US3908430A - Apparatus for cold-forming metal workpieces - Google Patents

Abstract

A setup for use in a press for cold-forming metal parts, such as tripods of universal joints having a central body and radially projecting portions, from a cylindrical billet. A first setup is provided for forming an intermediate workpiece which may then be finished in a second setup. In the first set-up the die sectors which make up the die are mounted on rams which are slidably mounted on slotted members between a spaced apart position when the press piston is in its raised position and a clamped together position by means of a toggle mechanism. Punches are provided on the table and the piston which compress the starting billet thereby extruding the metal into channels in each of the die sectors. In the second setup upper and lower die halves are carried respectively by the piston and the table of the press. The die halves have channels adapted to receive the various portions of an intermediate workpiece. Vertical and horizontal punches are provided for finishing various recesses and surfaces of the intermediate workpiece. The die halves are clamped together without working force of the press which may reach 100200 metric tons.

Description

United States Patent n 1 Orain 1 3,908,430 Sept. 30, 1975 APPARATUS FOR COLD-FORMING METAL WORKPIECES Michel Orain, Conflans-Sainte-Honorine. France [75] Inventor:

[73] Assignee: Societe Anonyme: Glaenzer Spicer,

Poissy, France -221 Filed: Apr. 5, 1974 [21] Appl. No.: 458,227

Primary Eruminer-Richard .l. Hcrbst Attorney, Agent. or Firm-Baldwin. Wight & Brown [57] ABSTRACT A setup for use in a press for cold-forming metal parts. such as tripods of universal joints having a central body and radially projecting portions, from a cylindrical billet. A first setup is provided for forming an intermediate workpiece which may then be finished in a second setup. in the first set-up the die sectors which make up the die are mounted on rams which are slidably mounted on slotted members between a spaced apart position when the press piston is in its raised position and a clamped together position by means of a toggle mechanism. Punches are provided on the table and the piston which compress the starting billet thereby extruding the metal into channels in each of the die sectors. In the second setup upper and lower die halves are carried respectively by the piston and the table of the press. The die halves have channels adapted to receive the various portions of an intermediate workpiece. Vertical and horizontal punches are provided for finishing various recesses and surfaces of the intermediate workpiece. The die halves are clamped together without working force of the press which may reach 100-200 metric tons.

12 Claims, 30 Drawing Figures U.S. Patent Sept. 30,1975 Sheet 1 of 9 3,908,430 I I 3 3 FIG.1 H62 U.S. Patent Sept. 30,1975Sheet 2 of 9 3,908,430

US. Patent Sept. 30, 975Sheet 3 of9 3,908,430

US. Patent Sept. 30,1975

Sheet 4 of 9 US. Patent Sept. 30,1975 Sheet50f 9 3,908,430

US. Patent Sept. 30,1975 Sheet6 0f9 3,908,430

FlG.23

US. Patent Sept. 30,1975

Sheet 70f 9 U.S. Patent Sept. 30,1975 Sheet9 f9 3,908,430

FIG.25 r

FIG.26

FlG.29 D

g. |=|e.27Q g x S 3 APPARATUS FOR COLD-FORMING METAL WORKPIECES DETAILED DESCRIPTION OF THE INVENTION The present invention relates to cold-forming metal workpieces, particularly steel workpieces, for the manufacture of parts without removing material.

Known methods of cold-forming steel and other hard metals, such as extrusion, sizing, drawing, etc., apply to pieces of revolution having a constant or substantially constant cross-sections varying within narrow limits. Such pieces or parts could in fact have protuberances, notches, serrations which make up only a small percentage of the total volume of the part and are only slight relative projections.

The present invention proposes the cold-forming of cylindrical or substantially cylindrical billets, a family of workpieces which up till now have been roughed out by hot die then machined over their entire surface by removing metal chips with turning mills, drills, broaches, milling cutters, etc. This family of workpieces comprises those having a main axis and substantial radially projecting portions more or less equally spaced around the main axis.

A more particular aspect of the invention consists in apparatus which enables this result to be achieved by producing a piece such as an intermediate rough shape workpiece from a parting billet or a desired final piece from the same starting billet or from said rough shape workpiece.

The apparatus according to the invention essentially comprises, on the one hand, a first assembly including a multipart die adapted to form, when bringing the dieparts together, a cavity which corresponds to the shape of the piece to be formed, this cavity having a central chamber and radially projecting channels adapted to receive corresponding portions of the piece to be formed and, on the other hand, a second assembly including punches adapted 'to extend inside said die through openings specially agenced in said die parts for effecting deformations of the contents thereof, the component parts of these assemblies being respectively carried by the press piston and table and the component parts of the other assembly being carried by rams or blocks sliding in a parallel direction with the axis of the press in oblique guide-slots arranged about the axis of the piston between the upper and lower plate members urged toward each other, said blocks being arranged to be driven by the piston along at least part of its work stroke after meeting in their resultant movement in their guide-slots to approach one another, this movement toward one another following the closing movement of the die when the parts thereof are carried by the press piston and table and the guide-slots supporting the punches which then penetrate into the closed die, in preceding this penetration movement when the punches are supported by the press piston and table and the blocks support the component parts of the die.

In case of starting with a cylindrical billet to obtain an intermediate workpiece or a nearly finished workpiece, if need be, the die preferably comprising as many sectors as there are radial projections to be formed on the central body of the piece, a transverse boring in the direction of plane extending radially with respect to the axis of displacement of the press piston being provided in each die sector and opening in a narrowed portion forming an extrusion throat on a part-cylindrical cavity, the combination of the part-cylindrical cavities of each of the die sectors forms a cavity coaxial with the press piston, the cavity being open at its ends, adapted to receive the starting billet, and having a section along the axis immediately adjacent to the openings which is at least in part the section of the central body of the piece to be obtained, each die sector being carried by an obliquely sliding block, while two punches respectively borne by the press piston and the press table along the axis of the piston are adapted to penetrate into said cavity, so compressing the starting billet.

In this case, each die-sector-carrying block is preferably connected to the press piston by a toggle joint comprising two levers pivoted to each other, one of the levers also being pivoted on the block and the other lever also being pivoted on a socket slidably mounted on the press piston with a compression spring interposed therebetween for urging the socket towards the blocks, the sliding socket being arranged to bear against the blocks and displace them along their guide-rods during the downward movement of the piston, means being provided for preventing the common pivot point of the levers of the toggle joint to move substantially away from the position in which the distance between the sliding socket and the blocks is at its maximum, and then enabling this common pivot point to move away from the position in order to come in contact under the retaining abutment when the die sectors are moved into contact with one another for clamping the die sectors.

In case of finishing an intermediate workpiece, the die is preferably composed with two die halves borne respectively by the press piston and the press table and adapted to receive the die workpiece in an array of radially extending channels disposed in the faces of the half-dies adapted to come into contact with each other, punches adapted to penetrate into the channels being borne by blocks being adapted to slide parallel to the axis of the piston along two oblique guide-slots, the half-dies being supported by members movable along the axis of the press piston and connected, for the upper half-die to the piston to an interposed compression spring urging the upper half-die towards the lower .half-die, and for the lower half-die, to means enabling the sliding movement of the shaft in the table in response to the piston until the position in which the shaft is secured against movement, by means of horizontal cross bars and vertical tie rods, to a member adapted to abut against an element integral with the press piston during the forming of the piston.

