US2434679A - Method and apparatus for grinding - Google Patents

Description

Jan. 20,- 1948. H. W.'W AGNER Er AL METHOD AND APPARATUS FOR GRINDING Filed May 15, 1945 I 5 Sheecs$heet 2 HERBERT WAVAqumi GUSTAV J. WICKSTRDM Jan; 20, 1948. H. w. WAGNER El AL METHOD AND APPARATUS FOR GRINDING Filed May 15, 1945 5 Sheets-Sheet 3 gnaw tom.

m mx Wm d T RV F mu HG.

Jan. 20, 194s. H. w. WAGNER Er AL 2.434579 METHOD AND APPARATUS FOR GRINDINQ Filed May 15, 1945 5 Sheets-Sheet 4 SEPARATOR 3mm HERBERT W WA NgR Bis. w G usTAv d. VICKSTRDIF e4 1948. I H. w. WAGNER ET AL 2,434,579

METHOD AND APPARATUS FOR GRINDING Filed May 15, 1945 5 SIieets-Sheet 5 Z i I g ADJ ITHERMORESPONSIVE ADJU$TABLE Conn RoL Fan For: VALVE l I l I I I I I I I I I I I I I l I I I I I I :jI-vuwwbom 56 HERBERT W. WAGNER l I G. l 4 GIUSTAV J. Wxcxsmou I/I/JMJTW 4 Patented Jan. 20, 1948 UNITED STATES PATENT 7 orrics "iMETiiOD APPAR TUS ,FOR. GRINDING Herbert w. gn and --Gusta.v J.- Widks'ti-om,

Worcester, Mass, assignors toNor-ton- Com pany, W orcester Mass., a corporation of ,.Massachusetts' Application May 115, 1945, serisi-ivo.-59a,s14

This invention relates to grinding, and more particularly to a methodand apparatus for making it possible for agiventgrinding wheel toperform materially heavier grinding ;duty with materially increased length of life of thewheel.

As conducive to a clearer understanding .of certain objects and features of this invention, it might at this point be noted that therate, cost and eificiency of grinding ofworkpiecesfsuch as parts made of steel, alloys, and various other:

' metals, both hard and soft,'are limited ,aiid 'held down, in heretofore known methods ,aridlapparatus, by anumber of factors,' suchas depthofciit which thegrinding' wheel can take, ratof relative feed or traverse between the work and the grind ing wheel, wheel wear, character onfinisn'produced, frequency of wheel truirrg (whichfalso greatly affects the life of the wheel) ternperatiires produced at the 'grindin'g'line and also inthe work, and the like; this is true even if. tlie'.best

pieces to beoperated upon. This is true :for various types of grinding, such as surface grinding, internal and external grinding or round or cylindrical surfaces, etc., etc., and these limitations become still more restrictive where the grinding wheel is called upon to function bywway of. both surfaces of its corner or corners,as, for example, when the wheeLas in crankshaft grindinghas to function by way of its outer cylindrical surface and its two side faces as well in such cases, the burden at the corner or corners of the .wheel is multiplied, thepcorner or corners break down or wear too rapidly if the grinding burden is too heavy, and theshortening of wheel life by too fre- -quent-trueing of the cylindrical face to restore the corners'becomes prohibitive. Wehave discovered a method and apparatus, applicable to; suchatypes of grindingoperations or their corresponding grinding machines as above mentioned,- whereby suchlimitations :as those-above mentioned are substantially lifted: and whereby such grinding 4:5

.of grinding-maclnnes and applicablein generalto machines may beoperated and their grinding oper'ations performed at a level of rate and efiiciency of grinding heretofore unachieved and heretofore impossible of achievement by known grinding eth s .o appa a u Other objects of this invention are to provide a g i ng; me ho a pp a us of the S stmentioned nature that can be efficiently and ecom e l rutmi n asti e' id a will b re ily and inexpensively adaptable to known types gi inding m a chines, particularly to those types where relative traverse movement between the i -work and-g rinding wheel to effect progression of f'fof iilci'easl'ilfgfthe life' or a grinding wheel. Anot er object'is to provide a methodan'd apparatus for grinding in which the grinding wheel may be the ciiit takesplace, orrelative traverse in successive strokes accompanied by successive Wheel feedtake ,place, or the like. Another object provide amethod and apparatus for increasing thecapa'city of a given grinding wheel. Another object-is. to provide a method and apparatus made cuneiform at greater than heretofore-considered 'normal' capacity, at better whe'l life, and at the 'same or materially lessened power input.

lAndtherobject istoj provide a; method and apparatus forcprctectingthe grinding Wheel and the workpiece; under conditions of increased duty of the grinding wheel, against loading of the wheel and detrimental breakdown of the wheel and against temperature conditions in both the wheel and the work as are detrimental to either or both.

' widely varying practical requirements and kinds or types of grinding operations. Another object is to provide an easily-controlled flexibility or variability of action and application of a plurality of liquid coolants or grinding liquids to the grinding wheel and workpiece to meet different conditions met with in the grinding of certain "kinds or shapes of workpieces and also to' meet varying conditions-imposed by different kinds-or "shapes-of workpiecesor.-different.grinding operagtions. Another obiectiszing'eneral-tozachievejsuperior grinding and longer wheel life than has heretofore been possible. 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, arrangements of parts and in the several steps and relation and order of each of the same to one or more of the others thereof, all as will be il1ustratively described herein, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which are shown several illustrative embodiments and applications of the mechanical features of our invention,

Figure 1 is a schematic or diagrammatic representation of an apparatus for practicing our invention;

Figure 2 is a fragmentary diagrammatic front elevation as it would be seen from the left in Figure 1, illustrating the application of our invention to one known form or type of grinding machine;

Figure 3 is a fragmentary schematic view or representation, as it would be seen from above in Figure 1, illustrating another type or kind of grinding operation to which our invention is applicable;

Figure 4 is a side elevation on an enlarged scale showing a preferred form of apparatus or device employed in carrying out our invention and indicating diagrammatically certain actions that it achieves;

Figure 5 is an elevation as seen from the right in Figure 4, certain parts being omitted;

Figure 6 is a diagrammatic representation to indicate certain actions that take place on the surface of the grinding wheel at and adiacent to the grinding line;

Figure '1 is a fragmentary vertical sectional view on an enlarged scale as seen along the line 1-4 of Figure 5;

Figure 8 is a view like that of Figure 6 representing diagrammatically certain actions resulting from certain adjustments;

Figure 9 is a fragmentary representation in diagrammatic perspective indicating certain actions at the corner of a grinding wheel;

Figure 10 is a fragmentary schematic view or representation, as seen from above, illustrating a corner grinding operation;

Figure 11 is a diagrammatic or schematic representation in front elevation illustrating one form of embodiment of our invention in surface grinding;

Figure 12 is an end elevation as seen from the right in Figure 11, certain parts being omitted;

Figure 13 is a view like that of Figure 11 illustrating a possible modified control; and

Figure 14 is a diagrammatic representation illustrating certain separating and treatment apparatus of our invention.

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

As above indicated, the method and apparatus of our invention are applicable generally to grinding operations and grinding apparatus; our invention is probably best illustrated with respect to such grinding machine in which a grinding wheel performs a grinding operation upon a round or cylindrical surface of a metal workpiece which is supported and rotated during the grinding operation, suitable means being provided for efiecting relative movement between the workthe grinding wheel in a direction transverse to the axis of the rotating workpiece a when one or both of the side faces of the grinding wheel are to grind portions of the workpiece, with or without having the peripheral face of the wheel performing a grinding operation, and the like, and to achieve greater simplicity of description and to avoid limitation by implication, any such apparatus, chosen for illustration of the applicability of our invention, is indicated in the drawings by a simple representation of a grinding wheel G and a workpiece W which may be supported and rotated by any suitable means not shown and traverse feed and other movements, relative or otherwise, are simply indicated by appropriate arrows. Any well known form of grinding machine may be employed and for greater facility of description it may be assumed, but not by way of limitation, that the workpiece is mounted on centers and driven at suitable speed and in suitable direction.

Supported in any suitable way, from any suitable part of the apparatus-conveniently from the heavy g ard ID that covers over or encloses most of the grinding wheel G--is a device generally indicated by the reference character ll constructed and adapted to supply a plurality of liquids for coaction with the grinding wheel G and the workpiece W, and a preferred and illustrative construction of which is shown in larger scale in Figures 4 and 5, to which reference may now be made.

The device ll comprises a nozzle I! or other suitable device for discharging and generally directing a liquid preferably in large volume and preferably at low pressure; it is to handle a liquid, the principal or primary characteristic of which is that it have good capacity for abstracting heat and, hence, we refer to it as a coolant liquid. The nozzle (2 we mayrterm a coolant liquid nozzle or a low-pressure nozzle. It is conveniently made of steel piping of suitable diameter and length, being provided at its upper end with suitable means for connecting it into a liquid circulating or liquid pumping system, and conveniently the upper end may be threaded, as at iii, to receive a pipe coupling l4 (Figure 1) by which it may be connected to other conduits or pipes diagrammatically indicated at l5.

Its lower end curves inwardly from the vertical axis of the part [2 and, hence, toward the grinding wheel G, as viewed in Figures 1 and 4, and, where made up of round tubing, its lower end preferably also is shaped-as by flaring it out laterally to both sides of its vertical axis, as viewed in Figure 5, and by progressively narrowing it in internal and external dimensions, as viewed in Figure 4to provide a discharge mouth M that is of a length commensurate with the width of the peripheral face P of the grinding wheel G and, hence, is of a length commensurate with the length of the grinding line L along which the work is contacted by the wheel face P. The mouth M may thus be of generally rectangular area or shape, and may have uniform transverse dimension or width, and thus it is capable of discharging coolant liquid in large volume, prefer- 5 ab'ly the ananner hereinafter described, at 'not onlyauni'form'rate per unit area of the'mouth' M, but also at substantially uniform volume per'unit "length of the mouth M.

