Abstract: A method of providing closed-cell polyolefin foam having reduced blowing agent content to an end user including (a) extruding the polyolefin to form the essentially continuous foam structure defining a multiplicity of channels extending generally longitudinally therethrough; (b) intermittently crimping the essentially continuous foam structure such that the channels extending therethrough are intermittently substantially closed off; (c) intermittently severing the essentially continuous, intermittently crimped foam structure at the crimps therein to form discrete foam structure portions having crimped end portions; (d) cooling the crimped, discrete foam structure portions to an extent sufficient to prevent substantial shrinkage of the crimped, discrete foam structure portions upon initiation of release of the flammable blowing agent from the foam; (e) excising the crimped end portions from the remainder of the crimped, discrete foam structure portions to initiate release of the flammable blowing agent and for

Abstract: A series of driven rolls for separating blow-molded products from segments of flash material in a string of products formed in a synthetic resin continuous molding machine. A first pair of rolls receives a string of products joined by flashes as the products are removed from the dies of a blow-molding apparatus. At least one of the rolls in the first pair of rolls is driven at a first rotational speed. An intermediate pair of rolls receives the string of products and flashes from the first pair of rolls, and the intermediate rolls are driven at a speed faster than the first rotational speed to stretch the string of products and thereby separate the flashing segments from the products. A pair of last rolls is spaced by an interval from the pair of intermediate rolls. The interval between the intermediate rolls and the last rolls is adjusted such that the products and the flashes can be sorted by length.

Abstract: A method for manufacturing an one-end closed ceramic double tube, which includes the steps of extruding a ceramic double tube having inner and outer cylinders, drying the ceramic double tube, forming at least one passage in one end of the inner cylinder of the ceramic double tube so as to communicate an inner space of the inner cylinder with a gap formed between the inner cylinder and the outer cylinder, sealing the one end of outer cylinder proximate the one end of the inner cylinder, and firing the ceramic double tube.

Abstract: A multi-layer drawn polyester bottle has a neck portion having an opening on the top end and a fitted or screwed part on the periphery, a bottom portion formed by fusion bonding and closing of a pipe and a barrel portion biaxially molecularly oriented by draw-blowing of the pipe. The pipe is composed of a co-extrudate of inner and outer surface base layers of polyethylene terephthalate and an intermediate layer of an ethylene-vinyl alcohol copolymer having an ethylene content lower than 50 mole %. This multi-layer drawn polyester bottle is prepared by co-extrusion a multi-layer pipe using the coextrudate and, if necessary, interposing an adhesive layer between the two resin layers, cutting the pipe into a predetermined length, closing one end of the cut pipe by fusion bonding to form a bottom portion, forming the other end of the cut pipe into a neck portion having an opening on the top end and a fitted or screwed part on the periphery, pre-heating the so-obtained preform at a drawing temperature of 85.

Abstract: An apparatus and method for the manufacture of plastic couplings for joining together two lengths of plastic pipe. The couplings are manufactured from blanks of plastic material, such as polyvinyl chloride, which are heated to the thermoplastic state. The blanks are expanded between two mandrels which come together inside the ends of the blank. The mandrels have an outer member with a thin walled section and a nosepiece inside of that section which collapses at the end of the inward stroke of the mandrels so that the center shoulder of the coupling is not as wide as that of the prior art coupling. This results in a coupling which is shorter and lighter than the prior art coupling and yet is the full equivalent of the prior art coupling.

Abstract: Thin-walled catheters are provided which have an elongated fuseless polymeric tube that is made from a single tube of extruded polymer. The elongated fuseless polymeric tube includes a body portion that had been subjected to a high temperature zone in order to solid state polymerize and enhance the mechanical stability, burst strength and kink resistance of the body portion. Also included is a tip portion of the elongated fuseless polymeric tube which was subjected to a low temperature zone to retain the initial properties of extruded polymer.

