Abstract: In a conventional multiplunger transfer molding die apparatus having plungers for pressurizing molding material put in plural material supply pots formed in each mated surface of upper and lower chase blocks, when the pitch of the material supply pots is required to change, the whole die apparatus has been exchanged, thus a complicated adjustment work of the plunger pitch, a broad die storage space, an uneconomical die apparatus preparation being required. To overcome these problems, only the upper and lower chase blocks are exchanged and the pitch of plungers is adjusted according to the replaced chase blocks by means of locating means.

Abstract: A molding machine having a pair of separable mold elements forming a mold cavity therebetween is arranged for separation along a part-line. Means is provided for controlling the molded product which comprises means for measuring the separation of the mold elements resulting from the introduction of the moldable material into the mold cavity. Means is provided for detecting a predetermined separation of the mold elements, and means is provided for changing the pressure from the first pressure to the second pressure in response to the detection. The separation measuring means is arranged to measure the separation of the mold elements following changing the pressure. Means is provided for sensing when the separation of the mold elements stops increasing and for determining whether the cessation occurs within a predetermined cessation window. Means is provided to generate a signal if the cessation is not within the window to indicate that the cycle has exceeded the product limit.

Abstract: A method of operating an injection molding machine having a pair of separable mold elements forming a mold cavity therebetween with means for opening and closing the mold elements with means for introducing a moldable material into the mold cavity at a first pressure and for exerting a second pressure on the moldable material as it cures in the cavity. The method controls the molded product and comprises the steps of closing the mold elements and introducing a moldable material into the mold cavity. The separation of the mold elements is measured during the injection of the moldable material and a predetermined separation of the mold elements is detected. Upon detecting the predetermined separation the pressure is changed from the first pressure to the second pressure and the separation of the mold elements is continued. Measurement of mold element separation is continued and the cessation of the increase in the separation of the mold elements is detected.

Abstract: The invention relates to a method for producing insulations of foamed plastic material, in cabinets and doors of refrigerators, freezers and the like.According to the invention, a metered quantity of a foamable mixture is fed into the gaps between the inner and outer walls of a cabinet or door, placed in a foaming jig; the foaming process is controlled by sensing characteristic parameters, for example, the temperature of the jig, cabinet or door, or the pressure of the foaming plastic material, comparing them with reference parameters or data stored in a data processing unit. A control signal is generated to open the foaming jig and to unmold or remove the cabinet or door when at least one of the processing parameters has reached a pre-established value. The metered quantity of mixture fed in each subsequent foaming operation is corrected each time according to the changes in the peak pressure of the foam with respect to the previous foaming operation.

Abstract: Disclosed is a switching control system for a unit torque limit value of an injection molding machine servo motor (M) to limit a torque instruction (e) supplied from a servo circuit (8) to the servo motor (M) so as to optimize an injection pressure, a holding pressure, and a back pressure.During metering as compared with injection, an output level of a D/A converter (9) for receiving the torque limit instruction (g) is set to be smaller by a predetermined value to reduce the unit torque limit level. A unit torque limit value of the back pressure during metering is set to be smaller than the unit torque limit value for injection and holding pressures during injection, thereby setting smaller torque limit values during metering in units of smaller values as compared with the case of injection.

Abstract: A method for controlling back pressure in an electrically-operated injection apparatus wherein rotation and forward movement of an injection plunger within an injection heating tube are carried out by a first electric motor which provides a driving force, wherein backward motion of the injection plunger during the charging of material presses against a screw threaded rotatable part and is thereby converted into rotational motion of the threaded rotatable part, and wherein the rotational motion is controlled to control back pressure of the injection plunger. A second electric motor is used for controlling the back pressure on the injection plunger by controlling rotation of the threaded rotatable part. The backward force exerted on the injection plunger or the direct pressure of the molten material within the injection heating tube are electrically measured. By driving and controlling the second motor through feedback control, the back pressure is made to coincide with a set, preselected back pressure value.

Abstract: In the production of profiles from rubber and/or plastic mixtures, the throughput of the extruder should be kept constant. To this end, an identification of the mixture of material to be processed is fed in the form of a code to a computer system in which the characteristic mixture properties and the set-point operating values for a given profile to be made by the extruder are stored in memory. During the extrusion process, at least one operating variable, preferably the pressure occurring in the mixture of material being processed, is measured continuously, the difference between a measured value at a given time and the corresponding set-point value of the operating variable stored in memory is formed, and this difference is used as a control variable for a governing system for the speed or rpm of the extruder which is operated by the computer system.

