Pneumatic spindle with means to direct the bearing air towards the tool-holding collet

Spindle (1), comprising:

• an outer case (1c) terminating at one end with a flange (7) having an aperture (6);
• a moving part (2) located co-axially within the outer case and extending through the aperture;
• a tool-holding collet (3) fixed to the moving part, the collet outwardly projecting from an end-most portion of the moving part;
• an air directing means (8) attached to an exterior surface of the flange at the aperture and surrounding the end-most portion of the moving part,
• an end-most portion of the collet extending outwardly beyond an end-most portion of the air directing means;
• an aerostatic bush generating a jet of compressed air that forms a cushion of air circulating continuously along air gaps (5) located between the moving part and the aerostatic bush and exits out of the case via a path defined by the air directing means at an outlet located intermediate the end-most portion of the air directing means and the end-most portion of the moving part,
• the moving part (2) supported by the cushion of air generated by a jet of compressed air, wherein,
• the air directing means (8) is shaped to collect the air exiting out of the outlet in a first direction and to redirect the exiting air from the first direction to a second direction with an outward direction of motion (E) tangential to the end-most part (3t) of the collet, the redirected exiting air moving roughly parallel to an axis of the spindle (1).