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EDWIN, R., FELLOWS, OF SPRING FIELD, WERIYCNT, ASSIGNOR, TO THE FELLOWS GEAR, SHAPER, COWIPANY, OF SPRING-FIELD, VERTEOINT, A. CORPORATION OF VERVIONT. GEAR GENERATING CUTTING INACHINE. Application filed August 29, 1918, Serial No. 251,902. Renewed April 19, 1924. To all whom it may concern. takes place. This relative movement is the 55 Be it known that, I, EDWIN, R. FELLOWs, resultant of combined movements of rota a citizen of the United States, residing at tion and translation, and may be produced Springfield, in the county of Windsor and in any of three ways, that is; first, by giv 5 State of Vermont, have invented new and ing both movements to the gear, in which useful inprovements in Gear Generating Case the resultant motion is the same as 60 Cutting Machines, of which the following is though the gear were rolled on its base cyl 3. Specification. inder on a plane Surface; second, by giving This invention relates to the art of gear both movements to the cutter, when the re cutting, and has particular reference to ma Sultant-- is the same as the motion of any chines adapted to generate, by true mathe point in a line being unwound from a fixed 65 matical generation, accurate involute curves cylinder; or third by giving the movement in the tooth faces, at the same time with of rotation to the gear and the motion of cutting the teeth, of a gear blank. The ob translation to the cutter, these movements 5 jects of the invention include the follow being the same as those occurring8. in an in ing:-first, to provide a machine constructed termeshing rack and pinion gearing when 70 and organized as a whole to be rendered ca the rack is moved endwise and the pinion pable of thus generating and cutting gears is rotated about a fixed axis. In the ma of any size, any pitch, and any angle of tooth chine in which I have embodied the inven face, within the limits imposed by the size tion for illustration in the present speci and proportions of the specific machine, by fication, I have applied the third of the making a few adjustments of the simplest above described modes of producing the nec soit; second, to provide a cutting tool con essary relative generating motion. structed and operated as a milling cutter of Another principle of which I make use, is such form and so mounted that, without the familiar principle of gearing that the change, it is adapted to generate and cut in tooth face of a rack which meshes properly 8) volute tooth curves of all sizes, pitches, and with the teeth of a gear having involute inclinations; third, to make the cutter with tooth curves is a plane perpendicular to the a large number of blades or cutting teeth plane of action of the gear, and that the base located upon part only of the circuit of a cylinder of the gear is a cylinder coaxial cutter head or carrier having great linear with the gear tangent to such plane of ac 85 extent of periphery, whereby the cutting of tion. When the relative motion between the a tooth face may be completed, and the gear and rack is such as to produce the ef work indexed, in the course of one cycle of fect of rolling the gear on its base cylinder, 35 the cutter; and, fourth, to provide in the the tooth faces of the correctly meshing inachine two cutting tools arranged to gen rack, according to this principle, are perpen 90 erate and cut the opposite faces of the same dicular to the length and pitch line of the gear tooth, or the relatively opposite faces rack; that is, in the technical language of of different teeth, and being adjustable as to the art, the angle of the rack is 0°. This 40 their distance apait from one another, thus relation holds whatever may be the pitch of doing in the same time twice the amount of the gear or the inclination of its tooth faces: 95 work performed by a single cutting tool, and wherefrom it follows that a rack tooth face simplifying the adjustments necessary to de of 0° angle will engage properly with a termine the thickness of the teeth. involute gear of any size, pitch, or angle of The principle upon which the invention face. operates is that of generation by relative By making use of the principle last set 100 movement between the work piece (gear forth, and producing relative motion be blank) and the cutting tool, equivalent to tween the gear blank and cutting tool with the movement of a point on an inextensible the effect of base cylinder rolling motion of line being wound upon, or unwound from, the gear blank upon the plane of action, a cylinder in accordance with the mathemat am enabled to use a cutting tool having cut 05 ical law of involute curves; and cutting by ting edges which, when they pass across the simultaneouis travel of the cutting tool across work, have the relation to the gear tooth of a the plane in which such relative movement lack tooth face of 0° angle; and thereby to g 1,516,524 mount the cutting tool for rotation about an adjustments of the very simplest sorts and 65 axis parallel to the plane of action and to that two cutters on the same shaft can be the direction of relative translative displace used for cutting at the same time opposite ment between the gear blank and tool. In tooth faces in straight or helical spur gears. 5 consequence i am able to employ the same In the foregoing statement, the cutter is cutting tool, without adjustment, for gener considered as a single element having a 70 ating and cutting the teeth of gears of all single cutting edge, acting once on the gear sizes, all pitches, and all angles of face, blank in each rotation. Successful commer within the limits of size of the specific ma cial practice requires that there be actually O chine; and to use at the same time two cut many such elements arranged to act in rapid ting tools on the same shaft, or on alined or succession, in the interest of rapid produc parallel shafts, with the effect of doubling tion of work; and have therefore made the output of the machine and determining the cutter with a large number of blades the width of the gear teeth in a simple or cutting teeth, each having a cutting edge 5 ale. arranged as set forth. The principle is So far as I am aware, all gear cutting the same, whether there is one cutting ele 80 machines of the prior art have required a ment or many of them, and the general special cutter for each pitch and type of gear description hereinbefore given applies to to be cut and in machines using milling each of the blades or cutting teeth of the 20 cutters it has been necessary to provide entire cutting tool actually used. In the special cutters for all different sizes of gear cutting tool here shown. I have made the 85 as well. s number of blades or teeth great enough In this specification, because the actual to complete the gear tooth in the course gears cut have substantial thickness, I have of one rotation or cycle of the cutter; and 25. called by the terms “base cylinder”, “pitch in addition, have made the peripheral ex cylinder', and “plane of action', the con tent of the cutter head or blade carrier 90 ceptions which are commonly referred to enough greater than the extent of the series in discussions of gearing as “base circle', of blades to permit indexing of the work “pitch circle', and “line of action', respec in the course of the same cycle, whereby 30 tively. it is unnecessary either to stop the cutter Having designed the machine here shown or to move it out of the way of the Work in accordance with the principles hereinbe for this purpose. fore discussed, the milling cutter is provided The foregoing relates to the main object with a straight cutting edge perpendicular of the invention. Secondary objects are 35 to a line tangent to the base cylinder of the concerned with means for indexing gears of gear blank, and also perpendicular to the certain characters, and various mechanical 00 axis of its cutting rotation, and the holder features and details, all of which can best for such cutter is shifted in the course of be explained in connection with a detailed cutting a tooth of the gear in a line par description of the embodiment of my inven 40 allel to said “plane of action.” tion here presented for illustration. In ad When the machine is designed to produce dition to the fundamental features o' means straight spur gears, as is the particular ma first mentioned, the invention consists in chine here shown, the axis about which the these other features last referred to and cutter rotates is also parallel to the “plane pointed out in the claims. 