Abstract: A method of making a microwaveable hair curler is shown in which a silicone rubber composition is extruded through a die and then cut to a desired length. The silicone rubber composition is blended from a polyorganosiloxane gum, a particulate electromagnetic absorptive material, a filler and a catalyst.

Abstract: A method is provided for making a splittable introducer catheter by co-extruding two different polymers of differing solubilities, so that v-shaped strips are formed on each side of the catheter wall which may be easily stripped from the main catheter tube. This leaves an introducer catheter which is easily split along the narrowed v-shaped grooves on diametrically opposite walls of the catheter.

Abstract: An injection molding process for making a multiple layer, plastic structure. A plastic sleeve is placed and then enclosed in a mold cavity. A flowing heated plastic is conducted into the mold cavity, radially inside the sleeve, and forced radially outward against the sleeve. The flowing plastic forces the sleeve outward and forms, with the sleeve, an integrally bonded laminated structure. The mold is opened and the plastic structure is removed, and this structure may then be reformed to form a container particularly suitable for containing beverages, foods, cosmetics, pharmaceuticals and chemicals.

Abstract: A method of extruding ceramic bodies in a downward direction is disclosed, which includes the steps of supporting an extruded body being downwardly extruded through an extruding die to prevent deformation of the extruded body, and cutting the extruded body in a given length. An apparatus for effecting this extruding method is also disclosed, which includes an extruding unit provided with a die at a bottom thereof, a unit for holding the extruded body being downwardly extruded, and a cutter for cutting the extruded body in the given length.

Abstract: Electroweldable pipe sockets and fittings by forming a first tube being internally sized and cooled and on the outer side provided with a groove, having preferably a raised edge part, winding an electrical conductor in the groove, and the outer side of the first tube with electrical conductor is coated with plastics thereby maintaining the internal size of the first tube by internal cooling and sizing. In this continuous process the speeds of the first tube and of the continuous tube leaving the coating extrusion stage are equal. In the coating extrusion stage a negative pressure is maintained between the first tube and the coating to be applied.

Abstract: Non-releasable, double-walled, molded, large-diameter, corrugated plastic pipe having walls made of high density polyethylene, PVC or polypropylene of sufficient thickness so as to be rigid but elastic and therefore relatively inflexible and having an integral automatically locking female coupling at one end, with access to its latching members at its exterior, and a method of manufacturing multiplex thereof by a continuous molding process. The pipe has a smooth interior wall and a corrugated outer wall integral therewith. Only minor auxiliary cutting operations are required to separate portions thereof into individual plastic pipe sections, each having the automatic-locking coupling at one of its ends. The coupling is supported on the corrugated pipe by a frustoconically shaped collar which functions as a guide for proper alignment as two sections of pipe are united into latched relation.

Abstract: A method of terminal treatment for an extrusion molding of the present invention including the steps of: applying double-sided adhesive tape to necessary positions of an extrusion molding; cutting the extrusion molding with the double-sided adhesive tape stuck thereon into a necessary length; cutting a release paper of the double-sided adhesive tape into a predetermined length less than the necessary length of the extrusion; and forming a terminal of the extrusion into a predetermined form by injection molding.

Abstract: A method of manufacturing soft tip catheters having inner rigid polymer layers and outer soft, pliable polymer layers. The method involves first extruding the rigid polymer at varying extrusion rates to form a cylindrical body having a depression at one or more prescribed locations. The outer layer is formed by extruding the soft, pliable polymer over the inner to fill in the depressions. The resulting cylindrical body is then cut to form individual catheters having soft tip as defined by a portion of the prescribed locations.

Abstract: The present invention relates to a method and an apparatus for tubularly drawing a tubular raw material of thermoplastic resin. Gas for forming a bubble to heatingly draw the tubular raw material is injected into the raw material from a direction opposite to a direction for transferring the raw material through a nozzle. The raw material is cut into a plurality of web-like pieces by cutting blades provided on pinch rolls for taking up the raw material. One of the web-like pieces thus cut is separated from the others and formed with an opening into which the nozzle is inserted to inject the gas.

