Abstract: The extrusion blow molding of hollow bodies is carried out with a wall thickness program which in addition to varying the gap width over the entire perimeter of the gap in accordance with a first program curve and varying the geometry of the gap in response to a second program curve, automatically enhances a profiling of the preform to increase differences between the thick and thin regions with the variation in geometry when the gap width is greater in a reference value and diminishes the profiling of the preform to decrease such differences when the gap width is less than the reference value.

Abstract: The present invention is a hollow article with an integral impact absorbing rib and the method of manufacturing the same. The apparatus is a hollow article made of thermoplastic resin and integrally formed by blow molding, comprising a first wall and a second wall confronting across a spacing. There is an integral rib between the first wall and the second wall, wherein the integral rib comprises a flat rib between the walls and one or more hollow ribs adjacent to each of two side ends of the flat rib. The impact absorbing rib is disposed at intervals and in an impact action direction. The rib is uniform in shape, dimensions and wall width, and free from reduction of wall width of the inner rib, yet possessing proper structural support and mechanical strength, and excellent in impact absorbing performance.

Abstract: Process for manufacturing hollow plastic bodies, especially motor-vehicle fuel tanks, from an extruded parison of closed cross section, in which at least one cut is made in the parison which is then formed by molding.

Abstract: A plastic hollow preform is drawn through a mold passage formed in a closed mold by applying a generally constant suction to a downstream end of a conduit having an upstream end connected to an output end of the mold passage. A flow cross section of the conduit is varied between its upstream and downstream ends so as to vary a rate at which the preform is drawn through the passage by the suction. The flow cross section is varied by displacing a valve element in the conduit between positions in which it differently blocks flow through the conduit.

Abstract: A blow molded article comprises a hollow body having a substantially enclosed hollow space therein, the hollow space accommodating a reinforcement for structurally reinforcing a strength of the blow molded article, with the reinforcement being tightly attached and fixed to at least a part of an internal wall defining the hollow space. A molding machine for this blow molded article comprises a pair of mold halves which can freely move to and away from each other in horizontal directions, and a parison feeder for supplying a parison downwardly between the mold halves. The parison feeder is arranged to supply a bottomless parison. Below the mold halves, the molding machine is provided with a support device which holds a reinforcement such that the reinforcement is positioned inside a hollow space in the blow molded article, and also provided with elevating means for freely raising and lowering the support device.

Abstract: A process for blow-molding hollow bodies from thermoplastic synthetic resin wherein, in addition to control to accurately position an extruder thermoplastic melt preform in the blow mold and to maintain a constant weight of the extruded preform, on the program curve which itself is a superimposition of the profile curve of the preform and a base gap determined in accordance with the nozzle gap width through which the preform is extruded, there is superimposed a correction strip which can be varied depending upon material distribution changes as a result, for example, of sag of the preform.

Abstract: A molding machine for producing plastic hollow bodies and including at least one extrusion die, an injection plunger element for delivering plasticized plastic material to the at least one extrusion die, two blow mold halves arranged between the extrusion die and triggering device and displaceable toward each other for forming a blow mold in which the preform produced by the extrusion die is received and a hollow body is formed, a computerized control system for controlling parameters of the produced hollow bodies, a pressure-measuring device for determining pressure of the plasticized plastic material delivered to the injection die, weight and height measuring devices for determining weight and height of the produced hollow bodies, data-transmitting and control lines connecting the control system with the measuring devices, and a transfer gripping device for transferring hollow bodies from the blow mold station to the weight and height measuring devices.

Abstract: A blow-molding apparatus has an ionization bar extending along the row of extruded parisons to dissipate electrostatic charge thereon. The ionization bar comprises a conductive strip received in an insulating holder and preferably a copper laminate strip whose longitudinal edge is turned toward the parisons and can be formed with an array of pointed teeth.

