US3191249A - Casting apparatus - Google Patents

Description

June 29, 1965 ARNOLD ETAL 3,191,249

CASTING APPARATUS Filed Feb. 12, 1962 2 Sheets-Sheet 1 FIGJ FIG.4

I I INVENTOR. PAUL L. AKA/OLD J 1 BY Mum/vi AI. Mou rwmszs ATTORNEY June 29, 1965 P. L. ARNOLD ETAL 3,191,249

CASTING APPARATUS 2 Sheets-Sheet 2' Filed Feb. 12, 1962 I43 IP (w FIG-2 FIG.3

INVENTOR. PAUL L. ARA/5L0 y WILLIAM A MaMTc-oMEIH A TTORNEY United States Patent Ofiice 3,191,249 Patented June 29, 1965 Jersey Filed Feb. 12, 1962, Ser. No. 172,663 1 Claim. (Cl. 22-82) In the manufacture of cast iron pressure pipe the metal is melted in a cupola or other suitable furnace, collected in a forehearth and transferred by ladle from the forehearth to the casting pit as needed. The foundry invariably has several casting machines in operation, each operating at its own independent rate according to the product being cast, the abilities of the operating crew and other factors such as functioning efficiency of the equipment. In order to assure that metal is available at the casting machine, so that no slow down in casting rate will result, it is generally the practice to use a transfer ladle which has a capacity several times greater than that of the machine ladle so that the transfer ladle may be set in position at the machine ladle and can provide metal for several pipes before it is necessary to bring more metal front-the furnace. In the meantime the overhead crane, or other means used, is free to deliver metal to the remaining machines. Obviously, the capacity of the trans fer ladle must be limited to a practical size. Because of rapid metal cooling only a very limited number of casts can be madefrom an unheated transfer ladle. In the centrifugal casting of pipe in metal molds such as in the de Lavaud process, the metal temperature is particularly critical and must be kept within a very narrow range.

In practice, the proper amount of metal is poured from the transfer ladle to the machine ladle. The transfer ladle stands idly in position until the casting machine goes through the part of its cycle wherein the molten metal is delivered to the mold. At this time, the machine ladle is again filled from the transfer ladle and this procedure is repeated continuously. It is imperative, if the casting rate is to be maintained high, that the transfer ladle be refilled or a filled ladle be substituted therefor during the period of time in a casting cycle when the transfer ladle is standing idly by. If this is not accomplished during the allotted time, the casting machine must be stopped until a supply of hot metal is available.

It can readily be seen that when several machines are in use, the'call for metal from the forehearth, or cupola, from several machines may be simultaneous or so close together that it is impossible for the overhead crane to deliver molten metal to all the machines at the exact time it is needed.

As casting rates increase due to technological improvements and advances, the demand for molten metal at the machine increases proportionally while the time to accomplish this delivery decreases proportionally so that it becomes even more difficult to keep a ready supply of molten metal at the machine.

Accordingly, this invention has for its object the provision of an apparatus which greatly simplifies the problem of delivery of molten metal to the casting machine.

More specifically, the object of this invention is the provision of a transfer ladle car which permits the rapid substitution of one transfer ladle for another transfer ladle at the machine ladle.

A further object is the provision of an apparatus which permits the overhead crane operator to more evenly space the deliveries of hot metal from the forehearth or cupola to the various casting machines.

Other objects and advantages will be seen from the following description and the drawings in which:

FIGURE 1 is a side elevation view of a de Lavaud pipe casting machine utilizing the apparatus of this invention.

FIGURE 2 is a front elevation and FIGURE 3 is a top elevation of the ladle transfer car which is the specific object of this invention.

FIGURE 4 is a schematic diagram of the hydraulic piping which provides for alternate activation and inactivation of the two ladle cradles mounted on the transfer ladle car.

Referring to FIGURE l, the casting machine comprises a mold 1 rotatably mounted in a water box 2. The motor for turning the mold is designated 3. The water box is mounted on wheels 4 and may be moved up and down inclined track 5 by means of a hydraulic cylinder,

not shown. A casting trough 6 is mounted at the uphill end of the inclined track 5 and is positioned so as to enter the mold when the water box is moved up the incline. Adjacent the end of the casting trough there is mounted machine ladle 7 which is of the type that gives a constant discharge when tilted at a uniform rate.

Adjacent the machine ladle 7 there is provided a transfer ladle car 8 which can be shifted laterally of the casting machine along tracks 9. In FIGURES 2 and 3 it can be seen that this car supports two ladle cradles 11 and 12. Cradle 11 is tiltably mounted between vertical columns 13 and 14 by means of trunnions 16 and cradle 12 is tiltably mounted between vertical columns 14 and 15 by means of trunnions 17.

Hydraulic cylinder 18 is pivotably mounted to car 8 by means of pin 19 and piston rod 20 is pivotably mounted to lever arm 21 which projects from cradle 11. As hydraulic fluid is forced into the cylinder 18, the piston rod is forced upward and in so doing cradle 11 is rotated about trunnions 16. As a result, transfer ladle 22 can be tilted to discharge its contents through spout 23 into machine ladle 7. In a similar manner hydraulic cylinder 24 is connected to car 8 by pin 25 and piston rod 26 is connected to lever arm 27 projecting from cradle 12. The

activation of hydraulic cylinder 24 results in the rotation of cradle 12 on its trunnion mounts 17.

