US2038665A - Gear grinding machine - Google Patents

Description

April 28, 1936. E W. WLLER j 2,038,665

GEAR GRINDING MACHI NE Filed March 1, 1932. 4 7 Sheets-Sheet 1 April 28, 1936. E. w. MILLER GEAR GRINDING MACHINE "Filed March 1, .1952

7. sheets-Sheet .s

E. w. MILLER GEAR GRINDING MACHINE Filed March l,- 1932 April 28,1936;

Apr-il 28, 1936.

E. w. MILLER GEAR @BINDING MACHINE Filed March l, 1932 '7 Sheets-Sheet 4 NN NNN a. N.

April 28, 1936- y E. W. MILLER 2,038,665

v GEAR GRINDING MACHINE Filed March 1, 1952 7 sheets-sheet 5l l/ll/ @wfffw'wr y 7 Sheets-Sheet 6 April 28, 1936. E. w. MILLER l GEAR GRINDING MACHINE Filed March l, 1952 E. w. MILLER GEAR GRINDING MACHINE l Ap 2s, 1936.

7 sheets-sheet '7 Filed March l, 1952 Patented Apr. 28, 1936 l UNITED STATES PATENT OFFICE 2,038,665 GEAR GRINDING MACHINE Applicationr March 1, 1932, Serial No. 596,003

21 Claims.

'I'he present invention relates to the art of grinding the tooth faces of gears. Its primary object and accomplishment is to enable gears to be ground to completed condition, that is, nished as to all of their teeth, more rapidly than heretofore. Other objects, related to the foregoing, are to enable successive teeth of the gears to be ground in the course of a continuous traverse of the gear in a circular orbit, without reversal of direction andv to index the gear in the course of each revolution; to produce a Wider zone of contact between the grinding wheel and the work than has been known heretofore in grinding by the generating process; and to vary the speed of revolution of the work in its orbit whereby to give a relatively slow traverse of the work while grinding ,takes place and a more rapid traverse during idle periods. ject is to maintain the wheel in correct and true form and position for the performance of accurate grinding at all times. Still another object is to accomplish the true and accurate grinding of wide faced gears in a succession of traverses past the grinding wheel in neighboring paths, with obliteration of any ridges between the cuts made by the wheel in such successive traverse.

Further objects, uthe means by which they are accomplished, and the essential Ycharacteristics of the invention'- can best be set forthin connection with a detailed description of specific mechanism containing an embodiment of the invention. In the following speciflcation is given such a description of a specific machine and of certain alternative constructions for some of the parts of the machine.

In the drawings which illustrate the machine and its modifications thus described,-

Figul is a side elevation partly broken away to show interior parts; I 1

Fig. 2 is a front elevation;

Fig. 3 is a plan view;

Fig. 4 is a longitudinal vertical section taken on line 4-4 of Fig. 5;

Figs. 4a and 4b are detail sectional and eleva- Still another obtional views of one of the controlling gears, show- Fig. 10 is a similar view showing another modified form of work holder;

- Fig. 11 is'a similar view showing still another work holding and operating means;

Fig. 12 is a cross section on line I2I2 of Fig. 11. 5

Like reference characters designate the same parts wherever they occur in all the figures.

The detailed description which follows of the specific machine and its modifications thus illustrated is for the purpose of explaining the generic 10 characteristics ofthe invention with respect to a concrete example.. but is without intent to limit the scope of protection here sought to such speciiic machine otherwise than as Vmay be required by the prior art and the purport of the appended 15 claims; my intention being to protect the invenl tion, by such description and claims, not only specically butalso generically in the full scope. of its essential novelty and with the 'benet of all equivalents. 20

The base or frame of the machine thus illustrated comprises a boxlike casting I5 having a semi-cylindrical horizontal bearing I6 in its upper part wherein a work carrying turret I'I is rotatably mounted, and a vertical cylindrical 25 bearing I8 at the forward end of its lower part wherein the grinding wheel holder and wheel truing mechanism are mounted. The turret I1 is cylindrical -externally with two or more zones, preferably at its opposite ends, separated from one another by an intermediate annular space, tting complementa] internal surfaces of the bearing I6, and has a flange I9 at one end and a retaining disk 20 at the other end to withhold it 35 from end motion. Itis removably secured in the bearing by a semi-cylindrical cap or cover 2| which surrounds its upper half and is secured to the base by bolts 22. Flange I9 and plate 20 overlap the ends of this cap andthe bearing. 40 Three work spindles 23 are mounted rotatably in suitable bearings 2l in the turret, quidistant from, and equiangularly spaced about, the axis of the latter. Preferably there are twobearings fo'r each spindle, alined with one another in op- 45 posite end portions of the turret; the intermediate part of the turret having interior open spaces between the bearings whichopen into the previously mentioned annular space. This number of spindles is not an essential detail, for there may be four or more spindles, or two, or one only for certain purposes; but it is a convenient number. Work arbors 25 are secured in the several spindles by any suitable means and carry gears 26 to be ground. 55

