US3240632A - Throwing wheel vane - Google Patents

Description

March 15, 1966 E. 1.. HARTMAN ETAL 3,240,632

THROWING WHEEL VANE 6 Sheets-Sheet 1 Original Filed Sept. 10, 1962 INVENTORS Edward L.

Hartman Paviz 71f ffaom March 15, 1966 HARTMAN ETAL 3,240,632

THROWI NG WHEEL VANE 6 Sheets-Sheet 2 Original Filed Sept. 10, 1962 INVENTORS Edwwrdll flatrZ mm Ralph WMoo re March 15, 1966 HARTMAN ETAL 3,240,632

THROWING WHEEL VANE 6 Sheets-Sheet 5 Original Filed Sept. 10, 1962 INVENTORS fdwwrdlljfarimrz Ralph Wj foo 72? March 15, 1966 E. 1.. HARTMAN ETAL 3,

THROWING WHEEL VANE Original Filed Sept. 10, 1962 6 Sheets-Sheet 4 H u k E H x Q Q w% i March 15, 1966 E. HARTMAN ETAL 3,240,632

THROWING WHEEL VANE 6 Sheets-Sheet 5 Original Filed Sept. 10, 1962 INVENTORS Edwwrdllfwrimrz fiaqlpiz Wjifoom THROWING WHEEL VANE 6 Sheets-Sheet 6 Original Filed Sept. 10, 1962 QNQMH INVENTORS EdwardLHarZmw/a Ravk Wflbore United States Patent 3,240,632 THROWING WHEEL VANE Edward L. Hartman and Ralph W. Moore, Hagerstown,

Md, assignors to The Pangborn Corporation, Hagerstown, Md, a corporation of Delaware Uriginal application Sept. 10, 1962, Ser. No. 222,273, now Patent No. 3,151,417, dated Oct. 6, 1964. Divided and this application May 17, 1963, Ser. No. 281,179

6 Claims. (Cl. 148-3) This application is a division of application Serial No. 222,273, filed September 10, 1962, now U.S. Patent No. 3,151,417, issued October 6, 1964.

The present invention relates to a method for forming throwing wheels vanes used to project streams of particles against work pieces to subject the work pieces to cleaning, abrading or peening action or the like. A typical wheel of this kind is shown in U.S. Patent 2,869,289 granted January 20, 1959.

Among the objects of the present invention is the provision of improved methods for making such vane.

The above objects and further objects of this invention will be more completely understood from the following description of several of its exemplifications, and the accompanying drawings wherein:

FIG. 1 is a vertical section of a throwing wheel assembly having vanes exemplifying the present invention;

FIG. 2 is a front view of the wheel itself showing some of its throwing vanes in place, and some removed;

FIGS. 3 and 4 are detail sectional views taken of the above wheel along lines 33 and 44 respectively;

FIG. 5 is a view of one of the vanes in the above Wheel, taken from its outer end;

FIG. 6 is a view of the vane of FIGS. 1-6 taken from its inner end;

FIG. 7 is a front view of the vane of FIGS. l-6;

FIG. 8 is a view of the vane of FIGS. 1-7, looking from below;

FIG. 9 is a horizontal sectional view of a mold for casting the vanes according to the present invention;

FIG. 10 is a vertical sectional view of the mold at FIG. 9, taken along line 1tl1tl;

FIGS. 11 through 17 are views corresponding to FIGS. 2 through 8, of a modified vane construction representative of the present invention; and

FIGS. 18 through 27 illustrate various types of locking pins as well as the vane construction and runner heads used therewith.

In use, vanes for the above type of throwing wheels gradually wear way, particularly when they are used to project particles that are very hard, such as steel. The movement of the particles along the length of the vane as they are propelled causes them to abrade and erode these vane surfaces. In some very heavy usages as when sand or alumina contaminate the particles, the vanes might have to be replaced after only about twenty hours of operation or less.

Abrasion also takes place with rapid wear at the ends of the vane. At the exit end, for example, some projected particles generally ricochet back from the work pieces or surrounding members and strike the vane ends causing them to erode faster than other vane portions. In the interest of economy each vane is made of one piece cast into its final shape as closely as possible. If grinding is needed to dress the shape to the final specification, the ground surfaces seem to erode away much more rapidly than the remaining surfaces, and also seem to cause premature breakage. The grinding of the very hard material from which the vane is cast, develops fine cracks which may explain these effects.

