US2204634A - Abrasive-throwing wheel - Google Patents

Description

June 18, 1940. D. c. TURNBULL ABRASIVE THROWING WHEEL Original Filed Nov. 17, 1936 2 Sheets-Sheet 1 llhll INVENTQR flaw'a 6. ikmall BY lav/1114 W WM ATTORNEY June 18, 1940. ,TURN U| L 2,204,634

ABRAS IVE THROWING WHEEL Original Filed Nov. 17, 1936 2 Sheets-Sheet 2 Q A 1 Q} lNVENTO R s flaw'a 6. Zia/Mull WM 4 My ATTORNEY Patented June 18, 1940 UNITED STATES azoam ABRASIVE-THROWING WHEEL David 0. 'rambuu, Mis

hawaka, Ind., assignor to American Foundry Equipment Company, Mishawaka, 11111., a corporation of Delaware Original application November 1'7, 1936, Serial No 111,212. Divided and this application February 9, 1937, Serial No. 124,815

6 Claims. (01. 51-9) This invention relates to abrasive-throwing wheels, and more particularly to improved throwing blades for use in such wheels.

This application is a division of my copending application, Serial No. 111,212, filed November 17,

Abrasivethrowing wheels in general used in the cleaning of metallic castings, forgings, bars,

billets, sheets and like materials, operate to throw under directional control'and against a surface to be cleaned, the abrasive material which generally comprises cracked steel grit, steel shot, or quartz sand. The abrasive-throwing wheels must be rotated at a speed suflicient to hurl the abrasive from the wheel at velocities of 9,000 to 16,000 feet Der minute. It is desirable that the wheel be so constructed as to permit a smooth and uniform flow of the abrasive through the wheel and that such parts of the wheel as come into, contact with the abrasive should be composed of a material which is as resistant as pos-' sible to the eroding action of the abrasive.

Structurally,the abrasive-throwing wheels now in commercial use comprise a series of throwing blades generally of channel form, which extend from the periphery of the wheel inwardly short of the rotating axis of the wheel so. as to define a central space or opening. Directional control of the abrasive is accomplished by the provision of a tubular control member which extends into the central opening and is provided with a discharge opening in the circular wall thereof of predetermined but limited peripheral length. Suitable means, such as an impeller, comprising a series of radially arranged vanes, project the abrasive fed into the tubular control member through the peripheral opening thereof. The impeller is preferably mounted to rotate with the blades, the tubular control member normally remaining stationary'during rotation of the wheel but otherwise adjustably mounted so as to control the direction of flight of the abrasive thrown from the wheel. The blades may be rotatably supported or mounted upon a side wall plate or a pair of spaced side wall plates, as desired, the side wall plates being connected to the drive shaft.

My improved blades are preferably mounted substantially along a radial line extending from the axis of rotation of the wheel, and are each provided with a relatively thin lip portion which extends forwardly or in the direction of rotation of the wheel. The thin lip operates to clean- 1y scoop up the abrasive ejected from the discharge opening in the control member and permits it to pass along the advancing face of the ,portion is so shaped and designed that blade. Since the greatest wear on the blades occurs along the outer end of the blades due to the increasing speed of the abrasive moving thereacross, I preferably gradually increase the thickness of the blades from a point adjacent the lip portion to the outer end of theblades; The lip the abrasive is given little or the inner end of the blades and rebound inwardly against theouter surface of the tubular control member, but .is required to pass either onto the advancing face of the adjacent blade passing over the discharge opening of the control member, or otherwise passing to the rear of said blade and then onto the advancing face of the next succeeding blade. Thus a smooth and even flow of abrasive through the wheel is obtained. The side wall plates, if the --wheel is properly constructed, receive .very little, if any, wear due to the fact that the abradant is confined within the side walls of the channel-shaped blades in its passage from the opening of the control member to the periphery of the wheel. Any sidewash of the abradant along one side edge of the blade is also substantially limited due to' the action of the lip portion of the blade in distributing the abradant evenly over the advancing face thereof.

' An object of this invention is to provide an improved abrasive-throwing blade adapted to be associated with an abrasive-throwing wheel, which is so designed as to pick up the abrasive from the abrasive-discharge outlet adjacent the center of the wheel substantially without spattering, which blade possesses great strength and wear resistance where eroding action of the abradant is greatest, and which is conducive to a smooth and uniform flow of the abradant over the surface of the blade.

Various other features and advantages of the invention will be apparent from the following particular description and from aninspectlon of the accompanying drawings.

