US2787094A

US2787094A - Cutter grinders

Info

Publication number: US2787094A
Application number: US470207A
Authority: US
Inventors: Warren F French
Original assignee: William H Field Co Inc
Current assignee: William H Field Co Inc
Priority date: 1954-11-22
Filing date: 1954-11-22
Publication date: 1957-04-02
Anticipated expiration: 1974-04-02

Description

i w. F. FRENCH April 2, 1957 CUTTER 4GRINDERS 4 Sheets-Sheet 1 April 2, 1957 w. F. FRENCH 2,787,094

CUTTER GRINDERS Filed. Nov. 22, 1954 4 Sheets-Sheet 2 (U MQ l 1 I L .,l

FIG. 2

WARREN F. FRENCH lNvENToR BY E ATTORNEY April 2, 1957 w. F. FRENCH CUTTER'GRINDERS 4 Sheets-Sheet 3 Filed Nov. 22, 1954 FIG. 6

WARREN F. FRENCH INVENTOR April 2, 1957 w. F. FRENCH CUTTER GRINDERS 4 Sheets-Sheet 4 Filed Nov. 22, .1954

Rororionol Axis Y-Yof Diamond Wheel Dreser Dn/O+ Am of wheel Head for Clearance Angle Sehinq WARREN F. FRENCH INVENTOR WY i ATTORNEY United States Patent O CUTTER GRINDERS Warren F. French, Brockton, Mass., assignor, by mesue assignments, to William H. Field Co., Inc., Boston, Mass., a corporation of Massachusetts Application November 22, 1954, Serial No. 470,267

Claims. (Cl. 51--123) This invention relates to grinding machines, and more particularly to improvements in cutter grinders. More especially it relates to an improved cutter grinder for sharpening helical bits, cutters with helical lutes, and like cutting tools, as Well as being adapted for use in sharpening the cutting edges of various cutters having straight ilutes or teeth. The invention contemplates novel and eiective positioning means for setting the height of the work supporting portion of a tooth rest accurately on center with the rotational axes of both the grinding Wheel and a cutting tool in a work support. The invention further contemplates novel wheel dressing means whereby the annular end grinding surface of a cup-shaped grinding wheel employed to grind a cutting tool will be dressed or reshaped to vary Iaccurate arcuate form or contour laterally of the wheel rim to provide a peripheral datum circle at the point of greatest convexity to which the work contact point of the cutter supporting tooth rest bears a substantially constant position regardless of the clearance angle being ground on the cutter.

ln the particular form of the embodiment of the invention herein illustrated, the cutter grinding machine is provided with a longitudinally reciprocable and laterally adjustable work supporting means and an angularly adjustable elevatable or altitudinally positionable grinding wheel head including a cup-shaped grinding wheel having an annular end grinding surface provided with a convex periphery laterally of its rim made by dressing or shaping the same on a radius crosswise of the rim so that its convex grinding face is of substantially semi-circular contour. The grinding wheel head includes an angulariy adjustable grinding wheel slide in 'a vertical plane and a vertically adjustable carriage on which the wheel slide is mounted. The grinding wheel slide is so arranged that its vertical angular adjustment is about a horizontal line or center lying forward of and parallel with the horizontal diameter of the operating grinding surface in a plane containing the rotational axis of the grinding wheel and also passing through the tip extremity oi the work supporting contact point of a tooth rest which is ilxedly mounted on the wheel head and movable bodily therewith during any altitudinai and angular adjustment of the wheel head. The wheel dressing means is mounted for 180 movement in a vertical plane passing through the rotational axis of the grinding Wheel and also is iixed to the wheel head. The wheel dressing means is arranged 'to pivot or swing about a horizontal line or axis parallel with the aforementioned pivot axis of the Wheel head and passing through the center of the radius of curvature of convex peripheral end of the grinding Wheel rim.

Two forms of height setting or gauging means are provided on the machine, one being a hinged arrangement adapted for use in setting on center with the axis of the cutter to be sharpened the contact portion of tooth rests of either the fixed type fast on the Wheel head or a blade mounted on a mandrel carrying the cutter to be operated on; and the other form being a pair of relatively movable plate members, one being adapted for use only with helical flute cutting tools and arranged for vertical movement with the wheel carriage and the other being stationary, and each bearing cross markings which are aligned when the wheel carriage is set at the correct height to place the contact point of the tooth rest on center with the axis of the cutting tool in the work supporting means.