l' the cap 2 i. This internal gear is coaxial with and surrounds the turret; and the turret is formed with recesses which contain the master gears 21 and permit their protrusion into mesh with the internal gear. The internal gear is wider (longer .end of the other.

in the axial direction) than the master gears 21 in order to permit axial movement of the spindles asand for a purpose later described. A device for eliminating backlash between the control gears is shown in this connection, on an enlarged scale, in Figs. 4a and 4b; being omitted from the assembly drawings, bec'ause of the small scale of thelatter. It consists in making the master gears 21 .each in two parts, 2li and 212, of equal length axially and exactly alike as to the number, pitch and form of their teeth, inl tandemarrangement on the work spindle. One of these parts, as 21|,

is keyed to the spindle andhas an axial centering n extension 213 entering `.a cavity in the adjacent Afclamping screw 214i lpasses throughl an arcuate hole 215 in one of the gear parts, as 212, into -a tapped hole in the other, or there may be a number of such clamp screws, for binding the parts together; and an adjusting screw 2 16is threaded into one of the parts, as 212, and has an eccentric pin or finger 211 contained in a radial slot in the other for effecting easily and accurately such angular displacement between the parts as Ywill bring their teeth into firm bearing on opposite sides simultaneously with the teeth ofthe controlgear 2Q.

The turret. is provided with a surrounding seriesof external gear teeth 29 whereby it may be rotated by power delivered from a motor 30, pulley and belt, or sprocket and chain drive 3l, 32, 33, shaft 35, gear train 35, 36, 31, shaft 38, worm or helical gear 39, Worml wheel or helical gear lill, gear 4l connected with Ml, and an idle gear d2 in mesh with 4| and the teeth 29 of the turret. Pulley 33 and gear 35 are both made rast on shaft 34; gears 3.1 and 39 are both made fast to shaft 38, and the intermediate gear 36 is secured to a shaft 43; these shafts being mounted parallel to one another in suitable bearings in the interior of the frame. As the turret rotates itrevolves the work spindles in a planetary manner, and' the master gears on such spindles, rolling on the stationary internal gear 28, rotate the spindles about their respective axes.

The grinding Wheel 44 has grinding zones 45 at opposite sides of its rim formed in prole identical with the tooth of an internal gear conjugate to. the gears to be ground. Ordinarily the master gears 21 are identical, not only in pitch circumference, but also in number and form of teeth with the gears to be ground. Consequently the wheel profile in such cases is identical with a tooth of the internal control gear 28, and is located with its Work-engaging proiile on the same pitch cylinder as the teeth of the internal gear, as shown best in Fig. 6. To define this relationship more exactly in words, the grinding wheel is located radial to the axis of the internal gear and entirely outside of the circumference of such gear except as to the limb or portion which passes between the teeth of the gears to be ground, and this portion is at the same distance from. the center, and has the same dimensions in radial sec-v tion, and the same pressure angle, as a tooth of the control gear. Necessarily the grinding wheel is set off to one side of the control gear far enough to act upon the work.- piece' carried beyond the end of the spindle.

The position of the grinding wheel shown in the drawings is designed for grinding straight spur gears. But it will be obvious to those skilled in the art that the wheel may be adjusted angularly for grinding helical gears. When so adjusted, however, the part of its rim nearest to the work still corresponds to the tooth of an internal gear with which thev gear being ground is adapted to mesh.

'I'he Work gears are positioned on their arbors so that their teeth are alined with the teeth of their respective master gears, with the aid of a work setting attachment shown in Figs. 2 and 3. This attachment comprises a bracket ld mounted on a rod l1 which projects forwardly from one side of the turret bearing i6. A spring pressed plunger rod 48 is slidable endwise in the bracket and has a centering cone dil on its end next to the orbitof the work pieces. The bracket is clamped adjustably on rod d1 and is of suitable design to bring the centering point radial to the turret axis and in axial alinement with one of the teeth of the control gear. Normally it is held back out of the way of the work by-a cross pin 5B on the plunger overlapping the outer end oi the bracket guideway, Vbut when turned so as to allow this cross pin to register with a notch 5l in the guide, the centering pin is advanced by its spring to enter the adjacent tooth space of the work piece.

