US2116153A - Abrading apparatus - Google Patents

Description

May 3, 1938. w. I KEEFER 2,116,153

ABRADING AFPARATUS. y

Fi 1ed sept. 2,' 1937 s sheets-sheet 1 55,43 SL/WM SIMM/1f- Ma'y 3, 1938. w. L. KEEFER ABRADING APPARATUS Filed Sept. 2, 1937 5 Sheets-Sheet 2 May 3, 1938. l w. l... KEA-:FER A 2,115,153 ABRADING APPARATUS Filed sept. e, 1957 s shets-sheet s Patentedl May 3, 1938 `I UNITED STATES PATENT ()FFICE Pangborn lCorporation, corporation of Maryland Hagerstown, Md., a

Application September 2, 1937, Serial No. 162,214

26 Claims.

'Ihe present invention relatesto abrading ap paratus, and more particularly to apparatus known in the trade as blast cleaning machines embodying means for projecting a stream ofabrasive in thel form of sand or steel abrasive wherein the abrasive is admitted at low velocity4 15 over the inner ends. of the blades and is continuously accelerated to the blade tips or whether they are wheels. embodying batter blades where the entire abrading velocity is imparted to the abrasive by a single instantaneous impact therewith. Y

Although the slidervtype machines in commercial use today represent a great advance in the art over the machines heretofore in use they do not possess all oi' the operating characteristics desired and fall considerably short of the ideal machine which would pick the abrasive up without shock and gradually Vmove it out to the periphery of the rotor without sliding it and then discharge it without wearing influence upon any part of the machine.

It is accordingly a primary object of this invention to provide an abrasiveA throwing wheel which does not employ any blades whatsoever and more nearly approaches the ideal abrading apparatus than anything heretofore proposed.

It is another object to devise a centrifugal abrading machine wherein the abrasive is admitted near the axis of rotation, moves outwardly with substantially no propelling influence and then is released from the wheel substantially at the peripheral speed thereof without having a batting or other impacting action applied thereto. It is a further important object to design a wheelfor mechanically vthrowing abrasive which employs no blades whatsoever, retains a prede- .ermlned quantityof abrasive in the wheel at all times and discharges a predetermined `quantity at each rotation of-'the wheel and imparts a high abrading velocity tothe abrasive.

' My invention also aims to provide an abrasive and feeding and propelling assembly that may be used in combination with centrifugal bladed rotors for imparting directional control thereto.

Further objects of the invention will become apparent as the accompanying specication proceeds in connection with the annexed drawingsand from the appended claims.

In the drawings:

Figure 1 is a longitudinal sectional view of lan apparatus embodying the invention.

,Figure 2-is a view looking from the right hand side of the machine shown in Figure l and parts have been 'broken away in order to more clearly show the structure involved.

Figure 3 is a sectional view taken on the line 10 3 3 o f Figure 2 showing the parts as .they appear when viewed in the direction of the arrows.

Figure 4 isa fragmental sectional view of a part of wheel shown in Figure 1 and illustrates one of the abrasive discharge openings. 15

Figure l5 is an elevational view of the feed chamber of the machine of Figure 1, and illustrates the abrasive dellector.

Figure 6 is a. longitudinal sectional view similar to Figure l but illustrates a modiiled form of the invention.

Figure 7 is an elevational view looking from the right handside o f Figure 6 and parts have been broken away in order to more clearly show the structure involved.

Figure 8 is a fragmental sectional view of the s machine shown in Figures 6 and 'l and illustrates the rotatable disc employed to deflect lor dislodge the abrasive from the inner surface of the wheel.

Figure 9 is a longitudinal sectional view Vthrough a further modified form oi' wheell also forming part of the invention.

Figure 10 is a partial elevational view of the machine shown in Figure 9 and illustrates it as 35 it appears when viewed from the right hand side of that ligure.

Figure 11 is a fragmental partial sectional view of machine shown in Figures 9 and 10 and shows the deecting members. 4-0

Figure 12 is a face view of a bladed rotor-embodying the abrasive propelling mechanism of the invention.

Figure 13 is 'a longitudinal sectional view through the wheel shown in Figure ,12, and in this form the defiecting disc has been only diagrammatically illustrated. p

Figure 14 is an enlarged sectional view of the feeding mechanism employed inthe machine of Figures 12 and 13 andl illustrates the manner in 50 which the abrasive is introduced into the abrasive chamber and discharged therefrom.

