Abstract: Method of manufacturing a dental aspirator by extruding a continuous tube with a bellows portion. The tube is angled to form a number of folds, each of which consists of two cup-shaped portions having concave surfaces facing each other. One cup-shaped portion is made smaller than the other, allowing them to be snapped together. The bellows are formed from the tube wall by chilled mold chains. At the same time, the tube is profiled to form an end portion at the suction end of the finished aspirator.

Abstract: A method for producing polymeric tubing which is resistant to permeation by organic material contained therein which has at least one region defined by a plurality of outwardly extending annular ridges. In this method, tubular polymeric material having a first outer diameter and composed of at least three overlying polymeric layers is introduced into a mold device upon exit of the tubular polymeric material from a suitable extrusion device, the surface of the mold device having at least one region defined by an annular depression in an essentially cylindrical surface. Once the tubular material is introduced, it is expanded to a second outer diameter such that the tubular material deformably contacts the mold surface. The corrugated tubular material then exits from the die device after completion of the expansion step.

Abstract: A travelling mold tunnel for the vacuum forming of profiled tube from extruded parison of molten thermoplastic material includes a plurality of parallel mold cavities with a vacuum applied to each of the mold cavities.

Abstract: Film-based composite structures meet the requirements of highly weight-efficient SDI space-based systems. These structures are rigid, lightweight, dimensionally stable, and possess a high degree of structural damping. Thin-walled structures (wall thickness less than 50 .mu.) made from self-reinforced ordered-polymer films overcome drawbacks of fiber-reinforced composites, and provide resistance to microcracking, ply delamination and impact. They have high temperature capability (over 300.degree. C.), low temperature (cryogenic) capability and the capability for hardening and survivability. The modulus and dimensional stability of film-based ultralightweight honeycomb sandwich structures is better than currently possible with aluminum or fiber-reinforced composite materials. Other thin-walled structures such as tension web beams and thin facesheets also show similar stiffness-to-weight advantages over current materials.

Abstract: A travelling mold tunnel for forming double walled corrugated tube has a first portion for forming corrugated tube and a second belled portion for forming a cuff portion suitable for coupling with another tube. At the upstream end of the belled portion, radial small diameter passages are provided so that a pressure differential may be set up between the inside and the outside of a first parison within the belled portion. Thus, vacuum may be applied through the radial passages to allow an inner parison to laminate with the first parison over its inner surface in the belled portion. The first parison is drawn into the passages in protruding balloons. These may be ruptured. Alternatively, positive pressure may be used. In this case, the balloons may be ruptured inwardly.

Abstract: An apparatus for the manufacture of pipes having transverse profile features has a machine bed, on which half shells, which can be combined to form a mold, are rotatably and displaceably drivable. The half shells are pressed together on a molding path by guide rails, of which one is displaceable at right angles to the direction of production by hydraulically actuatable drives. Interlockings may be provided in addition, a locking member of which engaging with an associated locking recess.

Abstract: The invention concerns apparatus for molding tube (20) utilizing a travelling mold tunnel. The tunnel is made up of mold blocks (16) each comprising parts (13, 15) which are hinged together to be closeable to form the tunnel and openable to release tube from the tunnel. The opened mold blocks (16) from the downstream end of the tunnel are opened and returned to the upstream end without change in their orientation to reform the tunnel about an extrusion nozzle (18) for thermoplastic extrudate.

Abstract: An article is provided comprising a plurality of straight spaced parallel extruded elements separated by a regularly undulated extruded element having an aspect ratio of at least about two, with undulations having opposed apexes on either side thereof, with apexes on one side of the undulated element being bonded to one of the parallel extruded elements and the apexes on the other side of the undulated element being bonded to the other of said parallel extruded elements.