Abstract: A sculptured structural fiberboard product is formed using a mold that includes porous forming areas which, in one embodiment, are porous forming mandrels movably mounted on the mold, and liquid impervious thimbles which removably cover the porous areas. A fiber network is formed as water is drained off through the porous areas and the thimbles are moved to gradually unveil the porous areas during the mat formation. When mandrels are used, the mandrels are withdrawn in cooperation with a pressing force applied to the mat to consolidate and dry the web. The porous areas can also act as heat and mass transfer means during consolidation and drying. An alternative embodiment permits formation of laminated products and another alternative embodiment permits close control over the product density during consolidation and drying.

Abstract: The present invention increases the shot capacity and the screw recovery time of an injection molding machine without increasing hydraulic pump capacity or motor horsepower. In accordance with one aspect of the invention, an existing injection molding machine is retrofitted with two cylinder and piston arrangements which are bolted onto the machine between its plasticizer barrel and its melt manifold. One of the cylinder and piston arrangements is employed to perform a mold-filling operation, whereas the other cylinder and piston arrangement is employed to perform packing and suck back operations.

Abstract: Method for adjusting the compression stroke allowance of a vertical injection-compression molding machine including a slide plate mounting thereon a mold clamp cylinder and an upper mold in opposition to a lower mold on a machine bed, and a lift cylinder for moving the slide plate up and down along tie bars, the method including the steps of: downwardly extending a piston rod of a hydraulic cylinder connected to the slide plate to a stroke end: upwardly extending a piston rod of an air cylinder connected to the bed thereof, with the upper and lower molds in contact with each other, until a micrometer at the upper end of the air cylinder piston rod abutts the lower end of the hydraulic cylinder piston rod; fixing the air cylinder piston rod in this state; upwardly retracting the hydraulic cylinder piston rod; setting the micrometer at a desired compression stroke allowance; lowering the hydraulic cylinder piston rod to the stroke end thereof; and lifting the slide plate so as to allow for injection-compression

Abstract: In a plastic processing machine (injection moulding machine) the amount of working medium to be supplied to the hydraulic drives and to the injection cylinder and the clamping cylinder is regulated to control the adjustment rates via a quantity control of an adjustment pump. The setting of the pressures necessary at the drives is effected in contrast via a directional valve which controls the fluid paths to one of the drives and which is adapted to be connected to the tank via a regulatable throttle point governing the pressure. This simplifies the apparatus expenditure for the pressure control of such a machine.

Abstract: Pressure is controlled in plural stages of a shaping system for a green tire in a curing press, so that each successive shaping stage is completed when a target pressure for that stage is reached. A radial tire is preferably shaped in three stages in the first of which a first target pressure in the range from 2 psig to 5 psig is the desired shaping pressure; in the second stage, a second target pressure in the range from 7-10 psig is desired; in the third stage, a third target pressure in the range from 10-15 psig is desired. A pressure transducer (PT) senses the pressure in a bladder, one PT for each bladder. A programmable controller (PC) which controls operation of the press, stores and executes a sequence of instructions which determine the optimum desired shaping pressure for each stage, computed from the type and size of the tire to be cured, the period of time the press is down before it is loaded, and the number of heats on each bladder.

Abstract: In order to obtain an injection drive apparatus which is low-priced, can produce a great output torque, and has a satisfactory acceleration/deceleration characteristic, in an injection-molding machine which performs injection by driving a screw by means of servomotors, one or more ball screws (7), used to drive a screw (2) in the axial direction, are driven by means of a plurality of servomotors (M1, M2), a position detector (P1) for detecting the screw position is provided only for one servomotor (M1), and the servomotors (M1, M2) are provided individually with power amplifiers, which are controlled by means of one control circuit so that the individual servomotors (M1, M2) are controlled in synchronism with one another.

Abstract: A method for continuously extruding an elastomeric material on the interior of a continuous tubular woven fabric in a loom, comprising motive means for creating relevant movement between the extruder and the woven fabric, sensing means for detecting stoppage of said loom, control means responsive to said sensing means directing said motive means to move said extruder relative to said woven fabric and a tubular woven fabric having an interior layer extruded directly onto the interior of the tubular woven fabric.