With continued reference to the .drawinga whereinlike reference characters have been employed throughout the several views thereof to manner.

designate like parts, and with particular reference to Figures 1 to 5, inclusive, the machine broadly comprises a hollow rotatable member upon whose inner surface the abrasive is centrifugally built up and the layer of abrasive is automatically discharged from the member at a predetermined point in rotation by means of a defiector which directly engages the layer of abrasive deposited within said member.

The hollow member just referred to includes a head I0, which is mounted on a shaft II. The latter is journaled for rotation in any suitable As seen in Figure 1, head I is hollowed out from one side and is provided with an abrasive accelerating groove I2 at its periphery which merges with a radial face I3 of the rotor. Head IIJ is also provided with a flanged portion Il in which a plurality of abrasive discharge openings I5 are provided.

In order to provide for wear oi the parts and make it possible to replace certain parts of the machine Without replacing the entire rotor, a wear bushing I1 is disposed in each opening I5 and as seen in Figures 1 and 4, each wear bushing I1 is provided with a portion extending into opening I5 and is provided with an inclined rear wall I8 for a purpose that will presently appear.

A disc 2| is preferably secured to the end of the rotor for preventing inadvertent escape of abrasive,.but it may be omitted if desired.

'I'he abrasive may be admitted to the interior of the rotor in any suitable manner, but I preferably employ a generally cone shaped member 22 having a funnel portion 23 and which is mounted on a shaft 24. Shaft 24 is journaled in a bearing 25 provided on a bracket 26 and the latter is secured to a stationary base 21.

Feed chamber 22 is accordingly mounted for rocking movement about the axis of rotation of the rotor and it is provided with a handle 28 for manipulating it into its adjusted position. A set screw 29 is threaded into bracket 26 for locking shaft 24 in its proper adjusted position.

Assuming that shaft II is driven by any suitable prime mover at a speed of approximately 2500 revolutions per minute, and abrasive is admitted to spout 23, it will travel at relatively low velocity until it strikes the mass of abrasive in the abrasive acceleration groove I2, where it will be picked up and rapidly attain the peripheral speed of the rotor. In view of the fact that when the Wheel is in operation groove I2 is filled with abrasive, theaccelerating action imparted to the abrasive is taken by the abrasive itself that is accumulated in the groove, and accordingly Wear of the acceleration groove walls is minimized.

Assuming that the wheel is rotating as just de-I scribed, the abrasive will fill up groove I2 and then spill over onto the internal surface 3| of the rotor. The parts are so designed, and rotor surface 3| is of suilicient Width so that as the abrasive builds up it will assume the form of a cone with its inner surface inclined at an angle equal to the angle of repose of the particular abrasive, and during normal operation will not spill into openings I5 unless it is acted upon by the defiector, which will now be described.

One form of defiector means that may be used to dislodge abrasive at a predetermined point in the revolution of the rotor, is shown in Figures 3 and 5, and it consists of acomparatively thin' blade 33 made from any suitable heat resistant material, such as tungsten alloy steel. y

Deflector blade 33 may be stationarily supported in any desired manner but in the present instance I have shown it as being supported by a pair of bosses 34 on member 22 by means of a pair of screws 35.

Deector 33 is curved as seen in Figure 2, and its outer edge lies in close proximity to the inner surface of the rotor, with the result that when the wheel is rotated the layer of abrasive lying on surface 3| will be continuously acted upon by the defiector and deflected into openings I5. f

Referring to Figure 3, with the Wheel rotating in the direction indicated by the arrow, an abrasive particle is indicated at 38 as just contacting blade 33. This particle, prior to engagement thereof with the defiector possessed a velocity Vr or a velocity equal to the peripheral speed of the rotor.

Upon engagement of the particle with defiector 33, it assumes a velocity having an axial component Vd and the two combined give a resultant velocity Vx. Therefore, there is continuously deposited on the inner surface 3| a layer of abrasive and this layer of abrasive is being continuously discharged from the wheel at one point by reason of defiector 33 engaging it and causing it to be pushed axially into registry with the discharge openings. Y

In view of the fact that the abrasive lying centrifugally on surface 3| is rotating atthe peripheral speed of the wheel, and as this speed is selected to correspond to the desired abrasive discharge speed, it is unnecessary to impart a blade action upon the abrasive as it is spilled through opening I5 in order to impart an abrading velocity thereto. Wall I8 of opening I5 is accordingly inclined as shown in Figure 4 in order to avoid an impelling influence being given to the abrasive as it passes through opening I5. However, if desired, the combination of the rim discharge and blade action may be used, and in a succeeding form of the invention I have shown a machine of just this character.