In so shaping the mouth end *of the tube l2, we-are enabled also to provide, upon that wall =of the mouth nearest the grinding wheel G, a flat or-planeportion I! along or by which is'suitany aligned or related to the mouth M'o'f the mozzle it-suitable discharge means for a liquid, the piincip'al -or primary characteristic of which is to 'proinote the action of cutting or-grin'dingiat the 'z'grinding line and throughout the 'relatively -'small area or region where such action takes iplac'e'; this liquid we sometimes term herein the active liquid or the grinding liquid, and, since, in =a preferred embodiment of the invention, we a'pply 'it at relatively high pressure and in low volume,=the'discharge means for it--which, illustratively, 'comprises one or more nozzleswe sometimes term herein as a high-pressure'nozzle or no'zzles. -If more than one nozzle is employed, ':they:=may be aligned alongthe flat portion ll of nozzledevicel2, and an illustrative number for an illustrative width of .grinding wheel face is three-best-indicated in Figure 5 by the reference characters 19, :20, and 2|. For example, where the m'outh M 'of the coolant-liquid nozzle has a 'length on "the'order of three inches for a width of grinding wheel face P of" about three inches,

the high-pressure or active-liquid nozzles I9, 20, 'and-2I have-discharge-orifices which are preferably andmost conveniently circular in'shape and of-a-diameter on the order of one-sixteenth of an--inch,'and their distribution along the length of the mouth M is preferably substantially uniform and an illustrative distribution may be like that indicated in Figure 5.

The nozzles 19, 20, and2l are arranged to be connected-to a supply system, preferably a'pressure circulating or pumping system later described-and the piping or conduit of which is indi- -cated-at'23in Figure 1, and preferably the supply of liquid'and the action of each'nozzle are-controllable and regulatable for reasons later described.

A convenient, illustrative, and preferred arrangement for coupling the individual nozzles to the-conduit 23 may be like that shown in Figures 4, 5,= and 7. Thus,'the flat wall I! (Figure 5) of tlie low=pressure nozzle l2 may be slotted, as by millinggat lts lower end as'indlcated at 25, 26 and '2'lso as'toreceive therein blocks '28, '29 and 60, respectively, preferably shaped, constructed "and mounted in the manner-illustrated in enlarged scale in Figure '7 with respect to the block member 28. Thus its front face 28 is preferably aligned-with the front face of the fiat wall I! as it -isfitted into its slot 25, and it is preferably "welded-or brazed or-otherwise secured in position to the wall-p'ortion 11. It has an upper face 28 which extends substantially at right angles to -the front-face'28 and hence to the plane of the -flat front wall i1 and contains an angular chan- -nel=*3l fo'rmed as by drilling from the top face 28* -and1also' by drilling from the inclined portion 28 of the front face. The outwardly exposed end of channel GI is preferably constructed to detachably and adjustably mount therein the high pressure nozzle 19 and preferably the latter is con- -structed to have a threaded shank I9 receivable -into the downwardly and outwardly exposed end ofthecchannel 3| which is threaded as indicated at' 3l; through the nozzle'element l 9 is a passage 33 conveniently formed asbydrillingand serving also an or-ifice. Preferably, orifice channel :38 extends :at an angle to the axis of the threaded Eshank 1Y9, rillustratively an angle on the :order "of 252, so that, *by changing the rotary position as of'the-nozzle element 19 about the just-mentioned .axis, the point at which the emerging stream of liquid impinges upon the face P of the grinding wheel may beshifted both horizontally and ver- 'tically,'that is,ito the right or left as viewed in 5.11) Figure 5"and .u or down as viewed in Figure 4.

'To'simplify the control of the setting of the :orifice element l9, the fit of the threaded shank 'lil inthe threaded channel part 3 I is preferably :made relatively-tight and hence self-locking or self-holding against unintentional rotary movementand the shank =l9 'is provided with an externallarger-diameter portion [9 which maybe given an external hexagonal or other suitable shape-to permit application thereto of a wrench or maybe slotted as at l9 to permit engagement of 'atool like a screw driver. Thus ease of rotary adjustment and dependable maintenance .of :the desired setting are achieved.

'The other end of channel 3| which, in the illus- 125 trated preferred structure is exposed internally of the tube [2, is constructed to have a relatively 'small tube or pipe 32 connected to it, conveniently .as by'providing that end of the channel 3| as with a" socket 3i and to receive the tube 32, a sealed f'co'nnectionbeing eflfected as by soldering or sweating the'twoiparts together.

"Where more than one high pressure nozzle ele- -m'ent is employed, and as will now be clear, they are similarly constructed and mounted as just :3 described 'withrespect to the orifice-nozzle element [9, and it will be'seen that the supporting block, such as the block member 28, and the nozzle element carried by it, such as member l9 of Figure 7,may be constructed in quantity as 40 units and may be assembled to low pressure nozzle members like the element l2 in any desired-spacings and in any desired number. "In Figures 4.5 and 7,-the connecting tubular conduits of the additional nozzle units 20--'29-and 2l- 30 are indicated at 34 and 35, respectively,

the-three relatively small tubes extending upwar'dly within the tube element 12 to a control distributor generally indicated by the reference character -36 and being relatively small, being preferably made of a metal like copper or bronze, they-are'also mechanicall encased and housed 'by the'relatively large heavy and strong tube 'memberf2 and thus protected against mechanical injury, distortion or the like. In cross-section .55 they are relatively small as compared to the cross-sectional interior of the low pressure nozzle member l2 and the capacity of the latter is not detrimentally aifected by their presence nor is the discharge flow of liquid from the mouth M of the low pressure nozzle member l2 materially afi'ected as to its desired rate of flow and action, by the presence at or in the mouth M of the nozzle-mounting blocks 28, 29 and 30.

The control distributor 36, referring now to 5 Figures 4 and 5, comprises ablock 31 of suitable metal providedwith a main distributing channel '38 formed as by drilling a hole of substantial diameter from one end face 31 toward-the opposite end face 31', but falling short of the latter, the openend of the channel 33 being threaded as at i8 to provide for the threaded connection thereto of the high pressure conduit 23 above mentioned.

We then arrange'for' the connection to'the distributing channel 38 or =as 'many --pipes "or tubes as there are high pressure nozzles, illustratively the three tubes 32, 34 and 35, but preferably in a manner to provide for the individual control of the volume and pressure of flow of liquid to each high pressure nozzle. Thus we may provide, as by drilling from the side face 31, three channels 31, 31 and 31 which intersect the distributing channel 38 at their inner ends and in their outer ends receive and have sweat ed or soldered thereto the tubes 32, 34 and 35 which pass through suitably large holes H provided in the adjacent wall of the nozzle tube 12.

.In assembly, the nozzle-carrying blocks, such as blocks 28, 29 and 30 of Figure 5, are joined to the lower ends of their respective tubes after the latter have been connected to the channels 31 31 and 31 of the block 31, whence the nozzle-blockcarrying ends of the tubes are snaked through the holes H which are large enough for that purpose and snaked downwardly within the nozzle tube 12, thus bringing the nozzle-carrying blocks into position to be received within the slots 25, 26 and 21, respectively, in the wall portion l1 and thus also bringing the face 31 of the block 31 of the distributor 36 into alignment with the outer face of the tube element 12 to which it is secured as by welding, indicated at 40, and to the curvature of which the face 31 is suitably conformed.

-Thereby also the holes H are closed off, and it will be seen that commingling of the liquids supplied to the mouth M of the low pressure nozzle and to the orifice channels 33 of the high pressure nozzles does not take place.

Suitable controllable valve means are provided, preferably one for each high pressure nozzle circuit and such control means we preferably assemble to or build into the above-described block 31, conveniently relating each to one of the channels 31 31 and 31. Such means may comprise valve structures generally indicated by the reference characters M, 42 and 43 and preferably of identical construction. Thus, each may comprise a needle valve stem 44, preferably threaded and conveniently it is of the same diameter throughout its length and preferably slightly larger in diameter than the diameter of the drilled channels 31, 31 and 3'! and they are threaded into holes 31 31 and 31 which respectively intersect the channels 31 31 and 31, being formed as by drilling from the face 31 of the block 31 toward the opposite face to a depth sufiicient to intersect the tube-connecting channels. Each valve member 44 may be provided with a handle or thumb grip 45 to facilitate setting by hand if desired, their threaded fit into the just-mentioned threaded holes is preferably relatively tight so as to be leakproof and self-locking, but a lock nut 46 may be provided for each and, if desired, a gasket of suitable material that is compressible and radially expandable under the compression of the lock nut may be employed to insure against leakage, particularly where the pressures dealt with are very high, or any other suitable form of stufling box or packing gland may be employed.

Accordingly, the amount of liquid flowing to each high pressure nozzle and hence also the pressure effective upon the orifice channel of each nozzle may be set by adjustably positioning the valve structures M, 42 and 43 to any such respective positions as may be desired between complete cut-off of the channels 31 31 and 31, as when the valve stems 44 are threaded inwardly to completely obstruct these channels, to maximum now as when the valve stems are threaded outwardly to positions in which they do not "materially obstruct the flow in the channels or materially reduce the cross-section thereof at the valving point therein.

In the high pressure pipe line 23, which may be provided with suitable valve controls such as the valve 41, we provide suitable means for supplying to the control distributor head 36 liquid under suitably high pressure, and such means may comprise a pump diagrammatically indicated at 48 in Figure 1, the pump being preferably of any suitable high pressure, relatively low volume, type. It may be driven by any suitable means not shown, such as a separate electric motor or from the main drive of the machine by which the grinding wheel G is driven at a suitable grinding surface speed. A wide range of pressure may be selected for the high pressure side of the system, depending upon various factors, such as the composition and action at the grinding line of the liquid to be employed, the character of grinding operation to be performed, and other factors later mentioned. For present purposes, pressures from about 20 pounds per square inch and higher, such as 100 pounds per square inch or over may be considered, and any suitable means may be provided for setting the pressure of the output of the pump 48 at the desired value-such as, for example, a by-pass pressure regulator diagrammatically indicated at 49.

In the pipe line l5, which also may be provided with suitable valve controls such as indicated at 5 1, suitable means are provided to supply the relatively large and high-volume tube nozzle l2 with large volume of liquid at preferably very low pressurea pressure which is preferably only sunlcient to achieve large-volume, low-pressure, and relatively low-velocity flow or movement of liquid out of the very large mouth M. For this purpose a suitable high-volume, low-pressure pump,

diagrammatically indicated at 52, driven in any suitable manner-for example, like the drive of pump 48--may be provided, and for control of the flow out of the mouth M, valve 5| can sufi'ice, for, as later described, variability as to volume or quantity of flow can sufi'ice.

To give illustrative functioning and results of our invention, let it be assumed that the workpiece W is of steel and the grinding wheel G is of a structure, such as ceramatically-bonded, suited or selected for operation upon the particular kind of steel of the workpiece W, and that the grinding wheel G is driven at its best-suited surface speed and the workpiece W is rotated at a correspondingly best-suited surface speed-all as measured or determined by heretofore known criteria or standards. In carrying out a preferred embodiment of our invention, we supply, simultaneously, to the low-pressure discharge nozzle 12 and to the high- pressure nozzles 19, 20, and 2|, respectively, a suitable coolant liquid and a suitable promoting or active liquid,illustratively, water for the former and oil for the latter,utilizing, in the said embodiment, respective pressured therefor like those-above mentioned, substantial commingling of the two being avoided by the arrangement of the respective nozzles relative to the work and grinding wheel and by other actions later described.

