US2275434A - Centrifugal blasting machine - Google Patents

Description

March 10, 1942. L; L. HoBsoN CENTRIFUGAL BLASTING MACHINE FiledAug. 21, 1959 6 Sheets-Sheet 2 INVENTOR Zig/d Z. amn Maf/5% azi-A ATTORNEY March 10, 1942. L. L. HoBsoN CENTRIFUGAL BLASTING MACHINE' I Filed Aug. 21, 1959 6 Sheets-Sheet 5 INVENTOR MEN "mm N v NN NSN March 10, 1942.3'

L. L. HoBsoN CENTRIFUGL BLASTING MACHINE Filed Aug. 21, 1959 6 Sheets-Sheet 6 INVENTOR ATTORNEY Patented Mar. 10, 1942 v 2,275,434 CENTRIFUGAL BLASTING MACHINE Lloyd L. Hobson, Marshall, Mich., assignor to The American Foundry Equipment Company, Mishawaka, Ind., a corporation of Delaware Application August 21, 1939, Serial N0. 291,111

19 Claims. SCI. 51-9) This invention relates to centrifugal blasting machines, and more particularly to an improved blasting machine of the centrifugal type from which abrasive can be fired in any desired controlled clockdial direction and concentrated in any desired work zone.

In accordance with this invention, an abrasive throwing rotor is fixed to a suitable drive shaft which is driven in timed relation to the shaft of a control runner positioned within the rotor. The rotor may comprise a suitable rotor head equipped with any desired number of equally spaced throwing blades or segments which define abrasive discharge passageways or ports therebetween. 'I'he throwing blades or segments may be removably mounted upon the rotor head in such manner that they may be easily replaced when worn. The throwing blades or segments of the rot-or may be of any desired radial length, stopping short of the axis of rotation thereof a sufficient distance only to provide room for the control runner seating therein.

The control runner may comprise a suitable runner head fixed to a drive shaft provided therefor, the runner` head being likewise equipped with equally spaced abrasive discharge blades or segments defining abrasive discharge passages or ports therebetween. The blades or segments of the control runner may also be detachably secured to the runner head so that they may be removed and replaced when worn. The blades or segments of the control runner may be of any desired radial length, but preferably the inner ends thereof should stop short of the axis of rotation of the runner to provide a central space into which abrasive may be fed from a suitable abrasive supply conduit. The axis of rotation of the control runner is concentric with the axis of rotation of the throwing rotor, both the throwing rotor and control runner being driven in predetermined timed relation and preferably from a common drive connected to a suitable source of power, such as an electric motor.

The number of passages or blades provided on the control runner should be either greater or less than but not equal to the number of blades or discharge passageways provided on the throwing rotor. Where it is desired to obtain directional discharge over one section of the rotor only, the number of blades or discharge passages in the control runner is preferably either -one less or one more than the number of blades or discharge passages in the throwing rotor. The rotor shaft and runner shaft are operably conso that a drive ratio between these two shafts which is in inverse ratio to the number of blades or disch-arge passages in the runner and rotor is at all times maintained. Assuming, for example, that the rotor is provided with eight throwing blades or discharge passages and the runner is provided with nine blades or discharge passages, and assuming further that an effective blasting speed can be attained with this machine when the rotor is rotated at 2250 R.. P. M., the runner should then be rotated at 2000 R. P. M. If this inverse ratio is at all times maintained, the blades or abrasive discharge passages in the runner can be moved into discharging alignment with the discharge blades or passages in the rotor at a predetermined clockdial position, so that the machine will iire the abrasive over a predetermined clockdial sector during rotation thereof. When it is desired to discharge the abrasive from two sections of the rotor, the number of blades or discharge passages in the control runner is preferably either two less or two more than the number of blades or discharge passages on the throwing rotor so that the blades or discharge passages in the control runner and throwing rotor will move into discharging alignment at two positions, as, for example, the 12 oclock and the 6 oclock positions. The necessary fixed drive ratio between the rotor shaft and runner shaft can be maintained by positive interconnecting drives between these shafts and. rotating both shafts from a common power source. The drive transmis- -sion between the rotor shaft and runner shaft may take the form of intermeshingv gears, chain and sprocket drives, Morse drives, or any other positive drive mechanism which will maintain the required drive ratio. The equally spaced discharge passageways in the runner may take the form of simple outlet ports formed in the tubular side wall of a tubular member. The discharge passages in the rotor may likewise comprise discharge ports formed in a relatively thick rotor ring, but preferably the throwing face of these discharge ports should be of sufficient length to receive abrasive thereon and forcibly ixnpel the abrasive forwardly during rotationfof the machine at a blasting velocity.

The throwing rotor, as well as the control runner, may be made in numerous different shapes and forms within the purview of this invention. The blades, throwing segments, discharge passages or discharge ports, in the rotor and runner may be made of almost any desired radial length and almost any desired number thereof may be nected by means of a suitable drive transmission 65 provided ranging from one to fty or more. Substantially the only essential criterion that must be followed is that the blades or segments, passages or ports in the control runner must be either more or less than the blade segments. passages or ports in the throwing rotor and, further, that the runner and rotor must be driven in substantially positive timed relation so that the abrasive discharge passages or ports in the runner will advance ahead or drop back into alignment with the discharge passages or ports in the rotor at the predetermined clockdial position or positions during timed rotation thereof to eect the desired directional discharge of the fired abrasive.

Directional control adjustment can be efected by readjusting the position of the runner on its drive shaft, by readjusting the position of the rotor on its drive shaft, or by readjusting the sprockets, gears, or other positive drive mechanism that operably connects the runner shaft with the rotor shaft.

By reason of the fact that the runner rotates at only slightly less or slightly greater speed than the rotor and in the same clock-dial direction, abrasive transfer from the runner to the rotor can be effected substantially without shock or impact to the advancing faces of the rotor blades or segments. Thus abrasive wear on the inner ends of the advancing rotor blades or segments is at a minimum and little or no break-up or destruction of the abrasive results during its passage through the machine. The machine is so constructed that the abrasive is distributed unlformly over the entire width of the rotor blades or segments, producing even and uniform wear thereon with correspondingly greater life thereof, and, finally, an impingement pattern of. full rotor blade width is produced. Directional iiring of the abrasive ejected from the rotor may be controlled to a great nicety and within or less, if desired. Little or no scattering of the abrasive around the undesired sections of the rotor results. An unusually high degree of directional control is produced. The length of the blast pattern may be varied by enlarging the circumferential length of the passages in the rotor or runner or both. With corresponding enlargement of the passages in the runner and rotor which lengthens the impingement pattern, a

greater quantity of abrasive can be thrown, so

that substantially uniform abrasive intensity throughout the length and width of the impingement pattern is also attained, even though a relatively long impingement pattern is made. This highly important result has never been attained in centrigugal-blasting machines now known or l in use. The machine runs smoothly and silently, maintains excellent dynamic balance, and will clean and treat the surfaces of castings, forgings, bars, sheets, and other like hard surface materials, with high efficiency and at low cost.

.An object of this invention is to provide a centrifugal blasting machine having improved means for controlling the direction of discharge of abrasive fired therefrom.

Another object of this invention is to provide a centrifugal blasting machine in which wear on the operating parts thereof by reason of contact with moving abrasive is reduced to a minimum, with substantially no break-up, destruction or damage of the abrasive resulting during its passage through the machine.

Another object of this invention is to provide a centrifugal blasting machine in which directional firing of the thrown abrasive can be con- 7| trolled to a nicety and which can be made to produce a blast pattern on the target of any'desired width and length, which pattern is characterized by uniformity in blast over the entire surface thereof.

Other objects and advantages of this invention will become apparent as the disclosure pro- The invention also consists in certain new and original features of construction and combination of parts hereinafter set forth and claimed.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which- Fig. 1 is a side elevational view of one form of improved abrasive throwing machine showing the mountings and drives for the throwing rotor' and control runner, certain Darts being shown in section to illustrate the construction;

Fig. 2 is a front face view of the throwing rotor and control runner as it appears when looking in the direction of the arrows 2-2 of Fig. 1

Fig. 3 is a cross-sectional view through the throwing rotor and control runner as it appears when looking in the direction of the arrows 3-3 of Fig. 1;

Fig. 4 is a transverse cross-sectional view through an abrasive throwing machine. showing a throwing rotor and control runner with drives therefor of somewhat modified construction;

Fig. 4a is a cross-sectional view showing certain details of the driving mechanism for the throwing rotor and control runner, this view being taken along line la-la of Fig. 4.

