US2468014A - Abrading apparatus - Google Patents

Description

April 19, 1949. w, L, KEEFER 2,468,014

ABRADING APPARATUS Filed Jam. 14, 1946 3 sheets-sheet 1 April 19, 1949. w. l.. KEEFr-:R- 2,468,014

ABRADING APPARATUS Filed Jan. 14, 194e s sheets-sheet 2 `April 19,1949. w. L. E EFER 2,468,014

v ABRADING APPARATUS Filed Jan. 14,*1946 s sheets-sheet s Patented Apr. 19, 1949 ABRADING APPARATUS Walter L. Keefer, Hagerstown, Md., assignor to Pangborn Corporation, Hagerstown, Md., a corporation of Maryland Application January 14, 1946, Serial No. 641,095 Claims. (Cl. 51-9) This invention relates to abrading apparatus at the castings at considerable velocity to break loose this foreign matter. It will be apparent, however, that objects other than castings may be subjected to this cleaning action of the abrasive stream.

Various machines have been devised in the past to carry or suspend the articles to be cleaned and bring them into the path of the abrasive stream and then carry them out of the stream. These machines, however, have generally been of complex and therefore expensive construction, and have required a large iioor space.

An object of the present invention is to provide a machine which is of relative simple construction but which results in effective cleaning of the articles it handles.

Another object of the invention .is to provide a machine of this type which is of relatively simple construction because it is practically reduced to the essential elements of a blasting station and a work loading and unloading station. The invention, however, contemplates the additional provision of a touch-up station at which the articles can be further cleaned by a manually directed blast stream.

Another object of the invention is to proportion the concentration of the stream to the cleaning requirement of the articles as they are disposed in the blast stream. In this respect, the blast stream is caused to play upon the articles for a longer period of time during the portion of their travel at which they are moving at the greatest speed, as this compensates for the tendency for uneven cleaning to occur.

In general, the apparatus of the invention includes a hanger from which a plurality of articles to be cleaned are suspended. This hanger does not travel-.while it is being loaded or unloaded and this facilitates the manual handling of the articles.

After the hanger is loaded, it is moved into the path of the blast stream and the travel of the hanger is then stopped but it is rotated to bring the articles into the blast stream. While the hanger is being rotated, the blast stream is moved back and forth to cause the abrasive to strike all surfaces of the articles.

The machine provides more than one hanger So that one may be in the blast station while another is in the loading or unloading station. By having a third hanger, a second blasting or touch-up station may be provided. It is not necessary to have more than these three hangers and three stations. The machine also includes the partitions for isolating the several stations from each other and these partitions travel with the hangers in accordance with the invention.

A preferred embodiment of the invention is illustrated in the accompanying drawings but it is to be understood that the invention is not limited to the details of this construction.

In these drawings:

Fig. 1 is a iront elevational view of the portion of the complete apparatus which is above floor level.

Fig. 2 is a plan view of Fig. 1, portions being broken away to show the construction.

Fig. 3 is a section on the line 3-3 of Fig. 2.

The housing of the machine includes a portion oi a generally cylindrical side Wall lll and an overlying top wall Il. These walls should be of relatively heavy sheet metal and may be assembled in any desired manner as by riveting or welding. As is apparent from Fig. 2, the side wall l0 does not make a complete circle, but is slightly more than 240 in arcuate extent.

This open portion of the side wall ID provides the loading and unloading station. At about therefrom, in the form shown, the side wall Ill is also removed to form an opening indicated at l2. This opening l2 communicates with a vestibule portion of the housing,r formed by two arcuate Walls I3-|3. The walls I3 are of the same radius of -curvature having a common center. The tcp wall ll overlies the walls I`3-I3 to form a covering for the vestibule. This vestibule contains the abrasive throwing apparatus, as will be explained later.

The side Wall I U is also removed to form an opening I4 which is about 120 from the opening l2 in the form shown. This opening |4 enters into a side chamber having side walls I5 and the tcp wall overlies the walls |5 to complete the enclosure. Access should be had to this side chamber through an outer door. This chamber, as will be explained, is provided in the form shown to accommodate the attendant who is to touch-up the cleaned articles by applying a blast to the foreign matter still adhering to them, if and when required.

