US2306842A

US2306842A - Abrading apparatus

Info

Publication number: US2306842A
Application number: US52767A
Authority: US
Inventors: Verne E Minich
Original assignee: American Foundry Equipment Co
Current assignee: American Foundry Equipment Co
Priority date: 1935-12-04
Filing date: 1935-12-04
Publication date: 1942-12-29
Anticipated expiration: 1959-12-29

Description

'7 Sheets-Sheet 1 ATTORNEYs Dec. 29, 1942. v. E. MINICH ABRADING APPARATUS 7 Sheets- Sheet 2 Filed Dec. 4, 1935 INVENTQR I Fme ZT/Vimtfi ATTO R N E? N NR Dec. 29, 1942. v. E. MINICH 2,306,842

ABRADING AP'PARATus Filed Dec. 4, 1935 7 Sheets-Sheet 3 3 L5 N INVENTOR 4 2 [@rnz 7 M11116];

ATTORNEYS ABRADING APPARATUS Filed Dec. 4, 1935 7 Sheets-Sheet 4 ATTORNEYS Dec. 29, 1942. v. E. MINICH ABRADING APPARATUS Filed Dec. 4, 1955 7 Sheets-Sheet 5 INVENTOR E fiim'riz/ ATTORNEYf Verne flaw Dec. 29, 1942. v. E. MINICH ABRADING APPARATUS Filed Dec. 4, 1935 7 Sheets-Sheet 6 Dec. 29, 1942. v. E. MINICH ABRADING APPARATUS Filed D90. 4, 1935 5 '7 Sheets-Sheet '7 Patented Dec. 29, 1942 UNWE ascetic annanma arrem'ros Verne E. Minich, Mishawalra, Ind, assignor to The American Foundry Equipment Company, Mishawaira, find a corporation of Delaware Application December a, 1935, Serial No. 52,767

8 Glaims.

This invention relates to the treatment of metallic articles, and particularly to a combination abrasive-projector and supporting device for the articles to be treated.

In the process of abrasively-treating the surfaces of articles, such as metal castings, forgings, bars and sheets, for the purpose of cleaning. P01- ishing or treating the articles by the abrasive effect of a stream of abrasive particles, it is desirable to support the articles in such a manner that all of the various surfaces of the articles to be treated are presented to the stream and are subjected to the effect of the abrasive stream for equal periods or for such relative periods that all of the surfaces are uniformly treated, or are each treated to the desired extent.

When the articles to be treated are of large size, irregular shape, brittle material, or otherwise dimcult to handle, or are fragile, it is difficult, and in many cases impossible, to support them in a tumbling mill or other analogous arrangement for presenting the various surfaces of the articles to the stream of abrasive. It is desirable that such articles be firmly supported in a manner to prevent damage thereto, but it is also desirable that they be so supported as to present to the stream all of the sides which it is desired shall be treated.

The present invention consists in providing a combination device supporting the articles to be treated and projecting a stream of abrasive material thereagainst, which device may include an abrasive-throwing or other analogous abrasiveprojecting means, together with a supporting device adapted firmly to support the articles to be cleaned and to move the articles through the stream while simultaneously turning the articles about in the stream in a predetermined manner to expose various surfaces of the articles to the impinging effect of the abrasive particles.

The supporting device suitably may consist of a conveying element such as a rotatable frame, table, conveyor or the like, mounted for movement past the abrasive-projector, and may have rotatably mounted thereon one or more table elements such as a turntable or an analogous element to support the articles to be treated. The

table elements through the stream of abrasive, and each table element is rotated about its axis at least during the time it is passing through the stream, so as to expose the various surfaces of the articles to the stream.

The abrasive-projecting device may be designed to project a stream of abrasive having a predetermined impingement pattern, and the supporting device may be designed to carry the table elements through the stream in such a manner conveying element is suitably driven to carry the V that all of the articles are subjected to an equal amount of treatment. One manner of accomplishing this consists in establishing a stream of abrasive defining an elongated impingement pattern and moving the table elements through the stream along the longitudinal axis of the pattern, whereby substantially all portions of the article or articles supported on each table remain in the stream substantially the same length of time. Another method of accomplishing the desired result consists in directing the stream of abrasive angularly to the path of movement of the table elements in such a manner that the portions of each table element having the higher lineal velocities are carried through the stream a greater number of times than the slower moving portions of the table elements, in proportion to their respective lineal velocities.

