US1733086A

US1733086A - Centerless grinder

Info

Publication number: US1733086A
Application number: US463892A
Authority: US
Inventors: Sobolewski Edward
Original assignee: Cincinnati Grinders Inc
Current assignee: Cincinnati Grinders Inc
Priority date: 1921-04-23
Filing date: 1921-04-23
Publication date: 1929-10-22
Anticipated expiration: 1946-10-22

Description

Oct. 22, 1929,.

E. SOBOLEWSKI CENTERLES S GRINDER med April 25. 1921 a sheets-sheet 2 INVENTOR.

da/ww( 237m' ATTORNEY.

8 Sheets-Sheet 3 swg( JNVENTOR.

7 ATTORNEY'.

Filed April 23. 1921 Oct 22, 1929- E. soBoLEwsKl CENTERLESS GRINDER Filed April 23, 1921 8 Sheets-Sheetl 4 0 01 M 0l Ww 8 sheets-shed@ INV EN T 0R.

f f l f oct. 2z, 1929,.

Oct, 22, 1929. E. soBoLEwsKl I cENTERLE'ss GRINDER 8 Sheets-Sheet '7 Filed April 23, 1921 INI/EN TOR.

A TTRNEY.

Y ing of the work on centers, or the Patented Oct. 22, 1929 UNITED STATES PATENT ori-ICE EDWARD SOBOLEWSKI, 0F DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TO CINCINNATI GRINDERS INCORPORATED, 0F CINCINNATI, OHIO, A CORPORATION Application inea April 23,

This, invention relates to grinding apparatus. 1,.

\ One of the objects lof, this invention' 1s to provide a grinding apparatus of thoroughly rug ed and practical construction, highly eiiclent action, and well adapted to meet certain peculiar conditions met with 1n practical use. Another object of this invention is to provide a grinding apparatus in which work pieces may be rapidly and with a high degree of precision ground to true round cross-section without necessitating the mountlike, and to provide such a grinding apparatus in which control of the rotation of the work, while a grinding wheel performs a grinding operation thereon, is positive and uniform and may be made to take place, in accordance with certain preferred features of my invention, bot-h before and after the grinding operation by the grinding wheel commences. Another object is to provide an apparatus of the abovementioned character in which a work-rota- .tion-controlling wheel is so positioned with respect to the grinding wheel, preferably underneath the grinding wheel, so as to achieve certain important actions contributed by the effect of gravity on the work. Another ob-l 'ject of this invention is to provide a grinding apparatus of the above-mentioned character in which a feeding action by the work-rotation-controlling wheel may be depen'dably and reliably achieved, both before and after, las well as during, the grinding operation on the work by the grinding wheel. Another object, more specifically, is to provide a grinding apparatus in which the work-rotating Wheel is of greater width of operative face than the grinding wheel so as to achieve cerv tain important advantages in both the control of the rotation and axial feeding movement of the work, either before or after, or both before and after, the` grinding operation on the work by the grinding wheel.- Another object is to provide a grinding apparatus of the above-mentioned character in -which the two wheels and related partsare so related -to Veach other that the effect of gravity on the work may be dependably and efliciently CENTERLESS GRINDER 1921. Serial No. 463,892.

utilized in insuring effective work-rotating contact and work-feeding contact between the work and the work-rotating wheel, particularly before and after the grinding operation on the work by t-he grinding wheel. l,

Another object is to provide a grinding machine of the above-mentioned character in which rotation and feed of the work may be effectively achieved without depending upon the thrust of the grinding wheel for urging and holding the work in effective operative contact with the work-rotating and feed wheel. Another object is to provide an apparatus of the above-mentioned character in which rotation of the work prior to its entryl into contact with the `gr1nd1ng wheel, and also after leaving contact with the grinding, wheel, may be dependably achieved in a simple and thoroughly practical manner. Another object is to provide a construction of the abovementioned character in which starting of the rotation of the work by the work-rotating wheel may be achieved without depending upon the grinding wheel to force the work into work-rotating contact with the work-rotating wheel, so that the workrotating wheel already has control of the rotation of the work before the latter` contacts with the grinding wheel.

Another object of this invent-ion is to provide a compact and practical driving arrangement for the work-rotating wheel well adapted for simple and rapid manual control to give the work-rotating wheel the necessary very slow speed for controlling the rotation and feed of the work or for giving the work-rotating wheel a relatively'much higher speed when it is desired to true the wheel. Another Objectis to provide apparatus of the above-mentioned character inv whichv control of the relative positions and relations of the two wheels maybe manuallyv effected in athoroughly' practical, simple and rapid manner. An-

other object is to` provide a thoroughly practical and dependable means for holding work of round section between the grinding wheel and the work-rotating Wheel while permitting axial movement Y and convenient mechanism for predetermining ythe relation of the work-holding means to the work and to the wheels;

Another object is to provide a grinding' apparatus in which the work-rotating and feed .wheel is positioned below 'the rinding wheel and to provide rugged, e cient and dependable supporting, control, and drive arrangements for the two wheels, and to provide an apparatus having the workrotating` wheel positioned below the grinding wheel that will be well adapted to meet the varying conditions of hard practical use and well adapted for rapid, efficient and high precision grinding on a large scale. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combination of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the .following claims. l

In the accompanying drawings, in which is shown a preferred embodiment of this invention,

Figure 1 is a right side elevation of thegrinding apparatus in assembled relation,

the lower portion of the apparatus being omitted;

Figure 2 is an elevation as seen from the left of Figure 1;

Figure 3 is a lan view on an enlarged scale of the wor -holding mechanism and certain of the control mechanism therefor, and of the wheel truing mechanism;

Figure 4 is a vertical sectional view on an enlarged scale taken along the` line 4 4 of Figure 3;

Figure 5 is a vertical sectional view on an enlarged scale as taken along the line 5-5 of Figure 3; y

Figure 6 is-a verticalsectional view on an enlarged scale taken along the line 6 6 of Figure 3;

mechanism therefor, the .iframe of the ma' 4chine being understood to be removed;

Figure 8 is a vertical sectional view, on an enlarged scale, taken substantially through the axis ofthe lower or workrotating and feed wheel, showing the mounting and support and control therefor of the work-rotating and feedfwheel, and showing I also the speed-change drive mechanism for the latter.;

Figure 9 is a horizontal sectional view on an enlarged scale taken substantially through the 4horizontal axis of the handA wheel of Figure`8, showing certain details of the mechanism for raising and lowering the work-rotating and feed wheel;

Figure 10 is a detailed vertical sectional view taken along the lin'e 10--10 of Figure 9 5 Figures 11 and 12 are vertical sectional views taken along the 'lines 11-1f1 and 12-12 respectively'of Figure 8;

Figure 13 is a perspective view of one of the work-holding members which hold the work between the two wheels, and

Figure 14 is an elevation of part of the wheel-truing mechanism.