The housing rests upon a grating |5 and may ce held in fixed position thereon by any suitable means. This grating IS is preferably at floor level. The grating at the bottom of the vestibule having side walls |3 is lower than the grating l5, as appears from Fig. 3. This increased depth is to accommodate a blasting machine, as will later appear.

Disposed within the housingy and along the axis of the side walls I0, is a vertical shaft 2i). This shaft 25 is rotatably mounted at its lower end upon a supporting antifriction bearing 2|. The inner raceway of bearing 2| is supported upon a stud 22 mounted upright in a reinforced portion of the grating I5. A beam 23 may be positioned beneath the stud 22 to further carry the load.

At the upper end of the shaft 25 is a cap 24 and from the top of this cap extends upwardly a bearing pin 25. Pin 25 is rotatably mounted in a bearing 25 which is affixed to the top wall 1| of the housing. As here shown, the vertical shaft 23 is a tubing to reduce its weight, but this is not necessary.

Projecting radially from the shaft in the illustrative embodiment are three arms 28. As here shown they are attached to the cap and this may be by any means, as welding. These arms 28 are at the upper endof the shaft 20 and are 120 apart in the form shown. As here shown the arms 28 are each made up of spaced side rails having a block 25 between them at their outer ends, but they can be solid or be of other construction.

Within the outerv end of each of the arms 28 is rotatably mounted a shaft 3|. This shaft 3|, in the arrangement shown, passes vertically through the block 29 and is held therein against downward movement by any suitable means. The upper end of shaft 3| has a cross sloi 32 therein to be engaged for driving the shaft 3|, as will later appear.

Secured to the lower end of each shaft 3| is a work holder 33 made up in the form of a spider having a plurality of radial arms. These arms have notchesk 34 along their upper faces to receive hooks by which the articles to be cleaned, are suspended. A hook 35 is beneath the axis of the holder 33 to receive a large object to be cleaned.

As a feature of the preferred form of the in vention, the holder 33 which is in the blast stream is rotated about its axis. This is accomplished by means of a driven shaft 36 and a jaw clutch 37. The jaw clutch 31 is keyed to the shaft 35 and is movable up and down along the shaft to bring the jaw clutch 37 out of, or into engagement with the shaft 3|. When the clutch 37 is moved downwardly it engages the slot 32 in shaft 3| to rotate it.

Jaw clutch 37 is moved up and down by a lever 38 pivoted at 39 to a bracket onthe top wall of the housing. A pin lill at one end ofthe lever 3B enters a circular groove 4| around the jaw clutch 3l. At its other end the lever 38 is 4 pivoted to a hinging link 42 by which the attendant may move the jaw clutch 31 up and down. To retain the link 42 in the position in which clutch 3l' is engaged or disengaged, it is formed with two -openings 43 Fig. 1, which may engage a pin 44 projecting from the housing.

Shaft 36 is driven through a gear reduction box 45, and a belt drive 4l, by a motor 33. When it is desired to move the work holder 33 which is in the blast stream, to the next station, the jaw clutch 31 is rst moved upwardly. After the next work holder is brought to the blasting station, the jaw clutch 31. is moved downwardly to engage and drive it.

Disposed midway between each pair of work holders 33, is a partition 55. These partitions are attached to the vertical shaft 2D and project radially therefrom. Braces 5| extend between the partitions 5i) and the arms 28 to interconnect and afford a mutual support between them. The partitions are large enough to extend nearly to the side wall|ll, the top Wall and the oor grating I5.

Flexible material 52 is attached to the outer vertical edges of partitions 50 to bear against the side wall El and form a seal. Similar sealing strips 53 and 54 are affixed to the top and bottom edges of thepartitions 55 to bear against the top wall and grating |5, respectively. Due to the presence of these partitions 5U, each Work holder 33 is segregated within its own chamber when in the blast stream. The sealing strips 52, 53 and 55 around the edges of the partitions prevent the escape of abrasive from this particular chamber in which blasting is occurring.

