Abstract: The invention relates to a linear drive device for opening and closing molding tools and for applying a clamping force thereon, especially mold halves of a plastics molding machine. The device is comprised of a screw drive acting upon the molding tool, a first screw nut for opening and closing the molding tools and a piston/cylinder unit for applying a clamping force. In order to provide a linear drive device for opening and closing molding tools, especially mold halves of a plastics molding machine, which enables fast opening and closing of the molding tools and energy-optimized application of the clamping force to the molding tools, the piston/cylinder unit (113) acts upon the molding tool by means of a second screw nut (108).

Abstract: An injection molding device includes a continuously operating extruder and a discontinuously operating injection unit receiving plastic material from the extruder. The extruder has an extruder barrel which includes a plasticizing zone and a discharge zone, whereby the discharge zone is configured to provide an intermediate storage space and has a cross sectional area which is greater than a cross sectional area of the plasticizing zone. In this way, the discharge zone provides a buffer volume which is filled during the injection process and then emptied again.

Abstract: An injection molding machine includes a stationary platen, a movable platen constructed for movement relative to the stationary platen, at least one tie bar for tension-proof connection of the fixed and movable platens, and a traction transmitting securing device including a securing element, disposed on a rear side of one of the platens, for interacting with the tie bar within an engagement zone. The securing element and the tie bar are provided with a number of projections and recesses in axial spaced-apart relationship to establish a form-fitting connection, whereby the projections and the recesses are pressed together when exposed to a tensile stress and interlock at an axial clearance which increases along the engagement zone in axial direction corresponding to the tensile stress of the tie bar.

Abstract: In a two plate closing unit of an injection molding machine the stationary and the movable mold mounting plates are connected by columns, wherein the columns that traverse the fixed mold mounting plate are fixedly connected to a clamping cylinder in which the columns configured at their ends as pressure plungers configured for generating a clamping pressure reciprocate, and while some of the clamping plungers are dual action plungers, the clamping plungers are coupled to a spindle drive and drive unit, such that the spindle drive is at the same time the control drive for a stepped plunger and the closing force and the closing and opening motion is realized by a single drive which operates the spindle and the plunger cylinder unit.

Abstract: In a method of making impact-resistant modified thermoplastic materials, thermoplastic material is introduced in a continuously operating twin-screw extruder having two screws rotating in a same direction and plasticized. Admixed to the thermoplastic material in the extruder at a location well downstream of the feed area of the thermoplastic material is an additive, e.g. impact-resistant modification agent, reinforcing agent, or alloying agent, to produce an extrudate which is conveyed for injection into an injection mold alternately via two injection cylinders or via a storage cylinder and one injection cylinder.

Abstract: To displace a moving mold mounting plate (3), a threaded spindle drive is inserted between the moving mold mounting plate (3) and a fixed mold mounting plate (16), whereby one end of each threaded spindle is mounted in the fixed mold mounting plate (16) and is configured as a piston (9) of a hydraulic piston and cylinder unit. The pistons are mounted in the fixed mold mounting plate (16) in hydraulic cylinders and an increased clamping force is created for the platen clamping mechanism by an appropriate impingement of the piston (9). In addition, the invention provides a detachable anti-rotation mechanism (23) for the threaded spindles (15). The invention thus allows an inclined position of the mold mounting plates (3, 16) to be corrected, by the targeted rotation of one or more threaded spindles.

Abstract: A rotary device for a horizontal injection molding machine is configured in the form of a module frame which includes a base plate and a turntable rotatably mounted on the base plate. Drives are provided to move the base plate in longitudinal direction and to rotate the turntable. A fixed mold mounting plate of the injection molding machine can be mounted on a mounting structure of the module frame, whereas a moveable mold mounting plate is received in guides along the sides of the module frame.

Abstract: A mold closing device for an injection molding machine has four tension members (17, 19) which interconnect the fixed mold closing plate (3) and the support plate (5) of the closing drive (7) in a tension-resistant manner are not formed as straight rods but have a L-shaped configuration, with each tension member (17, 19) being connected at an upper connection point (21, 25) to one plate (5, 3) and at a lower connection point (23, 27) to another pate (3, 5). The upper edge (33) of the tension members (17, 19) is positioned at a lower level than the closing pressure axis (11) in order to ensure a free access to the space between the mold clamping plates. The tension members (17, 19) are of exactly same shape and dimension so as to extend by the same amount when being subject to the closing pressure in order to maintain parallel disposition of the fixed clamping plate (3) and the support plate (5).

Abstract: An apparatus for closing a mold having a pair of mold halves has a housing, a fixed support block on the housing carrying one of the mold halves, an abutment block on the housing, and a support block movable on the housing between the fixed support block and abutment block in a direction toward and away from the fixed block and carrying the other of the mold halves. A frame has at least one plate lying in a vertical plane generally parallel to the axis and formed with a pair of stiff upwardly extending upper arms, a pair of stiff downwardly extending lower arms below the respective upper arms, and an elastically deformable web extending in the direction between the upper arms and the lower arms. Anchors, e.g. bolts, fix one of the upper arms to the fixed support block and the other of the upper arms to the abutment block.

