US2374716A - Grinder - Google Patents

Description

C. A. WlKEN May 1, 1945.

GRINDER Filed Feb. 28, 1942 5 Sheets-Sheet l C. A. WIKEN May 1, 1945.

GRI NDER Filed Feb. 28 1942 5 Sheets-Sheet 2 gnaw/Whom cmvsii a. VV/Aen,

v WM

WIN

May 1, 1945.

C. A. WIKEN GRINDER Filed Feb. 28 1942 5 Sheets-Sheet .3

- 6/2/7573 ,4. VV/A en,

fluqww y 1945- c. A. WIKEN 2,374,716

- GRINDER Filed Feb. 28, 1942 5 Sheets-Sheet 4 Patentecl May 1, 1945 UNITED STATES PATENT OFFICE. 2,374,716 U GRINDER Christy A. Wiken, Milwaukee, Wis., assignor, by"

mesne assignments, to The Delta Manufacturing Company, a corporation of Delaware Application February 28, 1942,.SerialNo. 432,847

14 Claims. (01. 51-409) The present invention relates to grinders intended for convenience in grinding tools, especially tools which are provided with cutting tips including tungsten carbide or similar extremely hard material. Such tools are used extensively at present, and usually consist of shanks or body portions of steel, having the hard cutting tips secured thereto, asby welding or sintering.

The grinder is preferably designed to run at a high speed, say approximately double that of the standard four-pole 60 cycle alternating current motor, the grinding wheels being carried direct- 1y at the ends of the motor shaft, the wheels being of such size as to give a surface speed of the order of a mile a minute at the cutting location.

Preferably the two wheels are of different coarseness of grain, and contain silicon carbide or other abrasive material of equivalent or even greater hardness, for example diamond.

The grinder is preferably made by providing a special base, directly on the frame of the motor, or constituting a part of the frame of the motor, this base or pedestal being of sufficient height to raise the shaft of the motor enough to allow the grinding tables and waste receiving troughs to be manipulated from their under sides when the pedestal is mounted upon an ordinarywork table or bench. A special floor pedestal is also provided which will take the place of a work bench and cooperate with the grinder base to raise the machine to a suitable height when the pedestal is mounted directly on the fiooizt The work'tables and waste receiving troughs are preferably made as unitary assemblies wherein the trough portion is secured :tothe motor frame or pedestal in such way that it ma y be slid in and out in a direction parallel to the axis of the grinder shaft and clamped at a selective position, so as to bring the table carried thereby to the desired spacing from the side of the wheel;

tilting in both directions, that is toward and from the wheel, through a'relatively large'angle and a groove preferably is provided in the table top to cooperate with a grinding gage having a tilting graduated head, togguide said gage in a directicn parallel to the cutting face of the wheel while holding the tool at the correct angle to the said surface.

Means of electrical nature are provided for starting and stopping the motor, preferably such that the direction of rotation may be reversed when desired. This makes it possible to grind high speeds, and, because of the ball-bearings,

if left to themselves would spin for an annoyingly long time, before the operative could reverse the rotation. A simplebut effective brake has therefore been devised, to dissipate this momentum when necessary. I

A waterpot is provided, having means whereby it readily may beheld securely adjacent either wheel, but yet is removable instantly without loosening any screwor other securing means, so"

that the pot easily may be removed bodily for filling, emptying or cleaning or for shifting it to the other side of the grinder. This pot-has'an outlet tube having abent discharge end, anda I stop cock for controlling the rate of flowof the water or other liquid, the grinding wheels prefer-' ably being of the recessed type so that thefbent discharge end of the outlet tube may enter into the recess of either wheel.

A feature of the inventionis to provide remove ably mounted sludgepans carried adjustably by the end frame of the motor, which alsoconstitute wheel guards. These pans in turnhave integral elevated portions therein for supporting the table I trunnions and other raised portions whereby the pans are secured to the end frame. By this means the machined surfaces of the pan are raised above the level of the rim of the pan so that no liquid collected in the pan can reach them, thusassuring against corrosion and soiling of the tr'unnions and the supporting surfaces of the pans.

