Means For Making Pulleys

Abstract

A pulley making method and apparatus for forming a pulley having a pulley groove of given cross section defined by flange walls connected through the root of the groove, the groove having a given root diameter, from a pulley blank in the form of a sheet metal cup having an annular bulge in the cup wall and an adjacent flaring wall portion, with a valley defined between the bulge and adjacent flaring wall portion. A pulley is formed from the blank by engaging the flaring wall portion and the side of the bulge remote from the valley with axially movable dies and moving the dies together to crush the bulge and form it into a double wall. Groove-forming rolls are positioned within the valley so that they extend radially inwardly to an imaginary circle having a diameter equal to the root diameter prior to the attainment of a final forming position by the axially movable dies. Relative rotation is established between the pulley blank and the group of rolls and the rolls roll within the valley to receive the axial thrust of the bulge as its crushing is completed, and to keep the valley clear as its shape approaches and conforms to the desired pulley groove cross section.

Parent Case Text

This application is a continuation of Ser. No. 687,695 filed Dec. 4, 1967, now abandoned.

Description

BACKGROUND OF THE INVENTION

Single or multiple V-groove pulleys have been and are conventionally formed from stamped sheet metal by first performing a cupping operation, providing an outwardly flared end portion on the cup and then providing at least one circumferential fold of the cup which defines a pulley groove with the outwardly flared end portion of the cup or a second pulley groove with an adjacent circumferentially folded portion of the cup.

In order to form such circumferentially folded cup wall portions, techniques have been proposed which involve axially restraining a sheet metal cup having a cylindrical side wall between a headstock spindle and a tailstock spindle. A mandrel assembly which comprises a multiplicity of radially extending fingers is positioned within the cup between the headstock spindle and the tailstock spindle. The cylindrical side wall of the cup is then deformed radially inwardly by engaging the cylindrical side wall with rollers to form valleys in the side wall between the open end of the cup and the mandrel assembly and between the mandrel assembly and the closed end of the cup. During this rolling operation, the headstock and tailstock spindles are rotated and moved together to form the desired V-grooves in the pulley as the forming rolls are moved radially inwardly.

According to such prior art techniques, the headstock and tailstock spindles are moved together to their final forming positions prior to or simultaneous with the attainment of the ultimate radially inward movement of the forming rolls.

Pulleys formed according to this prior art techniques are drastically worked and may be stretched or thinned by such working operations, thereby creating zones or areas of weakness in the pulleys.

Other prior art techniques involve the formation of V-grooves on the side wall of the pulley by press-forming operations wherein a multiplicity of dies are brought together to form the ultimate pulley configuration. The dies are moved against a cup-shaped pulley blank and those dies are moved by mechanical linkages to a predetermined final position. Frequently, however, the metal forming the cup blank varies in wall thickness as a result of the cupping operation or because of variations in thickness of the as-received sheet stock, so that close tolerances in the final product or use of minimum-gage material cannot be accomplished without using costly close-tolerance sheet stock or running into unacceptable die breakage.

In many of these prior art techniques, a pulley hub is brazed onto the formed pulley. Since the brazing operation is conducted at a relatively high brazing temperature, the pulley may be distorted as the working stresses are relieved. After the brazing operation, the pulley must be checked for any distortion and, if necessary, reworked.

Generally, separate final finishing in a rolling operation with finish rolls is necessary in many prior art methods.

The forming process and apparatus according to this invention overcome prior art pulley-forming problems such as those mentioned, simplify the prior art steps in making the pulley, and produce a finished pulley having an accurately located center hub or connecting aperture.

These and other features, advantages, and objects of the invention will become more readily apparent and more fully understood from the following detailed description of the invention and from the accompanying drawings.

In the drawings:

FIG. 1a is a cross-sectional, elevational view of a cup after blanking, drawing, and piercing operations.

FIG. 1b is a cross-sectional, elevational view of a cup according to a further aspect of this invention, showing the cup after blanking and drawing operations.

