Method and apparatus for forming metal
US 2899728 A
Description (OCR text may contain errors)
Aug. 18, 1959 T. P. GIBBONS METHOD AND APPARATUS FOR FORMING METAL; FILAMENTS METHOD AND APPARATUS FOR FORMING METAL FILAMENT S Thomas P. Gibbons, Havertown, Pa., assignor, by mesne assignments, to Marvaland, Incorporated, Westminster, Md., a corporation of Maryland Application January 19, 1956, Serial No. 560,123
Claims. (Cl. 22-2001) The invention relates to means for collecting continuous metallic filaments, and particularly to apparatus for collecting one or more continuous metallic filaments concomitantly with their production.
In the United States patent application of Robert B. Pond, Serial Number 387,187, now Patent No. 2,825,- 108, issued Mar. 4, 1958, entitled Metallic Element and Method and Apparatus, filed on October 20, 1953, there is disclosed a method and apparatus for producing metallic filaments by impinging a stream of molten metal upon the open concave surface of a rapidly rotating chill block where it is cooled and centrifugally discharged into the area surrouding the chill block as a solidified filament. Additional inventive advancements in the field have been subsequently disclosed in the United States patent application, Apparatus and Method for Producing Metal Filaments, filed by Robert B. Pond, on December 23, 1955, Serial Number 555,085. In this latter application, the simultaneous production of a plurality of metallic filaments is accomplished by impinging a number of molten metal streams onto a single rotating chill block or onto individual chill blocks rotated by a common drive means. Both of these above-noted pending applications are primarily concerned with the actual production of the metallic filaments, as distinguished from the collection of the filaments once they have been formed, and therefore it is an object of the present invention to provide a new or generally improved and more satisfactory method and apparatus for collecting continuous metallic filaments.
Another object is the provision of method and apparatus for producing one or more continuous metallic filaments and collecting the same in a coiled form concomitantly with their formation.
Still another object is to provide an apparatus for the production of continuous metallic filaments in which both the chill block and the ejection tube or the collection trough or both are concomitantly rotated in the same direction to enable the solidified filament to collect in a coiled relationship.
A still further object is the provision of a metallic filament producing apparatus having a plurality of independent ejection tubes for continuously supplying streams of molten metal to a single rotating chill blocs, which ejection tubes are continuously supplied and may be in dividually operated and adjusted to vary the number and cross sectional shape of the filaments formed.
A still further object is to provide an apparatus which is simple in construction and use, readily adapted for large-scale production of filaments, and can be easily and economically fabricated from existing and available materials.
These and other objects and advantages of the invention will be apparent from the following description and accompanying drawing in which:
Figure 1 diagrammatically illustrates the filament producing and collection apparatus of the present invention; and
Figure 2 is a side view showing a modified arrangement by means of which a continuous supply of molten metal to the ejection tubes is obtained.
Generally, the invention relates to continuous metallic filaments which are produced by causing one or more streams of molten metal to be ejected through nozzles and be impinged against the open concave surface of a rapidly rotating chill block, where they solidify and are centrifugally discharged. The nozzles or an annular collection trough surrounding the chill block, or both, are rotated concomitantly with and in the same direction as the chill block, but at a reduced speed, so that the filaments once discharged from the chill block will coil themselves within the annular trough or container. The points of impingement of the molten metal streams against the chill block may be varied as desired by merely adjusting the positions of ejection tubes of the respective nozzles, thus enabling filaments of different, cross-sections to be formed. Two different arrangements are provided for continuously supplying the ejection tubes with molten material thereby facilitating the production of filaments of indefinite length.
The chill blocks employed in the apparatus of the present invention, as described hereinafter, are of the same general construction as those heretofore mentioned and more specifically described in the application noted above. Therefore, it will be understood that any reference made to a chill block in the following description is intended to read upon a chill block incorporating the same structural and functional characteristics as set forth in detail in said pending applications.
While the apparatus hereinafter described is suitable for use in producing and collecting extremely small elements or flakes which have a length to width ratio approaching unity, the invention is primarily concerned. with the collection of continuous filaments or filaments. having a considerable length, and therefore the ternr filament as employed throughout the description is intended to refer to an element having a substantial or indefinite length.
With reference to the drawing, there is described a chill block 7 having an open concave chill surface 9 against which the streams of molten metal are adapted to be impinged, and a central shaft 11 rotatably passing through the support 12 and adapted to be rotated by any suitable drive means, not shown. As mentioned in said pending application, the chill block 7 is movably rotated from ten to thirty thousand revolutions (r.p.m.), varying, of course, with the particular material being impinged thereon.
