US2582702A - Abrading apparatus - Google Patents

Description

Jan. 15, 1952 w L, KEEFER 582,762

ABRADING APPARATUS Filed May 15, 1936 I5 Sheets-Sheet 1 I i J I I I I V i x a 5 [Wk/fer j, fig? Jan. 15, 1952 w. KEEFER ABRADING APPARATUS 3 Sheet at 2 Filed May 15, 1936 Jan. 15, 1952 Filed May 13, 1956 W. L. KEEFER ABRADING APPARATUS 3 Sheeis-Sheet 3 Patented Jan. 15, 1952 2,582,702 ABRADING AIIPARATUS' Walter L. Keefer, Hagerstown, Md., assigncr to Pangborn Corporation, Hagerstown, Md., a

I corporation of Maryland Application May 13, 1936, Serial No. 79,559

This invention relates to abrading apparatus and more particularly to mechanical apparatus for propelling abrasives at abrading velocities.

Abrasive throwing wheels having bladed rotors have been known in the art for many years, and.

although they are now going into rather wide use they are open to the objection that valuable time is lost changing blades. The blades of abrasive propelling rotors must be made removable, so that they may be replaced when they have worn out, and yet must be held so securely that they will resist the tremendous centrifugal force exerted when the wheel is operating.

Also, in centrifugal abrading machines wherein the abrasive is fed to the blades through an opening in a central feeding device and the discharge is directionally controlled, it has been found that when large. volumes of abrasive are fed to the machine the discharge stream widens out to such a degree as to render the same undesirable for certain installations, for instance when the machine discharges into a work tumbling barrel or drum.

The centrifugal abrading machines in use today are open to the further disadvantage that the blades wear out rapidly, which entails high maintenance costs. The blades would have a reasonable life if the wear occurred uniformly throughout the width of their propelling surfaces, but it has been found that through casting or other inaccuracies, substantially all of the abrasive admitted to each blade will take a course in a localized stream thereover when the blades are first placed in use, and as time goes on the blades will be deeply worn in this particular region with the result that all of the abrasive traversing the blade will take this course, producing rapid break-down of the blade.

It is a primary object of this invention to provide an abrading machine blade assembly that securely holds the blades in place and yetpermits them to be removed and replaced in a minimum of time. 7 a

It is a further important object of the invention to provide a novel blade assembly for abrading machines that will hold all of the blades securely in place while the machine is operating, will permit easy and rapid removal and replacement of the blades when they wear out and which will also permit the blades to be removed and replaced in the machine in a different relationship to present different surfaces to the abrasive when certain of their surfaces have become worn.

A further object is to provide, in an abrading machine having a bladed rotor for propelling the blades of the invention.

7 Claims. (0]. 51-9) M abrasive, a novel blade mounting assembly which will securely hold the blades in place and will not work loose during operation of the machine, and which will permit the blades to be quickly and 1.: easily removed from the rotor.

It is another object to provide a feeding mechanism for an abrading machine which will deliver abrasive to the inner ends of the propelling blades in such manner as to enable the machine to deliver a concentrated stream of abrasive, even when abrasive is fed thereto in large volumes.

A further object is to provide an abrading machine with means for throwing the abrasive splash back into the blades in such a. region as to cause the abrasive to discharge from the blades as though the splash had not occurred.

A still further object is to provide abrading machines with blades having means for causing the abrasive to take definite paths thereover, for

rendering uniform the wear that occurs thereon.

My invention also aims to provide an abrading machine with propelling blades which are so formed as to impart wear and friction reducing action to the abrasive as it passes thereover.

It is also an object to devise blades for use in an abrasive throwing rotor which will produce a minimum blocking action and consequently a minimum splashing action when abrasive-is fed over their inner ends.

Another object is to provide an abrading machine with an adjustable feeding device and to provide the adjusting device with means for making it possible to disassemble the parts without disturbing the adjustment of the device.

A further object-is to refine and improve certain detailed features of centrifugal abrading machines. I v

Further objects of the invention will become apparent as the specification proceeds in connection with the annexed drawings, and from the appended claims.

