US2539506A - Grinding machine - Google Patents

Description

Jan. 30, 1951 w. M. BURA GRINDING MACHINE 5 Sheets-Sheet 1 Filed June 21, 1946 I? W9 76v 8 WALTER MARK EUR/4 Jan. 30, W. M. BURA GRINDING MACHINE Filed June 21, 1946 5 SheetsSheet 2 gwue/wtom 9 WALTER MARK EL/R'A W. M. BURA GRINDING MACHINE Jan. 30, 1951 5 Sheets-Sheet 5 Filed June 21, 1946 ,8 $3 WALTER MARK EUR'A Jan. 30, 1951 w, BURA 2,539,506

GRINDING MACHINE Filed June 21, 1946 5 Sheets-Sheet 4 WAL TER MARK B ZJRA Jan, 3Q 1951 W. M. BURA GRINDING MACHINE 5 Sheets-Sheet 5 Filed June 21, 1946 ml. I WALTER MARK ELJR'A mQN NON

w MS Q W9 www Patented Jan. 30,

GRINDING MACHINE Walter Mark Eura, Washington, D. 0., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application June 21, 1946, Serial No. 678,195

Claims.

The invention relates to grinding machines and with regard to its more specific features to a grinder for grinding cutting tools, bits, milling cutters and the like, especially those having tips of cemented carbide.

One object of the invention is to provide such a grinder which will shape such tools, bits, milling cutters and the like to form desired angles of clearance without the use of a sliding tool holder or the like. Another object of the invention is to provide a grinder of the type indicated which will shape such tools, etc. without the use of any patterns, blocks, cams or the like to control the generated shape. Another object is to provide relief in the direction of the feed (as in a lathe) of the tool, of constant or nearly constant angularity while the tool is rigidly clamped to the table of the machine.

Another object of the invention is to provide a grinder for the generation of relief or clearance angles in which more reliance is placed upon the brains of the operator and less upon the skill of his fingers.

Another object of the invention is to provide a universal grinder that can be set to shape many and various curved surfaces and that has means to provide a feeding component for grinding by increased increments without upsetting the generation or changing the shape of such curved surface.

Another object of the invention is to provide a grinder having some of the above characteristics which may also be used to produce ordinary right circular cylinders, right circular cones or other common shapes. Another object of the invention is to provide a grinder with one or more of the above characteristics which will also function as a surface grinder to grind a plane surface.

Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations 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.

In the accompanying drawings illustrating one of many possible embodiments of the mechanical. features of this invention,

Figure l is an elevation of a grinding machine constructed in accordance with the invention;

Figure 2 is likewise an elevation of the machine, looking from the left in Figure 1;

Figure 3 is a plan view of the machine;

Figure 4 is a sectional view, taken along the line i4 of Figure 2;

Figure 5 is a sectional view taken along the line 55 of Figure 1;

Figure 6 is a sectional view taken along the line 6- -6 of Figure 4;

Figure '7 is a sectional view taken along the line 'i'! of Figure 3.

Referring to Figure 1, the machine has a relatively low and hollow base l0 joinedto a relatively high and hollow base ll which in plan view is of narrow rectangular shape. The base l0, which is approximately square, supports a series of slides and a revolving table, while the base H supports a movable carriage l2. The slides and the rotatable table support the work piece, while the carriage l2 supports a grinding wheel l3.

Referring now to Figure 4, the base Ill has a fiat way I l and a V-way I5 on which are located mating parts [6 and I! of a slide 2! Depending from a table 2| is a large trunnion 22 which is journalled in radial ball bearings 23 and 24. The outer race of upper ball bearing 23 fits with a press fit in a hollow cylindrical portion 25 integral with and depending from the slide 26. The outer race of lower ball bearing 24 fits in a cap 25 which fits in and closes the lower end of the hollow cylindrical portion 25, whereby the ball bearings 23 and 24 are protected from any dust in the base I0. Referring for a moment to Figure l, the cap 25 may readily be reached through adoor 2'! mounted on hinges 23 on the front of the base l0.