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 re, ferring to the following description taken in connection with the accompanying drawings forming a part thereof, in which Fig. 1 is a side view of theabrasive-throwing wheel as it appears when assembled; this view showing'my improved abrasive-throwing blade no opportunity to strike positioned within the wheel, certain parts being broken away more clearly to illustrate the construction;

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

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

Fig. 4 is an enlarged fragmentary perspective view showing a portion of the tubular control member and the adjacent ends of the throwing blades;

Fig. 5 is a perspective view of my improved throwing blade lookingat the advancing face thereof; and

Fig. 6 is a perspective view of the throwing blade looking at the rear face thereof.

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

The abradant used in abrasive-throwing wheels necessarily must posses a high cutting or abrading efiiciency in order to economically and satisfactorily clean, polish, harden, or otherwisetreat hard metallic surfaces, such as castings, forgings, billets, bars, sheets, and like materials, which materials are generally coated either with a very hard blue scale or with hard crusty matter adhering to the surface of -the metal after casting, forging, or rolling the same. To remove this undesirable scale and foreign matter successfully it will be appreciated that an unusually hard abradant material must be used projected against 'the surface to be cleaned at abrading velocities. In ordinary cleaning operations. either cracked steel grit, steel shot, or hard quartz sand or vari-' ous mixtures thereof, is used as the abradant. Where an abrasive-throwing wheel is used to project the abradant, such wheels must be rotated at very high speed in order to project from the wheel the abradant material at satisfactory abradant velocities ranging generally from 9,000 to 16,000 lineal feet per minute. By way .of example, successful abrasive-throwing wheels have been constructed having a diameter of approximately 20 inches, which wheels are rotated at speeds from 2,000 R. P. M. to 3,000 B. P. M. and upward to transmit to the abradant the desired abrading velocity. In wheels of approximately twenty inches in outside diameter, tubular control members have been used varying in diameter from approximately four inches to approximately nine inches and over, and the blades of such wheels have consequently varied in radial length from approximately five to approximately eight inches. It will'be appreciated that at such high velocities as above mentioned the abradant exerts a considerable eroding action on such I parts of the wheel which come into contact with the abradant, and particularly those parts which are farthest removed from the axis of rotation. This abrading action is particularly severe on the throwing blades and particularly towards the outer ends thereof.

While such abrasive-throwing wheels have already found an accepted' place in. the foundry and steel industries, it is appreciated that further efficiencies and economies can be achieved if the parts of the wheel most severely subjected to the action of the moving abradant are made of wearresistant metal and also so constructed that they are able to withstand the wearing, effect of the abradant aswell as the shocks, impacts and abuse incident to operation, and further so constructed as to move the abradant smoothly and evenly over the surface h reof. Thus y increasing the life may comprise a rear side wall disc I and a front side wall disc 2 connected together by a plurality of stud elements 3 suitably secured to the side wall discs I and 2. rotatable shaft 4 having a hub 5 connected by means of bolts 6 to the disc' I. My improved throwing blades .b extend from the periphery of the wheel inwardly short of the rotating axis so as to provide a central openingor chamber 0. Each blade is formed from a hard wear-resisting material which will be presently described, each blade generally comprising a bottom portion I00 and side fiange portions IOI, providing a channel-shaped member adapted to retain the abrasive therein as it moves across the face thereof.

The flange portions IOI of the blade may be arranged to seat within corresponding grooves I provided in the side wall discs I and 2 of the wheel. Removable screws 3| provided with inner tapered portion 32 project through the side wall discs I and 2, and engage the under surface of the blades b to retain the blades in fixed position within the wheel, with the flanges MI in abutment against the overhanging shoulders 8. The

blades may each be provided with a grooved recess I02 into which the tapered end of the screws 3I project.

A tubular control member I0,. which may have an inwardly extending flange I I at the inner end thereof, extends into the central chamber 0. The control member i0 is mounted independently of the throwing blades b and the side wall discs I and 2 on a suitable support I2, on which it may be adjusted rotatively about the axis of the wheel structure. An impeller is mounted within the control member and fixed to rotate with the Wheel. The impeller may comprise a. rear side plate I5 and a front side plate I6 connected by a plurality of radiating impellervanes H. The impeller may be connected to rotate with the wheel by means of a bolt I8 which screws into the blade centering plate I9 fixed to the rear side wall disc I by means of screws 2 I. Abrasive fiows from a feed-pipe 50 into the impeller through the center opening 22 in the front side plate I0 of the impeller. The abradant drops radially across the impeller vanes I1 and is then whirled within the tubular control member I0 until'discharged through the discharge opening 0 therein, The abradant is thrown out through the discharge opening 0 with considerable force across the inner ends of the blades b and into the path of rotation. thereof. It will be noted that since the impeller rotates with the blades at substantially the same speed, the abrasive moves gently onto the advancing face of the blades without destructive, shock to the abrasive or to the inner ends of the blades. The abrasive gains momentum asit moves across the face of the blades and is thrown from the'outer ends of the blades with great force. Under the same operating conditions, a fixed relationship exists between the clock dial position of the discharge opening 0 in the control member I0 and the clock dial position of the arc of discharge from the wheel. By adjusting the position of discharge opening 0, the direction of the abradant thrown The wheel is mounted on aby the wheel may be regulated and controlled. The position of the discharge opening is adjusted by rotating the control member I0 and adjusting it on its. support I2 so that the discharge opening is brought to the position desired.

