US2412040A - Rotating table casting apparatus - Google Patents

Description

Dec. 3, 1946. c. GALL EIAL ROTATING TABLE CASTING APPARATUS Filed June 23, 1942 2 Sheet S-Sheet 1 'INVENTORS ('arl (fall y flan/f I Bwrfia q-unmmm aria/m5) Patented Dec. 3, 1946 2,412,040 ROTATING TABLE GASTiNG Armm'rcs Carl Gall and Frank J. Prucha, Omaha, Neb'r assignors to American Company, New York,

New Jersey Smelting and Refining N. Y-., a corporation of Application June 23, 1942, Serial No. 448,054

Claims.

This invention relates to casting apparatus and more particularly to a machine for casting metal slugs as, for example, lead slugs.

According to a preferred manner of practicing the invention, the apparatus comprises a turntable' rotatable about a vertical axis and having a series of molds disposed along the edge of the turntable. A series of stations surrounds the turntable at which, as the turntable rotates, the various operations are performed on the molds. The molds comprise an inner mold space and an outer jacket space to which water-supply conduits are connected. A water-supply tank rotates with the turntable and controls the water supply to the several water-supply conduits as the turntable revolves. The several IIlOldS are mounted in such manner that as the turntable revolves, they are tipped from upright to sub stantially inverted position to discharge the cast billets and back again to upright position to receive molten metal.

According to the preferred embodiment of the invention, the cooling water is applied to the jacket and the freezing of the molten metal is controlled'in such a way that the metal freezes from the bottom up, thereby preventing formation of internal cavities and draw holes due to shrinkage. The mold. is filled with molten metal while the water jacket is empty, after which the water jacket is gradually filled. After filling with molten metal, the molds move under stationary gas burners which apply heat to the top of the molds thus delaying freezing of the tops of the molds until last. The turntable continues to rotate and the molds continue to travel to a point approaching the starting position where the molds are tipped to drain the water and then to dump the slugs from the mold, after which the machine rights the mold as it approaches the starting point where it is again filled with molten metal for the next cycle of operation.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

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 referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which Fig. '1 is a plan view of the machine with part broken away to give room for making the draw ing on a larger scale;

Fig. 2 is a vertical section on e Fig. 3 is a vertical section through an individual mold taken on the line 33 of Fig. 1; and

Fig. 4 is a transverse section through the mold taken on the line #4 of Fig. 3.

Like reference characters denote like parts in the several figures of the drawings.

In the following description and in the claims, various details will be identified by specific names for convenience, but they are intended to be as generic in their application as the art will permit.

Referring now to the drawings, the turntable 9 is shown mounted upon a foundation to which may be of usual concrete construction. Resting upon the foundation is a discharge basin l3 and a plurality of annularly arranged supports l2 upon which rests an annular catch pan l I for the purpose of catching overflow from the water jackets of the molds 60. Water flows from catch pan I i into discharge basin I3 to which drain pipe [4 is connected. The foundation also supports a dis charge chute for receiving the cast slugs 86 at the discharge station as will hereinafter more fully appear.

Resting upon the foundation [0 is a hollow base l5 having suitable anchors l6 embedded in the concrete foundation [0.- Bolted to the base I5 is a casing l'l having a lower section l8 and an upper section l9 suitably bolted together. The lower section 18 has an annular seat for an axial thrust bearing 23. Journalled at 20 in the lower section it! is the mast- 25 having keyed thereto a worm wheel 2| engaging thrust bearing 23. Worm wheel 2| has a hub 24 journalled in upper section l9.

At the top of the machine is an overhead struc ture indicated by 21 which may be secured to the beams of the ceiling of the room in which the casting machine is housed. Secured to the overhead structure 21 is a bearing 26 in which the upper end of mast 25 is rotatably mounted. Sui-t ably journalled in casing H is a worm 28 which meshes with and drives worm wheel 2|. Worm 28 is suitably driven by belt or chain 30 from a speed reducer 29 which may be driven by any suitable source of power such as an electric moto'r, not shown.

