Abstract: A method of and an apparatus for providing a bubble-free coating on a fibre, more particularly on an optical fibre. A fibre to be coated is fed into a pressure chamber (61) via an inlet duct (56) with a restricted inlet opening (57) and leaves the pressure chamber (61) through an outlet opening (41) of a nozzle (40). Liquid coating material is supplied to the pressure chamber (61) at such a pressure that the coating material rises in the inlet duct (56) up to a certain level to form a convex meniscus (D). By flushing the surroundings of the inlet opening (57) with a gas having a kinematic viscosity which is lower than that of air, the drawing speed at which the applied coating is still bubble-free can be considerably increased.

Abstract: The inventive means includes a supply vessel (10) having a bottom opening (14), feed means (15 to 17) for supplying the vessel (10) with solid silicon and means (11 to 13) for heating the vessel, said vessel being placed above the crucible (1) containing the melt (8) so that the molten silicon in the vessel (10) flows out through the bottom opening (14) into the crucible (1) when the level (h) of the molten silicon in the supply vessel reaches a maximum value (20) and the replenishing flow stops when the level (h) has fallen to a minimum value (22). An application involving the deposition of a layer of polycrystalline silicon onto a carbon tape is described.

Abstract: A die bar having an integral locking means for selectively engaging transport cables located along the process path of a wire coating apparatus is disclosed. The locking means allows for a die bar to be threaded with wires while in a stationary position, then to engage transport cables which draws the wires along the process path until the die bar reaches a satisfactory position in the process path, where the locking means are released. Claims disclosed are drawn to a die bar with integral locking means, and to a method of transporting wires along the process path using the disclosed die bar.

Abstract: A cable lubricating device (1) including a split housing (2). Lubricant (25) is introduced into the housing through a vertically oriented orifice (6), the cable (37) advancing in a generally horizontal direction. A coupling adaptor (59) permits withdrawl of lubricant by a standard fitting (64) without danger of the collapse of hose (56) even at high lubricant discharge pressures. A series of sponges (18, 19) apply lubricant to the cable in a metered fashion. A method is also disclosed wherein lubricant may be "preloaded" into conduit (26) to enhance uniform lubricant distribution.

Abstract: There is disclosed a bushing for use in an apparatus for continuously passing a core wire through a crucible holding molten metal to accrete the molten metal on the core wire to form a cast rod. The bushing is connected to the crucible for passing the core wire therethrough into the crucible. The bushing is tubular and has an engaging portion for engaging with the core wire passing therethrough. The engaging portion is made of ceramics material containing a major proportion of at least one selected from the group consisting of zirconia, silicon carbide and silicon nitride.

Abstract: An apparatus and a method for controlling the thickness of coatings on webs at a plurality of cross-directional positions while a coating procedure is taking place. The deflection of the metering element is controlled automatically in response to measurements of the uncoated and coated web that determine the thickness of the coating being applied at a plurality of cross-directional positions. In one preferred embodiment, a bimetallic member having a plurality of separated tongue-like extensions corresponding to cross-directional positions along the blade is used, the tongue-like extensions pressing on the back of the blade at their ends in response to heat applied dependent upon the determined thickness of the coating being applied. In another embodiment, pneumatic actuators whose pressure may be varied in response to the determined thickness are used to adjust the position of the metering element at a plurality of cross-directional positions to locally vary the thickness of the applied coating.

Abstract: Dynamic flood conveyor. The conveyor permits a chemical solution to be applied to the surface of a material such that the solution interacts with the material at a generally uniform rate at each point on the surface of the material. The apparatus promotes laminar flow of the chemical solution over the surface of the material.

Abstract: A die bar carrier (40) has a beam (42) to support the die bar (10) having wire (20) threaded therethrough, an attachment spring (60) to couple the beam (42) to a pulling mechanism (70), and a wire retainer (50) that is spaced from the beam (42) to hold the wire (20) between the beam (42) and the retainer (50).

Abstract: A method and a device for applying a primary coating to an optical filament. In order to make the distribution of the coating material even, the flow of the coating material to be introduced into the crucible is divided in the crucible into two flows opposite in direction and advancing in the peripheral direction of the crucible. The two flows are caused to flow in the axial direction substantially at the opposite sides of the crucible. The axial flows are caused to flow in the peripheral direction of the crucible and joined by means of an outer channel extending around the crucible in the peripheral direction thereof. The flow is passed radially through throttle openings into an inner peripheral channel and further through a peripheral throttle slot into a conical channel along which it is led into a central chamber of the crucible, through which chamber the filament is drawn.

