US3841129A

US3841129A - Continuous, hydrostatic extrusion process and an apparatus using the same

Info

Publication number: US3841129A
Application number: US00341795A
Authority: US
Inventors: M Noguti; Y Yamaguchi; T Matsushita; M Nishihara; T Fujita
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 1972-03-17
Filing date: 1973-03-15
Publication date: 1974-10-15
Anticipated expiration: 1991-10-15
Also published as: FR2329368A1; JPS535266B2; FR2329368B1; JPS4895349A; DE2313323C3; BE796918A; DE2313323B2; GB1430623A; DE2313323A1

Abstract

A continuous, hydrostatic extrusion process and an apparatus therefor, wherein a stock wire is drawn through a die provided within the wall of a high pressure chamber and then force wound around a driven spool located within the chamber, after which the wire thus wound is extruded under a hydrostatic pressure through an extrusion die provided within another wall defining the chamber. Such apparatus thereby permits the continuous extrusion of a wire, i.e., the continuous feeding of a stockwire of a substantially unlimited length. In order to attain a greater percentage of reduction in cross-sectional area of the wire, heating means is provided within the chamber for heating the wire piror to extrusion. The apparatus further permits at least two stages of continuous drawing and extrusion of a stock wire by utilizing assembled units each of which incorporates the aforesaid features.

Description

United States Patent [1 1 Nishihara et al.

[451- Oct. 15, 1974 CONTINUOUS, HYDROSTATIC EXTRUSION PROCESS AND AN APPARATUS USING THE SAME [73] Assignee: Kobe Steel Limited, Kobe, Japan 22 Filed: Mar. 15,1973

21 Appl. No.: 341,795

[30] Foreign Application Priority Data Primary Examiner-Richard J. Herbst Attorney, Agent, or Firm-Oblon, Fisher, Spivak, McClelland & Maier 5 7 ABSTRACT A continuous, hydrostatic extrusion process and an apparatus therefor, wherein a stock wire is drawn through a die provided within the wall of a high pressure chamber and then force wound around a driven spool located within the chamber, after which the wire thus wound is extruded under a hydrostatic pressure through an extrusion die provided within another wall defining the chamber. Such apparatus thereby permits the continuous extrusion of a wire, i.e., the continuous feeding of a stockwire of a substantially unlimited length. In order to attain a greater percentage of reduction in cross-sectional area of the wire, heating means is provided within the chamber for heating the wire piror to extrusion. The apparatus further permits at least two stages of continuous drawing and extrusion of a stock wire by utilizing assembled units each of which incorporates the aforesaid features.

14 Claims, 8 Drawing Figures mimiuw' 1 14 snmuor 4 TOWARD 1 UP INE TA KE- MACH k FIG.6

CONTINUOUS, IIYDROSTATIC EXTRUSION PROCESS AND AN APPARATUS USING THE SAME BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a hydrostatic extrusion process and apparatus, and more particularly to a continuous hydrostatic extrusion process and apparatus wherein a stock wire is continuously extruded under a hydrostatic pressure.

2. Description of the Prior Art It is well known that a hydrostatic extrusion process enables the extrusion of a wire under a relatively lower extrusion pressure due to the reduced frictional losses and further permits the extrusion of a longer billet at a greater percentage of reduction in cross-sectional area of a wire, as compared with the conventional ram extrusion process.

However, the majority of such conventional hydrostatic extrusion processes are of the batch type, such that they necessitate repetition of the cycle of raising and lowering the pressure acting upon each billet. This results in various disadvantages, such as for example, great consumption of production time, fatigue problems encountered by various components of the apparatus, such as for example, the high pressure container, and the limited length of the wire produced, governed by the factors of billet length'and extrusion ratio. To overcome such shortcomings, various methods have been proposed, such as for example, feeding the stockwire continuously or intermittently. However, these have all proved to be unsatisfactory in actual industrial use due to the difficulties existing in the feeding step of the stock wire. The main reason for such failure, however, lies in the method of the approach in which such a stock wire is force fed into the high pressure chamber from a position exterior thereof.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved hydrostatic extrusion process and apparatus which can avoid such shortcomings by positively drawing a stock wire into the high pressure chamber and then extruding the same out of the chamber under a hydrostatic pressure, rather than by negatively pushing such a stock wire into the chamber from a position exterior thereto as has been proposed hitherto, whereby the stockwire can be drawn interiorly of the chamber in a substantially continuous manner-and then extruded therefrom.

