CA1219741A - Machine and method for manufacturing universal joints - Google Patents

Abstract

MACHINE AND METHOD MANUFACTURING UNIVERSAL JOINTS

ABSTRACT OF THE DISCLOSURE
This invention relates to metal cutting and more particularly to machines for manufacturing constant velocity universal joints. A construction is disclosed wherein spherical turning, milling and grinding of the races and grooves of the joint members of a universal joint are performed on common machines without removing the workpieces and the workpieces are held in common workheads. During the machining operations relative movements between the tools and workpieces are referenced to common axes thereby duplicating the relative positions and movements between the workpieces during actual service. The inventive concept provides a means for achieving consistent product quality and is adaptable to the automated manufacturing of constant velocity universal joints.

Description

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13 BAC~ ou,~n OF IE~E INVENTJON
l4 Worldwide demand for front and four w~eel drLve vehicles has created an Increasing demand for constant velocity universal joLnts. The L6 Rzeppa joirlt, used almost exclusively at the outer ends of front axles, L7 ls exemplary of this type of joint.
L8 Named for lts inventor, A. H. Rzèpp-a, it consists of an outer race L9 member, an inner race member, a ball cage and generally six driving ba]ls.
~0 The matlng surfaces between the members are spherical in shape and close ~1 fitting to one another, The driving balls flt into corresponding half grooves ~2 of the lnner and outer races, the grooves having meridian lines of a sphere 23 as ~heir centerlines. The construction and function of the Rzeppa joint are ~4 more fullydisclosed ln U.S. Patents Nos. 1,916,442 and 1,975,758.
~5 Heretofore~ the manufacture of Rzeppa and similar type joints hasefi required large numbers of speciallzed machines for spherical turning, m~lling 27 and grinding of the races and ball grooves. Consequently, large investments 28 have been required which were ~eco~ered as part of the purchase price of the .
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universal joint. Also, separate and specialized machines for each of the machining operations has made difficult the maintenance of precision tolerances.
One object of the present invention is to advance the art of metal cutting, particularly the manufacture of Rzeppa and similar type universal joints.
Another object is to provide machines and methods for manufacturing universal joints wherein machining opera-tions for close fitting races and mating and corresponding surfaces of joint components are performed on the same machines without removing the workpieces and held in common workheads.
Another object is to provide machines and methods for manufacturing universal joints wherein relative movements between the workpieces and cutting tools, during the spherical machining of races and ball grooves, are referenced to common axes thereby duplicating the relationships between -the work-pi.eces during actual use.
Generally speaking, the present invention may be considered as providing a method for manufacturing universal joints of the type employing conjugate members having close fitting conforming surfaces comprising mounting each of the conjugate members in a common workhead during the machining thereof, imparting the same relative motions between the con-jugate membexs and cutting tools as exist durin~ the actual service of the members, engaging the cutting tools with the members and generating the close fitting conforming surfaces of the members by the cutting actions of the tools~

Generally speaking, the above method may be carried out by way of a machine for making universal joints wherein multiple machining operations are perforr,led on corresponding members of a universal joint, held in a common wGrkhead and revolved about common axes conforming to the universal joint comprising: a base; a workhead rotatably carried on the base;, the wor]chead having a housing, a spindle rotatably mounted in the housing, the axis of the spindle being in perpendicular and intersecting relationship to the workhead axis, and a workholder attached to one end of the spindle for holding corresponding members of a universal joint and moving the members with the same motion as the spindle such that the members revolve about axes conforming to the universal joint;
a means for swiveling the workhead about the axis thereof;
a means for revolving the sp.indle about the axis thereof; a means Eor indexing the spindle about the axis thereof; a m~ans for locking the spindle to the workhead housing; a longitudinal tool slide table carried on the base for move-ment parallel to the spindle axis; a means :Eor moving the longitudinal tool slide table; a tool index table carried on the longitudinal tool slide table for supporting a plurality of machining stations; a means for rotatably indexin~ the tool index table about the axis thereof; a plurality of machining stations mounted on the tool index table, each of the stations having a cutting tool for machining a workpiece held in the workholder; and a means for controlling the motions of the workholder and cutting tools of the machining stations.
The foregoing objects, along wi-th additional objects, features, advantages and benefits of the invention become more apparent ln the ensuing description and accompanying drawings which disclose the invention in detail. A preferred embodi-men-t is disclosed in accordance with the best mode contem-plated in carrying out the invention. The subject matter in which an exclusive property is claimed is set forth in each of the number claims at the conclusion of the description.

~RIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a more or less diagrammatic plan view of a machine for manufacturing universal joints embodying the principles of my invention.
Fig. 2 is a front elevation view of the same machine.

lcm/ ~ ~ -2b-Fig, 3 is a right side elevation vlew of the same machlne.

2 Flg. 4 is a left side elevation view of the same machine.

3 Fig. 5 is a partlal plan view drawn to an enlarged scale from

4 Flg. 1 depicting the relative positlons of the work station and turning stations dur~ng a spherical turning operation of the machine.
6 Fig. 6 is a partial front el~vation vlew drawn to an enlarged 7 scale from Fig. 2 depicting the relative positipns of the work station and miLling station during a spherical milling operation of the machine.
9 FLgs. 7 and 8 are horiæontal sectional views taken along the line 7-7 of Flg. 1, drawn to an enlarged scale and depicting spherical I.D.
11 tlLrning of a universal joint outer race.
12 Figs. 9 and 10 are similar views to Figs. 7 and 8 depicting 13 mLlling of a ball groove in a universal joint outer race.
14 Figs. 11 and 12 are similar views to Figs. 7 and 8 depicting spherLcal I.D. grinding of a un~versal joint outer race.
16 Figs. 13 and 14 are similar views to Figs. 7 and 8 depicting 17 grlnding of a ball ~roove in a universal joint outer race.
18 Figs. 15 and 16 are similar views to Figs. 7 and 8 depicting 19 spherical O.D. turning of a universal joint ball cage.
Figs. 17 and 18 are similar views to Figs. 7 and 8 depicting 21 spherical I.D. turning of a universal joint ball cage.
22 Figs. 19 and 20 are similar views to Figs. 7 and 8 depicting 23 spherical O.D. grinding of a universal joint ball cage.
24 Figs. 21 and 22 are similar views to Figs. 7 and 8 depicting spherical I.D. grinding of a universal joint ball cage.
26 Figs. 23 and 24 are views similar to Figs. 7 and 8 depicting 27 spherical O~ D. turning of a unlversal joint inner race .
28 Figs, 25 and 26 are views similar to Figs. 7 and 8 depicting 29 milling of a ball groove in a universal joint inner race.
Figs. 27 and 28 are views similar to Figs. 7 and 8 depicting 31 spherical O.D. grindlng of a universal joint inner race.

lZ1 374 1 Flgs. 29 and 30 are views similar to Figs. 7 and 8 depicting 2 grlnding of a ball groove ln a universal joint inner race.