Thus the table 2| is journalled in the slide 20 for angular adjustment thereon, or for rotation or oscillation as may be desired. The weight of:

three ball bearings, 23, 24 and Eli are coaxial and the construction described journals the table 2 I for angular movement with very little effort about a fixed axis with substantially no play or lost motion.

The table 2| has a flat way 35 and a V-way 36 upon which rest the'mating parts 31 and 33 of aslide is. Referring now to Figure 6, the slide 46 has a flat way 4! and a V-way 42 upon which rest the mating parts 43 and M of a table 45. The table 45 is a slide because it is movable on the ways ii and 42; it is also a table to hold a work piece or a fixture for holding a work piece, as may be desired. To that end the table A5 has a T-slot it in the upper surface M thereof which is otherwise flat and horizontal.

there is a 'l-Sl0t 5!. By means of the T-slot 46 any tool holder or other fixture, and certain work pieces may be rigidly clamped to the table 45.

Likewise in one side surface 56, which is otherwise fiat and vertical.

The T-slot I adjustably holds a dog 52 the purpose of which will be later explained.

Referring now to Figures 1 and 2 on the front of the machine is a handwheel 55. This handwheel 55 is secured to the front end of a screw shaft 55 which is shown in cross section in Figure 4. As shown in Figure 2 a collar 5! is secured to the screw shaft 55, and the collar 5'! abuts a thrust bearing 58 through which the screw shaft extends and in which it is journalled. The bear in; 58 is attached to the front of a box 59 fastened to and extending forwardly 'from the front. of the base I0. In the box 59 is a collar, not shown abutting the other side of the bearing '58.' Thus the screw shaft 56 is held against axial movement. It passes through a pair of nuts 60, only one of which is shown inFigure 4, which nuts are formedin'tegral with the cylindrical portion '25. The nuts 60 arefai'rlythin and can be flexed toward each other by a bolt 6| in order torernove play between the 'nuts and the screw shaft 56. By'tur-ning the handwheel 55 the slide 20' can'be moved, and also accurately adjusted. The slide 40 is similarly adjustable and movable'upon the table 2| and likewise the table45 is adjustable and movable upon the slide 40. As

shown in Figures 1, 2, 3, and 4 there is a hand wheel @5 on one "end of the slide 40 which is fastened to a screw shaft 66 'which passes through a nut G Tsecured to the table 2 l. The screw shaft 66 journalled in a "thrust bearing, including a collar 68 fastened to the shaft 66 and a part 69 of theslide40.

Referring now to Figures 1, 3, and 4 there are a pair of hand wheels 10 secured to the ends of ascrew sha'ft H which'is journall'ed in depending portions "I2 of the table 45. 'Collars I3 and 14 hold screw shaft II against axial movement relativeto the table 45' Screw shaft 'iI passes through a nut I5 which extends upwardly from andis formedintegrally with the slide 40.

""It is important't'o be able to lock the revolving table 2I in any desired angular position. To this endfas' shown in Figure 4', I provide a lever I6 journalledon 'a stud'll, the lever 16 having a partiallgear 123 formed thereon which meshes wane gear 19 which is secured to a shaft 80' upon which is a cam BI. When the lever 16 is turned, cam 8.I is rotated and wedges the table 2|.

It. is also desirableto be able to set the table- ZI at a given angle 'without the use of instruments. To that'end on the conical surface 84- of the table 2ifare a number of lubherlines 85 andupon the conical surface 860i the. slide 20 are scale marks. Further, to facilitate the setting of the table 25, I providev a T-slot 88 for adjust'ablev securing a number of dogs 89 which. have, arms 90, pivotally mounted at M. These arms 90, when lowered, engage the upper endlof a" stop. 92 extending upwardly from the cylindrical. portion 93 of the slide 20. This cylindrical portion 93 of slide 20 merges into the conical portion 86. 9:2 is shown in the drawings, but several dogs 89 and arms. fliimay be provided and, if desired, more thanone st peZ. The dogs 89 are movably mounted on T-bolts 94 which extend into the 3-519 5 Referring now to Figure 3, means are provided accurately to adjust the position of the slide 20. A bracket 95 is secured to'the base I0 and has an open slideway 97. secured a dial micrometer gauge. 98. Blocks 99 mhylbe placed in the slideway 91, these blocks being of designated length to ver close toler Only one dog 89, arm 90 and stop.