Abstract: A method of and an apparatus for providing a bubble-free coating on a fibre, more particularly on an optical fibre. A fibre to be coated is fed into a pressure chamber (61) via an inlet duct (56) with a restricted inlet opening (57) and leaves the pressure chamber (61) through an outlet opening (41) of a nozzle (40). Liquid coating material is supplied to the pressure chamber (61) at such a pressure that the coating material rises in the inlet duct (56) up to a certain level to form a convex meniscus (D). By flushing the surroundings of the inlet opening (57) with a gas having a kinematic viscosity which is lower than that of air, the drawing speed at which the applied coating is still bubble-free can be considerably increased.

Abstract: A device for coating traveling material webs wherein the coater features two opposite press rolls capable of forming therebetween a coating mixture sump. Each press roll features at its side opposite from the other press roll a coater provided with a doctor blade. In the application of sizing to the web, the last reversing roll in the direction of web travel is arranged above the press rolls. In the application of coating, to the web, the last reversing roll located in the direction of web travel before the first coater is arranged below the two press rolls.

Abstract: A split coating head assembly for elongated strands, the assembly comprising first and second mounting blocks with first and second die components respectively mounted therein, the die components defining therebetween a coating chamber which is in communication with a pressurized source of coating material, the die components forming upper and lower apertures for drawing of the strand vertically therethrough, and through the coating chamber.

Abstract: An apparatus for coating a vertically travelling web comprises a vertical coating chamber defined by the web, a pair of side walls, a back wall spaced from the web, and a flexible blade applied against the web and forming a top closure of the coating chamber. There is a back-up member at the opposite side of the web forming a coating nip together with the flexible blade, through which nip the web passes. A slot at the bottom of the coating chamber forms a web entrance of the coating chamber. The width of the slot and the supply of coating substance to the coating chamber are so adapted to the speed of the web and to the viscosity of the coating substance, that only a small amount of coating substance flows downwardly through the slot during normal operation of the apparatus. The side walls of the coating chamber provide means for substantially closing the coating chamber.

Abstract: The size applicator includes first and second spaced-apart squeeze rolls supported for rotation on a common horizontal axis and having their lower peripheral surface portions at least partially submerged in size solution contained in an open top pan. A single combination immersion and squeeze roll is positioned between the first and second squeeze rolls and on a common horizontal azis with said first and second squeeze rolls. The lower peripheral surface of the combination immersion and squeeze roll is also at least partially submerged in the size solution and pressure engagement is applied between the combination roll and the first and second squeeze rolls to form a pair of yarn squeezing nips therebetween.

Abstract: A method and apparatus for cooling metal wire or strip being drawn vertically from a hot dip bath and between a pair of refractory wiping pads. The wire or strip passing between the wiping pads directly into a chamber containing a cooling liquid which is supported above and at least in part by the wiping pads. The chamber having inlet and outlet means for the cooling liquid and a removable wall to allow more rapid draining of the chamber and access to the inside of the chamber for changing the wiping pads and/or re-threading the wire.

Abstract: A continuous rod of a product such as cigarette filter material is coated with a treating liquid by being passed axially through a cylindrical applicator zone comprising a permeable cylindrical wall, the cylindrical wall being concentrically enclosed within a reservoir and manifold zone connected to a source of liquid. The feed supply for the liquid additive can be pressurized and/or heated, so that application of the additive can be in either liquid or vapor form. The process and apparatus of this invention may be used alone or in conjunction with prior art homogeneous applicators and processes.When used to apply a plasticizer to a rod of continuous filament tow, e.g. for use in producing cigarette filters, annular regions of varying concentrations of the plasticizer are produced in the rod. A relatively dense region of plasticized fiber can be produced on the outside of the filter. Filter rods having wrapping paper uniformly adhered about the periphery of the rod can be produced.

