Abstract: A torque tool includes an electrical machine drive system, an electronic controller and a gear system. The drive system includes a rotor and a stator. The rotor includes a pattern of regions of relatively high magnetic permeability interspersed with regions of relatively low magnetic permeability extending generally parallel to the motor shaft such that there is a plurality of magnetic poles distributed circumferentially around the motor shaft. The stator includes electrical windings dispersed in slots disposed around an inner surface of the stator, the slots extending generally parallel to the motor shaft such that, when current flows in the windings, a stator magnetic field generated by the current has the same number of magnetic poles as the rotor. The electronic controller is configured to control the current flow in the stator windings to cause the stator poles to rotate in synchronism with rotation of the motor.

Abstract: There is described a torque tool comprising a synchronous reluctance motor. The torque tool comprises an electrical machine drive system, an electronic controller and a gear system. The drive system comprises a rotor and a stator arranged around the rotor. The rotor is attached to a motor shaft and comprises a pattern of regions of relatively high magnetic permeability interspersed with regions of relatively low magnetic permeability extending generally parallel to the motor shaft such that there is a plurality of magnetic poles distributed circumferentially around the motor shaft. The stator comprises electrical windings dispersed in slots disposed around an inner surface of the stator, the slots extending generally parallel to the motor shaft such that, when current flows in the windings, a stator magnetic field generated by the current has the same number of magnetic poles as the rotor.

Abstract: The invention relates to a reversible torque converter which is intended as a auxiliary device for use in connection with pneumatic, electric and/or hand-operated tools or machines, or which is intended to be incorporated in such machines and tools as an integrated part thereof. The switching or change-over means comprises a radially acting coupling which includes a dogging plate (4) mounted on the input shaft (2), a dogging cage (8, 9) mounted on the output shaft (3), and coupling elements (23) which are active between the two dogging elements and which are arranged for movement between an inner position, corresponding to direct drive, and an outer position, corresponding to a gearing-down drive, when the outward shaft (3) is driven via a planetary gear system (7; 31, 32, 33; 34) which acts upon the coupling elements (8, 9). The coupling elements (23) are spring-biased (10, 11, 12) with a force which must be exceeded in order for a change-over to take place.