The device according to the invention enables, as it will be shown hereinafter, a manufacture of pieces by cold deformation without removing material under conditions which, compared to conventional methods, have a great number of advantages which can be resumed as follows:

1. Elimination of die forging a rough workpiece: according to the invention, the raw material is employed directly as round bars sheared off to the desired length in order to obtain the starting billets;

2. Elimination of all losses of metal, since the weight of the ultimate piece is equal to the weight of the billet;

3. Elimination of numerous machining operations: drilling, facing, boring, lathe work, which are each repeated as many times as the number of radial axes;

Indeed, according to the invention, the portions along the main axis and the radial axes are obtained si multaneously.

4. Elimination of adjustment and checking operations associated with machining since the cold-forming tools yield very uniform dimensions as long as they are in use. The only intervention necessary is to put them out of service.

5. High speed manufacture: the production rate of such presses is in the range of 500 1000 pieces per hour for the proposed application i.e., about to IO times greater than the production rates with chip re moval machine tools;

6. Greatly reduced investments since one or two presses are sufficient to transform a cylindrical billet into an achieved piece and since the production rate is increased;

7. The quality of the pieces produced is higher than by conventional methods. Indeed:

a. the grain structure is optimum;

b. the condition of the surfaces is excellent so that in many cases fine griding may be dispensed with;

c. the accuracy of certain dimensions is obtained more easily than with machine tools working at very high production rates;

d. the evolutive shapes of the produced pieces such as adjusting by fillets of various surface types are ensured with perfect constancy and without scratching or tearing out as it occurs with conventional machining methods when the cutting tools start to wear out.

Various examples of parts which may be obtained according to the invention and apparatus for producing such pieces are illustrated in the accompanying drawings, in which:

FIG. 1 is an elevational side view with cutaway portions of a so-called tripod or three-arm member of a constant velocity universal joint produced according to conventional machining methods;

FIG. 2 is a cross-sectional view taken on the line II-II in FIG. 1;

FIG. 3 is a detail on a larger scale of FIG. 2;

FIG. 4 is a view corresponding to FIG. 1 of an intermediate rough workpiece from which the piece shown in FIG. 1 is produced;

FIG. 5 is a cross-sectional view taken on the line VV in FIG. 4;

FIG. 6 is a view similar to that of FIG. 1 of the same part when it is obtained according to the invention;

FIG. 7 is a cross-sectional view taken on the line VII- -VII in FIG. 6;

FIG. 8 is a detail on a larger scale of a piece of FIG.

FIG. 9 shows the steel billet which is the raw material piece for producing the piece shown in FIGS. 6 and 7;

FIG. 10 is a side elevational view with cutaway portions along the axis of one of the arms of the tripod of an intermediary workpiece, obtained according to the invention, before the finishing pass at the end of which the piece shown in FIGS. 6 and 7 is obtained;

FIG. 11 is a vertical cross-sectional view of a press with a tool setup according to the invention for producing the rough workpiece shown in FIG. 10, at the left in FIG. 11 the press is shown at the end of its roughing out stroke;

FIG. 12 is a cross-sectional view taken on the line XIIXII in FIG. 11;

FIG. 13 is a plan view of a guide-rod which is part of the tool setup for the press shown in FIGS. 11 and 12;

FIG. 14 is a cross-sectional view taken on the line XIV-XIV of FIG. 13;

FIG. '15 is a view partly in elevation and partly in vertical section of a press with a setup for finishing the piece of FIGS. 6 and 7, the press being shown in its raised position before introducing an intermediate workpiece to be finished;

FIG. 6 is a cross-sectional view taken on the line XVIXVI in FIG. 15;

FIG. 17 is a detail showing the linkage supporting the lower part of the die in the press tooled up according to FIG. 15 in the extended position of the linkage;

FIG. 18 is a view, on a larger scale, of the tooled-up press shown in FIG. 15;

FIG. 19 is a plan view of the lower part of the die of the tooledup press of FIG. 15;

FIG. 20 is a cross-sectional view taken on the line XXXX in FIG. 19;

FIG. 21 is a plan view of a block which is part of the tooled-up press in FIG. 15;

FIG. 22 is a cross sectional view taken on line XXII- XXII in FIG. 21;

FIG. 23 is a vertical sectional view of setup for forming in grooves of part-circular section with sperical ends, in a generally cylindrical piece;

FIG. 24 is a schematic plan view of a detail of FIG. 23;

FIG. 25 is a front elevation view of another kind of part which could be formed according to the invention;

FIG. 26 is side elevation view with a portion in crosssection taken on the line XXVIXXVI in FIG. 25;

FIGS. 27 and 28 are views similar to those of FIGS. 24 and 25 for an alternative type of tripod which can be made according to the invention;

FIG. 29 is a longitudinal cross-sectional view of the starting billet used to obtain the tripod of FIGS. 28 and 29; and

FIG. 30 is an elevation view with cutaway portions of a four-arm cross-piece ofa universal joint which can be made according to the invention.

First of all, we shall consider the machining of a socalled tripod which is a component part of a constant velocity universal joint for driving the wheels of a frontwheel drive automobile. This piece comprises a central body 1 carrying threearms 2, the axes of the arms being located in a single plane and angularly spaced from one another. Rollers (not shown) are adapted to be mounted for rotation on the arms and sliding along the axes of the arms. A cylindrical cavity 3 (see FIG. 3) is provided in the end of each arm for securing the tripod in a bore coaxial to the stub axle of a wheel of the vehicle with a stud provided in the stub axle for that purpose. A blind bore 4 is provided in the central body 1, aface 5 being provided around the open end of a blind bore 4 and a spherical dome 6 at the end of the blind bore 4 opposite theface 5, the axes of the arms intersect at a point in line with the center of the spherical dome 6. The blind bore 4 and the spherical dome 6 are provided to maintain the tripod axially while giving it freedom to oscillate about the above-mentioned point of intersection.

The manufacture of such a tripod by conventional machining comprises the following steps:

a. Die forging a rough workpiece with dimensions withone one millimeter of the final dimensions, the workpiece thus produced being shown in FIGS. 4 and 5;

b. Scaling by shotblasting and then checking the workpiece before passing it on to a machine tool;

c. Drilling a rough central hole 4 and spot-facing the open end thereof;

d. Milling the outside of the arms to the desired length and then milling flats 7;

e. Roughing out and finishing threebores 3 with their countersinks or chamfers 8 (FIG. 3) and three centers or recesses 9 which in association with theopposed bores 3 at the ends of the arms enable the turning and the subsequent grinding of the arms;

f. Consecutively turning the threearms 2 withchamfers 10 at their free ends; and

g. Turning the spherical dome 6 and fine grinding it.

The same tripod piece may be turned out as shown in FIGS. 6-8 by a tool setup according to the invention in only two steps starting with a cylindrical billet as shown in FIG. 9 obtained by shearing off a bar of annealed steel straight fromthe steelworks.

In FIGS. 6-8 pieces similar to the pieces in FIGS. 1-3 are designated by the same reference numerals plus ten.

Not only are the steps of manufacture, and therefore the production costs of such a piece, considerably reduced compared to what was possible with the former method, but in addition, the pieces formed by the tool setup according to the invention are improved from the point of view of mechanical strength owing to the fact that the bores of theholes 13 at the ends of the arms and thecentral bore 14 in thecentral body 11 of the piece are connected to their substantiallyflat bottoms 21 and 22, respectively, byfillets 23 and 24; similarly, thefaces 25 at the free ends of the arms are connected to the outer surface of their respective arms and lateral surface of thebores 13 by the rounds or curved connectingzones 18 and which replace thechamfers 8 and 10; and finally, the contours of the centers or recesses 19 are also rounded. It is known that fillets and rounds of the above types avoid stress concentrations which are caused by presence of more or less sharp angles. Further, therounds 18 at the open ends of thebores 13 at the free ends of the arms improve the quality of the force fit of the ends of the arms in corresponding stud pins in the bore of the stub axle to be driven. Such rounds and fillets would be very difiicult to mass produce by conventional methods.

