Abstract: A shield support for underground mining has a slider and a roof bar between which a ram is arranged, with an inclination detector being provided with which the inclination of the roof bar can be measured.

Abstract: The present invention relates to a valve. The valve includes a valve element having a metering opening, a valve gate which is movable in translation for the opening and closing of the metering opening, an actuating actuator configured for the execution of a tilting movement, and a lever arm which is coupled to the actuating actuator and which converts the tilting movement of the actuating actuator for the opening and closing of the metering opening into a translatory stroke movement of the valve gate.

Abstract: A method is proposed for measuring thickness and detecting double and missing sheets during the sheet feed to a sheet-processing machine, such as a sheet-fed printing machine. A corresponding monitoring apparatus has one or more sensing elements above or beneath the sheet stream. The sensing element can be displaced, with an actuating device having an actuating drive, in the direction towards and away from the sheet stream. The actuating drive has at least one piezoelectric actuator or it is formed by the latter.

Abstract: Design by a consumer of a lighting plan for illuminating a space is facilitated. An electronic display is provided of a room showing a plurality of areas thereof. Selection by the consumer of any one from among the plurality of areas is enabled, and then selection by the consumer of any one from among a plurality of lighting arrangements available for illuminating the selected area is enabled. The consumer is enabled to repeat the area selection and lighting arrangement selection for all of the plurality of areas. The room is displayed as illuminated by the combined effect of illuminating all of the plurality of areas with the lighting arrangements respectively selected therefor, so that the overall effect of the combination of lighting arrangements in all the areas of the room is simulated as realistically as possible. The consumer can thus find the best overall lighting plan.

Abstract: A method is proposed for measuring thickness and detecting double and missing sheets during the sheet feed to a sheet-processing machine, such as a sheet-fed printing machine. A corresponding monitoring apparatus has one or more sensing elements above or beneath the sheet stream. The sensing element can be displaced, with an actuating device having an actuating drive, in the direction towards and away from the sheet stream. The actuating drive has at least one piezoelectric actuator or it is formed by the latter.

Abstract: The present invention relates to a piezo-electric torque actuator with low stress electrodes. The present invention is specially used to produce tilting motions in high frequency ranges. The invention provides for forming a piezo-electric stack element with required external electrical connection contacts with a substantially reduced mechanical load and which direct tilting motions without required additional means for motion transformation. The present invention is formed of at least two areas of piezo-electric stacks, and an area arranged there between which contains segments that are affect only partially or are unaffect by an electrical field generated by the flat laminate contacts. This is accomplished by disposing external electrode connections of the two areas as far as possible in the direction of field-reduced or field-free areas, wherein the in between area is connected with the two areas (1 and 2) at least in positive fit.

Abstract: The invention relates to a tilting device that makes it possible to tilt around at least one axis, with a tilting member, a base member, and an elongated holding device arranged beneath the tilting member. At least two stabilizing members, of rectangular shape, are installed, offset from each other, on the base member. Connecting members between the holding device and the stabilizing members engage the holding device at different heights. During movement of at least one stabilizing member, at least another stabilizing member remains rigidly fixed at one location.

Abstract: A highly dynamic piezo-electric drive mechanism for use wherever stringent requirements are placed on resonant frequency, positioning time, actuation speed or acceleration, is provided and in which at least two piezo-electric double stack drives are rigidly mounted on their first base surfaces and act against a toggle lever on their second base surface on opposite sides of and equidistant from the pivot axis of the toggle lever, and a control applies a phased electrical voltage to the piezo-electric stacks in such manner that the double stack drives operate in a push-pull mode.

Abstract: A piezoelectrically actuated driving and adjusting apparatus transmits both pure translation movements and rotation movements. The object of the present invention is to provide a piezoelectrically actuated driving and adjusting apparatus having a simple, compact and robust mechanical structure, capable of ensuring long adjustment paths and suitable for various adjustment and drive tasks using the same principle structure. Two parallel stacks of piezoelectric elements are arranged as close as possible to each other. The piezoelectric stacks are supported at first front surfaces on a crossbar by a tiltable coupling. Second front surfaces of the piezoelectric stacks, opposite to the first front surfaces, lie flat on a stiff common member that rigidly interconnects both the piezoelectric stacks. A biasing apparatus is provided to apply a symmetrical, predefinable force on the piezoelectric stacks by acting on the crossbar and the common member.