In the drawings:

Figure 1 is a side elevational view of an abrasive propelling rotor equipped with the blade assembly of this invention, with parts thereof broken away in order to more clearly illustrate the structure involved. I

Figure 2 is a' view looking at the wheel of Figure 1 from the right-hand end of that figure, with parts broken away for clarity of illustration. Figure 3 is an enlarged fragmental sectional view illustrating the manner in which the blades cooperate with their locking screws.

Figure 4 is an isometric view of one of the Figure 5 is a transverse sectional view taken on the line 5--5 of Figure 1, looking in the direction of the arrows.

Figure-=9 is alongitud-inal sectional viewofa v further form of blade of the invention.

Figure 10 is a longitudinal sectional view of a further modified form of blade of the invention- Figure 11 is an end view of the blade shown in Figure 10. V

Figure 12 is a-longitudinal seetional'viewofa still further modified form of abrasive propelling blade.

Figure 13 is a rear view of a modified form of y centrifugal abrading machine also forming partof myjinyention and which shows a modified form of ad iugting mgchanism and indicates an inspeca tion. and vService 'doorfor the wheel housing;

' Figure 14 is ailongitudinal sectional view'of- -th machine shown in Figure 13 and is taken .suble stantiall von line |4 l4 oi -that figure.

lIV-ithcontinued reference to' the drawings,

whereinjlike reference characters -have been em-r ployed to designate like" partsthroughout the several yiews thereof; the rotor-is designatedat RI nti-111.115 rig y Btermirrate"shorter-the cen e rt0 define a; central abrasive admitting: spacein whichan abrasive feeding deyice-F-issupportedforrfeeding a stream of abrasive'over the-inner end 10f blad s 'B- The f it effects, directional discharge of the abrasive thrown'from. the wheel, but; it "is to be understood that insofaras the blades andblade mountingare concerned; the invention is not limited to-a particular feeding :device but may be applied toany type. of abrading machine; ,7 For instance,

feet ling device 'F"may assume the form-of-a pipe- Secured to the face of rotor R,-by -a plurality; of

countersunk screws I l are four symmetrically arranged plates l2:- The radial edges" of plates P2 are providedwith bevelled faces l3; and theadjacent edges of each pair of plates -defi-ne a dove-tail groove- M; as seen Figure-l Blades B are provided withcorrespondinglydove-tail shaped bases to fit in" grooves 14; andhave inclined faces l5 cooperatingwith walls=-l3 of plate's lt The" inclined-faces 15 of-bladsB merge into abrasive propellingsurfaces l 6--pro-- vided on-each-side of the blade.- 'As -seerrin' 1=ig-' ure- 1,- inclined faces l5 merge with plates 1 2 in'a region spaced from their propelling-'surfacesflli, with-*the result that= the abrasive=moving outwardly oversurfaces l6- issmaintained=out ofabradingacontactl with-plates [2; which are, permanent parts of'themachine; The-free edges of blades B are each provided with a flange or ridge I! to confine-theoutwardlymovingabrasive toLsurfaceS: l6; a c

The blades are accordinglymountedlfor guided secured to a shaft HT; Shaft l 0. 15. mounted for rotation in'an-y desired bearing a sembly (not"'shown) and 1'0t0r-'R.' carr1es- -a plurality offabrasive propellingblades -B.- Blades eed'device will'be presently described-and movement toward and away from the axis of the rotor, and although grooves M, which constitute the guideways, are shown as being disposed substantially radially, it is to be understood that they may be inclined forwardly or rearwardly with respect to the direction of rotation if desired without departing from the uspiritjof the-invenion:

The means employed for, restraining blades B against outward movement preferably takes the form of a screw IB, threaded into rotor R adjacent-'thegouter end of each guideway I4. Each screw isprovidedwith a hex head I9 which projects-into a-recess 2| in the base of each blade BIQ JQ"gQqpdraitflshwith a wall 22 thereof to positively arrest outward movement of the blades. Thegfiatrsides ofhead I9 provide a large bearing surface for wall 22 and also prevent screws l8fro'm working loose in operation.

Referring to Figures 2 and 3, wall 22 and its opposite-wallare spaced -apart= a distance which is greater than-the-greatest diameter'of hex heads l9,-wi-th -the result that 'blades B can be slipped into place ingrooves Mend screws lfi turned up until they assume-the position shownin Figure 3; Blades B may then be-pulled outwardly until taking the-formof-a split resilient ring, encircling feed device F and engaging the inner ends of the blades; may --be used to positively hold them in engagement with' screws l 8.

