Abstract: The improved electrofusion joint and header for supplying hot water that perform satisfactorily at elevated temperatures as evidenced by high heat resistance, that exhibit good sealing property and that can be handled efficiently in mounting and various other operations have a crosslinked thermoplastic resin layer and at least one joining portion which comprises a non-crosslinked thermoplastic resin layer that is formed a as an integral part of said crosslinked thermoplastic resin layer in the area where it contacts a tubular member to be joined, and a heating electric wire provided either within or on the outer or inner surface of said non-crosslinked thermoplastic resin layer. Such electrofusion joint and header are applicable to any part of a piping system for supplying hot water and they will withstand use for a prolonged period.

Abstract: An open tube apparatus and method for continuously producing a rotating elongate strip of material are disclosed. An extrusion die continuously extrudes flowable material to form an open tube with a central longitudinal cavity and a transport mechanism includes a plurality of drive rollers which engage and pull the tube downline. A driver rotates the extrusion die and transport mechanism. A tube cutter, which is offset at an angle with respect to the downline direction and defines the open end of the tube, cuts the tube into a continuous elongate web of the desired width as the tube moves downline. An air seal seals the tube cavity to prevent air from escaping through the open end of the cavity, and a tube pressurizer controls air pressure in the central longitudinal cavity of the tube to expand the tube laterally outwardly.

Abstract: This invention relates to an injection pressure control apparatus for a die cast machine and an injection mold machine. In the injection pressure control apparatus, it detects whether the pressure increase state of the instance when the pressure of the injection cylinder is increased through a pressure increasing circuit is normal or not. When detecting the above state, the pressure change obtained at the instance when the pressure increasing circuit is operated is detected between two points, of which it is determined whether the time spent therebetween is within an allowable time or not and the result is indicated. Moreover, the pressure detected after the pressure increasing circuit was operated and a predetermined period of time has passed is determined whether it is within a predetermined allowable range or not and the result thereof is indicated.

Abstract: Uniform spherical granules are produced from powder raw material without utilizing an agglomerating liquid by repeatedly and alternately compacting a dry powder raw material within a granulating vessel to cohesively form agglomerates of the material and fluidizing the powder material within the vessel to break up and form the agglomerates gradually into a uniform spherical shape.

Abstract: A constraining structure for an open tube apparatus for continuously producing a rotating elongate strip of material is disclosed. The constraining structure controls expansion of an extruded blown film tube to a desired outer diameter range after the tube is formed. The constraining structure includes a casing positionable around the tube, and an annular sleeve in the casing having a generally cylindrical central passageway adapted to receive the tube to permit movement of the tube along its longitudinal axis in a downline direction. The casing and the sleeve walls define a gas chamber with pressurized gas separate from the passageway. The gas layer along the inner surface of the sleeve is at a sufficiently large pressure to constrain the tube to the desired outer diameter while the tube solidifies and to prevent the tube from contacting the sleeve.

Abstract: A method and apparatus for providing gas assistance in a resin injection molding process of the type in which hot resin is injected into a mold, gas is injected into the mold to displace a portion of the resin in the mold, the resin cools, the gas is vented, and the mold is opened to remove the molded part. The apparatus includes a high pressure gas storage system, a plurality of pressure control assemblies set at varying pressures and interposed between the high pressure gas storage system and the injection nozzle, and a control system which is operative to selectively communicate each of the pressure control assemblies with the injection nozzle so as to allow the delivery of gas at varying pressures to the mold to facilitate the creation of an individualized gas pressure profile to suit the particular molding requirement.

Abstract: A method and apparatus for moulding a fluid settable material. The apparatus includes male and female mould halves defining between them a mould cavity having an inlet thereto for the introduction of a fluid settable material; between the male and female mould halves of the cavity a seal can be interposed to seal the mould cavity from the atmosphere. At least one vacuum outlet from a mould half leads via an isolation valve to a vacuum source.