Abstract: An apparatus for manufacturing from a mouldable material a pipe having ribs on its outer surface and a smooth inner surface has a core including a shaft, a conically widening mandrel located downstream of the shaft in a direction of production and a kernel having an initial zone and an end zone respectively of substantially uniform diameters successively disposed downstream of the mandrel. An extrusion sleeve surrounds the core and forms with the core a nozzle for the material. The extrusion sleeve has a first end face located upstream of the kernel. Moulds encase the extrusion sleeve and the core, the moulds being movable along endless paths and having grooves on inner surfaces for forming the ribs on the pipe. A heater heats the initial zone of the kernel, the initial zone of the kernel being cylindrical. A first cooler cools the end zone of the kernel.

Abstract: A method and apparatus for manufacturing a hose for a vacuum cleaner, such hose having anti-whistling characteristics. In a standard blow molding process, a blow pipe is configured with a plurality of printing rollers having arcuate outer surfaces configured and spaced in such a manner as to assure engagement of the entirety of the hose with a printing roller during the manufacturing process. The printing rollers are provided with apertures which, upon engagement with the tacky material of the inner surface of inwardly extending corrugations causes indentations or protrusions in such surface. The roughened interior surface prevents the formation of audible harmonics when air passes through the tube in response to a vacuum source at one end thereof.

Abstract: For the continuous manufacture of a compound pipe with a pipe socket including a smooth internal tube and an external tube provided with transverse grooves and welded together with the latter, an external tube and an internal tube are extruded, the latter into the external tube. While the normal compound pipe is manufactured, gas is blown at a slight overpressure into the space beteen the external tube and the internal tube. When the pipe socket is produced, this space is vented so that a full-surface bearing of the internal tube against the external tube is achieved, to which end the internal tube is acted upon from its inside by gas under pressure.

Abstract: The invention concerns a cooling plug for sizing the interior surface of thermoplastic extruded pipe. Vacuum and/or pneumatic pressure is applied at the surface of the plug. The pneumatic pressure may cause the inner wall to balloon outwardly to form bells within a mold or within an outer wall, to fit into corrugations of an outer corrugated tube, etc. The vacuum may be used to pull the inner wall back to the surface of the plug after application of pneumatic pressure.

Abstract: A forming assembly comprises two presser members (22,24) each having a corrugated surface for receiving a workpiece made up of generally diamond-shaped pockets (10). Each presser member is made up of sections (22a,22b; 24a, 24b) mounted on slide rods (38) for movement between a spaced-apart position, in which a workpiece can be located therebetween, and a closed position, movement into which, while the workpiece is held between the presser members, is effective to compress the workpiece laterally. For holding the pockets in their diamond shape formers (20) are inserted therein. A flange (18) is formed at one end of the workpiece and integral therewith by pressing outwardly folded material against a lateral end face of the presser members (22,24) using a presser plate (52). This forming method is especially suitable for forming self-supporting filter units.

Abstract: An apparatus for manufacturing an object having a relief structure on a surface thereof by pressing a first element provided with a negative of the relief structure against a second element to form the relief structure in the surface of the second element. The apparatus includes the first element and two pressure members having pressure surfaces facing each other and opposing both of the elements, the pressure members being moveable relative to each other in a direction transverse to the pressure surfaces.

Abstract: A method, process and apparatus for generating complex shapes without the use of dies, molds, or other fixed tooling. A continuous length or flow of a malleable or fluent material is provided to a forming apparatus which shapes the material, producing a contiguous series of smoothly blended, properly contoured portions of the desired shape. The formation of a shape relies on continuous control of shape-determining variables: the instantaneous cross-section of the shape in a virtual transition surface between the formable and formed material, the rate-of-change of cross-sectional dimensions between sequential cross-sections, the instantaneous angle of movement of the material at any point on the cross-section in the transition surface, and the rate of movement away from the transition surface of the just-stabilized portion of the shape. The material is stabilized as these shape-determining variables achieve the proper values in each portion of the material.