Fig. 5 is a front face view of the throwing rotor and control runner as it appears when looking in the direction of the arrows 5-5 of Fig. 4, certain parts being broken away to illustrate certain features of the construction;

Fig. 6 is a transverse cross-sectional view through an abrasive throwing machine, showing a throwing rotor and control runner and drives therefor of further modified construction;

Fig. 7 is a cross-sectional view through the throwing rotor and control runner as it appears when lgoking in the direction of the arrows l-l of Fig.

Fig. 8 is an enlarged transverse cross-sectional of Fig. 6;

Fig. 9 is a perspective view of a throwing blade which may be associated with the throwing rotor shown in Fig. 6;

Fig. l0 is a cross-sectional view through a throwing rotor and control runner of the type shown in Figs. 6 and 'I modiied to the extent that the control runner is provided with discharge passages arranged to align with discharge passages of the throwing rotor at two diametrically opposed points during operation whereby two oppositely directed streams of abrasive will be simultaneously red by the machine; and

Fig. 1l is a cross-sectional view through a throwing rotor and control runner of the type illustrated in Figs. 1, 2 and 3, `except that the control runner is provided with discharge passages which align with dlscharge passages inthe throwing rotor at two diametrically opposed points during operation of the machine whereby abrasive may be fired from the machine in two directions simultaneously during the operation thereof.

Similar reference characters refer to similar parts throughout the several views of the drawings and specification.

Referring more particularly to Figs. 1 to 3 inclusive, a throwing rotor I is illustrated fixed to shaft 24, rotated by pulley 30 operatively connected to a suitable source of power, as an electric motor, by means of a V-belt drive. A control runner 40 mounted upon a shaft 55 is operatively connected to be driven in timed relation with shaft 24, and rotor I0. As. more particularly illustrated in Fig. 3, the throwing rotor I0 isprovided with a plurality of equally spaced abrasivedischarge passageways I5, which are shown for purposes of illustration as sixteen in number. The control runner 40 is also provided with equally spaced abrasive discharge passages l45 which may be greater or less in number than the discharge passages I in the throwing rotor but shown in Fig. 3, for purposes of illustration only, as seventeen in number. 'Ihe speed of rotation of the control runner 40 with respect to the throwing rotor III is such that the discharge passages therein will rotate into alignment in the desired clock-dial position so as to eiiect controlled directional firing of the abrasive ejected from the throwing rotor I0. Y

The throwing rotor I0, as shown in Figs. 1 to 3 inclusive, may comprise a side wall member or rotor head I I having a plurality of blades or segments I2 mounted on the periphery thereof, which are spaced apart so as to provide abrasive discharge passageways I5 therebetween through which the abrasive may be freely discharged. The blades or segments I2 may have any desired radial length short of the axis of rotation of the throwing rotor, so as to provide a central space within which the control runner 40 may be positioned. The throwing blades of segments I2 may be cast as a part of the side wall vmember II or they may be suitably secured thereto so that the blades may be removed when worn, as desired. A ring member I3 is provided which is connected to the free ends of the blades or segments I2, as by screws I4, to stiffen and strengthen the construction.

Assuming that the throwing rotor I0 and control runner 40 is to be rotated in the direction of the arrow shown in Fig. 3, each blade or segment I2 is provided with an advancing throwing face I5 and a following face I5, so that the advancing face I5' and following face I5" of blades or segments I2 define an abrasive passage I5 therebetween. Each blade or segment I2 may also be provided with an abrasive-retaining cavity I8 defined between abrasive-retaining end wall portions I1 and I8, for a purpose that will presently appear.

The throwing rotor I0 is fixed to a hub member 20, as by securing bolts 2I screwed into the side wall member I I thereof. The hub is provided with an internal bore 22 into which thel end of drive shaft 24 extends, the hub 2i) being secured to drive shaft 24 as by spline 23. The shaft 24 is rotatably mounted in spaced bearings 25, each supported by suitable supporting frames 28 and 21 respectively. Each bearing 25 is held in fixed position by means of a bearing cap 28 bolted to each supporting frame, as by bolts 29. The shaft 24 and the throwing rotor III is rotated at the proper dired driving speed by means o. the V-belt pulley I5 fixed to the drive shaft 24.

The control runner may comprise a side wall member or runner head 4I, which is positioned within the central space within the throwing rotor I0. Blades or segments 42, deflning abrasive discharge passageways 45 therebetween, may be integrally formed with the side wall member 4I or may be removably secured thereto in any desired manner. The front face of the control runner is substantially closed by a side wall plate 43 secured to each of the blades or segments 42, as by screws 44. The closure plate 48 is provided with an axially extending aperture 53 therein through which drive shaft 55 for the runner head extends and through which aperture abrasive a, supplied by the feed funnel 8i, may be injected into the central space 54 between the side wall member 4I and the closure plate 43 of the control runner 40.

'I'he inner face and the passage-defining walls oi' the blades or segments 42 may be covered with a liner of abrasive resistant material. as shown more particularly in Fig. 3, each liner having an inner facing portion 48 and passage liner portions 41 and 48. The liner portion 41 defines the advancing face of the blade or segment and the liner portion 48 denes the trailing or following face thereof. Each blade or segment 42 may be provided with an outwardly facing cavity 49 defined between retaining end walls 50 and 5I.

The side wall member 4I of the control runner 40 may be provided with an axially extending internal hub portion 52 through which the drive shaft 55 extends. The hub portion 52 may have a generally cone-shaped contour so as to deflectv the abrasive discharge into the control runner 40. 'Ihe hub portion 52 is secured to the drive shaft 55 by means of a suitable spline 56.

'I'he reduced end 55' of shaft 55 extends into the hub 29 of the throwing rotor I0 and is rotatably mounted therein by means of a suitable bearing which may comprise bearing raceway member 58 fixed to the reduced end 55' of shaft 55. Roller bearings 59 roll in raceway member 58 and a raceway member 60 fixed to the interior of hub 28. The shaft bearing may be held in position by means of a cap plate 5I screwed into the hub 20, as shown in Fig. 1. The end of shaft 55 extends through a suitable opening 51 i1. the side wall member II of the throwing rotor I Il and is supported in the bearing housed within the hub 20. The other end of the shaft 55 is rotatably supported in a suitable bearing 83 carried by supporting frame 84, the shaft 55 being held in position by a bearing cap removably secured to the frame support 64 by bolts 66.

The control runner shaft 55 may be operatively connected to be rotated by the drive pulley 30, as by means of a sprocket 81 fixed to shaft 55, over which is trained a drive chain 68 trained over transmission sprocket 89. Transmission sprocket 59 isfixed to the end of a power transmission shaft 10 supported in spaced bearings 1I, each supported upon a. suitable bracket support 12. The shaft 10 and its bearings 1I( are held in operative position by means of bearing caps 13 secured as by bolts 14 to their respectivesupporting brackets 12. The shaft 10 is 'provided with-a suitable drive sprocket 18 secuiezdg'to the opposite end thereof, over which is trainedv a drive chain 19 yextending around sprocket'80 fixed to the shaft 24 of the throwing-rotor I0. By means of the drives above provided, it `will be appreciated that both the throwing rotor I0 A control runner Il and the control runner Il may be driven simultaneously and in synchronised relationship from the drive pulley 2l.

Abrasive is supplied to the interior space Il of the control runner by means oi an abrasive supply pipe or chute Il having a col1ar l2 extending into the opening I3 in the front wall plate 43 of the control runner 40. The lower arcuate portion II of the collar portion l2 may be inclined downwardly to permit the abrasive a to smoothly slide into the abrasive-receiving interior 5I of the control runner Il. 'I'he feed spout 0I may be suitably supported in nxed position by means of a bracket Il connected to the feed spout Il and suitably secured to a stationary bracket or frame member "positioned exterior of the control runner 4l.

