Abstract: A press for compressing pulverulent materials into both concave and convex pieces includes a press frame, a die carying plate, upper and lower punches, holders for carrying the punches and control devices for controlling the displacement of the upper and lower punches. The press comprises also a first piston-cylinder device for controlling the displacement of the die carrying plate, a second piston-cylinder device fastened to the frame and supporting the die carrying plate, levers arranged above the die carrying plate and having one end pivoted to the frame and sliders slidable on the opposite ends are provided in the press. The first piston cylinder device acts on the other ends of the levers to exert thereon a pressure depending on the distance of the sliders from the other ends of the levers.

Abstract: A sintered self lubricating bearing comprising at least an area of the inner surface, with a permeability value reduced in respect to that of the remaining mass, the number of reduced permeability areas varying from one to two times the numerical value of the diameter expressed in millimeters.