Although screws I8 may beprovided with any suitableformation to permitthem tobe turned home witha wrench they are preferably internally formed with a hex socket-23 morder that v the screws maybe-so dimensioned as-to lie flush 18 into-a final position where a fiat side ofhex head 'lll will-be disposed in parallelism with wall 22''of-'reeess-- 2| b'ecause the forces setup by retation of-the wheel will 'cause the blades" to Work screws-I8 into the relationship shown in Figures 2 and 35 Screws I8 arepreferably designed, however, so that the faces of-socket 23 and hex head) are disposed in registry, as seen'in Figure 3; with'the result that therelationshipof the surfaces of hexhead |9-to wall 22 of blade B may be determ-ined by merely glancingat socket 23. Also, if a-wrench-=of; thetype-shown in dotted lines in Figure3 is; used, the relationship of the parts will i be f directly indicated by-th e position of the=w re3 ch'-handle:

If-fhowever; theheads of screws- !8 are sodimensioned as to seat in the bottoms of recesses 2 l -wh'emthey are turnedhomeit is unnecessary totake" any p artigzular precaution in installing the bladesbecause screws 18 are thus automatically-stopped in approximately proper position andwil-l-assumeproperposition when the wheel isstarted;

seeninthedrawin s, whenthe screws are turned-home'a' clearance exists between their shoulders and the parts of blades B defining recesses-Zl; Although-a particularvformof locking assembly has been illustrated, it is to -be-understood that other forms of locking devices, which themselves are locked by the blades, may be used without departing from the spirit of this invention. For instance, instead of using screws l8, simple pins, having formations at their ends for interlocking engagement with the blades whenthe latter are slid outwardly, may be used if desired. Moreover, hex head l9 may be made with more or less than six sides if desired. Forinstance, square headed screws may be used if desired.

Referring now to Figure 4, each blade B is provided with two recesses 2| in its base and it is therefore symmetrical in form. The base of the blade also may or may not be cored out, as at 24. With the wheel rotating in the direction indicated in Figure 2, the abrasive is picked up by and discharged from the counter-clockwise surfaces IB of blades B. By reason of the symmetrical design of blades B it is possible to remove the blades when they have become partially worn and reverse them end-for-end and thereby bring a new propelling surface into cooperation with the abrasive. The worn surface is accordingly placed on the clockwise side of each blade. When the new surface has become worn the blades are of course discarded.

If an uncored blade is employed, it is to be understood that a single recess 2|, located mid-way between the ends of the blade, maybe used. Also, two screws 18 may be employed to hold each blade of the present invention in place, but it has been found that one screw is adequate, and the term a screw or a securing device as employed in the appended claims is intended to embrace the use of one or more screws It or their equivalents.

As seen in Figures 1, and 6, feeding device F comprises a cylindrical member 26 having an abrasive discharge opening 21 and a plurality of external teeth having faces- 29 and 3|. Cylindrical member 26 is supported for adjustable rocking movement about the axis of the rotor upon a support S. Cylindrical member 26 is provided with a pair of studs 33', which project through a pair. of arcuately-shaped openings 34 provided in support S. A pair of nuts 35 are threaded on studs 33 and are operable to clamp feed device F to support S in any desired adjusted position, for varying the direction of discharge from the wheel.

Support S is provided with a spout portion 31 through which the abrasive may be admitted to the wheel and the abrasive fed through the spout is introduced into the center of 'a hollow impeller 38 having a plurality of blades 39. The forward face of each impeller blade 39 is concave in transverse section, and by reference to Figure 5, it is seen that each impeller blade inclines outwardly and rearwardly with respect to the direction of rotation of the rotor.

The impeller is provided with a base portion 4| which is realeasably clamped to the end of the rotor by means of a cap screw 42 or the like. The impeller is preferably, assembled in the machine so that each impeller blade is advanced a predetermined degree with respect to its propeller blade B. The right-hand side wall of member 25 (Figure 6) is provided withnotches (not shown) for allowing the impeller to be removed there from.

