US1338320A

US1338320A - Cutter-grinding machine

Info

Publication number: US1338320A
Authority: US
Publication date: 1920-04-27
Anticipated expiration: 1937-04-27

Description

F. MULLER.

CUTTER GRINDING MACHINE.

APPLICATION HLED S|IPT.I3.1918.

m L R w B mm m m pH W w h F,

F. MULLER. CUTTER GRINDING MACHINE. APPLICATION FILD SEPT. I3. I918.

1,338,320. Patented Apr. 27, 1920.

J 2 4$HEET$-$HEET Z- Q 0 g 0 If 0 0 9/ lNVENTOR.

TTORNEY F. MULLER.

CUTTER GIHNDING MACHINE.

APPLICATION HLED SEPT. I3. I918.

1,338,320, Patented Apr. 27, 1920'.

4 $llEET5'-SIIEET 3- INVENTOR. FM M BY J. 7

A TTORNEY F. MULLER. CUTTER GRINDING MACHINE. APPLICATION men SEPT. I3, ms.

Patented Apr. 27,1920.

Ji /I UNITED STATES PATENT OFFICE.

FRIEDEBIOH MULLER OF HARTFORD, GONNEOTIGUT, ASSIGHOB '10 PRATT & COMPANY, OF NEW YORK, N. Y., A COLPORATION OF NEW JERSEY.

CUTTER-GRINDING MACHINi l Specification of Letters Patent. Patented A i )1. 7,

- Application filed September 13, 1918. Serial No. 258,871;

7 i) all whom it may concern Be it known that I, Fnmnnmcn Mt'iLLnn, a citizen of the United States residing at Hartford. 1 the county of State of Connecticut, have invented certain new and useful Improvements in" Cutter- (irinding Machines, of which the following is a specification.

A machine embodying the invention is particularly adapted for grinding the front "radial or approximately radial faces. of

provide an lint 5 i wheel hayingneonicalignndl mil1ing cutters and other analogous fto'ols such as; taps and: reainers. :ll e machine is pl'inu rilyintended for the grind ng of out! ters having teeth;

limitedto. all

, htnsssam is a l. adyit'ed-for i wi i twa ps c t r L straight; ng fa es thecutt max. used'fmfig'rin (inc -of-th faces. "The' ciittliflat? be groundicanthaij either plane or he icoidal cutting faees,-and

in either case thoimaohine can be readily. ad-

justed to accommodate cutters 19f different diameters without interfering with the correct operative 5 relationship between Ethe grinding wheel sand the cutters. another. object of thein'vention is to-prov1de im-.

proved means %for iholding wa'ndzgturning; the, cutters and fori; effecting adj ustments' to, conform to cutters .having difierent degrees of inclination. Milka-further object.of ;,the invention is to provide a wheel ressing mach-l anism having aa'novcl relationship to the wheel and tothe other parts of,.the machine which enables the whee to bedressed with out changingthe" effective grindmgposltion thereof. F urther objects of rtheltmventlon are to secure certain improved-featuresof construction and arrangement of parts which willbefully-apparent from the following' specification and claims. v

In the accompanying drawings I have shown the embodiment of the invention which is now deemed )referable, but it will be understood that the drawings, are for illustrative purposes only and are not to be construed as defining or limiting the scope Iiartford ,and

Yith inclined or helicoidalfront cutting facesthut vthe, nnijphineasnot.

on the front cutting faces of a machine eni- .ent from that indicated in l igsl and 2.

Fig. 4 is a-- fragmentary vertleal'scetional view taken .-ilong the line Fig. 2.

Fig. 5 is a fragmentary veriii view taken along the line Fig. 6 is a fragmentary Tei'tit vielw taken along the line. 1 Q

lajsairaa nentary. ken-al e. f h nei 111 'isiaJQian-viemsII i a nsm iessf ;.;.I4i 12isj g 1fra filter 7, section alongj-the ine F ig. 13 is af fragmentarysi in section showing a different i the machine. "l Fig..1-1 is a. fragmentarvsifl e .5'1 ing the machinenrmnge for gifinding the peripheral faces of cutter teetl n; i

T iea rmachine is adaptedfor; tors,- -pa rt cula i'hile suitable for all this class it is especially in faces. Obviously, .these wa'fpe gl 'lt'eliooidal cutting faces cannot be groundgbv ja wheel havin 'a plane grinding facea must liave a grinding f whigl islqonieal,

. a with teeth having helicoidal rontii li ill he, wheel 7 all'ladial lines beirit mciinerlii ithigrespept I to the wheel a-itis. I the helicoidaljglitting faces of a cutter are radial. :as willibe assumed, the cutter to be ground mustbeheld in such a position that its axis willintersect the line of contact between the wheel and the face being ground. The cutters will vary considerably in diameter, and relative adjustment must accordingly be effected between the wheel and cutter holder. In nocordance with the invention, this adjustment is effected along lines which are inclined with respect to the wheel axis and which are arallel with the conical surface of the w eel at the line of enga ement with the tooth faces. On account 0 this adjustment along inclined lines it is possible to change the position of the cutter holder without interering with the proper relationship be tween the grinding wheel and the cutter axis.

