US2561981A

US2561981A - Cam grinding apparatus

Info

Publication number: US2561981A
Application number: US65921A
Authority: US
Inventors: Clarence J Green
Original assignee: Norton Co
Current assignee: Saint Gobain Abrasives Inc
Priority date: 1948-12-17
Filing date: 1948-12-17
Publication date: 1951-07-24
Anticipated expiration: 1968-07-24

Description

July 24, 1951 c. J. GREEN cAM @BINDING APPARATUS 4 Sheets-Sheet 1 Filed Dec. 17, 1948 July 24,1951 c. J. GREEN 2,561,981

CAM GRINDING APPARATUS Filed Dec. 17, 1948 4 Sheets-$11661. 2

a' Y Fig.6

. I nuevztor CLA/ENCE IG/eem gm w. ttorney July 24, 1951 c. J. GREEN 2,561,981

CAM GRINDING APPARATUS Filed Dec. 17, 1948 l 4 'sheets-sheet s u I nuentor' F g 10 CLARENCE LIS/25m .Bgm b5. edd".

Httorneg C. J. GREEN A GRINDING APPARATUS July 24, 1951 4 Sheets-Sheet 4 Filed Dec. 17, 1948 Patented July 24, 1951 CAM GRINDING APPARATUS Clarence J. Green, Worcester, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application December 17, 1948, Serial No. 65,921

8 Claims. (Cl. 51-101) The invention relates to grinding machines and more particularly to a cam grinding machine.

One object of the invention is to provide a simple and thoroughly practical cam grinding machine for grinding predetermined contours on a. work piece. Another object is to provide a cam grinding apparatus for grinding a contour of a predetermined length on the periphery of a work piece. Another object is to provide a. cam grinding apparatus for grinding a contour of a prel determined length around the periphery of a roll, regardless of the diameter of the roll, from the same master cam. Another object is to provide a cam grinding apparatus with an adjustable speed-up device for speeding up rotation of the work piece being ground relative to rotation of the master cam. Another object is to provide a cam grinding apparatus having a single master cam with a direct proportional device to speed up the rotation of the roll being ground` relative to the rotation of the master cam so that the original shape can be extended around the periphery of the roll as it is reduced in size by regrinding operations so as to produce the same shape in blanks being rolled.

Another object of the invention is to provide a cam grinding apparatus for grinding a predetermined shape in the periphery of a roll used in a rolling operation. Another object is to provide an apparatus for grinding the periphery of rolls with an adjustable work rotation speed-up mechanism for` speeding up rotation of the roll being gyiund relative to the master cam whereby `a single naster cam serves to grind a form of the same peripheral length regardless of the diameter of the roll being ground. A further object is to provide a cam grinding apparatus for grinding a form of a predetermined length on the periphery of a roll being ground by means of a single master cam as the roll is reduced in diameter due to successive regrinding operations so that l uniformly shaped blanks may be rolled there- In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a fragmentary plan view of the improved cam grinding apparatus having parts broken away and shown in section to show part of the work driving mechanism;

Fig. 2 is a fragmentary front elevation of the work driving mechanism showing the two-speed clutch, taken approximately on the line 2-2 of Fig. 1;

Fig. 3 is a right hand end elevation, taken ap- 2 proximately on the line 3-3 of Fig. 1, showing a portion of the work driving mechanism;

Fig. 4 is a fragmentary cross section, on an enlarged scaleI taken approximately on the line 4 4 oi Fig. 1, through the rock bar showing a right hand elevation of the work speed-up and slow-down mechanism;

Fig. 5 is a fragmentary vertical sectional view, taken approximately on the line 5-5 of Fig. 4;

Fig. 6 is a fragmentary vertical sectional view, taken aproximately on the line 5-5 of Fig. 4, showing the work speed-up mechanism in elevation;

Fig. 7 is a fragmentary cross sectional view, on an enlarged scale, taken approximately on the line 4-4 of Fig. 1, similar to Fig. 4 but showing the parts in another position;