Handles 55 are afxed to opposite sides of each partition 55 tobe grasped in rotating the entire assembly consisting of the -central shaft 20, the arms 28 and their work holders 33, and the partitions 50. While it is intended that this indexing be done manually by pushing or pulling on these handles 55, it will be apparent that power means may be utilized'to index the rotating assembly to move the article holders 33 to their successive positions.

It is important to accurately position the article h -ders 33 aseach one is brought to the blasting station, in order that its shaft 3| will be in line with the jaw clutch 31 to be driven thereby. To obtain this accurate positioning, stop means are provided and this includes a movable stop arm 5l against which may bear an adjustable screw 58 on each partition 55. The stop arm 5l is attached to a shaft59 which is pivoted in a box-like receptacle Si] ai`xed to the side wall ||J close to the hanging link 42. The shaft 59 extends outside of the receptacle 55 and is bent to form a handle portion 5| by which the shaft 59 may be rotated.

Ordinarily, the stop arm 5'1 will be in the downward position shown, so that it will be struck bythe adjustable bolt 58 to limit the rotation of the partition 55 as it is advanced. By screwing each bolt 53 in or out and then locking it in this position, accurate indexing will be obtained for each article holder. When the work holders are to be advanced, the shaft 59 is turned by means of its handle portion 5| so as to turn the stop arm 51 to an upper position in which it enters the receptacle 60 and is out of the way of the partitions 50.

It has been stated that" the vestibule having sidewalls I3, houses the abrasive throwing apparatus which projects the abrasive against the articles to` be cleaned'.V Thisv abrasive is projected through the opening at |2 in the side wall l of the housing and against the articles suspended from the particular work holder 33 which is in the blasting station.

As here shown the abrasive throwing apparatus is a plurality of machines 63 and 64 which serve to propel the abrasive by the action of centrifugal force. A suitable machine which operates on this principle is disclosed in Patent No. 2,320,364 issued to Walter L. Keefer on June 1, 1943. However, any other device which delivers abrasive at high velocity and in a concentrated stream, may be utilized. As here shown there are four of the abrasive throwing machines 63 and 64, but this is not a necessary number. I

In the form shown a plurality of the abrasive throwing machines are mounted upon a vertically disposed plate 65 within the vestibule. Secured to the lower end of plate 65 and centrally of the width of the plate is a block B8 from which, depends a stub shaft. 61. The stub shaft 61 is supported by an antifriction bearing 68 mounted in-a socket in a pedestal 69. The pedestal 69 may be supported in any suitable manner. I

To the upper end of 1| from which a shaft 12 projects vertically upwardly in axial alignment with the stub shaft 61. This shaft 12 is rotatable in a bearing 13 mounted on the top wall of the housing and the shaft eX- tends above the top of this bearing 13. The stub shaft 61 and shaft 12 therefore serve as trunnions to rotatably support the plate 85.

It is important that the axis of the shaft 12 and stub shaft 61 be coincident with the axis of the side walls I3 of the vestibule in which plate 65 is located. The verticaledges of plate 65, as a consequence, may extend close to the walls I3 and sealing strips 14 attached to these edges remain in contact with the walls I3 as the plate 65 is pivoted about its axis of rotation.

The upper two abrasive throwing machines 63 are driven by a motor 15 carried on a standard 16. This standard 16 and the bases of these two upper abrasive throwing machines 63 may be attached in xed positions to the plate 65. The lower two abrasive throwing machines 64 and the standard 11 mounting their driving motor 18, preferably are adjustably attached to plate 65 for up and down movement. By this adjustment, the lower machines 64 may be raised or dropped in position to blast shorter or longer articles being cleaned.-

From Fig. 3 it will be apparent that each of the two upper blast machines 63 are so disposed that they throw the abrasive in an overhand relationship between the arrows 80 whereas the two lower blast machines 64 are disposed to throw vthe -abrasive in an underhand manner between the arrows 8|. Because of this arrangement the two upper blast machines 63 throw abrasive in a generally downward direction so that they will blast upwardly facing surfaces as well as the vertical faces. The two lower blast machines 64 throw abrasive in a generally upwardly direction so that they will blast downwardly facing surfaces and the vertical faces. As a consequence all horizontal, vertical and angularly disposed surfaces of the work pieces will be cleaned.

