US2646652A - Internal grinding machine - Google Patents

Description

July 28, 1953 H. L. BLOOD 2,646,652

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 9 Sheets-Sheet l July 28, 1953 H. L. BLOOD 2,646,652

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 9 Sheets-Sheet 2 lllllll- July 28, 1953 H. L. BLOOD 6,

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 9 Sheets-Sheet 5 W1 flai July 28, 1953 Filed Aug. 16, 1951 H. BLOOD 2,646,652

INTERNAL GRINDING MACHINE 9 Sheets-Sheet 4 July 28, 1953 H. BLOOD 2,646,652

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 I 9 Sheets-Sheet 5 July 23, 1953 H, L, BLOOD 2,646,652

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 9 Sheets-Sheet5 MfW July 28, 1953 H. L. BLOOD INTERNAL GRINDING MACHINE 9 Sheets-Sheet 7 Filed Aug. 16, 1951 vulva MLfiA l y 8, 1953 H. L. BLOOD 2,646,652

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 9 Sheets-Sheet 8 F9713. as; M

July 28, 1953 H. L. BLOOD 2,646,552

INTERNAL GRINDING MACHINE Filed Aug. 16, 1951 9 Sheets-Sheet 9 Patented July 28, 195 3 UNITED STATES FPA-ATENT OFFICE INTERNALfGRINDING MACHINE Harold L. Blood, Worcester, ""Mass., assignor to The Heald Machine Company, Worcester, Mass., a; corporation of Massachusetts 7 Application'August 16, 195 1,"Serial No.242',102

' 22 Claims.

This invention relates to internal grinding machines of the centerless or chuckless type, in

which workpieces are guidedbytheir preformed outer surfaces of revolution while beingrotated,

and a rotating wheel or tool-is applied to refine internal surfaces 'of'revolution in the workpieces. One difiiculty with such machines is "that in practice, some irregularities produced by previous operations are presenton the outer guide surface of a workpiece and these irregularities adversely to-the-direction ofradial-feed motion of the -wheel. The support surface extends approxi- --mately the same distance on either side of a line through the center ofthe-work normal to a" line through thecenters of the work and tool. With this-arrangement, two ormore workpieces --may be finished-simultaneously by the same tool to the-same inner diameter wlthina close toleraffect the accuracy of the inner finishedsurface being generated, and arereproduced, at least in part, in the inner surface.

Internal grinding machines have been' constructed in whichan annular'workpieceis held against an end stop by one'or more skewed-rolls applied to'a preformed outer surface of thework 'workpieces will affect the diameter of the inner surface. The Einstein et alppatent'sh'ows the work held against a-stationary -end stop-and I have found it difiicult to rotate thework smoothly when using this principle. All these difficulties are avoided in the present invention.

As a part of the present invention, the eifect'on theinner surface of irregularities in the outer surface is minimized by holding this outersurface against a stationary concave shoe or support surface which substantially conforms with the outer surface and extendscircumferentially in contact therewith sufiiciently to bridge irregularitiestherein and to fixthe center of rotation of the rotating workpiece.

It is highly'desirable to locate this 'support'surface, with respect to the line of contact between tool and work, so that variations in theouter diameters of successive workpieces will have a comparatively small effect on the diameters'of their inner surfaces. Otherwise, the manufacturing tolerance on the outer diameter would add to the variations in inner diameter which would be produced by the finishingoperation.

As another feature of the invention, the support surface is, therefore, so located 'that the centers of workpieces having-different outer dia meters-fa1l-in a line substantially at rightangles the work and support. "difiicult to rotate thework byfriction means, and excessive wear of the support :would occur. The present invention includes means for holding the 0 workagainstthe support-without excessive fricance.

if the-suportsurface is located below the work and the -tool is fed-horizontally, thewheel tends to lift the workoutof the support. *This lifting must be prevented, but-it 'is-also "desirable at the same time to prevent highfriction between It would otherwise be tion.

"It wouldbepracticable torotate the "Work in the support-bypressing a' face of the work against a backplaterotating 'onafixed axis, and it has been customary to locate such a plate eccentric with respect to the work, in a direction which insures against lifting the work away from the support. But-an eccentric driving plate has the disadvantage of increasing thefriction between work and support andincreasing the wear on both the support and'the plate. The present invention includes end stop means comprising a "back" plate -which-is-free torotate on an axis determined by the work, and which fixesthe plane of the face 'of the work-accurately. Since there is ---no* slippagebetween the plate and-the work,-the coefficient of friction between the plate and work is high,it-being-well known that the friction of rest is ordinarily higher than the fric- 'tion ofmotion.