Abstract: The molding machine of the present invention comprises a screw extruder for extruding plastic material. A plurality of molds are moved one at a time to the outlet end of the extruder for receiving the plastic material therefrom, One end of the mold is open for receiving the plastic material and the opposite end of the mold includes a closure plate covering the end of the mold. The closure plate has a small fill sensing aperture therein. A sensing switch is mounted adjacent the fill sensing aperture and is adapted to sense when molded plastic exits from the fill sensing aperture so as to shut off the extruder and cause the mold to move away from the extruder so that an additional mold can be filled. A cylinder operated closure device clamps the opposite ends of the mold after the mold has moved away from the filling station so as to contain the plastic material within the mold while the plastic material cools and hardens.

Abstract: An injection molding machine generally comprises a heating cylinder, a screw rotated and reciprocated in the heating cylinder and a screw drive system. The screw drive system comprises two motors and two sensors connected respectively thereto which are automatically controlled by a control system in connection with a screw revolution number and a screw back pressure, or independently so as to accurately carry out the resin measuring process. The control system performs an adaptive control of a motion control system inclusive of the screw and the screw drive system in response to a screw speed instruction, a screw revolution number feedback signal, and a screw position feedback signal in accordance with various control modes.

Abstract: In an injection molding machine which injects molten metal into a metal mold cavity by an injection step and a succeeding pressure holding step, the injection step is controlled by the steps of filling the molten resin into the metal mold cavity at a high speed during the filling step; switching the injection operation from the filling step to the pressure holding step; concurrently operating braking means for applying a braking force to the plunger of the injection molding machine for stopping the plunger; and locking the braking means for continuously applying a constant force to the plunger until a gate seal of the metal mold cavity is completed.

Abstract: An injection mold comprises two or more mold sections, which enclose a cavity for molding an injection-molded part. The mold cavity is adapted to be supplied with the molding material through at least one entrance opening. The injection mold is maintained at a temperature at which the molding material is set. Said molding material is injected in a liquid state at a greatly differing temperature. To simplify the injection molding operation, to avoid damage by the removal of sprues, and to accelerate the manufacture,the molding material is injected through the entrance opening directly into the cavity by means of at least one injection nozzle. The injection mold comprises an injection nozzle having a nozzle tip which fits the entrance opening.

Abstract: A method for controlling the opening/closing of a mold in an injection molding machine providing an increased accuracy. A changeover position indicative of a speed of a movable plate or the changeover position of a pressure is preset in accordance with a corresponding position of the movable plate. The value thus set is arithmetically converted to a corresponding displacement distance of a rod of a mold-clamping cylinder. The converted value is compared with the detected displacement of the rod, and when the two values coincide, the hydraulic pressure controlling the mold is changed appropriately.

Abstract: A method for foaming and sintering of foamable plastic employing a control method based on the detection of the softening time point during the sintering steam application in the sintering process step. The softening time point is detected by analysis of a change in the rising speed of the pressure or temperature, and the related pressure and temperature values are used for determining the maximum dismission temperature and pressure of the sintered product. The sintering time is determined in relation to the softening time point and the quality demanded. A feed back control to the prefoaming and drying process step is provided. A feed back control by means of a quality measurement at the sintered part to the sintering is provided. Incremental controls are provided for adaptive process optimization.

Abstract: A molding apparatus for enclosing semiconductor chips with resin has a plurality of plungers for applying pressure to a resin material, at least one transfer channel holding each of resin material supplying pots in communication with corresponding one of cavities for transferring the resin material in a molten state, a communication bore formed in the vicinity of the transfer channel in communication therewith, slide members each intimately fitting in the communication bore and slidable forward or backward, pressing-pushing members for pushing each slide member toward the corresponding transfer channel with a uniform pressure, and a pressure sensor operable by the retraction of each slide member for detecting the internal pressure of the transfer channel.