45 of action', and therefore parallel or co The drawings provided with this speci incident with the directions of this shifting fication illustrate a machine embodying one 10 movement; but in machines for producing form of the invention, though not repre other types of gear, Such as helical and curved senting the only possible form thereof. In tooth spur gears, the relations between such the drawings, 50 axis and the plane of action, the directions FigureS 1 is a front elevation, with a of shifting movement, and the direction of part broken away and shown in section, of 5 the cutting edge, may be appropriately said machine. varied. In any case, however, the cutting Figure 2 is a left hand end elevation. edge is perpendicular to the so-called “plane Figure 3 is a sectional view on line 3-3 55 of action', and the displacement of such of Figure 1, with an adjacent part repre edge, between its positions when in succes Sented diagrammatically. 20 sive rotations it crosses the same plane l'a- Figure 4 is a front elevation enlarged of dial to the axis, is in a direction in or par a fragment of the milling cutter. allel to said plane. It results from this es Figure 5 is an elevation enlarged of so 60 sential condition that the same cutter in much of the milling cutters as appear in the same machine may be used to generate Figure 2. - 25 and cut involute gears of all sizes, pitches, Figure 6 is a plan view of the machine. and tooth angles, within the limits of ad Figure is a horizontal section and plan justment of the machine for size, by making taken on line 7-7 of Figure 1.

1,516,524 S. Figure 8 is an elevation of a fragment doing work on another tooth in the course of the machine bed, showing certain ad of one complete rotation of the cutter head. justing means. I also preferably provide two cutter heads Figure 9 is a left hand end elevation and on the same shaft, each having its complete 5 Vertical Section on line 9-9 of Figures 1 set of blades of inserted cutte's in order that 7) and 7. two tooth faces may be cut at once. Prefer Figure 10 is a horizontal section illus ably also the cutters of one head are the re trating a detail of the cutter and the drive versed duplicates of the other, whereby the for the same. One cutter tool may generate One face of a Figure 11 is a vertical section on line tooth of the gear, and the other cutter tool 11-11 of Figure 7. may generate the opposite face of either the Figure 12 is a vertical section of iiie same tooth or of a different tooth; and where 12-12 of Figure 2 and an elevation of the by also, by adjustment of the cuttei' heads parts at the right of Said line. axially, the width or size of the finished gear e Figure 13 is a section on the line --- 3 teeth may be determined. One cutter head 80 of Figure 2. is indicated 32 and the cutters carried there Figure 14 is a detail elevation of the in by are designated 33. Such head has a hub dexing mechanism. 34 which fits on a tapered part of the cut Figures 15 and 16 are fragmentary details ter shaft, and is secured by a nut 35. Pref enlarged of a part of the indexing can erably it is also keyed to the shaft. The rim showing the same in two different posi or peripheral part of this head is provided tions. On One side with grooves in which the cut Figure 17 is a detail cross section on line ters are placed, and carries clamps 36 for 17-17 of Figure 14. Securing the cutters detachably in place. 2 5 Figure 18 is a diagram illustrating the The head also has an axially extending 90 manner in which the cutter acts to generate flange 37 with internal teeth, thus forming the tooth curves in the gear blank. an internal geal adapted to mesh with the The same reference characters indicate the driving pinion latei described. This is a Same parts in all the figures. convenient, although not essential, driving The machine base 19 Supports a bed 20, connection, and othel' mechanisins may be 95 whereon is a carriage 21 having a bearing used for the purpose, if desired. 22 in which the cutter shaft 23 is mounted The other cutter head is designated 38 to turn; and said base is also provided with and it has a similar rim adapted to hold the a head 24 having a bearing sleeve 25 for cutters 39, and equipped with cutter-hold 3 5 the spindle 26, which carries the work piece ing clamps 40. This cutter head is adjust O) 27, the latter being the gear to be cut. In able lengthwise of the shaft, and is prevent the drawing two gears are shown as being ed from turning thereon by a spline 41. The cut the same time, but it is feasible to mount distance between teeth 39 and teeth 33 is de a single gear only on the spindle in correct termined by an adjustable collar 42, which 40 position to be cut. Rigid with this spin is threaded on the shaft 23 SO as to bear 05 dile, being keyed thereo, is an index wheel against the Outer end of the hub 43 of cut 28, the same being made as a worm wheel ter head 38. Instead of holding the latter which is driven by a worm 29 on a shaft, 30 cutter head rigidly between fixed or ad having bearings in the box 31 mounted on justable abutments, prefer to provide the side of the head 24. Spring plungers 44 which are carried by the O head 38 and are arranged to press against Generating and cutting means. the cutter head 32 so as to hold the hub 43 For the purpose of giving the required against the collar or nut 42. These plungers relative generating movement between the are mounted in guides in the cutter head 38 cutter and gear, the lattei' is rotated at a and are pressed upon by Springs 45 which 5 determined rate of speed by the worm and react against plugs 46; the preferred con index worm wheel, and the cutter is at the struction and arrangement of these parts be Same time shifted bodily. The entire cut ing clearly shown in Figures 7 and 10. ting tool is hel'e shown as composed of a The Spring plunger's take up all looseness large head carrying a number of inserted or play between the cutter heads, and make blades Ol' cutting teeth, each of the blades it possible to adjust the distance between the being a catter complete in itself, but a suffi two sets of cutters accurately by the col cient number of the blades being provided lar 42 alone. on the One head to complete the side of One The cutting edges of all the cutters of 60 tooth; and the head being large enough to both sets are designated by the single nu mount all of these cutters on a part, which meral 46. These edges are arranged on is considerably less than the whole, of its such a bevel that when the cutters are prop circumference. This arrangement makes it erly positioned in the heads, the edges of possible to finish a tooth of the gear blank each Set are in a plane perpendicular to the 6 5 and return the cutter tool into position for axis about which they rotate in cutting. 4. 1,516,524 Thus said cutting edges correspond, in their briefly characterized as a tool or instru relation to the gear being cut, to the face of ment comprising a carrier and an inter a rack tooth of 0° angle adapted to mesh rupted series of blades or teeth mounted on with the gear, and when moved translatively said carrier for travel in a closed path. A at the same speed as the linear movement tool having such characteristics may be () of a point or the base cylinder of the gear, made otherwise than with a rigid circulai (the latter being turned about its axis at cutter head as the carrier. the same time), such cutters are enabled to generate correct involute curves in the faces A riving mechanism. O of the gear teeth, according to the mathe Power for producing the motions des natical law of involute curves and the prin cribed is applied by a belt (not shown) to a cipies of gearing previously hel'ein ex pulley 51 on a shaft 52 which is mounted plained. The advantage of this arrange in the manner presently described upon a ment of the cutting edges is that the Same casing 53 secured to the side of the head 24. 5 cutters are adapted to generate teeth of any Said shaft carries a pinion 54 (Fig. 3) which SO pitch and of any angle or inclination of meshes with an intermediate gear 55; the tooth face, within the limits of the machine, latter being coaxial Vith, and normally con and it is not necessary to Substitute a cutter Inected to a gear 56 which meshes with a of special angle, for; or size for gears of pinion 5 on the shaft 30, previously de different pitches and different tooth angles, scribed as carrying the Worm for driving as is the case in all prior inachines and the Work. 57 is a change gear and has nethods used in gear cutting of which I either the same number of teeth as the gear have knowledge. to be cut, or a multiple of Such number of For moving the cutter axially in unison teeth. Gear's 55 and 56 are of the same size 2. 