Abstract: Long lengths of a heat-shrinkable sleeve for use in splicing electrical cables and the like are manufactured by providing an elongated impermeable core having a smooth outer surface, extruding an elongated sleeve around and in contact with the core, the sleeve having a smooth inner surface conforming to the outer surface of the core, and effecting an initial expansion of a portion of the sleeve to a larger diameter in an expansion zone so that the sleeve separates from the core and leaves a space between the sleeve and core. A fluid is introduced into the space under pressure via a fitting at the downstream end of the sleeve while continuously advancing the sleeve and core through the expansion zone. To begin the process, a permeable core is used, and the sleeve is extruded around and in contact with the permeable core.

Abstract: A method for manufacture of a sealing ring with a flanged sealing lip having hydrodynamically acting return transport properties in which a sealing lip is first generated by extrusion of a plastically deformable material through a ring nozzle having rotating inner and outer surfaces which are rotated relative to each other to impart a helical motion to the extruded material; the hydrodynamically acting return transport properties being a microscopically fine pleating of the surface of the extruded hollow cylinder. The extruded cylinder is then solidified and cut to a predetermined length. The cylinder is then widened in the radial direction at its front end by an assembly tool which shapes the cylinder into a trumpet-shaped sealing ring with a flanged sealing lip.

Abstract: A retreading envelope is produced by extruding an elastomeric material in substantially tubular form, with portions of the wall thickness of the circumference of the extruded tubing being of a thickness substantially greater than the wall thickness of the remainder of the tubing, cutting a length of the extruded tubing from the tubing as extruded, and butt-seaming the free ends of the cut length to form an annular tube substantially of circular cross-section, with the thickened wall portions of the extruded length in the area of its outer periphery. The elastomeric material in the thickened wall portions of the annular tube is then caused, e.g.

Abstract: This invention relates to a process of making flat stock fibrous cellulosic food casings containing a low plasticizer level of between about 10 wt. % and about 17 wt. %, including at least about 9 wt. % polyol, both based upon the bone dry weight of cellulose in the casing, This process comprising forming a fibrous web into a tube, annularly extruding viscose onto the tube, passing the viscose coated tube through a regenerating bath, and incorporating water-soluble plasticizer into either or both the resulting cellulosic gel stock fibrous tube and the dried fibrous tube.

Abstract: An extruded thermoplastic polymer conduit having a conduit wall of substantially uniform crystalline morphology through the entire thickness thereof free of any oriented surface zone is formed by heating to melt the surface zone and cooling to recrystallize the surface zone.

Abstract: A process for making a reinforced tubular product, especially a catheter, in a single extrusion step. A reinforcing member is heated when applied to an extruded thermoplastic catheter body of about its finished size which is softened by heating while tensioning the reinforcing member to control the surface deformation or penetration of the catheter wall by the reinforcing member to produce an irregular surface contour on the catheter body. The catheter body is then smoothed in a sizing die burying the reinforcement to form the finished product. The heating step may be in addition to or substituted by a curing step when a thermosetting or crosslinking material is used for the body. The reinforcement may be braid, or a helical wrap of one or more members applied at one or more controlled angles relative to the axis of the catheter to control the strength and torque transmission efficiency of the catheter.

Abstract: Shaped ammunication for tubular weapons in the form of nitrocellulose-based combustible cartridge cases are continuously produced in a screw extruder from an aqueous suspension, stabilizers, flammable fibrous material, binders and optionally plasticizers being supplied to the suspension. The fibre-like constituents are matted in kneading and pressing zones, accompanied by the simultaneous squeezing out of the water, being shaped to an endless tubular structure, which is then cut to the length of the individual cartridge cases and is optionally also pressed to the desired dimensions and shape. Advantageously use is made of a double shaft screw extruder with kneading and pressing segments, as well as a water outlet, which is provided at its end with a tubular die. A following pressing and cutting to length means is arranged behind the extruder.