By means of a fixed structure, not shown, there is suspended a motor 13 having its drive shaft 15 extending vertically downward toward the center of the chill block 7. For purposes as hereinafter described, the motor 13, along with the elements carried thereby, is preferably mounted for vertical movement relative to its fixed supporting structure. In addition, any conventional means may be utilized to control the speed of the motor 13. A spider, including a hub 17 and a plurality of braced radiating arms 19, is adjustably secured to the motor shaft 15, as by a set screw 21, in a plane extending substantially at right angles to axis of the motor shaft. Each of the spider arms 19 is provided with a longitudinally extending opening into which is adjustably threaded an extension member 23. The extension members 23 each carry a nut 25 which is adapted to be threaded snugly against the outermost end of the respective spider arm 19 for locking the particular extension member in its radially adjusted position. The free end of each of the extension members 23 is shaped into a spherical socket 27 which snugly receives a correspondingly shaped ball 29 projecting laterally from the sidewall of an ejection tube 31. Together,
the ball 29 and socket 27 provide a conventional universal joint between the extension member 23 and ejection tube 31 which permits the ejection tube to be adjusted in planes extending both perpendicular to and axially of the extension member 23. If desired, in addition to the snugengagement between these parts, any suitable means, such as a set screw, may be utilized for holding the ball and socket in fixed adjusted position. The ejection tubes 31 are each of the same general construction as those described in the above-noted pendingapplications and include a nozzle 33 having a restricted orifice through which the molten material is extruded, and are preferably internally lined with a heatresistantmaterial, such' as silicon carbide.
The ejection tubes 31 are continuously supplied with molten metalthrough the conduit 35 connected to an annular chamber 37 fixed to the motor shaft 15. The conduit 35 is preferably flexible to permit the extension member 23' and the ejection tube itself to be easily adjusted asheretofore described. A stationary conduit 38 supplies the molten metal to the chamber 37 from any suitable source, not shown.
Encircling, the chill block 7, but being spaced there-- from, is an annular filament collection trough which may be of. integral construction and of a fixed depth or of sectional construction as shown in Figure 1 whereby the trough depth can be continuously increased as the collection of the finished filament progresses. The trough includes a bottom wall 39 and a pair of cylindrical sidewalls 48 and 41, the latter of which projects upwardly above the wall 40 and serves as an abutment surface against which the filaments are adapted to engage as they are discharged from the chill block. The wall 40 is releasably secured at its lower end to the annular frame 42 which is adapted to be rotated by any suitable means, not shown, and is provided, at spaced intervals along its outer periphery, with a plurality of vertical grooves 43, as for example dovetail grooves, within which the correspondingly shaped projections 44, along the inner periphery of the bottom wall 39, are adapted to be slidably guided. A plurality of annularly spaced pins 45 extend downwardly from the bottom wall 39 and pass through suitable openings in the frame 42, with any suitable means, such as compression springs 46, being interposed between the wall 39 and frame 42 to permit walls 39 and 41 of the collection trough to move relative to the wall 40. During normal operation of the apparatus, the collection trough is supported with the uppermost edge of its wall 49 even with or slightly below the adjacent top surface of the chill block so as to permit unobstructed travel of the filaments from the chill block to the collection chamben. As the collection trough receives the finished filament, the weight of the material collected causes the walls 39 and 41 to move downwardly so that the springs46 are compressed, and thus it is seen that production can continue until the walls 39 and 4-1 reach their lowermost position.
While springs 46 have been shown, it is of course possible.
to employ other means for positively lowering thewalls 39 and 41 without relying upon the weight of thesfilament collected.
Production and collection of metallic filaments with the structure described above is accomplished byv first.
placing an empty filament collection trough about the chill block '7, as shown on the drawing. The extension members 23 are adjusted relative to the arms 19 to position the ejection tubes 31 at the desired position radially of the chill block 7 and then locked in place by the nuts 25. Next, the ejection tubes 31' are moved, throughtheir universal connections, to aim the nozzles 33 toward the desired areas of the chill block. As more fully described in said pending application, Serial Number 387,187, the
closer the point of, impingement of the molten stream,
comes to the, center of the chill block 7, the thicker the resulting filament, 'while the angle of incidence which the Stream of molten metal forms with the chill surface 9 of the block 7 determines the angle of incidence of the departing filament. Fluid metal is admitted into the chamber 37 though the conduit 38 until a sufiicient head of molten metal is obtained. The head will, of course, depend upon the desired velocity at which the continuous molten metal streams are to be ejected from the tubes 31 and will accordingly vary. Satisfactory results have been obtained by ejecting the molten streams under a pressure of approximately three pounds, thus a relatively small column of molten metal in the chamber 37 is necessary.