5 with the rotational movement of the Work, i. and have the same number of teeth as the 90 have provided a cam 47 which is keyed or index worm wheel 28. They are mounted otherwise mounted on the cuttei' shaft 23 on a shaft, 58 carried by a quadrant or Swing so that it cannot turn thereon, but is remov frame 59 which includes in its construction able to permit substitution of other cams a sleeve 60 Surrounding and making one of 30 of different pitch and is claimped by a nut the bearings of shaft 52, and fitting in a 95 48. This cam is essentially a rib offset in bearing box (31 (Figure 13) secured to the the required manner axially of the shaft, casing 53. Thus the gears 55 and 56 may and projecting between two abutment rolls be adjusted to accommodate the latter to 49, 50 which are relatively fixed in position, change gea's 57 of different sizes. In each 35 although adjustable for purposes presently adjustment the Swing frame of quadrant is described. This calm is so designed that it made fast by a bolt 62 passing through a gives a gradual uniform movement of trans flange 63 on the box 61 and threaded into lation to the cutters from the commence one of the aims of the Swing frame 59, as ment to the end of their action. upon a tooth shown in Figures 3 and 13. A second bear 40 face, and after finishing a tooth, it returns ing for shaft 52 is provided in 61, a part the cutter to starting position. of the casing 53. As previously indicated, one feature of Gear 55 is keyed to shaft 5S, and gear 56 the invention for which I claim protection, is loose on Said shaft but is normally although without limiting my main claims coupled to the shaft by a clutch 64 splined thereto, is that each cutter head is Suffic to the shaft and having a tooth or shoulder O iently large, and the number of cutter's or 65 (Figure 2) engaging a complemental blades carried thereby sufficiently great, to tooth in the end of a sleeve 66 on which the enable each cutting operation to be com gear 56 is fixed. pletely carried out during a part only of The shaft 52 carries also a pinion 67 one rotation of the head. In the specific de (Figures 2, 6,9) in mesh with a gear 68 on sign here shown this partial rotation is ap a shaft 69 (Figure 7) carrying a bevel gear proximately, or slightly more than, two 70 in mesh with a bevel gear 71 which is thirds of a rotation, and the cutter blades splined upon a shaft 2 passing through the are therefore mounted on approximately the head 24 and supported in a bearing 73 which 5 5 same proportion of the cutter head, leaving is carried by the carriage 21 whereon the the remainder of the head without cutte's bearing 22 for the cutter shaft is mounted. so that it will clear the work on the return The bealings for shaft 69 and for the hub travel. Any other proportion between the Or sleeve of gear 71 are structurally parts part of the head occupied by cutters and of the casing 53. A bevel gear 74 on the 60 the part which is left blank may be adopted end of shaft 72 drives a bevel gear 75 on a according to the specific nature of the work shaft. 76 which carries a pinion 77 in mesh being cut, limited only by the permissible with the internal gear teeth of the cutter steepness of that part of cam 47 which re head flange 37. The last named pinion and turns the cutter to starting position. The internal gear have wide faces to permit the cutting instrument thus described may be axial movement of the cutters previously 30 1,516,524. is described. The splined connection of shaft that the linear travel of its base cylinder is 72 with gear 71 permits movement of said equal to the rate of displacement of the cut shaft endwise with adjustments of carriage ter in Such “line of action', the desired result 21, later described. of correctly generating tooth curves will fol The rotation thus imparted to the cutters low whatever may be the specific nature of 70 is transmitted to the shaft or spindle 23 the gear. carrying them, and thereby the cam 47, car The displacement above referred to as ried by said shaft, is caused to impart the taking place in a line tangent to the base feeding and return movements to the cut cylinder of the gear, refers to the displace ter as already described. Thus the cutter ment of the cutting points of successive is moved and the blank is rotated by mecha teeth or cutter blades when they cross such nisms deriving power from the same source line. Actually of course the travel of each and operating in unison, such mechanisms cutter is a helix, compounded of the rotation being of positive character throughout and of the cutting point and the linear travel of thereby effecting exact synchronism in the the entire cutter tool, but the displacement 80 movements of the cutter and work in the or the shifting of the cutter referred to in manner required for the purposes set forth. this specification and claims is the displace The exact manner in which the cutter is ment between successive positions of the all'anged with respect to the gear blank and Sane cutting point in the same line tangent 20 the manner in which it performs its gener to the base cylinder of the gear. Where ating function are illustrated in Figure 18. used in the claims without other qualifica Here the cutters 33 and 39 are each illus tion, the term “displacement’ and the term trated in three different positions, as 33, "shifting' as applied to the movement of 33, and 339; and 39, 39, and 399, respec the cutter other than its rotative cutting 25 tively; the cutter 33 being engaged with the travel, are both to be construed with the 90 right hand face of a gear tooth A and cut meaning above indicated. tel' 39 with the left hand face of a gear tooth B. Different positions of these gear teeth Indeaving mechanism. corresponding to the positions of the cutter 30 are designated A, A, and A8; B, B2, and It is apparent from Figure 18 that during B°, respectively. The cutter 39 first engages the cutting of one tooth face the gear is the tooth B at the tip thereof and the posi turned through an angle approximately equal tion of engagement shifts along the face to a to the angle subtended by three teeth. That point near the root of the tooth; while the is, from the time that the cutter 33, for ex 3 5 cutter 33 engages tooth. A first near the ample, first engages the root of a tooth at 'Oot of the latter and the point of engage the tangent point between the base cylinder ment shifts outward to the tip. Adjacent and the plane of action until it leaves the tip to the several indicated positions of the cut of the tooth in the position 33°, the gear has ters are dotted line constructions represent turned through the angle of three teeth and 40 ing rack teeth having faces of 0° angle, to their adjacent spaces, approximately. And 05 which the cutting edges of the cutters cor since the gear is rotated constantly in the respond, as previously explained. The point Same direction, not only during the cutting in each citter which finishes the gear tooth operation but also while the cutting tool is re face to exact size and form is displaced in a turning to starting position after having com line designated in this drawing “the line of pleted a cut, it is clear that a certain number 10 action', which is the intersection of the plane of the gear teeth are skipped between cuts, so of the drawing with the plane of action be that each succeeding cut is made, not on tween the gear and the rack of 0° face angle, the next following tooth, but on one several and tangent to the base cylinder of the gear. spaces back of the tooth last finished. The Evidently the resultant relative movement exact time of cutting a tooth, measured in 5 between the above specified point in each terms of the angle turned through by the cutter and the gear blank is that which de gear during that time, will vary with the Scribes an involute curve, since the linear size of the gear and the pitch of its teeth, velocity of the gear base cylinder is equal and the time needed for returning of the to the rate of displacement in said line