As appears better from Figures 4 and '1, the orifice channels 33 in the high-pressure nozzle or nozzles are directed so that the high-velocity and high-pressure streams of oil that they emit impinge, in the preferred arrangement, upon and 9 against tbs grinding heel eera lve urtaca nhe llustration the p ph ral. sur we' at. a. po nt. r po n s; prcter hlniust mew at. n da Yanceo the r ndin l he n le, or 111-. c d nce o he lush-nr ss re-Qi st ms pref: erablr uch; hat. the i s re m make an cute. an l nd ca ed at A mmensew h he rinds; heel urface. wi h the p x at h an le..-

directed generally the direct n s he. r c ion of trav l.- oie opera iv surface. of th ing wheel o st t d differently, the oil: s r m. r streams a t d nt he nsu ar tv termed be we n he. surface the w k be.- .i ground. an the a vancing operat vesu ace the r d n wheel. u Qfis s a o ke. the grinding wheel, surface at. a. suitable. point displac d m t e. r d ng line n F u e h s r am fr m hiehm e u ozr ale [9 is indicated at and the point where it. strikes the grinding wheel surface P is indicated at, I. The distance from point I to the grinding line L is variable,- according to various factors, such; as thepressuro at, which the oil is supplied to, the high-pressure nozzle, and. for purposes of illustration it may be on the order of of an inch-or /gil'l-Qh r; so, The a le A is. also variable and the desired effect, later described, may be achieved ith a W de range of change of angle A; it pr f r b y an acuteangle with it apex headed in the direction of travel of the operative s rf ce of the r nd n w s l. in order mor fectively to spread over or cover the. moving. ri d n whee su fa e. between t point. I an h r ding ine Mina-substant a l s r t 1. that act on b in aided y ra ia ora ne ud n the direction r mo emen th gri n w eel suriac B and. th h h el i o r l. of the. oil in the impinging, stream or streams. For the stream in Figur {1, thisfilm of oil. of subs n ial. hick s i di a ed t. a d it r ch s r Point o e ndi l L. and inli'igure 6,1 indicatedat S! the cross-sec: tion of stream S just before it strikesthe grindns whee su face B at he min w ic w l th r wn o flr ge me r p in d 1 f im ns n but an area t l a t as l r as t e ro s q ic oi the t e m; nd uall sub tantially larger because of the. spreading ac-. tion that takes place as it actually strikes the grinding wheel surface.

aessere w e es. in. th lus ra ion such as to r u re three high-pressure streams or jets, they are; appr at y st but d so. ha he d w wa y n twardly tanni r diver ng y r F F dv F ee 3 s re '6'). ov r a pr r b y well,

n a nce. o the. r nd n ine 1., th s to ma r hat he. nt re ace o t e. r d n wh as t mor s a h h v lo it ow rd t e n n n sco ercd w tba s stan al th cknes of l uid The grinding wheel surface P, however, is movingdow-nwardly, as viewed in Figures 1, 2, 4 and 6, at high velocity, illustratively at, an appropriate grinding speed which may be on. the order of 6,000 surface feet per minute, and as a result, aided by the angle A where the latter is an acute angle, the oil. from the impinging stream S is carried intact as a film of substantial thickness downwardly by the grinding wheel surface toward the grinding line L and in actual action it. fans out orspreads or diverges downwardly and crosswise of the wheel face P, to both sides of the point I of incidence. This spread, indicated in Figure 6 by the reference character R iscontrollable and variable, as is, later described and illustratively may be on the order of about or A of an inch Were the grinding wheel surface 1? to be of a width o a ou 7.1. of an n h. it wi l h s be seen, a single highsvelocity high-pressure stream or jet of liquid, such as. the stream S of Figure 6, if directed at the midpoint of the wheel surface, would suflice to give a spread B suflicient to supply the rin in iese su iaca. t a d n a an o th rinding; nen with a unitar 9 intact ava .1 5s were? liqu d Wher tbs hee .P

Emer i from the. m u h M of the a evolume, low-pressure nozzle I2 is a slow-.moving u s ntia lrunbrols n. tre m r o n C of water; its head is; small or slight, just, sufficient to maintain a, steady copious flow, and in comparison to. the energy; in the high-pressure jets, the. stream or column C, is of very small or virtuallyimmaterial energy content, and in relation to the h h velocity of mo ement of he h pressure streams S S4 and S with their diverging and highevelocityl layers or films F F and F (see. Figure 6,) we, by the just-described relationships, make sure. that the stream C interferes practically not, at. all with the above-described conformation of the high-velocity streams or jets and their high-velocity films or layers. The latter thus remain intact and substantially undisturbed and. substantially free from material disruption by the slow-moving, but copious stream C, and thus the liquid substance, illustratively oil as above mentioned, that is supplied to, the grinding machine through the high-pressure noz: z le or nozzles is with certainty brought to the grinding line. hwhere its qualities and characters istics, later described, coact with the grain and bond of the grinding wheel. and the material of the workpiece W to. achieve grinding actions later described. liquid substance, peculiarly adapted for facilitating high rate ofcutting bythe abrasive grains of the wheel is backed up (see Figure 4. by the largeevolume, slow-moving liquid column C, which is preferably of water. a good heat-absorber, and which can fill the. angle between the surface of the work piece W and the outer faces of the fanned-.eout layers F F and FF, and thus the liquid of the latter is not only fed to the grinding line at a low temperature (room temperature, for example) but also is prevented during the. actual grinding at the grinding line L with its accompanying production of heat from being so raised in temperature as to diminish or vitiate its coaction with the grinding wheel. The liquid from the stream C spills to the right and left (see Figure 2) from the trough-like space above the grinding line L, spreads onto the grinding wheel below the grinding line L to withdraw heat from it, and also, from this lateral spilling-over, spreads onto the work piece W to withdraw heat from the latter, and if desired and according to the dimensions and setting of the parts, some of it can also be made to spill over the top of the work piece W as indicated at C Thus the temperature of both grinding wheel and work piece can be dependably held down to a value, in spite of any increase in energy that may be manifested at the grinding line L in the form of heat because of the resultant increased ca.- pacity of the grinding wheel, at which the grinding liquid in the high-pressure streams and films or layers is best adapted to function and thus also burning with resultant deterioration, and evaporation of the grinding liquid and resultant waste thereof can be avoided; thus also the creation of obnox us il ness ca b a o d d n e ne O exhau co nates n ed not eseeip e ed, and

ll grindingoperations can be made less hazardous to health.

It will be noted, by reference to Figure 4 for example, that, even if the grinding wheel itself becomes materially raised in temperature, such increased temperature is prevented from having material effect upon the grinding liquid supplied to its surface from the high-pressure nozzle or nozzles because that liquid, being backed up by the large-volume column or stream C of heatabstracting liquid, is by the latter prevented from itself being raised in temperature, and the liquid of the column C, being in thermal contact with the film or layers F, F and F of the grinding liquid, isthus capable also of withdrawing heat from the grinding wheel itself in advance of the grinding l ne L, thus further to resist undesired pro-heating of the high-pressure, high-velocity liquid from the grinding wheel itself.

It is probable that small or minute quantities of liquid from the column C become commingled at the grinding line with the liquid from the highpressure nozzles, but such action is in substantial measure controllable and according to the nature of the work it can be beneficial to the actual grinding operation. Where, for example, it' is desirable to avoid or minimize such commingiing at the grinding line L, the pressure at which the liquid is supplied to the high-pressure nozzles may be increased as by correspondingly setting the pressure regulator 49, and thus the velocity of the streams S, S and S may be made so materially greater than the velocity of the grinding wheel surface P that the fanned-out layers F, F and F are thicker and move at increased velocity, thus more efiectively to nose out the liquid from thecolumn C against reaching the grinding line L in substantial quantity. The valve structures 4|, 42 and 43 in the control distributors 35 may also be set or adjusted for this purpose.

Analogous effects may also be achieved by so adjusting the compound nozzle structure U or by setting the individual nozzle elements I9, 20 and 2|, or both, to lessen the distance from the point of incidence I (see Figure 4) to the grinding line L, thus to diminish the chance of the liquid from the stream C from commingling with outer portions of the layers F F and F Also, the active fluid emerging from the nozzle elements l9, 2|] and 2| may by such adjustment be made to impinge directly into the apex of the angle between the wheel face and the work surface, and still form an effective barrier against material entry of the coolant liquid into the region of grinding contact. According to circumstances also, the volume of flow of liquid in column C may be lessened as by the valve 5| (Figure l) to better suit it to the barrier action of the active grinding liquid.

The pressure of the grinding liquid supplied to the grinding operation may be varied and even materially cut down or its direction of flow or shape of stream altered so long as it has the effect of a barrier to prevent material commingling with the liquid in stream C.

In carrying out our invention, because of the protective action of the high-volume, low-pressure liquid supplied through nozzle |2 upon the highpressure, low-volume grinding liquid supplied through the nozzles, it is possible to use, over and over again, the liquids employed; if the low-pressure liquid employed is water, it may, of course, be freely replenished from any suitable source of supply, and in any case it may also be re-used,-' whatever form or composition it 1 takes.

we -prefer to catch the coolant and active liquids,

after they have performed their functions, in any suitable sum or settling tank, generally indicated in Figure 1 at 54, in which some settling may be passed, as by a conduit 55, to. any suit-- able form of separating apparatus or system diagrammatically and generally indicated as a unit in Figure 1 by the reference character 56. In

the separator 56 the solid particles are removed or separated out, and the two liquids separated from each other, and, as so separated, the highvolume, low-pressure liquid may be passed, as by the pipe 51, to the intake side of the pump 52, and the low-volume, high-pressure liquid passed, as by pipe 58, to the intake side of the pump 48.

In so far as certain features of our invention are concerned, the separator 56 may be of any suitable construction appropriate for the bandling and suitable separation of the particular liquids employed; thus, it may effect separation by centrifugal action or, by way of further example, by settling out one of the liquids below the other because of their different specific gravities. However, according to certain other features of our invention, we are enabled to achieve certain advantages and beneficial 'coactions by giving the separator system 56 a form later de scribed in detail.