Similar reference characters refer to similar parts throughout the several'views of the drawings.

Referring now to the drawings and more. particularly to Figures 1 and 2, there is provided a main frame 1, having a suitable hori-l zontally extending base, only a portion of which is shown in the drawings, and having an upper portion extending to the left, as viewed in Figure 1. In this upper overhanging portion of the frame 1 there is supported in suit-able bearings a spindle or arbor 2 carrying at one end thereof (the right-hand end, as viewed in Figure 2) a grinding wheel 3 and carrying at the other end thereof the left-hand end, as viewed in Figure 2) a pulley 4 over which'runs the driving belt 5, connected to any suitable source of power, for

grinding speed. l

As will be clear from Figures 1 and 2. there is positioned and rotatably supported underneath the grinding wheel 3 a wheel 7; one of the distinguishing features of this invention lies in thev construction, relative arrangement, and drive of this wheel 7', and' it may here be noted that the work A, interposed between the two wheels, will be seen to be physically supported on the wheel 7. TheA wheel 7 may be termed a work-supporting wheel, but in view of its primary function in controlling the rotation of the work A, all as hereinafter described in detail, I prefer to term it a work-rgtatin o r regulating wheel. 'Ifhe wheel 7, p'efera ly of abrasive material, is preferably of less diameter than the upper or grinding wheel 3 and in accordance With-certain distinctive features of this invention, the regulating wheel 7 is made'of sufficient length (axially, as viewed in Figure 2, and with respect to the width of the driving the grinding wheel `at a suitableA operative face of the grinding wheel 3) to `support the work A before, during, and after coming into contact with-the grinding wheel 3. According to another distinctive feature of this invention, as hereinafter made clear, the wheel 7, because of this relative dimension with 4respect to the grinding wheel face, also rotates the work positively and uniformly andeffects an' axial feeding movement of the work before, during, and after the work is in contact with the grinding wheel 3.

The wheel 7 is preferably so positioned that its axis (assuming its axis and the axis of the peripheral grinding wheel 3 to be parallel) and the axis of the grinding wheel 3 are in the same vertical plane; this preferred relation is clearly shown in Figure 1. The work-rotating wheel 7, however, is

mounted so thatits spindle 9, together with the wheel 7, may be swung out of parallelism with the axis of the grinding wheel and, more particularly, so that the axis of the work-rotating wheel 7 will be' at an appropriate but relatively small angle'to the axis of the vwork A which is preferably held, by means more fully describedbelow, so that the axis of the work A is substantially parallel to the axis ofthe peripherally operative grinding wheel 3. Preferably, also, the axes of the two wheels, where they operate by way of their peripheries, as is illustrated in the preferred embodiment shown in the drawings, are in horizontal planes. The above-described angular relation of the axis of the work-rotating wheel 7 to the axis of the work A achieves a feeding movement of the work A in an axial direction, as will be made more clear hereinafter. r

Considering more in detail the mounting of the work-rotatingiwheel 7 it may first be noted that the base portion of the frame 1 has an upstanding hollow pedestal 10 (see Figure 8) positioned substantially underneath the grinding wheel 3; the pedestal 10 is bored out to receive a cylindrical ram 11 having a table 12 formed at'its upper portion. 'To the table 12 is secured a frame 42 spect to the bearing 44 in the frame 42. lA

pulley 46 (Figure 8) driven by abelt 47 (Figure .2) from any suitable sourcel of power drives the spindle 9 and the wheel 7 but through mechanism, more clearly described hereinafter, whereby the' wheel 7 is rotated comparatively slowly during the operation of the apparatus but at quite high speed while the wheel 7. is being dressed or trued.

The wheel 7 may be moved toward or away from the grinding wheel 3 by raising and lowering it, the ram 11 sliding vertically within the pedestal 10. A screw 13 (Figure 8) extends downwardly into a rigidly supported nut (not shown) carried in the base portion of the machine, and the upper portion of the screw 13 is so secured to thet table 12 and ram 11 that the up ordown movement of the screw 13 is communicated to these parts -eCured to the upper end of the screw 13'is a wormwheel 16 (Figures 8 and 9) the upper end of the screw 13 being rotatably supported in the table 12 by means of a bearing 17. worm 18 meshes with the worm wheel 16 and is carried by a shaft- 19 which is rotatably and slidably supported in the bearings 20 (Figure 9) carried by the table l2. To the shaft 19)is also secured a gear 22 (Figures 8, 9 and 10 The shaft 19 extends outwardly through the side of the table 12, the latter being formed with a tube-like extension 23 through which the shaft 19 passes. Interposed between theshaft 9-and the sleeve 23 and rotatable with respect to both isa sleeve 24. The righthand end of slee-ve 24 has secured thereto a grad-v uated hand wheel 25 and its left-hand end, as viewed in both Figures 8 and 9, has secured thereto a gear 26. -Gears 22` and 26 are positioned adjacent each other and will be seen to be coaxially mounted, gear 22 being rotatable with the shaft 19 and gear 26 being rotatable withthe sleeve 24, the latter being rotated manually by the hand-wheel 25.

bearing bushing 35 may be interposed between the sleeve 32 and the shaft 31 (Figure 10) The outer or right-hand end of the sleeve 24is formed withv clutch teeth 27 (Figure 8) and at the outer end of the shaft 19, which, as above noted, is axially slidable,is secured a knob 29, the inner or left-hand end of 'which has formed thereon clutch teeth 28adapted to interengage with the clutch teeth l27 when the knob 29 and the shaft 19 are moved to the left,

as viewed in..Figure.8, or to be` disengaged therefrom, when the parts are in the position shown in Figure.

When it is desired to raise or lower vthe regulatingI wheel 7 so as to change the distance between the adjacent operative surfaces Iof the two wheels for accommodating work of different diameter, the movement ofthe wheel' in a vertical direction may be effected rapidly by pulling the knob 29 toward the right, as

viewed in Figures 8 and 9, thus to disengage the clutch 27-28; the resultant axial movement of the shaft k19 in a direction toward the right, moves the gear 22 into engagement with the gear 33. The subsequent manual rotation of the hand Wheel 25 causesthe rotation of the shaft'19 and\o`fy the worm 18 .through gear 26, gear 34, gear 33, 4and gear 22, the ratios of drive of these gears being`v such as to greatly multiply or increase the speed of rotation of the shaft 19 and worm v 18 with respect to the rate of rotation of the y vwill be turned four times as fastA as the hand wheel 25.

