US1639958A - Centerless grinding machine - Google Patents

Description

I 1,639,958 1927' c. H. NORTON I GENTERLESS GRINDING MACHINE 4 Sheets-Sheet 1 Filed June 28. 1922 I M ar Charles H. NorTon Mam v I FWQF IM.

" 1,639,958 Aug. 23, 1927. NORTON CENTERLES S GRINDING MACHINE Filed June 28, 19 22 4.Sheets-Sheet 2 91* 92 92 .wmenzm v Charles H. NorTon I 1,639,958 A 1927' c. H. NORTON CENTERLES S GRINDING MACHINE Filed June 28, 1922 4 Sheets-Sheet 5 W Charles H NorTon Aug. 23, 1927.

c. H. NORTON CENTERLESS GRINDING MACHINE 4 Sheets-Sheet 4 Filed June 28, 1922 Chqrles NorTon Patented Au 23, 1927 CHARLES H.-'NORTON, OF WORCESTER,

. SIGNMENTS, TO CINCINNATI GRINDEBS INCORPORATED,

A CORPORATION OF OHIO.

MASSACHUSETTS, ASSIGNOR, BY MESNE AS-' OF CINCINNATI, OHIO,

CENTERLESS GRINDING MACHINE.

Application filed June 28, 1922. Serial No. 571,456.

My inventionrelates to precision grinding machines and moreparticularly to a machine for grinding cylindrical pieces of work without the, use of supporting centers.

The ordinary requirements ly fine limits of measurements and rapid, repeated duplication of accurately .sized work. Owing-to the time and expense involved in mounting such small objects as rollers on centers, various types of centerless grinding machines have been devised but difficulties have been met in supporting the work'accuratel" .and maintaining it in correct' position as grinding proceeds, as well as in the problem of truing the wheel.

One-type of centerless grinding machine has comprised opposed abrasive wheels, one utilized to grind the work and theother to rotate it.- The work has been supported against these two wheels by .a third fiat part or a convex surface placed below the work and engaging it on substantially a line contact.

In the course of my experimentation, I have found it to be of advantage in a precision grinding machine of this type that the cylindrical work be so supported that it cannotvibrate or change its axial position while rotating except as required by diminution in size as grinding proceeds and that irregularities of surface outline be ground out first to produce a cylindrical article before the final finishing operation can be effected. To accomplish such an object, I employ a work supportin shoe whichpresents a con- 5 cave instead of a flat or convex? surface to i i the work, and. preferably make this surface 0 Y With [a rest ofthis type the I have also cylindrical and of a radius equal to-the required radius of the finished piece of work. work tends to seek the shape of its supporting. surface, hence the 'irregularities of outline are removedfirst and the grinding proceeds until the workjust fits the curve of the shoe.

found that in a machine of this t pe it is of work be supported by such asteady rest below' a line oining abrasive wheels, .and mounted as to permit into contact for' truing one another. T is preferably takes place on -a" line passing through their centers and the normal line of for grinding small cylindrical objects "include exceeding.

some advantage that the the centers of the two that the wheels be sothem to be brought contact of the work with the grinding wheel in order that the grinding wheel surface may be formed exactly parallel on its grinding line of contactwith that of the work. It is accordingly a further object of my invention to provide a construction which accomplishes such ends and which will permit the abrasive wheels to be kept in true shape with the minimum of eflort on the part of the operator.

As a further consideration, 1 propose to maintain the axes of the work and its regua lating wheel parallel and to utilize the grinding wheel for feeding the work longitudinally by relatively tilting the axes of the grinding wheel and the work, whereby the work regulating wheel controls only the rotation of the work and the grinding wheel serves both to abrade the work and to move it axially at a rate which depends upon the angle of inclination. Precision feeding mechanism is also provided for feeding the grinding wheel and workrelatively toward each other and meansare employed for moving the two abrasive wheels and the work toward and, from one another in order,to provide for grinding work pieces of different sizes and to take up the wear of the abrasive wheels. Further objects of m invention are therefore to accomplish suc results and to provide mechanisms so, arranged and coordinated in a unified construction that various sizes and shapes of work may be ground automatically at a 'rapid, rate which may be varied depending upon the degree of accuracy andfinish desired.-

With these and other objects of my invention, as will be readily apparent in the following disclosure, my invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of my invention in-which like parts are indicated by like reference numerals: v Figure 1 is a right-end elevation 'of' my centerless grmding machine,

having parts broken away. and omitted to show the construction more clearly;