The invention has for one of its objects to provide a cutter grinding machine wherein the setting of helical ilute or straight uted or toothed cutting tools is simplitied and a predetermined lip clearance can be obtained which is uniform throughout the longitudinal extent of a particular cutting edge of the tool and can be duplicated upon each of the flutes or teeth thereof.

Another object of the invention is to provide a cutter grinding machine of simple andcompact construction Vwhich can be used by a workman without previous experience, and without skilled labor, and by means of which helical or straight luted bits and cutters may be rapidly and accurately ground and sharpened.

Another object of the invention is to provide a tooth rest for helical cutting tools xedly supported on a grinding wheel head and adjustable only laterally thereof in relation to the annular end grinding surface of a grinding wheel.

A further object of the invention is to provide a tooth rest for helical cutting tools in which the contact point of the rest bears a substantially constant xed relation with a datum circle formed on the grinding face of the grinding wheel and also is intersected by a diametrical plane containing the wheel axis and the axis of the cutting tool to be ground.

A still further object of the invention .is the provision of accurate means of setting the height of the contact point of a tooth rest precisely on center with the axes of the wheel and the cutter to be ground :and without being affected by changes in clearance angles.

Another object of the invention is the provision of radius wheel dressing means to generate a convex grinding surface on the wheel in which the point of greatest convexity lies on a peripheral datum circle around the grinding wheel face and to which the contact point of the tooth rest is xedly positioned.

In the accompanying drawings:

Fig. l is a fragmentary perspective view, partly in section, of a cutter grinding machine according to the invention, and showing one of the height setting devices being used to set `the contact point of the tooth rest employed in sharpening a helical cutter accurately on center with the cutter axis;

Fig. 2 is a top plan view of the cutter grinder shown in Fig. l but showing the articulated height setting device being used in a gauging position;

Fig. 3 is an end elevational view, partly in section, of the cutter grinding machine shown in Figs. 1 and 2 looking at the right end of Fig. 2;

Fig. 4 is a fragmentary perspective View, partly in section, of the cutter grinding machine shown in Fig. 2 but showing a milling cutter supported on a mandrel in grinding position and with the articulated height setting device for the tooth rest carried by the mandrel being swung into a gauging position;

Fig. 5 is a fragmentary pictorial view of the forward end portion of the grinding wheel` slide showing more or less diagrammatically and in end elevation the cup-shaped grinding wheel partly in section, the tooth rest for helical cutters in operating position to the grinding wheel, and the axial disposition of the wheel dressing device to the grinding wheel;

Fig. 6 is a fragmentary top plan view of the cupshaped grinding Wheel `anti tooth rest as shown in Fig.

5 with the grinding wheel partly shown in section so as vto illustrate the rim contour and also the operating poavenues *s sition of the tooth rest to the convexed grinding surface; and

Fig. 7 is an enlarged fragmentary side elevational view showing the grinding operation in progress on a helical bit.

Referring to the drawings in detail, there is shown in Figs. l, 2 and 3 a cutter grinding machine embodying the present invention in which the reference numeral 1i) denotes, generally, a grinding wheel head assembly which comprises a grinding wheel slide 12 and a supporting carriage 13 therefor arranged for vertical movement along suitable dovetail slideways for altitudinal adjustment of the carriage on a bracket 14 upstanding from and iixedly mounted on a base member 15 for the machine. Vertical movement of the carriage 13 is by a manually-operated ball-crank machine handle 16 and a suitable feed screw 17. The grinding wheel slide 12 overhangs a laterally extending arm 1S of the carriage 13 and is supported for angular adjustment thereon in a vertical plane perpendicular to the plane of vertical altitudinal adjustment of the carriage by inter-engaging upright arcuatelyshaped lnachine slide members 19 and 2t) which are iixed to the outer end of the arm 18 and to the grinding wheel slide 12, respectively. The grinding wheel slide 12 is provided with overhung bearing portions 21 and 22 respectively, which extend forwardly and rearwardly of the slide and in which is journaled a spindle 23 having removably mounted on its forward end a grinding wheel 24 past which is reciprocated a horizontally reciprocable table Z5 carrying a work supporting head 26. A V- belt drive is employed for driving the grinding wheel spindle Z3 from an electric motor 27, the drive comprising a V-pulley 23 secured on the rear end of the spindle 23 and about which passes a V-belt 29 which is driven by a V-pulley 30 on the shaft of the electric motor 27. The arcuate slides 19 and 2l) are provided respectively with a graduated scale 31 and a pointer 32 to facilitate the setting of the grinding wheel slide 12- angularly a predetermined amount for the Wheel to grind the proper clearance angle on the cutter.

