US2568303A - Apparatus for drawing wire - Google Patents

Description

P l951 A. H. ROSENTHAL 253,33 7

APPARATUS FOR DRAWING WIRE 2 sheets-sheet 1 Filed Oct. 4, 1944 mmvrm ADOLPH H. ROSENTHAL A T TOIQNEY ep 1951 A. H. ROSENTHAL APPARATUS FOR DRAWING WIRE 2 Sheets-Sheet 2 Filed Oct. 4, 1944 INVENTOR.

OLPH H. ROSENTHAL fifi I ATTOPNEY I AD BY Patented Sept. 18, 1951 APPARATUS FOR DRAWING WIRE Adolph H. Rosenthal, New York, N. Y., assignor to Scophony Corporation of America, New York," N. Y., a corporation of Delaware Application October 4, 1944, Serial No. 557,066

2 Claims. 1

This invention relates to apparatus for drawing'thin rods or wires of metal or metal alloy of any desired composition.

It is an object of the invention to increase the emciency of wire drawing apparatus heretofore used.

It is another objectof the invention to increase the speed at which a wire can be drawn through a given die or sets of dies in successive stages.

It is a further object of the invention to reduce the friction between a die and a wire drawn therethrough.

It is still another object of the invention to reduce the number of stages or draws in which a wire is shaped to the desired final diameter.

It is a further object of the invention to subject the wire while being drawn to mechanical working so as to increase its density, impart to it a desired structure and increase its tensile strength and ductility.

It is still a further object of the invention to give the wires a desired smooth finish and to remove therefrom undesirable coatings, such as oxide films.

It is still another object of the invention to produce a kind of self-cleaning action upon the hole of the drawing die and particularly upon a hole of very small diameter.

These and other objects of the invention will be more clearly understood when the specification proceeds with reference to the drawing in which Fig. 1 shows a vertical cross section through an apparatus embodying the invention utilizing magneto-striction effects, Fig. 2 a cross section along line 2-2 in Fig. 1, Fig. 3 a vertical cross section through a modification of that embodiment of the invention, Fig. 4 in vertical cross section and Fig. 5 in cross section along line 5-5 in Fig. 4 another embodiment of the invention utilizing piezo-electric effects.

According to the invention a die or dies through which athin rod or wire is drawn, is caused to vibrate mechanically at high, e. g. supersonic frequency in such a manner that an effective component in the direction of drawing results, and upon the longitudinal motion of the wire relative to the die is superimposed another relative motion of them in longitudinal direction and at supersonic or high frequency.

Referrin to the drawing, I0 is a tube of ferro magnetic material, such as nickel or nickel alloy,

e. g. a material known under the trade name "Invar or Monel metal which exhibts what is called a magneto-striction effect. Under the action of a magnetic flux varying at proper supersonic or high frequency recurrent dilatations and contractions of the tube in its longitudinal direction occur in that frequency, called its resonance frequency. If such a tube is mounted or rigidly supported at one place, an oscillating node exists there, whereas the freely projecting portion of the tube dilates and contracts recurrently, i. e. vibrates longitudinally, and the maximum amplitude of those dilatations and contractions occur at its free end if it is spaced from the mounted or supported place by ,4, W etc. wave length. The resonance frequency depends on the shape, dimensions and the material of the tube; the vibration amplitude depends on the value of the magnetic excitation, i. e. the maximum value of the total variation of the magnetic flux traversing the tube.

Tube I0 is mounted within a. ring surface [I of least longitudinal extension possible of a support constructed for instance like a bearing, comprisin a lower portion I2 and an upper cap l4 between which tube I0 is tightly clamped by means of screws l5, leaving a clearance l3 of preferably only a few thousandths of an inch between portion I2 and cap I4. Thus two portions of tube I 0 freely project from ring H to opposite sides, and preferably within the ends of each portion caps l6, I! are mounted provided with inwardly projecting rims l8, l9 forming abutments for wire drawing dies 20, 2|. Annular rings 22, 23 are screwed into the open ends oi. caps |6, H to firmly hold dies 20, 2| in position and to permit their exchange or replacement.

