Rotating Coupling for Robotic Tool Changer
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Solution Overview
Problem
Existing robotic tool changers face challenges in providing a compact, secure, and reliable mechanism for coupling and decoupling tools, especially in surgical applications where mechanical parts are covered and positive locking against inadvertent opening is critical, and existing piston-actuated ball member arrangements can lead to wear and require axial motion, limiting design flexibility and safety.
Innovation Solution
A manual robotic tool changer with a rotating coupling mechanism using a one-way clutch and dual-button handle locking mechanism, which allows for compact design, secure coupling, and prevents inadvertent decoupling, featuring a rotating cam surface ring that actuates ball members without axial piston motion and includes safety features like a failsafe surface and spring bias for automatic partial engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a piston-actuated ball member arrangement is used to lock the master and tool units together, then the coupling can be secured with a simple mechanism, but the piston requires axial motion space and the ball members are subject to wear from repeated actuation
Solution Approach 1:
Instead of using a piston that moves axially to actuate the ball members, the invention inverts the approach by using a rotating cam surface ring that rotates to actuate the ball members. The cam surfaces are positioned radially around the central axis, converting axial coupling motion into radial ball member actuation through rotation rather than linear translation.
Solution Approach 2:
The invention replaces the piston-cylinder mechanical actuation system with a rotating cam mechanism. The cam surface ring with inclined cam surfaces substitutes for the piston, using rotational motion and geometric surfaces to achieve the same ball member actuation function without requiring axial piston travel.
2Ease of operation
If a single button latch mechanism is used on the handle, then the device is easier to operate, but it is more susceptible to inadvertent decoupling
Solution Approach 1:
The dual button latch mechanism implements preliminary anti-action by requiring simultaneous depression of two buttons to release the latch. This creates a preliminary barrier against inadvertent operation, as accidental single-button pressure (from drops, bumps, or unintended contact) cannot trigger decoupling. The system proactively prevents errors before they can cause failure.
3Adaptability or versatility
If the ball members are allowed to rotate freely in both directions, then the coupling mechanism has greater flexibility, but it cannot prevent inadvertent decoupling
Solution Approach 1:
The invention segments the rotation path by introducing a cam surface ring with distinct cam surfaces positioned at specific angular locations. The first cam surface enables controlled rotation in one direction (coupling or tightening), while the second cam surface restricts rotation in the opposite direction (preventing decoupling). This segmentation of the rotational degree of freedom provides both flexibility and protection.
Solution Approach 2:
The cam surface ring creates dynamic, direction-dependent behavior: it permits rotation in the coupling direction while restricting rotation in the decoupling direction. The mechanism adapts its constraints based on the direction of applied force, allowing flexibility during intended operation while providing automatic protection against unintended decoupling.
4Volume of moving object
If a compact rotating coupling mechanism is used instead of axial piston motion, then the device size is reduced and design flexibility increases, but the mechanism becomes more complex
Solution Approach 1:
The rotating cam surface ring serves multiple functions simultaneously: it actuates the ball members to engage the coupling, it provides the locking action through the second cam surface, and it enables the handle's rotational motion to be converted into radial ball member actuation. This multi-functionality consolidates several mechanisms into one component, achieving compactness without excessive complexity.
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 provides a compact, lightweight, and secure tool changer that prevents inadvertent decoupling, reduces wear, and ensures safety by requiring simultaneous actuation of both latch buttons for unlocking and using a one-way clutch to restrict decoupling, enhancing safety and usability in surgical environments.
Implementation Method 1
A one-way clutch mechanism is operative to allow rotation of the cam surface ring in the coupling direction and to restrict rotation of the cam surface ring in the decoupling direction unless by actuation of the handle
Implementation Method 2
a spring biasing the tool changer to an at least partially coupled state when no force is applied to the handle
Data Source
AI summary
A manual robotic tool changer provides a compact, lightweight means to manually selectively couple a robotic tool, such as a surgical tool, to a robot arm. The tool changer includes numerous safety features to prevent inadvertent decoupling of the robotic tool. These include a dual-button handle locking mechanism operative to lock the tool changer closed in the fully coupled position, and requiring simultaneous actuation of both of two latch buttons to unlock; a one-way clutch mechanism that prevents rotation of the coupling mechanism towards the decoupled position, unless the handle is actuated to unlock the tool changer; and a spring biasing the tool changer to an at least partially coupled state when no force is applied to the handle, thus requiring a positive force against the spring, moving the handle to a fully open position, to insert or remove a robotic tool.