US2088446A - Method of producing covered wire - Google Patents

Description

July 27, 1937. H. G. SPECHT 2,088;446

METHOD OF PRODUCING COVERED WIRE Fi led Aug. 29, 1934 INVENTOR HHRRY B. EIFEEHT;

ATTORNEY.

Patented July 27, 1937 UNITED STATES PATENT OFFICE METHOD OF PRODUCING COVERED WIRE Application August 29, 1934, Serial No. 742,017

1 Claim.

The present invention relates to an improvement in covered wire and method of producing the same, an object being to produce a wire comprising a core of metal or other material 6 and a covering of a different material than the core, in a manner whereby the desired charac- "teristics of the covering material may be provided without respect to the characteristics of thecore, as distinguished from previous methods of 10 producing covered wire wherein the limitations of the materials of the core and covering had to be considered and compromised for, with the result that it was not always possible to obtain all of the desired characteristics in the core and covering. This was particularly true of small diameter covered wire such as silver solder covered wire, and other alloy coatings on hard and soft cores, as used in the formation of soldered seams in wire mesh fabric, and in the jewelry and other trades.

In making solder covered wires or in coating a core of one material with the shell of another material the methods heretofore employed consisted in rolling and drawing out a billet which had the covering material bonded about the core. One well-known process consists in turning up a core of material from one inch to six inches in diameter, placing this in a graphite or other suitable mold, and pouring the melted .30 covering material about the core and allowing it to solidify, binding the covering material to the core. The billet of combined metal is then taken from the mold and through a rolling, annealing and drawing process is reduced to the desired wire size. Another method consists in shrinking around a core a shell or tube of suitable bonding material, as for instance hard or soft solder, and then shrinking on top of this a shell or tube of the desired covering material. This three-piece billet is then heated to a temperature where the middle shell of bonding material will melt and form an intimate union between the cone and the outside shell. billet is then rolled and annealed and drawn into wire of the desired diameter. These methods are used both for producing very small diameter covered wire, and also in the making of copper and brass clad wire, and lead coated and other types of wires used in cable and electrical power lines. Obviously this continual rolling, annealing and drawing process is expensive and complicated, and has the further disadvantage that it does not permit of covering the core with materials that have a lower melting temperature than the annealing tem-,

This

perature of the core. This is because due to the rolling and drawing operations the material hardens and before it can be further processed, it must be annealed. If the melting temperature of the outside shell is below the annealing temperature of the core, the material cannot be annealed, and for this reason it has been impracticable to produce solder covered wire in which the solder had a relatively low melting point and in which the proper malleability and 0 ductility were maintained. It is also not possible to obtain uniformity in the covered wire produced by these methods, with the result that the covering may have thin and thick spots, the core is apt to be out of center, and the wire 15 is not of uniform cross-section.

According to the present invention I propose to first produce a core of wire of the proper temper and diameter desired in the finished wire, and produce separately a strand of covering metal or other material in the form of a fiat ribbon-like strip, which when rolled about the core will cover it. The core wire and covering wire are placed in juxtaposition and are first drawn through a die which bends the covering into U-form about the core, and then through other dies which close the covering over the core. In the case of a metal covering the seam of the covering may be fused, soldered, brazed or otherwise joined to produce a solid covering, and/or the covering may be bonded at its inner surface to the core, as by beating to a proper fusing temperature, or by interposing an intermediate bonding layer. By this process I can cover any core material with a shell of any covering material, regardless of the melting temperature of either the core or the shell, and the core will always be perfectly central and of uniform cross-section.

In the accompanying drawing, I have shown diagrammatically by way of example an apparatus for carrying out my invention.

Fig 1 is a longitudinal side elevation of an apparatus for producing metal covered wire, according to my invention.

Figs. 2 to 8 are enlarged sectional views taken along the lines 22 to 8-8 of Fig. 1.

Fig. 9 is a fragmentary side view of a modifled form of apparatus in which an intermediate layer is interposed between the flat strip and the core, and the two formed about the core together, according to an alternative method of carrying out my invention.

Fig. 10 is an enlarged sectional view taken along the line III-I0 of Fig. 9. 55

Fig. 11 is a fragmentary side view of a further modified form of apparatus and showing the method of laying in a solder strip, accord ing to an alternative method of carrying out my invention.

Fig. 12 is an enlarged sectional view taken along the line l2-l2 of Fig. 11.

Fig. 13 is a fragmentary side elevation of still another form of apparatus in which two layers are successively formed about the core, according to still another alternative method of carrying out my invention.

Figs. 14 to 18 are enlarged sectional views taken along the lines "-14 to i8-i3 of Fig. 13.

Fig. 19 is a side elevation of an apparatus for producing a covered wire according to my invention where the covering consists of other material than metal.