A suitable housing may be provided for enclosing the stream of abrasive, and the supporting device may be positioned to carry the tables into and out of the main portion of this housing so as to permit the placing and removal of articles on the turntables when outside the main housing. The drive for rotating the turntables on the frame may be arranged so that the turntables are not rotated when in loading and unloading position, thus facilitating the placing thereon and the removal therefrom of the articles to be treated.

An object of the present invention consists in the provision of a combined abrasive-projector for projecting a stream of abrasive, and a supporting device adapted to carry the articles to be treated through the stream and to turn them about in the stream in such a manner that various surfaces are exposed to the stream and efiectively treated.

Another object of the invention is the provision of a device of the class described, wherein the stream of abrasive is protectively enclosed in a housing in such a manner as to prevent undesirable scattering of the abrasive, but which housing permits ready access to the supporting device for loading and unloading purposes.

Still another object of the invention consists in the provision of a drive mechanism for turning Still another object of the invention consists in the provision of apparatus of the type described which is simple, rugged and compact in construction, which is rapid, efllcient and effective in operation, and which may be operated substantially automatically with a minimum of supervision and with safety to the operator or attendant.

Various other features and advantages of the invention will beapparent from the following particular description and from an inspection of the accompanying drawings.

Fig. 1 is a plan view showing a device constructed according to the invention;

Fig. 2 is a front elevational view of the device shown in Fig. 1;

Fig. 3 is a vertical sectional view taken along lines 33 of Fig. 1;

Fig. 4 is a fragmentary view, partly in crosssection, proper;

Fig. 5 is a diagrammatic plan view of the supporting structure of the apparatus shown in Fig. 1;

Fig. 6 is a similar view of a modified construction;

Fig. 7 is a front elevational view of still another embodiment of the invention;

Fig. 8 is a horizontal cross-section taken along the line 8-8 of Fig. 7:

Fig. 9 is a vertical cross-section taken along the line 9-9 of Fig. 7;

Fig. 10 is a fragmentary top plan view of a portion of the structure shown in Fig. 7; and

Figs. 11 and 12 are front elevational and top plan views, respectively, showing diagrammatically certain of the structure of Fig. 1, a nd illustrating how the articles are treated by the stream of abrasive.

The apparatus comprises broadly a housing structure I, on which is mounted a rotatable abrasive-throwing wheel 2, driven by a suitable driving mechanism 3, and adapted to project a stream of abrasive into the housing structure I, and a suitable supporting device 4 rotatable within the housing and adapted to carry articles to be treated through the stream of abrasive. A conveyor system 5 collects spent abrasive from the housing, and returns it to the abrasivethrowing wheel 2 in a manner which will hereinafter be described.

Supported on a substantially cubical framework constituted by suitably disposed and connected structural members, is a substantially rectangular main housing 2| having a

top wall

22 and 2. depending hopper and collecting trough portion 60. A forwardly projecting, horizontal extension 23 formed with a vertical side wall l9 extends from the housing and is supported on the framework 2|). A hood 24 extends downwardly from the top wall 22, .and partially overlies the extension 23, leaving the outermost portion open. Vents 2| are provided in the top Wall 22.

Mounted on the top wall 22 is a semi-circular housing 25 for the abrasive-throwing wheel 2, which housing is pivoted to the top wall 22 by means of extensions 26, rotatable on a pivot pin 21, journalled in a bearing 28. The housing 25 is maintained in closed position by a latch 29 which may be of any known construction, and which is provided with a handle 30 for releasing the latch and lifting the housing 25. I

The'abrasive-throwing wheel 2, preferably, is a wheel of the center-fed, centrifugal type similar to the wheel disclosed in Patent No. 1,953,566

showing the supporting mechanism to Peik, although any wheel of this general type may be employed. It is preferable, however, that the wheel be one adapted to directionally project a controlled stream of abrasive against the articles resting upon the moving support.