Thus, very rapid manual movement of the one wheel toward or away from the other may be effected.

However, when it is desired to make a fine and relatively precise adjustment of one wheel toward or away from the other, the knob 29 is ushed inwardly or to the left, as viewed in

gures

8 and 9, whereupon the clutch teeth 27 and 28 interengage'and the gear 22 is moved to the left out of meshing engagement with the gear 33. The speed-increasing gearing is thus cut out of action and the shaft 19, through the clutch 27-28, is thus directly connected to the hand wheel thus, the Worm 18 may be directly rotated manually by the hand wheel 25, and due to the speed ratio between the worm 18 and the worm wheel 16, a' far greater rotative movement of the hand. wheel 25 is necessary to raise or lower the regulating wheel 7 than was the case when the speed-increasing

gearing

26, 34, 33 and 22 was inaction. Suitable graduations on the hand wheel thus permit fine adjustment of the distance between the two wheels and in fact an accuracy of adjustment up to one-fourth of one-ten-thousandths of an vinch may be achieved. The screw 13, which meshes with the nut (not shown) fixedly carried in the base ofthe pedestal 10, is always under compression, due to the fact that the weight of the ram 11 and t-able 12 and of the parts carried thereby is transmitted to the nut through the screw 13; thus, all lost motion is always taken up. It might further be noted that the screw-threaded engagement between the screw 13 and the nut contributes toward effecting a relatively large angular movement of the hand wheel 25 for a given vertical movement of the wheel 7.

The upper end of the pedestal' 10 is flanged, as at 14,\and resting upon the upper face of the flange 14 is a collar 37 (Figure 8) which is splined to the cylindrical ram 11, by means of a short key 36, so that the collar 37 and ram 11 (the latter with the parts carried thereby) must turn together when swungl about a vertical axis. The collar 37 is 'provided with arcuate slots 38, shown in dotted lines in Figure 9, and passing through these slots are cap. screws 39 for clamping the collar 37 to the pedestal 10. When it is desired to achieve an angular relation between the axis of the work-rotating wheel 7 and the axis of the work A, in order to achieve an axial feeding movement of the worlnthe cap screws 39 are loosened up and the table 12, frame 42 carrying the wheel v7, and the ram11', Aare turnedzabout a vertical axis through the desired relatively small angle, all within the limited range permitted by the arcuate slots -the eccentric 38. The collar 37 of course turns with the ram 11 and, as indicated in Figure 1, the collar 37 may be provided with graduations to determine visually the angular relation achieved between the axes offthetwo wheels. In Figure I-1 the graduations indicate a zero angle.

The upper end of and after the desired adjustments of lthe regulating wheel have been achieved, all as above described in detail, a screw clampopthe pedestal 10 is slotted erated by a handle 15 (Figure 9) acts to naring of the regulating'wheel 7, reference may again be made to Figure 8 in which is shown a casing 48 attachedto the left-hand portion of the frame 42 by means of screws 5l; this casing 48 encompasses the pulley 46 but suitable openings are provided therein to permit the belt 47 to `pass around the pulley (see .Figure 2). Within this casing 48 is housed and mounted the speed-change mechanism for giving the regulating wheel 7 the preferred alternative speeds above-mentioned.

This speed-change mechanism includes an internal gear 49 (see also Figure 11) -nonrotatably and fixedly mounted within the casing 48, as will be clear from Figure 11. A pinion 50 meshes with this internal gear 49 and is rotatably mounted on an eccentric 51 which is preferably formed integrally with the pulley 46. Pinion 50 is greater width in an -axial direction than is the internal gear 49 and is of appropriate width so that it may also' mean with an internal gear 66 formed 1n the enlarged cylindrical portion 65 of a sleeve member 62 rotatably supported in the bearing 64 forming the left-hand end closure for the casing 48. The number of Vteeth of the internal gear 66 is less than, preferably by one or two teeth, the numberof teeth 67 Von the internal gear 49.

A sleeve 58 extends into the sleeve 62 and is splined to the shaft o'r spindle 9 by means of the key 57 and keyway 56, so that the sleeve 58, to the outer end. of which is secured the hand Wheel 59, may be axially moved relative to the spindle 9, though necessarily rotating together. The inner or right-hand end of sleeve 58 is toothed as at 69, and the toothed portions 69 may mesh or interlock with either the teeth 68 formed in the left-hand face of portion 52 of the pulley 46 or with the teeth 70 formed on the inner or right-handend of the sleeve 62, depending sleeve 58 is moved to the left and its clutchupon whether the sleeve 58, by means of the iand wheel 59, is moved to the right or to-the The spindle 9 carries an outwardly'sprin pressed ball 60 adapted to coact with suitable recesses on the inner face of the sleeve 58, so as to yieldably hold the sleeve 58 and the clutch-like portions 69 iii either the neutral position shown in Figure 8 or in the abovementioned end positions to the right or to the left.

When the clutch portions 69 are in engagement with the' teeth or clutch portions 68, the spindle 9, and hence the work-controlling wheel 7 is directly connected with thepulley 46, and the spindle 9 and wheel 7 are rotated by the pulley many times as fast as when the l teeth 69 are caused to interengage with the clutch teeth 70 on the sleeve 62. In the latter position of the parts the spindle 9 and wheel 7 are rotated at a work-regulating speed through the internal gear 66, which is slowly rotated through the medium of the eccentrically mounted pinion 50, which meshes with both the gears 66 and the fixed gear 49.

At the above-mentioned high speed of rotation of the wheel 7, the latter may be dressed or trued. The ratio of the respective work-controlling and wheel-dressingspeeds I prefer to be not less than 1 to 20 and not more than 1 to 50, but these ratios may be departed from, depending upon various factors met with in practice.

`With the hand Wheel 59v andthe clutch teeth 69 in the position shown in the drawings, the drive .of the wheel 7 is halted since the clutch member 69 is in neutral position, being in engagement with neither the clutch parts 68 nor the clutch parts 70.