A coil each 24, 25 is positioned at the proper place around each projecting portion of tube I0, and their terminals 26, 21 are connected with a suitable source of electric oscillations the frequency of which can be adjusted within wide and advantageously supersonic range.

Generators, preferably tube circuits, such as the Hartley circuit, are well known in the art for producing oscillatory electric energy the frequency and amplitude of which and thereby the exciting energy supplied to coils 24, 25 can be adjusted in a purely electrical manner. Coils 24, 25 can be arranged in series or parallel with respect to such source, and in the latter case the oscillatory energy supplied to each coil regulated independently, or a separategenerator can be provided for each of the coils for instance if different frequencies and energies are intended to be supplied to them.

A wire is pulled through dies 20, 2| in the direction of arrows 29, so that the diameter or crosssectional area of wire portion 30 past die 2| il smaller than that of wire portion 28, and the diameter or cross-sectional area of wire portion 3,l is smaller than that of portion 30; the hole in die is correspondingly smaller than that of die 2|, which in turn is smaller in diameter or cross-sectional area than that of wire portion 28. Thus a two-stage reduction in diameter of wire 28 can be obtained in two draws and well known manner. Wire portion 28 can be heated, if so desired, before entering die 2| by well known means, such as a jet or jets of burning gas directed upon the wire. Wire portion 30 can be annealed, if necessary, by means and for purposes well known in the art of wire drawing.

While the wire passes die 2|, a magneto-striction effect of the nature described above is pro-' duced in the tube portion holding the die. To this end an oscillatory current adjusted to the frequency equalling the resonance frequency of tube I0 is supplied to electromagnet coil through terminals 21, whereby a magnetic flux changing its polarity in the frequency of the exciting current and of an intensity corresponding to the latters value is produced in said tube portion. As a result, longitudinal mechanical vibrations of the free end of the tube portion holding die 2| occur in the direction of double arrow 32, essentially parallel to the longitudinal extension of the wire pulled through die 2| and at high supersonic frequency, for instance 30,000 to 100,000 vibrations, or more, per second.

Let me consider now the effect of these mechanical vibrations of the die upon the wire moving therethrough during one vibration cycle; it will be appreciated that in the absence of those vibrations the die would have a certain stationary position from which it is moved upon excitation of the vibrations to the right and to the left each time to an outermost position. Now while swinging from its outermost position right to the outermost position left during a half vibration-cycle, the die moves in the same direction as the wire pulled therethrough; however, the average speed of this vibratory motion far exceeds that of the wire, and therefore the die overtakes the moving wire and exerts upon it a smoothing or polishing effect, because the part of .the wire upon which the die then glides has already been reduced in diameter. In swinging back from the outermost position left to the outermost position right under the next following, second half-cycle of its vibration, the die hits upon the not reduced portion 28 of the wire and effects the desired reduction of diameter. The resulting speed of the die relative to the wire during this second half-cycle equals the sum total of the absolute average speed of the die to the right due to its vibratory motion and the absolute speed of the wire pulled simultaneously to the left. Considering the high frequency of the vibrations, it will be appreciated that the resulting speed of the die relative to the wire is extremely high, of the order of a hammer stroke or higher, and consequently a similar result is obtained, viz. that the die during each vibration half-cycle to the right exerts upon the wire passing therethrough a very energetic swaging blow. The successive vibratory movements of the die to the right will result therefore in an intense swaging action upon all the successive portions of the wire drawn through die 2|.

Thus it will be appreciated that by the invention not only the usual effect of reduction in diameter will be obtained, but in addition thereto a smoothing or polishing effect upon a just reduced iortion of the wire (during the vibratory movement of the die from its outermost position left) alternating with an intense swaging action combined with a reducing in diameter action upon the wire portion just entering the die (during the vibratory movement of the latter in the opposite direction). By this swaging action, a desired orientation and shaping of the crystal fragments or grains, in particular elongation or size reduction of the grains, as thecase may be with hot or cold drawing, is effected, resulting in general in an increase of tensile strength and/or ductility of the wire. If the wire is preheated and by this or other reasons an oxide film formed on it in contact with the surrounding air, as is the case with almost all wire materials, this film will be mechanically removed by the hitting or swaging action of the die. If remainders of such film or other impurities on the outside of the wire, or a, lubricant are thus removed and accumulate in the hole of the die, they are stripped off during the vibratory movement of the latter to the left and a kind of self-cleaning of the die hole results.