In view of the fact that the point of discharge of the abrasive is dependent upon the angular position of defiector 33, the wheel may be caused to fire in any direction by loosening screw 29 and rocking the feed chamber 22 in the proper direction to cause the machine to discharge in the desired direction. As a matter of fact, if it is desired to have the machine discharge upwardly the feed chamber may be located in the position shown in the drawings, but the defiector may be secured thereto at a point 180 degrees removed from the location shown in order to make the Wheel fire upwardly rather than downwardly. If after the Wheel is in use it is found that the spray angle or the width of the centrifugal blast is too narrow, the defiector may be moved closer to the Wheel so as to deflect'a greater depth of abrasive for each revolution, or the defiector may be longer so as to deflect a greater body of abrasive or a flange may be provided on the defiector to dislodge a greater quantity of abrasive. To this end member 33 may be adjustably mounted on chamber 22 or any other stationary part of the machine.

If desired, however, two deectors may be placed in series at different angular points so as to increase the width of the abrasive spray angle.

.Although I have shown a particular feed chamber for introducing the abrasive in the rotor, it is to be understood that if desired various other forms of abrasive admitting means may be used. For instance, abrasive may be admitted at the center of a pair of grooved rotating discs and be l to lock it in place.

allowed to trickle -outwardly thereover and gradually4 accelerated.

Taking up the formrof invention illustrated in Figures 6, 7 and 8, the major differences between this device and the first described form oi the invention reside in the use of a wheel having passages for gradually accelerating abrasive as it moves outwardly and also, a rotatable 4disc which is employed to deflect the abrasive at a predetermined point in rotation. In this form of the invention a rotor 4D is mounted on shaft 4I and is provided with a pair of abrasive accelerating flanges and 43, an abrasive acceleration groove 44 and an abrasive supporting or deposit surface 45.

In this form of the invention feed chamber 46 is similar to that previously described with the exception that it provides a pair of annular grooves 41 and 48 which cooperate with flanges 42 and 43 of rotor 40 to dene a tortuous passage. Thereforel when the abrasive introduced in chamber 46 rstencounter's ilange 42 it is partially accelerated, fills up to the angle of repose and 'spills off the edge into groove 41 where it is deilected onto flange 43. Flange 43 being further. from the axis of rotation is rotating at a greater peripheral speed than ange 42, the abrasive accordingly receives further acceleratitm when'it strikes this viiange. 'I'he abrasive then spills oif flange 43 into the acceleration groove, which, being located still further from the axis of rotation further accelerates the abrasive.-

The feed chamber is mounted on a shaft i5 as before, which is journaled in a bracket 5l carried by a base 52. An operating handle 53 is employed to rock the feed chamber into vthe proper angular position and the set screw 54 is employed In this form of the invention a disc 55 cooperates with the rotor to spill the abrasive over the side edge of the rotor and it is journaled in a bearing 51 carried by an arm 58 which, as shown, is an integral part of the feed chamber, with the result that the direction of discharge may be controlled by rocking the feed chamber.

friction of the abrasive upon the wheel is scient to Acause it to undergo independent rotation.

Disc 56 may also, ii desired, be adjustably supported so as to dispose its axis at any suitable inclination tothe axis of the wheel. l

fBy reason of the fact that the peripheral speed of disc 55 is substantially equal to the peripheral speed oi' rotor lill, it is apparent that it will undergo a minimum abrading action during operation, and at the same time smoothly spills the abrasive over the side or discharge edge 55 of the rotor.

Although l have illustrated disc 5t as lying at a predetermined angle with respect to the axis of rotation of rotor du, it is to be understood that vthis angle may be increased or the disc axis inclined so as to dispose the disc in other directions for discharging the. abrasive from the wheel, depending upon the particular work being handled, the abrasive used, and other inuential factors.

It is accordingly seen that with this forni oi l 'of invention described, the abrasive discharge isdiscontinuous in the sense that it is successively discharged through openings l5. If desired surrigidly carried by shaft di. f

ltace 45 and/or edge 59 may be formed in a separate removable and replaceable wear element'.

It will be understood that a disc deiiector like that used in the form or the-invention illustrated l in Figures 6, 7 and 8 may be used instead oi' the '.deector 33 in the form of the invention illustrated in Figures 1, 2 and 3.

= Referring now tu Figures 9 and'lo or the dra'wrim portion 82 to which is secured an end plate 83.