The grinding wheel 24 is of cylindrical cup-shaped form and, in the illustrated arrangement of the machine as shown in Figs. l, 2 and 3 of the drawings, is formed with an annular convexedly curved end grinding surface 33 which is operatively arranged in proper relation to the work contact point 34 of a tooth rest 3S to grind the peripheral edge of the particular iluted portion of a helical bit or cutter herein designated by the letter W (see Fig. 7), as will be hereinafter described.

The tooth rest 35 for helically iluted cutting tools is attached to the wheel head 12 in an oifset position alongside of the grinding wheel 24 and is adjustably mounted and clamped 'in a suitable channeled guideway 36 (see Fig. 4) formed in the side of an enlarged end portion 37 of the front bearing portion 21 for longitudinal adjustment only in the guideway 36 for setting of the contact point 34 of the tooth rest correctly to the end grinding surface 33 of the grinding wheel. It will be noted that the grinding wheel slide 12 is mounted for vertical angular adjustment on a horizontal line X--X lying in a plane at right angles to the rotational axis of the grinding wheel spindle 23 (see Figs. l and 5). For the purpose of so adjusting the grinding wheel slide 12, there is journaled in this slide a hand screw 38 having suitable pivotal connection (not shown) at its bottom end with the arm portion 18 of the carriage 13 whereby upon appropriate manual turning of the screw 38 the arcuate slide member Ztl will be moved in the arcuate guideway of the slide member 19 and together with the wheel slide 12 will be angularly adjusted in any desired position in a radial line which is normal to the axis X-X about which the grinding wheel slide 12 is adjustable. The slide 12 is secured in place in its adjusted Ior operating positionl 4 ber 20 and slidably passing through an arcuate slot 41 (see Fig. 3) in the arcuate slide member 19.

The table 25 is .slidably mounted for longitudinal reciprocation upon a transversely adjustable slide 44 by means of free-moving, anti-friction rollers 45 engaging a V-edged plate or track member 46 which extends longitudinally beneath the table 25 and is mounted in a crosswise relation upon the slide dll, as shown in Figs. 3 and 4. The table 25 is hand-propelled by the machine operator past the annular end grinding ,surface 33 of the grinding wheel 24 in a direction at right angles to the axis of the grinding wheel spindle 23 during grinding of a bit or other cutting tool and returned to its initial position at the right end of the machine by means of a suitable spring (not shown) operatively connected with the table 25 and the slide 44 and adjustably tensioned by a hand screw device 47. The transverse slide 44, in turn, is operatively arranged for longitudinal sliding movement back and forth on suitable dove-tail ways of a guide member 43 by means of a suitable feed screw indicated at 49 turned in a threaded portion 49 of the guide member 4S by an operating handle 5G. The work head 26 here shown is of a known construction and provided with an inflexible work-supporting collet 51 which may be rendered freely rotatable by release of a pin plunger 52, and this collet is arranged in a known manner for longitudinal movement in a large hub member 53 overhanging a disc-like base member 54 or' the work head. T he hub member 53 is pivoted in the upper part of an upright arm 55 integral with the base member 54 of the work head and is adapted for angular adiustment on this arm in a vertical plane by means of an operating lever 56 as well as being adjustable angularly in a horizontal plane by rotary movement of the work head base member S4 about a vertical axis here shown as the central mounting stud 57 which secures the work head 26 to the top of the table 25. An enlarged hand-operated clamping nut 58 having operative connection with the usual threaded shank end of the collet 51 operates to draw it longitudinally with respect to the hub member 53 to effect tight clamping of either a bit shank or a cutter .supporting arbor in the collet Sl.

