US2539973A - Feeder for tumbling mills - Google Patents

Description

Jan. 3.0, 1951 r N. RANSOHOFF 2,

FEEDER FOR TUMBLING MILLS I Filed Nov. 12, 1948 3 Sheets-Sheet l N. RANSOHOFF FEEDER FOR TUMBLING MILLS Jan. 30, 1951 3 Sheets-Sheet 2 Filed Nov. 12, 1948 INVENTOR.

ATTORNEYS,

Jan. 30, 1951 v N. RANSOHOFF FEEDER FOR TUMBLING MILLS 3 Sheets-Sheet 3 Filed NOV. 12, 1948 INVENTOR.

Patented Jan. 30, 1951 UNITED STATES ATENT OFFICE FEEDER FOR TUMBLING MILLS Application November 12, 1948, Serial No. 59,596

Claims.

This invention relates to tumbling mills used industrially in the treatment of metal parts such as castings and forgings to reduce surface roughness and to remove sand, scale and dirt. Specifically, the invention constitutes an improved loading cone designed primarly for an end loading, batch type tumbling mill in which the work is treated in successive quantites for a predetermined time period and discharged from the opposite end of the mill after treatment. A machine of this character is disclosed in the patent to Nathan Ransohoif, No. 2,299,932, issued October 13, 1942, to which attention is invited.

In general, this type of mill constitutes a tumbling barrel rotatable in forward and reverse directions, and having end walls to maintain a substantial depth of castings and abrasive fragments. The barrel has a loading cone at one end including a scoop to feed work into the barrel, and a discharge cone at its opposite end having a scoop to discharge the work when the mill is operated in the opposite direction. Thus, the mill is fitated in one direction for tumbling and loading and in the opposite direction for unloading. During the tumbling operation, the work in confined in the barrel in the presence of the abrasive material such as stars, slugs and the like, so that the work pieces are exposed to a scrubbing action which reaches into the remote cavities and corners to clean thoroughly the entire surface of each piece.

The castings are completely surrounded and held in suspension by the abrasive fragments, as part of the mass, and are not likely to be damaged by collision with each other or with the moving parts of the barrel. Relatively large fragile castings safely may be subjected to this treatment withoutdamage. However, when the casting are introduced into the loading cone, there is, of course, no tumbling material in the cone to support and protect 'them. The loading cone structure in the past has been such that castings were caused to tumble about and collide with each other and with the loading cone structure, causing damage to the castings and rapid deterioration of the loading cone and its component parts.

A primary object of the invention has been to solve this problem by providing a loading cone having an improved scoop structure combined with a deflector, which elements cooperate to skid the casting gently into the barrel from the loading cone. Also, the deflector is arranged so as to pass under the castings if the scoop is full and thereby prevent the castings from beingengaged and tumbled by the scoop.

Briefly, the improved loading mechanism constitutes a pick-up scoop mounted in the cone, the scoop having the form of a V with a work pick-up opening at its flared end and a charging regulates the number of castings entering the scoop in each cycle of rotation so that if the scoop is full the castings roll over the deflector without damaging impact, to be picked up on successive cycles. It is inherent in the structure that the larger castings more readily will roll over the deflector than the smaller ones, therefore, there is automatic compensation in favor of the larger more fragile pieces.

It frequently happens that castings are thrown from the tumbling barrel back into the loading cone when the direction of rotation is reversed for discharge. To avoid this difficulty, it has been a further object to provide a scoop structure which is nearly symmetrical in design and which, in combination with the deflector, is operative in either direction so that disgorged castings are returned automatically to the tumbling barrel.

Further objects and advantages of the invention will be more fully disclosed in the specification with reference to the drawings so that those skilled in the art readily will comprehend the various modifications to which the invention is subject.

In the drawings:

Figure 1 is a general side elevation of a tumbling mill incorporating the improved loading cone structure.

Figure 2 is an enlarged sectional view taken on line 2Z, Figure 1, illustrating the arrangement of the scoop and deflector in the loadin cone.

Figure 3 is a fragmentary side view of the loading cone with a portion of the cone removed to illustrate the relative disposition of the "deflector and scoop.

Figure 4 is an enlarged fragmentary sectional View taken on line t-4, Figure 2, detailing the attachment means for t the scoop.

Figures to 12 inclusive are diagrammatic views illustrating the Various positions during one rotation of the loading cone and the operation of the deflector and scoop member with reference to the work pieces in the cone.