Abstract: A method of manufacturing a porous static pressure gas bearing includes the steps of impregnating a porous material to be adjusted in injection flow rate with resin and closing vent openings, and applying a solvent for dissolving the resin to the porous material through a pattern having a predetermined opening distribution.

Abstract: A method is described in which the operative condition of the cooling sections of a slot die for making flat films of thermoplastic material, or of an annular die of a blow molding extruder for making tubular films from synthetic thermoplastics, is tested. The cooling sections are provided with lines for supplying and discharging cooling air and the lines for supplying cooling air are connected, as required, to a central cooling air feed line, which is under superatmospheric pressure, by solenoid valves controlled by an electronic computer. In one embodiment of the invention, a testing program is performed in which the cooling air feed line is disconnected by a shut-off valve from the branch lines leading to respective solenoid valves when the latter are closed.

Abstract: In a method for making objects of foamed, thermoplastic synthetic substance, air pressure is maintained in the mold while it and the contained plastic particles are heated, said air pressure being equal to or slightly higher than the pressure of the steam used for heating. When the mold has reached the saturated steam temperature, the air pressure is reduced to fuse the prefoamed synthetic particles together. Thereafter steam is introduced to displace the air in the mold and heat the synthetic particles to the temperature required for fusing or sintering.

Abstract: Cold carbon-containing blanks which are impregnated with a carbon-containing material are introduced into a cold autoclave which is thereupon sealed and filled with inert gas prior to heating of the interior of the autoclave to tempering temperature. The tempered products are cooled in and thereupon removed from the autoclave, and the inert gas is relieved of hydrocarbons and other harmful substances which are released by the impregnating material during tempering.

Abstract: A method for continuously controlling the pressure in a bubble formed of a continuously extruded seamless blown thermoplastic film tubing which is being conducted generally upwardly through a cooling water bath. More particularly, the method contemplates controlling the internal bubble pressure through the intermediary of a Photohelic pressure controller which is utilized to monitor the differential prevailing between the internal bubble pressure and that of the water bath encompassing the bubble. The invention also relates to an apparatus for controlling the internal pressure of a bubble constituted from a seamless blown thermoplastic film which is extruded and conducted through an external cooling water bath, employing the method pursuant to the invention.

Abstract: A molding condition recording apparatus having a manual data input device with a CRT. The manual data input device has various keys for inputting parameters of various groups used for controlling injection, hold, metering and cylinder temperature, and for inputting molding defect indication data. A microprocessor for a programmable machine controller causes the input parameters and the molding defect indication data to be stored in a molding condition storage region of a shared memory (S5). The microprocessor then discriminates similarity between the thus stored molding condition and the molding condition already registered in a molding condition/molding defect storage file of a memory other than the shared memory (S7). If there is similarity between these molding conditions, the microprocessor causes the CRT to display an alarm message thereon together with the parameter already registered in the file and the mold defect indication data (S12).

Abstract: Apparatus for producing, from rubber and/or plastic mixtures, thin wall tubes for bicycle and motorcycle tires includes an extruder followed by a belt conveyor for transporting the extruded tube blank from the extruder, a scale for weighing the tube blank, another belt conveyor, rolls for forming the blank to a predetermined cross sectional shape and a light source on one side of the tube blank and a light receiver on the opposite side of the tube blank for measuring a transverse dimension of the shaped tube blank and thereby its circumferences. A blower supplies to the interior of the tube blank a mixture of air and powder which is removed by an exhaust blower which is regulated to control the air pressure in the tube blank. The rate of withdrawal of the tube blank from the extruder by the conveyor and the air pressure inside the tube blank are controlled by outputs of the scale and the transverse dimension measuring light receiver.