As the upper blast machines 63 throw abrasive generally downwardly as appears from arrows 80, and the lower blast machines 64 throw abrasive generally upwardly as appears from arrows 8|, their streams would clash if they were in the same plane. To avoid this clashing, the two upper blast machines 83 are displaced laterallyfrom the two lower blast machines 64,. Asaconseguen'ce plate 65 is secured a block 'full Width Of" the `By this means the vertical plane containing -the t'wo upper 'streams 80 is sideways from the vertical plane Itransported or advanced untilthe cleaning is completed. The rotation of the article holder .33 brings all the articles into the blast streams, but as afurther feature of the invention the blast streams are oscillatedl back and forth across the articles suspended from the holder 33. Thus, referring to Fig. 2, the blast streams are oscillatedback and forth between the lines 82.

The blast streams 8U and 8| are oscillated between the limits indicated by lines 82, by oscillation of theplate 65 carrying the abrasive throwing machines |3and 64. This is accomplished by oscillating vthe Ishaft 12 by means of an arm 83 attached to its upper end. A connecting link 84 is pivoted to the outer end of arm 83 and joins it to the outer end of a crank arm 85.

Crank arm 85 is continuously rotated about a complete circle .by its attachment to a shaft 88 projecting from aspeed reducing gear box 81. Gear box.81 is driven through a belt drive 88 by a motor 89. The throws of the crank arm 85 and of the arm 83 are so proportioned to each other that the abrasive throwing machines 63 and 64 will swing to such an extent as to move their blast streams back and forth between the lines 82. If desired these throws can be adjustable to permit regulation of the angular space between lines 82.

the centrifugal projector is manipulated so as to turn the ends of its rotor axis alternately toward and from the work to sweep the fan-shaped stream across the work in a fanwise Liiiimanner on each movement of the arm 83.

From Fig. 2 it will be apparent that the crank arm is passing through its dead center positions when the blast streams are at the limits of their sweeping movement as represented by the lines 82. This fact is taken advantage of in the present invention to cause a more equalized blastingof the articles, irrespective of their position toward or away from the center of the work holder 33. It will be apparent that more articles can be suspended from the periphery of the work holder 33, than can be located near the axis of the work holder. Also, these articles at the periphery of the work holder 33 travel at a greater linear speed than do the articles near its axis of rotation.

As a consequence of this location of more articles at the outerl part of the work holder, and their greater -speed of travel, more blasting must be performed upon them for them to be cleaned as much as the articles nearer the center of the work holder. This result is obtained with the present invention because at the outer limits, represented by the lines 82, of the blast streams, the crank arm 85 is passing through its dead center positions. At its dead center positions, the crank arm 85 causes a retarded or delayed motion of the blast streams so that they tend to dwell in the two positions at the lines 82. Therefore, although there 'are many articles in the-path of this stream and they are traveling rapidly, they receive considerable blasting. The articles close to the axis of the workholder .33 are not over blasted as the blast streamisuponthem only as-it is sweeping past the axis 'ofthe work holder.

. To receive and collect the abrasive after it falls 4no' the artigieabeing cleaned,V the grating is accorcia :and i1 is .located over a 'hopper Lina. pitlocatedibelov;7 'thenoor level. This .collected abrasive is fed `as by .fa vscrew conveyor., 'to .the lower :end :of ya bucket elevator 9| (Fig. 2) inside of vertical caising .52. Elevator 91 lifts `theabrasive to a point from which it descends 'by gravity .through .a closed chute 93 into the `abrasive cleaner 39B. This abrasive 'cleaner 94 may be of conventional construction.

The cleaned abrasive from cleaner $4'. descends through chute 295 to the lowerendof 'bucket'V eleva- 'tor .9B (lig.f2), also in the` casing :9.2. An 'orifice plate 4Sl'l regulates flow ythrough.@chute 85, and-a valve 98 permits it to quickly Kenton. .Elevator 96 lifts. the abrasive to aA point .from which it. :can

descend by gravity vthrough chute 99 to a `distributingboxilu.

