Robotic welder for nuclear boiling water reactors

Abstract

One aspect of the present invention comprises an apparatus for storing an end effector nestably adjacent a pipe to which it is attached and for moving the end effector into a working position laterally-displaced from said pipe is disclosed. Such apparatus desirably is part of the robotic welding apparatus wherein the end effector is a welding head. This apparatus comprises a pair of pipe segments in rotating end-abuttable relationship, each segment bearing a ring gear about its circumference; a pair of helical lotus petals having an in inner surface which conforms to the outer surface of the pipe segment to which each lotus petal is hingedly attached at its distal end, each lotus petal being attached hingedly at their respective distal ends to a lotus petal hinge attachment stage; drive means drivably connected to each of said ring gears for separately driving each pipe segment; and an end effector carried by said lotus petal hinge attachment stage. Each lotus petal and said lotus petal hinge attachment stage, and thus said end effector, are nestably stored adjacent their respective pipe segments. The end effector is movable to a working position laterally-displaced from said pipe by said drive means driving said pipe segments in opposite directions. The end effector is movable horizontally (Y axis motion) by driving said pipe segments differentially in the same direction.