FIG. 2a is a cross-sectional, elevational view of the cup illustrated in FIG. 1a after further mechanical working operations.

FIG. 2b is a cross-sectional, elevational view of the cup illustrated in FIG. 1b after further mechanical working operations.

FIG. 3a is a cross-sectional, elevational view of the cup illustrated in FIG. 2a showing the cup in the form of a pulley blank after still further mechanical working operations have been performed and showing a hub brazed on the cup.

FIG. 3b is a cross-sectional, elevational view of the cup illustrated in FIG. 2b showing the cup in the form of a pulley blank after still further mechanical working operations have been performed.

FIG. 4a is a cross-sectional, elevational view of the pulley blank illustrated in FIG. 3a being formed in accordance with the method according to this invention.

FIG. 4b is a cross-sectional, elevational view of the pulley blank illustrated in FIG. 3b being formed in accordance with the method of this invention.

FIG. 5a is a cross-sectional, elevational view of a completed pulley formed according to one aspect of the present invention and associated forming dies.

FIG. 5b is a cross-sectional, elevational view of a completed pulley formed in accordance with a further aspect of this invention and associated forming dies.

FIG. 6 is a fragmentary front elevational view partly in section of a pulley forming machine according to this invention.

FIG. 7 is a cross-sectional plan view of the apparatus illustrated in FIG. 6, the plane of the view being indicated by the line 7--7 in FIG. 6.

FIG. 8 is a fragmentary cross-sectional view of the apparatus, the plane of the section being indicated by the line 8--8 in FIG. 7.

FIG. 9 is an enlarged, fragmentary, cross-sectional view, the plane of the section being indicated by the line 9--9 in FIG. 7.

FIG. 10 is a schematic hydraulic circuit diagram of controls for the apparatus.

Referring now to the drawings, and particularly to FIGS. 1a, 2a, 3a, 4a, and 5a, a cup blank 10 is illustrated. In the condition illustrated in FIG. 1a, the cup 10 has been punched from flat sheet stock and drawn into a cup having a radially extending flange 11. The cup is also pierced to provide an axial bore 12. The cup is then formed into the condition illustrated in FIG. 2a by forming a rim 13 on the flange 11 and extruding the bore 12 to provide an annular lip 14 on the top of the cup. As may be seen in FIG. 3a, the cup 10 is then provided with a hub 15 which is brazed within the lip 14. As will become apparent, any distortion caused by the brazing operation is corrected during subsequent forming operations, since the axis of the pulley hub is employed as a working axis.

The side wall is provided with a bulge 16 by, for example, the technique set forth in U.S. Pat. No. 2,929,345. The bulge 16 and the flange 11 define a circumferentially extending valley 17. The form of the cup 10 illustrated in FIG. 3a comprises a pulley blank 20 which is formed into a pulley in accordance with the teachings of this invention.

As may be seen in FIG. 4a and as will be explained in greater detail, the flange 11 of the pulley blank 20 and the side of the bulge 16 remote from the valley 17 are respectively engaged with axially movable members 21 and 22. When the axially movable members 21 and 22 have been moved together to the position illustrated in FIG. 5a, the bulge 16 is crushed and formed into a doubled wall 23. During the axial movement of the members 21 and 22, the pulley blank 20 is rotated about the axis of the pulley hub 15 and a group of at least two groove-forming rolls 24 and 25 are positioned within the valley 17 so that they extend radially inwardly to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove. The rolls 24 and 25 roll within the valley 17 to receive the axial thrust of the bulge 16 as it is formed into the doubled wall 23. The rolls 24 and 25 keep the valley 17 clear as its shape approaches and conforms to the desired pulley groove cross-section which is defined by the cross-section of the rolls 24 and 25.

Referring now to FIGS. 1b, 2b, 3b, 4b, and 5b, a pulley is formed according to a further aspect of this invention. A cup 30 is illustrated in FIG. 1b. The cup 30 is blanked and drawn to provide an outwardly flaring flange 31. The cup 30 is further formed to the condition illustrated in FIG. 2b by providing a downwardly extending rim 33 on the flange 31.

