claim as our invention: 1. The method of cuttin(y a (year or wheel which consists in moving W to@'I in ,t curved 95 path in a plane substantially tangent to the pitch surf ace of the gear t@ be produced to shape the tootb, imparting a continuous indexing movement to the blank, and simultaneously rolling the blank on its pitch sur- IOQ face to generate the tooth. 2. The method of cutting a gear or wheel which consists in moving a tool in a curved path in a plane substantially tangent to.the pitell surface of the -ear to be ptoduced to 105 shape the tooth, impwrting a continuous in- dexing movement to the blank, and simultaneously producing a relative rolling. motion between the blank and to6l to generate the tooth. 110 3. The method of cutting a gear or wheel which consists in moving a tool in a curved path in a plane substantially tangent to the pitch surface of the gear to be produced to shape the tooth, imparting-a generatin(-t mo- 115 tion to the blank and the tool to generate the tooth, and producing a continuous indexing movement of the- blank. 4. The metliod of cutting a gear or wheel which consists in moving a tool in a curved 120 path in a plane substantially tangent to the h surface of the gear to be produced to pite shape the tooth, and simultaneously producing a combined rolling and indexino@, movement of the blank whereby each tooth is 125 generated and the blank is indexed between successive operations of the tool. 5. The method of cutting a gear or wheel

Wllicli consists in moviiicy a pltirality of tools in aetii-N,e(I patli in a I)Iane stibstintially tangent to the I)iteli stirface of the cear to be pro(Iticed to slitpe the teetli, producin,r a relative rollin(r motion betiveen the blank and tlle tools to generite the teetli, and simttltaneoiisly imp@rtin(, a continuoiis indexiii(r movenient to the blank. 6. The nietliod of ciittin(, a @rear or wheel t-I eD 10 wliieli consists in niovin(r a I)Iurality of tools in a curved patli in a 1)1,ine substantially tangent to the I)iteli stirface of tlie oe-,ir to be prodiieed to shal)e tlio teetli,,prodricing a rollin,r niotion of the blank with relation to 15 the tools to generate the teeth, and simultaneously impartin,,r a continuous indexinmovement to the blank. 7. The method. of cuttin(, a -ear or wheel wliieh consists in moving a plurality of tools 20 in a curved path in a plane substantially tantrent to the pitch stirftee of the -ear to be produced to shape the teetli, pi-oducing a gencratin(r motion of the blank and tools wliile the el latter are cutting, and simulta25 neously imparting a continuous indexing movement to the blank. 8. The method of forming the side face of a curved gear tooth, which consists in causing a ' tool to describe a curved path 30 across the f ace of the blank, imparting a continuous indexing movement to the blank, and 'simultaneously producing relative rollin(r motion bet'ween the blank and tool alon,-, t, the plane of the curved path of movement 35 of the tool. 9. The method of forming the side f ace of curved trear tooth, which consists in causin- a tool to describe an arcuate path across t, the f ace of the blank in a plane substantially 40 tan(rent to the pitch surfaoe of the gear to be produced imparting a continuous indexin- movement to the blank and simultaneou@,lv producing relative rolling motion betwe@n the blank and tool along a plane 45 tangent to the pitch line of the blank and normal to the tool axis. I 10. The method of form'ing the side face of a curved gear tooth, which consists in cau@ing a tool to describe a circular path 50 across the face of a blank, imparting a continucous indexing movement to the blank in a plane substantially tanoent to the pitch '@roduced, and sisurface of the gear to be multaneously producing relative rolling mo55 tion between the blank and tool along the plane of the curved path of movement of the tool. ii. The method of forming the side face of a curved gear tooth, which consists in 60 causing a tool to describe a circular path around an axis and across the face of the blank, imparting a co'ntinuous indexing m6vement to the blank, and simultaneously producing relative rolling motion between the blank and tool alon- a plane tangent to 65 the pitcli line of the blank and normll to the tool axis. 12. The metliod of cuttin(y a Year or wheel wliieli consists in movin,, a tool in a circulir path in i pline stibstantially tangent to 70 the pitcli stirface of the gear to be produced to sliape the tootli, impartin(r ,t continuous indexinr movement to the blank and simultn tineously rollin(r the blank on its pitch surface to 'ed.etate tlie' tooth. 