The platform of the turntable 9 comprises a hub plate 33 secured to hub 24 to which are secured a series of radial beams 34 arranged in pairs. These teams 34 are bent at their outer ends to define parallelpaths and the adjoin the line 2-2 of ing beams of each pair are connected together throughout their lengths in any suitable way and at their spaced ends by connecting pieces or plates 31. The radial beams 34 of each pair near their inner ends are connected by structural pieces 3|. The parallel ends of the beams 34 support the individual molds 60 ina manner hereinafter "described more in detail. The outer edge of the platform 9 is supported by a plurality of hang rods 35. These hang rods, one for each connection piece 31, pass through their respective connecting pieces3'l and through the mast collar 38. The ends of the hang rods have suitable washers and nuts: for ,impartingthe hanging stress to the connecting pieces 31and to the mast collar 36 and for adjusting purposes.

Secured to the casing I! is a trough-shape cam track 38 in which is mounted a plurality of" rollers 39 mounted upon levers 48 pivoted to the connecting pieces 3| by pivots 32. There is one lever. -40 for each mold. Thecam path ,38 has an irregular shape as indicated particularly in Fig. l for the purpose of controlling the position of the molds with respect to the platform of; the turntable as will be explained hereinafter. For supplying water to the several; molds, a waterhead tank 43 is secured toythe mastg by suitable supportingdevices indicated. by. The tank 43 has a stationary supply pipe 44 having a valve 46 controlled. by afloat 45. .This maintains the levelof the water in tank 43 at apredetermined point as will be understood by. those skilled in the art. 3

,The tank 43 has a plurality of outlet pipes 48, one for eachmold. These outlet pipes 48 may have .hand valves 52 whereby the water may be regulated. :or'shut off for emergency or repair purposes. Ordinarily the valves 52 are open. Connected to each pipe 48 is afiexible hose H connected to the water jacket of the mold. 60. a For. controlling water supply through the several pipes 48, eachpipe is provided with a valve 49 controlled by a lever 50 having a roller. 56. These levers 5B are'normally resiliently held in outer position by a series of springs 5| secured to a ring 41 suitably supported bythe tank 43. The position of the levers 50 is determined by a stationary cam path 54, having the shape illustrated particularly in Fig. 1, suitably secured to the upper structure 21 by members 55. The water valves 49 are open when the levers 50 are in their outer position but, as the turntable revolves, the rollers 58 engage the cam track 54 to shut off the water supply to the several molds as they approacnthe dumping and pouring positions in their cycle of rotation. I

Referring now-to Figs. 3 and 4, the mold itself, indicated by 60, may be of suitablesheet or plate metal parts suitably welded together, as indicated. The mold comprises an inner shell 6| having a bottom wall 63-forming a mold space 62. An intermediate wall 65 is' connected to bottom wall 53. The top wall 61 is connected to walls 6| and B5 and hassecured thereto an outer wall 64. Walls 6| and 65form a water jacket space filiwhich is supplied by inlet fitting 18 secured to the flexible supply pipe H. v'I'he water. jacketxBS has anoverflow opening 12.,cut in the wall 65, which communicates with the overflow space between walls 64 and 65. Secured to the inner shell BI is a massive heatretaining ring 68, preferably of a good heat-conducting, heat-holding material suchas copper Disposed between the ring 68 and the water jacket is a heat insulating gasket 63 of good heat insue weight of the molds. H racks 19 on the ends of beams 34, the sides of 82 secured together in a suitable manner.

lating and temperature withstanding material such as asbestos.

The several molds 60 are mounted upon the turntable 9 in the following manner. Each mold has secured thereto studs 15 forming trunnions. These trunnions are secured at a point above the center of gravity of the mold so that the mold tends normally to take an upright position. Secured to the trunnions are rollers or wheels 16 and gears 11. The rollers 16 roll on the parallel tracks 18 on the ends of beams 34 and take the The pinions TI engage the the racks I9 acting as side guide-ways for the rollers 16 to keep them in their paths.

Pivoted to the ends of the trunnions 15 are links which converge to form parallel ends Pivot connection 8| connects ends 82 and the lever 40. Thus, it will be seen that, as the turntable 9 rotates, the stationary cam path 38, actingupon roller followers 39, exerts a pull on-thetrunnions 15 which moves the trunnions radially of the turntable causing the wheels .16 to, roll upon their fiat straight paths 18. The pull of links 80 not only imparts a translational movementto the mold but, due to the rack-and pinions lj, 19, also imparts a rotary movement to the molds, causing them to move from upright position -as shown, for example, at the left of Fig. 2, to dumping position, as shown at the right of Fig. 2. 7

At certain points along the periphery oi the turntable stationary gas burners 83 are provided. In the present case, these burners are suspended from a suitable stationary supply pipe 84 suitably supported adjacent the turntable and are for the purpose of applying heatto the tops oi the molds and their contents of molten metal for the purpose hereinafter described m'orein detail.