4 With reference to the accompanying drawings, a preferred embodiment of my invention of a machine Is shown which is particularly 6 directed ~o the manufacture of universal ioints of the type which incorporate 7 components having spherical surfaces with common axes and centers of 8 curvature. It will be observed that In these types of assemblies, 9 corresponding and mating surfaces of the separate components must be machined to very close tolerances and conformity of shape in order to meet 11 the requirements of the user.
12 Heretofore, the aforedescribed kinds of universal joints have 13 been made by two types of methods. Single and low volume production 14 has been accomplished by general purpose rnachlnes while large volume '~
production has been on special purpose machines which perform single ~ -16 machinlng operations and generally incorporate multiple workheads.
lY With the instant invention the exacting machining operatLons for 18 the spherical surfaces and ball grooves oE the indlvidual components are 19 performed on common machLnes, referenced to common axes and generated about common centers without removing the workpieces. Thus, with my 21 lnvention a slngle workhead is provided in combination with multiple tool 22 heads on a common machine.
23 From the ensuing detailed description it will be noted that 24 several noteworthy benefits are derived from the instant invention. The 7 referencing of the machining for the spherical surfaces and ball grooves 26 to common axes and the generativn of surfaces without removing the work-27 piece results in improvements in conformity of corresponding and mating 28 surfaces and control of product quality. Also, a single work station in 2g combination with multiple machining stations facilitates control of product 7.
quality by providLng common locating points for the workpiece in the ~æ~
workhead durin~ machining operations and is readily adaptable to efficient and ~nodeln methods of automated production, such as, numerical or other systems of automated control. It will be further observed that the instant invention is highly versatile and ~ay be ~mployed as a single machine for proto-type and low volume production or in numbers for high volume production.
In the drawings wherein like numerals refer to like and corresponding parts t~.roughout the several views, the preferred embodiment is shown in the machine comprising a single work station 41 and a group of machining stations 39, preferably powered b~ electric motor drives, and mounted for rotation and translation on a base 40. The machine is universal in construction, whereby a wide range of sizes and types of unive.rsal joints can be machined by adjustments and minor modificati.ons to the cuttina tools and work holding devices thereof. The control of the machine may be manual or alternatively auto~.atic by the use of a control system.
Operator controls are located in the control unit 47 which is mounted to the base 40 by the support member 48. It will be observed that many features of the inventive concept can be embodied in alternate constructions. For example, where the group of machining stations 39 is replaced by a single or group of demountable machinina stations.
The work swivel table 42 is journaled to the base 40 in su.itable bearings, not shown, for rotation about the vertical axis, designated by the numeral 80, and supported by the pair of bearing ring segments 43. The swivel table axis 80 is fixed in space and provides a reference axis for positioning a wor~piece and for generating corresponding and mating surfaces of separate components of a particular ` sd/,~G -5-7~

design of a universal joint assembly. The swivel. table 42 is power driven by the electric motor drive unit 49. The electric motor drive unit 49 is conventional and swivels table 42 back and for_h about the swivel axls 80.
On top of and supported by the swivel table 42 is the work sli.de table 44 which is moveable in a direction perpen-dicular to the axis 80 of the swivel table 42. The work slide table 44, driven by the electric motor drive unit 46, is supported and guided by the pair of V-slide ways 45 or other suitable support and guide meansO

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Suitably mounted to the work slide table 44 is the workhead 50, 2 comprising the spindle housing 51, spindle 55, spindle drive unit 52, spindle 3 indexing unit 53, and work holding device 54~ The spindle 55 is rotatably 4 mounted within the spLndle housing 51 on bearings, not shown, and during the operation of the machine may be either locked Ln position to the housing 51, 6 indexed rotatably by the indexing unit 53 or continuously driven by the spindle 7 drive unit 52. The spindle axis 38 lntersects and is perpendicular to the 8 swivel table axis 80, whereby during movement of the slide table 44 on the 9 swivel table 42 the holding device 54 moves on the swivel table 42 along axLs 38 in radial rela~ionship to the axis 80 of the swivel table 42.
11 A workpiece 58 to be machined is carried in the holding device 54, 12 shown as a conventional chuck 5~, but which may a~ternatively be some other 13 type of holding device, such as, a collet or arbor. The holding device 54 is 14 operatively attached to one end of the spindle 55. ~t the other end of the spindle 55 is the indexing unit 53 which indexes the spindle 55 and attached 16 ~ holdin~ devlce 54 about the spLndle axis 38. The indexing unLt 53 is 17 operatively connected to the spindle 55 by a clutch means, not shown, and 18 is operative only when the spindle 55 is not driven by the electric motor drive 19 unit 52. When the splndle 55 is not driven by the drive unit 52 it is locked in position to the housing 51 by the clutch or some other locking means.
21 Opposite the work station 41 is the group of machining stations 39, 22 comprising the spherical turning station 60, ball groove milling station 59 23 spherical grLnding station 61 and ball groove grinding station 62. The 24 machining stations 39 are mounted in fixed positions on the rotary index table 63 which is rotatable about the axis 37 disposed in a parallel and 26 co-planar relationship to the axis 80 of the work swivel table 42. The rotary 27 Index table 63, suitably journaled and mounted to the cross slide table 65 in 28 ~earings, T~ot shown, Is driven by the electric motor lndexing drive unit 64 29 whereby the separate machining stations 39 and their tools may be properly presented to the workpiece 58 during the machining thereof.
31 Ihe cross slide table 65 is mounted on V-slide ways 66, or other 937L~ 1 suLtable support and guide means, on the longitudinal slide table 68 and 2 driven by the electric motor dri~,_ 67. The cross slide table 65 is 3 oriented and moveable in a direction perpendicular to the axis 37 of the 4 index table 630 The dlrection of movement of the cross slide table 65 is designated in the drawlngs by the arrows 36-36.
6 The longitudlnal slide table 68 which underlies the cross slide 7 table 65 Is mounted on V-slide ways 69, or other suitable support and guide 8 means, on the machine base 40. The table 68 Ls oriented and moveable in a 9 dlrection perpendicular to the axis 37 of the index table 63 and driven by the electric motor drive unit 67 in the direction designated by the arrows 35-35.
11 The dlrections 35~35 and 36-36 are perpendicular to each other.
12 Referring to Fig. 4, the spherical turning station 60 is comprised13 , of the tool holder 71 flxed to the index table 63 and the replaceable cutter 14 li bit 70 held ill the tool holder 71. The cutting edge 57 of ~he cutter bit 70 Is posltioned at the same helght as the workhead splndle axis 38. Thus, 16 ' during movements of the workplece 58, the cutting edge 57 of the cutter 17 bit 70 and workhead spindle axis 38 lie In the same plane and said plane 18 is perpendicular to the swtvel table axis 80 and index table axis 37. It 19 wlll be later noted that the rotational axes of the tools of the milling station 59 and grinding stations 61, 62 are also located in this plane.
21 The cutter bit 70 is engaged with the workpiece 58 by indexing 22 the table 63 to a position whereby the turning station 60 is opposite the 23 workpiece 58 and then advancing the cutter bit 70 in the direction of the 24 workpiece 58 by compound movements of the longitudinal slide 68 and cross slide 65 tables. The depth of cut of the cutter bit 70 is controlled 26 by movement of the cross slide table 65, 27 The construction of the ball groove milling station 59 is best 28 observed ln Fig. 6. The horlzontally disposed milling spinàle 72 is 29 suitably journaled wlthin bearings, not shown, in the housing 73 and rotatably driven by the electric motor drive unit 75. The housing 73 is 31 fixed to ~he index table 63. At the outer end of the spindle 72 is the -- 7 ~

