Step by step motor

Claim 1

A SYNCHRONOUS MOTOR COMPRISING, A STATOR HAVING AN ANNULAR FIELD WINDING, A PERMANENT COAXIAL MAGNET MAGNETIZED IN AXIAL DIRECTION AND TWO MAGNETIC HALF CIRCUITS COUPLED WITH THE MAGNET AND THE ANNULAR FIELD WINDING, A ROTOR ROTATABLE IN SAID STATOR COMPRISING A PERMANENT ANNULAR MAGNET, SAID ROTOR HAVING A HUB OF INSULATING MATERIAL FLANGED RADIALLY TO OVERLIE ONE SIDE OF SAID ANNULAR MAGNET, AND AN ARMATURE SHAFT EXTENDING THROUGH SAID HUB AND HAVING RETAINING MEANS FOR LOCKING SAID HUB AND SAID SHAFT IN COROTATION INCLUDING AN INSULATING DISK CARRIED ON SAID SHAFT AND EXTENDING RADIALLY OUTWARDLY OF SAID HUB TO OVERLIE A PORTION OF THE OPPOSITE SIDE OF SAID ANNULAR MAGNET, SAID ANNULAR MAGNET HAVING AN EVEN NUMBER OF NORTH AND SOUTH POLES IN ALTERNATE POSITIONS AROUND THE PERIPHERY THEREOF, SAID TWO MAGNETIC HALF CIRCUITS COMPRISING TWO END PLATES AND LONGITUDINAL POLE PIECES EQUAL IN NUMBER TO SAID ROTOR POLES, SAID POLE PIECES EACH CONSISTING OF A POLE PLATE SUBSTANTIALLY PERPENDICULAR TO A RADIUS OF THE ROTOR, AND POLE PLATES FROM ONE END PLATE ALTERNATING WITH POLE PLATES FROM THE OTHER END PLATE OF THE OTHER END PLATE OF THE MAGNETIC CIRCUIT, SAID POLE PIECES HAVING THE SAME SHAPE AND BEING ASYMMETRICAL IN THE DIRECTION OF THE PERIPHERY OF THE ROTOR, THE ASYMMETRY BEING IN THE SAME DIRECTION IN EACH POLE PIECE.