US2409779A - Apparatus for introducing molten material into molds - Google Patents

Description

Oct. 22, 1946. H. E. M WANE ET AL 2,409,779

APPARATUS FOR INTRODUCING MOLTEN MATERIAL INTO MOLDS Filed Oct. 2, 1942 4 Sheets-Sheet l N 3 100144304 HAW/er 5/7W6WE #116 KH 1946- V H. E. MCWANE ETIAL APPARATUS FOR INTRODUCING MOLTEN MATERIAL INTO MOLDS Filed Oct. 2, 1942 4 Sheets- Sheet 2 Oct, 22,3946.

H. E. MCWANE ET AL APPARATUS FOR INTRODUCING MOLIEN MATERIAL INTO MOLDS Fild Oct. 2, 1942 4 Sheets-Sheet 3 17 Ill/l occzz 1946. 2,409,779

H. E. M wANE ET AL APPARATUS FOR, INTRODUCING MOLTEN MATERIAL INTO MOLDS Filed Oct. 2, 1942 4 Sheets-Sheet 4 v Patented Oct. 22, 1946 APPARATUS FOR INTRODUCING MOL'I EN MATERIAL INTO MQLDS Henry McWane and Hugh K. M cGavcck, Lynchburg, Va said McGavock assignor to'said Application October 2, 1942, Serial No. 460,566. 3 Claims. (01. 122-19) The present invention relates .to a method and apparatus for introducing molten metal into the casting cavity of molds and more particularly to a method and apparatus for introducing the metal into thev casting cavity of a permanent metal mold by so-called top-gating.

Heretofore much difficulty has been experienced in producing a completely satisfactory chilled casting in a metal mold when top-gating was used. This is primarily due to, the fact that the pouring has been done by hand from a conventional foundry ladle. This hand pouring causes a parabolic flow of molten metal and, due to the human element involved, the metal is not introduced into the cavity at a controlled rate of flow or at a controlled velocity.

We have found that to produce a casting that will be properly chilled and free from air holes and other flaws, the streamof the molten metal enteringthe mold gate must first be centered properly directly over the center of the gate. Moreover, the size of the stream of molten metal must be controlled and more specifically, it must be confined to a size that is less than that of the gate. In other words, the section of the stream of molten metal must be less than the section of the mold gate. This is in order that the metal, when entering the gate, will not contact and freeze to the surface of the gate, thus restricting its size or, in extreme cases closing it entirely. In addition, the velocity of the stream of molten metal must be controlled to prevent undue agitation and in trapping air in the casting. That is to say, the variations in the velocity of the metal stream should be controlled .to provide the best casting and similarity between the original and all subsequent castings. Lastly, the amount of metal th t, is permitted to flow into the mold has to be controlled within relatively close limits and suflicient metal should be allowed to flow from the ladle to fill completely the casting cavity without overflowing the gate.

In its broadest sense, our invention is directed to the idea of admitting a given amount of molten metal into the casting cavity at a controlled rate of flow and at a ,con-trolled velocity in a stream less in section than the section of the gate positioned directly over .the center of the gate, thereby affording a casting free of air holes andwith a uniformity of chill.

In its more limited application and with the specific embodiment shown herein, we provide a ladle that is tilted upon trunnions and which includes a pair of bowls disposed at right angles to ea h other: 9. of the e i w ge 2. basin and the other or thebpyvls is a retaining basin. Incorporated with retainin b flisin and arran ed at ub tan ia y, righ slstherei to is a po rin baSm th t i al bra e 5 mild a quantity of molten metal either egual'to or slight- 1y. more than. the m tal. eraser il t il -casting.- V

Fitted within the pouring basin is a nozzle havmg an annular step ed here t e me r' of which is governed by thesize of the stream of molten metal that is necessary. A" sea'fi's'j forme i the u pe nd i the nozzle adapted to be closed by a reciprocating stbpp'er, which can be actuated by any suitable mean-ti" During operatiom-the ladle is movedsd that the charging bowl willb e in substantially a horizontal plane and the measuring tewrwm be in the vertical plane, t this position measuring basin and the discharge nozzle will alsobe" disposed vert a ly. nd the: 150365316551 ktthen mtmeucedi t therqwt The ladle is then moved about its trunnions so that the Charging bowl will be in tile-vertical lane and the measuring bowl will bein thel'ioriz ntal plane. thereby, en b the 14 m l to flow from the charging bowl" into'themeas urine bowl. The 1 1e is then" returned to"its initial position and the metal with'lthe exception of that which fills the pouringbasm'wm fiowinto the charging bowl.