holdlng devLce 76 which carries the milling cutter 74. The rotational 2 axis 56 of the milling cutter 7~ is positioned at the same heLght as the 3 workhead spindle axis 38, co-planar with the spindle axis 38 and 4 perpendlcular to the swivel table axis 80.
Referring to Flg. 1, the spherical grinding station 61 includes 6 the spLndle housing 92 fixed to the index table 63, ~he horizontally disposed 7 spLndle 89 suitably ~ournaled in bearings, not shown, within the housing 92, 8 the tool holder 90 aligned with and attached to the outer end of the 9 splndle ~9, the grLnding tool 91 and the electric motor drive unit 88 for rotatLng the spindle 89.
11 The spherical end of the grinding tool 91 ls shaped and sized to 12 produce the finished profile of the spherical race of a joint member.
13 Preferably, with the object of minimizing the requirement for replacement 14 and dressing of the grindinçl tool 91, an abraslve material having high wear resistance is used for thc tool 91. An example of a commercially available 16 ' materlal wlth hlgh wear reslstance is the abraslve marketed under the 17 tradename Borazon. The horizontal rotatlonal axis 111 of the spindle 89 and 18 thereby th~ grindlng tool 91 are at the same height as the workhead spindle 19 axis 38, thus lying in the same plane as the workhead spindle axis 3S
and perpendlcular to the swlvel table axis 80.
21 The conskuction of the ball groove grinding station 62 is similar 22 to the spherical grinding station 61, except for the speed ratio of the 23 electric motor drive unit 9~ which provides the proper surface speed for 24 grinding the ball grooves, and preferably the shape of the grindlng tool 97 .
The spindle 95 is suitably journaled within bearings, not shown, in the 26 housing 96 which is fixed to ~he index table 63. The tool holder 98 which 27 is aligned with and attached to one end of the spindle 95 carries the ball 28 groove grindlng tool 97, the axis 110 of the grinding tool 97 also being the 29 axls of the spindle 95. The electric motor drive unit 9~1 Is attached to the other end of the spindle 95.
31 The horizontal rotational axis 110 of the ball groove grinding l' l spindle 89 is at the same height as the workhead spindle axis 38 thereby 2 lylng in the same plane as the workhead spindle axis 38 and perpendicular 3 to the swivel table axis 80. An abrasive rnaterial with high wear resistance 4 is also preferred for the ball groove grLnding tool 97~
In applying the present invention it will be observed that In 6 order to achieve the exactlng tolerances which are required for the separate 7 members of a universal ~oint, the machlne herein described must be 8 constructed with care and accuracy such that the cutting edge 57 of the 9 cutter bit 70, and rotational axes of the milling cutter 74 and grinding tools 91, 97 are posltioned at the same height and lLe in the same plane 11 as the axis 38 of the workhead splndle 55. It will also be observed that 12 the foregolng condition must be met during the aforedescribed motions of 13 the other members, such as, the work sv~livel table 42 of the machine.14 The followLng descriptLon of spherlcal and ball race machiningof a set of universal Jolnt components further describes the features and 16 use of the present inventlon.
17 ` Referring to Figs. 7 and 8, the outer member 77 of a Rzeppa type 18 universal ~oint is shown in the worlchead 50 during spherical turning of the 19 outer r~ce 78. The workpiece 77 is accurately located ln the workhead 50 by clamping ~e outer diameter of the workpiece 77 in the jaws 79 of the 21 holding device 54, butting the shoulder 81 of the workplece 77 against the 22 shoulder stop 82 of the workhead 50 and enç~aging the key 83 of the holding 23 device 54 with the keyway 84 of the workpiece 77. Thus, it is seen that the 24 workpiece 77 has bean accurately allgned and positioned in axial and radial directions with respect to the axis 38 of the workhead spindle 55.
26 In Fig. 7 the positions of the workhead 50 and turning station 60 27 are shown at the beginning of spherical I.D. turning of the outer race 78.
28 As will be observed, the workhead 50 has been revolved about the swivel 29 table axis 80 and the cutter bit 70 engaged with the workpiece 77 by advancing the longltudinal slide table 68 and then moving the cross slide 31 table 65 to set the depth of cut. During spherical turning, the workpiece 77 i l .. i 7~1 ., :
is rotatably drlven by the drive unlt 52 about the work spindle axis 38 and 2 swiveled by the swivel table 42 about ~he table axis 80 to th0 final position 3 shown in Fig. 8. If necessary, further cuts are taken in the aforedescribed 4 mannes to complete the turning of the outer race 78.
S After spherical ~urning ~he outer race 78, the cutter bit 70 ls 6 wlthdrawn from the workpiece 77 by movements of the cross sllde 65 and 7 longitudinal slide 68 tablesO The spindle 55 is positioned by the indexing 8 unit 53 and lodged in place to prepare for the next operation of milling the 9 ball grooves 87 of the workpiece 77. It will be observed that for ball groove milllng the workpLece 77 is not removed from the holding device 54 used 11 for spherical turning.
12 Referring now to Fig. 9 wherein the initial positions of the 13 workpiece 77 and milling cutter 7~ are shown for ball groove milling, the 14 workpiece Y7 is initially positloned by swiveling the table 42 and dLsplacing the work slide table 44 Erom the position used for spherical turning in an 16 amount equal to the offset 86 in the workpiece 77 between the cènter of 17 curvature S5 of the outer race 78 and the center 34 of the meridians of the 18 ball grooves 87. Thus, the workpiece 77 has been re-Rsitioned to place 19 the center 34 of the meridians of the. ball grooves 87 to be machined on the axis 80 of the work swivel table 42. The milling station 59 is moved 21 opposite the workpiece 77 by indexing the rotary~table 63 and the milling 22 cutter 74 engaged with the workpiece 77 by advancing the longitudinal 23 slide table 68 and then moving the cross slide table 65 to set the depth of 24 the milling cut.
During the milling of a ball groove 87, the milling cutter 74 is 26 rotatably driven by the drive unlt 75 as the workpiece 77 is swiveled by the 27 table 42 about the table axis 80 to the final position shown in Fig. 10. If 28 necessary, further milling is done in the aforedescribed manner to complete 29 the ball groove 87. After the ball groove 87 has been completed, the milling cutter 74 is w~thdrawn irom the workp~ece 77, by a movement of the 31 longitudinal slide table 68, and the workpiece 77 is rotatably indexed by the ~1 ~