'From Ithedistributlng box" m0, .leadilexible-conduits :to2 to 'the upper :blasting malclnines E3, :and flexible rcondlvxiits. 103 rto `the lower blasting ma `chines. 164. Also leading :from ith-'e :distributing 'box l Vis .aconduit |04 leading to .a container :185. Abrasive is v'drawn .from container itil-5 through a conduit 106 to nozzle 1'01 fin-the M4touch up :chamber having side walls l 5.

The abrasive .is consequently reclrculated through the apparatus for reuse in 'the .blasting machines 63 .and 64. The abrasive is cleaned in the cleaner 9'4 to remove the broken fines andvalso to eliminate the foreign :matter .removed fromthc articles being cleaned. Dust is removed from `the housing by a suction applied. at the openings EH18.

In operation, the blasting vmachines are con stantly .in operation delivering 'abrasive and are being oscillated-by means of crank. arm 85` and the connecting linkage. While one work holder 33i's lbeing rotated in 'this blast stream, the second work holder 33 .is being unloaded of. cleaned-articles and loaded with uncleaned articlesa'titheopen section ofthe housing. The third work holder :33 is at this time :in the ltouch up'lstat`ion where its articles are vbein-g .nis'h cleanedby'an operator using the -nozzle 101.. As has been stated, the touch up operationsand station can be omitted.

'The timerequired to unloadandload one work holder'is about the same 4time required to clean .the articles in theblasting station` This cleaning operation can be 'controlled ifor best. .results 'by varying the :ratio betweenthe number-vof `times the blast streams sweep back` auditor-'th for each revolution `of the 'work holder 33. It has been' found that excellent resultsarevobtained ifrthere :are about eight oscillations yof the Iblast ,stream for each revolution-of the work.

.'I claim':

I. .Apparatus 'for .blast cleaning articles :comprising 'a housing closed at one section 'to provide a blasting station and open at oner'section toprovide a loading :stat-ion, atleast .two work holders, means .supporting the 'work holders to move-'one into the blastingA station as another is moved simultaneously therewith into the loading station, a partition connected 't'o vsaid-means-and located between 'each pairof work holders to: cooperate with the housingr 'in sealing relation and segregate the blasting station, said 'housing hav ing a vestibule in fopen communication with said blasting station, an oscillatable p'latefin s'aid ves'tibul'e having a ysealing contact withfthe vestibule wall as it 'oscillatea 'abrasive vprojecting''means supported' by said'. plat-e and delivering abrasive at` blasting' velocity intofthe 'blasting ,station 'to clean the articles, and mea-nsI .for oscillating-'said platefto sweeplthe Iabrasive' stream 'back @and forth overthe articles -zin the blastingrstation.'

2. .Apparatus for blasting :cleaning articles comarising a generally cylindrical upright housing .closed at one section .to provide a blasting station and-open at another 4section'to provide a loading Vstation,atleast two -work holders, means supporting'the work holders for movement in a circle about .the axisxof said 'housing vso that one work holder movesinto 'the blasting station 'as another .i'scnroved simultaneously therewith into the .loadingfgstation, av partition- Iconnected to said means ranjdlocated'. on. oppositesides of each 'Work holder tovrnove' with them, said partitions extending into sealing contact with the housing to segregate the 'blasting station, lsaid housing having a vestibule in open communication with lsaid blasting'station, .anjoscrllatable plate said vestibule having a sealing-contact.' with the vestibule wall as it oscillates,. a'brasive proj ectingimeanssupported by said :plate and delivering abrasive `at `.blasting velocity into .the blastingstation to clean the articles, 'and means for v'oscillating .said :plate to .sweep the 4'abrasive .stream .Ibac'k Iand -forth :over the articles in the 'blastings'tation- '3. Apparatus for blasting lcleaning articles comprising a generally cylindrical upright housing having a vestibule offset from a section of the housingl which serves as a blasting station, the 'vestibule being in open communication with the Yblasting station `and the side Walls of the vcsti- 'buie 'being arcuate about "a vertical axis, abrasive :projecting `means linthe vestibule projecting abrasive into said blasting station, mounting means for said abrasive projecting means and having `os'cillata'ble movement about the axis of said vestibuie, said. mounting means having a sealing contact with the arcuate walls of said `vestibule during oscillationof the'mounting means, means for oscillating. the mounting'means, at least two work holders, 'means supporting the work holders to move one into the Iblasting station as another is moved simultaneously therewith into the loading station, and a partition connected t-o said supporting rnean-s andlocated between each pair of work holders and extending into sealing relation with sa'i'generally cylindrical housing.