For convenience, the various positions which each mold 60 may take as the turntable 3 rotates are indicated by the letters A to J which are'called stations. It is preferable that the turntablerotate step by step, intermittently, a distance equal the distance between two adjourning stations; The molds are all identical and the motor drive maybe controlled manually to give tl'ies'tep-by step movement, or suitable 'automatic'control, not shown, may be provided fOr'thlS purpose. v

The position A is the pouring position. The mold '60 is upright at this point and will be sultably filled with molten 'metal froma pouring spout or ladle, not shown, The discharge position is'indicated'by H. The turntable rotates'ln the direction indicated by the arrow X. It will be noted that the cam path 38 is so shaped that the molds are'upright at most of the stations and thus-the molds begin to tip as they leave station F, being substantially horizontal at station 'G' and totally tipped to inclined position'at discharge station I-I,*again substantially horizontal at'station I and entirely upright at station J. Y It will also be noted that the cam path: 54 is so shaped that water is being supplied to the molds for overhalf of the entire rotary cycle' of the'turntable. The water'begins to be turned oil. at station D and is all .the way on at station F. The wateris kept turned off through stations G, H, LJ and A and is turned on as the molds leave station A, being full on at all stations B and C. The'sequence of events in a complete cycle is as follows. This will .be given for one mold, ltbein understood that identical treatment is accorded all of the molds: j no. '1

,The upright mold will be fllled with..molten 'metal such as lead atstation A with its water jacket empty, having been previously emptied from the previous cycle. As the mold leaves station A, lever 50 rides off theend of cam 54 opening water valve 49 causing the water to flowand begin to fill the water jacket. The mold then passes under the first gas burner 83 at station B. The water jacket continues to fill at a rate determined by the rate at which water is supplied. 'I'he'relative rate of supplying cooling water and the speed imparted to .the tumtable determines thestation at which the water jacket becomes completely filled with water. The rate of water flow may be regulated by hand valves 52. Since the mold continues to be heated by the four gas burners 83 at the four stations B, and since it is desired to utilize the heat retaining ring 68 to keep the top of the mold hot, it is preferred that the water jacket not become completely filled until it reaches some station of the C group, preferably the first station of .the C group.

As the mold passes from the last station B to the first of the eight positions C, it leaves the gas burners and continues to be cooled by water circulated through the Water jacket 66, the water overflowing through outlet 12, running down through annular space between sleeves 64 and 65, discharging into the catch pan II. The molten metal becomes completely solidified at station D or E. At position D, the water-control lever 50 engages the flared end of cam 54 and gradually closes the Water valve 49 through station E until at station F the water valve is completely closed. As the mold advances from station F, the cam path 38 causes the mold to start to tip to horizontal position, as shown at position G, where the water drains from the jacket into the catch pan l3; the mold continues to tip until it reaches discharge station H, where it is completely tipped, and discharges the solidified slug, indicated by 86 in Fig. 2, into the discharge chute 85. After discharging the slug, the mold is tipped back to horizontal position at station I and thence to vertical upright position at station J, ready to be filled again as it approaches the mold filling position A.

Thus, a method of casting is provided which controls the cooling of the molten metal in the mold so that the metal is cooled from the bottom up. The retardation of the supply of cooling water to the top of the mold, the use of external heat by the gas burners, the use of the massive heat-retaining rings, all insure keeping the metal at the top of the mold molten so that this top metal is the last to freeze. Thus, external cold shots, internal cavities, draw holes due to shrinkage, etc., are prevented. The fact that the water jacket is empty at the time of pouring and is gradually filled up with water, allows the metal to chill from the bottom up. This permits the molten surface of the metal to settle down evenly while cooling and prevents cavities and draw downs. Thus, a perfect slug is produced free of external cold shots, internal flaws and draw downs and is flat on the top.