75 1 13. The metliod of cutting a gear or wheel wliieh consists in moving a tool in a circular patli in a plane substantially tangent to the piteli surface of the -ear to be pi oduced to shape the tooth, prodticing a relative rolling 80 m6tion between the blank and the tool to generat @e the tooth, and imparting a continuous indexing movement to the blank. i4. The Tethod of cutting a gear or wheel which consists in moving a tool in a eir- 55 etilar path in a plane substantially tangent to the piteli surface of the gear to be produced to shape the tooth, and simultaneously impartin g to the blank a combined indexing moveme nt, and rolling movement with ref- go erence to the tool. 15. The method of cutting a gear or wheel wliieh consists in moving a plurality of tools in a circular path in a plane substantially tangent to the pitch surface of the gear to 95 be prodticed to shape tlle teeth, producing a relative rollin- motion between the blank t!l and the tools to generate the teeth, and simultan eously impartirig a continuous indexing movement to the blank. 100 16. The metliod of cutting a -ear or wheel whicli consists in movih- a plu@ality of tools in a circular path in at'plane substantially tan(rent to the pitch surfaee of the gear to be @roduced to shape the teeth, prodiicing lo5 a generating motion of the blank and the toois to generate the teefli, and simultaneously impartintr a continuous indexing movement to the blaiik. 17. The method of cutting a bevel gear lie whicli consists in moving a tool iR a circular path in a plane substantially tangent to the piteli stirface of the gear to be produced to shape the tootli, producing a generating motion of the blank and the tool to generate 115 the tooth, and imparting. a continuous indexinmovement to the blank. t 18. The method of cutting a bevel (rear whicli consists in moving a tool in a circular path in a plane substantially tangent to 120 the pitch stirface of the gear to be produce(i to sbape the tootli, and simtiltaneoiisly imparting to the blank a combined indexinmovement and rollino- movement with refereiiee to the tool, whereby eacli tootli is 125 generated and tl)e blank is indexed between -successin-e ol)erations of the tool. 19. In a machine for (-tittin- cui,N-ed teetli,

1,349,951 the combination with a blank carrier, of a plurality of tools movable in a curved path across the face of the blank, means for produciiig a relative rolling motion between the blank carrier and tools to generate the sides of the teeth, and means for imparting' a- continuous indexing movei4ent to the blank. 20. In a machine for cutting curved teeth, 10 the combination with a blank carrier, Qf a ..plurality, of. tools movable in a curved path across the face of the blank, the cutting edges of adjacent tools being arranged to cut on relatively opposite portions of th@ i5 teeth of the blank, and means for producing a continuous indexing mqvement of the blank. 21. In a machine for cuttine teeth, the combination with a blank carri@r, of a'plu20 rality of tools movable in a curve4 path across the face of the blank the adjacent tools having their cutting edges arranged to engage relatively opposite portions of the teeth of the blank, means for imparting a 25 relative rolling motion to the blank carrier and tools to generate the sides of the teeth and means for simultaneously producing a' continuous indexing movement of the blank. @2. In a machine for cutting curved teeth, so the combination with a blank carrier, of a plurality of tools movable in,a curved path across the face of the blank, means for.imparting a rolling motion to the blank carrier to generate the sides of the teeth, and 35 means for impartiiag a continuous indexing movement to the blank carrier. 23. In a machine for cuttino, curved teeth, the combination, with a blank carrier, of a plurality of tools movable.in a curved path 40 across the face of the blank, means for imparting a relative rolling motion to the - blank carrier and tools to generate the sides of the teeth, and means for producing a' continuous indexing movement of the blank 45 carri(!r. 24. In a machine for etittino, curved teeth, the combination with a blank carrier, of a plurality of tools movable in a curved path ac@oss the face of the blank, the cuttihg 50 edges of adjacent tools being arranoed to cut on relatively opposite portions'@f the teetli of the blank, means tor. producing a rolliner motion of the blank carrier to generate the sides of the teeth, and means for im55 parting a continuous indexing movement to the blank. 