' In rim portion 62 there are provided a plurality of inserts 64 aiording a openings 65. v In this form oi.' the invention no acceleration groove is employed as the abrasive is dumped into a recess 66 provided in the rotor disc and builds up kon surface 61vwhere it isI deflected into discharge opening 65 by either a stationary deector member or a rotatable disc as described in connection with the first form ofthe invention.

In this form of the invention a cage is employed embodying a cone portion 63 which is secured to a hub portion 1l by a plurality of cap screws 12. Portion 1| is provided with a funnel portion I3 and it is secured to a hollow shaft 14 by means of a key 15 and a'set screw 1B. Shaft 14 is journaled in a support 18 and is provided with an operating handle 19. Shaft 14 is adjustably locked in xed position by nut and bolt assembly 8i which cooperates with an arcuate slot 82 in support 18', whereby the parts may be locked by tightening the nut and bolt iassembly.

Journaled in sleeve 14 is a shaft 53 to which is secured a handle t4 by means of a set screw 85. Handle i carries a detent 86 which cooperates with serrations il formed on`a downward extension 58 of handle l5. This device is similar to that described in connection with the drst form of the invention, the abrasive being admitted in chamber 5d and piling up against the inner surface lil of the rotor and being dislodged ordeplurality of discharge fiected through opening 55 by means oi a sta- Aithough wheel 55 may if desired be driven by a- -separate prime mover, it has been found that the tionarily supported deflector either oi the stationary plough or shoe type shown in Figure 5 or vdischarge oi the machine or to compensate for' t wear by loosening the stud and nut assemblies.

In this ioirn of theinvention there is employed a primary deector blade i5 which acts upon the abrasive before blade iid comes into play and as the initial contact 'is oi greatest magnitude the primary blade takes the most wear. Accordingly in order to `make blade 5d quickly and easily' ad justable to compensate for wear it is mounted for guided sliding movement in a recess in chamber 55 and projects outside chamber 55 adjacent the leading edge of blade lili. e

` Pivotally secured to blade-55 by means of a pin 5l is'a connecting link di, which in turn is connected by means oia crank pin 53 to a disc 5d face 5l and blade it will apply a secondary de' ecting action thereupon. When the outer end of bladev 55 has A.become worn through contact wardly into a new position. The parts have been position to effect the desired discharge of abrar illustrated as new and hence in Figure l lever 84 may be moved step by step through 180 before blade 90 is unfit for further service. Also, from time to time blade 88 may be adjusted outwardly to,c0mpensate for4 wear in the manner previously described.

In Figures 12, 13 and 14, I have shown a com-f bination ofa rim discharge abrasive throwing wheel used as the feeder for a bladed abrasive throwing wheel.

With continued reference to these figures, a V

rotor H0 mounted on a shaft IH is provided with a plurality of abrasive propelling blades l I2. The blades terminate short of the axis of revolution to define a central spaceand mounted in this space is a chamber H3 and it is preferably removable so that it may be taken out and replaced when it has become tooy worn for further service. A

. The abrasive is fed to the interior of member H3 by meansof a feed conduit H5. Journaled in conduit l I5 or in any other suitable manner is a shaft H6, carrying a spider H1 which in turn supports a disc H8. In this lforml of the invention abrasive is introduced through chute H5 and piles up to its angle of repose on the interior of member H3, and at a predetermined point in the rotation of the parts disc H9 defiects a layer of abrasive 'over the edge |2| of member H3 onto the inner ends or heels of the throwing blades. In view of the fact that the direction of discharge of the abrasive from member H3 is substantially tangential the abrasive is picked up by the inner ends of the blades with negligible impact.

may be controlled in a manner similar to that effected in the wheels previously described, name- 1y,` byadjusting angularly the point at which` the deector cooperates with the abrasive lying on the inner surface of member H3. Accordingly it is only necessary to adjust. spout, H5 and shaft H6 to locate disc H9 in the proper sive.

Although I have shown member H8 as being driven @synchronously with the rotor and feeding the abrasive over the inner ends of the blades, it may be independently driven and feed the abrasive over the side edges of the blades without departing from the spirit of my invention. Also, I have illustrated certain parts of the apparatus asbeing integrally formed with the rotor. but it is tobe understood that if desired separate replaceable wear elements may be provided.

In all of the forms of the invention ,the abrasive is deposited on lthe inner surface of the rotor and lbuilds up to its angle of repose and therefore the deector need apply but force enough to cause the abrasive to move to the discharge point. Therefore, the wear on the deflector is minimized.

