US2392925A - Apparatus for working metal - Google Patents

Description

0. KELLEHER APPARATUS FOR WORKING METAL Filed Nov. 16, 1942 4 Sheets-Sheet 1 INVENTOR.

Jan. 15, 1946. n. KELLEH'ER APPARATUSFOR WORKING METAL 4 Sheets-Sheet 2 Filed Nov. 16, 1942 IN VEN TOR.

Jan. 15, 1946.

Filed Nov. 16, 1942 4 Sheets-Sheet 3 Evy/9 INVEN TOR.

Jan. 15, 1946.

D. KELLEHER 2,392,925 APPARATUS FOR WORKING METAL Filed Nov. 16, 1942 4 Sheets-Sheet 4 INVENTOR.

76%;? M19 %%eq4 .m

Patented Jan. 15, 1946 2,392,925 arraanrns ron woao. METAL Daniel Kelleher, Strongsville, Qhio, assignor to The American Coach & Body Company, illeveland, Ohio, a corporation of Ohio Application November 16, 1942, Serial No. 465,727

- 7 Claims.

This invention is concerned with a system of working metal from a solid unit into a hollow form, the object being to improve the physical characteristics of the resultant article, both as to strength and uniformity of structure, and to reduce greatly the time and the cost of its transformation.

The present application relates toan appa-' ratus which I have developed for use in the working of hot metal and may be efliciently em- .ployed in the method of working metal which and the die and with the billet supported in an annular region while its central portion is unsupported; then forcibly shoving into the billet by rapid continuous motion a plunger of materially less diameter than the interior of the die, so that the billet is forced outwardly into contact with the wall of the die, and then, while the material of th billet is flowing, continuing the pressure to force the central portion of the billet downwardly and outwardly and upwardly in the annular region between the plunger and the oxidation of the surface and produce a uniform tubular article suitable for machining.

The apparatus shown in the drawings is adapted to carry out my method with great rapidity Fig. 6 is a detail of a portion of the stripper plate, shown in Figs. 2, 3 and 5; Figs. 7 to inclusive are views in section illustrating the object transformed by my apparatus, Fig. 7 showing the blank, Fig. 8 the result onsuch blank of the first operation of my apparatus, Fig. 9 the result by the second operation on the article of Fig. 8; Fig. 10 is a theoretic view of an article which may be produced by machining the transformed struc= ture illustrated in Fig. 9.

My apparatus is designed to take a solid cylin- I drical blank, such as shown at A in Fig. 7, and v transform it in a minimum of time into the structure B of Fig. 8, and then with a minimum of lost material into the structure shown at C in Fig. 9, the part D of that figure being the only waste material in the operation. The article C. is intended to illustrate any tubular member formed by my method which may thereafter be readily-machined into a useful article, for instance, into some such member as indicated at and without waste movement in the apparatus or excessive size thereof. This will be apparent from the following description.

\ In the drawings, Fig. 1 is a rear elevation partly sectional, of a portion of my apparatus; Fig. 2

is a vertical cross section of a portion thereof in planes as indicated by the offset line 2-2 on Fig. 1; Fig. 3 is a detail in plan of a stripper plate employed in the apparatus; Fig. 4 is a sectional plan of the apparatus on a plane indicated by the line 4-4 on Fig 1; Fig. 5 is a vertical section through the axes of a pair or dies andplungers employed in the apparatus, -as indicated by the line 5-5 on Fig. 4, but on a much larger scale;

E in Fig. 10, which designates a portion ofan artillery shell.

Referring to Fig. 1, id designates the base and ii and M a pair of uprights of a suitable vertically acting press. The upper portion of this press is not shown, but the view shows at 83 a ram vertically guided by the uprights ii and i2 and intended to be reciprocated by any wellknown mechanism. My transforming apparatus is carried by the base uprights and ram and operates on the blank designated A in Fig. '7 to transform it into the form shown at C in Fi 9 by means of two successive downward strokes of the ram.