of cutter, measured in the same terms, may be 120 the cutter. The point at which this line in of any value, from considerably less than tersects the edge of the cutter is the cutting the time of rotation of one tooth up to any point which generates and finishes the tooth part of the rotation of two or more teeth. curve, while the cutting edge adjacent to The cutting travel and return travel to that point and on each side thereof removes gether make the cycle of the cutter, and the 125 surplus stock, leaving to said point the duty return travel is designed to complete the only of cutting down the surface to the final cycle in the time of rotation of a whole num form. Provided only the cutting point thus ber of teeth, and also in the shortest possible identified is displaced along the “line of ac time. Now, if the total number of teeth of tion” and the gear is rotated at a rate such the gear being cut is the multiple of the 130 6 1,516,524 number which pass a given point during 103, thus disconnecting gear 56 from shaft, One cycle of the cutter, the finished teeth 58 and interrupting the driving train to the will ultimately come into register with the Work piece, which then stands still. cutter again and the intermediate teeth will The value of the gear train from shaft not be cut at all. In order to prevent this 52 to timing disk 8 is such that the timing O result in such a case and cause all the teeth disk turns at the same angular velocity as to be cut automatically, I provide an index the gear blank. After said disk has caused ing mechanism which changes the relation disconnection of the clutch in the manner of the gear to the cutter when the gear has described, it restores the clutch into the 0. completed nearly a complete rotation, or in coupled position so that the gear train to 5 other Words, when the next tooth about to the Work piece is completed, and the latter come into position to be cut is the one which again set in motion when the shaft 5S has was first finished. In this machine the re made a complete rotation. Since the gears quired change in such relation is effected by 55 and 56 have the same number of teeth 5 causing the gear to remain stationary for a as the index wheel 28, and gear 57 the same period equal to the time of rotation through number of teeth as the work piece, it is evi the angle subtended by one tooth and the dent that one revolution of the gear 55 adjacent tooth space, or a multiple of that turns the Work piece through the angle sub time. tended by one tooth, when the worm 29 This mechanism comprises a worm or driving the index wheel has a single thread S 5 screw 81 on shaft 52, a gear train consisting whereof the pitch is equal to the pitch of of a worm wheel 82 (Figures 9 and 12) in the index wheel, and that stopping gear 56 mesh with the worm 81, pinion S3 on the while gear 55 makes a complete turn causes shaft 84 of said worm wheel, intermediate the work piece to stand still for the time re 25 gear 85 in mesh with pinion. 83, and a quired to turn it through the same angle. change gear 86 in mesh with the intermedi For some classes of work it may be neces ate gear; timing disk 87 on the shaft 88 of Sary to provide a change. gear 57 having a gear 86, and a lever 89 controlled by said multiple of the number of teeth of the work timing disk and effective to throw clutch 64 piece, or the Work may be required to stand 30 into and out of gear. Shaft 84 above men still for the time of rotating through the tioned is mounted in a bearing sleeve 90 angle of two teeth. In either... case the projecting from the casing 53, and gear 85 clutch Would need to remain uncoupled is mounted on a stud 90 carried by a holder While the gear 55 makes two or more turns, 91 clamped upon said sleeve and adapted to and the means which I have provided and 35 be turned about the same. The shaft, 88 is will now describe for coupling the clutch CO mounted in a bearing sleeve 92, which also takes care of this condition. projects from the casing 53. Lever 89 (Fig As the disk 8 turns at a relatively very ures 2, 9, and 14) is a bell crank pivoted on slow speed, some other means than a cam a stud 93 and provided with a foot 94 on Surface must be provided to return the lever 40 One arm, which rests on the rim of the disk 89 to the position for coupling the clutch. 87. The second arm of the lever carries a The shoulder at the advancing side of the fork 95 which embraces a head 96 on a plun notch 107 may be made l'adial to the cam, or ger 97, and carries studs 98 projecting into undercut if necessary; thus permitting as a groove 99 in Said head, making a coupling rapid movement of lever 89 as may be nec 45 of well known character. Plunger 97 is essary to uncouple the clutch, but no in IO mounted so that it may move endwise in a clined surface as a part of the disk could be guide 100 and is pressed upon by a spring designed to again couple the clutch within 101, thereby exerting force on the lever so the time available. Hence, for the purpose as to press foot 94 against the rim of the of returning said lever with sufficient speed, 50 cam. To the plunger 97 is connected by a have provided an ejector in the form of 5 pivot 102, a lever 103 having a fork which a plunger 108 which is carried by the disk, embraces the clutch 64 and carries pins en and a co-acting Fetractor or stop 109 for the tering a groove 104 in the latter. This plunger. Said plunger extends through an lever has its fulcrum on a pin 105 mounted Opening in the rim of the disk and is pressed 55 in arms 106 which project from the quad upon by a spring 110 so that its end is con 20 rant 59 (Fig. 2), previously described as stantly urged radially outward. The stop carrying the shaft 58 and gears 55, 56. 109 is fixedly mounted on the side of the Clutch 64 is normally held engaged with machine frame over an encircling groove the sleeve or hub 66 of gear 56 by the rim 111 in the perimeter of the disk, and its end 60 of the timing disk 87 acting through lever projects into such groove. The foot 94. 88, plunger 9 and lever 103. In the rim of however, rests on a flange at One side of this the disk is a notch 107 which, when it ar groove. The end of the plunger crosses the rives under the foot 94, allows the latter to notch 107, and the stop 109 is close to the drop, and permits the spring 101 to throw lever foot 94, the arrangement being such clutch 65 out of mesh by swinging lever that when the foot enters the notch, the 3) 1,516,524 r plunger has already been pushed back by gear were allowed to turn uniterruptedly. the stop. As the disk continues to rotate, All the teeth are then cut while the gear the rear edge of the plunger is carried past nakes three rotations, or in general terms, the stop, and as soon as it is clear thereof, iotates a number of times equal to the num the plunge) is suddenly shot outward by its ber of teeth between successive cuts. 70 spring, thereby instantaneously moving Where the number of teeth in the gear lever 89 and shifting the clutch into cou being cut is not a multiple of three, having pling position. The stop 109 is made ad regard to the machine here shown, Ol' to justable backward and forward in the gen state the same proposition in general terns eral direction of rotation of the adjacent when the number of teeth comprised between 75 part of the disk, whereby the time elapsing successive cuts is not a divisor of the number between the passing of foot 94 into the of teeth of the gear, the indexing device is notch and release of the plunger may be unnecessary and may be dispensed with, the regulated as desired. Of course the plun controlling disk being then made inopera ger is SO formed and proportioned as to tive by disengaging gear 85 from the change 80. move suddenly in the manner described, and gear 86. to permit of the adjustment described. By As the cutter tool makes a complete rota thus adjusting the stop it is possible to hold tion in the course of each cycle, the part of the clutch out of action for One, two, or its periphery occupied by cutting blades more rotations of the shaft 58. bears approximately the same ratio to The need of providing the additional lever the unoccupied part as the ratio of the time 103 in the clutch operating connections, in of cutting travel to the time of the retuin stead of operating the clutch directly by travel. lever 89 arises from the necessity of mount Adjustments. 