As is shown in FIG. 3b, the cup 30 is then provided with a bulge 36 which defines a valley 37 with the flange 31. The form of the cup illustrated in FIG. 3b comprises a pulley blank 40 which is formed into a pulley in accordance with one aspect of this invention.

As may be seen in FIG. 4b, the flange 31 and the side of the bulge 36 remote from the valley 37 are respectively engaged by axially movable members 41 and 42 respectively. The axially movable members 41 and 42 are moved together to crush the bulge 36 and form it into a doubled wall 43. During the axial movement of the members 41 and 42, the pulley blank 40 is rotated about its axis and a group of at least two groove-forming rolls 44 and 45 are positioned within the valley 37 so that they extend radially inwardly to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove.

The rolls 44 and 45 roll within the valley 37 to receive the axial thrust of the bulge 36 as its crushing is completed. The rolls 44 and 45 keep the valley 37 clear as its shape approaches and conforms to the desired pulley groove cross section. During the final stages of the forming operation on the pulley blank 40, an aperture 46 is punched in the blank 40 by a punch member 47 which is provided in the axially movable member 42. The punch member accurately establishes the location of aperture 46 so that the axis of the aperture corresponds to the axis of the formed pulley.

Referring now to FIG. 6, a forming machine 50 is illustrated. The embodiment of the machine 50 illustrated in FIG. 6 is intended to form a pulley from the pulley blank 20 illustrated in FIG. 3a. It is to be understood, however, that the machine 50 may be adapted to perform such an operation on the pulley blank 40 by providing one of the axially movable members with a center punch to form the aperture 46 in that pulley blank.

The machine 50 includes a frame having a bed assembly 51, side frame members 52 and 53, and a top crosspiece 54 connected to the side frame members 52 and 53.

The bed 51 may include a slide 55 having a depending plate portion 56. The plate portion 56 is connected to a ram 57 of a double-acting hydraulic cylinder 58. The cylinder 58 is fixed at one end to the side frame 52 and drives the slide 55 from the position illustrated in dotted outline in FIG. 6 to the position illustrated in phantom outline in that Figure.

The slide 55 carries a pair of bottom die means 59 on its upper surface. Each die means 59 comprises a die block 60 which is fixed to a driving member 61. The driving member 61 is fixed to a plate 62 which is driven by a drive shaft 63. The drive shaft 63 has a relatively large upper portion 64 connected to the plate 62 and to a bearing plate 65 which is rotatable on bearings 66. The drive shaft 63 further includes a relatively small portion 67 which extends through the slide 55 and is journaled by bearings 68. A motor 69 drives the shaft 63, the bearing plate 65, the plate 62, the driving member 61, and the die block 60 about their cylindrical axes.

Each die block 60 has one degree of freedom with respect to the machine frame. If a machine is provided with a single die block 60 however, a die block 60 may have either one degree of freedom (a single die block 60 mounted on the slide 55), or zero degrees of freedom (a single die block 60 fixed to a non-movable bed 51).

In axial alignment with the die 60 is a die 70. The die 70 is fixed to a cylindrical block 71 which is rotatably mounted in a bearing assembly 72. The bearing assembly 72 is fixed to a plate 73 which is mounted at one end of a first translator means which includes a ram 74 and a double-acting power cylinder 75 which is fixed to the top crosspiece 54. The ram 74 and its associated elements comprise output means for advancing the die 70 so that the die 70 and the die block 60 are translated together toward a final forming position which defines a die cavity corresponding to portions of the ultimate cross section of the article to be formed.