25. In a mtichine for cutting curved teeth, the combination with a, blank carrier, of a 1)liii@.,ility of tools movable in a ciirveld patli 6o across the face of the blank, the cutting ed-es of adjacent tools being arranged to cut on i-clatii,ely opposite portions of the blank, means for producing a generating motioii of the blank carrier and tools to generate the sides of the teeth, ajid means for 65 impairting a continuous indexing movement to the blank carrier. 26. In a machine for cutting curved teeth, the combination with a blank carrier, of a rotary tool head, a plurality of tools on the 70 head having their cutting edges substantially the same distalace from the center and movable in a curved path in a plane sub@ stantially .,tangent to, the,, p.itch surface of the gear to be produced, and means for 75 producing a continuous indexing movement of the blahk co6rdinated with the rotati6n of the tool head so as to cause the tools to engage with different teeth on the blank during a single revolution of the head. 50 27. In a machine for cutting curved teeth, the combination with a blank carrier, of a rotary tool head, a plur'ality of tools carried on the tool head and movable @in a curved,path across the face. of the blank, BE, the tools having engagement with different teeth 6n the blank during a single revolution of the tool head, means for--pioducing a relative roring motion between the blank carrier and tool head to enerate the sides of go the teeth, and means f(or imparting a'continuous indexing movement to the blank carrier. 28.. In a machine for cuiting curved teeth, the combinatio.n with a blank carrier, of a 95 rotary tool head, a plurality of tool@ carried on the tool. head and movable in a curved path across the face of the blaiik, means for producing a roning: motion of the blank carrier to generate tyie sides of the teeth, and loo means for imparting a continuous indexing movement to the blank carrier. 29. In a machine for cutting curved teeth, the combination with a blank eirrier, of a rotary tool head, a plurality of tools car- loa ried on the tool head and movable in a cu.&ed path across the face of the blank, the tools having engagement with different teeth on the blank during a single revolu7, tion of the tool head, means ' for produ 110 tool head ciZ a genetatinlr motion of the a I blank eirri@r to generate the sides of the teeth, and means ior imparting a continuous indexing movement to the blank carrier. 30. In a machine for cutting curved teeth, 115 the combination with a tool moving continuously in @ circular path, of a- blank carrier having a continuous indexing movement, and means for producing a relative rolling mbtion between the blank carrier and 120 tool. 31. In a machine for cutting curved teeth, the combination with a tool moving contintiously in a circular p h, of a blank carat rier havino-, a continuous indexin- iiaove- 125 ment, and means for impartin to iKe blank .9

1,349,951 7 carrier in additional movement of rolling with relation to the tool to generate the sides of the teeth. 32. In a machine for cutting curved teeth, the combination with a tool moving continuously in a circular patli, of a blank carrier havino- a c6ntinuous inde movexlno' ment, . mea@s for imparting a rolling move ment to the tool, and means for producing 10 an additional rolling movement of the blank carrier -",ith relation to the tool to generate the sides of the teeth. 33. In a machine for cutting curved teeth, the combination ivith a continuously rotat15 ing blank carrier, of a rotary tool head and a series of tools arranged concentrically of the head in spaced relation to each other and extending in a direction perpendicular to the face of the head so as to cut a surface sub20 stantially perpendicular to the axis of the tool head, the adjacent tools having their cutting edoes oppositely arranged for engagement with different portions of. the blank as the latter is rotated. 