2 5 ing the gear 56 to Swing into engagement 90 with change gears 57 of different diameters, Substitution of gears of different values the result of which is that the clutch is for the change gears 57 and 86 enables the placed in different planes, while the disk Work piece and disk to be rotated at such and lever 89 remain in the same plane. To different angular velocities that gear blanks all intents and purposes, however, the lever of different pitches and diameters, and dif 95 89 is the clutch shifter in spite of the fact ferent tooth angles, may be cut, since by that it accomplishes this office indirectly that means a gear blank of any diameter, instead of by direct engagement with the capable of being placed in the machine, may clutch. Plunger 97, with lever 103, make be rotated at any desired angular velocity 5 a form of universal joint between such to give it the same linear motion. On the 00 clutch shifter and the clutch. The plunger base cylinder (whatever the diameter of is the pivot of this universal joint and is in such base cylinder inay be), as the displace alinement with shaft 52. ment travel of the cutters. While Figure 18 shows the time of cutting The controlling cam 47 must be made 40 the gear tooth to be nearly the time of ro special for each pitch, and that part of it 05 tation of the gear thi'ough the angle of three which displaces the cutters in their cutting teeth, the condition there shown is not the travel is made as a helix of pitch such that one most commonly met in practice; for the linear displacement of the cittel's is with gear's of the sizes and pitches more equal in extent and speed to the linea’ love 45 generally used, the cutting operation will be inent of the gear blank base cylinder. Other coinpleted in approximately the rotation wise the proportions of the cam are so de through the angle of two teeth, and the en signed that the part which returns the cit tire cycle of movements of the cutter will ters may serve the intended purpose with occur while the gear turns through the angle out shock and without applying an exces of three teeth. Therefore, the particular sive thrust, on the rear abutment roll 50. 5 machine shown in these drawings has been As the cam is mounted on the exposed real' designed to cut every third tooth of the gear, end of the cutter spindle and secured by a and to index the gear by stopping its rota nut, it may be removed and another substi tion for the time of turning through the tuted as readily as an exchange of change 55 angle of one tooth when the n-2nd tooth has able gears may be made. While the complete been cut, (n being the number of teeth of equipment of a commercial universal ma the gear, and being a multiple of three). chine requires cams capable of giving two-, The effect of the indexing thus described is three-, and four-tooth feeds to the cutters to cause the cut, which takes place follow for each pitch of gear, certain cams may 60 ing the indexing to be made on the second perform double duty, since a two-tooth feed 125 tooth following the one last cut instead of can for a four pitch gear is the same as : the third tooth; or more broadly stated, is to four-tooth feed can for an eight pitch gear, cause the number of teeth intervening be. and so forth. 4. m tween successive cuts to be different from The cutters may be adjusted to gears of the number which would intervene if the different diameters by moving the carriage 30 3. 1,516,524 2} on the bed 20, such carriage having for ing to the longitudinal elements in the face this purpose a bored and threaded lug 112 of the tooth to be cut. meshing with a screw 113 which has its It is also within the purview of my inven bearing in a bracket 114 on the base; such tion to arrange the cutter elements or blades, Screw extending titansverse to the line of 33 or 39 of the cutter tools in appropriate 70 travel of the cutters. . specifically different manners for cutting Longitudinal adjustment of the cutter straight spur teeth without axial displace spindle is made possible by nounting the ment of the cutter head; or for cutting other rolls 49, 50 which confine the cam 47 of the types of gears, such as those having curved 10 cutter spindle, in a slide 115 fitting a guide teeth. In every embodiment of the inven 5 116 on the cutter carriage, and by providing tion, however, the essential relation of the a screw 118 on the cutter carriage to engage cutting edge perpendicular to the line of a threaded part of said slide (see Figs., 8, action of the geal when in the cutting posi and 1j). Said rolls 49 and 50 are mounted tion, and being displaced so that the suc 5 On studs which occupy passages in the side cessive positions of the cutting point, or 115, in which they are movable endwise. points on the work are displaced in this Screw abutments at the end of said rods line of action, persists, whereby the funda serve to adjust then to take up lost motion mental object of enabling teeth of all charac between the cam and rolls, which are com ters to be cut in the manner described is at 20 plementally beveled for that purpose. tainable in all cases. The gear blank teeth may be adjusted to The machine above described is particu the generating wheel by shifting the worm larly intended to be used for accurately 29 endwise. The bearing for one end of the finishing gears which have previously been worm shaft is a sleeve 119 (Figure 9) roughed out by other methods, and it is used 25 threaded into the Wom box 31, and pro in cases where a high degree of accuracy is 90 vided with an adjusting hand wheel 120, needed but it is not necessary to harden and such sleeve and the shaft, and worm being grind the gears; although, of course its Scope formed and proportioned to prevent end of usefulness is not necessarily thus limited. shake of the latter. A cover sleeve 121 se in the operation of this machine the gear 30 cured to the hand wheel stirrounds the ad blank to be cut or finished is mounted on the 95 jacent part of the worm box and is gradu spindle 26 and the cutter is adjusted to ated so as to measure, with reference to in bring the tips of its teeth up to the line of dex marks on the worm box, the exact ex action; the proper changeable gears having tent of adjustment. A set screw 122 secures first been placed in the location of the gears the adjustments of the bearing sleeve. 57 and 86 according to the character of the 0. Thus it will be seen that any adjustment gear to be finished. Then the machine is: involves at most only the changing of two started and simultaneously the cutter re changeable gears and a cam, and the turning volves and is shifted bodily in its line of of three adjusting screws. No other change travel, and the gear blank slowly rotates 40 is required, and in particular there is no with a linear speed at its base cylinder equal 03 necessity for substituting a different cutter: to the rate of displacement, travel of the cut and as a corollary it is not necessay to pro ter. During the forward displacement of vide a large number of different cutters for the cutter the entire series of teeth or blades completely equipping the machine, as is the On the two cutter heads sweep across the op 45 case with gear cutting and generating ma posite faces of two teeth of the gear blank, )) chines of the types previously known. Al cutting such tooth faces to the final finished though in the construction here shown there size and involute form. When the blank are many cutting blades or elements, these spaces of the cutter heads arrive opposite elements are all alike, and they do not re the gear blank the cutter carriage is with quire to be substituted or altered except as drawn, and the cycle is repeated, the gear 5 they become worn or damaged. A machine blank meanwhile being constantly rotated in embodying the principles herein explained the same direction and at the same speed. in which the cutting tools are formed with The same action continues without interrup fixed cutting elements or teeth instead of the tion until the entire gear is finished, in the detachable blades here shown is within the case where the number of teeth on the gear protection of my claims. blank intervening between successive cuts Various modifications in the construction is not a divisor of the whole number of its and arrangement of the several parts of the teeth. In the other case, the indexing mech machine will readily occur to any one skilled anism goes into operation from time to time in the art. All