The high coefficient of friction means that a comparatively small force is sufficient to hold the work against the rotating plate and thereby to rotate the-work.- The present invention, therefore, makes it possible, instead of-applying an axial forceagainstonefaceof theJwork, to press'a' pair of'skewed rollsagainst the periphery of the work at nearly opposite-points'andinthis way to develop sufficient axial force. Suchan arrangement permitstheiwheelhead to be brought 'closeto' th'e Work, sincethere need be no inter- --vening:'parts. Ehe length of the wheel spindle may thus be reduced to a minimum, which is often a-greatradvantage in internal grinding.

Whenrol1s-are pressed against the periphery vof-the work it'is .essentialthatthey do not disturb-thework. in the. support. Meansare, therefo'fe, provided to insure that equal force is exerted upon the work by opposite rolls.

The same pressure means may be used both to hold the work against both the work support means and the back plate or other end stop means. It is important to note, however, that such pressure means are not fixed and do not in themselves locate the work but rather serve to urge the work against the work locating means.

It is also important to note that the problems presented in internal centerless grinding with which the present invention is concerned, are quite different from those of external centerless grinding.

In external grinding problems, a very large wheel mounted on a heavy spindle may be used so that spindle deflection and wheel wear problems are not acute. The work is supported on the same surface which is being ground, or at least another external surface and the means for loeating and rotating the work can be arranged quite differently with relation to the wheel than is the case in internal grinding and such arrangements are at least unsatisfactory and usually useless in connection with internal grinding.

In internal grinding, since the grinding wheel or tool must be introduced inside of a comparatively small bore, the wheel is much smaller than an external type wheel and in order to reach into the work it must be mounted on a comparatively long and thin spindle. Therefore, spindle deflection problems arise causing inaccuracies in the work, particularly if the work locating and support means prevent reduction of spindle length to a minimum. The present invention is concerned, therefore, not only with means for locating work by its external surfaces while finishing an internal surface, but also with the means in combination therewith for rotating the work and for holding it against the locating means and at the same time allowing application of an internal finishing tool which has as short a spindle as possible.

In the drawings:

Fig. l is a partial front elevation of a machine of the invention.

Fig. 2 is a view similar to Fig. l with some of the parts broken away and others in section.

Fig. 3 is a right end elevation of the work support arrangement.

Fig. 4 is a plan view of rangement.

Fig. 5 is a section on line 5-5 of Figs. 2 and 9.

Fig. 6 is a section of a modification of the work support means taken on line 6--6 of Fig. '7.

Fig. I is a right end view of Fig. 6.

Fig. 8 is a plan view of Figs. 6 and 7.

Fig. 9 shows another modification viewed in section.

Fig. 10 is a partial right-end view of the embodiment shown in Fig. 9.

Fig. 11 is a plan view in section of a further modification.

Fig. 12 is an end view of Fig. 11.

Fig. 13 is an end view of another modification.

Fig. 14 is a side view of Fig. 13 partly broken away and in section.

Fig. 15 is an end view of a further modification.

Fig. 16 is a side view of Fig. 15 partly in section.

Fig. 17 is an end view of driving means for the modification of Fig. 16.

Referring to Figs. 1 and 2, the machine includes a table I, arranged to reciprocate on a the work support argrinding tool or wheel being used herein to cover the usual internal grinding wheel comprising bonded abrasive material or the more recent metal tools which are adapted to serve the same function of finishing an internal surface to close tolerances. The spindle I is journaled in a wheelhead 3 on the bridge. A dressing or truing tool is indicated at 188. The wheelhead 3 is mounted on a slide 2 which slides on ways on the bridge 4 to provide transverse or cross feed of the wheel 6.

