US2176365A - Extrusion mill - Google Patents

Description

2 sheds-sheet 1v EXTRUS ION MILL Oct. 17, 1939. c. D. sKlNNER E1- AL l Filed March 12, 1937 Oct. 17, 1939. c:.,| sKlNNER Erm. f 2,176,365

EXTRUSION MILL -Filed March l2, 1937 2 Sheets-Sheet 2 .20

Patented oeeflv, v1939 'PATENT EXTRUSION MILL Application March 12, 1937, Serial No. 130,569

l e claims'. Our invention relates to the manufacture oi extruded `articles, and particularly to the manulc the extruded articles leaving the press, and in method.

Our objects are to reduce the sire and cost of an extrusion mill of given capacity; to minimize the cost oi' handling material within the mill;

i@ to economize in labor; to reduce scrap loss; and

to produce superior product. An extrusion mill embodying the invention is illustrated in the accompanying drawings. Fig. I is a fragmentary view of the mill in vertical w section; Fis. E is adiagrammatic door plan of the mill; and Fig. lII is a fragmentary view on the plane of section of Fig. I, showing particular portions of the mill to larger scale.

Y Referring to the drawings, we provide a mill having upper and lower working stages A and B, separated by a horizontal oor or platform C. Une ormore tower presses 2 are installed in the upper stage, and in accordance with known practice each press includes an extrusion cylinder 2i)v 30 secured upon a bed or platen 4I that embodies .extrusion dies 22 in a locking plate or stripper 2| (Fig. UI) Billets of aluminum (or of 'other metal to be extruded) are introduced to the extrusion cylinder one after another and at extru- 35 sion temperature; in known way the vertically reciprocable plunger 23 of the press (Fig. I) is caused powerfully to descend into the extrusion cylinder, whereby the metal of the billets is forced through the extruding dies 22, forming an elon- 40 gate article E. The cross section of vthe extruded article conforms to the bore (the throat and bearing) of the particular die employed in the press. In this case the billets for introduction to the press orpresses 2 are cast and prepared for ex- 45 trusion in the upper stage A. As disclosed in our co-pending application Serial No. 81,428,.

"Then, by means of the usual pouring pots or (Cl. 207--1l siphons (not shown), the billet molds 3.

The molds are preheated to such degree, or heat is applied at such intensity to molds during, or immediately after, casting,.that the cooling of G the ycast -metal is arrested at approximately 956 F., that is, at theproper temperature for extruding This critical temperature may, of course, ber varied for aluminum alloys of dierent compositions. By such utilization of heat- El@ heat applied to the molds-thc rate of cooling of the billets is retarded and graduated.

The billets are held at extruding temperature in the heated molds, until, so far as possible, homogeneity of structure and uniformity of temil@ perature are established throughout the bodies of the billets. Upon removal from the molds, the billets are introduced immediately to the extru`= sion cylinders 20 of the presses 2, and in known manner are extruded into the desired elongate gc shapes E. A small ladle of molten aluminum is poured into each extrusion cylinder before a new billet is inserted, whereby the leading end of such newy billet is fused and welded to the stub remaining in the cylinder from the billet last p5 extruded. Thus, the extrudlng operation is in effect continuous, that'is, an extruded article of desired continuity may be produced. In some cases a heating furnace 'i is installed between the billet molds and the presses, whereby, if there be a break-down oi one press, or ii for some other reason the supply of billets at extruding temperature` exceeds the capacity oi the presses, the surplus billets may be introduced to the furnace 'land held substantially at the temperature at which they leave the molds.

In accordance with the present invention, the lower .working stage B includes a Vertical workreceiving chamber 32. The. vertically extruded article E is fed in vertical', rectilinear course -irom the upper working stage to' the lower, through a passage 30 in the floor C. Means are provided in such lower stage for receiving the work, and, in this case, we provide on the floor of the lower stage and beneath each press a roller 5 table 8. The work-receiving face of each table 8 includes a curved reach 8a that extends upward from and beyond the end of the table, and the outer orupper end of such reach is secured to a frame 8b, as indicated diagrammatically -in Fig. I; The extruded material E, fed downward through the platen 4l, passage 30, and vertical work-receiving chamber 32, moves-in continuous length Vfirst over the curved extension 8a and then upon the table 8. As shown in the w metal is seemed into drawings. the' vertical pass from the extruding die to the conveyor table is of relatively great ex,-

tent, and in it the work moves freely in rectilinearI course, there being neither guiding blocks nor work-enclosing walls against which the surface o1' the lextruded article may slide and becomemarred. 'I'he several tables 8 arranged beneath the extrusion presses may each be of such longitudinal dimension as to receive and support a continuously extruded article of desired length. Adjacent each work-receiving table 8, or between the two work-receiving tables of the two extrusionpresses 2 shown in Fig. II, we organize a. horizontal stretching `table I3, a known piece of apparatus, employed in aluminum mills for stretching the extruded work lengthwise, to remove twists and other irregularities. If specications require it, the material is next cut into lengths on a shearing ta-ble I0 (Fig. II), aligned with the stretching table, and then the sheared pieces are put through one or more draw-benches II and annealing-furnaces I2. The shearing table, draw-benches, and annealing furnaces are known apparatuses commonly employed in the treatment of extruded metal, and detailed consideration of them is unnecessary to an understanding of our invention; suffice it to say that such apparatuses are, conveniently, arranged with the work-receiving tables 8 in the lower workingstage B.

In the manufacture fof certain shapes, itis desirable that the extrudedl article leaving the chamber 32, it being noted that the roller extension 8a is detached from frame 8b and swung aside. Indeed, the table 8 itself is mounted on wheels 8c, so that it may be laterally shifted from aligned position beneath the portion of railv 9 shown in Fig. III.