A further feature of theinvention 'is to provide a guide bar for the toclbeing grouncbsaid guide bar being secured adjustably to the grinding gage. This is preferably accomplished by sel curing the bar to the gage by means of one or Y more screws, passing through a slot 01' slots in i the bar.

By this construction, the end of the bar may be brought close to the grinding wheel 1 even when the gage is tilted to a relatively great angle, so that'the tool may be guided and supported more precisely.

A light fixture preferably cooperates with; the

grinder and is pivoted at a point substantially,

vertically above the center of the motor frame.

It comprises a flexible tubular conduit carrying a lamp socket and shade at its outer end, and

four grinding locations without bending or othering' locations are equidistant from'the'pivot'.

wise adjusting the conduit, since these four grind From the above summaryof objectsand s'tr-u'o tural features of the grinder, it will be clear that the general'object is to provide a high speed. reversible grinder havingmeans-for guiding thev article-to be ground at a definite angle tothe cutting surface" of the wheel, while supplying a 3 coolant such as water thereto,-providin-g also a 1 source of illumination which maybe shifted to understood that the pedestal 2 need not be used, when a work bench or other support is available, in which case the base I may be mounted directly on suchbench or the like. The pedestal 2 however affords a convenient means for supporting the grinder as it may be secured to the floor whereverdesired if the installationis to be permanent, or may be moved-about as-preferred if not-fastened to the floor. The column 'orpedestal 2 thus affords ready access to all sides of, the grinder which may be an advantage in some instances. I

The base I difiers from the bases customarily found on electric motors in that it is much taller so-thatitraisesthe motorshaft sufficiently high to accommodate the necessary mechanism between the ,grinding.wheels and the, top of thecenter of its stroke, the positionishcwnin Fi 1,

and providing opposite directions of rotation of the motorshaft when thrown to theizright or practically any desired position to illuminate the work,"means being also provided to catch any dripping or sludge and so arranged that'they 1 emptying and cleaning.

Otherobjects and advantages of the'invention s in part will be particularly pointed out by reference to'a specific form; of the invention selected j as an example and'described and illustrated in 1 the present specification and the drawings acj companying thesame, and in part will-bebbvi- 1 ous'from the saiddisclosure. I

1n the drawings:

Fig, 1' is a perspective elevation of the machine mountedupon an individual-pedestal;

Fig! 2 is .a partly broken-away end view ofthe I grinder onan enlarged scale, without the pedestal, as seen from the right in F'lg. '1;

- may readily be removed from the machine for s Fig.3-is a front elevation of the machine shown 1 in'Fig. 2;-

Fig. l-is an end-elevation of the machine from 1 the same end as that shown in Fig. 2, partly broken away; I

Fig. 5 is a fragmentary elevation partly broken away and in central section along avertical plane guide adapted to cooperate with the workholding 1 left of said 01f position. The motor shaft N (Fig. 2, etc.) carries the two recessed or annular grinding wheels 9 and lll atwits ends, these wheels.

being preferably of' materially difierent grits, so.

that one will serve for. rapid cutting while the or rearward portionof' each wheel, since it is customary to grind only .on the descending por-' tion of an abrasive'wheel to prevent the wheel from lifting'the' work piece from the work table and thus causing inaccuracy or chatter.

' Each wheel has a work table, |.2.or l3, cooperating therewith, thesetables being: mounted on elev'atedtrunnions M carried: by the sludge pans l5- located below the" respective tables and adapted'togreceive dripping and waste from the grinding. At the front each table has a scale I6 cooperating with :a pointer l 'l to;indi

angles ordinarily encounteredinthe tools to be ground, for example a tilt of 30? toward the wheel and away from the wheel.

In order'toguide the pan l5 andconsequently the table and'other elements carriedthereby; when the pan slidestowardor away from the grinding wheel as above stated,'an-integral raised tables of the grinder, theguide bar being artly broken away; Fig. 7- is an exploded view showing a portion of 1 v the frame of'the grinder and a. drip pancooper ating therewith; and v Fig. 8 is a fragmentary detail, with parts in Referring first to Fig. 1 there is shown a' motor 3 provided with a base or pedestal l which in.

turn is mounted on the relatively tall pedestal I or column 2 and secured thereto by any suitable, fastenings such as the cap screws '4. It will be portion 96 is provided in each pan; asbestshown in Fig. 7. This raised portionhasan upper surface Iil2'which'is substantiallyplane and-normally. is in contact with the corresponding plane to the raised portion 9.6 :by'means'of a screw me passing through a counter-sunk opening 99 in the key and threadedintorthe portion 96, 'where' by the upper: portion of: the key 198' will be :re-

ceived in the cooperating groove lfllof the frame 2.4.

