Abstract: There is disclosed a radial piston machine comprising a cylinder block having at least one bore in which a piston supported on an eccentric disk is movably guided via roll bodies, wherein at least one hydrostatic relieving field is provided between the piston and the roll body. According to the invention, the active surface A2 of the relieving field is equal to or larger than the active piston area A1 of the piston restricting a cylinder chamber and the relieving field is in fluid communication with the cylinder chamber via a hydraulic resistance.

Abstract: An actuating drive for a rotor blade in a wind power installation is provided with an electric motor and a frequency converter which has a rectifier that is to be fed from a power supply system, a link connected to the rectifier, and a d.c.-to-a.c. inverter for feeding the motor, the link carrying a specified nominal operating voltage in a network-fed normal operation of the frequency converter. Furthermore, an auxiliary energy supply device is provided that is connected to the link. The auxiliary energy supply device includes and energy store which makes available a support voltage that amounts to less than 80% of the nominal operating voltage of the link. A diode is connected between the energy store and the link, and is arranged, with regard to its forward direction, in such a way that it feeds a support voltage from the energy store into the link if the link voltage falls below the support voltage.

Abstract: An on-off valve is disclosed, especially a fast-acting on-off valve, wherein a plunger is pretensioned in a base position. The plunger has a plurality of parallel control edges via which a plurality of sectional opening cross-sections, arranged in parallel in a hydraulic manner, can be jointly actuated to open or close when the valve is switched.

Abstract: An on-off valve is disclosed, especially a fast-acting on-off valve, wherein a plunger is pretensioned in a base position. The plunger has a plurality of parallel control edges via which a plurality of sectional opening cross-sections, arranged in parallel in a hydraulic manner, can be jointly actuated to open or close when the valve is switched.

Abstract: An actuating drive for a rotor blade in a wind power installation is provided with an electric motor and a frequency converter which has a rectifier that is to be fed from a power supply system, a link connected to the rectifier, and a d.c.-to-a.c. inverter for feeding the motor, the link carrying a specified nominal operating voltage in a network-fed normal operation of the frequency converter. Furthermore, an auxiliary energy supply device is provided that is connected to the link. The auxiliary energy supply device includes and energy store which makes available a support voltage that amounts to less than 80% of the nominal operating voltage of the link. A diode is connected between the energy store and the link, and is arranged, with regard to its forward direction, in such a way that it feeds a support voltage from the energy store into the link if the link voltage falls below the support voltage.

Abstract: A drive mechanism for an injection molding machine has an output element that is moveable in a straight line and an electric motor drive unit having an electric motor and a piston-cylinder unit which has a first piston-cylinder unit in the force chain between the output element of the electric-motor drive unit and the movable component. A rapid actuating movement is possible and, the action of a high force is also achievable wherein a second piston-cylinder unit and a third piston-cylinder unit. A fluidic connection between the first cylinder chamber and the second cylinder chamber is controllable via a valve. When the valve is open, the second hydraulic piston displaces pressurized liquid from the second cylinder chamber into the first cylinder chamber, to actuate the movable component and, when the valve is closed, the third hydraulic piston displaces pressurized liquid from the third cylinder chamber into the first cylinder chamber to exert a high force on the movable component.

Abstract: An injection unit for a plastic injection molding machine having a screw, having a motion spindle as first drive element, via which the screw can be rotationally driven for the plasticization and is movable in the axial direction for the injection, having a spindle nut as second drive element, which is coupled to the motion spindle via a motion screw thread, having a large electric motor which is arranged so as to be fixed to the frame and by which, while one drive element is held against rotation, the other drive element can be rotationally driven for moving the screw during the injection, and having a device which is arranged so as to be fixed to the frame and by which a rotational speed of the one drive element can be preset during the plasticization, this rotational speed being different from the rotational speed at which the large electric motor simultaneously drives the other drive element.

Abstract: A drive device has a drive element movable axially by means of an electric motor and a hydraulic unit. In the drive device it is important to execute a rapid adjusting movement and then to exert high forces. This causes high reaction forces on the lifting spindle. High reaction forces are avoided if a force intensifier with two pistons movable in relation to one another and differing from one another in the size of their active surfaces along with an intermediate part which, together with the pistons, encloses a pressure space filled with a pressure fluid is used, if the smaller active surface is connected mechanically to the drive element, for the adjusting movement, the hydraulic unit can be moved as a whole, and if, for exerting a high force by means of the larger active surface, the intermediate part can be blocked against displacement in relation to a fixed stand.

Abstract: A drive device for closing unit, injection unit or ejectors of a plastics injection molding machine, has a drive element which is axially moveable, and a hydraulic unit which is moveable by the drive element in the same direction as the drive element. The hydraulic unit is a force multiplier with a large piston and a first small piston, which are moveable in relation to one another and differ in size of their effective surface areas. An intermediate part together with the pistons encloses a pressure chamber filled with a pressure fluid. The first small piston is mechanically connected to the drive element. A second small piston with the intermediate part define a fluid chamber connected by a valve, in one embodiment, to the pressure chamber. The hydraulic unit as a whole is moveable for the positioning movement and the intermediate part is blockable against displacement in relation to a fixed frame.