As shown in Figure 1, the mill assembly in general constitutes a tumbling barrel l5 mounted within a frame, indicated generally at It, including a vertical mounting structure I! for the speed reducer I8. The tumbling barrel is supported by means of rollers is tracked upon bearing rings 20 secured to the barrel, the rollers being journalled upon brackets 21 secured to the base structure 22, as part of the frame. The mill is driven by means of a sprocket chain 23 passing over a large ring sprocket 24 secured to the tumbling barrel and driven by a small sprocket 25 keyed upon the drive shaft of the speed reducer H3. The speed reducer includes a sheave 26 which is driven by an electric motor (not shown).

The tumbling mill consists essentially of three main parts; the tumbling barrel E5 in which the mass of work and abrasives is agitated, the loading cone 28 secured to one end of the barrel and the discharge come 35 secured to the opposite end. These three sections are joined together and rotate as a unit. As disclosed in the Ransohoif patent above noted, the machine is automatic in operation and is controlled by driving the assembly either in a tumbling direction, in which case the chargingcone is operative to charge the work he detachable section of pieces into the tumbling barrel, or by rotating it in the opposite direction which causes the work pieces to be discharged from the tumbling barrel into the discharge cone 35. The discharge cone includes a separator and star return apparatus (not shown) also operable in the tumbling direction. When the machine is operated in the tumbling direction, the loading cone scoop is operable to pick up work pieces and transfer them from the cone to the tumbling barrel and the star return apparatus is operable to pick up the stars from the discharge cone to charge them into the tumbling barrel. along with. the work. The machine operates most efiiciently with a substantial depth of work and tumbling material in the barrel so that the work pieces wallow in a mass of abrasive fragments substantially in suspension.

Described in detail, the loading cone 28 comprises a cone shaped cylinder 3| having an inner end wall 32 at its large end which is provided with a triangular opening 33 for passing the work into the tumbling barrel. The loading cone is secured to the end wall 34 of the tumbling barrel either by means of welding or by bolts and the end wall 34 includes an opening 35 in registry with opening 33. The opposite or small end of the loading cone is provided with an outer end wall 36 which includes an opening 31 through which the work pieces are charged. In operation, the work may be introduced into the loading cone either by hand or by means of a loading chute extending into the opening 31, depending upon the type of installation. By virtue of the conical shape of the loading cone and its rotation, the work pieces slide inwardly toward the end wall 32 and must be elevated up to the opening 33 for passage into the tumbling barrel. To perform this function, the loading cone includes a loader scoop, indicated generally at 39, operating in conjunction with .a deflector unit 40.. The scoop may be described generally as a pocket fabricated from sheet steel plates which extend at an angle between the end wall 32 and the adjacent wall of the loading cone as viewed from the side (see Figure 1). As viewed from the end as in Figure 2, the loader scoop is of V shape, having plate sections d! and 42 angularly related to each other and to the end wall and forming generally a pyramid shaped receptacle.

Described in greater detail, each of the sections 4! and 42 is secured to the inner surface of the cone preferably by welding along the lines 43 and to the face of the end wall 32 by welding along the lines 44. To permit access into the tumbling barrel, the scoop includes a detachable V-shaped plate which forms a continuation of the respective sections 4| and 42, extending to an apex. The plate 45 seats against the end wall 32 along the line 46 as a continuation of the weld lines 44 of plates 4| and 42. A triangular work pick-up opening indicated at 4'! (Figure 2) is formed at the forward end of the receptacle for passing work from the cone to the charging opening 33. It is to be noted that the charging opening 33 is triangular shaped, conforming to the shape of the plate 45. Plate 45 is secured to the respective plate sections 4! and 42 and to the end plate 32 by means of a series of stu s 43 secured along the edges of the plates 4| and 42 by welding (see Figure 4). The marginal edges of plate 45 overlie the edges of plates 4| and 42 with the studs is passing through apertures formed in the opposite edges of plate 45. Nuts 49 are screwthreaded upon the studs 48 to secure the plate in position. The edges 50 of plate 45 are joined to the end wall 52 by means of mounting strips 5| welded adjacent the opening 33 to provide a flange. This flange also is provided with a series of studs 48 secured by welding to the flange and provided with nuts 49 to secure the plate 45 thereto. When it is desirable or necessary to enter the tumbling barrel for service or repairs, the plate 45 may be detached conveniently by removing the nuts 49. In operation, the plate section 42 forms the loader arm and plate 44 forms the retriever arm as hereinafter disclosed.