A collar 51a carried Within portion 65 of the rotatable sleeve 62 engages the left-hand end face of the pinion 50 and holds it in position on the eccentric 52. The parts are appropriately lubricated. For eiryample, an oil passage 53 connects the oil groove 55 with the bearing surface` of the pinion 50 andthe bearing surface of the eccentric 52, while a suitable oil cup, or the like, 63 supplies oil to the relatively rotatable parts 64, 62 and 58.

While the bearings for supportmg the spindles of the two Wheels may be of any suitable construction, I find a construction like that shown in Figure 12 desirable. A bearingcap 72 is secured to the frame 42 by cap screws 73 and grips a split sleeve 74 within which is a split bearing bushing 75 rotatably supporting the spindle 9. Along the split in the bushing 75 may be provided -a suitable number of tapered plugs 76 controlle'd by a screw 77 in the cap- 72. The tapered plugs 76 may be controlled bythe screws 77. By means orf nuts 7 5, at the left-hand thev enlarged end of the bearing (see Figure 8) the bushing may be movedendwise.

Considering now the manner in which the work-pieces are held in operative relation to the grinding wheel'3 and the workcontrol lin Wheel-7, it is first to be noted, referring to igures 1 and 5that the main frame 1 is provided with vertically extending guiding ways 80 along which is vertically slidable a carriage 86 provided with a generally horizontally extending frame-like portion carrying two horizontally spaced work-hol'd'ing members 109 which extend between the adjacent operative surfaces of the two wheels to form with the latter what may be termed a four-,sided lgrinding throat.- These parts will be described more fully hereinafter. A gib 87 (Figure 3) secured to the carriage 86 by screws 88 coacts with the guides 80.

The vertical position of the carriage 86 along the ways 80, and hence the s acing of the work-holding members 109 rom the wheels, is determlned by a mechanism better illustrated in Figure 5. Turning to Figure 5, the carriage 86 will be seen to have rotatably supported therein a screw 82 which passes through a nut 81 fixedly secured to the frame 1. A suitable bearing 94 supports the upper end of the screw 82, while keyed to the lower end thereof is a sleeve or hub 83 having integrally formed therewith a bevel gear 84, the part 83 being journaled in the bearing portion of a bracket which is secured to the lower portion 85 of the carriage 86 and which rotatably supports also a shaft 89. The shaft 89 carries a bevel gear 92 meshing with the gear 84 and at its outer end has xtending to the left, as viewed in Figure 1, and tothe right, as viewed in Figures 3 and 7, lfrom the carriage I86 and preferably intel grally formed therewith, isAWhat may be termed a guide frame formed to provide two ,y spaced guide members 95 and 96 (see Figure 6) each reinforced, to make it more rigld with res ect to the carria e 86, by inclined' bracing anges 97. The grmding wheel 3 extends between the guidemembers 95 and 96,

'the latter being joined at their outer ends by a cross-piece preferabl formed integrally therewith. -The under aces and outer side faces of the

members

95 and 96 are suitably machined to slidably receive the spaced

carriages

98 and 113, one on each side of a line joining the axes of the .two wheels (see Figure 1).

Referring to Figure 6, the carriage 95 will be seen to rest against the under faces of the

guide members

95 and 96 and is provided with the side portions 99 which have secured thereto, by the screws 102, the inwardly extending members 100 which overlap the latf a boss 103 (Figure 6) on the carriage 98, collars 105 and 106 (Figure 3), one on each side of the boss 103, being fixed to the screw 104 to cause the carriage 98 to move with the screw when thelatter moves axially as it is turned with respect to the nut 107.

The carriage 98 carries a work-holding member 109, preferably taking the form of a bar or late-like member shown more clearly in Figv re 13. The member 109 extends underneath and transversely of the spaced guiding members 95 and 96 (see Figure 3) and is secured to the carriage 98 by means of cap screws 110l which pass through suitable recesseslll (Figure 13) inthe ends of the member 109. v

As shown in the drawings, one of the longitudinal edge vfaces of the member 109 is I beveled, and asjis clear from Figure 1 of the drawings, this inclined end face is presented toward the workv A to be contacted rby the latter. f

, As the carriage 98 is adj ustably positioned along the

uiding members

95 and 96, in respohse to t e actuation of the hand wheel 108, the work-holding member 109 carried thereby is correspondingly adjustably positioned, as

will be clear from

Fi res

1 and 7.

The coacting wor -holding member,109,.

rected plate-like members 115, secured to the portions 114 by screws 102, overlapping the lateral projecting portions of the

guide members

95 and 96. Thus, the carriage 113 is slidable lengthwise of the

m'embers

95 and 96.

The carriage 113 with the work-holding members109 carried thereby may be adjust ably positioned by,` operating the hand wheel 118 (Figures 1, 3 and 7) the hand wheel 118 actuates a screw 117 which is threaded in -a nut 119 carried by or formed in the crosspiece 120 which joins the ends of the

guide members

95 and 96. The inner end of the screw -.117 passes through a boss 116 (Figures 3 and 7) on the carriage 113,

collars

105 and 106, one on either side of the boss 116 and secured to the screw 117, causing the carriage 113 to move with the screw 117 as the latter moves longitudinally during its rotation relative to the nut 119.`

The work-holding member 109 carried by the carriage 113 is of similar construction to that hereinabove described in connection the same horizontal plane and both above the center or axis of the work-A. I wish to point out, however, that this is a preferred relation of these parts with respect to uthe work and/or the wheels, but that the position thereof maybe varied, if desired. For example7 the two members 109 may be positioned in different planes as, for example, one may be offset vertically relative to the other. The end faces ofthe members 109 and which faces contact with the work preferably are shaped to be tangent to the latter, as well as inclined,

`as indicated in Figure 1,1 for example, of the drawings.