It has been found that when a particle of abrasive leaves the tip of an abrasive propelling blade its direction is determined by the respective magnitudes of its radial outward velocity component and its tangential velocity component.

I have'found that .by inclining the blades of the impeller rearwardly, so as to diminish the tangential component and simultaneously'increase the radial component, it is possible to make the abrasive discharge through opening 21 in container 26 to take the general path indicated by the arrows45 in Figure 5. The abrasive discharged through opening 21 in this manner assumes a more concentrated stream. The abrasive is then picked up by the inner ends of blades B passing;closely'adjacent opening 21 and is smoothly and continuously accelerated until it reaches; the blade tips, where it is discharged downwardly in the approximate direction indicated by the arrows '41. If it is desired to make the machine discharge in a direction other than that shown, nuts 35 may be loosened and cage 26 rocked in the proper direction to effect the de-' cation of opening 21; the speed of the wheel;

and the length of the blades, it is apparent that confining or concentrating the angular range .over which admission or pick-up occurs will simultaneously limit or reduce the angular region over which discharge from the blade tips occurs. It is impractical to achieve this result by reducing the circumferential dimension of opening 21' because to do so would seriously reduce the capacity of the machine.

It has been found that inabrading machines of this character, especially when large quantities of abrasive are fed thereto (from 15 to 25 thousand pounds per hour), a considerable portion of the abrasive is struck by the inner surfaces 48 of the blades, with the result that it rebounds back against the exterior wall of container 26. This rebounding abrasive, when containers having smooth exterior walls are used, is

reboundedoff the container and back into the path of the inner'ends of blades B at points angularly remote from opening 21, with the result that the discharge point of such rebounding abrasive occurs a considerable distance from the discharge point of the main body of the blades B along with the main bodyof the abrasive discharge. 3

Although I have for sake of providing a com pact assembly, provided the rebound teeth directly on the outside of conduit 26, it is to be understood that if desired, particularly if a plain feed pipe with no impeller is used, the rebound teeth may be formed in a separate member or members without departing from the spirit of my invention.

It is apparent that by inclining the imp'eua blades rearwardly so as to obtain a more nearly radial discharge of the abrasive through opening 27, and by providing the exterior of casing 26 with teeth, the concentration of the discharge of abrasive from the machine is greatlyimproved. In some installations it may not be necessary to have an extremely narrowband of abrasive and in such case it will only be necessary to employ.

one of these features,-;and the appended claims.

7.? are; therefore; intendedv to; .eoverthe; two leatures eithers'singly or in: combinatiom Inihe; presentxinstance, the impeller-wanes-are;

equal ;in;-,numb.er:-to;1 and; arezadvancediwithr re-. spect to theiripropeller; blades :B, with the me:

suit *that a a concentration; ofithe stream emittedj through opening 1-2-1 occurs-,eachgtin'ie a; bladeeB;

om sinto abrasive :pickjip position; with the ;re=- suit t a th .;dis haree ncentrating:action;is

urther i nhan e a In: Fi re; .8 an ifl-l hav illus rated modified forms-of blades that maybe used with-the machine thatahas j ust -,been';-described.. In :these figures itheblades are generally the same in for as those: shown: in Figures; 1 6' inclusive 'and therefore likereference charaetershave been;em-- played-to designate corresponding parts through out the several vviews. I

Figure :2 the p op n s r e 'o b are of-corrugatedrform so as=,to provide a pine rality. of valleys 55; It has been found that when-a blade ofthis character is, employed, theabrasive;,-jwhich is'introduced on the inner ends of .the blades; is-oausedto'take a plurality of definite paths outwardly-moreover; with the re-' sultthat uniform-distribution of the abrasive is-mai-ntained until it'leaves the-tips of the blades, Avoidance of localized wear is accordingly achieved.