The die 70 and the die block 60 may both move to a final forming position, if desired, by providing a translator means for the die block 60. The invention therefore includes at least one of the dies 60 and 70 having more than zero degrees of freedom with respect to the frame. In the illustrated embodiment, the die 70 has one degree of freedom with respect to the frame (axial), and the die block 60 has one degree of freedom with respect to the frame (lateral). The die 70 has zero degrees of freedom with respect to the output end of the first translator means. Taken together, the die 70 and the die block 60 have less than three degrees of freedom with respect to the frame.

The machine 50 further includes a forming means 76 which comprises a group of at least two groove-forming rolls 24 and 25. The rolls 24 and 25 are rotatably mounted on spindles 79 and 80 which are fixed laterally with respect to each other so that the edge-to-edge distance between the rolls 24 and 25 extend radially inwardly to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove. The spindles 79 and 80 are slidably mounted in lower blocks 81 and 82 and are urged to a normal position illustrated in FIG. 6 by springs 83. The upper ends of each spindle 79 and 80 are slidably received by upper blocks 84 and 85 so that the spindles 79 and 80 and their rolls 24 and 25 are axially floatable with respect to each other and with respect to the bed 51 and so that the rolls 24 and 25 have less than two degrees of freedom with respect to each other.

As may be seen most clearly in FIGS. 7 and 8, the upper and lower blocks 81, 82, 84, and 85 are mounted at the ends of arms 86 and 87. The arms 86 and 87 are adjustably fixed to a crossbar assembly 88. The arms 86 and 87 may be adjusted relative to each other by adjusting screws 89 and 90 respectively so that the desired root diameter may be precisely established and maintained. The crossbar assembly 88 has plates 91 which are fixed to and separated by a spacing cylinder 92.

The cylinder 92 is pivotally connected to a shaft 93 which is fixed to a crossplate 94. The crossplate 94 is fixed at its ends to sleeves 95 and 96, which are slidably mounted on guide rods 97 and 98. The guide rods 97 and 98 are mounted parallel to each other by mounting blocks 99 which are fixed to the bed 51.

A strap 100 extends downwardly from the crossplate 94 and is connected to a second translator means which includes one end of a power ram 101 and an associated double-acting cylinder 102. The cylinder 102 drives the ram 101 and, therefore, the assembly comprising the shaft 93, the cylinder 92, the plates 91, the crossbar assembly 88, the arms 86 and 87, and the rolls 24 and 25 from the retracted position illustrated in FIGS. 7, 8, and 9 to an extended position wherein the rolls 24 and 25 have diameters which are aligned with diameters of the dies 60 and 70. The ram 101 comprises output means for advancing the rolls 24 and 25 to form remaining portions of the ultimate cross section of the article to be formed.

The rolls 24 and 25 as a group have three degrees of freedom with respect to the frame and two degrees of freedom with respect to the output end of the second translator means.

OPERATION

A pulley blank, such as the pulley blank 20, is positioned on the die 60 which is dwelling at one side of the working station of the machine. The pulley blank 20 is mounted on the die 60 so that a guide pin 105 extends through the hub 15. Referring now to FIG. 10, a working cycle is initiated by actuating a switch 106 which energizes a four-way solenoid-operated valve 108. When the valve 108 is energized, the piston chamber of the cylinder 58 is connected to a source of fluid pressure 109 so that the ram 57 drives the slide 55 to the right as viewed in FIG. 6. The blank 20 is then positioned below the die 70.

When the slide 55 reaches the end of its travel, a limit switch 110 is operated to energize a timer 111 which actuates a four-way valve 112. The timer 111 remains energized through a predetermined work cycle. When the four-way valve 112 is reversed, the piston chamber of the power cylinder 75 is connected to the source of fluid pressure 109 through a line 113. The ram 74 and its die 70 are driven downwardly toward the die 60 to perform the pulley-forming operation. During the downward travel of the ram 74, a limit switch 114 is actuated to energize the motor 69, which rotates the die 60 that has been brought into axial alignment with the die 70. To prevent the operation of the other motor 69, suitable position-responsive lock-out means (not shown) may be provided to prevent the operation of the motor 69, which is dwelling at a loading station. The switch 114 is energized prior to engagement of the blank 20 by the upper die 70 so that upon engagement of the blank 20 by that die, the die 70 is rotated.