To the bracket Edis.

ances. A dog I00 located in a T-slot, IOI, Figure l, in the slide 26 engages either a block 99 or the needle'of the dial micrometer. gauge 98 and thus the slide 20 may be adjusted to various exact positions and readjusted by small increments. ""Similarly the dog 52 in the T-slot 5| of the table45 may engage a block I02 in an open slideway I03 of a bracket I04 attached to the slide 40, or it'may engage the needle of a dial micrometer gauge I05, for the accurate adjustment of the table 45. 7 7

Referringnow to Figures 1 and 5, the high hollow base II has a dovetail portion IIO on the top of which is a flat slideway I I I. Opposite this dovetail portion H0 is another dovetail portion II2' likewise having a' fiat slideway H3 on the top thereof; The carriage I2 is a hollow rectangle in cross section and the lower "wall I I4 thereof has a smooth plane surface on the bottom which rests upon the slideways III and I I3. 'E'xtending downwardly from the ends ofthe lower. wall H4 are outerdovetail portions [I5 and H6 which 'mate with the dovetail portions II-Uand II 2. Gibs II? adjusted bybolts H8 complete the slideway for the carriage I2 which can thus move freely on the base II in 'a straight horizontal line but is firmly held from any side'motion. The carriage I2 may also be locked rigidly in position bymeans of a sCreWIZU extending through a stationary nut I2! extending downwardly from the top wall I22 of the carriage I 2, as the screw I20 abuts alever I 23 which is mount-' ed on a pin I24, and the lower end'of the lever engages a gib HT. "'I'he pi'n I24 is held by ears extending from the sidewall 525 and the bottom wall H4 Referring now to Figures 5 and '7, bolted to thelower wall I I4 by means of bolts I20 is a casting: I29. This castingI2'9 holdsa cylinder I30 in which is apiston ISI connected by hollow piston rods I32, to brackets I33 which are hollow and admit and exhaust fluidto and from the hollow rods I32. The brackets I are mounted on the base I I and have the double of: holding the rodsl 32 and transmitting fluid. The carriage I2 can be automatically recipr ocated by means of the piston and cylinder unit I3I and; I 3 0 which can be controlled by a rever'slinglever I34 (Figure l) pivoted at I25v which is engaged by. reversing dogs I35 adjustably mounted in a, T-slot I31 on theosicle v of, the carriage I2. The speed of travel of the, carriage [2 can be adjustedby means. of a knob l't flwhi'chisturned to change the setting of a valve, and the carriage can, be started and stopped by means of a lever I39 which, pulls the knobT-jid; out or pushes it. in. The various valves and the hydraulic diagram are. not. herein disclosedbecause such are now well known inthe art I prefer to usethe. Norton hydraulic system as disclosed, for example, in U. S. Patent No.. '2, 0. 71, 67' '7, which is hereby incorpo ed by r ference. i

Sometimesit is desirable. to .mOYQithe carriage I2 by hand. Referring nqwto Fisureb, theidove tails 1m and H2, areconnected y, castinsnorr. tion I40 which is a,v U-shaped inIcross, section and in one side wall of which are boresfor a shaft I andra stud I45. Ontheshait I45 are spur gears I41.and I48, the.,f,Qlfr ner' eshingwith a rack I which is fastenedto thecasting I29. Gear I48, meshes with a gear .I'5I'on"the stud I45, and gear I5I meshes with gear I52. The gear I52 has a clutch portion I53 which can be'engaged by a clutch portipn l54on thejend, of a hub I55 of a handwheel I56; Thehub I55 5, is slidably and rotatably mounted in a bore I51 in the front wall of the high hollow base II. Through the hub I55 and through the gear I52 and into a bore I58 in the casting portion I40 extends a shaft I59 which abuts a spring I60. When the handwheel I56 is pushed, the clutches I53 and I54 engage, and then by turning the handwheel I56 the carriage I2 can be traversed on the base II. The spring I60 automatically disengages the clutches I53 and I54 when the handwheel I56 is released. A pin I6I extending into a groove I62 in the hub I55 prevents the handwheel I56 and shaft I59 from being accidentally removed from the machine.