Abstract: A process is provided in which a plasticized resin is extruded from an extruding machine into an accumulator into which the resin is stored by an amount which exceeds the amount required for one resin molding operation. The stored resin, in operation, is fed through a flexible hose to a supply and measuring device, such as a gear pump, under controlled pressure conditions. The resin is measured by the supply and measuring device by regulating the flow rate of the resin and is then charged into the mold cavity in a measured amount. The clamping of the mold can be effected by a clamping force less than that required by a conventional press-molding machine.

Abstract: A process and apparatus is provided for explosively forming plastic objects from shredded plastic such as recycled plastic having different compositions. The shredded plastic and an explosive gas mixture is introduced into a mold cavity having the shape of the object to be formed, and the gas mixture is ignited, generating sufficient heat and pressure to force the plastic to conform to the shape of the mold cavity. The temperature and pressure in the mold cavity is controlled during the explosion by releasing combustion gases from the mold cavity.

Abstract: A method and an apparatus of injection molding articles of thermoplastic material. The method includes initially forcing molten plastics material into an injection mold in an amount sufficient for forming the article. Subsequently, a flowable medium is forced into the injection mold with a pressure which distributes the plastics material uniformly over the surface of the mold cavity of the injection mold so as to form a hollow body. The hollow body is then cooled while the pressure of the medium is maintained. Finaly, the pressure of the medium is released and the molded article is removed from the injection mold. The pressure of the medium in the mold cavity is controlled and/or varied at least temporarily until the plastics material has cooled. The apparatus for carrying out the method includes a pressure reservoir for the medium which is connectible to the injection mold through lines. The lines include control and/or regulating elements.

Abstract: A method and apparatus for gas assisted injection molding. The apparatus includes a bulk storage container; a booster receiving the gas from the bulk storage container and operating to boost the pressure to a relatively high level for delivery to a high pressure storage container; a regulator receiving the gas from the high pressure storage container and reducing the gas pressure to a desired injection pressure; and a control system for injecting the gas into the mold, at the injection pressure as determined by the regulator, thereafter reducing the gas pressure within the mold to a hold pressure, thereafter maintaining the gas in the mold at the hold pressure, and thereafter venting the mold to atmosphere. The apparatus allows the performance of two distinct injection molding methods. In the first method, the regulated gas is injected directly into the mold, is held at the injection pressure during the fill out portion of the molding cycle, and is thereafter reduced to a hold pressure.

Abstract: An optimum molding condition setting system for an injection molding machine comprises a molten material flow analysis component for analyzing resin flow, resin cooling and the structure/stength of molded products by using a designed mold model and also comprises an analysis result evaluation component for determining an initial molding condition and its permissible range in accordance with the analysis results. The initial molding condition is set into the injection molding machine and a test shot is carried out in order to check for a deficiency of a molded product. If a deficiency of the molded product is detected, a data of the deficiency is entered into a molding defect elimination component. After performing a convenient data processing based on the entered data, a cause of the molding defect can be inferred and a measure for the cause can be obtained with high efficiency and accuracy.

Abstract: An apparatus for making a fleece comprises a horizontally elongated upright passage, flaps defining a stretching gap between the walls, and respective lower flaps have upper edges pivotal by actuators on the walls. A foraminous conveyor belt extends horizontally immediately underneath the passage and is advanced generally continuously horizontally past the passage. An array of spinnerets in the upper end of the passage forms filaments that move downward in the passage and that deposit on the moving conveyor as cool air is introduced into the upper end of the passage and is withdrawn from the passage through the lower end thereof and through the foraminous belt. The deposited length of the filaments on the belt downstream of the lower passage end is continuously monitored and an output corresponding thereto is generated and is compared with a set point and the lower flaps are pivoted to move their lower edges away from one another when the output of the sensor means exceeds the set point and vice versa.