Th wheel 2, preferably, comprises a plurality of blades 6 radiating outwardly from a control chamber 1. The blades may be contained within and supported by one or more rotatable side wall members or discs 8. An impeller element 8. comprising a plurality of spaced radiating vanes I0, is positioned within the control chamber and, preferably, fixed to rotate with the throwing blades 6. The abrasive is fed into the path of rotation of the impeller vanes l0, and is thrown with considerable velocity into the path of the outer throwing blades 6. A normally stationary but adjustable control member I of tubular form extends into the control chamber 1, and surrounds the impeller 9.' The control member II is provided with a discharge opening l2 in the side wall thereof, of limited peripheral length, through which the abrasive is thrown by the impeller vanes I0. By adjusting the peripheral position of the discharge opening in the control member, the direction of flight of the thrown abrasive can be controlled as desired.

The wheel 2 is rotatably carried by a shaft 36 journalled in bearings 31 mounted on the top wall 22, which shaft carries a pulley 38 situated between the bearings. The pulley 38 is driven from a motor 40 which drives the shaft 4| carrying a pulley 42 over which is trained a belt 43, also trained over the pulley 38. Thus, when the motor 40 is energized, the power is transmitted to the wheel 2 to drive the same and project the abrasive against the articles.

for actuating the latter, and carries a pointer which cooperates with a. scale on the face plate 58 for indicating the position of the closure member 53. If desired, the scale may be calibrated to indicate the volume flow to abrasive from the conduit 5|.

Depending from the housing 2| is the collecting trough in which is disposed a screw conveyor 6| adapted to convey abrasive from the collecting trough 60 to an eleevator 52 disposed adjacent the housing 2|. The elevator 62 comprises a pair of

drums

63 and 64 over which is trained an endless belt 65 carrying a series of buckets 56, which conveyor is driven from a motor 51 driving a shaft 68 carrying a pulley 69. Trained )ver the pulley 59 is a belt 10 which is also trained over a pulley carried on a shaft 12 driving the drum 64. The drum 53 at the boot end of the elevator is supported on a shaft. 12

- which carries a gear 13 connected by a chain 14 to a gear 15 carried on a shaft 15 extending from the screw conveyor 6 I. Upon energization of the motor 61, the screw conveyor 6| and elevator 62 are both driven, and the conveyor 5| delivers abrasive from the collecting trough 50 to the elevator 62 which, through the agency of the buckets 66, lifts the abrasive to the height of the hop per 50 and. delivers it to the hopper 50.

Mounted on structural members 18 is a thrust asoam the belt I may be adjusted by adjusting the bearing 18 of the ball type. supporting a main shaft 88, which carries a table-supporting frame 8|. The frame 8| comprises a square block 85 keyed to the shaft 88 and having secured to its four faces radially-extending arms 88 each adapted to support a pair of tables 81. The frame 8|, tables 81 and associated members constitute the supporting device 4, referred to previously.

Each of the arms 88 may be formed at its out end with a pair of bearing portions 88, each of which carries a pivot pin 89 pivotally supporting an arm 98, a bushing 9| being provided between the arm and the pivot pin 89. Each of the arms 98 is provided at its outer end with a pivot portion 93 in which is secured a pivot pin 94, on which is pivoted a depending cylindrical flange portion 95 of a table carrying a drum 98, a combined thrust and ball bearing 91 being provided between the pin 94 and the flange 95. The table 81, which is provided with a peripheral flange 98, is secured on the drum 98 by screws 99. Tables 81 may be replaced when worn. Threaded into the pivot portion 93 is a screw I85 carrying a roller I88 adapted to ride in the groove I81 of a track I88 supported on the inside of the housing a 2 I. The track I88 may take the form substantially of a rectangle, hexagon or octagon of which the alternate sides are curved and the intercarried around, and the tables 81 are moved in a generally continuous path by the arms 88. However, since the track engages the rollers I88 corresponding with each table, the axis of each table is made to follow the path defined by the track, the arms 98 swing about their respective pivots to permit the required movement of the axis of each table 81 to enable it to follow the path defined by the track I88.