Abstract: An end component 3 is spin-welded into the cut end of an extruded tube 1 with the application of axial pressure but without the application of radial pressure to the weld area. The radial forces required to create a weld are provided by hoop stresses which are formed in the tube by shock-cooling the tube as it emerges from the extrusion die. When the tube is cut, the hoop stresses cause the cut end of the tube to contract radially prior to insertion of the end component. To assist in insertion of the end component, a cylindrical skirt thereof 4 is provided with a chamfered end 9.

Abstract: A method is providing for making a thin-walled catheter of the type having a distal end adapted to be formed into a curve and guided through branching blood vessels or the like so that the catheter is provided with a two-layered tubular body portion having a rigid inner sheath and a flexible outer sheath, which may be radiopaque. The catheter exhibits excellent torque response and control while being especially thin-walled, thereby permitting minimization of the outer diameter size while providing excellent liquid flow rates therethrough and excellent strength properties. The tip portion is fuseless with respect to the rest of the catheter, the tip portion being an integral extension of the flexible outer sheath that is formed over a gap between lengths of the rigid inner sheath.

Abstract: A monolithic, block-type heat exchange element having a series of fluid channels is manufactured by making use of extrusion molding. Extrudable molding material is extruded to form a continuous molding having opposed first and second surfaces. The extruded molding is provided with a series of discrete first passages and another series of discrete second passages both extending along the direction of extrusion and between the first and second surfaces. The molding is transversely cut into sections. At least parts of the molding section are then cut out along the first and second surfaces until the first passages are opened into the first and second surfaces. The openings of the first passages opened into the third and fourth surfaces extending perpendicular to the direction of extrusion are closed by suitable closure material to form a series of first fluid channels for a first heat exchange medium.

Abstract: A method is shown for forming a spark plug boot having at least one internal shoulder. An outer tube is first formed of an elastomeric material having an internal bore and a selected length. An inner tube, also formed of an elastomeric material, is inserted within the bore of the outer tube. The inner tube has an external diameter selected to allow it to be slideably received within the bore of the outer tube and has a length which is less than the length of the outer tube. The inner and outer tubes thus assembled are then exposed to electromagnetic radiation for a time sufficient to bond the external diameter of the inner tube to the internal bore of the outer tube.

Abstract: A process of forming biaxially oriented tubular articles by repeatedly performing a cycle of operations which includes engaging a thermoplastic tube by a first clamping member over a first region at a trailing end of the tube and engaging the tube by a second clamping mechanism over a second region at a spacing from the first region so as to define between the clamping mechanisms a portion of the tube to be longitudinally stretched and radially expanded; moving the clamping mechanisms apart to stretch the tube portion therebetween longitudinally; admitting pressure fluid into the tube portion to expand it radially and form a biaxially oriented bubble adjacent the leading end of the tube, and severing a substantial part, but not all, of the bubble from the tube to form the tube with a radially outwardly flared end as the leading end of the tube for the succeeding cycle of operations.

Abstract: Pharmaceutical compositions are provided which contain hollow fine tube drug delivery systems. The compositions comprise a pharmaceutically suitable carrier, preferably in the form of a capsule, tablet, suspension, or suppository, and at least one drug delivery system which consists essentially of (1) a polymeric tube having a membrane outer sheath and a hollow core, and (2) at least one drug compound contained within the core, said system contained in the composition in an amount sufficient to deliver a therapeutic amount of the drug contained therein at a predetermined rate over a predetermined period of time. By varying the polymer, the permeability of the outer sheath, the drug, the drug concentration in the hollow core of the tube, the tube diameter, the tube length, the tube core diameter, and the sealing of the tube ends, a wide variety of drug therapeutic amounts, rates and dosing times can be achieved.