Another object of the present invention is to provide an improved hydrostatic extrusion process and an apparatus, wherein a stock wire of a substantially unlimited length can be force fed or drawn through a drawing die into the high pressure chamber and then continuously extruded'through an extrusion die under a high hydrostatic pressure so. as to attain a cross-section commensurate with the shape of the opening of the extru sion die. v

A further object of the present invention is to provide an improved-hydrostatic extrusion process and an apparatus, wherein a stock wire of a substantially unlimited length can be force fed or drawn through a drawing die into a high pressure chamber and then continuously extruded through another die under a high hydrostatic pressure so as to attain a cross-section commensurate with the shape of the opening of the extrusion die, and wherein there is provided a heating means adapted to heat the stock wire prior to extrusion so as to thereby permit the continuous extrusion of the wire at a greater percentage of reduction in cross-sectional area.

A still further object of the-present invention is to provide an improved hydrostatic extrusion process and an apparatus, wherein a stock wire of a substantially unlimited length may be'force fed or drawn through a primary drawing die into a primary high pressure chamber, and then extruded under a high hydrostatic pressure existing within the chamber through a primary extrusion die so as to attain a cross-section commensurate with the shape of the opening of the primary extrusion die so as to thereby obtain a primary wire product, after which such primary wire product may be force fed or sion of a process and apparatus wherein a stock wire is force fed through a drawing die and into a high pressure chamber whereupon it is subsequently wound around a driven intermediate winding. means or spool, after which the wire 'thus wound may be extruded under a hydrostatic pressure through an extrusion die provided within the wall of the chamber and finally wound around a take-up means outside of the chamber.

The provision of heating means, which is adapted to heat the stock wire inside the chamber and prior to extrusion, further presents an advantage of a greater percentage of reduction in cross-sectional area of the wire. According to another aspect of the invention, such a cycle of drawing the stock .wire by utilizing the rotary motion of the driven spool and then extruding the wire under hydrostatic pressure through an extrusion die, can be used in stages to thereby enablean improved, continuous, hydrostatic extrusion of a wire.

BRIEF DESCRIPTION OF THE DRAWINGS Various other objects, features and'attendant advantages of the present invention will be more fully appreciated'as the same becomes better understood from the following detailed description when considered in connection with theaccompanying drawings, in which like reference characters designate like or corresponding parts throughout the several view s,,and whereini FIG. 1 is across-sectional view ofa continuous hydrostatic extrusion apparatus constructed according to the: present invention: and showing its cooperative FIG. 2 is a cross-sectional view of anio dified spool which may be utilized within the apparatus of FIG. I; FIGS 3, 4 and 5 are cross-sectional viewsof another embodimentof a continuous'hydrostaticextrusion apparatus constructed according to the present invention;

FIG. 6 is a schematic view of still another embodiment of a continuous, hydrostatic extrusion apparatus constructed according to the present invention;

FIG. 7 is a partial sectional view of a continuous hydrostatic extrusion apparatus constructed according to DETAILED DESCRIPTION OF Tl-IE PREFERRED EMBODIMENTS Referring now to the drawings, and more particularly to FIG. 1 thereof, the simplest embodiment of an apparatus embodying the principles of the present invention is disclosed as including a closed, cylindrical container 1 which defines a high pressure chamber which can withstand the high operational fluid pressure and which houses an intermediate winding means 'or spool 2 therein. The spool 2 is integral with a drive shaft 3 one end of which extends externally of the chamber 1 so as to be rotated by means of an appropriate power source at a predetermined R.P.M., and the drive shaft 3 is sealed in a liquid-tight manner relative to the wall of the high pressure chamber 1 by means of packings 4, 5 and 6, such that there is no likelihood of leakage of liquid therefrom under the high operational pressures. The axially outward force exerted by the fluid pressure acts upon the spool 2, and consequently, the spool 2 must positively rotate under such conditions. Accordingly, a thrust bearing 7 may be interposed between the wall of the high pressure chamber and the spool 2, or alternatively, the thrust bearing may be provided externally of the high pressure container whereby it is also able to receive the axial force caused by the high internal pressure.

