Low-Profile Tool Changer With Cam Clasp Locking for Higher Stiffness
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Solution Overview
Problem
Existing robotic tool changers are tall, reducing the moment carrying capability of robots, and lack stiffness due to center-located locking mechanisms, leading to tool deflection and potential tool damage from programming errors. Additionally, they often require custom adapter plates and fail-safe designs that do not protect against programming errors.
Innovation Solution
A tool changer design featuring a master half coupled with a robot and a tool half coupled with a tool, using a securing mechanism with a clasp and cam plate system that can be manually or automatically actuated, and includes a vacuum or compression connection to enhance stiffness and prevent tool deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a center lock with expanding ball connection is used, then the locking mechanism is compact and can be located near the center, but the tool changer becomes tall which reduces the moment carrying capability of the robot
Solution Approach 1:
The locking mechanism transitions from a vertical arrangement (expanding balls moving axially) to a radial arrangement (wedges moving horizontally outward). This dimensional change allows the locking action to occur in the radial direction rather than requiring vertical space, thereby reducing the overall height of the tool changer while maintaining effective locking capability.
2Device complexity
If the locking mechanism is located at the center, then the device structure is simplified, but the moment arm between opposing members is shortened which reduces the capability to resist moment loading
Solution Approach 1:
The locking mechanism uses asymmetric wedge shapes that convert horizontal movement into radial expansion forces. The wedges are positioned and oriented to create long moment arms that extend outward from the center, allowing the locking mechanism to resist moment loading effectively despite being compact at the center location.
3Device complexity
If point contact between master and tool halves is used, then the locking mechanism is simple, but concentrated stresses cause brinelling of the balls and mating couplers
Solution Approach 1:
The locking interface uses curved wedge surfaces instead of point contacts. The wedge-shaped locking members have rounded contact surfaces that distribute stress over larger areas, preventing concentrated stresses that would cause brinelling. The curved surfaces maintain smooth rolling contact while increasing the effective contact area.
4Adaptability or versatility
If a custom adapter plate is used to mount the tool changer to the robot, then mounting flexibility is improved, but costs, weights and height are increased
Solution Approach 1:
The tool changer is designed with a universal mounting interface that can accommodate multiple robot types without requiring custom adapter plates. The mounting flange incorporates standardized bolt patterns and positioning features that work with various robot end effectors, providing mounting flexibility while eliminating the need for additional adapter components.
Data Source
AI summary
A tool changer 30 with a master half 32 and tool half 34. 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 laterally with respect to the tool half 34. This, in turn, moves the cam 72, and thus the clasps, from their release positions to their grasping positions. 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.