In tzliiigurefl, the-valleys 55 on one. surface. are aligned with the valleys 55 on the other surface otthabl-ade with :theg'esult that the bladeis of non-uniform. section and. accordingly it; may be hardened at, somepoints more than others, .duriaotura nothe act r w ch. in-.

life of thiszbladeeover the ordinaryf erer t form of blade B which is :provided with; a. transversely corrugated abrasive propelling; surface-;5B.- In.v thisformaofithe invention, as.

the abrasive travels; outwardly" over thecorhea-tr contacts the blade surface a limited-numbenof times, before it is discharged 'fromthe -bladetip,

videdwithtransverse corrugations that lie. flush with tor. project slightly abovehthe outwardly extending corrugations so as'to confine theiabrae siv ntod i nite outwardpaths and .yetto caus itflto strike the blade a limited'number'of times as it travels outwardly,

In figures '1 0'an.d' 11 I haveshown a, modified form of blade'B wherein the blade isprovided with a; flat abrasive propellingsurface 6! The blade of this and abevelled inner edge 62. formof the invention is irreversible and hence is provided=with only one side flange 63 which, as-

seen inF-igurell, provides aninclined abrasive guiding wall; Thablade is -also provided adja-- urfacelit2 only strikes the a tops of the corrugations;- and 1in;v-iew of-= -the fact-that'-it only 8*; cents theajunctioni of: ab asiyei; propellin sure facejfilandxtheqbaseeofgtheg b ade withza; long-l1 tudinal, groove-:6 41fo thezburpose of, provid nsi' definite abrasive :confining. or guiding-wall so; as to prevent abrasive from; abrading dovetail groove forming plates I 2.

With blades B 'installed in the wheel so as to rotate in the direction indicated in-Figure-lO,

it issapparent that as theabrasive is discharged from opening 21 in cage 26; the abrasive ribbon will be sharply cut-:off; That is, there will :be

an abrupt break intheabrasive-ribbonas-allof the, abrasive preceding the break-will travel out-t wardly over propelling surfacefi-l and the succeeding'part of the ribbon-will not contact theblade;

atall byreason of the-fact that wall 62 -iscut away sufliciently so that'it moves away or re.-

cedestoo. rapidly for .the outwardly moving abra sive to strike it.

In- Figure 12 I have illustrated a-rblade similar to that shown in, Figures 10 and 11, but in this form of the invention the blade is provided with a slightly-. bevelled inner end 65 and. a similarlzy bevelledouter end-61.: In view-of the fact that; this formof blade is ymmetrical itmay be;-1'8-.-

' versed in the same manner as. the blades-shown riace-bladeASJth increasein area-.obr

in Figures 1, 2 and. 3. Although the bevel of the inner and outer ends-ofthe blades shown in Figure 10 are notfveryi great, it has been found that with-(the usual. speed of: the abrasiveissuing from slot, 2;lin. the, impeller cage. the abrasive travelsonly. approximately ofan inch while the blade is, traveling through. the;-

angle defined by thesinner Lends hithe -blades, and

therefore it 1 is 10 13., necessary to bevel thegbl'adeo parts to this extent in order to prevent theabra sive from striking theabevelled face.-

In Figures -13 and 14;]; have-illustrated a modi-- fled form ofymachinew-hereinthe impeller'cage is supported foradjustment in a different manner. In this form of the invention I have-shown a housing as being associated with the machine because certain parts of .the mechanism are attached thereto.

Therotor is here-enclosed in a housing H having an inner liner -'H. As seeninFigures 13-and 14, support Si is of; somewhat different-form than that shown in; Figured and iti'is provided a yoke member 79, which is.in;;turn slotted and held -in place on the-machine by a pair of headed stud members 81.

By looseningscrew:18"yoke: member 19 may be slipped out from underthe heads of studs 81 and the closure- Hrremoved: A screw driver may then be employed "to remove screws II so as to allow plate I2 to be removedfrom the rotor for servicing and" the like. Also, opening 76 provides a convenient opening through which the condition of the blades may be observed.

Secured to the rear face support S is an arcuately-shaped'stop plate 82 having an arcuate slot 83ftherein'. Plate 82 is detachably clamped to support S by means of "a stud 84, which is fastened lnsupportS a nut-85 and a collar 86;

r 9 The ends of stop plates 82 cooperate with the cylindrical portions of nuts 35 in order to maintain cage 33 in proper angular relationship in the machine.