A stock wire ,8 to be continuously introduced into the high pressure chamber from a position externally thereof is drawn through a radially aligned drawing die 9 provided within another wall of the high pressure chamber, whereby the wire of reduced diameter 11 is then wound upon the spool 2 in a spiral fashion. Substantially T-shaped fastening means 10 serves to guide the stock wire being fed as well as to rigidly mount the die 9 within thewall of the chamber 1, and the stock wire 8 is force-drawn through the die 9 into the high pressure chamber 1 by virtue of rotation of the spool 2, such procedure serving to-prevent-the leakage of the liquid which is contained within the chamber under high pressure. In this respect, as is knownwithin the field'dealing with the art of forced lubricated drawing of a wire, such as within a two-die system, the greater the percentage of reduction in cross-sectional area'of the wire at the drawing die and the greater the deformation resistance of the stock wire, then the greater the pressure that can be maintained upon the drawing side of the die. For example, within the range of the percentage of reduction in cross-sectional area of the wire at the die, of 2 to 5%, a pressure of approximately 600 kg/cm can be maintained for an aluminum wire of 0.2% yield strength of approximately 4 kg/mm'f, a pressure of approximately 2,500 kg/cm can be maintained for a copper wire of 0.2% yield strength of approximately 8 kg/mm and a pressure of approximately 8,000 kg/cm can be maintained for a steel wire having a yield strength of approximately 70 kg/mm The number of turns of the stock wire 11 to be wound upon the spool 2 should be such that the frictional force between the spool 2 and the wire 11 is greater than the force required for drawingthe stock wire 8 into the high pressure chamber, and ingeneral, such desired number of turns may be, for example, several turns. The wire which has been wound around -the spool 2 from its base to its tip in a manner so as not to cause any overlapping portion thereon may then be extruded to the atmosphere, through means of an axially aligned extrusion die 12 which is provided within the end wall of the high pressure chamber 1 which is opposite the wall in which drive shaft 3 is mounted, under a high hydrostatic pressure whereby the resulting extruded wire is of still smaller diameter. The wire thus extruded may then be wound by means of a suitable take-up machine which maintains the wire under tension. The extrusion die 12 is sealed within a cylindrical die receiving means 14 by means of suitable packing 13, and similarly, the die receiving means 14 is sealed relative to the high pressure chamber 1. In order to achieve'the desired extrusion, a liquid 15 under high pressure; produced by means of a suitable high pressure generating means, not shown, is introduced into the high-pressure chamber 1 through means of a radially extending high-pressure pipe 16 coupled to the high pressure chamber 1 by means of another substantially T-shaped fastening means 17.

The continuous, hydrostatic extrusion apparatus of the present invention thus includes means for drawing a stock wire 18 into the high pressure chamber 1 and subsequently winding'the same around a driven spool or intermediate'winding means, followed by the extrusion of the wire-out of the chamber 1 under hydrostatic pressure. This permits the use of a stock wire having a substantially unlimited length with the result of achieving a wire productalso of a substantially unlimited length.

In order to further appreciate the principles embodied within the present invention, let it be assumed that a stock wire in the form of a coilis housed within the high pressure chamber, without the use of the spool 2, both ends of the wire being introduced through dies 9 and 12, respectively, and that the pressure of the liquid 15 within the high pressure chamber 1 is gradually raised to a predetermined pressure whereupon the stock wire will be extruded through the dies 9 and Y12. However, as the resistance of the wire which is required to prevent extrusion through the drawing die 9 is smaller than-that of the wire at the extrusion die 12, the wire will in fact tend to be extruded through'the' die 9, and concomitantly therewith, drawing of the wire through die 9 will not'be'achieved, andconsequently, abr'eakdown within the extrusion process will occur.

' In contrast thereto, according to'the present invention, there is provided the spool 2 within the high pressure chamber 1 for winding the wire therearound asan intermediate step. As a result, if the frictional resistance .of the wire relative to-the spool2.is increased a substantial degree, extrusion of the wire 11 through the drawing 9 does not occur, whileextrusion of the vwire through the extrusion die 12 does occur thus permitting continuous extrusion of the wire. In order to assure such operation, there is further provided a wire supporting or pressing means 18 which serves to increase the frictional resistance of the wire 11 relative to the spool 2 thereby preventing the wire from being extruded back through the die 9. The pressing means 18 may be of the spring type, such as for example, a type which utilizes an arcuate plate or rotating roller springbiased against the spool 2.

Furthermore, as shown in FIG. 2, there may be disposed about the outer periphery of the spool 2 a cylinder 19 which is formed with a spiral, semi-circular groove within the inner peripheral surface thereof, the groove having a diameter substantially equal to that of the wire 11. The cylinder 19 is affixed to the body of the high pressure chamber 1, and consequently, the wire wound around the spool 2 may be fed from the entrance of the cylinder 19, through the spiral groove thereof, and out of an exit 20 such that the great frictional resistance produced between the spool 2 and the wire 11 may serve to prevent the wire 11 from being pushed back toward the die 9. It may be a common practice to use a liquid as the pressure medium withinthe high pressure chamber, but in such instance there may result a substantial frictional loss generated by means of the rotation of the spool therein. Accordingly, the viscosity of the pressure medium should be adjusted so as to minimize such frictional losses or alternatively, gas may be utilized as the pressure medium.

An experimental example utilized in connection with the embodiment of the present invention shown in FIG. 1 will now be described. An annealed copper wire was fed through the drawing die into the high pressure chamber. The stock wire was 2 mm in diameter with the percentage of reduction in cross-sectional'area of the wire at the drawing die 9 being 10%, the diameter of the wire wound around the spool within the high pressure chamber therefore being 1.8 mm. The pressure within the high pressure chamber was set at 2,500 kglcm and a die having an opening .of a diameter of 1.2 mm was utilized. In this respect, the drawing stress upon the product side was found to be 26 kg/mm with the result being the successful continuous drawing of a wire without experiencing any breakage. The percentage of reduction in cross-sectional area,'of the wire extruded from that of the stock wire was found to be 2.76% in terms of the extrusion ratio. The fact then that there can in fact be achieved such a continuous extrusion at such a great percentage of reduction in crosssectional area, per pass or extrusion, under a pressure of 2,500 kg/cm is an incomparable feature of the process and apparatus of the present invention.