Secured to the upper surface of the base i0 is a horizontal frame plate i5. Mounted in two vertically cylindrical recesses in the latter frame member are a pair of cylindrical housings 20 and 25 directly above which are a pair of externally cylindrical dies 30 and Ml. The housings extend above the frame member l5 and the dies are held in place in registration with such housings by a pair of clamping blocks i1 and l8, which have vertical semi-cylindrical recesses and embrace the two dies 30 and 40 and'the ex-' I The die 30. is adapted to receive the blank 5 of Fig. '7 and the plunger mechanism about to be described transforms the blank in that die into the form illustrated B in Fig. 8. The article B is then transferred to the die 40 and the downwardly acting plunger therein transforms it into .eter than the portion 3|.

the condition shown in Fig. 9. This will be apparent from the following description.

Rigidly mounted on the lower end of the ram I3 is an extension member 50, which in operation is rigidly attached to the ram and. may be considered as a part thereof, but which may be interchanged with other extensions in producing articles of different size or shape. To enable such interchange the extension 50 is slidable in ways ll formed in the ram l3 and is normally bolted in place as indicated by the bolt 5| in Fig. 2.

Formed in downwardly extending portions 50' of the ram extension 50 are guideways 52. In

w the top with an external flange l2 and in a lower region with a flange 13 and these flanges seat in recesses in the two blocks 60 with the result that the two plungers are rigidly carried by the sliding carriage. When the plungers are active I on the downstroke oi the ram they align axially with their respective dies, but near the upper stroke of the ram they are shifted toward the rear of the machine out of such registration by the lateral movement of the carriage, as hereinafter explained. I

The die 30, as shown in Figs. 2 and 5,-h as a cylindrical portion 3| leading downwardlyfrom the top of the die for the most of the height thereof and then a contracting conical portion 32 leading to a short cylindrical portion 33 of less diam- The conical surface continues below the cylindrical portion 33 as at 34, beneath which there is a third cylindrical portion 35. The junction of the short internal cylindrical portion 33 and the conical surface be- 4 low it provides an annular seat, and the blank A is of such diameter that when dropped into the die it may rest on its seat thereof, while clearing the internal wall of the die above the seat.

The plunger 10 has a downwardly extending cylindrical portion 15. then near the bottom a contracting conical portion IG'and a short cylindrical portion 11 below the conical portion.

Now when the plunger 10 is forced downwardly into the blank A in the die 30, the plunger enters the material of the blank and forces it first outwardly and then downwardly in the central region and upwardly into the annular region between the plunger and die, so that it comes into the condition shown at Fig. 8. Thus the article B is of greater external diameter than the blank A, and, as measured from the top, has a cylindrical well D, then an inclined reduced portion b-l, then a reduced cylindrical well b2, corresponding in form to the exterior of the plunger 15. The exterior of the article also has an annular rib b-3 caused by the recess 33 of the die and the article has an idle bottom portion b-l, these parts being obliterated in the subsequent operation.

The lower end of the die 3|! is closed by a plunger 2| idle during the forming operation but adapted to be raised to eject the cup-shaped article B. This plunger has an external flange 22 which furnishes'a substantial bottom to the plunger, while clearance in the housing above the flange allows aseaoas the upward movement of the plunger. The plunger extends downward in the form of a stem 24 by which it may be raised, by mechanism hereinafter explained.

The plunger 80 which'enters the die III has a major portion 8| in the form of a cylinder of greater diameter than that of the. portion I5 of the plunger I0 and below this'is a converging conical portion 82, below that a cylindrical por-.

tion 83 which may be substantially the same diameter as the extension "of the plunger 10 but is of greater length. The die 4|! is shown as having near the top a cylindrical portion 4| terminating ata horizontal annular wall; below this is a cylindrical portion 42 of reduced diameter, terminating at another horizontal annular wall; below this a reducing conical portion 43, and below this a cylindrical portion 4 4.

Siidably mounted in the housing is a tubular plunger 26 the upper end of which enters the die bore 44 and it has at its top a circular opening 21 adapted to receive the lowermost portion of the plunger 80. The upper end of this plunger 26 not only forms a bottom for the die, but by reason of its opening snugly registering with the pilot portion of the plunger all forms a die cooperating with such pilot, so that the bottom of the cup-shaped member B is sheared out and drops as the disc D (Fig. 9) into the bore of the plunger 26 and thus passes down idly to some receptacle not shown.

.The plunger 26 hasan external flange 2B seated in a recess in the housing 25, thus forming a bottom support for the plunger. The clearance in the housing above such flange allows the upward movement of this plunger. The same means (hereinafter described) which raises the plunger 2| to discharge the article B from the die 30, also raises the plunger 26 to discharge the article C from the die 40.