Considering now briefly the operation of the apparatus, it is first to be noted that the grinding wheel 3, as above pointed out, isro-y tated at a suitable grinding speed; the lower wheel 7, which is to control the rotation of the work A and 4to cause axial feeding movement of the work, is driven at the relatively very slow speed achieved when the hand wheel 59, sleeve 58, and clutch member 69 (see Figure 8) are moved to the left from the position shown in Figure 8. The distance between the two wheels is predetermined by manipulating the hand wheel 25 to raise or lower the wheel 7 to an appropriate position with respect to the grinding wheel 3. The carriage 86 is suitably positioned, by means of the hand wheel 93, in turn to position the work-A holding members 109 appropriately with respect to the two wheels, preferably in substantially the relative position shown int-'Figure 1. The

carriages

118 and 113, carried by the horizontal guides and 96 of the carriage 86, are suitably adjusted along the

guides

95 and 96, by means of the

hand wheels

108 and 118 respectively to space the Work-holding members 109, carried by these carriages, appropriately relative to the diameter of the work A to be operated upon. Thus, a four-sided grinding throat, made up by the grinding wheel 3, the work-controlling wheel 7, and the two horizontally spaced work-holding members 109, is preliminarily adjusted to receive the work to be operated upon. Where it is desired to cause the work A to move axially through the grinding throat, the work-controlling wheel -7 is swung about a vertical axis to provide the desired relatively small feed angle between the direction of travel of the operative surface of the wheel 7 and the path of travel of the work A, as determined by the work-holding members 109. All of the above-mentioned adjustments have been described in detail hereinabove, but it might additionally be noted that the workhoding members 109 are so related that they hold the work A with the axis of the latter substantially parallel to the axis of the grinding wheel 3. l y

The two wheels, rotating at the respective speeds immediately above pointed out, are driven so that they rotate about their axes in the same direction, as viewed in Figure 1, for example. Thus, both wheels may be made to rotate in counter-clockwise direction, the operative surface of the grinding wheel where it contacts with the work A moving toward the right, and the operative surface of the regulating wheel 7, where it contacts with the work A, moving toward the left. During the operation of the apparatus, the grinding of the work A is substantially all done by the upper or grinding wheel 3, but by making the lower wheel, that is the wheel 7, of some hard material, like a relatively hard abrasive, the grip of the lower wheel on the4 work` A insures proper rotation ofthe work relative to the grinding wheel 3 and, due to the angular relation above described, also insures positive feed, in an axial direction, of the work whether the latter is in contact with the grinding wheel 3 4 or not. Thus, I insure positive control of the rotation and feed of the work the regulating wheel 7 is in a direction from the right to the left, as viewed in Figure 2, are placed upon the right-hand projecting ,end portion of the wheel 7 and between the correspondingly projecting end portions of the work-holding members 109, the weight of the work pieces yA thus positioned being borne entirelyl by'i-the wheel 7. Due-.to these relations of the parts, the work pieces thus 'positioned are set into rotation by the wheel 7,

'any thrust on the work caused by the wheel 7 during this action being taken up by the lefthand work-holding member 109, as viewed in Figure l; at the same time, due to the angular relation above-described, the wheel 7 causes the work, while it is thus being rotated, to

move axially in a direction from the right to the left, as viewed in Figure 2. The weight of the work, being borne substantially entirely by the wheel 7, is elective, in conjunction with the low surface speed of thejregulating wheel 7, to eect such an effective contact of the work with the regulating wheel 7 that thel 'latter can readily insure proper rotation of the Work prior tothe entry of the work into contactwith the grinding wheel 3. Thus, the grinding operation to be performed by the grinding wheel 3 commences upon an already properly rotating work piece. f

The proper rotation of the work 'by the regulatmg wheel 7 continues as the latter feeds the work axially in a direction from the ri ht to, the left, as viewed in Figure 2,

until t e work is moved to the left beyond the grinding wheel 3, whence the grinding operation is finished. The left-hand portions of the work-holdig'members 109, projecting to the left of the grinding wheel 3, as viewed in Figune 2, however,still act to hold the work upon and in operative contact with the regu- Vlating wheel 7 so that the latter can continue the rotation of the work and feed it away from the grinding wheel, whence it`may be removed from the supporting wheel 7. Thus,

rotation of the work continues therefore as rection, that is, in counter-clockwise direction, as 1n Figure l, the adjacent operative surfaces of the two wheels, andto which adjacent operative surfaces the work A is presented, travel in opposite directions with respect to a point intermediate thereof.

Considering certain further actions that take place in the operation of the apparatus, it might first here be noted that, when a work piece is placed upon the projecting portion of the regulating wheel 7, the weight of the work holds it down on the regulating wheel so that the latter, with its slowly moving surface, gets a grip on the work and starts the latter rotating. If the regulating wheel is tilted about the vertical axis of the column 11 (Figure 8) so that there exists a proper feed-f ing angle between the path of travel of the operative surface of the regulating wheel 7 and the path of travel in an axial direction of the work A (the path of travel of the Work being determined by the work-holding members 109) the regulating wheel will also move the rotating work axially into contact with the grinding wheel and continue to rotate and feed the work even after the work passes out of contact with the grinding wheel. Also, if lany under-sized Work is inserted into the apparatus, the undersized work will be rotated and fed and there is no danger of it being marred or touched by the grindingwheel, since the work is. effectively urged, by its weight, away from the grinding wheel and against the regulating wheel.

Any thrust on the work, caused by the on the work A` all as viewed in Figure 1, is

movement of the operative surface of the regulating wheel 7 in a direction toward the left,'as viewed in Figure 1, is taken up by the left-hand work-holding member 109; this particular work-holding member 109 thus insures that the work A has its axis properly held with respect to the axis of the regulating wheel so that the feeding action of the wheel 7, while the work A is out of contact with the grinding wheel 3, may be dependably carried on.

While the grinding wheel performs the grinding operation, there takes place a coaction of one of the work-holding or supporting members 109 with the regulating wheel; if the wheels are rotating in counter-clockwise direction, the'thrust of the grinding Wheel 3 taken up, by the right-hand member 109.

This member, however, will be seen to have,

as above noted, a surface, with which the workA contacts, which makes -an obtuse angle with a plane tangent to the grinding wheel 3 at the line of contact of the grinding wheel 3 with the work A. This inclined surface of the right-hand work-holding member 109 is the surface by which the thrust of the grinding wheel 3 on the work A is taken up and has such an inclination that a component of the grinding Wheel thrust is exerted in a direction to dependably urge the work toward or against the regulating wheel 7 and thus further insure effective contact between the surface of the regulating wheel and the work so that the former dependably controls the rotation and feed of t e latter. Under certain conditions, also, this inclined surface of that work-holding member which takes up the thrust of the grinding wheel von the work is of great aid in bringing about speedily a true rounding-up of the work operated upon. I

A water' pipe 102 (see Figures 3 and 1) is connected to the cross-piece 120 (see also vFigure the latter being provided with suitable passages 123 for guiding water to the point of contact between the grinding wheel and the work as the grinding wheel rot tates in counter-clockwise direction, as viewed .in F igurel. A plate 124 (see Figure 7) 1s ositioned to catch and guide away water that 1s thrown off of the grinding wheel .3, the latter, in Figure 7 rotating in clockwise` d1- rection. the view of Figure 7 being from the rear ofthe apparatus as the latter is seen in y Figure 1.

