A robot which has three degrees of freedom along the X, Y and Z coordinate system. Usually consists of a spooling system (used as a crane), which when reeled or unreeled provides the up and down motion along the Z axis. The spool can slide from left to right along a shaft which provides movement along the Z axis. The spool and shaft can move forward and back along tracks which provide movement along the Y axis. Usually used to position its end effector over a desired object and pick it up.