Moreover, the accuracy and quality of the surfaces of thebores 13 in the ends of the arms as well as that of thecentral bore 14 are very much better than those mass produced by chip removal and do not require finishing steps. Thespherical dome 16 is also obtained in a single pass and does not need subsequent fine grinding. Only the grinding of the arms after quenching the piece may be necessary, which is the reason for the provision of thecenters 19.

Finally, as a complementary advantage, the grain structure of the steel resulting from forming with the setup according to the invention is optimal and also makes the piece more reliable and improves its performance.

Thus, as previously indicated, the piece in question is obtained by means of a tool setup according to the invention in only two passes, viz., a pass for forming a rough workpiece such as shown in FIG. 10 having acentral body 11, threearms 12 and thecentral bore 14 in thebody 11, and a second pass for forming thebores 13 in the ends of the arms, thecenters 19 and thespherical dome 16.

The first pass is carried out with the tool setup shown in FIGS. 11-14.

This tool setup is mounted in a press, only thepiston 26 and the table 27 of the press being shown. The metal forming or working parts of the setup comprise a die formed in three identical sectors or quadrants (see FIG. 12 in particular) and twopunches 29 and 30.

Each of thesectors 28 making up the die is fixed by a bolt 31 to ablock 32 having a T-head 33 which is engaged in an inclined guide-slot 34 formed in a slottedmember 35 having aconcave face 36 on which theblock 33 is carried, theconcave face 36 being inclined parallel to the guide-slot 34 at an angle a of about 12 from the vertical. The slottedmembers 35 are held at their lower ends in a circular recess in aplate member 37 and at their upper ends in a corresponding recess in amovable plate member 38. The recess in the movable plate member also has ashoulder 39 against which the heads of the slottedmembers 35 bear. Themovable plate members 37 and 38 are urged toward each other by thetie bolt 40 clamping the slottedmember 35 therebetween. The slottedmembers 35 are arranged so that their median planes make 120 angles relative to one another, the spacing between the slot members being maintained byspacers 41. Eachblock 32 carries a yoke 42 on which apin 43 is pivotally mounted and retained thereon by a washer 44 which is retained longitudinally by a cotter pin 45. The block also has apawl 46 comprising at its upper end a part-cylindrical surface 46a, A centered, having a radius R and alug 47, on which a telescopic link is pivotally mounted, formed of ayoke 48 pivotally mounted on alug 47 about apin 49 which is extended by a teat screw 50 and a similar member comprising a teat screw 51 extending ayoke 52 which pivots about apin 53 in anotch 54 at a pcriphery of awing 55 which is slidably mounted on thepiston column 56 which is in threaded engagement with theextension 57 of the piston of thepress 26. The two teat screws 50 and 51 of the telescopic link 48-52 are connected together by a threadedsleeve 58 for adjusting the length of the telescopic link. The uppercylindrical surface 46a of thepawl 46 is adapted to be engaged, as indicated hereinafter, under a bearingsurface 59 along the underside of anabutment member 60 which is held in the recess in theplate member 38 above the guide-slots 35.

The lower end of a slidingsleeve 55 is in threaded engagement with a threaded adjustment ring 6 which comes into abutment, through an interposedring 62 acting as a liner, with ashoulder 63 on thewing 55, theadjustment ring 61 being adapted to come into abutment with the upper face of the yokes 42 on theblocks 52 at the end of the stroke of the press, as will be indicated hereinafter.

An annularflanged collar 64 engages the lower end of thepiston column 56 and is held under the piston column bybolts 65, the outer surface of thecollar 64 is shaped to be received, as will be described hereinafter, inside an annular centeringmember 66 carried by the yokes 42 on theblocks 32. Aspacer washer 68 used as a liner is maintained under the annularflanged member 64 byscrews 67 and is adapted to abut against the upper surface of thedie sectors 28 at the end of the press stroke, as will be described hereinafter.

The annularflanged collar 64 also maintains thepunch 29 under the lower end of thepiston column 56.

Further, acompression spring 69 is disposed between ashoulder 70 which is formed on theextension 57 of the piston and a shoulder 71 formed in the slidingsleeve 55 abovenotches 54 receiving the end of the telescopic link 4852. (To simplify FIG. 11 the telescopic link is shown very schematically on the left-hand side of FIG. 11).

Theannular plate member 37 carries the slottedmembers 35. A tappedhole 72 is formed in center of theplate member 37 and a threaded socket orsleeve 73 threadedly engages the tappedhole 72 and has anaxial bore 74 in which acolumn 75, fastened to the press table 27 by abolt 76, is received. Three compression springs 77 are disposed between theplate member 37 and the press table 27 and spaced 120 from one another and bear against the underside of theplate mem ber 37 through theadjustment spacer 78. The spring force or flexibility of the combination of three compression springs 77 is equal to that of thespring 69 interposed between thepiston extension 57 and the slidingsleeve 55 which slides along theplunger column 56. The end of the up-stroke of theplate member 37 is determined by the position of thetie bolts 79 threadably engaging the table 27 of the press.

Acentral recess 80 is provided in the upper end of thecolumn 75 in which the butt end of thelower punch 30 is received, thelower punch 30 being maintained by aring 81 fastened to the upper end of thecolumn 75 by bolts 82. Another ring 83 overlies thering 81 and is held byscrews 84, this ring 83 functioning as a liner on which thesectors 28 of the die are supported at the end of the piston stroke, as will be described below.

Each diesector 28 is of generally pentagonal shape with a flat base adapted to come into engagement with its associatedblock 32 and opposite the flat base two faces 89 making 30 angles with the base, whereby thefaces 89 of adjacent die sectors come into contact against one another along planes spaced by 120 when brought together. A cylindrical chamber, orcavity 90 is formed by the portions connecting the inclined faces 89 of each of the die sectors, the diameter of the cylindrical chamber ofcavity 90 corresponding to that of the central body 1 of the piece to be formed (FIGS. 6, 7 and 9). Thecylindrical chamber 90 communicating with acylindrical boring 91 the axis of which perpendicular to the common vertical axis of the three diesectors 28 in their closed position, is located along the median plane of the rectangular base of each die sector. This boring 91 comprises at its end, communicating with thechamber 90, a narrowed portion formed a die throat and at their opposite ends a tappedportion 93 in which the bolt 31 is threadably engaged, the end 310 of the bolt 31 acting as a stop as will be described hereinafter.

Theupper punch 29 and thelower punch 30, the other elements of the tool setup in combination with thedie sectors 28, have diameters corresponding to thecylindrical chamber 90 between three diesectors 28 when they are brought together. The end face 94 of theupper punch 29 has anaxial projection 95, the outer diameter of which is equal to the inner diameter of thecentral bore 14 in the piece body 11 (FIGS. 6, 7 and and the length of which is equal to the depth of the bore. Theaxial extension 95 is connected to theend face 94 of thepunch 29 by a fillet and its end ridge is rounded to correspond to the rounds which must be provided at the open end of thebore 14 and the connecting zone between the lateral walls and the bottom of the bore. As for the lower punch, it has aflat face 96 at its upper end.