Once these preliminary steps have been carried out, the drive motor for the shaft 11 is energized causing the chill block 7 to rotate as indicated by the arrow. Subsequently the ejection of molten metal from the tubes 31 is commenced and the shaft 15 is caused to rotate by the motor 13. The chill block 7 travels at a more rapid rate than the shaft 15 to prevent a pile-up of the molten stream at one point on the chill surface and to cause the metal, once solidified by contact with the surface 9, to be rapidly cast off by the centrifugal force generated by the rotating block and collected in coiled form as shown at 47. For example, the shaft 15 may be rotated at 800 r.p.m., while the chill block rotates at 15,000 r.p.m., thereby providing a relative velocity of 14,200 r.p.m. between these parts. Once the desired relative velocity between the shaft 15 and chill block has been obtained, for example by a series of trials, it must be maintained to insure proper filament production and collection. As the filament is received in the collection trough, the walls 39 and 41 are caused to move downwardly as heretofore described and thus production can continue without interruption until the walls 39 and 41 are at their lowermost position. Once the trough is filled, the motor 13 and the structure supported therefrom is elevated and the trough is removed from the annular frame 42 by releasing the lower portion of Wall- 40 therefrom and a new trough is substituted.
The size of the filaments produced will depend upon the ejection velocity of the molten metal and its temperature. Thus, the higher the temperature of the molten metal and the slower the ejection velocity, the thinner the filaments, as more fully explained in the copending application Serial Number 387,187. The concavity of the chill block enables each of the molten metal streams to strike the chill surface with a greater normal force causing the surface tension of the molten streams to break down at the points of impact and produce the intimate contact necesasry to enable the rapidly'rotating chill block to remove both the superheat and the latent heat of fusion and effect solidification. The filaments, once formed, travel along with the chill block through a small arcuate path and are then discharged therefrom along paths which lie in planes intermediate to similar planes extending tangentially and radially of the chill block, due to such factors as the centrifugal force developed by the chill block and the retarding air and friction forces.
While the ejection tubes have been described as being mounted for rotatable movement in the same direction as the chill block, but at a much slower rate, satisfactory filament production and collection can also be obtained by maintaining the ejection tubes stationary while the collection trough is caused to rotate concomitantly with the chill block rotation. Thus, the'collection trough may be rotated in the same direction as the chill block 7, but at a slower speed, to enable the filament discharged from the chill block to coil upon itself within the trough. It is evident that a combined movement of both the ejection tube and collection trough may be employed if desired.
Shown in Figure 2 is a modified arrangement for providing the ejection tubes 31 with a continuous supply of molten metal under pressure. In this construction there is provided a vertically disposed cylindrical chamber 49 which is supported from the fixed structure shown at 5'1 and 53 by the bearings 55 and 57. The upper bearing 55 encircles the chamber 49 while the lower bearing-'57 serves as a thrust bearing upon which rests the annular projection 59 formed integrally with the chamber wall. A stub shaft 61 depends from the lower end of the chamber 49 and carries a spider, consisting of hub 17 and arms 19 (shown in part), which in turn supports the ejection tubes in the same manner as heretofore described. Molten material under pressure is supplied to the chamber 49 through the conduit 63 from any suitable source, not shown, and is conveyed to the ejection tubes through the conduits 35 as noted above. A friction disk 65, fixed to the shaft 67 of the motor 69, engages with the external periphery of the cylindrical chamber 49 and is adapted to rotate the chamber about its vertical axis. Preferably, the outer wall of the cylindrical chamber 49 is coated, as shown at 71, with any suitable material, such as rubber, to insure that a good frictional engagement exists between the chamber wall and the friction disk 65. Since the conduit 63 remains stationary while the chamber 49 is rotated, a conventional slip joint is provided at 73 to prevent the loss of pressure. Utilizing the arrangement shown in Figure 2 in place of the corresponding structure shown in Figure 1 in no way alters the manner of production or collection of the filaments form that described above. However, this lastdescribed modification does enable an easier and a more reliable control of the pressure Within the chamber 49, and thus permits the production of a more uniform filament.