Other grooves such as I04 and I05 may be provided in the original castings, the adjoining surfaces of the pan and the frame, so that less material need be machined in forming the coacting guide surfaces on said elements.

Each pan I5 has a discharge opening 95 (Fig. 2) in the bottom thereof into which is threaded a plug 88, which may be a standard pipe plug. This permits draining the contents of the pan I5 when desired, but preferably the entire pan will be removed bodily from the grinder at intervals, to permit flushing and cleaning, which is much more satisfactorily accomplished by holding the entire device under a stream of water which will carry away all the sludge, etc.

Each pan is secured to the frame 24 of the grinder by means of studs 89 threaded through the frame and extending downward through open-ended slots 94 in the pan. As shown, each stud has at its upper end a lock nut 98 and at its lower end a nut 9|, a washer '92 being interposed between the nut 9| and the fiat bottom portion 93 of the pan.

Upon loosening the nuts 9|, the entire pan i5 is free to slide toward or away from the grinding wheel, and may be adjusted to the desired spacing from said wheel to hold the table in correct position for the work to be done, or may be slid out entirely for emptying and cleaning. Upon tightening the nuts 9| the pan will be retained in any desired position of adjustment.

As already mentioned, the bearings 2| extend above the level of the top of the pans, thus keeping the trunnions I4 well above any possible sludge or liquid in said pans, and likewise the surfaces I02 and I33 are maintained above said sludge.

Each of the tables, I2 and i3, which are alike in all respects except that the scales I6 are at opposite ends with relation to one another, has a slot or groove I8 therein for guiding a grinding gage which will be described later and also has a rectangular portion I9 cut away so that the table may surround the end surface as well as the front and rear of each wheel 8 and I0. The edge 2|! of this opening I9 is preferably sub stantially coincident with the axis of tilt of the tables so that when the tables are tilted the said edge 29 will remain practically at the same dis tance from the end surface of the corresponding wheel.

The trunnions M are supported on journals or bearings 2| integral with or attached to the pans I5, and clamping means 'are provided, in the form of bolts 22 passing throughthebearings 2| and to the inside of the trunnions M, with a star wheel 23 threaded on each bolt for clamping the table in adjusted position, as will be described in greater detail later.

A shield 24 is provided at each end of the motor 3 and serves the triple purpose first, of guarding the abrasive wheel, second, providing a support for a water pot 25 which has a preferably brass rod 26 projecting downward therefrom to be received in an opening 21 in a lug 23 provided on each shield 26, and third, supporting the pans and tables. The shield of course also constitutes an integral part of the motor bracket or end plate, which supports the shaft bearings.

The bore 2'! preferably is tapered and a corresponding taper is formed at the end of the rod 25 to provide a satisfactory fit. An outlet tube 29 extends from the water pct 25 and is in communication with the interior thereof, and is-bent at its end as shown at 30 to enter the recess in either wheel 9 or ID, a stop cock 3| being provided to control the flow of liquid through said tube 29.

An advantage of this construction is that the I tapered joint between the water pot and the shield 24 provides a joint which always holds the pot securely and firmly, the friction of the .ta-'

terminates in a fitting 33 from which extends a flexible conduit 34 carrying a lamp socket and lamp shade 3B. The conduit 34 may be bent at will to bring the lamp carried-in socket 35 to a suitable position to illuminate the work piece and a pivot joint is provided in the fitting 33 whereby the companion fitting 31 at the end of the conduit 34 may rotate through substantially 360, but is restrained from turning beyond a full turn in either direction, so that the electrical conductors passing to the lamp through the conduits 32 and 34 cannot be twisted off accidentally by continued rotation in one direction. By thus providing substantially 360 rotation, the lamp may be brought to any required position withoutdanger to the wiring. For example, a pin I06 on the stationary fitting 33 may coact with a pin I01 on the fitting 31, to limit the rotation as stated.

