Abstract: A method for register correction in machines for processing webs of material includes providing at least one transport shaft and at least one processing shaft cooperating with the at least one transport shaft, driving the shafts synchronously with one another each by an individual drive mechanism, obeying by at least one shaft a chronological guide shaft function which corresponds to an instantaneous position of a guide shaft, correcting a plurality of register-tracking shafts formed by the transport shafts in accordance with a scan of register marks or the web of material relative to the guide shaft function, effecting only one common scanning for one group of the register-tracking shafts which correspond to one another in term of the register correction, and deriving from the only one common scanning a common correction function that all of the register-tracking shafts of the group obey.

Abstract: When using solenoid coils in an explosion-hazard environment, in order that no sparks are produced in the event of a discontinuity in an electrical line leading to the solenoid coil, two or more identical zener diodes are connected in parallel with one another and to the solenoid coil. In order to verify the operability of all the zener diodes which are connected in parallel with one another and to the solenoid coil, the electrical values of the zener diodes and of the solenoid coil are measured before assembly. The total capacitance of the circuit arrangement is measured after assembly. The capacitance of the solenoid coil is subtracted from the total capacitance, and the remaining value is divided by the number of parallel-connected zener diodes. The result is compared with the capacitance of a single zener diode, with the magnitude of the difference between these values being used as a criterion for the operability of the zener diodes.

Abstract: There is disclosed a hydraulic control arrangement for damping driving vibrations of a mobile machine, comprising a lifting cylinder supporting a working tool whose cylinder chambers can be connected to a fluid source or a tank via a control valve arrangement. The hydraulic control arrangement has a damping valve arrangement including a control valve in which a check valve is integrated through which a bottom-side chamber of the lifting cylinder is connectable to a hydraulic accumulator. In the pressure control function the accumulator can be connected to a tank so that the accumulator pressure is restricted to a maximum value.

Abstract: In a pressure switch, which emits an electrical switching signal as a function of the magnitude of a pressure which is supplied to it, which electrical switching signal assumes a first value when the pressure is less than the threshold value and which assumes a second value when the value is greater than the threshold value, the threshold value is adjusted—assuming that this is provided at all—by hand, for example by moving a cam disk which is coupled to a rotary knob. In order to adjust the threshold value by an electrical signal, the pressure is supplied to a pressure sensor, which emits an electrical output signal, which is a measure of the pressure which is supplied to the pressure sensor. The pressure switch is supplied with an electrical input signal which is a measure of the threshold value.

Abstract: A drive device which is used in particular for the closing unit, the injection unit or the ejectors of an injection molding machine for plastics and which has a drive element which can be moved axially by an electric motor, and a hydraulic unit which can be moved in the same direction as the drive element by moving the latter. In drive devices for the applications, it is important to first of all perform a rapid regulating movement and then exert high forces. In a known drive device having these features, the hydraulic unit is a hydraulic cylinder which is adjusted by the electric motor via a stroke spindle during the regulating movement and to which pressure medium is fed via a valve for exerting a high force. In this known drive device, in addition to the electrical installation, a complete hydraulic system is also necessary. In addition, high reaction forces act on the stroke spindle.

Abstract: A free-piston engine has a stepped piston having a larger end face thereof guided in the compression cylinder, and a smaller end face in the work cylinder. Both the work cylinder and the compression cylinder are connected with a common high-pressure accumulator for initiating the compression stroke or for charging during the expansion stroke.

Abstract: What is disclosed is a pilot apparatus whereby at least two mechanically operable control valves and two electrically or electro-hydraulically operable control valves may be driven. The pilot apparatus comprises a pivoted lever having two handles, on each of which a switching element for driving the electrically/electro-hydraulically operable control valves is provided.

Abstract: A brake system for a mobile work tool, such as for a logging machine or a combined dredger-loader, is disclosed. The mobile work tool is provided with two non-muscular brake valves for brake actuation which may be operated by the driver in accordance with the orientation in the driver's cab—for instance during road travel and when the driver's direction of view is to the rear. In accordance with the invention, a tank port of a non-muscular brake valve is connected with the brake port of the second non-muscular brake valve, so that the first non-muscular brake valve is connected via the tank port of the second non-muscular brake valve with the pressure medium tank, and upon actuation of the second non-muscular brake valve the generated braking pressure is supplied via the tank port of the first non-muscular brake valve into the latter, so that the brake ports thereof are correspondingly subjected to braking pressure.

Abstract: A hydraulic transformer includes a multiplicity of displacers each guided in a displacer chamber. Pressure medium supply and discharge to and from the displacer chambers is controlled through the intermediary of control means provided with control recesses. The effective position of the control recesses in relation to the dead center positions of the displacers is variable, with each displacer volume being adapted to be connected with a dead space in a commutation phase upon transition between two adjacent control recesses.

Abstract: What is disclosed is a hydraulic steering apparatus with steering amount amplification, wherein a metering device for supplying pressure medium to steering cylinders is actuated in accordance with an amount of rotation of the steering wheel. With the aid of a control block it is possible to deliver an additional pressure medium volume to the steering cylinders, wherein control of the control block in accordance with the invention is effected through the intermediary of a control circuit containing an effective control pressure that is substantially lower than the load pressure for transmitting the steering moment at the steering cylinder. There is moreover disclosed a spring assembly for the control block, wherein two springs are arranged in parallel, one of which only takes effect following a predetermined stroke of the control element.