To properly shape `the annular and convexedly curved end face 33 of the grinding wheel 2li so that it will be of the proper arcuate form with its crown opposite the contact point 34 of the .tooth rest 35 and lying on a peripheral datum circle D around the end face of 4the wheel, it is necessary that the dressing or reshaping operation be carried out on an arcuate line lying in a vertical plane which includes the rotational axis of tie grinding wheel 24 and which is generated about horizontal axis Y-Y about which the wheel dressing device revolves in forming the convexed end grinding surface 33 of the grinding wheel. .ln the present illustrative disclosure, the radius wheel truing or dressing means associated with the grinding wheel 24 and indicated at di) is a micrometer device comprising a diamond 61 mounted in the end of a spindle and lead screw 62 threaded in a barrel 63 which Iis fixed in a hub portion del of a vertical swinging arm 65. The arm 65 has 180 pivotal movement by pin 66 on a bracket 67 attached to a dovetail slide 655 which caps the top of the enlargement 3? of the grinding wheel slide 12 and is arranged to be adjusted and clamped by a suitable .stud in any adjusted position thereon. A beveled thirnble di? is rigidly fixed to the lead screw and spindle 62 and fits down over the barrel 63 but does not engage it. The beveled end of the thimble 69 is suitably graduated around its circumference, and one side of the barrel lalso is marked with suitable graduations in 1a longitudinal line `for accurate adjustment of the position of the diamond point. rthe swinging arm 55 has a handle 79 for moving the point of the diamond 61 back and forth crosswise of the rim of the annular end face 33 of the grinding wheel 2d as indicated in Fig. 5 in order to true and/ or dress the grinding surface thereof and give it the desired semi-circular arcuate contour.

Means are provided for setting the height of a tooth rest on center with the axis of the work to be ground and for positioning a particular cutting edge to be ground in a horizontal plane passing through the axis of the cutting tool held by the work support 26. In .the illustrated embodiment, two distinct and separate height setting devices designated generally by ythe numerals 70 and 71 are provided on the machine as .shown in Figs. l to 4 inclusive of the drawings to facilitate this positioning of the tooth rest and the lip of the cutter. The height setting device 70 is made up of -two plates 72 and 73 of which the former is attached to the side of the carriage 113 `and the latter fixed on the side of the bracket 14, both being mounted close to the vertical partingy line between the carriage and the bracket. Each plate is marked cross-wise with ya centering line as indicated at 74 which lines are brought into horizontal alignment one with the other as depicted in Fig. 1 and indicate that the -altitudinal adjustment of the grinding head is correctly positioned to place the contact point 34 of the tooth rest 35 and lthe cutting edge of the cutter lip correctly on center with the axis of the cutter being sharpened. The second height setting device 71 herein illustrated is an articulated gauge arrangement which is pivotally mounted on the top surface of a at plate-like projection 75 extending laterally outwardly from the side of the work support 26, as shown in Figs. l, 2, 3 and 4. The gauging device 71 comprises three pivotally connected horizontally disposed arm members 76, 77 and 78 of which the arm 76 is pivotally mounted at its inner end on the top surface of the projection 75, fthe arm 77 has swinging movement under the outer end portion of the arm 76, and the arm 78 constitutes the feeler finger of the gauge and is positioned on top of the arm 77 at its outer end. The horizontally disposed gauging surfaces of the device, viz., the top surface of the projectio-n 75, the bottom surface of the arm 76, the top surface of the arm 77, and the bottom `'surface of the feeler `arm 78 all are precision-ground or lapped absolutely flat surfaces throughout their entire extent. It should be noted that the flat top surface of the projection 75 exactly lies in a horizontal plane passing .through the longitudinal axis of the work-supporting collet 51 and, consequently, the rotational axis of the cutter to be Vground when held in the work support 26. The arms 76, 77 and 78 of the gauging device 71 are adjustable with respect to each other and the entire device 71 may be swung aside into an inactive position when not in use, as depicted in broken outline in Figs. l and 2. Y