'When the solid cylindrical blank A of Fig. I is placed in the die and the plunger 10 forced downward into that blank it transforms it into the article shown at B in Fig. 8, the bottom of such article resting on the topof the discharging plunger 2|. Thereafter an upward movement of the plunger 2| may shove the article B upwardly a considerable distance in the die until the upper end projects well above the die, from which it may be removed, for subsequent opera-. tion in the die 40.

' When the article B has been placed in the die 4|! and the plunger forced downwardly, it forces the article outwardly into the larger cavity of the die 40 and at the same time the extension of the plunger BB-shears out the bottom of the article (indicatedat D in Fig. 9) which drops into the tubular bore of the plunger 26. This produces the tubular article 0 of Fig. 9.

To relieve the air pressure caused by the, movement of the plunger 80 into the member B, which at that time has a closed bottom, I provide a bore in the plunger which leads from the lower end upwardly axially and then outwardly at B6 to the exterior of the plunger. After the plunger is withdrawn the upward movement of the discharging plunger 26 in the die 40 shoves the finished article upwardly in the die and above it so that it may be conveniently removed.

If the plungers l0 and 80 were rigidly attached to the ram, it would be necessary to lift the ram approximately twice the height of the article be-' to get them out of the way of the dies very shortly I after they have reached above the top of the dies.

This mechanism is shown in Figs. 1 and 2. and

will now be described.

As heretofore mentioned, the plungers l and 80 are mounted in a carriage 6c slidable in ways 52 carried by the ram, these ways extending in the direction from front to back of the machine. Near its rear end the carriage is shown as provided on its upper face with a toothed rack 90 (Fig. 2) with which meshes a toothed segment 9! keyed to a shaft 92 mounted in brackets 83 carried, by the ram 13. The hub of the segment is provided with teeth 95 which mesh with the shift- .able rack 96 mounted in a housing 91 carried by the ram. Beyond the housing, the rack 96 carries a roller 98 occupyin a slot I00 in a bracket ml secured to the frame upright H. The slot Illa is vertical most of its height but near the upper portion is benttoward the ram. as shown at H13 in Fig. 2

When the roller 58 is in the vertical portion of the slot lot it holds the rack 96 in a position which holds the segment swung toward the left from that disclosed in Fig. 2, which holds the plungers directly over the axes of the dies, in position to coact on the same in the lowering movement of the ram. However, in the upward movement of the ram, after the plungers have cleared the dies, the roller 98 comes into the inclined portion of the slot, which shoves the rack 9-8 forwardly and hence moves the rack Bil rearwardly, thus moving the plungers toward the rear the ready removal upwardly of the articles formed. The discharging plunger 2i shoves the article B well above the die- 30 so that it may be either of them should remain around the plunger when elevated. This strippingdevice comprises primarily a horizontal plate I20 which surrounds the plungers and is supported by two pairs of hooked brackets l2i and in depending from the carriage 60. i

' When the plungers are being lowered the stripper plate rests on top of the dies and the plungers move downwardly through the plate. On the elevating movement of the plungers, if the article in either die clings to the plunger. such article lifts the stripper plate with the plunger until the stripper plate engages overhanging shoulders 128,121 carried by the base frame of themachine. Then the stripper plate can rise no higher and the plungers thereafter rising through the stripper plate withdraw themselves from the blocked article or articles.

The stripper plate I20, where it surrounds the plunger III is preferably provided at its under side with a recess I28 adapted to register with the cavity of the die 30 and provide an overflow space for the article being formed by that plunger. This is useful in case the blank is a trifle too long, and avoids the necessity of accuracy in the dimensions of the blank.

Where the stripper plate I20 coacts with the die 40, I prefer to make such portion a separate member which may then be made interchangeable and ofa desired die material difierent from the stripper plate itself. The separate member is shown as a disc i3ii, Figs. 5 and 6,'having a lower annular flange I31 and mounted in a correspondingly formed recess in the plate iill. Doubleheaded retaining buttons !32 are mounted in 0D- posed radial slots extending from said recess, the lower heads being cut away, as at I33 in Fig. 6, to allow the flange i3! to enter the recess. The disc I30 may then be locked in position in the plate I20 by applying a-screw driver to suitable slots inthe upper heads of' the buttons I32 and readily graspedby a pair of tongs and transferred to the die tit. Thereafter on the next upward stroke the plunger 25 shoves the article C above the die it where it may be freely removed by a pair of tongs.