Fig. 2 is similarly a front elevationshowing particularly the work rotating wheel, its

adjustable supports and driving mechanism;

Fig. 3 is a left-end elevat1onal view;

Fig. 4 is an enlarged front View of the tiltable work driving wheel and adjusting mechanism, showing the wheels and Work in their correct positions for grinding;

Fig. 5 is a right-end elevation of the slide carrying the tilted Work driving wheel, showing the relative locations of the grinding wheel, work support, work and work rotating wheel;

Fig. 6 is a perspective detailed view of the steady-rest support for the work;

Fig. 7 is a sectional view taken approximately on the line 77 of Fig. 2, showing the manner of supporting the work rotating wheel slide, but with the strut removed and work rotating wheel in truing position;

Fig. 8 is a sectional view taken on the line 8-8 of Fig. 2, showing the universal gear casing; and v Fig. 9 is a sectional View taken on the line 99 of Fig. 8, showing the mounting of the gear casing 90.

In accordance with one phase of my invention I provide a centerless cylindrical grinding machine of the opposed wheel type in which the work is supported between the active faces of the wheels, and preferablythe peripheries thereof, by means of a steady-rest which serves as the sole support for the work and is constructed and arranged to support the work opposite the lines of contact with each wheel. This work support is preferably provided With a concave partial cylindrical surface, the

radius of which is substantially equal to that of the finished work, and it is so located and constructed that it will support the work in correct position for grinding and entirely without the aid of the opposed abrasive wheel's.

Another phase of my invention comprises utilizing the grinding Wheel notv only to abrade the work but to move it longitudinally, and to this end I maintain the work axially parallel with the Work regulating wheel and so support the grinding wheel and the Work that their axes are held at'a suitable angle, whereby one component of force produced by the rotating grinding wheel serves to move the work axially. If desired the machine may be so constructed that this angle of inclination may be varied,

. but this refinement in construction as well as various adjustment features hereinafter described may be omitted from the simpler types of machines designed for specific operations.

In order that the wheels may be trued, I provide means whereby they may be brought into contact, and preferably at the same position as the normal line of contact between the grinding wheel and the Work, the machine being so constructed that one of the wheels may be traversed across the face of the; other. Further details of a complete machine embodying my invention may comprise slides or other constructions which permit adjustment between the two wheels and the work supportto accommodate different sizes of work and to provide for moving the work and grinding wheel relatively to feed the wheel into the work and to adjust for grinding wheel wear.

In the specific embodiment of my invention, illustrated in the drawings, I have shown a centerless grinding machine having a two-part base, the part 1, upon which the wheel slide 11 carrying a grinding wheel 12 is slidably mounted, being preferably of standard construction as illustrated, details of which will be found in my prior patents and which form no part of the present invention. Upon the front base 2 are mounted various slides forming a carriage 13 whichadjustably supports the work-rotatiug abrasive wheel 14 in peripheral opposition to the grinding wheel 12. The wheel 14: is rotated slowly and controls the rotation of the work. Since the axes of the work and the Work rotating wheel should be parallel, I mount the steady-rest support 1.5 upon the carriage 13, the construction of the various parts of which will be later described, so that the work will be movable and tiltable with the work rot-ating wheel.

The steady-rest comprises essentially a work supporting part of the required shape and material which, as illustrated in Fig. 6, may be a shoe 16 removably mounted by means of a tongue and groove construction. on the support 15. For the reasons outlined above, this-shoe has a artial cylindrical surface of revolution 1? of a radius equal to that of the finished work, this surface in the form illustrated being bounded by noses 18 and 19 formed by intersection of the curved surface by the side surfaces of the shoe. These noses may be rounded and the side portions of the cylindrical work supporting surface may be flared out so as to provide wide surfaces of contact for the work before it has been reduced to the required radius, or they may be otherwise suitably constructed. It however is to be noted that in the ordinary use of this machine, the work may be and preferably is ground only a few thousandths of an inch at a pass, hence the rest is preferably made with a curvature equal tothat of the finished work so that the work may be held axially alined and all 'vibration is prevented. The steady-rest shoe is so located that the work axis is below a line joining the centers of the wheels. This arrangement is such that the centers of the wheels and the work are not in a diametrical plane of the work, and the angular relation of the lines ll U of contact of the work with the two wheels wheel tends to lift the work from the support, when rotating, but the work cannot shift from. its grinding position if the wheels are located in the relative positions as shown. It will be seen also that the same arrangement of parts will hold good for any other positions of. the wheels relative to the work support, since the chief function of the latter is to hold the work correctly located under the thrust of the p grinding wheel.