Abstract: An automated, close-loop system for controlling the autoclave cure of fiber reinforced composites uses multiple expert systems hosted on different microprocessors running concurrently to control the cure process. This qualitative process controller uses sensory feedback to determine matrix material state-of-cure and then makes control decisions and executes control commands to the autoclave to attain desired material properties. The sensory information is interpreted and translated into a qualitative cure-state description by a system known as a parser hosted on a 68000 processor. The cure state description is then analyzed by the expert system known as the thinke hosted on another 68000 processor. The control decisions are determined using symbolic logic programmed as a rule-based paradigm generated from a human expert on the cure process. Once made, these control decisions are then posted to a blackboard hosted on an 80286 processor for execution by the autoclave feedback controller.

Abstract: A method for the regulation of the process conditions in a moulding tool which is intended for the production of products of natural or synthetic polymers. The moulding tool is made up of one or more moulding parts made of sintered metal with communicating pores obtained by pressing at a high pressure and sintering at a high temperature of a powdered material. The moulding part or parts have a moulding cavity, such that the pores are open toward the moulding cavity. The outer envelop surface of the moulding tool is tightened against leakage. The method includes filling the communicating pores with a liquid with a high vaporizing temperature and regulating the pressure on the liquid in the pores by means of a suitable pressure producer connected with the communicating pores in the moulding tool.

Abstract: An apparatus for making a plastic injection molded part with a smooth surface or skin and a hollow core wherein thermoplastic material is injected as a molten stream into the mold cavity through a sprue bushing fixed in the mold. Simultaneously, an unmeasured quantity of inert gas is introduced through an adapter into the molten stream at the sprue bushing substantially coaxially with the melt stream and at a pressure sufficient to penetrate the thermoplastic material to form a gas cavity in the molten material in the mold. For retrofitting an existing mold, an adapter can be added to the existing sprue bushing. During plastic injection and cooling in the mold the gas is maintained at a high pressure, preset, constant and adequate to maintain the plastic against the mold surface until it is self-supporting. The gas is exhausted from the mold, back through the sprue bushing and adapter, before the mold is opened.

Abstract: A vacuum system for a vacuum sizing tank utilizing electronic controls to maintain the proper negative pressure within the tank. A transducer measures the tank's vacuum. An electronic circuit compares the measured value with the preset value. Any discrepancy between the two undergoes resolution by varying the voltage applied to the variable-speed d.c. controlled vacuum pump. The resulting changes in the motor's speed brings the tank's vacuum to the desired magnitude. The continuous measurement of the vacuum and its feedback to the speed of the vacuum pump results in the maintenance of the desired vacuum within the sizing tank.

Abstract: An injection molding machine utilizing brushless DC motors in its servomechanism drive systems. Brushless DC motors provide a cost effective high power drive system which has the simplicity of control of brush-type DC motors. By utilizing higher resolution encoders and controlling pressure with the servomotor velocity control loop, motor cogging and zero velocity oscillatiions are minimized.

Abstract: A method of producing a skin-covered foamed plastic article, which includes preparing a lower mold which has a cavity formed therein; putting a bag-shaped outer skin member into the cavity, the skin member having a porous inner layer; pouring a foamable material for the foamed plastic article into the bag-shaped outer skin member; and adjusting a pressure which is created in the cavity due to foaming of the foamable material.

Abstract: A method of producing a skin-covered foamed plastic article, which includes preparing a lower mold which has a cavity formed therein; putting a bag-shaped outer skin member into the cavity, the skin member having a porous inner layer; pouring a foamable material for the foamed plastic article into the bag-shaped outer skin member; and controlling a pressure in the cavity in such a manner that the inner layer becomes saturated to a predetermined degree during curing of the material.

Abstract: A process for producing a foamable thermoplastic resin article having a relatively thin non-foamed outer shell with a smooth surface and a foamed core portion, which has excellent dimensional stability, by pressurizing a mold cavity under a pressure of gas less than the foaming pressure and not less than the surface smoothing pressure of the foamable resin and permitting the pressure of the gas simultaneously with completion of the injection to be communicated to an atmospheric pressure or lower.