Fig. 8 is a diagrammatic view of a metal rolling apparatus in which the lower roll is ground on the improved cam grinding machine;

Fig. 9 is a view of the lower roll showing the extended formed surface on the roll when the roll has been reground to a smaller diameter;

Fig. 10 is a side elevation of an article rolled 5 by the apparatus shown in Fig. 8; and

Fig. 11 is a front elevation of the grinding machine. Y

A cam grinding apparatus has been illustrated in the drawings comprising a base 9 which supports a longitudinally movable table ||l on the usual V and flat way (not shown) on the base of the machine. A transversely movable rotatable grinding wheel is provided which is mounted in a conventional manner on a transversely movable wheel slide 30 so that the wheel may be moved toward and from the work table I0 to ygrind a work piece to the required and predetermined sizeA A manually operable feed wheel 3| is mounted on the front of the machine base and is operatively connected to rotate a feed screw (not shown) to cause the grinding wheel and the wheel slide 30 to move transversely toward and from the work table I0, depending upon the direction of rotation of the feed wheel 3|. This mechanism is substantially identical with that disclosed in the prior U. S. patent to C. H. Norton No. 762,838 dated June 14, 1904, to which reference may be had for details of disclosure not contained herein. The feed wheel 3| may be actuated either manually or automatically as desired. A mechanically actuated feed pawl 32, such as shown in the prior patent above referred to, is reciprocated automatically to advance the grinding wheel at the ends of the reciprocatory stroke of the work table i0.

The work table I may be reciprocated longitudinally relative to the base 9 by means of a manually operable traverse mechanism comprising a traverse wheel 200 rotatably mounted on the front of the machine base. The traverse wheel 200 is connected to rotate a gear 20I which meshes with a gear 202 mounted on a rotatable shaft 203. The shaft 203 also supports a gear 204 which meshes with a rack bar 205 depending from the underside of the work table 0. It will be readily apparent from the foregoing disclosure that a manual rotation of the traverse wheel 200 will be imparted through the rack and gear mechanism above described to produce a longitudinal traversing movement of the table I0. The direction of rotation of the traverse wheel 200 serves to determine the direction of Ymovement of the table I0.

The table I0, if desired, may be reciprocated longitudinally by a power operated mechanism such as shown in the prior patent above referred to. This mechanism may comprise a rotatable power driven shaft 206 which is driven by means of a multiple speed drive contained with a casing 201. The rotatable shaft 206 is connected through a reversing clutch (not shown) which is actuated by means of a reversing lever 208. The reversing lever 208 is actuated by adjustable table dogs 209 and 2I0 which are adjustably mounted in a T-slot 2II formed in the front edge of the table III. This table traverse mechanism above described is substantially identical to that shown in the above mentioned prior patent, to which reference may be had for details of disclosure not contained herein. The table I0 serves as a support for a rock bar I2. The rock bar I2 is provided with trunnions I3 and I4 at its opposite ends (Fig. 1) which are rotatably journalled in brackets I5 and I6. The brackets I5 and I6 are flxedly mounted on the upper surface of the table I0.

The rock bar I2 serves as a support for a headstock I1 and a footstock I8 which are provided with work supporting centers I9 and 20 respectively. The headstock I1 is provided with a rotatably mounted master cam spindle 2I which is supported in bearings 22 and 23. A master cam 24 is mounted on the master cam spindle 2|. A frame 25 is xedly mounted on the table I0 and serves as a support for a rotatably mounted master cam roller 26. The master cam roller 26 is keyed on a rotatable shaft 21 which is journalled in brackets 28 and 29 which are formed integral with the frame 25.

A casing 35 is xedly mounted on the table I0 and serves as a support for a work driving motor 36. The work driving motor 36 is provided with a motor shaft 31 which is connected to rotate a worm 38. The worm 38 meshes with a worm gear 39 which is keyed on a rotatable shaft 40. The shaft 40 is journalled in antifriction bearings 4I and 42 which are supported within the casing 35.