The shaft 88 is driven from a motor I28 which drives ashaft I2I, carrying a spocket I22 over which is trained a chain I23 also trained over a sprocket I24 mounted on a shaft I25. The shaft I25 drives a speed-reducing mechanism which in turn drives a sprocket I21 connected by a chain I28 to a sprocket I38 carried on the shaft 88; an idler wheel I29 being provided for maintaining the tension on the chain I28.

Supported adjacent the wheel 2 is a drum I48, over which is trained an endless belt I, also trained over a drum I42 carried by a lever I43 carried by a pivot I44 secured in a bearing I45 mounted on the housing 2|. The belt MI is disposed in position, to be engaged by the peripheries of the drums 98 as they pass under the wheel 2, and to effect rotation of the drums to thereby rotate the tables whil passing through the stream of abrasive.

The rotational effect of the belt on the drums may be increased by causing the belt to travel in a direction opposite to the direction of movement of the drums. This is accomplished by driving the drum I48 from a motor I58. The motor I58 drives a pulley I 5| over which is trained a belt I52, also trained over a pulley I53 which latter pulley drives a, speed reducer I55. The speed reducer I55 drives a sprocket I58 connected by a chain I51 to a sprocket I58 mounted on a shaft I88 which also mounts the drum' I48. An idler wheel I 59 is provided for tensioning the chain I51. Upon energization'of themotor I58, the drum I48 is rotated to drive the belt I in a manner which will be apparent. The tension on position of the lever I43 which supports the drum I42.

It will be seen that the extension 23 projects beyond the main portion of the housing 2|, and is provided with an open top whereby to permit access to the tables 81 as they are moved into the extension 23. The side wall of the housing 2| is provided adjacent the hood 24 with openings I18 and "I, thus permitting clearance for the entrance into and exit from the housing of articles which are disposed on the tables 81. The openings I18 and HI preferably are closed by depending curtains I12 and I13 which prevent the escape of abrasive from the housing 2|.

Referring to Fig. 5, wherein certain essential elements of the structure of Figs. 1-4 are shown diagrammatically, it will be seen that, as the shaft 88 is rotated to carry the arms 88 around and thereby move the tables 81 around in an approximately circular path, the track I88 engages the rollers I88 to guide the tables in a generally continuous path.

The articles to be cleaned are deposited on the tables 81 as the latter move along the portion a of their path. When each table 81 moves from the portion d of its path into the portion e, its direction is changed and the axis ofeach table successively begins to move along in a straight line lying in a plane passing through the center line of the impingement pattern a: of

the stream of abrasive projected by the wheel 2. Each table 81 continues to move along the aforesaid straight line until the central portion of the table passes out of the stream of abrasive. Thus it will be seen that, during the time the table is moving along the straight line path c, all portions of the table pass through the stream of abrasive substantially the same number of times. However, since the outer portions of the table are moving at a higher lineal speed than the central portions, they are not within the stream of abrasive for as long a period as the central portions nearer the axisof the table. Hence the articles on the outer portions of the tables are not subject to the abrasive effect of the stream for as long a period in any one revolution as the articles in the inner portions.

This result is compensated for by the fact that the outer portions of each table enter the abrasive stream before the central portion and continue to rotate in the stream after the central portion has passed from the stream. Hence the articles contained on the outer portions of the table are subjected to the effect of the stream of abrasive for a greater number of revolutions than the articles on the central portion of the table. By properly selecting the speed of travel of the table through the abrasive stream and the speed of rotation about its axis, a substantially uniform treatment of all of the articles on the several portions of the table can be effected. In this embodiment of the invention, as well as in the others disclosed herein, the stream s of abrasive projected by the wheel 2 spreads fanwise from the wheel, as shown diagrammatically in Fig. 11. It will be seen that the abrasive-at the entrance end of the stream s strikes the tables 98 at a considerable angle 0 to the vertical. The angle of impingement varies continuously until finally at the departure end of the stream s the abrasive strikes the .tables 98 at a larger angle to the vertical, on the opposite side of the vertical from the angle 0. Since the tables 98 are continuously turned about their respective axes while in the stream, all sides of the articles q supported on the tables 88 are struck by abrasive from angles varying throughout a range corresponding to the range of angles between and Hence, not only the top surfaces but all side walls and cavities, depressions and the like are subjected to the action of the abrasive, and are treated in a thorough and complete manner.