In Figure 2 is shown diagrammatically the apparatus of our invention applied to a grinding apparatus in which the workpiece W is to have its external cylindrical surface ground throughout its axial extent, the apparatus being arranged as in any known manner to effect a relative traverse in axial direction between the work and the grinding wheel, thus to progress a selective depth of cut lengthwise of and throughout the axial extent of the workpiece W the set-up of Figure 2 is thereby intended to illustrate or typify a grinding operation in which the grinding wheel operates by one of its available operative surfaces, illustratively the peripheral surface P. In such a set-up, the relative pressures of the two liquids, the settings of the nozzle elements either as a whole or individually as to the high-pressure nozzle elements I9, 2|] and 2| may be as above described in connection particularly with Figures 4 and 6, the overlapping or joined fanned-out grinding liquid layers F F and F being controlled to insure coverage of the grinding wheel surface P along the length of the grinding line L and also in advance thereof, it being pointed out that the relative traverse between the grinding wheel and the workpiece W has substantially no material detrimental effect, such as detrimental distortion, upon the film or layer of the one grinding liquid that is laid against and carried by the grinding wheel surface or upon the action and functioning of the stream or column C of the other liquid. Certain illustrative grinding performance figures, with a setup like that just described in connection with Figure 2, are later hereinafter set forth.

As earlier above indicated, there are, however,

grinding operations in which the grinding wheel is called upon to operate by way of one or more operative surfaces in addition to its peripheral surface, such as operations where the two faces forming a corner of the wheel operate, thus imposing peculiarly severe conditions ofi performance upon-the wheel structure, and to illustrate diagrammatically shown a set-up comprising the grinding wheel G and a work piece W in the form of a crankshaft in which the crankpin CP is to be ground to cylindrical form of the right diameter and simultaneously the adjacent side faces GI and 62 are to be ground plane at right angles to the axis of the crankpin CP, such work usually requiring a relatively sharp corner at the respective junctions between the faces 6| and 62 and the cylindrical surface of the crankpin CP. A typical limitation is that, at these corners, a fillet not to exceed a certain radius is permissible, such as a radius of /s4 of an inch. In Figure 3 the fillet is indicated at 63. The apparatus dlagrammatically indicated in Figure 3 is of the kind in which the crankshaft W is mounted in suitable supports (not shown) to rotate about the axis, indicated at 64, of the crankpin CP and in which suitable provision is made to effect relative movement between the grinding wheel G and the crankshaft W to diminish the distance between their respective axes, thus to bring the side faces P and P into action, respectively, upon the work faces BI and 62 and ultimately to bring the peripheral operative surface P into action on the surface of the crankpin CP, the grinding wheel G being trued so that its peripheral surface P is truly cylindrical and so that the side faces P and P are parallel to each other and spaced apart by a distance to grind the faces 6| and 62 not only parallel but also to the required spacing between them.

In such an operation, as the grinding wheel and work piece are brought into coaction, the mechanical burden upon the corners of the wheel is unusually heavy and severe, both during the in-feed, that is, as grinding of the side faces 6| and 62 proceeds, but also and more particularly as the grinding of the crank pin CP proceeds; the faster that one attempts to carry on this type of grinding operation, the more rapidly do the corners of the wheel wear and break down and the more frequently does the wheel have to have its peripheral face P trued off, thus to restore the corners, and thus the life of the wheel is greatly shortened. With our invention, however, we are enabled to achieve increased grinding production and to extend the life of the wheel.

For simplicity it may be assumed that the grinding wheel G of Figure 3 is of the same width of face as was assumed to be the case in Figures 2 and 6 and that, therefore, the same compound nozzle structure ll, embodying illustratively three high-pressure nozzles I9, 20 and 2|, may be employed; the width of the 1aterally flared lower end of the nozzle structure |2 (see Figure 2) can be less than the width of the peripheral face P of the grinding wheel, and, overhanging the latter in the manner shown in Figures 1 and 2, the structure U will be seen not to be in the way of the swing of the crank parts of the crank shaft W as the latter is rotated about its axis 64.

For such a crankshaft grinding operation, and in view of the duty to be performed by the side faces P and l? of the grinding wheel, it is preferred to better insure the supply of high-pressure grinding liquid to the region or regions where the side faces are performing their respective grinding operations, and in such case one or more adjustments or settings may be brought into action, either individually or in coaction.

, For example, and referring to Figure 6, the

14 pressure or rate of flow in the streams S and S emerging from the outermost nozzle elements I9 and 2|, respectively, may be increased as by increasing the opening of the valve structures 4| and 43, respectively (Figures 4 and 5), and such action would have the effect of increasing the fanning-out or divergence of the films or layers F and F and thereby causing more oil or other grinding liquid from the streams S and S to be diverted laterally beyond the planes of the side faces P and P respectively, thus making more grinding liquid available for coaction with the crankshaft faces 6| and 62 (Figure 3) and the respective side faces of the wheel. In making such a setting, therefore, the pressure and veloc ity of jets or streams S and S would be greater than those of stream 8*.

Or, assuming that, as earlier above described with respect to Figure 6, all of the rotationally adjustable orifice elements |9, 2|] and 2|, had initially been set so that their orifice channels 33 are parallel to each other, their downwardly inclined axes (see Figure 7) falling in parallel vertical planes, we may insure the greater supply of grinding liquid to the grinding operation at the side faces by rotationally shifting. the setting of the outermost nozzle elements l9 and 2|, in directions respectively clockwise and counterclockwise as viewed in Figure 5, thus causing the points of incidence of the jets S and S to become displaced more closely to the respective side edges of the grinding wheel face P, somewhat in the manner indicated in Figure 8 which, when compared with Figure 6, shows how, as a result, the axes or general lines of flow of the fanning-out layers F and F are thereby directed or inclined away from each other and respectively toward the faces 62 and 6| just above the line or arc of the peripheral face P of the wheel, thus flowing an ample supply of grinding liquid onto the surface being ground and also onto the side faces P and P of the grinding wheel itself. If, in making such an adjustment, the spread of an intervening stream, such as the spread F of the jet S is insuflicient, the rate of flow or pressure, or both, in the pipe line supplying the intervening nozzle-in this case, nozzle element 2|l-may be increased, as by increasing the opening of the valve structure 42.

Or, of course, both adjustment of pressure and adjustment of angle of incidence of the various high-velocity jets may be effectedto achieve the desired action and distribution. In a grinding operation like that of Figures 3 and 8, the highpressure, high-velocity liquid is again backed up by the high-volume, low-pressure liquid of column C emerging from the mouth M of the nozzle |2, and, because of factors like those above described, commingling does not take place to any detrimental extent, and vastly increased grinding performance with correspondingly increased length of life, due to the greatly improved standing up of the wheel corners, are achieved--with respect to all of which some illustrative performance figures are later hereinafter set forth.

As above pointed out, the high specific heat of water, its ready availability and inexpensiveness, make it a preferred liquid to employ, for the high-volume, low-pressure side of the system. For the active or grinding-promoting liquid usable in the low-volume, high-pressure side of the system, we prefer to employ an oil of which a wide variety and kinds are usable according to our invention. It is preferred that the active or grinding liquid and the coolant liquid be substantial n-inso uble one in t ea iheraand a-.- e fz-ai strationsz t usable. oils .may e set. forthaller them; with respect: towater the. oolant; liquid; me t n 3 th s: preference. Oi s. such; s... mi era mal-.1017; e ta le ls; a be employed,- preferably. treated to embgdy; ine. redients, such. as sulf r: r. ch.1 i e= compoun to. give-:them or to; improve;-;their action. at the ind gl nein-p omotingc tine bath asi rains; ils; or. t s. nature-may be loaded. in known manner with; suitable sulfur compounds on chlcrine. compounds; CIT-1301311581161?! as, for-ex:- mp ei; s lfur: h r d and p ef r bly th y are suitably.- tre e .inkn wnmanne toutil ze an have.embQd edahereinanima or. egetable fa ndrusuallyr a so. sulfu Fo xamp ul u may be reacted with suchzfats anddissolved in amineral oil base,- giving-;what. is very probably a;col;loid-or colloidal solution; from; such a com pounded oil,- maximumcutting or grinding bene-- fits-areachievedebenefits derived not only from they presence of 1 the I fat, but. also from the pres-,. enceof; the sulfur. Mineral. oils, without modification by such additional ingredients as sulfur, fat-,, orchlorine, are usable to-advantage in our-invention; some ranimaLoils and some vegetable; oils,- when;employed in our invention, show less-advantage than-other- --a nimal or vegetable 0ils;,and,- hence-,thein selection as the active liquid in1our-system will,, of; courses be correspondingly influenced,

Most ccnrenientlmiandprei ah rwee oy cene-lied. grind n o lsi; frthef nso ub el';t pe. many orwhicnare-availablebathe-marke nd whicheare;.=esnecia .ly omnounsi d1forrer dine. perations-a; Some of themibrwaypf i lu tration. fztheincomp undi-ngzin.s asfat ul u a d likeingredients are concer ed-contain about at and /2 of active sulfur; ot rs .aare-ir e of ulfurcontent? nda conta n hl r ne-and. f ty matter,--such.- as 0.3% chlorine and;;14%; fatty matter;som e contain ;a sulfurized, ,fatty.acid base and a free, fatty acid oi-lz-others contain a sulfurchloride base and a small .or-negligible-amount of fat.- Such ingredients may. vary widelyasto theirnature and proportions: for example, another such;oi1 contains; 15% of rfatand 3%-of; sulfur. Such oilsand water. are notmutuallysoluble, and the non-solublegrinding oils that we -prefer to employare those distinguishable from so-called soluble oils or; pastes, or compounds which are intended to be and are, for grinding 'purposes, mixed with or dissolved in water, usually in a ratio on the order of l to 40; to be used in-grinde ing; operations whensomixed or dissolved with water. Illustrative grinding oils suitable for use in the high-pressure side of our-system are available on the market by the following identifications: White & Bagley Co. No. 1729,v Stuart Threadcut oil, SinclairWil .Kut oil, Windsor No. 1 of Anderson Co., Windsor Gear. Grinding oilNo. 300 of-FrErAnderson Co., StuartGrinding oil Super Kool 81X, International No.- 156.-Grindingoil, International-No. 152. Grinding oil,1 E F. Houghton & Co. Cutmax H-S, Houghtonstainless ThreadGrinding oil, and others.