A two-speed drive is provided between the shaft 40 and the master cam spindle 2I to facilitate changing the speed of rotation of the master cam spindle 2I and the work piece being ground. This mechanism may comprise a pair of gears 45 and 46 which are keyed on opposite ends of the shaft 4l. The gears 45 and 46 mesh with gears 41 and 48 respectively which are keyed on rotatable

clutch members

49 and 50 respectively. The

clutch members

49 and 50 are rotatably supported on a shaft 5I which is journalled for rotation within bearing surfaces formed within the 4

clutch members

49 and 50. A slidably mounted clutch member 52 (Fig. 2) is slidably keyed on the shaft 5I. A manually operable clutch shifting lever 53 is fixedly supported on a rock shaft 54. The rock shaft 54 also supports a yoked member (not shown) which engages a groove (not shown) on the clutch member 52. It will be readily apparent from the foregoing disclosure that by manual shifting of the lever 53, the

clutch member 52 may be engaged either with the clutch member 49 or the clutch member 50 to impart a rotary motion to the shaft 5I.

`A multiple V-groove pulley 55 is keyed on the left hand end of the shaft 5I. The pulley 55 is connected by multiple V-belts (not shown) with a multiple V-groove pulley 56 which is supported by an anti-friction bearing 51. A universal joint 58 is drivingly connected with the pulley 56. The universal joint 58 Ls lixedly connected to one end of a shaft 59. A universal joint 60 connects the right hand end of the shaft 59 with the master cam spindle 2|. It will be readily apparent from the foregoing disclosure that by providing the

universal joints

58 and 60, a substantially uniform rotation may be imparted to the master cam spindle 2l and the work piece being ground during oscillating movement of the rock bar I2.

In the rolling of shaped metallic blanks such as is used in the silver-ware and cutlery trade, it is desirable to provide a roll for the rolling operation having a predetermined form on its periphery so that a work blank being rolled will be produced having the desired longitudinal shape. In order to produce a predetermined shape in the periphery of the roll used in the rolling operation from a single master cam, it is desirable to provide a suitable speed-up mechanism between the master cam spindle and the work piece being driven thereby to facilitate an acceleration of the work speed relative to the speed of rotation of the master cam 24 so that as the roll being ground is reduced in diameter by successive regrinding operations, a form of a predetermined length may be produced on the peripheral surface of the roll. This mechanism enables rolling work pieces to the same longitudinal shape regardless of the diameter of the roll being ground without the necessity of providing a plurality of master cams. The speed-up mechanism as illustrated in the drawings is mounted on the right hand end of the master cam spindle 2I.

The master cam spindle 2I is provided with an integral flange 65 (Figs'. 5 and 6) and a cylindrical portion 66. The cylindrical portion 66 of the master cam spindle 2I serves as a support for an annular member 61. A spacing collar 68 is interposed between the annular member 61 and the flange 65. A plurality of clamping screws 69 (only one of which is shown in Fig. 5) are provided for locking the annular member 61 and the spacing collar 68 to the flange 65 so that the annular member 61 is rotated with the master cam spindle 2|. A bracket 10 is mounted on the periphery of the annular member 61. A pair of clamping screws 1I and 12 pass through the bracket 10 and have their heads engaging an arcuate T-slot 13 formed in the periphery of the annular member 61. It will be readily apparent from the foregoing disclosure that by loosening the screws 1I and 12, the bracket 10 may be adjusted about the periphery of the member 61 as desired. The bracket 10 serves as a support for an arcuate member 14 which is pivotally connected by means of a stud 15 with the bracket 18. The right hand end of the arcuate member (Fig.

. 5' 4) is provided with a roller 16 which is supported by a stud 11 carried by the arcuate member 14. The roller 16 is arranged to engage the internal cam 1-8 formed on the inner periphery of an annular ring 19. The ring 19 is provided with a pair of downwardly extending lugs 80 and 8| which are fastened to the rock bar I2 by means of

cap screws

82 and 83 so that the annular ring 19 is rigidly positioned on the rock bar I2.