25 34. In a machine for cutting curved te6th, the combination with a contiiiuously rotating blaiik carrier, of a rotary-tool head and @ series of tools arranged on the tool head in spaced relation to each other, the alterSo liate tools 1-iaving their cutting edges extending in opposite directions and engaging witli different portions of the blank during a revoltition of the tool head. 35. In a machine for cutting curved teeth, 36 the combination with a rotary tool liead of a series of tools arranged concentrically of the head in spaced relation to each other and extending in a direction perpendicular t.o the face of the head so as to cut .t surface 40 stibstantially perpendicular to the axis of the liea(l, the ad acent to s having their cuttin,- edges ol)l)ositely dis sed. i36. Iii a macliine for cutt ng curved teeth, the eonibination with a rotary tool head, 45 of i sei,ies of tools arrangE@d,6n the liead in sl).t(-e(i i-elit'oii to each other and extending ill :1 (iii-ectioti perpen(licular to the face of the lie.,,id so (is to ciit a surface stibstantially I)ei-I)eii(ii(@iilar to the axis of the head, the 5o tools litn-iiig their cutting edges 01)])Ositelv (lisl)osed. 37. Tiie niethod of (reiierating spiral ben-el gears,- compi-isin(, trie rd.ovement of a sei,ies of generating tools throuoli tlle same 55 patli in a plane stibstintially tan-ent to tlie, I)it(-Ii surface of the gear to be produced tr,insi-ersely of the gear blank and through ,in endless orbit, ind simultaneously im]),Il@ting to sai(i gear blank ,i combined roll60 ing and rotational movenient by which sticcessil,-e tools generate successive teeth. 38. The metliod of cutting IODgitLidinally curved teetli in a bevel gear blank %Nbicit consists in rot,,iting a pliirality of ciittin(" tools, at a uniform radial distance from a 65 common axis, iinparting to the blank a continuous rotary indexing movement about its qxis, and simultaneously effecting a relative rolling ae-nerating movement between the tools and blank over the pitch cone Of 70 the latter. 39. The method of cutting loiigitudinaliy curved teeth in a bevel gear blank which consists iii imparting to- the blank a contintioiis rotary indexing movement about its 75 axis, rotating a pli-irality of tools of substaritially uniform radius to represent an intermes hing gear, and simultaneously effecting a @elative rolling generating niovement between the pitch cone of the blank 80 and. the pitch surface of the gear represented by said tools. 40. The method of cutting longitudinally curved teeth in a bevel gear blank which consists in imparting to the blank a continu- Sr, ous rotary indexin(y mon,ement about its axis, rotating a cutter ga%,in@ a plurality of cuttiny. tools in continuous intermesliino, relati(@ with a plurality of teeth cut in th@ blank during each rotation of the cutter, and sigo mult,,tneously effecting a relative rolling moveme nt between the tools and blank over the pitch cone of the latter to generate the tooth profiles. 41. A machine for cutting longitudinally 95 curved teeth in a bevel gear blank comprising a cai-rier for the blank liaving a continuous rotary indexi ng movement, a pltii-ality of cutting tools rotatable about a common axis at substantially equal distances 100 tberefro m and ,irranged to co6perate with said carrier for producing longitudinally curved teeth on said blank, and actuating means for effecting a @relative folling movement between said tools and blank on the iob pitch cone of the lattet, to feed the blank and tools and -enerate the teetli profiles. 42. A mach@ine for (-tittin(r Ion(-itudinally t, el curved teeth in it bei-el ,k@.ir blank comprising t. carrier for the blank liaving a con- lio tinuotis rotnrv indexing movement, a rotary eittter li',i,%-ing a pliirility of tools arranged to eobperaie with the carrier for I)rodiiclnlu loiigitiidinally'ctirved teetli iii a bevel gear blinli:, icttiating. means for i@otatino, 115 the tools in intermesliiiig relation witli a I)Iurality of teeth cut in the blank diiring each rotation of the ciitter for cutting all of the teetli at the same time, and me,,Iiis for effecting , (i simtilt,(ineoiis relative rollin(,, 120 moveme nt of the cirrier and tools over thde piteli cone of the blank to fee(I tlle blank and tools and -enerate the tooth profiles. 43. A macliine for ctitting longittidinally etirn-ed teet.1i ip a bevel geii, bl-,Ink eompris- 125 in(, i cari,ler for the blank liaving a con-

tinuous rotary indexing movement about the blank axis, a rotary cutter having a plurality of tools arranged for co6peration with the carrier for producing longitudinally curved teeth in the bevel gear blank, actuatin,g nic@ans for rotating the tools in continuous intermeshing relation with the teeth cut in the blank whereby said tools enga-ge a plurality of blank teeth during each rotaio tion. of the cutter a support for said carrier, a support for said cutter, and meads for 1,349,951 moving one of said supports during the cutting op@ration to e:ffect a relative rolling movement of the carrier and tools over the pitch cone of the blaiak to feed the blank and tools and generate the tooth profiles. JAMES E. GLEASON. ARTHUR L. STEWART. Witnesses: R. E. STONEBRAKERI RussELL B. GRIFF.ITH.