At this point the pouring basin is completely filled and the stopper closes the dischargenozzle. Means are then operative to elevate the stopper the required distance a'nd'the molten metal then flows from the pouring basin 'dijrectlyinto the penter or ,the gate at afcontrolled 'rate of flow and at acontrolled velocity.

After a predetermined perliod'of time means are effected to lower the stopper to arrest' the flow ofmolten metal so that there will be a substantial pool of metal in the basin after the casting cavity has been filled completely. It is also advisable to incorporate with .the control means for the stopper, a mechanism whereby the amount a of lift of the stopper canbe regulated to control the rate of pouring. This supplemental adjustpletely free from air holes and other flaws which are due to pouring.

Another object is to provide a method and apparatus for introducing molten metal into the casting cavity of a mold at a controlled rate of flow and at a controlled velocity in a stream less in section than the section of the gate.

Yet a further object is to provide a ladle which is so constructed that the molten metal will be maintained therein at the desired temperature and the metal will be introduced into the casting cavity in a stream less in section than the section of the gate at a controlled rate of flow and at a controlled velocity.

Still a further object is to provide a method and apparatus for introducing molten metal into the casting cavity of a metal mold by topgating that will enable all of the castings to be uniform in metallurgical structure.

In the drawings in which like numerals designate the same or similar parts:

Figure l is a view in side elevation of a casting machine having incorporated therewith my novel charging and pouring ladle.

Figure 2 is a fragmental longitudinal sectional view taken through my novel charging and pouring ladle.

Figure 3 is a transverse sectional view taken along the line 3-3 of Figure 2 looking in the direction of the arrows.

Figure 4 is a sectional view taken along the line 44 of Figure 2 looking in the direction of the'arrows.

Figure 5 is a fragmental sectional view showing the stopper for closing the metering cup and its mode of attachment to its support means.

Figure 6 is a View taken along the line 6-3 of Figure 5 looking in the direction of the arrows.

Figure 7 is a diagrammatic representation of the time circuit for controlling the operation of the stopper.

Figure 8 is a fragmental view in side elevation of the charging and pouring ladles having incorporated therewith an electrical are for maintaining a constant heat therein.

Figure 9 is a sectional view taken along the line 9-9 of Figure 8 looking in the direction of the arrows.

As clearly illustrated in Figure 1, the casting machine comprises a frame I, a fixed mold bo y 2, a movable mold body 3 and a piston and cylinder assembly 4 that is adapted to move the mold part 3 toward and away from fixed mold part 2. When the mold parts 2 and 3 are in the operative position (Figure 2), they define therebetween a pouring gate 5 that communicates with a casting cavity 6. In the copending application S. N. 422,912, filed December 13, 1941, by Henry E. McWane, the structure and operation of the casting apparatus is described and hence no further' description of the apparatus is necessary here.

Our novel ladle designated generally 1 cornprises a molten metal charging bowl 8 and a filling bowl 9 and in Figure 2 it will be noted that these bowls are positioned substantially at right angles to each other. The charging bowl 8 is supported for tiltable movement about the horizontal axis as shown by the numeral It in brackets H which are secured to the fixed mold part 2. Extending from the pivot I is a handle l2 that will enable the bowl 8 to be moved for- .wardly about its pivot to pour excess molten metal therefrom.

Projecting upwardly from each bracket 1 l arcuate arm It in which is jo-urnalled for tilting movement about the horizontal axis as indicated at M, the filling bowl 9. Secured to the pivot I4 (Figure 3) is an arm i which is pivoted as shown at is to a push-pull link II. The arm may be detached from the link by a connection Ill. The opposite or free end of the link ii is hinged to the upper end of a bracket 18 supported by the movable mold part 3 as at Hi.

In Figure 2, it can be seen that the ladle 1 comprises an outer metallic shell or casing 20 which contains the charging bowl 8 consisting of an insulated section 2i and a lining 22 of a suitable refractory material. A cover 24 is hinged to the top of the bowl 8 as shown at 23 for the purpose of permitting molten material to be admitted into the bowl.

A discharge spout 25 is provided at the front end of the bowl and the cover 26 fits closely into the spout when it is in its closed position.

The filling bowl 9 also contained within the outer metallic shell 20 has an insulated section 21 and a refractory liner 28.