A slide 85 is supported by a radially extending slot 86 formed in the annular member 61.- The slide 85 carries a stud 81 which rides in an elongated arcuate slot 88 formed in the arcuate member 14. A pair of

plates

89 and 90 are flxedly mounted on the peripheral surface of the annular member 61 to prevent the slide 85 from moving outwardly beyond the maximum position as illustrated in Fig. 4.

A driving head 94 is rotatably mounted on the cylindrical portion 66 of the master cam spindle 2| and is held in position thereon by means of a collar 95. The driving head 94 is provided with an angularly positioned slotl 96 which is preferably arranged at approximately 45 relative to a radial -plane passing through the axis of the master cam spindle. The slide 85 is provided with a stud 98 which supports a roller 91. The roller 91 rides in the slot 96. It will be readily apparent from the foregoing disclosure that when the slide 85 is moved downwardly (Fig. 4) in a radial direction relative to the annular member 61, the roller 91 carried thereby riding in the angular slot 96 will impart an accelerating motion to the driving head 94 so that the head 94 moves at a faster rate than the rotation of the annular member 61.

A tension spring 99 is provided for exerting a pull on the driving head 94 in a clockwise direction relative to the annular member 61. The left hand end of the spring is fastened to a stud carried by the annular member 61. The right hand end of the spring is fastened to a stud |0| carried by the driving head 94. An adjustably mounted stop screw |85 is supported by a lug |06 on the annular member 61. A lock nut |01 serves to lock the screw |05 in adjusted position. It will be readily apparent from the foregoing disclosure that the tension of the spring 99 will serve normally to maintain a stop surface |08 on the driving head 94 in engagement with the stop screw |05.

A driving block ||0 is adjustably supported by means of a clamping bolt I I on the driving head 94. The head of the clamping bolt III rides in an arcuate T-slot formed in the front face of the driving head 94.

A driving dog (not shown) is mounted on the neck I|3 of the roll ||4 to be ground. The driving dog is arranged to engage an aperture ||6 in the face of the driving block I0.

The cam grinding apparatus disclosed is particularly intended for grinding a peripherally extending form on a roll utilized for a rolling operation for rolling metallic blanks -such as spoon blanks for manufacturing silver spoons and the like in which a blank must be formed of varying thickness and shape from length to length. To illustrate, a rolling apparatus has been illustrated in Fig. 8 comprising the shape droll I I4 which is located in a vertical plane with a cylindrical roll II5. A metal blank I|6 to be rolled is provided at its right hand end with an enlarged end portion ||8v which is arranged to be engaged by a longitudinally extending `groove I I1 formed in the periphery of the roll I4. The roll I I4 is provided with a predetermined shaped portion represented by the arc A-B-C which when rotated in a clockwise direction will roll the blank I I6 to produce a shaped blank |20 (Fig. 10).

As one example, the roll |I4 is preferably 51/2" in diameter and the finished blank to be rolled is approximately 9". in length which means that the form produced on the roll ||4 `represented by the arc A-B-C equals approximately 187.5". The master cam 24 is preferably designed so that it will generate the predetermined shape on a 51/2" diameter roll. When the roll I|4 becomes worn during usage itis necessary to regrind the periphery thereof to provide the desired shape.

and finish for the rolling operation. As the roll ||4 is reduced in diameter dueto successive regrinding operations, it is necessary to extend the formed surface represented by the arc A-B-C so that a 9" blank may be rolled thereby. For example when the roll ||4 becomes worn due to usage and successive regrinding operations from 51/2" in diameter to 5" in diameter, it will be necessary to increase the formed surface thereon as represented byl the arc A-B---C to approximately 206.3 in order to produce a formed blank 9" in length (Fig. 9).

After the groove ||1 becomes ground away, it may be necessary in a separate grinding operation to regrind the longitudinal groove ||1 so that it will grip 4the end ||8 of the blank II6 to be ground.