forms of gear may be gen to arrest the rotation of the gear blank for erated and cut by milling cutters having a a time equal to that required for a given straight cutting edge or a series of such number of teeth of the gear blank to travel edges perpendicular to the plane of action past a given point. of the gear, where such cutting edges are so In the machine as illustrated and de mounted as to travel in a path correspond scribed no provision is made for travel dur 156,524 9 ing the cutting operation of the work piece Such line at a speed equal to the linear we in the direction of its axis, or for any equiv locity of said base cylinder and in the direc alent displacement of the cutter in this tion of travel of that part of the base cylin direction. No such displacement is neces der which is tangent to said line. sary in any case where the length of the gear 4. A gear generating cutting machine 70 in the axial direction is so small in proportion comprising a gear blank holder, means for to the radius of the cutter that the deviation rotating a gear blank to be cut which is of the line in which the end of the cutter mounted on said holder, a cutter tool rotat tooth travels from the straight line parallel ably mounted and comprising a number of O to the axis of the gear, within the length cutting elements each having a cutting edge 75 of the gear tooth, is no greater than the which is brought during the rotation of the clearance provided in the gear tooth space. tool to intersect a line tangent to the base That is, all gear's have clearance spaces be cylinder of the gear blank, each edge at the tween their teeth within their base circles, time of intersection with such line being 5 as is shown in Figure 18 of the drawings, perpendicular thereto, and provisions for 80 and Such spaces may be made deep enough causing the successive cutting edges when to permit travel of the extremity of such a crossing such line to be displaced in the di cutter tooth as here described, when the rection of linear travel of the tangent point path of such extremity extends as far as the of the gear blank base cylinder by distances 2C) Jase circle at the ends of the gear blank equal to the linear travel of Said base cylin 85 teeth, within the practicable limits of diame der in the intervals between the arrivals of te' of the cutter provided to cut gears of successive cutting edges in the positions set Ordinary lengths. forth. What I claim and desire to secure by Let 5. A gear generating and cutting machine 25 ters Patent is: comprising a rotatably mounted milling cut 90 1. A gear generating cutting machine ter having a cutting edge in a plane perpen comprising a rotatable milling cutter having dicular to the axis about which it rotates a cutting edge of which the cutting travel and means for mounting a gear blank to be takes place around the axis of the cutter, cut with the base cylinder thereof tangent 30 in a plane perpendicular to Such axis, a gear to a line which is parallel to said axis and is 95 blank holder arranged and adapted with re also within the path of the extremity of said spect to said cutter to support a gear blank cutting edge, and means for producing such with the base cylinder thereof tangent to a a combination of relative rotative and trans straight line which crosses the path of said lative movements between said gear blank 35 cutting edge and is perpendicular to the plane and cutter as to cause the point of intersec 00 of such path, and means for producing a con tion between said line and said plane to de tinuing movement of relative translation on scribe an involute curve relative to the base the part of the cutter and rotation on the part cylinder of the gear blank. of the gear blank which is equivalent to the 6. A machine as claimed in claim 1 dis AO resultant motion of a point. On an inexten tinguished by adjustable driving and posi (5 sible line being wound upon or unwound tioning means for changing the relative mo from the circumference of a circle. tion between the gear blank and cutter 2. A gear generating cutting machine whereby to generate the curves of gear teeth comprising a rotating milling cutter having of different pitches, sizes, and inclinations a straight cutting edge, the relation of which of face. to the tooth to be generated is that of a rack 7. A gear generating cutting machine tooth of 0° angle, means for holding a gear comprising a rotatable gear blank holder, blank with the base cylinder thereof tan means for giving the same and a gear blank gent to a line which is at the same time per mounted thereon a slow rotation about the pendicular to Said cutting edge and to the axis of the blank, a milling cutter having direction of cutting movement thereof, and a succession of cutting points mounted to means for producing relative shifting move rotate in a path perpendicular to and inter lients between the gear and cutter equiva secting a line which is tangent to the base lent to those movements resulting from roll cylinder of the gear, and means for shifting 55 ing the gear blank on its base cylinder along said cutter bodily in a path extending in the 20 such line. same direction as said line, whereby the cut 3. A gear generating cutting machine ting points when coming into action on the comprising a rotating milling cutter having blank are always in said line, Said shifting a straight cutting edge, means for holding means being organized to displace the cutter 60 a gear blank with the base cylinder thereof at a speed equal to the linear travel of the 25 tangent to a line which is at the same time gear blank base cylinder and in the same di perpendicular to said cutting edge and to rection as the tangent point of Said cylinder. the direction of cutting movement thereof, 8. A machine as set forth in claim dis means for rotating the gear blank, and tinguished by positive driving gear trains 65 means for shifting the cutter lengthwise of from a common source of power effecting 30 O. 1,516,524 the rotating movement of the gear blank and blank, and means for temporarily discon the shifting movement of the cutter in exact tinuing the rotation of the gear blank holder, synchronism. while the cutter is being shifted, for a time 9. A gear generating cutting machine long enough to index the gear blank with comprising a driver, a rotatable holder for respect to the cutter. 70 the gear blank to be cut, a positive gear 14. In a gear generating and cutting ma train from said driver to said holder for ro chine the combination with a cutter instru tating the blank, a rotatable milling cutter ment and a holder for the same movable in having a cutting edge arranged to travel in a straight line, a rotatable gear blank holder O a path. which crosses, perpendicular to, a arranged to support a gear blank with the 75 line tangent to the base cylinder of the gear base cylinder thereof tangent to the line in blank, which line is in a plane perpendicular which the generating point in said cutter is to the axis of the gear blank and between the displaced by such movement of the holder, opposite, faces of the blank, said cutter being means for moving said cutter holder back shiftable bodily parallel to said line, and and forth, means for continuously rotating 80 positive gearing from the aforesaid driver the gear blank holder at a rate which causes constructed and arranged to so shift said the linear velocity of the gear blank base cutter in unison with rotational movement cylinder to be equal to the velocity of dis of the gear. placement of the cutter in its cutting travel 20 10. In a gear cutting generating machine and means for stopping the rotation of the 85 the combination with means for supporting gear blank holder from time to time for a and rotating a gear blank, a milling cutter period long enough to cause indexing of the having a series of blades or cutting teeth gear blank relatively to the cutter. with cutting edges all traveling in the same 15. A gear generating and cutting ma 25 circuit, and means for shifting said cutter chine comprising a rotatable holder for the 90 simultaneously with the rotational move gear to be cut, an index wheel on said holder ment of the blank, a distance sufficient to for rotating the same, gearing for driving generate the face of one tooth thereof, and said index wheel, a translatively movable then returning the cutter to starting posi rotary cutter, means for shifting said cutter 30 tion, the Series of Said cutting elements being in unison with the rotation of the gear while 95 interrupted to permit such return without cutting, and back to starting position, and interference with the blank. means for temporarily disconnecting the 11. In a gear generating and cutting ma driving gearing of said index wheel in one chine the combination with a rotatable hold of the return movements of the cutter, where 35 er for the gear to be cut, an index worm by to index the gear relatively to the cutter. 