US2500890A

US2500890A - Metal working method and mechanism

Info

Publication number: US2500890A
Application number: US618541A
Authority: US
Inventors: Paul D Wurzburger
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-09-25
Filing date: 1945-09-25
Publication date: 1950-03-14
Anticipated expiration: 1967-03-14

Description

P. D. WURZBURGER METAL WORKING METHOD AND MECHANISM March 14, 1950 3 Sheets-Sheet 1 Filed Sept. 25, 1945 INVENTOR. PAUL 0; h/uezawzazz BY Arne/w: Ys

March 14 1950 p, WURZBURGER 2,500,890

METAL WORKING METHOD AND MECHANISM Filed Sept. 25, 1945 3 Sheets-Sheet 2 INVENTOR. 0 Paul. 0. hlunzaueesz Emi 152;

47-7-02 NE s March 1950 P. D. WURZBURGER 2,500,890

METAL wonxmc METHOD AND MECHANISM Filed Sept. 25. 1945 3 Sheets-Sheet 3 I INVENTOR. AUL 0. W02 Z BURGER.

Arr-0R NE Ys Patented Mar. 14, 1950 METAL WORKING METHOD AND MECHANISM Paul D. Wurz'burger, Cleveland Heights, Ohio Application September 25, 1945, Serial No. 618,541

19 Claims.

This invention relates to fittings and metal working and more particularly to wrought fittings such as Ts, crosses or other forms having more-than two angularly disposed legs and to methods and mechanisms for making such fittings.

In the art of making wrought fittings various methods have been employed to make fittings in the T or cross or other multi-leg forms. It has been common practice in the making of wrought Ts to start with a tubular blank in straight form and extrude the leg of the T transversely from the head portion thereof by means of internally disposed plastics, fiuids, balls or other instrumentalities. In the practice of my invention I provide, for example, that Ts, be made from an elbowed form of blank rather than a straight form extruding a leg or branch in longi tudinal alignment with one of the legs or branches of the angled work piece.

It is one of the general objects of my invention to provide a method for making Ts or other multi-legged forms of fittings from an elbow blank wherein one of the branches of the head of the T rather than the shank thereof is extruded. Another object of my invention is to form wrought Ts or other multi-legged forms of fittings in a manner whereby the wall thickness of the product may be maintained substantially uniform and with materially greater uniformity than has been obtained in prior practices.

A further object of my invention is to provide a method for making Ts, crosses and the like by the rectilinear movement of rams and mandrels whereby to avoid curvilinear or compound motions or flows of balls, plastic filler and the like and avoid the cost and trouble of insertion and removal or disposal of the latter from the product. A further object is to provide a method and mechanism for making Ts, crosses and the like with simply constructed rams and mandrels by the relative movements of which the wall thickness, grain structure and character of the finished product may be controlled and improved. Another object of my invention is to provide a method and mechanism for making Ts, crosses and the like which will be more economical and practicable than prior known methods and which will make possible the more economical manufacture of fitting having improved physical and structural characteristics as compared with prior practices and products. Another object is to make Ts, crosses and the like the radius of curvature of the corners of which are small with a wide range of materials such as copper,

brass, aluminum alloys, steel, stainless steel and the like.

Other objects and advantages will appear from the following description of a preferred and certain modified form of my invention reference being had to the accompanying drawings in which Figure 1 is a side elevation of a blank straight cylindrical work piece; Figure 2 shows the work piece in elbowed form preliminary to,

making the T according to tion; Figure 3 shows the T its essential form and characteristics; Figure 4 shows the T of Figure 3 after having the ends of its legs sized or provided with connecting sockets; Figure 5 shows the elbowed piece of Figure 2 disposed in one of a pair of forming dies with rams and mandrels in position preliminary to working the stock; Figure 6 is a view similar to Figure 5 showing the parts in median position during the working operation; Figure 7 is a view similar to Figures 5 and 6 showing the parts in a completed position at the end of the work strokes; Figure 8 is a section through the work piece taken along the line 8-8 of Figure 6; and Figure 9 is a view of a stage in the operation similar to that shown in Figure 6 with a cross form of die and a modified arrangement of rams and mandrels adapted to making crosses from a T shaped work piece.

