Gear-Driven Medical Manipulator Brake Mechanism
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Solution Overview
Problem
In endoscopic surgical operations, medical manipulators with tiltable end effectors face challenges in maintaining the angle of the end effector due to reaction forces from biological tissues, leading to unintended movement, and existing brake mechanisms either provide insufficient braking force or require excessive operating force to release the braking action.
Innovation Solution
A brake mechanism featuring a brake rotor with a first gear on its circumference and a brake shoe with a second gear that meshes with the first gear, utilizing an elastic member to press the brake shoe against the rotor, providing a strong braking force while reducing the required elastic force and allowing easy release of the braking action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a worm gear is arranged in the power transmission path to prevent end effector movement due to reaction forces, then the end effector angle is maintained, but the operating member must be turned many times and responsiveness is deteriorated
Solution Approach 1:
The invention extracts the braking function from the power transmission path by placing the brake mechanism at the operating member side, separate from the worm gear. This allows the brake to prevent unwanted movement without interfering with the responsiveness of the power transmission mechanism during intentional operations.
Solution Approach 2:
The brake mechanism acts as an intermediary between the operating member and the mechanism to be controlled. It provides a braking force that prevents unwanted movement due to reaction forces, while allowing the power transmission mechanism to operate smoothly during intentional operations.
2Reliability
If the elastic force of the elastic member is increased to provide sufficient braking force, then the end effector angle is maintained, but the operating force needed to release the braking action becomes large
Solution Approach 1:
The brake mechanism is designed to be dynamically controllable, allowing the braking force to be adjusted by the operating force applied to the operating member. When the operating member is rotated, the brake shoe is separated from the brake rotor, reducing the braking force and allowing easy operation. When the operating member is stationary, the brake shoe presses against the brake rotor, providing maximum braking force to maintain the end effector angle.
Solution Approach 2:
The braking force parameter is changed dynamically based on the operational state. The brake mechanism transitions between a high braking force state (when the operating member is stationary) and a low braking force state (when the operating member is rotated), allowing both reliable angle maintenance and easy operation.
3Ease of operation
If the elastic force of the elastic member is decreased to reduce operating force, then the brake release becomes easier, but the braking force becomes insufficient and the end effector angle cannot be maintained
Solution Approach 1:
The brake mechanism uses dynamic control to provide different braking forces at different operational states. The elastic member provides a base braking force that is sufficient to maintain the end effector angle, while the dynamic separation of the brake shoe from the brake rotor during operation allows easy release without requiring excessive force.
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 brake mechanism achieves a sufficient braking force with reduced elastic force, enhancing operational ease by minimizing the force needed to release the braking action, thus stabilizing the end effector's angle during tissue interaction.
Implementation Method 1
the brake shoe is pressed against the brake rotor to thereby generate a braking force
Data Source
AI summary
A medical manipulator is provided with a brake mechanism. The brake mechanism is provided with a brake rotor and a brake shoe which can contact the outer periphery of the brake rotor. On the outer periphery of the brake rotor, a first gear is provided along the circumference. On the portion of the brake shoe which is opposite of the outer periphery of the brake rotor, a second gear is provided which can mesh with the first gear.