'I'he grinding wheel is carried by the shaft of a motor 52 (Fig. 2) which is secured to, and may be radially adjustable on, a sleeve 53, called the grinding wheel stool, which ts slidingly in the bearing i8. Being in the position described and being rotated at high speed by 'themoton the grinding wheel is adapted to generate and cut to finished size the sides of two adjacent teeth in,

the work piece as it is carried past by the rotation of the turret. The several work pieces are 'thus carried past the grinding wheel in succession, and are caused by the control gear to roll in passing as though in mesh with a stationary internal gear of which the rim of the grinding wheel is one tooth.

lt is to be noted that the number of teeth in the control gear 28 is a prime number, or at least is not a multiple of the number of teeth in any master gear, wherefore the work pieces make more, or less, than a complete rotation, or more or less than a whole number of rotations, about their respective axes `in each revolution of the turret. Thereby different teeth of the Work are presented to the grinding wheel with each revolution. As a work indexing mechanism this device appears to reach the ultimate limit of simplicity, and it is wholly efcient. In a number of revolutions of the turret equal to the number of teeth on any one of the work pieces (or a multiple of this number in the case of a wide faced gear ground in a number of traverses, three gears are completed.

I have made provision for a variable speed of revolution of the turret, so that while each work piece is actually being ground, its traversing motion will be slow enough for efficient grinding and to avoid danger of breaking the abrasive wheel or overheating cr otherwise injuring the work; and the turret will be sneeded un during non-grinding periods. With three spindles, the work pieces are in actual engagement, with the grinding wheel during a minor fraction only of the revolution of the turret. To effect such variable speed. the gears 35, 36 and 31 are made as elliptical gears which, in the specific illustration, give an angular speed ratio of shaft 34 to 38 of 1 to 9, when the gears are in the position shown in Fig. 1, and of 9 to 1 when turned through 180 and the angular speed ratio between the turret and the gear 39 is 1 to 3. 'I'he acceleration is accomplished by this means with a close approach to harmonic motion.

In case the work pieces are of suchwidth in proportion to the diameter of 'the grinding wheel that they cannot be finished with accuracy in all parts of their width in a single pass, they should be carried past the grinding wheel a number of times with an increment of axial feed between traverses. I have provided for such an axial feed by making the spindles 23 movable endwise through their bearings in the turret and by making the internal control gear wider than the master gears. The several spindles are connected by means of a coupling 54 with a slide 55, reciprocatable in a guideway 56 ofthe machine frame in the axial direction of thespindles. Such slide is conveniently made as a sleeve surrounding a guide rod 51, coaxial with the turret, having an extension 58 slidablyv contained in a bearing 59 in the turret. It is confined on the rod between a shoulder 60 and a nut 6|. Conveniently the coupling 54 is composed of two disks detachably bolted together, having openings in which the several spindles and the guide rod are contained, and further constructed to hold and grip anti-friction thrust bearings 52 and 53 which surround the work spindles and the 'guide rod respectively. A separate retainer 54 for the latter thrust bearing is detachably bolted to the outer plate of the coupling. These last described details, however, are optional features which may be varied without departure from the essential invention.

The slide 55, which may be called for convenient definition the spindle reciprocator, is fitted non-rotatably in its guideway and is provided on its under side with rackteeth`55 in mesh with a gear segment 66 carried by a lever 61. 'I'his lever is pivoted on a cross shaft 68 and connected 4by a link 69 with an intermediate lever 10 pivoted at 1|. The intermediate lever in turn is coupled by a connecting rod 12 with a crank pin 13 carried byva disk 14 and adjustable radially thereof in a known manner by a screw 15. Crank disk 14 is carried by a shaft 16 driven through change gears 11, 18 and reduction gearing 19, 89, by a motor 8|. Bysuitable adjustment of the crank Din, and .correlation of its speed with that of the turret, work pieces of any/width may be fed axially across the highest part of the grinding wheel in the course of any desired number of revolutions of the work. For illustratio1 1,`if the work vpieces are gears of 30 teeth and of such width that tation of the crank occurs'in the opposite directionv while new work pieces are being ground. The

axial feed movement so accomplished takes place continuously giving a minute increment I after each tooth of the work has passed the grinding whee1, but advancing the work through the prescribed fraction of its width between successive grinding traverses of the same tooth.