For convenience, I have illustrated in Fig. 2 the controlling plate it! a bolted tight to the frame upright 92. However, if desired, that plate may be adjustably mounted on the frame member to enable the plungers to be positioned with extreme accuracy with reference to the dies.

turning them through 180, whereupon the remaining portions of the lower heads are caused to enter the notches Hit in the lower flange i3! and thus underhang the disc. The plate I20, as

shown in Fig. 5, then holds the buttons and the buttons retain the disc H30 in position. A half turn of the buttons, however, would free the 'disc I80 and enable it to be moved downwardly. This allows of the substitution of a different plate ltd having a difierent bottom formation to coact with p the top of the die cavity.

is in the normal lowering position it is axially aligned with the dowel post but on the upwardmovement it takes a course indicated at Y, Fig. 2. similar to the upward and rearward travel of the plunsers.

My experience indicates that ordinarily the are raised, I provide a stripping device which positively strips the articles 01! of the plungers, it

As a difierent form of die may be substituted,

it is desirable that the stripper plate over the.

the top end of the finished article. The clearance.

shown between the-top of'the die it and the bottom-of the stripper disc allows for an overflow of excess material, which can pass outwardly as a fin at the upper edge ofthe completed article. 65

I heretofore-mentioned the operation'of the discharging plungers 2| and 26 to shove the formed articles upwardly out of the dies. I prefer to make this operation pneumatic but controlled automatically by the operation of the ram, and such is the mechanism illustrated in the drawings. P rticularly in Fig. 1, which will now be described.

The two discharging plungersfl and 28 are mounted at their lower ends in a cross head I which is on the upper end of a piston rod. Ill

cylinder 3 supported by suitable frame-work I secured at the underside of the machine frame Ill. Suitable air valves, operated by the ram, control the admission of compressed air alternately to oppositeend of the cylinder with the corresponding venting of the other end, to raise and lower the two plunger-s 2| and 28.

One of the air valves is shown at I" in Fig. 1

surrounded by a spring tending to maintain the valve seated. Rocker arms I55 are provided for actuating these valves. Compression springs I56 tend to hold the rocker arms in their lowermost position as shown in Fig. 1.

Secured to the ram is a depending bar I having a shoulder lil which in the lowermost position of the ram is adapted to swing by gravity beneath a pin I58 on the rocker, shown with the duplicate thereof behind it. On the downward stroke of the ram until it reaches it lowermost position the valves connect the supplyof compressed air from the 'pipe I85 to the pipe I68 leadingv to the upper end of the cylinder while venting the lower end, thus holding the plungers 2| and 26 in their lowermost position. when, however, the ram reachesits lowermost position the shoulder I8! has passed below the pin I58 andswings underneath that pin, so that as the ram is being elevated the bar I50 swings the rockers I55 to reverse the valves so that the air from the pipe IE is now connected with a pipe I61- leading "to the bottom of the cylinderand the pipe I66 from the top is connected with a vent I68. According the air pressure immediately shoves upward on the piston in the cylinder and thus raises the two plungers 2| and 26 to shove the formed articles upwardly and beyond their leading upwardly from a piston I" in a vertical respective dies, just as the ram is reaching the top of its stroke.

The upward movement of the piston rod Hi swings a rock lever I10, pivoted to the frame I and loosely pinned to the piston rod, to lower the outer end of that lever. Such outer end is conuected by a link I12 with a'leve'r I13 pivoted at I'll to the frame member II. This lowering movement brings the free end of the lever I'II against the depending bar- IBII (as indicated by broken lines I13 in Fig. 1) and cams that bar away from the pin I58 on the rockers i55. This frees the rockers and the spring I returns them 1 to normal position, thus venting the lower end of the cylinder I43 and turning the compressed air into the upper end.