UNITED STATES PATENT OFFICE. JAMES E. GLEASON AND ARTHUR L. STEWART, OF ROCHESTER, NEW YORK, ASSIGNOP.S TO GLEASON WORKS, OF ROCHESTF@R, NEW YORK, A QAPEQIILATION OF NEW YORK. HEIgo QVDUEE METHOD OF AND XACHXNE FOR CUTTING GEARS OR WHEELS. 1,349,951. Specification of Letters Patent. I'ateiited Atig. 17, 1920. Application filed December 26, 1914. Serial No. 879,026. lo all, -tt,ho?it it may conce?,,n.l Be'it known that We,, JA3i.Es E. GLEASON and ARTHUR L. STEWART, both of Rocliester in the county of Monroe and State of New York, liave invented certain new and useful Impro'k,ements in Methods of and Machines for Ctitting (')rears or Wheels; and we do liereby declare the following to be a full, clear, and exact description of the same, refio erence being liad to the accompanyin- draivings, forming a part of this speci@eicion an(] to the reference ntimerals marked thereon. The invention pertains generally to a metliod of and machines for cutting teeth or 15 blades on ge,.tt-s, wheels, or similar bodies, and among the various possible applications, it is desirned more particularly with refer@ ence to the production of ciirved, -eneraied teeth on bevel -ears, the chief purpose be20 ing to afford an improved method an([ mechanism for producing theoretically correct etirved gear teeth speedily and with accilracy. The method consists, broadly stated, in movin(y a cutt.,ng tool in a ciirved path in 25 a plane @tibstantially tangent to the pitch siirface of the gear to be prodticed to shape the tooth imparting a continuous indexin(y zn movement or rotation to the blank, and simtiltaneotisly causing a relative rollin,(,, So mon,@ment between the blank and tool durin(r'the cutting operation to -enerate the tootli. To these and other ends the invention consist-, in certain improvements and combinations of parts all as will be herein35 after mbre fully described, the novel features beina pointed out-in the claims at the end of the specification. In the (irawings: Figii@e I is a side ele@atioil of a machine, 40 illtistratiiig the invention in one of its possible embodiments, the blank and tool head bein,,, out of cutting relation; Fig. 2 is a @lan view with pai-ts in seeti the blank bein partially fed in to the oll' .9 45 ftill cutting depth; Fig. 3 is an,@n'd elevation, looking toward the rial'it of Fig. 1; Fi-. 4 is a h6rizontal sectional view on the 117ne 4'a--4a of Fig. 3' 5o Fig. 5 is a, vertical sectional view on the line 54-51,1 of F,ig. 3; Fig . 6 is a plan view of the reversina meel lanism sho-,i,n generally in Fig. 1; t@ Fi . 7 is. a sectional view on the line ig 7a'ta of Fil-. 6 with parts appearin- in 55 elev ation; F ig. 8 is a vertical sectional view on the line 8a -8a of I"ig. 1, partially in elevation; Fig . 9 is a plan view of a portion of the gear ing which controls the movenient of the 60 blan k carrier, showing the arrangement whe reby the combined indexing and rolling, or generatin,-,, movement of the blank carrier is obtaiiied; F ig. 10 is an end elevation, looking to6 5 ward the left of Figs. 1 and 2; F ig. 11 is a vertical sectional view on the line Ila--Jla of Fig. 1; F ig. 12 is a plan view of the table on whic h the blank carrier is mounted, parts 70 abov @ the table being removed; F ig. 13 is a sectional view on line 13a-13a of Fig. 1; F ig. 14 is a sectional view on the line 14a @-141, of Fig. 12, showing the aearin- 75 wliie h controls the movement of the blink' carri er table; F ig. 15 is a sectional view on the line 1,ia-- 15a of Fig. 6; F ig. 16 is a sectional view on the line 8 0 16"- 16" of Fig. 1; F ig. 17 is a diaorammatic view showin,, the relative positizn of the tool head an.@d blan k, m,hen cutting a bevel aear; r 4ig. 18 is a similar view illustrating the 8 5 arra ngement of tools' and relative position of I)arts for ciitting a bevel pinion; F ig. 19 is a partial elevation of a tool liead sliowin,- the position of the ctittin(, tools thereori; 90 l @'ig. 20 is a perspective view, in part, of one of the tools; F i-. 21 is a plan view of a tool 1-iead, %-,,ith a modified arrangement of tools, -%vhereby t etit is made on both sides of each tooth dur- 95 ing one complete revolution of the blatik F ig. 22 is a deta.il vienv shoi@iiig the cutting relation of the tools to 2a blank, with the arrangement of tools sboivn iii r4l(,r. '-)l; Fir. 23 is a side elevation of a pprtion of lothe tool liead, illustratin(r the arran-ement of one of the tools;