An important feature of this invention comprises the shape of the throwing blades b which are shown more particularly in Figs. 4 and 5. It will be noted thatthe inner ends of the blades are provided with'a relatively thin lip portion I03 which extends at approximately an angle of 45 from the advancing face of the bottom portion I00 of the blades. The free edge of the lip I03 extends relatively close to the exterior surface of, the tubular control member I0, sufficient space being allowed for free clearance only. The lip I03 extends from the control member .I0 in the direction of rotation of the wheel. The back surface of the lip I03 is beveled as at I03b with respectto the back face of the blade,-

and the front face I03a of the lip is beveled and slightly rounded so as .to smoothly roll into the advancing face of the bottom portion I00 of the blade.

The thin lip I03 serves to out the abrasive stream discharging from the discharge opening 0 of the control member I0 so as to avoid any interference with the. free movement of the abrasive onto the advancing faces of the blades. The inner end of the blade lip I03 is preferably approximately only A; to of an inch or less in thickness so that the abrasive ejected from the discharge opening 0 has little or no opportunity to be deflected by the inner end of the lip I03 inwardly against the outer surface of the tubular control member. Thus, the abrasive discharged from the opening 0 either passes clear of or glides in contact with the advancing face I03a of the lip,

or passes under the rear face I03b of the lip, from whence it will pass directly onto the advancing face of the succeeding blade. Thus, inward spattering of the abrasive is avoided. Also, the construction of the blade above described is conducive of a uniform spread of the abrasive over the entire width of the blades, avoiding a. sidewash of the abrasive along one side of the blade as it moves over the same. Sidewash is further prevented by tapering the inside face IOIa of the side walls IOI for a distance adjacent the inner end, as shown in Fig. 5. The tapered surfaces IOIa of the side walls IOI assist in distributing the abrasive deposited onto the advancing face of the blade uniformly over the width of the advancing blade surface.

It is known. that the eroding effect of the abrasive increases as its speed or velocity over the blade increases, resulting in greater wear of the blade at the outer end thereof. The life of the blade can be materially increased by gradually increasing the thickness of the blade toward the outer end thereof. As shown more particularly in Figs. 1, 4, 5 and 6, the blade bottom I00 gradually increases in thickness from adjacent the inner end where it may be approximately to of an inch in thickness to the outer end of the blade where it is approximately 1 of an inch in thickness. Tests have indicated that the lip I03 approximately of an inch in thickness, as well as the inner end of the bottom I00 approximately to of an inch in thickness, will last as long as the outer end of the blade having a bottom wall thickness of approximately of an inch. Tests have further illustrated that when the blade is also made of material about to be described, a blade life of from to opening 0.

face of the blade with increasing velocity, the

100 hours of operation, and over, may be realized.

The wearing parts of the abrasive-throwing wheel. such as the impeller vanes H, the tubularcontrolimember I0, and particularly the abrasive-throwing blades b, should be formed from a composition containing pure iron intermixed with various compounds providing a metallic composition highly resistant to abrasive wear. yet tough and able to withstand the impact and shocks incident to operation. The metal should further possess a high degree of structural uni formity so that wear will occur in the material smoothly and uniformly. I

. An impeller vane I1 is provided for each blade and, as shown in Fig. 4, eachof the impeller vanes rotate at the same R. P. M. as the blades, the

vanes I'll throw out a load of abrasive a through the opening 0 just in time to be scooped up by the lip I03 as the abrasive a emerges beyond the The abradant then moves over the blade bottom I00 being correspondingly thickened towards the outer end of the blade so as to withstand the increasing wear. As thus constructed, the outer end of the blade will be worn to the point of uselessness about the time that the lip I03 is worn to the point where satisfactory operation can no longer be obtained. Thus, it is seen that a blade is provided which wears out substantially uniformly throughout its length, obtaining maximum abrading efflciency from the blades. l

