Abstract: A work machine having a diesel engine driving a plurality of ground movement devices to tow an agricultural implement. A torque estimating system is employed to determine the level of torque in the drive train between the diesel engine and the ground movement devices. The torque estimation device is a sensor determining the axial and radial deflection of an input shaft as a function of the torque transmitted between a pair of adjacent gears in the power train.

Abstract: A work machine having a diesel engine driving a plurality of ground movement devices to tow an agricultural implement. A torque estimating system is employed to determine the level of torque in the drive train between the diesel engine and the ground movement devices. The torque estimation device is a sensor determining the axial and radial deflection of an input shaft as a function of the torque transmitted between a pair of adjacent gears in the power train.

Abstract: The control circuit comprises a source of dc voltage, a first electronic switch, interposed between a first terminal of the voltage source and a corresponding first terminal of the load, a second electronic switch, interposed between the other or second terminal of the load and the other or second terminal of the source, a current recirculation device, including a diode connected between the said first terminal of the load and the other or second terminal of the voltage source to allow a circulation current in the load when the first switch is open, and a control circuit arranged to control the switches in a predetermined manner. The recirculation device further includes a third electronic switch disposed between the first terminal of the load and the other or second terminal of the voltage source, and the control unit is arranged to control this third switch in a synchronous manner, but in phase opposition, in relation to the first switch.

Abstract: A control circuit that drives an electronic actuator. The control circuit includes a direct voltage source, a chopper circuit arranged between the source and an electric actuator, and an electronic control circuit designed to apply to the chopper circuit a command signal of the PWM type, with a predefined ON/OFF switching period and a predetermined duty cycle, for a predefined activation time, to produce a flow, within the electric actuator, of a correspondingly switched current having a nominal duration corresponding to the activation time. The control circuit detects the last whole or complete switching period included within the activation time, splits, in accordance with a predefined duty cycle, the final interval including the last complete switching period and any subsequent fraction of a switching period included within the activation time, and drives the chopper circuit in this final interval.

Abstract: The system makes it possible to control at least one piezoelectric actuator having a capacitive impedance and includes a source of voltage, a control circuit branch in parallel with the source, in which the actuator is connected in series to two electronic switches each having a respective parallel diode; an energy accumulating inductor with one terminal connected between the said switches and the other connected to the voltage source; and an electronic unit operable to control the said controlled switches according to predetermined modes of operation.

Abstract: The control circuit comprises: a direct voltage source; a chopper circuit arranged between the source and an electric actuator; and an electronic control circuit designed to apply to the chopper circuit a command signal of the PWM type, with a predefined ON/OFF switching period and a predetermined duty cycle, for a likewise predefined activation time, so as to produce a flow, within the electric actuator, of a correspondingly choppered current having a nominal duration corresponding to the activation time. The unit being arranged to: detect the last whole or complete switching period included within the activation time; allocate in accordance with a predefined duty cycle the final interval comprising said last complete switching period and any subsequent fraction of a switching period included within said activation time, and correspondingly drive the chopper circuit in this final interval.

Abstract: The control circuit comprises a source of dc voltage, a first electronic switch, interposed between a first terminal of the voltage source and a corresponding first terminal of the load, a second electronic switch, interposed between the other or second terminal of the load and the other or second terminal of the source, a current recirculation device, including a diode connected between the said first terminal of the load and the other or second terminal of the voltage source to allow a circulation current in the load when the first switch is open, and a control circuit arranged to control the switches in a predetermined manner. The recirculation device further includes a third electronic switch disposed between the first terminal of the load and the other or second terminal of the voltage source, and the control unit is arranged to control this third switch in a synchronous manner, but in phase opposition, in relation to the first switch.

Abstract: The system makes it possible to control at least one piezoelectric actuator having a capacitive impedance and includes

Abstract: An electromagnetic actuator, particularly for a valve for controlling the injection of fuel or fuel oil is described and comprises: a fixed permanent magnetic core, and an electrical control winding which is disposed in the magnetic field generated by the core and is movable relative to the core when an electrical current flows through the winding, in which the winding is intended to be connected to a movable member actuable by the device, in a manner such as to bring about movement of the movable member between a rest position and at least one operative position. The winding is also arranged to act on the movable member by exerting a resilient force which can hold the member in the rest position or return the member to the rest position.

Abstract: An actuator for a control valve includes a piezoelectric actuating member for bringing about the movement of a closure member of the valve between an open position and a closure position; the member has a reference portion for connection to a fixed portion of the device and a free portion for connection to the closure member, the free portion being movable relative to the reference portion as a result of mechanical deformations produced in the actuating member by the piezoelectric effect. The reference portion of the actuating member is controllable selectively between a condition in which it is locked in a reference position and is fixed firmly to the fixed portion of the device, and a free condition in which it is movable relative to the fixed portion.

Abstract: An electromagnetic actuator, particularly for a valve for controlling the injection of fuel or fuel oil is described and comprises:

Abstract: An actuator device for a control valve is described and comprises a piezoelectric actuating member for bringing about the movement of a closure member of the valve between an open position and a closure position; the member has a reference portion for connection to a fixed portion of the device and a free portion for connection to the closure member, the free portion being movable relative to the reference portion as a result of mechanical deformations produced in the actuating member by the piezoelectric effect.

Abstract: A control circuit for supplying a load with current having a high-amplitude ortion with a rapid leading edge, and a lower-amplitude portion. The circuit is input-connected to a low-voltage supply source, and comprises a number of actuator circuits parallel-connected between the input terminals and each including a capacitor and a load. Each actuator circuit also comprises a first controlled switch between the respective load and a reference line, for enabling energy supply and storage by the respective load. A second controlled switch is provided between the capacitor line and the load line, for rapidly discharging the capacitors into the load selected by the first switch and recirculating the load current, or for charging the capacitors with the recirculated load current.