'In order to avoid leaving any ridges, however minute, between the zones ground in successive traverses, I have provided means for superposing a rapid back and forth reciprocation of the spindles upon their continuous feed motion; `This motion ls effected by making the pivot 1| of the rocker4 lever -1I) as an eccentric projection on a 'rotatable shaft 82, and rotating said shaft at the desired speed by a motor 83 through a belt and pulley (or sprocket and chain) drive 84, 85, i6. The eccentric motion of pivot 1| oscillates rock lever 10 additionally about its connecting pivot 81 withv the connecting rod 12 as a fulcrum. The secondary reciprocation thereby applied to the spindles is preferably about equal to (but may be somewhat greater or less than) the length of the continuous axial feed between successive grinding traverses of the same tooth of the work piece.'

Occurring many times while any given tooth of the work is rolling slowly pastv the rapidly rotating grinding wheel, it causes the work to be finished uniformly.

For the grinding of helical gears with the use of the feed motion last described, the spindle controlling gears (by which I mean the stationary internal gear 28 and the master gear 21 on the spindle) are likewise made as helical gears with the same helix angle or lead as the work piece; whereby they give the necessary twisting or screwing motion to the work.

Although the generating principle described requires that the control gears have a certain relationship, as explained, to the work, this does.

not mean that one machineis necessarily limited to nishing gears of only one diameter, pitch, and form of tooth. On the contrary, the machine may be prepared for finishing a wide variety of different gears by removing the turret with its work spindles and control gears, and substituting a different turret. 'I'his is permitted readily by removing the cap 2| of the turret bearing and the -detachable cover of the guideway which contains the spindle reciprocator 55. 'I'he spindle recipro- 'eating means, being coupled with the spindles, is

a part of the turret unit. 'I'helarge internal control gear, although associated with this unit, is independent of it and may be separately and accurately located in the bearing independently of the turret. Hence the turret retaining ange 20 is made as a separate plate and the diameter of the turret at the end adjacent thereto, the outside diameter of the teeth 29, and the coupling 54, are all made smaller than the internal diameter of the gear 28 for withdrawal and insertion endwise through the latter; and the bearing and its cap have positioning shoulders 88 for this gear.

A prime essential for the successful operation of the machine is the maintenance of the active or operating faces of the grinding wheel in true form and correct position. One phase of this invention comprises means for truing the wheel to the desired form and means for adjusting the wheel and truing means as to position. Attention is directed to Figs. 4, 6 and 'I for explanation of these features. Truing diamonds 89 for the two faces of the grinding wheel are set in the inner ends of screw threaded holders 90, which may be of known character` mounted and adjustable in a known way in carrier slides 9|. Such carrier slides are independent of one another and are pressed apart 4by springs 92 interposed between them, which springs press and hold external abutternal control gear and they are located so that all positions of the carrier slides are parallel to one another. 'I'he diamonds are located and movable in an axial plane of the grinding wheel, but

at the opposite side of the grinding wheel axis from the work.

The templets or formers are set transversely in cylindrical holders bars 91, 91, which bars in turn are set into complemental sockets in a main holder 98 which fits the interior of the grinding wheel stool 53. The main holder is made of two parts separated from one another on a median plane,

- and fastened together detachably by bolts 99.

Guideways I 00 are provided in each of the halves of this holder leading inward from the cleavage plane, in which the carrier slides for the diamonds are contained and into which the cam ends of the .formers project. A spring 0| is connected to each carrier slide, being coupled at one end to a pin |02 on the slide and at the other end to a pin |03 set into thermain'holderacross the carrier guideway. These springs normally withdraw the diamonds outside of the circumference of the wheel. The carrier slides rest on the upper end of a plunger I 04 which passes through, and is movable endwise in, guides |05, and bears at its lower end on the. short arm |06 of a treadle lever |01. The operator, by pressing on the treadle the concave zone of the wheel.

and releasing it, may thus at will traverse the truing diamonds across the faces of .the'grinding wheel. The springs |0| previously Ymentioned hold the carrier slides against the plunger and insure withdrawal of 4the diamonds beyond 'the rim of the grinding wheel when the pedal is released.