Abstract: An apparatus for forming tubular tile, including an endless trackway having at least two substantially straight portions defining first and second molding sections, a plurality of mold blocks supported for movement about the trackway, and a plurality of mating mold blocks supported for mating with the first mold blocks along each molding section to form a segment of a corrugated molding tunnel. Extruders introduce moldable material at the beginning of each molding section, and the material is conformed to the molding tunnel along the molding sections for forming the tile, with the mold blocks being separated when they move past the end of each molding section. The extruders are mounted for movement toward the beginning of the two molding sections when initiating tile formation therein.

Abstract: For the corrugated deformation of a flat sheet of material, an upper row (2) of shaping tools (4) is pressed against a lower row (3) of shaping tools (5). The shaping tools of both the rows are, with that, also simultaneously pushed together so that they trace the shortening of the sheet of material during the deformation. Thus, the situation is achieved where no relative displacement between the sheet of material and the facing sides (6, 6') of the shaping tools (4 and 5) takes place, also in the case of numerous corrugations of relatively great height. The lower row of shaping tools is arranged on a rotor, whilst the upper row is fixed at a working station within the area of rotation of the rotor.

Abstract: The device includes a toothed wheel on which pleats of a sheet 10 are preformed, in some cases with the aid of a second toothed wheel 31, and a device for holding by a vacuum; then the preformed pleats are transferred to a pleat gathering wheel 13 either directly or through the medium of a pleat pressing wheel, where they are laid down then fixed to form a pleated sheet 23. The toothed wheels 5 and 31 and the pleat pressing wheel and/or the pleat gathering wheel 13 can be arranged to produce areas with no pleats at regular intervals.

Abstract: The invention concerns an apparatus and process particularly for molding profile thermoplastic tubing and process. The apparatus includes the travelling mold type for molding profile tubing, e.g. corrugated or ribbed, including double walled tubing of various types. A sizing plug for the internal diameter of the pipe is provided with suction applying device which applies suction of diminishing strength in the upstream direction of the plug to the inside diameter of the pipe to provide a smooth inside wall of the pipe and allowing faster pipe formation. Suitably, the plug is a cooling plug and provision may be made for communicating the suction to cooling liquid to draw it to the surface of the plug to provide lubrication for a faster pipe forming process.

Abstract: For forming a resin-impregnated, fiber reinforced composite material sheet having laminated meshes of fibers into a U-shaped cross section, the sheet is placed onto a stationary forming die and an auxiliary forming die with the fibers of the sheet forming angles of approximately 45.degree. relative to opposite edges of an upper reference forming surface of the stationary die. Then, the sheet is pressed from above by a pneumatically expandable, elastic depressing die, whereby the auxiliary forming die is lowered against a resilient force relative to the stationary forming die. As the sheet is pressed further downwardly by the depressing die, the parts of the sheet which are to form flanges of the product are firmly held between the depressing die and the auxiliary forming die and bent downwards while the parts are subjected to extending forces in directions to prevent creases and lines from being formed by means of auxiliary forming ridges on the auxiliary forming die.

Abstract: A production line for manufacturing corrugated pipe also has a calibrating basin for manufacturing smooth-walled pipe arranged between form paths of the corrugator when the paths have been separated. An extruder that normally feeds a molten plastic pipe blank to the corrugator for making corrugated pipe then feeds the pipe blank to the calibrating basin for making smooth-walled pipe, and other down-the-production-line equipment can be the same, too.

Abstract: An apparatus is disclosed that engages a lid to a container by the formation of interlocking waves of lid material and container material. The interlocking waves are geometrically aligned relative to the interior of the container so as to maximize the burst strength of the container, and also to minimize the force required to peel the lid from the container. An unheated clamp head of the apparatus is used to clamp the lid structure immediately adjacent a heated seal head used to form the interlocking wave structure about the inside rim of the container, so as to prevent any melted portions of the container or lid from flowing to or toward the outside rim of the container, so as to prevent the formation of similar interlocking waves about the outside rim of the container.

