A gripper apparatus for removing and replacing objects such as containers or vials in an array of containers has a gripper head which extends downward from a support arm, a planetary gear assembly mounted in the gripper head including at least three planet gears, and at least one gripping pin extending downward from each planet gear and projecting beyond a lower end of the gripper head. A drive motor drives the planetary gear assembly to rotate the planet gears in opposite directions, moving the pins inward and outward along predetermined paths to grip and carry an object and release the object when in a desired location.