It will be appreciated that the abrasive fed into the interior I4 of the control runner-Il falls downwardly by the action of gravity into the discharge es ll of the control runner I0 during rotation thereof. The abrasive driven outwardly by centrifugal force occupies the in-,

terior of the discharge passages 4l and additional abrasive which cannot occupy the nlled passages Il clings. through the action of the centrifugal force. to the interior wear surfac of the throwing blades or segments 42.

The abrasive driven outwardly by centrifugal force into the discharge passageways Il of the control runner Il, will also iill the cavities Il provided at the inner periphery of the throwing segments I 2 during rotation of the runner Il.

Y The relative speed difi'erential between the throwing rotor l0 and the control runner Il is small, so that no excessive friction'is set up between the inner periphery of the blade segments I2 of the throwing rotor l0 and the outer periphery of the blade segments 42 of the control runner l0. The pockets I0 in the blade segments I2, which are normally illled with abrasive during operation, and the pockets Il of the blade segments 42, which are normally free of abrasive be cause of the outward drive of the centrifugal force exerted on the abrasive, have a marked effect in reducing frictional wear between the moving blade segments i2 of the throwing rotor Il and control runner 4l and further prevent discharge of abrasive from the throwing rotor il in undesired directions.

The control runner and the throwing rotor Il are driven at such differential speeds as to cause the discharge ways I5 and il thereof to move into alignment to permit discharge of the abrasive through the aligned eways 4l and I 5 at a predetermined clock-dial position. This is'iected by rotating the control runner Il andthrowing rotor I0 at e speed diiferential which is determined by the relative number oi' discharge passageways I5 and i5 therein. 'Ihe discharge passageways l5 and 4l in the throwing rotor i0 and control runner 40 may be almost any desired number except that the control runner Il must either have more or less discharge es than the number of discharge passages in the throwins rotor Il.

By way of example,

thereisshowninFig.3a having seventeen equally spaced discharge eways 4I therein, while the throwing rotor Il has sixteen equally spaced discharge peways Il therein. It will be appreciated that if the throwing rotor il, equipped with sixteen discharge passages II, is rotated at 1700 R. P. M. and the control rlmner Il,

tated at 1000 R. P. M., the respective es Il andllthereofwillmoveintoalignmentata predetermined clock-dial position, so as to permit discharge of abrasivev through the aligned openings. The advancing faces il' of the rotor blade ts l2 operate to hurl or throw abrasive approximaiely tangentlally from the periphery of the rotating throwing rotor Il. This speed differential may be obtained by making the sprocket; 1l and Il, which drive the control runner shaft II. of the proper relative tooth ratio to effect this result. Since the speed diiferential between the control runner Il and the throwing rotor I l, in the machine disclosed in Fig. 3, may beonly100R.P.M.,noseriouswear-onthead jacent faces oi' the moving blade segments of the control runner Il and throwing rotor il results.

It will be appreciated that both the outside and inside diameters oi' the throwing rotor Il may be of any size desired, the outside diameter of the control runner Il being correspondingly reduced or enlarged. Thus, the throwing faces i5' of the blade segments i2 may be of any desired length to effect projection of the abrasive at the desired blasting velocity, the speed of rotation of the throwing rotor Il as well as its diameter being such as to give the abrasive thrown therefrom the desired blasting speed.

The direction of discharge from the throwing rotor Il may be controlled by so adjusting the position of the discharge passageways 45 of the control runner 4l that one of the passageways I5 will move into alignment with one of the discharge es Il of the throwing rotor Il as that discharge e arrives at the desired clock-dial position, which may be eiected by shifting the or by shifting the equipped with seventeen discharge passageways 4l. is ro- 75 their respective shafts.

'Ihe throwing rotor il desired blasting speed, the rotating speed of the being correspondingly timed to eilect alignment of the respective passages thereinl at the selected clock-dial position. Full, complete and positive control of the direction oi' discharge of the thrown abrasive and high blasting emciency with relatively little wear on the parts, is obtainable by the machine above described. l A centrifugal abrasive blasting machine oonstructed in accordance with this invention may otheriormsthanthatshowninFigs. 1 to3 inclusive. For example, there is shown in Figs.

passageways |05 defined between blade segments il2 of greater radial the throwing rotor il shown in Fig. 3. The control runner IIO, as shown in Figs. 4 and 5, positioned within the throwing rotor Ill, is of correspondingly reduced diameter and is provided with discharge eways |36 denned between sector-shaped blade vsegments |32. The throwing rotor III may be fixed to a hollow shaft IIS rotatably mounted upon suitable bearings, and the control runner |20 may be iixed to a solid shaft l2! extending through hollow shaft shafts being operatively connected by means of suitable gearing contained within a gear housing ISI. A pulley wheel |23, over which may be trained a V-belt drive, is iixed to the hollow shaft I" by means of a suitable spline |24. so

may be rotated at any length than that shown in that both the rotor shaft ||6 and the runner shaft |33 may be rotated in proper synchronized relationship from` a single power source.

The throwing rotor may comprise a side wall member |0| upon which the throwing blades or segments |02 may be removably mounted. There is shown in Fig. 5, for purposes of illustration, eight blades or Segments |02 equally spaced apart to provide abrasive discharge passages |06 therebetween. A closure ring or cover plate |03 may be provided to close the front face of the throwing rotor |00; face plate |03, the throwing blades |02 and side wall member |0| being suitably secured together as by threaded bolts |04. The interior surface of the side wall member |0| and the closure member |03 may be provided with suitable grooves to receive and maintain the blades or segments |02 in proper spaced relationship.

Assuming that the throwing rotor |00 and control runner |30 rotate in the direction of the arrow shown in Fig. 5, the advancing face |01 of each blade or segment |02 provides an abrasive throwing face or surface over which the discharging abrasive moves, the following face |08 of each segment along with the advancing l face |01 of the following segment dening the abrasive discharge passage |06 therebetween. The faces |01 and |08 of each segment |02 and the abrasive discharge passages |06 may be of any desired radial length, extending inwardly a sumcient distance short of the axis of rotation of the rotor |00 to provide only sufdcient space for the control runner |30.

'I'he inner peripheral surface of each throwing segment |02 is provided with an inwardly facing cavity |03 defined by end riser, walls ||0 and adjacent each discharge passageway |06. Abrasive a is free to collect in the cavity |03 but due to the riser walls ||0 and will not discharge into the discharge passageways |06 until abrasive is supplied to the discharge passageway |06 in the throwing rotor |00 at the desired pre.- determined clockdial position when abrasive passages |36 of the control runner |30 move into alignment therewith, as will be presently described.

The throwing rotor |00 is mounted upon a suitable hollow hub ||4 and secured thereto by bolts ||5 screwed to the side wall member |0|. 'I'he hollow rotor-supporting shaft ||6 extends into the hub bore and is secured thereto by means of a suitable spline 'I'he hollow rotor shaft I6 is supported by a pair of suitable spaced brackets |8 and ||3 each having one or more ball bearing mountings for the shaft ||6, comprising raceway collars fixed to the shaft ||6, raceway collars |22 carried by its supporting bracket, and ball bearings |2| which move in the raceway collars |20 and |22.

The control rlmner comprises a side wall member |3| supportingV-shaped blade segments |32 which are equally spaced to provide therebetween nozzle-shaped abrasive discharge passageways |36 defined by the advancing face |34 of one segment |32 and the following face |36 of the preceding segment |32. The blade segments |32 may be integrally formed with the side wall member |3| or may be removably secured thereto by suitable bolts or screws. The control runner |30 lits within the throwing rotor |00, and the open face thereof may be closed by a suitable closure plate |33 formed integrally with or otherwise secured to the blade segments |32.

The apex end of the blade segments |32 extend inwardly short of the concentric axis of rotation of the throwing rotor |00 and control runner |30, and front closure plate |33 is provided with a suitable opening |31 into which the discharge end of abrasive supply spout |60 extends. Abrasive a is discharged from the discharge spout |63 into the central space |33 within the control runner |30 where the abrasive collects and is driven by centrifugal force into th discharge eways |36 thereof.

