GB762668A - Improvements relating to electrical measuring instruments - Google Patents

Abstract

762,668. Electric torque-measuring systems. DAIMLER-BENZ AKT.-GES. Aug. 18, 1953, No. 22753/53. Class 40 (1). Apparatus for measuring the torque transmitted by a shaft by noting the change in inductance of a coil fixed to one part of the shaft having a movable core attached to another part of the shaft, is characterized in that the coil and its core are curved to follow the angular twist more accurately. The coil and its core may alternatively be the two electrodes of a variable condenser.. The coil (or condenser) preferably comprises two separate parts forming a differential inductance (or capacitor) located in adjacent arms of a measuring bridge. In one embodiment (Figs. 11, 12) a shaft 10 has a central bore 11 carrying a rod 12 rigidly clamped to the shaft at one end 13 and free to rotate relative to the shaft in a bearing 15 at the other end, which end also carries a curved core 17, 17<SP>1</SP> movable in correspondingly curved coils 18, 18<SP>1</SP> rigidly secured to the shaft 10. In another embodiment (Fig. 13) the torque transmitted by a torsion.bar 22 connecting two shafts 20a, 20b is determined by the relative movement of two-part curved coils 24 attached to the free end of a sleeve 23 rigidly attached to the right-hand end of the torsion bar and a correspondingly curved two-part core 26 rigidly attached to the other end of the bar 22 by a clamp 25. In each embodiment connections are made to the various coils by slip rings 40, 41, 42, and a further slip ring 43 may be added to obtain an impulse per revolution for a revolution counter. Provision may be made for raising the contact brushes from the slip rings when not required, to avoid unnecessary wear.