Abstract: A cross head mounted at an end portion of an extruder for extruding a parison between a pair of elements of a metallic mold and a filling nozzle lifting apparatus having a filling nozzle are provided in parallel, and opening and closing of the metallic mold by a mold clamping apparatus, back and forth movement of the mold clamping apparatus between a parison receiving position and a filling position by a metallic mold feeding apparatus, upward and downward movement of the filling nozzle and back and forth movement of a parison cutter of a parison cutting apparatus are electrically operated. Further, a metallic mold body of the metallic mold is formed from a ventilation material, through which air in the metallic mold is sucked by vacuum to expand the parison. Furthermore, a clean air box is constructed so that it can accommodate the filling nozzle, and clean air is jetted from a jetting hole provided in a lower wall of the clean air box so that a clean air atmosphere may be provided above the metallic mold.

Abstract: Provided is a swing-driving device for driving two low molding units so as to swing around corresponding swinging fulcrums, each of the blow molding units having a carriage, one end portion of which is supported by the swinging fulcrum so as to swing, and a blow molding mold disposed on the carriage. The blow molding mold of one blow molding unit receives a parison on a common receiving position and is made to be an mold close state. The blow molding mold swings around a swinging fulcrum, and moves from the receiving position to a shunting position via a detaching position. Thereafter, the blow molding mold returns to the detaching position and is made to be a mold open state. A hollow article formed by blow-molding the parison in the blow molding mold is take out and moved to the receiving position kept in the mold open state.

Abstract: An in-mold labeling system for use with a rotary blow molding machine (10) includes first and second electrical servomotors (46, 64) and first and second cam mechanisms (48, 66) respectively driven by the servomotors to move a dispensing head (36) between supply and delivery locations and to move a label carrier (38) on the dispensing head between retracted and label transfer positions independently of each other. A sensor (92) of the system senses rotation of a rotary wheel (12) of the machine to operate first and second electrical controllers (84,86) that respectively operate the first and second electrical servomotors (46,64) in coordination with the machine operation but independently of each other.

Abstract: A method for cascade, closed loop control of multiple operating parameters for an extrusion blow molding machine having multiple accumulators is disclosed. The method provides closed loop control of the ram back pressure during refill, along with the closed loop adjustment of the pressure set points for “slave” accumulators based on a comparison of ram positions with that of a “master” accumulator. For systems that supply each accumulator with a separate extruder, the rotational speed of the extruder screw is the controlled operating parameter during refill. With respect to extrusion of the parisons, there is closed loop control of the ram velocity in conjunction with adjustment of the velocity set points for the slave accumulators based on a comparison of ram positions with that of the master accumulator.

Abstract: The invention relates to a system for preforming an extruded plastics parison including a nonplanar conveyor belt. It also relates to a method for preforming an extruded parison, including a step during which the parison is deposited on a conveyor belt. The conveyor belt is not planar. This step may be accompanied by a step in which the parison undergoes transverse deformation. The invention also relates to a method of manufacturing at least one article, including such a preforming step.

Abstract: The accumulator of an extrusion blow molding machine is constructed to include a stroke positioner that comprises inter-engaging, threaded components that enable the piston of the programming cylinder to be adjusted relative to the inner rod of the programming system in the accumulator assembly. Since the inner rod ultimately connects to the die pin, this adjustment directly determines the position at which the piston in the programming cylinder will close off the die gap. In particular, the components of the programming system can be adjusted so that the die gap is closed just as the piston of the programming cylinder reaches the limit of its stroke.

Abstract: The present invention relates to a multi-stage, post-mold cooling method and apparatus used in conjunction with an injection molding machine having an aggressive cycle time and a high output. The apparatus of the present invention includes a thermal conditioning device/station with cooling tubes for keeping separate the preforms of each batch and effecting cooling of the molded preforms, several separated cooling levels for simultaneously cooling multiple batches of preforms, and internal devices for automatically transferring each batch of molded preforms from one cooling level to the next. In a preferred embodiment, the thermal aconditioning device/station is partially sealed to create a controlled temperature environment for conditioning the molded articles. In another embodiment, the thermal conditioning device/station includes a level for re-heating the preforms.