The control runner |33 is ilxedly mounted upon a suitable shaft |33 extending through the hollow rotor shaft ||6, the reduced end |40 of shaft |33 extending into a cup-shaped hub portion |4| which may be formed as an integral part of side wall member |3|, the reduced end |40 of the shaft being secured to hub portion |4|, as by spline |4|'.

The runner end of the shaft |33 is rotatably supported within the hollow shaft ||6 by means of a suitable bearing comprising raceway collar |42 xed to the shaftl |33, raceway collar |44 fixed to the hollow interior of rotor hub ||4, raceway collars |42 and 44 having ball bearings |43 rollable therebetween. The shaft |33 may be provided with an enlarged boss portion |45 to retain the bearing in proper position. The opposite end of shaft |33 may be likewise supported by a suitable roller bearing comprising raceway co1- lar |43 ilxed to shaft |33, raceway collar |48 xed to the interior of hollow rotor shaft ||6 with roller bearings |4'| in position to roll between these raceway collars.

Means are provided for. operatively connecting rotor shaft I6 to rotor shaft |33 so that they can be driven in the proper timed relationship. As shown more particularly in Figs. 4 and 4a, a driving gear is xed to the end of rotor shaft ||6, which driving gear meshes with transfer gear |56 xed to shaft |31. Shaft |51 is free to rotate in suitable bush bearings |53 and |63 provided respectively in a gear casing |58 and a gear casing enclosing plate |6|. A transfer gear |64 also fixed to rotating spindle shaft |51 is arranged to mesh with gear |65 fixed to the end of the runner shaft |33. The gear housing |58 may be provided with a suitable flange by means of which it may be secured to the adjacent shaft-supporting bracket ||3. The gear housing enclosing plate |6| may be removably secured to the gear housing |53 by means oi suitable lag screws or bolts |52, giving free access to the train of gears therein. Thus the driving mechanism for rotor shaft ||6 and runner shaft |33 is completely enclosed, and grease or lubricating oil in the space |43 within the hollow shaft ||6 and the space |66 within the gear box casing |58 is kept in constant agitation by the moving parts to lubricate the gears and shaft-supporting bearings therein.

To illustrate the adaptability of this machine to various operating conditions, there is more particularly illustrated in Fig. 5 a throwing rotor having eight discharge passages |06 and a control runner having seven discharge passages |36. Assuming, for example, that the throwing rotor |00, with eight discharge passageways, has a dif ameter which will give the abrasive fired therefrom the desired blasting velocity when rotated at 2100 R. P. M., it will be appreciated that if the control runner, provided with seven equally spaced discharge passages |36, is rotated at 2400 R. P. M., each discharge passage |36 in the runner will move into discharging alignment with one of the discharge passages |06 in the rotor at a predetermined clockdial position so as to effect the desired directional discharge of the fired abrasive. It will be further noted, by referring to Fig. 5, that, except during the desired discharging arc, the runner passages |36 will be out of alignment with the rotor passages |06 so that no abrasive will be discharged through the discharge passages |06, discharge taking place only when the successive passages |36 move into partial or full augment with successive passages |06.

The desired differential rotative speed between the control runner |30 and the throwing rotor with a discharge passage ratio of eight to seven, as shown in Fig. 5, may be attained by providing the transfer gear |66 and drive gear |66 with a lesser number of teeth than has transfer gear |64 and drive gear |65, as in the ratio of eight to seven in the construction illustrated, so

` that the drive pulley |23 will drive rotor shaft I |6 at 2100 R. P. M. and will drive runner shaft |36 at 2400 R. P. M. In all cases the required speed ratio between the runner shaft and the rotor shaft to obtain discharging alignment o! the passages therein at the desired clock-dial position, will of course be determined and computed on the basis of the number of equally spaced discharge passages in the rotor as compared to the number of equally spaced discharge passages in the runner. Any desired passage ratio and corresponding speed ratio may be selected, as will be fully evident to those skilled in the art.

The abrasive supplied to the runner |30 by the feed pipe |50 will be distributed during rotation of the runner |30 into the discharge passages |36 so as to maintain approximately the same amount of abrasive in each passage, but

-obviously an excessive quantity of abrasive, which would choke the interior of the runner, is not desirable. It will be appreciated that almost any desired quantity of abrasive, from 100 to 1000 lbs. of abrasive per minute and over, can be fed through the machine by merely enlarging the discharge passageways |36 ofV the runner |30 and enlarging the discharge passages |06 in the rotor |00. The abrasive pockets |09 do not interfere with the proper rotative movement of the runner |30 or rotor |00, and since the speed differential between the rotor |00 and runner |30 is so small, no serious frictional wear results. The abrasive is retained within the pockets |00 by centrifugal force but the pockets |61 on the exterior face of th'e runner segments |32 are normally free of abrasive during operation because of the action of centrifugal force. Pockets |61 in each runner segment |32 are defined by the raised end walls |68 and |66 thereof. Since the peripheral length of the riser walls ||0 and of the rotor segments |02 and the riser walls |68 and |69 of the runner segments |32 is relatively short, there is no serious frictional wear or grinding between these parts, and any abrasive lodging between these parts is a1- most immediately moved into the abrasivereceiving cavity |00 or into the discharge passages |06 or |36. To facilitate entry of the abrasive into the receiving cavity |38 of the runner |30, the hub portion |4| thereof may be provided with tapered deilecting surfaces I0 which readily deflect abrasive discharging from the feed spout |50 into the receiving space |38 of the runner |30.

A further modified form of centrifugal abrasive throwing machine is illustrated in Figs. 6,

7 and 8. In this machine the throwingrotor 200 is provided with throwing blades b of substantial length, and the control runner 210 is of reduced diameter so that the abrasive disrelative moving parts thereof.

T-he throwing rotor 200, as shown in Figs. 6, 'I and 8, may comprise a side wall member 20| and a side wall member 202 spaced therefrom and extending generally parallel from side wall member 20|, whichside wall members may be connected by suitable spacers 203 having their reduced ends 204 welded, sweated or otherwise secured to th'e side wall members. Equally spaced radially extending blades b are removably mounted between the spaced side wall members 20| and 202, each blade comprising a bottom wall portion 2|| and side flange portions 2|2 which seat within suitable paired grooves 206 provided on the inside faces of the side wall members 20| and 202. 'Ihe blades b may be removably secured in operative position by means of a suittially in alignment with the inner ends of theblades b. A tubular sleeve member 2|8 extends into the aligned circular openings in the front and rear side wall members 202 and 20| respectively and is provided with an outturned collar portion 2|0 which may be secured as by screws 220 'to the front side wall member 202 so as to rotate with the blades b. The tube 2|8, as sh'own more particularly in Fig. 7. is provided with a discharge opening 220 positioned adjacent the advancing face of each blade b, the openings 228 defining sleeve segments 2 I0' therebetween. Each abrasive discharge opening 226 is denned by the advancing face 223 of one segment 2|8' normally positioned substantially in alignment with or slightly in advance of the advancing face of the bottom portion 2|| of its associated blade b. The following face 224 of each segment 2| 0 de-I fining the other wall of the discharge opening 228 is positioned substantially in augment with the top edge of the flanges 2|2 of its associated blade b. The inner end of each blade b closely abuts against the tubular sleeve 2|8 so that the abrasive moving out through th'e discharge openings 228 as they successively advance is positively directed within the channel confines of its associated blade b. The inside face of the tubular sleeve 2|0 is provided with a plurality of abrasive-receiving pockets 226v each positioned between adjacent discharge openings 228. Each cavity 226, adapted to contain abrasive therein,'is defined between end riser walls 226 and 221. Y

'Ihrowing rotor 200 is rotatably mounted on a hollow drive shaft 23| by means of a hub 23o into which the end of the shaft 23| extends, the shaft 23| and the hub 239 being flxedly secured together by means of a suitable spline 232. Bolts 233 extending through the flange portion of the hub 230 are screwed into threaded apertures provided in the side wall member 28| of the rotor 200 to iixedly secure the rotor 298 to the shaft 23|. To protect the ilange portion of the hub 230 from wear resulting from rebounding abrasive, a suitable rubber gasket 234 may be secured to the peripheral edge thereof.