Abstract: A curing press for tires, commonly manifolded to other curing presses in a curing room, are operated with a minimum blowdown time which is variable from one cycle of each press to another cycle. A first signal is generated by a pressure transducer ("PT") in pressure communication with the bladder(s) of each curing press; this first signal is compared to a second signal corresponding to a target pressure, which second signal is stored in a programmable controller ("PC"). The PC controls operation of the press, and is used to provide a variable blowdown period; how quickly this target in the PC is reached, is a function of the pressure in a common blowdown manifold for plural presses.

Abstract: The shaping device, particularly for an extruder tool or calibrator unit, for an extruder for thermoplastic material comprises at least one outlet defining an adjustably positionable unit lip, an opposing lip and at least one positioning member acting on the unit lip which is a part of a control and/or regulating mechanism for the thickness of the extruded product. The positioning member is a piezoelectric translator connected to a voltage source having a plurality of piezoelectric disks positioned opposing each other which are combined in a plurality of groups according to operation and according to electrical circuitry considerations. The groups of the piezoelectric disks individually and the sum total of several of the groups including the group containing all of the piezoelectric disks are connectable to the voltage source.

Abstract: A technique directed to a process for injection molding fiber-reinforced thermoset plastic articles is disclosed. The technique includes forming a mixture of short lengths of reinforcing fibers with a thermosetting resin in a predetermined fiber-to-resin ratio and introducing the mixture to an injection molding cylinder. The volume of mixture introduced is at least a multiple of two of the volume of the mold chamber so that the injection plunger traverses the intersection between the molding cylinder and a stuffer cylinder a single time for a multiplicity of molding shots to minimize fiber breakage and balling. The injection plunger is adapted to precompact the mixture by being forced forward until a predetermined high pressure is sensed, indicating a hydraulically locked condition of the plunger wherein substantially all entrapped gases have been expressed from the mixture and there exists no substantial forward movement of the plunger.

Abstract: An automatic press includes a first plate (2, 5), which is movable in translation along an axis, and a hydraulic jack (7), of which a piston (6) is secured to the first plate. The hydraulic jack commands the translation movement of the first plate to bring it into a first predetermined position (A) in relation to a reference postion (R1). The jack (7) is supported by a frame (3, 4, 8, 9). The press includes also a second plate (10, 12, 13), which supports an object (30) to be pressed; this second plate is situated facing the first plate. The jack (7) includes a mechanism (41) for bringing into control the position of the plate with the set predetermined position (A), and an opto-electronic member (16) for referencing the momentary positions of the first plate in the course of its movement. The automatic press has application to the manufacture of objects by pressing and also to welding done by bringing the plates together.

Abstract: A method particularly suitable of monitoring the production of elongate profiles which are formed from one or more mixtures of rubber or thermoplastic material in an extrusion head which is fed by one or more extrusion devices is disclosed as in an apparatus which is particularly suitable for carrying out such a method. During production, the strip passes through a cooling path or station in which longitudinal shrinkage thereof occurs. The desired shrinkge is known and the actual shrinkage is monitored by suitable means. These means are operatively connected to a regulating or control device. When leaving the head, the profile passes over a weighing device which determines the weight per unit length thereof. The weighing device is also operatively connected to the regulating or control device. If a deviation from the desired shrinkage in the zone or station is ascertained, the regulating device sets a new, corrected, desired weight per unit length value to be achieved at the weighing device.

Abstract: A rotation control system for a screw of an injection molding machine is so arranged that an injection shaft 2" and a screw (2) are driven by electric motors (20) and (22). An output signal from an injection shaft position sensor (21), which provides information indicative of rotation of the electric motor (22) driving the injection shaft 2", is applied to an error register (35-1). The position of the injection shaft is sensed by monitoring the error register (35-1), and the rotational speed of the screw (2) corresponding to the position of the injection shaft 2" is obtained by utilizing an override function.

Abstract: Plastics-forming materials are shaped in a mold tool sealed by an associated closing unit. Lifting elements the stroke of which can be limited and controlled are associated with the mold tool. Shaping is accomplished by filling the mold cavity with reaction mixture while the mold tool halves are not completely sealed, sealing the filled mold and keeping the mold sealed until the article is completely cured. This method and apparatus are particularly useful in the production of dimensionally accurate geometrically complicated shaped articles.