Fig. 24 is a sectional view on the line 24-24a of Fig. 23, and Fig. 25 is a diagrammatic showinr of the manner in which the cutting tools coi@perate with the teetb of a blank, ivith the arrangement of tools illustrated in Fig. 21. . Similar reference characters in the several figures indicate the same parts. The embodiment of the invention herein io shown and described is intended merely for the purpose of illtistration, and while designed for producing -,i,hat ig known in the art as a curi,ed gear tooth, it is to be understood that the invention is like-,vise adapted i5 for producing curved cuts on wlieels or similar bodies, to form'blades, teetli or the like, and in the following description and claims the term "tootli" is employed ,is comprehending a blade or similar portion pro2o duced on the periphery or otber f ace of a wheel by means of cuts or slots formed on opposite sides o4 the toofth. Wliere the terms "generating motion" or "rolling motion@ )I are employed, they are tised synon25 Ymouslv, and together ivitli "-enerated tooth" refer to the relative movement between the blank and tool, corresi)onding to the moveme'nt of a gear rolling upon a rack, and resulting in the formation, or genera30 tion, as it is called, of a theoretically correct profile or side of the tooth. The term "indexing motion'@ refers to the movement of the blank, wliereby different teetli are brought successively into position for a tool 35 to 6ngage, the blank of the present invention having a continuing indexing motion after the manner of a hobbing machine. The invention contemplates the production of "curved" teeth, and this expression refers 40 to the shape of a tootli longitlidinally, or from end to end, and is intended to define or (,omprehend the form or forms of teeth which are variously known in the art as curved, spiral and cireiilar. 45 The present machine may be described in its broad as@ect as including a rotary tool head on which are mounted a rie of tools or cutters arranged in space relation to each other movable in a curved path in.a 5o plane substantially tanght to the pitch surface,of the gear or wheel, the disposition of the tools being such that when the tool head is continuously rotated in engagement with a continuously rotating blank, the cutters 55 successively enoage different portions of the blank, each operating to make, a single cut on the side of a tooth until all the teeth are completed. This result may be obtained by arranging the tools so as to engage cor6o responding sides of every other tooth, or by having the tools ai-ranged in pairs to enga e the adjacent sides (>f adjacent teeth, t@e first mentioned arrangen-xent requiring two revolutions of the blank to make one cut on 1,349,951 oiie side of each tooth, Nvliile the latter ar- 65 rangement re(litires one revolution of the blank to make one cut on both sides of each tootli all of ivhich inill be fullv explained in the folloi-,7iii(f description. In ad(lition to the iadexing @moi,ement of the blank car- 70 rier, the latter is also controlle(I in sucli a manner as to liave imparted thereto a rollin.(r mon,ement, or generating movemeiit, Nvith relation to the tool in operation at any I)articular momeiit, foi- the plirpose of gen- 75 erating or atitomatically prodticin- theoretically correct sides on the teeth, and this is accomplished by rollin(" both the tool head and the blank, the parts being ()'eared together, so that t@e rolling movement Of 80 the tool liead, which is mounted on an automatically oscillated @upport, is transinitted to the gear blank, this rolling motion of the tool head being added to or subtracted from the indexin(, mon,ement of the blank by 85 dilterential gearing, accordin(@ to whetlier the direction of roll is the same as, or contrary to, the indexin(r movement of the blank. In this class of work, it is customary to rough out the blanks, withotit fini@h- go ing the sides of the teeth, and to subseqtientl@ put them through a finishing machine, and the present apparatus may be utilized eith6r in the capacity of finishing a blank, in which the rouoh cuts have al- 95 ready been produced, or ir@making a com- pletect operation, that is -to say, entirely finishin(, the teeth of a blank which has not been preliminarily subjected to a roughing oitt operation. 100 In the present mechanism 1 designates the base on Nvhich is mounted a bed 2, the sup- - port for the tool head being arranged on the bed 2 for movement back and forth. To this end, the said bed includes ways 3 105 which itre engaged by tracks 4 carried by the cradle or tool head support 5- 6 is a standard, arranged for horizontal qdjiistment on the cradle 5, and provided Avith vertical guideways 7 on which is arranged 110 the housinz 8. Journaled in stiitable bearings on th@ housing 8, is . a spindle 9 which is adjustable longitudinally of the housing, and carries the tool head 10 fixed thereon. Also fixed on the spindle 9 is the internal 115 gear 11 by means of which the tool head is driven throulrh the following train of gear'ng. 12 des,,,gnates the main drive shaft of the machine havin(, fixed thereon aT pulley 13 to wblich power-may be applied. The 120 shaft 12 carri'es at its inner end a pinion 14, engaging a double pinion 15 fixed on the transverse shaft 16. The pinion la- drives the vertical shaft 17, provided at its lower end with a bevel gear 18 and slidably mount- 125 ed in bearings provided near its upper end for this purpo.%. The shaft 17 carries a bevel pinion 19 engaging a corresponding

