to the cut washer, which also serves as a protective barrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a solid cutting board is used to cover the annular blade knife edge, then the blade is protected, but the cover may separate from the blade exposing the sharp edge

Engineering Contradiction:
Improveblade coverage reliabilityVSAvoidretention mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cutting board is divided into a solid cutting board and a separate breakaway washer. The breakaway washer is attached to the blade via retention barbs, while the cutting board covers the blade. This segmentation allows the breakaway washer to remain attached to the blade even when the cutting board is removed, maintaining reliable coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The breakaway washer is pre-positioned on the blade with retention barbs engaged before use. This preliminary attachment ensures that when the cutting board is removed after use, the breakaway washer remains attached to the blade, providing continuous protection of the sharp edge.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the annular blade is left in an advanced position after use, then the instrument can be reused, but the sharp edge is exposed posing a hazard

Engineering Contradiction:
Improveinstrument reusabilityVSAvoidexposed sharp edge hazard
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The breakaway washer is designed as a disposable component that remains attached to the blade after use. When the instrument is disposed of or the blade is replaced, the breakaway washer is discarded with it, ensuring the sharp edge is always covered. This eliminates the hazard of exposed sharp edges while allowing instrument reuse.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The breakaway washer acts as an intermediary between the blade and the external environment. It provides a physical barrier that covers the sharp edge, mediating the interaction between the blade and anything that might contact it, thereby eliminating the hazard of exposed sharp edges.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If friction is used to retain the cutting board over the annular blade, then the structure is simple, but the retention is unreliable

Engineering Contradiction:
Improveretention mechanism simplicityVSAvoidcutting board retention
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The retention system is segmented into retention barbs on the breakaway washer that engage with corresponding features on the blade. This mechanical interlocking provides reliable retention without complex mechanisms, as the barbs physically prevent the breakaway washer from detaching.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2524655B1Circular stapling instrument having a breakaway washer attachment member
Publication Date: 2016.06.29 ETHICON ENDO SURGERY INC
  • EP2524655B1 patent drawingFigure 1
  • EP2524655B1 patent drawingFigure 2
  • EP2524655B1 patent drawingFigure 3A~3B

AI summary

A stapling cartridge assembly for a circular stapling instrument includes a casing, a staple driver, and a blade. The staple driver is receivable within the casing and configured to move within the casing from a pre-fired position to a fired position. The blade is attachable to the staple driver. The blade includes a cutting edge and a breakaway washer attachment member for fixedly attaching to a breakaway washer when the staple driver is moved from the pre-fired position to the fired position.