The interiors of the bowls S and 9 communicate with each other. A conical metering cup 39 is provided in the bottom wall of the bowl 3 and it is also made of a refractory material and preferably it is replaceable. The capacity of this cup is somewhat in excess of the capacity of the casting cavity 3 since, as a practical matter, it is not desirable in casting operations to empty completely a ladle. This is due to the fact that, if emptied, there is always a small amount of residue in the form of beads or pools and consequently it is desirable to have a substantial pool of molten metal in the cup 30 after the cavity 5 has been filled completely.

Fitted within the apex of the cup 33 (Figure 5) is a pouring nozzle 3| and it can be seen that the nozzle is formed of a refractory material. The nozzle is provided with a stepped bore 32 which communicates at its upper end with the metering cup 30. The inner end of the nozzle is countersunk to form a conical valve seat 33 and the outer end is enlarged as shown at 34 to a diameter that is substantially greater than the diameter of the stream of molten metal. By having the enlarged diameter 34, an insulating sleeve is formed about the spout and the molten metal is prevented from freezing in the nozzle and stopping the bore. The pouring nozzle 3| is subjected to considerable wear during the casting process and by having this unit replaceable will enable the worn nozzle to be removed and replaced in a minimum of time.

In order to close the bore 32, we employ a stopper 35 that is made of a refractory substance and which is capable of vertical reciprocation. The lower end of the stopper is tapered as shown at 36 to fit closely within the conical valve seat 33. The upper end of the stopper extends through an opening 3'! formed in the upper wall of the bowl 9 and is fixed within a socket 38 as shown at 38'. The socket 38 is bolted eccentrically as shown at 39 in a flange 40 formed on a support element 4|. The support element 4| is attached as shown at 42 to an armature 43 which in turn is mounted for sliding movement in slide tracks 44 secured to a bracket 45 supported by the metal shell 20 of the filling bowl 9. The upper end of the armature extends into a solenoid S5 of conventional construction and is provided, of course, with the necessary coil 41. An adjustable stop 41' is positioned in the upper end of the sleeve to act as is an a limit for the upward movement of the arma- 5 ture- 43- Whenthecoil4l' is'energized, the armature-43 is drawn upwardly and simultaneously the stopper 35 wi1l bemoved upwardly to open the bore- 32. Surrounding the armature 44 is a heli cal spring 48fthat is adapted to force the armature 44 downwardly when the flow of current to the coil is arrested.

In operation the ladle I is moved so that the charging bowl 8 is in the horizontal plane and the'filling bowl 9 i's in the vertical plane. When thebo wls are in these positions, the metering cup SB a-n'd the discharge nozzle ill are also vertically disposed and the rim of the cup is in a position above the rim of the charging bowl 8. The cover 24 is thenopened and thenecessary amount of molten-metalis' admitted into the bowl 8 Whereupon the cover is moved to its closed position. The casting machine is then set in operation and as the movable mold part 3 is moved away from the fixed mold part 2, the ladle will be moved about its pivot l4 by virtue of the arm I5 and the link l'l, meaning, of course, that the charging bowl will be moved to the vertical position and the filling bowl will be in the horizontal position so that the molten metal will flow into the filling bowl. As the casting cycle continues, the movable mold part 3 will again be moved toward the fixed mold part 2 and the ladle will once again be moved about its pivot l4 so that the charging bowl 8 and the filling bowl 9 will again assume the horizontal and vertical positions respectively. At this point, all of the molten metal in the pouring bowl 9 will flow back into the charging bowl 8 with the exception of the molten metal in the 'metering cup 30. At this point, the metering cup and the discharge nozzle are positioned directly above the filling gate 5 and the apparatus is ready for pouring. However, the bore 3| is closed by the stopper 35.

In order to energize the solenoid winding 41 at this time, we provide a segment 60 secured to a shaft 6| that is adapted to be driven by motor 62 through worm wheel 63 and worm gear 64. A source of electrical energy 65 has one of its leads in contact with ring 66 on shaft Bl as shown at 61. The other lead 68 communicates with one end of the winding 41 and the other end of the winding 41 communicates with a contactor 69 through lead 10. As soon as the segment makes contact with the contactor 69, energy is supplied to the winding 41 which will draw the armature 43 upward against the action of the spring 48 and simultaneously move the stopper 35 upwardly to enable the molten metal in the metering cup to flow through the bore 32 into the casting cavity 6. By the time the casting cavity 6 is filled, the segment 60 has completed its cycle, and contact is broken between the segment and the contactor 69. Consequently, the solenoid winding 41' is de-energized and the spring 48 forces the armature 43 and the stopper 35,downwardly once again closing the bore 32 and arresting the fiow of metal into the cavity.

