Cam-Locked Tool Changer for Higher Stiffness and Moment Capacity
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Solution Overview
Problem
Current robotic tool changers face issues with reduced moment carrying capability and stiffness due to centrally located locking mechanisms, leading to potential tool dropping during programming errors and requiring custom adapter plates, which increase cost and weight, and lack the ability to function both manually and automatically.
Innovation Solution
A tool changer design where the master and tool halves are locked and unlocked via deliberate robot motion, using a securing mechanism with a clasp and cam system that provides accurate positioning and resistance to lateral and torsional forces, and can be manually unlocked, eliminating the need for pneumatic cylinders and custom adapters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pneumatic cylinder is used to lock the tool in the center of the tool changer, then the locking mechanism is compact and simple, but the tool changer height increases and moment carrying capability decreases
Solution Approach 1:
The locking mechanism is relocated from a vertical arrangement (pneumatic cylinder in master half) to a horizontal arrangement (cam-actuated arms in tool half), changing the spatial dimension of the locking action. This allows the locking points to be positioned at the extreme ends of the tool changer, maximizing the moment arm without increasing device height.
2Device complexity
If locking balls with point contact are used, then the locking mechanism is simple, but the contact area is small and stiffness is reduced
Solution Approach 1:
The invention replaces point-contact spherical locking balls with cam-actuated arms that provide line or surface contact. The cam mechanism transforms the locking action from a single-point engagement to a distributed contact along the cam arm, significantly increasing the contact area and stiffness while maintaining mechanical simplicity.
3Adaptability or versatility
If a custom adapter plate is used to mount the tool changer to the robot, then mounting flexibility is improved, but cost, weight, and height increase
Solution Approach 1:
The tool half is designed with an integrated mounting interface that directly interfaces with standard robot flanges. The cam-actuated locking arms and mounting features are built into the tool half structure itself, eliminating the need for separate custom adapter plates while maintaining mounting flexibility across different robot platforms.
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
This design enhances the stiffness and moment carrying capability of the tool changer, reduces the risk of tool dropping due to programming errors, and allows for both manual and automatic operation, improving the reliability and versatility of the tool changer system.
Implementation Method 1
The securing mechanism includes a clasp and a cam. The clasp moves between a release position and a grasping position. In the grasping position, the master and tool halves are secured together with one another. The cam moves the clasp between the release and grasping positions.
Data Source
AI summary
A tool changer 30 with a master half 32 and tool half 34. Mating member 60, 138 enables the master half 32 and tool half to mesh with one another. A securing mechanism has a clasp 70 and a cam 72. The clasps 70 move between a release position and a grasping position. In the grasping position, the master 32 and tool halves 34 are secured together with one another. The cam 72 moves the clasps 70 between the release and grasping positions. From a release position, the master half 32 engages the tool half 34. The master half 32 moves horizontally with respect to the tool half 34. This, in turn, moves the cam 72 from its release position to its grasping position. In the grasping position, the clasps 70 grasp the tool half 34, the cam locks 72 in its grasping position and the master 32 and tool 34 halves secure with one another.