Abstract: In a process and apparatus for producing elongate curved hollow bodies at least partially comprising thermoplastic material a preform is extruded from an extrusion system head and engaged by a gripping means. The preform is moved by the gripping means into the region of a guide stencil disposed above the mold cavity of a mold portion of a divided blow molding mold and introduced into the mold cavity by a simultaneous downward movement of the gripping means and a movement following the configuration of the guide stencil. The guide stencil has two mutually opposite walls, the spacing of which increases in an upward direction and the spacing of which at the bottom of the guide stencil approximately corresponds to the maximum width of the mold cavity. The preform is thus guided towards the mold cavity by the walls, acquiring its definitive orientation with respect thereto by virtue of such guidance, passing through a lower opening in the guide stencil into the mold cavity.

Abstract: An accumulator-type blow molding machine includes hydraulic cylinders for closing mold parts on platens and a control system for valves flowing hydraulic fluid to the cylinders. The control system calculates the desired position of one platen from the measured position of the other platen and generates work output signals accordingly.

Abstract: A blow molding machine comprising a base, a wheel mounted rotationally on the base, a controller to control operation of a pin within a die, and a position detector for detecting a short run mold on the wheel wherein the wheel comprises a plurality of identical molds and the short run mold which differs in size and/or shape from each of the plurality of identical molds. The position detector, upon detecting the short run mold, switches a relay to switch from a first pin control program causing the extrusion of a parison having appropriate parameters for the plurality of identical molds, to a second pin control program causing the extrusion of a parison having appropriate parameters for the short run mold.

Abstract: A method of manufacturing hollow bodies including inserting into spaced mold halves of a blow mold of a blow molding machine plastic hose-shaped blanks at an extrusion station of the blow molding machine and closing the blow mold, displacing the closed blow mold from the extrusion station to a calibration station of the blow molding machine, inserting thereat blow mandrels into respective cavities of the closed blow mold, lifting, after expiration of predetermined blow time, the blow mandrels, together with the blown hollow bodies to an intermediate position and removing the blown hollow bodies from the blow mandrels lifting the blow mandrels to their initial position thereof, and displacing the blow mold from the calibration station to the extrusion station, with the displacing of the blow mold between the extrusion station and the calibration station being effected by displacing the blow mold at a right angle to a connection line of arranged side-by-side cavities of the blow mold.

Abstract: A universal mold carrier for use in a mold assembly compensates for parting forces associated with container formation by directing a compensating air flow pressure to the rear surface of the mold carrier. The mold carrier includes two mold halves adapted to matingly engage each other and hold within the mold carriers interchangeable mold shells. One of the mold carriers has an outside wall that has a plurality of independent air flow compensating surface areas located thereon. This mold carrier further has an air flow communication line interconnecting the independent air flow compensating surface areas. Shut off valves are located in the one carrier to close and to open the air flow communication line between adjacent independent air flow compensating surface areas to allow for adjustment of the compensating pressure.

Abstract: A process and an apparatus for molding, in which a molten thermoplastic resin is firmly fitted onto a molding surface of a mold under a pressure lower than or equal to 100 kg/cm.sup.2 and is cured to obtain a molded product. The molding apparatus has a mold main body, and a mold body on which the molding surface is defined. The mold body is supported relative to the mold main body with maintaining a space on the back side of the molding surface in a heat insulative manner by a supporting member which includes at least a heat insulative supporting member having a thermal conductivity of 0.001 to 1 Kcal/mh .degree.C. and a longitudinal elastic modulus of 0.01 to 10 kg/cm.sup.2. In the space, a heating fluid for heating the molding surface from the bask side to a temperature higher than or equal to Vicat softening temperate (T) .degree.C.

Abstract: A method and devices for coating a carrier part make it possible to coat the carrier part formed of a less expensive material with a higher-quality and thus more-expensive material in only a defined region. As a result, novel properties attainable by the coating, such as improving hardness or resistance or varying color or appearance, finally exist only in the region where it is actually needed. Therefore, the coating material is fed in through one or more associated feeding devices, below a distributor head, in a preliminary tube that is already provided with the carrier material, in one or more angular regions relative to the horizontal axis of the preliminary tube. At least one distributor element that has adjustable segments is disposed below the rotatably disposed distributor head. The segments are provided with profiled sections for providing different wall thicknesses.