Since my method as applied to make right angled T fittings is advantageous and is illustrative of the application thereof to other forms, reference to such Ts and the making thereof should be taken herein by way of example rather than limitation. In its general aspects my method in its preferred form contemplates working straight lengths of tubular stock, Figure 1, into a short radius elbow form, Figure 2, preferably in the manner described in my copending application Serial No. 611,600, filed August 20, 1945, then working the elbow into the T form, Figure 3, by flowing or extruding metal from one or both legs of the elbow in the direction of the axis Of one leg and transverse the axis of the the instant invenproduct finished in cylindrical work piece i, Figure 1, such as a cut length ,of half-hard wrought ti" 0. D. copper tubing of wall thickness of about .035", or of other desired size, material and proportions as mentioned in my said copendling application and hereinafter more fully discussed, I prefer to first work the piece into the short radius elbow form 2, Figure 2 as described in said application. Briefly that working comprises advancing the piece longitudinally into and through the short radius bend of an angled cylindrical channel of split forming dies while permitting the leading end of the piece to be wrinkled and deformed under the influences of the forces and reactions that turn the leading leg of the elbow at right angles (or other particularly desired angle) to the trailing leg. That working also includes smoothing or ironing out the wrinkles and deformations in the leading leg of the elbow and producing the short radius elbowed product 2 characterized by walls of substantially uniform thickness, except preferably at the inner corner of the bend the hollow ram is with its interiorly associated mandrel i8 is advanced into the section iii of the channel C with the end of the ram bearing on the end of the leg 3 of the elbow and the mandrel ll entering the leg I to an initial position substantially as shown in Figure 5. Preferably the hollow ram i i has a wall thickness substantially corresponding to the wall thickness of the work piece and has a close sliding fit with the interior of the section III of the channel C. The mandrel i8 preferably has a close sliding fit with the interior of the hollow ram it and by the same token has a close sliding entering engagement into the leg 3 of the elbow 2. The ram i6 is preferably cylindrical throughout that portion of its length which enters the work piece and has its leadin end i I rounded oi! but a little to facilitate its entry into the piece and the working thereof as will more fully appear.

A second hollow ram 20 with an internally disposed mandrel 2| enters the section II of the channel C; the ram 20 engaging the end of the leg 4 and substantially corresponding in wall thickness to the wall thickness of the work piece. The mandrel 2| has a close sliding fit within the ram 20 and hence a close sliding initial fit within therein. Preferably the ratio of the radius of curvature r of the outer surface of the inner bend of the elbow 2 to the outside diameter d of the piece is of the order of V4 or less.

Whether or not the elbow 2 be formed in accordance with the precepts of my copending application, the elbowed piece 2 having the characteristlcs above mentioned and preferably with the legs of unequal length is worked in-the novel way worked or extruded leg of the elbow 2. My pref-' mandrel it as shown in Figure 5 is bifurcated erence for likenesses and differences between the lengths of the legs of the piece 2 will more fully 7 appear below.

To produce the T 30 from the elbow 2 the elbow is placed in the T shaped channel C of one of a pair of forming dies D, which when juxtaposed according to common practice complete the cylindrical T shaped form of the whole of the channel C giving it the contour of the exterior surface of the T desired to be formed therein. As shown in Figure 5 the piece 2 has its longer leg 3 lying in the entering head section 10 of the channel C and with its shorter leg I lying in'the middle angled or leg part II of the channel C. The

channel C also comprises a forming head section the leg I of the work piece 'and is externally cylindrical at least throughout the portions that enter the leg I of the piece except that its leading end 22 is relieved subsantially as shown in Figures 5 to 8. As shown in Figure 5 the end 22 is cut away transversely of the plane of the channel C along curving lines that substantially equal the lines of intersection of the cylindrical exterior surfaces of the mandrels 2| and it, see also Figures 6, i and 8, and when themandrel 2| is advanced to its initial position shown in Figure 5, it may just about contact the outer bend of the elbow as at 23 without deleteriously or substantially bearing thereupon. The end 22 of the as viewed in Figure 8, having an internal semicylindrical surface 24 which closely receives the external surface of the mandrel l6 when the same is advanced transversely thereof as shown in Figures 6 and 7. In relieving the end of the mandrel 2| the purpose is to have a close sliding with the side of the mandrel i6 and also to fill up 'a maximum of space interiorly of the elbow and of the T to be formed at the intersection of the legs thereof.