Abstract: In providing a dried insulation layer upon conductor, a covering fluid layer is initially provided by apparatus in which the layer is formed from composite material comprising magnetically permeable particles homogeneously mixed with a fluid carrier. The fluid layer is formed by passing the conductor through a reservoir of the material and then vertically through a die orifice. The reservoir of fluid applies pressure at the die orifice and this pressure is adjustable to vary the rate at which the material passes through the orifice and thus varies the diameter. This pressure is controllable by adjusting the height of the reservoir above a die orifice or by adjusting gas pressure acting downwardly upon the material. The diameter of the layer is advantageously monitored after it is dried and variation in monitored diameter from that desired effects a change in pressure to alter the diameter towards that desired. The diameter of the layer may, however, be monitored with the layer in fluid form.

Abstract: An arrangement for coating a fibre, more particularly an optical fibre, comprising a housing (31) with a pressure chamber (61) which is in communication with a connection (63) for the supply of liquid coating material. A fibre to be coated is supplied via a guide duct (59) in a tubular guide member (55), traverses the pressure chamber (61) and leaves the device (11) via an outlet opening (41) in a nozzle (40). The tubular guide member (55) is made of an elastically deformable material. By means of two spindles (79), the end of the tubular guide member (55) can be adjusted so that the coating is centered with respect to the fibre and a coaxial location of fibre and coating is obtained.

Abstract: A method and apparatus for impregnating strands of fibers with resin are disclosed. The resin is recirculated through the interior of a substantially closed container. The strands are pulled through the interior of the container in essentially a straight line manner. The fibers in each strand are spread by running them across a plurality of transversely extending bars in the interior of the container while the fibers are immersed in the resin.

Abstract: Disclosed is a coating die which has a dilatable orifice, the orifice being dilatable due to the use of a flexible, resilient portion of the die. The die is individually cast and is "strung-up" in the casting process. The preferred use for the die is in the coating of textile filaments, especially small diameter filaments that are slubby.

Abstract: A variable-temperature pressure coating system for optical fibres, particularly for uv-curable primary coatings, includes a gas cylinder (8) for pressurizing a tank (1) of coating material, and a heat exchanger (15) controlling the temperature and thus the viscosity of the coating material supplied to a die chamber (19) through which an optical fibre (18) is passed following drawing. The temperature of the die chamber may also be controlled by the same circuit as the heat exchanger. A valve (14) serves to control flow to the die and to enable priming of the tube (13) by filling with coating material (and removal of air bubbles) prior to supply thereof to the die chamber (19). The system is designed for ease of operator handling together with production of high quality coatings at high speed.

Abstract: It comprises a receptacle containing a bath of molten silicon, the bottom of the receptacle includes a slot (7) through which there passes a tape (9) which is drawn vertically through the bath. The vertical wall of the slot (7) is downwardly flared, the horizontal section of the slot (7) includes a rectangular area (25) whose length is equal to the width of the tape (9) and two circular areas (28, 29) disposed at the two ends of the rectangular area (25), the diameter (32) of the circular areas (28, 29) being greater than the width of the rectangular area (25).Application to making solar photocells from silicon.

Abstract: Finish liquid is applied to a bundle of running filamentary material by running the bundle of filamentary material in monolayer form through a passage and conducting finish liquid under pressure through at least two side-by-side capillaries each having a diameter less than 0.06 inches. The finish liquid is discharged through outlet ends of the capillaries and onto the running monolayer of filamentary material. Preferably, the capillaries are separated by a divider wall which terminates short of the outlet ends of the capillaries, whereby those outlet ends define a slot through which the finish liquid is discharged. The slot preferably has end portions which are narrower than a center portion of the slot.

Abstract: An apparatus (30) for cooling a lightguide fiber (21) drawn from a molten portion of a glass preform (22) located in a furnace (23). The apparatus (30) has an upper chamber (34) and a lower chamber (36) each having a small opening in the lower portions thereof. The upper chamber (34) has a heat transfer liquid (35) therein and the lower chamber (36) is pressurized to prevent liquid from passing through the opening. The hot fiber (21) is cooled by the liquid as it is drawn through liquid (35) without physical contact with the periphery of the openings.

Abstract: An apparatus and method to saturate a fibrous web. The apparatus comprises a sealed chamber divided to form a low pressure preparation zone and a high pressure treatment zone. Air is evacuated from the open area between the fibers in the web in the vacuum zone and liquid in the treatment zone is forced into the evacuated open area between the fibers in the web. A pair of nip rollers are submerged in liquid in the treatment zone for squeezing residual air and liquid from the open area between the fibers in the web to cause liquid to be drawn into the open area between the fibers in the web upon exiting the nip between the rollers.

