Abstract: A device for sucking up material removed by the bit of a portable drill is made in the form of a casing provided with means for securing it to the drill and having at least one portion constituting a handle to enable it to be gripped in one hand by the operator. The device comprises a suction head fitted slidingly on the casing to enable it to be kept close to the point of penetration into the surface of a body to be drilled by the bit fitted on the drill. Disposed inside the casing of the device are a fan with intake connected to said head through a connecting duct and with outlet blowing into a container, supported by the casing, for collecting the aspirated material, an electric motor to actuate the fan, electric batteries to supply power to the motor through an operating switch. The casing of the drill alternatively comprises an electric socket designed to receive a corresponding plug mounted on the vacuum device so as to supply power to the fan motor by taking it from the power supply of the drill.

Abstract: A control circuit for alternating current motors comprises a bidrectional controlled diode (TRIAC) connected in series to the motor and with its own control terminal connected to a fixed-phase actuating network in order to supply partial power to the motor. The control terminal is also connected to a switching device, piloted by a control signal to supply it, when closed, with a bias current which causes the continuous operation of the TRIAC, so as to supply full power to the motor. The control circuit can be used in conjunction with circuits which measure the current absorbed by the motor and give said control signal to make it switch from the full power condition to the partial power condition and vice versa whenever said current reaches pre-established thresholds. One of these circuits supplies partial power to the motor whenever the current it absorbs is too high, which indicates a mechanical overload.