One or both of the formers Afor each of the carrier slides may be adjusted for minor correction of the path in which the truing diamond travels. In the illustration the upper abutment, 95, of each pair is thus adjustable, although it is to be understood that the abutment 96, or both of them, may be, as well. As here shown, a cylindrical step 95| is set crosswise in the` bottom of the slot in the holder bar 91 which receives the former 95,

the latter being notched in its under edge to bear on said step. Two adjustable screws 952 and 953 are set in the end of the bar to bear on the upper edge jf-theo former at respectively opposite sides of a line passing through the step from edge to edge ofthe former. By withdrawing either of the screws and setting.up the other, the former may be tilted about its step bearing through a small angle so as to shift the inclination of its guiding face, as needed to correct or modify, within limits, the curvaturelgiven by the diamond to To state in words a generic characteristic of the truing of which one embodiment is shown in the drawings, it maybe remarked that `the formers'of each pair 'are set in a tandein arrangement. lengthwise of the adjacent carrier slide, or of the directions in which such slide is moved in truingthe wheel; and that the guiding faces of the two formers of a pair are on relatively the same ends of the formers and .divergein relamove and transverse alsol to the wheel.

'ditional increment of motion.

ables them to tively the same directions from a straight line tangent to the guiding faces, or equally, a straight line joining the two coacting abutments of the carrier slide. The distance apart of corresponding formers'for the two slides is related 'to the width of the slides in such manner that the two diamonds 89, 89 face each other across an intermediate space in an alinement transverse to the paths in which the diamonds are constrained to 'I'he distance apart of the diamonds and their proper relationship toa radial plane of the turret is of course determined by adjusting the screw threaded holders 90 in the carrier slides.

A third diamond |08, for facing oir' the circmpensate fordiminution of -its diameter caused by truing; and the truing tools are adjustable in the same direction and through twicev the distance and the change in position of the wheel. To make these adjustments the grinding wheel stool is movable axially in the bearing I8 and is restrained from rotation by a key It rests on an anti-friction thrust or step bearing ||2 which in turn rests on a screw ||3 threaded through a nut ||4 secured to the bottom of the bearing. The screw is connected at one end to, o r formed as, agear I5 in mesh with a worm or helical` gear I|6 on a shaft ||1 which projects to the outside of the base and is adapted to be rotated by any suitable means, manual or automatic. ,.The main holder 98 for the truing tools is in turn slidable endwise in the stool, in which it is restrained from rotation by a key ||9. It rests on an anti-friction step or thrust bearing |20 which in turn rests on a screw |2| threaded intoa nut |22, suitably secured t, or made as an integral part of, the steel 5 3. The screw |2| is coaxial with screw H3 and has an extension slidingly fitted within the latter and restrained from rotation therein by a spline or feather |23.

It will-now be apparent that rotation of the screw ||3 moves the grinding wheel stool bodily with all that is contained`therein or thereon, and the simultaneous .rotation of screw 2 moves the truing tool main carrier with an adscrews, |3 and 2| have different diameters, the lead of their threads is the same, wherefore the truing tools are shifted twice as far as the wheel in making any adjustment, as is needed to compensate for-both the reduced diameter and the altered position of the wheel. Or, considered from a different point of View, the truing attachment is adjustable relatively to the grinding wheel and with the grinding wlje/l'holder. The

the same absolute direction, ene performed at one time by a justments are i specific arrangent here` shown, where both ad- I single means.

The previously mentioned adjustment of the grinding wheel for grinding helical gears, may

'Although the to compensate for both the reduced diameter be accomplished by turning the entire stool in its bearing, wherefore the spline or key for vthe stool may be set in a head |24 which is supported rotatably on the bearing |8, and by rotatation of which the angular setting of the wheel may be accomplished. Any suitable means, of a character already known or which may hereafter be developed, may be used for measuring or indicating the angle of adjustment of the head |24, for locking it when adjusted, and for measuring or indicating the adjustments of the wheel for diameter and penetration across the orbit of the outer side of the work pieces. Such means are indicated in the drawings, but as they involve in detail nothing new with the present invention, they are passed over Without 'specific description.

It will be understood that a further adjustment may be provided for positioning the wheel to grind other gear elements oi the unit assemblage shown in Figs. 1, I3 and 4, as well as the element 26. Such an adjustment may be provided for by making the bearing i8 separate from the base structure l5 as a part of, or mounted on, a carriage adjustable on guideways parallel to the work spindles, and equipped with a screw, or a rack and pinion, or other mechanism for setting it in position, and with means for securing it in position. Suitable designs for such carriage, adjusting means and securingmeans will be apparent to the mechanical draftsman trained in the design of machine tools, from the foregoing description, without need of further illustration in these drawings.

