US2077635A - Abrasive throwing wheel - Google Patents

Description

April 20, 1937.

v. E. Ml NlCH ABRASIVE THROW'ING WHEEL Filed June 21, 1935 2 Sheets-Sheet l INVENTOR Vemzflflzhztlz Y ATTORNEY P 20, 1937- v. E. MINICH 2,077,635

I ABRASIVE THROWING WHEEL Filed June 21, 1955' 2 Sheets-Sheet 2 W////// y W ATTORNEYS I UNITED STATES PATENT OFFICE ABRASIVE 'rrmowmo. WHEEL Verne E. Minich, Mjshawaka, Ind., assignor to The American Foundry Equipment Company, Mishawaka, Ind., a corporation of Delaware Application June 21, 1935, Serial No. 27,647

' 12 Claims.

This invention relates to an improved abrasive throwing wheel of the centrifugal type designed to forcibly throw granular abrasive particles, such as sand, steel shot, grit and. the like at velocities effective to clean and polish hard metallic objects, such as castings, forgings, bars and sheets.

It is one of the purposes of this invention'to provide an improved wheel for throwing abrasive at blasting velocities which is strong and durable,

light in weight, and which offers minimum resistance to rotation at high speed, thereby effecting a considerable saving in horsepower consumption. In accordance with this invention, the wheel comprises spaced side wall members preferably formed of strong wear resisting steel connected together in fixed spaced relationship by suitable studs or connecting bolts. The wheel is mounted on the end of a drive shaft rotatably mounted in bearings which permit the shaft i to rotate without vibration. Removable channel shaped blades formed of hard wear resisting material are radially arranged between the side wall members and extend from the periphery of the wheel inwardly short of the rotating axis so as 25 to provide a central chamber at the center of the wheel. The blades extend into and are preferably supported within spaced grooves provided in the inside face of the side wall members. Key bolts or screws may be used to removably secure 30 the blades in fixed position.

The abrasive is fed into the path of an impeller fixed to one of the side wall members to rotate with the wheel. The abrasive is thrown by the impeller with considerable velocity out through a 35 discharge outlet provided in the side wall of a tubular control member which surrounds the impeller and thus comes into contact with the inner ends of the blades without destructive shock to the blades or abrasive. The control member re- 40 mains stationary during rotation of the wheel but is preferably adjustably mounted so that the discharge outlet therein can be moved into any clock-dial position to thereby control the direction of flight of the thrown abrasive. An imp ses.

In operating an abrasive throwing wheel of this character in eflicient proximity to the work surface, a considerable quantity of the abrasive will rebound from the work surface and strike the wheel. It is also believed that a certain quantity of abrasive lags behind each rapidly rotating blade as'it leaves the blade and moves inwardly within the periphery of the wheel. Such rebounding or lagging abrasive can do little harm to the side wall members of the wheel as herein constructed. The only other surface that such rebounding or lagging abrasive can strike is the advancing face'of a throwing blade, and would then again be thrown against the work. It will be noted that the stud elements connecting the side wall members in fixed spaced relationship are positioned inwardly of the wheel periphery and directly behind the throwing blades and thus are completely removed and out of the path of rebounding or lagging abrasive.

It will also be noted that in the wheel herein described air is free to circulate around the control member and around the inner ends of the blades, with the result that no vacuum or pressure pockets are built up during rotation of the wheel to influence the normal desired movement of the abrasive moving through the wheel. Freedom from outside influences and other variables is one of the desirable results obtained by the construction herein presented, and more accurate control of the thrown abrasive and a considerable decrease in horsepower consumption is realized. The wheel is furthermore unusually strong and sturdy, will last indefinitely with infrequent blade replacements, and is simple and economical to construct and operate.

In order that this invention may be clearly understood and readily carried into effect, the same will now be more fully described with reference to the accompanying drawings, illustrating by way of example, several embodiments of the invention, and in which:

Fig. 1 is a side view of the wheel as it appears when assembled, certain parts being broken away to more clearly illustrate the construction;

Fig. 2 is an end view of the wheel shown in Fig. 1;

Fig. 3 is a transverse cross sectional View through the wheel taken on line 3-3 of Fig. 1;

Fig. 4 is an enlarged fragmentary cross sectional view taken on line 4-4 of Fig. 1;

Fig. 5 is a perspective view of a removable and replaceable throwing blade;

Fig. 6 is a perspective view of the tubular control member by means of which the abrasive discharge is controlled; and

Fig. 7 is a diagrammatic view illustrating the direction of movement of the abrasive thrown from the wheel when equipped with the control member shown in Fig. 6.

