Positioning device for positioning a movable element

A positioning device (1) for positioning a movable element (5), comprising:

• a base (B) comprising a flat guide surface (FF), which is arranged parallel to a first direction (X) and parallel to a second direction (Y);
• a first movement means (10) in Gantry design, which first movement means comprises a Gantry beam (15) arranged above the flat guide surface (FF) and extending in the second direction (Y) at a distance from the flat guide surface (FF), and a Gantry drive (GA) for moving the Gantry beam relative to the base (B) in the first direction (X), wherein the Gantry beam (15) has a first end (15.1) and a second end (15.2) located opposite the first end (15.1), and the Gantry drive (GA) comprises two first linear axes (X1, X2) extending in the first direction (X), each comprising a linear drive (LMX1, LMX2), wherein the linear drive (LMX1) of one of the two first linear axes (X1, X2) is connected to the first end (15.1) of the Gantry beam (15), and the linear drive (LMX2) of the other one of the two first linear axes (X1, X2) is connected to the second end (15.2) of the Gantry beam (15);
• a first air bearing means (LL1) comprising several air bearings connected to the Gantry beam (15) for guiding the Gantry beam on the flat guide surface (FF) of the base (B);
• wherein the movable element (5) is mounted on the Gantry beam (15) in such a way that the movable element (5) is linearly movable in the second direction (Y) on the Gantry beam (15), and the Gantry beam (15) has a second linear axis (Y1) extending in the second direction (Y) and comprising a linear drive (LMY) connected to the movable element (5) for moving the movable element (5) in the second direction (Y);
• wherein the first air bearing means (LL1) has a first air bearing arrangement (30), which comprises at least one first horizontal air bearing (31, 32) arranged on the first end (15.1) of the Gantry beam (15) for guiding the first end (15.1) of the Gantry beam (15) on a first section (FF1) of the flat guide surface (FF) extending in the first direction (X), which at least one first horizontal air bearing (31, 32) is preloaded with respect to the first section (FF1) of the flat guide surface (FF);
• wherein the first air bearing means (LL1) has a second air bearing arrangement (35), which comprises at least one second horizontal air bearing (36, 37) arranged on the second end (15.2) of the Gantry beam (15) for guiding the second end (15.2) of the Gantry beam on a second section (FF2) of the flat guide surface (FF) extending in the first direction (X), which at least one second horizontal air bearing (36, 37) is preloaded with respect to the second section (FF2) of the flat guide surface (FF);
• wherein the first air bearing means (LL1) has a third air bearing arrangement (50), which comprises at least one third horizontal air bearing (51, 52) and at least one fourth horizontal air bearing (53, 54), wherein the at least one third horizontal air bearing (51, 52) and the at least one fourth horizontal air bearing (53, 54) are arranged on a central section of the Gantry beam (15) between the first end (15.1) of the Gantry beam (15) and the second end (15.2) of the Gantry beam (15), so that the central section of the Gantry beam is guided on a third section (FF3) of the flat guide surface (FF) by means of the third horizontal air bearing (51, 52) and of the fourth horizontal air bearing (53, 54), which third section (FF3) of the flat guide surface (FF) extending in the first direction (X) and, with respect to the second direction (Y), being arranged between the first section (FF1) of the flat guide surface (FF) and the second section (FF2) of the flat guide surface (FF), wherein the at least one third horizontal air bearing (51, 52) and the at least one fourth horizontal air bearing (53, 54) have a distance relative to one another in the first direction (X), and the at least one third horizontal air bearing (51, 52) and the at least one fourth horizontal air bearing (53, 54) are preloaded with respect to the third section (FF3) of the flat guide surface (FF);
• wherein a guide beam (FB) extending in the first direction (X) is arranged on the base (B) next to the third section (FF3) of the flat guide surface (FF), the guide beam (FB) having a flat side surface (SF), which extends parallel to the first direction (X) and parallel to a third direction (Z), which third direction (Z) being directed essentially perpendicular to the flat guide surface (FF);
• and
• wherein the third air bearing arrangement (50) comprises at least one lateral air bearing (55, 56) arranged on the central section of the Gantry beam (15) for guiding the Gantry beam (15) on the one flat side surface (SF) of the guide beam (FB), wherein the at least one lateral air bearing (55, 56) is preloaded with respect to the one flat side surface (SF) of the guide beam (FB).