Meansv for ooding the work and grinding wheel with a cooling fluid may also be provided, and applied by the machine designer according to well known and commonly used practices, without need of instruction by this specification.

A machine embodying the principles hereinbefore described is capable of turning out work finished to a high degree of precision and a ccuracy, with great rapidity. The formation of the grinding wheel with the profile of an internal gear tooth affords in principle the maximum width of grinding engagement and conduces to smoothness and continuity of the surface generated by the rolling traverse of the work. The continuous rotation of the work always inA the same direction in a circular orbit avoids the lost motion, lost time, and high expenditure of power incident to the operation of a reciprocating or vibrating work holder. This characteristic, together with the variable speed i'actor, which slows down the work during the fraction of its travel while it is engaged with the grinding wheel, enables the rotation of the turret to be performed at a relatively high speed in terms of revolutions pe'r minute. For instance, it is feasible to rotate the tu rret at as high a speed as 40 revolutions per minute. 'If we assume that there are three work pieces of 30 teeth each in course of grinding and that the teeth of these gears have a length requiring four traverses of each past the wheel, then all three will be nished inthe course of 120 rotations of the turret, taking place in three minutes; that is, an average of one minute for each gear. In the case of Aa narrower gear or with a grinding wheel of larger diameter, the work may be completed with fewer traverses of each tooth; while the turret may be made with provisions for carrying more than three Work piecesj or a higher speed of the turret than 40 revolutions per minute may be attained, all of which factors conduce to a still more rapid output.

Changes in detail may be made inthe machine for various purposes. For instance, the one shown in Fig. 9 is designed to accommodate a gear |28 made integral with a solid shank |21 which cannot'be applied to a spindle and arbor of the type shown in Fig. 4. The spindle 23a is made with an enlarged tubular vend in which is secured detachably a chuck |28 adapted to receive the' shank and grasp the hub portion of the gear. This same gure shows also a varlation in the structure of the turret which, instead of ybeing made virtually as a single solid piece, is

. there is room for only one work spindle. Such spindle, shown as being like the spindle 23 in Fig. 4, (but which may be like that shown in Fig. 9, or of other design), is mounted eccentrically in the turret, and its eccentricity is such as will prmit running of a master gear 21a in mesh with the internal control gear 28h. 'Otherwise the turret and the means for reciprocating the spindle may be like those previously described, or of any other suitable design.

Figs. l1 and 12 show adesign of turret adapted to generate helical gears hy the aid of straight spur controlling gears; and also provisions for minimizing any possible errors in the internal control gear. In this design the master gears 21h are withheld from reciprocation with the work spindles by thrust bearings |30 at eitherside on the turret and in thel bore of each a helical guide sleeve |3| is made fast. Complemental guide members |32 and |33 are secured to the spindle.l These guides are of essentially the same character as those shown in the Fellows Patent 1,662,109, March 13, 1928, and may be made with either straight or helical contact edges, the latter giving a. rotary movement to the spindle about its axis as it is moved endwise. As the external master gear is in this case larger than the gear being ground, a compensatory rotation is given to the internal control gear 28c so that the work piece will roll in correct mesh with the imaginary internal gear of which the grinding wheel proiile forms one tooth. Such compensatory or diier.- ential rotation is. given by providing an external series of gear teeth |34 on the control gear and interposing between these teeth and the gear 42a (which corresponds with the gear 42 shown in Fig. 4) a change gear train |35, |36, |31, of which the last named gear meshes with theexternal teeth |34. Gear |35 is fast on a shaft |38?! imize any errors which may exist in the spacing and form of the control gears. This latter feature may be used without as well as with lthe provision of helical guides for the work spindle. That is, it may be applied to the design of Fig. 4

which has no such helical guides, In other rescope of the invention, but without setting any limit to such range. Many other changes and variations in the same and other parts of the machine may be made, all within the protection which I claim.

I have described a plurality of electric motors as the prime movers for various parts of the machine, and for rotating the grinding wheel. All of them except the one which drives the grinding wheel are equipped with their own speed reducing gear trains which enable them to deliver motion at moderate speeds suitable for the requirements of the machine. but as they are commercial articles and involve no invention original' with me, I have not attempted to illustrate them in detail. It is to be understood also that motion may be derived by belts or other means from prime movers of other types for operating the machine.