2i. Apparatus for blasting cleaning articles com- :prising va generally cylindrical upright housing having 'a vestibule offset from a section of the 'housing' 'which serves as a-blast'ing station, the vestibule being in 'open communication with the blasting station and the side walls ofthe vestibule being arcuate about a vertical axis, abra-sive protecting-means in thevestibule projecting abrasive 'into said blasting station, mounting means for said abrasive vprojecting means and having oscillatable vmovement aboutthe'ax'is of said vestibule, said mounting means having a sealing contact with the arcuate `walls of said vestibule during oscillation o-f` the mounting means, means for oscillating 'the mounting means, at least two work holders, means supporting the `work holders to `move one into the blasting station yas another is lmovedA simultaneously therewith into the loading station, Va partition connected 'to said supporting means and located jbetween each pair vof work holders 'and extending into sealing relation with said generally cylindricalhousing, and means for rotating the work holder in the blasting station.

5. Apparatus for blasting cleaning articles corripricing a generally cylindrical upright 'housing having a 'vestibule offset 'from a section of the housing'whlcliserves as a 'blasting station, the vestfibulefbeing in open communication with the blasting station and the side walls Yof the vestibulebelng arcuate about'a vertical' axis-abrasive projecting means in the vestibule projecting abrasive into said blasting station, mounting means for said abrasive projecting means and having oscillatable movement about the axis of said vestibule, said mounting means having a sealing contact with the arcuate walls of said vestibule during oscillation of the mounting means, means for oscillating the mounting means, at least two work holders, means supporting the work holders to move one into the blasting station as another is moved simultaneously therewith into the loading station, and a partition connected to said supporting means and located between each pair of work holders and extending into sealing relation with said generally cylindrical housing, said oscillating means serving to cause the blast stream to dwell upon the extreme lateral limits of the oscillations.

6. Apparatus for blasting cleaning articles comprising a generally cylindrical upright housing having a vestibule offset from a section of the housing which serves as a blasting station, the vestibule being in open communication with the blasting station and the side walls of the vestibule being arcuate about a vertical axis, abrasive projecting means in the vestibule projecting abrasive into said blasting station, mounting meansv for said abrasive projecting means and having oscillatable movement about the axis of said vestibule, said mounting means having a sealing contact with the arcuate walls of said vestibule during oscillation of the mounting means, means for oscillating the mounting means, at last two work holders, means supporting the Work holders to move one into the blasting station as another is moved simultaneously therewith into the loading station, a partitionL connected to s aid supporting means and located between each pair of work holders and extending into sealing relation with said generally cylindrical housing, and means for rotating the work holder in the blasting station, said oscillating means serving to cause the blast stream to dwell upon the extreme lateral limits of the oscillations.

'7. Apparatus for blasting cleaning articles comprising a generally cylindrical upright housing having a vestibule offset from a section of the housing which serves as a` blasting station, the vestibule being in open communication with the blasting station and the side walls of the vestibule being arcuate about a vertical axis, abrasive projecting means `in the vestibule projecting abrasive into said blasting station, mounting means for said abrasive projecting means and having oscillatable movement about the axis of said vestibule,v

said mounting means having a sealing contact with the arcuate walls of said vestibule during oscillation of the mounting means, means for oscillating the mounting means, at least two work holders, means supporting the work holders to move one into the blasting station as another is moved simultaneously therewith into the loading stationa partition connected to said supporting means and located between each pair of work holders and extending into sealing relation with said generally cylindrical housing, and means for rotating the workvhol'der in the blasting station, said oscillating means including a constantly rotating crank arm having an operating connection to said mounting means, the dead center positions of said crank. arm corresponding to the extreme positionsl of the oscillations of the mounting means to cause the blast stream to dwell in these positions? v 8. Apparatus for blast cleaning articlesl come prising a generally cylindrical upright housing providing at intervals about 120 apart, a closed blasting station, a closed touch-up station, and an open loading station, three work holders, means at the axis of the housing supporting said work holders about 120 apart so that one is in each of said three stations, said means mounting said work holders for rotation about the axis oi the housing to'advance them simultaneously through said stations, upright partitions supported by said means midway between the work holders and extending into sealing relation with the cylindrical wall of the housing to segregate the three stations, and means for projecting abrasive at blasting Velocity upon the articles in the blasting station. l