Abstract: The apparatus has means (10, 11) for placing a parison (12) between two portions of a blow mold (14, 16). The parison (12) is put on the head of a blowpipe (32) placed between the two mold portions. On closing the mold, the top end of the parison is pinched in a top region of the mold and the bottom end of the parison is clamped against the blowpipe (32). A pre-blow step is performed on the parison to obtain an envelope which is then turned over by moving the blowpipe (32) upwards together with a turnover piston (34, 36), prior to performing a final blow step.

Abstract: An accumulator-type blow molding machine includes hydraulic cylinders for closing mold parts on platens and control systems for valves flowing hydraulic fluid to the cylinders. The control systems generate work output signals for the valves according to the operational parameters of the valves, the hydraulic systems and the bearings supporting the platens.

Abstract: A process and an apparatus for molding, in which a molten thermoplastic resin is firmly fitted onto a molding surface of a mold under a pressure lower than or equal to 100 kg/cm.sup.2 and is cured to obtain a molded product. The molding apparatus has a mold main body, and a mold body on which the molding surface is defined. The mold body is supported relative to the mold main body with maintaining a space on the back side of the molding surface in a heat insulative manner by a supporting member which includes at least a heat insulative supporting member having a thermal conductivity of 0.001 to 1 Kcal/mh .degree.C. and a longitudinal elastic modulus of 0.01 to 10 kg/cm.sup.2. In the space, a heating fluid for heating the molding surface from the bask side to a temperature higher than or equal to Vicat softening temperate (T) .degree.C.

Abstract: A flat blow molding machine adapted to extrude flat hollow parison from clearance between a flat core and a flat die surrounding the core, characterized in that both ends of the die are slidable in a width direction with respect to a center, the core is replaceable in accordance with expansion and contraction of the die in the width direction. According to this construction, it is possible to change the width of the flat hollow parison extruded from the clearance between the core and the die by sliding the both ends of the die in the width direction and replacing the core upon expansion and contraction of the core in the width direction. Further, if the flat core is constructed from a planar replaceable portion and curved (three dimensional) non-replaceable portions and only the planar replaceable portion is exchanged upon replacement, preparing a plurality of inexpensive-to-manufacture planar replaceable portions having different lengths is enough and the cost is reduced.

Abstract: An extrusion head for a blow-molding apparatus has an annular and relatively rigid outer housing centered on a housing axis, a rigid ring axially fixed in the housing and shiftable radially of the housing axis in the housing, and a sleeve generally coaxially received in the housing and having an upstream end secured to the ring and a downstream end radially elastically deflectable transversely of the housing axis relative to the upstream end. A rigid core coaxially received within the sleeve in the housing has an outer surface defining an annular passage with an inner surface of the sleeve.

Abstract: A method and apparatus wherein an extruder provides extruded plastic parisons to a first and second horizontally movable blow mold assemblies, and each blow mold assembly includes two sets of blow molds, and each set includes a pair of blow mold halves. The blow mold halves are closed about the tubular parisons and moved to one of two blow molding stations where a blow pin at the blow molding station blows the parison to form a hollow blow molded article. More specifically, four platens are provided in each blow mold assembly. A first pair of outer and inner platens supports the first pair of blow mold halves and a second pair of outer and inner platens supports the second pair of blow mold halves. A pair of tie rods passes through all four platens. The first outer platen is attached to the ends of the tie rods. The second outer platen is moved by a mechanism such as a cylinder or toggle mechanism for movement on the tie rods.

Abstract: The present invention relates to a method for producing a blow-molded tubular body having multiple dimensions with the following stages:a) extrusion of a tubular component that is closed at the front, with injection of gas inside the tubular component (10), and engagement of the tubular component with a shaping unit (12, 13),b) deposition of the shaped tubular component, in the plastic state, on a high-level half-mold part (15),c) free descent of a part of the tubular component onto a low-level half-mold part (18), located at a level that is lower than that of the high-level half-mold part (15),d) closure of the half-mold and blow-molding.