Referring also to Fig. 3, an annular workpiece 8 rests on a work support 9, which is adjustably mounted on a body l0 carried by the table I. The support 9 has a concave support surface 9a, preferably faced with tungsten carbide or other wearresisting material, which substantially conforms with the preformed periphery of the work and extends circumferentially in contact with the periphery sufificiently to bridge irregularities therein and to fix the center of rotation of the work. The support 9 is shown relieved to insure contact with the work near the ends of the support. In many applications a continuous support is satisfactory particularly where uniformity of outside workpiece diameters is to be expected, but it is preferable to divide the work support 9 as shown because an undersized workpiece has a tendency to rock in a support having a continuous surface whereas a divided surface provides a saddle which serves to maintain in fixed radial position successice workpieces which vary slightly in outside diameter. This invention, however, covers the use of both continuous and divided concave workpiece support surfaces. PThe workpiece 8 is rotated in the support 9 by rolls H and 12 which engage the periphery of the work. The rolls H and 12 are journaled in arms 13 and I4 fulcrumed on studs I5 and H5 in the body I0 and are driven by sheaves I7 and I8 which are connected to the rolls by shafts, not

shown, running through the arms I3 and H. A belt I9 driven by a sheave 20 on a drive motor 2! passes over an idler 22 and around the sheaves I! and Hi to drive them. The sheaves I8 may be made slightly smaller than the sheave ll, the difference being exaggerated in the drawings, so that the surface of the roll l2 moves downward in contact with the work 8 at a higher speed than the surface of the roll I i moves upward in contact with the work, tending to hold the work down in base 5 to which is fastened a bridge 4. A grinding tool 6 is carried on a spindle I, the designation contact with the support 9. The rolls H and I2 may be journalled, as shown, slightly above the center of the work to aid in holding it down.

Tension in the belt l9 tends to swing the rolls 1 i and 12 so that they each exert a force on the work, these opposite forces being substantially equal since the difference between the diameters of the sheaves ii and i8 is slight and may be compensated for by suitable arrangement of the angles formed by the belt i9. Additional forces between the rolls H and i2 and the work 8 are provided by a spring 23 which pulls on the arms 13 and Id with equal force. This balancing of pressures is important to prevent the work from being pushed away from the position in which it is located by the support 9.

The rolls H and 12 are skewed, as best shown in Fig. 4, so that when rotated in the direction indicated by the arrows they hold the work 8 against a cup shaped back plate 2 as well as holding it down in the support 9. This is due to the fact that when the rolls are skewed and rotated as shown, they exert a component of force on the workpiece which is axial and toward the fixing of the plane :of the end :endof the cylinder 1-5.

- diameter.

.' radially, by a conventional 'fiatplatezballthrust bearing-ii in the body it. Thebackplateidis not journaledi in the? body It, =-but.".its1 weightds .t-aken by pins 55,; Fig.1 5,.-.w.hichzare urged. toward .theicenter by "light.springszfifiandengage a surface 5'! on. one i of the; races ofpthe' .bearingfifid mounted on the backplate; 2.4, tthereby; support- ..ing the backplate 24 .in a-substantially:concentric relation tothe bore ofthebodygl ;;when no work is present. When a.workpiece: 8. is pressedagainst the backplate 2'4 and rotated,.the work drives the plate, by; friction; the, plate; turning. on -an;.,axis

' determined by; the .work andqbomp-ressing l the springsr56 .as necessary.

-.'Ihe backplate 24 accuratelylfixes :the plane of the end surface 'OfjWOllLphGld againstgits- @The" support 9 is shown relatively short; in an.- a ial direction so that it will not interfere with: the surface by. the .backplate.

wheel 6; the innersurfaqe :ot a workpiece' maybe ground on anaxis precisely at right; angles ,to an end surface; and concentric.withtheperiphery inat' least one plane, and a" succession of .work-' j pieces having slightly; difierent outer diameters be ground-to substantially thesame inner diameter.

- piston rod 25 and piston. ailin acylindenfifi when a valve 66, Fig; 4,; is turned; manually, on byany desired means, to-admitfluid pressure to the left As thefrodgflfi moves; to the, right, Fig.1 2 it; carries am'e mber r29, which,

through. a. links-3t, rocksian 'escapement; lever M in a clockwise direction so that an arm-32'blocks the fall of a workpiece'tt' in magazine 34-and an arm 35v releases a. workpiece 36,'Which' drops in-tc the support 9 whenthe finishedworkpiece 8 is" ejected. T'henremberQQ-is provided wit-harms 3?: and 38, Fig. 4; which when moved. totheright, coact with inclined surfaces =39; and im-on the levers l3 :and M to :push' these levers apart, swinging therolls l ij and it away from the'workpiece .to permit:ejection thereof.