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i indexing unLt 53 for milling the next ball groove 87. The spindle 55 is then 2 ;; locked to the housing 51 the mllling cutter 74 re-engaged with the 3 workpiece 77 and the nex~ ball groove 87 milled in the aforedescribed 4 manner. The sequence is repeated for the remaining ball grooves 87.
S Following ball groove milling the workpiece 77 is preferably 6 removed from the holding device 54 and heat treated. After heat treating 7 the workpiece is re-mounted in the same position in the holding device 54 8 with the help of the key 83 for grinding the outer race 78 and ball grooves 87 9 to their finished siæes.
Referring to Fig. 11 the workpiece 77 and spherical grinding 11 tool 91 are shown at their initial positions for the operation of spherical 12 grinding the outer race 78. The workpiece 77 is Initially positioned by 13 sw~veling the table 42 and dlsplacing the work slide table 44 to place the 14 center of curvature 85 of the outer race 78 on the axis 80 of the swivel ~5 table 42 The posltLon of the work slide table 4~ for spherical grinding is 16 the same as for spherical turning. The grinding station 61 is moved 17 ~ opposite the workpiece 77 by indexing the rotary table 63 and the grinding 18 tool 91 engaged wLth the workpLece 77 by advancing thq longitudinal slide 19 table 68 and moving the cross slide table 65 to set the depth of the grind.
During spherical grLnding of the outer race 78, the grinding 21 tool 91 Ls rotated by the drive unit 88 as the workpiece 77 is rotatably 22 driven by the drive unLt 52. about the work spindle axis 38 and swiveled 23 by the table 42 about the table axLs 80 to the final position shown in Fig. 12.
24 If necessary further grLnding is done in ~he aforedescribed manner for the fLnLshed sLæe of the outer race 78. The grLnding tool 91 is then withdrawn 26 from engagement with the workpiece 77 by movements of the cross slide 27 table 65 and longitudinal slide table 68 to begin the next operation of 28 grinding the ball grooves 87 to their finished si2es.
29 After spherical grinding the outer race 78, the spindle 55 is positioned by the indexing unit 53 and locked ln place to prepare for the next 31 operation of ball groove grinding. The work slide table 44 is then returned Il i l; :
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to the same position as ball groove milling whereby the center 34 of the ball groove meridians Is on the axis 80 of the work swlvel table 42.
3 Referring now to Fig. 13, the initial positions of the workpiece 77 4 and ball groove grinding tool 97 are shown for ball groove grinding. The workpiece 77 is swiveled about the axis 80 by the swivel table 42 and the 6 ball gros)ve grinding station 62 brought into position by indexing the rotary 7 table 63. The grinding tool 97 is engaged with the ball groove 87 of the 8 workpiece 77 by advancing the longitudinal slide table 68 and moving the 9 cross slide table 65 to set the depth of the grind. During grinding, the grinding tool 97 is rotatably driven by the drive unit 94 as the workpiece 77 11 is swiveled by the table 42 about the table axis 80 to the final position 12 shown in Fig. 14, If necessary, further grinding is done in the aforedescribed 13 manner to finish the ball groove 87. The. grinding tool 97 is then withdra~Jn ~1 from engagement with ~he workpiece 77, by movements of the cross slide table 65 and longitudinal slLde table 68, and the workpiece 77 is rotatably 16 indexed by the indexiny unit 53 about the axis 38 to the position of the next 17 ball groove 87. The spindle 55 is then locked to the housing 51, the 18 grinding tool 97 re-engaged with the workpiece 77 and the next ball groove 87 19 ground in the aforedescribed manner. The sequence is repeated for the remaining ball grooves 87.
21 Referring to Figs. lS and 16, the finished outermember 77 has 22 been removed from the ma~hine and the ball cage member 108, supported 23 on the arbor 104, mounted Ln the workholder 54. The operation to be 24 performed is spherical O.D. turning of the workpiece 108. It will be observed after the subsequent grinding of the workpiece 108 that the finished 26 outer contour of ball cage member 108 conforms to the contour of the outer 27 race 78 of the outer member 77~
28 The workpiece 108 is clamped to the end portion OI the arbor 10A
29 by the washer 102 and clamp nut 99 which is in threaded engagement with the arbor 104. The arbor 104 Is al~gned with the spinclle 55 by the jaws 79 31 of the workholder 54 and located Ln the direction of the splndle axis 38 by "
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butt~ng the arbor shoulder 101 against the workhead shoulder stop 82. The 2 constructLon of the arbor 104 preferably positions the center of curvature 85, 3 of the surface to be machlned, on the swivel table axis 80 when the work sllde table 44 is positioned at the same location used during spherical machining of the outer race 78 of the member 77.
The workpiece 108 is initially positioned as shown in Fig. 15 by 7 swiveling the table 42 about the table axis 8Q and moving the work slide 8 table 44 to positlon the center of curvature 85 of the surface to be machined 9 onto the swivel table axis 80. The turning station 60 is then moved into position by indexing the rotary table 63 and the cutter bit 115 engaged with 11 the workpiece 108 by advancing the longitudinal slide table 68 and then 12 moving the cross slide table 65 to set the depth of cut of the cutter bit 115.
13 During spherical turning, the workpiece 108 is rotatably driven by the 14 drive unit 52 about the spindle axis 38 and swiveled by the table 42 about the table axis 80 to the final position shown in Fig. 16. If necessary, 16 further cuts are taken in the aforedescribed manner to size the spherical 17 ~ O.D. of the workpLece 108.
18 Referrinçl to Figs. 17 and 18, the workpiece 108 has been removed 19 from the arbor 104 and mounted on the arbor 112 which is carried in the I workholder 54. The interior of the arbor 112 is shaped to receive the outer 21 contour of the workpiece 108 and the workpiece 108 is clamped to the 22 arbor 112 by the clamp nu~ 105 which is in threaded engagement with the 23 end portion of the arbor 112. An alternative means, not shown, for holding 24 the workpiece 108 during spherical I.D. turning and grinding is unhardened chuck ~aws having a conforminç~ contour for clamping the workpiece 108 26 within the jaws. It i5 apparent that with the alternative holding method the 27 conformlng contour can be machined in unhardened jaws of the workholder 54 28 by the use of the present invention.
29 The workplece 108 Is initially positioned as shown in Fig 17 by swiveling the table 42 about the table axis 80 and moving the work slide 31 table 44, if necessary, to position the center of curvature 85 of the ~nner li i surface to be machined on the swivel table axis 80. The turning station 60 2 is moved into position by indexing the rotary table 63 and the cutter bit 109 3 engaged with the workpiece 108 by advancing the longitudinal slide table 68 4 and moving the cross slide table 65 to set the depth of cut of the cutterS b~t 109. The workpiece 108 is then swiveled about the axis 80 by the swivel 6 table 42 and rotatably drlven about the spindle axis 38 by the drive unit 52 7 to the final position shown in Fig. 18. If necessary, further cuts are taken 8 In the aforedescrlbed manner to complete the spherical I .D. turning of the 9 workplece 108.
Following the spherical I.D. turning, the workpiece 108 is 11 preferably removed from the arbor 112 and holding device 54 for machining12 the ball slots in the workpiece 108 and heat treatlng. ~fter these operations 13 are completed, the workpiece 108 is returned to the machine for grinding 14 the spherical outer and inner surfaces to their finished sizes~
Referring now to Fig. 19, the workpiece 108 and grinding tool 116 16 are shown in their Lnitial positions for spherical O.D. grinding of the ball 17 cage member 108. The workpiece 108 has been re-mountecl on the arbor 1C)418 which is carrled in the workholder 54. The workpiece 108 is initially 19 posltloned by swiveling the tahle 42 and displacing the work slide table 44 to place the cerrter of curvature 85 of the outer surface on tl e axis 80 of the21 swlvel table 42. The grinding station 61 is brought into position by indexing 22 the rotary table 63 and the grinding tool 116 engaged with the workpiece 108 23 by advancing the longltudinal slide table 68 and moving the cross slide 24 table 65 to set the depth of cut of the grinding tool 116. The grinding tool 116 is rotatably driven by the drive unit 88 as the workpiece 108 is rotatably 26 driven by the drive unit 52 and swiveled by the table 42 about the axis 80 27 to the fLnal position shown in Flg~ 20. If necessary, further grinding is done 28 in the aforedescribed manner to complete the spherical O.D. grinding of the 29 workpiece 108.
Aiter the spherical O.D. grinding has been completed, the 31 workpiece 108 is transferred to the arbor 112 which was previously used for J