For instance, it has been found that the machine may be adjusted for a certain type of abrasive and maintained in this adjustment so long as the abrasive and the conditions under which the machine is used remain unchanged. When cage 26 is placed in this adjusted position, nut 85 is tightened and maintains stop plate 82 in a position determined by nuts 35. Therefore, when nuts 35 are removed and cage 26 replaced by a new cage, the cage must be installed in the machine in the correct angular relationship as nut 35, when they are threaded on the studs of the new cage engage stop plate 82 and bring the cage into correct position. In order to indicate the angular position in which the cage is rotated, I preferably provide flange 72 with indicia 8'! which cooperate with a righthand nut 35 (Figure 13) to indicate the position at a glance.

Although it is preferably to employ the blade assembly with a rotor having but a single disc to which plates 12 are secured, the invention is clearly applicable to rotors having two discs as the guideway and/or the blade locking assembly may be duplicated on each disc.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In an abrading apparatus, an abrasive propelling rotor mounted for rotation and providing a central abrasive admitting space, a feed device for introducing abrasive into said space, a stationarily mounted support having at least one arcuately shaped aperture, said feeding device having at least one securing device projecting through said arcuate aperture and operable to clamp said feeding device in a plurality of difierent positions upon said support, and a stop member releasably clamped to said support and having a portion cooperating with said securing device for insuring proper assembly of said feeding device upon said support, thereby permitting said feeding device to be removed and replaced without disturbing the adjustment thereof.

2. The abrading apparatus described in claim 1, wherein said securing device comprises a stud member fastened to said feeding device and a nut threaded thereon and engaging said support and said stop member.

3. The abrading apparatus described in claim 1, wherein said stop member comprises a member engageable with said securing device and having means securing it to said support for movement into a plurality of adjusted positions corresponding to the adjusted positions of said feeding device.

4. In an abrading apparatus, an abrasive propelling rotor mounted for rotation and providing a central abrasive admitting space, a feed device for introducing abrasive into said space. means mounting said feed device for rocking movement into a plurality of adjusted angular positions about the axis of said rotor on a stationary support, means for securing said feed device in one of a plurality of adjusted angular positions with respect to said support, and means for compelling assembly of said parts in a predetermined relationship, said last-named means comprising an element having means for releasably clamping it to said support in a plurality of angular adjusted positions with respect to said support, said element being movable through a range of movement substantially equal to the range of movement of said feed device with respect to said support.

5. In an abrading apparatus, a rotor having a plurality of outwardly extending abrasive propelling blades mounted thereon, said blades terminating short of the axis of said rotor to define an abrasive admitting space, said blades being operable to pick up' and propel abrasive admitted at a predetermined feeding zone in said abrasive admitting space, and stationarily supported means disposed in said abrasive admitting space for rebounding back toward said feeding zone any abrasive that may be improperly picked up by the inner ends of said blades, said means comprising a member having a plurality of angularly disposed rebound surfaces provided thereon and located adjacent the path of rotation of the inner ends of said blades substantially equi-distant from the axis of rotation of said rotor, said surfaces each being inclined at an obtuse angle with respect to a radial line intersecting said surface, said obtuse angles facing rearwardly with respect to the direction of rotation of said rotor.

6. The abrading apparatus defined in claim 5, wherein a generally cylindrical abrasive feeding device is disposed in said abrasive feeding space and said rebound surfaces are provided on said feeding device.

7. The abrading apparatus defined in claim 5 wherein a generally cylindrical abrasive feeding device is disposed in said abrasive feeding space and said rebound surfaces are provided on said feeding device, said abrasive feeding device containing a rotatable impeller having blades which incline outwardly and rearwardly with respect to the direction of rotation of said rotor.

WALTER L. KEEFER.

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

UNITED STATES PATENTS Number Name Date 391,971 House at al Oct. 30, 1888 469,642 Nehr Feb. 23, 1892 1,052,291 Smoot Feb. 4, 1913 1,535,417 Huff Apr. 28, 1925 1,789,874 Lilly Jan. 20, 1931 1,918,653 Martin July 18, 1933 1,953,566 Peik Apr. 3, 1934 2,119,813 Keefer June 7, 1938 FOREIGN PATENTS Number Country Date 442,539 Great Britain Feb. 10, 1936 512,269 Germany Nov. 8, 1930 519,837 Germany Mar. 5, 1931 784, 30 France s M y 1 3?

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