During the movement of the tables along the portion 71. to b of the path. they are in the extension 23 of the housing, which extension has an open top, as described above, and access may be had thereto for the purpose of depositing on the tables articles to be treated and removing articles which have been carried through the abrasive stream.

The structure disclosed in Figs. 1 to 4 may be modified slightly, as indicated diagrammatically in Fig. 6, the structural details being generally similar to those in the aforementioned figures. In this construction, a shaft 200 carries a triangular block l which supports three radially-extending arms 202. Pivoted to each arm at its outer end is a pair of levers 203, each of which supports a table 204, in a manner similar to that previously described, through the agency of a drum 208. Each drum 206 carries a roller 201 which cooperates with a track 208 for the purpose of guiding the tables along a predetermined generally square path, 1' to p, the corners g, l, n and p of which are slightly rounded to permit the rollers 201 to pass therearound.

Adjacent one side K of the track 208 is a rotating mechanism, comprising drums or rollers 209 and H0 from which is trained a belt 2i i. The drum 209 is suitably driven to carry the belt 2 along in a manner similar to that described in connection with the belt Mi (see Fig. 1). A similar rotating arrangement 2l2 is disposed adjacent the side 0 directly opposite the side It, and cooperates with the drums 206 in a similar manner.

Disposed above the sides It and o of the track 208 are abrasive-projecting wheels 2 and 2I5, respectively. These wheels may be of similar construction to the wheel 2 (see Fig. 2), and are each disposed in position to project a stream of abrasive against the upper surfaces of the tables 204 as they move along the track 208. The wheels 2" and 2|5 are each mounted in a position inclined relatively to the track 208 so as to project the abrasive in a stream having impingement i' patterns 1 2, which have their longitudinal centerlines inclined to the path of movement of thetables 204.

It will be seen that, by reason of the arrangement of the wheels 2 and 2l5, the peripheral portions of each table pass through the stream of abrasive a greater number of times than the central portions thereof. It will also be noted that the peripheral portions of the table are moving at a greater lineal speed than the central portions, and hence pass more rapidly through the stream than the central portions. The total time during which the several portions of each table are within the stream may be made approximately equal by so positioning the wheels that the peripheral portions of the table pass through the stream a sufiicient number of times so that the total time of exposure to the stream equals the time the central portions are in the stream. Thus, all portions of an article or articles supported on the tables are subjected to the same amount of abrasive treatment. It will be obvious that by varying the angle at which the wheels are disposed relative to the track, the time that any portion of a table is within the stream may be adjusted and all portions of the table may be subjected to the same amount of treatment or to any desired proportionate amount of treatment.

The provision of two wheels permits the complete treatment of all surfaces of articles during the course of a single trip around the path. The articles may be deposited on the tables 204 during their respective movements along the portion i of the path, then treated on one side during the movement along the portion k. During movement along the portion m, the articles may be turned over and then treated on the other side.

while moving along the portion 0.

Where it is desired to treat a number of articles, all of which are the same or of generally similar shape and form, it is often desirable to provide a larger number of tables than provided in the constructions hereinbefore described, and it is often desirable to provide a separate table for each individual article. Such apparatus is especially to be desired in treating articles such as ring gears.

A construction suitable for such use is disclosed in Figs. 7 to 10 wherein the constructional details of the apparatus preferably are generally similar to those previously described, only the essential differences being expressly described and pointed out hereinafter.

A suitable housing 30I is provided, and supports on its upper wall a rotatable abrasivethrowing wheel 302 driven from a motor 304 through a driving mechanism 305. An elevator arrangement 306 is provided for conveying used abrasive from a hopper 301 at the lower portion of the housing 30l to a feed hopper 308 disposed above the wheel 302.

Mounted in a thrust bearing 309 at one end of the housing is a vertical shaft 3! carrying a drum 3! l, and a similar shaft 3|2 mounted near the opposite end of the housing supports a drum 3l3. Trained over the drums is an endless belt 3. to which is suitably secured a series of vertical pivot members 315, each of which supports rotatably at its upper ends a table 3l8 having a drum portion 3H.