In sharpening helical bits or helical flute cutters with the apparatus above-described, the grinding wheel slide 12 may be set rst to the proper clearance angle, such as for example, ten degrees from vertical according to the scale 31 and pointer 32. Then, the grinding wheel 24 is dressed by means `of the radius wheel dressing device 6d to provide la convex grinding surface 33 on the annu' lar end face of the grinding wheel. Prior to this dressing operation or at the completion thereof the proper size and hand of tooth rest 35 is mounted in position in the channel-shaped groove 36 of the portion 37 of the grinding wheel slide 12 yand the work contact point 34 of the tooth rest adjusted to place it close to the convex end grinding face 33 of .the wheel but without touching the wheel surface, i. e., approximately .010 of an inch, and also in juxtaposition with the4 datum circle D of the wheel. Then the height gauge 7l is swung around as indicated in Figs. l and 2 so that the flat bottom gauging surface of the feeler ar-m 78 of the height gauge 71 extends over and touches the tip of the contact point 34 of the tooth rest, the elevation of the grinding wheel 24 and the wheel head 10 being adjusted by appropriately raising or lowering movements of the carriage 1-3 on the bracket 14 by means 'of the ball-crank handle 16 and feed screw 17. When thus set, the height gauge is swung aside out of the way as depicted in Figs. l and 2. If, however, it is desired to use the height setting means in lieu of the |articulated arm device 71, then the contact point 34 of the tooth rest 35 is set on center in `a horizontal plane with the axis of the cutting tool by adjusting the altitudinal position of the wheel head 10 by the ball-crank handle 16 and feed screw 17 until both cross centering lines 74 on the side plates 72 and 73 are longitudinally aligned thereby indicating that the tip of the contact point 34 of the tooth rest 35 is set on center in a horizontal plane passing through the axis of the cutter or bit. Regardless of which gauging or setting means is employed, the tip of the contact point 34 of the tooth rest 35 will lie in a plane containing the grinding wheel axis and the line X-X about which the grinding wheel slide 12 is angularly adjusted.

During the grinding operation on cutting tools, such as helical bits and cutters having helical tintes, it is merely necessary to insert the shank of the cutting tool to be sharpened in the work-supporting collet 5l, after which the traverse slide 44 together with the table 25 and the work head 26 is fed inwardly by appropriate movement of the operating handle 50 until the lip of a particular flute of the cutting tool engages over and is supported by the contact point 34 of .the tooth rest 35. The cutting tool then is moved longitudinal-ly past the grinding Wheel 24 while in engagement with its rounded end grinding :face by manual reciprocation of the sliding table 25 While holding the tool revolved and pressed against the contact point 34 of the tooth rest by means of the collet clamping nut 5S. in this way, as the cutting tool is moved lengthwise the helical lead `of its cutting edge or lip will turn the cutting tool about its own axis in the work support 26, since it is now freely turnable therein due to previous releasing movement of the pin plunger 52, and thereby will bring successive portions of the helical flute being operated by the grinding wheel into the proper grinding plane while thus supported by the tooth rest anduntil the cutting tool stops turning when the end of the particular helical ute is reached. This procedure may be repeated several times for each ute land until all the lips of all of the cutting tool have been ground and sharpened. The helical bits or cutting tools to be ground can be any length, four inches being usually the maximum limit for router bits. The size, angle and hand of helix of the contact point 34 of the tooth rest 35 will, of course, depend upon the hand and angularity of the twist or lead of the helical cutting edge of the particular cutting tool to be ground and, in practice,

many possible combinations of helix and hand of cut are possible so that a number of appropriate hands of tooth rests are used to meet the various requirements of helical ute bits and cutters operated upon by the grinding machine.

In the event that a straight fluted cutting tool, such as a milling cutter C is to be sharpened, reference is made to Fig. 4 of the drawings in which a milling cutter C having the cutting edges of its straight teeth to be ground by the cup wheel 24 is mounted for free rotation upon a suitable shaft portion (not shown) of a mandrel herein designated generally by the reference numeral which is supported in the horizontally extending overhanging fashion hereshown by a shank portion (not shown) held fixed in the collet 51 of the work support 26. A spring 83 acting between the rear side of the cutter C and a clamping nut 84 exerts a restraining force against the cutter C to prevent it from turning too freely on the mandrel during indexing of the cutter teeth as well as serving to keep the cutter C square with the cylindrical face of its supporting shaft portion of the mandrel 80. A flexible tooth rest 85 consisting of a blade member made of at sheet spring stock is adjustably mounted in a laterally extending position on the outer end of a bar member 86, which in Aturn is slidably mounted in and adjustable radially of a hub portion 87 of the mandrel S0. The tooth rest blade 85 is longitudinally slotted as indicated at 88 to permit its height to be set relative to a particular tooth of the cutter C on the mandrel after which the tooth rest is clamped in place in its set position by means of a stud 90 and washer 91. The specific construction of this cutter grinding mandrel 80 with tooth rest 85 forms no part of the present invention since its structure forms the subject matter disclosed and claimed in my copending application, Serial No. 445,003 which was filed July 22, 1954 and has since led to Patent No. 2,725,690, granted December 6, 1955.