As has been described hereinbefore, according to the embodiment shown in FIG. 1, a stock wire is initially wound around a spool located within the high pressure chamber and subsequently extruded to atmosphere. However, the pressure within the high pressure chamber is governed by the sealing'capability of the drawing die through which is drawn'the stock wire, and such a pressure is limited to approximately 600 kg/cm fora soft, pure aluminum wire, approximately 2,500 kg/cm for a copper wire, and approximately 8,000 kg/cm for a steel wire, thepressure thus varying with the types of wire materials used. Although the higher the pressure maintained the greater the flow stress of the stock materials, the percentage of reduction in cross-sectional area of a wire does not increase remarkably when the wire is extruded from the high pressure chamber to the atmosphere under such conditions. In addition, in utilizing a material having a small deformation resistance,

a high pressure cannot be maintained within the chamber, and consequently a considerably greater percentage of reduction in cross-sectional area of thewire at the time of extrusion cannot be achieved.

Under such circumstances, a second embodiment of the present invention, as shown in FIG. 3, may be utilized, wherein the stock wire is drawn into the high pressure chamber 1 at room temperature and subsequently heated to a predetermined temperature by means of a suitable heating means to thereby achieve a reduced deformation resistance, while effecting the extrusion at a greater percentage of reduction in crosssectional area of a wire, whereupon the wire may then be extruded from the high pressure chamber to atmosphere. The wire 11 which has been wound around the spool 2 is thus extruded out of the high pressure chamber through the axially aligned die 12 provided within one end wall of the high pressure chamber and wound by means of a take-up machine, not shown, under tension which is less than the yield strength of the wire product all being similar to the embodiment of FIG. 1, except that the wire 11 is also passed through an electric heating means 21 immediately before passing through the die 12. I

The electricity for use within the electric heating means 21 is fed through a terminal 24 and a lead wire 25 connected thereto, with the body of the high pressure chamber 1 serving as another electrode; The terminal 24 and the lead wire 25 are led through a suitable passage provided within a cylindrical die supporting means 29 which is similar to means 14, the terminal being anchored within a conically shaped aperture of means 29, and there being further provided insulating material 23 interposed thereb'etween. With this arrangement, electrical circuits may be completed between the rotating rollers'of the heating'means 21 and the die 12, and between the rotating rollers and the spool 2, respectively. Since the rollers are shortcircuited to the die 12, the electrical heating of the rollers may be effected. In this manner then, the wire 11 is heated to a desired temperature which softens the same and permits its passage through the die 12, with the result that aconsiderable decrease in the deformation resistance of the wire and av greater percentage of reduction in cross-sectional area of the wire in terms of a constant interior pressure existing within the high pressure chamber 1 can occur.

Surrounding the heating means 21 is an annular partition wall26 which further includes a heat insulating layer 27 which isprovided upon the inte'rior surface thereof so as'to surround the'heating means "21 and thereby minimize theheat loss within; such heating area. Since the sealing capability of the drawing 9 is de-' pendent upon the deformation resistance of the stock wire 8, it is preferable to increase the percentage of reduction ,in the cross-sectional area of the wire at the time of extrusion through the die 12 after the stock should be noted that the temperature which can be attained by utilizing the heating means 21 depends upon the magnitude of the electricity conducted through the terminal 24 and the lead wire 25 in addition to the properties of the pressure medium. If for example, an oil is used as the pressure medium, the temperature which can be attained will be within the range of from 200to 250C, and if a silicon oil is used, the temperature can be raised to approximately 350C. Furthermore, if argon or nitrogen gas is used as the pressure medium, a still higher temperature can be attained.

According to the previously described two embodiments of the continuous, hydrostatic pressure extrusion apparatus, therefore, a stock wire is drawn into a pressure chamber and subsequently wound around a driven spool, after which the wire is extruded to the atmosphere. The pressure within the high pressure chamber however is substantially proportional to the magnitude ofthe flow stress of the stock wire such that there results a limitation to the percentage of reduction in cross sectional area of the wire which is to be extruded out of the chamber. To avoid such a limitation, a third embodiment of the present invention, as shown in FIG. 4, may be utilized, in which the units such as have been referred to hereinbefore are combined or assembled in stages, whereby the pressures within the chambers are progressively raised per stage so as to achieve a greater percentage of reduction in cross-sectional area of the wire which is to be finally extruded to the atmosphere.