As the die 70 progresses downwardly, the bulge 16 is crushed to form the doubled wall 23. Prior to the completion of this crushing operation, however, and particularly prior to the time when metal would be displaced into the valley 17, the forming rolls 24 and 25 are advanced into the valley 17 in the following manner. Either prior to engagement of the blank 20 by the die 70, or at least prior to the time when metal would be forced into the valley 17, a limit switch 115 is operated by the ram 74. When the limit switch 115 is operated, a four-way valve 116 is operated to connect the piston chamber of the cylinder 102 to the source of fluid pressure 109 through a line 117. The rolls 24 and 25 are driven forwardly until they enter the valley 17.

The crushing operation is completed when the rolls 24 and 25 are within the valley so that the rolls roll within the valley to receive the axial thrust of the bulge 16 as its crushing is completed to form the doubled wall 23. The rolls 24 and 25 keep the valley clear as its shape approaches and conforms to the desired pulley groove cross section. The rolls 24 and 25 are provided with pulley edge defining shoulders 24a and 25a which extend radially inwardly with respect to the pulley to imaginary circles of diameter corresponding to the outside diameters of the sides of the desired pulley groove.

As was previously indicated, the rolls 24 and 25 are laterally fixed with respect to each other, but are pivoted together from the shaft 93. The rolls are axially movable in their blocks 81, 82, 84, and 85. Any eccentricity caused by, for example, variations in the thickness of the as-received sheet stock or variations in the thicknesses caused by the drawing operation are corrected by the rolls 24 and 25. Any excessive thickness in the stock which is encountered by a roll 24 or 25 will cause that roll to ride toward the axis of rotation of the pulley blank to correct such a variation in thickness. The rolls 24 and 25 may tend to pivot together during initial valley contact but after that interval, the forming rolls 24 and 25 will provide a pulley groove having its center of rotation at the rotational axis of the pulley blank.

After the timer 111 indicates the completion of a working cycle, the valve 112 is returned to the position illustrated in FIG. 10 to retract the ram 74 and thereby raise the die 70. As the ram 74 is retracted, the limit switch 115 is again actuated to return the valve 116 to the position illustrated in FIG. 10. The rolls 24 and 25 are retracted. Further upward travel of the ram 74 trips the switch 114 to stop the operation of the operating motor 69.

During the foregoing forming operation, a completed pulley has been removed from the loading station and a pulley blank is loaded onto the die 60 which is dwelling at the loading station. When the ram 74 reaches the upward limit of its stroke, therefore, the cycle may be repeated by actuation of the switch 106.

The invention is not restricted to the slavish imitation of each and every detail set forth above. Obviously, techniques and devices may be devised which change, eliminate, or add certain specific details without departing from the scope of the invention.

Claims

I claim:

1. Method for forming a pulley having a pulley groove of given cross section defined by flange wall means connected through the root of the groove, the groove having a given root diameter, comprising providing a pulley blank in the form of a sheet metal cup having an annular bulge in the cup wall and an adjacent flaring wall portion, with a valley defined between said bulge and adjacent flaring wall portion, engaging said flaring wall portion and the side of said bulge remote from said valley with axially movable members and moving said members axially together to crush said bulge and form it into a doubled wall, positioning a group of at least two groove-forming rolls within said valley and extending radially inwardly to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove and establishing relative rotation between said group of groove-forming rolls and said pulley blank at least while completing said crushing operation with said rolls rolling within said valley to receive the axial thrust of the bulge as its crushing is completed, to keep the valley clear as its shape approaches and conforms to the desired pulley groove cross section, and to form the pulley groove cross section.

2. Method as in claim 1 in which the positioning of an assembly of groove-forming rolls is accomplished by providing an assembly of a pair of forming rolls spaced apart by the root diameter of the desired pulley groove cross section, and translating said assembly laterally into the work piece whereby said rolls tangentially approach diametrically opposite sides of said valley.

