US1617167A

US1617167A - Grinding machine

Info

Publication number: US1617167A
Application number: US563591A
Authority: US
Inventors: Schramm Carl
Original assignee: Pratt and Whitney Co Inc
Current assignee: Pratt and Whitney Co Inc
Priority date: 1922-05-25
Filing date: 1922-05-25
Publication date: 1927-02-08
Anticipated expiration: 1944-02-08

Description

. mime? F 3, 1927' c. SCHRAMM GRINDING MACHINE Filed May 25, 1922 3 Sheets-Sheet 1 INVENTOR ATTORNEY 1 1617167 E'eb. 8, SCHRAMM a GRINDING MACHINE 'Filed may 25, 1922 :5 Sheets-sheaf. 2

' INVENTOR ATTORNEY I 1,617,167 Feb. 8,1927. Q SCHRAMM GRINDING MACHINE Filed May 25, 1922 SSheets-She'et 3 I I g I I I:

INVENTOR V cm! 5W F w w/wma ATTORNEY Patented Feb. 8, 1927.

UNITED STATES PATENT OFFICE.

CARL SCHRAMM, OF WEST HARTFORD, CONNECTICUT, ASSIGNOR TO PRATT & WHIT- NEY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

GRINDING MACHINE.

Application filed May 25,

and particularly to machines for grinding,

the teeth of center reamers.

One object of my invention is to provide a grinding machine that shall relieve and grind the teeth of center reamers in an efficient manner by the radial face of a grinding wheel.

Another object of my invention is to provide a. grinding machine having a radial face grinding wheel en a ing the teeth of a.center reamer that sha e provided with means for effecting feeding movements of the grinding Wheel and relieving movements by the reamer.

Another object of my invention is to provide a grinding machine of the above indicated character that shall have the teeth of the reamer engage the radial face of the grinding wheel near the peripheral face with the point of the reamer on the peripheral face of the grinding surface, and that shall relievethe reamer teeth in timed relation to the rotation thereof while effecting feeding movements by the grinding wheel. I

Another object of my invention is to provide a grinding machine of the above indicated character that shall oscillate the reamer about a center beyond the end thereof while effecting feeding movements of the grindin wheel andthat shall not only be provided with means for stopping the reamer in a predetermined rotative position but also shall insure the insertion ofa new reamer in a predetermined rotative position.

A further object of my invention is 'to provide a center-reamer grinding machine that shall have the grinding Wheel so mounted on slides as to effect feeding movements perpendicularly to the axis of the reamer,.to effect adjustment parallelly of the reamer axis and also to effect a rotary adjustment. Moreover, the niachine'shall be provided with means for adjusting the roamer towards the grinding wheel, auxiliary means for vertically and horizontally adjusting the grinding wheel, means for oscillating the reamer to effect relieving movements while effecting feeding movements by the grinding wheel, and means for insuring the stopping of the reamer in a predetermined rotative position.

At the present time, it is customary to grind the teeth of center reamers by means 1922. Serial No. 563,591.

of the so-called pencil grinding wheels. Such pencil grinding wheels, as is well known, are diflicult to maintain in good condition and wear out very rapidly. Heretofore, it has been deemed impracticable to grind center-reamer teeth by either the radial or the peripheral grinding face of a grinding wheel by reason not only-of the number of teeth on the reamer but also by reason of the long extended point on such a tool.

It is possible to I grind the ends of twist drills on the radial face of a grinding wheel inasmuch as such tools have only two flutes and the ends of the tool are not, sharp pointed and extended as in the case of center reamers. In grinding twist drills on the radial face of a grinding wheel, the axis of the tool makes a relatively large angle with the radial face of the grinding wheel and no trouble is experienced in relieving the teeth formed by the two flutes on the drill. However, in the case of center reamers, the point of the tool is somewhat extended and by reason of such shape and the large number of teeth, it is impracticable to grind and relieve the teeth in the manner now employed in grinding and relieving the ends of twist drills. The teeth of a center reamer are so close together as to prevent the relieving of one tooth without interfering with the next succeeding tooth.