According to the present invention, throwing wheel vanes of improved wear-resistance have a channel-shaped 3,240,632 Patented Mar. 15, 1966 body and an integral mounting flange formed along one or both side edges of the body for engagement in a mounting slot of a wheel, or a double wheel assembly (supported between two circular shaped plates), the flange having a recessed face and the recessed face having a broken-off casting gate that is confined within the recess, the vane being free of ground surfaces and the vane being free of casting gates.

The vane preferably is of abrasion-resistant heat treated alloy containing Percent C 2.5-3.5 Cr 12-26 Mo 0-6 V 04 The balance iron.

These alloys respond particularly well to heat treatment when their thickness is restricted to a maximum of inch. Thick vanes, throughout complete life tests, lost weight approximately 20% faster than thin vanes and develop deeper wear face pockets which destroy efficiency. Thick vanes weigh approximately 50% more than thin vanes which increases initial cost and imposes heavier operating stresses on support head and attachments.

The heat treatment for the thin vanes consists in heating the vanes for about one hour at about a temperature of 1750 F. followed by air quenching of the vanes.

The gate has a cross-sectional area of at least about /2 square inch. This size gate will be suitable for the casting of vanes having a body with a wall thickness of as little as about 7 of an inch even where the body is about 2 inches wide or wider. In other words, the /2 square inch gating cross-section will permit satisfactory flow of the molten metal during the casting through a sand mold having inch spacing and 2 or more inches deep. In fact, a vane body wall thickness of of an inch is best used in the form of a tapered wall with the inner end of the channel tapering down to 4 inch in thickness. Also where the vane is only mounted by a flange at one side edge instead of both sides as in a double wheel arrangement, the body may taper down to the opposite side edge, again to a wall thickness of M1. inch. Highly effective casting of such a vane is obtained with a /2 square inch gate even when the vane body has an extra heavy lip at its discharge end, and the width of the vane body is as much as 5 inches or more. The vanes have thicknesses of to inch with a floor width of A2 to 6 inches.

Where a single mounting flange is used at one edge of the vane, it is preferably made in dovetail form. If desired the vane can have mounting flanges on each of its side edges so that it can be mounted between parallel side plates in a double dovetail fashion. In this construction the mount flanges on the vanes can have any kind of a shape so long as they fit in place in whatever mounting structure the side plates provide.

Turning now to the drawings, FIG. 1 shows a throwing wheel assembly which includes a housing 20 in which is rotatably journaled a spindle 22 that carries a radially extending wheel mounting flange 24. To this flange is secured as by bolts 26, a runnerhead 28 which in turn carries a set of vanes 30. A particle supply means which can be similar to that shown in the above-identified patent, delivers blastant particles to the center of the wheel between the vanes in a space left open. The feed is controlled so that the particles are supplied to the vanes at one limited portion of the vane-rotation path, and the housing is open, as indicated at 36, to permit the particles to discharge from the vanes toward the work in the direction controlled by the particular location of the vane supply. The particular details of the spindle mounting,

housing construction, feed assembly, etc., can have different constructions. A more complete description of these details as illustrated in FIG. 1, are included in copending application Serial No. 190,725, filed April 27, 1962.

As more clearly shown in FIG. 2, the runnerhead 28 has a plurality of radially directed dovetail slots or grooves 38 in each of which an individual vane is mounted. The bolts 26 securing the runnerhead to the spindle flange 24, are shown as mounted in the floors 32 of the grooves 38.

Near the outer end of each groove the floor has a first recess 34 which is fairly shallow, and a second recess 40 which is deeper. A dam 42 just beyond the second recess is at floor level, and is cut by a channel 44 into two portions. The side walls 46 of the groove are shown as of dovetail shape except that near the outer end these walls are relieved as illustrated at 48.

The vanes are held in the grooves by gibs 49 (see FIG. 1) that have a springy tail 50 secured as by brazing to a wedge block 51 of triangular cross section. The outer end of dovetail flange on the vane has a wedge face 52 that engages a corresponding wedge face of the gib and jams the outer end of the gib against the darn 42, under the influence of the centrifugal force developed by the rotation of the wheel. Mounting of the vanes is effected by sliding a vane into its groove, and then slipping the gib in under it. The vane is arranged to move into its groove about A inch further than the illustrated wedged position, so that the block on the outer end of the gib can be inserted after the vane. After the gib is in place the vane is pulled out into wedged position, and the springy tail of the gib squeezed between the floor of the groove and the bottom of the vanes mounting flange, keeps the vane wedged. Removal of a vane is accomplished in the reverse manner. The vane is driven inwardly as by hammering, to provide the above clearance for the gib. A straight tool like a screw driver blade can then be slipped through the slot 44 to force the wedge block up over the dam 42. Both the vane and the gib are then withdrawn.

