high-force linear motor assembly using tandem axes.

A linear motor assembly having enhanced mechanical stiffness, comprising: (a) at least one pair of rigidly interconnected tandem rails (14,15) defining a first axis of movement and spaced apart normal to such first axis; (b) at least one pair of frames (20,21) movable along said pair of rails (14,15), each frame presenting at least one pair of opposed parallel bearing surfaces; (c) at least one linear motor (26) effective to operate between each rail and frame; (d) bearings (60) supported between each rail and each bearing surface of each frame, said bearings being preloaded with an interference load while permitting bearing movement; and (e) support structure (27,28) between said frames defining axes of movement actuated by other linear motors.