3. Method as in claim 2 in which said assembly is allowed to float transversely to its feed direction while it is translated into the work piece.

4. Method as in claim 2 in which the rolls are allowed to float along the axial direction while they are translated into the work piece.

5. Method as in claim 4 in which the rolls are allowed to float independently of each other.

6. Method as in claim 1 including providing pulley edge defining shoulders on said groove-forming rolls and extending said shoulders radially inwardly to imaginary circles of diameter corresponding to the outside diameters of the sides of the desired pulley groove.

7. Apparatus for forming a pulley having a pulley groove of given cross section defined by flange wall means connected through the root of the groove, the groove having a given root diameter, from a pulley blank in the form of a sheet metal cup having an annular bulge in the cup wall and an adjacent flaring wall portion, with a valley defined between said bulge and adjacent flaring wall portion, comprising axially movable members for engaging said flaring wall portion and the side of said bulge remote from said valley, means for moving said axially movable members together to crush said bulge and form it into a doubled wall, a group of at least two groove-forming rolls, means to move said groove-forming rolls tangentially with respect to said cup to a position within said valley so that said rolls extend radially inwardly to an imaginary circle having a diameter equal to the root diameter of the desired pulley groove, means to establish relative rotation between said group of groove-forming rolls and said pulley blank at least while completing said crushing operation so that said rolls roll within said valley to receive the axial thrust of the bulge as its crushing is completed, to keep the valley clear as its shape approaches and conforms to the desired pulley groove cross section, and to form the pulley groove cross section.

8. Apparatus according to claim 7 wherein said group of rolls comprises an assembly of a pair of forming rolls spaced apart by the root diameter of the desired pulley groove cross section, and wherein said means to move said forming rolls translates said assembly laterally into the work piece, whereby said rolls tangentially approach diametrically opposite sides of said valley.

9. Apparatus according to claim 8 in which said assembly is provided with means permitting floating transverse to its direction of feed while it is translated into the work piece.

10. Apparatus according to claim 8 wherein said assembly includes means permitting axial floating of the rolls as they are translated into the work piece.

11. Apparatus according to claim 10 wherein the rolls axially float independently of each other.

12. Apparatus according to claim 7 wherein said groove-forming rolls are provided with pulley edge defining shoulders and wherein said shoulders extend radially inwardly to imaginary circles of diameters corresponding to the outside diameters of the sides of the desired pulley groove when said rolls are moved within said valley.

13. Apparatus for forming a circular article from sheet metal comprising axially opposed first and second die means, pressure means to move at least one of said first and second die means so that the die means are moved together toward a final apposition at which they define a die cavity corresponding to portions of the ultimate cross section of the article to be formed, forming means cooperating with said first and second die means to form remaining portions of said ultimate cross section encompassing said first-named portions, said remaining portions of the ultimate cross section being radially outward of said first-named portions, said forming means comprising roll die means, said roll die means comprising an assembly of a pair of forming rolls spaced apart by the minimum outside diameter of said remaining portions of said ultimate cross section, means to drive at least one of said die means to establish relative rotative movement between the roll die means and an article being formed, means to advance said roll die means to a position forming said remaining portions of said ultimate cross section of the article prior to the attainment of said final apposition of said first and second die means, said roll advancing means being adapted to translate said assembly laterally into the article, whereby said rolls tangentially approach diametrically opposite sides of said remaining portions of said ultimate cross sections.

14. Apparatus according to claim 13 in which said assembly is provided with means permitting transverse floating in its feed direction while it is translated into the work piece.

15. Apparatus according to claim 13 wherein said assembly includes means permitting axial floating of the rolls as they are translated into the work piece.

16. Apparatus according to claim 15 wherein the rolls float independently of each other.

17. Apparatus according to claim 13 wherein said article is circular, and said roll die means are provided with shoulders which define part of the said remaining portions of said ultimate cross section.