Abstract: An apparatus for applying a foamed treatment material such as size to a textile material such as threads as the latter passes between a pair of drive rollers includes a frame which forms a pocket for the size above the rollers with the rollers forming the bottom of the pocket. A guide projects down into the pocket toward the line of contact between the drive rollers and the threads pass through a passage in the guide so that the threads are shielded from the size in the passage and only the lengths of thread between the lower end of the guide and the drive rollers are exposed to the size. In order that the application of size to the threads is comparatively uniform, the guide is raised and lowered in response to the speed of travel of the threads so that longer lengths are exposed at faster speeds and shorter lengths are exposed at slower speeds.

Abstract: A lightguide fiber (21) which has been drawn from a preform in a furnace (26) and which has a relatively high temperature is cooled prior to its movement through an apparatus (41) which applies a coating to its outer surface. The fiber is cooled by moving it through a liquid material (42) in a reservoir (40) which is interposed between the furnace and the coating apparatus. The liquid material in the reservoir (40) is the same as the coating material contained in the apparatus that is used subsequently to coat the fiber.

Abstract: To uniformly coat a fiber, it is fed downwards through a passage filled with a coating fluid. The passage has a downwardly tapering lower zone into which fluid is directed from outside the passage uniformly, radially inwardly and downwardly. The fluid directed into the lower zone suppresses turbulence within the fluid at a bottom outlet aperture within the lower zone. The passage at an upper zone is large enough to allow bubbles to float to the surface of the fluid. The arrangement prevents turbulence and air bubbles from causing thinly coated fiber regions which might adversely affect the fiber integrity. The passage is defined by two relatively moveable bodies so that the rate at which the coating fluid is injected into the lower zone can be varied.

Abstract: A crucible containing molten silicon, has a strip of carbon film vertically transported through the melt, an optical system imaging a small area of the silicon surface onto a photodetector, said image area being that of the silicon liquid-solid interface, and a servo system connected to said photodetector and to an electrical drive for feeding silicon into said melt. The invention is applicable to the manufacture of solar cells.

Abstract: A method and apparatus for impregnating reinforcing fibers with a thermosetting resin having a short pot life. The method comprises mixing the components of the resin and supplying the mixed resin under pressure to an enclosed chamber. The reinforcing fibers are pulled through the chamber to rapidly impregnate the fibers with resin and the coated fibers are immediately utilized in forming a molded article.

Abstract: In an exemplary embodiment, tape-shaped silicon bodies for solar cells are formed by continuous coating of a carrier body having a mesh structure. A melt bath receives the silicon melt and has a floor part with capillary openings therein for supplying the melt, the capillary openings leading perpendicularly toward the exterior of the vat and proceeding parallel to one another, and wherein a channel for the guidance of the carrier body proceeding in a horizontal direction is disposed below the melt vat in the region of the capillary openings. The guide channel for the carrier body can also be disposed above a body with capillaries proceeding parallel in a vertical direction, the body being partially immersed in the vat containing the silicon melt for the purpose of supplying the melt via the capillaries. The devices enable continuous tape drawing from a silicon melt wherein convection currents are avoided in the melt.

Abstract: A process and apparatus for fabricating an optical fiber communication cable are described herein. The optical fiber cable has a cable core including a metal containment tube and at least one optical fiber within the tube. The containment tube preferably is formed by drawing a strip of metal through at least one forming die. In a first aspect of the present invention, smooth operation of the forming die is promoted by first passing the metal strip through a shaving die to remove any shearing burrs along the strip edges and to maintain the width of the strip within a desired tolerance.In a second aspect of the present invention, various approaches for effectively sealing the containment tube are described. In a first embodiment, the tube is sealed using a wave soldering approach wherein a flow of moving molten solder is used to substantially fill a seam in the tube.

Abstract: An apparatus and method effect application of molten size to textile yarns, such as spun yarns. An applicator cylinder is rotatable about a horizontal axis and has a number of grooves circumferentially formed in its surface, with peaked lands between the grooves, each land making an angle of about 8.degree.-12.degree. with respect to a plane bridging the top of an associated groove. A furnisher roll, also rotatable about a horizontal axis, picks up molten size from an open-top trough and delivers it to grooves in the rotating applicator cylinder. The surface of the furnisher roll cooperates with that of the applicator cylinder so that sloping areas of the furnisher roll mate with the lands of the applicator cylinder and so that flat areas of the furnisher roll bridge the entrances to the grooves. The furnisher roll may be of polytetrafluoroethylene machined to correspond to the surface of the applicator cylinder, or may have an elastomeric material surface.