The body of the vane is more clearly shown at 54 in FIGS. 5, 6 and 7, and has a channel-shaped face 56. A bulbous enlargement 58 is provided on the back of the body at the outer end of the channel. Also this end of the body is made to extend beyond the runnerhead 28 as well as beyond the outer end of the dovetail base 43. The inner end of the channel can be beveled on its back surface, as shown at 60.

FIG. 8 shows the bottom of the dovetail base and shows a group of three positioning lands or webs 71, 72 and 73. Between them the base bottom is relieved and in the illustrated embodiment has two recesses 81 and 82. In recess 81 there is a broken-away surface 70 where the casting gate is broken off. There is no other gate used in this vane and neither the broken-away gate surface 70 nor any other part of the vane has any portion ground. The broken gate surface can be in a more recessed well 84 in the recess 81.

Land 72 or 73 helps in the removal of a vane by pushing the gib out before it. For this purpose the outer end of the gib tail is bent so as to be in the path of these lands, which are usually spaced a little from the groove floor. The tail also urges the vane flange upwardly against the sides 46 of the groove to help hold the vane accurately positioned in the runnerhead. After the wheel is used particles of abrasive and the like find their way into all available spaces and lock the vanes in place so securely that hammering is needed to remove them.

The above vanes are readily made by casting using an ordinary sand casting mold with the gating provided by a baked sand insert shaped to provide the desired base bottom configuration. The gating is preferably arranged to have a constriction adjacent the recessed surface 82 so that when the casting is completed and the solidified metal is withdrawn from the mold, the gate can be readily broken off and will then break close to that surface. Although the vane can tolerate a small amount of gate material projecting out from surface 81, a /2 square inch cross-section gate will generally break off quite close where the dovetail is fairly massive. Particularly good breaking takes place when the gate is made relatively thin, for example less than A2 inch in width, the desired area being provided by having the gate extend the necessary length along surface 81. The vanes can either be cast one at a time, or a plurality can be cast together by running their respective gates to a common pour opening or riser.

FIGS. 9 and 10 illustrate one effective casting technique that produces a plurality of vanes from each mold. A mold is here shown with two vanes 86, 87 defined by sand filling 88 with a baked core insert 90 providing gates 91, runners 92, and expansion domes 93. Pouring takes place through riser 94.

After casting is completed and the gate is broken off, nothing else need be done to place the vanes in service. In some cases, however, the surfaces of the vanes, which as cast can be very dirty and covered with sand as well as oxide, may be cleaned as by subjecting the vanes to a mild blasting treatment from a different wheel. No metal need be removed by such blasting and a tumbling type of blast operation in which a plurality of vanes are tumbled while exposed to projected streams from one or more throwing wheels, is a very effective clean-up technique. No grinding or finishing operation of any other kind need be used, and the resulting vanes show an exceedingly long life particularly where of the above composition, with very little premature eroison even though the vane bodies have a wall thickness of ym of an inch or even A1 of an inch.

Other abrasion-resistant alloys such as other chromiummolybdenum steels with high chromium content (above 5%) can also be used to make good vanes in the above manner. Moreover I to 5% tungsten can take the place of an equal amount of the chromium in the above preferred alloy.

Vanes cast from extremely abrasion-resistant material such as that referred to directly above, require a generally larger gate cross-section than other steels such as those that can be cast against chills for hardening. However, regardless of the type of alloy that is used for casting the vane, locating the gate on the recessed surface of the mounting flange enables the above important advantage in eliminating grinding.

The features of the present invention are also obtained when the gate is made in more than one portion, as by gating some metal through surface 81 and the remaining metal through surface 82, making the latter surface more extensive for this purpose.

Where the vanes are mounted between two side plates, mounting flanges or bases can be positioned at each side edge of the vane body and the gating provided on recessed portions of one or both of these side flanges. In general, side flanges when used on both sides of the vane, can be made somewhat thinner and less massive than the base 43. Also they need not be dovetail but can be of any shape and in fact can be simple extensions of the vane body.