18. Apparatus for forming a pulley having a body portion and having a pulley groove of given cross section extending circumferentially around said body portion and defined by first and second flange wall means connected through the root of the groove, the groove having a given root diameter, from a pulley blank in the form of a sheet metal cup having an annular bulge in the cup wall and an adjacent flaring wall portion, with a valley defined between said bulge and adjacent flaring wall portion, comprising a frame, an axially rotatable lower die mounted on said frame, an axially rotatable upper die axially aligned with said lower die, ram means for said dies, drive means for rotatively driving at least one of said upper and lower dies, said upper and lower dies having surfaces which, when moved together, define and form the body portion of the pulley, a roller assembly slidable on said frame toward the locus of said upper and lower dies when they approach closed position, said roller assembly comprising a pair of rollers having upper and lower edge surfaces which respectively define (with portions of the upper and lower dies respectively) said first and second flange wall means, means to advance said assembly toward said locus so that said roller edges enter said valley, said advancing means moving said assembly so that said rollers enter said valley prior to the complete formation of the body portion of the pulley by the upper and lower dies, said roller assembly further comprising means mounting said rollers so that the periphery-to-periphery distance between said rollers is fixed and corresponds to said given root diameter.

19. Apparatus as in claim 18, said roller mounting means being pivoted with respect to said frame.

20. Apparatus for forming a pulley having a pulley groove of given cross section defined by flange wall means connected through the root of the groove, the groove having a given root diameter, from a pulley blank in the form of a sheet metal cup having an annular bulge in the cup wall and an adjacent flaring wall portion, with a valley defined between said bulge and adjacent flaring wall portion comprising a frame, axially opposed first and second die means on said frame, first translator means having output means for advancing at least one of said first and second die means so that the die means are translated together toward a final forming position which defines a die cavity corresponding to portions of the ultimate cross section of the article to be formed, forming means on said frame cooperating with said first and second die means to form remaining portions of said ultimate cross section, said forming means comprising a group of two roller dies, second translator means having output means for advancing said forming means to a position forming said remaining portions of the ultimate cross section of the pulley, both said first and second die means having less than three degrees of freedom with respect to the frame, at least one of said first and second die means having more than zero degrees of freedom with respect to the frame, said at least one die means having zero degrees of freedom with respect to said output means of said first translator means, said group of two roller dies having three degrees of freedom with respect to the frame and two degrees of freedom with respect to the output end of said second translator means, said roller dies having less than two degrees of freedom with respect to each other during the forming operation and having their axes fixed with respect to each other to establish the desired root diameter.

21. Apparatus as in claim 20, said roller dies having one degree of freedom with respect to each other.

22. Apparatus for forming an article from sheet metal, comprising axially opposed first and second die means, pressure means to move at least one of said first and second die means so that the die means are moved together toward a final apposition at which they define a die cavity corresponding to portions of the ultimate cross section of the article to be formed, forming means cooperating with said first and second die means to form remaining portions of the ultimate cross section encompassing said first-named portions, said forming means comprising roll die means, means to drive at least one of said die means to establish relative rotative movement between the roll die means and an article being formed, means advancing said roll die means to a position wherein prior to the attainment of said final apposition of said first and second die means said roll die means forms said remaining portions of said ultimate cross section of the article.

23. Method for forming an article from a blank in the form of a metal cup comprising the steps of providing a metal cup, positioning said cup between axially opposed first and second die means, moving at least one of said first and second die means so that the die means are moved together toward a final apposition at which they define a die cavity corresponding to portions of the ultimate cross section of the article to be formed, providing forming means cooperating with said first and second die means to form remaining portions of said ultimate cross section encompassing said first-named portions, said forming means comprising roll die means, establishing relative rotative movement between the roll die means and the metal cup, and advancing said roll die means to a position forming said remaining portions of the ultimate cross section of the article prior to the attainment of said final apposition of said first and second die means.