During the initial grinding operation on a 51/2" diameter roll, the stop screw |05 is adjusted to turn the driving head 94 in a counterclockwise di rection relative to the annular member 61 so that the'angular slot 96 causes a downward movement of the roller 91 (Fig. 4) to move the slide 8,5 also in a downward direction so as to rock the member 14 in a clockwise direction to position thefrollerv 16 so that it will not engage the cam face 18 during its rotary motion. The initial roll having the groove II1 previously formed therein may be ground in the usual manner by feeding the grinding wheel II transversely into the surfacebf the roll I|4 while the master cam spindle 2| rotated. The rock bar I2 is oscillated in a controlled movement by means of the master cam 24 to generate the predetermined contour on the rll II4. This operation in case of a 9 blank as illustrated will produce a form A-BC. The remaining surface of the roller as represented by the arc A-D-C being formed as a true cylindrical surface. The roll ||4 thus produced is mounted in the rolling machine and workpieces are inserted as the roll revolves so that the thickened end portion II8 is engaged by the groove |I1 which serves to pull the blank through the machine and due to the shape generated on the surface as represented by the arc A-B-C, to generate a formed blank |28 as illustrated in Fig. 10.

When the initial roll becomes worn and requires regrinding, the regrinding reduces the diameter of the roll and it is necessary to extend the formed surface A-B--C through a greater angle in order to produce a blank of the same length and shape. This is accomplished by rotating the master cam spindle 2| so that the roller 16 coincides with the 187.5 position on the graduated scale formed on the side face of the ring 19. With the roller 16 in this position, the screw |05 is adjusted so that the tension of the spring 99 will shift the driving head 94 in a clockwise direction relative to the annular member v61 so as to allow the slide 85 to move upwardly (Fig. 4) a suicient distance so that the member 14 is rocked in a counterclockwise direction until the roller 16 engages the surface of the cam 18. On the next regrinding operation it will be necessary to lengthen the arc of grinding A--B-C and to accomplish this, the bracket may be shifted around the periphery of the annular member 61 by loosening the clamping bolts 1| and 12 so that when the master cam spindle 2| is rotated, the roller 1B riding on the gradually rising surface of the cam 18 from the 187.5 position to zero will transmit an accelerated motion to the driving head 94 to gain the additional arc required so that the peripheral length of the surface represented by the arc A-B-C (Fig. 8) will remain constant. In actual practice the member 14 may be calibrated with a graduated scale so that if a two degree gain is required, the bracket 10 may be precisely positioned by consulting a calibrated table to give the desired results.

After the bracket 10 has been adjusted to its new position, the grinding operation may then be started. As the roller 16 rides around the surface of the cam 18 in a counterclockwise direction, the rise of the cam 18 acting through the roller 16 serves to rock the member 14 about its pivot stud in a clockwise direction to cause a downward movement of the slide 85. The downward movement of the slide 85 serves through the roller 91 riding in the angularly positioned slot 96 to accelerate the rotary motion transmitted to the driving head 94. It will be readily apparent from the foregoing disclosure that by adjustment of the bracket 10 relative to the annular member 61, the desired amount of gain may be had in the acceleration of the driving head 94 to produce the desired surface on the roll ||4.

This adjustment is required on successive regrinding operations so that for example when the roll has been worn by use and regrinding t0 5" in diameter, it will require approximately 206.3 of arc A-B-C (Fig. 9) to produce the desired length and contour on the finished blank |20. When the roll becomes worn to the 5" diameter the roller |16 engages the cam 18 at the l87.5 position and during its rotation from this position to zero, the roller 16 through the rocking of the member 14 causes a downward movement of the slide 85 to move the roller 91 downwardly in the angularly positioned slot 96 so that the driving head 94 is accelerated to move through 206.3 thereby producing a surface 0n the roll as represented in Fig. 9 that will produce a rolled blank |20 of the same length and contour. It will be readily apparent from the foregoing disclosure that by setting up the roller 16 for the initial angular rotation required and then by adjusting the position of the bracket 18 to vary the angular acceleration of the driving head 94 any desired movement may be obtained to equalize and offset reductions in diameter of the roll being ground.