Abstract: A corrugator for ribbing pipes includes two synchronously circulating chains of mold halves, a guide device for the mold halves having an input zone in which the associated mold halves are brought into engagement with each other, a molding zone in which a central channel is provided for guiding the engaged mold jaws and an output zone in which the mold halves are again separated from each other, as well as return guides for the mold halves on the path between the output and input zones and cooling apparatus for cooling at least the central channel with a coolant. A plurality of hollow profile modules is provided for forming the molding zone, each module being provided with a central cavity for the cooling apparatus and two lateral guide portions. Modules are arranged in pairs joining each other transversely of the production direction of the corrugator, and a plurality of module pairs are arranged adjoining each other in series in the production direction of the corrugator.

Abstract: Pipes with special profile sections are produced by an apparatus with circuit guided half shells. The half shells combining to form a mold have mold walls extending about parallel to a mold space axis. Vacuum slits extend about parallel to the mold space axis to open into a mold space in each case at a place radially the most distant from the mold space axis.

Abstract: The invention relates to a method and apparatus for manufacturing ribbed piping, wherein a formable mass in a plastic state is extruded into a substantially cylindrical forming space of a corrugator, the forming space being delimited by forming molds movable in the production direction of the apparatus and having grooves on the inner surface thereof for forming rib flanges. A stationary kernel portion of a mandrel cools the interior surface of the piping and extends beyond the forming space constituted by the forming molds of the corrugator.

Abstract: A process is described for precisely controlling the thickness of a thermoplastic extruded profile by varying the output of a continuously operating extrusion die. The process employs an ancillary device preferably taking the form of accumulator means connected to an extrusion die, or to a passageway communicating with the die. The accumulator means functions as a variable volume device, and by action of cylinder-piston structure or the equivalent thereof, is effective to either receive or discharge melted thermoplastic resin as the exemplary working medium. In this manner, the accumulator means receives melt from the stream when the die output needs to be reduced, and delivers melt to the stream when the die output needs to be increased. Various illustrative structural arrangements are disclosed for accomplishing the process concepts of the present invention.

Abstract: A method of making a prevulcanized tread particularly useful for the recapping of tires having, in stress-free condition, a constant curvature in its longitudinal direction whose radius corresponds substantially to that of the tires to be recapped, the sole of the tread being concave, is characterized by the fact that the tread has two ends in its longitudinal direction. The method includes feeding continuously a strip of raw rubber to an inner mold moving about an axis in a curved path, closing an outer mold for the tread pattern with the inner mold so that the closed molds form a continuous molding space within which the tread is completely molded and vulcanized as the closed molds move together about an axis of rotation, and opening the moving molds to discharge continuously in the longitudinal direction the prevulcanized tread of constant curvature.

Abstract: A process and apparatus for the manufacture of a pleated filter insert made of a thermoplastic material. The pleat walls are maintained at a distance with the filter pleats open in the direction of outflow of the filter insert by elongated ribs made of the filter material itself. The tape-like filter material is gathered in a first process step. The elongated ribs are produced by means of tension-free, permanent shaping of the gathered filter material, heated to a temperature which is below the shrinking temperature and above the deformation temperature of the filter material, between the jaws of a shaping device. The intermediate areas of the filter material intended for the forming of pleat wall edges are heated by at least one heater jaw to a temperature which is between the deformation temperature and the melting temperature until the irregularities of the filter material in the intermediate area have been smoothed out.

Abstract: A mold die includes a hexagonal base having six sides and six vertices disposed around an axis, and a tetrahedron having an apex aligned with the axis of the base. The base is integrated with the tetrahedron to form three congruent parallelogram walls, one vertex of each parallelogram wall being coincident with the apex of the tetrahedron, the other three vertices of each parallelogram wall being aligned with respective vertices of the base. The die further includes slots extending into the parallelogram walls parallel to the axis of the base. The die forms a tetrahexagonal walled cavity of a truss structure corresponding to the shape of the die, whereas the slots form perpendicular walls which structurally interconnect the apices of adjacent cavities and increase the rigidity of the truss structure.