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

The wheel generally comprises a rear side wall disc i and a front side wall disc 2 connected together by a plurality of stud elements 3. The stud elements 3 are provided with reduced end portions 8 which extend into corresponding openings in the disc and with shoulder portions 1 which maintain the discs I and 2 in fixed spaced relationship. The discs I and 2 may be rigidly secured to the reduced ends 8 by plug welding the parts together, as at 9. The wheel is mounted on a rotatable shaft 4 having a hub 5 connected by means of bolts 6 to the disc I. Throwing blades b extend from the periphery of the wheel inwardly short of the rotating axis so as to provide a central chamber 0. The blades are preferably mounted so that the throwing face thereof lies in a radial line, although the blades can be arranged to deviate from the radial, if desired. Each blade is formed from hard wear resisting material comprising a bottom portion I00 and side flange portions I0| providing a channel shaped member adapted to retain the abrasive therein as it moves across the face thereof. The flange portions ll of the blade preferably seat within corresponding grooves [0 provided in the side wall discs I and 2 of the wheel. Removable screws 3| provided with inner tapered portions 32 project through the side wall discs I and 2, and engage the undersurface of the blades b to retain the blades in fixed position within the wheel, and the flanges I III in abutment against the overhanging shoulders I3. The blades may each be provided with a grooved recess I02 into which the tapered end of the screws 3| project.

A tubular control member I 0, which may have an inwardly extending flange l3 at the inner end thereof, extends into the central chamber 0. The control member Ill is mounted independently of the wheel on a suitable support M. A rotating impeller is mounted within the control member and fixed to rotate with the wheel. The impeller comprises a rear side plate l5 and a front side plate It: connected by a plurality of radiating impeller vanes I 'l. The impeller may be connected to rotate with the side wall discs by means of a bolt l8 which screws into a centering plate l9 fixed to the rear side wall disc I by means of the screws 2!. The abrasive flows from a feed pipe 50 into the impeller through the large center opening 22 in the front side plate l6 of the impeller. The abrasive drops radially across the impeller vanes l1 and is then whirled within the tubular control member in until discharged through the opening 0 therein. The abrasive is thrown out through the discharge openings 0 with considerable force across the inner ends of the blades 1) and into the path of rotation thereof. It will be noted that since the impeller rotates with the blades and substantially at the same speed, the abrasive moves gently on to the advancing face of the blade without destructive shock to the abrasive or to the inner end of the blade. The abrasive gains momentum as it moves across the ace of he blade and is thrown from the outer ends of the blade with great force. Under the same operat ing conditions a fixed relationship exists between the clock-dial position of the discharge outlet in the control member and the point of discharge from the wheel. By adjusting the position of the discharge opening 0, the direction of the abrasive thrown by the wheel may be regulated and controlled. The position of the discharge opening 0 is adjusted by rotating the control member H) which brings the discharge opening to the point desired.

The overall length of the discharge opening 0 determines the length of path swept by the thrown abrasive. Where only one opening of considerable peripheral length is provided, however, the abrasive is not evenly distributed over the work surface W. It has been discovered that this can be overcome by providing a series of spaced openings 01, 02, 03, and 04 in the control member, as shown more particularly in Figs. 1, 6, and 7, which openings progressively increase in area in the direction of rotation of the wheel. This desirable result may be theoretically explained as follows. By referring more particularly to Fig. 7, it will be noted that the impeller vanes l1 rotating in a clockwise direction first pass over the opening 01, causing a certain amount of abrasive to be thrown therefrom. In

order that a corresponding quantity of abrasive be ejected from the opening 02, it is necessary that the opening be of greater peripheral length, since the impeller vane has already discharged part of its load of abrasive through the previous opening or openings. By thus varying the area of the openings preferably by gradually increas-- ing the peripheral length of the openings 01, 02, O3, and 04 in the direction of rotation of the impeller, the proper quantity discharge can be had from each opening. It may be assumed, therefore, that the abrasive discharged from the opening 01 will be discharged along the path (11 and accordingly the abrasive discharge from the openings 02, 0a, and 04 will be discharged along the paths as, as, and 114. The proper size of the variegated openings to obtain even distribution of the abrasive against the work surface W can readily be determined by test for the particular type of abrasive to be used.

It is important that all the abrasive discharged through the control opening 0 be confined entirely within the channel shaped blades. By referring more particularly to Fig. 8, it will be noted that the centering plate l9 projects into the central chamber 0 a distance substantially equal to the thickness of the side flange ll of the blades. When the throwing blade b is in operative position, the inner end I03 thereof abuts against the circumferential edge 35 of the centering plate, thereby limiting and centering the inserted position of the throwing blade. The centering plate l2 extends over the inside flange of the throwing blade and prevents the abrasive from working in between the wear blade and the rear side wall disc I. The inner end of the blades is beveled at I05 at approximately a 45 angle presenting a knife or feather edge which cuts or cleaves the abrasive stream so as to prevent spattering of the abrasive within the wheel.