In order to obtain the intermediate workpiece as shown in FIG. 10 with the tool setup as described above, the operation is as follows:

When the press is opened, i.e., thepress piston 26 in its extreme raised position, the die blocks 32 are also in their raised position. The die blocks are brought to their raised position by the linkage comprising the telescopic links 4852 and thepawls 46, thepawls 46 then being substantially vertical and in abutment against a ring fastened byscrews 86 to anannular flange 87 which in turn is fastened byscrews 88 to the upper face of theupper plate member 38 for maintaining the slottedmembers 35. The diesectors 28 are then farthest from one another left-hand side of FIG. 11

The cylindrical starting billet having a diameter equal to that of the axial chamber (FIG. 9) is then placed on theupper face 96 of the lower punch 30 (which may be slightly magnetized to ensure the billet being held in a vertical position). The billet may also be introduced a little later, just before the closing of thedie sectors 28, as will be described hereinafter.

Thepress piston 26 then starts its downward movement which drives the telescopic links 4852 downwardly with thepawls 46 and theblocks 32 and theirdie sectors 28. As theblocks 32 slide along the inclined surface of their respective slottedmembers 35, thedie sectors 28 move progressively toward one another until theirinclined faces 89 come in contact with one another. At the same time, the uppercylindrical surfaces 46a of the pawls which are thrust outwardly by the toggle effect due to the telescopic links 4852 engage under thecircular bearing surface 59 of theabutment member 60; the uppercylindrical surfaces 46a are thus forcibly held in this position by the telescopic links. The curvature center A of thecircular bearing surface 59 and center of rotation B of thepawl 46 are offset in such a manner that the wedging effect caused by the telescopic links 4852 strenuously prestressed thedie sectors 28. The prestressed force is limited by the abutment of the slidingsleeve 55 against the yokes 42 on theblocks 32 by means of the threadedadjustment ring 61 the uppermost position of which is determined by theliner 62.

From the preceding movement it is seen that before the prestress strains thedie sectors 28, they must come into contact with each other before the end of theupper punch 29 reaches the top of thebillet 97 and the prestress, resulting from the engagement of the uppercylindrical surfaces 46a of thepawls 46 under theabutment members 60, is effective when thepunch 29 starts to compress thebillet 97 closed in the axial chamber formed at the center of thedie sectors 28.

It should be noted here that instead of placing the billet on thelower punch 30, which may be magnetized for this reason before the locking operation of the die, it is possible to wait for the die sectors to be almost in contact with one another, thepiston 26 with thepunch 29 not being so low as to interfere with the introduction of the billet. The press must, of course, be temporarily stopped at this moment, in the desired loading position.

As the press piston continues its down stroke and the slidingsleve 55 held against vertical displacement by abutting against the threadedadjustment ring 61 on the yokes 42, thespring 69 starts being compressed. The adjustment offered by the threadedadjustment ring 61 and theshim 62 is such that, taking into account the thickness of thespacers 78 with which thesprings 77 on the movablelower plate member 37 come into contact, the compression of thespring 69 and thesprings 77 begins at the same time. From this fact, as previously mentioned, the spring force or flexibility of the group of springs is equal to that of thespring 69; when theupper punch 23 moves cbwnwards at the speed of thepiston 26, the assembly comprising the three diesectors 28, theblocks 32, the slottedmembers 35 and thelate members 37 and 38 for holding the slotted members, moves downwards at one-half of said speed and thelower punch 30 carried by thecolumn 75 remains stationary with respect to the press table 27. Accordingly, eachpunch 29 and 30 undergoes a displacement relative to the die equal to one half the working stroke of compression of the billet. Under the action of this compression, thelower extension 95 of theupper punch 29 penetrates into the billet. At the same time, the metal of the billet tends to fill entirely thechamber 90 at the center of the three diesectors 28 and to flow through thethroat portions 92 formed at the entrance to theborings 91 formed in the die sectors.

The overall stroke of the punches and the die sectors is limited by thespacer washer 68, acting as an abutment and carried by theflange 64 topping the end of thepiston column 56 on the three diesectors 28 which in turn rest on the ring 83, fixed to thering 81 fixed to the top of thecolumn 75 on the press-table 27; in other words the various parts of the setup are in the position shown at the right-hand side in FIG. 1 1. In this position, the extrusion lengths of the three arms of the intermediate tripod workpiece are adjusted by contact with the end of the screw 44. It is also conceivable to form the end of the screw 44 so as to prepare, at the ends of the arms of the tripod, for subsequent forming or machining, or even, in the case of other kinds of parts, extruded extensions which could be obtained by providing borings, at the end of a member such as the bolt 31, with an extrusion span comparable to the span orthroat 92 provided at the entrance to theborings 91, or even such a throat in an extension of said boring 91; all other end forming operations could be carried out in an analogous manner.

Once the step of forming the intermediate workpiece is completed, the press is returned to its initial position. During its return or up-stroke, the press-piston moves the slidingsleeve 55 upwards into abutment against the upper face of the flange 64 (see the left-hand side of FIG. 11). The slidingsleeve 55 drives the telescopic links 48-52 causing the unlocking of thepawls 46 which return to their vertical position moving theblocks 32 upwards. Theblocks 32 move upwards along the guide-slots 34 in themembers 35, causing thedie sectors 28 to move away from one another. In this way, the cylindrical surfaces of the arms of the tripod receive, at the same time they withdrawn from theborings 91, a finishing sizing or calibration during the return pass through thethroats 90; this finishing step may allow grinding after heat treatment to be dispensed with.

It is noted that the adjustingring 58 for adjusting the length of each of the telescopic links 48-52, enables, in adjusting the lengths of said links, to provide the simultaneity of the raising of the three die sectors during the return or up stroke of the press. The accuracy of the relative position of the three diesectors 28 during this return stroke, in which the surface finishing of the arms of the tripods is effected, is of primary importance.

In addition, it is noted that the angular guiding and wedging of theblocks 32 about the vertical central axis of the setup as well as the operative pushing surface are displaced toward the periphery of the device along the slottedmembers 35, which are held radially by the twoplate members 37 and 38, by bearing on the cylindrical surfaces of the internal recesses of the plate members.

During the combined compression-drawingextrusion operation, the three diesectors 28 are strenuously squeezed against one another by a radial centripetal force F of the order of -200 metric tons. Consequently, the die sectors act as a one-piece die during the extrusion operation per se. Indeed, the inclined bearing faces 89 create, owing to the angles they make with the radial forces F, radial centripetal components which put the entire active central zone of the extrusion die under compression and thereby replace hooping commonly used for extrusion.

The strictness and the accuracy of the verticality and radiality of theextrusion sectors 21 are obtained easily owing to the descending position controlled by the central members: thering 61 and thespacer 68. The principle of moving along guide-slots toward the exterior of the assembly frees the central area of the setup, thereby leaving the necessary and sufficient space for adequately dimensioning the working parts and ensuring their having suitable fatigue strength. The sliding surfaces between theblocks 32 and the slottedmembers 35 thus may be very amply dimensioned as required.

This arrangement and the construction principle used to ensure the perfectly synchronous advance of the application of radial forces and strictly determined positions, also permits numerous variations in use, for example, by modifying the number of guide-slots or slotted members and blocks, which could be standardized to be easily exchanged, between theplate members 37 and 38.

The device which has just been described enables the following press steps to be obtained without any interruption:

a. feeding (the die sectors being open) b. closing the die sectors wedged against one another;

c. drawing or extrusion operation with controlled feed distribution;

d. sizing of finishing and ejection of the workpiece.

The device is robust and simple in view of the forces it may develop and the accuracy of the displacements during operation, The assembly of the device, its adjustments and the replacement of its parts are all easy.