Abstract: The invention relates to a piezoelectric transducer particularly for use in transit time measurements. The object of the invention is to provide a piezoelectric transducer which ensures an in-phase two-dimensional pulse emission which, independent of the selection of a definite excitation frequency, substantially closely follows the electric excitation at a low time deformation of the pulse owing to transient and dying-out operations and which permits to obtain sufficiently high sound levels at low amplitudes of the excitation voltage.

Abstract: The present invention comprises an applicator head for the dosed dispensation of fluid mediums wherein a valve member and a valve drive are arranged within a casing. The valve drive comprises at least one piezoelectric element connected with a voltage supply and comprising several parallel, juxtaposed piezoelectric stacks which are flexibly mounted. The present invention provides a piezoelectrically driven applicator head which is simple and economical to manufacture, and which is usable not only in the low-temperature range but also in the high-temperature range.

Abstract: In an apparatus for operating a valve element consisting of a base, an operating lever pivotally journalled with respect to the base and a drive apparatus which is secured to the base and engages the operating lever which has at least one of its ends for operating on the valve element, the drive apparatus comprises two piezo-electric transistors which are secured with a nonparallel orientation between the base and the operating lever such that they are each moveable relative to the base and the operating lever about an axis parallel to the pivoting or rocking axis of the operating lever.

Abstract: An electro-hydraulic control system for a mineral mining installation has a plurality of control units (4) sub-divided into operational groups (I, II, III) with associated roof supports. Each group has its own power source (5) and power at an intrinsically safe level is provided to each of the groups independently of and in isolation from the other groups. The control units (4) are interconnected via a system data bus (13,14) in the form of conductors of multi-core cables which also carry the electrical power. A further data bus (20) independent of the system bus (13,14) is coupled to some of the units of the groups.

Abstract: An electro-hydraulic control system has a valve unit allocated to a roof support (support shield, support trestle or the like) and equipped with electromagnetic valves. The unit is controlled by a control unit via a cable which includes two current supply leads serving as a common current supply for all the electromagnetic valves and at least one data bus through which an actuator connected with the valve unit is actuated from a microprocessor of the control unit. The actuator itself consists preferably of a shift register through which all the electromagnetic valves can be actuated.

Abstract: A power supply arrangement which is intended, in particular, for intrinsically safe electro-hydraulic control systems for mining and comparable applications, in which several control units and loads controlled thereby are supplied as a group from a common constant voltage source. The voltage source has a current capacity which is smaller than the total current requirement of all the units and loads supplied by it. Each control unit has actual value current measuring device and two controllable current sources which are connected to a common potential line which can simultanously act as a data bus. The arrangement enables the respective effective dynamic current consumption and demands of the control units and loads to be ascertained to enable the available power of the constant voltage source to be determined at any time at the individual control units.

Abstract: The operation of an electromagnetic valve is monitored by connecting the coil of the valve to a d.c. source for a period of time sufficient to permit the current in the coil to reach its maximum steady state value then disconnecting the coil to permit the current to fall and re-connecting the coil to the source again and measuring the current which is established in the coil.

Abstract: A system serves to establish the spatial position of an object automatically. The system uses a computer-controlled lasar beam scanning technique to locate the three-dimensional positions of mirror devices in successive measuring stations spaced from the object.

Abstract: A system serves to establish the spatial positions of a cutter head of a tunnel driving machine with precision and monitors and/or controls this position automatically. The system uses a computer-controlled laser beam scanning technique to locate the three-dimensional positions of mirror devices in successive measuring stations spaced along the tunnel.

Abstract: In the method and installation for determining a relative distance between the front wall (22) of the cylinder and the piston (14), an ultrasonic converter (30) is used to which a plate (68) presenting a reflecting reference surface (66) for the formation of a reference path is secured. The group of reference oscillations (R) and the group of measurement oscillations (M) appearing in the output signal of the converter (30) after the emission of a group of transmitter oscillations (S) are detected by means of threshold switches (108, 120, 122). Thereby, a measurement signal and a reference signal are obtained, the latter being used for compensation by means of a processor (38) for the influence of the different propagation conditions affecting the measurement signal.

Abstract: Production of tertiary (hydroxymethyl)-methylphosphine oxides of the general formula: ##STR1## in which R stands for a branched or unbranched, substituted or unsubstituted alkyl, cycloalkyl, aralkyl or aryl group having from 1 to 18 carbon atoms. To this end tertiary bis-(hydroxymethyl)-phosphines of the general formula ##STR2## in which R has the meaning given above, are subjected to a thermal rearrangement reaction at temperatures higher than about 90.degree. C or at temperatures within the range -10.degree. and +250.degree. C, in the presence of a catalyst.