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 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: An electromechanical clamping device with hydraulic assistance. A thrust mechanism driven by an electric motor displaces two clamping jaws with respect to each other along a guide device. One clamping jaw is divided into two mutually displaceable part java. A chamber to hold pressure medium is formed between the part jaws. The first part jaw can be displaced along the guide device and locked with respect to the latter. One part jaw is provided with a first cylinder coupled to the output of the thrust mechanism. In order to close the clamping device, in a first step the thrust mechanism pulls the part jaws against the other clamping jaw, and in a second step the thrust mechanism delivers pressure medium from the first cylinder into the chamber between the two part jaws, with the first part jaw locked with respect to the guide device.

Abstract: The invention relates to a drive device, which is used in particular for the closing unit, the injection unit or the ejectors of a plastics injection molding machine and which has a drive element which can be axially moved by an electric motor and a hydraulic unit which, by moving the drive element, can be moved in the same direction as the latter. Drive devices for the stated applications depend on firstly performing a rapid positioning movement and then exerting great forces. In the case of a known drive device with the stated features, the hydraulic unit is a hydraulic cylinder, which is displaced during the positioning movement by the electric motor via a lifting spindle and to which pressure medium is supplied via a valve for the exertion of a great force. In the case of this known drive device, apart from the electrical installation, a complete hydraulic system is also necessary. Furthermore, great forces of reaction act on the lifting spindle.

Abstract: A drive for a movable part, such as a mold closure platen, includes two hydraulic cylinder-and-piston units defining first and third pressure chambers in a first of the hydraulic units and defining fourth and fifth pressure chambers in a second of the hydraulic units, and wherein the piston of one of the hydraulic units is a stepped piston defining a second pressure chamber, thereby providing five pressure chambers. An arrangement of valves provides for selective coupling of hydraulic fluid among the pressure chambers whereby pressure medium is forced from one of the hydraulic units, during an advance of its piton, to the other of the hydraulic units.

Abstract: The invention proceeds from a drive device which is used, in particular, for the closing unit, the injection unit or the ejectors of a plastic injection molding machine and which has a drive element movable axially by means of an electric motor and a hydraulic unit movable as a result of the movement of the drive element in the same direction as the latter. In drive devices for the applications mentioned, it is important first to execute a rapid adjusting movement and then to exert high forces. In a known drive device having the features mentioned, the hydraulic unit is a hydraulic cylinder which, during the adjusting movement, is adjusted by the electric motor via a lifting spindle and to which pressure medium is supplied via a valve for the purpose of exerting a high force. In this known drive device, high reaction forces act on the lifting spindle.

Abstract: In an arrangement comprising a motor/pump unit and a sound-deadening cover, the sound-deadening cover absorbs the airborne noise emitted by the motor/pump unit. On the other hand, the sound-deadening cover acts like the diaphragm of a loudspeaker for the structureborne noise emanating from the motor/pump unit. In order to absorb the structureborne noise as well, the sound-deadening cover is constructed as a sound-deadening hood, and is placed over the motor/pump unit in the operating condition, without touching it. During transportation, the sound-deadening hood and the motor/pump unit are supported on one another. The arrangement is used to absorb sound from units comprising a pump and a motor driving the latter.

Abstract: What is disclosed is a clamping unit for an electrically operable injection molding machine having a drivable spindle whereby a mold backing plate may be moved in the closing direction. On the spindle a nut is guided, the axial movement of which may be transmitted to a mold backing plate. The axial or rotational movement of the nut acts on tilting members capable of being taken into clamping positions wherein the clamping forces acting on the mold backing plate may directly be introduced into the spindle or into a frame of the injection molding machine via the tilting members so as to alleviate the load on the spindle drive.

Abstract: An electromechanical clamping device with hydraulic assistance is described. A thrust mechanism driven by an electric motor displaces two clamping jaws with respect to each other along a guide device. One clamping jaw is divided into two mutually displaceable part jaws. A chamber to hold pressure medium is formed between the part jaws. The first part jaw can be displaced along the guide device and locked with respect to the latter. One part jaw is provided with a first cylinder coupled to the output of the thrust mechanism. In order to close the clamping device, in a first step the thrust mechanism pulls the part jaws against the other clamping jaw, in a second step the thrust mechanism delivers pressure medium from the first cylinder into the chamber between the two part jaws, with the first part jaw locked with respect to the guide device.

Abstract: The force of an electric motor, whose rotational movement is translated into a longitudinal movement by a transmission, and the force of the piston of a hydraulic cylinder act in the longitudinal direction on an axially displaceable machine part. The force exerted by the electric motor is limited to a value at which no damage occurs to the transmission. In order to limit the force component applied by the electric motor, the desired value for the force acting on the machine part in the axial direction and the actual value of this force are used to form a control difference, which controls the sum of the force components acting on the machine part in the axial direction. The actual value of the force acting on the machine part in the axial direction and a value that takes into account the mechanical load-bearing ability of the transmission are used to form a desired value for the force acting on the piston in the axial direction.

Abstract: The invention relates to a drive device, which is used in particular for the locking unit, the injection unit, or the ejector of an injection-moulding machine for plastics and which has a drive element that can be axially displaced by an electromotor and a hydraulic unit that can be displaced in the same direction as the drive element by being entrained by the latter. The hydraulic unit is a power-transmission element comprising two pistons which can be displaced in relation to one another and have working surfaces of different dimensions.