Abstract: A cross head mounted at an end portion of an extruder for extruding a parison between a pair of elements of a metallic mold and a filling nozzle lifting apparatus having a filling nozzle are provided in parallel, and opening and closing of the metallic mold by a mold clamping apparatus, back and forth movement of the mold clamping apparatus between a parison receiving position and a filling position by a metallic mold feeding apparatus, upward and downward movement of the filling nozzle and back and forth movement of a parison cutter of a parison cutting apparatus are electrically operated. Further, a metallic mold body of the metallic mold is formed from a ventilation material, through which air in the metallic mold is sucked by vacuum to expand the parison. Furthermore, a clean air box is constructed so that it can accommodate the filling nozzle, and clean air is jetted from a jetting hole provided in a lower wall of the clean air box so that a clean air atmosphere may be provided above the metallic mold.

Abstract: In a method of blow moulding, a parison is extruded by pushing a hollow tube of hot thermoplastic material through a die gap 2 between a mandrel 3 and die 1. An exit compression ring 5 is formed on the mandrel 3 adjacent to the die exit 2. The ring acts as a flow enhancer to ensure free flow of the thermoplastic material. Outer surfaces of the die 1 and mandrel 3 may be provided with release strips 9, 10 to prevent the parison becoming stuck to the die face.

Abstract: A device and method is provided for manufacturing at least two curved, joined tubes. The method includes extruding, without clamping, a blank in a modifiable-geometry mold cavity and placing the blank in the cavity by means of an entraining air stream, and then modifying the geometry of the mold cavity to clamp the blank and injecting a gas to shape the blank to the mold cavity geometry thus modified to obtain at least two curved, joined tubes. The device includes a mold cavity and at least one moving part for modifying a geometry of the mold cavity. The moving part is displaceable between a retracted position in which a blank can be placed in the mold cavity under the action of an air stream and a blank clamping position to allow formation of at least two curved, joined tubes upon blowing.

Abstract: In a blow-molding system in which a parison programmer is coupled to orifice tooling in an extrusion die head for controlling wall thickness of an extruded parison fed to a blow-molding apparatus, a method of synchronizing operation of the parison programmer contemplates placement of observable indicia on the parison after the parison exits the die head. This indicia placement preferably is carried out under control of the parison programmer to place the indicia at a predetermined position along the parison profile, such that mis-positioning of the indicia indicates absence of phase synchronization of the parison programmer. The indicia is then observed on a molded article to determine phasing of the parison programmer relative to the molding apparatus, and operation of the parison programmer is adjusted to correct any mis-positioning.

Abstract: An air cushion having smooth exterior surfaces is produced by extruding a material film defined by upper and lower surfaces secured together by a plurality of spaced ribs. The film is clamped between a shaping mold and a needle having a plurality of air holes corresponding to cells defined by the ribs is inserted through the film and a fluid is blown into the cells to form the air cushion.

Abstract: An accumulator head is convertible to alternate capacity ranges by providing a construction that has a segmented barrel with a matching ram in the purging system. More specifically, the accumulator barrel is divided into upper and lower segments so that the accumulator chamber is bounded by the lower barrel segment. The inner diameter of the lower barrel segment matches the outer diameter of the ram, and the length of the lower barrel segment corresponds roughly to the range of movement of the ram. With this accumulator construction, it is possible to change the working volume of the internal accumulator chamber by simply changing two parts, i.e., the lower barrel segment (inner diameter) and the ram (outer diameter). In addition, the two piece accumulator barrel design facilitates a more economical construction since the lower segment (where most of the wear occurs) can be made of a wear resistant grade of steel, while the upper segment can be manufactured from a lower cost, more easily machined material.

Abstract: In the manufacture of composite paperboard/polymer packages, the adhesion between the polymer component and paperboard component can be enhanced by treating the polymer film with a surface treatment, for example, ozone, before the two components are brought together. The present invention is particularly applicable to a blow molding process employing one or more paperboard blanks and a blow molded polymer film.

Abstract: A valve pin (4) for controlling an injection amount of molten resin is inserted into a cavity (13), and then the molten resin is injected by way of a gate (10) along the surface of the valve pin (4) into the cavity (13) to be dropped therein, and tip ends of this dropping molten resin merges at a bottom (13a) of the cavity (13) to form a hollow portion (S) between the valve pin (4) and the dropped molten resin. Then, air is blown into the hollow portion (S) from the tip end of the valve pin (4), inflates the hollow portion (S), brings it into contact with the inner surface of the cavity (13), and cools and solidifies this molten resin, so as to attain a hollow molded product (40).