The construction of the grinding wheel mount may be of any suitable type, and is illustrated substantially as shown in my rior Patent No. 1,261,156, dated April 2, 1918. The wheel 12 is mounted on a suitable spindlev driven by belt 25 from the main drive shaft 26 in the base of the machine. In order to feed the grinding wheel toward and from the work as required during'the grindingoperation, I provide a suitable feed mechanism which may be of standard construction, comprising as illustrated a crank arm 30 mounted to rotate the shaft 31, the inner a pinion 32, adapted to mesh with the gear 33. This gear is mounted on the forward end of a feed screw 34. The wheel slide, which is slidably mounted on the usual V and fiatways, is provided with a half nut 35 engaging the feed screw 34. Any movement of the crank arm 30 will rotate the screw 34 in one or the other direction and feedthe grinding wheel toward .or from the work as desired. In order to feed the wheel with precision, I may employ a suitable micrometer hand feed mechanism 36 such as described in .detail in my prior Patent No.

762,838 dated. June 14, 1904. It is to be noted that in the ordinary grinding operation in which but little stock is removed from the work, after the grinding wheel has once been positioned for a certain size of workthe feed mechanism is necessary only to adjust the position of the wheel as it wears away.

. .The steady-rest shoe, as shown in Fig. 6, is made of considerable length relative to the size of the work, so that each piece may be moved axially during grinding to the machine to be fed continuously.

per device or chute of (not illustrated) may be provided to feed I oove 17 In the form illustrated, I utilize he principle that if the work is tilted relative to the grinding Wheel, it will be autom tically movedaxially as it rotates.

support may be built end of which is provided with suitable mechanism,

movement of the screw, as will be suitable construction.

this work regulating wheel and work rigidly fixed at a desired angle, but where it is desired to vary the rate of axial travel, the construction shown in the drawings may be employed. To this end, I provide a slide. 41'ca-rrying the work rest and work regulating wheel with curved V and fiat ways 42 and 43 respectively and mount them on corresponding ways onv the machine base 2. In order to adjust the position of this arcuate slide 41 to angularly locate the work rotating wheel, I may provide a suitable hand operated construction, such-as a screw and hand wheel, but in the drawings I have merely shown for the sake of simplicity of illustration a air of screws 44 which are screw threaded into the base 2 and passed through the elontion,

gated slots 45 in the slide 41, so that the n work rotating wheel 14 may be tilted axially to the desired angle and then the screws 44 tightened to hold the slide in adjusted posi tion. The axis of curvature of the ways on the base 2 coincides with the center line of the two wheels when the work rotating wheel is in the 'truing position or with the line between the centers of the work and the grinding wheel during grinding.

n the form illustrated, a second slide is mounted on the arcuate slide, which permits adjustment of the work and wheel 14 towards the grinding wheel. This construction comprises a slide 46 carrying a dovetailed slideway 47 on its under side which In a simplified construe- Hit] The slide 46in the present embodiment, is

provided with a dove-tailed slideway 51 upon which is adjustably mounted the slide 52, adapted to carry the work supporting steady-rest 15 and the support for'the work rotating wheel- 14. This slide 52 permit-s the work rotating wheel 14 to be adjusted laterally relative to the grinding wheel. This adjustment may also be accomplished by such as the screw 53 engaging internal threads 54 formed in the slide and actuated by hand wheelv 55, the screw and support being provided with engaging collar and flange to prevent axial 7 clearly understood. These slides foradjusting the position of the work and wheel 14 may of course be arraiiged and constructed in other we s within the scope of the principles underlying my invention, the above description bemg illustrative only.

- The steady-rest support 15 is rigidly mounted upon the rear of the slide 52, but in order that it may be removed to permit on an overhanging projection 61 of the slide 52. It is securely fastened in place by means of a bolt 62, so that the shoe 16 is maintained rigidly in position on a massive sup port which cannot vibrate or shift its position. I

The work rotating wheel 14 is also carried on the slide 52 with its axis mounted parallel with that of the work. In order to accommodate difterentsizes of work it is necessary that the -wheel and the Work be mounted for movement relative to each other. Also, since the work and its rotating wheel, in the operation of this machine, are tilted at some angle relative to'the path of travel of the operative surface of the grinding wheel to give the necessary feeding action by the grinding wheel, the grinding wheel should have a correctly concaved face so as to contact fully with the *work as the latter passes across the face of the wheel. I accomplish this by truing one wheel by the other with their line of contact exactly located where the work is normally ground. To this end, I mount wheel 14 pivotally so that it may be swung down'to a position where its axis is on a line with the normal center of the work and the center of the grinding wheel. Then, by traversing the slide 52 the work rotating wheel will pass across the face of the grinding wheel, the two wheels will be trued simultaneously, the wheel 14 in a cylindrical shape and the grinding Wheel 12 of theproper curvature to present a line contact across its entire face with the work during'grinding.