While we have shown the use of a separate motor to supply current to the solenoid winding 41, it is, of course, obvious that this mechanism may be synchronized with the unit for moving the movable mold part toward and away from the fixed mold part. In any event, any means which will energize the solenoid winding for the amount of time necessary to permit the casting cavity to be filled may be employed. In lieu of the solenoid arrangement for operating the stopper 35, it is, of course, obvious that other control devices, such as a pneumatic or hydraulic cylinder may be employ'd; y Inthe embodiment shown in Figures 8 and 9, we providean electric arc to maintain a desired temperature within the ladle 1'. In construction and operation, the ladle l is identical with the ladle T. The only differencebetween these construotions is that we employ carbons 50 that proje'ct into the interior of the bowl 9, above the level of the molten metal, and a feed mechanism 5| which is operativelyconnected with the carbons 50, and inasmuch as thisstructure is conventional, it is not necessary to describe it in detail. i

It will be appreciated from the foregoing details that wehave provided a ladle that will permit the manufacture of a casting that is properly chilled and completely free from air holes and other flaws. Furthermore, the molten metal is admitted into the casting cavity at'a controlled rate of flow and at a controlled velocity in a stream whose cross-sectional area is less than that of the mold gate. With our invention all castings will be uniform in metallic structure.

While we have shown and described the preferred embodiment of our invention, we wish it to be understood that we do not confine ourselves to the precise details of construction herein set forth by way of illustration, as it is apparent that many changes and variations may be made therein, by those skilled in the art, without departing from the spirit of the invention, or-exceeding the scope of the appended claims.

We claim:

1. The combination with a separable mold for producing castings, said mold having a stationary part anda movable part cooperating therewith to provide a casting cavity, of a ladle comprising a charging bowl, a filling bowl communicating therewith and arranged at substantially right angles thereto, a metering cup communicating with the filling bowl and adapted to hold a quantity of metal either equal to or slightly more than the metal necessary for a single casting, means carried by the stationary mold part to mount the ladle thereon for independent tilting movement about the respective axes of said bowls, means carried by the movable mold part and operatively connected with the ladle to tilt the same about the axis of the filling bowl whereby molten metal in the charging bowl will flow therefrom into the filling bowl to fill the metering cup, a nozzle communicating with the filling cup for discharging metal therefrom into the casting cavity, stopper means for controlling the fiow of metal from said cup, and additional means for tilting the ladle about the axis of the charging bowl for discharging residue metal therefrom.

2. The combination with a separable mold for producing castings, said mold having a stationary part and a movable part cooperating therewith to provide a casting cavity, of a ladle comprising a casing, a lining therefor consisting of an insulatin material adjacent the casing and a refractory material adjacent the insulating material, said lining forming a charging bowl and a filling bowl communicating therewith and arranged at substantially right angles thereto, a refractory metering cup communicating with the filling bowl and calibrated to hold a quantity of metal either equal to or slightly more than the metal necessary for a single casting, a refractory nozzle communicating with the metering cup for discharging metal therefrom into the casting cavity, means carried by the stationary mold part for mounting the ladle thereon for independent tilting movement about the respective axes of said bowls, means carried by the movable mold part and operatively connected with the ladle to tilt the same about the axis of the filling bowl whereby metal in the holding basin will flow therefrom into the filling basin to fill the metering cup, means for controlling the flow of metal from the filling cup into the casting cavity, and additional means for tilting the ladle about the axis of the charging bowl for discharging residue metal therefrom.

3. A ladle for introducing molten metal into the casting cavity of a mold to produce a casting comprising a semi-cylindrical basin adapted to hold a supply of the molten metal, a second semi-cylindrical basin substantially at right 8 angles thereto and communicating therewith, a metering cup communicating with the second basin and adapted to hold a quantity of molten metal either equal to or slightly greater than the metal necessary for a single casting, means supporting the ladle for independent tiltin movement about the axes of each of said semicylindrical basins, means for rotating the ladle about the axis of the second basin to cause metal to flow from one to the other of said basins to fill the metering cup, a nozzle for the cup to discharge metal therefrom into the casting cavity of the mold, and additional means for rotating the ladle about the axis of the first-named basin for discharging residue metal therefrom.

HENRY E. McWANE.

HUGH K. McGAVOCK.

Images