The principles of the support arrangement which has been described 1 maybe =utilized in grinding two or moreworkpieces simultaneously. -=to the same inner diameter, since .inanufacturing toierances on the :outer diameter move. the center of the work-at righhangleSjthatheJdirection of a feed and so: have' negligible effect on y-the inner y In this embodiment two workpieces u 8 .and'

are shown resting-.ina support-B.againsta;,back- I plate 24. Inthis casefthe; support 931s; axially long enough to: seat more than; one: Wolfkpiece.

gvided; in.:.e.achrw rkiil oat ns. su f it r upi prn-ajand; cqnn ctedtda. streamlines: 9

Such an arrangement 'is. .2 shown "in --Figs;'6,\7.and:8. I

poriiother'ifluidtmay beintroducedlundertpressure 'through the line 95. to. reducethexcontactpressure 5 between the. work i 81. and tit-and thersupport." 9,

.Jowering-the.friction.which.mightotherwisepre- 5 vent; the..-work fromt rotating. freely in the sup- J The :worktmayyber rotated eitherzby the rolls which .areqdriven asshowninaFigs. 1A,; or, by the iibackpiate. Iii-order that both; embodimentamay :;be illustrated, a backpla-te 24ris1shown in:Fig.:f6

carrying .gaisheaver .42 driven by ;a help [9 and emotor;'2l,; fig; .8. vTlhe backplate' Mflis. mounted .,onfantisfrictionbearings-:51:inrthe body. ill. ,If -d ednbutrnot essentially, center of; the back- 159513131793 2,4";.:may.-.-:be; located slightly to, the :left of the center of the work in Fig. '7. ihis eccentric -arriountirigalsotends -to .;h0ldthe workydown in :the support; 92- vhenj the back-plate 2 3' and work 8 51 rotategin? theg direction; of: theiarrow. 1 However, .-,.beoause the rolls are usually sufficient to hold .the.-work..;down-.on 'thesupport, it is ordinarily preferable tomount the backplate concentrically with -the work in order thattherebe no sliding betweenw them, the; friction of rest allowing the I -;backplate;to exert; greaterrotative force on the With this. combination .of support and;v back- 4 plate. and its arrangementwith respect .to: the

the. backplate' is .usedtoqclrive the -:-=the:work;,-sothat the wheel EJmay be fed against -.;the work with great forcewithout lifting the work out: of the support -9. Rol1s-r43;.and M are each carried on a lever 45, one of which-is, behind the other; in Fig. i 6. v The levers are pivoted at 4| :and; each carries a pinditcontactinga cam ,or wedse urfaces w on one o1"-the-slidingbar tn and: 5 I which are urged by springs 52 toward the left, causing the rolls 43*and 44 to be held-against the workpieces 8 audit.

1 The springs 52 -may be comparatively ,light, ;.their function being. to. move the cam surfaces '48 interposition to resist lupwardsmovementof the :work and rol1sz4i3-and l4 withoutcreating excessive ,-ifriction:;hetw.eenthe work and isupport l. The angle of, the cam or wedge surfaces may ,.-be.:sochosen that'when rolls 43-and A ia-move downwardthey will -exert' a force much smaller than .that required --to. move them upward, in iact,,these cam-torwedge-surfaces may bezmade .--ir-reversible. It willbeseenthat similar results ;-na aybe obtained witirany-type of cam surface .;inciuding screw'threads.

For loading, fiuid pressure mambeadmitted to the leftend of "a ,cylinder- 2 5 by avmanuall voper- -watedvalve 60? pushing a piston assembly-29 to ,bars :and' I to t the rig-ht compressing the -springs:.52:and;moving the cam surfaces =48 away from" the pins 49, .--allowing the levers 45 to be raised by-the-springsfi li lifting the rolls 43 and =44.clearofthework.

9n each .bar- :50 and 5| are two. inclined sur- ,.faces. 62* whichy-when-the bars are pushed toward the right as viewed in Fig. 6, push pins 63:, against 65 ;:arms' 13,. I3, M and Mj'moving the rolls I I,-ll, l2-and i2aaway fromthe work. vThefinished work may now be removed manually-and replaced by unfinished work. Rotating the backplate 24' -willtrotatethe workpiece 8 1pressed against it 7 and worlmiece; 8' will rotate the .workpiece X 8. The rotation of the work will rotate theskewed .rol-ls Hyli', l2 and l2 whicheen a eq-the work and the rotation of these rollsforcesthe work againstthe backplate. 75. :lmonothcn einbodirnent v ot-th-is invention il-lu s- 7 trated' in Figs. 9 and 10, the work 8 may be held against a driven backplate 24" by two rolls 04 which engage an end surface of the work. The axes of the rolls 64 are offset from the axis of the work. If this offset is toward the left, as shown in Fig. 10, and the work is rotated by the backplate in the direction of the arrow, the action of rolls 64 is to force the work downwardagainst the support 9. This comes about because the motion or the end surface of the work at its line of contact with each of the rolls 64 has a small upward component, that is, the work must slide upwardly across each roll, since the surface of the roll moves horizontally, and

this sliding produces a downward force on the work.