Because of the angular relation of the lower wheel 7 to the axis of the work when the wheel 7 is positioned to cause axial feeding movement of'the work the vsurface of the regulating wheel 7,which supports the work and which .for accuracy ofresults, should support the work perfectly throughout its length, is necessarily a curve and this curve is substantially hyperbolic. The regulating wheel 7 is trued to give it the desired curved surface so that it will present a straight line of contact to the work when it is adjusted to feed the work axially.

Considering now the apparatus for truing the wheels, reference may now be had to Figures 1, 3 and 7. The underside of. the carriage-113 is provided with spaced lu'gs 130 (see Figure 2) and these lugs support a shaft or rod 131 to the outer ends of which aresecured the brackets 132 and 133 A(see Figures 2 and 3).

Brackets

132 and 133 extend generally in a vertical plane and are preferably sha ed, in side elevation, as is better shown igures l and 7, from which it will be seen that the brackets are provided with arcuate slotsl34, the center of curvature of which is coincident with the axis of the shaft or rod 131. l

Screws 135 are threaded 4into the sides of the carriage 113 and pass through the arcuate slots 134 so that the arms or

brackets

132 and 133 may be locked in whatever position they may be swung within the ran e per-y mitted by the arcuate slots. During t e normal operation of the apparatus, the brackets which, being attached to the rod 131, swin as a unit with the latter, are moved and hel in their uppermost position, as is better shown in Figure 1.

The ends of the arms or

brackets

132 and 133 remote from the rod 131 are provided wlth suitable openings; thus, a hole or opening 139 in the outer end ofthebracket 132 is adapted to receive 'a bushing 138- while a similar hole or openin in the bracket or arm 133 receives the re uced end 143 of a sleeve 142, the latter being better shown in Figures 2 and 14. Set screws 144 (Figure 3) serve toI lock the bushing 138 and the sleeve 142 to their respective brackets. The central bores of the bushing 138 and of the sleeve` 142 are alined and are adapted to slidably guide a round rod 140 (see Figure 3). The

rod 140 carries a suitable cuttmg tool, such as a diamond 146, adapted, when "drawn across the face of either of the two wheels, to turn the latter down, as the rod 140 is moved longitudinally with respect to itself, a -knob 147 being provided to permit ease of manual sliding movement of the rod 140.

The sleeve'142, better shownA in Figure 14 on an enlarged scale, is provided with a straight slot'148 (see Figure 3)' extending through its wall and substantially diametrically opposite this, slot 148 there is formed in the sleeve a helical'slot 150. (Figure 14). A screw 145 threaded into the rod 140 is adapted to coact with either of these two slots.

When it is 'desired to dress or true the grinding wheel 3, the

brackets

132 and 133 are swung downwardlyfrom the position 145 is assembled as above-described, the diamond 146 will project upwardly from the rod 140, all as shown in Figure 3. a The brackets 1.32 and 133 are then locked in position by means of the locking screws 135, it being noted that the rod 140 is thus positioned and held in parallelism with the axis of the grinding Wheel The carr age 86 (see Figures 1 and 7) is then elevated by manipulating the hand Wheel 93 so as to raise the rod 140, with the diamond 146 thereon, to such a height that the rod 140 may be manually moved lengthwise of itself and the diamond 146 drawn Nacross the face of the grinding Wheel 3 to turn the latter down and dress it to its proper shape. During this sliding movement of the rod 140 the screw 145 (see Figure 3) is guided by the straight slot 148 in the sleeve 142 so that the cutting point of the diamond `146 3o moves along a straight line. During this op'- eration the grinding wheel 3 is, of course. rotated at a grinding speed.

If'the regulating-wheel 7 is set so that it exerts no feeding component upon the work A, and it is desired to true the wheel 7 to suit this condition, the set screw 144 (Figure 3) is loosened up and the sleeve 142 rotated through 180o and again locked in position, the diamond 146 being nowposi- 40 tioned on the underside of the rod 140 and in position to operate upon the wheel 7. The 'carriage 146 is then lowered by manipulating the hand wheel 93 (Figure 1) so as'to bring the diamond 146 to a suitable position for engaging and cutting the wheel 7 to the desired depth. The wheel 7 is driven wat high speed during this truing operation,

,the speed-change mechanism shown in Figure 8 and hereinabove described in detail 5o being adjusted orset to give the high trubeing operated upon, the sleeve 142, instead of being rotated through 180o, as above described, is left in the position shown in Figure 3; the wheel 7 is left in the position for no feeding action and the screw 145 re` moved from the rod 140. The rod 140 is then rotated through 180 from the posie5 tion shown in Figure 3, so that the diamond 150 causes a relatively slight swinging ofthe rod 140 about its axis in order thereby to vary or change the depth of cut being i taken by the diamond 146. The helical slot 150 is given a pitch proportional to the an- ,gle of feed which it is-de'siredto give the wheel 7 with respect to the axis of the work and through which angle the table 12 and the wheel 7 are to be swung in order to achieve a vcorresponding rate of feed. The wheel 7 is thus given the desired curvature so that, when it is subsequently swung through the desired feed angle, it will present to the work a straightline of contact therewith.

During these truing operations the rod 140 may be moved back and forth longitudinally as often as is desired to give the wheels the' desired smoothness of exposed surface. Of course, after the truing of theregulating wheel 7 has been accomplished, the speedchange mechanism is adjusted to a position such that the wheel 7 will be driven at the requisite low speed to effect control of rotation and control of feed of the work.

In order to facilitate adjusting of .the wheels to receive therebetween a predetermined diameter of'work, a graduated rod 153 (see Figures 1, 3 and 7) is" carried by one of the horizontally extending guide members 95, being preferably mounted in a boss 154 and being vertically adjustable. A set screw 155 serves to lock the graduated rod 153 in any desired position.l

The rod 153 extends downwardly through the guide member 95 and at its lower end is provided with a iinger156 extending transversely thereof and which may be swung inwardly to engage the face of the grinding wheel 3. The graduations carried by the rod 153 may then be read and, assuming that the' apparatus is to operateupon work of half inch diameter, the finger 156 and rod 153 may be moved downwardly half an' inch, gauged by the graduations, and locked in position. The regulating wheel 7 may then be raised by the mechanism hereinabove described in connection with Figures 8, 9 and 10 so as to bring the surface of the regulating Wheel 7 into contact with the nger 156. The latter' with its carrying rod 4153 may then be moved out of the way, test pieces may be put through the apparatus and final adjustments to achieve the intended diameter made by the mechanisms hereinabove described in detail.

