US2865502A - Apparatus for guiding extrusions - Google Patents

Description

Dec. 23, 1958 ANSCHER APPARATUS FOR GUIDING EXTRUSIONS Filed July 10, 1952 m w m m Bernard Anscher 2 05%? QJBW APPARATUS FOR GUIDING EXTRUSIONS Bernard Anscher, New York, N. Y., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Army Application July 10, 1952, Serial No. 298,072

1 Claim. (Cl. 207-16) Extruded parts which issue from the extrusion press are subject to forces which tend to cause bending or distortion. This is due to the fact that the extruded parts as they emerge from the press are still hot, the temperature in some cases being even higher than the temperature of the billet due to very high extrusion speed. The parts are therefore in a soft condition where the slightest force due to unsymmetrical flow of the metal through the die orifice or even the weight of the part will cause bending or distortion. In normal extrusion practice there always exists certain irregularities in flow condition, temperature and friction during the extrusion. In order to produce fairly straight extrusions it is common practice to use pulling devices which keep the outflowing extrusion under slight tension. This is accomplished by clamping the leading end of the extrusion withtongs which are then pulled along the run-out table either by an operator or by mechanical means. It will readily be understood that the front end of the extrusion cannot be grasped by tongs until it has emerged from the front platen. By this time, however, a considerable length of extrusion, on the order of several feet, has left the die without being guided in a straight axial position.

The practice described above has therefore been found unsuited to the extrusion of relatively short parts which, however, as in the case of gun barrels, must be free from distortion and warpage of any kind. Existing guiding and pulling devices are obviously unsuited for this type of extrusion since they can be applied only after a considerable portion has been extruded without any precautions having been taken to prevent distortion.

It is therefore the principal object of this invention provide an apparatus for preventing distortion of an extruded part from the time it leaves the die assembly, thus preventing undesirable deflection or distortion of the extrusion at its most susceptible position, i. e. where it is at highest temperature and softest condition.

Further objects and advantages of this invention will become apparent in the following detailed description thereof.

In the accompanying drawing,

Fig. 1 is a vertical section through a portion of an extrusion press showing one form of my invention applied thereto.

Fig. 2 is a section taken on the line 2-2 of Fig. 1.

Fig. 3 is a section taken on the line 3-3 of Fig. 1.

Fig. 4 is a section taken on the line 4-4 of Fig. 1.

I have disclosed the invention as applied to the extrusion of tubes, but it will be understod from the following description that the principles of this invention are applicable to the extrusion of various other crosssectional shapes.

As disclosed in Fig. 1, standard parts of an extrusion press are shown as comprising a container 10 having a cavity in which is placed the billet 11 from which the extrusion is to be made. The hot billet 11 lies within a cylindrical chamber 12 in which operates a ram 15 having a pressing disk 16 which fits the walls of cylinder 12 closenited States Patent lice 1y. Since the product to be extruded in the case here described is a tube, the ram is provided with a centrally disposed mandrel 17. As the combined ram and mandrel moves forward (toward the right in Fig. 1) against the billet, the forward end of the billet is forced through the annular clearance space between the mandrel 17 and a die 20 to form the round tube T. As the tube emerges from the die, it enters the bushing 21 within a die bolster 22. The die assembly comprising the die 20, bolster 22 and its bushing 21 is supported in position by a die carrier 23 held upon the front platen 27. The bushing 21 may be fixed to the bolster 22 by means of bolts 24 extending through a flange 25 on the bushing in engagement with the outer surface of the bolster. The die carrier 23 may he slid into the opening 26 in the front platen 27 and held in position by a horseshoe locking frame 30 which is vertically slideable in a recess 31 in the platen by means of a tie rod 32. In this manner the ram and die assembly may be coaxially aligned and held in fixed relation.

Heretofore, as the extruded part emerged from the die assembly, it was supported upon a run-out table 35 which was supported on a tubular frame 36 by means of a support-and stifiener 37 and flanges 38 engaging cooperating flanges 38' on the tubular frame (see Fig. 2). The tubular frame 36 is itself fixedly mounted in central opening 39 within die carrier 23 with theaxis of the frame 36coinciding with the axis A-A of the extrusion as sembly. The frame 36 may be fixed to the carrier by means of bolts 41 and flanges 42.