Abstract: A hydraulic control system for the operation of three linear and one rotary hydraulic drive assemblies of the injection unit of an injection molding machine, comprising a variable delivery pump supplying drive fluid at a constant pressure gradient to several supply lines controlled by two control units which are arranged in parallel and feature proportional P/Q valves and pressure transducers, a smaller pressure maintenance pump which is controllable by a third proportional P/Q valve and switchable into one of the supply lines, and a hydraulic accumulator for the temporary supply of a large quantity of drive fluid. The proportional P/Q valves convert automatically from their flow rate programs, controlled by displacement-to-voltage converters on the injection unit, to pressure programs controlled by the pressure transducers.

Abstract: Extrusion apparatus for conductor wire in which a core tube for guiding the wire is controllably movable axially so as to adjust the cross-sectional area of the flow passage for molten polymeric dielectric material moving towards the die orifice. The use of the adjustable core tube minimizes the degree of draw down of the conductor wire.

Abstract: In the extrusion apparatus for plastics foil, a smoothing rolling mill (2) is allocated to a device (1) for extruding a soft, warm plastic, in the plasticizing cylinder (3) of which, the plastic is brought to processing temperature and from this conveyed out through a fishtail die (6) by means of a conveyor screw (5), whereby a displaceable filter band (8) is inserted before the fishtail die. In this connection, the filter band (8) has a width of at least approximately the inlet-side width of the fishtail die (6) and is displaceably situated at right angles to the longitudinal extension of the die (6).Through these measures, an extension apparatus for manufacturing foil out of plastic results, which permits with low filter consumption and optimal and functionally reliable control, the manufacture of a high-quality foil.

Abstract: The invention is directed to a process for dotting molding tools with droplets of liquid or suspended lubricant in the production of shaped articles in the pharmaceutical, food, or catalyst fields. Pressurized lubricant solutions or suspensions and pressurized gas are alternately passed through capillaries, in conjunction with alternating single-substance nozzles, in such a way that drops are formed on the nozzle surface, in between the jets of gas, and are then detached form this surface and directed to specific zones of pressing tools. The apparatus comprises fast-acting valves for the brief release of pressurized gases and lubricant liquids or suspensions. The delivery lines of a gas valve and a liquid valve combine upstream of a capillary, and single-substance nozzles are mounted at the end of the capillaries.

Abstract: A mold opening/closing speed control device wherein an opening/closing speed switching position for molds in a mold clamping unit in an injection molding apparatus can be taught by the control device. The control device is set in a teaching mode (101), a servo motor (M) is driven at a low speed to move (102) the molds, speed switching positions P1, P2 and P3 are stored (103, 104, 205, 106, 109) by a teaching device, and the opening/closing speed control of the molds is performed (110, 123) by the servo motor in accordance with the stored positions.

Abstract: An injection molding machine for small-sized articles of thermoplastic synthetic resin comprises a hydraulically pressurizable injection head cylinder operable on an injection cylinder of an injection unit for injecting molding material into a mold, a hydraulically pressurizable clamping cylinder operable on one of a pair of mold members of the mold for opening and closing the mold, and a booster operatively connected to both the injection head cylinder and the clamping cylinder for converting pneumatic pressure into high hydraulic pressure to actuate the two cylinders in timed relation to each other.

Abstract: The invention includes a method and an extrusion apparatus for shaping plastic materials particularly those of high molecular weight, whereby the temperature distribution in an extrusion cylinder allows for the build-up of very high pressures and all axial pressure forces are absorbed by a two-sided extruder screw, the extrusion cylinder and, in some instances, the therein contained plastic material. In practicing the method, the plastic material in a flowing state, and at a positive pressure, is continuously conveyed to an extrusion apparatus, and subsequent to its entrance in an extrusion cylinder and before its discharge is cooled to a temperature below the solidification point, not only from the outside by a cooling source in the extrusion cylinder but also from the inside by a cooling source in the interior of the extruder screw.The present invention makes possible the production of materials of improved strength and elasticity, which can be molded to synthetic threads, films and splittable films.

Abstract: A process is provided for controlling a thickness regulating member such as a slice lip coupled to slice rods. The process includes determining the desired configuration of the slice lip and determing the required slice rod movements based upon physical characteristics of the slice lip and the slice rods.