Employing such grinding-oils in combination; with water, according to our invention and in the manner abovedescribed, grinding performance tests, in comparison ,to performance data achieved by following heretofore, known practices, show the, achievement of unexpected and outstanding results. For; example, considering thetraverse grinding operation .ofzthe kind above-describedin co neetionwith Figure using agr ndinewhe L ame" mascara oi: 2.0;? diameter-and2". width of perinheral. face... irreverence-rat, 1.1.5.03. .P. Momma-wo kpi ce of hardened .steel (Rockwell .051).. of, a. dime eter ofrz /zl", driven .at- .9QR..; P. M... ithza rate. f.

5;, relative-traversein axial directionbetw engrindeing; wheeland,work piece of 42'. p r minute, the. followin cflmparativedatawere obtained.

(a). Usin whitelnBae y Na. 1729 rinding. oil:on.the,high1.pressure side of oursy-stemrwith.

0: water..-on.=;-the. ow-pressure de. and takin -a radiahcut. of .mil, which means an index feed. of; one mfl,(0..0.01!') per pass or. traverse .fonfiity trairerses,. measurements. and observations i ldi-w cated .a wheel wearof 0, sixtr-aversesto. "die. out,, profil meterread n s f. the suriac finish at1 the; beginning and. at the. :end. .were,. respectively,.- l and ,-12,.and net power inputto the grindingyvheel, was- 2.6 kw.. Utilizing a .known commercially available solubleoil, dissolved or mixed with ,water in the..ratioof..1 1:0.40 and applied to. the same. grinding operationinaccordance with heretofore. known methods, the, wheel wear was. 2.0.. mils. (meaning..reduction in wheel diameter) for fifty traversesat an index feedof 1 mil, eight passes.

gr wererequired todie out, initial and final. pro-..

filometer readings were, respectively, 10.and 16,. and net power input. 4.0. kw..

(b). .Repeating the two just-described, com? parativetests, butwith-an index feed of.2.mils; p r. traverse, .andtaking the average, for four, sets of comparativeruns of 50 mils totalindex feed. perthe. comparative figuresare: When .pracr. ticing our invention, wheel wear was...-0.4,. mils,.; eight-die-outpasses, initial and final prqfilometer 35, readings of 10 and 22,.and net power inputof 4.5.

kw.; when following prior practice as described in. preceding paragraph (a), the wheel wear was fivetimes as great, namely, 1.9 mils, ten die-out passes, initial and .final profilometer readings were 10 and 48, and power inputwas 6.5 kw.

Comparative results in a traverse set-unlike thatofFigure 2, but operating upon soft crank-.-

shaft steel (Rockwell C20)., with a wheel surface speed of 6200 feet per minute. a work speed of-90. R. P. M. for a work piece of .2 inches in diameter and arate of relative traverse between grinding wheel and work piece of 42" per minute, and, with a total index feed of- 200 mils per run, were as, follows:

(c) A run made according to our invention and using the liquids mentioned inabove paragraph (a), with an index feed of 2 mils per traverse, the wheel wear was 1.0 mil, die-out passes were six, initial and final profilometer readings were 14 and 30, and power input 3.5 kw. By comparison, following known practice with the soluble oil solution described in paragraph (a), and again effecting an index feed of 2 mils per traverse, breakdown of the wheel face occurred at the halfway mark of the run or at about; after 100- mils of index feed; that would require re-truing in commercial practice but'the run was continued to the intended 200 mil total index feed. At the end of the run the wheel wear was nine times as. great, namely, 9.0 mils, it required fourteen-dieout passes, initial and finalprofilometer readings were 11 and 50, and the power input almostdouble, being 6.0 kw.

(d) Repeating these comparative tests, but taking an index feed of 4 mils per traverse, the following comparative data were obtained: When grinding according to our invention, the wheelwear was 0.5 mil, six traverses were used to.die out, initial and final profilometer readingswere- 12 and 55,and power input was 6.83%.. when 17' grinding according to prior practices using the solution of soluble oil and water described in P ragraph (a) above, breakdown of the wheel face occurred at about the halfway mark and hence-after an index feed of 100 mils had been effected and the run was continued to the intended total index feed of 200 mils. The wheel wear was sixteen times as great, being 8.0 mils,

the character of surface such that fourteen dieout passes were required, initial and final profilometer readings were 10 and 85, and the power input 8.5 kw.

In those runs described in paragraphs and (d) above which were made in accordance with our invention, the grinding oil was applied by way of three jets or streams projected by three nozzle elements having nozzle channels of it," diameter, the jets were spaced about 78 apart and centered in relation to the 2" width of grinding wheel face, oil pressure was 95 pounds per square inch, and the points of incidence of the jets upon the wheel surface about above the grinding line L as viewed in Figure 6, and the rate of flow of high-volume low-pressure Water in the stream C as in Figure 4 was about six gallons per minute. The same factors were present in the runs described in paragraphs (a) and (b) above. Also, the points of incidence of the high-pressure low-volume jets, in all of these runs, was just about of an inch above the grinding line and, referring to Figure 6, because the spread or fanning-out as at F F and F was appropriate to cover adequately the width of the grinding wheel face at the pressure employed, the nozzle elements I9, 20 and 2| were, in these runs, set so that their channel orifices 33 had a normal inclination, that is, their axes were in respective vertical planes parallel to each other as considered in Figure 5.

Since, in a set-up like that of Figure 2, a relative traverse in axial direction between the work W and the grinding wheel G took place, as by traversing the work holder and the work W back and forth in the direction of the arrow indicated on the work W in Figure 2, and grinding took place during each traverse stroke, it will be seen that, relatively speaking, the left-hand edge of the grinding wheel face P becomes the leading edge on one stroke and the right-hand edge becomes the leading edge on the opposite stroke. We have found that, apparently because of the controls effected as above described, such as high pressure and high velocity of movement of the grinding liquid or oil onto and downwardly along the grinding wheel face P, the movement of the work-piece in the course of its traversing strokes or the movement of the surface of the workpiece in counterclockwise direction, as viewed in Figure 1, has no material or consequential detrimental action upon the oil covering the grinding wheel surface in advance of the grinding line as might be expected at the leading edge or end of the operative surface of the grinding wheel.

In any case, however, anysuch action can be easily avoided as by insuring that the spread (see Figure 6) eifectedby the high-pressure lowvolume jet or jets is in excess of the width of the grinding wheel face. This can be effected, as will now be clear, by suitably inter-relating the various factors. Thus the pressure and hence velocity may be increased to increase the spread, or the'end nozzle element or elements may be set or adjusted to change the direction or angle of incidence of the emitted jet or jets as was described in connection with Figure 8 and thereby 18 also give the moving film or layer of oil inadvance of the grinding line a horizontal component opposing the direction of the relative traverse between the wheel and the workpiece.

Also, raising or lowering the high pressure low-- volume jets relative to the grinding line may also be resorted to, or any combination of this with any of the other control factors already de-.,

mensurate reduction in the need and waste and time consumption in trueing the wheel; invariably, and for reasons we are unable to explain, reduction in power consumption in unexpected magnitude is achieved and, virtually paradoxically, the reduction increases with increase in grinding duty or work imposed upon the grinding wheels; moreover, superior finish on the workpiece is achieved and a given grinding operation is further speeded up in that "dieout passes or traverses are less and even with lesser dieout passes better profilometer readings are achieved.

But still more impressive are the actions and results achieved where the grinding wheel is called upon to perform by way of its corner or corners, as in a set-up like that of Figure 3. Comparative tests directed to the measurement of breaking down or wearing away of the corner or corners may now be considered.

In the data about to be set forth, in those runs where our invention was practiced, a single lowvolume high-pressure nozzle element was employed, withits jet directed to strike the corner of the wheel at about of an inch above the grinding line, thus to cause the fanned-out or downwardly and outwardly diverging film or layer of oil to be divided substantially equally between the peripheral face of the wheel and a side face of the wheel, since both were to be operative upon different surfaces of the workpiece; a narrowfaced grinding wheel (two inch width of peripheral face) was employed to function by way of only one of its corners, in order to simplify comparative tests and avoid possible complication by having to consider what happens to both corners. In Figure 9, we have schematically indicated that grinding wheel G, operating by its peripheral face P and its side face P and at S we have indicated the point or area of incidence of the low-volume high-pressure stream or jet; that point or area is intersected by the corner of the wheel formed by the intersection of the trued faces P and P and the angle of incidence is chosen so that the fanned-out layer portion F of grinding liquid that is deflected by and onto the peripheral face P has a spread R about equal to the Width of the surface P, while the fanned-out layer portion F that is deflected by and onto the side face P has a, spread R at least equal to the radial dimension of the workpiece surface which it is to grind. That radial dimension, in the tests was on the order of of an inch. In Figure 10, the test workpiece is indicated at W it has a cylindrical portion 61, comparable to the crank pin CP- of Figure 3, which the face P is to grind, and it has an annular face 68 at right angles to the axis 69 of the workpiece W which is to be ground by the side face P and which hence is comparable to the face 6| of the crankshaft workpiece of Figure 3.

The grinding wheel faces P and P -are trued at right angles to each other with the plane of the face P at right angles to the axis of'the grinding wheel and the apparatus is constructed in any known manner. as above vnoted and as indicated by the arrows in Figure 10, to efiect relative movement between the wheel and the work carrier and hence the workpiece in a direction at right angles to the axis 69 of the workpiece and toward or away'from the latter. :Accordingly. at the beginning of the grinding step and with the workpiece W rotated at suitable speed and in suitable direction. the corner of the grinding wheel G first comes into grinding action upon the workpiece W as the relative approaching movement between the wheel and the workpiece is effected. becoming operative by Way of a narrow marginal portion of the peripheral face P (to the extent of the depth of cut or amount of metal to be removed at the face 68 of the workpiece) and also by way of the side i'ace P until the entire width of the peripheral face 'P engages the cylindrical portion 61 of the workpiece whence the grinding of the latter is continued to the desired extent, for example. until the desired diameter of part 61 is arrived at. The grinding-work burden imposed upon the corner of the wheel is. it will be seen. very severe and in a grinding operation like the set-up in Figure 3. such a burden is imposed upon .both corners. If the rate of relative approaching movement is too rapid. the corner breaks down or wears too rapidly. becoming out of shape -or irregular or rounded over .at a progressively increasing radius: these effects can become multiplied if the axial dimension of material being removed along the line of the face -(i8 is increased. the tendency here being to more rapidly increase the radius of rounding off of the corner. These actions singly or in combination thus cause the production of a fillet at 63 that is of an excessive radius or of greater radius than permissible. 'Io effect correction in order to get the fillet within permissible limits. the grinding wheel face P is trued off to restore the comer to sharpness. If the effort is made to avoid frequent truein which wastes the wheel and reduces its useful life. such effort has to be directed to taking lighter and more numerous cuts and to efiecting lower rate of relative feeding movement. thus prolonging the grinding operation and slowing up production.