Passing now to Figs. 2 and 4 there is shown a lamp 4| controlled by switch 42 and mounted in socket 35, the lamp being fed through the electrical cord 33 passing through conduits 32and 34and having the attachment plug at its free end.

While many advantages may be obtained from the illuminating device just described,'additional advantages result when the pivot-fitting 33 is 7 located substantially vertically above the, center of the motor. In this position .it is obvious that the conduit 34 need be 'bent only once to the proper shape to bring the lamp 4| carried in the socket 35 to the correct position adjacent each of the four locations at which grinding will be done, namely, near the front and rear of each. wheel, This is true because of the symmetrical arrangement of the wheels and tables with respect to this location of the pivot for the conduit, namely a pivot which is equidistant from the four work stations. l

Figs. 2 and 4'show clearly the arrangement of the two journals 2| for the trunnions III of table I3, the bolts 22 xtending through bores 43 in said journals with their heads within the trunnions so that tightening the star wheels 23 will draws'aid trunnions firmly against their bearings, to clamp the table I3 in any adjusted pov sition. l v I It will be noted that the table trunnions I4 are maintained entirely above the level of the top of the pan I5, because of the bearings 2| rising from the bottom of said pan and extending over the top thereof. This keeps any liquid or sludge in the pan from seeping into the joint between the'trunnion l4 and its bearing 2!. I

The under surface I03 of the shell 24 likewise is maintained above the sludge level by reason Fig. 2 shows the tapered end 38 of the rod 26 This keeps thev prises afiat bar 46 guided slidably in the groove l'8..and fitting interchangeably in either table l2 The. gage comprises a head 41 pivota-lly mount-' ed' at 48 on the guide bar 46 'whichslides in one of the grooves H3 in the tables. This pivotal connection is here indicated as provided by a lug or pin 48' on one of said members rotatable in a corresponding hole in the other member. The head 41 has a slot 49 therein, preferably formed as an arc concentric with the said pivot and a screw 50 projects downward through said slot, and is threaded into corresponding threads in the 'bar 46. It preferably has a knurled head 5|, for convenient manual operation. I

An inclined surface 52 is provided at the front of the head 41, and carries a scalefiE which thus may be'read either from above or from in front, by means of a pointer 54 secured to the bar 46 by a screw 55 or other suitable device, whereby a slight degree of adjustment of the pointer is made possible to permit setting the reading point accurately.

At its rear the plate 47 preferably has an upstanding flange, 56 which may serve directly as a guide for the toolsbeing ground in manycases. It will be noted that when the flange 56 is at rightangles to the guide bar 46, or not far from such right angle position, the end of the flange 56wi'll approach fairly close to the cutting surface of the wheel, and thus will afford firm support for the work piece.

- However, when the flange 56 is inclined at a much smaller angle, the end of the same will not approach closely enough to the grinding surface to afford adequate support for the tool, and in such cases it is advantageous to provide a supplemental guide for the tool, consisting of the plate or bar 51 which is longer than the flange 56 and is-secured flat against said flange by means of the cap'screws 58.

The bar 51 thus constitutes a substitute guide, and of course is made of uniform thickness so that its outer surface will beparallel with the guiding surface of the flange 56. The screws 58 will pass through the openings 59 in the flange 56, which are elongated-so that when the screws are loosened, the 'bar 51 may be moved toward or away from the wheel.

It will be noted that the grinding wheels prefsockets 65 therein for engagement with a polygonal wrench, are preferably provided for holding the wheels in place. Each flange BI is secured toa corresponding end of the motor shaft H- in any suitable manner, as-by means of a Woodruff key 66 engaged in an arcuate depression in the shaft II and extending into a keyway 6'! in the hub of the flange 6 I, each end of the shaft prefer ably being reduced in diameter and threaded as indicated at 68 to receive a round nut GSeXtend ing into a corresponding bore 10 in the flange, i

' trance of foreign mattersaid nut having aslot l I- therein so that it may be tightened by a suitable spanner.