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spherlcal I.D. turning and mounted with the arbor 112 Ln the workholder 54 2 for spherical I.D. grinding. The initial posltions of the workpiece 1083 and grinding tool 119 are shown in Fig. 21. The workpiece 108 is initially 4 positioned by swiveling the table 42 about the axis 80 and moving the work S slide table 44, if necessary, to position the center of curvature 85 of the 6 Inner surface on the axis 80 of the swivel table 42. In the event the 7 grlnding station 61 has been moved from the position of spherical O.D.
8 grinding, it is returned opposite the workpiece 108 by indexing the rotary 9 table 63. The grinding tool 119 is then engaged with the workpiece 108 by advancing the longItudinal slide table 68 and moving the cross slide 11 table 65 to set the depth of grind of tile tool 119. The grinding tool 119 12 is rotatably drlven by the drive unit 88 as the workpiece 108 is rotatably 13 driven by the drive unit 52 and swiveled by the table 42 about the table 14 axis 80 to the final position shown In FicJ. 22.
Referring now to Fi~s. 23 and 24, the ball cage member 108 has 16 been removed from the machine and the inner member 123 carried on the 17 arbor 122 mounted in the workholder 54. The operation to be performed on 18 the workpiece 123 is spherlcal O.D. turning of the inner race 124. The 19 workpiece 123 Is clamped to the end portion of the arbor 122 by the spacer 121 and clamp nut 120 which is in threaded engagement with the end of the 21 arbor 122. The center portion of the arbor is splined to receive the internal 22 spline of the workpiece 123. The workpiece 123 is angularly located on the 23 arbor 122 by some means, riot shown, such as engaging a wide tooth of the 24 arbor spline with a wide space of the workpiece spline. The arbor 122 is preferably constructed to position the center of curvature 85, of the inner race 124 to be machined, on the swiYel table axis 80 when the work slide 27 table 44 is positioned at the same location used during spherLcal machining 28 of the outer race 78 of the member 77. The arbor 122 is located within the 29 workhead 50 by the chuck jaws 79, engaging the key 83 of the holding device 54 with the keyway 129 of the arbor 122 and butting the shoulder 117 31 of the workpiece 123 against the shoulder stop 82 of the workhead 50.

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The workpiece 123 is initially positioned by swiveling the 2 $able 42 about the axis 80 and moving the work slide table 44 to position the 3 center of curvature 85 of the inner race 124 to be machined on the axis 80 of the swivel table 42. The turning station 60 is moved into position by S lndexing the rotary table 63 and the cutter bit 125 engaged with the 6 workpiece 123 by advancing the longitudinal slide table 68 and moving the 7 cross slide table 65 to set the depth of cut of the cutter bit 125. During 8 O~D. turning of the inner race 124, the workpiece 123 is rotatably driven 9 about the work spindle axis 38 by the drive unlt 52 and swiveled about the axls 80 of the table 42. If necessary, further cuts are taken to complete the 11 turning of the inner race 124. The final position after O.D. turning is shown 12 ln Fig. 24. The cutter bLt 125 is then withdrawn from the workpiece 123 by 13 movements of the cross slide table 85 and longitudlnal slide table 68 to 14 begln the next operation of milling the ball grooves 127.
The lnitlal positions of the workpiece 123 and milling tool 128 are 16 shown in Fig. 25 for ball groove milling. The workpiece 123 is initially 17 positioned by swiveling the table 42 about the axis 80 and moving the work 18 slide table 44 to position the center 34 of the meridians of the ball grooves 127 19 to be machined on the axis 80 of the swivel table 42. It will be observed that the same arbor 122 and workholder 54 is used for machining the inner 21 race 124 and ball grooves 127 of the inner member 123 without removing the 22 workpiece 123.
23 The milling station is moved into position by indexing the rotary 24 table 63 and the milling cutter 128 is engaged with the workpiece 123 by advancing the longitudinal slide table 68 and moving the cross slide table 65 26 to set the depth of cut of the milling cutter 128. The work spindle 55 is 27 locked in position to the spindle housing 51 during the milling of a ball 28 groove 127. The mLlling cutter 128 is rotatably driven by the drive unit 75 29 as the workp~ece 123 15 swiveled by the table 42 about the table axis 80 to the final position shown In Flg. 26. If necessary, further milling cuts are 31 taken in the aforedescribed manner to complete the milling of the ball I