In the comparative comer-grinding tes s. the grinding wheel is operated at a surface speed of a out 6.200 feet per minute. the workpiece W was rotated. where the d ameter of the part 67 was on the order of 2 inches and that of the lar er-diametered part on the order of 3 inches. at 76 R. P. M.. pressure of grinding fluid or oil as in the sin e let S of Figures 9 and '10 was on the order of 95 pounds per souare inch accompanied by a large-volume low-pressure column or flow of water at the rate of 2.5 gallons per minute. and the material of the workpiece was the same for all tests. being so-ca-lled soft crankshaft steel: also nozzle elements of different sizes of orifice channels, thus to change the volume of flow of the high-pressure low-volume liquid were employed. all as noted below. Corner wear was determined by a radius or fillet gauge, to determine the radius of the fillet at 63 in Figure 10 in 64ths of an inch.

' (e) Tests were first made according t0.heretoanaemia oil. dissolved or mixed with water-in the ratio-of about 1 to 40, that was used in the comparative tests in paragraphs (a), (b), (c) and (d) above. Radius of the fillet (in sixty-fourths of an inch) after the first cut, was 4.0, and after the fifteenth cut was 10.5, showing that the corner of'the wheel wore off by an increase in the radius of the corner from y to a net increase of 6.5 sixty-fourths. Net power input was 1.3 kw. These data are the-averages for several runs of the just-mentioned known commercially available soluble oil which,-based upon other-factors and tests, may be said to be the best or better than average, in performance of compounds of this nature, and for these latter reasons was selected as a standard elf-comparison against which to gauge performance data'when grinding according to our invention, of which the results and data of several tests are noted below.

(1) Using White 8: Bagley No. 1729 Grinding oil on the high-pressure side of our system and applied in a single stream 5* (see Figure 9) impinging upon the-corner as above described from a high-pressure nozzle having a channel orifice of a diameter of 76 mils, with water employed on the low-pressure side, fillet radius at 68 after the first cut'was 2.9, 'andafter the 15th out was 5.2.. withpower input of 1.0 kw; comer wear, in increase of radius, was only'2.3 sixty-fourths. Repea'ting this test with a'slightly difierent grinding wheel structure or grade, fillet radius after the first cut was 3.9, after the fifteenth cut was 6.4, and power input was 0.8 kw.; cornerradius incteased only'2.5 sixty-fourths.

(g) This test, repeated with, a lesser volume of grinding liquid in that a nozzle of orifice channel of 40 diameter was employed, showed that fillet radius as a result of the first cut was 2.9 and after the fifteenth cut was 5.5, with average power input of 1.0; comer radius increase was only 2.6 sixty-fourths.

(h) Repeating the last-mentioned test, but using on the high-pressure side of the system Stuart Threadcut oil, fillet radius after the first out was.3.5 and after the fifteenth cut was 5.9. and average power input 1.0 kw.; wheel corner radius increased only 2.4 sixty-fourths.

(i) Using the above-mentioned WindsonNo. 1 oil and a 76-mi1 nozzle, fillet radius after the first cut was 3.9, after the fifteenth cut was 6.8, and average power input was 1.0 .kw.; wheel corner radius increase was 2.9.

(7') Repeating this test with the above-mentioned Windsor N0. 300 oil on the high-pressure side of the system, fillet radius after the first cut was 4.9, after the fifteenth out was 7.2, and power input was 0.8 kw.; wheel corner radius increased 2.3.

(k) Repeating, but with International No. 156 oil on the high-pressure side, fillet radius after the first cut was 3.5, after the fifteenth cut was 5.9, and average power input 1.0 kw.; wheel cornerradius increased 2.4.

(l) Repeating with International No. 152 oil, fillet radius after the first out was 3.5, on the fifteenth cut was 6.2, and average power input was 1.0.-kw.; wheelcorner radius increased 2.7.

(m) Repeating with the above-mentioned Houghton Stainless oil on the high-pressure side, fillet radius after the first cut was 3.5, after the fifteenth cut was 5.4, and power input was 0.8 kw.

In test (e) the wheel .corner wear .or increase inradius at the comer willhe be seen to .be at the razteof 6.5 sixty-fourthsior 14cutsand1nay fore known methods, utilizing the same soluble (a be said to be the optimu r best performance according to best heretofore known methods, ma- 7 terials and practices; that took place at a power input to the grinding wheel or machine of 1.3 kw. In tests (f) to (m) of performance achieved by our invention, power input is invariably reduced onthe order of 25%, and the rate of corner wear averages 2.4 per 14 cuts, the lowest corner wear figure being 1.9 and the highest being 2.9. The rate of corner break-down or wear is thus seen to be reduced in the ratio of about 6.5 to 2.4; the need to true the wheel, when usin our invention, may thus be said to occur only /65 as often as according to most favorable heretoforeknown practices; or, generally speaking, the grinding wheel, once trued, when practicing our invention, will operate /24 as long as the same wheel will operate according to best heretofore known practices. This relation is, however, shown by test to be non-linear and the need for truing is reduced to something like A as often, Or the wheel, once trued, will operate four times as long. At the same time, material savings in power are accomplished, not to mention increased production, in that stoppages of work required for wheel truing are reduced. Incidentally, these data are ,of interest also when compared to performing the same grinding operation by using only water; one such test (n) gave a fillet radius or breakdown after the first cut of 6.5 and after the fifteenth cut of 17.0, and note the vast increase ln power input, which was 1.8 kw.; here cozner wear was at the rate of 10.5 per fourteen cu s.

As earlier above noted, our invention is applicable to other forms of grinding operations than those indicated in Figures 2, 3, 4, 6, 8, 9 and 10, and an illustration of another form of grinding is surface grinding, diagrammatically indicated in Figures 11 and 12, in which the grinding wheel G operates upon a work piece W which is suitably supported on a bed or table 1| arranged in any suitable way, as in typical surface grinding machines, to be moved or traversed back and forth (to the right and left in Figure 1, as indicated by the arrow 12) in reversible strokes of suitable length to traverse the upper face of the work piece W in successive strokes re'ative to the grinding wheel, the table II being provided with any suitable means, also usual in surface grinding machines, to give the table II and, hence, the workpiece W carried by it a suitable cross-feed (to the right or left in Figure 12, as indicated by the arrow '13), usually step by step and suitably timed with relation to the traversing strokes of the table H. Illustratively, the apparatus may be operated so that the grinding wheel operates to grind the surface of the workpiece W on each stroke to the left and to the right, as seen in Figure 11, and the crossfeed indicated in Figure 12 may take place, or its increment of feed completed, at the end of each stroke of the table 1 I.

The active liquid and the coolant may be applied in various ways or combinations, utilizing both angular spaces between the grinding wheel and the work that are present, respectively, to the right and to the left of the grinding line L, as viewed in Figure 11. For example, the grinding oil may be directed to the grinding line in a stream or streams from the left in Figure 1, and the liquid coolant from the right, or vice versa; or the grinding oil may be directed from either side alone, and the coolant liquid applied to the workpiece W on both sides; or, by suitable table-controlled valves, the grinding oil and coolant liquid applied alternately at the two angular spaces in synchronism with the working strokes of the table II; or the liquid coolant always applied at both angular spaces, and the grinding oil, under the control of suitable table-actuated valves, applied alternately at the two angular spaces in synchronism with the working strokes of the table N. All such arrangements give superior results over prior practice, and the lastmentioned one is preferred because maximum coolant liquid is continuously applied to the workpiece to withdraw generated heat and a minimum active liquid is used, and, hence, a lesser burden is imposed upon the separating apparatus or system 56.

In Figure 11 is diagrammatically shown the setup for carrying out this last-mentioned preferred arrangement. Thus, two nozzle devices II are employed and supported in any suitable way, as from the grinding wheel guard (not shown), to direct the liquids they discharge into the angular spaces, respectively, to the'left and to the right of the grinding line L. The largevolume nozzles l2 are connected, by conduits l5 and 15 to the conduit l5 of the coolant liquid circuit, and preferably valves 15 and 16 are provided in each of the pipes l5 and I5", so that the rate of flow of coolant liquid may be set or controlled for each nozzle device H. The distributor blocks 36 of the nozzle devices are connected, by pipes 23 and 23 to the conduit 23, but, through a two-way valve 11, provided with an upstanding actuator or control arm 18, positioned in the path of movement of spaced blocks and 8| adjustably secured to the table II and so positioned that at the end of each stroke of the table one of these blocks engages and turns the valve lever 18 to cut off the flow of active liquid to the high-pressure nozzle or nozzles of one of the discharge devices and to connect the high-pressure nozzle or nozzles of the other discharge devices H to the grinding oil supply line 23.

With such an arrangement, thereforeand assuming that the grinding wheel G is driven in clockwise direction, as indicated by the arrow-if the table H is moving to the right, coolant liquid is emerging from the mouths M of the two lowpressure nozzles 12, spread substantially uniform- 1y over the surface of the workpiece W from which it runs off, carrying with it absorbed heat and thus preventing rise in temperature of the workpiece, and during this stroke toward the right, valve "i7 is in a position to cut off the flow of active liquid in the pipe 23 and to maintain flow of a grinding oil, through pipe 23", to the nozzle or nozzles of the right-hand nozzle device it, that condition continuing until valve-operating block 80 trips the valve lever 78, whence the flow of grinding oil to the right-hand nozzle discharge device H is stopped and the flow of grinding oil to the left-hand discharge device ll commenced. This changeover occurs just about at the end of the stroke of table II to the right and conditions the flow of grinding oil for the reverse or leftward stroke of the table H, whence the valve-actuating block 8|, at the end or reversal of the leftward stroke, effects a resetting of the valve 11, as will now be clear. The low-volume,- grinding-promoting liquid is thus always supplied to the grinding line at what may be termed the leading side thereof, and maximum heat withdrawal may be effected by maintaining continuous flow of the high-volume, low-pressure coolant 23 liquid to the .work .on-both the leading .andtrailing sides of the grinding line.

If itis desired to alternately discharge coolant liquid onto the workpiece .at the leadingand trailing sides of the grinding line, a two-way valve Sit-whichmay-be arranged, as by .an operating lever -84, also to be actuated by table stops B- and BI -may be .interposed between the .main conduit I and the branch conduits 15*.and l5 which lead to-discharge devices I I, as is. shown in Figure 13.