The invention may be embodied in other specie forms without departing from the spirit or essential ,characteristics thereof. The present embodiment is therefore to be considered in-all r respects as illustrative and not restrictive, the

scope of the invention being indicated by theV claims are therefore intended to be embraced therein.

What is claim-:d and desired to be secured by United States'Letters Patent is:

4l. In an abrading apparatus, a structure mounted for rotation athigh speed, said structure providing a. generally annular surface facing toward 'the'axis of rotation of said structure, means for depositing abrasive upon said surface, and discharge means for dislodging the deposited abrasive from said surface at a predetermined point in the rotation of said structure for projecting said abrasive at an abrading velocity.

2. The abrading apparatus set forth in claim l, wherein said discharge means comprises a stationarily supported device for directly engaging the deposited abrasive and imparting an axial movement thereto.

3. The abrading apparatus set forth in claim 1, wherein said discharge means comprises a stationarily supported device mounted adjacent said structure and cooperating with said deposited abrasive, said device being lmovable into a plurality of angular positions with respect to the axis of saidl structure, whereby the direction of the discharge of abrasive from said structure may be varied at will.

4. In an abrading apparatus, a structure -mounted for rotation at high speed, said struc- 5. The abrading apparatus set forth in claim 4,

wherein said discharge means comprises an inclined deflector blade stationarily supported adjacent said structure and operable to engage and deflect said deposited abrasive axially over said one edge of said surface.

6. The abrading apparatus set forth in claim 4, wherein said discharge means comprises a rotatable member disposed adjacent said structure and operable to directly engage said deposited abrasive. 1 Y

A'7. In an abrading apparatus, a structure mounted for rotation at high speed and comprising a hollow member, means for depositing abrasive upon the inner surface of said member while the latter is rotating and abrasive discharge means for engaging and deiiecting said abrasive over one end of said member while the same is rotating for discharging said abrasive at an abrading velocity.

- 8. The abrading apparatus set forth in claim '7, wherein said first named means is operable to deposit abrasive upon said member at a point sufficiently remote from said one end of said member so that said abrasive will build up to its angle of repose adjacent to but short of said one end `of said member, whereby said abrasive will be discharged from said member only when it is engaged bysaid abrasive discharge means.

9. An abrading apparatus comprising a structure mounted for. rotation at high speed, said structure embodying a hollow lmember rotatable with said structure with its axes coincident to theA axis of rotation of said structure, said member having a plurality of discharge openings provided therein disposed in the same general plane of revolution, means for depositing abrasive upon Y rotating and allowing said abrasive to attain the 'dil dll

9,116,153 the inner surface -of said member ina region spaced vfrom said discharge openings. and means located within said member for engaging the layer of abrasive deposited within said member and moving it axially to said discharge'openings.

10. In Van abrading apparatus, a structure mounted for rotation at high speed, saidstructure providing an annular inwardly facing abrasive supporting surface terminating at one end in an abrasive discharge edge. means for depositing abrasive upon said surface while said structure is full peripheral speed of said inner surface, said abrasive being deposited upon said inner surface at a point spaced from said discharge edge and adapted to build up thereon to its angle 'of repose without spilling over said discharge edge, and a rotatable disc mounted adjacent said structure fordeilecting said deposited abrasive over said discharge edge and discharging it at an abrad- .ing velocity.

A11. The abrading apparatus set forth in claim 10, wherein saidV structure is provided with an abrasive acceleration groove adjacent said annular surface which is adapted to accumulate a body of abrasive when said structure is rotating.

12. 'I'he abrading apparatus set forth in claimv l0, wherein said structure is provided with means for accelerating the abrasive in stages before it is depositetl upon said annular surface, whereby said abrasive promptly attains the full peripheral speed of said structure upon contact therewith.

13. In an abrading apparatus, a structure mounted for rotation at high speed and having a plurality of abrasive propelling blades provided thereon, and means mounted adjacent the center of rotation of said structure for feeding a stream of abrasive over the edges of said blades for causing the abrasive to be picked up and-discharged by said blades in a predetermined direction, said means comprising 4a rotatable element providing an inwardly facing surface; means for feeding abrasive to said surface; and means for dedecting the abrasive accumulated on said surface into the path of rotation of said abrasive propelling blades.