The intensity of the hitting or swaging action can be adjusted by regulating the value or amplitude of the oscillatory current supplied to coil 25. However, it is also possible to adjust the frequency of the vibratory movement and thereby the effect of the hitting or swaging action of the die for instance by changing the frequency of the exciting current from the fundamental resonance frequency to an odd higher harmonic thereof, because the tube portion acted upon by the magnetic flux varying at such higher frequency is capable of vibrating at maximum amplitude also at a higher, odd harmonic frequency. If for any reason the desired hitting or swaging effect cannot be adjusted in either one or both the manners just described, either tube I0 is to be exchanged for another one, exhibiting the desired fundamental or harmonic resonance frequency, or the resonance frequency of tube I0 can be changed by fastening thereto at a proper distance from supporting surface ll an additional mass of proper value, for instance in form of a ring 33 indicated in dotted lines in Fig. 1 which can either be shrunk or removably fitted upon the outside of the tube. Instead, ring 23 could be exchanged for another one of larger or smaller mass, and/or die 2| exchanged for one of larger or smaller mass, or surface II which usually is of the least longitudinal extension, could be enlarged longitudinally so that the free length of the projecting portions of tube In is reduced.

By adjusting the hitting or swaging action not only orientation and/or elongation of the crystal grains or reduction of grain size and increase of tensile strength can be obtained, but also the ductility of the wire affected and in particular increased, for instance with fine tungsten and molybdenum wires. Since the die during its vibratory motion to the right also reduces the crosssectional area or diameter of the wire portion 28, the wire can be drawn at far greater speed through the die than heretofore and simultaneously the desired effect upon physical properties of the wire obtained. Since the vibratory movement of the die during each cycle or the amplitude of its vibration is very small, of the order of a few thousandths of an inch, and therefore correspondingly small portions of the wire are acted upon by each hit of the die, a larger reduction of diameter of the wire in one draw is possible than heretofore, without unduly straining the wire by an increased pull and detrimentally afl'ecting its structure. Thereby the number of draws for obtaining-a desired final smallest diameter can be reduced. The vibratory motion of .the die relative to the wire drawn therethrough also reduces the friction between the wire and the tool; thereby the emciency of drawing is increased.

The action of die upon wire portion II pulled therethrough is in principle the same as Just described with respect to die 2|. Again a smooth-.

ing or polishing and a hitting or swaging action combined with a drawing action is exerted by die 20 upon wire portions 3| and 30, respectively. The vibratory movement of die 20 and the energy of its action can be the same as, or different from that of die 2|. In the latter case either the value or amplitude of the exciting current supplied to coil 24 through terminals 26 can be made smaller or larger than that'for coil' or the left'projecting portion of tube Hi can or be made longer or shorter than the right projecting portion, or the farmer's mass can be changed in any manner described for the other portion of tube' 'lll hold-' ing die 2|. However, it should be understood that two draws eflected bya' single tube are only shown as an advantageous and most simple feature of the invention, and the latter can be used with all the effects and advantages stated for one die only; in such case-tube in projects from surface ll only to one side.

Whereas in Figs. 1 and 2 a tubular member of ferromagnetic material of the type herein concerned is shown, it should be understood that instead of a single tubular member two or more elongated members for supporting and mechanically vibrating a drawing die can be used, as shown in Fig. 3. In a support 34 provided with an aperture 35 through which the wire to be drawn is pulled to the left, two or more rod- like members 36, 31, which may be solid or tubular, of said particular ferromagnetic material are mounted and rigidly held by means of their screw-threaded ends 38, 39. Their opposite screw-threaded ends 40, 4| are passed with snug fit through bores in a die holder 44, for instance a disk provided with a tubular extension 45 screw-threaded on the outside upon which a cap 46 is screwed. A die 48 the outer surface of which tapers toward same as hereinbefore explained in more detail with respect to Figs. 1. 2.