Abstract: Apparatus and method are provided for straightening a parison tube (58b) in an apparatus of the type in which thermoplastic tubing (48) is extruded into open halves (24 and 26) of a blow mold (22) and a parison tube (58b) is severed from the thermoplastic tube (48) concurrently with the blow mold being rotated around an axis (28). The present invention orients the curvature of the parison (58b) in a predetermined plane (52) by accelerating the parison tube (58b) transversely to the axis (90) of the parison tube (58b); and then the parison tube (58b) is straightened by applying jets of air (76) against the neck and moil portion (68) of the parison tube (58b), thereby straightening the parison tube (58b), and thereby preventing the neck and moil portion (68) of the parison tube (58b) from being pinched between the mold halves (24 and 26) in the area of the neck and moil cavity (38).

Abstract: A flexible cable assembly for actuation of an automobile speedometer or the like, comprising an inner core member and a tubular casing that includes an outer housing and a spiral-cut tubular liner with multiple internal ribs. The liner is constructed by extruding a cylindrial tube with at least one internal longitudinally extending rib. The tube is then cut helically so as to offset circumferentially the rib segments on adjacent turns of the strip, providing multiple internal supports for the core member.

Abstract: A process of stretching tubular nets or plates made of extruded plastic material according to one or two directions at right angles to each other and an equipment for carrying out the same wherein said process consists in dipping the tubular net or plate into heated water, in causing it to be fitted on a substantially flat and wedge-shaped means, dipped into heated water too, and in cutting said net or plate close to at least one of the sides of said wedge-shaped means; and wherein said equipment consists of a substantially flat and wedge-shaped means disposed on a bearing casing and defined by a plurality of driving and idler pulleys disposed symmetrically two by two with respect to a vertical median plane of the equipment, in order to substantially define a wedge, said pulleys being drivingly connected to each other by at least a driving belt.

Abstract: Apparatus for preparing seamless, creaseless, pliable, thin-walled tubes comprising means to extrude a moving continuous tube of polymeric film material from a die, means to radially stretch the continuous tube as it emerges from the die, means to longitudinally stretch the tube, and means to sever the tube while the tube is in motion to form tube segments while maintaining the tube substantially free of creases. This apparatus may be employed in a process to prepare seamless, creaseless, pliable, thin-walled tubes.

Abstract: Disclosed is a method of and a device for producing bundles of hollow fibers such as used for dialysis. The device includes a guiding device for a continuous fiber which rotates in a plane. At least two groups of take-up elements are mounted on a conveyor. The conveyor is intermittently activated so that a group of take-up elements is placed in a working position in the range of movement of the guiding device, and a strand of a desired thickness is wound around the take-up elements. Thereafter, the conveyor is activated to discharge the first group together with the completed strand from the working position and place the subsequent empty group of take-up elements in the working position, without interruption of movement of the guiding device. During the winding-up of the subsequent strand, the completed strand is cut and wrapped into bundles.

Abstract: Disclosed is a non-fused torque control catheter and a method for manufacturing such a catheter. This non-fused catheter has a stiff braid-reinforced body and a pliable non-braided tip.

Abstract: A coextrusion head for producing a generally tubular elastomeric ply made up of first and second concentric tubular streams of elastomeric material having interposed, adjacent to their interface, a closely spaced array of parallel reinforcing elements wherein the coextrusion head includes a reinforcing element guide subassembly including a generally annular guide element as well as a mechanism for individually and independently directing and accurately positioning a circular array of uniformly spaced individual reinforcing elements.

Abstract: A thin-walled guiding catheter of the type having a distal end adapted to be formed into curved configurations and passed through branching blood vessels and the like is prepared with a three-layered tubular body portion having a lubricious inner sheath defining a lubricious guiding lumen, a rigid intermediate sheath, and a flexible outer sheath, which may be radiopaque. The distal tip portion thereof has a similar construction, but from which the rigid intermediate sheath is omitted. The guiding catheter exhibits excellent torque response and control while being especially thin-walled, thereby permitting minimization of the outer diameter size while permitting passage of an intravascular catheter and the like through its lumen.