From the above description it will be apparent that I have provided a novel cutter grinder adapted to grind helical flute bits and like cutting tools as well as milling cutters having straight peripheral teeth in a simple and accurate manner, the grinder being of compact form adapted to be mounted upon a bench and to be operated by a comparatively unskilled workman or one without previous experience in cutter grinding. It will also be apparent that by reason of the novel mounting arrangement of the grinding wheel head the whole grinding wheel slide 12 including the grinding wheel 24 itself is angularly adjustable to grind desired clearance angles on the cutting tool and the angular movement of the grinding wheel slide is about a line or axis passing substantially through the contact point of a tooth rest which remains in fixed height relation and on center with the work axis when once set in this position by use of either of the height setting devices 7i) or 71 which constitute one feature of my invention. Thus by my improved mounting arrangement of the wheel head I have obviated the prior general procedure of separately making adjustments to bring the center of the wheel and the work as Well as the contact portion of the tooth rest all into the same plane and then raising or lowering the wheel head (or the table) the proper distance to give the desired clearance angle since with my machine the tooth rest contact point position is fixed by its mounting on the wheel slide 12 and maintained in a predetermined relation to the grinding surface 33 of the grinding wheel 34 where it remains unaffected by clearance angle adjustments by reason of the angular positioning of the grinding wheel slide 12.

While l have described a preferred form of my invention, it is to be understood that various modifications and changes in form and details of construction may be made therein within the range of engineering skill without departing from the spirit and scope of the invention as defined in the appended claims, and it is therefore my intention not to limit my invention in any manner Whatsoever except by the terms and scope of the appended claims.

What is claimed is:

l. In a machine for grinding helical cutting tools the combination of a grinding wheel head adjustable for altitudinal movement in a vertical plane and also angularly in a lateral direction in a vertical plane perpendicular to said vertical plane of altitudinal adjustment of the wheel head, a grinding wheel spindle rotatable on said wheel head, a grinding wheel carried by said spindle, a work support for supporting a cutting tool to be sharpened and provided with a gauging surface iixedly positioned in a horizontal plane containing the axis of said work support, said work support being movable longitudinally past the grinding surface of said Wheel and also adjustable laterally toward and from said grinding surface, a tooth rest mounted on said wheel head and having a tooth contact point set close to but clearY of the grinding surface of said wheel, the tooth contacting tip of said tooth rest point coinciding with a horizontal line normal to the wheel axis and lying in a diametrical plane containing the axes of said spindle and the grinding wheel, and also including the axis of said work support, and

height setting means for the tooth rest movably arranged on said gauging surface and including aY-feeler element to be brought from an inactive position into a position coincident with said diametrical plane to establish an accurate placement of the tip of the contact point of said tooth rest exactly on center with the axis of a cutting tool in said work support as the vertical altitudinal adjustment of the wheel head is made in the appropriate direction, said tooth rest having bodily movement with said wheel head during adjusting movements thereof both altitudinally and angularly in their respective vertical planes during which the tip of the work contact point of the tooth rest maintains a constant position in relation to the grinding surface of the wheel unaffected by predetermined changes in clearance angles.

2. In a machine for grinding helical cutting tools the combination of a grinding wheel head adjustable for altitudinal movement in a vertical plane and also angularly in a lateral direction in a vertical plane perpendicular to said vertical plane of altitudinal adjustment of the wheel head, a grinding wheel journaled in said wheel head, a cupshaped grinding wheel carried by said spindle, a rotatable work support for holding a cutting tool to be sharpened and provided with a flat gauging surface tixedly positioned in a horizontal plane containing the axis of said work support, said Work support being movable longitudinally past the end grinding surface of said cup wheel and also adjustable laterally toward and from said grinding surface, a tooth rest mounted on said wheel head and having a tooth contact point set close to but clear of said grinding surface of the Wheel, the toothcontacting tip of said tooth rest point coinciding with a horizontal line normal to the wheel axis and lying in a diametrical plane containing the axes of said spindle and the grinding wheel, and also including the axis of said wheel support, and height setting means for the tooth rest movably arranged on said gauging surface and including a feeler element to be brought from an inactive position into a position coincident with said diametrical plane to establish an accurate placement of the tip of the contact point of said tooth rest exactly on center With the axis of a cutting tool in said work support as the vertical altitudinal adjustment of the wheel head is made in the appropriate direction.