The shaft 23| may be rotatably supported by two spaced paired bearings each comprising a raceway collar 235 xed to the shaft 23| and a raceway collar 238 supported by the enclosing wall of a suitable bearing housing 231 which is supported by frame members 245. Ball bearings 238 rolling in the raceways provided in collars 235 and 238 permit substantially frictionless rotation of the shaft 23|.

The control runner 210 comprises a tubular member, as shown in Figs. 6 and 7, positioned within the control opening in the throwing rotor 200. The control runner 210 comprises a side wall plate 21| secured to the end of runner shaft 290 by means of a bolt 29|. A tubular wall 212 formed integral with the side wall plate 21| is provided with nine equally spaced discharge openings 213 therein. The tubular wall portion 212 has a tapered end wall portion 214 which may be of generally cone-shaped contour defining a contracted abrasive inlet opening 215. Abrasive is supplied to the interior of the control runner 210 by means of feed spout 218 which g may be provided with an outwardly flared flange portion 211, which serves as a guard protecting the rotating control runner 210.

Abrasive supplied by feed spout 216 to the interior of the control runner 210, is retained by centrifugal force on the interior surface 218 and in the abrasive discharge passages 213 thereof. The discharge passages 213 of the control runner are defined by equally spaced blades or segments, forming the tubular wall 212, each blade or segment having an advancing face 213' and a following face 213". The abrasive is free to collect in the cavities 225 provided in the segments 2|8 of the rotor sleeve, the abrasive being confined in these cavities by the end riser walls 228 and 221.

` As illustrated in Fig. 7, the throwing rotor is provided with eight equally spaced throwing blades b and eight corresponding discharge passageways 228 in the rotating sleeve 2|8 thereof, while the tubular wall 212 of the control runner is provided with nine equally spaced discharge passageways 213, giving a discharge passage ratio of eight to nine. It will now be appreciated that, if the throwing rotor 200 has a diameter which will give the abrasive discharged from the outer ends of the blades b a blasting velocity when rotated at 2250 R. P. M., then if the control runner 210 is rotated at 2000 R. P. M., the discharge passages 213 of the control runner will move into alignment with the discharge passages 228 of the rotor sleeve 2 I 8, at a predetermined clockdial arc during rotation, thus effecting controlled discharge of the abrasive from the machine. Since the diameter of the control runner 210 is small, the outer periphery of the tubular wall portion 212 rotates at relatively low peripheral speed, and since the speed differential between the adjacent tubular portion 212 of the control runner and the adjacent tubular portion of the rotor sleeve 2|8 is only 250 R. P. M., there is no serious wear between these parts. The cavities 225 in the sleeve segments 2|8' provide a seal for the abrasive contained within discharge passages 213 of the control runner so that no abrasive can escape therefrom except when the rotor and runner passages move into alignment or partial alignment, which alignment occurs at the desired clockdial discharging arc only. Any abrasive which may lodge on the tip-ends of riser walls 228 and 221 is driven back into the cavities 225 or permitted to escape through the discharge passages 228 or into the discharge passages 213. Actual test has demonstrated that there is no serious wear between the rotating sleeve 2I8 of the rotor 200 and the tubular wall 212 of the control runner 210.

Adjustments can be made so that the abrasive discharged from the throwing rotor 20|! will be discharged in any desired clockdial direction. This is effected by proper rotative adjustment of the discharge passages 213 in the tubular portion 212 of runner 210 with respect to the discharge passages 228 in the rotor sleeve 2|8. This desired adjustment can be advantageously effected by providing an internal ring gear 293 which is provided with the desired number of teeth around the interioredge thereof, ring gear 293 being fixed as by screws 293' to a plate 282 which has a square axial hole therein into which the square end 290' of runner shaft 290 extends. The rear side wall member 21| of the runner 210 is likewise provided with a circular gear 294 fixed thereto, as by screws 294' which has teeth on the outer periphery thereof which mesh with the teeth in ring gear 293. By removing bolt 29| which extends through the rear side wall member 21| of the runner 210 and screws into the end of shaft 290, the control runner 210 can be rotated the desired amount and the gear teeth in circular gear 294 pushed into mesh with the gear teeth in ring gear 293. It will be appreciated that ring gear 293 and meshing gear 294 have no relative rotative movement during operation of the machine but they both rotate together with the control runner 210. By providing, for example, sevent-y-two teeth in the ring gear 293 and plate gear 294, the passages 218 in the runner may be shifted as little as 5 up to 360, producing a corresponding shift in the direction of discharge of the abrasive from the throwing rotor. Very closely determined directional control adjustments of the machine can thus be attained.

The runner end of runner shaft 290 is rotatably supported within the tubular rotor shaft 23| by means of a suitable bearing comprising bearing runner 296 fixed to shaft 290 and bearing runner 298 iixed to the interior of tubular shaft 23| between which bearings 291 are adapted to roll. Lubricating oil contained within the interior of the tubular shaft 23| is prevented from escaping into the control runner 21|)A by a suitable oil seal comprising oil gasket 299 which rubs in contact with the runner end of shaft 290 and which is contained within a gasket-receiving collar 300 of Y channel-shaped cross-section fixed to the inraceways within which roller bearings 251 are adapted to roll.

The driving mechanism driving the rotor shaft 25| and the runner shaft 250 in timed relation may be housed within a suitable drive casing 231 supported upon frame members 255. A power transmission shaft 25| is journaled in suitable bearings supported by inwardly extending flanges 250 and 265 formed as a part of the gear housing 231. The inner end 25|' of shaft 25| may be of reduced diameter. to retain bearing nmner 255 xedly secured thereto. Bearing runner 255 is flxedly secured to the casing flange 255 and ball bearings 251 are positioned to roll between normally stationary bearing runner 255 and rotating bearing runner 255. 'I'he other end of shaft 25| is supported in a suitable bearing comprising bearing runner 25| xed to the reduced end 25|" of shaft 25| and bearing runner 255 fixed to inwardly extending casing flange 255. Ball bearings 252 roll between normally stationary bearing runner 255 and rotating bearing runner 25|. The projecting end of shaft 25| carries a drive pulley 250 over which a V-belt drive may be trained, the pulley 250 being secured to the projecting end of shaft 25| as by Spline 252.

The drive casing 251 may be capped by a suitable closure 255 having an outwardly extending iiange 255 which is suitably bolted or otherwise secured ton outwardly extending flange 255 of drive casing 231. The interior space 245 of drive casing 231 is adapted to contain lubricating oil which is kept in constant agitation by the mov- -ing parts of the driving mechanism contained therein, which will be presently described. Ac-

cess to the driving mechanism within the drive casing 251 may be had by removing a closure plate 255 which uncovers an opening 255' in the end wall of the drive casing 251. giving free access to the interior thereof. Closure plate 255 may be bolted to the inturned rim 255" surrounding the opening 255'. The drive end of shaft 25| projects through a shaft opening in cover plate 265, a suitable shaft seal Abeing provided, which is fixed to the flange portion 255 surrounding the shaft opening in cover plate 255. The bearing seal may comprise 4a stationary gasket 258 which rubs in contact with the shaft 25|, the gasket being retained in fixed position by means of a gasket collar 251 of channel-shaped cross-section xed to the flange portion 255.0! cover plate 255.

The power transmission shaft 25| is operatively connected to rotor shaft 25| by means of a Morse drive 305 which is trained over drive sprocket 501 fixed to transmission shaft 25| as by spline 508 and trained over sprocket 555 fixed to rotor shaft 25|. Runner shaft. 250 is also driven from transmission shaft 25| by means of a vMorse drive trained over sprocket 5|2 fixed to transmission shaft as by spline 3|5 and trained over sprocket 50| fixed to the end or runner shaft 250 as by spline 502. A suitable washer 505 and bolt 555 screwed into the end of shaft 290 secures sprocket 50| thereon.