The grinding wheel is preferably adjustable longitudinally of its axis, so as to maintain the aforesaid intersection notwithstandin changes in the wheel surface as the resu t of dressing. Preferably there is provided in combination with the parts above referred to, a wheel dressing tool which is movable along a normally xed line, the aforesaid adjustment of the wheel servin to bring it into renewed engagement wit the dressing tool as the wheel wears. The dressing tool is so positioned as to maintain the grinding surface of the wheel in the pro 1' relation to the cutter axis.

or grinding cutters with inclined or helicoidal cutting faces the cutter axes must be arranged at an angle to the wheel axis and this angle must var with the degree of inclination of the cutting faces. I therefore provide means whereby the cutter holder can be angplarly ad'usted about a ivotal axis whic prefera ly is per en icular to the cutter axis and to the w eel axis intersecting both'of them. It is therefore possible to adjust the cutter holder angularly without disturbing the before mentioned relation of the cutter axis and the line of engagement of the wheel with the cutter faces.

The grinding wheel is indicated at 1, this wheel being mounted on a rotatable spindle 2 driven by a belt pulley 3. The spindle 2 is carried by

suitable bearings

4 and 5 mounted on the main frame 6 of the machine. The rinding wheel 1 has a grindin face 1 whic is slightly convex an conica in form, all axial lines of the face being inclined with respect to the wheel axis. conical grinding face such as the face 1" is necessary in order to enable the wheel to have line contact with the warped helicoidal front faces of the teeth. If the grinding face were lane instead of conical it obviously woul not have line contact with the warped front faces but would tend to intersect them and thus mutilate and destroy them. The exact angle of the cutting face 1 will do 'nd to some extent on the pitch of the helicoidal cutting faces to be round, but for ordinary practice'an angle 0 about 12, as shown, is satisfactory. Preferably the wheel has a second face 1" which is also convex and conical in form. The two faces meet at the periphery of the wheel, thus providin a narrow periphery which enables the whee to enter the narrow grooves between the teeth of cutters.

There is provided a cutter holder 7 which is adapted to hold a cutter A in the position indicated in Fig. 5 and to present the faces of the teeth successivel to the wheel for grinding. The cutter holder 7 holds the cutter in a position such that the axis of the cutter intersect the line of contact between the face 1 and the tooth face being ground. In this way the faces of the teeth are ground radial throu bout. Relative adjustment can be eifecte between the cutter holder and the wheel in order to accommodate cutters of different diameters. This relative adjustment is effected in the direction indicated in Fig. 5; that is, along lines parallel with the grinding face 1 of the wheel. As before stated, the face 1" is conical, the line of grinding contact being inclined with respect to the wheel axis. The relative adjustment therefore takes place along lines inclined with respect to the wheel axis and the result is that the line of grinding always intersects the axis of the cutter irrespective of the cutter diameter.

As illustrated, the axis of the wheel 1 and of the spindle 2 is horizontal and the line of movement of the cutter' holder is inclined; and the wheel and its spindle are normally fixed against bodily movement and relative adjustment is effected by bodily movin the cutter holder. This construction is pre erable for various reasons, but it may be modified without departin from the spirit of the invention in its roader phases.

In the preferred embodiment of the invention there is provided a knee 8 which is movable along an inclined slide 9 on the main frame 6. The angle of inclination of the slide 9 is the same as that of the grinding face 1 of the grinding wheel. Rotatably mounted in a bearing in the knee is a horizontal shaft having a hand wheel 10 at its outer end and a bevel gear 11 at its inner end. The. bevel gear 11 meshes with a bevel gear 12 at the upper end of an adjusting screw 13. The end of the screw fits a hearing in the knee and the lower threaded end of the screw enga es a nut or threaded boss 14 on the main rame. By means of the hand wheel the screw 13 can be turned, thus raisi' or lowerin the knee, the knee moving a ong incline lines as before stated. After ad ustment, the knee can be locked by means 0 a gib controlled by a handle 15.

In Fi 6 the cutter A is shown as being a thread cutting hob, but it will be understood that a cutter of this ty has been selected merely by way of i ustration and that any form of cutter may be round. The cutter is mounted on an arbor which is mounted between live and dead centers 16 and 17 forming parts of the cutter holder. The live center 16 is carried by a controlling and indexing head 18 mounted on a table 19. The dead center 17 is carried by a tailstock which is also mounted on the table 19 and which is adjustable longitudinally thereof along a suitable guideway 2.0.