Referring to the drawing and particularly to Figs. 1 to 8, the core wire is designated as A and the covering strip, which may be of metal or any suitable material, is designated as B. This material may either be first prepared in the form of a fiat ribbon-like strip, or it may be fed into the machine in the form of a circular crosssection wire between a pair of rolls ill and II which are designed to flatten the wire to produce the ribbon-like strip of the proper dimensions. In this latter case the strip B will preferably be fed through an annealing unit i2 before being combined with the core. The covering material is fed through a feed roller [3 having a groove ll therein into which the material fits, and the core wire A is fed from a spool l5 beneath a roller 16 having a groove II to receive it and positioned above the roller l3 so that the core A is centrally imposed upon the covering strip B. From this point the core and covering strip are fed through the machine together, being first carried through a die ll, having an opening is therethrough, which is of a size to bend the covering strip into U-form about the core, as shown in Fig. 5. The wire then passes through a second die 20, having a passage 2| therethrough, and which is designed to partially close the covering material B about the core, as shown in Fig. 6. It then passes through another die 22, having a passage 23 therethrough, which brings the edges of the covering material into abutting relation, so that the core and covering material is now of circular cross-section as shown in Fig. '7. In passing through the dies the forming of the covering about the core is progressive and gradual, the die openings merely varying in diameter to accomplish this. The covered wire is drawn through the dies I3, 20 and 22 by means of a suitable capstan 24, and passes from this capstan through a sizing and finishing die 25, having an opening 26 therein, which is designed to produce the desired diameter of the finish wire, being drawn through this die by means of a capstan 21. Prior to passing through the die 25 the edges of the covering stripB are subjected to a melting or fusing'operation, so that as it passes through the sizing and finishing die the covering material is in the form of a continuous solid covering about the core. For the purpose of illustration I have shown a torch 28 directed against the seam at a point before 7 the covering wire passes through the die 25. It

will be understood that any suitable means for producing the desired melting or fusing operation may be employed. Due to the shaping of the covering, both through its transverse bending aboutthe core and through its being drawn through the finishing die 25, it is desirable to anneal it and for this purpose I have shown an annealing unit 29 between the capstan 21 and the spooling unit 30.

In Figs. 9 and 10 I have shown an alternative 6 manner of carrying out the invention by feeding a thin fiat strip of material C from a spool 31 between the core A and the covering material B, this strip being of a suitable bonding material as solder which will melt and form an intimate in union between the core and the outside shell, and between the edges of the covering material. The strips B and C are formed about the core in the same manner as the single strip B and prior to passing through the sizing and finishl5 ing die are subjected to a heating operation designed to melt the strip C. Instead of feeding in a separate strip C the covering strip 13 may be coated at one side with a layer of bonding material.

In Figs. 11 and 12 I have shown an alternative manner of securing the edges of the covering material. A strip of solder D, preferably of wedge-shape in cross-section, is fed between the edges of the covering material just as the wire 25 enters the die 22, the solder strip being fed from a suitable spool 32 beneath a grooved guide roller 33. In this case the covering material will be so dimensioned that when it is closed about the core a space is provided for receiving 30 the solder strip. The solder strip is thereupon melted or fused with the covering material by suitable means, as for instance the torch 23.

In Figs. 13 to 18 I have shown a further alternative form in which two layers are successively formed about the core, the intermediate layer E being of a suitable bonding material in the form of a fiat strip, and being first formed about the core as shown in Fig. 1. When thus formed the outside covering layer F, in the form of a flat strip, is formed about the core covered with the strip E being fed from a spool 34 between grooved guide rollers 35 and 33 and through dies 31, 38 and 33 corresponding in function to the dies ll, 20 and 22, as shown in Fig. 1, being drawn therethrough by means of a capstan 40. The covering layer F is reversely formed with respect to the intermediate layer E so that the seams are diametrically opposed. Before being drawn through the finishing die 23 the covered wire is subjected to a heating operation to melt the layer E and bond the covering to the core, and for this purpose I may employ an electric melting furnace 4| having a passage through which the wire moves continuously.

In Fig. 19 I have shown an apparatus for carrying out my invention where material otherthan metal is used as a covering, this material being designated as G. In the case of using a paper, fabric, or other similar covering the same may first be carried through a bath 42 of rosinous or other suitable material which will subsequently cement the covering to the core A. The covering material is formed about the core in the same manner as pointed out above, being drawn through the dies I3, 20 and 22 by means of a capstan 24. It may be coated with any suitable coating, as for instance an enamel coating, by passing it-through a bath 43, from which it passes through the sizing and finishing die 25, through which it is drawn by the capstan 21 before being wound upon the spooling unit 3.. The enamel or other coating may if desired be baked or heat treated, in which case I employ a suitable furnace through which the covered wire passes as it moves between the finishing die 25 and the capstan 21.

The covered wire produced as above outlined may according to my invention be re-processed by subsequent drawing and annealing operations, where it is desired to produce an extremely fine covered wire, as for instance of .002" in diameter. By this method a more uniform and accurate covered wire can be produced than has been heretofore possible where the wire was drawn down from a covered billet.

I have illustrated and described preferred and satisfactory forms of my invention, but it will be obvious that changes may be made therein, within the spirit and scope thereof, as defined in the appended claim.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:-

The process of producing covered wire which consists in simultaneously feeding between feeding rolls a flat covering strip, a fiat strip of bonding material, and a separate wire core in longitudinal juxtaposition, the fiat strip of bonding material being in engagement with said core, then feeding said strips and core through a succession of longitudinally spaced circular forming dies of gradually decreasing diameter to form the covering strip and bonding strip from fiat to tubular form about the core, the edges of the covering and bonding strips extending longitudinally of the core, and subjecting the covered wire to a heating operation at a point between the first and last dies to cause said bonding strip to bond the covering strip to the wire core.

HARRY G. SPECHT.

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