US2246522A - Abrading apparatus - Google Patents

Description

June 24, 1941. w. L KEEPER ,522

ABRADING APPARATUS Filed March 10/1958 5 Sheets-Sheet 1 June 24, 1941. w. L. KEEFER ABRADING 'APBARATUS Filed March 10, 1958 3 Sheets-Sheet 2 Wa/fer Z Keefe)" W. L. KEEFER ABRADING APPARATU 5 Filed March 10, 1938 June 24, 1941.

3 Sheets-Sheet 3 I III/Il/I 41 WEI/fer L Keefer ?atented .iune 24, 1941 annanmo mana'rus "Walter L. Keefer, Hagerstown, Md., assignor to Pangborn Corporation, Hagerstown, Md., a corporation of Maryland Application March 10, 1938; Serial No. 195,138

' 15 Claims. (Cl. 51-9) This invention relates to abrading apparatus and is more particularly concerned with machines embodying a bladed rotor forpropelling abrasive at high velocities against, articles to be cleaned. r

-Mach'ines are in commercial use today r em-' bodying bladed rotors and although they represent an advance in the art over the machines heretofore in use they leave much to be desired from the standpoint of wear of variousessentie! operating parts. For instance, directional control is attained in those machines through the use of a central stationary feed cage having a feed slot therein through which abrasive is discharged onto the inner ends of the blades by ing partially broken away and the spout in phantom lines to more clearly illustrate the structure involved; I

Figure 2A is a sectional view taken on the line iA- -lA'of Figure 2;

Figure 3 is an enlarged front elevation of the cup-shaped member employed in the device means of a rotatable impeller located in the feed cage. These impellers and cages wear out comparatively rapidly under the action of the abrasive and must be removed and replaced by new parts, which entails the expense of thenew parts and. also the loss of operating time that must be incurred while the machine is down for servicing.

In my copending application Serial No. 162,214,

filed September 2, 1937, now Patent No. 2,116,153, dated May 3, 1938, I have shown a bladed centrifugal abrading wheel which possesses directional control and yet which does not employ an impeller or a slotted stationary feed cage, and it is the major object of this invention to improve and generally refine the machine of my prior application. v

A further object is to provide abladed centrifu gal abrading rotor with a rotatable abrasive accum lating chamber and a stationary helicaldeflee ing member for deflecting the abrasive from the chamber onto the blades.

It is another object to provide a combined abrasive feeder and deflecting assembly for cooperation with the rotatable feed chamber of a bladed centrifugal abrading rotor.

My invention further aims to provide a nov abrasive propelling blade having a propelling surface so formed as to cause the abrasive fed thereshown in Figures 1 and 2;

Figure 4 is a section taken on the line H of Figure 3, looking in the direction of the arrows:

Figure 5 is an enlarged front elevation of the deflector assembly employed in the apparatus of Figures 1 and 2;

Figure 6 is aside elevation of the structure shown in Figure 5; v

Figure I is an enlarged fragmental longitudinal view of the structure shown in Figure 1 taken partly in section, and illustrating an abrasive guard element cooperating therewith, which element also forms part of the invention:

Figure 8 is a section taken along the line 8----4 of Figure 7, lookingin the direction of the an I'OWS;

Figure '9 is a top plan view of the abrasive guard elements shown in Figure 8:

Figure 10 is a view similar to Figure 1, but shows a somewhat modified form of splash de flector.

i The present invention, generally speaking. is directed to a mechanism for centrifugal abrading which includes a rotor; a feed spout, and interposed transfer mechanism, the latter preferably comprising a cup-shaped member rotating at .substantially the same speed as the rotor, and a deflector element, normally stationary but adiustable, which effects the discharge of a concentrated stream of abrasive over the open edge of the cup-shaped member at a predetermined angular position.

With continued reference to the drawings.

J wherein like reference characters have been emplayed .to designate like parts throughout the several views thereof. and referring particularly .to Figures 1 to Q3, inclusive. the rotor which includes the blade assembly may assume any de sired form, but I have shown a rotor R secured to the hub portion ll of a shaft II by means of a plurality of screws (not shown).

of sector-shaped plates II aredetachably secured to the face of rotor R by a screws l3. s

As seen more in detail in Figure 2A, plates I! are spaced apart on the rotor and their neighboring edges are bevelled as at M so that they plurality of A plurality .that will presently appear.

cooperate with the face of the rotor to define outwardly extending dovetail-shaped guideways. Blades B are provided with dove-tailed shaped bases liwhich slidably cooperate with the guideways and they are locked against outward movement by a plurality of detachable keys Hi which are provided with lug portions l1. As seen in Figure 2, keys is slidably fit into correspondingly shaped openings i8 provided in plates i2.