The second or finishing pass is effected by means of a tool set-up shown in FIGS. 15-22. The reason for the finishing pass is the machining of the intermediate workpiece shown in FIG. 10 in order to obtain the finished tripod shown in FIGS. 6 and 7 by simultaneously effecting:

a. longitudinal dimensioning of the threearms 12;

b. forming and sizing thebores 13 at the ends of the arms with the rounded edges or rounds 18, 20 and 21;

c. forming thespherical dome 16 on thecentral body 11 with a surface finish equivalent to a finely ground surface;

d. sizing thecentral bore 14;

e. formingcenters 19 in thecentral body 11 with a view to supporting the tripod during possible later grinding after cementation heat treatment.

The tool set-up for carrying out the finishing pass is, as in the case of the tool set-up for obtaining the intermediary workpiece, mounted on a press, the fram of which comprising theuprights 100, anupper cross member 101 carrying the piston-and-cylinder unit orjack 102 for operating thepiston 103 and a table 104, are shown. The tool setup per se (FIG. 18) comprises two half-dies 105 and 106, avertical punch 107, a first group of three horizontal punches 108 and a second group of three horizontal punches 109. Theupper halfdie 105 is carried by thepiston 103, and thelower halfdie 106 is carried by the slidablevertical shaft 110. The lower half-die 106 is shown in further detail in FIGS. 19 and 20; in elevation, thelower halfdie 106 comprises a frusto-conical portion 1 11 joined at its narrowed end to acylindrical portion 112. The generally flatupper surface 113 has a first array of semi-cylindrical channels designated by thereference numeral 114 and angularly spaced 120 from one another which form with identical channels 114a in thelower surface 113a in the upper half-die 105 cavities having a diameter equal to that of the threearms 12 of the trippod to be formed and adapted to receive thepunches 107. The upper half-die 105 has, in elevation, a shape similar to the lower half-die 106 and comprises a frusto-conical portion 114 joined at its narrow end to acylindrical portion 116. Threeother channels 117 are disposed in the upper surface of the lower half-die 106; these other channels are identical to other channels 117a in the surface of the lower die half facing theupper die half 105. These other channels are the continuation of the first array ofchannels 114 and are adapted to receive the punches 108. Theother channels 117 and 117a have portions 1 18 oflesser diameter at their inner ends,

the function of which will be described hereinafter. Thechannels 113 and 116 open at their inner ends into acentral cavity 119 of spherical dome-shape corresponding to thespherical dome 16 of thebody 11 of the tripod to be formed.

The upper half-die 105 comprises an axial boring or well 120 which has a smaller diameter portion 121 opening on to thesurface 113a and a truncatedconical portion 122 at its opposite end.

Thevertical punch 107 which is housed in the well 120-122 of the upper half-die 105 has a shape corresponding to said well: a smallerdiameter forming end 123 which sizes thecentral bore 14 in the tripod and is axially slidable in the straight portion 121 of the well and expands beyond the upper half-die 105, as will be described hereinafter, and theopposite end 124 of truncated conical shape connected to thecylindrical foot 125.

The horizontal punches 108 have at their metal forming ends an axial projection 126 corresponding to the forming and the sizing of thebores 13 at the ends of the arms of the tripods. At the other ends of each of the punches 108 there are tapered conical sections 127 connected to acylindrical foot 128. The horizontal punches 109 have at their forming ends aprojection 129, of a diameter equal to that of theportions 118 of lesser diameter in thechannels 117, with a pointed tip 130 for forming thecenters 12 in the body of the tripods. At the opposite end of the punches 109, there is a tapered conical section 131 connected to acylindrical base 132.

The mounting of the half-dies and the punches in their respective supports is described hereinafter.

Thevertical punch 107 is secured axially at the free end of thepress piston 103 by means of the threadedring 133. Asleeve 134 is screwed on the upper end of saidpiston 103 and comprises alower flange 135 on which thering 136 rests which also has aflange 137.

A slidingsleeve 138 is slidably mounted on theflange 137 and has at its upper end an inwardly extending flange 139 which freely rests, owing to the force of gravity on theflange 137, on the ring 1.36. The slidingsleeve 138 is screwed on acircular plate member 140 having acentral opening 141 which, too, is circular and receives the rearcylindrical portion 116 of the upper half-die 105. The end of thecylindrical portion 116 is threaded and threadedly engages thelock ring 142. ABelleville washer 143 is interposed between thelock ring 142 and the bottom of the recess in the top surface of theplate member 140 against which it bears. TheBelleville washer 143 in cooperation with thelock ring 142 urges the upper half-die 105 against anannular member 144 which bears against the bottom of a central recess formed in the undersurface of theplate member 140.

Theannular member 144 has a frusto-conicalinner surface 145 corresponding exactly to the conical surface 115 of the upper half-die 105.

Anannular seating spacer 146 rests on the upper surface of theplate member 140 and is slidably mounted relative to thepress piston 103. Acompression spring 147 is received about thepiston 103 in a space defined between thepiston 103 and thesleeve 134 and interposed between the bottom of the sleeve and theannular seating spacer 146. Vertical guiding spacers 148 spaced about the periphery of the base of thesleeve 134 are received in notches in the sides of theplate member 140 for ensuring the centering of theplate member 140 with respect to the press piston and the tool setup.

The lower half-die 106, as mentioned above, is carried by a vertical slidingshaft 110 which has at its upper end alarger diameter portion 110a against which the lower half-die 106 is clamped by means of a threadedrod 150, which passes axially along the entire length of theshaft 110, in cooperation with anannular member 151 identical toannular member 144 against which the upper half-die 105 bears. Theshaft 110 is slidably mounted in thesleeve 152 which in turn is slidable in aring 153 threadedly engaging a tapped hole inplate member 154. Asmooth ring 155 also rests on thesleeve 152 and acts as a spacer member, as will be discussed below.

Theplate membcr 154 is secured to the table 104 of the press; aflat ring 156 carrying a downward extendingskirt 157 is secured on the press-table 104.

The lower end of theshaft 110 rests on a cylindrical spindle which is extended downwardly by asleeve 166 which tops the upper end of avertical shaft 167 which is fixed to thesleeve 166 by apin 168. Thesleeve 166 forms, relative to thespindle 165, ashoulder 169 on which rests the inwardly extendingflange 170 of asleeve 171 having a flange 172 at its lower end. The

lower end of acompression spring 173 bears against the outwardly extending flange 172. The upper end of 'the compression spring is urged against the underside of theannular member 174 which is guided in theskirt 157 and is in abutment against the underside of thering 153. Thesleeve 152 which slides on theshaft 110 also rests on theannular member 174. Thesleeve 166 is slidably mounted on acylindrical bush 175 mounted in aplate 176 which is welded on the upper ends ofa pair ofbrackets 177, one at each side of the section line in FIG. 17, which are maintained parallel bytransverse tie rods 178 passing throughuprights 100 of the press and fixed by nuts 179.Tubular bracing members 180, 181 are received on the tie rods for maintaining thebrackets 177 in their desired positions. Aplate 182, similar to theplate 176, is welded to the underside of thebrackets 177; acylindrical bush 183 in which theshaft 167 slides, is mounted in theplate 182.