The rolls 64 are carried by a yoke 65 on a bar 66 fastened in a block 01 fulcrumed at 08 in a bracket 09 attached to the body ID. The bar 66 may be swung by pressure means, such as a fluid cylinder 10, to force the rolls 04 against work 8. A spring ll swings the bar 06 to separate the rolls 64 from the work when pressure is released from the cylinder 10 to permit loading.

The backplate 20" is mounted as shown in Fig. 2 being located axially, but not radially, by a fiatplate ball thrust bearing 54". The weight of the backplate 24" is taken on spring pressed pins 55 as shown in Figs. 2 and 5 engaging a surface 51 on a race of the bearing 54 and holding the backplate substantially concentric with the sup port 9", except when moved away from this location by the work.

The backplate 24" is shown in Fig. 9 driven by a sheave I2 which rotates on a ball bearing 13 carried on a bushing I4 on a cylinder 15 mounted on the body I0. The sheave 12 is rotated through a belt and a motor not shown, and has internal gear teeth I0 which drive one end of a floating gear 11, the other end of which drives the backplate 24" by internal gear teeth '18 therein.

This construction allows the backplate 24" to drive work held against it, without tending to move the work away from its center of rotation as fixed by the support 9". Since there is no sliding between the work and the plate, the coefficient of friction is high and wear is minimized.

When the rolls 60 are swung away from the work, as has been described, the work may be ejected conveniently by applying fluid pressure to the left end of the cylinder 15 pushing a piston 2]", rod ejector plate 25" and work 8 toward the right.

In another embodiment, shown in Figs. 11 and I2, rolls or discs I00 are provided to engage an end surface of the work 8 and to force the work against a revolving backplate IOI. By making the rolls I00 comparatively thin discs and by placing their axes at an acute angle to the axis of the backplate, as ShOWIL'OI parallel to the axis of the backplate, it is possible for the wheelhead 3 to approach the work 8 closely, minimizing the length of the overhung portion of the wheel spindle I.

The support shoe 9 may be located as desired, but it is shown so located as to provide support for the work directly in line with the direction of feed.

One of the rolls I00 may be driven by a belt on a sheave 102 in a direction to urge the work against the support 9" or the backplat |0I may be driven by a belt on a sheave I03, or both driving means may be used.

Each of the rolls I00 has a stem l00a' slidably mounted in a sleeve I00b which is journalled in bearings I04 in a housing I05. A spring I'0'l in each sleeve l00b pushes against the hubs of sheave I02 and sleeve I002), urging the rolls I00 against the work. Housings I05 are connected by a plate I06.

Another modification is shown in Figs. 13 and 14 in which the work is located radially both by a fixed concave support 209 and by a radially fixed but rotatable solid slow roll 2I5 on a shaft .211 which may be driven as by a pulley 2I0 on the opposite end of the shaft 2 I1. The work 208 is urged against the fixed support 209 and the roll 215 by a pressure roll 220 on a spring urged arm 22 I. The fixed support 209 is located to support the work in line with pressure from the grinding tool 200. The work 208 is supported axially by a backplate 240 similar to others hereindescribed. Either or both of the rolls H5 and 220 may be skewed to force the work against the backplate 240. A driven backplate may be substituted for drive means for the roll 2I5 in order to drive the work 208.

A still further modification of the invention is shown in Figs. 15-17 in which a workpiece 308 is held by a pressure roll 320 which may be skewed, mounted on a spring arm 32 I, against a fixed concave work support 309 of the type previously described herein. The workpiece 308 abuts against a backplate 324. A permanent magnet 325 is mounted in the backplate spindle 326. The fixed support 309 is comprised of non-magnetic material such as boron carbide. The workpiece 308 may be driven either by the pressure roll 320 or by the backplate 324 or by both, as illustrated, through pulleys 322, 321 and belts 328, 329 connected respectively to a drive motor 330, as seen in Fig. 1'7. The magnet 325 establishes a magnetic circuit including the backplate 324, the workpiece 308 and the pressure roll 320 thus increasing the friction between the workpiece and the parts which drive it, and improving the characteristics of the means for driving the workpiece 308.