1,349,951 ,-ear 20 on sliaft 21, the latter at I its opposite en(I a pinion 22. on 22 enga@res 1)inion 23 whicli is iix@elcli (P)Iilntihe sliaft 24, the last mpntioned sliaft carryin,r at its otiter end a pinion 25 eiigitging the intei-iial (-ear 11. 13y the means jiist descril)ed it will be seen th-,tt the tool head is coiitiniiously driven in one direction, and the means by wliieli the indexing motion 10 is imparted to the blank carrier and the generating motions to the blank carrier and tool. head ivill now be described. The blank, or (,,ear, is designated at 26, and is mounted on a blank carrier 27, the 15 lattei, bein- provided witli a worm ivheel 28 fixed tliereon and driven by a worm'29. 30 is a sliaft carrying tlie'%vorm 29 and ,Llso a bevel piiiion 31 which is. driven by tlle bevelpinion 32 arranged on shaft 33. The latter 20 carries a bevel gear 34 -%vhich is driven from the shaft 35, which in turn is operated froni sliafts 36 and 37 by means of the gearin-u shown in Fig. 8. The shaft 37 has fixea tllereon a bevel pinion 38 meshing ivith pin25 ions 39, carried by the sleeve 40 of a differential (yearino41. 42 is a shaft carrying the gear 43 wliick is driven by a Lyear 44 mouiited on a stub shaft which als@'carries a gear 45. The latter meshes with a gear 46 on so the shaft 47 which is driven f rom @haft 48 thr'ough bevel gears 49 and 50. The shaft 48 carries at its outer end a gear 51 wliieh meshes with a, gear 52, mounted on the reversible shaft 54, which is controlled by a 85 reversint mechanism that will be described hereina ter. The shaft 54 is driven from the shaft 55, carrying a gear 56, operated tlirough the idler gear 57 by th'e cear 58 t@ mounted on the main shaft 59. The shaft 40 59 is provided at one end -with a gear 60 wliich is engaged by a Lear 61 on stub shaft 62. The latter car@ies @ bevel pinion 63 engaged by a corresponding pinion on the drive shaft 12. 45 The oscillatory or -rolling movement of the tool head support or cradle is effected from the sbaft 48, which is alternately driven in opposite directions through the reversing mechanisffi already mentioned, 50 and to this end shaft 48 carries a bevel -ear 64, -,vliieh drives a, correspondinl, pinio@ 65 on a shaft 66. The last mentioi@ei shaft is inounted in suitable bearings beneath the cradle and is provided with a worm 67 hav55 in- engagement ivith a segmental worm gear 68 secured to the cradle. With this @rrangement it will be seen that a generating movement is imparted to the blank carrier throtigh the dilterential 41 in accord60 ance with the movements of the cradle which carries the tool head, and the means for "rting the indexing motion to the blanktwpill now be set forth.- For indexing, the blank is driven continuoiisly in one direction, and to this en(I th c 65 sliaft cirries a pinion 69 wliieli drives the sliaft 70 tlirou-11 pinion 71. The sliaft To in ttirn drives the spindle 72 bv means of pinioris 73 tnd 74, and moiinted on the spindle 72 is i (,,ear 75 mesliing witli aii idler 76 70 wliieli latter en-a(,es the gear ivlieel 77 fixed on the sleeve 40 of the diff erential r ,-Iearin(,,. The drive mechanism is so arranged that wlien the tool liead is rolling in the same directio n tli,,tt the blank travels, an increased 75 move ment is -iven to the blank tliroti(rh the t, el differe ntial meelianism, and when the tool liead is rolling in tlle opposite direction, or revers e to the indexing movement of the blank, sucli indexing movement is retarded, 80 and thus the blank, rotatin(r about its own axis,' is ,iven -,I, movemen't" which is the resiilta nt"or combin,,ttion of the indexing ind (yeneratiri- motions, and is so proportioned with i-elation to the rolling movement 85 of the tool liead that the respective tools -,ire severally brought into correct cutting relatio n with different portions of the blank wliile at the same time the side or profile of each tooth is generated, due to the constantly go changi ng relative position of each tool, resulting from the rolling or generating movement of the tool head. Aft er the tool head has rolled to the limit of its - movement in one direction it is iieces- 96 sary to reverse its direction of movement, tnd the present machine is designed with the idea of cutting the blank during the rollin ' (y moveme,,t of the tcrol head in both directio ns, although it may be desirable to 100 withdr aiv the blank from' cutting relation witli the tool head durin the reverse move9 ment of,the cradle. In order to effect such chang e of direction of Rlovement, the sliaft 55 c,,irries at one end a pinion 78 which en- 106 gages the idler 79, the latter meshin- with gear wheel 80 on worm shaft'81. 