What I claim and desire to secure by Letters Patent is:

1. In a grinding machine, a rotatable and axially movable work spindle, a grinding wheel in position to act upon a work piece mounted on said spindle, and mechanism for shifting the spindle axially with a motion compounded of relatively rapid reciprocations and a relatively slow continuous travel in the same direction.

2. In a grinding machine having an endwise movablev work spindle, mechanism for shitting said spindle endwise including a lever, motion transmitting means movable .progressively in the same direction applied to 'a part of said lever, and reciprocation transmitting connections applied to a diil'erent part of said lever, whereby to advance the spindle with a compound movement of reciprocation and continuous advance.

3. In a lgrinding machine having a relatively movable grinding wheel and work spindle, of which one of such movements is the cutting travel of the wheel, another is a rolling generative movement between the work spindle and wheel, and a third is a relative traverse longitudinally of the spindle axis, means for effecting such traverse with a compound motion of reciprocation and progress, comprising mechanism including a lever, a progressively acting motion transmitter connected to one part of said lever, and a vibrating motion transmitter connected to another part of said lever.

4. Ina grinding machine having a relatively movable grinding wheel and work spindle, of which oneof such movements is the cutting travel of the wheel, another is a rolling generative movement between the work spindle and wheel, and a third is a relative traverse longitudinally of the spindle axis, means for eiIecting such' traverse with a compound motion of reciprocation and progress, comprising mechanism including a lever, a fulcrum for said lever mounted to revolve about an eccentric axis, means for so rotating said fulcrum, and a motion transmittermovable in one direction and coupled to the lever at one side of the fulcrum.

5. A gear grinding machine comprising a base having a bearing, a turret revolubly mounted in to the orbit of said Work spindle, but wholly external to such orbit and arranged with its limb which is nearest to such orbit in the position of a tooth of an imaginary internal gear meshing with a work piece carried by the work spindle.

6. In a gear nishing machine of the character set forth, a stationary base having a semi-cylindrical turret-receiving cavity and a detachable cap concave internally in complement to the cavity of the base, a turret having bearing zones adjacent to its ends iltting within the cavities of the base and cap, an internal gear surrounding the turret and secured coaxialiy therewith between the base and cap, a work spindle supported rotatably in the end portions of the turret at one side of the axis of the turret, a gear on said spindie in planetary mesh with said internal gear, and means for rotating the turret.-

7. In a gear iinishing machine of the character set forth, a stationary base having a semi-cylindrical turret-receiving cavity and a detachable cap concave internally in complement to the cavity of the base, a turret having bearing zones adjacent to its ends fitting within the cavities of the base and cap, an internal gear surrounding the turret and secured coaxialiy therewith between the base and cap, a work spindle supported rotatably in the end portions of the turret at one side of the axis of the turret, said spindle being also movable endwise in its supporting bearings, a gear secured to the spindle between the supporting bearings thereof in planetary mesh with the internal gear, means for rotating the turret,

and means for moving the spindle endwise relatively to the turret.

8. In a gear finishing machine, a base, a turret rotatably mounted in the base, a work spindle rotatable and movable endwise in the turret at one side of the rotational axis ofthe turret, a slide external to the turret in line with the axis thereof, a thrust coupling between the slide and Aspindle connected rotatably with each, means for moving the slide in line with the axis o f the turret, means for simultaneously rotating the turret, and

a gear on the spindle in planetary mesh with said r internal gear.

9. In a gear finishing machine, a stationary support, a turret rotatably mounted in said support, Work spindles mounted in said turret on axes eccentric and parallel to the axis of the turret, and being movable endwise relatively to the turret, a slide mounted in line with the axis of the turret and having a guiding extension projecting into the turret, means for moving said slide endwise, a coupling having rotatable and thrust-transmitting connection with the slide and spindles respectively, means for rotating the turret, master gears carried by the spindles, and a sun gear mounted on the base coaxialiy with the turret in mesh with said master gears.

10.- In a gear finishing machine, a base, a turret rotatably mounted in said base, a grinding wheel formed in profile at its rim like the tooth of a gear, a sun gear mounted on the base coaxial with the turret, a work spindle rotatable in the turret on an axis at one side of the turret axis, a gear on said spindle in planetary mesh with the sun gear, means for rotating the turret, and means for rotating the sun gear with such speed. and in such direction as to impart t0 a work piece secured to the spindle and of diierent diameter than said planetary gear, the same motion as would be imparted to the work piece by rolling it in mesh with a sun gear of different diameter than the aforesaid sun gear.