With such arrangement various combinations of control of coolant liquid and grinding liquid may be carried out, some of which are indicated above; for example, the two-way valves may beso constructed that they have a mid-position in which the liquid is passed to both branch .pipes so that, when automatic-actuation of either or both of them is not-desired, the valve-actuating blocks on the table maybe removed or spaced apart more, and .the two-way valve manually set for discharge into only one of the branch pipes or for discharge to both branch pipes.

For surface grinding, advantages and superiority of results comparable to those earlier above set forth in connection with cylindrical grinding, .are achieved. Moreover, asubstantial range of change of relative conditions between grinding wheel workpiece and the two liquids applied thereto is possible, while retaining, in general, the unique advantages and results achievable by the invention, some of .which .are earlier above set .forth in detail. .-For example, the point or points .at which the grinding liquid is applied may be subject tosome variation. Thus-good results are achievable if the grinding oil, with a relatively narrow grinding wheel face, is applied substantially at the corners'of the wheel, as at S and S in Figure 8, the .narrowness of the wheel face not necessitating an intermediate stream or streams of grinding oil. In-other words, with a narrower wheel, a stream as at S in Figure 8 can be eliminated. On the other hand, a single stream, directed substantially at the mid-point of a narrowfaced grinding wheel, permitting adequate spread of the active liquid throughout the transverse extent of the grinding line L, has also been found to give good results. Moreover, under some circumstances, the active liquid need not be directed against or applied directly to the grinding wheel face, and this may be carried out with greater facility in surface grinding where, for example, the active liquid, particularly at the right of the grinding line L in Figures 11 and 13, with the grinding wheel turning in clockwise direction, may be permitted to discharge onto the surface of the workpiece W just to the right of thegrinding line L. This may also be done at very low pressure of discharge or at very low velocity, if the windage caused by the grinding wheel aids in drawing the grinding oil into the apex of the angle and to the grinding line while, also, relatively large-volume coolant liquid emerging from the coacting large nozzle l2 contributes to the action of virtually pushing or flowing grinding oil discharged onto the surface of the workpiece W in a direction toward the grinding line L. Because principally of windage effects in an opposing direction, the grinding oil discharged to the left of the grinding line L in Figures 11 and 13, is preferably discharged, if onto the workpiece W, at a sufficiently high pressure or velocity to get it to the grinding line L in opposition to such windage effects. It may, however, also be directed to both the grinding wheel face :and the surface of the rags-e workpiece, .or onto either of them alone-as will now be clear, and its .velocityof application or the pressure at which itv is supplied to the discharge orifices or nozzle, may varyconsiderab'ly, depending upon physical or mechanical factors present in the .particular grinding machine arrangement, the principal consideration here .being that the grinding oil be gotten to the grinding line as little commingled with coolant liquid or water as possible, and it will thus be seen that circumstances can exist to bring this about without having to subject the grinding-promoting liquid to substantial pressures or to high velocity. The rate .of supply of the active liquid to the grinding line is. such that, in quantity, it is supplied to or present at the grinding line large enough materially to promote and aid the cutting and grinding action, and the coolant liquid should be supplied at a rate commensurate with the grinding duty being performed and, hence, the rate Of heat production, so that the heat produced is removed without substantial rise in temperature of the grinding wheel (considered from the viewpoint of grinding wheel operating temperature) so that, also, the grinding oil can operate most efficiently-that is, at relatively low temperature-and the workpiece itself is prevented from such rise in temperature as may be dictated by the permissible tolerances or by such other factors as facility of manual handling.

At the grinding line it is possible that comminglingof some of the grinding oil and of small amounts of coolant liquid take place. The relatively large quantity of coolant liquid and relatively small quantity of active-liquid, applied to the grinding wheel and the workpiece, are, .as earlier above noted, preferably caught, as in the pan 54 of the machine, whence they are passed onto the separator 56 in a more or less mixed state, but, being insoluble one in the other, the liquid that passes onto the separator system 56 is essentially a mechanical mixture. Carried with it is so-called swarf, which comprises the small particles of the material ground off of the workpiece and the small particles of the grinding wheel composition, including fragmentary abrasive grains, etc., etc. The swar'f settles out mechanically relatively easily, but, in order 'to achieve certain additional coactions and advantages, we prefer to separate out the active liquid or oil constituent from the coolant liquid by the aid of heat, and then, after suitable treatment, to return the separated active liquid and coolant liquid to the grinding wheel and work, respectively, and in Fig. 14 is shown diagrammatically an illustrative and preferred form which the separator 56 of Fig. 1 may be given in order to achieve additional coactions and advantages.

In Fig. 14 the commingled or mixed grinding oil and water are received from the collecting pan of the grinding machine by way of the pipe 55, as already above described, the mixed liquids carrying with them a certain amount of swarf; all of this is preferably discharged into one end of a relatively long and wide trough 86, arranged at a slight incline (downwardly toward the right in Fig. 14) so that the mixed liquids from the machine can flow relatively slowly and at .low or shallow depth throughout the substantial length of the trough, illustratively about six feet in length.

The discharge and of the trough ,86 overlies one end of a relatively large-.capacitytank .81; the tank, illustratively, may. be of .a capacity on 25 the order of 200 gallons, and the mixed liquids are discharged into one end of the tank (the right-hand endin Fig. 14) and, if desired, suitable screen-like filtering means 89 may be employed to mechanically separate such of the swarf as might. be carried along with the discharge from the trough 86. The tank 81, which is preferably substantially elongated in horizontal direction as seen in Fig. 14, may be provided with a battle or partition 90 at the receiving end thereof, thus to provide a receiving chamber 9i into which the discharge from the trough 86 impinges. From the receiving chamber 9I the mixed liquids pass over the top edge of the partition or baffle 90 into an intermediate chamber 92 of substantial capacity in relation to the rate of flow of liquids in the system, so that the mixed liquids in the chamber 92 are relatively undisturbed or quiescent, quiescence beingaided if desired by intermediate baflies as indicated; the baffle or partition 90 prevents any turbulence due to inflow of mixed liquids from the trough 85 from unduly agitating the liquids in the chamber 92, the transfer of mixed liquids over the top edge of the partition 90 taking place with little intensity of flow because of the appropriateness of the length of the baiile 90 in relation to the rate of movement of liquid in the system. In the receiving chamber 9|, substantial settling out of swarf takes place so that mixed liquids transferring over the bailie 90 into the intermediate chamber 92 contain less solid matter or particles.

In the intermediate chamber 92, the left-hand wall of which is in the form of a bafile or partition 93 that is of lower height than the partition 90, the relatively large body of mixed liquids is, as above noted, relatively quiescent and a separation takes place, the water moving downwardly and the grinding oil moving upwardly so that, with the level of the liquid in chamber 92 bein about as indicated by the broken line 95, a more or less well-defined horizontal plane of demarkation, as indicated by the broken line 91, comes into beingand continues as the flow of mixed liquids into the chamber 92 and withdrawal therefrom of the separated liquids continues. There is, thus, in the chamber 92 a relatively deep layer 98 of water underlying a relatively shallow layer 99 that is principally of grinding oil, but contains a small quantity of entrapped water and also a small quantity of oil-water emulsion, the emulsifying having taken place as a result of the mechanical action at the grinding line upon some of the oil and such small quantitle of water as may have gotten to the grinding line. The layer 98 is of materiall greater depth than that of the layer 99, being, roughly, in the ratio of the rate at which the coolant liquid is supplied to the grinding apparatus to the rate at which the active or promoting liquid is supplied thereto. This ratio is relatively high and, hence, there is a substantial vertical distance in the intermediate chamber 92 throughout which the lower specific gravity of the grinding liquid can be made effective to bring the parti cles of grinding liquid upwardly away from the bottom of the chamber and into the upper layer 99. The coolant, therefore, is practically clear water adjacent the bottom of the chamber 92 and, hence, we prefer to withdraw it at this point for supply to the grinding apparatus. Thus, a conduit I connects through the bottom wall of the intermediate chamber 92 so that the separated coolant liquid may be withdrawn and sup- 26 plied to the conduit 51 (see also Fig. 1) to be led to the grinding apparatus, as by way of the pump 52, conduit I5, and discharge nozzle I2 above described.

The liquid that spills over the left end wall or bafiie 93 of the chamber 92largely oil, with some oil-water emulsion-enters what may be termed a collecting chamber I02 at the left end of the tank 81, and this chamber I02 is also preferably of substantial capacity so that some separation by gravity may continue to take place in the mass of liquid collected therein, the water, and any entrained solid particles that may accompany it, going to the bottom and settling out in a bottom layer, the amount of water in the liquid discharged into collecting chamber I02 is, however, relatively small and the separated water may be drained from the bottom from time to time in any suitable Way. as by a drainage conduit I03 provided with a valve I04.

From a suitable point well above the maximum depth of separated water in the collecting chamber I02, the grinding oil, with the oil and water emulsion and now a still lesser amount of Water, is withdrawn, as by a conduit I06, and passed through a heat-exchange device in the form of a heater I01 of any suitable or desir ednonstruc- NW N y raise the temperature of the liquid appropriate to eflect final separation of the oil, water and oil emulsion, and water into a substantially clear oil component and a substantially clear water component. A suitable temperature for this purpose may be on the order of from 6, o to 00 dereesF.,

and, so heated, the quid passes, by way .0 .con-

duit I09, to a tank H0, conveniently called the hot tank." Hot tank H0 is preferably'of relatively large capacity in relation to the rate of flow of active liquid in the system and, illustratively, may have a capacity on the order of 30 gallons. The high-temperature mix enters the tank I ill at a point about midway between its top and bottom, and in the tank the liquid mix is sufficiently quiescent so that, under the efiects of the heat, the oil separates out, going to the top, the water going to the bottom. The water and oil emulsion is broken down and separated into its components of oil and water, and this action, under the effects of the heat, may be accelerated or aided, if desired, by the addition of small quantities of compounds such as alum, in known manner, for breaking down oil and water emulsions; such additions may be effected in any suitable manner, as by initially charging therewith the quantity of water with which the circulating and separating system is initially supplied.

The heating is of advantage, particularly with the more viscous grinding-promoting liquids, in that it increases their fluidity and, in the hot tank H0, thus accelerates the release of particles of swarf which'by their own weight move down to the bottom of the tank II 0 from which they may from time to time or otherwise be removed in any suitable manner, a drain and valve indicated at I25 being provided for such purpose, if desired, or for purposes of draining of the tank when necessary in cleaning the system.

