US2301508A - Abrasive throwing wheel - Google Patents

Description

Nv. 1o, 1942. T BLOUNT 2,301,508

ABRAS IVE THROWING WHEEL Filed March 14, 1939 2 sheets-sheet 1 SYM/mu ATTO l2 N EY 2 sheets-sheet 2 ATTO RNB H. T. BLOUNT yArsmsrvs THRowING WHEEL Filed March 14, 1939 Nov. 10, 1942.

Patented Nov. 10, 1942 ABRASIVE THROWING WHEEL Herbert T. Blount, Los Angeles, Calif., assigner to Mills-Alloys, Inc., Los Angeles, Calif., a corporation of Delaware Application March 14, 1939, Serial No. 261,742

7 Claims.

This invention relates to an abrading device of the type wherein the abrasive is in granular or shot form and is discharged from a rapidly rotating head or wheel by centrifugal force against the article to be abraded. This application is a continuation in part of an application for patent Serial No. 210,916, filed May 31, 1938, in the name of Herbert T. Blount, entitled Abrasive Blast.

In general, such abrading devices have been proposed and used in the past. The rotating head or wheel is commonly provided with means forming passages, extending from near the axis toward the periphery, through which the shot or abrasive passes as the Wheel is rotated. The abrasive may be fed to the inner ends of the passages by any suitable feeding device, the inside surface of the passage contacting the material so that the rotating motion of the passage about the axis of the head is imparted to the material. Thus, the inertia of the abrasive particles causes them to contact the wall with considerable force, since the motion of the contacting surface is quite rapid. The rotary motion imparted to the particles causes centrifugal force to urge them outwardly along the passage. The passage forming means being subject to severe Wear, the life thereof is very short, since the passage is soon so worn as to render diiiicult or impossible, the attainment of optimum inertia eifects.

It is a principal object of this invention to provide a wheel including means to prevent the abrasive from contacting the head or wheel itself, thereby materially increasing the length of useful life of the wheel. This object is accomplished by providing the passages and other surfaces of the wheel contacting the abrasive with a lining or facing of wear resisting material, such as tungsten carbide, or other hard alloy of abrasion resisting quality.

It is a still further object of this invention to provide a wheel of the character described having anovel arrangement of nozzle structures in the Wheel whereby the angle of distribution of the abradant may be accurately controlled.

It is another objectA of this invention to render it possible to use the head or wheel for a greatly extended life by providing replaceable facings or linings for the parts subject to abnormal Wear.

It is still another object of this invention to provide an abrasive throwing wheel or head permitting the use of relatively large discharge nozzles, at the same time maintaining the axial inlet space at a reasonable or conventional diameter.

It is a still further object of the invention to provide such a wheel or head which takes advantage of the exhaust fan action of the rapidly revolving wheel to assist'in discharging the abrasive.

It is still another object of this invention to provide a replaceablenozzle of improved construction, whereby the nozzle lining is retained in position in the Wheel, even though the lining becomes checked or cracked.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the drawings accompanying and forming part of the present specification.l These forms, which illustrate the general principles of the invention, will now be described in detail; but it is to be understood A that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined In the drawings:

Figure 1 is a fragmentary elevation, partly in section, showing Aan abrading wheel embodying one form of the invention;

Fig. 2 is a section as seenl substantially on plane 2-2 of Fig. 1; p

Fig. 3 is an isometric view of a portion of the abrasive receiving cage of the wheel shown in Fig. 1;

Fig. 4 is an isometric View of one of the wear resisting plates of the cage of Fig. 3;

Fig.` 5 is a View similar to Fig. l, but showing a modied form of wheel;

Fig. 6 is a sectional view showing an installation of the wheel. arranged for use; and

Fig. '7 is a fragmentary sectional view showing a modified form of nozzle.

Referring to the form of wheel shown in Figs. 1 to 4 inclusive, the wheel I0 includes a frame or head II secured to a rotary shaft I2 so as to be driven thereby (Fig. 6). The wheel I0 is arranged to provide a central space I3 for the reception of the abrasive material, and has a plurality of nozzle structures I4 extending outwardly from this space to the periphery of the wheel. With the wheel I0 rotating, any material fed into the central space I3 will be discharged through the nozzles I5 by centrifugal force. Since this rotation is usually at such a rate that the peripheral speed of the wheel is of the order of 10,000 feet per minute, this material passes out of the nozzle at -a high velocity.

The wheel IB is shown as supported for rotation in the `upper portion of a closed housing I5 Vby the appended claims.

