Abstract: A device for controlling an electric motor measures the current Im drawn by the motor and the torque Cm supplied by the motor. It includes a power supply 4 for the motor and an initialization unit 16 capable of generating a torque set point Cc and of receiving and processing information relating to the current Im and the torque Cm to deduce therefrom a relationship between the set point Cc, the torque Cm and the current Im in order to be able to determine the torque Cm from the set point Cc and the current Im.

Abstract: The invention relates to a screwing head, notably intended for installing caps on containers of bottle of similar type. This screwing head comprises an upper bush (8) fixed to the hub (1) and connected by elastic means to a lower bush (2) mounted to slide on the hub (1), these elastic means (5) being designed on the one hand to apply sufficient pressure to engage the bush (2) onto a friction disc (4) fixed to a bottom unit (3) provided with a screwing head and on the other hand to apply a preset torsional torque which, by working in conjunction with cam means, enables the bush (2) to be released from the friction disc (4) when the cap comes to the end of the tightening operation.