As illustrated in the drawings, the cam face 18 has been graduated to 240 which is suflicicnt for certain classes of rolls to be ground. The remaining ungraduated portion is a substantially cylindrical clearance face joined with a blending curve which blends with the cam shape at the zero point. If desired the cam face 18 may be extended through a greater arc if the nature of the work to be ground requires.

The operation of this improved grinding apparatus will be readily apparent from the foregoing disclosure. Assuming adjustments have been previously made so that the roller 16 remains out of contact with the cam 18, the initial full diameter roller H4 may be ground by the usual cam grinding operation, that is, by rotation of the master cam spindle which transmits the motion of the master cam 24 to cause a predetermined rocking movement of the rock bar l2 to generate the predetermined shape as represented by the arc A-B-C (Fig. 8) on the roll I4. After the roll becomes worn and it becomes necessary to regrind the surface thereof the mechanism is adjusted in a manner above described that is in the present case rotating the master cam spindle 2| until the roller 16 is opposite the 187.5 position after which the stop screw |05 is adjusted into engagement with the stop surface |88. The bracket 10 is then adjusted to shift the arcuate member 14 so as to vary the lever arms between the axis of the stud 15, the axis of the stud 81 and the axis of the stud 11 so that during the rotation of the master camshaft 2| and the annular member 11 through l87.5, the driving head 94 will be accelerated the desired amount so that the form generated on the roller |I4 as represented by the arc A-BC will be equal in length to the initial arc. On each successive regrinding operation it will be necessary to make adjustment of the position of the bracket 10 to compensate for reduction in diameter of the roller being reground to insure generating a form of the predetermined peripheeral length.

As disclosed above, the mechanism has been described as set up for producing a formed blank |23 which is 9" in length. If it is desired to produce blanks of a different length, the mechanism is set up accordingly to generate the desired arc A-B-C so that when used in the rolling operation it will produce a blank of the desired length and contour.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cam grinding machine having a base, a transversely movable rotatable grinding wheel thereon, a longitudinally movable table on said base, a rock bar on said table, a rotatable master cam spindle on said rock bar, means to rotate said spindle, a work supporting center on said spindle, a footstock having a work supporting center, means including a master cam on said spindle and a follower roller on said table to rock said bar during a grinding operation to generate a predetermined peripheral contour on the work piece, a work driving head rotatably supported on said spindle, means including an adjustable cam mechanism to accelerate the rotation of said driver relative to said spindle, and means to adjust said cam mechanism so as to vary the angular acceleration of the work driver to generate a form of a predetermined peripheral length on the periphery of a work piece being ground regardless of the diameter of the work piece.

2. In a. cam grinding machine having a base,

a transversely movable rotatable grindingl wheel thereon, a longitudinallymovable table on the-A base, a rock bar on said table. a rotatable master cam spindle on said rock bar. means to rotate said spindle. a work supporting center onsaid spindle. a footstock having ay work 'supporting center, means including a mastercam on said spindle and a follower roller on said table .toV lrock said bar duringa grinding operation to generate a predetermined contour on-the work piece being'ground, a driving ange 'xedly mounted on said spindle,'a`workv driver rotatably mounted on said spindle adjacent to said flange, and ad- -d'riverxto facilitate grinding a form 6. In a cam-grinding machine'havinga base.

a transversely movable. rotatable grinding wheel thereon.` aflongitudinally -rnovablet'ablaa rock baron` said table, va rotatablefwork support on.

justable driving connections includingan adjust- 'able cam mechanism interposed between -the flange and driver to accelerate the driver relative to the Vmaster cam spindle so that-single master cam serves to generate a form of a predetermined y peripheral length regardless of the` diameter'of the work piece.