Preferably the guide blades or work-hold.- ing members 109 are positioned so that their work-contacting facesl will hold' the work with the axis of the'latter arallel to the axisv of the grinding 'wheel W ere the latter is operative by its peripheral or rimface.

lIt will thus be seen that there has been rprovided in this invention a Grinding apparatusI in whichtheseveral o jects and advantages hereinbefore noted, as well as many others, are successfully achieve-d. It will be seen that the app-aratus is of thoroughly dependable construction and action and capable of'high degree of accuracy and efficiency of 'grinding and that it iswell adapted to meet the varying conditions of hard practlcal use.

As many possible embodiments may be made of the above invention and as many changes might bemade in'theembodiment 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. A centerless grinding machine comprising a horizontal arbor, a grinding wheel thereon, a ltable substantially below said grinding wheel and rotatable about a substantially vertical axis which'passes substantially through the center of the grinding wheel, an arbor mounted on the table and adapted to swing in a horizontal plane when said table is swung about said vertical axis, a work-supporting and regulating wheel on the lower arbor, means to rotate the regulating wheel slowly an-d the grinding wheel rapidly to respectively rotate and grind the work, and means to hold work between and in contact with the wheels.

2. In a grinding machine, a grinding wheel; a table below the grinding wheel and pivoted to swingabout a substantially verti- -cal axis; a spindle mounted on the table and adapted to swing in a substantially horizontal plane' upon said table being swung about its pivot; a work-rotating and supporting wheel on said spindle; and means to guide work between the wheels comprising a guide frame, carriages mounted on the guide frame, guide plates mounted in the carriages, and means to adjust the carri-ages independently of each other. i

3. In a' grinding machine, a grinding wheel; a table below the grinding wheel andpivoted to swing about a substantially vertical axis; an arbor mounted on the table and adapted to swing in a substantially horizontal .plane upon said table being swung about its pivot; a work-rotating and supporting wheel on said arbor; and means to guide work between the wheels comprising a guide frame,

means to raise and lower the guide frame,

guide plates to engage the work, and independently operable screws to position the guide plates.

4. In au centerless grinding` machine, a`

grinding wheel; a table underneath said grinding wheel and pivoted to swing l'about substantially vertical'axis; a'spindle rotatably mounted on the table and 'adapted to swing in a substantially lhorizontal plane upon said table being swung aboutv4 saidaxis;

a work-regulating and supporting wheel onf said spindle; means to' rotate the regulating wheel slowly and the grinding-wheel rapidly to respectively rotate and grind the work; means to guide work between the wheels;

means to raise and lower the work-guiding means; and means to raise and lower said table ripheral supportingy wheel mounted on said spindle and having a greater width than said f grinding wheel to support the work after it leaves the upper wheel, means for rotating the said wheels at respective'speeds and with their adjacent operative surfaces traveling in such directions as to elect simultaneousgrinding and rotation of the work, and a pair of spaced members extending lengthwise between said wheels for receiving therebetween work of contact with said wheels.

6. In a grinding machine, a horizontal arbor, a peripheral grinding wheel thereon, a table below the grinding wheel and pivoted to swing about a substantially vert-ical axis, bearings on the table and a substantially horizontal spindle in said bearings, a peripheral work-supporting wheel of greater width than the grinding wheel and mounted on said spindle, a pair of spaced Aplates to hold round work between the wheels, and means to rotate t-he arbors in the same direction, the surface speed of the peripheral face of the supporting wheel being so low that said supporting wheel controls the rotation of the work.

7. In a grinding machine, a frame, an arbor` rotatably mounted therein, a grinding wheel on the arbor, an arbor mounted below said r-` grinding wheel, a supporting wheel on the lower arbor having a work-engaging face of greater width than that of the grinding wheel, a pair of spaced adjustable guide plates between the wheels adapted to engage cylindrical work supported by the lower wheel, and means to rotate the supporting wheel slowly and the upper wheel rapidly to respectively rotate. the work positively and grind the same. j

8. In a grinding machine, a frame, a horizontal arbor rotatably mounted therein, a grinding wheel on the arbor, a frame rotatable on a vertical axis below and in the verticalplane of the upper arbor, a horizontal arbor mounted in the rotatable frame, a supporting wheel on the lower arbor of greater' length than the upper wheel, a pair of adjustable guide'plates between the wheels adapted able table,

to engage cylindrical work supported by the lower wheel, the opposed workcontacting edge faces of the plates making an angle with each other and being tangent to the cylindrical work. y

9. In a grinding machine, a pair of arbore, one directly above the other, a wheel on each arbor, the upper wheel on the upper arbor being a grindin wheel, a pair of spaced parallel work-holdlng members to guide cylindrical work between the two'wheels and parallel to the upper arbor, means to rotate the upper wheel rapidly tol grind the work and the other slowly to control the rotation of the work, and means to move said members transversely to the vertical plane of the upper ar bor, the opposed edges of the work-holding members being tangentto the work.

. 10. In a grinding machine, a frame, a horizontal arbor rotatably mounted therein, a

grinding wheel on the arbor, a-table rotatable on a vertical axis below and in a plane passing substantially vertically through the upper arbor,a horizontal arbor mounted in the rotata wheel made of abrasive material on the lower arbor of greater width than the upper wheel, a high and low speed changing device also mounted on the lower arbor to drive the same for the purpose herein set forth, and a pair of spaced guide plates bebearings below tween the two wheels adapted to hold round work between the wheels.

11. In a grinding machine, a horizontal arbor, asperipheral grindin wheel thereon,'a table below the grinding w eel and pivoted to turn about a vertical axis, bearin s mounted on the table and a horizontal ar or in said the grinding wheel, a peripheral abrasive wheel of greater width than the rinding wheel and mounted on the lower aror, a pair of spaced members to guide cylindrical work between the wheels, and means the grindingw to rotate the arbors in the same direction and at substantially the same speed for' t-ruing or at such different speeds that only the upper wheel grinds and the lower wheel controls the rotation of the work.