Car 8 is equipped with wheels 28 which ride on tracks 9. A hydraulic cylinder 29 is mounted below the car 8 so as to shift the car back and forth laterally of the casting machines longitudinal axis. The stroke of the piston of the hydraulic cylinder 29 is made such that when the piston rod is fully extended the cradle 11 Will be positioned directly in line with the machine ladle 7 so that molten metal in a transfer ladle seated in the cradle can be poured into the machine ladle by the actuation of hydraulic cylinder 18. When the piston rod is fully withdrawn cradle 12 will then be aligned with the machine ladle 7 and the contents of a transfer ladle seated in this cradle can be poured into the machine ladle by actuating hydraulic cylinder 24.

Hydraulic cylinder 18 is operated by the piping system illustrated in FIGURE 4. Fluid pressure is applied to the cylinder 18 by means of an air operated valve 30. When air valve 31 is in its normally closed position line 32 is open to the atmosphere. When air valve 31 is opened, line 32 is closed to the atmosphere and air pressure is applied to valve 30 causing it to open thus permitting fluid to flow into the hydraulic cylinder 18. The resulting upward movement of piston rod 20 tilts cradle 11 and molten metal in the transfer ladle is poured into the machine ladle. Air valve 31 is kept open until the required amount of metal has flowed into the machine ladle at which time it is closed. The closing of the threeway air valve 31 cuts off the supply of air to valve 30 and exhausts the line 32 with the result that valve 30 is also closed, stopping the motion of piston rod 20.

The direction of the piston rod may be reversed by means of a second air operated valve 33 in the exhaust line which in turn is controlled by manual operation of normally closed three-way valve 34. When the exhaust valve 33 is opened by opening valve 34, the weight of the cradle 11 and the transfer ladle seated therein forces the piston rod downward The reverse tilt may be stopped at any" Instead it is only necessary to open the identical to that described above, the valves 36 and 39 I corresponding to hydraulic valves 30 and 33 respectively,

34, respectively. To prevent the accidental tilting of the transfer ladle which is in stand-by position out of alignment with'the machine ladle 7, thehydraulic system for the hydraulic cylinder for each cradle is automatically inactivated when the ladle car 8 is shifted so that the cradle is in standby position. The. two hydraulic systems are inter-connected by a four-way valve 41 which. provides for the interconnection of the pressure line and exhaust line with only one system at a time. The operation of this four-way valve is tied in to themovement of ladle car 9 i so that-only the-transfer ladle aligned with the machine ladle may be tilted. This may be accomplished by posiandvalves 37 and 40 correspond to control valves 31 and V could place the transfer ladle in cradle 12 at any time during'the pour from the transfer ladle'in cradle 11. i

As soon as the machine ladle is again empty, it may be filled by opening valve 37 until the desired amount of metal is poured from the transfer ladle in'cradle 12 at which time valve 37 is closed and valve 40 is momentarily opened toget ladle cut back. At any time from the first cast to the last cast from the transfer ladle in cradle 12 V the overhead crane is free to remove the empty transfer ladle from eradle 11 and have it filled with molten metal.

To those skilled in the art'to which this invention relates, many changes in construction and'widely differing embodiments of the invention will suggest themselves. These variations which depart from the illustrative embodiment' set forth herein may be made without departing from the scopeof the. invention as it is hereinafter claimed. l

A centrifugal casting apparatus comprising a cylindrical mold rotatably mounted about 'itslongitudinal axis, a machine ladle for receiving and holding the metal to be cast, meansfor delivering the metal from the machine ladle to the mold, a support mounted adjacent thev machine ladle, said support being movable in the direction 25.

transverse the longitudinal axis of the mold from a first position to a'second position, two cradles mounted on said supportpivotably on trunnions-,.each cradle being adapted to receive and hold a transfer ladle so that it 1 may be tilted by pivoting the cradle on itstrunnions, the

first cradle being'aligned' with the-machine ladle when the 1 support isin said first position and'the second cradle being tioning the four-way valve so that its operation lever42 will be engaged by a protrusion 43 on ladle car 8 as illustrated in FIGURE 3. 1

In operation, atransfer ladle containing hot metal is.

placed in cradle 11. The transfer ladle is tilted byopening valve 31 until the machine ladle is full at which time valve 31 is closed and valve 34.is-momentarilyopened to give a slight reversal of tilt to the transfer ladle. This results in a clean cutolf of the pour and leaves the transfer ladle tilted to a poistion where pouring may be. commenced by a very small movement of the ladle. As soon as a casting cycle is completed, the machine ladle is again filled by opening valve 31 until the required amount of metal has been transferred to the machine ladle at which time valve 31 is again closed and valve 34 is momentarily opened. This procedure isrepeated until the transfer aligned with the machine ladle when the support is in said second position, and a hydraulic cylinder connected between each c'radle and the support for pivoting each ladle is empty at' which time the ladlecar is shifted transversely by means of hydraulic cylinder 29 until atransfer ladle which has been placed in cradle 12 (shown indotted linesin FIGURE 3) is aligned with the machine ladle. 7

It is readily apparent that the overhead crane operator cradle independently of the-other, the hydraulic cylinders.

being connectedto a hydraulic system. in such a manner as to permit the operation of only one hydraulic cylinder at a time, the hydraulic cylinder inoperation at any time being connected to the cradle in alignment with the machine ladle.

References Citedby the Examiner UNITED STATES PATENTS 1,008,406 11/11 Davis 2282 2,458,236 1/49 Wolff .l 22-79 2,683,295 7/54 Howlett etal 2282 2,836,309 5/58 McFeaters 214+18 2,849,128 8/ 58 Sloss 1 214---23 2,922,205 1/60 Deakins et al. 22"82 WILLIAMS]. STEPHENSON, Primary Examiner. DAVIDjL. RECK, MICHAEL V. BRINDISI, Examiners.

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