Abstract: A motor control device for an electric injection molding machine. The injection molding machine has a screw rotating mechanism including a rotary shaft associated with one end of a resin feeding screw received in a heating cylinder, a holding member rotatably holding said rotary shaft and slidable in the axial direction of said rotary shaft, and a first motor for driving said screw through said rotary shaft. The injection molding machine also includes a second motor for producing a force for advancing said screw in the injecting direction and retracting said screw, a screw shaft and a nut for converting the output torque of said second motor into linear movement, and a sliding member to which said nut is fixed. The motor control device includes a load detecting member fixed at one end to said holding member and at the other end to said sliding member, and a controller for controlling the operation of the first and second motors in accordance with the level of load detected by the load detecting member.

Abstract: Method for controlling the processing and output feeding of plastic melt by extrusion, by means of an extrusion plant including a process unit (1) for processing the plastic material, a pump (3) for feeding the plastic melt to a die (4) or the like, and a screen pack assembly positioned between the process unit (1) and the pump (3). In the process unit (1) the melt is imparted a constant level of kinetics of extrusion, and the plastic melt pressure (P2) between the screen pack assembly (2) and the pump (3) is kept above a predetermined level. As a measure of the level of kinetics of extrusion, the pressure (P1) of the melt between the process unit (1) and the screen pack assembly (2), is used, preferably in combination with the melt pressure (P2) after the screen pack assembly (2).

Abstract: A control apparatus for an injection molding machine injects a melted resin within a housing into a cavity of a mold through a nozzle section of a nozzle at a housing and by movement of a screw. A nozzle opening changing mechanism variably changes a throttled path area of the nozzle while a mold temperature sensing mechanism sensing the temperature of the mold. A control mechanism controls the nozzle opening changing mechanism in accordance with the sensed temperature of the mold temperature sensing mechanism.

Abstract: A method for making a steel/concrete tank is provided. A steel interior tank is pressurized during or after pouring of a concrete outer tank around a steel inner tank. Pressurization is commenced before the concrete has set, and is maintained until substantial setting of the concrete. The resulting structure is less susceptible than previous structures to cracking of the exterior concrete upon pressure-testing of the structure for leaks.

Abstract: Apparatus for manufacturing a multicolored aerated confection product utilizing individually adjustable multi-orifice extrusion systems.

Abstract: A method of molding a skin-covered foamed plastic article, which includes by steps putting a bag-shaped outer skin member into a cavity of a lower mold, the skin member including an outer layer and a porous inner layer lined on the outer layer; putting a first upper mold on said lower mold to close the cavity; fastening the lower and first upper molds together with a first fastening force; pouring a foamable plastic material into the bag-shaped outer skin member in the cavity and curing the same; removing the first upper mold from the lower mold after the material is hardened to a certain degree; putting a second upper mold on the lower mold to define a given space therebetween; fastening the lower and second upper molds together with a second fastening force which is greater than the first fastening force; and pouring the foamable plastic material into the given space and curing the same.

Abstract: Control apparatus for an injection molding machine having a sensor provided for the injection molding machine for producing a signal representing the quality of the molded product or a molding condition of the injection molding machine, a set value memory device in which a permissible range of the signal is set, a judging member for judging as to whether the signal lies in the permissible range, a production lot data memory device containing control data for the injection molding machine with respect to a lot now being produced, and a destination table showing a destination of the data corresponding to a result of judgment of the judging member, a controller for controlling the injection molding machine in accordance with the control data stored in the production lot memory device, and another memory device for storing a plurality of sets of the production lot data regarding various lots or production conditions, and a storing device for determining a destination of the production lot data based on the result

Abstract: A method and associated apparatus for the injection molding of plastic articles of enhanced surface quality using fluid pressure. The method involves the initial step of injecting molten plastic at a nominal injection pressure from an injection molding machine through a flow path to a mold cavity defining the shape of the molded article. A charge of fluid pressurized at a predetermined level no greater than the nominal plastic injection pressure is communicated to the plastic flow path through an orifice of sufficiently small dimension to resist entry of the molten plastic against the pressure of the fluid charge. The pressurized charge of fluid responds to a reduction of the pressure in the plastic flow path below the predetermined level upon substantial completion of plastic injection and enters the flow path and passes into the mold cavity. The fluid is contained within the mold cavity under pressure until the article has set up, and is thereafter vented to atmosphere.