groove 127. Af~er the groove 127 has been completed, the milling cutter 128 2 is withdrawn from engagement with the workpiece 123 by movements of the3 cross sllde table 65 and longitudinal slide table 68 and the workpiece 123 4 is rotatably indexed by the indexing unit 53 to position the workpiece 123 for milllng the next ball groove 127. The sequence is repeated for the remaining ball grooves 127.
7 Followlng the milling of the ball grooves 127, the workpiece 123 8 is preferably removed from the machine and heat treated. After heat treating 9 the workpiece 123 is re-mounted in the arbor 122 carried in the workholder 54 Eor grinding the inner race 124 and ball grooves 127 of the workpiece 123.
11 Referring now to Fig. 27, the workpiece 123 and grinding tool 129 12 are shown in their initial positions spherical grinding of the inner race 124.
13 The workpiece 123 is initially positioned in the same manner as during 14 spherlcal turning whereby the workpiece 123 is swiveled by the table 42about the axIs 80 and the work sllde table 44 is moved to position the 16 center of curvature 85 of the inner race 124 on the axls 80 of the swivel 17 table 42. The grinding tool l29 is engaged with the workpiece 123 by 18 advancing the longitudinal slide table 68 and moving the cross slide table 65 19 to set the clepth of the grinding cut. During spherical grinding, the grinding tool 129 is rotatably driven by the drive unit 88 while the 21 workpiece 123 is rotatably driven about the axis 38 by the drive unit 52 and 22 is swiveled by the table 42 about the table axis 80 to the position shown in 23 Fig. 28. If necessary, further grinding is done in ths aforedescribed manner 24 to complete the spherical grinding of the inner race 124.
The initial positions of the workpiece 123 and hall groove grinding 26 tool 130 are shown in Fig. 29 for the operation of grinding ball grooves 127 27 of the inner member 123. The workpiece 123 is initially positioned by 28 swiveling the table 42 about the table axis 80 and moving the work slide 29 table 44 to position the center 34 of the meridians of the ball grooves 127 on the axls 80 of the swivel table 42. The grinding station 62 is brought into 31 positlon by Indexing ~he rotary table 63 and the grlnding tool 130 engaged 1, 1 f' I ' ~. 2~L~ '7 L,~

. ' .
with the workpiece 123 by advancing the longitudinal sllde table 68 and 2 moving the cross slide table 65 to set the depth of the grind. The work 3 spindle 55 Ls positioned by the indexing unit 53 and locked in place to 4 position a ball groove 127 for finished grinding. During ball groove grinding, ; the grlnding tool 130 is rotatably driven by the drive unit 94 as the 6 ~ worlcpLece 123 Is swiveled by the table 42 about the axis 80 to the final 7 position shown in FLg. 30. If necessary, fu~ther grinding is done in the 8 aforedescribed manner to complete the ball groove 127. The grinding 9 tool 130 is then withdrawn from engagemen~ with the workpiece 123, by a movement of the longitudLnal slide table 68, and the workplece 123 rotatably 11 indexed by the indexing unit 53 to the position of the next ball groove 127.
12 The spindle 55 is then locked in position to the housing 51, the grinding 13 tool 130 re-engaged with the workpiece 123 and the next ball groove 127 14 ground in the aforedescribed manner. The sequence is repeatecI for the remaining ball grooves 127.
16 From the foregoing detailed description, it is apparent thatthe 17 Instant invention provides a machine which is particularly adapted to the 18 manufacture of universal joints and has numerous features and advantages, 19 " such as, reduced investment costs, adaptability to automated systems of production, and improved maintenance of tolerances, fit and conformity of 21 the separate members of a joint assembly. It is also apparent from among the 22 numerous advantages of the invention, that a wide range of sizes and types 23 of universal joints can be machined with the invention by adjustments, 24 modifications to the cutting tools and work holding devices and variations in the motions of the elements thereof.
26 Although but a single embodiment of the invention has been 27 described in detail, Lt is obvious that many changes may be made in the 28 size, shape, arrangement and details of the various elements of the invention 29 without departing from the spirit thereof.

I claim:

'I ~

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

A machine for making universal joints wherein multiple machining operations are performed on corresponding members of a universal joint, held in a common workhead and revolved about common axes conforming to the universal joint comprising: a base; a workhead rotatably carried on the base, said workhead having a housing, a spindle rotatably mounted in the housing, the axis of said spindle being in perpendicular and intersecting relationship to the workhead axis, and a workholder attached to one end of the spindle for holding corresponding members of a universal joint and moving the members with the same motion as the spindle such that the members revolve about axes conforming to the universal joint; a means for swiveling the workhead about the axis thereof; a means for revolving the spindle about the axis thereof; a means for indexing the spindle about the axis thereof; a means for locking the spindle to the workhead housing; a longitudinal tool slide table carried on the base for movement parallel to the spindle axis; a means for moving the longitudinal tool slide table; a tool index table carried on the longitudinal tool slide table for supporting a plurality of machining stations; a means for rotatably indexing the tool index table about the axis thereof a plurality of machining stations mounted on the tool index table, each of the stations having a cutting tool for machining a workpiece held in the workholder;
and a means for controlling the motions of the workholder and cutting tools of the machining stations.

The machine as recited in Claim 1 wherein each of the machining stations, during the use thereof, is demountable and separately mounted on the base for engagement of their respective cutting tools with the workpiece.

The machine as recited in Claim 1 wherein the machining stations include a spherical turning station and a spherical grinding station.

The machine as recited in Claim 1 wherein the machining stations include a ball groove milling station and a ball groove grinding station.

The machine as recited in Claim 1 wherein the machining stations include a spherical turning station and a ball groove milling station.

The machine as recited in Claim 1 wherein the machining stations include a spherical grinding station and a ball groove grinding station.

The machine as recited in Claim 1 wherein the machining stations include a spherical turning station, a spherical grinding station, a ball groove milling station and a ball groove grinding station.

The machine as recited in Claim 1 wherein means are provided in the workholder for attaching a workpiece to the spindle and for locating the workpiece in the direction of the spindle axis and angularly about said axis.

The machine as recited in Claim 1 wherein the workholder for attaching the workpiece to the spindle is adapted to hold corresponding outer race, inner race and ball cage members of a universal joint assembly.