Abstract: An electric drive for controlling the die gap in a continuous blow molding head and the die gap and pushout in an accumulator blow molding head. The electric drive includes a programming screw for attachment to a programming rod for setting the die gap, a programming nut and an electric motor for rotating the programming nut. In an accumulator blow molding head, the electric drive further includes a shooting screw for attachment to a shooting rod for controlling pushout, a shooting nut and an electric motor for rotating the shooting nut. The programming screw and the shooting screw are coaxial with the programming rod passing through the shooting screw.

Abstract: A rotary blow molding machine includes a horizontal main shaft with a plurality of molds spaced around the shaft and mounted on the shaft by linear bearings for movement along the shaft. A shaft drive rotates the shaft and molds around the axis of the shaft in the steps and dwells the shaft and molds between steps. Open molds are rotated from a lower container eject position up to a parison capture position and then close on a parison. The closed molds are shifted axially along the main shaft and the parison is blown. Further rotation of the shaft returns the molds to the mold eject position where the molds open and molded containers are ejected downwardly with gravity assist.

Abstract: A process for blow-molding hollow bodies from thermoplastic synthetic resin wherein, in addition to control to accurately position an extruder thermoplastic melt preform in the blow mold and to maintain a constant weight of the extruded preform, on the program curve which itself is a superimposition of the profile curve of the preform and a base gap determined in accordance with the nozzle gap width through which the preform is extruded, there is superimposed a correction strip which can be varied depending upon material distribution changes as a result, for example, of sag of the preform.

Abstract: A parison transporting device includes a conveyor system moveable either in longitudinal or transverse fashion relative to the direction of parison discharge in the tube receiving position below the tube forming head to receive, on the conveyor system, either a straight tubular piece or a tubular piece curved in accordance with the mold cavity of the blow mold. The conveyor system is then moved to the blow mold and into a position where an end section of the conveyor belt is positioned vertically above an end section of the mold cavity with the tubular piece located thereon. A rotating conveyor belt carried by the conveyor system is moved above the mold cavity either in both horizontal directions (X-direction and Y-direction) to arrange the straight tubular piece into the curved mold cavity, or, in the alternative, linearly above the mold cavity to drop the tubular piece, already positioned in curved fashion on the conveyor belt, into the correspondingly formed mold cavity.

Abstract: A method of manufacturing a container, wherein less material is required to produce the container, the container has a more uniform wall thickness, and malformations around the neck of the container are significantly reduced. The method includes forming plastic into a parison and blowing it into a mold having a tapered neck portion and a body portion, which join to form an annular corner for contacting the parison. A blow pin blows air into the mold and parison, causing the parison to expand and conform to the inner contour of the mold. The taper of the neck portion and the annular corner thereby formed, cool the plastic at that point and more uniformly form the parison into the container, the amount of material wasted and required in manufacturing the container is substantially reduced, as is malformations and warping which usually occur about the neck of the finished container.

Abstract: The accumulator of an extrusion blow molding machine is constructed so that the programming cylinder and die adjustment rod have axially aligned bores to receive a die pin retaining rod. The retaining rod holds the die pin in place by means of a lower split ring that nests inside the die pin and a lock nut combined with an upper split ring associated with the programming cylinder. When the lock nut is loosened and the upper split ring is removed, the retaining rod is moved down (while the die pin is held in place) and the lower split ring is removed. The die pin is then free to slide off the retaining rod and be removed from the accumulator head.

Abstract: The parison transporting device includes two opposite side wall elements whose inner surfaces facing each other are curved in accordance with the mold cavity of the blow mold. Rods which in the longitudinal direction of the parison transporting device are mounted in offset relationship in alternate fashion and form the bottom of the parison transporting device are secured to the side wall elements. The side wall elements are movable towards and away from each other. In the tube receiving position, the side wall elements are spaced apart from each other to such a degree that a parison tube can be placed in straight fashion between the side wall elements. The side wall elements are subsequently moved towards each other up to a distance corresponding to the thickness of the parison tube, whereby the parison tube is exactly shaped in the form of the mold cavity of the blow mold. The side wall elements are moved apart above the blow mold to such an extent that the parison tube drops into the mold cavity.