The machine is simple in construction and operation. It puts each mold through a predetermined, mechanically controlled cycle insuring equal treatment to each mold. This insures carrying out the above described process of pouring, cooling and dumping in proper predetermined sequence and giving proper treatment at each step. It will be understood that the details and dimensions may be varied by those skilled in the art. In the form shown the internal mold cavities may be of such size as to produce metal slugs of approximately five inches in diameter and13 inches in length.- The diameter ofthe turntable may be about ten feet and may hold twenty molds. The machine is especially .adapted to casting lead slugs of refined lead, antimon'ial lead, lead allo-yed'with tin, etc; In: fact, its-use is most adaptable to all low melting point metals. While certain novel features of the invention have been disclosed and are pointed out in-the annexed claims, it will be understood that vari-' ous omissions, substitutions and changes may be made by those skilled in the art without departing from the spirit'of the invention. I

What is claimed is: 1

1. A casting machine comprising a turntable, means for mounting said turntable to revolve about a verticalaxis, a plurality of oyllndrical molds disposed around the margin of--'saidturntable, supporting devices for said molds, each supporting device comprising spaced racks on said turntable, rollways alongside said racks, stud shafts secured to said mold, pinions secured to said stud shafts and meshing with said racks, wheels secured to said stud shafts and disposed on said rollways, links pivoted to said stud shafts, a lever pivoted to said turntable and connected to said links, a stationary camway, a follower on said lever disposed in said camway, whereby as said turntable revolves, said camway rotates said pinions on said racks to rotate the molds from upright to substantially inverted positions.

2. A casting machine comprising a carrier, means for moving said carrier, a plurality of molds disposed on said carrier, supporting devices for said molds, each supporting device comprising spaced racks, rollways alongside said racks, stud shafts secured to said mold, pinions secured to said stud shafts and meshing with said racks, wheels secured to said stud shafts and disposed on said rollways, a stationary camway, a follower connected to said stud shafts and disposed in said camway, whereby as said carrier moves, said camway rotates said pinions on said racks to rotate the molds from one position to another. I

3. In a casting machine, a foundation, a base secured to said foundation, a bearing secured to said base, an overhead structure having a bearing, a turntable comprising a mast journalled in said bearing, a mast support secured to said mast, means for driving said mast, a platform secured to said mast, hang rods connecting said mast support and the outer margin of said platform, a plurality of molds supported on the outer margin of said platform, a water tank supported by said turntable, conduits connecting said water tank and said molds, each conduit having a valve and a control lever, a stationary camway guiding said control levers to admit water to and shut water off from said molds, second control levers, connections between said second levers and said molds, and a second camway guiding said second levers to vary the positions of said molds as the turntable revolves.

4. In a casting machine, a foundation, a base secured to said foundation, a bearing secured to said base, a mast journalled in said bearing, a collar secured to said mast, an overhead structure having a bearing supporting said mast, a worm wheel having a hub secured to said mast, a worm meshing said worm wheel, means for driving said worm, a turntable comprising a plate secured to said hub, pairs of spaced, substantially radial beams secured to said plate, con- V molds-supported along the outer margin of said turntable; a water rtank supported by said mast,

conduits connecting, said water tank and said molds; each conduit having a valve and a control lever, a;stationary camway guiding said control levers to admit water to andshut water oil? from said molds, a second camway secured to said base under said platform, second control levers guided by said second camway, and connections between said second levers and said molds to change the positions of said molds as the turntable revolves.

5. In apparatus for casting metal, a turntable, means for mounting said turntable to revolve about a vertical axis, a plurality of open-top moldsppivotally mounted around the circumference of said turntable, each mold comprising a mold space and a water Jacket surrounding-said mold space, a heat-retaining mass connected to said mold at the top, a heat insulator between said heat-retaining mass and said'water jacket.

a plurality of fixed stations disposed about said turntable, one of. said stations constituting a pouring station and another constituting a dumping station,.burners at certain of said sta-" tions for heating said heat-retaining mass, conrtrol means for feeding water to said jackets at certain stations and stopping fiowpof water at other stations, and control means for moving said molds to upright position for the pouring station and the heating stations and for tilting said molds for the dumping station, whereby controlled cooling 01' the molten metal is obtained.

CARL GALL. v FRANK J. PRUCH A.

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