As stated, the conical surface 63 provides means for braking the wheel. Thisis accomplished by forcing a wedge '12 against said conical surface. It has been found that a wedge made of suitable hard-wood, for example maple, is very satisfactory as a lbrake block. As inclined surface i3 is provided on the stationary part 24 of the motor frame, and the opposing surfaces of the wedge 12 are substantially parallel with surface 'l 3and surface 63 of the cone respectively, so that when the block 12 is depressed it will bear against both said surfaces.

It has been found desirable to incline both surfaces of the wedge to the vertical, so as to increase the angle of the wedge, in order to'prevent gripping, as otherwise difficulty might be experienced in causing'the brake block to release the wheel when the braking has been accomplished. The block 12 has a portion 14 extending out of a, hole 15 in the casing 24, and preferably has a shoulder 6 to engage the under surface of the casing around said hole 15 when in its released position. I

In order to hold the brake block 12 normally in its uppermost or disengaged position, it is provided with a bore 71 in which is housed a spring '58 bearing againstthe upper end of the bore and bearing'also against a projection 19 formed on the casing 24, the brake block being slotted at its lower end so as to straddle the lug 19, which therefore serves both to guide the wedge block 12 in its motion and to prevent turning thereof, so that the wedging surfaces will always be in. proper position for service.

The motor frame 24 is formed with a projecting boss 8! bored to receive a ball bearing 80, preferably of the type which is originally provided with sufiicient lubricant to serve throughout its life, and sealed againstloss of lubricant or en- A further protection for the bearing is provided by the flanged ring 8-2 surrounding the hub 83 and secured to the boss 8| by screws 84 as indicated.

This ring 82 carries a closure of flexible and plialble material, such as oil-impregnated leather 85 bearing lightly against the hub 83 to prevent entrance of grit or moisture. The ball bearing 80 is retained against a seat 81 in the boss 8| by means of the externally threaded ring 86 which is screwed into corresponding threads within the boss as shown in Fig. 5.

While the motor illustrated conventionally is of the induction type, it will be understood that no restriction is placed, upon the nature of such motor. which equally well may operate on any type or voltage of electrical energy.

Instead. of using the brake block 12 shown in Fig. 5 and hereinbefore-described, an alternative form may be preferred and is illustrated in Fig. 8. In this case practically the only change is that the modified brake block lllBtakes the place of brake block 12. Block HIBhas an upper end I'll!) projecting through the hole 15 in the casing 24.

This brake block I08 has all the slope of the wedge on one surface N0, the opposite surface H! resting against the supporting flange N2 'of the casing 24 and moving along the same, in other words the block 18 in this instance instead of moving vertically, as in Fig. 5, moves on aslant to cause the surface Hll'to engage the brake surface 63 of the flange 6!.

This construction is simpler in certain respects, for example in that the guide pin H3 mounted in the projection l9 extends parallel to the surface H2, so that the spring-,-'l8 in, the bore H is merely compressed when the brake is applied, and does notalso move laterally as in Fig. 5, However, since the spacing between the brake surface of the wedge and the coacting surface of the conical flange is slight, there is very lit- -tle difference in practical operation of these two forms of brake.

The operation of thegrinder willbe. understood from the structures that have been disclosed. It maybe summarized'briefiy as follows;

The light 35 should be adjusted by bending the flexible conduit 34 to such form that the lamp may be swung to illuminate properly any one of-the four grindingpositions; Once this adjustment has been made, "it will rarely be necessary to bend the conduit 34, thus saving much time and prolonging its life.

The water pct 25, if used, is filled with asuitable coolant, usually water, and inserted in the socket 28' adjacent the grinding Wheel which is to'be used first. r

The work table 12 or it is adjusted to the proper angle to suit the angle to be ground on the tool and the tableis also'adjusted in'orout to provide the proper clearance at the sideof the abrasive wheel, .by manipulating the. star wheel 23 and the nuts 9|.

The work guiding gage 45 will of course also be adjusted to a suitable angle, if a compound angle is to be produced on the tool, asisoften the case. When the upright flange 56 of the gage is inclined at an angle to the guide bar 46, materially smaller than a right angle, the end of the flange 56 will be spaced too far from thegrinding wheel to provide suflicientsupport for the tool at the grinding location, and in such cases the auxiliary tool guide 51 may be used, as already described, to provide better support for'the tip of the tool being ground.