9. Apparatus for blast cleaning articles comprising a generally cylindrical upright housing providing at intervals about 120 apart, a closed blasting station, a closed touch-up station, and an open loading station, three work holders, means at the axis of the housing supporting said work holders about 120 apart so that one is in each of said three stations,- said means mounting said work holders for rotation about the axis of the housing to advance them simultaneously through said stations, upright partitions supported by said means midway between the work holders and extending into sealing relation with the cylindrical wall of the housing to segregate the three stations, said work holders being sup` ported for rotation about a vertical axis centrally through the work holders, means for rotating the work holders when in the blasting station, means for projecting abrasive at blasting velocity upon the articles in the blasting station, and meansior oscillating the blasting apparatus to sweep the abrasive stream back and forth over the articles in the blasting station.

10. Apparatus for blast treating articles com- 40 prising a housing embracing a blasting station, said housing having a vestibule in open communication with said blasting station, an oscillatable plate in said vestibule having a sealing contact with the vestibule wall as it oscillates,

abrasive projecting means supported by said plate andr delivering abrasive at blasting velocity into the blasting station, and means for oscillating said plate to sweep the abrasive stream back and forth over articles being treated in said blasting station.

11. Apparatus for blast treating articles comprising a housing embracing a blasting station, means for supporting articles to be blasted in said blasting station, said means being mounted for rotation about a vertical axis, said housing having a vestibule in open communication with said blasting station, an oscillatable plate insaid vestibule mounted to oscillate about a Vertical axis and having a sealing contact with the vestibule wall as it oscillates, abrasive projecting means supported by said plate and delivering a stream of abrasive at blasting velocityinto the blasting station, yand means for oscillating said plate to sweep the abrasive stream from side to side along the path of rotation of articles carried by said supporting means. A

12. Apparatus for blast treating articles comprising a housing `embracing a blasting station, said housing having a vestibule in open communication with said blasting station, an oscillatable support in said vestibule, a plurality of centrifugal projectors mounted on said 'support for projecting into said blasting station fanshaped streams of treating particles orientedln generally parallel planes, and means for oscillating said support about-an axis generally parallel tothe planes of said streams'to sweep the projected streamsback and forth over articles being treated in said blasting-station.

y13. Apparatusfor blast `treating articles comprislng a housing embracing a blasting station, said -housing having a vestibule in open communication with said blasting station, an oscillatable support in said vestibule, a plurality of centrifugal projectors mounted on said support for projecting into said blasting station fanshaped streams of treating particles oriented in generally vertical planes, and means for oscillating said support about a vertical axis to sweep the streams back and forth over articles being treated in said blasting station.

14. Apparatus for blast cleaning articles coniprising a housing embracing Va blasting station, a work support therein, means for rotating said work support about a vertical axis, said work support comprising means for supportinga plurality of individual articles in spaced relation to said vertical axis to cause vthe same to travel thereabout, said housing having a vestibule in open communication with said blasting station, a support in said vestibule oscillatable about a vertical axis, particle projecting means carriedby said support and directedto discharge a stream of particles at blasting velocity into saidblasting station, and means for oscillating said support aboutits vertical axis to swing said stream from side to side along the path of travel of articles carried toward, past and away fromsaidprojecting means by said supporting means. f

15. Apparatus for blast cleaning articles comprising a housing embracing a yblasting station, a Vworls support therein, means for rotating said work support about a vertical axis, said work support comprising means for supporting a plurality of individual articles in spaced relation to said vertical axis to cause the same to travel thereabout, said housing lhaving a vestibule in open communication with said blasting station, a support in said vestibuleoscillatable about a vertical axis, particle projecting means carried by said support and directed to discharge a stream of particles at blasting velocity into said blasting station, and means for oscillating said support about its vertical vaxis to swing said stream from side to side along the path of travel of articles carried toward, past and away from said projecting -means by said supporting means, said oscillating means being timed to cause the blast stream to dwell at-the lateral limits of its oscillations during which it is directed toward articles spaced most substantially from said axis.