Abstract: A circular pelletizing machine for compressing of powder or grain materials, comprises a rotatable matrix disc with a plurality of circumferentially distributed matrices, upper and lower punches located above and below the matrix disc respectively, at least two pre-pressing elements movable relative to one another and acting upon the upper and lower stamps so as to pre-press pellets of a material, at least two main pressing elements movable relative to one another and acting upon the upper and lower stamps so as to finally press the pellets of the material, an adjusting motor arranged to adjust a distance between the main pressing elements relative to one another, computer device arranged to control the adjusting motor, and device for measuring a pressing force of the pre-pressing elements and supplying data of the measurement to the computer device so that the computer device controls the adjusting motor and therefore the distance between the main pressing elements in dependence upon the measured pressing fo

Abstract: A molten resin to be injected into a mold cavity in use of an injection molding machine has a temperature, i.e. viscosity difference between at the injection starting point and the injection completing point. In order to eliminate or make small this difference, a high temperature and highly pressurized gas, preferably an inert gas, is preliminarily supplied to and sealed in the mold cavity and the pressure of the supplied gas is continuously controlled in accordance with the position of the screw during the injection molding operation thereby to maintain the temperature of the supplied gas in the mold cavity to be higher than the softening temperature of the molten resin to be injected.

Abstract: A method of molding and coating in a mold a thermosetting substrate including the steps of forming the substrate between at least two separable dies which form a mold cavity therebetween, curing the substrate to the point that the substrate is receptive to a coating, injecting the coating into the mold cavity at a pressure substantially in excess of the mold cavity pressure while maintaining the dies in position whereby the coating is forced over the desired surface of the substrate and curing the coated substrate.

Abstract: A method and apparatus for controlling induced dynamic instability in an axially moving form supported between two axially spaced supports wherein the form is relatively soft and therefore exposed to development of transverse tensional forces tending to pivot the form about one or both supports. Control is effected by establishing a datum axis, repeatedly sensing the lateral position of the form in at least two mutually inclined transverse directions, deriving signals proportional to the sensed lateral displacement of the form from the datum axis, converting the signals to thrust forces, and applying the thrust forces to restore the form to the desired lateral position. The technique is of particular value in the production of oriented polymeric tubular films.

Abstract: Folding elements for forming gussets in a tubular film are provided in the mutually opposite open areas between a pair of flattening plates and the plates are reciprocable in the axial direction of the tubular film for an adjustment of the depth of the gussets. The folding elements are mounted to be pivotally movable in all directions and are guided to be transversely displaceable relative to the axis of the tubular film. Adjacent to their mutually opposite, upstream ends the folding elements are provided with adjusting means for imparting a pivotal movement which is transverse to the direction in which the depth of the gussets is adjusted and/or about their longitudinal axes in dependence on a measured deviation of the outer fold lines from their desired position. Sensors are provided for detecting the location of the outer fold lines of the gussets formed in the tubular film.

Abstract: An injection molding apparatus including a barrel for holding molten plastic material, a first passage connected at one end with the barrel for receiving hot plastic material from the barrel, a second passage connected with the other end of the first passage for receiving molten material from the first passage for supplying the material to a mold, a cylinder, a third passage connected at one end with the cylinder and connected at its other end with the second passage, a piston in the cylinder, movable by pressure means in one direction to maintain pressure on molten material in the cylinder, the third passage and the second passage, and movable by pressure means in the other direction to exert a suction action in the cylinder, the third passage and the second passage for drawing molten material in the second passage back into the third passage and the cylinder, and a valve means.

Abstract: An improved, low cost, energy efficient extrusion device and method for processing of cellulose- or fiber-bearing materials (e.g., wood chips, crop residues, whole or ground soybeans) is described which includes a transition screw section designed to smooth out material flow through the extruder and allow creation of increased barrel pressure and temperature levels. The transition section includes first and second alternating flights, with the depth of the first flight being less than that of the second flight and preferably gradually increasing until it equals the second flight depth. The overall extruder apparatus also advantageously includes a single flighted inlet screw section and a double flighted compression screw section respectively disposed on opposite sides of the transition section; in addition, the extruder has a pressure responsive adjustable die so that the effective dimensions of the die opening can be varied during the extrusion operation.