Abstract: The invention concerns apparatus for molding thermoplastic tubing having solid annular ribs. The apparatus is of the type where a tubular mold is defined by cooperatively interengaged mold block of a pair of mold assemblies. An annular extrusion orifice for the tube extends into the mold tunnel and tubing is extruded about a mandrel. The invention provides an accumulator chamber in the region of the extrusion nozzle to provide for pressure differences which build up at that point. Thus, the effective volume of the accumulator chamber can compensate for the varying requirement for the thermoplastic material resulting from the varying radial wall thickness.

Abstract: A die having a plurality of walls for making a structure includes a die apex, a tetrahedron having tetrahedron edges and a tetrahedron apex that coincides with the die apex, and a hexagonal base located on the opposite end of the die from the die apex. The base is integrated with the tetrahedron such that three walls of the die are parallelograms having parallelogram edges, a first parallelogram vertex of each parallelogram wall intersects the tetrahedron apex, and the opposing second parallelogram vertex of each parallelogram intersects a base vertex. The parallelogram edges are milled down to allow plastic to flow between adjacent edges during a molding process and thereby form a truss structure comprising angled struts. A groove may formed in the parallelogram walls such that the groove joins a third parallelogram vertex with an opposing fourth parallelogram vertex in the parallelogram wall to form horizontal struts in a central portion of the structure.

Abstract: The invention concerns apparatus for making corrugated tubing. Mold blocks for formation of a travelling mold tunnel are provided with suction to the mold face by means of communication between suction passages in the mold block and a suction chamber. Each mold block has a channel which slidingly engages a track of the suction chamber to receive suction as the mold blocks travel over the track. Tongue and groove connectors are provided between the channel of each block and the track of the suction chamber and communication surfaces of the tongue and groove connectors to provide suction from the suction chamber to the mold face.

Abstract: A platen assembly is provided for manufacturing flat-topped wave-board. The assembly can be mechanically converted between a planar configuration and a wave-like configuration to form a board with a flat-topped and bottomed profile.

Abstract: This invention relates to a method and an apparatus for the production of ribbed pipes. According to the method a plastic material is fed through an extruder into a pipe molding space (12) defined by an extrusion sleeve (4), a mandrel (9) and chill molds (1, 2) moving in the direction of the central axis of the mandrel. When the pressure of the molding space (12) deviates from a desired value, a gap is formed between the chill molds (1,2), and plastic material is squeezed into the gap, or grooves (13) of the chill molds are filled up incompletely. In order to restore the pressure to the proper value, the pressure of the material contained in the molding space is directly measured by means of a pressure sensor (14) which adjusts the speed of the extruder or the chill molds.

Abstract: In the production of plastic tubes or pipes which are internally smooth-walled but have peripheral ribs externally, in particular from extrudable, more especially thermoplastic plastic such as PVC, a good filling of the cavities in the moving mold which are provided to form the ribs, is achieved in that said cavities are filled with the molten plastic first at a distance from the separating plane of the moving mold and last in the region of said separating plane.

Abstract: A method and apparatus for forming corrugated plywood composites is disclosed. The apparatus includes a fixed mold component having a corrugated surface and a series of movable mold components having complemental corrugated surfaces movable toward and away from the fixed surface. Movable mold components are hingedly connected and each such component is associated with a linear motor. By sequentially activating the linear motors each movable mold section is pivotally advanced in a first direction toward the fixed mold component the opposite side of the movable mold component being pivoted toward the fixed mold component when the next adjacent section is advanced into clamping position. High tensile strength low coefficient of friction fabric webs are interposed between the surfaces of the mold and the composite material to be corrugated.