In a machine constructed in accordance with my invention, a reamer is mounted on a slide with one end thereof in engagement with the radial face of a grinding wheel. The reamer engages the grinding face near the peripheraledge thereof and the e eme point of the reamer is located on the peripheral edge of the radial grinding face. By so positioning the reamer with respect to the grinding ace, it is possible to relieve the teeth without any interference. The grinding wheel is provided with vertical and horizontal adjusting slides which also carry means for dressing the radial and, peripheral face of the wheel. The vertical and horizontal adjusting slides are mounted on a feeding slide which is movable in a direction er ,endicular to thejaxis' of the tool. The ee ing slide is mounted with a slide for adjiisting the wheel parallelly to the axis of the reamer. Means is also provided for effecting a rotary djustment of the grinding wheel,

A clutch is provided forconnecting the reamer to a sourbe of power. Such source of power also serves to oscillate the reamer for effecting relieving movements and to effect feeding movements by the grinding wheel. The reamer is oscillated about a center just beyond the end thereof in order to relieve the teeth of the reamer to the point thereof. A cam wheel, which is controlled by the clutch, carries a cam member which serves to effect feeding movements Fig. 2 is a front elevational view of the machine shown in Fig. 1.

Fig. 3 is a side elevational view of the machine shown in Fig. 1.

Fig. 4 is a rear elevational View machine.

Fig. 5 is a detail of the reamer setting mechanism.

Fig. 6 is a section taken along the line 66 of Fig. 1.

Fig. .7 is a section taken along the line 77 of Fig. 2.

Fig. 8 is a section taken on the line 8--8 of Fig. 7.

Fig. 9 is an end view of the grinding wheel and dressing attachments.

Referring to the drawings, a grinding ma chine is shown having a main frame 1 for supporting a main driving head 2, a spindle head 3. and a grinding wheel head 4. The main driving head 2 comprises a bracket 5, which is secured to the main frame 1 in any suitable manner, and a pulley bracket 6 which is fastened to the main bracket 5. A

of the shaft 7. which is carried by the

brackets

5 and 6, has a pulley 8 nniunted thereon. Une end of the shaft 7 abuts a short shaft 9 which is mounted on an arm 10 of the member 15, which is.pivotally mounted on a plate 16, is provided with a bifurcated end portion which is fitted to a groove 17 formed on the clutch member 12. The plate 16 is secured to the two

arms

10 and 18 of the bracket 5 in any suitable manner. A spring member 19 is provided for exerting a force on the yoke member normally tending to engage the. teeth on the two clutch members. One end' of such spring member abuts one end of the yoke member 15 and the other end thereof engages an adjustable bolt 20, which is secured to the arm 10 of the bracket 5, as shown in Fig. 3 of the drawings. The yoke member 15 carries a rod 21 near the end thereof for a purpose to be hereinafter set forth. One end 22 of .Theworm member 28 is mounted on the shaft between the armslO and 18 of the bracket 5 and meshes with a worm wheel 30. The worm wheel 30 is mounted on a bolt 31. The bolt 31 is secured to the bracket 5, as shown in Fig. 6 of the drawings.

A cam member 32, which is secured to one side of theworm wheel 30, serves to control the feeding movements of the machine. The cam member 32 engages a roller 33 which is mounted on a lever 34. The lever 34 is connected to a shaft35 and controls the feeding movements of the machine in a manner to be hereinafter set forth.

A pin 36, which projects from the side of the worm wheel 30 opposite to the cam member 32, serves to operate the clutch 11 to disconnect the shaft 9 from the shaft '2' under certain conditions. iVhen the lever 23 is moved towards the right, as shown in Fig. 6 of the drawings, the rod21 is moved to a position in the path of movement of the pin 36. Consequently, when the pin 36 engages the rod 21, the yoke member 15 is moved against the action of the spring 19 to open the clutch ll. The purpose and operation of such means for opening the clutch will be described more fully hereinafter.

A gear wheel 37 is mounted on the shaft 27 between the arm 18 of the bracket 5 and the bracket 6. The gear wheel 37 meshes with a gear wheel 33,1vhich is mounted on a. shaft 39, and with a gear wheel 40 which is mounted on a short shaft 41. The shaft 41 is provided with hearings on the arm 18 of the bracket 5 and the bracket 6 and carries an adjustable change-gear lever 42. The lever 42 carries a gear wheel 43. The lever 42 is provided with a slot 44 within which is slidably mounted a bolt for supporting a gear wheel 45. The gear wheel 45 not only meshes with the gear wheel. 43

but also with a gear wheel 46 which is fixedly mounted on a shaft 47. The shaft 47 extends through the main frame 1 of the machine and controls the relieving movements of the tool, ma manner to be here1n-' after set forth. 1 I The shaft 39; which carries the gear wheel 38, is provided with bearings in the

brackets

5 and 6. The shaft 39 is connected to a shaft 50 in the spindle head 3 bymeans'of The main spindle head 3 carries a tool which is to be ground upon its cutting surfaces, this being usually a center reamer. The reamer 55 engages the radial face 56 of a grinding wheel 57. The spindle head comprises a bracket 58 having

arms

59 and 60. The base of the bracket 58 is fitted to a guideway 61 that is Secured in any suitable manner to the main frame 1. A screw 62 is provided for effecting adjustment of the spindle bracket 58 along the guideway 61.- A screw 63 is provided for locking the spindle bracket in anyset position.