In the construction illustrated, the wheel 14 is rotatably mounted in suitable bearings 64 on the slide 65. This slide is mounted to move in a dovetailed slideway 66 on the member 67, which is mounted-to swing about the trunnion 68 supported from the slide member 52 bythe bearing brackets 69. As shown in Fig. 7, the bearing brackets 69 and trunnion 68 are hollow and concentric with the work, so that the latter when ground may be fed through them into a'. suitable receptacle. The slide 65 is adjusted by means of hand wheel 70, which operates the usual screw 71 fitted in threaded socket 72 in the member 67, the screw being fastened to slide by an end cap plate 73 secured between a collar on the screw and the hand wheel 7 0, as will be understood by reference to Fig. 7. By this construction I may adjust'the slide 65 upon its slideway and move the work rotating ,wheel 14 toward or from the work so as to produce the desired driving effect.

In order to satisfy the requirements set forth above as to the relative positions of the work rotating and grinding wheels, the work and the noses of the steady-rest shoe, I preferably locate the work rotating wheel 14 as high as possible. To this end I provide a suitable means such as a strut 75 which is removably positioned between the under surface of member 67 and the slide 52. To accommodate different sizes of work, struts of different length may be used, although other constructions may obviously be employed to adjust the position of the work rotating wheel. As illustrated in the drawings, this strut may be employed to accommodate various sizes of work by loosening the bolts and sliding the lower bracket to the desired extent. When it is necessary to true the wheels the strut may be removed and the wheel 14 swung about the axis of its trunnion untilvthe member 67 rests on the slide 52. after which the wheel 14 may be fed forward by means of the screw feed hand Wheel 70. Thereafter the wheel 14 may be traversed across the face of wheel 12 by turning the hand wheel 55. The steady-rest 15 will have been previously removedin order to permit en agement of the wheels.

ince the Wheel 14 must be. rotated in various axial positions, I provide a suitable universal or flexible drive which will permit the wheel to be tilted axially as well as be moved bodily in three directions as determined. by the slides 46, 51 and 57. In my preferred construction, I employ spiral gearingsmounted in universal casings and having a telescopic connection therebetween. As illustrated, a gear casing 90 is pivotally mounted on the spindle 91 which carries the wheel 14, so as to swing therea'bout. This spindle is provided with a spiral gear 92, meshing with a spiral gear 93 on the shaft 94. The'gear casing 95 ispivotally mounted in the casing 90 as shown in Fig. 8 so that it may swing about the axis'of the shaft 94, thus permitting a universal movement. On the other end of shaft 94 I provide the spiral gear 96, which meshes with the spiralgear 97, mountedon the vertical shaft 98. In order to permit the desired movement of the work rotating wheel 14, I telescope the shaft 98 within the hollow shaft 100 keyed thereto so that as'the position .of the work rotating wheel 14 is changed the shaft will lengthen or shorten as the case may be.

At the lower end of the shaft 100, I proyide another set of universally swinging gear I therein. It will be readil casings comprises a casing 101 supporting the lower end of the shaft 100 whic has a spiral gear 102 keyed thereto and meshing with a gear 103 on the shaft 104, the casing containing these gears being mounted sothat it may swing about the shaft 104 as a pivot. On the same shaft 104 I provide a spiral gear 105 meshing with. the spiral gear 106 on the shaft 107 mounted in the machine base. The casing 108 mounted to swing about the shaft 107 carries the shaft 104 suspended seen from the disclosure that the above escribed driving mechanism will permit a universal motion of the work rotating wheel 14, so that any desired adjustment may be accomplished. The shaft 107 is provided with a spiral gear 110, 111 on the shaft 112. This shaft is also provided with a spiral gear 113, which meshes with a-similar gear on the main drive shaft 26. The main drive, shaft 26 and the shafts 112 and 107 are mounted for rotation in suitable bearings within the base.