The ends of the shaft 3|2 are journalled respectively in bearings 3|8 and 3l8 adjustably mounted on the top wall and bottom wall respectively of the housing 30L The positions of the bearings M8 and 3|8 may be individually adjusted by adjusting mechanisms 3i!) and 3l9 cooperating respectively with the bearings M8 and 3i8 The tension in the belt 3" may be varied by suitable operation of the adjusting mechanisms to move the bearings M8 and 3UP, and consequently move the shaft 3I2 toward or away from the shaft 3l0.

The drum 3 is driven from a motor 3I'I, which drives a sprocket 320 connected by a chain 32l to a, second sprocket 322. The latter sprocket 322 drives a speed reducer 323 which carries a sprocket 324 connected by a chain 325 to a sprocket 328 mounted on a shaft 3l0. Thus, upon the energization of the motor 3", the drum 3 is rotated and moves the belt 314 in an endless elongated path.

Rotatably supported in the side wall of the housing 30l is a shaft 329 carrying a drum 330 over which is trained an endless belt I which .adjusting mechanism 335.

The drum 330 is driven from a motor 340 which drives a pulley 34! over which is trained a belt 342 extending to a second pulley 343 which drives a speed reducer 344. The speed reducer 344 drives through a sprocket 345 and a chain 346 to ya sprocket 34! carried on the shaft 329. Upon energization of the motor 340, the drum 330 is rotated and moves the belt 33! along a path wherein the upper length of the belt engages the drum portion 3H of each of the tables 3I6 which lie on one side of the endless path of the tables.

On the side of the housing opposite the abrasive wheel 302 is provided an opening 35!) whereby access may be had to the tables as they pass along this side of the housing. A pair of curtains 35! and 352, a generally vertical baflle 353, slanting baffle 354 and a horizontal baflle 355 may be provided for preventing the escape of flying abrasive from the housing 30!. Thus, when the tables pass along the front of the housing, access may be had to the tables for the deposit and removal of articles to be treated, without danger to the operator, and without the escape of flying abrasive from the housing.

Another baflle 355 is provided adjacent the stream of abrasive from the wheel 302, to further confine the abrasive, and bafiles 35'! depend from the top wall of the housing on either side of the wheel. Baflle 358'is provided above the endless belt 33! to protect the latter from the wearing effect of the abrasive particles.

Various modifications may be made in the construction of the apparatus, as will be apparent to those skilled in the art.

Since the tables are not continuously in the abrasive stream, but are moved successively into and out of the stream, the wheel or wheels need not be halted during loading and unloading, but may be operated continuously. By using a plurality of tables, articles are continuously being subjected to the stream of abrasive, and the moving stream of abrasive is thus utilized to the maximum extent.

Since the articles are disposed on and removed from the tables at a point remote from the stream of abrasive, and since the moving abrasive stream is entirely enclosed, there is no danger of the operator being injured by flying particles of abrasive. Since the tables do not individually rotate when they are in the vicinity of the opening in the housing, the articles may be handled more or less leisurely and carefully, thus greatly reducing the. liability of breakage of the articles and injury to the operator from the dropping of articles due to careless or hurried handling.

The drives for the wheel, the support and the abrasive-conveyor mechanism are simple and rugged, and are of such construction that they all may be driven from separate sources of power, as shown in the illustrative embodiment. The

provision of separate drives has certain a dvan-,

tages in that any one may be stopped, started, retarded or accelerated in accordance with opera tive requirements, as will be understood.

An advantage of the present invention is that it is adaptable to treat articles which have complex and irregular shapes, which require equal or predetermined, unequal exposure of various surfaces to the abrasive stream, and other types of articles which are fragile or which cannot be treated suitably where prior types of supporting devices are employed.

Inasmuch as the tables may be made so as to be readily removable from the support, various shapes and sizes of tables may be substituted to accommodate articles of varying sizes and shapes. Although, generally, the articles will be placed upon the tables and will be retained thereon due to their own weight, yet in some instances it may be desirable to provide tables of such shape as to fit the articles to prevent shifting of the articles on the tables, or clamps may be provided to ensure that articles are retained on the tables.