Referring to Figs. 4 and 5, a support It includes a ring-shaped portion 54 into an annular recess 56 of which a steel plate 55 is fitted and held in position by the screwed in ring 51. A number of pieces 58 of equal ,dimension are arranged like a mosaic and cemented on one front face onto steel plate 55 and on their opposite front face onto a circular steel plate 59 provided with a die holder, e. g. a tubular extension 60 screw-threaded over part of its inside. A drawing die 6! is fitted into die holder 60 and held in position by ring 62 screwed intothe latter. Steel plates 5,. I9 are provided with aligned bores 83, 64 through which a wire drawn through die 6| in the direction of arrow 69 can pass.

Pieces 58 consist of piezo-electric crystal material, such as quartz, tourmaline, Rochelle salt. etc., of which it is known that they are capable of performing mechanical vibrations in the direction of a polar crystal axis under the actionof oscillating electrical energy applied on distant parallel surfaces perpendicular'to that polar axis. The polar axes of such crystals are ascertained by methods well known in the art, and preferably a plate of rectangular or square cross-section is cut from the crystal in such a manner that two parallel surfaces of the plate are perpendicular to the selected polar axis (Curie cut). If oscillating electric poteniials are applied to the cut piece on those parallel surfaces and the frequency of these oscillations equals substantially the resonance frequency of the cut piece, vehement vibrations of the latter in that resonance frequency are produced. The vibrations consist in recurrent support 34, is held in place by cap 46. Nuts 42,

43 are tightly screwed upon the ends 40, 4| and hold disk 44 in place. Coils 49, are slipped over rods 46, 41 and positioned at proper places. An exciting oscillatory current of adjustable supersonic frequency and energy is supplied in parallel and exact phase-coincidence to the coils through terminals 52 and the connecting conductors 5|; electrical means for individually adjusting the phases of the currents so supplied to the coils are well known and therefore omitted.

It will be understood that upon feeding oscillatory currents of equal value in full coincidence as to phase and frequency to the coils 49, 50, rods 36, 31 of equal dimensions and material will be caused by magneto-striction effects to vibrate longitudinally in unison the same way as a projecting portion of tube ill in the foregoing example; at the ends of rods 36, 31 facing support 34, an oscillation node will form, whereas the opposite ends of the rods in disk 44 will vibrate mechanically at equal maximum amplitudes and same, preferably supersonic frequency inunison, and these vibrations are translated through the disk upon die 48 while a wire is being pulled therethrough to the left. The operation and effect of this embodiment of the invention is otherwise the contractions and expansions of the piece in a direction perpendicular to these surfaces, so that the distance between the latter is recurrently reduced and increased; such vibrations are known as thickness vibrations of the piece. Instead of these thickness or longitudinal vibrations of the kind just described, transverse vibrations parallel to the planes can be produced and may be utilised; in the latter case, the length of the piece between the planes will periodically increase and decrease. However, for all pracLical purposes thickness vibrations are preferred.

The resonance frequency of a piece depends upon the crystal material from which it is cut and its dimensions; if other members of a different material are rigidly connected with the piece or several pieces to form a unitary element, the resonance frequency depends onthe thicknesses,

masses and sound velocities of the members.

Since the sound velocity of steel is practic'allythe same as that of quartz, a rigid combinaiion of quartz elements and steel members oscillates as one unit with a resonance frequency determined by the total thickness and shape of thecombined element.

The resonance curve of the oscillations of any such vibrator is extremely sharp, and it is therefore necessary that the frequency of the applied exciting electric vibrations equals or almost equals that resonance frequency, or that it 'is a harmonic, preferably odd harmonic thereof.

The energy of the mechanical vibrations thus excited depends on the energy of the applied electric oscillations and can therefore be regulated within wide range in an exclusively electric manner.

The pieces 58 are cut from such piezo-electric crystal material, preferably quartz, in such a manner that their surfaces contacting steel plates 55,

59 are parallel and perpendicular to a polar axis in the direction of which the cut piece is capable of thickness vibrations.

Oscillatory electric energy is applied to the opposite faces of the individual crystal pieces 59 by suitable electrodes; the steel plates 55, 59 are used inthis exemplifieation as such electrodes, and a terminal 66 is clamped to support 53 (which can be grounded, if necessary) and another terminal 61 to disk 59 which is electrically insulated from plate 55 and support 53 conductively connected therewith by the quartz pieces 58.