Each blade B is provided with an abrasive propelling face 2| and an abrasive guiding flange 22 for preventing the abrasive from escaping over the free edge of the blade during operation. As seen in Figure 1, each blade is-provided with a shoulder 23 so that when the blade is moved inwardly slightly from the position shown, key it may be moved to the right and removed from the rotor and blades B may then be freely slid outwardly and removed from the apparatus for replacement. Therefore, when the blades are in place and are centrifugally urged outward during operation, shoulders 23 positively prevent the keys from being displaced.

The transfer mechanism which receives abrasive from the feed spout and delivers it onto the inner ends of the blades will now be described. Rotor R. is provided with a central opening 25 and seating therein is the base of what may be called a cup-shaped member or cup. The cup is provided with a closed bottom 26 and it is secured to hub in by means of a cap screw 27. As seen in Figures 1, 3 and 4, the cup is provided with an axially extending flange 28 which terminates slightly short of a plane passing through the medial portion of the blade, for a purpose Flange 28 is provided with a plurality of axially extending grooves 29 for the purpose of causing a stationary layer of abrasive to remain in engagement with the flange at all times during operation. Also, a plurality of webs 3| are provided in the bottom of the cup for the purpose of strengthening it.

The cup is also provided with a pair of annular grooves 32 which function to assist the abrasive in lying centrifugally on the flange at its angle of repose, and for preventing it from prematurely discharging from the cup. Flange 28 terminates in what may be termed a discharge edge 33 over which the abrasive is discharged Onto the inner ends of the blades. Abrasive is supplied to the cup by means of a feed spout 35 which is stationarily supported in a permanent position by any suitable means (not shown). Spout 35 is provided with an inclined portion 38 which terminates in a cylindrical portion 31.

Portion 31 of the feed spout projects into the deflector assembly D, which is a part of the transfer mechanism and is provided with an inner generally cone-shaped opening 33 and a cylindrical throat 39. Throat 39 is of a diam- .eter slightly greater than terminal portion 31 of the spout, with the result that they flt sufllciently closely to prevent abrasive leakage between the parts, and yet the deflector assembly may beadjusted to vary the direction of discharge from the mechanism in a manner .to be hereinafter pointed out The deflector assem bly is, accordingly, provided with a flaring mouth through which the abrasive is discharged to the interior of the cup.

The deflector assembly is provided with a flange 4"l which is in turn secured to the flange 42 of/a support 43 by means of a pair of nut and *bolt assemblies 44. Support 43 extends through aligned apertures in a wheel housing 45 and a liner 46, and is provided with a flange 4?. Flange 41 is provided with a pair of arcuate slots 48 which fit over a pair of studs 49 secured to housing 45, and a pair of nuts 5i are threaded on studs 49 and cooperate with flange l! to rigidly maintain the latter in contact with lionsing 45. If desired, nuts 5i may be loosened and support 43 rocked about the axis of the mechanism to dispose the deflector assembly in various angular positions, to thereby vary the direction of the discharge from the rotor in a manner to be hereinafter pointed out.

In order to properly center the support, to thereby accurately position the deflector assembly within the cup, a plurality of set screws 52 are threaded into the support and are adapted to be locked in place by nuts 53. Accordingly, by loosening nuts 53, set screws 52 may be threaded in or out to shift the support transversely to the axis of rotation (assuming nuts 5| have been loosened for this purpose) and the proper position accurately attained.

Spout 35 is supplied with abrasive in any suitable manner but preferably metered and from a gravity drop to impart the desired initial velocity to the abrasive. The abrasive fed into the spout is quickly conveyed to the center of the cup and promptly attains the full peripheral speed of the cup. After a predetermined quantity of abrasive has accumulated in the cup it builds up to its angle of repose therein. If the feed of abrasive to the cup be arrested, at this point, the abrasive already in the cup will remain on the wall of the cup and will not discharge over edge 33. In Figure 1 the surface of the abrasive when the cup is full is indicated by the line GI, and the angle of repose, which is the angle between this line and a line parallel to the axis of rotation of the mechanism, is designated as 62.