Abstract: Method in manufacturing a heat insulated tube includes a tube (17) for conducting fluid and a sheath (12) enclosing said tube, a heat insulating material (15) being disposed between the fluid tube and the sheath. The sheath is being extruded in an angle extruder die (10) while the fluid tube and the heat insulating material enclosing said tube are being fed axially through the angle extruder die as the sheath is being extruded around the heat insulating material. Then the sheath (12) extruded from the angle extruder die is kept spaced from the heat insulating material (15) enclosing the fluid tube (17), over an initial length of the axial movement thereof up to chains of chill molds (13) for imparting to the sheath a corrugated shape by forming the sheath against the chains of chill molds under the influence of negative pressure. The invention also relates to a device in extruders having an angle extruder die (10) for the manufacture of the heat insulated tube.

Abstract: An embossing machine wherein two driven embossing rolls are provided with ripheral knobs and depressions. The knobs of one roll extend with clearance into the depressions of the other roll and vice versa during travel of the knobs and depressions through the nip of the rolls. The clearances between the top lands of knobs and adjacent portions of internal surfaces bounding the respective depressions are smaller than the clearances between the flanks of the knobs and the adjacent portions of the respective internal surfaces. This ensures that a carpet of loose fibrous material which is fed into the nip is converted into embossed textile material having a first layer of compacted portions which are formed adjacent the top lands of knobs on one of the rolls, a second layer of compacted portions which are formed adjacent the top lands of knobs on the other roll, and fluffy intermediate portions which connect the compacted portions forming one of the layers with compacted portions of the other layer.

Abstract: Apparatus for forming elongate laminate into a predetermined configuration having a substantially uniform cross-sectional shape in the axial direction, including a plurality of roller pairs having complementary transverse peripheral profiles, plate members disposed between the roller pairs and the laminate and having a transverse configuration corresponding to the peripheral profiles of the rollers.

Abstract: The present invention is directed to the manufacture of plastic tubing exemplified by corrugated plastic tile and parts related thereto, in which molds for shaping an extrudable plastic material are caused to shuttle linearly forwardly and rearwardly with respect to an extruding source of said plastic material. Sequentially related to linear mold movement is opening and closing mold action, which is correlated to the discharge of plastic material from the extruding source thereof. Provision is also made herein during the course of linear mold movement for parking one or more predetermined molds at a location spaced from the extruding source.

Abstract: An apparatus for producing a finned tube from synthetic plastics material has a moulding chamber which moves in the direction of production. Molten synthetic plastics charge enters this moulding chamber from which fins are moulded one after another, the fins being in each case formed individually one after another. In order to ensure this procedural measure, there are constructed in the surface of the molten plastics material present in the moulding chamber annular raised portions with conveying surfaces trailing in the direcetion of production. Corresponding conveying grooves are constructed in the half moulds which bound the molding chamber. These measures ensure an accurate contour of the tube which is to be produced, ensuring that a reverse flow of molten plastics charge and its combustion will be prevented.

Abstract: An apparatus for corrugating a flexible web containing heat softenable fibers comprising two pairs of endless drive chains with paddles mounted to each pair of chains to extend radially outward therefrom. The web is introduced onto the paddles at a point where the paddles are fanned out by passage of the paddles about the arcuate end of the endless chains. The web is folded between the paddles as the separation between the paddles is closed when the paddles move from the arcuate to the straight portion of the endless chains. Heating means soften and bond fibers of adjacent folds of the web together prior to removal of the corrugated web from the paddles.

Abstract: A method of forming a hole in a plastic pipe feeds a plastic layer for the plastic pipe from a nozzle about a mandrel into chill moulds being displaced along an elongated mould cavity about the mandrel formed by the chill moulds. All of the plastic layer is pressed into the chill moulds with a pressure medium between the mandrel and all of an inner surface of the plastic layer for forming the plastic pipe therefrom. Only portions of the plastic layer of the plastic pipe are then subjected to a local pressure difference exceeding the breaking limit of the plastic layer between the inner surface and an opposite, outer surface of the plastic layer at least in part from a flowing medium for forming a hole in the plastic layer of the plastic pipe, the flowing medium being one of a gas and a liquid and flowing from the mandrel at a pressure higher than that of the pressure medium pressing the plastic layer of the plastic pipe.