The apparatus thus described is adapted for use in producing filaments from various metals or alloys, such as tin, lead, cadmium, indium, zinc, bismuth, aluminum, magnesium, copper and their alloys, and the ferrous metals as a class as well as other metals and alloys.
From the above description of the invention, it is seen that the filaments are adapted to be collected in a neat compact coiled package concomitantly with their production and in an automatic manner. Further, the advantages resulting from the present invention in no way reduce the efficiency of the apparatus or its ability to form filaments of various lengths or cross-sections.
It is seen from the above description that the objects of the invention are well fulfilled by the method and structure described. The description is intended to be illustrative only and it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.
1. An apparatus for continuously casting and collecting continuous metal filaments including first means comprising a support, a chill block rotatably carried by said support and having a smooth, polished open concave surface, a driving mechanism for rotating said chill block, second means for impinging a stream of molten metal at an angle against the concave surface of said chill block, third means encircling said chill block in spaced relationship thereto, said third means serving as a collection container for the cast metal filaments, and means for imparting a rotary movement to both second means relative to said support.
2. An apparatus as set forth in claim 1 wherein said last-mentioned means rotates said second means at a speed slower than the rotation of said chill block.
3. An apparatus as set forth in claim 1 wherein said rotary movement of said second means is in the same direction as the rotation of said chill block and along a path concentric therewith.
4. An apparatus for continuously casting metal filaments including support means, a chill block rotatably carried by said support means and having a smooth polished open concave surface, a driving mechanism for rotating said chill block, a rotatable spider supported above said chill block, an ejection tube carried by said spider for impinging a stream of molten metal at an angle against the concave surface of said chill block, and means for rotating said spider in the same direction as said chill block but at a slower rate.
5. An apparatus as described in claim 4 wherein said means for rotating said spider includes a motor having a shaft to which said spider is fixed, and further including a chamber carried by the motor shaft, said chamber serving as a container into which the molten metal is fed, and means for conducting the molten metal from said chamber to said ejection tube.
6. An apparatus as described in claim 4 wherein said spider is carried by a cylindrical chamber mounted for rotatable movement, a conduit for supplying molten metal under pressure to said chamber, a slip joint between said conduit and said chamber to permit realtive movement therebetween without the loss of pressure, means for conducting the molten metal from said chamber to said ejection tube, and wherein said means for rotating said spider includes a friction disk engaging with the wall of said chamber and being driven by a motor.
7. An apparatus as described in claim 4 further including collection means encircling said chill in spaced relationship thereto and adapted to receive the cast metal filaments.
8. The method of casting and collecting metal filaments including the steps of impinging a stream of molten metal against a smooth polished open chill surface to solidify the metal, moving the surface about an axis relative to the stream as it is impinged thereon to centrifugally discharge the solidified filament therefrom, moving the stream of molten metal along an arcuate path about said axis of the chill surface, the movement of the stream of molten metal causing the point at which the stream of molten metal impinges against the chill surface to travel along the chill surface in a circular path concentric therewith so that the solidified filament is coiled about and outwardly of the chill surface as it is discharged therefrom.
9. A device for use in collecting metallic filaments including a first wall, a second wall disposed approximately parallel to said first wall and being spaced laterally therefrom, and a third wall extending between said first and second walls, one edge of said third wall being integrally connected with said first wall while its opposite edge is connected with said second wall for slidable movement in a vertical direction relative thereto.
10. An apparatus for continuously casting and collecting continuous metal filaments including, a chill block having a smooth polished open concave surface, means for rotating said chill block, means for impinging a stream of molten metal at an angle against the concave surface of said chill block, a collection container surrounding said chill block and concentric therewith, means for rotating said collection container with respect to the chill block to cause cast filaments formed on the chill block to be coiled in the collection container.
References Cited in the file of this patent UNITED STATES PATENTS 989,075 Staples Apr. 11, 1911 2,156,982 Harford et al May 2, 1939 2,621,914 Morgan Dec. 16, 1952 2,699,576 Golbry et al Jan. 18, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No- 2,899,728 August 18, 1959 Thomas P. Gibbons Itis hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected be'lowa In the grant, lines 2 and 12, and in the heading to the printed specification, line 5, name of assignee, each occurrence, for Marvaland, Incorporated" read Marvalaud, Incorporated column 5, line 59, for "both" read said Signed and sealed this 22nd day of March 1960.
KARL Ho MINE} ROBERT C. WATSON Attesting Officer Conmissioner of Patents