The machine as recited in Claim 9 wherein the workholder for holding the corresponding outer race, inner race and ball cage members of a universal joint assembly locates said members such that the centers of spherical curvature of said members are coincident and the centers of the ball groove meridians of said members are coincident when the corresponding members are held in the workholder.

The machine as recited in Claim 1 further comprising:
a tool cross slide table mounted on the longitudinal tool slide table for supporting and moving the tool index table perpendicular to the workhead spindle; and a means for moving the tool cross slide table.

The machine as recited in Claim 1 further comprising:
a work slide table mounted on the base for supporting and moving the workhead parallel to the spindle axis; and a means for moving the work slide table.

A machine for making universal joints, of the type wherein multiple machining operations are performed on corresponding members of a universal joint, held in a common workhead and revolved about common axes conforming to the universal joint comprising: a base; a work swivel table mounted for rotation about an axis on the base; a means for swiveling said swivel table about said axis; a work slide table mounted on the swivel table for movement perpendicular to the swivel axis of the underlying table; a means for moving the work slide table; a workhead mounted on the work slide table, said workhead having a housing, a spindle mounted for rotation in the housing, the axis of the spindle being perpendicular to and intersecting the axis of the swivel table and a workholder attached to one end of the spindle for holding and moving a workpiece with the same motion as the spindle; a means for rotating the spindle about the axis thereof; a means for angularly indexing the workholder about the spindle axis; a means for locking the spindle to the housing; a longitudinal tool side table mounted on the base for movement in a direction parallel to the movement of the work slide table; a means for moving the longitudinal tool slide table; a tool cross slide table mounted on the longitudinal slide table for movement in a direction perpendicular to the longitudinal slide table; a means for moving the cross slide table; a tool index table rotatably mounted on the cross slide table, the axis thereof being disposed in a parallel and co-planar relationship to the axis of the work swivel table; a means for rotating the tool index table about the axis thereof; a plurality of machining stations, including a spherical turning station, a spherical grinding station, a ball groove milling station and a ball groove grinding station, mounted on the tool index table, each of said stations having a cutting tool thereon; and a means for controlling the motions of the workholder and machining stations of the machine.

In a machine for making universal joints, the combination of a base; a common workhead mounted on the base, said workhead having a workholder for holding and locating corresponding outer race, inner race and ball cage members of a universal joint assembly such that the centers of spherical curvature of said members are coincidentand the centers of the ball groove meridians of said members are coincident during the machining thereof; a means for rotating the workholder about a first axis through said coincident centers of spherical curvature during machining of the universal joint members; a means for indexing the spindle about the axis thereof; a means for locking the spindle to the workhead housing; a means for swiveling the workholder about a second axis through the centers of spherical curvature and perpendicular to the first axis; a means for swiveling the workholder through said coincident centers of the ball groove meridians, perpendicular to and intersecting the first axis; and a cutting tool means for machining the surfaces of spherical curvature and ball grooves of said corresponding joint members.

The machine for making universal joints as recited in Claim 14 wherein the means for machining the surfaces of spherical curvature and ball grooves in the members of the universal joint assembly comprises: a rotary index table mounted on the base opposite the workhead, the axis of the index table being disposed parallel and co-planar with the axis about which said joint members swivel during the machining thereof; a plurality of machining stations mounted at fixed locations on the rotary index table; means for indexing the rotary table for bringing each of the machining stations into position to engage their respective cutting tools with the workpiece; means for advancing a machining station in the direction of the workpiece after said station is brought into position by indexing the rotary table, to engage the cutting tool of said station with the workpiece; and means for controlling the motions of the workpiece and said machining stations.

A machine for making universal joints wherein multiple machining operations are performed on corresponding members of a universal joint, held in a common workhead and revolved about common axes conforming to the universal joint comprising: a base; a workhead rotatably carried on the base, said workhead having a housing, a spindle rotatably mounted in the housing, the axis of said spindle being in perpendicular and intersecting relationship to the workhead axis, and a workholder attached to one end of the spindle for holding corresponding members of a universal joint and moving the members with the same motion as the spindle such that the members revolve about axes conforming to the universal joint, said workholder having holding means for clamping the corresponding members of the universal joint to the workhead and for positioning said members in axial and radial directions with respect to the workhead spindle axis; a means for swiveling the workhead about the axis thereof; a means for revolving the spindle about the axis thereof; a longitudinal tool slide table carried on the base for movement parallel to the spindle axis; a means for moving the longitudinal tool slide table; a tool index table carried on the longitudinal tool slide table for supporting a plurality of machining stations; a means for rotatably indexing the tool index table about the axis thereof; a plurality of machining stations mounted on the tool index table, each of the stations having a cutting tool for machining a workpiece held in the workholder;
and a means for controlling the motions of the workholder and cutting tools of the machining stations.

A method for manufacturing universal joints of the type employing conjugate members having close fitting conform-ing surfaces comprising mounting each of the conjugate members in a common workhead during the machining thereof, imparting the same relative motions between the conjugate members and cutting tools as exist during the actual service of the members, engaging the cutting tools with the members and generating the close fitting conforming surfaces of the members by the cutting actions of the tools.

18. A method for manufacturing universal joints of the type employing conjugate members having close fitting conforming surfaces comprising:
(a) mounting a workpiece for machining one member of a universal joint assembly in a workhead, (b) swiveling the workpiece about an axis;
(c) engaging a machining tool with the swiveling workpiece in a manner such that a curved surface having a center of curvature on said axis is generated by the cutting action of said tool;
(d) disengaging the tool from the workpiece (e) de-mounting the workpiece from the workhead, (f) mounting a second workpiece for machining a conjugate member of the universal joint assembly in the same workhead in a manner such that the center of curvature of a curved surface to be machined in said second workpiece is coincident with the center of curvature of the first workpiece during the machining thereof;
(g) swiveling the second workpiece about the same axis as the first workpiece;
(h) engaging a machining tool with the swiveling second workpiece in a manner such that a curved surface, which is close fitting and conforming to a surface of a mating member of the universal joint assembly, is generated by the machining action of said tool;
(i) disengaging the tool from the second workpiece;
and (j) de-mounting the second workpiece from the common workhead.

19. The method of manufacturing universal joints recited in claim 18 wherein the tools for generating the close fitting and conforming spherical surfaces are turning tools.

20. The method of manufacturing universal joints recited in claim 18 wherein the tools for generating the close fitting and conforming spherical surfaces are grinding tools.

21. The method of manufacturing universal joints recited in claim 18 wherein the tools for generating the close fitting and conforming spherical surfaces are milling tools.