Abstract: A device for detecting a relative movement between two machine parts movable relative to one another has a plurality of marking rulers arranged on one of the machine parts one after the other in direction of the relative movement of the machine parts and having increment markings for detecting a distance of a relative movement of the both machine parts, two sensors for sensing of the marking rulers and arranged on the other of the machine parts at the predetermined distance in the direction of relative movement of the machine parts, the sensors sensing the increment markings and each providing a sensing signal; the marking rulers being arranged so that distances between two neighboring ones of the marking rulers being smaller than the predetermined distance between the sensors, an evaluating unit operative for determining an absolute position of the corresponding sensor between two successive increment markings based on a phase position of the sensing signal of the sensors.

Abstract: The invention is based on a pressure-medium cylinder having a piston which has a piston rod, and having a measuring system for determining the absolute position of the piston rod relative to a reference point. Firstly, the measuring system has a code track of binary code elements which is applied to the piston rod and runs along the piston rod, which code elements are formed by grooves and plateaus which run in the circumferential direction in a magnetically conductive base material, which is coated with a protective layer, of the piston rod, and, secondly, the measuring system has a sensor which is in a fixed position relative to the reference point and has two or more sensor elements, which are arranged along the code track and each scan a limited number of code elements.

Abstract: Disclosed is a directional control valve comprising a front-side connector and at least one radial connector, wherein the front faces of a valve body (valve shift or seat body) of the directional control valve are pressurized approximately equally, so that the actuating forces for shifting the valve body are minimal. In accordance with the invention, the pressure for pressurizing a rearward front face of the valve body is tapped at an axial distance to the valve body.

Abstract: In a method for operating machines (138) with a plurality of shafts (102, 110, 111), in which the shafts (102, 110, 111) are each driven, synchronized with one another, by individual drive mechanisms (103) belonging to them, in accordance with an electronic, chronological guide shaft function, which corresponds to an instantaneous position of a guide shaft L, and the motions of a plurality of derived shafts (102, 110, 111) are derived from the guide shaft L in accordance with conversion functions that correspond to respective predetermined mechanical conversions (106, 107, 108, 109) with respect to the guide shaft L, it is proposed, in order to improve the method in such a way that—particularly when there is a large number of shafts to be regulated—simple startup at comparatively little expense for equipment is permitted, that all the shafts (102) of at least one group (117) of shafts, which correspond to one another in terms of the conversion (106, 107, 108, 109), obey an electronic, chronological following

Abstract: A drive device which is intended for displacing two linearly movable components of a plastics injection-molding machine at least partly at successive times, in particular for displacing the injection unit for bringing the injection nozzle into contact with a mold and for displacing the injection mechanism for injecting polymer into the mold. With a known drive device, arranged downstream of an electric rotating motor are two clutches, by which rotational movements are transmitted on the basis of frictional engagement, and with which wear accordingly occurs. Each clutch is followed by a threaded drive, by which the rotational movement of the output element of a clutch is transformed into the linear movement of the machine component to be displaced.

Abstract: There is disclosed a stop block for controlling a hydraulic consumer in which a main piston having an advanced opening can be lifted off a valve seat in a return function by means of a push piston. A pressure chamber confined by the main piston on the one hand and by the control piston on the other hand is connected to a tank or low-pressure passage both in the return function and in the non-return function of the stop block so that the change-over from the return function to the non-return function and vice versa can be effected very quickly.

Abstract: A hydrostatic drive (1) with a hydraulic pump (3) and a plurality of hydraulic motors (6-9) that are hydraulically linked with the hydraulic pump (3). One speed sensor (20; 21; 22; 23) each allocated to a respective hydraulic motor (6; 7; 8; 9) and is linked with a control device (24) and detects the speed (n1; n2; n3; n4) of the allocated hydraulic motor (6; 7; 8; 9). Every hydraulic motor (6; 7; 8; 9) is functionally linked with a brake device (26; 27; 28; 29) that in turn is linked with the control device (24). When the speed (n1; n2; n3; n4) of one of the hydraulic motors (6; 7; 8; 9) exceeds a predetermined threshold value (ng), the control device (24) triggers the brake device (26; 27; 28; 29) allocated to the associated hydraulic motor (6; 7; 8; 9).

Abstract: A valve assembly for load pressure-independent control of consumers is disclosed, which includes a main valve having a directional element and a metering throttle part. The valve assembly includes a shut-off valve for leakage-free shutting off of a work line leading to the consumer. This shut-off valve is designed with a pilot valve whereby a pressure chamber of the shut-off valve acting in the closing direction may be relieved towards a tank or a low-pressure source. The pilot valve is, in accordance with the invention, controlled open by a main slide of the main valve.

Abstract: A device for controlling a hydraulic actuator includes an electrically operated valve that controls the flow of a pressure medium in the actuator in response to the operations of three controllers. A first of the controllers designates a position of a piston of the valve. A second of the controllers commands movement of the actuator. And a third of the controllers electronically controls a sequence of movements of the actuator. The three actuators are arranged in a common housing located on the valve.

Abstract: A method for offshore load transfer and a floater for use in such load transfer are described. A hydraulic device for use in a horizontal positioning system for keeping the floater in position is also described. During the mounting and dismantling of large structures offshore, the floater will be exposed to wave and wind forces. By means of hydraulic jacks the floater is kept in a target position, within a horizontal frame. The jacks act as a positioning system and may also act as a sea fastening or sea securing system for the load when it is carried by the floater.