Abstract: This invention relates to an extrusion method of preparing tubular green bodies, in particular those having thin walled thickness, which after burnout and sintering have properties similar or better than those of tubular bodies produced by isostatic pressing and are suitable for use in the sodium/sulfur battery. The method comprises extruding a mixture of 40-60 volume percent of sinterable particulate solids consisting essentially of a particle size distribution of beta"-alumina precursor particulate comprising alpha-alumina and 60-40 volume percent organic sacrificial binder consisting essentially of a thermoplastic block copolymer, plasticizers comprising two oils and two waxes, stiffening thermoplastic polymers and processing aids. In the preferred embodiment, the composition of the particulate comprises 8.85 weight percent Na.sub.2 O, 0.75 weight percent Li.sub.2 O and 90.4 weight percent Al.sub.2 O.sub.3 and the temperature of the material is maintained between about 135.degree.-150.degree. C.

Abstract: A method of manufacturing a fistula consisting of a needle mounted on a plastic handle or wing. The plastic wings are formed by continuously extruding a plastic strip having the wing cross section. The outer end of the extruded plastic is blanked to partially shape and outline an individual wing. Thereafter, a needle is inserted into a hollow core on the endmost partially blanked wing and a needle guard is positioned over the needle. Finally, the completed fistula is removed from the end of the extruded strip by a final cut or punching for producing a finished fistula.

Abstract: Method of manufacturing synthetic resin pen nibs is disclosed, which pen nibs may suitably be employed in writing instruments for fine lettering or drawing fine lines. The pen nibs are formed of thermoplastic crystalline synthetic resin, e.g. polyethylene terephthalate resin, which is extruded from a molding die and subjected to rapid cooling to form a continuous rod in amorphous state. The rod is axially stretched under predetermined temperature condition to achieve oriented crystallization of the resin molecules, and is further heat-treated such that non-oriented fine crystals are dispersed and grown between oriented crystals and remaining amorphous regions. Pen nib thus obtained has highly improved physical and chemical properties.

Abstract: For heat-setting tubular articles (such as can bodies) of an at least partly biaxially oriented crystallizable polymer, preferably a saturated linear polyester such as polyethylene terephthalate, e.g. for thermally processable food containers, a tube of the polymer is fitted over a mandrel and clamped at its ends to the mandrel at a temperature below the glass transition temperature of the polymer. The tube is then heated, e.g. by inserting a heater 28 into the interior of the mandrel, above the temperature to which it is to be heat-set (at least 60.degree. C. above for PET) whereupon it shrinks into contact with the mandrel but is restrained from axial or further radial shrinkage. The tube and mandrel are cooled to below the heat-set temperature and the tube may then be cut into can body sections by knives engaging in circumferential grooves. Contact between the tube and mandrel is released, e.g.

Abstract: In a tape which is driven by an elastic pretensioned belt, discontinuities such as embossings in the surface of the belt promote the release of air from between the belt and the underlying tape, thus minimizing variations in tape tension and tape speed.

Abstract: A self-raising post of a plastic material, such as PVC, for use as a roadside marking post, a traffic sign post, a lamp post, or for other comparable uses in road traffic environments, has a channel-shaped bending zone with substantially arcuate cross-section and with the convex side facing the on-coming traffic. The cross-sectional area of the bending zone increases progressively towards the lower end, whereby the flaring-out zone formed upon bending of the post will be larger below than above the line of bending. The greater inherent resiliency of the material below than above the line of bending will cause the post to bend back into an upright position after having been hit by a vehicle. Certain embodiments of the posts are manufactured by diagonally splitting lengths of extrusion-molded plastic tubing, forming two identically shaped posts from each tube length.