It will be seen from the description given that each cycle of operation oi my apparatus is autoerratic and may be performed with great rapidity. The hot blank is placed by a pair of tongs in the die 30, and the operator steps on a pedal or otherwise causes the press to'begiri operation. The plunger 10 forms it into the article B, the discharging plunger 2| lifts that article part way from the die as the plunger 10 recedes and is completing its upward stroke and the ram comesv to rest at the completion of its cycle. The hot article is then readily grasped by a pair of tongs and placed in the die ll! ready for operation by the plunger so on the downstrtfir cycle is initiated. Then on the upstroke the completed article is raised by the plunger 2! sums. when the next fibres in the direction of the length of the article ciently so that the operator may conveniently remove it by tongs.

It has been convenient to describe the operation of the apparatus as forming the completed article on two successive strokes, the first stroke converting the billet into the cup-shaped member and the second stroke converting such cupshaped member into the tubular form. It is to be understood, however, that if desired, these two operations may be performed simultaneously, the first plunger forming the cup-shaped member at the same time that the second plunger produces the complete form from a cup-shaped member made on the preceding stroke.

As the apparatus operates intermittently, the

starting of each cycle being controlled by theoperator, a single operator may place the billet in the first die, remove the cup-shaped member from that die and place it in the seconddie and -remove the completed member'from the second as would result with a low heat or a slow operation or a re-heating of the article between plunging actions.

By my operation of forming the article, the plunger pressing it from the center outwardly and upwardly produces an article of very uniform texture. The grain structure at the center or the blank is somewhat different from that in the outer regions and the plunger actions tends to distribute the molecules and produces uniformity. Moreover, acting in one direction lengthwise of the blank, it tends to elongate the (as indicated bythe longitudinal lines in Figs. 8 and 9) and thus give great strength tothe article.

The texture of the article produced is more compact and firm than in the case of a steel casting; is more uniform than a forging, and the article may be made decidedly quicker than if ,the cavity were drilled in a previously formed blank, and with a much less waste of material.

With my operation the only material wasted is the small disc at the lower end of the cavity, indicated at D in Fig. 9. My experience indicates that such waste of material is only about oneelghth that which would exist it the same article were made by a drilling operation from a solid block. Moreover the article may be made in not over a fourth of the time required for such drilling' operation. Accordingly. it results that by my method of manufacture, I am able to produce, in very much less time and at less expense,'a tubular article which is intrinsically better than a correspondingly shaped article made by the usual methods.

At the start one severs the bar into billets 3 long. These are placed in a non-oxidizing atmosphere in a furnace and subjected to a soaking heat of about 1940 F. until the billets are thoroughly saturated at such temperature. In the meantime, the dies of the apparatus have been heated, for instance, by the application of a gas flame, to a temperature of about 900 F.

The hot billet is then placed in the firse die of the machine and rests on the annular ledge therein, so that it stands axially of the die-with its cylindrical surface spaced from the die wall approximately Now, the machine is started, and the plunger, coming down and contacting with the billet, forces it outwardly and at the same time gradually downwardly into the restricting space provided by the conical lower portion of the die. This provision for the billet moving downwardly to a certain extent, while the plunger moves downwardly, acts as a cushion or shock absorber to the machine and prevents too sudden a stress on the mechanism and also results in a pressing action rather than a hammering action on the billet.

After the downward pressuref'of the plunger has seated the billet against the movable bottom of the die and has forced the wall of the billet into contact with the wall of the die, the continued movement of the plunger displaces the center portion of the billet and distributes the metal thereof through the remaining annular portion. The entire action from the time the plunger engages the top of the billet until it has completed its downward stroke requires only two or three seconds. This rapid operation maintains the metal flowing from start to finish, and there is not time for oxidation. The extrusion by this first operation refines the metal, resulting in a wall of very uniform characteristics and increased a strength.

Now when the cup-shaped article discharged from the first die is quickly transferred to the second die, the absence of any reheating, and action by the second die at nearly the same temperature are important in insuring uniformity of structure. The working in the second die reduces the grain size and improves the structure causing a further increase of tensile strength.

The product produced by my method is quite different from that of the ordinary forging or upsetting operations which require a succession of blows, each 'successiveblow being at a different heat. thus producing varying grain structure not easily treated to obtain uniform results. These factors of single heating, rapid operation, and extrusion and followed by press forging all con tribute to the strength and uniformity of the product structure. These are important characteristics for the proper and rapid machining of the product to produce the ultimate article desired.