the table 19 is not directly pivoted to the knee 8 but is connected to certain intermediate parts now to be described. The table 19 is longitudinally slidably mounted on a saddle 21 which in turn is adjustably secured to a carriage 22. The carria e 22 has a T-slot 23 into which extend T-

bo ts

24, 24 engaging the saddle 21. By means of these bolts the saddle can be connected to the carriage at any desired position. The carriage 22 is longitudinally slidably mounted on a turntable 25 which is pivotally mounted on the knee 8, being connected therewith by means of a pivot bolt 26. The turntable 25 can be secured in angularly adjusted position by means of

bolts

27, 2

For moving the carriage 22 longitudinally along the turntable 25, there is provided a lon itudinal rack 28 secured to the carriage, anf a spur gem-'29 meshing with the rack and, mounted on a horizontal shaft 30. The shaft 30 is carried by suitable bearings on the turntable and it may be turned by a suitable crank which is not shown. By turning the shaft .30 together with the gear 29, the carriage 22 may be moved as required. The carriage 22 can be held in its adjusted position with respect to the turntable by means of a ib 31 controlled by a screw 32 and a hand e 33. The screw 32 extends through a slot 34 in the knee, thus permitting the turntable to be adjusted angularly.

In order that the table 19 may be easily moved forward and backward longitudinally to carry the cutter ast the grinding wheel and thus effect grin ing of the successhe teeth, the following mechanism is rojvided. The table 19 carries a rack 35 w ich is engaged by a 5 ur gear 36. This gear is mounted on a s ort transverse shaft 37 which is rotatably mounted on the saddle 21 and which carries a crank 38. It will be seen that by turning this crank the operator can move the table 19 forward and backward as desired. The saddle 21 is provided at its rear side with a T- slot 39 by means of which two stops 40 are adjustably secured in' place, only one such stop being shown in the drawing. These stops are thereby must be turned rate of longitudinal a clamp 59 which is ada iated adapted to be engaged by a lug 41 on the table thus limiting the extent of table movement.

lVhen the cutter to be helicoidal cutting faces, table 25 together with ground has inclined as shown, the turnthe parts carried to an angle correangle of inclination of the cutting faces. These parts are shown so turned in ig. 3. It will be noted that, inasmuch as the vertical pivotal axis of the turntable intersects the axis of the cutter, the'turning movement does not disturb the relationship between the cutter axis and the line of grinding contact on the wheel. This line continues to intersect the cutter axis, thus remaining in position to grind the cutting faces radially.

As the cutter is moved longitudinally to effect grinding, it must obviously be simultaneously turned in order to maintain contact with the grinding wheel. The rate of turning must be exactly proportional to the movement and must furthermore be in exact accord with the angle of inclination of the cutting faces. For effecting this turning movement the following mechanism is provided. A. longitudinal rack 42 is carried by the saddle 21 and this rack is engaged by a spur gear 43. The gear 43 is secured to a transverse horizontal shaft 44 rotatably mounted in the head 18. At the outer. rear end of the shaft 44 is a gear 45 which meshes with a gear 46 on a second transverse horizontal shaft 47. The shaft 47 carries at its front end a gear 48. A third transverse horizontal shaft 49 is mounted in the head 18. This shaft carries at its inner end a bevel gear 50 and at its outer end a spur gear 51. The bevel gear 50 meshes with a bevel gear 52 on a longitudinal spindle the spindle 53 carrying the aforesaid center 16. Interposed between the gears 43 and 51 are two, meshing idler gears 54 and These gears are carried by a plate 56 which is adjustable, being held by a bolt 57 which enters a slot 58 in the side of the head. It will be seen that when the table 19 is moved the gear 43 will roll along the rack 42 and thus be given a rotative movement. This rotative movement will be transmitted through the

gears

45 and 46, through the shaft 47, through the

gears

48, 54. and 51 and through the shaft 49 to the bevel gear 50. From the bevel gear 50 the motion is transmitted to the bevel gear 52 and thence to the spindle 53. The spindle 53 is provided with to engage a dog C secured to the arbor In this way the rotative movement of the spindle is transmitted to the arbor and to the cutter. The amount of rotative movement of the spindle and of the cutter must be changed for different angles of inclination of the .cutting faces. Such changes can be effected by responding to the .spindle 53, is indirectl movin one or the other or both of the ears 48 an 51 and'substituting others of differ- 54 and 55 being out diameters the gears i1 differently diammoved to mes with such etered gears.

I have shown a cutter having grooves. If a cutter with right-hand grooves is to be ground, it will be understood that the turntable and all of the associated parts must be adjusted to the angle opposite to that shown. In addition, the direction of rotative motion of the cutter must be changed. This change is effected by so positioning the plate 56 that motion 18 transmitted from the gear 48 to the gear 51 through only one of the gears 54 and 55.

The gears are ordinarily inclosed b covers 59 and 59" which are shown in ig. 1 but which are omitted in the other fi res.

It will be clear that after the face 0 each tooth of the cutter has been ground, the cutter-must be indexed to prepare for the grinding of the next face. In order that indexing may be effected, the bevel gear 52, instead of being directly connected with the connected through an indexing head 60. his head is mounted to move angularly with the spindle during the grinding of a tooth, but it will be understood that the head moves through onl a small angle and never through a comp ete revolution.