Of course what has been said concerning either work table applies also to the remaining one, inasmuch as work tables f2 and 13 are substantially duplicates of one another. When the rough grinding has been finished at one'of the-wheels, the tool may then be transferred to the work table adjacent the other wheel, the water pct '25 also being shifted to cooperate with the second grinding wheel, and the light 35 likewise being shifted 'to illuminate the new grinding location.

The motor will 'be started and s-topped'and/cr reversed as needed by the switch 8. reversal of the motor is necessary or desirable in order to facilitate grinding certain surfaces of the tool, time may be saved by using the brakes to prevent the wheels from spinning-a longtime afterthe power has been shut off, so that the motor may be reversed without undue loss of time in waiting for the rotation in the first direction to stop.

The water and waste material produced by the grinding will collect in the pan or pans l5, from which it'may be discharged by removing the pipe plug 88, unless it is desired to clean the pans more thoroughly, in which case the entire pans as well as the tables carried thereby may be removed by loosening the nuts 91 and merely sliding out the entire assemblies whereupon they may be flushed with. clean water to remove all sludge and sediment. I

The water pot may likewise be removed bodily for cleaning whenever desired by merely lifting it out, and the ease with which the drip pans I 5 and the water pct 25 may. be removed In case 7 and replaced tends to cause. the operative to keep these devices clean and free from sludge and rust, which 'isfa great advantage over, the

. customary devices of thisv kind whichcanfbe removed only with some difficulty, andqconse The invention thereforeis not to be considcred as limited to the specific embodiment disclosed, but its scope isde'fined' solely "in the claims.

' I claim: r I i '1. A grinder comprising a frame, a shaft carried by said frame, said shaft carrying a flange, and means for rotating. said shaft, an abrasive wheel carried by the flangc,.said fiangehaving a conical surface, a brake shoe mounted in the frame adjacent said flange,'and movable-in a direction toward and away from the axis/ofthe shaft, said shoehaving a wedge-shape whereby it maybe forced against the conical-surface of the flange by moving it radially inward.

2. A grinder comprisinga frame, a shaftcarx ried by. said frame; said shaft carrying affiange, and. means for rotating said shaft, an abrasive wheel carried *by the flange, said flange 'havinga conicalsurface, and a wedge-shaped brakje shoe mounted in the frame adjacent said fiange and manually movable in a direction at an. angle to the axis. of the shaft, said frame having. a" guide for said shoe along whichitmay move, whereby it may be forced againstqthe conical surface of' the flange by movinglit radially inward,

3. A: grinder comprising a frame, a shaft carried by said frame, sa'idshaft carrying a flange, and means for rotating said shaft, anabrasive wheel carried by the flange, said flange having a conical surface, a wedge-shaped brake shoe mounted in the frame adjacent said flange, and manually movable ina direction towardand away from the axis of the shaft, said frame having a guide for said shoe along which it may move, whereby it. may be forced against the conical surface of the flange by movingitinwardly, and resilient means opposing. inward movement of the shoe, and tending to restore it to its initial position when the manual pressure'is discon-' tinued. i

4. A grinder comprising an abrasive wheel-and means for actuating it, a sludge pan beneaththe' wheeL'said' pan having a slotted portion rising above the maximum liquid level of the pan, the

base of sai'dfslotted portion forming: a part of bottom of said pan and disposed belowthe liquid level therein, the'grinder having a surface fitting against the top of said slottedrportion. of

clogged, that ts .essentia t part of the bottom of said pan and disposed below the liquid level therein, the grinder having asurface slidably fitting against'the top of said slotted portion of the pan, means slidably inter connecting said grinder and said slotted portion to constrain the pan to move in a direction parallel to the axis of the wheel, and securing means passing through a portion of the grinder and seated within'said slotted portion, for Securing the pan to the grinder, said securing means comprising a threaded element bearing against the bottomof the pan, and a work table supported on said pan above the liquid level.

