274 Industrial Robotics Fundamentals Copyright Goodheart-Willcox Co., Inc. Mechanical Finger Grippers Mechanical fi nger grippers fi are end effectors that are most commonly used for grasping objects. Mechanical fi nger grippers are generally used for grasping parts fi within a confi space, reaching into channels, or picking and placing any object fined that has a simple shape. The fi ngers typically move in a parallel or angular motion fi to grasp an object, Figure 9-4. The gripper fi ngers are opened and closed using fi mechanical linkages, gears, cables, chains, or pneumatic actuators. Grippers can have two, three, or four fi ngers. fi Two-Finger Grippers. Two-fi nger grippers have two stiff fingers fi that simu- fi late the motions of the human thumb and index fi nger, fi Figure 9-5. One or both of the fi ngers may move. For an additional degree of freedom and more flexibility fi fl during operations, a two-fi gripper may be equipped with a rotating joint, finger Figure 9-6. Gripper End Effectors Gripper Type Gripper Confi Gripper Movement Internal/External Gripping figuration Mechanical fi nger Two-finger fi fi Three-fi finger Four-fi finger Parallel or angular Internal and external Collet Round Square Hexagonal 360° clamping contact Internal and external Vacuum One or more suction cups Vacuum/suction External Electromechanical Permanent magnet Electromagnet Magnetic attraction External Goodheart-Willcox Publisher Figure 9-3. This classifi scheme can be used for mechanical grippers. fication Parallel Angular Goodheart-Willcox Publisher Figure 9-4. Two types of motion are made by mechanical grippers: parallel and angular.