00 wheel attached to said holder, a driving 16. In a gear generating cutting machine, Worm for said wheel, a rotatable milling a gear blank holder, a driving gear train cutter having a straight cutting edge, a rec for rotatinor said holder and the blank car tilinearly movable carriage holding said cut ried thereby, said train including a loose 40 ter, a cam mounted on the cutter spindle gear wheel and a disconnectible clutch for constructed to cause endwise shifting of the imparting motion to the latter, a cutter, latter and of the cutter, and a stationar means for shifting said cutter in unison with abutment coacting with said cam. - the rotation of the blank, and back to start 12. In a gear cutting generating machine ing position, and a controller for causing 45 the combination with means for supporting disconnection of said clutch in the course of O and rotating a gear blank, a milling cutter, certain predetermined return movements of means for displacing said cutter simulta the cutter. neously with the rotation of the gear to 17. In a gear cutting machine a gear blank generate the tooth curves of the gear, said holder, a gear train including a worm and 50 means being effective also for returning the wheel drive for rotating said holder at a 5 cutter to starting position after completion slow speed, and including also a transmis of a cut, and means for temporarily inter sion gear wheel, a driving element with mitting the rotation of the gear blank dur which said gear wheel is loosely engaged ing return of the cutter, which intermission and a disconnectible clutch between said 55 indexes said blank. driving element and gear wheel, a cutter 120 13. In a gear generating and cutting ma-. arranged to act on a gear blank carried by chine the combination with a milling cutter said holder and being movable translatively and a holder for the same, of a gear blank in unison with the blank and back to start holder arranged to support a gear blank ing position, and a clutch-controlling means 60 with its rim crossing the line of action of arranged to cause disconnection of said 25 said cutter, means for continuously rotating clutch once in the course of a complete ro said gear blank holder, means for simulta tation of the gear holder for a time equal neously shifting said cutter in the same di to that required for a whole number of teeth rection and at the same speed as the linear of the gear blank to pass a given point. 65 movement of the adjacent point of the gear 18. A cutting machine as claimed in claim 30 4,516,524. 17 in which the clutch controlling means tion arranged to come adjacent to the blank comprises a clutch shifter, a timing mem during the return movements of the cutter. ber constructed to cause operation of 24. A gear generating and cutting ma Said clutch shifter at a given point and chine comprising means for holding and ro 5 means for driving said timing member at a tating the gear to be cut, a rotatably mount () rate in given proportion to the rate of rota ed milling cutter having a series of cutting tion of the gear blank holder. blades arranged to act in succession upon 19. A gear cutting machine as claimed in a tooth of the blank, means for shifting claim 17 in which the clutch controller Said cutter in unison with the gear tooth O means comprises a clutch shifter, a rotatable on which it acts, and for returning it to 75 timing disk on which said clutch shifter starting position, there being a space be bears and having a notch into which the fWeen the beginning and ending of the series bearing part of the clutch shifter may enter of blades which space is brought beside in uncoupling the clutch, means for driving the gear blank during the return movement Said disk at the same speed as the gear blank, of the cutter. 80 and a relatively movable ejector carried by 25. In a gear cutting and generating na the disk arranged and controlled to displace chine a milling cutter mounted for rotation the bearin or part of said clutch shifter Sud and also for displacement, means for moving denly from Said notch. Said cutter back and forth in said line and 20 20. A gear cutting machine as claimed in simultaneously rotating it through a com claim 17 distinguished by the clutch con plete rotation in the time of the cycle of trolling disk having a notch, by a plunger its displacement movements, the cutter hav carried by the disk and adapted to pass ing a Series of blades Occupying a part of from the bottom of said notch outwardly, its periphery, the remainder of such pe 25 and by means for causing retraction of the riphery being blank, the ratio of the part 90 plunger to permit entrance of the clutch occupied by said blades to the blank part shifter into the notch, and subsequent Sud being approximately equal to the ratio of den outward movement of the ejector to the time of displacement of the cutter in expel said bearing portion. One direction to the time of such displace 30 21. In a cutting machine according to ment in the opposite direction. 95 claim 17, a disk having a notch in its pe 26. In a gear generating cutting machine riphery, a plunger guided in the disk to a rotatably mounted milling cutter, a hold be movable from the bottom of said notch er for the same movable back and forth toward the mouth thereof, a spring acting in a given line, a cam engaged with said 35 on said plunger tending to project the same holder and constructed for so moving it, 00 in the direction indicated, and a retractor means for rotating the cutter completely located in position to bear upon said plunger in the time required for the complete cycle So as to retract the same during rotation of of back and forth movements of said holder, the disk, said retractor having a terminal Said cutter comprising a series of blades 40 shaped to per'}}ait. Sudden projection of the Occupying a part of the circuit in which 05 plunger when the latter has passed clear said cutter rotates of which the ratio to thereof. the whole circuit is approximately equal to 22. A cutting machine as set forth in the ratio of that part of the cam which dis claim 17 having a rotatably mounted disk places the holder in one direction is to the provided with a notch in its periphery and entire cam. O a circumferential groove crossing said 27. The combination with a gear blank notch, a plunger carried by the disk located holder rotatably mounted and adapted to at the intersection of Said groove and notch, carry a gear blank, of a cutter having a se a Spring acting On Said plunger tending ries of blades movably mounted to carry to shift the same from the bottom of the Said blades in cutting across the face of a 15 notch toward the mouth thereof, and a sta gear blank so held, means for rotating said tionary retractor extending into said gear blank holder, means for shifting said groove, whereby it engages and pushes back cutter parallel to a line tangent to the base the plunger during the rotation of the disk, cylinder of the gear blank at the same speed 5 5 and permits the plunger to move outward as the linear travel of such base cylinder 20 after the same has passed the retractor. during the cutting action, and for returning 23. A geal cutting machine complising the cutter to starting position upon complet a gear blank holder, means for rotating the ing the face of a tooth of said blank, said same, a cutter having blades movable in a blades being arranged in a series of such ex 60 closed circuit for cutting, said cutter being tent that the entire series crosses the face of also shiftable in unison with the gear blank the gear in the time of cutting one tooth, for generating the tooth curves, means for there being a space between the beginning simultaneously rotating Said gear blank and ending of Such series permitting return and shifting said cutter back and forth, said of the cutter without interference with the cutter being provided with a blank por gear blank. 130 2. 1,516,524. 