It will now be appreciated that when power is applied to rotate pulley wheel 255, z :f1 n shaft 25| is rotated and "Morse" drive 30 operstes to rotate shaft 25| so as to rotate the throwing rotor 200 at the desired abrasive blasting velocity. Runner shaft 290 is rotated in timed relation with rotor shaft 25| by Morse" drive 3| the proper drive ratio between rotor shaft 23| and runner shaft 290 being attained by providing sprockets 551 and 5l2 with the required number of teeth. By way of example, if the throwing rotor 255 havingeight throwing blades issettorotateat2250R.P lL,thecontrolrun ner 215 having nine abrasive discharge passageways 213 would be set to rotate at 2000 R. P. M., which relatively timed rotation is effected by making sprockets 551 and 5| 2 in the drive ratio of nine to eight.

It will be appreciated that the throwing rotor' 255 may be made in any desired diameter and may be rotated at any dired-speed, the control runner 215 being rotated at a corresponding speed ratio determined by the relative number of discharge passageways or blades in the rotor 255 with respect `to the discharge passageways in the runner 210. Thus the rotor 250 and runner 215 are rotated at speeds which are in inverse ratio to the number of abrasive discharge ports therein, so that each runner port will line up with a rotor port at the same clock-dial position during rotation. The runner ports and the rotor ports can be so adjusted that alignment thereof occurs at any desired clock-dial position during rotationI by merely adjusting the setting of the control runner 210 and the ports 215 therein with respect to the ports inthe rotor sleeve 2I5.

It will rvbe appreciated that in the several illustrated embodiments of this invention the throwing rotor may be provided with any desired num ber of throwing blades or discharge passages, and a high degree of directional control can be com tnuously maintained by providing a control runner having either a greater or lesser number of discharge es. preferably providing the controlrunnerwitheitheronemoxeoronelessdischarge passage than those provided in the throwing rotor, if abrasive iii-ng from a single selected clock-dial position is desired. The abrasivemaybetiredfromthethrowingrotorlnany desired clock-dial direction by a proper mathematical adiustment of the control runner with respect to the throwing rotor.

, for example. that the throwing rotor is provided with eight equally spaced discharge eways or blades and the control runner is providedwithnineequallyspaced dischargepasssgorbladeassshown inPlg. 'Landthat itis desired to shift the direction of discharge from a normally downward or six oclock position to a normally sideways or three oclock position, with the rotor and runner rotated clockwise. This control adjustment can be effected byy rotating the control runner 210, shown in Fig. '1, soasto bring oneof the nmner dischargeports 215 into alignment with one of the rotor sleeve ports 225. at approximately the nine oclock position. This would require rotation of the control runner 210 a distance of approximately 10 countex-clockwise from its position shown in Fig. 7 wheretherunnerand rotorpartsareshownin alignment at the 12 oclock position. This assumes, of course, that the rotor blades b are of such length that when the abrasive is moved onto the inner ends thereof at approximately thc nine oclock position, it will be discharged at approximately the three oclock position. The arc through which the abrasive is carried by the v rotor blades or segments after being received on the inner ends thereof and before being discharged therefrom, obviously depends upon various conditions such as the radial length of the rotor blades and the smoothness of the throwing surfaces thereof. 'I'he number of degrees that the control nmner should be rotated to eii'ect the desired directional discharge cangenerally be computed to a mathematical certainty, but the proper adJustment can most readily' be determined in actual practice by trial and thereafter from resulting experience with a particular machine.

It may at times be desired to clean. castings, forgings, bars and sheets which are positioned on opposite sides of the throwing rotor. My improved centrifugal abrasive throwing machine may be constructed and designed to accomplish this result by providing the machine with a control runner having equally spaced abrasive discharge blades or passages either two more or two less in number than the abrasive discharge passages or ports in the throwing rotor. The control runner and throwing rotor are then rotated in timed relation so that two opposite discharge passages or ports in the control runner will align with two opposite discharge passages or ports in the throwing rotor at two opposed clockdial positions during rotation thereof.

There is shown in Fig. 10 a machine constructed in accordance with the machine shown in Figs. 6, '1 and 8, except that the tubular wall 212 of the control runner 210 is provided with ten abrasive discharge passages or ports 213, the tubular sleeve 218 of the throwing rotor being `provided with eight discharge passages or ports 228. Assuming that simultaneous upward ring and downward firing of the abrasive are desired one of the discharge passages 213 of the control runner 210 is brought into alignment with one of the discharge passages 228 of the rotor sleeve 2l8 at approximately the twelve oclock position so as to achieve a directed downblast of the abrasive thrown by blade b. When this alignment is effected, as shown in Fig. l0, another of the discharge passages 213 of the control runner will align with another ofthe discharge passages 228 of the rotor sleeve at approximately the six oclock position so as to achieve a directed upblast of the abrasive thrown by the blades b. With the control runner 210 equipped with ten equallyspaced discharge passages 213 and the rotor sleeve 218 equipped with eight equally spaced discharge passages 228, controlled firing of two oppositely directed abrasive streams can be eiected by rotating the rotor at 2500 R.. P. M. and the control runner at 2000 R. P. M., effected by providing the required tooth ratio on the drive sprockets 301 and 3 l 2, shown in Fig. 6.

As a further illustration of the possibilities of this machine to produce a simultaneous oppositely directed blasts of abrasive therefrom, there is shown in Fig. 11 a centrifugal blasting machine constructed in accordance with the machine shown in Figs. 1 to 3 inclusive, except that the control runner 40 is provided with eighteen equally spaced discharge passages or ports 45 and the throwing rotor i is provided with sixteen equally spaced discharge passages or ports I5. By rotating the throwing rotor I0 at 2250 R. P. M. and the control runner 40 at 2000 R.. P. M., controlled firing in two opposite directions from the same throwing rotor l0 is obtained.

The direction of discharge of the streams is, of course, determined by the clockdial position at which the discharge passages or ports in the control runner and the discharge passages or ports in the throwing rotor move into alignment, so as to deposit abrasive on the advancing passages or blades of the throwing rotor. Once the abrasive has been deposited in the discharge passages or on the throwing blades of the throwing rotor, the abrasive will be centrifugally thrown by the advancing faces thereof in a direction determined by the lengthl of the discharge passages or blades, the smoothness of the discharge passages, and other factors which are constants of the particular machine.

Thus it will be appreciated that accurate and controlled firing in one direction only or in two or more predetermined directions from the same machine can be attained by providing the control runner and throwing rotor with the proper number of discharge passages or ports and rotating the runner and rotor at speeds which are in inverse ratio to the number of discharge passages or ports therein. Upblast or downblast, or both upblast and downblast, a three oclock sideblast or a nine oclock sideblast, or both a three oclock and a nine oclock sideblast, may be attained with a machine constructed as above described.

The throwing rotor may be ofany desired diameter, preferably ranging from nine to thirty inches, and the throwing blades or passages on the throwing rotor may be of any desired radial length and, if desired, may be of such length as to extend close to the axis of rotation providing only a sufllcient central opening in the rotor to make room for the control runner positioned therein. When the blades of the throwing rotor are of substantial length, it is obvious that wear on the control runner and the rotor sleeve may be correspondingly reduced with greater wear concentrated on the throwing blades of the rotor, which may be made removable and replaceable. If the throwing blades or discharge passages of the throwing rotor are of relatively short radial length with a corresponding increase in diametric size of the control runner, the control runner, and particularly the blades or discharge passages thereof which will then receive some wear, maybe made removable and replaceable, as is obvious to those skilled in the art.

The abrasive receives its final abrading velocity from the advancing facesof the rotor blades or segments and the "advancing faces or surfaces thereof are preferably made removable so that these parts can be replaced when worn. The

parts of the machine which receive tensile strains and shocks may be made of a high grade of steel, and the parts subjected to wear maybe made of a suitable wear-resisting metal.

The directional control adjustment of the machine may be made by a slight shift adjustment of the rotor onits supporting shaft or the runner on its supporting shaft, or the adjustment can?.` be effected by a slight rotative shift of one of the" driving sprockets or gears connected either to the rotor shaft, the runner shaft or to the power transmission shaft.