A mounting collar or rockinglever 184 is fixed to theshaft 167 underneath thesleeve 166 and has a yoke to each side of theshaft 167, including one yoke in which afirst link 187 pivots on a pin-186. Asecond link 189 is pivotally mounted on aspindle 190 extending between twolateral plates 191 which are each fixed along one of their vertical sides to asleeve 192 on atie rod 193 and retained thereon by anut 202. Each pair oflinks 187 and 189 forms a yoke for mounting aroller 194 for rotation about theircommon pivot pin 188 and rolling displacement along a part-circular cam member 195 which is held between the corresponding pair ofbrackets 177 by a threadedrod 196 withshims 197 and 198 between thebrackets 177 and thecam member 195. The radius of curvature of the cam surface and the mounting of the cam member are such that the center of curvature is substantially along the axis of thepivot pin 186 when the press is in its raised or open position shown in FIG. 15.

The fourtie rods 193 each having atubular bracing member 199 received thereon connect the lower bridge formed by thelateral plates 191 withtransverse spindles 190 to the upper bridge comprising two similarlateral plates 200 which are each fixed along one of their vertical sides to asleeve 201 received and clamped on the tie rods against thetubular bracing members 199 bynuts 202, thelateral plates 200 being connected to each other bysections 203. The upper bridge thus made up is carried by anannular member 204 retained toward the top of thesleeve 135 on thepress piston 103, with the cooperation of rings andcirclips 205 on aring member 206 having a lower toroidal surface which cooperates with the upper surface of corresponding shape on aring member 207 for forming a ball-and-socket joint, thering member 207 carried on anannular member 208 being freely slidably mounted on thesleeve 135 and supported on thering 136.

The horizontal punches 108 and 109 are mounted in the same way, each being secured by means of ascrew 209 on avertical ram 210, formed as a rectangular plate (see FIGS. 18 and 21) mounted in a guide-slot 211 in an oblique ram or block 212, which is of the same type as theblocks 32 in FIG. 11, to the extent that eachoblique ram 212 is T-shaped in cross-section providing two lateral ribs 213 (FIGS. 21 and 22) making an angle a 12 with theslot 211. The body of eachram 212 and itsribs 213 are received in the T-shaped slot of amember 214, which is identical to the slottedmembers 35 in the tool set-up of FIG. 1 1, the front face of which has the same slope 0: relative to the vertical as the lateral ribs of thecorresponding ram 212. The six slottedmembers 211 correspond to the six rams (three for the punches 108 and three for the punches 109), are hooped by acylindrical member 215 and held, as is thecylindrical member 215, between thelower plate member 154, as previously mentioned, and anupper plate member 216, the two plate members being urged toward each other by thetie rods 217 and associated bracing-members or cross-members similar to those in FIGS. 11 and 12 being provided, if necessary, for maintaining the desired angular spacing between the slottedmember 214 each of which may, however, have a 60 opening relative to a point located on the vertical axis of the press in case the spacers are not required.

The slottedmember 211 for eachoblique ram 212 is open along its forward face for forming acorridor 217 for the passage of the base orfoot 128 or 132 of the punch mounted on thevertical ram 210 with which it cooperates. Each ram or block 212 also has at its base two projectingportions 220 adapted to come to rest at the end of the press stroke on thesmooth ring 155 mounted on thevertical shaft 110.

The device which has just been described operates as follows:

When the press is opened, i.e.,-in the raised position shown in FIG. 15, an intermediate tripod workpiece, obtained as described hereinabove and shown in FIG. 10, is placed in the lower half-die 106. In this position, therams 212 are at their uppermost position and the horizontal punches 108 and 109 are simply in engagement with the closed ends of theirrespective channels 114 and 117 in the lower half-die 106, leaving a space free for introducing the workpiece.

Thepress piston 103 is then lowered which in turn brings the bottom of the upper half-die in contact with the lower half-die 106. The combination forming the so-called upper bridge 200-203 which is suspended from the sleeve fixed to thepiston 103, thetie rods 193 and the so-called lower bridge 191-192 also moves downwards with thepiston 103 which causes thetransverse spindles 190 and thelinks 189 to be pulled downwards. The linkage formed by thelinks 189 and 187 progressively opens; however, as long as therollers 194 rests against the part-circular cam surface of themembers 195, the pivot pins 186 and therefore the mountingcollar 184 and thevertical shaft 167 with which it moves and the spindle fixed by thesleeve 166 ontheshaft 167, remain stationary. This phase of the operation continues until therollers 194 reach the vertical portion on the cam surfaces which corresponds to the moment when the two half-dies 105 and 106 come into contact with each other. At this moment, thelinks 187 and 189 are practically in alignment and the lower bridge pulls downwardly by means of the links, the mountingcollar 184, theshaft 167 and thespindle 165 which, when it retracts, leaves the slidingshaft 110 free to descend with the closed half-dies. The half-dies bring with them the punches 108 and 109 while the vertical rams which support the punches 108 and 109 move downwardly in the guide-slots 211 of the oblique rams 212', this movement continues until theenlarged head 110a of thevertical shaft 110 comes into abutment againstsmooth ring 155. From this moment on, and for the reason that thelinks 187 and 189 are fully opened and in vertical alignment with each other, a closed rigid loop is formed, comprising the two half-dies 105 and 106, the slidingshaft 110, thespindle 165, theshaft 167, thelinks 187 and 189, thelower bridge 191, thetie rods 193, the upper bridge 200-203, the annular andring members 204, 206, 207 208, thering 136, thesleeve 133 and thepress piston 103. This closed rigid loop ensures, independently of the operation of the press, the squeezing of the two half-dies against each other without the force initially exerted by the piston which may reach 100200 metric tons. The half-dies are thus held closed without subsequently reducing the actual capacity of the press which therefore can be used in its totality for forming.

Thus, thepiston 103 continues its downward movement; thecircular plate member 140 abuts against the upper face of the oblique rams 212 which begins their downward movement along the slottedmembers 214 moving toward the vertical axis of the press and bringing with them the punches 108 and 109. It should be noted that at this moment thevertical rams 210 carrying their punches have reached the end of their travel with respect to the oblique rams, and since the two half-dies between which the punches are held move downwards with thepiston 103 owing to the presence of the closed rigid loop described above, there is no further relative movement betweeen therams 210 and 212. Therams 212 resting against thering 155 also drive downwardly therewith thesleeve 152 and theannular member 174 which compresses thespring 173.

Thespring 147 is also gradually compressed, and thepunch 107 moves downwards toward the upper half-die 105. Under the force exerted by thepiston 103, thepunch 107 enters thecentral bore 14 of the tripod workpiece which is between the two dies for finishing of thebore 14 and extruding or driving back the metal for forming, in thespherical cavity 119 of the lower half-die 106, thespherical dome 16 of thetripod body 11. Simultaneously, since theannular plate member 140 is in contact with thesleeve 134, thepiston 103 then ensures by itself the rest of the downward movement of therams 212 through theelements 140 and 134, and therefore the penetration of the horizontal punches 108 and 109 into their associated openings in the half-dies. The punches 108 size thearms 12 of the tripod to their exact desired length and form thebores 13 in the ends of the arms of the tripod arms, and the punches 109 formed thecenters 19. The position of the tool setup at the end of the stroke is clearly shown in FIG. 18.

The press piston is then raised and the other members, parts and elements of the device return to their positions as shown in FIG. 15, thespring 173 effecting the return movement of therams 212 and therefore their moving apart from one another and the moving apart of the punches 108, 109. The finished tripod can then be removed.

It should be noted that the closed rigid force loop binding system of the force on the press in combination with the system of toggle joints controlled by cams gives a cooperation of difference sequences with very great precision and accuracy of movements, this permitting mass production under particularly economical and rapid conditions.