Il. 1'n a gear finishing machine, a base, a turret rotatably mounted in said base, a sun gear mounted on the base coaxial with the turret, a work spindle rotatable in the turret on an axis at one side of the-turret axis, adapted to carry a gear to be finished, a master gear on the spindle of larger diameter than the gear to be finished, in mesh with the sun gear, means for rotating the turret, and means for rotating the sun gear at such different angular velocity than that of the turret as to give the spindle an increment of rotation about its own axis sufficient to rotate the gear to be finished in the same manner as though rolling in mesh with a stationary sun gear.

12. In a. gear finishing machine, a rotatable turret, a work spindle mounted in said turret on an axis parallel to and at one side of the turret axis, a master gear surrounding said spindle, a sun gear coaxial with the turret in mesh with the master gear, the spindle being movable endwise as well as rotatable, means for rotating the turret, means for moving the spindle endwise independently of the turret and master gear, and guiding means on the spindle and master gear respectively having contacting guide faces extending longitudinally of the spindle and'adapted to be of contours such as to give incremental rotation to the spindle consequent upon its endwise relative motion.

13. In a gear finishing machine, a base, a turret rotatably mounted in the base, a plurality of work spindles rotatably mounted in the turret on axes beside and parallelr to the turret axis, said spindles being also movable endwise relatively to the turret, an internal gearI surrounding the turret coaxially, a master gear on each spindle in mesh with said internal gear, and confined against endwise movement relatively to the turret, each master gear and its spindle having complemental guiding means with contact surfaces extending longitudinally of the respective spin# dles, means for rotating the turret, and means for moving the spindles simultaneously endwise.

14. In a gear nishing machine as set forth in claim 13, the said internal gear being rotatable independently of the turret, and means for rotating said internal gear simultaneously with the rotation of the turret but at a dierent angular velocity. f

15. In a gear finishing machine having means for effecting a relative motion of generation between a gear to be nished and a rotating 'nishing tool, means for effecting a relative progression in the axial direction of the work, between such tool and the gear being finished, in the course of a number of traverses of the work past the tool,

and means for imposing a rapid reciprocating movement upon the member which is so shifted.-

ing wheel in position to act on a work piece mounted on said work holder, one of said holders being movable relatively to the other in a direction such as to transfer the grinding effect progressively along the work piece carried by the work holder, a lever connected with said movable holder for so propelling it, motion transmitting means movable progressively in one direction applied to a part of said lever, and reciprocation transmitting connections applied to a different part of said lever, adapted to move said part repeatedly in opposite directions while the first named part of the lever is moved continuously in vone direction.

18. In a grinding machine having means for eifecting a relative rolling motion of generation d work axis in the course of a number of traverses past the grinding Wheel, whereby to distribute the grinding effect lengthwise over the teeth of the work.

19. In a gear nishirg machine, a turret and spindle combination comprising a cylindrical turret having external bearing surfaces, spindles having rotatable bearing engagement in the turret on axes eccentric and parallel to the axis of the turret, master gears on the respective spindles intermediate the ends thereof, the turret having open interior spaces containing said master gears' and from whichrthe outer limbs of the master gears protrude, said spindles being movable endwise in the turret andprotruding at one end therefrom, a rod slidingly mounted in the axial line Iof the turret, a coupling rotatably mounted on said rod and having rotatable and thrusttransmitting connection with the several spindles, and a propeller connected with the rod for transmission of endwise movement thereto.

20. A gear grinding machine comprising a grinding wheel lhaving a prole the same as that of a gear tooth conjugate to the gear to be ground, means for carrying a gear to be ground in an orbit so located that a point in the toothed zone of such gear intersects the rim of the grinding cations to the gear in the course of its traverse i l past the grinding wheel.

21. A- gear finishing machine comprising a supporting structure, a turret rotatably mounted thereon, a. work spindle rotatably mounted in the turret at one side of the axis of rotation of the turret, adapted to revolve in an orbit a gear tdv be finished, a grinding wheel mounted in a positon substantially radial to suchmorbit so that its rim may enter an interdental space'of the work gear in each traverse of the latter past the wheel, a sun gear mounted on the supporting structure coaxial ,jwith the turret and rotatable about such axis,- a master gear on the work spindle in mesh with said sun gear, and means for rotating the sun gear in such direction and at such speed as to cause a work gear smallerA than the master gear to make rolling .engagement with the rim of the grinding wheel as with the tooth of a stationary sun gear.v

EDWARD W. MILLER.

Images