3. In a cam grinding machine having a' base.

l a transversely movable rotatable grinding lwheel thereon, a longitudinally movable table onA the I base, a roel-: bar on saidtable, a rotatable mastercam spindle on said rock bar. means vtorotate said spindle, av work supporting centeron said l spindle, a footstock having a work' supporting I center, means including a master cainfon. said spindle and a follower roller on said tableta rockl said bar during agrinding operation to generate a predetermined contour on the work piece being.` ground. a driving harige iixedlyv mounted on said said rock g bar including a 'rotatablem'aster cam 1 vspindle having a.;w'orksupportingfcenterj and va iootstock center, means to rotate said master cam spindleVmeans including a master carnon said spindle 'anda follower rolleron vsaidtable'to roel; said bar vduring-a grinding loperation -,toge 1f1erate a predetermined contour on the roll to be ground,

said Vmaster cam being shapedto generate a forml Y ofapredetermined peripheral length on al fullsizejrolltofbe ground; a work driving head rotatably supported on said' spindle, means including an'adjustable cam-,mechanism to accelerate the rotation of. the driver relative to the rotation ofthe 'spindle, and meansl to adjust said cam mechanisms() as to' vary the acceleration of the A tions.

spindlega work driver rotatably mounted on said spindle adjacent to said ilange. a radially movable slide on said flange. va non-radial groove'on said groove, and means including an adjustable cam mechanism 'to move said slide so as to accelerate the rotation of the driver relative to said ilange to facilitate grinding a Iorinof apredetermined.` peripheral length on tlieperiphery of the-work piece being ground regardless of the diameter of the work.

4.'In a camgrinding machine as claimed in claim 3, wherein the work driver further includes a cam xedly mounted on' said rock bar, an adjustable bracketmounted on the periphery of;

said ilange, an arcuate shaped 'arm havingone end `p ivotally mol'u'ited on said bracket.` a rollerl on the other end of said arm engageable vwith vsaid cam, an elongated arcuate slot in said arm, and a stud on said slide which rides in said slot.; the adjustment of said bracket serving to .vary the extent of movement of said slide and thereby vary the extent of the accelerated movement-oi the driver relative to the spindle to facilitate grinding a form of. a predetermined Aperipheral length on the periphery of the work piecebeing around. f

5. In a camgrinding machine as claimed claim 3, in combination withthe parts and feadriver. a roller on said slide which rides in said l driver'v relative to the rotation of the spindle to 1 vfacilitate grinding a form of the same peripheral length on the periphery of the roll vas itis reducedjin diameterv'by successive grinding operav -7. Ina camgrinding machine as claimed in claim r6,- in combination with the parts and fea#v tures therein s'peciiied vof-a 'work drive block adjustably mounted'on saidwork driving head, and means to adjust said block vrelative to said. head toffacilitate positioning of the roll to be ground relative tothe master cam. 1 .'8.'In al camgrinding machine as claimed inv` claim 3, wherein the work driver further includes acam xedly mounted-on vsaid rock bar. an ad- 'justab'le bracket mounted on the periphery of' .t said angeanharcuateshapedarm having one Ivend "pivtall'y mounted onsai'd bracket. aroller on the other end-ot said arm engageable with said cam, anelongatedarcuate slot in said arm. and a stud on said vslide which rides Tin said slot, the

adjustment of said bracketfserving `to vary the extent ofvmovefment 'or said slide and thereby-l vary the extent ofthe accelerated movement of the driven relative tov the A spindle to facilitate grinding aiorxn oa lpredetermined peripheral. length on the `peripherynf the workpiece being `v ground. saidxcainon .the'rock-barbeing so shaped tures therein specified of an adjustable stop screw j on said ange engageable with a stop surface on said driver. and a tensionvspring connected be'-l tween the ange and the driver normally to maintain said stop' surface in engagement-with lthe stop screw. said stop screw 'serving to limit v2.115,06:

ille of this'patent: i.'

Number Name v l Date" 1,879,506 Roberts -n." vsept.f.27; .1932 2,404,573A G laf 23;