Piston pump

A piston pump comprising:

• a. a casing defining an enclosed chamber of the pump together with closing means (2);
• b. a circular truncated pintle (3) with a conical periphery held by a slide block (4) slidably supported on said closing means (2) within said enclosed chamber, said slide block (4) having a trapezoidal cross-section with an inclined surface and end faces;
• c. two arcuate grooves (5, 6) located opposite each other on said conical periphery of said pintle (3), said arcuate grooves (5, 6) communicating with an inlet passage (9) and an outlet passage (10) formed on said closing means (2) through passageway opened in said pintle (3) and said slide block (4);
• d. a pressure space (12) provided on the inclined surface of said slide block (4) opposite said arcuate groove (6) communicating with said outlet passage (10), said pintle (3) and said slide block (4) are balanced by said pressure space (12);
• e. a cylinder block (30) having a plurality of cylindrical apertures arranged radially and vertically with respect to the conical periphery of said pintle (3), said cylinder block (30) being rotatably disposed over the conical periphery of said pintle (3);
• f. a a plurality of pistons (32a, 32g) with end faces, said pistons being disposed in each cylindrical aperture of said cylinder block (30);
• g. a cylindrical cup (36') with cup lips holder (34) having a plurality of flat faces (33a, 33g) in the interior wall thereof in contact with said outer end faces of said pistons (32a, 32g), said pistons being kept between said cylindrical holder (34) and said cylinder block (30);
• h. a driven shaft (36) coupled to said cup (36') for rotating said cylinder block (30) and said holder (34) together round the conical periphery of said pintle (3);
• and,
• i. means for sliding said slide block so that the axial center of said pintle (3) is eccentric from the axial center of said driven shaft (36).