Referring now to Figures 1, 3, and 7 on the front of the carriage I2 are a pair of dovetail portions I65, I65 forming a slide way upon which is mounted a vertically movableslide I66 having co-operating dovetail portions I61, I61. Gibs I68 and bolts I69 are provided for the joint purpose of eliminating lost motion and locking the slide I66 in a desired vertical position.

On the side of the carriage I2 is a handwheel I which is secured to a shaft I1I which is suitably journalled in the carriage I2. The shaft III extends into a hollow box portion I12 formed in the forward part of the carriage I2. This box portion I12 includes a separate casting I13 in which are formed upper. portions of the dovetail portions I65. This separate casting I13 is provided for purposes of assembly. The box portion I12 on its lower side supports a ball thrust bearing I15. The casting I13 receives the thrust of a ball thrust bearing I16. These bearings I and I16 support a sleeve I11 having formed in the center thereof a worm wheel I18. With this worm wheel meshes a worm I19 which is keyed to the shaft I1I.

The sleeve I11 is internally threaded and receives a screw shaft I80, the top of which is fastened by means of a nut I8I and washers I82 to an overhanging portion I83 of the slide I66. It will thus be seen that the slide I66 may be raised or lowered by turning the handwheel I10 and it may be locked in position by tightenin the bolts I69.

Referring now to Figures 1, 2, 3 and 7, on the front of the slide I66 is an integral hollow trunnion I85 (see especially Figure 2) journalling a split bearing I86 of a wheel head support I81. A hand lever I88 is fastened to a vertical shaft I89 which extends through integral bosses I90 and I9I formed on the split bearing I86 on either side of the split. The shaft I89 is free in the boss I90 but in screw threaded engagement with the boss I9I. Therefore the bearing I86 may be tightened upon the trunnion I85 to lock the parts together or may be loosened to adjust the wheel head support I81 angularly about a horizontal axis, by moving the lever I88. A lubber line I92 is provided on the bearing I86 and scale markings I93 are provided on the trunnion I85 in order to adjust the wheel head support I81 to known angles.

The wheel head support I81 extends away from the trunnion I85 and terminates in a hollow bearing I95 the tranverse plane of which is practically tangent to the trunnion I85. Furthermore, when the zero mark of the scale I93 is on the lubber line I92 this transverse Plane is horizontal and the axis of the bearing I95 is vertical.- A trunnion I95 of a wheel head I91 fits in the hollow bearing I95. The wheel head I91 supports a motor I98 which drives a shaft I99 journalled in a bearing 200 in the wheel head I91. The

grinding wheel I3, which may be a cup wheel as. shown, or may be a peripheral wheel or of any other shape, is fastened to the shaft I99.

The trunnion I96 is held in the bearing I95 by means of a bolt 202 which extends through a boss 2% formed in the wheel head support I81 and into a threaded boss 284 in the center of the trunnion I96. The bolt 202 may be loosened to adjust the wheel head I91 angularly, and tightened to secure the adjustment. It will be noted that there is room to swing the wheel head I91 through a full circle in some positions of the wheel head support I81. The former has lubber lines 205, and the wheel head support I81 has scale markings 206 in order accurately to determine the angle of adjustment of the wheel head I91. When the zero of the scale markings 206 is on one of the lubber lines 205, the axis of the wheel I3 is perpendicular to the slideway III, II3.