I claim:

1. In an internal grinding machine for refining an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution, and in combination, means to rotate the workpiece, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufficiently to bridge irregularities thereon and to position the rotating workpiece radially, a grinding tool applicable to said workpiece to refine said inner surface, rotating end stop means abutting the workpiece preventing its axial movement in one direction, and pressure means independent of said end stop means engageable against and located by the workpiece to hold it against said support means and against said end stop means.

2. In an internal grinding machine for refining an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution, and in combination, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufficient toposition the workpiece radially, a grinding tool applicable internally of said workpiece to refine said inner surface, rotating end stop means abutting the workpiece preventing its axial movement in one direction,

yieldably mounted roll means engageable against said outer surface holding the workpiece against said support means, means to urge the workpiece work support means having'an 'arcuateconcave surface generally conforming with said outerpreformed surface and extending'i'circumferentially" in contact therewith sufficiently to position the workpiece radially, a grinding tool applicable internally of said workpiece to refine said inner surface, rotating end stop 'm'eans abutting ,the'

workpiece preventing its axial movement inone direction, yieldablymounted roll means engage able against said outer surface holding the work? piece against said support means, means tourge I the workpiece against said end-stop means,.means to rotate the workpiece in said support means,

and means to retract the roll means "from the" workpiece after completion of a finished work:- piece.

4. In an internal 'grinding machinefor refine ing an inner surface-of revolution of a workpiece, said workpiece having an outer preformed surface of revolution, and in combinatiomfixed work support means having an arcuate concave'surface' generally conforming with said outer preformed surface and with which said'outer' preformed sur-'- face is enageable, said support'means extending cir'cumferentially in contactwith'said outer surface suiiiciently to position said workpiece radially, a grinding tool applicable internally to said workpiece to refine said inner; surface, rotating end stop and workpiece drive" means abuttingthe workpiece preventing its axial movement in one direction, roll means en'gageable against said outer surface holding the workpiece against said support means, and means urging the workpiece against said drive means thereby; rotating. the workpiece'in said support means.

5. In an internal grinding machine for generating an inner surfaceof revolution of a work-- piece, said workpiece having an outer preformed surfaceof revolution,-and in combination, fixed work support means having an'arcuate concave surface generally conforming with" said: outer preformed surface and with which said outer preformed surface is engageable, agrinding'tool' applicabl internally of said workpiece to generate said inner surface,end stop means abutting? the workpiece preventing its axial movement in one direction,- a pair of skewed rolls engageable against said outer surfaceholding the workpiece against said support-means and said endstop means, means to rotate the workpiece in said support means and means to separate the rolls I one direction, a pair of skewed rolls ieng-ageable;

against said outer surfaceholding theworkpieee againstsaid support means andssaid end-stop; means, meansato-rotatethe-workpiece in saidsupport means and means-to separate-onerous? after completion of er-finished workpiece and then to eject finished workpieces;

7. In-an-internaL grinding machine-for generating an-inner surface of revolution of a work-- piece, said workpiece having an outer preformed surface of-revolution, and in combination, fixedwork support means having an: arcuateconcave surface generallyconformingxwith said outerpreformed-surface andi'witd which said outer preformed surface -is-engageable,- a grinding tool applicable' 'internally of saidworkpiece to gen-- erate'said inner--surface,-endstop means abutting thei'workpiecepreventing-its axial movement inonedirection, a pair of skewed rolls engageable againstsa-id outer surface holding the workpiece against said support means and end'stopmeans,

and means to rotate at least one of said skewed rolls thereby rotating the workpiece in said-support means:

an inner surface-of revolution of a.-wcrkpiece,-said workpiece having anouter preformed surface of revolution, andin-combination, fixed worksup port means having an arcuate-concave surface; generally conforming with said outer preformed surface and extending circumferentia-lly in contact therewith sufficiently to bridge irregularities abutting the workpieceandadaptedto fix'the plane of its end surface, means tO'hOld thework piece 'againstsaid 'backplatepa pair of rolls. engageabl'eagainst said outer surface, and meansto rotatesaidErolls one at a different peripheral speed than that of the other, said rolls-thereby driving said workpiece and 1 urging it against said support meansz 10. In aninternal grinding machine for refining an inner surface of revolution ofaworkpiece,

said workpiece having anouter preformed surface;

of revolution, and in combination, means to rotate the workpiece, fixed work support means having'an arcuate concave surface generally con forming with said outer preformedrsurfac i and extending circumferentially in contact therewith sufliciently to bridge irregularities thereon and to position the rotating; workpiece radia11y,;agrinding tool; applicable to said workpiece I to 'refine said inner surface,- rotatingend stop means abutting the-workpiecepreventing its axial moyeagainst theworkpiecebybalanced pressure means. 7

