Device for detecting the torque and the angle of rotation of a rotating shaft
A device for detecting torque features of an electric screwer comprises a clutch for coupling with the electric screwer and a clutch for applying a resisting torque. The two clutches ( 11, 13 ) are connected to one another by a shaft ( 14 ) on which there are arranged extensometers ( 15 ) for measuring the torque transmitted by the shaft. On the shaft there is splined a disc ( 18 ) that bears on at least one face circular tracks ( 19, 20, 21, 22 ) that are coaxial to the shaft and to which the extensometers are electrically connected. Sliding contacts ( 23, 24, 25, 26 ) rest elastically on said circular tracks in a direction that is substantially parallel to the axis of the shaft to pick up the electric signals from the extensometers. An encoder ( 17 ) is provided to detect shaft rotation.
1. Device for detecting torque features of an electric screwer comprising a clutch for coupling with the electric screwer and a clutch for applying a resisting torque, the two clutches ( 11 , 13 ) being mutually connected by a shaft ( 14 ) on which there are arranged extensometers ( 15 ) for measuring the torque transmitted by the shaft, a rotating contact assembly ( 16 ) providing an electrical connection to the extensometers that rotate with the shaft and an encoder being connected to the shaft to detect the angular rotation thereof, characterized in that the encoder comprises an electronic sensor ( 33 ) with a Hall effect that detects the angular position of a facing magnet ( 34 ) rotated by the shaft wherein the magnet ( 34 ) is fixed axially on a pulley ( 35 ) connected by a belt ( 36 ) to a pulley ( 37 ) splined on the shaft ( 14 ).
2. Device according to claim 1 , characterized in that said contact assembly ( 16 ) comprises at least a disc ( 18 ) that is splined on the shaft and that bears on at least one face thereof circular tracks ( 19 , 20 , 21 , 22 ) that are coaxial to the shaft and to which the extensometers are electrically connected, and sliding contacts ( 23 , 24 , 25 , 26 ) that rest elastically on said circular tracks in a direction that is substantially parallel to the axis of the shaft.
3. Device according to claim 2 , characterized in that the disc ( 18 ) has circular tracks ( 19 , 20 , 21 , 22 ) on both faces thereof.
4. Device according to claim 3 , characterized in that the tracks ( 19 , 20 , 21 , 22 ) are two on each face of the disc.
5. Device according to claim 2 , characterized in that the disc ( 18 ) is formed by several assembled layers, the innermost layer being a printed-circuit base ( 28 ) connecting conductors of the extensometers and the circular tracks ( 19 , 20 , 21 , 22 ).
6. Device according to claim 5 , characterized in that the circular tracks ( 19 , 20 , 21 , 22 ) are formed by rings fixed on the two faces of the base ( 28 ) that forms the innermost layer.
7. Device according to claim 2 , characterized in that the contact surface of the circular tracks ( 19 , 20 , 21 , 22 ) is made of graphite.
8. Device according to claim 2 , characterized in that the sliding contacts ( 23 , 24 , 25 , 26 ) comprise two elastic arms suitably directed along the respective circular track, each arm terminating with a contact zone ( 32 ) on the track.
9. Device according to claim 8 , characterized in that the contact zones ( 32 ) have a graphite contact surface.