On the other hand, we may operate our system without the application of heat, in which case the heater I0! is suitably constructed so that its heating action may be cut out; thus it may embody an electric heating unit I08 controlled as by a switch I05 by which it may be out 01f from its source of energy. In such case it is desirable 27' to use additions such as alum above mentioned to aid in breaking down the emulsions in the tank I I 0. Separation of residue swarf can continue in the tank H or other means later mentioned may also be utilized to aid in finally separating out the residue swarf.

From a point in or near the bottom of the hot tank III! a conduit II I withdraws the separated water from the bottom layer in the tank, and such separated water may be returned to the system at any suitable point; being relatively small in volume and hence in rate of flow, it may be returned to the receiving chamber SI of the main separating tank 81, as is indicated in Figure 14, or if desired it may be bled into the conduit Hill by way of a cross-conduit H2 having therein a check valve IIZa, thus adding the separated coolant to the previously separated coolant moving in conduit I00 from the intermediate chamber 92 of the tank 81.

From an upper point in the tank I III a conduit II 3 is connected to withdraw the separated active liquid or oil, whence it is ultimately passed through a heat-exchange device H4. Preferably a suitable filtering means indicated at H5 is provided to keepthe active liquid flowing out of tank III] by way of pipe H3 as free of residue swarf as possible, and this filtering means H5 is preferably employed both when the liquid is heated in the heater I01 and when the heater is not made efiective. The heat exchange device H4 may be in the form of a cooler of any suitable or desired construction appropriate to withdraw heat from the separated oil, not only the heat which the oil gained in the heat exchanger I01 if the latter is made efiective but also heat which it may have gained at the grinding line or from commingling with the coolant liquid as it commingles with the latter in the grinding machine or the collecting pan of the latter, it being noted that the coolant liquid is raised somewhat in temperature as a result of its heat-abstracting action upon the work piece. The cooler H4 which may, for example, be a mechanical refrigerating unit, reduces the temperature of the oil to any amount desired and suitable, and this may be to a temperature materially below room temperature, if desired; and the oil, passed on to the grinding machine from the cooler II 4, by way of the conduit 58 (Fig. 14 and Fig. 1), and conduit 23 and the nozzles I 9. can thus be supplied at the grinding line at substantially constant temperatureand, moreover, at a reduced temperature-so that its capacity for absorbing heat energy dissipated at the grinding line is materially enhanced.

At the same time it is preferred to abstract heat from the separated coolant liquid before it is returned to the grinding apparatus, and heatabstracting devices, or cooler H4. may be arranged to effect cooling of the water after it is withdrawn from'the intermediate chamber 92 and before it is supplied to the distributing conduit 51. as indicated in Fig. 14.

Thus, the heat taken up by the coolant liquid in the grinding apparatus and abstracted from the workpiece may be removed and the coolant liquid returned to the grinding apparatus at a constant temperature, which may be any suitable temperature, such as at or below room temperature, and thus its capacity for heat absorption from the workpiece increased or maintained constant, or both, With similar control, as above mentioned, of the temperature of the active liquid uniformity of temperature conditions in the grinding apparatus during grinding operations may be maintained throughout long, "continued, successive grinding'operations' upon successive workpieces, and thus it is made possible to work dependably within close tolerances in the quantity production of workpieces or parts unaffected'i'n any detrimental way by heretofore uncontrollable variables, particularly as to temperature conditions of operation.

We, therefore, preferably provide for the automatic temperature control of the active liquid and the coolant liquid supplied-to the grinding wheel and workpiece, and, by way of example,the cooler I It may comprise two thermally-segregated coolers H4 and H4 thermally insulated from each other, as by a suitable insulating barrier I I4". Cooler I-HI may comprise a coil H3 through which the oil passes as supplied by the pipe H3,

and cooler I It may comprise a coil I'IlIl through which passes the water supplied by the pipe I00. Any suitable means, indicated at H6, may be provided to supply to the coolers Ht and Ht any suitable low-temperaturefiuid-such as brine or evaporatable refrigerant, such-as is employed in mechanical refrigerants-through conduits H1 and H8, respectively, with return-flow conduits H9 and I20, respectively, preferably by suitable means responsive to the respective temperatures of the oil in pipe 58 and the coolant-liquid in pipe 51. Thus, for example, a suitable temperatureresponsive element I2I in the pipe-line 58 can be provided to control a valve 122 in the .pipe H1, and a temperature-responsive device I23 in the pipe-line 57 can control a valve M4 in the pipe I I8; these-devices-may be-of any known or suitable construction, andthe rate-of'supply of refrigerant or coolant fluidto the heat abstractors IHI and I-I l may thus be controlled to give substantial constancy of temperature, at any desired equal or different levels for the active liquid and the coolant liquid as'may be desired.

It willthus be seen that there has been provided in this invention a method and apparatus in which the various objects above noted together with many thoroughly practical advantages are successfully achieved. The method and apparatus will be seen to be of wide adaptability to various kinds or types of grinding operations, some of which are above mentioned by wayof illustration, andfor any particular grinding operation controls of various variables are providedv so that the method and apparatus may be readily accommodated to the requirements of any particular grinding operation. Thus, for example, the active fluid may be brought to the region of grinding contact between the grinding wheel and the work piece, sometimes at high pressure and high velocity and at other times under widely difiering conditions, but always in such coaction with the high volume coolant liquid and with related factors such as character of the workpiece, wheel windage, or the like as will achieve at the grinding line or region of grinding contact appropriate absence of substantial commingling of the two liquids; other controls of variable factors for such purposes as have been mentioned may also include, as is clear in view of the foregoing, adjustmentor predetermination of angles of incidence of the various streams of liquids employed not only relative to each other but also relative to the grinding wheel and the work piece. For example, rotational setting of such nozzle elements as the element I9 of Figure 7 or replacement thereof in its mounting by a nozzle element whose discharge channel 33 has a different angular relation to the axis of the element I9 can effect'apin relation to the setting of the nozzle device H of Figures 1, 11 and 13 as a unit relative to the grinding wheel and work piece, and for this purpose any suitable form of universally adjustable mounting or support therefor, diagrammatically indicated in the drawings at X, may be employed, the various conduits having suitable flexible portions to facilitate such adjustments. Thus in the drawings the nozzle devices ll may be raised or lowered or their angle of tilt, as about an axis normal to the plane of Figures 1, Hand 13, may be varied at will.

As many possible embodiments may be made of the above invention and as many changes might be made 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.

We claim:

1. The steps in a method of performing a grinding operation upon a work piece which comprise supplying separately to the place of grinding contact of the grinding wheel with the work piece and to the work piece an active grindingpromoting liquid and a coolant liquid respectively for promoting grinding action by the grinding wheel and for abstracting heat produced by the grinding operation respectively, said two liquids being mutually insoluble and being of different specific gravities, subjecting the resultant swarf-containing mixture of active liquid and coolant liquid and emulsions thereof to separating treatments which include separating out at least some of the swarf, utilizing the dilierence in specific gravities of the two liquids to efiect separation of a major portion of the liquid coolant for re-supply thereof to the work piece, heating the remainder of the mixture to break down emulsified portions thereof and to separate out the active liquid and to increase the fluidity of the mixture to separate out the swarf carried by it, abstracting heat from the separated active liquid to lower its temperature, and re-supplying the separated coolant liquid and lower-temperature active liquid to the work piece and place of grinding contact respectively.

2. The steps in a method of performing a grinding operation upon a work piece which comprise supplying separately to the place of grinding contact of the grinding wheel with the work piece and to the workpiece an active grindingpromoting liquid and a coolant liquid respectively for promoting grinding action by the grinding wheel and for abstracting heat produced by the grinding operation respectively, said two liquids being mutually insoluble, collecting the mixture of commingled active liquid and coolant liquid and emulsions thereof produced at the place of grinding, treating the mixture and emulsion with the aid of heat to separate out the active liquid from the coolant liquid, withdrawing heat from the separated liquids, and re-sup plying them separately to the grinding operation as aforesaid.

3. The steps in a method of performing a grinding operation upon a workpiece which comprise supplying separately to the place of grinding contact of the grinding wheel with the workpiece and to the workpiece an active grindingpromoting liquid and a coolant liquid respectively 30 for promoting grinding action by the grinding wheel and for abstracting heat produced by the grinding operation respectively, said two liquids being mutually insoluble, collecting the resultant mixture of commingled liquids, separating out a major portion of one of the liquids from the mixture, completing the separation of the remainder of the mixture by the aid of heat, ab-

stracting heat from at least one of the liquids separated out by the aid of heat, and returning separated active liquid'and coolant liquid separately to be supplied separately to the grinding operation as aforesaid.

4. The steps in. a method of performing a grinding operation ,upon a workpiece which comprise supplying separately to the place of grinding contact of the grinding wheel with the workpiece and to the workpiece an active grindingpromoting liquid and a coolant liquid respectively for promoting grinding action by the grinding wheel and for abstracting heat produced by the grinding operation respectively, said two liquids being mutually insoluble, separating the resultant mixture of commingled active liquid and coolant liquid, and returning themseparately for resupply separately to'the grinding operation as aforesaid.

5. The steps a' method of performing a grinding operation upon a workpiece which comprise supplying separately'to the place of grinding contact of the grinding wheel with the workpiece and to the workpiece an active grindingpromoting liquid and a coolant liquid respectively for promoting grinding action by the grinding wheel and for abstracting heat produced by the grinding operation respectively, said two liquids being mutually insoluble, separating the resultant mixture of commingled active liquid and coolant liquid, and returning each at substantially constant temperature for resupply separately to the grinding operation as aforesaid.

6. The steps in a method of performing a. grinding operation upon a workpiece which comprise supplying separately to the place of grinding contact of the grinding wheel with the workpiece and to the workpiece an active grindingpromoting liquid and a coolant liquid respectively for promoting grinding action by the grinding wheel and for abstracting heat produced by the grinding operation respectively, said two liquids being mutually insoluble, separating the resultant mixture of active liquid and coolant liquid, and returning them separately, with at least one of them at constant temperature, for resupply separately to the grinding operation as aforesaid.

'7. The steps in a method of performing a grinding operation upon a workpiece which comprise supplying separately and respectively at a low rate and high rate a grinding promoting liquid and a coolant liquid to the place of grinding engagement of the grinding wheel with the workpiece and to the workpiece, said coolant liquid and said grinding-promoting liquid having different physical properties adapting them respectively for taking up heat and for promoting grinding action, collecting the resultant mixture of commingled grinding liquid and coolant liquid with the coolant liquid preponderant over the grinding liquid in the mixture, separating out from the mixture the major portion of the coolant liquid contained therein, separating out the grinding liquid from the remaining portion of the mixture, and. returning the separated

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