3. The combination claimed in claim 2 in which the height setting means `consists of a series of articulated elongated Iarm members, one of the end arms being pivotally mounted on the cutter holding work support and supported lby said tiat gauging surface thereof placed exactly on center with the work support axis and the distal end arm lhaving la flat undersurface accurately aligned with the first-named surface to serve as a gauging surface for the setting of the tooth-contacting tip portion of said tooth rest on exactly center with the `axis of Ia cutter to be ground.

4. The combination claimed in `claim 2 in which the cup wheel has a convex grinding surface transversely of its rim `and with the crown of said surface opposite the tooth contact point of the tooth rest and lying on a peripheral datum circle around the Vend face of the wheel, and a radius wheel dressing device is provided in which the Idressing tool moves in an arcuate path lying in a vertical plane which includes therrotational axis of the grinding wheel and which is generated about a horizontal axis about which the wheel `dressing device is Iarranged to revolve so as to form said convex grinding surface on the wheel with said crown portion thereof correlated to said tooth contact point of the rest.

5. in a cutter grinding machine, the combination of a grinding wheel having an annular grinding face, elevatable `support means for said grinding wheel including a spindle on one end of which said grinding wheel is secured, means for rotating said grinding wheel spindle, a work support reciprocable past said annular grinding face of said wheel and adjustable laterally toward and away from such wheel face, and height gauge means pivotally mounted on a lateralextending portion of said work support and which forms a perfectly flat gauging surface thereon iixedly positioned in a horizontal plane containing the axis of said work support, said gauge means further having a feeler member the underside of which is perfectly liat and disposed in a horizontal plane that exactly coincides with s-aid horizontal plane containing the rotational axis of the cutter to be sharpened, said height gauge means also being articulated and arranged to be swung from an inoperative position vinto Ian operating position to place the feeler portion of such gauge opposite the end grinding face of said wheel to engage the tooth contact point of a tooth rest and there-by position it accurately on center with the rotational axis of a cutter when the grinding wheel support means is manually adjusted vertically to effect such engagement of the contact point of such tooth rest with the nnderface of the feeler member.

6. In a grinding machine, the combination of "a cupshaped grinding wheel, vertically elevatable and vertically angularly adjustable support means for said grinding wheel including a spindle on one end of which said grinding wheel is removably secured, means for rotating said grinding wheel spindle, 'a tooth rest mounted on said grinding whe-el support means and having a tooth contacting portion placed in predetermined fixed relation to the annular end grinding face of the annular end grinding wheel, a work support reciprocable past the grinding face of said wheel and adjustable laterally toward and away from such wheel face, and height gauge means pivotally mounted on a lateral extending portion of said work support and which forms a perfectly flat gauging surface thereon iixedly positioned in a horizontal plane containing the axis of said work support, said gauge means further having a feeler member the underside of which is perfectly ilat and disposed in a horizontal plane that exactly coincides with said horizontal plane containing lthe rotational axis of the cutter to be sharpened, said height gauge means also rbeing articulated and arranged to be swung from an inoperative position into an operating position to place the feeler portion of such gauge opposite the end grinding face `of said wheel to engage the tooth contact point of the tooth rest yand thereby position it accurately on center with the rotational axis of a cutter when the grinding wheel support means is manually adjusted to effect such engagement of the contact point of the tooth rest with the underface of said feeler member.

7. In a grinding machine, the combination as set forth in claim in which the end cutting face of the grinding wheel is convexedly curved in a semi-circular arc to form a convex grinding surface Whose crown faces opposite the tooth contact point of 'the rest and lies on a peripheral datum circle around said end wheel face and a radial wheel dressing device is provided in which the dressing tool moves in an arcuate path lying in a vertical plane which includes the rotational axis of the grinding wheel vand which is generated about a horizontal axis about ywhich the wheel dressing device is arranged 'to revolve so as to form said convex grinding surface on the wheel with said crown portion thereof correlated to said tooth contact point of the rest.