FIGS. 11 through 18 illustrate a further vane construction in accordance with the present invention. Here, the vanes are held in a wheel 128 by plain dovetail interarrangement and locking pins 139. Adjacent one side of each groove 138 is a cylindrical pin socket 140 defining a cylindrical passageway which extends through a dovetail mounting base or flange 142 provided on each vane. A notch 144 is formed in this base or flange so that a pin 139 can be passed through the notch and seated in the socket. This pin holds the vane in place in the groove and keeps it from being thrown out by the very high centrifugal forces generated by the wheel rotation. A round notch used with a pin that is round in crosssection is admirably suited for use in wheels operating at extremely high speed. For use at lower speeds both the notch and the pin canbe angular, as for example square in cross-section. To help hold the vanes in place, as for example while waiting for the insertion of the pins, a simple arched leaf spring 150 is positioned in a recess 182 provided at the bottom of the dovetail, and engages the floor 154 of the groove.

Other vane locking means may be used such as the torsion spring loaded pair of cone points with a double dovetail arrangement shown in Patent No. 2,819,562.

The vanes 130 can otherwise be quite similar to the vanes 30, with a body portion 155 and a mounting flange 142. In addition to the bulbous enlargement 158, the channel 156, and the bevel 160, the vane 130 also has a small bevel 162 at the inner end of the channel along the edge remote from the mounting flange, to make that corner more difficult to break off in handling and the like. There are four lands, 171, 172, 173 and 174, at the bottom of dovetail flange 142, and between them three recesses 181, 182 and 183. The broken off casting gate is shown in recess 182, although it can be in either of the others or in more than one. Fewer lands and recesses can also be used, although it is desirable to have at least two so located that the mounting spring 150 can be fitted between and have its ends engaged by them.

In the constructions illustrated in the drawings, the wheel is intetnded for rotation in counterclockwise direction, as seen in FIG. 2. This is represented by the arrow 80. For rotation in the opposite direction the vanes can be made as mirror images and in the construction of FIG. 11 the pin sockets 40 would be moved to the opposite side of each dovetail groove 138. Wheels can also be provided for rotation in either direction by fitting each groove with a pair of pin sockets, one on each side of the groove. It is preferred to have the pins fit against the back surfaces of the vane bodies since in this location they are subjected to very little abrasion by the blastant particles. However, the pins can be provided adjacent the front surface of the vanes as by arranging for the pins not to project up above the face of the runner head. With such a pin arrangement a single pin socket at each dovetail groove can be used regardless of which way the wheel is rotated.

It is generally desirable to have the pins arranged so that they can be extracted as by a gripping tool. Thus, a narrowed neck can be cut around the projecting head of the pin. Where the pin head does not project, its outer face can be recessed to provide a gripping anchorage, as by drilling and threading a socket in this face.

The vanes 30 which do not use locking pins need only one type of runner head for rotation in either direction. The vanes (30 or 130) themselves need not be made reversible, but if they are so fashioned, they can be made somewhat thicker than the figure mentioned above, in order to keep the outer edges of the vanes from wear ing away too soon.

As seen in FIGS. 18 and 19 a round locking pin 139 for locking the vane to the runner head or throwing wheel has a somewhat flexible metal spring S secured thereto. The anchor end of the spring S is supported within a horizontally extending channel C drilled through the lower portion of pin 139. The remaining portion of the spring S extends axially of the pin shaft and has an outwardly extending bend therein. The axially extending portion of spring S rides in axially extending groove S in the pin shaft. When inserted in a pin socket 140 against the vane in the runner head, the wall of the socket urges the outwardly bent portion of the spring S inwardly against the pin shaft to provide a force fit whereby the vane is locked in position. With this arrangement, an additional pin locking force (in addition to the normal centrifugal force developed during operation), is provided.

A further locking pin arrangement is shown in FIGS.

20-22. Here, the pin 200 is not of a true round shape. The pin 200 is so machined that one side thereof presents a flat surface 202 along which the axially extending portion of the spring extends. The spring S has its anchor end extending through a horizontally extending channel C in the lower portion of the pin shaft as with the embodiment of FIGS. 18 and 19. In addition, however, the channel C terminates, in one form, in an elongated slot or cut-out portion 204 extending transversely of the pin axis, and the extreme anchor end of the spring S is bent over at a right angle to lie within said slot, thus locking the spring S firmly to the pin 200. Instead of the transverse cut-out portion 204, the shaft can be machined along this area to provide an inwardly extending arcuate shaped detent or face.