Abstract: An improved coating apparatus including a paint vessel having an opening at its bottom for passing of an object to be coated therethrough, a sealing member disposed below the opening of said paint vessel and having an opening for passing of the coating object therethrough, a supporting section for supporting the paint vessel and a driving section for moving the paint vessel relative to the object to be coated. The sealing member has a brush to be in contact with the coating object passing through its opening and an elastic member provided exteriorly of the brush for pressing the brush against the object.

Abstract: An apparatus for applying a coating on a lightguide fiber (60). The apparatus is comprised of a container (10) having the coating die (18) in the bottom portion thereof and a plurality of separating means (26--26) therein which divides the container into an upper chamber (12), a lower chamber (16) and at least one chamber (14) intermediate to the upper and lower chambers. Each separating means (26) is sealed to the inner surface of the container (10) at the outer edge portion and has a small, centrally located aperture (28) which is vertically aligned with the apertures in the other separating means and the coating die (18). Additionally, a means is provided for directing coating material (40), under pressure, into the lower chamber (16).

Abstract: Methods and apparatuses are disclosed for coating elongated materials such as optical fibers wherein a shear force is developed by the elongated material moving through liquid coating material in a coating applicator of a magnitude such as to prevent the coating material from flooding the applicator.

Abstract: In the manufacture of optical fibres (18) these are coated as quickly as possible with a mechanical protection, suitably in the form of a coating of silicon rubber. The coating is provided by having the fibre pass through a bath (21) of coating material after drawing. As soon as the drawing rate exceeds a certain limit the applied coating becomes uneven. In accordance with the invention this limit can be substantially increased by placing a vibrating member (23), which is in contact with the bath surface, adjacent the point (27) where the fibre (18) passes into the bath (21).

Abstract: Vitreous optical fibers are useful in an expanding number of technologies. A process, corresponding apparatus, and a hermetically sealed fiber of the above nature are disclosed wherein high energy ionized plasmas are used in a continuous production of a coated vitreous optical fiber. Drawn fibers are axially aligned by ambient gases discharging through high vacuum gas locks. These fibers are then continuously fed through a high energy plasma zone so that the surface of the drawn fiber is subjected to ionized bombardment. This provides plasma-milling of the fiber surface for improving the fiber strength and for superior bonding of subsequently applied coatings.In preferred practice, a vacuum zone is used to deposit, from a plasma ion source, a diamond-like elemental carbon film onto the moving fiber. Another plasma vacuum zone may be used to deposit, over the carbon film, a very thin film of a conductive elemental metal illustratively; tin, indium and aluminum.

Abstract: Providing an electrical conductor with an insulation layer having a layer of dielectric carrier with magnetically permeable particles dispersed within the carrier, in which homogeneity is maintained in a fluid mixture of a fluid carrier and the particles, the conductor is moved vertically through a die means to coat it with a fluid layer of the mixture, the fluid carrier is dried and thickness of the dried insulation layer is controlled. This control is achieved by monitoring the thickness or diameter of the dried layer and, if a variation exists between the monitored and required values, the rate of fluid flow through the die means is adjusted to adjust the monitored values towards that required.

Abstract: A coating material is applied to drawn lightguide fiber in a manner which substantially prevents the inclusion of bubbles and which causes the fiber to be disposed substantially concentrically within the coating layer. The lightguide fiber is advanced through a continuum of coating material, which extends from a free surface of a reservoir and through two dies that are arranged in tandem, at a velocity which causes air to be entrained in the coating material. A pressure gradient is established between portions of the first die adjacent to its exit orifice. A first one of the dies communicates with the reservoir and the second die and further communicates at the interface of the dies with a pressurized supply of the coating material.

Abstract: A novel apparatus for manufacturing magnet wire in a continuous process by which coatings of a flowable resin material may be applied concentrically to a moving elongated filament in thickness of about 16 mils or less. The filament can be a bare copper or aluminum conductor having round or rectangular configuration or an insulated conductor upon which a top or an intermediate coat of material is desirably applied. Coatings of one-half mil and one mil also can be applied by the method of the invention. By the apparatus of the invention, magnet wire can be manufactured by continuously drawing the wire to size, annealing the wire, if necessary, insulating the wire with one or more coats of flowable resin material, curing the resin material, if necessary, hardening the resin material, and spooling the wire for shipment, without interruption at speeds limited only by the filament pay-off and take-up devices used.