While certain novel features of the invention have been disclosed and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

1. Apparatus for blast treating metallic articles, including in combination, eans including a rotary centrifugal wheel fort rowing a stream of abrasive in a divergent path having an elongated impingement pattern, a rotatable shaft, a supporting member fixed to said shaft, a table adapted to support the article to be treated, means including a swinging arm for swingably and rotatably mounting said table on said supporting member, driving means for rotating said shaft to rotate said supporting member and thereby impart a translatory movement to said table through said stream of abrasive, driving means for rotating said table about its axis during at least that portion of its translatory movement when said table is carried through said abrasive stream, and means for guiding said table during its translatory movement along a path extending generally longitudinally of the elongated axis of the impingement pattern of said stream of abrasive.

2. Apparatus for abrasively treating articles including in combination, a housing, means for projecting a stream of abrasive into said housing, a supporting frame, means for rotating said frame, a plurality of arms swingably connected to said frame, tables rotatably supported on said arms, means including a track cooperating with said arms for guiding said tables during rotation of said frame along a predetermined path extending through said housing, and means adjacent at least a portion of the path of travel of said tables for rotating the same on said arms.

3. Apparatus for abrasively treating articles including in combination, an abrasive projector for projecting a stream of abrasive, and means for carrying articles to be treated through said stream and for simultaneously moving them about in the stream, said means including a rotatably mounted frame, means for rotating said frame, a series of article supports, a track cooperating with said supports to guide them along a predetermined path, links swingably connecting said supports to said driven frame, and means for rotating each of said supports about its own axis.

4. Apparatus for treating metal articles including in combination, means for projecting a stream of treating particles, a series of supporting tables, a frame, means for rotatably rounting said frame, a track for guiding said tables along a continuous path having a portion thereof extending adjacent said stream, an arm rotatably supporting each table and swingably connected to said frame to permit said tables to follow said continuous path, means for rotating said frame to advance said tables through said stream, and means for rotating said tables about their individual axes.

5. Apparatus for abrasively cleaning metal articles including in combination, an abrasive throwing wheel for projecting abrasive in a stream having an elongated impingement pattern, and means for conveying articles through said stream longitudinally of said impingement pattern, said conveying means including a plurality of spaced drums each mounted for rotation about a vertical axis, an endless flexible belt trained around said drums, a plurality of individual article supporting work tables, means rotatably mounting said work tables on said flexible belt, and means adjacent at least a portion of the path of movement of said flexible belt operative independently of the speed of advance of said supporting tables for rotating said individual work tables during passage through said abrasive stream.

6. Apparatus for abrasively cleaning metal articles including in combination, means for establishing a stream of abrasive, and means for conveying an article to be cleaned through said stream, said conveying means including a frame, means mounting said frame for rotation, an arm pivoted on said frame, a work holder carried by said arm adjacent the free end thereof, and means engageable with said arm adjacent the free end thereof for guiding said work holder along a non-circular path as said frame is rotated.

7. Apparatus for blast cleaning metallic objects including in combination, an abrasive throwing asoaasa wheel operative to project a fan-shaped stream of abrasive having an elongated impingement pattern, means for controlling said stream to direct the same in a'downwardly direction, a rotatable frame, a plurality of article-supporting tables rotatably mounted on said frame, mechanism for rotating said frame so as to move said tables successively in a linear direction under and through the abrasive stream, mechanism operative independently of said frame moving mechanism for rotating said tables as they pass through the abrasive stream, said mechanism being operative to rotate-said tables for a limited distance only during their linear travel, and means for guiding said tables along a substantially straight line during the passage of said tables through the stream.

8. Apparatus for blast cleaning articles including in combination, supporting tables for articles to be treated, means for linearly advancing said tables along a predetermined path having a straight line portion, means operative independently of the advancing speed of said supporting tables for rotating said tables during travelv thereof along the straight line portion of said path, an abrasive throwing wheel for projecting a fan-shaped stream of abrasive having an elongated impingement pattern, and means rotatably mounting said abrasive-projecting wheel in a position to project the abrasive in a stream having the longitudinal axis of its impingement pattern extending in the general direction of the straight line portion of the path of advance of said tables.

VERNE E. MINICH.