Should the abrasive be inclined to work in between the side edge of the blades and the front side wall member 2, the front side wall disc 2 may be protected by means of a circular gasket 40 which surrounds the tubular control member Ill and is secured to the front wall 2. The gasket 40 is circular in form and tightly abuts against the front side flange Illl of the blades so as to prevent the abrasive from .working in between the side flange of the blades and the side wall disc 2. The gasket may be made of soft rubber or other wear resisting material and may be held in position by means of a metallic ring 43 which is secured to the front wall 2 by means of screws l4. The ring 13 may be provided with an outwardly extending flange 42 which gives additional protection to the front face of the wheel. The gasket 40 fits closely around the outside face of the tubular member Ill, thus eliminating or greatly reduc- 15 ing spillage of the abrasive which might otherwise work out of the machine between the tubular control member 10 and the side wall disc 2.

A wheel having a diameter of approximately inches and a blade length of 7 to 8 inches rotated 20 at about 2200 R. P. M. will throw the abrasive approximately as shown in Fig. '7. The abrasive discharged from the variated openings 01, 02, a,

and 04 will be carried by the throwing blades 9.

distance approximately 180 before leaving the outer ends of the blades to impinge the work W.

The point of discharge of the thrown abrasive varies with the length of the abrasive throwing blades as well as the speed of rotation of the wheel. It will be noted by referring to Fig. '7, that the studs 3 are positioned inwardly of the wheel periphery and directly behind the throwing blades b so that the studs are beyond the path of the rebounding abrasive a or the lagging abrasive a. The only parts subject to wear, therefore, are the removable and replaceable blades 17 and the side wall discs l and 2. The side wall discs I and 2 may be made of heavy wear resisting steel and are not seriously injured by the impinging action of rebounding or lagging abrasive. Thus, any abrasive which might rebound from the work surface W, or which might lag behind one of the throwing blades, will be caught by the following throwing blade and thrown against the work surface without doing serious damage to the permanent parts of the wheel.

It will be noted that air will circulate around the tubular control member ill and the inner ends of the blades b freely and without obstruction. There are no internal pockets wherein vacuum or pressure conditions can be built up during the rapid rotation of the wheel which conditions might influence the normal desired movement of the abrasive through the wheel. More accurate control of the thrown abrasive and a considerable decrease in horsepower consumption is realized as a result. It will also be noted that the advancing face portion I00 of the channel shaped blade lies in a direct radial line drawn through the axis of rotation of the wheel. The abrasive moves on to the inner ends of the blades evenly and uniformly and is subject to more delicate control of the direction of flight of the thrown abrasive and more even distribution and more uniform intensity of impingement against the work surface is attained.

It is recognized that increased wear on one side of the wheel more than the other may result in throwing the wheel out of dynamic balance. 70 With the wheel as herein constructed the wheel is not as susceptible to over-balancing due to the fact that the heavy side wall members i and 2 are evenly balanced and the moving abrasive is kept out of wearing contact therewith. Over- 75 balancing may result, however, if one side of the throwing blades should be more seriously affected by the moving abrasive than the opposite side of the blades. Should the throwing blades wear unevenly, it is preferable to remove all the blades and to replace them with a new set of matched and balanced blades. The old blades which are partly worn may be saved andlater matched with other blades until a matched set of partly worn blades has been collected. These partly worn balanced blades can then be inserted into the machine and used until their useful life has been expended.

The machine is adapted for a variety of different uses and will operate efliciently with moist or wet abrasive, which is a constant source of difficulty where air blast equipment is used. The machine may be mounted upon any suitable standard or may be associated with any conveyor apparatus or tumbling mill. The machine is made of few parts, may be inexpensively manufactured and assembled, is strong and durable in construction, substantially foolproof in operation. requires little floor space and is highly efflcient.

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 ing from the spirit of the invention.

What is claimed is:

1. An abrasive throwing wheel including in combination, spaced rotatably mounted side wall members, channel shaped throwing blades radially arranged between said side wall members and ex ending inwardly short of the axis of rotation of said wheel to define a central abrasive receiving space, a feed device for directing abrasive into the path of rotation of said blades, and spaced shouldered stud elements providing the sole means for connecting said side wall members in fixed spaced relationship. I I

2. An abrasive throwing wheel including in combination, spaced rotatably mountcd side wall members, a removable and replaceable throwing blade including a bottom wall portion and side flange portions positioned between said side wall members and extending inwardly short of the axis of rotation of said wheel to define a central abrasive receiving space, shoulder portions projecting from said side wall members overhanging the side flange portions of said blade, means for retaining said side flange portions in abutting position against said shoulders, and means for conducting the abrasive into the path of rotation of said blades.