28. A gear generating and cutting ma of an interposed part of the gear and trav chine comprising means for Supporting and eling in paths which are equally distant continuously rotating a gear blank, a plu from one another at all points. - rality of rotatable cutting tools spaced apart 34. A gear. generating and cutting ina 5 to admit a tooth of the gear blank between chine comprising means for Supporting them and disposed with their cutting edges and rotating a gear blank, two coaxially parallel to One another to generate respec mounted milling cutte's with straight cut tively opposite tooth faces, and means for ting edges mounted to travel across the rim shifting said cutters bodily and parallel of the gear blank and, when so traveling, be O to their rotational axes in unison with the ing perpendicular to a plane tangent to the movement of the parts of the gear blank base cylinder of the gear blank, means for whereon they respectively act. shifting the cutters bodily in such plane and 29. A gear cutting machine as claimed in means for causing the linear movement of claim 28 in which the cutters are relatively the base cylinder of the gear to be equal to adjustable to regulate the width of the in said displacement. SI) cluded space between their respective cut 35. A gear cutting and generating Ina ting portions. chine comprising a cutter spindle, two cut 30. A machine as claimed in claim 28 in ter heads mounted on the same spindle and which said cutters include a cutter head having blades with cutting edges perpen fixed upon a spindle or shaft, a Second cut dicular to the axis of Said spindle, means ter head keyed upon said spindle with pro for supporting a gear blank with its rim vision for movement axially, a resilient crossing the paths of Said blades at right an thrusting device carried by the the latter gles thereto, the blades being disposed to cut head and bearing against the former head, opposite tooth faces of the gear blank and 2 5 and an adjustable abutment on the spindle being adjustable together and apart to de 90 against which the latter head is pressed by termine the width of the teeth bounded by Said thrusting means. . such faces, means for shifting Said spindle 31. A gear generating machine, as set and cutters axially, and means for rotating forth in claim 28, in which the said cutters the gear blank at a rate such that the linear 30 comprise one cutter head fixed upon a spin velocity of its base cylinder is equal to the 95 die or shaft, a second cutter head engaged velocity of such displacement. with said spindle in a manner permitting 36. In a gear generating and cutting ma axial movement but preventing relative ro chine, a cutter spindle, a bearing for the tating movement, an abutment on the spin same in which said spindle is movable ro dle at the side of the second cutter head tatably and endwise, a cutter head mounted OO more remote from the first cutter head, plun on the spindle having a toothed flange, and gers carried by One of Said cutter heads pro a driving pinion meshing with said flange jecting and movable toward the other head, for rotating the latter, said flange and pin and springs arranged to press said plunger's ion being arranged at their meshing parts 40 against said other head. parallel with the shaft and having a width 105 32. A gear generating and cutting mal of face sufficient to permit the described chine comprising a holder rotatably mount endwise movement of the shaft. ed and adapted to carry a gear blank, a cut 37. A gear generating and cutting ma ter spindle, two milling cutters mounted on chine comprising in combination with a ro 45 said spindle and spaced adjustably to cut tatable holder for the gear blank, a cutter O simultaneously tooth faces on opposite sides carriage, a cutter spindle mounted rotatably of an interposed part of the gear blank, on said carriage, a milling cutter on said spin means for imparting cutting rotation to said dle in position to act upon the gear blank, a cutters, means for rotating the gear blank, can fixed to the cutter spindle and hav 50 and means for shifting said cutters bodily ing an axially offset rib, roller abutments at a rate of speed equal to the linear velocity between which said rib projects and by the of the base cylinder and in directions such reaction of which against the rib in the that their generating points are displaced in course of rotation of the latter the cutter a line tangent to said base cylinder. and spindle are moved back and forth, and 55 33. A gear generating and cutting ma means for shifting said abutments in sub chine comprising means for supporting and stantially the directions of Said movement rotating a gear blank, a pair of milling cut of the spindle, to adjust the cutter for the ters having generating cutting edges mount location of cut in the gear blank. ed to travel across the face of the gear and 38. In a gear cutting machine a cutter 60 being perpendicular to a plane tangent to carriage, a cutter spindle mounted on said 25 the base cylinder of the gear, and means for carriage to rotate and with provision for displacing said cutter bodily in said plane moving endwise, means for adjusting said at a rate of speed equal to the linear velocity carriage transversely to said spindle, a cut of said base cylinder, said cutters being ar ter tool mounted on said spindle, and means 65 ranged to cut tooth faces on opposite sides for driving the tool comprising a gear ele 30 1,516,524 3. ment connected there with, a pinion mesh cut, an index worm wheel for rotating the ing with said element, the interengaging blank mounted on said spindle, a worm 40 teeth of the pinion and gear element being meshing with said index wheel and having Substantially parallel to the spindle, a shaft a shaft, means for driving said shaft, a 5 extending in Substantially the same direc bearing for the shaft in which the latter tion as the line of transverse movement of is held with prevention of end shake, and the cutter carriage, gearing transmitting means for adjusting said bearing endwise movement from Said shaft to said pinion, to set the gear blank into exact position. and a driver having splined engagement 41. A gear cutting machine as set forth with said shaft and mounted on a relatively in claim 40 in which a box or housing is immovable part of the machine. provided for said worm and said bearing 39. An adjustable gear generating and has threaded engagement in said housing 50 cutting machine comprising a rotatable spin whereby it may be adjusted by being ro dle for holding the gear blank to be cut, tated. 5 an index worm wheel mounted on said spin 42. In a gear cutting machine in combina dle, a worm meshing with said wheel, a tion with a rotatable spindle carrying the changeable gear connected with said worm, blank to be cut, a combined driving and in 5 5 a driving gear train including a transmis dexing means for said spindle, a worm sion gear adapted to mesh with said change wheel on said spindle, a worm meshing 20 able gear and a holder therefor movable with said wheel, a pinion connected to said to place said gear into mesh with substitute Worm, a gear meshing with said pinion, a changeable gears of different sizes, a mill shaft on which said gear is loosely mounted, 60 ing cutter having a cutting edge arranged a clutch for disengageably connecting said to travel in a path which intersects a plane gear to said shaft, a clutch shifter, a tim 25 perpendicular to the axis, and located be ing member controlling said clutch shifter tween the faces, of the gear blank, means to cause disengagement and re-engagement for shifting the generating point of said of the clutch, and synchronized driving 65 cutter in a path tangent to the base cylinder means for rotating said shaft and said tim of the gear blank and at the same linear ing member. 3.3 speed as such base circle, a carriage. On 43. A gear cutting machine according to which said cutter has its before mentioned claim 42 distinguished by the fact that said movements, and means for displacing said timing member is rotated at the same speed 70 carriage to adjust the cutter toward and as the index wheel, whereby indexing of away from the axis of the gear blank holder the blank is accomplished at each revolu 3. to accommodate gear blanks of different di tion of the latter. ameters. In testimony whereof I have affixed my 40. In a gear cutting machine a rotatable signature. spindle for holding the gear blank to be EDWIN R. FELLOWS,