Abstract: A device for the measurement of distance with ultrasound is provided in which a transmitter emits a pulse-type signal which is reflected and is converted into an electrical echo signal in a receiver. The distance between transmitter and receiver is determined by measuring the transit time between the emitted and the received signal. Since the level of the echo signal as a function of the emitted signal depends on the characteristics of the reflector and on the distance between transmitter and receiver, inaccuracies may occur in the evaluation of the echo signal and these are avoided by varying a switching threshold or by varying the amplification of the echo signal or by modifying the radiated signal as a function of the previously received echo signal.

Abstract: A sensor circuit has a measuring circuit in which measuring signals occur at two different circuit points and signals at one point change oppositely to signals at the other point during changing of measuring values, and an evaluating circuit for evaluating measuring signals and outputting a sensor signal. The measuring circuit delivers the signals from the both points separately to the evaluating circuit. The evaluating circuit is formed so that it forms a difference of the both measuring signals and, for operational control of the sensor circuit, checks whether the measuring signals actually change oppositely to one another always within predetermined error limits.

Abstract: A pressure medium-tight inductive pickup for a fluid control element has a pressure pipe composed of a non-magnetic material, a magnetic core received in the pressure pipe, connecting means at the open end of the pressure pipe for pressure-tight connection of the pressure pipe with the control element, a spool body surrounding the pressure pipe, a housing surrounding the spool body and having an axis, and an adjusting element for adjusting zero position of the pickup, wherein the spool body is axially displaceable on the pressure pipe and in the housing, and the adjusting element is formed as a worm drive adjustable from outside and arranged so that the spool body is coupled with the worm drive in a play-free manner in an axial direction.

Abstract: An electrohydraulic control device for a lifting unit of an agricultural machine having a frame and a control rod pivotally secured to the frame by a fixed pivot pin, includes a transformer-type pick-up unit arranged in a well formed along the central axis of the pivot pin and cooperating with magnetically soft walls of the pivot pin to detect magnetic changes resulting from the load variations.

Abstract: The injection-molding machine is operative when activated for performing a complete injection-molding cycle. The machine includes a mold defining a mold cavity, a plastifying and injecting screw, and an hydraulic cylinder-and-piston unit for driving the screw. During the course of a single injection-molding cycle, negative-feedback control of the pressure in the mold cavity undergoes an automatic transition into negative-feedback control of the pressure in the hydraulic cylinder of the cylinder-and-piston unit. The transition is selected to be abrupt or gradual, and if gradual there will be a transitional interval during which a composite negative-feedback control of both the mold cavity and hydraulic cylinder pressures is occurring.

Abstract: An electro-fluidic signal converter has a body provided with an inlet and two outlets for pressure fluid. The body is composed of a pair of outer non-magnetic plates and a plurality of laminated-together inner magnetizable plates which are fluid-tightly sandwiched between the outer plates. The inner plates have respective plate portions which together constitute a body section that is resiliently deflectable out of a neutral position, and this body section is formed with a fluid channel which communicates with the inlet and has a discharge orifice that communicates equally with both of the outlets when the body section is in its neutral position. An electromagnet is located adjacent the body and is energizable to thereby deflect the body section out of its neutral position to one of a plurality of operated positions in which the discharge orifice communicates preferentially with one of the outlets. A method of making the body is also disclosed.