(Fig. 6) which may be provided with a grate I6 some distance below the wheel I where the work to be abraded or cleaned is placed. The abrasive material may be fed from any suitable source, as through a chute I'I discharging into a feeder I3 leading into the central space I3 of wheel I0. This feeder I8 may include valving means which feeds the abrasive material to the central space I3 only over a limited sector of the plane of revolution of the wheel IIlI. By this means, the angle through which the discharge occurs from the periphery of the wheel I6 is limited approximately to the length of the grate I 6. Several forms of such feeders are well known in the art.

The abrasive is usually finely divided, hardA material, which may or may not have sharp edges. the like, of the order of 20-mesh, and known as shot, or any of various other materials, as carborundum or sand, may be used, depending on the work to abraded. Since any abrasive that is likely to be used isvhard enough to cause rapid wear of these wheels as usually constructed, such wheels have an extremely short life.

In the present wheel.y all parts whichV are subject to Wear by the moving abrasive are lined or faced with a hard, wear resistant material, such as tungsten carbide.0 Furthensinceonly a part of the nozzle boreis subject to wear by the abrasive as it leavesthe wheel, thelife. of the nozzle can` be increased by making provision to alter the positionY of the nozzle4 so as to replace the worn part of the bore with adifferent, and unworn, part. Also, by making thenozzles and other parts which are subject. to wear, replaceable, the wheel or frame can be used. indefinitely.

Referring to. Figs. 1 and.2, thefra-me I-Iy com.-

prises afpair of circular plates or flanges 21|.V andy 22, appropriately joined to inner and outer rings, 23 and 24 respectively. Thus, these plates 2| and 22 may be separately fabricated and joined, as by welding, or the head may be cast as a single piece. One of the plates, as 2-I, has a central, counterbored recess 25, in which is secureda hub 26, as by cap screws or bolts 2'I. The hub 26 is fastened to shaft I2 in any suitable manner, so that the frame II is rotated and supported by the shaft I2.

The inner` and outer rings 23 and 24 are provided with a plurality of bores or openings 29 and 3Q symmetrically spaced about the axis of the frame II, to receive. the nozzle structures I4. Each nozzle structure I4 includes an inner sleeve or lining 3l made from some wear resistant material, as tungsten carbide, and an outer jacket or shell 34 of relatively soft metal, as for example an alloy suitable for die casting, or brass. The sleeve 3l being ofv very hard material, is brittle and permits of rno machining other than by grinding. Byy providing the soft metal jacket 34` the nozzle structure as awhole has the requisite strength. Further, the jacket can be readily machined if necessary, as for example to finish the outer end to a reduced diameter, as indicated at 35 to provide a shoulder 36.

Each ofY the bores 30 in the outer ring 24 is provided with a counterbore 40 to receive shoulder 36 of the associated nozzle I4 and hold it .against displacement by centrifugal force due to Thus, small pieces of tungsten', steel, or

in the event of the lining 3| checking or cracking, the outside of the lining 3| is tapered from one diameter at the inner end 32 to a slightly smaller diameter at the outer end 33. Since for convenience in manufacturing, the lining 3I is of uniform thickness, the inside of the nozzle i4 also has a slight taper, but this is unimport- .tant. However, as will appear presently, it is preferable that the nozzle opening at the outer end of the nozzle be not materially greater, and preferably slightly smaller, than that at the inner end.

As will be noted from an inspection of Fig. lJ the inner ends 32 of the nozzles I4 are about as close together as it is possible tol arrange them. At thesame time, they are so far distant from the axis of rotation as to require a separate device forproper feeding of the abrasive material. Hence, a cage 3l (Fig. 3) is arranged in the central space I3 having a plurality of blades 38, each of which forms in eifect a continuation of one of the nozzles. Cage 3l (Fig. 3) is formed of an outside annular plate 39 with an outer diameter substantially the same as the inside diameter of ring 23, and the diameter of the central space I3, and with an inner periphery I4 of suitable sizeto accommodate an appropriate feeder. Outsideplate 39 is joined by blades 38 to a similar inside plate 4I, the outer periphery of which is out away as at 42 to provide clearance for the inner ends of the nozzle structures I4 when the platelll is slid axially into position. If desired for convenience of assembly, each ring or plate 33, 4I, is out into segments, the outer length of which corresponds closely to the outside diameter of nozzles I4. Thus, cage 3l consists of a number of exactly similar sections Il,.correspond ingin. number to the number of nozzles I4, each sectionv consisting of an outsidel and an inside segment 43. and 44, joined. by a bladel 33.

Since, as before mentioned, each blade 38forms in eifect an inward continuation of a nozzle I4, itV follows that the bladeV 38 must. receive the abrasive from the feeder IB and impart the rotary motion of the Wheel II) to it. The blade 38 is thus subjected to very severe wear, and to protect it, a wear plate or facing 45 (Fig. 4) of wear resisting material, as for example, tungsten carbide, is provided on its advancing face.