Whilecertain 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 blade adapted for use in centrifugal abrasive throwing wheels of the character including a rotor adapted to be rotated at high speed and carrying a plurality of radially extending, channel-shaped, throwing blades along which the abradant may be accelerated, with means for feeding abradant onto the inner ends of the blades, said blade being formed from metal of uniform molecular structure resistant to abrasive uniformly in thickness from the base of said lip portion to the outer end of the blade, the inside faces of said side wall portions being substantially of the rotating axis of the wheel and means for parallel over the major length of the blade, the i -uniform molecular structure and resistant to abrasive wear and comprising a bottom wall portion, substantially similar straight side wall portions of substantially uniform width throughout operative to retain the moving abradant within the channel confines thereof, said side wall portions presenting substantially fiat parallel outside faces and substantially square cut ends, the outside face of said bottom wall portion having an inner end area tapered forwardly in the direction of rotation to present a relatively fine abrasive receiving edge, said bottom wall portion increasing substantially uniformly in thickness from the base of said tapered area to the outer end of the blade, one of said side wall portions having a notch of arcuate contour cut in the lower outside edge thereof adapted to receive a blade retaining element.

3. A blade for use in an abrasive throwing wheel of the type including channel-shaped throwing blades extending from adjacent of the periphery of the wheel to inwardly short of the axis of rotation and means for supplying an abradant to the inner ends of said blade, said blade having a bottom wall portion and substantially similar straight abrasive retaining side wall portions formed from a metal of uniform molecular structure resistant to abrasive wear, said side'wall portions being of substantially uniform width throughout and presenting substantially flat parallel outside faces, and a lip portion at the inner end of said bottom wall portion having a concavely curved leading face and a beveled trailing face extending forwardly in the direction of rotation of the wheel, said bottom wall portion increasing substantially uniformly in thickness from the base of said lip portion to the outer end of the blade, one of said side wall portions having a notch of arcuate contour cut in the lower outside edge thereof adapted to receive a blade retaining element.

4. A blade adapted for use in centrifugal abra sive throwing wheels of the character including a rotor adapted to be rotated at high speed and carrying a plurality of radially extending, channel shaped, throwing blades along which the abradant may be accelerated with means for feeding abrasive onto the inner ends of the blades, said blade having a bottom wall portion and substantially similar straight abrasive confining side wall portions formed from a metal of uniform molecular structure resistant to abrasive wear, said side wall portions being of substantially uniform width throughout the length of the blade, said side wall portions presenting substantially flat and parallel outside faces and substantially square cut ends, the outside face of said bottom wall portion havingan inner end area tapered forwardly to present a relatively fine abrasive receiving edge, the remaining area of said outside face of the bottom wall portion being substantially flat, said bottom wall portion increasing substantially uniformly in thickness from the base of said tapered area to the outer end of the blade, one of said side wall portions having a notch of'arcuate contour cut in the lower outside edge thereof adapted to receive a blade retaining element.

5. A blade adapted for use in centrifugal'abrasive throwing wheels of the character including a rotor adapted to berotated at high speeds and carrying a plurality of radially extending throwing blades along which the abrasive thrown may be accelerated, with means for feeding abrasive onto the inner ends of theblades, said blade having a bottom wall portion and substantially straight side wall portions operative to retain the abradant Within the channel confines thereof, said side wall portions presenting substantially flat and smooth outside faces and substantially square cut ends, the outside face of said bottom wall portion having an inner end area tapered at an angle of approximately 45 in the direction of rotation to present a relatively fine abrasive receiving edge, the remaining area of said outside face of the bottom wall portion being substantlally flat and co-planar with the lower edges of said side wall portions, said bottom wall portion increasing substantially in thickness from the base of said tapered area to the outer end vof the blade, the inside faces of said side wall portions being substantially parallel over the major length of the blade, the inside faces of said side wall portions adjacent the inner end of the blade being flared to facilitate movement of the abrasive onto the advancing face of the blade.

6. A blade adapted for use in centrifugal abrasive throwing wheels of the character including a rotor adapted to be rotated at high speeds and carryinga plurality of radially extending throwing blades along which the abrasive thrown may be accelerated, with means for feeding abrasive onto the inner endsof the blades, said blade having a bottom wall portion and substantially similar straight side wall portions operative to retain the abradant within the channel confines thereof,. said side wall portions presenting substantially flat and smooth outside faces and substantially square cut ends, the outside face of said bottom Wall portion having an inner end area tapered at an angle of approximately 45 in the direction of rotation to present a relatively fine abrasive receiving edge, the remaining area of said outside face of the bottom wall portion being substantially flat, said bottom wall portion increasing substantially in thickness from the base of said tapered area to the outer end of the blade; the inside faces of said side wall portions being substantially parallel overthe major length of the blade, the inside faces of said side wall portions adjacent the inner end of the blade being flared to facilitate movement of the abrasive onto the advancing face of the blade.

DAVID C. TURNBULL.

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