The deflector unit 40 generally is of triangular shape as viewed in Figure 3. It is fabricated from steel sheet stock having side walls 52 and 53 and a top plate 54. In its preferred construction the side plate 53 and top plate 54 are formed from a single blank bent along the line 55 to define the side wall 53 which forms the leading edge of the unit. The plate 52 is joined to top plate 54 by welding along the line 56, and the unit is secured to the outside end wall 36 along the line 57 also by welding. It is to be noted that the side wall 53 which forms the leading edge of the deflector unit is disposed at an angle of approximately 45 with respect to the top plate 53 to permit the work to roll over the deflector. The leading edge 53 of the deflector in combination with the loader arm 4|, delineates a passageway leading to the pick-up opening 41. The longitudinal angulation of the leading edge with respect to the axis of the cone causes the work pieces to be urged into the opening 4'! when the mill is rotating in the tumbling direction.

Referring to Figures 5 to 12 inclusive, the operation of the loading cone with particular reference to the scoop and deflector units is illustrated diagrammatically. As shown in Figures 5 and 6, the work pieces or castings, indicated at A, B, and C, are illustrated in the position they assume after they have been introduced into the loading cone. As the cone rotates, the castings will remain in the lower area of the cone and will slide inwardly toward the inner wall 32. As the pick-up opening i? approaches, the castings are contacted by the angularly disposed plate 42 of the scoop which urges them forwardly into position to be contacted by the leading edge 53 of the deflector unit which occupies a position adjacent the opening 47, causing the castings to be deflected into the opening to be picked up by the scoop. Since the capacity of the scoop is limited, those castings which cannot enter, merely ride over the deflector unit instead of being picked up and elevated by the scoop, in which case they would be dropped as the scoop approaches its upper position, causing damage to the casting as well as to the loading cone assembly. This condition is illustrated most clearly in Figures '7 and 8 in which the deflector is passing under the work piece C.

As the scoop approaches its vertical position, as illustrated in Figures 9 and 10, the work pieces, by virtue of the shape of the scoop proper, gravitate toward the opening 33 for discharge into the tumbling barrel. In operation, the work pieces may be'fed into the loading cone until the mass of work and abrasive fragments attains a level slightly below the opening 33 and at this level the tumbling operation is continued for the required treating period. After the treatment is completed, the mill rotation is reversed so as to 1' render the discharge pick-up chute at the opposite end of the barrel effective to discharge the work from the tumbling barrel. In the discharge chute 38, the abrasive fragments and work pieces are separated, the work pieces are t discharged from the open end of the discharge cone and the abrasives are retained in the cone. During this operation, of course, the loading cone is ineffective to pick up additional work pieces, but in case any of the pieces are thrown from the barrel into the pick-up scoop they are charged back into the tumbling barrel.

It has been found in operation that the scoop structure, in combination with the deflector, handles the castings in a more gentle manner and permits the handling of larger and more fragile castings than has been possible heretofore. The pick-up scoop in and of itself is not positive in operation but depends upon the action of the deflector to deflect the work pieces in position for pick up and permits the pieces to roll gently over the deflector when the scoop is filled to capacity. This prevents excess castings from being picked up and dropped by the scoop.

Having described my invention, I claim:

1. A loading cone for a tumbling mill having a rotatable tumbling barrel comprising; a drum secured to an end of the rotatable tumbling barrel, said drum having a wall at its inner end, a work pick-up scoop within said drum angularly related to the end wall, said scoop having the form of a V having a work pick-up opening at its large end and a discharge opening at its apex communicating with the tumbling barrel, and a triangular deflector body residing within the drum adjacent said work pick-up opening and arranged to deflect the work pieces into the pickup opening.

2. A loading cone for a tumbling mill having a rotatable tumbling barrel comprising; a drum secured to an end of the rotatable tumbling barrel, said drum having a wall at its inner end, a work pick-up scoop angularly related to the end wall, said scoop having the form of a V having a work pick-up opening at its large end and a discharge opening at its apex communicating with the tumbling barrel, and a deflector unit secured to the inside diameter of the loading cone adjacent said work pick-up opening, the said deflector unit having side faces which converge toward the work pick-up opening arranged to deflect the work pieces from the drum into said pick-up opening.

3. In a tumbling mill having a rotatable tumbling barrel, a work loading drum secured to the end of the tumbling barrel, the drum having an end wall dividing the same from said tumbling barrel, a scoop mounted on said end wall having a work pick-up opening at one end adapted to receive work pieces and to elevate the pieces during rotation of the drum, said end. wall having an opening communicating with the scoop to charge the work pieces into the tumbling barrel, and a deflector within said drum adjacent said pick-up opening, the leading edge of said deflector being inclined at an angle receding from the direction of rotation to cause the deflector to pass under the work pieces when the scoop is charged.