When the mandrel it enters the surface 24, the inside corner of the elbow is filled substantially as full as the intersecting cylinders of the exterior surfaces of the mandrels I6 and 2| can flll it. It will be noted in Figure 5 that the inside of the inner corner of the elbow 2 is advantageously thickened as shown before any of the instant working is begun so that this part of the elbow is resistant to collapsing upon the intersecting mandrels and is so proximate to contact therewith that the little extra thickening required to bring about substantially full contact will take place before any substantial folding or wrinkling of the inner corner of the elbow occurs as the rams move in converging directions toward this corner of the work while the mandrels assume their intersecting'and supporting positions.

After the parts are positioned as shown in Figure 5 the rams l5 and 20 are forcibly urged inwardly of the channels it and II, whilst the mandrel 2| is heldstatlonary in the position of Figures 5 to 8, and the mandrel I6 is advanced or permitted to advance in the direction of inward movement of the ram I! but at somewhat diiferent times and difl'erent rates of speed. Where as herein illustrated the leg 3 of the elbow 2 is longer than the leg 4, and I desire that the T 30 be produced with legs of equal length, the ram will have a greater travel than the ram 20, and since I prefer that the rams l5 and 20 act simultaneously and with continuous movement, the ram IE will move at a greater speed than the ram 20. My observations lead me to believe that the first movements of the rams l5 and 20 tend to thicken the walls of the legs 3 and 4 of the elbow whereby to substantially eliminate the clearance between the inner surfaces of the elbow and the adjacent surfaces of the mandrels. Continued forcible inward movement of the rams l5 and 20 appears to have somewhat difierent respective eifects as will presently appear. As the ram l5 continues to advance, as from the position of Figure 5 toward and to the position of Figure 6, the material of the wall of the leg 3 tends to grip the mandrel i6 and move it along with the ram. At least at or prior to the beginning of the stroke of the ram i 5 it is practicable that the mandrel II be first advanced to intersection contact with the surface 24 of the mandrel 2i and then not forcibly advanced but rather permitted to move or fiow with the movement of the stock of the leg 3. As shown in Figures 5 and 6 a short movement of the mandrel it will bring that part of its cylindrical side wall adjacent its end I! into sliding contact with the surface of the mandrel 2i, Figure 8, whereby to prevent the flow of metal from the inner corner of the elbow toward the center of the bend. Similarly the initial freedom of movement of the mandrel It tends to avoid forcible drawing or stretching action by the end I! of the mandrel against the outer wall 23 of the bend of the elbow. As the ram l5 and mandrel it continue their movement toward and through the position shown in Figure 6 all of the stock of the wall of the leg 3 is being advanced within and along the section In of the channel C but it may have substantially no direct longitudinal movement at the innermost corner of the elbow after the stock has filled the space between the intersecting and contacting 1 mandrels l6 and 2! or after the wall at the innet comer adjacent the radius r of the piece has thickened to substantially fill the space adjacent the intersection mandrels. Therefore the flow of metal tends to take curvilinear paths from the inner side 5 of the leg 3 adjacent the inner bend of the elbow up and over the intersecting mandrels. At the same time the metal in the outer side 6 of the leg 3 adjacent the outer bend 23 of the elbow tends to flow directly into the section l2 of the channel C and tends to be hastened in its movement by the convergence of the flow from the opposite and inner side of the leg In over and around the intersection of the mandrels through the center or intersection of the T. Meanwhile the mandrel l8 being at least free to flow with the stock tends at least in these initial stages of movement of the stock to act as a floating filler resisting inward radial movement of the stock, i. e., resisting increasing the thickening of the walls, while going along with and not interfering with the longitudinal and curvilinear-longitudinal movement of the stock in the general direction of movement of the ram l5. While I speak of the preferred free movement of the mandrel it as 8 if it were literally permitted. to flow with the movement of the stock, I find it also practicable to induce or control movement of the mandrel I 6 whereby to cause it to move in much the same way that it tends to move under the forces and influences above discussed.

The foregoing has assumed that metal has not been permitted to fiow out in the direction of the leg 4, and since the ram 20 acting on the leg 4 of the elbow is moved, simultaneously with the ram l5, inwardly of the section II of the channel C it tends to feed the stock of the leg 4 into the bend of the elbow, i. e., into that portion of the work which progressively becomes the center or central intersection of the T that is being formed. The tendency of the stock to flow from the leg 4 of the elbow into the section I 2 of the channel C and into the extruded leg 3| of the T is, according to my best observation, influenced both by the direct effect of the ram 20 and also by the flow of-the metal as induced by the ram I5.