Referring now to FIG. 4, there is provided a first spool 102 disposed interiorly of a first high pressure container 101, spool 102 being integral with a first drive shaft 103 so as to rotate therewith at a given R.P.M. by means of a suitable drive means, not shown.

Seals

104, 105 and 106 are disposed about shaft 103 and serve to prevent the leakage of liquid from the high pressure container 101 out passed the shaft 103, while a first thrust bearing 107 is interposed between the spool 102 and end wall of container 101 so as to receive the axial force acting upon the spool 102.

A first stock wire 108 is drawn from a position exteriorly of the first container 101 through a radially aligned drawing die 109 of container 101 and then wound around the first intermediate winding means or spool 102, the forward end of wire 108 serving as a'second stock wire 111 which is similarly drawn'through a second radially aligned extrusion or drawing die 112 which is rigidly fixed within a 'side wall of a second high pressure container 119 by means'of a fastening device 114,

container 119 being concentric with container 101.

The wire 111 is then led into the high pressure container 119 whereupon it is wound around a second intermediate winding means or spool 120 which rotates within the container 119. The pressure of the liquid 115 within the first high pressure container 101 is ini-.

tially raised. to a predetermined value by means of a high pressure generating means, not shown, located exteriorly of the container 101 and is then fed into con tainer 101 through means of a radially extending pipe 116 which is disposed within a side wall of container 101/1n addition, a first pressing plate 118 is also provided within container 101 so as to effectively produce the desired frictional force between the first spool 102 and the second stock wire 111.

The rotation of the first spool 102 is transmitted via a first gear mechanism 121 to a second drive shaft 122 so as to thereby effect the rotation of the second intermediate winding means or spool 120. It should he noted, however, that the gear mechanism 121 should be such that the rotational speed of the spool 120 be greater than that of the spool 102, and that the ratio of the rotational speeds of the spools 120 and 102 be governed by the percentage of reduction in cross-sectional area of the wire 111 passing through the die 112. A cover 123 is interposed between the gear mechanism 121 and the stock wire 111 so as to prevent any interference or binding therebetween, and a seal 124 serves to prevent any leakage of pressurized liquid from the container 119 out passed the drive shaft 122.

The pressure P of liquid 115 disposed within the first high pressure container 101 is dependent mainly upon the sealing capability of the die through which the stock wire 108 is being drawn, while, in general, there can be maintained a pressure which exceeds the value corresponding to the yield strength of the wire. Naturally, the same principle applies to the die 112 such that it is possible to raise the pressure P of liquid 128 within the second container 119 to a value greater than the pressure P, within the first container 101 by approximately 1,000 kg/cm for a work-hardened aluminum wire, and approximately 3,000 kg/cm for a workhardened copper wire, such pressure being attained by means of a high pressure generating means, not shown, located exteriorly of container 1 19 and which conducts the liquid through a radial passage 127 which is provided within a side wall of container 119. As is the case with the first spool'l02, there 'is provided a pressing plate 125 associated with the second spool 120 such that the third stock wire 126 wound around the spool 120 may not be subjected to any slippage whatever.

Subsequently, the third stock wire 126 within the second container 119 passes through a third radially aligned extrusion or drawing die 129 to be wound around a third intermediate winding means or spool 131 located within a third high pressure container 130 which is also concentric with

containers

101 and 119. A pressing plate 139 is provided for the third spool 131 so as to minimize the slippage between such spool and the stock wire 126, and the rotation of the third spool 131 is effected by means of the rotation of the second spool 120 the rotary motion of which is transmitted via a second gearmechanism 132 and a third drive shaft 133 such that the ratio of the rotational speeds of the spools should accommodate the percentage of reduction in cross-sectional area of the wire at the die 129. Sealing between the drive shaft 133 and the container 130 is effected bymeans of suitable packing rings 134.

The pressure-P of the liquid 135 disposed within the third container 130is greater than the pressure P of the liquid 128 within container 119, the pressure of. the liquid 135 being raised to the predetermined pressure P by means of a high pressure generating means, not shown, disposed exteriorly of the container whereupon the liquid may be fed through a radialpassage 136 which extends through a side wall of container 130,. In this manner, the stock wire 137 may in turn be wound around the three spools 102,120, and'131'and then extruded througha fourth axially aligned extrusion die 138 to the atmosphere to form a final wire product 148. It should be noted that, when extrusion and drawing operations are used in combination while winding the final wire product 148 upon suitable take-up machinery to thereby cause a predetermined amount of tension therein, a still greater percentage of reduction in cross-sectional area of the wire can be achieved with the resultant stable process. Provided between any two of the stepped containers housed in assembly are packings 140 and 141 which prevent the leakage of pressurized liquid therefrom. In addition to such sealing means, there is also provided a packing ring 142 which is interposed between the container 130 and the fourth die receiving means 144 which similarly prevents any fluid leakage therefrom, the die receiving means 144 being retained within container 130 by means of. a receiving plate 149.