Abstract: There is described a process for producing, in a continuous manner, a gradient dyeing across the width of a long strip of a plastic sheet and an apparatus used therefor. In a preferred embodiment of the invention, the orientation of the plastic strip is maintained substantially constant during the passage through a dye bath, and the dye liquid level is repetitively varied by use of a liquid level control means. This invention is particularly useful for making gradient-dyed plastic sheets which in turn are used for making sunglass lenses.

Abstract: An alloyed copper wire rod is formed by continuous rod-casting, wherein a core rod is driven through a crucible containing molten metal. High purity copper melt is continuously charged into the crucible; to which an alloying material is simultaneously added in a quantity which corresponds to the given casting speed of the core rod. The required alloy thus obtained is crystallized on the surface of the core-rod as it passes through the crucible and the rod produced is treated in the usual manner i.e., cooling, rolling and coiling.

Abstract: A device for depositing a layer of polycrystalline silicon on a carbon tape comprises a bath of molten silicon through which the carbon tape is drawn vertically. Two semicircular channels are supported vertically in the vicinity of the edges of the tape with their concave side towards the tape. The channels are partially immersed in the bath so as to raise the level of its surface by capillary action. The device is applicable to the manufacture of solar cells.

Abstract: In a method of insulating an electrical conductor, the conductor passes upwardly through a coating fluid and a die means which is carried in a vertical position by a supporting fluid force. This force is provided by the supporting force of the fluid or a magnetic force which holds the die in suspension. Freedom for horizontal movement of the die is provided to enable it to move in a manner corresponding to any lateral movement of the conductor, this die movement being controlled by hydrodynamic forces between conductor and die to maintain the concentricity of a fluid layer formed on the conductor.

Abstract: Apparatus for coating wire and the like includes a build control bar that projects horizontally, into the cloud chamber of an electrostatic fluidized bed coating unit, from a supporting carriage. The carriage permits facile movement of the control bar to vary its extension into the coating chamber, and means is provided thereon for changing the angular orientation of the bar by rotating it about its axis, to thereby dispose in working position any of a plurality of longitudinally extending different surface portions. The latter vary from one another in width dimensions and/or configuration, and thereby providing a masking member that can readily be adapted to correspond to the width and/or configuration of a workpiece.

Abstract: A nozzle structure for supplying synthetic resin to a core of a sheet molding apparatus for molding a sheet molding compound. The nozzle structure has a hollow annular nozzle with an opening directed generally along or at an angle to the core on which the sheet is being molded, and frustoconical members are provided for guiding linear materials through the nozzle structure for coating them with synthetic resin.

Abstract: A device for coating optical fibers with at least two coatings. The device comprises a holding block and at least three coating dies. The holding block has an outer surface with first and second ends, and an inner surface defining a channel extending from the first end to the second end. The coating dies are press fit into the channel, separated by resin chambers. The holding block is further provided with passages providing fluid communication between the resin chambers and the outer surfaces of the holding block.

Abstract: Apparatus for manufacturing a composite metal wire including a core metal wire having extruded therearound a coating metal layer which is different in material from the core metal wire. The coating metal is fed into a narrow passageway which is defined between a circumferential groove formed on the outer edge of a rotary wheel and a close fitting surface of a fixed shoe block, the cross-sectional area therebetween decreasing for half the distance between entry and discharge and thereafter increasing until discharge. The coating metal is carried towards an outlet end of the passageway by frictional drag with the surface of the passageway in accordance with the rotation of the wheel.

Abstract: An improved method for manufacturing a composite metal wire including a core metal wire having extruded therearound a coating metal layer which is different in material from the core metal wire, includes feeding the coating metal into a narrow passageway which is defined between a circumferential groove formed on the outer edge of a rotary wheel and a close fitting surface of a fixed shoe block, carrying the coating metal towards an outlet end of the passageway by frictional drag with the surface of the passageway in accordance with the rotation of the wheel, and passing a core metal wire harder in material than the coating metal through a covering chamber of a larger cross sectional area which is provided with a die and a nipple at the front and rear portions, respectively, whereby the core metal wire is covered with the coating metal in the covering chamber so that a predetermined construction of a composite metal wire is extruded through the die.