The present invention possesses important advantages over methods previously practiced in manufacturing the same article, particularly where the article was previously machined from bar stock. Heretofore, in such practice, it was necessaryto start with a bar weighing about .eight pounds to obtain a finished product weigh-' ing about four pounds.

a substantial saving in wear on the cutting tools,

Additionally, there is because the machining required at the completion of the pressing operation, according to the present invention. is negligible as compared to that required for machining the article out of bar stock. Moreover, I have found that by working the metal under pressure, a more uniform grain structure is obtained, thus facilitating the subsequent machining operation, whereas in bar stock, the outersurface usually has a denser or tougher grain structure than-the interior portion, which has a detrimental effect upon the rateat which the metal can be removed by the cutting tool.

I claim:

1. ,In an apparatus for forming hollow articles,

the combination of .a frame havinga bed and guiding members, a ram reciprocally guided by said members, a carriage slidable on the ram and having a rack, a gear member meshing with the rack, a second rack meshing with the gear memher and a guide carried by the frame and coacting with the second rack and having a guiding surface parallel with the movement of the ram to hold the carriage stationary and another guiding surface at'an acute angle to the surface first mentioned to cause the carriage to shift on the ram, and a coacting die and plunger, one mounted on the bed and the other on the carriage.

2. In an apparatus for making hollow articles, the combination of a tubular die, a discharging hollow plunger entering the die and forming an annular bottom therefor, a forming plunger adapted to enter the die and having a reduced end adapted to enter the opening at the upper end of the discharging plunger to shear out the bottom of a cup-like article within the die which thus passes into the hollow of the discharging plunger, the apparatus having a bed and a ram reciprocable toward and from the bed, one of which members carries the die and the other the plunger.

3. In an apparatus for forming a tubular article from a cup-shaped article, the combination of a die adapted to embrace the cup-shaped article, means forming a bottom for the die and having an opening through it, a plunger adapted to enter the die and progress within it and having on its end portion a pilot adapted to slidably enter the open end of the die bottom, and a ventilation flue within the plunger leading from the lower end inwardly and along the plunger and discharging beyond the die, and means for causing the plunger to enter the cup-shaped article in the die and punch out the bottom thereof.

- ing the bottoms of the cavities thereof, a cross head connecting said two discharging plungers, a cylinder, a piston within the cylinder having its rod connected with the cross head, and means for automatically supplying fluid under pressure to the cylinder as the ram recedes from the bed to push the formed articles out of the respective dies.

5. An apparatus for forming hollow articles comprising a bed with upright guideways, a reciprocable ram mounted in the guideways, a cavitary die carried by the bed, a carriage mounted on the ram, a depending plunger mounted in the carriage and adapted to coact with the die, means for moving the carriage as the ram recedes upwardl to shift the plunger laterally, a ,movable stripper. plate surrounding the plunger. 9. supporting hook depending from the carriage and loosely engaging the underside of the stripper plate, whereby the stripper plate may move downwardly with the die plunger until the stripper plate stops at the top of the die after which the plunger may move through it, and whereby it the article in the die adheres to the plunger on the recession thereof, said article will lift-the stripper plate with it, and an abutment carried by the frame and overhanging the stripper plate to limit a the upward movement thereof and enable the plunger to move upwardly through the stripper plate and strip the article.

6. In an apparatus or the class described, the

combination, with a bed and frame and a reciprocating ram carried by the frame and movable toward and from the bed, of a die and a coacting plunger, one carried by the bed and the other by the ram, a stripping unit embracing the plunger and means for removably mounting it in a stripper plate, whereby diflerent units may be substituted, and means for so supporting the stripper plate that it may move with the plunger, and means for stopping the movement of the stripper plate independent of the movement or the plunger.

7. The combination of a bed, a hollow die carried thereby having an upwardly facing cavity, a, reciprocable ram above the bed, a plunger extendingdownwardly from the ram and adapted to enter the die, a stripper plate loosely embracing the plunger, means on the ram tor loosely supporting the stripper plate and adapted to descend independently of the plate when the plate engages the work, and means carried by the bed to form an abutment limiting the upward movement of the stripper plate when it has been raised by the work adhering to the rising plunger. I

DANIEL KELLEHER.

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