Abstract: This invention relates to an apparatus and a method for the production of outwardly ribbed, plastic pipes. The apparatus includes a core around which a plasticized material is pressed from a nozzle. A kernel having an essentially constant diameter is positioned at the terminal end of the core for a smooth inner face of the pipe. The outer face of the pipe is ribbed by grooves of axially displaceable chill moulds. The end zone of the kernel is provided for the cooling of the inner face of the pipe. In known apparatuses the grooves of the chill moulds are often filled incompletely and the inner face of the pipe becomes uneven on account of air bubbles, for instance. These disadvantages are avoided by heating an initial zone of the kernel for heating the inner face of the pipe and by shaping the surface of the initial zone to slightly expand conicallly in the production direction.

Abstract: The invention relates to a method and an apparatus for the extrusion of plastic pipes. Today, plastic pipes are provided with a sleeve in such a manner that the end of the pipe is heated, whereafter the end is expanded by means of a mandrel or a pressure medium. This step requires a separate sleeve machine, and it also takes plenty of time and consumes thermal energy. According to the invention a sleeve (22) is formed in connection with the extrusion of a pipe in an apparatus in which a mandrel (8) is surrounded by chill moulds (1, 2) moving in the axial direction of the apparatus. The sleeve is formed by providing some of the chill moulds with a recess (16) the shape of which corresponds to that of the sleeve (22) and by pressing a plasticized plastic hose (11) extruded through a nozzle (10) against the walls of the recess in the area thereof by means of pressure air.

Abstract: A method and apparatus for forming corrugated plywood composites is disclosed. The apparatus includes a fixed mold component having a corrugated surface and a series of movable mold components having complemental corrugated surfaces movable toward and away from the fixed surface. Movable mold components are hingedly in connected and each such component is associated with a linear motor. By sequentially activating the linear motors each movable mold section is pivotally advanced in a first direction toward the fixed mold component the opposite side of the movable mold component being pivoted toward the fixed mold component when the next adjacent section is advanced into clamping position. High tensile strength low coefficient of friction fabric webs are interposed between the surfaces of the mold and the composite material to be corrugated.

Abstract: A decorative hard boiled egg having a corrugated external surface is produced by placing a shelled boiled egg in a mold. The mold is provided with transverse circular corrugations or with longitudinal corrugations, the corrugations preferably taking the form of inwardly extending ridges alternating with inwardly concave surfaces. The egg mold may comprise a container and a plurality of molding elements interchangable with other molding elements to vary the aspect of the molded egg.

Abstract: A corrugator for molding externally ribbed and corrugated thermoplastic pipes, including two trains of moldblock halves circulating respectively in two endless paths and cooperating with each other to form a travelling mold for the thermoplastic pipes. The halves of one train are biased in relation to and overlap those of the second train along the travelling mold and are provided with intermeshing elements hooking the halves of the two trains together.

Abstract: The invention relates to an apparatus for the continuous production of pipes with cross-profiled walls from a pipe strand of thermoplastic plastic emerging in still plastic state from an extrusion nozzle.

Abstract: A continuous method of manufacturing a drainage system and apparatus therefore comprises a continuous assembly line which forms a plastic core material followed by continuously forming an envelope surrounding the formed plastic core and then sealing the stuffed envelope. In a preferred embodiment of the present invention, an extruder is used to transform granulated plastic material into sheet form. This plastic sheet is then fed directly into a plastic forming machine. The plastic forming machine will form a plurality of hills and valleys in the plastic sheet thereby defining a plastic core. Thereafter, continuous sheets of permeable fabric material are attached to the upper and lower surfaces of the formed core while the edges of the permeable fabric are secured to one another either by adhesive, sewing or any other suitable bonding method. Next, the draining system is either cut into desired lengths or rolled for shipping purposes.