Abstract: Disclosed is a hydraulically controlled extruder injection molding unit which includes a measured value pick-up for the position of the piston rod of the working cylinder and/or of the injection piston. A pressure control valve which can be switched on is provided in the line leading to the surge chamber of the working cylinder for the piston. A proportionally controlled pressure valve is provided in the line to the other surge chamber, the value being controlled as a function of dropping control values when switching from subsequent pressure to dynamic pressure until the measured value pick-up emits an output signal. The then existing instantaneous value of the dynamic pressure is then added to the preselected dynamic pressure. Consequently, the dynamic pressure phase takes place under a corrected dynamic pressure.

Abstract: Accurate dimensional control in ultrasonic welding or upsetting of plastic parts is accomplished by the method and apparatus for monitoring the ultrasonic head displacement and sensing when a predetermined trigger force is applied to the part or parts, turning on the ultrasonic energy at the trigger point and terminating the ultrasonic energy when head displacement from the trigger point reaches an empirically established value, holding the force for a hold time and measuring the maximum displacement value at the end of the hold time, releasing the force when the force returns to the trigger point, measuring the overall displacement, and determining whether the overall displacement is within allowable tolerance values. Weld time and weld energy as well as the overall head displacement are monitored for comparison with preset tolerance values to determine acceptability of the part being processed.

Abstract: The molding machine of the present invention comprises a screw extruder for extruding plastic material. A plurality of molds are moved one at a time to the outlet end of the extruder for receiving the plastic material therefrom. One end of the mold is open for receiving the plastic material and the opposite end of the mold includes a closure plate covering the end of the mold. The closure plate has a small fill sensing aperture therein. A sensing switch is mounted adjacent the fill sensing aperture and is adapted to sense when molded plastic exits from the fill sensing aperture so as to shut off the extruder and cause the mold to move away from the extruder so that an additional mold can be filled. A cylinder operated closure device clamps the opposite ends of the mold after the mold has moved away from the filling station so as to contain the plastic material within the mold while the plastic material cools and hardens.

Abstract: A method of molding a composite material comprising reinforcing fibres enclosed in a resin matrix. Layers of the resin impregnated fibres are laid-up in a suitably shaped die whereupon the laid-up layers are overlaid by a silicone rubber member which generally corresponds in shape with the die. Hydraulic pressure is exerted upon the silicone rubber member so that it urges the laid-up fibres into the configuration of the die. The whole molding apparatus is placed in an oven and its temperature is raised to that at which consolidation of the laid-up fibres occurs and the resin cures. The exerted hydraulic pressure is progressively reduced during heating as the silicone rubber member thermally expands so as to ensure that the pressure exerted by the silicone rubber member upon the laid-up fibres remains substantially constant.

Abstract: Providing an insulation layer upon electrical conductor by passing the conductor with clearance towards and through an outlet orifice of a die insert as the conductor approaches a die orifice. The degree of concentricity of the conductor within the insulation layer is monitored after extrusion and an eccentrically positioned conductor is moved towards a concentric location by moving the conductor, at a position upstream of the outlet orifice of the die insert, laterally of the feedpath. This movement effects a change in approach of the conductor to the outlet orifice and influences a change in the angle of departure from the outlet orifice thereby altering the lateral position of the conductor within the die orifice.

Abstract: A mold closing unit of an injection molding machine has a hydraulic traveling cylinder and a hydraulic mold closure retention cylinder for the movable mold clamping plate. One-half of a divided injection mold is clamped on the plate and defines with a fixed mold die a mold cavity having a larger volume at the commencement of the mold charge than at the termination of the mold charge. A threaded spindle is engaged with the movable mold clamping plate through a spindle nut, and the spindle is freely rotatable in the stationary mold clamping plate and is connected with a stepping motor. A 4/2-way valve is arranged in the hydraulic supply line leading to the traveling cylinder, and its valve body is axially shiftable on the spindle. The stepping motor is controlled depending on a specified pressure and/or speed pattern as a function of the distance between the mold halves or the mold clamping plates.

Abstract: There is provided a hydraulic motor-driven extruder having raw rubber stock fed from coiled continuous strips into the extrusion portion thereof. The extruder includes a screw shaft and housing having decreasing diameter as material is transported toward the discharging extremity thereof. Surrounding this screw extruder there is provided heating bands of controlled temperature to impart additional heat. On discharge from the extruder the prepared rubber is deposited within an expandable cavity for selecting the desired volume of prepared rubber material. Once measured the prepared rubber is lifted from the cavity for insertion into the molding press.