6. A grinder comprising an abrasive wheel and 7 means for actuating it, a pan beneath the wheel,

said pan having an elevated portion rising above the maximum liquid level of the pan, the grinder adjacent said wheels and a downwardly directed post on said water pot, said sockets being of similar size and shape and adapted to interchangeably receive said post; a pair of pans for catching water draining from said wheels; means for securing said pans'tosaid frames; and a work table mounted on each of said pans adjacent said wheels.

11. A motor end frame for a grinder, having a cylindrical portion adapted to fit against the stahaving a surfacefitting against the top of said elevated portion of the pan, means for securing the pan to the grinder, said pan having a hearing rising from its bottom, a work table, and a trunnion secured to the underside of said. table and mounted for pivotal movement in said bear-y ing, the height of said bearing being suiiicient to maintain all parts of the trunnion above the maximum liquid level in the pan.

'7. A grinder comprising an abrasive wheel and means for actuating it, a removable sludge pan beneath the wheel, said pan having a slotted portion rising above the maximum liquid level of'the pan, the grinder having a surface slidably fitting against the top of said slotted portion of the pan,

securing means passing through a portion of the grinderand seated within said slotted portion, for securing the pan to the grinder, a work table, trunnions secured to the underside of said table, bearings for said trunnions, said bearings rising from the pan to a height sufficient to maintain the trunnions' above said maximum liquid level, and screw threaded means coacting with said bearings and trunnions, to secure them in any desired relative adjustment.

8. A water pot for a grinder having a frustoconical lug extending downwardly therefrom and adapted to seat in a correspondingly shaped, socket in thegrinder to maintain the water pot frictionally in position, while facilitating its removal at will, said lug and socket having a comparatively small degree of taper, and adapted to be brought into intimate engagement, whereby the Weight of said pot will establish a sufficiently strong frictional connection between said tapered surfaces to maintain said pot in fixed angular position on said grinder.

9. In a grinding apparatus, a grinder structure; a shaft mounted for rotation in said grinder structure; abrasive wheels mounted on the opposite ends of said shaft; means for rotating said shaft, each wheel having two grinding stations, one each side of the vertical plane of said shaft, said four grinding stations being substantially equidistant from the axis of the grinder; and illuminating means, comprisim a lamp and'an ,arm' carrying said lamp; means supporting said arm for rocking movement about a substantially vertical axis located closely adjacentthe vertical plane of said shaft and disposed substantially intermediate saidwheelsand the grinding stations thereof, whereby said lamp may be horizontally swung into any of said grinding stations at will.=

10. Av grinder comprising a motor havin a tionary motor field structure,;said end frame carrying a shaft bearing, Said end frame also having an upper arcuate portion constituting a Wheel guard and a lower flat surface constituting a clamping surfacefor a sludge pan, a brake shoe slidably mounted in said frame for movement toward and away from the axis of said shaft for causing said brake shoe to undergo a com- 'bined axial and radial movement when it is moved inwardly. I 1

12. In a grinding apparatus having a wheel rotatable about a horizontal axis and journalled in a grinder frame, said grinder frame having an axially directed flange located below said wheel and providing. a substantially fiat, downwardly facing clamping surface; a coolant receiving pan having a raised marginal edge and aboss disposed within the raised edge and terminating above the level of the raised edgein an upwardly facing clampingsurface; means for securing said pan to said flange, with said clamping faces in fric-,

tional engagement, said means being adjustable so as to allow said pan to be moved horizontally relatively to said flange, in a direction parallel to the axis of said wheel; and a'work table supported on said' pan within the marginal edge thereof, in cooperative relationship to said wheel and adapted to be bodily adjusted toward and away from said wheel when said pan is adjusted parallel to the axis.

13. The grinding apparatus defined in claim 12, wherein said pan is provided with a pair of raised portions disposed either side of said boss, and each raised portion has an arcuate, upwardly facing seat disposed above the level of the raised marginal edges of said pan, and said table has mating arcuate portions supported on said seats,

and means are provided for detachably securing said table to said pan, with said arcuate seats and v tending slots in said pan, said slots opening onto "the upwardly facing clamping surface of said boss above the coolant level, thereby precluding,

leakage of coolant from said pan;

CHRISTY A. WIKEN.

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