The bevel gear 52 is secured to a sleeve 61 which is rotatably mounted on the spindie 53. Connected with the sleeve 61 and normally movable therewith is a housing 62 which incloses an index plate 63 secured to the spindle 53. This index plate is provided with a series of notches, the plate having the same number of notches as the cutter to be ground has cutting faces. Slidably mounted in the housing 62 is a detent 64 which is adapted to enter one ,or another of the notches in the index plate and thus rigidly connect the gear 52 with the spindle 53. The detent 64 is normally pressed into engagement with-the plate 63 [by means of a spring 65. The d of a manually operable lever 66.

indexing, the detent is withdrawn from ongagement with the plate and the spindle 53 is then turned by means of a knurled handie 67. The detent is allowed to enter the next notch of the plate and the machine is then ready for the grinding of the next tooth of the cutter.

In order for grinding to be properly effected, it is necessary to provide means whereby the cutter may be turned about its axis independently of the longitudinal movement. In this way the cutting faces will be brought into' proper relation to the grinding wheel so that grindin may be effected to the re uired extent. this angular a justment may be brought left-hand is etent can be withdrawn lay means 1' 0 effect tioned for movement along 11 order that about, the housin 62 is ad'ustablyconnected with the sfeeve 61 The sleeve 61 carries a worm wheel 68 which meshes with a worm 69 rotatably mounted in the housing 62. For turning the worm there is provided a knurled knob 70. It will be seen that by turning the worm 69 the, housing 62 together with the index spindle and the cutter may be turned with respect to the sleeve 61, thus varying the relation between the cutter faces and the grinding wheel. After adjustment, the housing can be locked against relative movement by means of a bolt entering a T-slot 71 in the worm wheel 68. This bolt can be tightened by means of a handle 72. referably in order to take tion in the gearing and in the i xin and adjusting mechanism there is provi ed a counterweight 7 2 secured to the housing 62. The grinding wheel 1 must be dressed from time to time, but its grinding surface 1 must be maintained in the same position after dressing. The wheel is therefore bod- .1ly adjustable longitudinally of its axis.

plate and the a u lost mond e Preferabl there is provided a stop which is so locate that the wheel, when engagin the stop, is so positioned that an element 0 its surface perpendicularly intersects the cutte'r axis. By preference the stop is in the form of a dressing tool which is mounted as a permanent part of the machine. This tool is so mounted that its operative movement is always alon a fixed line, advantage beingtaken of the efore' described adjustability of the wheel to move the wheel into engagement with the dressing tool. In this way the grinding surface of the wheel maintained always in the same position, notwithstanding the dressing action. As illustrated, there is a bracket 79 carried by the main frame and serving to hold a dressing tool 80. The tool is preferably posia line intersectin the wheel axis the line being preferabTy horizontal. This line is at the proper angle to the wheel axis to enable the tool to dress the surface 1 of the wheel at the correct predetermined angle. The dressing tool 80 is carried by a slide 81 which is movable along a ldeway on the bracket 79. For moving t e slide there is provided a screw 82 operable by a handle 83.

As a matter of convenience, it is some .Fig. 1. In T tion there is provided a order that this may be done, the bracket 79 is mounted on a pivot bolt 84 so that the bracket with the slide 81 and the tool 80 may be swung backward and upward. For holding the bracket in the operative posiscrew having a knurled head 85. When the screw has been withdrawn the bracket can be swung upward, the movement being limited by means,

of a stop 86.

- It has already been stated that the dressing tool is normally movable along a fixed line. In order that the tool may be preliminarily adjusted to this fixed line and in order that it may be further adjusted to compensate for wear, it ismounted on a slide 87 this slide carrying the pivot bolt 84 and the stop 86. The slide 87 is horizontally adjustable with respect to the main frame 6, being movable under the control of a screw 88.

Bolts

89, 89 extending through slots in the slide serve to lock it in adjusted positlon.

For the assistance of the operator in adjusting the dressing tool to the aforesaid fixed line, I preferably provide gaging devices such as are shown in Figs. 11 and 12. There is furnished a gage 89 made of metal and having the same shape as the rinding wheel, at least as concerns the conlcal surface 89 thereof. This gage is put inplace on the spindle approximately in position normally occupied by the wheel, as illustrated in Fig. 11. As a matter of convenience the dressing mechanism may be swung up to the position indicated in Fig. 12. The turntable 25 is adjusted to bring'the axis of the two centers 16 and 17 at ri ht angles to the spindle axis, as illustrate There is provided a ga e element 89 which is in the form of a she. t 01 pin ada ted to be mounted on the centers 16 and l This shaft or pin 89 is provided with a notch near its center which has a. plane bottom surface passing through the axis. a A bar 89 is provided which has a straight edge which contacts with the plane bottom surface of the notch. It will be seen that the shaft or in 89,- together with the bar 89, can be reely swung about the axis of the centers. B means of the screw 74 and the hand w eel 75 the gage 89". can be moved axially, and this movement is effected in one way or the other as required to enable the straight edge of the bar 89 to lieiiat a ainst the conical surface of the gage 89"". when this adjustment has been made, the surface 89 of the ga e occupies exactly the osition which is to afterward occupie by the surface 1 of the wheel, the surface of the gage at the bottom, if extended, intersecting the axis of the centers.