82 is a worm fixed on the worm sha,ft 81 and engaging the worrn gear 83 which is keyed to the spindle 84. 85 is a disk fixed on the 110 spindl e 84 and provided with a cam slot 86 which governs the movement of a lover 87, the latter being pivoted at 88 and movable first in one direction and then in the other by engagement with the cam slot 86. and 115 resulti ng in the alternate reversil of tlle shaft 48 in the manner in ivhich %vill nolv be descri bed. Loos ely mounted on shaft 54 is a pair of gears 89 and 90, the gear 89 bein(y driien 12( direc - tly from pinion 91 on shaft 00, whil6 gear 90 is driven through idler gear 92 from pinion 93 on shaft 55. The gears 89 and 90 are thus driven in opposite directions Ind Fidapt ed to be alternately locked to the shaft 125 54. To this end, the latter bas fixed tliereon a pawl carrier or collar 94 on %vhich are pivotal ly mounted locking pawls 95 and 96,

I)oth fixe(I on a pin 115, and arran,),ed for eng,,igement witli shoulders 97 and 98 on sleeve.s carried by ttie gears 89 and 90, and designated at 99 and 100. The locking pawls 95 and 96 are provided witli tail pieces or operating I)ortions 101 and 102 whi6h are engaged by t roller 103 carried on the lever 87, when the latter is moved into the path of one or the other of said pawls. The collo lar 94 also carries a spring actuated locking pin 104, arranged in a suitable housing and oj)erating on the tail piece 101 of pawl 95, so as to retain one or the other of the pawls in locked relation with the collar uiitil the 15 roller 103 is operated to engage the otlier 1)awl and thiis release the first mentioned one. The sleeves 99 and 100 are preferably prolvided with the inclined pro.jections 105 which aro adapted to ongtge the paivl and 20 carry them f tilly into tlleir released position, in case the roller .103 does not move them sufficiently for this purpose. The blank carrier is ,tdjustably mounted on a -tat)le 106, the latter being adapted for 25 switiging movemerit ,ibout the central axis 36, wlien ol)erating on a blank which has not previously been rk)uglied out, in order to feed the blank in so that the tools will cut to the full depth, or down to the root angle. The so machine may, with equal facility, be used in finishing blanks in which rough cuts have already been made on a roughing machine, and in this case, the table 106 is held in fixed positio . In order to effect tlle necessary n 35 swinging movement of the table 106, we a mechanism similar to what is =Yin co-pending application, Serial NO. 843,720, filed June 8, 1914, and.comprising generally a cam 107 mounted on the spindle 40 84 and engaging projection 108 on a swinging arm.116 adapted to move the table. The spindle 84 is driven at such a speed as to feed the blank toward the cutter slowly so that the tools will cut to the full depth by the 45 time the sides of the teeth are completed. In Figs. 17 to 19, inclusive, there is showii an arrangement in which alternat.e tools ha.ve their cutting edges extending in opposite directions, so that for each setting of the 50 blank, only every other tool will operate, the remaining tc)@ls bein(, inactive. In the arrangement shown in Fig. 17, for instance, the tools marked o will make a cut each time they pass through the blank, while 55 those marked y pass through the blank without cuttini. After t@e teeth are completej on one side, the blank is reset so as to permit the tools y to operate on the opposite sides of the teeth while the tools x are in60 active. A reverse arrangement of tools is shown in Fig-. 18 for cufiing a pinion. In Figs. 21 and 22 the tools are shown arranged in pai'rs, the tools of each pair passirig through a tooth space successively, and 1,349,951 operating on the adjacefit sides of adjacelit 65 teetli. Thiis the tools c and d will cut on the sides c' and d', while tools e and f, constitutin the next pair on the tool head, cut the Si ges e' and /' of the teeth forming the next tooth space. In the last described arrange- 70 ment of etifters, the distance between the cutting edges of each pair of tools preferably bears the same ratio to the distance between the last cutting edge of the pair and the initial cutting edge of the next pair of tools, 75 as the width of the base of the tooth space at one edge bears to the distance from the base of one tooth space to the bise of the adjacent tooth space. This is shown in Figs. 22 and 25, where a' is in the same ratio to bl 80 as a is to b. One form of cutter is shown in Fi(, - 20 and embodies a body j)ortion 109 provided with the cutting portion 110, the cutting edge of which is indicated at 111. The tool may be attached to the tool head, 85 as illustrated in IA'igs. 23 and 24, the tool being held in position by means of a bolt 112, and adjustable with relation to the head through a wed(Ye 113, the position of which is determined by an adjusting screw 114 90 baving engagemeni with the tool head and with the wedge. We