22. The method of manufacturing universal joints recited in claim 18 further comprising the step of indexing said first workpiece about a second axis which is in perpendicular and intersecting relationship to the first said axis after said workpiece is mounted in the common workhead and the step of indexing said second workpiece about the same axis after said second workpiece is mounted in said workhead.

23. The method of manufacturing universal joints recited in claim 18 wherein said first and second workpieces are rotated about a second axis which is in perpendicular and intersecting relationship to the first said axis during the same time said workpieces are swiveled about said first axis.

24. A method for manufacturing universal joints of the type employing conjugate members having close fitting conforming surfaces comprising:
(a) mounting a workpiece for machining a joint member in a common workhead;
(b) revolving the workpiece about an axis;
(c) swiveling the rotating workpiece about a second axis which is in perpendicular and intersecting relationship to the first said axis;
(d) engaging a machining tool with the revolving and swiveling workpiece in a manner such that a spherical surface, having a center of curvature at the intersection of the first and second axes, is generated by the cutting action of said tool;
(e) disengaging the tool from the workpiece;
(f) de-mounting the workpiece from the common workhead;
(g) mounting a second workpiece for machining a conjugate joint member of the universal joint in the common workhead in a manner such that the center of curvature of a close fitting and conforming spherical surface to be machined in said second workpiece is coincident with the position of the center of curvature of the first workpiece during the machining thereof;

(h) revolving the second workpiece about the same axis of revolution as the first workpiece:

(i) swiveling the rotating second workpiece about the same swivel axis as the first workpiece;
(j) engaging a machining tool with the revolving and swiveling second workpiece in a manner such that a spherical surface, having a center of curvature at the intersection of the first and second axes, is generated by the machining action of said tool which is close fitting and conforms to the generated spherical surface of the first workpiece;
(k) disengaging the spherical turning tool from the second workpiece; and (l) de-mounting the second workpiece from the common workhead.

25. A method for manufacturing universal joints of the type employing conjugate members having close fitting conforming surfaces comprising:
(a) mounting a workpiece for machining a member of a universal joint in a common workhead (b) simultaneously revolving the workpiece about a first axis and swiveling the workpiece about a second axis which is in perpendicular and intersecting relationship with said first axis;
(c) engaging a turning tool with the revolving and swiveling workpiece in a manner such that an unfinished spherical surface, having a center of curvature at the intersection of the first and second axes, is generated by the cutting action of said tool;

(d) disengaging the turning tool from the workpiece;
(e) engaging a grinding tool with the revolving and swiveling workpiece in a manner such that a finished spherical surface, having a center of curvature at the intersection of the first and second axes, is generated by the grinding action of said tool;
(f) de-mounting the workpiece from the common workhead;
(g) mounting a second workpiece for machining a conjugate joint member of the universal joint assembly in the common workhead in a manner such that the center of curvature of a spherical surface to be machined in said second workpiece is coincident with the position of the center of curvature of the first workpiece during the machining thereof;
(h) simultaneously revolving the second workpiece about the same axis as the first workpiece and swiveling the second workpiece about the same axis as the first workpiece which is in perpendicular and intersecting relationship with said first axis;
(i) engaging a turning tool with the revolving and swiveling second workpiece in a manner such that an unfinished spherical surface, having a center of curvature which is coincident with the center of curvature of the spherical surface of the first workpiece during the machining thereof, is generated by the machining action of said tool;
(j) disengaging the turning tool from the workpiece;
(k) engaging a grinding tool with the revolving and swiveling second workpiece in a manner such that a finished spherical surface is generated by the grinding action of said tool which is close fitting and conforms to the finished spherical surface of the first workpiece;
(l) disengaging the spherical turning tool from the second workpiece; and (m) de-mounting the second workpiece from the common workhead.

26. A method for manufacturing universal joints of the type employing conjugate members having close fitting conforming surfaces comprising:
(a) mounting a workpiece for machining a member of a universal joint in a common workhead;
(b) indexing the workpiece about a first axis;
(c) swiveling the workpiece about a second axis which is in perpendicular and intersecting relationship with said first axis;
(d) engaging a milling tool with the swiveling workpiece in a manner such that an unfinished curved surface, having a center of curvature at the intersection of the first and second axes, is generated by the milling action of said tool;
(e) disengaging the milling tool from the workpiece;
(f) engaging a grinding tool with the swiveling workpiece in a manner such that a finished curved surface, having a center of curvature at the intersection of the first and second axes, is generated by the grinding action of said tool;

(g) de-mounting the workpiece from the common workhead;
(h) mounting a second workpiece for machining a conjugate joint member of the universal joint assembly in the common workhead in a manner such that the center of curvature of a curved surface to be machined in said second workpiece is coincident with the position of the center of curvature of the first workpiece during the machining thereof;
(i) indexing the second workpiece about the same axis as the first workpiece;
(j) swiveling the second workpiece about the same axis as the first workpiece which is in perpendicular and intersecting relationship with said first axis;
(k) engaging a milling tool with the swiveling second workpiece in a manner such that an unfinished curved surface, having a center of curvature which is coincident with the center of curvature of the spherical surface of the first workpiece during the machining thereof, is generated by the milling action of said tool;
(l) disengaging the milling tool from the workpiece;
(m) engaging a grinding tool with the swiveling second workpiece in a manner such that a finished spherical surface is generated by the grinding action of said tool which is close fitting and conforms to the curved surface of another member of the universal joint;
(n) disengaging the grinding tool from the second workpiece; and (o) de-mounting the second workpiece from the common workhead.

27. A method for manufacturing universal joints of the type employing conjugate members having close fitting conforming surfaces comprising:
(a) mounting a workpiece for machining a member of a universal joint in a common workhead;
(b) simultaneously revolving the workpiece about a first axis and swiveling the workpiece about a second axis which is in perpendicular and intersecting relationship with said first axis;

(c) engaging a turning tool with the revolving and swiveling workpiece in a manner such that an unfinished spherical surface, having a center of curvature at the intersection of the first and second axes, is generated by the cutting action of said tool;
(d) disengaging the turning tool from the workpiece;
(e) engaging a grinding tool with the revolving and swiveling workpiece in a manner such that a finished spherical surface, having a center of curvature at the intersection of the first and second axes, is generated by the grinding action of said tool;
(f) indexing the workpiece about the first axis;
(g) swiveling the workpiece about the second axis;
(h) engaging a milling tool with the swiveling workpiece in a manner such that an unfinished ball race, having a center of curvature at the intersection of the first and second axes, is generated by the milling action of said tool;
(i) disengaging the milling tool from the workpiece;
(j) engaging a grinding tool with the swiveling workpiece in a manner such that a finished ball race, having a center of curvature at the intersection of the first and second axes, is generated by the cutting action of said tool; and (k) de-mounting the workpiece from the common workhead.