16. Apparatus V-ior'blast cleaning articles comprising a housing embracing a blasting station, `a work support therein, means for rotating said -work support about a vertical axis, said work support comprising means for supporting a plurality of individual articles in spaced relation to said vertical axis to cause the same to travel thereabout, said housing having a vestibule in open communication with said blasting station, a support in said vestibule oscillatable about a vertical axis, particle projecting means carried by said support and directed to discharge a stream of Vparticles at blasting velocity into said blasting station, and vmeans foroscillating said support about its vertical axis to swing said stream from side to side along the path of travel of articles carried toward, past and away from said pro- .iecting means by said supporting means, saidoscillating means being timed to oscillate said blast 12 stream a plurality of rtimes foreach rotation of said work support.

17. Apparatus forblast-cleaning articles comprising a housingembracingia blastingstation, a work support therein, means for rotating said work support about a vertical axis, said work support comprisingmeans for supporting a plurality of individual articles in spaced relation to said vertical axis to cause the same to travel thereabout, said housing vhaving a vestibule in open communication witn said blasting station, a support in said vestibule-oscillatableabout a vertical axis, particle projecting means carried by `said support and directedto discharge a stream of particles `at blasting velocity into said blasting station, and means -for oscillating said support about its vertical axis to swingsaid-stream from side to side along the path of travel of articles 'carried toward, past and away from saidprojectingmeans by said supporting means, said 'oscillating ymeans being timed to cause theblast stream to dwell at the lateral limits of its oscillations during which it is directed'towardarticles Aspaced most substantially from -said axis, and to Ioscillate said blast stream between said limits-a plurality'of times for each rotation of said work support.

18. Apparatus for blast cleaning articles comprising a generally cylindrical upright housing providing at intervals,r=aiirst .blastingV station, a secondblasting station, and anopen loading station, -at least three work holders, means at the axis of the housingisupportlng-said work holders so that one -is yin each of said three stations, saidy means mounting said work Iholders for rotation about the axis ofthe housing fto ,advance lthem simultaneously through said stations, upright partitions supported :by `said means midway between the work holders and extending into sealing relation with the cylindrical wall of the housing to segregate the .three stations, means for projecting abrasive atblasting velocity upon the articles inthe blasting stations -at last lone of said projecting means comprising a centrifugal projector oriented to project its fan-shaped blast stream in a verticalplane, Yand means for oscillating said icentrifugal projector about a vertical axis tosweep said fan-shaped stream back and forth over the articles being blasted.

i9. Apparatus for blast cleaning articles comprising a generally 4cylindrical upright housing providing at intervals, a yirst blasting station, a second blasting station, :and `ran open loading station, at least three work holders, means at the axis of the housing supporting said work holders so that one is in each or'said three stations, said means mounting said work holders for rotation about the axis of the housing to advance them simultaneously through said stations, upright partitions supported by said means midway between the -work holders and lextending into sealing relation with the cylindrical wall of the housing to segregate 'the three stations, said work holders being supported yfor rotationabout a vertical axis centrally through the work holders,

means for rotating the work` holders when in thek blasting station, a centrifugalvprojector oriented to direct its fan-shaped ystream vin a vertical plane; for projecting'abrasive at blasting velocity upon the articles in the `first blasting station, means lfor oscillating said centrifugal lprojector about a vertical axis kto Vsweep the `fan-shaped stream back and -forth fanwise over the articles in said blasting station, and means for projecting particles at blasting velocity upon the articles in the second blasting ,st-ation.

20. In a blasting machine, a work holder, a cen` trifugal projector positioned to blast work carried thereby, said projector being oriented to direct its fan-shaped stream against work carried by said holder, and means for turning said centrifugal projector in a direction to move one end of its rotor axis toward and the other away from the Work to sweep the fan-shaped stream fanwise across the Work.

WALTER L. KEEFER.

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

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