Torque indicating means for rotary members

997,723. Measuring torque electrically. LICENTIA PATENT-VERWALTUNGS-G.m.b.H Aug. 9, 1962, No. 30580/62. Heading G1N. A torque measuring apparatus comprises an electromagnetic transmitter fitted to and rotating with rotary driving and driven members 10, 12 and which includes an oscillator the frequency of which is torque dependent, and a stationary electromagnetic receiver which is frequency sensitive. A hollow shaft 10 coupled to a motor, the torque/ speed relationship of which is to be evaluated, is capable of restricted angular movement relatively to a housing 13 terminating in a coupling 21 itself connected to a mechanical brake. A torque rod 11, which may be replaceable to suit different motors, is joined at one end to the shaft 10 and at its other to a ring member 12 itself connected to the coupling 21 by grub screws. The driving torque of the motor causes the rod 11 to twist and axially displace a core 17 relatively to a coil 19. The core 17 extends normally to, but is displaced from, the axis of rod 11 and is mounted on the shaft 10 by brackets 16, the coil 19 being secured to the housing 13. The frequency of an oscillator comprising transistor 18 and powered by batteries 23 is controlled by the inductance of the coil 19 and hence produces a signal which is torque dependent, and is radiated from an antenna 20. The receiver, which may be of the superheterodyne type, converts the variable frequency signal to D.C. and energizes a recording device which may include a second channel on to which the voltage output from a unipolar tacho-generator, driven from the motor under test, is also recorded.