Abstract: An injection molding machine has a pair of C-shaped tension members interconnecting the fixed bracing plates at location above the axis of force action in the mold closing and injection operations. The mold closing unit is mounted on one of these plates and a mold part on the other plate while the mold closing unit acts on the movable mold part. According to the invention, the fixed plates are also interconnected by lower tension members which can be C-shaped or can be tension rods so that access to the space between the mold parts remains available, the upper and lower tension members being matched as to elongation under the generation of the mold closing and injection forces.

Abstract: A mould closing device for an injection moulding machine includes a fixed (1) and a movable (4) mould clamping plate for support of screw drives (36) which are freely rotatable in the fixed mould clamping plate (1) and axially supported in one direction and supported in spindle nuts (39) secured in the movable mould clamping plate (4). Provided for actuation of the screw drives (36) for the closing and opening stroke of the movable mould clamping plate (4) are a rotary drive (44) and a hydraulic piston-cylinder unit (45, 46) interacting with the screw drives for effecting the closing force build-up.

Abstract: A molding system has a base, a fixed mold plate secured to the base, a fixed mold half carried on the fixed mold plate, a movable mold plate displaceable on the base longitudinally forward away from the fixed mold half and backward toward the fixed mold half, and a movable mold half carried on the movable plate and fittable with the fixed mold half. A mold-closing apparatus has a pair of main cylinders fixed to the fixed mold half and respective main pistons subdividing the main cylinders into respective front and rear main compartments and each having a piston rod secured to the movable mold plate and formed with a longitudinally extending chamber. A small-diameter fast-closing piston and cylinder are formed in one of the piston rods, and the other piston rod is provided internally with a force-amplifying piston unit. Two flow-control valves and check valves control the system.

Abstract: A mold closing apparatus and process for use with an injection molding machine are described. The mold is opened and closed by hydraulic pressure. The disclosed apparatus and method relate to the use of an immobile differential piston within a displaceable, double-action differential piston which moves within an immobile piston cylinder. This arrangement permits the use of smaller diameters to produce the necessary closing force. The immobile differential piston contains the necessary hydraulic passage for routing hydraulic fluid to the appropriate surfaces for exerting opening and closing forces. The use of a plurality of displaceable, single-acting pistons in parallel with the differential piston further reduces the diameters needed for exerting the claim force. Locating these single-acting pistons within the support column cylinders makes for an ever more compact apparatus.

Abstract: A mold closing apparatus and process for use with an injection molding machine are described. The mold is opened and closed by hydraulic pressure. The disclosed apparatus and method relate to the use of an immobile differential piston within a displaceable, double-acting differential piston which moves within an immobile piston cylinder. This arrangement permits the use of smaller diameters to produce the necessary closing force. The immobile differential piston comprises the necessary hydraulic passages for routing hydraulic fluid to the appropriate surfaces for exerting opening and closing forces.The use of a plurality of displaceable, single-acting pistons in parallel with the differential piston further reduces the diameters needed for exerting the closing force. Locating these single-acting pistons within the support column cylinders makes for an even more compact apparatus.

Abstract: A drive apparatus useful in screw injection molding apparatus is disclosed. The apparatus is particularly useful when both axial and rotational movements are required because the invention discloses a construction that reduces the wear attributed to sealing gaskets of relatively large diameter which are subjected to rotational stresses and relatively high linear velocities. In the injection molding embodiment described in detail, the extruder screw is rigidly attached to a drive piston that has both axial and rotational movements. Concentric to that drive piston is a drive cylinder tha has only axial movement yet is connected to the drive piston such that the piston is able to rotate freely relative to the cylinder but may move axially only when the cylinder moves. Thus, the sealing gaskets of the drive cylinder are free of rotational stresses which extends the useful life of the sealing gaskets.

Abstract: An apparatus for closing a mold in an injection-molding operation has a double-acting main piston that is connected to a mold-carrying plate and that move axially in a main cylinder. A rapid-action piston extends into a small-diameter bore in the main piston, and the rear cylinder wall is formed with a large-diameter fill passage connected directly to a sump. A positioning cylinder is fixed on the main cylinder and contains a positioning piston axially fixed on the rapid-action piston and having in the positioning cylinder a rearwardly directed face larger than the face of the rapid-action piston and forming with the positioning cylinder a pressurizable positioning chamber. A passage extends axially through the rapid-action piston from its cylinder to the positioning chamber.

Abstract: A three-way or three-ported flow-regulating valve for use in a hydraulic system comprises a two-position two-ported throttle valve inserted between an inflow conduit and an outflow conduit and a pressure-relief valve connected to the inflow conduit at an upstream point thereof and at a downstream point proximate to an intake port of the throttle valve. A servovalve is connected in parallel to the throttle valve via small-diameter pressure-transmission channels extending to the intake port and to an output port of the throttle valve. Upon a jump in the pressurization of the inflow conduit, for example due to the activation of an auxiliary pump, the pressure-relief valve opens; it closes again only upon an equalization of the pressure throughout the inflow conduit. The servovalve has a biasing spring which exerts a force determining the maximum pressure drop across the throttle valve.

Abstract: A mold-closing device for an injection-molding machine has a main piston connected to the mold-carrying plate of a movable mold half and is provided with a pressure-multiplying piston which closes a passage between sides of the main piston to render effective the differential action of the multiplier piston. The multiplier piston can be shifted prior to the main piston by a time-delay device in the pressure lines and/or by a mechanical element.