When the parts in the course of their move ments have assumed about the position shown in Figure 6 the flow of metal as induced by the ram l5 tends to draw metal outwardly, i. e. rightwardly as viewed in'Figures 5, 6 and 7, from the outer wall 8 of the leg 4 into the bulge 9 of the wall 23 which in the position of Figure 6 begins to take the form of the extruded leg of the T. If the ram 20 were not advanced at all, my observation has been that the outer wall 8 of the leg 4 would tend to be thinned by the outflow of the metal therefrom whilst the inner wall I would tend to be thickened adjacent the bend under the influence of movement of the ram 15. This tendency of the metal to flow as above mentioned would tend to bend the end of the mandrel 2| downwardly as viewed in Figures 5 to 7, not only to the possible injury of the mandrel but also with the eflect of modifying the thickness of the walls of the leg 4. Therefore I prefer that the ram 20 be advanced inwardly of the section II of the channel 0 at a rate which will at least maintain the thickness of the outer wall 8 of the leg 4 and will induce a flow of metal from the stock of the leg 5 sufiicient to maintain a desirable wall thickness throughout and at the inner bend 32 where the extruded leg 3! joins the worked shank or leg Li of the T 30, see Fig. 7. In practice I have found it practicable to cause the ram 20 to have its stroke about half the stroke of the ram i5 and to provide the elbows 2 with their legs :5 and 3 respectively proportionate so that such movements of the rams I5 and 20 will leave the corresponding'worked head and shank parts 31' and 4' of the T 30 of equal or other desirable relative lengths. Thus as the working continues through the phases shown in Figures 6 and 7 about the stock of the extruded leg 3| may be deemed to have emanated from the original leg 4 of the elbow 2 and about of the stock will have emanated from the original leg 3 of the elbow 2.

The stock of the inner wall I of the leg 6 will flow under the influence of the ram 20 in a curvilinear path toward and around the intersection of the mandrels i6 and 2t and through the central intersection portion of the T that is being formed. As the rams I 5 and 2t progress in their movements above described,

and flowing along with the moving mandrel it. I prefer to induce movement of the mandrel it by the application of appropriate force whereby the metal flowing in part past the stationary mandrel 2i to keep the end l'l thereof proximate to the growing bulge 9 as it enters and fills the section is of the channel C. While I do not prefer to exert a drawing force upon the extruded stock of the bulge 9 of the work piece by the end H of the mandrel it I do prefer to forcibly advance the mandrel It to substantially fill the bulge whereby to control the wall thickness of the extruded leg 3| of the T as the same tends to fill the section I! of the channel externally of the cylindrical surface of the mandrel ii. At all times the mandrel 2| is held stationary in the position shown in Figs. to 8.

In Figure '7 the working and extrusion will have first proceeded to the condition shown in part in dotted lines as at Q where the end of the extruded leg 3| covers the shearing orifice ll of the shearing die 42. Thence further forcible movement of the end ll of the mandrel 36 will shear out the disc-like end 9" of the extruded leg 3| leaving a square right cylindrical open end for the extruded portion 3| of the head of the T 30. I prefer that the rams l5 and 20 will have or will continue to exert substantial pressure upon the piece whereby to fill out the stock into the section I2 of the channel C adjacent the upper wall of the shearing die I whilst or after the end 9" of the extruded leg If is sheared through the orifice ll. It will be noted that at this stage of the work that the reduced legs 3' and 4' are substantially equal in length to the extruded and finished leg 3|; that each leg of the T is square ended and right cylindrical throughout its length to its merger with the central intersection of the T, and that the product is of substantially uniform wall thickness throughout excepting only as the wall adjacent the inner radius 1' may be thickened under the influence of the converging flows and forces above described. 1

Working the softer metals such as soft copper the thickness adjacent the radius 1' may progress to the degree where the 1'- has a substantially sharp inside corner at this point, a thing which I find to be without detriment and perhaps with advantage as to the fluid flow characteristics within the product and with advantage in respect to the strength thereof. While I find it practicable to merely maintain a uniform wall thickness at the complementary inside corner 32, it is also practicable by the exertion of further pressure and movement on the piece through the rams l5 and 2|! while extrusion of the leg 3| is prohibited by the mandrel Ii filling the shearing orifice 4| of the shearing die 42, to thicken up the corner 32 to be substantially symmetrical with the complementary corner adjacent the radius 1'.