3. A rotor for throwing abrasive at a blasting velocity including, spaced rotatably mounted side wall members, paired grooves in said side wall members radiating outwardly, channel shaped throwing blades extending between said side wall members and into said grooves, means for removably securing said blades in operative position, studs "securing said side wall members in fixed spaced position, and means for directing a stream of abrasive off center into the path of rotation of said blades.

4. An abrasive throwing wheel including in combination, rotatably mounted side wall members, removable and replaceable channel shaped throwing blades positioned between said side wall members, the side edges of said blades seating within correspondinggrooves on the inside faces within said wheel.

5. A rotor for throwing abrasive at blasting velocities including in combination, spaced rotatably mounted side wall members, means for retaining said side wall members in fixed spaced relationship, channel shaped throwing blades positioned between said side wall members and radiating outwardly, shoulders associated with said side wall members for supporting said blades, means for removably retaining said blades in fixed position, and a feed device for directing a contracted stream of abrasive into the path of rotation of said blades.

6. A rotor for throwing abrasive at blasting velocities including in combination, rotatably mounted channel shaped throwing blades extending inwardly short of the axis of rotation of said wheel to provide a central abrasive receiving space, and a tubular control member positioned within said central space having a discharge out- 90 let in the side wall thereof, means for forcing abrasive out through said discharge outlet onto the inner ends of the blades longitudinally of the blades and into the path of rotation thereof, said discharge outlet including a plurality of spaced discharge openings for producing substantially even distribution of the abrasive thrown by the rotating blades.

7. A rotor for throwing abrasive at blasting velocities including in combination, radially spaced, rotatably mounted channel shaped throwing blades extending inwardly short of the axis of rotation of said-wheel to provide a central space, a tubular control member positioned within said central space having a discharge outlet in the side wall thereof, and a rotatably mounted impeller for forcing abrasive fed into the path of said impeller out through said discharge outlet onto the inner end of the blades longitudinally of the blades and into the path of rotation thereof, said discharge outlet including a plurality of spaced discharge openings, said openings increasing in area in the direction of rotation of the wheel whereby substantially even distribution of the abrasive over the work is effected.

8. A wheel for throwing abrasive at blasting velocities including, spaced side wall forming members, shouldered stud elements connecting said members in fixed spaced relationship, channel shaped throwing blades positioned between said members and arranged in advance of said stud elements to protect said stud elements from abrading contact with rebounding and lagging abrasive, means for removably securing said hi: des in position, and means for feeding abrasive into the path of rotation of said blades.

9. A wheel for throwing abrasive at blasting ve'- locities including, rotatably mounted side wall members arranged in fixed spaced relationship, channel shaped throwing blades positioned between said members, shoulder portions associated with said side wall members for supporting said blades, each of said blades having the advancing face thereof arranged in a radial line and means for feeding abrasive into the path of rotation of said blades.

10. A rotor for throwing abrasive at blasting velocities including in combination, spaced rotatably mounted throwing blades extending inwardly short of the axis of rotation of the wheel to provide a central space, a tubular control member positioned within said central space having a discharge outlet in the side wall thereof, an impeller mounted to rotate with said wheel for forcing abrasive out through said discharge outlet and into the path of rotation of said blades, said discharge outlet including a plurality of spaced discharge openings arranged in alignment for producing substantially even distribution of the abrasive thrown by the rotating blades.

11. A rotor for throwing abrasive at blasting velocities including in combination, spaced rotatably mounted throwing blades extending inwardly short of the axis of rotation of the wheel to provide a central space, a tubular control member positioned within said central space having a discharge outlet in the side wall thereof, an impeller mounted to rotate with said wheel for forcing abrasive out through said discharge outlet and into the path of rotation of said blades, said discharge outlet including a plurality of aligned spaced discharge openings encompassed within an arc of less than 180 for producing substantially even distribution of the abrasive thrown by the rotating blades.

12. A rotor for throwing abrasive at blasting velocities including in combination, spaced rotatably mounted throwing blades extending inwardly short of the axis of rotation of the wheel to provide a central space, a tubular control member positioned within said central space having a discharge outlet in the side wall thereof, an impeller mounted to rotate with said wheel for forcing abrasive out through said discharge outlet and into the path of rotation of said blades, said discharge outlet including a. plurality of aligned spaced discharge openings encompassed within an arc of less than 90 for producing substantially even distribution of the abrasive thrown by the rotating blades.

VERNE E. MINICH.

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