A main spindle 64, which carries the tool 55 to be ground, is provided with hearings on the arms 59 and of the spindle bracket 58. A worm wheel 65, which is mounted.

on the spindle 64, meshes with a worm member 66. The worm member 66 is mounted on the shaft 50. The shaft 50 is provided with hearings in a-worm wheel housing 67 and supplies power for rotating the'spindle The tool 55is engaged by a collet chuck .238 which is controlled by a lever 69. The

collet chuck is operated by a sleeve 70 which extends into the spindle 64.v Two levers 71. which are pivotally mounted on the spindle '64, are provided with extended end portions which are operated to effect axial movement of the sleeve 70 to open and close the collct chuck. The opposite ends of the levers 71 are operated by cam surfaces 73 which are formed on a sleeve member 74. The axial movement of the sleeve member 74 serves to operate the levers 71 to open and close the collet chuck.

A-bolt 75. which projects from one side of the .arm 59 of the spindle bracket. carries a. shifter bracket 76. The shifter bracket 76 is provided with a bifurcated end portion 77 which is fitted to a groove 78 on the sleeve 74. The bracket 76 is shiftablv mounted on the bolt and is provided with :ack teeth 79 which mesh with gear teeth 50. The gear teeth 80 are formed on the and of the lever 69. The lever 69 is p1votally supported on a bolt 81, which in turn is supported on an'arm 82. The arm 82 projects. from the bracket "58. From the above descriptionit is apparent the operation of the lever 69 serves to open and close the collet' chuck 68'for permittingthe removing and the replacing of center reamers therein. v

The support for the spindle bracket 58 is pivoted on a bolt 83 which is secured to the mainframe 1 of the machine. The spindle head is oscillated about the bolt 83 as a center in order torelieve the teethon the center reamers. The oscillation of the spindle head is effected byv means of a cam mem-' ber 84 which is mounted on the shaft 47. as shown in Fig. 3 of the drawings. The cam member 84 engages a roller 85 on a bolt '86. The bolt 86 is connected to the support for the bracket 58. A spring member 87 is provided for normally forcing the spindle bracket 58 towards the right, as shown in Fig. 3 of the drawings. One end of the spring 87 abuts the support for the spindle" bracket and the other end of the spring abuts a lug 88 which projects from the main frame 1 of the machine. A set screw 89. which is adapted to engage the lug 88. serves to limit the movement of the spindle bracket towards the right, as shown in Fig. 3 of the drawings.

It is desirable not only to stop the movement of the main spindle with the reamer in a. predetermined rotative position, but

also to insert a new reamer in position with the teeth thereof in a predetermined rotative position. A bracket 90 having a rod 91 rotatably mounted in the end thereof is secured to the arm 60 of the, main spindle bracket in any suitable manner. The rod 91. which is rotatably mounted in the bracket 90, carries an adjustable clamp 92. The

clamp 92 in turn carries a second rod 93..

An arm 94 is rotatably mounted on the rod 93 between a collar 95 and a stop member 96. The arm 94 is adapted to rest on a lug 97-projecting from the stop member 96, as shown in Fig. 5 of the drawings. The arm 94 is provided with an end portion 98 which is adapted to be engaged by the end of the reamer being inserted in the collet chuck. A screw 99 projects through the arm 94 for engaging one of the reamer teeth to limit the rotative position of the reamer. It is apparent that by means of the arm 94, reamers are inserted in the chuck in a predetermined rotative position.

The grinding wheel 57 is supported on a spindle 100which is provided with hearingspn the

arms

101 and 102. The

arms

101 and 102 project from a horizontal slide 103. The horizontal slide 103 is controlled by a screw 104 in a well known manner and is mounted on a vertical slide 105. The vertical slide 105 is controlled by a screw 106.: The vertical slide is locked in any set position by a screw 107=and the horizontal slide is locked in any set position bv a screw 108'. The vertical slide 105 is mbunted on a bracket 109.