As clearlyl shown in Figs. 1, 3 and 4, wear plate 45 is rectangular and of greater thickness along one edge as 46 than the other. It is provided with a centralarcuate cavity 4'I,.Which substantially matches the bore of nozzle lining 3| where plate 45 contacts the nozzle I4. Each segment of the annular plates 33 and 4I has tapered set-back edges 48^and 49 to accommodate the wear plates 45 which are arranged with their wide edges against the respective nozzles I4. This serves to keep them from moving outwardly, while the tapered edges keep them from falling inwardly. Further, each of segments 43 has a portion 'I2 which extends over the wide edge 46 of the associated plate 45 to assist in holding the plate 45 in proper position.

In the form of the invention shown in Fig. l, the nozzles I4 are so positioned that the most rearward element of the bore of the lining 3i (with regard to the direction of rotation) falls on a radial line of the frame I i. Thus, that portion of the nozzle bore indicated by 5I) which carries the abrasive, is quite closely radial. makes possible a more accurate control of the angle of distribution of the abrasive by the wheel. It will be noted that the rear portion 52 of the This nozzle I4extendssome distance through the inner ring 23 while the forward portion 53 does not reach it, leaving an opening 54. To close the opening left thereby, use is made of ring 55 which fits over the nozzle lining 3| and rests on the inner end of the jacket 34. The inner face of this ring 55 is Vat a considerable angle with its axis; thus one side, as 56, of the ring is longer than the other side 51. The short side 51 is intended to be disposed under blade 38, while the long side serves to close opening 54. The exposed portion of the ring 55 above the nozzle lining is never subjected tothe abrading action of the material which the wheel I is handling, hence is not subjected to any wear.

The procedure of assemblingv the wheel I0 is as follows: Each nozzle structure I4 is inserted into its'supporting bores 29 and 38 from the central space I3, and shoulder 36 is seated in counterbore 4I). The rings 55 may be inserted with their respective nozzles I4, or they may be inserted subsequently. In either case, they are positioned about their axes so that their long sides 56 will clear the next nozzle I4. After each ring 55 has been seated against the end of the respective jacket 34, it is rotated to bring the long side 56 in proper position to cover opening 54. The segments 1I of the cage 31 are then inserted, a dowel pin 58 on the inner plate 4I of each segment 1I engages a hole 59 in the backplate 2I of the frame and serves to hold the segment 1I in position. Since at least some of the segments 1I must be inserted by sliding the segment axially with respect to the wheel and along the inner end of the corresponding nozzle I4, the inside plate 4I of each segment 1I is cut away as indicated at 42. That is, plate 4I is cut away to clear the inner end of nozzle lining 3I as well as ring 55 (see Fig. 1). Obviously, it is not essential that the cage 31 be formed in sections, as it is perfectly possible to slide it axially into position if it is in a single piece.

After the cage 31 is completely assembled in place, a circular plate 60 is secured in a counterbore 6I formed in the outer plate 22 of the frame, as by countersunk screws 62. Then the cage segments 1I are secured to plate 60 by similar screws 63. Plate SII has a central opening 64 which is approximately the same diameter as the inside of the cage 31, through which abrasive material is fed to the wheel III.

The nozzle structures I4 are secured in the frame between the cage segments 1I and shoulders 48, but in order to secure them against any looseness as well as hold them in a denite position about their axes, a set screw 65 is provided for each nozzle I4. When one portion of the surface of the lining 3| becomes worn, the set screw 65 may be loosened and the nozzle I4 rotated to bring a different portion of the surface into wearing position.

To protect the periphery of the wheel Il) from wear by the discharged abrasive, as Well as the abrasive which rebounds from the work, the outside member 24 of the frame is surrounded by a tire 66, which may be replaced when it becomes worn, and which may be made from wear resisting material. To permit ready replacement, the tire is made in halves 61 and 68 which meet in the plane of the axes of the nozzles I4. The tire halves 61 and 68 are secured to the frame II in any convenient manner, as by screws 69. To avoid excessive thickness of the tire 66 and at the same time protect the nozzles I4 ade- 75 quately, the outside edges of the tire may be provided with rims or flanges 13.

In Fig. 5 is illustrated a modified form of wheel wherein the nozzles are arranged with their center lines radial. The construction of this wheel is similar to the other form. The Wheel includes a frame 15 formed of side plates 16 joined to inner and outer rings 11 and 18, the latter having alined bores 18 for the reception of the nozzle structure 80. Each nozzle structure includes a lining 8I of hard material and a soft metal jacket 82, the latter having a shoulder 83 resting in a counterbore 84V formed in the outer ring 18. Since the nozzles 80 are radial, it is possible to arrange them to extend entirely through the inner ring 11.