The deflecting assembly may assume various forms, and in Figure 1 it assumes the shape of a flange 63 which is so shaped as to generally conform to the cone-shaped layer of abrasive lying in the cup and is. accordingly, a helix of increasing radius toward the discharge edge of the cup.

As more clearly seen in Figure 6, the outer edge 64 of flange 63 is bevelled to substantially conform with the angle of repose of the abrasive lying in the cup. Flange 63 extends for approximately three quarters of a revolution or 270", with the result that the abrasive which is additionally fed to the cup and builds up therein beyond the angle of repose, starts to undergo an axial deflection at a point 65, and-is finally deflected over the discharge edge of the cup when it attains the point designated as 66.

It has been found that it is not necessary to "plow through the abrasiveon the rim of the cup, but it is merely necessary to disturb the abrasive or impart a slight initial movement thereto, because the cone of increasing radius compels the abrasive to continue moving down the incline until it is discharged over the edge of the cup. Therefore, the abrasive does not produce severe wear on flange 63.

At the point 66, flange 63 merges with a substantially cylindrical flange 61 which has little,

if any, pitch and which may be termed a splash deflector. As seen in Figure 1, flange 67 lies substantially in the plane of the discharge edge 33 and it functions to prevent abrasive which may inadvertently or prematurely be started down the incline from discharging over the edge of the cup before the proper discharge point is attained. Flange 6T, accordingly, torminutes at the point 68 to permit the discharge at point 65 of theabrasive that is actedupon by flange 63. The abrasive lying on the in-- terior of the "cup is, accordingly, deflected over the edge thereof at a predetermined point in the rotation of the wheel and stray abrasive is prevented by flange 61 fromleaving the cup elsewhere.

The deflector in Figures 1, 2 and 6 is shown as being adjusted to cause the abrasive to be dislodged from the rim of the cup at approximately the twelve oclock position. The abrasive is thrown substantially tangentially, as indicated by the arrows H in Figure 2, by reason of the fact that the abrasive possesses substantially no radial velocity and is traveling at the peripheral speed of the cup at the instant of discharge. The discharge from the rim accordingly assumes the form of a slightly fan-shaped continuous ribhon which. is cut by the inner ends of the blades as they successively pass through it.

It is also apparent that as theabrasive discharging from the rim is traveling in the same general direction as the inner endsof the blades it is picked up with a minimum impact. The abrasive picked up is smoothly and continuously accelerated by the bladesand is discharged from the outer ends thereof in a downward direction as indicated by the arrows 12. If it is desired to change the direction of discharge, nuts M are loosened and support" is rocked so as to simultaneously rock the dcflectonassembly in the proper direction to effect the desired direction of discharge. The degree of adjustment ailorded by the slots at oi. Figure 2 allows the discharge stream to be adjusted through approximately 90. l 1

If it is desired to direct the discharge upwardly, the support 43 may be removedinverted and replaced in the mechanismso as to locate the deflector assembly 180 from the position shown in Figures 1 and 6, to effect a downward discharge of abrasive from the cup and an uptlon involved. a

The invention, accordingly, provides a bladed centrifugal abrading machine having definite directional control and yet which does not embody a stationary feed cage having a slot for feeding the abrasive to the blades;

When the parts have become so worn as to require replacement, nuts l' are removed and the feed spout and deflector assembly are removed from the machine. Nut and bolt assemblies 44 may then be loosened topermit the deflector as sembly to be removed and replaced. Also, it the cup requires replacement at this time, screw 21 may be unscrewed to allow the cup to be removed.

The arcuate length, measured in degrees, of the discharge band from the wheel is greater than and directly proportional to the arcuate length, measured indegrees, of the discharge band from the cup, and, therefore, in some installations where it is desired to direct a com centrated stream of abrasive upon the work.

. means may be employed to restrict the, arcuate length, measured in degrees, of the discharge from the cup designated by the arrows It in Figure ,2, and in Figures 7, 3 and 9 I have shown one form of means "that may be employed for this purpose, l

With continued reference to these figures, flange ll of part D is cut away for portion of its periphery to allow a guard assembly G to be bolted securely to flange 42 of support 43. The guard assembly comprises a base pen tion I5 which is provided with a pair of open lugs I6. Bolt and nut assemblies cooperate with openings l6 and a pair of corresponding open" ings in flange 42 (not shown) to secure the guard assembly in place on support lB. Formed on base 15 is a generally cylindrical main guarding surface'il' which overlaps the outer periphery of cup C and is provided with a bevelled surface It so as to allow it to fit closely to the cup.

