Robotic Tool Changer Coupling Mechanism with Increased Torsional Stiffness

A method of coupling master and tool assemblies of a robotic tool changer, comprising:

• moving a plurality of rolling members disposed in bores in the master assembly towards a plurality of scalloped cutouts formed in a bearing race of the tool assembly, each scalloped cutout including a valley and opposed sloped surfaces;
• seating the plurality of the rolling members on opposed sloped surfaces of the cutouts by misaligning the rolling members with the cutouts and contacting the sloped surfaces with the rolling members such that the rolling members are offset with respect to the valley of the cutouts;
• and
• wherein some of the rolling members contact one sloped surface of some cutouts and other rolling members contact the opposite sloped surface of other cutouts thereby generating counterforces that prevent or minimize relative rotation between the master and tool assemblies.

A robotic tool changer comprising:

• a tool assembly including:
• a bearing race;
• a plurality of target cutouts formed in the bearing race, the target cutouts being circumferentially spaced around the bearing race with each target cutout including a valley and opposed sloped surfaces;
• a master assembly including:
• an annular collar;
• an array of bores formed in the collar, each bore configured to contain a rolling member;
• a drive mechanism configured to force the rolling members into the contacts to couple the master and tool assemblies, and to allow the rolling members to retract to decouple the master and tool assemblies;
• the array of bores including a first pair of generally aligned bores formed in the collar and including a first pair of rolling members, and a second pair of generally aligned bores formed in the annular collar and including a second pair of rolling members;
• wherein when the master and tool assemblies are coupled:
• the first and second pairs of bores and the rolling members therein are misaligned with respect to target cutouts;
• the respective rolling members are offset with respect to the valleys in the target cutouts and contact sloped surfaces of the target cutouts;
• wherein the rolling members of the first pair of bores contact sloped surfaces of two of the target cutouts that are opposite of the sloped surfaces contacted by the rolling members of the second pair of bores;
• and
• wherein torsional stiffness of the tool changer is enhanced since the respective points of contact between the rolling members and the sloped surfaces prevent or minimize the tool assembly from rotating relative to the master assembly.