4. In a tumbling mill having a rotatable tumbling barrel, a work loading cone secured to the end of the tumbling barrel, the cone having an end wall dividing the same from said tumbling barrel, a scoop mounted on said end wall having a work pick-up opening at one end adapted to receive work pieces and to elevate the pieces during rotation of the cone, said end wail having an opening communicating with the scoop to charge the work pieces into the tumbling barrel, and a deflector within said drum adjacent said opening, said deflector having its leading edge angularly related to the longitudinal axis of the loading drum to engage and urge the pieces toward said work receiving opening, the leading edge of said deflector being inclined at an angle reced-- ing in the direction of rotation to cause the deflector to pass under the work pieces when the scoop is charged.

5. A loading device for a tumbling mill having a rotatable tumbiing barrel comprising; a drum having opposite end walls, said drum being secured upon the end of the tumbling barrel, the outer of said end walls having an opening for the introduction of work pieces into the drum and the inner wall having a work feed opening communicating with the interior of the tumbling barrel, a pick-up scoop secured to the inner wall adjacent said feed opening, said pick-up scoop constituting a pair of limbs angularly related to each other and extending at an angle between the end wall and the drum and having a work pick-up opening adjacent the drum, and a deflector mounted adjacent said pick-up opening, said deflector constituting a triangular unit having its converging end extended toward said pick-up opening to deflect the work pieces into said opening by rotation of the drum.

6. A loading device for a tumbling mill having a rotatable tumbling barrel comprising; a drum having opposite end walls, said drum being secured upon the end of the tumbling barrel, the outer of said end walls having an opening for the introduction of work pieces into the drum and the inner wall having a work feed opening communicating with the interior of the tumbling barrel, a pick-up scoop secured to the inner wall adjacent said feed opening, said pick-up scoop constituting a pyramid shaped receptacle extending fromsaid opening in an inclined plane to the drum and having a work pick-up opening adjacent the drum and having a removable section for access into the tumbling mill, and a de' fiector body mounted in the drum adjacent said pick-up opening having side faces converging toward the work pick-up opening arranged to divert work pieces from the drum into said open- 7. A loading device for a tumbling mill having a rotatable tumbling barrel comprising; a drum having opposite end walls, said drum being secured upon the end of the tumbling barrel, the outer of said end walls having an opening for the introduction of work pieces into the drum and the inner wall having a work feed opening communicating with the interior of the tumbling barrel, a pick-up scoop secured to the inner wall adjacent said feed opening, said pick-up scoop constituting a pair of plate sections angularly related to each other and extending at an angle between the end wall and the drum and having a work pick-up opening adjacent the drum, a removable V-shaped plate secured to said plate sections opposite the work feed opening for access into the tumbling barrel, and a deflector mounted adjacent said pick-up opening to deflect the work pieces into said opening by rotation of the drum.

8. A loading device for a tumbling mill having a rotatable tumbling barrel comprising; a drum having opposite end walls, said drum being se cured upon the end of the tumbling barrel, the outer of said end walls having an opening for the introduction of work pieces into the drum and the inner wall having a work feed opening communicating with the interior of the tumbling barrel, a pick-up scoop secured to the inner wall adjacent said feed opening, said pick-up scoop constituting a receptacle extending from said opening in an inclined plane to the drum and having a work pick-up opening adjacent the drum, and a deflector mounted in the drum adjacent said pick-up opening, said deflector constituting a top wall spaced above the inner surface of the drum by a pair of side walls angularly related to each other extending from the outer end wall of the drum and converging toward the pick-up opening and adapted to deflect work pieces from the drum to the pick-up opening by rotation of the drum.

9. A tumbling barrel having a loading cone at one end thereof, the loading cone having a forward end wall and a rearward end wall, the rearward end wall having an opening in communication with the tumbling barrel, a scoop in conjunction with said opening, and a deflector arranged upon the forward end wall of the loading cone, the deflector constituting a body having a side face which converges toward the scoop and a top face spaced above the surface of the cone, the side face and scoop being arranged cooperatively to direct a casting from the loading cone in skidding movement to the scoop and through the scoop into the tumbling barrel, the top face providing a passage surface for excess castings such that the castings during rotation of the unit do not tumble and fall upon one another but skid over the passage surface.

10. A tumbling barrel having a loading cone at one end thereof, the loading cone having a forward end wall and a rearward end wall, the rearward end wall having an opening in communication with the tumbling barrel, a scoop mounted on the rearward wall and communicating with said opening, and a deflector arranged upon the forward end wall of the loading cone, the deflector extending toward the scoop at an angle to the axis of the cone to direct a casting from the loading cone in skidding movement to the scoop and through the scoop into the tumbling barrel and having a top face spaced above the surface of the cone constituting a passage surface such that excess castings during rotation of the unit do not tumble and fall upon one another but skid over the passage surface.

NATHAN RANSOI-IOFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,615,622 Greene Jan. 25, 1927 2,299,032 Ransohoif Oct. 13, 1942

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