The gage 89 having been thus positioned,

the dressing mechanism is moved to its lower position and is adjusted by means of the detends downward from the vices described so that the tool contacts with the surface 89*, as shown in Fig. 11. In the original construction of the machine the dressing tool has been mounted to move at an angle to the wheel axis, which angle is the same as that of the gage surface 89". Therefore, when the dressing tool is adjusted to engage the said surface, it is in position to properly dress the wheel. After the dressing tool has been thus adjusted the gage 89 is removed and the wheel 1 put in place. No further adjustment of the dressing tool takes place and the wheel is moved up to the tool in order to effect whatever dressing is necessary.

The dressing tool will wear slightl as the result of its engagement with the w eel, and it will be understood that after wear has taken place the tool can be readjusted in the way already described, making use of the gage 89.

Under some circumstances it may be desirable to remove one cutter holder and substitute another. -These cutter holders may vary somewhat in construction with the result that the distance between the cutter axis and the top of the carriage 22 may vary. Inasmuch asthe axis of the cutter must intersect the line of engagement between the wheel face and the cutter faces, it will be seen that the position of the wheel and also of the dressing tool must be changed for a cutter holder of different height. These changes in adjustment may be effected by adjusting the gage 89 in the way already described.

The machine preferably includes means whereby water may be delivered to the grinding wheel. For this pur ose I provide a pump 90 adapted to be driven by a belt wheel 91. A discharge pipe 92 leads from the pump and from the pipe water can be led to the wheel by any usual or preferred means, such means not being shown in the drawings. The carriage 22 is provided with a peripheral flange 93 which serves to collect the water discharged from the wheel. The flange 93 is interrupted at 94 to permit the water to flow downward onto the turntable 25, which is provided with a peripheral flange 95. A drain pipe 96 exturntable 25, thus conducting water to a trough 97 which is mounted on the main frame. The knee 8 is also provided with a peripheral flange, thus serving to collect water which may fall on the knee. From the knee the water is dischar ed through a spout 97 into the trough 97. This trough serves to conduct the water to a reservoir in the interior of the main frame, which is ,not shown. From this reservoir the water'is withdrawn by the pump 90 and returned to the wheel.

In operation, the cutter to be ground is mounted in the usual way, as shown in Fig.

6. If necessary the carriage 22 is moved to bring the cutter into the proper general relationship to the wheel. The turntable 25 is turned to an angle corresponding to the inclination of the cutting faces and the proper gears l8 and 51 are selected to effect turning at the required rate. The two stops 40 are properly set in accordance with the position and length of the cutter. By means of the worm wheel 69 and the worm 68, the cutter is turned angular-1y, if necessary, to bring the faces into proper relation with the wheel.

Then by means of the crank 38 the table 19 and the cutter are moved back and forth to effect grinding of one tooth. tooth has been ground, the cutter is indexed and another tooth ground, this being repeated until all the teeth have been ground.

Cutters of various diameters must be ground and the machine can be readily adjusted to accommodate such cutters by raising or lowering the knee 8 and the cutter holder carried thereby. As before explained, this adjustment does not interfere with the intersection of the cutter axis with the line of contact between the conical grinding face and the cutter faces.

Fig. 6 shows the effect of the adjustment of the cutter holder for cutters of different diameters. The cutter A is shown in full lines in operative relation with the grinding wheel. A larger cutter is indicated by the dot-and-dash circle A, it being observed that the centers of both of the cutters are in line with the surface of the wheel. If cutters with different degrees of inclination are met with, the machine can be adjusted accordingly by turning the turntable 2c and the attached parts about the vertical pivotal axis. This adjustment does not in any way interfere with the intersection last above referred to.

The wheel can be dressed from time to time by means of the dressing tool 80. This tool has a normally fixed operative position and no adjustment of the tool is required.

The wheel itself is bodily moved up to the tool so as to maintain the grinding surface always in the same position.

In preliminarily adjusting the machine, the dressing tool can be moved to bring it into the correct position to bring about the before mentioned intersection of the line of grinding with the cutter axis. If it should be necessary at any time to remove the cutter holder and substitute another one. with a different elevation, the dressin tool could be adjusted to adapt the conical grinding surface of the wheel to the new position of the cutter axis.

When the machine is to be used for grinding cutters with straight lane faces, the turntable 25 is adjusted to ring the cutter axis perpendicular to the wheel axis and the After one longitudinal movement of the cutter can be effected by moving the carriage 22 with the attached parts, the table 19 remaining fixed with respect to the saddle 21 and to the table. Thus the cutter can be moved without causing any angular movement thereof such as would occur if the table 19 were to be moved on the saddle.