The bracket 109 is mounted on a slide 110 which serves to effect movement of the grinding wheel 57 parallel to the axis of the main spindle. The bracket 109 is secured to the slide 110 by means of T-headed bolts 111 wh ch engage T-slots in the slide. By means of such bolt and slot connections a rotative or angular adjustment of the grinding wheel relative to the tool being ground may be easily effected. A screw 112 is provided for effecting movement of the slide 110.

The slide ,110 is mounted on a feeding slide 113 The feeding slide 113 is directly mounted on the ma n frame 1 of the machine and is automatically operated in timed relation to the operation of the main spindle. A screw 114, which effects movement of the feedslide, carries a gear wheel 115 which meshes with a gear wheel 116 on a shaft 117. The shaft 117 projects through the main frame 1 of the machine and may be operated manually by a hand wheel 118, as shown in Fig. 7 oil-the drawings, or may be operated automat cally in timed relation to the rotation of the main spindle.

A collar member 119 is fixedly mounted on a sleeve member 120. The sleeve memher is fixedly mounted on the shaft 117." A.

' ratchet wheel 121, which is rotatably mounted on the sleeve 120, is connected to the collar member 119 by means of a suitable friction clutch 122. in plate 123, which carries a pawl 12%, is rotatably mounted on the sleeve 120. The plate 123 is operated by a rod 125 for effecting movement of the ratchet wheel 121. and accordingly for efiecting movement of the. shaft 1'17 to feed the grind'ng wheel towards the reamer. An adjustable member 126, which is mounted on the collar member 119, is adapted to engage a stop member 127 to limit the feeding movement. The rod 125, which operates the plate 123, is connected to a lever 128. Thelever 128 is mounted on the shaft which is operated by the lever 34. The rod 125 is connected to the lever 128 by a bolt and slot connection in order to adjust the feed ing movement of the grinding wheel which is etlectml in accordance with the rotation of the main spindle Referring to Fig. 9 of the drawings, it will be noted the vertical slide 105 carries a guard 129. Such guard 129 also serves to carry means for dressing the peripheral and the radial face 0. the grinding wheel. As shown in the drawings, the dressing attachment for the peripheral face of the grfnding wheel comprises a diamond which is mounted on a screw 130. The dressing attachment 131 for dressing the radial lace of'the grinding wheel is controlled by a lever 132. A detailed description of such dressing attach ment is deemed unnecessary inasmuch as the rotation in any set position, projects throughv Such rod 2% to the front of the machine. is operated by means of a hand lever 13 1. In grinding a center reamer by the machine, a reamer is first inserted in the collet chuck by operating the lever 69 and then the rotative'position of the center reamer is adjusted in accordance with the position of .the arm 94. The reamer is set near the peripheral edge of the radial grinding face of the wheel with the point thereof upon such peripheral edge. Care should be taken to insure that the point of the center reamer is behind the center of the bolt-83 about which the main spindle head is adapted to oscillate. By so positioning the center reamer, it is pos sible to relieve'the teeth to the point therof. The relative position of the reamer and'the slide may be adjusted by means of the grinding wheel slides and also by means of the slide which snpportsthe center reamer. A feeding movement of the grinding wheel may be efiected for each revolution of the center reamer or for any set number of revolutions. Inasmuch as the feeding move-- ments are efiected by the same source of power asefiects rotation of the center reamer, it is apparent the feeding movements are efiectedin timed relation to the ated as to move the rod 21 into the path of movement of the pin 36 on the worm wheel 30. Upon engagement between the pin 36 and the rod 3.1, the yoke member 15 is operated to open the clutch 11- and separate the shafts 7, and 9. Accordingly, the rotation of the center reamer is stopped with the reamer in a predeterm ned rotative position. It will be noted that the clutch 11 not only controls the rotation of the center reamer but also the relieving movements and the feeding movements.

Modifications in the machine and in the arrangement and location of parts may be made within thespirit and scope of my invention and such modificat'onsare intended to be covered by the appended claims.

5 at I claim is:

1. In a grinding machine, the combination with a rotating. ll wheel, and

lit

face and extending tangentially thereof; of;

means for-oscillating said toolabout a point beyond theend thereof to effect relieving movements.