Abstract: A method of forming a spark plug boot which utilizes an extrusion process. An elastomeric tube is extruded, then heated to a partially cured condition. The tube is then cut into individual pieces. The individual pieces are stretched over a pin which has at least one external shoulder. The pin and tube are then heated to a temperature and for a time to provide a final cure. The tube is stripped from the pin. The compression set and shrinkage results in an internal shoulder in the tube, allowing it to serve as a spark plug boot.

Abstract: A method of treating polypropylene hose to increase its strength and durability is provided by flexing the hose through a plurality of 360 degree rotations while in a bent form to alternately axially compress and extend portions of the hose to increase the molecular alignment of the polypropylene.

Abstract: A method of making imprints on the walls of portions of a tube obtained by the continuous molding of a ceramics-based paste and the cutting up of the tube, wherein immediately after the tube portions have been molded and are still deformable, they are placed on means parallel with the axis of the tube portions for rotating them around their axes of revolution, means are applied to the rotary means for exerting a pressure on at least a portion of the tubes so that such portions are clamped between the rotary means and the pressure-exerting means, the pressure-exerting means or the rotary means are provided with at least one imprint-making tool, the or each tool having a main direction which does not coincide with the direction of the axes of revolution of the tube portions, and means are applied to create a second relative movement between the tube portion and the or each tool, so that there is substantially no sliding between the tube portion and the or each tool.

Abstract: An elastomeric spring is formed by extruding a rubbery material into a reinforcing sleeve in a mold during relative motion between the mold and nozzle, and thereafter vulcanizing.

Abstract: Extrudable thermoplastic molding material for manufacturing plastic sheeting used in protective covers, especially for vehicles and parts thereof, characterized in that the extrudable thermoplastic molding material for the manufacture of plastic sheeting is a combination of different polyethylenes and olyamides consisting of1. at least 45% by weight of linear polyethylene (LLDPE),2. 10-50% by weight of high-pressure polyethylene (LDPE),3. 0.5-10% by weight of low-pressure polythylene (HDPE),4. 0.1-5% by weight of olyamides or eurocamides and natural silica, and5. up to 5% by weight of fatty-acid esters, dyes, synthetic silicic acid, stabilizers, and processing agents,with the sum of 1-5 always being 100% by weight and method of manufacturing from this material a plastic sheeting that is highly elastic, grip-resistant, and smooth.

Abstract: A tire for a wheelchair wheel or the like in the form of a composite extrusion comprising a relatively soft, elastomeric casing extruded over a semirigid core. End faces of a length of extruded stock are joined by thermal fusion developed by a ferromagnetic element inserted in the tire and exposed to high frequency electromagnetic radiation.

Abstract: A process for the production of articles consisting of ceramic material comprises the steps of: extruding a starting material which is of a plastic consistency and contains clay to form a string having at least one longitudinal channel; drying, firing and cooling the string; passing a gaseous medium, for example air, through said at least one longitudinal channel of the string or sections thereof; and subsequently dividing the string or sections thereof into individual articles. There is also provided an apparatus for carrying out the process.

Abstract: The present invention concerns manufacture of cellular structures of thermoplastics material. In particular the invention concerns apparatus for use in the production of cellular structures of thermoplastics material comprising a supply and injection stage (b) for supplying the thermoplastics material (12), a die stage (c) through which the thermoplastics material supplied by the supply and injection stage is extruded to form the cellular structure (15), and a cooling stage (d) supplied in use with cooling fluid (4) for cooling the extruded thermoplastics material, the different stages being located one above the other and the apparatus further comprising a plurality of regularly spaced cylinders (7), each cylinder (7) having a lower part (10) of lesser diameter provided with heating means (11) and an upper part (8) of greater diameter, the bodies of the cylinders extending through the supply and injection stage and the upper parts thereof forming said die stage.