A somewhat different vane and pin socket arrangement in the runner head is used with the locking pins of FIGS. 20-22. As seen in FIGS. 2527, the vane 206 has a different shaped cut-out 208 for accommodating the FIGS. 20-22 pins. The cut-out 208 of the vane cooperates with the pin socket 210 of the runner head 212 (see FIGS. 23 and 24) when the vane is supported in the head to provide a pin seating socket for the pin 200 when assembled for operation. As seen better in FIG. 23, the socket 210 of the runner head 212 has a straight side lying opposite the cut-out 208 which is relieved by an outwardly extending groove 215 to accommodate the axially extending portion of the spring S.

The advantages of the present invention, that is the relatively long vane life and simplicity of manufacture, are also obtained with vanes having special configurations such as that shown in US. Patent No. 2,983,082.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

. 1. The method of making a vane without grinding for an abrasive-particle-throwing wheel comprising the steps of forming a mold which defines a shaped cavity in the form of a vane having an elongated channel-shaped body at least about 2 inches wide and not more than about /1 inch thick with an integral mounting flange along at least one elongated side edge, an exposed recessed surface at an intermediate portion of said edge, and a constricted casting gate less than /2 inch thick at said recessed surface, casting the vane by flowing molten abrasion resistant metal through said gate into said cavity, solidifying the poured metal, breaking the gating at said constriction area with said gating disposed below the surface of said one elongated side edge to provide a vane with broken gating residue confined within the recess of the recessed surface, and cleaning up the resulting vane.

2. The combination of claim 1 in which the channel is about 5 inches wide and the mold is formed with the gate in direct and open communication with an expansion dome that is entirely above it.

3. The combination of claim 1 in which the vane body is not over about inch thick throughout almost its entire extent.

4. The combination of claim 1 in which the molten metal is essentially an alloy of 2.5 to 3.5% carbon, 12 to 26% chromium, up to 6% molybdenum and up to 4% vanadium, the balance being iron, and the cast vane is removed from the mold, heat treated for about one hour at a temperature of about 1750 F., and then air quenched.

5. The method of preparing finished vanes without grinding for particle-throwing wheels, comprising the steps of forming a mold which defines a pair of vaneshaped cavities each having an elongated channel-shaped body at least about 2 inches wide and not more than about inch thick, with a thicker mounting flange along one elongated side edge and an exposed recessed surface at an intermediate portion of said edge and in said flange, said cavities having said exposed recessed surfaces facing each other and connected by gates that include a common expansion dome, each gate being constricted to a thickness of less than /2 inch and a cross-sectional area of not over /2 square inch where it opens into the recessed surface, pouring a molten abrasion-resistant metal through a riser into the dome and through the gates into the cavities, solidifying the metal in the cavities and gates, removing the solidified metal, breaking each gate away from the cast vane at the constriction to confine the gate material below the edge having the recessed surface, and cleaning up the resulting vanes.

6. The method of claim 4 wherein 1-5 tungsten replaces alike amount of chromium.

References Cited by the Examiner UNITED STATES PATENTS 11/1936 Hebert 22162 6/1960 Wells et a1. 22-130 OTHER REFERENCES Cast Metals Handbook (4th ed. 1957), published by the American Foundrymens Society, copy in Library of 10 Congress, pages 162, 163, and 235-6 relied on.

DAVID L. RECK, Primary Examiner.

Claims (1)

1. THE METHOD OF MAKING A VANE WITHOUT GRINDING FOR AN ABRASIVE-PARTICLE-THROWING WHEEL COMPRISING THE STEPS OF FORMING A MOLD WHICH DEFINES A SHAPED CAVITY IN THE FORM OF A VANE HAVING AN ELONGATED CHANNEL-SHAPED BODY AT LEAST ABOUT 2 INCHES WIDE AND NOT MORE THAN ABOUT 3/4 INCH THICK WITH AN INTEGRAL MOUNTING FLANGE ALONG AT LEAST ONE ELONGATED SIDE EDGE, AN EXPOSED RECESSED SURFACE AT AN INTERMEDIATE PORTION OD SAID EDGE, AND A CONSTRICTED CASTING GATE LESS THAN 1/2 INCH THICK AT SAID RECESSED SURFACE, CASTING THE VANE BY FLOWING MOLTEN ABRASION RESISTANT METAL THROUGH SAID GATE INTO SAID CAVITY, SOLIDIFYING THE POURED METAL, BREAKING THE GAITING AT SAID CONSTRICTION AREA WITH SAID GATING DISPOSED BELOW THE SURFACE OF SAID ONE ENLONGATED SIDE EDGE TO PROVIDE A VANE WITH BROKEN GATING RESIDUE CONFINED WITHIN THE RECESS OF THE RECESSED SURFACE, AND CLEANING UP THE RESULTING VANE.

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