3.' In a grinding machine, the combination with a grinding wheel having a radial grinding face, and means for positioning a center reamer in engagement with the grinding face of said wheel, said 'reamer' being positioned near the periphery of the grind-- mg surface and extending tangentially thereof the point of the'reamer bein at the peripheral edge of the grinding sur ace, of means for rotating the reamer and said wheel, means for oscillating the reamer to relieve the teeth thereon, and means for,

feeding the grinding wheel in timed relation to thereamer rotation.

4. In, a grinding machine, the combination with a rotating grinding wheel, means for mounting a pointed tool, having a pinrality of teeth, in en agement with, a radial face ofsaid. Wheel, the pointed end of said tool beinglocated on the peripheral edge of the grinding surface, said tool extending tangentially 0 said wheel, and means for rotating the tool, of means for oscillating the tool about a point beyond the end 'thereof to relieve the teeth, and means for feeding the grinding wheel in timed relation to the rotation of the tool.

5. In a grinding machine, the combination with a grinding wheelhaving a radial grinding face, means for positioning a center reamer in' engagement-With the grinding face of said wheel, said reamer being positioned near the periphery of the grinding surface with the oint ofthe reamer at the peripheral edge 0 the grinding surface and extending tangentially of the wheel, and means for rotating the reamer and said wheel, of means for oscillating the reamer in timed relation to the rotation thereof and about a center beyond the end thereof to relieve the teeth, and means for effecting feeding, movements between the grinding 1 wheel and the reamer in timed relation to the reamer rotation.

6. In a grinding machine, the combination with a rotating grinding wheel, aslide for supporting a tool in engagement with a radial face of the grinding wheel, the end of said tool being located a proximately on the peripheral edge of sai grinding face, means for rotating the tool in engagement with. the grinding wheel, and means comprising. a cam member operated-by the tool rotating means for oscillating said slide to relieve the teeth of the tool, of means operated by the tool rotating means for feeding the grinding wheel towards the tool in timed relation to the blank rotation.

7. In a grinding-machine, the combination with a rotating grinding wheel, a slide] forsupporting a pointed tool in engagement with av radial face of the grinding wheel, two slides for supporting the grinding wheel and adapted to adjust the grinding wheelperpendicularly and parallelly to the axis of the tool, means for effecting rotary adjustment of the wheel with respect to the tool, means for rotating the tool in engagement with the grinding wheel, and means comprising a cam member for oscillating the tool slide in timed relation/to the rotation of said tool, of means for efiecting feeding movements of the grinding wheel in a direction perpendicular to the tool axis and in timed rotation.

8. In a grinding machine, the combination with a rotatin grinding wheel,means relation to the blank comprising a slide or supporting a ointed tool in engagement with. a radial ace of said grinding wheel, said slide serving'to adjust the --tool with respect to thewheel, and means for rotating the tool, of" a cam member operated by said tool rotating means and serving to oscillate the tool in timed relation to the tool rotation, means for insuring the stopping'of the tool rotation with the tool. in a predetermined rotawheel in timed relation to the tool rotation.

9. In a grinding machine, the combination with .a rotating grinding wheel, a slide for supporting a pointed tool in engagement with a radial face of the grinding wheel, the pointed end of said tool being located on the peripheral ed e of said grinding face, means for rotating t e tool in engagement with the grinding wheel, and means comprising a cam-member for oscillatin said tool slide in timed relation to the rotation of said tool, of means for feeding the grinding wheel in a direction perpendicular to the tool axis and in timed relation to thetool rotation,-.a-nd

automatic means for stoppi-ng'the rotation of the tool in a .tive position, and means for feeding the wheel operated by said tool rotating means,

til?

means comprising a cam member on said gear wheel for efl'ecting feeding movements of aid grinding wheel in timed relation to the tool rotation, and apin mounted on said gear wheel for insuring the stopping of the tool rotation with the tool in a predetermined. rotative position.

12. In a grinding machine, the combination with a rotating grinding wheel, means for supporting apointed tool in engagement with a radial face of the grinding wheel, means comprising a clutch forconnecting a source of power to the tool to efiect rotation thereof, and a gear wheel operated by said tool rotating means, of means comprising a cam member carried by said gear wheel for efiecting feeding movements between the tool andthe grinding wheel in timed relation to the tool rotation and means comprising a pin projectin from said gear 7 wheel for opening said c utch under certain conditions to insure the stopping ofthe tool rotation with the tool in a predetermined rotative position.