12. In a inding machine, a horizontal arbor, a grin in wheel thereon, a table below a vertical axis, below the first-mentioned arbor and adapted to swing in a substantially horizontal plane upon turning of the table, a work-supporting v and regulating wheel on the lowerl arbor, ad-

justable means to guide round work between and means `to-raise and lower said 13. In a grinding machine, a horizontal' arbor, a grinding wheel thereon, a table below the grinding'wheel and pivoted to turn about afvertical axis, anarbor mounted on the table below the first-mentioned arbori and adapted to swing in a substantially eel and pivoted to turn about` an arbor mounted on the tablel horizontal Aplane upon turning of the table, a work-supporting and regulating wheel on the upper wheel, and spaced work-holding members mounted between ythe wheels to guide the work in va straight line past the upper wheel and -also when the work is out of contact with the grinding wheel.

14. In a grinding machine, a horizontal arbor, a grinding wheel thereon, a rotatable table with its center in the vertical plane of the arbor, bearings mounted on the table and a horizontal arbor in said bearings, a wheel of abrasive materiall of smaller diameter but of greater=width than the first, means also mounted on the lower arbor for starting and stopping the lower wheel, and guides mounted parallel to the upper wheelb vand between the two wheels adapted to be Athe lower arbor and having a wider face than line or' to one side of the^vertical plane of I the ,upper arbor. I

15. A centerless grinding machine comprising a base. a peripheral grinding wheel mounted to rotate about a horizontal axis, a peripheral work-regulating wheel mounted to rotate about a horizontal axis and located -below the grinding wheel, means to rotate the grinding wheel rapidly and the regulating wheel slowly to respectively grind and rotatethe work, and means to hold work .between and in contact with the peripheries of the wheels in such a location that a line connecting the work center and a wheel center makes an angle with a line connecting the wheel centers so that the work will be ground at one side of the throat betweenthe wheels.

16. A centerless grindin machine comprising a base, two perip erally opposed abrasive wheels mounted thereon to rotate about horizontal axes, one above the other,

s aced work-holding members mounted on t e base and arranged to contact with c lindrical- V'work along linesparallel with -t e axis of one oflsaid wheels, and means .to

adjust said members vertically and horizontally vto grind all sizes of work, said parts bein so constructed and arranged that said mem rs may contact with'the work in' a plane perpendicular to the plane connecting the wheel axes and so that the work may be ground on a line at one side of a plane connecting the wheel axes.

17. A centerless grinding machine comprising a base," a grindin wheel mounted thereon for rotation, a wor fsupporting and regulating wheel opposed to the grinding wheel, means to rotate the grinding wheel at a rapid -rate and the regulating wheel at a work-regulating rate, two adjustable spaced work-holding members mounted to hold round work between andy in contact with the operative surfaces i of the wheels, means to move the said members toward and from each other, and means to move said members as a unit toward and from one of the wheels and substantially at right angles tothe .first-mentioned movement.

18. A centerless grinding machine com-.

prising a base, a grinding wheel mounted thereon for rotation, a work-regulatingwheel below the grinding wheel, means to rotate the rinding wheel at a rapid rate and the regu ating wheel slowly, two adjustable spaced work-holding members mounted to hold round work between and in contact with the opposed operative surfaces of the wheels,

a vertically movable support for said meinbers, a manually operable screw to move the support, and vseparately operable screwthreaded means to move" said members horizontally for any position of the support sol as to adjust the members finely.` relative to work of various sizes.

'19. A centerless grinding machine -comprising abase, a grinding wheel and a worksupporting and regulating wheel mounted thereon to rotate about horizontal axes in peripheral opposition, adjustable means supporting the regulatingwheel which permits it to be skewed relative to the grinding wheel so as to feed the work axially, means to hold work between and in contact with the wheel peripheries, means to rotate the grinding wheel rapidly and a multi-speed clutch mechanism including a manually operable control device located 0n the machine which is operable for any position of the regulating wheel to rotate it rapidly for truing lor at a slow speed `for workv regulation. i 20. A centerless .grinding machine comprising a grinding wheeljand a regulating vwheel mounted to rotate about horizontal axes, a support for the regulating wheel mov"- able towardfand from the grinding wheel to accommodate dliere'nt'slzes of work, and rotatablel about a line j passing lthrough the wheel centers so that the regulating wheel may be skewed relative to the grinding wheel. so as to cause axial feeding .movement of the work, means'to hold work in peripheral vcontact with the two wheels on the machine, vmeans to rotate thejgrinding wheel rapidly,

and. separate clutch-controlled power connections to rotate the regulatin wheel slowly j during. its feeding action on t 1e work while the grinding-operation is performed.- by thev grinding wheel or rapidly for truing the regulating wheel. l

21. A centerless grinding machine comprising a rapidly rotatable' grinding wheel, a slowly rotatable regulating wheel below the grinding wheel', said wheels being relatively movable towards and from each other, a work holding member therebetween, precision mechanism to adjust the work holding member vertically, and precision mechanism to adjust it horizontally relative to the wheels, said member having its operative face lying at an obtuse angle to a tangential plane passing through the line of contact of the grinding wheel and work whereby the thrust/ofl the grinding wheel and gravity cooperate to cause the work to maintain con.- tactwith the regulating wheel.

22. A centerless grinding machine comprising a rapidly'rotatable grinding wheel, v

a slowly rotatable regulating wheel, two spaced work holdingmembers located between the7 wheels, means to move one of the wheels towards and from the other, means to move said members towards and from each other, and means to move the members towards and from one of the'wheels in a direction at right angles to the other direction ofl movement, that member which receives the grinding wheel thrust having a beveled face which lies at an obtuse angle to a tangential plane `passing through the linel of contact of the rinding wheel and Work, whereby the wor tends to maintain contact with the regulating wheel.

23. In grinding apparatus, in combination, a grinding Wheel adapted to be rotated at a relativel adapted to he "rotated at. a relatively low speed, said wheelsbeing adapted-to present adjacent operative surfaces traveling in opposite directions, means Afor holding work of high speed, ,a regulating Wheel round section in operative relation to. said n vwheels,- means mounting said regulating means, and means ilo speed, `said wheels being adapted to present A adjacent operative lsurfaces 'traveling in @opposite directions, means for holding work of round section in operative relation to said wheels, 4means` mounting said regulating wheel to permit the relation of .its axis and hence to permit the inclination of the path of travel of its operative surface tobe changed relative to the path of travel of work along said work-holding means, and speedchange mechanism for driving the regulating .wheel and supported to be movable lwith the regulating wheel andthroughout the range of change in position of the axis of said regulating wheel.

25. In grinding apparatus, in combination,

a grinding wheel adapted tovbe rotated at a relatively high speed a regulating wheel adapted to be rotated at a relatively low