The value of the force for closing the half-dies is easily adjusted by thenuts 202 and the length of the bracingmembers 199.

The shape of the cam surfaces shown in the drawings could conceivably be varied in their radial or vertical dimensions as a function of the part to be formed.

It is also possible to replace the function of thecam 195 and theroller 194 with a jack adapted to exert a force at the common pin of the toggle joint and controlled electrically at the precise moment while prev serving the advantage of the half-dies closure sequence in the down stroke of the press and the advantage of the closed force looping for closing the die which does not reduce the force available for effecting the forming work per se.

The force looping system may also be effected in such a way that the force exerted along the axis of the press on the tripod to be finished, by means of the laterally operating punches, is at every moment proportional to the force of penetration of the punches into the workpiece.

Such an embodiment is described hereinafter with reference to FIGS. 23 and 24 which, for the sake of simplification, only show the basic elements of the tool setup.

The machining which is to be carried out in the illus trated embodiment is the cutting of thelongitudinal grooves 225 in the surface of a slidinghub 226. Thelongitudinal grooves 225 are part-cylindrical (FIG. 24) in cross-section and have part-spherical end portions (FIG. 25). Thelongitudinal grooves 225 are intended to receive ball bearings for reducing friction during rotation as well as axial displacement of thehub 226 in a journal. The hub comprises twoshoulders 227 and 228 one to each side of the central portion in which the twelvelongitudinal grooves 225, which are grouped in six pairs of aligned grooves, are to be formed.

The tool setup essentially comprises sixpunches 229 each having a pair ofteeth 230 corresponding to a pair of alignedgrooves 225. Thepunches 229 are held inoblique rams 231, similar to therams 212 in FIG. 15, and slidable in slottedmembers 232, similar to the slottedmembers 214 in FIG. 15, which are clamped together by an annular hooping member (not shown).

Adrive member 233 is mounted on the press piston (not shown) and comes into contact against theshoulder 227 of the hub to be formed. The hub in turn transmits the force through itslower shoulder 228 to alower drive member 234 which bears against an annular member to which it is fastened byscrews 236. Theannular member 235 is connected bytie bolts 237 to anupper plate member 238 which in turn bears against the top of the rams 231 (at the left-hand side of FIG. 23 apunch 229 is shown very schematically). When the press piston is actuated, the hub being previously positioned on thelower drive member 234 and thedrive member 233 formed in two parts on being engaged the upper part, the descent of thedrive member 233 brings about through the workpiece itself, thelower column 235,tie bolts 237 and theupper column 238, the descent of therams 231 and therefore the penetration of theteeth 230 of thepunches 229 into the hub to be machined. Axial creep of the metal of the hub is avoided during the operation of the punches since the hub is compressed vertically by a force proportional to the radial force of penetration of the six punches. If the axial retaining force applied against the workpiece were not proportional to the radial forming forces, the grooves thus formed would be axially deformed by an undesirable lengthening of extrusion and their profiles would be altered making the resulting part unsuitable for the intended use. Indeed, this workpiece cannot be ground after cold forming or heat treatment and the forming according to the invention must therefore provide the precision necessary for correct rolling and sliding of ball bearings without subsequent modification.

Further, the inevitable variations in the hardness of the starting metal does not modify the quality of the grooves formed.

A second advantage of the rigid closed looping system is to produce an axial force in the range of 100 metric tons or more in a simple manner by avoiding spring systems which take up a great amount of space and are prohibitive in cost, without increasing the force necessary for the operation of the press. In other words, if a 120 MT press is employed for example, it is possible to exert a clamping force of 150 MT while preserving the total capacity of the press, i.e. 120 MT for the radial forming of the workpiece.

In case the surfaces bearing against theshoulders 227 and 228 are inadequate for exerting an efficient axial force, other bearing surfaces could be provided at the ends of the hub which would enable the advantageous provision without cost of center points shown in dashdotted lines in FIG. 22 and useful in assembling the hub in a transmission tube.

FIGS. 24 and 25 show another variety of parts of the tripod family which may be obtained with the device according to the invention. In this part, the portions extending radially of and perpendicular to the main axis are received in a shaft of variable length, the machining of the part is carried out by means of a device similar to that of FIGS. 11 and 12.

The starting piece is also a cylindrical billet, but longer than the one employed for the tripod of FIGS. 6 and 7. This type of part may be necessary when the tripod is to be connected to a tube for example, by a groove system. The radial projection may also be located at the end of the bar.

FIGS. 27 and 28 show another variety of tripod in which a cylindrical central bore goes straight through the part. The starting billet is tubular in this case and is shown in FIG. 29. During the machining operation effected on a setup identical to that of FIGS. 11 and 12, a filler-block or antifriction lining is inserted inside the tubular billet preventing local internal buckling. This lining is removed while the punches are fed into the cylindrical recesses provided therefor.

This antifriction lining may advantageously be replaced by a ring of incompressible elastromeric material which fills all or part of the cavity in the billet and accompanies the deformation of the extruded billet while aiding this deformation, owing to the high hydrostatic pressure exerted on this ring during the deformation of the billet. This is intended to prevent local internal buckling of the billet and favor extrustion in the ONS radial directions.

The central bore in the tripod which is shown as passing straight through the tripod may also be a blind bore with the provision of an incompressible lining appears to be indispensible for a proper extrustion resulting in a sound part.

It is realized that the central bore and, if need be, the starts of radial cavities or bores obtained by extrusion must naturally be compatible with the use of such a part or with the subsequent shaping operations when they are necessary. After extrusion, the lining may be removed, or left in place and considered waste material.

The lining could be formed of various deformable incompressible materials or even a suitable liquid.

FIG. 30 shows a cross-piece for a universal joint which may be obtained according to the invention, comprising four radially projecting portions extending perpendicular to the main axis which is known as a cross-piece when used in universal joints. The starting billet in this case is similar to that shown in FIG. 9.

This type of cross-piece is always obtained on the setup shown in FIGS. 11 and 12 for the intermediary workpiece. The finishing of the cross piece may be carried out on a setup such as shown in FIGS. 15-20 using the identical principles.

The above embodiments and examples are given by way of example. It is recognized that numerous other parts having a main axis and plurality of projecting portions distributed radially thereabout may be treated according to the method and by the means of the present invention.

What is claimed is:

1. A setup for a press including a piston and a table for cold-forming metal parts of the type having a central body and generally radially projecting portions extending outwardly from the central body starting with substantially cylindrical metal billets, said setup comprising a first assembly including a multi-part die together defining a cavity of of a shape corresponding to the shape of the part to be formed, said cavity including a central chamber cavity and radially projecting cavities adapted to receive corresponding portions of the part being formed, said die having openings therein for receiving punches, and a second assembly including punches adapted to penetrate into said die through the openings, the parts of the die of said first assembly and the punches of the second assembly defining metal forming parts of the setup, the metal forming parts of one of the assemblies being carried by the piston and table of the press, the metal forming parts of the other assembly being carried by rams for axial and radial movement therewith, said rams being slidably mounted for displacement parallel to the axis of the piston along oblique slotted members spaced about said axis and clamped between upper and lower plate members urged toward one another, said rams being arranged to be driven along at least part of the working stroke of said piston in their slotted members to come together.

2. A setup according to claim 1, wherein the die parts are carried by the piston and the table, respectively, and the punches are carried by the rams, the arrangement of the die parts being such that the rams come together after the die parts are brought together to close the die.

3. A setup according to claim 1, wherein the die parts are carried by the rams and the punches are carried by the piston and the table, respectively, the arrangement of the die parts being such the rams come together before the die parts are brought together to close the die.