11.. In an internal grinding machinezfor gen-- erating an inner surface of revolution of awcri i 8. In an internal-grinding machine forgencrating an'inner surface'of revolution-ofa worka piece,- said workpiece-havinganouterpreformed I surface of revolution; and incombination, 'iixede work support means havingan arcuate concave sur-face generally conforming with said outer-preformed'surface and with which saidouterpre formed 'surface I is engageable, a grinding tool. applicable internally of said workpiece "to gen i crate said inner surface; a rotatable-end-rstop .abutting the workpiecepreventing its axialmovementwin one directiomwapair of -skewed rolls engageable against said outer surface holdingthe workpiece against" said: support and end-stop me'ansandmeans to drive said end stop thereb rotating said workpiece in'saidsupportn 9. In an internal grindingmachinefor refining piece, said workpiece having an outer preformed surface of revolution, and in combination, fixed work support means having an arcuate concave surface conforming with said outer preformed surface and with which said outer preformed surface is engageable, a grinding tool applicable internally of said workpieces to generate said inner surface, a platen abutting the workpiece adapted to fix the plane of rotation thereof, roll means engageable against said outer surface holding the workpiece against said support means, nonreversible means urging said roll means against said workpiece and preventing movement of the roll means away from said support means, means to urge the workpiece against said platen, and means to rotate the workpiece in said support means.

12. In an internal grinding machine for generating an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution, and in combination, fixed work support means with which said outer preformed surface is engageable, a grinding tool applicable internally of said workpieces to generate said inner surface, a platen abutting the workpiece adapted to fix the plane of rotation thereof, roll means engageable against said outer surface holding the workpiece against said support means, non-reversible means urging said roll means against said workpiece and preventing movement of the roll means away from said support means, means to urge the workpiece against said platen, means to rotate the workpiece in said support means, and means to withdraw the roll means after operation of the tool to permit replacement of a finished workpiece.

13. In an internal grinding machine for generating inner surfaces of revolution having the same diameter in a plurality of workpieces having outer preformed surfaces of revolution of different diameters, and in combination, a grinding tool applicable internally of said workpieces, fixed work support means having an arcuate concave surface approximately conforming with said outer preformed surfaces and with which a plurality of said outer preformed surfaces are engageable, said support means being adapted to locate said plurality of workpieces radially with their centers of revolution substantially equidistant from the line of contact of said wheel, end stop means abutting one of a plurality of adjacent workpieces preventing their axial movement in one direction, roll means engageable against each of said outer surfaces holding the workpieces against said support, irreversible friction means urging said roll means against each said workpiece and preventing movement of the roll means away from said support, means to urge the workpieces against the end stop means, and means to rotate the workpieces in said support means.

14. In an internal grinding machine for generating inner surfaces of revolution having the same diameter in a plurality of workpieces having outer preformed surfaces of revolution of different diameters, and in combination, a grinding tool applicable internally of said workpieces, fixed work support means with which a plurality of said outer preformed surfaces are engageable, said support means being adapted to locate said plurality of workpieces radially with their centers of revolution substantially equidistant from the line of contact of said wheelyend stop means abutting one of a plurality of adjacent workpieces preventing their axial movement in one direction, roll means engageable against each f 12 said outer surfaces holding the workpieces against said support, irreversible friction means urging said roll means aaginst each said workpiece and preventing movement of the roll means away from said support, means to urge the workpieces against the end stop means, means to rotate the workpieces in said support means, and means to withdraw the roll means after operation of the wheel to permit replacement of finished workpieces.

15. In an internal grinding machine for generating an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution and an end surface, and in combination, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufiiciently to bridge irregularities thereon, said support means thereby fixing the rotating workpiece radially, a grinding tool applicable to said workpiece to generate said inner surface, rotatable end stop means abutting the workpiece preventing its axial movement in one direction, means to rotate the end stop means and thereby the workpiece, and pressure means having roll means engaging an end surface of said workpiece and holding it in frictional engagement with said end stop means, the axis of revolution of said roll means being displaced from the axis of revolution of said workpiece, said pressure means thereby also urging said workpiece against said support.