Abstract: The fleece-making apparatus includes a spinning nozzle system, a cooling shaft, a stretching aperture, a diffuser shaft, a fleece delivery conveyor and a device for feeding process air and for drawing outflowing air through the fleece delivery conveyor. The process air is divided into two partial flows as it is fed into the cooling shaft on each side of the cooling shaft. The upper partial flow serves for intensive cooling, the lower partial flow for additional cooling. Both partial flows are united in the cooling shaft. The cross section of the united process air flow is constricted by air control flaps positioned wedge like on opposite sides at the entrance of the stretching aperture. The process air flow issuing from the stretching aperture is influenced by pivoting wings movable about a horizontal axis at the entrance to the diffuser shaft on both sides and also by an adjustable damper which is located either above and/or below the fleece delivery conveyor.

Abstract: An injection molding machine of the present invention has a flow rate control device (11) located between an injection screw (2) mounted inside a housing (1) so that it may be rotated freely and reciprocated freely and an injection nozzle (12) mounted in the leading end of the housing (1) so as to inject the molten resin into a cavity (14) of a mold (13). The control device serves to control the rate of flow of the molten resin from the injection screw (2) to the injection nozzle (12). The flow rate control device (11) cooperates with an injection speed control device and a dwell pressure control device installed separately to control the flow rate and speed of the molten resin thereby making it possible to control the injection speed rapidly, and with a high accuracy and with an excellent response.

Abstract: An apparatus for cooling a tubular polymer film material which is being extruded, and more particularly, an apparatus for extruding tubular thermoplastic films including two tandem spaced air rings for controlling the cooling rate and production speeds of the thermoplastic films during extrusion thereof. Moreover, there is also disclosed a method for the cooling of an extruded tubular thermoplastic film material through the utilization of a tandem air ring cooling structure.

Abstract: A lever pivoted at a support point receives force from pressure receiving members located at two positions along the direction of flow of resin in a flow passage without a metal mold. A physical property or condition of the resin flowed into the metal mold is determined as a function of the time during which the resin flows between the two pressure receiving members and of a difference pressure acting on the lever at the two positions.

Abstract: Apparatus for extruding a pliable, thin-walled tube comprising an extrusion and shaping die assembly comprising an annular die body, a mandrel supported within the annular die body, a mandrel extension mounted on the mandrel adjacent the die outlet, the mandrel extension having a diameter less than the diameter of the mandrel, a sizing disk supported by the mandrel extension, and a source capable of supplying molten polymeric material to the die assembly under pressure to force the material through an annular extrusion flow channel around the mandrel and out the die outlet thereby forming a moving tube of the material, the mandrel extension extending outwardly from the die in the direction in which the tube is extruded, the annular die body having at least one fluid passageway to channel fluid introduced under pressure into the annular die body axially through the mandrel and outwardly from the axis of the mandrel extension to form an air pillow adapted to cool and support the tube around and spaced from the

Abstract: Disclosed herewith is an injection control apparatus which is used for an injection-molding machine that is subjected to injection and hold pressure controls by means of a numerical control unit (30), and which controls the switching from the injection control to the hold pressure control based on the injection time and resin pressure so as to improve the operation reliability of the injection-molding machine and ensures production of good-quality molded articles.When the pressure on the resin filled in a mold that is detected by pressure detection means (26) exceeds preset pressure or when a predetermined time elapses after the start of the injection operation, hold pressure control means (30, 50, 60) starts the hold pressure control. When pulse distribution to a hold end position is not completed upon completion of the hold pressure control, an error register (51) of a servo circuit (50) is followed up by follow-up means (30) so that the pulse distribution is forcibly executed.