4. A setup according toclaim 3, wherein the number of die parts is equal to the number of projecting portions on the piece to be formed, the radial cavity in each die part being in the form of a transverse boring extending generally radially relative to said axis through the die part and terminating at its radially inner end in a narrowed throat opening into the central chamber, said central chamber being defined by partcylindrical segments on each die part, said central chamber being coaxial with said axis, open at its ends and adapted to receive the cylindrical starting billet, the cross-section of said central chamber along said axis in the immediate vicinity of the borings being at least in part that of the central body of the piece to be formed.

5. A setup according to claim 4, wherein the punches carried by the table and the piston, respectively, are coaxial with said axis and adapted for compressing the starting billet.

6. A setup according toclaim 5, wherein each ram carrying a die part has connected thereto linkage means including a pair of levers having a common pivoted connected, one of the levers also being pivotally connected to said ram and the other lever being pivotally connected to a sliding sleeve slidably mounted on the piston, compression spring means urging the sliding sleeve toward the rams, the sliding sleeve bearing against the rams for displacing the rams along their slotted member during the forming stroke of the press.

7. A setup according to claim 6, further comprising means for preventing the common pivoted connection of the levers of each linkage means for moving from a position in which the sliding sleeve is most remote from the rams but allowing the common pivoted connection to move from said last-mentioned position once the die parts have been brought into contact with one another, and a retaining abutment cooperating with the linkage when the die parts are in contact with one another for clamping the die parts.

8. A setup according toclaim 2, for use in finishing intermediate workpieces, wherein the die parts are upper and lower die halves, one of the die halves being carried on the piston and the other of the die halves being carried on the table, wherein the die halves have arrays of radial channels in their opposed faces combinable to define said radially projecting cavities and adapted to receive an intermediate workpiece.

9. A setup according toclaim 8, wherein the punches carried on the rams are adapted to penetrate into the radial channels in the die halves through the openings therein, the rams being slidable parallel to said axis along other rams movable oblique to said axis.

10. A setup according toclaim 9, further comprising movable means for mounting the upper die half on the piston and compression spring means for urging the upper die half toward the lower half die.

1 l. A setup according toclaim 10, wherein said lower die half is carried by a shaft slidable in said press table further including means enabling the sliding movement of the shaft in the press table in response to the displacement of the press piston to a position in which the shaft is secured against movement by horizontal cross bars secured by vertical tie rods to a member adapted to abut against an element fixed to the pis' ton.

l2. Setup according toclaim 3, wherein each die part bearing ram is connected to the press piston through a toggle provided with two levers articulated one relative to the other, the first of said levers further articulated on the ram and the second lever on a sleeve slidingly mounted on the press piston with interposition of a compression spring which urges said sleeve towards the rams, said sleeve being so disposed to apply a pressure onto said rams and to displace said rams when the press piston is moved downwardly, and means for preventing the articulation common to said two levers to appreciably move aside from its position wherein the distance between sliding sleeve and rams is at its maximum, and to subsequently adapt said articulation to move apart and to thus engage under a holding stop when the die parts have been brought into contact to each other to lock said die parts in said contacting positions.

Claims (12)

1. A setup for a press including a piston and a table for coldforming metal parts of the type having a central body and generally radially projecting portions extending outwardly from the central body starting with substantially cylindrical metal billets, said setup comprising a first assembly including a multi-part die together defining a cavity of of a shape corresponding to the shape of the part to be formed, said cavity including a central chamber cavity and radially projecting cavities adapted to receive corresponding portions of the part being formed, said die having openings therein for receiving punches, and a second assembly including punches adapted to penetrate into said die through the openings, the parts of the die of said first assembly and the punches of the second assembly defining metal forming parts of the setup, the metal forming parts of one of the assemblies being carried by the piston and table of the press, the metal forming parts of the other assembly being carried by rams for axial and radial movement therewith, said rams being slidably mounted for displacement parallel to the axis of the piston along oblique slotted members spaced about said axis and clamped between upper and lower plate members urged toward one another, said rams being arranged to be driven along at least part of the working stroke of said piston in their slotted members to come together.

2. A setup according to claim 1, wherein the die parts are carried by the piston and the table, respectively, and the punches are carried by the rams, the arrangement of the die parts being such that the rams come together after the die parts are brought together to close the die.

3. A setup according to claim 1, wherein the die parts are carried by the rams and the punches are carried by the piston and the table, respectively, the arrangement of the die parts being such the rams come together before the die parts are brought together to close the die.

4. A setup according to claim 3, wherein the number of die parts is equal to the number of projecting portions on the piece to be formed, the radial cavity in each die part being in the form of a transverse boring extending generally radially relative to said axis through the die part and terminating at its radially inner end in a narrowed throat opening into the central chamber, said central chamber being defined by part-cylindrical segments on each die part, said central chamber being coaxial with said axis, open at its ends and adapted to receive the cylindrical starting billet, the cross-section of said central chamber along said axis in the immediate vicinity of the borings being at least in part that of the central body of the piece to be formed.

5. A setup according to claim 4, wherein the punches carried by the table and the piston, respectively, are coaxial with said axis and adapted for compressing the startinG billet.

6. A setup according to claim 5, wherein each ram carrying a die part has connected thereto linkage means including a pair of levers having a common pivoted connected, one of the levers also being pivotally connected to said ram and the other lever being pivotally connected to a sliding sleeve slidably mounted on the piston, compression spring means urging the sliding sleeve toward the rams, the sliding sleeve bearing against the rams for displacing the rams along their slotted member during the forming stroke of the press.

7. A setup according to claim 6, further comprising means for preventing the common pivoted connection of the levers of each linkage means for moving from a position in which the sliding sleeve is most remote from the rams but allowing the common pivoted connection to move from said last-mentioned position once the die parts have been brought into contact with one another, and a retaining abutment cooperating with the linkage when the die parts are in contact with one another for clamping the die parts.

8. A setup according to claim 2, for use in finishing intermediate workpieces, wherein the die parts are upper and lower die halves, one of the die halves being carried on the piston and the other of the die halves being carried on the table, wherein the die halves have arrays of radial channels in their opposed faces combinable to define said radially projecting cavities and adapted to receive an intermediate workpiece.

9. A setup according to claim 8, wherein the punches carried on the rams are adapted to penetrate into the radial channels in the die halves through the openings therein, the rams being slidable parallel to said axis along other rams movable oblique to said axis.

10. A setup according to claim 9, further comprising movable means for mounting the upper die half on the piston and compression spring means for urging the upper die half toward the lower half die.

11. A setup according to claim 10, wherein said lower die half is carried by a shaft slidable in said press table further including means enabling the sliding movement of the shaft in the press table in response to the displacement of the press piston to a position in which the shaft is secured against movement by horizontal cross bars secured by vertical tie rods to a member adapted to abut against an element fixed to the piston.

12. Setup according to claim 3, wherein each die part bearing ram is connected to the press piston through a toggle provided with two levers articulated one relative to the other, the first of said levers further articulated on the ram and the second lever on a sleeve slidingly mounted on the press piston with interposition of a compression spring which urges said sleeve towards the rams, said sleeve being so disposed to apply a pressure onto said rams and to displace said rams when the press piston is moved downwardly, and means for preventing the articulation common to said two levers to appreciably move aside from its position wherein the distance between sliding sleeve and rams is at its maximum, and to subsequently adapt said articulation to move apart and to thus engage under a holding stop when the die parts have been brought into contact to each other to lock said die parts in said contacting positions.

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