Upon application of oscillatory energy adjusted to a frequency hereinbefore defined to the terminals 69, 61, all the vibratory elements or pieces 58 will be excited to mechanical thickness vibrations in the direction of double arrow 59 which are translated upon disks 55, 59. In order to facilitate the mechanical vibration of steel plate 55 or to limit them essentially to a portion thereof equalling disk 59, a circular groove 65 or indentations over a circle of equal diameter can be provided, if so desired, on one or both sides of steel plate 55.

In operation, a wire is pulled through die in the direction of arrow 69 and simultaneously oscillatory electric energy supplied to the vibratory unit 55, 58, 59 through terminals 65, 61. Thereby disk 59, die holder 60 and drawing die 6| are caused to vibrate mechanically in the direction of double arrow 10 and essentially parallel to the direction of drawing the wire and the combined drawing and swaging effects described hereinbefore with reference to Fig. 1 are obtained.

The pull of the wire tends to press plate 59 upon the quartz pieces 58 and the latter upon steel plate 55 clamped in support 54, so that the cement connecting the quartz pieces and steel plates is subjected essentially to compression and strains are avoided which could loosen this connection.

It should be understood that instead of a combined vibratory unit of larger power as illustrated, of course a single, for instance cylindrical piece could be cut from a quartz crystal in such a manner that its opposite front faces are perpendicular to the polar axis of the crystal in which thickness vibrations can be produced, and a center bore made in the piece through which a wire can pass freely; such a single piece could be cemented between plates 55 and 59, or between any other suitable support and die holder.

By properly choosing the piezo-electric material and dimensions of the vibratory element or elements and of the other mass or masses, if any, rigidly coupled therewith, any desired resonance frequency, advantageously within supersonic range, can be obtained. A combined piece as illustrated and having a total thickness of the order of 5 or 10 mm., respectively, will exhibit a resonance frequency of the order of 600,000 to 300,000 vibration cycles per second. Again the vibratory energy displayed by an element or unit can be regulated in purely electrical manner by adjusting the amplitude and/or voltage and thereby energy of the exciting oscillatory current. Also the frequency can be adjusted by excitin a given vibratory element or unit at its 8 fundamental resonance frequency or higher harmonic thereof.

The material of the dies does not form a subject of the invention, and it should be understood that they can consist for instance of hardened steel, cemented tungsten carbide, or a diamond embedded in a matrix or proper metallic holder.

The invention is neither limited to any particular metal or metal alloy from which the wire is to be drawn, and is for instance applicable for drawing wires from iron and its alloys, steel, alloy steel, non-ferrous metals and their alloys, such as copper, bronze, aluminum and its alloys, nickel-chromium alloys, tungsten, molybdenum and their alloys.

' It should be further understood that the invention is not limited to any exemplification herein described and shown, but to be derived in its broadest aspects from the appended claims.

What I claim is:

1. In an apparatus for drawing wire, in combination, a rigid support, a tubular member of ferromagnetic material of the type which under the action of varying magnetic fluxes exhibits magneto-striction effects, said tubular member projecting from said support, a wire drawing. die holder mounted in said member spaced from said support, and electromagnetic means for producing in said tubular member magneto-striction effects to forcibly reciprocate its projecting end essentially in a direction parallel to that of drawing a wire.

2. In an apparatus for drawing wire, in combination, a tubular member of ferromagnetic material of the type which under the action of magnetic fluxes of alternating polarity exhibits magneto-striction effects and vibrates essentially in its longitudinal direction, a rigid support for said member at a place between and distant from its opposite ends, a holder for a wire drawing die mounted in each of said ends, and an electromagnetic coil each around and associated with each portion of said member on opposite sides of said support, each coil capable of being excited by oscillating electric currents to produce magnetic fluxes of alternating polarity through the associated portion of said member and thereby to cause it to vibrate longitudinally at its fundamental resonance frequency or an odd higher harmonic thereof.

ADOLPH H. ROSENTHAL.

REFERENCES CITED The following references are of record in the file ,of this patent:

UNITED STATES PATENTS I Date

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