After the T 30 has been formed as shown in Figure 7, the rams and mandrels may be withdrawn until they are entirely removed from the interior of the worked piece. This rearward movement of the mandrels through the head of the T and the leg 4 thereof tends to burnish and center the inner surfaces of the product. Thereafter the finished T 30 may be removed from or ejected from the dies D when the same have been opened in the known way.

While I have not shown any specific means or mechanisms for moving the rams I5 and 20 or moving or holding the mandrels I6 and 2|, I contemplate that their movement may be satisfactorily effected by known mechanisms such as mechanically actuated cams, levers, toggles or fluid motors suitably correlated for the desired movements, sequences and successions of movement or holdings thereof hereinabove described.

In the practice of my invention 1 have found it expedient to lubricate the mandrels |i and 2| as well as the work piece 2 whereby to facilitate the movements of the parts hereinabove described. Those skilled in the art will recognize various fluids or mixtures of fluids ranging from light lubricating oil to soapy solutions, for cold working,.as appropriate. I have observed that occasionally bubbles of air or lubricant may tend to overflll the work piece tending to stretch the bulge 9 unduly, a thing which I have sought to avoid by the restrained movement of the mandrel II in respect thereto. As against any deleterious effects from this action I have found it practicable to pierce the outer corner of the elbow 2 as at about the point 33. see Figure 2, with a small hole to permit the free egress therefrom of such excesses of content as might otherwise tend to draw rather than extrude the formed leg of the T or the bulge S of the work piece during the: formation thereof. Alternatively a small longitudinal bleed hole may be provided interiorly of the mandrel is through which excess air or lubricant may escape.

While I have referred to the T 30 as shown in Figures 3 and '1, as a finished product of my invention I contemplate that the piece 30 may be further worked as by sizing the ends to make sockets S whether of the same or different size or otherwise treating the ends of the piece for other purposes according to known and common practices. Since the T 30 as produced according to my invention has the desirable characteristics of uniform wall thickness, right cylindrical square ends and the like and with short radius and strong inner corners, it is advantageously adaptable to further finishing and sizing as exemplified in Figure 4 without liability to failure under the influences of such working.

Moreover the "flnished T as of Figure 3 may be used as the work piece for the making of a cross, see Figure 9. Here the die half D contains a cross-shaped channel C which comprises the four legs 5|), 5|, 52 and 53 intersecting to form the cross-shaped passage C. The shearing die 42 disposed at the lower (as viewed) end of the leg 52 is positioned to perform the same work in the same way as described in connection with the die D as shown in Figure 7. In making a cross the work piece takes the form of the T in the first instance with the head lying in the sections II and 53 of thechannel and with the shank lying in the section 50. In Figure 9 the parts are shown in a median position of working corresponding roughly to the position of the parts as shown in Figure 6 in respect to the making of the T from the elbowed form.

The T shaped work piece initially has its shank SI of somewhat longer length than shown in Figure 9 and its head branches Ill and 63 also a little longer than shown in Figure 9, it being assumedthat the respective rams I5, 20' and 20" have advanced a little from an initial position, not shown, to the median position shown in Figure 9 thereby shortening the three legs of the work piece from their initial lengths. As mentioned above I prefer that the leg which lies in the direction diametrically opposite and in the direction of extrusion be longer than the legs which lie transversely thereof so that the greater part of the flow of the metal is diametrically across the intersection as is the preferred form of making the T above described. Therefore I prefer that the work piece in the form of a l' i when it is first placed in the dies D, have its shank 60 somewhat longer than either of its head branches 6| or 63.

After the work piece in the T form is placed in the channel C of the dies D' the ram I and mandrel l6 entering the section 50 of the channel C engage the end and extend interiorly of the shank 60 of the T blank in a relation corresponding to the relation of the mandrel I6 and the ram l5 of the leg 3 of the elbow 2, see Figure 5. Rams 20' and 20" enter respectively the