In Figure 8, the discharge edge 33 of the cup is indicated by a broken line and the main discharge of, abrasive from the cup is designated by the arrows 19. Also illustrated in this figure arearrows 3i which indicate a small spray or premature discharge of the abrasive and it is apparent. that with guard 11 in place the stray abrasive indicated by arrows Si is restrained from discharging into the blades and possibly being prematurely discharged therefrom. The stray abrasive particles rebound from the inner surface of guard 11' to join the concentrated stream being discharged from the edge of cup C.

InrFigure 10 I haveillustrated a deflector assembly D of slightly modified form and which is provided with a splash deflector or flange 61a which cooperates with the cup C in a somewhat dlflerent manner; 7

' As pointed out in connection with Figures 1 to 6, inclusive, the splash deflector or flange 81 prevents any abrasive that is prematurely dislodged from thesurface of the abrasive lying in the cup from being discharged onto the blades, and this action of the flange is enhanced by loeating it some'distance rearwardly of the dis charge edge 33 so that it directly cooperates with the surface of the abrasive lying on flange 28, with the result that the abrasive can only escape from the cup where the flange 61a is discontinued, namely, between points and 68 (Fig. 6). Asthe angle of repose assumed by the abrasive is ccnstantfor any given set of operating conditions, and cannot build up beyond this angle between the discharge edge and flange No, the latter, accordingly, prevents stray abrasive from escaping from the cup.

It has been found in practice that all of the parts 01' the deflector assembly function 000] in operation and wear thereof is slow. Flange We only lightly bears against the surface of the abrasive, and as previously pointed out, deflector flange or helix 63 serves to initially dislodge the abrasive and the fact that the cone is of increasing radius in the direction of thedischarge edge causes the abrasive to tend to continue more down the incline. However, the full length of helix 83 contr ls the flow of abrasive across the conical surface until it is finally discharged over edge 33, Wear of the helix is slow, however, be-

cause of the major force impelling the abrasive toward the discharge edge is supplied by centrifugal force, and the helix merely exerts a minor or light following action upon the abrasive.

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 th 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, a structure mounted for rotation at high speed and having a plurality of abrasive propelling blades provided thereon, said blades terminating short of the axis of rotation of said structure to define a central abrasive admitting space, a cup disposed in said central space and mounted for synchronous rotation with said structure, means for feeding abrasive to said cup, means for deflecting abrasive from said cup onto the inner edges of said blades at a predetermined point in the rotation of said structure, and stationarily supported guarding means interposed between said cup and the path of rotation of the inner ends of said blades for exerting a confining action upon stray abrasive deflected at points other than said predetermined point and directing it onto said blades.

2. The abrading apparatus defined in claim '1, wherein said deflector means and said guarding means are mounted for adjustment into a plurality of angular positions about the axis of said structure, for selectively varying the direction of discharge of abrasive from said blades.

3. In an abrading apparatus, a rotor having a plurality of abrasive propelling blades of a length to dispose their outer ends sufficiently radially distant from the axis of the rotor to propel the abrasive at an abrading velocity, said blades terminating short of the axis of rotation to define a central abrasive admitting space, an abrasive receiving cup disposed in said central space and having a generally cylindrical annular wall facing the axis of rotation to provide a substantial capacity for abrasive relative to the angle of repose, said cup being adapted to rotate synchronously with said rotor and being of a relatively small diameter so thatabrasive thereon travels at less than an abrading velocity, means for feeding abrasive to said cup, and deflector means for dislodging abrasive from said cup over the inner ends of said blades, at a predetermined point in the rotation of said cup, said deflector means comprising a member having a helical deflecting surface of increasing radius in one direction for progressively acting upon the abrasive lyingupon the walls of said cup.

4. In an abrading apparatus, a rotor having a plurality of outwardly extending abrasive propelling blades of a length to dispose their outer ends sumciently radially distant from the axis of the rotor to propel the abrasive at an abrading velocity, said blades terminating short of the axis of rotation to provide a central space, a cup located in said central space and having an inabrasive thereon travels at less than an abrading velocity, and stationarily supported deflector means projecting into said cup and having a generally helical surface cooperating in scraping engagement with the abrasive lying on said wall for deflecting the same over said discharge edge onto the inner ends of said blades at a predeter-r mined point in the rotation of said rotor, and means to prevent the discharge of abrasiv over said edge at other than said predetermined point.

