Abstract: There is provided a magnetic head used for both magnetic recording and reproduction thereof, comprising a magnetic head body with a gap portion, wherein a first material having a larger saturated magnetic flux density than that of said body is applied to one or both sides of said gap portion, said gap being internally provided with a second material having a smaller saturated magnetic flux density than said body.

Abstract: This invention discloses an electric motor comprising a stator, a rotor disposed concentrically within the stator, a drive shaft rotatably supporting the rotor with a circular gap between the stator and rotor and an output shaft connected to the drive shaft and sharing the same rotating axis with the drive shaft, wherein the improvement is characterized in that the electric motor further includes a resilient connecting member which connects the drive shaft and the output shaft and means which detects the torsion of the resilient connecting member produced during the transmission of the torque from the rotor to the output shaft and measures the transmission torque from the detected torsion.

Abstract: Torsion sensor for a grinding machine having a torsion bar with non-linear characteristics provided between the drive shaft of the grinding machine motor and the grinding wheel spindle, and detector means for detecting the twisting angle of the torsion bar.