Abstract: A rod 3 is driven forward to open an annular slit 5 between a die 2 and a mandrel 4 and the molten resin in a resin accumulation chamber 10 is expelled from annular slit 5 to form a parison. In this operation, the die 2 is displaced from an original position adjoining to the mandrel 4 (axially aligned position) upon opening of the annular slit 5 to correct for any variation in thickness of parison P to be extruded from the annular slit 5. Then, the molten resin accumulated in accumulation chamber 10 is expelled from annular slit 5 to form parison P. The die 2 is then reset to the original position to bring the die 2 and mandrel 4 into axial alignment. Therefore, as the rod 3 is driven back, the annular slit 5 can be closed tight by the mandrel 4 to prevent resin leakage. After closure of the annular slit 5, molten resin is accumulated again in the accumulation chamber 10 and the annular slit 5 is opened. This procedure is repeated to produce parisons on an intermittent basis.

Abstract: A parison extrusion head includes a cylindrical body, a programing rod in the body, a die pin on the end of the rod, and a die ring mounted on the end of the body by a clamp assembly having a pair of clamp arms which are connected to the body by hinges and are rotated between a closed position holding the die ring on the body an open position permitting free removal of the die ring. The clamp arms carry bolts used to move the die ring laterally and adjust the thickness of the extruded parison.

Abstract: An apparatus for forming a thermoplastic pipe having a profiled surface includes a nozzle having an extrusion orifice feeding extrudate in a downstream direction to a mold path which extends from the nozzle and along which are provided a first mold block and a second mold block downstream of the first mold block. The mold blocks are closable around the extrudate to form the pipe and are openable to release the pipe. The mold blocks are moved together with one another and with the pipe in the downstream direction when the mold blocks are closed and are opened and sequentially moved in an upstream direction along an axis contiguous with the axis of the mold path while the extrudate continues to move in the downstream direction. The first mold block is moved in the upstream direction before the second mold block such that the mold blocks never pass one another on the mold path.

Abstract: An apparatus for manufacturing multilayer hollow articles having sections different from one another in respect to the kinds of resins, number of layers, and thickness of layers along the circumference in the horizontal section of an article with the narrowest of the sections in any one of the resin layers extending in a specified width along the longitudinal wall of an article and being capable of satisfying the sectional performance requirements. An apparatus is provided for manufacturing multilayer hollow articles with the wall thickness ratio of resin layers in each section varying along the longitudinal wall of an article or those with the sectional width in each resin layer varying along the longitudinal wall of an article. Hollow articles molded by the apparatus of this invention are particularly useful for automotive bumpers, the seats and backs of chairs, and boiler-room doors.

Abstract: An extrusion molding apparatus includes a die head with first, second, third and fourth annular nozzles. An adhesive extruder is connected to the first and third nozzles, a barrier extruder is connected to the second nozzle and a reclaimed material extruder is connected to the fourth nozzle. Inner and outer main material flow passages are connected to a main material extruder, as well. The annular nozzles and the main material flow passages are connected to an extrusion nozzle for forming a parison. The barrier material extruder has a cylinder which is connected to the second nozzle. A screw lies within the cylinder. The second nozzle has a ridge opposite an end of the screw, for dividing the extruded barrier flow material, mitigating stagnation of the barrier material as it passes through the second nozzle. A method of forming a parison is described, as well.

Abstract: An accumulator head for a blow molding machine uses an electromechanical drive assembly for the purging and programming functions. The purging actuator of the drive assembly includes a ball screw and nut assembly in which the ball screw is rotated by an electric motor to move the ball nut assembly vertically and operate the plunger of the accumulator. A second ball screw and nut assembly is included in the programming actuator of the drive assembly for moving the mandrel vertically, thereby controlling the size of the die outlet opening of the accumulator. Preferably, the ball screws of the programming and purging actuators are axially aligned with the nut assemblies each carried by a yoke that travels on guide rods. Four support rods are provided to maintain alignment and provide stationary mounting for the respective motors. The structure has sufficient rigidity to supply the force required for the purging operation, but uses no hydraulic actuators.