Abstract: A transducing head includes at least three magnetic layers. At least two of these magnetic layers function as shields of a reader portion of the transducing head, and at least one of these magnetic layers functions as a pole of a writer portion of the transducing head. Importantly, at least one of the three magnetic layers is formed of a thin film structure having a first and a second ferromagnetic layer, a nonmagnetic spacer layer, and a bias layer. The spacer layer is positioned between the first and the second ferromagnetic layers. The bias layer is positioned adjacent the first ferromagnetic layer. The second ferromagnetic layer has a thickness-magnetic moment product substantially equal to a thickness-magnetic moment product of the first ferromagnetic layer. An easy axis of the second ferromagnetic layer is substantially parallel to an easy axis of the first ferromagnetic layer.

Abstract: A transducing head includes at least three magnetic layers. At least two of these magnetic layers function as shields of a reader portion of the transducing head, and at least one of these magnetic layers functions as a pole of a writer portion of the transducing head. Importantly, at least one of the three magnetic layers is formed of a thin film structure having a first and a second ferromagnetic layer, a nonmagnetic spacer layer, and a bias layer. The spacer layer is positioned between the first and the second ferromagnetic layers. The bias layer is positioned adjacent the first ferromagnetic layer. The second ferromagnetic layer has a thickness-magnetic moment product substantially equal to a thickness-magnetic moment product of the first ferromagnetic layer. An easy axis of the second ferromagnetic layer is substantially parallel to an easy axis of the first ferromagnetic layer.

Abstract: The invention relates to a control device for stopping the operation of a single-phase asynchronous motor with a capacitor in the event an overload of this motor with respect to a threshold value is detected. This device is characterized in that it includes, on the one hand, device for measuring the phase shift between any one parameter, voltage or current (U1, U2, I2, I3) of the main phase (.phi.1) or the secondary phase (.phi.2) and another one of these parameters and, on the other hand, device for controlling the stoppage capable of interrupting the current supply to the motor in the event there is measured a time delay lower than a memorized threshold value.

Abstract: A driving and tensioning device for a flexible protective member such as a strip, curtain or skirt includes a rolling-up driving-shaft and an unrolling driving-shaft which are driven by electric motors provided with a brake activated in order not to brake any longer when one of these motors is under power. This driving and tensioning device furthermore includes a device for controlling the power supply to the motors so that a torque is generated by one of the motors withstanding the operation of the other motor, during the phase of either unrolling or rolling-up of the flexible protective member.

Abstract: The invention relates to a motor-driven roller blind comprising, on the one hand, an apron rolling up onto and unrolling from a winding shaft inside which is accommodated a tubular-type driving gear-motor and, on the other hand, means providing an electrical signal representative of the movement of the apron and an electrical-signal processing unit capable of acting on the running of the driving gear-motor, viz. to control the stopping of same in the event an obstacle is present. As a matter of fact, said means providing an electrical signal representative of the movement of the apron are comprised of at least one inductive sensor extending at least partly along the path followed by the apron, this inductive sensor being capable of creating an electromotive force under the action of the passing of a permanent magnet associated with the lower portion of the apron, which electromotive force is detected by the processing unit.

Abstract: The invention relates to a device for controlling the variation of the power and/or the speed of a load (2), such as an asynchronous, synchronous, universal motor, a transformer, an inductance, a condenser or a resistor, comprising a switch (5) placed on a phase (4) of a single-phase or multiphase alternating-current supply-circuit (3), this switch (5) being associated with means (6) for controlling the cyclic ratio .alpha./T in which .alpha. corresponds to the time of opening and closing of the circuit (3) by the switch (5) and T to the period of the phase (4) on which this latter is placed. In fact, the switch (5) is of the bidirectional MOS, IGBT or bipolar transistor switch type, this switch (5) being associated with means (9) for controlling the switching time, of the DRIVER type, capable of extending the switching time at closing so that it be within a range from 10 microseconds to 1 millisecond.

Abstract: The object of the process is to obtain an intermediate short-circuiting ring in a squirrel cage rotor by filling. It makes use of the technique consisting in automatically cutting out and assembling rotor laminations by means of a follow-on machine in which the laminations are cut out from a strip, rotated through a determined angle and provided with half-cutouts for their assembly in a packet. The process consists in eliminating at least one tooth in every two from the laminations whose position in the packet corresponds to the situation of the intermediate short-circuiting ring, and turning these laminations through an angle such that when filling is effected a continuous annular zone of nonmagnetic material is obtained.

Abstract: The present invention relates to an asynchronous motor having a squirrel-cage rotor, associated with a brake operating in the absence of current. The rotor comprises, at its two opposite ends, first and second short-circuiting rings and an intermediate short-circuiting ring, all three being made from non-magnetic material and being connected by longitudinal rotor windings. The intermediate ring extends radially from the outer diameter of the rotor as far as a cylindrical recess provided axially between the second ring and the intermediate ring. It is provided in order to separate a part of the rotor, intended to deflect the corresponding part of the radial stator field towards the moveable plate of the brake. This moveable plate has a radial face arranged opposite segments of magnetic material arranged radially between the periphery of the second ring and the outer diameter of the rotor. The second ring extends radially as far as the recess.

Abstract: This invention relates to a device for driving a flexible protection element rolled up on a winding shaft, the free end of the element being connected through one or a plurality of flexible bonds to a winding drum. The winding drums and the winding shaft are coupled through reversible reduction gears to corresponding electric motors and to a pair of electromagnetic brakes of the type operating by current deficiency. The first motor is adapted to rotate in a first direction for rolling up the flexible bonds. The second motor is adapted to rotate in a direction opposite to that of the first motor for rolling up the flexible protection element. Electrical or electronic means are provided for actuating anyone of the two motors and simultaneously energizing the two brakes. This invention is applicable notably for driving protection tents, canvasses and the like in glasshouses, greenhouses and the like.