sections

50 and 53 of the channels C to engage the ends of the head of the T. These rams may substantially correspond to the ram 20, see Figures 5 through 7, and do substantially the same work in the same way. Mandrels 2| and 24" coacting with the rams 20' and 20" enter the head branches of the T blank and substantially contact in the mid-section of the channel C preliminary to the working of the piece. Each of the mandrels 2i and 21" substantially corresponds to or may be identical with the mandrel 2| having the end configuration thereof as shown in Figures 6 to 8 inclusive; the interior bifurcated end surfaces of the mandrels 2| and 22' substantially coinciding with the projection of the cylindrical surface of the mandrel it when the mandrels 2i and 22' are in working position. After the blank of the T shaped form is positioned in the channel C the mandrels l6, 2! and 22' are advanced interiorly of the respective parts of the work piece, the mandrels 2i and 22 substantially contacting as shown in Figure 9, and the mandrel IS in the first instance preferably reaching into the cylindrical bifurcated end surfaces of the ends of the mandrels 2| and 22' preferably a little further than is practicable in the initial step in forming the T as shown in Figure 5. Thereafter therams I5, 20 and 20" are forcibly advanced following the teaching above whereby to force the metal to flow downwardly as viewed, and rightwardly and leftwardly toward the intersection of the channel C thereby extruding the leg 64 downwardly into the section 52 of the channel C. Preferably the rate of feed of the ram IE will be substantially double the rate of feed of each of the

mandrels

20 and 20" when, at the end of the forming strokes, the legs of the cross are sought to be of equal length. Mandrels 2i and 26" are held in fixed position as shown in Figure 9 throughout the whole forming stroke and the mandrel it is preferably permitted to fioat and/or is moved independently with respect to the ram l5 whereby to exert less than a drawing pressure on the end 65 of the extruded leg 64 during the essential formation of the leg 58. Preferably when the parts are in the position shown in Figure 9 the end of the mandrel l6 will not have complete forcible contact with the end 65 of the leg 66, but will be maintained closely adjacent thereto throughout the extrusion thereof.

When the rams i5, 20' and 20" approach the inner ends of their strokes the end of the extruded leg 64 will make contact with the shearing die 42. Whereupon additional forceful movement of the mandrel I6 shears out the central portion of the end 65 of the extruded leg 64 leaving that end open and right cylindrical. Additional force and motion from the rams may be applied if desired to fill out edges and comers while the mandrels fill the interior of the piece. Proper proportioning of the lengths of the head and shank branches of the 1' blank with respect to the respective and relative movements of the rams will produce the desired proportionate lengths of the respective legs of the finished cross. After withdrawal of the rams and mandrels the cross may be removed or ejected from the dies D, and the product in so-called finished form may thereafter be additionally worked as by appropriate sizing or socketing as suggested with respect to the T product, cf. Figures 3 and 4.

While I have stated my preference that the leg of the work piece aligned with the extruded branch to be formed be longer than the leg which lies transversely thereof, whereby the ram traveling in the direction of the extruded leg moves at a higher rate of speed and through a greater distance than the transversely moving ram or rams, I have found it practicable, when making equi-length legs in the finished product, to depart materially from this preferred practice at least through the range of relative leg lengths in the work piece from equality to making the transverse leg or legs of the work piece not substantially longer than desired in the finished product while making the leg that lies longitudinally of the extruded leg substantially twice its finished length. Where unequal leg lengths are sought in the finished product or where the extruded leg is desired to be of difierent diameter than the other legs, I prefer to proportion the leg lengths in the work piece and the rates and distances of ram movement in respect to the work to be done according to the precepts and preferences above stated.

While I have illustrated my invention with reference to 90 elbows, T's, etc., I have found it practicable to practice my invention with an= gled forms departing from right angles. My

i specific disclosure of right-angled forms of Work pieces and products should be taken here by way of illustration rather than limitation.

While I have found such materials as halfhard commercial copper and aluminum alloy tubing well suited to the practice of my invention at room temperatures, my invention is also adapted to the working of other materials such as steel at temperatures of desirable plastic matleability materially higher than room tempera him. One of the advantages of my invention is its adaptability to hot as well as cold working. In cold working I recognize that work hardening modifies the state of hardness of the material from work piece to finished product. Thus when I a straight blank is first worked to elbow form and then the elbow to T form I prefer that the straight piece be a little less than half hard so that the elbow will not be substtially greater than half hard when used as the work piece for forming the T. Similarly if the worked T is substantially harder than half hard I prefer to anneal it down to about a. state of half-hardness before using it as a work piece for making a cross.

While I have illustrated and described pre= ferred and modified forms and practices of my invention, modifications, changes and improvements therein will occur to those skilled in the art upon their understanding and practice thereof without departing from the spirit or scope of my invention or the underlying teachings hereof, and I do not care to be limited in the scope and effect of my patent to the Within preferred, illustrative and specifically described forms of my invention nor in any manner other than by the claims appended hereto.