To eliminate any undue strain upon the telescopic shaft 98-100, I provide a telescopic guide rod 115 which is pivotally mounted on the projections 116 of the easing 90 and the projections 117 of the casing 108. As the work "rotating wheel 14 is moved to make the necessary adjustments, the guide rod will swing the casing 108 in accordance with thevposition of casing 90 and thus relieve the drive shaft 98-100 of the necessity to move the gear casing.

The grinding wheel 12 is driven at a fast rate of speed such as that used in a modern cylindrical grinding machine, but the work rotating abrasive. wheel is preferably driven at a slow speed compared with that of the The wheels are preferably direction, as so that the inding wheel. rotated in the same peripheral shown by the arrows in Fig. 1,

faces of the grinding wheel and the work rotating wheel adjacent to the work will be traveling in opposite directions; the rela tively slow speed of the work driving wheel will control the rotation of the work, thus permitting the piece of work by the grinding wheel.

In the operationv of myv machine which will be obvious from the above disclosure, I first set the arcuate slide at the proper angtl: to give the desired feed to the work to ground, then remove the strut 75 and swing the slide into the truing position and true the abrasive wheels." The member67 is then 'placed at the desired angle, depending upon diameter of the work. A steady-rest the shoe having its bearing face of a radius substantially equal to that of the finished size of the work'is located between the wheels,

' the workplaced therein and the work rotating wheel 14 then' advanced towardjthe, work like that shown. in Fig. 8. .This

which meshes with a corresponding gear the proper grinding action upon with respect to the grinding wheel 12 and the grinding Wheel is fedtoward the work the des1re'd amount. In order to adjust the grinding wheel to the proper position, a test piece of work is passed through the machine several times, the grinding wheel 12 being fed forward after each pass until the right diameter is obtained. Lhen the adjustment mechanism 36 is properly set to. locate the wheel, after which the machine is ready for use. The work is fed continuously into the right hand end of the steady-rest and passes through between the two "wheels which act upon the work as above described, the work rotating Wheel 14 controlling the rotation of the work and the grinding wheel 12 performing the grinding operation and effectmg also an axial movement or feed of the work along the work rest. From time to time, as the grinding wheel 12 wears away, 1t will be necessary to adjust the feeding mechanism by moving the micrometer adustment to permit the crank arm 30 to be rotated a short distance to take up the wear of the wheel.

As many possible embodiments may be made of the mechanical features of the above invention, all without departing from the scope of the invention, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative .and not in a limiting sense. 7

I claim:

1. A centerless grinding machine comprisinga rotatable grinding wheel, a work regulating wheel rotatably mounted opposite thereto, means to rotate the grinding wheel rapidly and the regulating wheel :slowly in ,order to respectively grind and rotate work positioned-therebetween, and-a work posi tioning member arranged and positioned to maintain a piece of work in operative contact with said wheels during the grinding operation, said member having an extensive concave .c lindrical work positioning surface of en stantially the same radius as that of the finished Work.

'2. A center-less grinding machine compris ing rotatable grindingand regulating wheels whose peripheries are arranged close together, means to rotate the grinding wheel rapidly and the regulating wheel slowly,

to respectively grind and rotate the work, and a member having a concave cylindrical surface of substantially the radius of the finished work arranged to position the work between and in operative relation to said wheels,;the center of the work'being out of line with the centers of the wheels.

3. A. grinding machine comprising a rono I tatable grinding wheel, a work regulating wheel peripherally opposed thereto, means to support the work regulating wheel w1th its axis in angular relation to that of the grinding wheel, means to rotate the grinding wheel at a rapid rate and theother wheel at a slower rate to respectively grind and rotate the work, and a steady-rest to support the work between and in contact with the wheels below a line connecting their centers which has a concave cylindrical surface of substantially the radius of the finished work which is so located as to hold the work axia-lly parallel with the axis of the work regulating wheel.

. t. A centerless grinding machine comprising a rotatably driven grinding wheel, an adjustably mounted, work regulating abrasive wheel, a movable work support between said wheels adapted to hold the work against the wheel faces during the grinding operation but making contact there at a point offset from a line connecting the axes of the two wheels, and means for moving the wheels into engagement at the normal position of contact of the work and grinding wheel.

5. A centerless grinding machine comprising o'pposed rotata-bly driven, grinding and regulating wheels, asteady-rest removably located therebetween to support the work in operative contact with said wheels, means to move said wheels relatively into truing contact and means 'for causing a relative traversing movement between the wheels while in'contact.