Heating means 143 are also provided to heat the stock wire 137 prior to such wire being drawn through the fourth die 138, and it is recommended that such electrical heating means be used for a wire having a smaller gauge, whereby the electricity may be fed to the heating means 143 through means of an electrode 145 which is mounted within the die receiving means 144, and 'a lead wire 147. An insulating body 146 is interposed between electrode 145 and receiving means 144, and consequently the stock wire 137 may be heated and subsequently drawn through the .die 138 so as to experience a greater percentage of reduction in cross-sectional area. Rollers 149 serve as a guide means for the stock wire 137 entering the vicinity of heating means 143, thereby enhancing the electrical heating effect, and in addition, there is also provided a substantially annular partition wall 150 for defining the heating zone, an insulating material 151 being provided upon the inner surface of wall 150 so as to improve the heat insulation.

The third embodiment shown in FIG. 4 is thus directed to a combination of units, wherein, for each unit, there is provided an intermediate winding means within a high pressure chamber and a stock wire is able to be continuously drawn into the chamber by rotation of the winding means, after which that end of the wire thus wound is extruded out of the chamber. The embodiment is characterized by the fact that such units are assembled so as to form a multi-stage construction in which there exists differences in fluid pressure between the container of the first stage and the container of the second stage, and between the container of the second stage and the container of the third stage, whereby it is possible to continuously extrude and draw the stock wire under a high pressure. Such embodiment is further characterized by the fact that at least one heating means is provided as required to thereby achieve a greater percentage of reduction in crosssectional area of the wire at the time of extrusion.

The principal object of this embodiment is attained when the fluid pressures P P and P within the

respective containers

101, 119 and 130 are predetermined according to the following relationship:

P P P whereby the stock wire may be extruded to the atmosphere within the final stage having the inner pressure material under a high pressure and in preventing defects such as cracking and the like.

While the inner pressures P P and P are generated by a high pressure generating means located exteriorly of the respective containers, they are of a nature which depends upon the working conditions of the wire. More specifically, in instances where the differences between P and P and P -and P are assumed constant or the ratios between P and P and P and P are constant, it is possible that the required supply of pressurized fluid can be attained by one one pressure generating means. However, in the instance where P P and P are required to be adjusted independently, then there should be provided respective pressure generating sources.

In general, while it is recommended that a liquid be used as the pressure medium, care should be taken due to the fact that the viscosity of the liquid will increase with an increase in the inner pressure thus causing frictional losses due to the rotation of the spool and/or gear mechanisms. Accordingly, it is desirable to use a mixture of glycerin and water or light oil as the-pressure medium, whereby .the viscosity is relatively smaller under high pressures. Naturally, it may be possible to use various kinds of vegetable or mineral oils for the lower pressure range, or otherwise, it may be possible to use a high-pressure gas, as the case may be.

Although the embodiment describedv comprises a combination of three high pressure chambers, any multi-stage construction, suchas for example, those apparatus utilizing two, four, orfive stagescan be used, and despite the possible advantage of achieving a substantially greater percentage of reduction in the crosssectional area of the'wire, the construction of such a system would be rather complex.

To continue further, in the instance where hotextrusion is accomplished within the apparatus disclosed, there arises the necessity to provide water cooling means, such as forexample, water jackets, so as to preclude a dangerous temperature rise due to the heat produced by agitating the pressure mediums. Such is true evenin the case of cold extrusion, due. to the heat generated by the deformation process occurring at the die portions and due to the frictional heat of the rotating partswhich is especially critical at the seal locations. I

The apparatus described thus far also suffer from the disadvantage that 'theaxial forceproducedupon the spools must'be receivediby means of the thrust bear-. ings. However, such disadvantage can be avoided by the provision of the embodiment shown in FIG. 5, whereinthe running direction of the stockwire is substantially, in the axial direction of a container 1 and there is provided a pair of bearings 7a and'7b within the walls of the container 1 for mounting a spool driveshaft '3. The shaft 3 extends through radially extending holes with in the upper and lower walls of the container 1 and serves to mount a spool 2, the bearings 7a and 7b being anchored within the recessed portions associated with the holes through which shaft 3passe s. Packing rings 4 and 5 are interposed between the bearings'7a and 7b, and the container 1, respectively whereby fluid leakage between the shaft 3and container 1 is prevented One end of the shaft 3 is adapted to be rotated at a predeter mined'R.P.M. by means of a suitable drive source, not shown.