I claim:

1. The method of making Ts from an elbowed work piece which consists in positioning the work piece in the angled channel of a forming die or T configuration with one leg of the work piece in the channel corresponding to the shank of the T and the other leg of the work piece in the channel corresponding to one of the head branches of the T, disposing and holding a mandrel in the leg or the work piece corresponding to the shank of the T throughout the length thereof, disposing a second mandrel in the other leg of the work piece with its end substantially in the bend of the work piece, applying extruding pressures to the ends of the work piece, and causing the metal to flow across the bend or the elbow in the direction of the head branch of the T to be formed while advancing the said second mandrel at substantially the same rate that said head branch is extruded.

2. The method of claim 1 in which said second mandrel is advanced at least in the beginning of its movement primarily by the gripping thereof by the wall of said other leg and movement therewith.

3. The method of claim 1 in which said second mandrel is advanced in the first instance by the influence of said other leg thereupon without the application of additional force thereto and is forcibly advanced at the end of its stroke to punch through the end of the extruded branch.

4. Mechanism for working an angled wrought tubular fitting to extrude an additional branch thereupon within a closed angled channel of a forming die, comprising hollow rams movable in converging angularly related directions and engageable with the ends of the fitting and adapted to exert extruding pressures thereupon, mandrels movable within said rams and engageable with the interior surfaces of .the branches of said fitting, one of said mandrels having its end within the fitting of substantially concave cylindrical form for close sliding contact with the side of the other mandrel, means for holding said one mandrel in a fixed position of close sliding contact with said other mandrel while the latter moves, means for moving said other mandrel an amount substantially equal to the combined extruding movements of said rams, and means for urging both said rams to move inwardly of said channel and compelling at least the ram associated with said other mandrel to move and extrude stock in the direction a? movement of said other mandrel.

5. Mechanism according to claim 4 in combination with a shearing die disposed to coact with a said other mandrel to shear out the end of the extruded branch.

6. Mechanism according to claim 4 in which the said other mandrel is free to have floating movement asinduced by the action of the stock of the fitting thereupon during the initial movement of the ram with which it is associated.

'7. The method of making a multi-legged angled wrought fitting from an angled blank having one leg less than the desired fitting and having a zone of intersection which consists in confining said blank externally and supporting the same internally while working the same to the shape desired in said fitting, feeding the stock of at least one of the legs of the angled blank into the said zone of intersection and substantially simultaneously causing the stock of said zone to fiow in a direction away from said zone to form a leg extending beyond said zone in the 12 direction of the axis of said one leg or said blank, said first named leg being longer than other leg or legs of said angled blank and stock being forced at the same time from all the legs into the extruded leg at rates of movement substantially proportional to the relative lengths of said legs. 8. The method of making a multi-legged angled wrought fitting from an angled blank having one leg less than the desired fitting and having a zone of intersection which consists in confining said blank in a cavity corresponding to the desired external form of the finished fitting and supporting said blank internally, feeding the stock of at least one of the legs of the angled blank into the said zone of intersection and substantially simultaneously causing the stock of said zone to fiow in a direction away from said zone to forn'fa leg extending beyond said zone in the direction of the axis of said one leg of said blank, supporting the extruded leg internally to predetermined internal form, limiting the extent of longitudinal fiow of said extruded leg in said cavity and thereafter forcing the stock toward said zone of intersection to tend to equalize the thickness of corresponding parts in the wall of the multi-legged product.

9. The method of making wrought T fittings from an elbowed work piece which consists in disposing a mandrel in each leg of the elbow, confining the piece externally except at the outside of the bend opposite one of the legs, exerting extruding pressure on the end of at least said last mentioned leg of the elbow and inducing the stock '0! the piece to flow beyond the bend thereof in Y the direction of the axis of said last mentioned leg to form the extruded leg of the T, externally confining said extruded leg to its desired form, and advancing the mandrel in said last mentioned leg transversely of the other mandrel and in the direction of the axis of said last mentioned leg with the fiow of stock beyond said bend in the extruded leg of the fitting.

10. The method of claim 9 with the step of simultaneously exerting extruding pressure on 4 the other leg of said piece to augment the fiow of stock into the extruded leg of the fitting.

11. The method of claim 10 with the step of supporting the stock of the bend internally except at the outside thereof adjacent said ex- 5g truded leg while said extruded leg is being formed.