Actual tests have demonstrated that a high degree of directional control may be attained by a machine constructed as herein disclosed. The abrasive is given a uniformly accelerated velocity by the runner which finally discharges abrasive therefrom into the rotor passages or upon the inner ends of the rotor blades as they move into alignment with the respective runner passages or blades. The speed of the abrasive when discharged from the runner passages or blades into or on the rotor passagesor blades is a speed which closely approaches the speed of the rotor passages or blades, sothat the abrasive is received upon the advancing face of the rotor blades or segments at approximately the speed of travel thereof. If the runner is made with one less blade or passage than the number provided in the rotor, the peripheral velocit'y of the runner passages or blades is actually greater than the speed of the inner ends of the rotor blades or passages, so that the abrasive is delivered onto the runner blades or-passages substantially without shock as a result of the transfer. Actual test has demonstrated that the quantity of abrasive break-up and the amount of blade wear in this machine is substantially less than that occurring in prior art centrifugal blasting machines including the well-known control cage and impeller type of machine. The blades or throwing segments in the rotor and runner thus have long life in use and little or no abrasive break-up resuits during movement of the abrasive through the machine. a

A further advantage of the machine herein disclosed resides in the great accuracy with which the direction of discharge may be controlled in any desired clockdial position, whether the target, comprising the steel sheet, casting or forging, is positioned below or above the machine, to either side of the machine, or at any other relative position. Directional ring can be controlled within or less.

Another great advantage of the machine herein disclosed is the great uniformity in the blast pattern produced. The abrasive is distributed uniformly over the entire width of the rotor blades or segment, producing more uniform wear on each of these blades or segments, with a resulting full width impingement pattern on the target. The length of the impingement pattern on the target can be easily fixed and determined by varying the peripheral length of the discharge passages in the rotor or the peripheral length of the discharge passages in the runner or by varying the length of both, so that the discharge passages in the runner and rotor are in partial or complete alignment over a longer or shorter. arc during rotation. It will be appreciated that where the discharge passages in the rotor or runner or both are of greater peripheral length, these passages will remain in partial or full alignment over a greater arc during synchronized rotation of the runner or rotor. Thus by varying the peripheral length of the passages in the runner or rotor or both, an impingement pattern on the target of almost any desired length can be obtained within the capacities of the machine.

It will be further appreciated that when an impingement pattern of substantial length is desired, it may be effected by enlarging the peripheral length of the passages in the runner or rotor or both, and more abrasive can be red by the machine so that the same intensity of impingement can be attained over the entire length and Width of a longer impingement pattern as over a shorter one, a result which cannot be attained by centrifugal blasting machines now known or in use. Where an impingement pattern of approximately twenty inches in length is desired from a rotor having a diameter of approximately twenty inches, the machine will directionally discharge Without overloading as much as 300 lbs. of abrasive per minute, or more. A longer impingement pattern with the same impingement intensity is obtained by increasing the peripheral length of the discharge passages in the rotor or runner'or both, the machine then having a correspondingly increased abrasive throwing capacity, since obviously more abrasive can be discharged through a larger discharge passage than a smaller one. The width of the impingement pattern can also be determined as desired by increasing the width of the discharge passages or blades in the rotor and runner with the assurance that the full blade width of both rotor and runner will be utilized in throwing abrasive.

It is understood that where the term abrasive is herein used, it is intended to refer to steel shot or grit, quartz sand and other granular materials commonly used in the blast cleaning of castings, forgings, bars, sheets and like metallic materials, to remove encrusted molding sand, ir-

regular projections, and scale from the surface zol thereof.

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. A centrifugal abrasive blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced abrasive discharge passages extending inwardly short of the axis of rotation thereof defining a central space, a rotatably mounted control runner positioned within said` central space and having its axis of rotation in alignment with the axis oi rotation of said rotor, said control runner having a plurality of equally spaced abrasive discharge passages differing in number from the number of discharge passages in said rotor, means for supplying abrasive to the discharge passages of said runner, and driving means operable to rotate said rotor and runner at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectivehr so as to move the successive passages in said runner into discharging alignment with the successive passages in said rotor at a predetermined ciockdial position during rotation.

2. A centrifugal abrasive blasting machine operable to throw two oppositely directed concentrated streams of abrasive each discharged over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced abrasive discharge passages which extend inwardly short of the axis of rotation thereof defininga central space, a rotatably mounted control runner positioned 'within said central space with the axis of rotation of said runner in substantial alignment with the axis of rotation of said rotor, said control runner having a pluralityof equally spaced abrasive discharge passages differing in number by two from the number of discharge passages in the throwing rotor, meansfor supplying abrasive to the discharge passages of said runner, and means for rotating said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively.

3. A centrifugal abrasive blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced abrasive discharge passages, a rotatably mounted control runner having a plurality of equally spaced abrasive discharge passages therein difiering in number from the discharge passages of the throwing rotor, said runner having its axis of rotation concentric with the axis of rotation of said rotor with the outer ends of the passages in the runner positioned means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move the discharge ends of the successive passages in said runner into discharging alignment with the inner ends of the successive passages in said rotor at a predetermined clockdial position during rotation.

4. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotor comprising a rotatably mounted sidewall member having a plurality of throwing elements supported by saTid side wall member defining equally spaced abrasive discharge passages therebetween, a control runner comprising a rotatably mounted side wall member having a plurality of throwing elements mounted thereon defining equally CFI sages. means for supplying abrasiveto the discharge passages in said runner, and driving mechanism operably connected to said shafts whereby said rotor and runner can be rotated 1n timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move the successive passages in said runner into spaced abrasive discharge passages therebetween with the discharge passages in said runner differing in number from the discharge passages in said rotor, said runner having its axis of rotation substantially concentric with the axis of rotation of said rotor with the outer ends of the passages in the runner positioned adjacent the inner ends of the passages in said rotor, means for supplying abrasive to the discharge passages in said runner, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move the discharge passages in said runner into discharging align-` ment with the successive passages in said rotor at a predetermined clockdial position during rotation.

5. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotor comprising a rotatably mounted side wall member and an overhanging rim supported by said side wall member having equally spaced discharge ports therein, a control runner fitting within said rim comprising a rotatably mounted side wall member whose axis of rotation is concentric with the axis of rotation of said rotor, and a laterally extending rim supported by the side wall member of said runner and positioned adjacent the inner periphery of said rotor rim, said runner rim having equally spaced discharge passages therein diering in number from the discharge passages in said rotor rim, means for supplying abrasive to the discharge passages of said runner, and means for rotating said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively.

6. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted shaft, a rotor having equally spaced abrasive discharge passages supported on said shaft, a second shaft having its axis of rotation substantially concentric with the axis of .rotation of said first shaft, a control runner mounted on said second shaft having equally spaced abrasive discharge passages differing in number from the n number of discharge passages in said rotor, said runner being arranged so that the outer ends of the runner discharge passages are positioned adjacent the inner ends ofy said rotor discharge pasdischarging alignment 'with the successive passages in said rotor ata predetermined clockdial position during rotation.

7. A centrifugal abrasive blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotor having equally'spaoed abrasive discharge passages extending inwardly short of the -axis of rotation thereof to denne a central space, aV rotatably mounted shaft fixed to said rotor, a control runner positioned within said central space having equally spaced abrasive discharge passages therein differing in number from the number of discharge passages in said rotor, a second rotatably mounted shaft xed to said runner having its axis of rotation concentric with the axis of rotation of said rotor shaft, adrive pulley adapted to be connected to a power source, and mechanism operably connecting said pulley to said shafts whereby said shafts may be rotated at speeds which arein inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive passages in said runner into discharging alignment with successive passages in said rotor at a predetermined fering in number from the number of discharge passages in said rotor, a second rotatably mounted drive shaft having one end thereof fixed to said runner, said runner shaft having its axis of rotation substantially concentric with the axis of rotation of said rotor shaft, a power transmission shaft, means operably connecting the power transmission shaft to said runner shaft anr'l, rotor shaft, and a drive pulley operably connected to one of said shafts, said means connecting said transmission shaft to said rotor and runner shafts being operative to establish a drive ratio between said runner shaft and rotor shaft which is in inverse proportion .to the number of passages in said rotor and runner respectively.

9. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotor having equally spaced abrasive discharge passages therein extending inwardly short of the axis of rotation thereof to define a central space, a rotatably mounted tubular drive shaft having one end thereof fixed to said rotor, a control runner positioned within said central space having equally spaced abrasive discharge passages f therein differing in number `from the number of discharge passages in said rotor, a second rotatably mounted drive shaft positioned within said tubular drive shaft having one end thereof fixed to said runner. said runner shaft having its axis of rotation substantially concentric with the axis of rotation of said rotor shaft. means for supplying abrasive to said runner passages, and driving mechanism operably connected to said shafts whereby said rotor and runner may be rotated in timedrelation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move the successive passages in said runner into discharging alignment with the successive passages in said rotor at a predetermined clockdial position during rotation. y

10. A centrifugal abrasive blasting machine operable to throw two oppositely directed concentrated streams of abrasive each discharging over a predetermined limited arc including, a rotatably mounted rotor having an even number of equally spaced abrasive discharge passages therein which extend inwardly short of the axis of rotation thereof to define a central space, a rotatably mounted control runner positioned within said central space and having its axis of rotation substantially in alignment with the axis of rotation of said rotor, said control runner having an even number of equally spaced abrasive discharge, passages therein two more in number than the number of discharge passages in the throwing rotor, means for supplying abrasive to said runner passages, and means for rotating said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so `as to move the successive passages in said runner into discharging alignment with the successive passages in said rotor at two predetermined opposite clockdial positions during rotation, said rotor and runner having cooperating elements rotating therewith blocking escape of abrasive from said runner passages into said rotor passages except at said predetermined clockdial positions.

11. A centrifugal abrasive blasting machine operable to throw two oppositely directed concentrated streams of abrasive each discharging over a predetermined limited arc including, a rotatably mounted rotor having an even number of equally spaced abrasive discharge passages therein which extend inwardly short of the axis of rotation thereof to define a central space, a rotatably mounted control runner positioned within said central space and having its axis of rotation substantially in alignment with the axis of rotation of said rotor, said control runner having an even number of equally spaced discharge passages therein two less in number than the number of discharge passages in the throwing rotor,`

means for supplying abrasive to said runner passages, Aand means for rotating said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move the successive passages in said runner into discharging alignment with the successive passages in said rotor at two predetermined opposite clockdial positions during rotation, said rotor and runner having cooperating elements rotating therewith blocking escape of abrasive from said runner passages into said rotor passages except at said predetermined clockdial positions.

12. A centrifugal abrasive blasting machine operable to throw a concentrated stream of=abra sive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced circumferentially extending segments defining abrasivedischarge passages therebetween, a rotatably mounted sam--- axis of rotation in substantial alignment with the axis of rotatlonof said rotor, said runner having a plurality of equally spaced circumferentially extending segments defining abrasive discharge passages therebetween diil'ering in number from the number of discharge passages in said rotor, said runner being arranged so that the outer ends of the runner discharge passages are positioned adjacent the inner ends of said rotor discharge passages, means for supplying abrasive to said runner passages, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in the said rotor and runner respectively so as to move said passages in said runner into discharging alignment with the successive passages in said rotor at a predetermined clockdial position during rotation, said rotor and runner segments cooperating to block the escape of abrasive from said runner passages into said rotor passages except at saidpredetermined clockdial position.

l3. A centrifugal abrasive blasting machine voperable to throw a concentrated stream of abrasive over a predetermined limited. arc including,

a rotatably mounted rotor having a plurality of equally spaced circumferentially extending segments defining abrasive discharge passages therebetween, a rotatably mounted runner having its axis of rotation in substantial alignment with the axis of rotation of said rotor, said runner having a plurality of equally spaced circumferentially extending segments defining abrasive discharge passages therebetween differing in number from the number vof discharge passages in said rotor, said runner being arranged so that the outer ends of the runner discharge passages are positioned adjacent the inner ends of the rotor discharge passages, means for supplying abrasive to said runner passages, said rotor segments having an abrasive receiving cavity in the inner facing surface thereof positioned between each pair of adjacent abrasive discharge passages deiined by said segments, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive runner passages into discharging alignment with successive rotor passages at a predetermined clockdial position during rotation.

14. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced circumferentially extending segments dening abrasive discharge passages therebetween, said segments each having a generally arcuate shaped inner end defining therebetween a central space of generally circular form, a rotatably mounted runner positioned within said central'space and having its axis of rotation substantially concentric with the axis of rotation of said rotor, said runner having a plurality of equally spaced circumferentially extending segments defining abrasive discharge passages therebetween differing in number from the number of discharge passages in said rotor, means for supplying abrasive to said runner passages, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive runner passages into discharging alignment with successive rotor passages at a predetermined clockdial position during rotation.

15.. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced radially arranged throwing blades extending inwardly short of the axis of rotation of said rotor to dene a central space, a tubular sleeve extending into said space fixed to rotate with said blades, said sleeve having an abrasive passage in the tubular side wall thereof adjacent the inner end of each of said blades, a rotatably mounted control runner fitting within said sleeve f and having its axis of rotation substantially ccncentric with the axis of rotation of said sleeve, said runner comprising a tubular member having equally spaced discharge passages in the tubular side wall thereof differing in number from the number of discharge passages in said rotor sleeve. means for supplying abrasive to said runner passages, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive runner passages into discharging alignment with successive rotor passages at a predetermined clockdial position during rotation.

16. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor comprising spaced side wall members, a plurality of equally spaced segments supported by said side wall members extending inwardly short of the axis of rotation of said rotor defining a central space, said rotor segments deiining abrasive discharge passages therebetween, a control runner fitting within the central space dened by said rotor segments and having its axis of rotation substantially concentric with the axis of rotation of said rotor, said runner comprising spaced side wall members, equally spaced passage-defining segments fixed to said runner side walls extending inwardly short of the axis of rotation of said runner to define a central space, said runner passage. diiering in number from the number of passages in said rotor, means for supplying abrasive to the central space and passages of said runner, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive runner passages into discharging alignment with successive rotor passages at a predetermined clockdial position during rotation.

17. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced radially extending throwing blades extending inwardly short of the axis of rotation of said rotor to dene a central space, a tubular sleeve extending into said space xed to rotate with said blades, said sleeve having an abrasive passage in the tubular side wall thereof adjacent the inner end of each of said blades, a rotatably mounted control runner snugly tting within said sleeve and having its axis of rotation substantially concentric with the axis of rotation of said sleeve, said runner comprising a tubular member having equally spaced discharge passages in the tubular side wall thereof diiering in number from the number of discharge passages in said rotor sleeve, said rotor sleeve having an abrasive-receiving cavity in the inner facing surface thereof positioned between each pair of adjacent abrasive discharge passages therein, means for supplying abrasive to said runner passages, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively 'so as to move successive runner passages into discharging alignment with successive rotor passages at a predetermined clockdial position during rotation.

18. A centrifugal abrasive blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having equally spaced abrasive discharge passages extending inwardly short of the axis of rotation thereof defining a central space, a rotatably mounted control runner positioned within said central space and having its axis of rotation substantially concentric with the axis of rotation of said rotor, said runner having a plurality of equally spaced abrasive discharge passages diiering in number from the number of discharge passages in said rotor, means for supplying abrasive to the discharge passages of said runner, and driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive runner passages into discharging alignment with successive rotor passages at a prede-,K termined clockdial position during rotation, the length of path swept by the fired abrasive being determined by the peripheral length of the discharge passages in said rotor or runner or both.

19. A centrifugal blasting machine operable to throw a concentrated stream of abrasive over a predetermined limited arc including, a rotatably mounted rotor having a plurality of equally spaced abrasive discharge passages extending inwardly short of the axis of rotation thereof dening a central space, a rotatably mounted control runner positioned Within said central space and having its axis of rotation substantially concentric with the axis of rotation of said rotor, said runner having a plurality of equally spaced abrasive discharge passages differing in number from the number of said rotor discharge passages. means for supplying abrasive to said runner discharge passages, driving means operable to rotate said rotor and runner in timed relation and at speeds which are in inverse ratio to the number of discharge passages in said rotor and runner respectively so as to move successive runner passages into discharging alignment with said rotor passages at a predetermined clockdial position during rotation, and means for adjusting the clockdial aligned position of said rotor and runner passages to determine the direction of discharge of the abrasive iired from said rotor.

LLOYD L. HOBSON.

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