Abstract: Disclosed is a drive unit, in particular for a closing unit, an injection unit, or an ejector of an injection molding machine. The drive unit comprises a double-acting force transmitting element provided with a small and a large piston unit which are disposed in a cylinder. The large piston unit is adapted to be pressurized by a great force both in input and in output directions. According to the invention, both the large piston unit with respect to the cylinder and the cylinder with respect to a movable element of the drive of the small piston unit are spring-prestressed.

Abstract: What is disclosed is a drive mechanism, in particular for blanking and nibbling machines, comprising a hydraulic force transmitting element and a spindle drive for driving the force transmitting element, wherein a pre-tensioning means for pre-tensioning the force transmitting element is provided.

Abstract: What is disclosed is an injection unit for an injection molding machine, comprising a screw which may be driven by means of a spindle drive. Driving of the spindle drive is effected by means of an electric motor. In addition, through the intermediary of a hydraulic cylinder a force acting in the axial direction is transmitted to the screw of the injection unit. In accordance with the invention, the electric motor drives a pump whereby a pressure chamber of the cylinder may be supplied with more pressure medium than is required in an axial displacement of the cylinder.

Abstract: What is disclosed is a drive unit, in particular for a closing unit, an injection unit, or an ejector of an injection molding machine, wherein a high axial force may be applied through a hydraulic power converter. A cylinder of the power converter may be fixed relative to a frame of the injection molding machine through the intermediary of a holding means which is functionally separate from guidance of the cylinder on the frame of the injection molding machine.

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: What is disclosed is an axial-piston machine having at least one swash plate and one cylinder drum supported thereon, which includes a multiplicity of cylinder sleeves. To the cylinder sleeves a row of pistons is associated which is connected with a shaft. In accordance with the invention, the cylinder sleeves are articulatedly mounted in the cylinder drum.

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: What is disclosed is a hydraulic unit for a plastics processing machine, in particular a hydraulically actuated injection molding machine. In accordance with the invention, the drive mechanism of a pump of a hydraulic circuit is provided inside the tank to ensure optimum acoustic and vibration attenuation.

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: A free-piston engine directed to reduced throttling losses at minimum expenditure is provided. The free-piston engine has an engine piston, and a hydraulic piston co-operating with the engine piston. The engine piston may receive application of a force in the direction of compression via a hydraulic cylinder. A pressure in a high-pressure accumulator means or a low-pressure accumulator may be communicated to the hydraulic cylinder via a switchover valve. Between the hydraulic cylinder and the switchover valve is a valve assembly including a control piston. A connection to the high-pressure accumulator means may be controlled open with the aid of the control land of the control piston.

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: 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 hydraulic unit for a plastics processing machine, in particular a hydraulically actuated injection molding machine. In accordance with the invention, the drive mechanism of a pump of a hydraulic circuit is provided inside the tank to ensure optimum acoustic and vibration attenuation.

Abstract: A hydrostatic drive system for an injection molding machine which has a movable mold-closing plate comprises a hydraulic pump and a differential hydraulic cylinder, by which the mold-closing plate can be moved in the direction of the closing position by the feeding of pressure medium into the second pressure space remote from the piston rod and can be moved in the direction of the open position by the feeding of pressure medium into the first pressure space on the piston-rod side.

Abstract: A releasable check valve for use with very high system pressures. The check valve is formed such that the poppet piston is relatively smooth-running and that good action and a long service life of the seals are obtained, wherein the receiving bore has essentially the same diameter in the region of the inserts and between the inserts. A spacer bushing is arranged axially between the inserts, in which bushing the piston collar can move separating the two annular spaces on both sides of it fluidically from each other. The bore can be machined from one side, so that the inserts are centered precisely with respect to one another and the poppet piston is guided precisely. This reduces the risk of jamming and the risk of an uneven load on the seals.

Abstract: The supply of pressure medium to hydraulic or pneumatic cylinders is usually carried out by means of pressure medium lines which are connected to the heads of the cylinders by means of standardized connection threads. This method of supplying pressure medium requires a minimum wall thickness of the casing of the cylinder in the connection region. In order to permit secure attachment of the pressure medium lines even when the minimum thickness which is necessary for the use of the standardized connection thread is not present, the outside of the casing of the cylinder is flattened in the vicinity of the exit point of a duct provided for the supply of pressure medium. A connection plate which is provided with ducts for the pressure medium is secured to the flattened part of the casing, and the connection plate is provided with a port for a pressure medium line.