16. In an internal grinding machine for refining an inner surface of revolution in a workpiece having a preformed outer surface of revolution, and in combination, a rotary tool applicable to said inner surface, a rotating platen adapted to fix the plane of an end surface of a workpiece in frictional contact with said platen and to drive said workpiece, support means having a stationary arcuate surface extending circumferentially in contact with said outer surface sufficiently to fix the location of the workpiece in the plane of said platen, and roll means engageable with an end surface of the workpiece to hold it against said platen, the axis of revolution of said roll means being displaced from the axis of revolution of said workpiece, whereby the workpiece is urged against said support.

17. In an internal grinding machine for refining an innersurface of revolution of a workpiece, said workpiece having an outer preformed sur face of revolution, and in combination, means to rotate the workpiece, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufficiently to bridge irregularities thereon and to position the rotating workpiece radially, a grinding tool applicable to said workpiece to refine said inner surface, a rotary backplate mounted with sufiicient radial play to allow it to be positioned radially by said workpiece, said backplate being adapted to position said workpiece axially and angularly, and pressure means independent of said backplate adapted to engage and to follow said workpiece, holding it against said support means and aaginst said backplata 18. In an internal grinding machine for generating an inner surface of revolution of a Workpiece, said workpiece having an outer preformed surface of revolution and an end surface, and in combination, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufiiciently to bridge irregularities thereon, said support means thereby fixing the rotating workpiece radially, a grinding tool applicable to said workpiece to generate said inner surface, rotatable end stop means abutting the workpiece preventing its axial movement in one direction, means to rotate the end stop means and thereby the workpiece, and roll means engaging an end surface of said workpiece and holding it in frictional engagement with said end stop means, the axis of revolution of said roll means forming an angle of less than 90 with the axis of said end stop means. v

19. In an internal grinding machine for generating an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution and an end surface, and in combination, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith suificiently to bridge irregularities thereon, said support means thereby fixing the rotating workpiece radially, a grinding tool applicable to said workpiece to generate said inner surface, rotatable end stop means abutting the workpiece preventing its axial movement in one direction, means to rotate the end stop means and thereby the workpiece, and roll means engaging an end surface of said workpiece and holding it in frictional engagement with said end stop means, the axis of revolution of said roll means forming an angle of less than 90 with the axis of said end stop means, and means for rotating said roll means and thereby urging said workpiece against said support means.

20. In an internal grinding machine for generating an inner surface of revolution of a workpiece having a preformed outer surface of revolution and an end surface and in combination, fixed work support means having an arcuate concave surface substantially conforming with said outer surface and extending circumferentially in contact therewith sufficiently to bridge irregularities therein and to fix the center of rotation of said workpiece, a backplate adapted to fix the plane of the end surface of a workpiece abutting said backplate, means for forcing said workpiece against said backplate, means for rotating said workpiece, roll means and positioning means for moving said r011 means into contact with said outer surface, said positioning means being adapted to exert only a comparatively light force when said r011 means moves toward th workpiece and being adapted to resist with comparatively great force motion of said roll means away from said workpiece, thereby preventing said workpiece from being moved away from said support means by force exerted by said tool.

21. In an internal grinding machine for refining an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution, and in combination, means to rotate the workpiece, fixed work support means having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufficiently to bridge irregularities thereon and a grinding tool applicable to said workpiece to refine said inner surface, said support surface including a hole through which fluid may be forced to reduce the friction between said workpiece and said support.

22. In an internal grinding machine for refining an inner surface of revolution of a workpiece, said workpiece having an outer preformed surface of revolution, and in combination, work support means including a fixed support having an arcuate concave surface generally conforming with said outer preformed surface and extending circumferentially in contact therewith sufliciently to bridge irregularities thereon, said fixed support being comprised of non-magnetic material, rotatable end stop means abutting the workpiece, rotatable pressure roll means engagable against said workpiece to hold it against said support means, means connected to one of said rotatable parts to driv said workpiece and a permanent magnet connected to establish a magnetic circuit in said end stop means and through said workpiece and pressure roll means thereby increasing the friction between said end stop means, workpiece and pressure roll means.

HAROLD L. BLOOD.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,027,627 Blood et al Jan. 14, 1936 2,032,269 Einstein et a1. Feb. 25, 1936 2,047,055 Blood July 7, 1936 2,107,051 Briney Feb. 1, 1938 2,243,371 Blood May 27, 1941 2,264,179 Johnson Nov. 25, 1941 2,440,148 Madison Apr. 20, 1948 2,478,607 Theler et a1. g Aug. 9, 1949

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