Trolley-members 3l are mounted for travel on the rail conveyor system (9), and each trolleymember carries a clamp 35. Between the upper and lower working stages A and B, a workmans platform D is provided. In service, the operation of the extrusion press is momentarily `arrested when the lower end of the vertically extruded article E' approaches .the bottomv of the extrusion chamber 32, and the workman on platform D secures the clamp 35 of a trolley-member to the arrested article, as shown in Fig. III. Then, he .shifts the power saw 33 from right to left upon its supporting base 36 and into the position shown in Fig. III, whereby the article E' is severed on a plane lying immediately below the passage 30. The detached length of the article hangs vertically from the trolley-member 34, and in such position it is htransportedto the horizontal stretching apparatus I3. Immediately upon removal of the sheared article from vertical extrusion chamber 32, the saw is shifted from position beneath the work, and the extruding operation started again.

In the usual practice of' extruding aluminum in horizontal direction the work passes to a work-receiving table immediately upon passing from the extrusion die. There is a marked tendency in such case for the hotextruded metal to become distorted and marred. These objections are eliminated (or minimized) in our practice, it being noted that during the extrusion in vertical direction nothing touches the work from the time it leaves the die and until the extruding operation is arrested for the shearing and clamping steps alludedl to. The extruded metal `is subjected to tension produced by its own alloying metals in the aluminum tend to precipitate at the surface of the extruded article and lto oxidize more rapidly than the aluminum itself.

The use of a water-spray upon the extruded work is known to be benecial; it chills the metal in such manner as to prevent the precipitation of the included alloys, and to inhibit surface oxidation. It will be understood that the extruding dies must not be unduly chilled, for the aluminum will freeze in such manner as to rupture the dies and make extrusion impossible. Thus, inl a horizontal press a water-spray cannot be organized in such close proximity to the die as to achieve the most beneiicial results.

In accordance with our invention, we arrange a water-spraying device 31 (Fig. III) immediately below the extrusion die 22; the Waterspraying device is arranged above the saw 33 (or other shearing means employed) and above the work-receiving or conveying means 8 and 9. No sooner does the extruded aluminum leave the extrusion die and pass into the open air beneath than it is subjected tothe chilling and heattreating effect of the spray. The water (or other liquid) applied `to the vertically extending extruded article runs downward, forming a protecting lm on the surface of the work, and inhibiting precipitation of the alloys'in the metal. Upon owing to the lower end of the work, the liquid enters a reservoir 38 provided at the base of the extrusion chamber 32. In keeping with economy, the liquid lmay be recirculated from the reservoir 38 to the spraying device 31.

By virtue of such apparatus we gain the desired ends,.and insure that no water shall reach the extrusion dies, as it frequently does in horlzontal presses. Danger of die breakage is minimized.

In.still iurther refinement of present practice, we advantageously stretch the extruded articles (E') in vertical'rather than in horizontal position. And to this end we secure upon the oor of the working stage B a power cylinder 39, whose vertically reciprocable plunger carries a pair of clamping jaws 40. Subject to the control of suitable valves (not shown), compressed air (or water under pressure) is adapted to eifect' the vertical-reciprocation of the plunger. In practice, each extruded piece E' is by a trolley-member 34 carried to a position above the opened, and the piece is transported on the rail conveyor 9 to the shearing table III or other apparatus for treating the product.

It will be understood that within the terms and intent of the appended claims various modifications and elaborations will be evident to the engineer. And we may remark that in our copending application .Serial No. 130,568, filed March 12, 1937, lparticular refinements in extrusion press structure per se are disclosed.

We claim as our invention:

1. An extrusion mill including an upper working stage and a lower, said upper stage including means for extruding an elongate article and feeding the extruded article to said lower stage, a conveyor including means for engaging the upper end of an extruded article, and transporting such article depending therefrom in vertical direction, and means for securing the lower end of said vertically extending article and cooperating with said conveyor in stretching the article.

2. An extrusion mill including a vertical press for extruding an elongate article in vertical di` rection, aconveyor vadapted to `receive the extruded article, said conveyor including means for engaging the upper end of said article, whereby to support the article vertically depending therefrom, and means for securing the lower end' of the supported article and cooperating with said I mst-mentioned means in stretching the article.

engaging means in vertical direction, to stretchand true the bodies of said articles.

4. In the vertical extrusion vof metal into the form of an elongate article, the herein described method which comprises delivering the gradually extruded metal, hanging freely from the extruding die, through an elongate vertical pass,

'- truding die, through an elongate vertical pass,

and, by subjecting the gradually extruded metal l leaving the mouth oi the die to tension produced by the weight of the metal hanging freely below, inhibiting distortion in the extruded article, and, when the extruded article reaches desired length and while it is suspended in vertical position, transversely severing the extruded metal below the mouth of the extruding die.

6. An extrusion mill including an upper working room having a press with a die arranged to extrude an article in vertical direction to a lower working room, and powerfully operated shearing means mounted adjacent to the topv of said lower room and at an interval beneath the die of the press in said upper room and movable transversely of the line of extrusion for severing the extruded article.

7. An extrusion mill including a press with a die arranged to extrude an article in vertical direction, a Work-supporting clamp arranged adjacent to the top of said lower room but at an interval below said die, and powerfully operated shearing means mounted in the vertical interval between said die and said clamp and movable transversely of the line of extrusion for severing the extruded' article.

8. An extrusion mill including a press with a die arranged to extrude an article in vertical direction, a conveyor arranged beneath said die to travel in direction transverse to the vertically extruded article, said conveyor including a device for securing the article, and means operable in the vertical interval between said device and said die for severing the extruded article when engaged by said device.

CHAME D. SKINNER.. LEO C. BRADLEY.

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