In order to grind a single point tool such as a lathe tool which will have relief or clearance angles in the direction of feed of the tool into the work it is to out which are of nearly constant angularity, I provide a tool or work holder (not shown) which may be rigidly secured in the T slot 46 in the surface 31 of the work table 45. Such a work holder will be capable of holding the tool to be ground in any angular position. I place the tool in the tool holder and position it so that the shank of the tool is normal to the direction of feed of table 65. In order to grind the side under the side cutting edge to the required relief angle, that is, the side longitudinal of the shank of the tool, I index the wheel I3 to zero by moving the wheel head I91 about its vertical axis until the lubber line 295 comes op-. posite the zero mark of the scale markings 206. In this position the axis of the wheel will lie in a vertical plane which is parallel to the direction of infeed of the lowest table 20. I then tilt the wheel I3 to the angle to which I wish to grind the relief under the side cutting edge of the tool by moving the wheel head I81 about the, horizontal trunnion I until the lubber line I92 comes opposite the angle of tilt I desire on the scale I93. The face of the wheel I3 will then lie in the required angle from the vertical. To obtain the desired angle of relief under the front cutting edge of the tool to be ground, I tilt the tool from the horizontal through an angle which is the difference between the side and front relief angles required by adjusting the holder. To form a radius at the corner of the tool wherethe cutting edges meet, I back away the lower cross slide 20 from the wheel face by means of wheel 55, until the center of the table 2I is away from the wheel face by the amount of the required radius, as indicated by the dial micrometer gage 98. The radius will also depend upon the height. of the tool edge with respect to the wheel face because the wheel has been tilted. This has been taken into account when the micrometer gage 98 is indexed. I then set the revolving table stops 89 so. that the table ZI will swing the tool through an angle at one limit of which its side cutting edge is pre sentcd to the face of the wheel I3 and at the other limit of which its front cutting edge will be presented to the face of the wheel I3. In setting the limit stops 89 I determine the limits of. the angle of swing of table 2i to adjust the stops 89 by bringing the lubber line 85 opposite the proper readings on the scale 86. I feed the tool longitudinally into the wheel to present the front cutting edge by advancing the table 40 with the wheel 65;

and I feed the side cutting edge in by advancing the cross slide 45 with wheel toward the wheel l3 when the side cutting edge is turned toward the wheel face. To grind the radius where the cutting edges meet I revolve the table 2! between the stops 89. The amount of stock to be removed depends upon the amount I feed the tool into the wheel I 3 by the tables 40 and Q5 or the re 'sultant' of these motions. No matter how much I feed the tool into the wheel I3 by advancing tables 40 or 45, I will grind the same radius and the same side and front cutting edge relief angles for which I set the machine up. Feeding in the tool by moving the tables 46 and 4% simply causes more stock to be removed, but the resulting shape of the cutting edges of the tool will remain the same. It will be seen that by rotating the tool upon the table 2| against the face of the wheel l3 as I grind the radius, the predetermined relief angle-under the side cutting edge of the tool automatically changes to the angularity I have set for the relief under the front cutting edge of the tool.

