Replaceable Surgical Scissor Blades With Over-Center Pulley Access
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Solution Overview
Problem
Existing robotic surgical instruments with end effectors, such as surgical scissors, face issues due to high-wear components that degrade over time, limiting their useful life and affecting efficiency.
Innovation Solution
A system for easily replacing the blades of surgical scissors by rotating actuation pulleys to an over-centered position, exposing the actuation bosses for quick removal and installation of new blades, extending the end effector's life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surgical scissor blades are used continuously, then productivity is maintained, but the blades dull over time and reliability deteriorates
Solution Approach 1:
The surgical scissor is divided into replaceable blades and a stationary handle assembly. The blades can be independently removed and replaced when dull, while the handle and drive mechanism remain intact. This segmentation allows the high-wear cutting components to be replaced without discarding the entire instrument.
Solution Approach 2:
The patent implements a blade replacement system where dull blades are removed and new blades are installed in the same end effector housing. The drive cables and actuation mechanisms are recovered and reused, while only the consumable blades are discarded and replaced, extending the overall instrument life.
2Reliability
If blades are designed to be replaceable, then reliability is improved for each new use, but device complexity increases due to additional replacement mechanisms
Solution Approach 1:
The blade replacement mechanism is designed to be manually operated by the surgeon or assistant without requiring specialized tools or complex actuation systems. The surgeon can open the jaws, access the blades, and replace them using simple manual manipulation, making the system self-servicing in the operating room.
Solution Approach 2:
The blades are extracted as separate, easily removable components from the end effector assembly. The replacement mechanism extracts only the necessary blades for replacement while leaving the complex drive cables, pulleys, and housing intact, minimizing the complexity of the replacement process.
3Ease of operation
If blades are made easily replaceable, then ease of operation is improved, but time is lost during blade replacement procedures
Solution Approach 1:
The blades are pre-assembled with their securing features (such as set screws or bayonet mounts) already in position, allowing for quick installation. The end effector housing maintains permanent access openings that are prepared in advance, eliminating the need for complex disassembly during replacement.
Solution Approach 2:
The blade securing mechanism allows dynamic transition between locked and unlocked states. The surgeon can quickly release the blades by actuating a simple release mechanism or loosening a set screw, replace them, and secure the new blades without time-consuming operations.
Data Source
AI summary
A surgical tool includes a drive housing, a shaft extending from the drive housing, wrist arranged at an end of the shaft and including a distal clevis, an axle mounted to the distal clevis, and first and second actuation pulleys rotatably mounted to the axle and rotatable about a pivot axis extending through the axle, each actuation pulley providing an actuation boss eccentric to the pivot axis, and an end effector operatively coupled to the wrist and including first and second blades pivotably coupled to the actuation bosses of the actuation pulleys. The blades are movable between open and closed positions by rotating the actuation pulleys such that the actuation boss of each actuation pulley remains proximal to a centerline of the axle, and movable to an over-centered position by rotating the actuation pulleys such that the actuation boss of each actuation pulley is located distal to the centerline.