12. The method of making a multi-legged angled wrought fitting from an angled blank having one leg less than the desired fitting and having a zone of intersection which consists in confining said blank externally except for a part of said intersection where the desired leg is to be formed, disposing a mandrel in each leg of the blank, exerting extruding pressure .at the end of at least one of the legs of the blank and causing metal to fiow from at least said one leg into said intersection and from said intersection in the direction of the axis of said one leg, advancing the mandrel in said one leg axially thereof and across said zone of intersection into and within the leg that is being extruded and there- 7 fitting from a three legged angled blank which by supporting the extruded leg internally during its extrusion, and externally confining said extruded leg to its desired form.

13. The method of making a wrought cross u it is worked to correspond to the desired internal form of the finished fitting, feeding stock from all three legs of said three legged angled blank into the zone of intersection of said legs and substantially simultaneously causing stock of said zone to fiow to form a fourth leg, the leg which lies diametrically opposite and in the direction of extrusion being longer than the legs which lie transversely thereof and stock being fed from all three legs at the same time and at rates substantially proportional to their relative lengths.

14. The method of making a multi-legged angled wrought fitting from an angled blank having one leg less than the desired fitting and having a zone of intersection which consists in confining said blank in a cavity complementary to the desired external form of wrought fitting, feeding the stock of at least one of the legs of the angled blank into the said zone of intersection and substantially simultaneously causing the stock of said zone to flow in a direction opposite said feeding leg and away from saidzone to form a leg extending beyond said zone in the direction of the axis of said feeding leg and substantially simultaneously advancing a mandrel from said feeding leg in the line of movement of the axis thereof through said zone into said extruded leg and supporting both said legs internally by said mandrel whilst metal is fed from one to the other.

15. The method of making a multi-legged angled wrought fitting from an angled work piece having an intersection and one leg less than desired in the angled fitting which consists in positioning the work piece in the angled channel of a forming die of configuration corresponding to the desired fitting with at least one leg of the work piece in a channel transverse the leg to be formed and another leg of the work piece in the channel aligned with the leg to be formed, disposing and holding a mandrel in the transverse leg of the work piece throughout the length thereof, disposing a second mandrel in the aligned leg of the work piece with its end substantially in the intersection of the work piece, applying extruding pressures to the ends of the work piece and causing the metal to flow across the intersection of the work piece in the direction of the aligned leg and the leg to be formed while advancing the said second mandrel in the extruded leg at substantially the same rate that said leg is extruded.

16. The method of claim 15 with the steps of continuing the extrusion of said extruded leg until the end thereof contacts a shearing die, and advancing said second mandrel through said die to open the end of said extruded leg.

17. The method of working an elbowed work piece to form a T fitting bv extruding a third leg from the bend of the elbov which consists in confining the work piece in angularly related portions of a T-shaped cavity having the form to be imparted to the exterior of the fitting whereby to support the work piece externally except at the outside of the bend opposite a first leg thereof, providing internal support for at least the less and the inside of the bend of the work piece,

exerting extruding pressure on the end of said first leg and moving the end of said leg toward the bend and flowing the stock through the bend into the portion of the cavity opposite said first leg to form the said third leg of the fitting in axial alignment with the first leg, substantially simultaneously advancing internal radial support for the third leg with the longitudinal growth of said leg without exerting substantial internal longitudinal pressure on the blind end of said third leg, and exerting pressure on the end of said second leg to facilitate the working of the piece.

18. Mechanism for working an angularly formed tubular blank having at least two original legs and an intersection therebetween to form by extrusion an extruded branch leg beyond the intersection in the direction of one original leg and transverse the other within a closed forming channel adapted to receive the angled blank and confine the extruded branch, comprising a first hollow ram adapted to engage the end of the leg opposite the branch to be extruded, a first mandrel movable within said ram and adapted to enter and substantially fill said leg, a second hollow ram adapted to engage the end of the other original leg, 9. second mandrel movable within said second ram and adapted to enter and substantially fill said other leg, the end of said second mandrel being concave and adapted to receive said first mandrel in transverse sliding contact in said intersection.

19. Mechanism for working an angled wrought tubular blank to extrude an additional branch thereupon within a closed angled channel of a forming die, comprising hollow ram movable in angularly transverse directions and engageable with the ends of the legs of the blank and adapted to exert extruding pressures thereupon, mandrels independently movable within said rams and engageable with the interior surfaces of the legs of said blank, one of said mandrels being movable in a path transverse the end of the other of said mandrels, both said rams and said one mandrel being simultaneously movable while said other mandrel is at rest.

PAUL D. WURZBURGER.

REFERENCES CITED The following references are of record in the