To grind a multiple toothed tool such as a peripheral and face mill to obtain constant ang ularity of relief in direction of feed (of the tool toward the Work it cuts) I provide a work holder which is capable of holding the shank of such a cutter tool to the wheel face at any angle, and I clamp it to the Work table 35 by means of the T slot 46. I place the tool therein, so that its shank lies horizontally and in a vertical plane which is at right angles to the direction of feed of the Work table 45. I index the wheel is about its vertical turning axis to zero as before, so that the wheel spindle lies in a vertical plane which is parallel to the tableway 2B, and I tilt it about its horizontal axis to the angle of relief (from the vertical) I desire the face of the tool to have. I then rotate the table 2| to position the face cutting edge against the wheel by advancing table so by means of wheel 65. I limit the rotation of table 2! at this position by setting a limit stop 88. I then rotate the table 2| to present the peripheral cutting edge of the tool to the wheel face by advancing table 45 with wheel 78' and I limit rotation of table 21 to this position by setting another limit stop 89, so that the table 2! can now rotate between these two angle limits to grind the face, the radius and the peripheral side of the tool in one pass. In order to further support the tool while it is being ground a tooth rest (not shown) integral with the wheel head is provided to support the particular tooth being ground from beneath at the point of grind. To grind the angle of relief desi'redon the peripheral face, the tooth rest is adjusted up or down (as the set up indicates) the tool is rotated on its axis through an angle which is equal to the difference between the two cuttin edge relief angles I desire. I back the table 21 away from the face of the wheelv 13- on its slide 29 by means of feed wheel 55 so that its center lies away from the wheel face anamount equal to the radius I Want at the corner between the face and peripheral cutting edges of the tool. This will produce the required angle of relief under the peripheral cutting edge. For example, ona cutter tooth requiring 3 relief in the face cutting edgeand 7 on the peripheral cutting edge, the wheel would be tilted 3 from the vertical and the tooth rest lowered through an angle of i. The change from: one angle to the other is accomplished automatically as the table 2;! is rotated between the limit stops as as set to grind the radius, which results in: the shape of a right truncated cone on the corner where the radius is ground. I

"These two illustrations of the machine operation describe functions for which this machine is particularly well adapted. In surface grinding the wheel 13 will automatically traverse the work as it moves on its hydraulically driven carriage I2, while set at any angle of tilt desired. Infeed is controlled by the movable tables as described above, and depth of cut by the wheel I10 to lower the wheel vertically. The seven motions in the machine to control movement of the wheel and the work (exclusive of work positioning by means of a tool holder not shown) relative to each other together with micrometer gages allow controlled grinding of an infinite number of shapes without the use of templates, patterns, cams or the like.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved.

As many possible embodiments may be made of the above invention and as many changes might bemade in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth (or shown in the accompanying drawings), is to be interpreted as illustrative and not in'a'limiting' sense.

I claim:

H 1. In a grinding machine, a base, a slide direct ly upon said.- base, a rotatable table directly upon said slide, a second slide directly upon said ro tatable table, a third slide directly upon said second slide movable at an angle to said second slide, a second base connected to said first base and extending above it, a horizontally sliding carriage on said second base, a vertically movable slide on said sliding carriage, an angularly adjustable wheel head support on said vertically movable slide adjustable about a horizontal axis, and a; wheel head carried by said wheel head supportand angularl y adjustable about an axis normal to the axis of said wheel head support, the wheel head being over the table whereby a grinding wheel mounted thereon may operate upon a Work piece held by said third slide.

2. In a grinding machine, a base, a slide mov: able on said base, a hollow cylindrical portion extending downward from said slide into said base, a table, a downwardly extending trunnion under said table, means for journalling said trunnion in said hollow cylindrical portion whereby said trunnion is angularly movable, additional thrust bearing means between said slide and said table for supporting said table from said slide, a slide carried by said table which is movable in a plane perpendicular to the axis of said trunmen, and a further slide on the slide carried by said table, saidfurther slide being movable in a plane parallel to but in a direction at an angle to'the slide carried by the table.

3. In a grinding machine; a base havinga' low portion and a portion, a horizontally sliding carriage mounted upon said high portion, a vertically'movable slide carried by said carriage, a wheel head support journalledon a horizontal axis in said slide; a wheel head journalled in said support on an axis normal to said horizontal axis, a slidemounted directly upon the low portion of said-base, an-angularly adjustable table mounted sheen-yon: said slide which is upon the low por tion ofsai d base, and a pair of slides one above the other on said table, said slides on said table 9 being movable at an angle to each other but in planes parallel to each other, and the wheel head being over said table, whereby a grinding wheel carried by the wheel head can operate on a Work piece held by the top slide of the pair of slides one above the other on said table.

4. In a grinding machine as claimed in claim 3, the combination with the parts and features therein specified, of means for feeding each of said slides.

5. In a grinding machine as claimed in claim 3, the combination with the parts and features therein specified, of means for accurately locating said table and means for accurately locating one of said slides.

WALTER MARK BURA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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