As described above, the extrusion press is of a standard design, from which it will be seen that the extruded product T eventually rests upon the run-out table 35, and after several feet of material has been extruded, the leading end of product T will be accessible from the front platen opening 26 so that it may be gripped by tongs which are then either manually or mechanically operated to place tension on the extrusion for the purpose of preventing distortion. However, as set forth in the introduction hereto, this is not possible in the case of relatively short extrusions, such as gun barrels. It is therefore desirable to provide means which will prevent the initiation of distortion in the extrusion even in the case of sho-rt extrusions. For this purpose, I have found that the prevention of distortion in the extruded material in the interval beginning almost immediately after the extrusion leaves the die assembly is the key to preventing later distortion; and that if such distortion can be prevented in the portion of the extrusion immediately leaving the die assembly, and for a predetermined interval of time thereafter, it will overcome the tendency of the extruded material to warp when it reaches the runout table.

To carry out the above principle, I have provided means for preventing lateral distortion of the extruded material for a predetermined time interval after it leaves the die assembly. That is to say, I provide means for preventing movement of the extruded material along either of two axes at right angles to each other and transverse to the extrusion axis A-A. In Fig. 1, movement of the extrusion along either of two axes at right angles to each other and transverse to axis A-A is prevented by means of a circumferential guide bushing 50 having an internal bearing surface 51 whose cross-sectional opening closely fits the shape of the finished extruded body. For the length that the extrusion T passes through the central bearing surface 51 of guide bushing 50, no lateral movement of the extrusion along either of the two axes at right angles to each other is possible. The guide bushing 50 is supported within frame 36 by means of spokes 55 and close to the exit of the bushing 21 in bolster 22 of the die assembly. Therefore almost as soon as the tortion can set'in', itis passed through the closely fitting guide bushing 50. The bushing is made of predetermined length such that by the, time the extruded material haspassedth'rough'the bushing, the'tendency. of the extrusion to warp and distort laterallyhas been overcome, so that a'straigh't'axis extrusionwi'll reach the'run-out table and be" supportedfihereon. Since the extreme heat ofith'e extrusion wouldtend to distortand' wear the inner surface'SI. of" the guideb'ushingjfll su'ch' surface can be kept atrelatively 'low temperature by, supplyinga cooling fiuidlfiom a source 56 controlled by valvei57 through pipe'58leading toan internal annular chamber,59 within. theguide bushing150f The flui'diim'ay discharge through a pipe 60.

Havingdescribedimy invention; what I claim and, de-

sire: to secure"byiLetters'Patentis:

An extrusion press including aco'ntainer having acylindlical chamber" for'receiyin'gjmaterial. to' be, extruded therein, a ram, aipressing disqat the forward'end' of 'said ram slidably fitting'saidchamb'cr and a mandrel integral with and extendingforwardly'in axialrelation from said disc in' said'chamb'er; adie assembly-located at one end of said chamber comprising a dierhavinga circular opening in coaxial alignment with said'cylindrical chamber through which said materialis forced by said ram, a platen havingja" cylindrical opening disposed forwardly, of "said container,, said opening in saidplaten'ibeing'of'substantially greater diameter than said chamberin said'container and in'coaxial.alignment therewith; adie carrier'having a cylindrical bore. in" coaxial alignment withsaid. chamber slidably fitting andjnormally disposed in the rearward portionof said cylindrical opening in said platen, a substantially horseshoe shapediframe'vertically slidablein said platen adapted tolock said'die carrier'in its rearward po- 4 sition, a bolster carried internally by said die carrier having a" cylindrical" bore" in coaxial alignment with said chamber, a tubular bushing secured to said bolster in said cylindrical bore, mean for supporting substantially the entire length of an extruded portion of said material comprising a tubular frame mounted in said cylindrical opening in said die carrier; a;r,un-out table having a concave semicylindrical supporting surface aligned, with said opening'in said die supported by said tubular frame, and means for preventing the warpingand distortion 'oftsaid extruded material comprising a' guide" member spaced from the aforesaidstubular' bushing-and'supportcd bysaid tubular frame, said, guide member defining anouter wall, an inner wall concentric with said outer wall, said inner wall flaring rearwardly and outwardly; along a portion of its rearward length and forming a bearing surface along its frontal portion closely fitting the shape of said extruded material, said inner and said outer walls formingan annular cha'mben closed atits' ends thereof and having an inlet pipe'and an outlet'pipe connected thereto for supplyinga coolant to said annular chamber and discharging it-therefr'om;

References 'Cited" in the file of thisg atent'

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