1d. lin an abradingapparatus, arotor having a plurality of abrasive propelling blades terminating short of the axis of rotation to define a central abrasive admitting space, abrasive feeding means mounted in said space and rotating synchronously with said rotor providing an inwardly facing abrasive supporting surface, said surface having a discharge edge disposed between the inner ends of said blades, means for depositing abrasive upon saidsurface, and abrasive deflecting means for deecting the abrasive deposited on said surface over said discharge edge into' the path of rotation-of the inner ends of said blades.

l5. The abrading apparatus set forth in claim 14, wherein said abrasive deecting means comprises a disc .disposed within said abrasive feeding means and mounted for rotation about an` 'means for moving said deposited abrasive axially so as to discharge it from one edge of said surface when said abrasive attains a predetermined position in the rotation of said structure, said discharge means comprising a primary deflecting element and a secondary denecting element for en'glng the deposited abrasive, said primary deiiecting element having means for adjusting it toward and away from said generally cylindrical 17. In an abrading apparatus, a head structure mounted forV rotation and providing a generally annular surface facing toward lthe axis of rotation of said head structure, means for depositing abrasive upon said surface. and control means forv causing the deposited abrasive to discharge from'b r said surface at a predetermined pointin there-ff tation of said head at an abrading velocity.;

18. The apparatus set'forth in 17, wherej' in said control means comprises a tating about an axis inclined to theaxisoffsaid head structure and ico-operatingwiththe sive deposited on said annular surface.'u v 19.v In an abrading apparatus. 'a-fhead structure mounted for rotation and havingan [annular abrasive accelerating groove facing toward. the

axis of rotation of said head, means for depositingabrasive 'in said groove, said head structure also providing a generally annular, inwardly facing surface adjacent said groove and adapted to receive abrasive overflowing from said groove and control means for causing the discharge of abra-4 sive from said annular surface at a predetermined point in the rotation of said head structure.

2i). In anabrading apparatus, Aa rotor mounted for rotation at high speed and having a plurality of abrasive propelling Ablades provided thereon; a generally cylindrical rotating feed chamber mounted adjacent, the axis of rotation of said rotor; means for-feeding abrasive to said feed chamber for causing vit to centrifugally build up to its angle of repose on the inner surface of said feed chamber; and means for denecting the accumulated abrasive from said feed chamber intothe path of said abrasive propelling blades at a predetermined point in the rotation of said rotor', for causing the abrasive to be picked up and discharged by said blades rection. I

dl. lin an abradlng apparatus, a rotor mounted for rotation at high speed and having a plurality of abrasive propelling vblades provided thereon, said blades terminating short of the anis of rotation of said rotor to denne a central space; a generally cylindrical feed chamber secured 'to in a predetermined disaid rotor, and projecting into said central space, said feed chamber terminating at one end in a' discharge edge located adjacent the inner ends of said blades, means for feeding abrasive to said feed chamber, whereby it centrifugally accumulates on the inner wall thereof, and `means for' /dehecting the accumulated abrasive from said their side edges contiguoim to, one face thereof,.

and said feed chamber is secured to said structure with its discharge edge located between said structure and a plane normal to the axis of rotation of said rotor and disposed midway between the side comes of said abrasive propelling blades.

23. The abrading apparatus dedned in claim 2l.,

wherein the diameter of said feed chamber is approximately equal to the length of said blades.

24. In an abrading apparatus, a structure whereby the point in the rotation of said struc ture at which the abrasive is deected into the path ofrctation of said blades may be selectively varied.

25. In an abrading apparatus. a rotor having a`plurality of` abrasive propelling yblades provided thereon; arotatable element mounted adjacent the axis of rotation of said rotor and providing an inwardly facing abrasive accumulating surface; feeding means i'or supplying abrasive to said surface;- and a rotatable disc for deilecting the abrasive accumulated on said surface into the path of rotation of said abrasive propelling blades at a predetermined point in the rotation of said rotor for causing the abrasive to be picked up and discharged by said blades in a predetermined direction, said disc having a central opening, said feeding means being operable to discharge abrasive into said rotatable element through the central openingof said disc.

26. In anv abrading apparatus, a rotor having a plurality of abrasive propelling blades provided thereon, said blades terminating short of the axis of rotation of said rotor to define a central space; said rotor having in said central space an inwardly facing abrasive accumulating annular ledge rotatable synchronously with said rotor and having a discharge edge located adjacent the path of rotation of the inner ends of said blades, and between the planes of rotation defined by the side edges of said blades; means for depositi ing abrasive upon said ledge, and means for delfleeting the accumulated abrasive from said ledge over the discharge edge thereof and onto the inner ends of said blades at a predetermined point in the rotation of said rotor, for causing said abrasive to be discharged in a predetermined direction from said rotor.

WALTER L. man.

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