13. in a grinding machine, the combination with a rotating grindin wheel, means for mounting a pointedtoo to engage a radial face of thegrinding wheel near the peripheral edge thereof, means comprising a clutch and a gear wheel for connecting a source of power to efiect rotation of the tool, and means operated by the source of power for oscillating the tool to relieve the teeth thereon, of -means comprising a pin projecting from said'gear wheel for opening I said clutch under certain conditions to insure the stopping of the tool rotation with the tool in a predetermined rotative position.

it. in a grinding machine, the comhinw tion with a rotating grind 1;- wheel, means for mounting a pointed too to engage-a radial face of the grinding wheel near the peripheral edge thereof, means comprising a clutch for connecting a source of power to the tool to efi'ect rotation thereof, and means operated by said source or power for oscillating the tool to relieve the-teeth thereon, of a gear wheel connected to said clutch, means comprising a cam member mounted on said gear wheel for efiecting feeding movement's hy the grinding wheel, and means comprising a projecting said gear wheel for opening said clutch under certain conditions to insure the stopping of the tool rotation with the tool in a predetermined rotative position. v

15. In a grinding machine, the combination comprising a rotating grinding wheel, means for mounting a pointed tool in engagement with a radial face of the grinding wheel, said tool being located with the pointed end'thereof on the peripheral edge of the grinding face, and means for insuring the mounting of the tool in the'machine in a predetermined rotative position.

16. In a grinding machine, the combination with a rotating grinding wheel, and means for mounting a pointed tool in engagement with a' radial face of the grinding wheel, said tool being located near the peripheral edge of the grinding surface, of means for rotating the tool, means for insuring the stopping of the tool rotation with the tool in a predetermined rotative position, and means for insuring the insertion of a new tool in the machine in ap-redetermined rotative position.

1?. in a grinding machine, the combination witha rotating grinding wheel, means comprising a slide for mounting a pointed tool having a plurality of teeth, in engagement with a radial face of thegrinding wheel, said tool being lobated near the peripheral edge of the grinding surface, of means for rotating the tool, means for insuring the stopping of the tool rotation with the tool in a predetermined rotative position, and means mounted on the tool slide for insnring the insertion of a new tool in the machine in a'predetermined rotative position,

18. lna grinding machine, the combination with a rotating grinding wheel, means for mounting a pointed tool in engagement with a radial face of the grinding wheel, a slide movable perpendicularly of the axis of the tool for supporting the grinding wheel, a slide movable parallelly to the axis of the tool for supporting the first grinding wheel slide, and means for rotating the tool, of means for effecting relieving movements of the tool and feeding movements of the grinding wheel in timed relation to the ro F tative movement of the tool.

19. In a grinding machine, the'combination with a rotating grinding wheel, means comprising a slide for mounting a pointed tool in engagement with a radial face of the grinding wheel, a slide for so supporting-the grinding wheel as to effect adjustments of the grinding wheel perpendicularly of the axis of the tool, a second slide for supporting the first grinding wheel slide and adapted to eii'ect adjustments of the grindin wheel parallelly to the axis of the-tool, an means on the first grinding wheel slide for edecting rotary adjns .ent of. the grinding wheel, of means r re dine the tool, means for oscilill) lating the tool in timed. relation to the rotation thereof, and means for efl'ecting feeding movements on the second grinding wheel comprising a slide for mounting a pointed.

tool in engagement with a-radial face of the grinding wheel, said tool bein located with the pointed end thereof on t e peripheral edgeof said grinding face, means comprising a clutch member for connecting the. tool to a source of power, and a gear wheel operated from said source of power through the clutch, of means comprising a cam mounted on said gear wheel for effecting feeding movements of the grinding wheel, means comprising a cam member operated from said source of power for effecting 0s illatory. movements of the tool to relieve the teeth thereon, and means comprising a pin projecting from said gear wheel to stop a rotative movement of the tool in a presignature.

determined rotative position under certain conditions.

21. In a grinding machine, the combination with a rotating grinding wheel, means for mounting a pointed tool in engagement with a radial face ofthe grinding wheel, a feeding slide for supporting the grinding wheel and movable perpendicularly to the tool axis,a slide for supporting the feeding slide and movable parallelly to the tool axis,

a Vertical and a horizontal movable slide mounted on -the feeding slide for directly supporting the grinding wheel, andineans mounted on the feeding slide for dressing the radial and peripheral faces of the grinding wheel, of means for rotating the tool, and means for effecting relieving movements of the tool and feeding movements of the grinding wheel in timed relation to the tool rotation.

In testimony whereof, I hereto a-ffix my CAR-L SCHRAMM.