6. A centerless grinding machine com;

prising a rotatably driven grinding wheel, .an adjustably mounted, work regulating, abrasive wheel peripherally opposed thereto, a work support between the wheels to hold the work in operative contact with the peripheries of said wheels, means permitting removal of the work support from between the wheels, means for moving the work regulating wheel into engagementgwith the grinding wheel and means to traverse one of said wheels across the face of the other to true the surfaces thereof.

-7. A' centerless grinding machine comprising ,a base, a rotatable grinding wheel mouiited thereon. a work regulating abrasive wheel peripherally opposedthereto, a slide carrying the regulating wheel whichis movable parallel with the wheel axis, means to rotate said wheels for all positions thereof, a removable support to hold the work in contact with the peripheries of thewheels, means for moving the work regulating wheel into contact with the grinding wheel, and means for transversing the slide to true said wheels.

8. A grinding machine comprising a rotatable grinding wheel, a work regulating abrasive wheel peripherally opposed thereto, one of said wheels being axially tilted relative to the other, means to rotate said wheels, means to support the work in peripheral contact with said wheels, means to move the wheels into contact at the normal position of contact between the work and the grinding wheel and means to traverse one of the wheels parallel with its axis to true the wheels.

9. A grinding machine comprising a rotatably driven grinding wheel, an adjustably mounted, rotatively driven, work regulating, abrasive wheel, means to support the abrasive wheel with its axis tilted with re-' spect to the axis of the grinding wheel, a work rest positioned closely to the periphery of the grinding wheel and supporting the work parallel with the axis of the Work 1'0- tating wheel, and means for moving the work rotating wheel intocontact with and traversing it across the face of the grinding wheel to true the surfaces thereof.

10. A grinding machine comprising a rotatably driven grinding wheel, a movable support, a positively driven axially tilted, work regulating abrasive wheel mounted on said support in peripheral opposition to the grinding wheel, a steady rest on said support having a concave cylindrical work supporting surface adapted to hold the work axially parallel with said abrasive wheel, and means for moving saidv support and abrasive wheel and work thereon toward-or from the grinding wheel.

11. A-grinding machine comprising a rotatably driven grinding wheel, a positively driven, work regulating abrasive wheel, a tiltable support for the abrasive wheel mounted to tilt the abrasive wheel about an axis which cuts the line of contact of-grinding wheel and work, a steady-rest on said support having a concave, cylindrical, work supporting surface adapted to hold the work in contact with the wheels and axially parallel with said abrasive wheel, and means to feed the grinding wheel and work relatively towards each other.

12-. centerless grinding-machine comprising a base, a rotatablydriven grinding wheel mounted thereon, a work regulating wheel opposed to said grinding wheel, a member mounted on the base for arcuate movement about a line passing throu h the wheels and carrying said work regu ating, wheel, a slide mounted on said memberarranged for movement toward and from the grinding wheel and a work rest mounted on the slide between the active surfaces of the wheels.

13. A grinding machine comprising a rotatably-driven grinding wheel, a rotatably drlven, work regulating abrasive wheel peripherally opposed thereto, a tiltable support for said abrasive wheel and a steadyrestmounted on said support. to tilt there- -with, said-steady-rest having a concave 9 cylindrical surface located between the two wheels and adapted to support, the work in contact therewith.

14. A grinding machine comprising a rotatably driven grinding wheel, a driven, work regulating abrasive wheel in pe; ripheral opposition thereto, a slide arranged to support the abrasive wheel in tilted relation to the axis of the grinding wheel, a steady-rest on said slide having a concave cylindrical surface adapted to hold the work axially parallel with thetilted wheel and in contact with both wheels, and fine precision means to adjust the position of said slide.

15. Agrinding machine comprising a base,

.a rotatably driven-grinding wheel mounted thereon, a driven work regulating abrasive wheel peripherally opposed thereto, a slide mounted on said base which is movable in a plane tilted relative to the horizontal, a steady-rest on said slide having a surface for supporting the work in peripheral contact with the wheels, and a second slide mounted on the first slide and carrying said abrasive wheelfor movement toward and from the steady-rest.

from each other in order to accommodate different sizes of work.

17.- A grinding machine comprising a positively driven grinding wheel and a positively driven, work regulating abrasive wheel peripherally opposed to the grinding wheel, a support to hold said abrasive wheel in an adjustable position comprising a hollow trunnion and bearings axially aligned with the axis of the work and a work support adapted to hold the work in contact with the wheels, said hollow trunnion and work support forming a passage for the pieces of work.

Signed at Worcester, Massachusetts, this 22nd day of June, 1922.

CHARLES H. NORTON.

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