In operation, the stock wire 8 is drawn into the con tainer 1 through an axially aligned die 9 rigidly fixed within one end of the container 1 by means of fastening means 10, and then wound around the outer periphery of the spool 2 after which the wire 8 is extruded to the atmosphere under hydrostatic pressure through another axially aligned die 12 which is rigidly mounted within the other end of the container by means of another fastening means 14. The pressure medium is fed from an exterior pressure source through a radially extending high pressure pipe 16 communicating with a radial passageway provided within the wall of the container 1 and is adjusted to a proper pressure value P. Consequently, with the arrangement as shown in FIG. 5, while it may not be wholly advantageous, in all respects, for the container 1 to be provided with radial apertures which are adapted to receive therein the

bearings

70 and 7b for mounting the shaft 3, the predominant advantage attained is that the axial force produced upon the spool 2 can be eliminated.

In addition, the embodiment shown in FIG. 6 permits a plurality of units as shown in FIG. to be assembled in an axial direction, in which the R.P.M. of

shafts

3a, 3b and 30 within the containers la, 1b, and 1c can be externally and independently adjusted.

Referring now to FIG. 7, a further embodiment of the present invention is shown wherein a stock wire 301 is conducted into the high pressure chamber 300 through means of appropriate sealing means which includes 0- rings 304 and V-shaped packing 305, the drawing die having been eliminated. The wire 301 is further guided through an axial passageway within tightening means 302 which also serves to maintain the sealing means in proper relation to chamber 300 whereby the wire 301 may be introduced into the chamber 300 in fluid-tight fashion. Although it is thus seen that the drawing die may be replaced by suitable sealing means so as to nevertheless introduce the stock wire into the high pressure chamber in fluid-tight condition, for the purpose of obtaining a higher reduction in the cross-sectional area of the workpiece, the sealing member may preferably in turn be replaced by the drawing die through which means the sealing function is similarly attained.

Turning now to FIG. 8, still another embodiment of the present invention is disclosed wherein the high pressure chamber 200 has an axially rotating shaft 201 disposed therein, the ends of which are supported within cap screws 202 which in turn have, at their inner portions, recess means for housing sealing means 203. A high pressure fluid 204, which is produced by means ofa high pressure generating source, not shown, may be introduced into chamber 200 through means of a radially extending high pressure pipe 206 whichis secured relative to chamber 200 by substantially T- shaped fastening 'means 205. The stock wire 207, is thus charged into the high pressure chamber200 through means of the radially extending sealing member or drawing die 208 whereupon it is subsequently wound about shaft 201 which is rotated by suitable driving means, not shown, and finally extruded through a radially extending extrusion die 209 under the influence of the hydrostatic pressure, die 209 being laterally offset relative to drawing die 208.

Obviously, many modifications and variations of the present invention-are possible in light of the above teachings. It is to be understood therefore that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A continuous, hydrostatic extrusion process, characterized in that said process comprises the steps of:

continuously charging a stock wire into a high pressure chamber through sealing means by utilizing the continuous winding action of an intermediate winding means provided within said high pressure chamber; continuously winding said charged stock wire around said intermediate winding means; and

continuously extruding said wound stock wire out of said chamber through an extrusion die under the influence of a hydrostatic pressure maintained within said chamber.

2. A continuous, hydrostatic extrusion process as set forth in claim 1, wherein said stock wire is heated prior to said extrusion.

3. A continuous, hydrostatic extrusion process, characterized in that said process comprises at least two sequential stages each of which comprises:

continuously charging a stock wire into a high pressure chamber through sealing means by utilizing the continuous winding action of an intermediate winding means provided within said high pressure chamber;

continuously winding said charged stock wire around said intermediate winding means; and

continuously extruding said wound stock wire out of said chamber and into said high pressure chamber of the subsequent stage through an extrusion die under the influence of a hydrostatic pressure;

whereby said wire will be continuously extruded from one of said stagesto another and ultimately extrudedto the atmosphere under the influence of said hydrostatic pressure through an extrusion die within the final one of said stages.

4. A continuous, hydrostatic extrusion process as set forth in claim 3, wherein said stock wire is heated within at least one of said stages prior to said extrusion of said wire through one of said extrusion dies.

5. A continuous, hydrostatic extrusion apparatus comprising:

a high pressure chamber adapted to maintain a hydrostatic pressure medium therein;

an intermediate winding means provided within said chamber for continuously winding a stock wire therearound; r sealing means adapted to' charge said stock wire into said high pressure chamber and conduct said wire tosaid winding means under the influence of the continuous rotary motion of said winding means;

' and an extrusion die adapted to extrude said wound wire from said high pressure chamber under the influence of 'said'hydrostatic pressureL 6. A continuous,'hydrostatic extrusion apparatus as set forth'in claim 5', wherein said apparatus further comprises a heating means provided within said high pressure chamber and adapted to heat said stock wire prior to said extrusion of said wire through said extrusion die.