A cage 85 having blades 86 with wear plates 81 forming extensions of nozzles 80, similar to the cage in the first form, but shown as formed in a single unit instead of in segments is provided, the inclination of the blades 86 being such as to ensure proper delivery of the brasive to the nozzles.

A rapidly rotating wheel having blades or nozzles extending outwardly from its center, has a blower or exhaust fan action, the air being drawn from the central portion of the wheel and thrown out at the periphery of the wheel.

By arranging the nozzle structure so that the cross sectionall area of their inner ends is not substantially greater than that of theirV outer ends, use may be made of this moving air to increase the velocity of the discharged material'and to improve the eiciency of the wheel.

It may be desirable to provide additional reinforcement at the outer end of the nozzle lining. Thus, as shown in Fig. 7, a thimble of steel or other relatively strong material 90 may be provided over the soft metal jacket SI Since as before mentioned, the nozzle lining 92 is very difcult to machine, the jacket 9I is machined to some diameter which leaves a thin layer 93, only thick enough to provide an accurate surface and terminating in a shoulder 94. 'I'himble 90 is bored to nt this diameter and extends from shoulder 94 to the end of the nozzle. 'I'he thimble 90 in turn has a shoulder 95, which rests in a counterbore 84 formed in ring 18, and serves to support the nozzle before.

What is claimed is: y

1. A wheel for imparting motion to divided material comprising: means forming a central space adapted to receive the material, means forming a tubular nozzle of relatively large diameter extending from said space toward the periphery of the wheel, a cage within said space, said cage including a transverse blade extending from one side of the cage to the other side, said blade being arranged to form with at least a portion of the surface of the nozzle, a continuous surface.

2. A wheel for imparting motion to divided material, comprising: means forming a central space adapted to receive the material, means forming a nozzle extending from said space toward the periphery of the wheel, a cage within said space, said cage including a pair of spaced, substantially annular side members, a transverse blade joining said members, there being a wedge shaped slot, formed in each of said side members adjacent the blade, a plate of wear resistant material against the blades and mounted in said slots, said blade having inclined surfaces to cooperate with the surfaces of the slots, the sides of each slot respectively converging toward the axis of the wheel, one side of said plate forming substantially av continuation of at least a portion of the surface of the nozzle.

3. A Wheel forimparting motion to divided material, comprising: means forming a central space adapted to receive said material, a plurality of means forming tubular nozzles of relatively large diameter angularly spaced about the axis of the wheel and extending from the space tdward the periphery of the wheel a cage within said space including spaced side members joined by a plurality of vanes, each of said vanes being positioned adjacent a nozzle and including means forming with a portion o-f the surface of the bore of the associated nozzle, a continuous surface.

4. A wheel for imparting motion to divided material, comprising: means forming a central space adapted to receive the material, a plurality of means forming tubular nozzles of relatively large diameter angularly spaced about the axis of the Wheel and extending toward the periphery of the wheel, adjacent nozzles having their inner ends closely spaced, means forming a continuous surface with at least a portion of the driving side of each nozzle, from the inner'end of the nozzle toward the axis, whereby the said central space is of lesser diameter than the central space defined by the inner ends of the nozzles.

5. A wheel for imparting motion to divided material, comprising: a frame, a plurality of means forming nozzles angularlyspaced about the axis of the wheel and' extending toward the periphery of the Wheel, adjacent nozzles having theirinner ends closely spaced, said inner ends serving to dene a central substantially annular space, means forming a cage adapted to occupy said annular space and including vanes adapted to be joined to said nozzles, and to denne an axial space adapted to receive said material, and a member adapted to be secured to the frame as well as to the cage, whereby the cage and frame are held in assembled relationship, said member having an opening through which material may be fed into said axial space.

6. A wheel for imparting motion to divided material, comprising: a frame, a plurality of tubular nozzles angularly spaced about the axis of the wheel and extending toward the periphery of the wheel, said nozzles being of relatively large diameter, whereby their inner ends arespaced a substantial distance from said axis and dene a substantially annular space of large diameter, and means forming a cage in said space, said cage having vanes extending in a radial direction and cooperating respectively with the nozzles to form substantially continuous surfaces extending relatively close to said axis.

7. A wheel for imparting motion to divided material comprising: means forming a central space for receiving the material, and means forming a tubular-nozzle extending from the central space toward the periphery of the Wheel, said nozzle having a coned inner surface with its smallest diameter at the outer end of thevnozzle, a rearward element of said coned' surface being substantially radial with respect to the axis of the wheel.

HERBERT T. BLOUNT.

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