I have described the construction and operation of the machine in connection with cutters having the front faces of their teeth exactly radial. Frequently, however, cut ters are made with the front faces of the teeth undercut, that is, arranged so that instead of being radial they are spaced away from radial lines, as shown for instance at ill in ljig. 13. The machine embodying m nvention is equally well adapted for grind 1ng cutters of this type. The dressing tool is set in the way already described and the grinding wheel is dressed in the usual manner. Then, after swingin the dressing tool out of operative position, t e wheel is moved axially outward to the position shown in Fig. 13, being then ready to engage the nu dercut faces of the cutter teeth and grind them in the way already described in connection with the cutters with radial faces.

It is usually desirable to undercut the teeth by a definite amount which is predetermined when the cutter is originally made. It is therefore necessary to move the wheel outward'beyond its normal position by a definite predetermined amount corresponding to the desired amount of undercut. In order that the amount of wheel movement may be accurately determined, I preferably provide a graduated disk 98 which is mounted on the outer part of the screw 74. Mounted on the slide 73 is an indicator 99 adapted to coiifierate with the graduations on the disk. T e graduations are such that the operator, after dressing the wheel in its nor'mal position, can move it outward to an predetermined distance, which distance is measured b the disk graduations in connection with tile pointer. Preferably, in order that the readings may start from zero, the disk is capable of turnin on the screw. A nut 100 is provided for ockin the disk to the screw after adjustment. n operation, the operator first dresses the wheel, moving it as required for this purpose. Then the disk 98 18 adjusted to bring the zero mark thereon opposite the pointer 99. The disk is locked 1n place by means of the nut 100 and after that the wheel is moved outward, the amount of movement being indicated directly by the graduations on thedisk.

For some classes of work, cutters are made to be ground on their external or peripheral faces instead of on their radial faces. Such a cutter is shown at C in Fig. 14. The machine embodying the invention can be used for grinding such cutters by substituting a difi'erent. preferably cylindrical, wheel. such as indicated at 101 in Fig. H. The cutter is mounted on the centers in the usual wa v and is brought into .engagement with the wheel by raising the knee and all of the parts carried thereby. 1f the cutter has straight teeth parallel with the axis. it can be moved back and forth underneath the wheel by moving the carriage 22. If the teeth are helical, the cutter can he turned during grinding by means of the turning devices already described. It will be understood that the proper gears 48 and 51 are selected to effect turning at the rate corresponding to the inclination of the teeth.

If preferred, instead of using the gearing for turning the cutter, use can be made of a stop 102 which is adapted to engage the front faces of the teeth. As the cutter is moved longitudinally it can be manually turned to hold the front face of the tooth being ground in engagement with the stop.

What I claim is:

1. The combination in a cutter grinding machine, of a rotatable grinding wheel having a conical convex grinding face. a cutter holder serving to present the front faces of the cutter teeth to the said grinding face. and means for effecting relative adjustment between the wheel and the cutter support along lines parallel to the line of engagement of the grinding face with the tooth faces.

2. The combination in a cutter grinding machine. of a rotatable grinding wheel ha ving a convex conical grinding face. means for holding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face. the said holder serving to present the front faces of the cutter teeth to the said grinding face. and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

3. The combination in a cutter grinding machine. of a grinding wheel rotatable about a horizontal axis and having a convex conical grinding face, means for bolding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face. the said holder serving to present the front faces of the cutter teeth to the said grinding face, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

4. The combination in a cutter grinding machine. of a rotatable grinding wheel having a convex conical grinding face. means for holding a cutter with its axis intersectmg and perpendiculr to an element of the conical surface of the said grinding face. the said holder being movable longitudinally of the cutter axis and serving to present the front faces of the cutter teeth to the said grinding face, means for turning the cutter about its axis in proportion to the said longitudinal movement to effect the grinding of helicoidal cutting faces, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

5. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face. a cutter holder serving to present the front faces of the cutter teeth to the said grinding face, the holder being adj ustahle about a pivotal axis perpendicular to the wheel axis, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the line of engagement of the grinding face with the tooth faces.

6. The combination in a cutter grinding machine, of a rotatable grindim wheel having a convex conical grinding fiice, a cutter holder serving to present the front faces of the cutter teeth to the said grinding face, means upon which the holder is mounted for adjustment about a pivotal axis perpendicular to the wheel axis, and means for bodily adjusting the cutter holder and the pivotal mounting means therefor toward or from the wheel along lines parallel to the line of engagement of the grinding face with the tooth faces.

7. The combination in a cutter grinding machine. of a rotatable grinding wheel hav-- ing a convex conical grinding face, means for holding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face, the said holder serving to present the front faces of the cutter teeth to the said grinding face and being adjustable about a pivotal axis perpendicular to and intersecting the cutter axis, and means for effecting relative adjustment between the wheel and the cutter holder alon lines parallel to the aforesa d element '0 the said conical surface.

8. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holdinga cutter with itsaxis intersect ing and perpendicular to an element of the conical surface of the said grinding face, the

said holder serving to present the front faces of the cutter teeth to the said grinding face and being adjustable about a pivotal axis perpendicular to and intersectin the wheel axis and also intersecting the a oresaid element of the said conical surface, and means for efl'ecting relative adjustment between the said conical surface,

axis perpendicular to and the cutter axis and the wheel axis and also ing a convex conical grinding face, means for holding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face, the said holder servin to present the front faces of the cutter teeth to the said grinding face and being adjustable about a pivotal axis perpendicular to and intersecting both the cutter axis and the wheel axis and also intersectin" the aforesaid element of the said coniczd surface, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the said element.

10. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical rinding face, means for holding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face, the said holder serving to present the front faces of the cutter teeth to the said grinding face and being adjustable about a pivotal axis perpendicular to and intersecting both the cutter axis and the wheel axis and also intersecting the aforesaid element of the said conical surface, and means for bodily adjusting the cutter holder toward or from the wheel along lines parallel to the said element.

11. The combination in a cutter grinding machine, of a rotatabl grinding wheel having a convex conical inding face, means for holding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face, the

said holder being movable ongitudinally of the cutter axis and serving to present the front faces of the cutter teeth to the said grinding face, means upon which the holder is mounted for adjustment about a pivotal axis perpendicular to and intersecting both the cutter axis and the wheel axis and also intersecting the aforesaid element of the means for turning the cutter about its axis in proportion to the said longitudinal movement to effect the grinding of helicoidal cuttin faces, and means for effecting relative a justment between the wheel and the cutter holder along lines parallel to the said element.

12. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis intersecting and perpendicular to an element of the conical surface of the said grinding face, the said holder being movable longitudinally of the cutter axis and serving cutter teeth to the said to present the front faces of the grinding face, means upon which the holder is mounted for adjustment about a pivotal intersecting both intersecting the aforesaid element of the ing a grinding face at an ang said conical surface, means for turning the cutter about its axis in proportion to the said longitudinal movement to effect the grinding of helicoidal cuttin faces, means for changing the rate of turning to conform to cutters with different degrees of inclination, and means for effecting relative adj ustment between the wheel and the cutter holder along lines parallel to the said element.

13. Thetcombination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face,

, means for effecting relative adjustment between the wheel and the cutter holder longitudinally of the wheel axis to cause the perpendicular intersection of an element of the conical surface of the said grinding face with the cutter-axis, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

14. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, means for bodily adjusting the wheel longitudinally of its axis to cause the perpendicular intersection of an element of the conical surface of the said grinding face with the cutter axis, and means for effecting relative adjustment between the wheel and 'the cutter holder along lines parallel to the :Eforesaid element of the said conical surace.

15. The combination in a cutter grinding machine, of a rotatable grinding wheel havle to the wheel axis, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, means for effecting relative adjustment between the said holder serving-to present the front faces of the holding a cutter with its axis at an cutter teeth to the said grinding face, means for effecting relative adjustment between the wheel and the cutter holder lon itudinally of the wheel axis to cause an e ement of the conical surface of the said grinding face to perpendicularly intersect the cutter axis or to he at a distance therefrom, means for determining the relation between the said element and the said axis, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

17. The combination in a cutter grinding machine, of a rotatable grinding wheel having a grlndin face at an angle to the wheel axis, means or holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter. teeth to the said grinding face, means for effecting relative adjustment between the wheel and the cutter holder longi tudinall of the wheel axis to cause an element 0 the surface of the said grinding face to lie at a distance from the cutter axis, and means for measuring the said distance.

18. The combination in a cutter grinding machine, of a rotatable grinding wheel hav ing a grindin face at an angle to the wheel axis, means or holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, means including a screw for effecting relative ad'ustment between the wheel and the cutter older lon itudinall of the wheel axis to cause an e ement o the surface of the said grinding face to lie at a distance from the cutter axis, and means for measuring the said distance, the said means including a graduated disk carried by the screw.

19. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said rindin face, and a stop adapted to engage t e whee at a point so positioned that an element of the conical surface of the said grinding face will perpendicularly intersect the cutter axis.

20. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said indin face, a stop adapted to engage t e whee at a point so positioned that an element of the conical surface of the said grinding face will perpendicularly intersect the cutter axis, and means for effecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

21. The combination in a cutter grinding machine, of a rotatable grinding wheel having a grinding face at an angle to the wheel axis, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, means for effecting relative adjustment between the wheel and the cutter holder lon itudinally of the wheel axis, a stop adapte to engage the wheel at a point so positioned that an element of the surface of the said grinding face will perpendicularly intersect the cutter axis, and means for measuring any relative longitudinal adjustment beyond the position determined by the said stop.

22. The combination in a cutter grinding machine, of a rotatable grinding wheel having a grindin" face at an angle to the wheel axis, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, and a dressing tool adapted to en age the wheel and movable along a normally fixed line so positioned that an element of the surface of the said grinding face after dressing will perpendicularly intersect the cutter axis.

23. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face at an angle to the wheel axis, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face and being adjustable about a pivotal axis perpendicular to and inter secting the cutter axis, and a dressing tool adapted to engage the wheel along a normally fixed line so ositioned that an element of the surface 0 the said rinding face after dressing will perpendicu arly intersect the cutter axis and also intersect the pivotal axis.

24. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holdin a cutter with its axis at an angle to t e wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, and a dressing tool adapted to engage the wheel along a normally fixed line so positioned that an element of the conical surface of the said grinding face after dressing will for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face and being adjustable about a pivotal axis perpendicular to and intersecting the cutter axis, and a dressing tool adapted to engage the wheel along a normally fixed line so positioned that an element of the conical surface of the said rinding face after dressing. will perpen- 'cularly intersect the cutter axis and also intersect the pivotal axis.

26. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle 7 to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, a dressing tool adapted to engage the wheel along a normal y fixed line so positioned that an element of the conical surface of the said grinding face after dressing will perpendicular] intersect the cutter axis, an means for e fecting relative adjustment between the wheel and the cutter holder along lines parallel to the aforesaid element of the said conical surface.

27. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding acutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face and bein adjustable about a pivotal axis perpendie at to and intersecting the cutter axis, a dressing tool adapted to engage the wheel along a normally fixed line so positioned that an element of the conical surface of the said grinding face after dressing will perpendicularly intersect the cutter axis and also intersect the pivotal axis, and means for effecting relative ad'ustment between the wheel and the cutter older along lines parallel to the aforesaid element of the said conical surface.

28. The combination in a cutter grinding machine, of a rotatable grinding wheel having a grinding face at an angle to the wheel axis, means or holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, a dressing tool adapted to engage the wheel along a normally fixed line so ositioned that an element of the surface 0 the said grinding face after dressing will perpenicularly intersect the cutter axis, means for adjusting the wheel longitudinally of its axis to brin it into engagement with the dressing too and means for measuri' any lon itudinal adjustment of the wh efi be ond t e position of dressing.

The co bination in a cutter finding machine, of a rotatable grinding w eel havtool ada ted ing a convex conical rinding face, means for holding a cutter with its axis below and at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, and a dressing tool adapted to engage the wheel along a normally fixed horizontal line so positioned that an element of the conical surface of the said grinding face after dressing will perpendicularly intersect the cutter axis.

30. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face, and a dressing tool adapted to engage the wheel along a normally fixed line so positioned that an element of the conical surface of the said grinding face after dressing will per endicularl intersect the cutter axis, the fiessing ing movably mounted so that it may be move out of operative position when not in use.

31. The combination in a cutter grinding machine, of a rotatable grinding wheel having a convex conical grinding face, means for holding a cutter with its axis at an angle to the wheel axis, the said holder servin to present the front faces of the cutter teet to the said, grinding1 face, a dressing tool to engage t e wheel along a normsl y fixed line, and means for adjusting both the wheel and the dressing tool bodily along lines parallel with the wheel axis to bring about the perpendicular intersection of an element of the conical surface of the said grinding face with the cutter axis.

32. The combination in a cutter grinding machine of a rotatable grinding wheel having a grmdin face at an angle to the wheel axis, means or holding a cutter with its axis at anangle to the wheel axis, the said holder serving to present the front faces of the cutter teeth to the said grinding face a dressingtool adapted to engage the whee alo a straight line means for adjustin the ressing tool bodi y along lines paralle with the wheel axis, and a ge adapted. to be so located that the dress tool when brought into contact with it wil be in ositool adapted to engage the wheel alonga straight line, means for adjusting the dressing tool bodily along lines parallel with the wheel axis, and a gage ada ted to be so located that the dressin too when brought into contact with it wi 1 be in position to dress the wheel so as to bring about the perpendicular intersection of an element of the conical surface of the said grinding face with the cutter axis.

34. The combination in a cutter grinding machine, of a rotatable spindle, a rinding wheel on the spindle having a grin ing face at an angle to the wheel axis, means for holding a cutter with its axis at an angle to the wheel axis, the said holder servin to present the front faces of the cutter teeth to the said grinding face, a dressing tool adapted to engage the wheel along a normall fixed line, means for adjusting the ressing tool bodily along lines parallel with the w eel axis, and a gage adapted to be placed on the wheel spindle approximately in the position normallfieoccu led by the wheel, the said ga to so iocated and shaped that the essin tool when brought into contact with it will be in osition to dress the wheel so as to bring a out the perpendicular intersection of an element of the surface of the said grinding face with the cutter axis.

35. The combination in a'cutter grinding machine, of a rotatable spindle, a grindin wheel on the spindle having a convex conica grinding face, means for holding a cutter with its axis at an angle to t e wheel axis, the said holder servin to present the front faces of the cutter test to the said rinding face, a gage adapted to be placer? on the spindle approximately in the osition normally occupied by the wheel, t e gage having a convex conical surface similar to that of the wheel, a gage element including a bar adapted to be positioned with a straight edge surface thereof passing through the normal line of the cutter axis, means for moving the spindle lon 'tudinally to adjust the conical surface 0 the gage into line contact with the straight edge surface of the bar, a wheel dressing tool adapted to contact with the ga and means for bodily adjusting the too to, bring it into position frf r lllnovementfalon the collilical surfage o tegageatertegage asbeenajusted as before stated.

In testimony whereof, I hereto afiix my si nature.

g FRIEDERICH MULLER.