8. ln a cutter grinding machine of the character described, a base having lan upstanding support member; a carriage mounted upon said support member for vertical sliding movement into desired altitudinally adjusted positions, said carriage having a laterally extending arm; an arcuate member affixed to said carri-age arm and disposed laterally thereof in Ia vertical plane, said arcuate member having a longitudinal arcuate guideway; a movable wheel slide including an arcuate support member engaging in and guided `by said arcuate guideway when moved longitudinally therein to adjust said Wheel slide angularly in a vertical plane or to position it horizontally; a cup-shaped grinding wheel rotatable on said wheel `1`0 slide rand disposed in overhung relationship thereto; a tooth rest mounted in an offset position on said wheel slide and adjustable thereon for placement of a cutter rtooth contact portion of said rest ina predetermined fixed position to the annular end grinding `surface of said wheel;

a table mounted on said base 'below said grinding wheel and arranged for movement longitudinally pastsaid end grinding surface of the wheel and also adjustable laterally toward `and from such wheel surface, saidtable including work support means provided with a laterally extending portion having a perfectly fiat horizont-al gauging surface xedly positioned in a horizontal plane passing through the longitudinal axis of said work support means; and height gauge means composed of a plurality of pivotally articulated members including an end feeler element having a perfectly flat undersurface portion, said height gauge means being pivotally mounted by the Iarticulated mem- Iber distal from said feeler element against the iiat -horizontal gauging surface portion of the laterally extending portion of said work support means, said height gauge means being arranged to be swung from an inoperative position into an operating position to place the feeler element of vsuch gauge opposite the end grinding surface of said wheel and above the contact point of `said tooth rest for engaging such contact point and position it exactly on center with the axis of said support means when the grinding wheel slide is manually adjusted in elevation to ybring about engagement of the contact point of said tooth rest with the undersurface of said feeler element of the height gauge.

9. The combination as claimed in claim 8 in which the cup-'shaped grinding wheel has an annular end grinding surface which is convexedly curved in a radial direction of the grinding wheel and presents a convex grinding surface whose crown faces opposite the tooth contact point of the rest and lies on a peripheral datum circle around said end wheel face, and a radius wheel dressing device is provided in which the dressing tool moves in an arcuate path lying in a vertical plane which includes the rotational axis of the grinding wheel 4and which is generated about a horizont-al axis about which the wheel dressing device is arranged to revolve so as to form said convex grinding surface on the wheel with said crown portion thereof correlated to said tooth contact point of the rest.

l0. in a cutter grinding machine of the character described, a base having an upstanding support member; ya carriage mounted upon said support member for vertical -sliding movement into desired altitudinally adjusted positions, said carriage having a laterally extending arm; an larcuate member aixed to said :carriage arm and disposed laterally thereof in a vertical plane, said arcuate member having a longitudinal guideway; a movable wheel slide including an arcuate support member engaging in and guided by said arcuate guideway when moved longitudinally therein to adjust said w-heel slide angularly in a vertical plane, or to position it horizontally; a cupshaped grinding wheel rotatable on said wheel slide and having an annular end grinding surface convexedly curved in a radial direction; means operatively arranged for adjusting and securing said wheel slide in a desired adjusted position to support said grinding wheel in ya predetermined operating position; a table including work support means mounted on said 'base below said grinding wheel and arranged for movement longitudinally past said end grinding surface of the wheel and also adjustable laterally toward and from said wheel surface, said work support means having a flat gauging surface flxedly positioned in a horizontal plane containing the axis of said work `support means; and height setting means for a tooth rest movably arranged on said gauging surface and including a feeler element arranged to be brought 4from an inactive position into a position aligned with said gauging surface to engage and t-o establish an accurate 'T1 placement. of the' tooth contact portion of such tooth restexactiy on center with lthe vaxis uf a cutter supported by said work `support means and as the vertical altitudinal adjustment of said carriage is `made in the appropriate direction.

References Cited in the file of this patent UNITED STATES PATENTS 727,981 Lomasney May 12, 1903 IZ Y Perkins Aug. 1, 1916 Curtis July 11, 1933 Anderson July 18, 1933 Wildhaber Aug. 7, 1945 FOREIGN PATENTS Great Britain Oct. 29, 1931 Great Britain Feb. 17, 1954