Abstract: An injection molding machine is provided which uses servo motors (M1, M2) as driving sources and in which a preset back pressure is correctly transmitted to a resin. The torque limit values and rotating directions of an injection servo motor in respective stages is set in accordance with the relationship in magnitude between the preset back pressure and the resistance during a transmission mechanism of the respective stages of metering. A servo circuit of an injection servo motor is torque-limited with a preset torque limit value, and the injection servo motor is driven in a preset rotating direction.

Abstract: This invention relates to a method and apparatus for improving not only the quality of the production of molded foamable thermoplastic resin particles converted into fusion-bonded materials but also the output by protecting the resin from atmospheric pressure by pressurizing the particles and heating the particles to soften the same.

Abstract: The process for making the spun fleece proceeds in a filament-spinning unit having a spinning nozzle system, a cooling shaft, a stretching aperture, a diffuser shaft, a continuously moving fleece recovery conveyor and a device for feeding process air and for drawing outflowing air through the fleece recovery conveyor. The cooling shaft has a shaft wall provided with a plurality of air orifices. That allows process air required for cooling to be fed into the cooling shaft. That air flow at least partially is drawn through the fleece recovery conveyor. The thickness of the spun fleece is measured on the fleece recovery conveyor in the transport direction downstream of the diffuser shaft. The measured value is compared with a predetermined set value. On deviation of the measured value from the set value the setting angle of the air control flap or flaps which are located adjacent the entrance of the stretching aperture is changed.

Abstract: A method of molding pre-foamed synthetic resin particles is described, which comprises increasing the pressure in a mold cavity with a pressurized gas, charging the mold cavity with pre-foamed synthetic resin particles as they are compressed with a gas pressurized to a pressure higher than the pressure in the mold cavity and heating the charged pre-foamed synthetic resin particles with steam so that they are fused together or expanded and fused together to form a foamed molded article, wherein a pressure detector is provided in a conduit for conveying the pre-foamed synthetic resin particles into the mold cavity as they are carried by the pressurized gas or at an inlet portion of a charging port leading to the mold cavity, and the supply of pre-foamed synthetic resin particles into the mold cavity is stopped when the pressure detected by the detector exceeds the pressure in the mold cavity by a predetermined amount.

Abstract: Disclosed is a control method in which control errors, attributable to a change of the state of a transmission mechanism, disposed between a servomotor and a load driven thereby, are reduced in controlling a driving force to be applied to the load.A detected value (PH) of the driving force applied actually to the load is compared with a set value (PL') of the force to be applied to the load. The driving current of the servomotor is controlled in accordance with the result of such comparison. Thereupon, a change of the correlation between the servomotor output and the driving force applied actually to the load, which is attributable to the change of the state of the transmission mechanism, is compensated automatically. Thus, the driving force applied actually to the load is adjusted accurately to the set value.

Abstract: An aromatic polyester showing anisotropy in the molten state is melt spun stably for a long period of time by controlling an extrusion pressure at a nozzle portion to 3 kg/cm.sup.2 G or higher and an atmospheric temperature T.sub.N at a nozzle outlet to a degree satisfying the following formula: (T.sub.F -100).ltoreq.T.sub.N .ltoreq.T.sub.F, wherein T.sub.F is a flowing temperature of the aromatic polyester, and preferably controlling the pressure of a polymer melt at a tip outlet of an extruder to 15 kg/cm.sup.2 G or higher, whereby a highly orientated fiber of fine denier is obtained.

Abstract: A dwell control system of an injection molding machine is adapted to drive an injection shaft by an electric motor (20) and to control the electric motor (20) by a numerical control unit (30). At the time of a dwell operation, the numerical control unit (30) operates the electric motor (20) under the application of a torque limit to apply a predetermined pressure to a molten material in a mold (4).

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.