5. The abrading apparatus defined in claim 4, together with a stationary guard member located between said cup and the inner ends of said blades for exerting a guiding action upon stray abrasive issuing over th discharge edge of said cup.

6. In an abrading apparatus, a rotor having a plurality of outwardly extending abrasive propelling blades of a length to dispose their outer ends sufliciently radially distant from the axis of the rotor to propel the abrasive at an abrading velocity, a centrally disposed cupwith a substantially cylindrical wall to provide a substantial capacity for abrasive relative to the angle of repose and mounted for synchronous rotation with said rotor, and having an inner wall of a relatively small diameter so that abrasive there! on travels at less than an abrading velocity, means for feeding abrasive to said cup, and stationarily supported means having a helical surface for causing abrasive in said cup to be discharged from said cup onto said blades adjacent wardly facing generallycylindrica] annular wall 4 abrasive discharge edge located adjacent the inner ends of said blades, means for feeding abrasive to said cup, said inwardly facing wall being of a relatively small diameter so that the the inner ends thereof at a predetermined point in the rotation of said rotor, said helical surface increasing in radius as it approaches the discharge end of said cup.

-7. A transfer mechanism for use with a centriiugal abrading rotor comprising a cup, means to feed abrasive to the interior of said cup, a closure at the open end of said cup, means to rotate said cup relative to said closure, andv means fixed to said closure and extending into said cup to effect the delivery of abrasive from said cup at a predetermined point.

8. The combination claimed in claim '7 wherein said feed means extends through said closure.

9. In an abrading apparatus, a rotor having a plurality of blades, a centrally disposed cup rotatable with said rotor and located in cooperative relationship with respect to said blades, 8. stationarily supported deflector assembly projecting into said cup and mounted for angular adjustment about the axis of said rotor, said deflector assembly having a substantially axially directed passage therein communicating at one end with the interior of said cup, and a stationarily supported feed spout having a substantially axially directed portion projecting into said passage of said deflector assembly, said spout and passage fitting sufliciently tight to preclude abrasive leakage, but sufficiently loos to permit said deflector assembly to' be adjusted without disturbing the position of said feed spout.

10. Apparatus for delivering abrasive at an and including a cup rotatable with the rotor, said cup having a substantially cylindrical wall to provide a substantial capacity for abrasive relative to the angle of repose, and. having its discharge edge lying in a plane which is transverse to said axis or rotation and between the ends of the inner edges 01 the blades, and a stationary but adjustable member including a blade of helical rorm disposed about said axis of rotation, one end of the blade terminating within the cup remote from said edge, and the other end terminating adjacent the discharge edge of the cup to deliver abrasive from the cup into the path of rotation of the blades, said blade increasing in radius toward the discharge end of said cup, the radius 01' the cup being so related to the radialdistance to the outer edged the blades that when the outer edge oi the blades is moving at a speed to impel the abrasive at an abrading velocity, the abrasive issuing from the cup will be at a low velocity.

-11. Apparatus for delivering abrasive at an abrading velocity comprising a rotor having a plurality of blades arranged substantially radial with respect to the axis of rotation of the rotor: a feed spout delivering abrasive near said axis of rotation; and a transfer mechanism interposed between said spout and said blades including a cup rotatable with said rotor with its discharge edge lying substantially in a plane transverse to said axis and between the ends of the inner edges of said blades, means to deliver abrasive from said cup into the path of rotation of said blades including a helical blade disposedabout said axis and extending from a point within said cup to a point adjacent the discharge edge oi said cup, and means to prevent a substantial discharge of abrasive from said cup except at said latter point.

12. The combination claimed in claim 11 wherein said last named means includes a deflector disposed adjacent the discharge edge of said cup.

13. The combination claimed in claim 11 wherein said last named means is positioned substantially parallel to and adjacent the discharge edge of said cup over a major portion of said edge.

14. The combination claimed in claim 11 wherein said last named means is positioned substantially parallel to and adjacent the discharge edge of said cup over a major portion or said edge, said means being fixed relative to said helical blade.

15. The combination claimed in claim 11 wherein said last-named means includes a de flector disposed adjacent the discharge edge of said cup, said deflector constituting a continua- 25 tion of said helical blade.

WALTER L. gamma.

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