7. A continuous, hydrostatic extrusion apparatus, characterized in that said apparatus includes at least two stages each unit or stage of which comprises:

a high pressure chamber adapted to maintain a hydrostatic pressure medium therein; I

an intermediate winding means provided within said chamber for continuously winding a stock wire therearound;

sealing means adapted to charge said stock wire therethrough and into said high pressure chamber and conduct said wire to said winding means under the influence of the continuous rotary motion of said winding means; and

an extrusion die adapted to extrude said wound wire from said high pressure chamber under the influence of said hydrostatic pressure, whereby said stock wire is charged through said sealing means by means of said intermediate winding means within one of said stages and is extruded through said extrusion die of said one of said stages so as to be conducted through a successing stage and ultimately be extruded to atmosphere through said extrusion die of the final one of said stages under the influence of said hydrostatic pressure.

8. A continuous, hydrostatic extrusion apparatus, as set forth in claim 7, wherein said apparatus further comprises a heating means provided within at least one of said high pressure chamber for heating said stock wire prior to said extrusion of said wire extrusion die.

9. A continuous, hydrostatic extrusion apparatus as set forth in claim 7, wherein said extrusion die of one of said stages serves as said sealing means of a succeeding one of said stages.

10. A continuous, hydrostatic extrusion process as set forth in claim I, wherein said sealing means is a drawing die whereby said stock wire may be continuously force drawn into said high pressure chamber through said drawing die.

11. A continuous, hydrostatic extrusion process as set forth in claim 3, wherein said sealing means is a drawing die whereby said stock wire may be continuously force drawn into said high pressure chamber through said drawing die.

12. A continuous, hydrostatic extrusion apparatus as set forth in claim 5, wherein said sealing means is a drawing die adapted to draw said stock wire into said high pressure chamber.

13. A continuous, hydrostatic extrusion apparatus as set forth in claim 7, wherein said sealing means is a drawing die adapted to draw said stock wire into said high pressure chamber.

14. A continuous, hydrostatic extrusion apparatus as set forth in claim 9, wherein said sealing means is a drawing die adapted to draw said stock wire into one of said succeeding stages.

Claims

1. A continuous, hydrostatic extrusion process, characterized in that said process comprises the steps of: continuously charging a stock wire into a high pressure chamber through sealing means by utilizing the continuous winding action of an intermediate winding means provided within said high pressure chamber; continuously winding said charged stock wire around said intermediate winding means; and continuously extruding said wound stock wire out of said chamber through an extrusion die under the influence of a hydrostatic pressure maintained within said chamber.

3. A continuous, hydrostatic extrusion process, characterized in that said process comprises at least two sequential stages each of which comprises: continuously charging a stock wire into a high pressure chamber through sealing means by utilizing the continuous winding action of an intermediate winding means provided within said high pressure chamber; continuously winding said charged stock wire around said intermediate winding means; and continuously extruding said wound stock wire out of said chamber and into said high pressure chamber of the subsequent stage through an extrusion die under the influence of a hydrostatic pressure; whereby said wire will be continuously extruded from one of said stages to another and ultimately extruded to the atmosphere under the influence of said hydrostatic pressure through an extrusion die within the final one of said stages.

5. A continuous, hydrostatic extrusion apparatus comprising: a high pressure chamber adapted to maintain a hydrostatic pressure medium therein; an intermediate winding means provided within said chamber for continuously winding a stock wire therearound; sealing means adapted to charge said stock wire into said high pressure chamber and conduct said wire to said winding means under the influence of the continuous rotary motion of said winding means; and an extrusion die adapted to extrude said wound wire from said high pressure chamber under the influence of said hydrostatic pressure.

6. A continuous, hydrostatic extrusion apparatus as set forth in claim 5, wherein said apparatus further comprises a heating means provided within said high pressure chamber and adapted to heat said stock wire prior to said extrusion of said wire through said extrusion die.

7. A continuous, hydrostatic extrusion apparatus, characterized in that said apparatus includes at least two stages each unit or stage of which comprises: a high pressure chamber adapted to maintain a hydrostatic pressure medium therein; an intermediate winding means provided within said chamber for continuously winding a stock wire therearound; sealing means adapted to charge said stock wire therethrough and into said high pressure chamber and conduct said wire to said winding means under the influence of the continuous rotary motion of said winding means; and an extrusion die adapted to extrude said wound wire from said high pressure chamber under the influence of said hydrostatic pressure, whereby said stock wire is charged through said sealing means by means of said intermediate winding means within one of said stages and is extruded through said extrusion die of said one of said stages so as to be conducted through a successing stage and ultimately be extruded to atmosphere through said extrusion die of the final one of said stages under the influence of said hydrostatic pressure.

10. A continuous, hydrostatic extrusion process as set forth in claim 1, wherein said sealing means is a drawing die whereby said stock wire may be continuously force drawn into said high pressure chamber through said drawing die.