US3367619A - Reversible mold for casting high melting point metals - Google Patents

Description

Feb. 6, 1968.

E. Q. SYLVESTER 3,367,619

REVERSIBLE MOLD FOR CASTING HIGH MELTING POINT METALS Filed April 20, 1965 2 Sheets-Sheet 1 g3 flwenz oj aawmm @wze/v WZ raw/ i Feb. 6, 1968 E. Q. SYLVESTER 3,367,619

REVERSIBLE MOLD FOR CASTING HIGH MELTING POINT METALS Filed April 20, 1965 2 Sheets-Sheet 2 i I s a!) a I United States PatentO 3,367,619 REVERSIBLE MOLD FOR CASTING HIGH MELTING POINT METALS Edmund Q. Sylvester, 2749 Landon Road, Shaker Heights, Ohio 44120 Filed Apr. 20, 1965, Ser. No. 449,492 Claims. (Cl. 249-118) ABSTRACT OF THE DISCLOSURE Mold apparatus comprises two pairs of billets 34 and 36 seated on a bed 6 which has gate openings 64, one between each pair of billets. Slabs 1i), seated on the bed, engage a pair of billets and may be lifted by a power cylinder and a power actuated track segment 28 so that the slabs are supported above the bed 6 on bearing 17 and roller 26 whereby power means 23 connected to shaft 22 rotate the slabs 10 to engage the other pair of billets 34, 36 whereupon bearing 17 and roller 26 are lowered to re-engage the slabs 10 with the bed 6. The slabs are clamped against each pair of billets by power actuated wedges 30 received in aligned slots 16 or 18 of brackets 12 or 14 attached to the slabs.

This invention relates to the foundry art and more particularly to the casting of molten material in a mold formed of material such as cast iron or cast steel which due to the heat of the molten material develops tensile stresses on the inside surfaces of the mold and compressive stresses on the outside surfaces of the mold, resulting in a tendency to distortion and cracking which eventually causes mold failure.

In the rolled steel industry practically all steel according to present day practices is poured into a cast iron ingot mold which has a very short service life due to erosion and cracking. The cracking is caused by continuous tensile stress build-up on the inside surfaces of the mold during each pouring. It will be understood that when molten steel is poured into such a cast iron mold the interior mold surface being rapidly heated tends to expand but this expansion is resisted by the massive cooler metal outwardly of the internal mold surface so that the outer mold surface is subjected to compressive stress.

Accordingly one object of the present invention is to devise a method and means for reversing the inside and outside mold surface after each pour to reverse the stress pattern with each pour.

Another object of the invention is to clamp the mold parts together after each reversal to prevent disortion of the mold parts which would otherwise occur during cooling between successive pours.

Still another object of the invention is to shorten the time between pours by making it possible to apply a mold wash to the outside mold surfaces while the mold is being poured or while the molten metal therein is freezing into a casting to be removed from the mold whereupon the washed outside surfaces thereof can promptly be arranged as inside surfaces for the next pouring of the mold.

Yet another object of the invention is to facilitate removal of a casting from the mold by rotating opposed sides thereof out of engagement with the casting While supporting it by end sections of the mold so that the casting may be conveniently clasped by tongs or other convenient means for removing the casting from the mold preparatory to another pouring thereof.

The foreging and other objects of the invention will become apparent from a consideration of the following specification and the according drawings wherein:

FIGURE 1 is a perspective view of a mold apparatus embodying a preferred form of the invention;

, 3,357,619 Patented Feb. 6, 1968 "ice FIGURE 2 is a partial top plan view partly in section along the horizontal plane indicated by line 2-2 of FIG- URE 1; and

FIGURE 3 is a fragmentary sectional view taken in the vertical plane indicated by line 33 of FIGURE 2.

In each of said views certain details may be omitted for the sake of clarity where more clearly seen in other views.

Describing the invention in detail and referring first to FIGURE 1, the mold apparatus disclosed therein comprises a frame 2 supported by columns 4 above a bed 6 having a circular track 8 therearound slightly above the level thereof. A pair of slabs 10, preferably formed of cast steel or cast iron or other suitable material, are slideably supported on the bed 6 and are secured to inner and outer brackets 12 and 14 having apertures 16 and 18 respectively.

The inner brackets 12 are provided with hubs 20 within which shafts 22 are loosely received and are keyed as best seen at 24 in FIGURE 2 for rotating the hubs but permitting relative vertical motion between the hubs and shafts for a purpose hereinafter described.

The outer brackets 14 are supported by rollers 26 on a separable segment 28 of the track 8, and the bottom of each shaft 22 is supported by a bearing 13 actuated by a power cylinder device 15 (FIGURE 3) to engage the bearing 13 with a roller bearing 17 carried by the lower end of the related bottom hub 20, so that the hubs 20 and the track segment 28 (raised and lowered by power means not shown) are simultaneously actuated to raise the slabs 10 above the bed 6 or to lower the slabs into engagement therewith for slideable support thereby at the position shown in the drawings wherein the slabs are clamped into interlocking position shown by solid lines, as by locking wedges 30 insertable into and removable from apertures 16 and 18 as by power cylinder devices 32. It will be understood that the registered apertures 16 and 18 of the brackets 12 and 14 attached to the respective slabs are so formed and arranged that driving of the wedges 30 into these apertures by the power means 32 is effective to clamp the slabs against inner and outer billets 34 and 36.

The billets 34 and 36 are slideably seated on the bed 6 and are tightly compressed by and between the slabs 10 by means of the locking wedges as heretofore described. The inner billets 34 are rotatably mounted on the frame 2 and the bed 6 by top and bottom trunnions 38 and 40. The top trunnion is connected by coupling 42 to a shaft 44 which is operated by a handle 46 to rotate the inner billet between pours to reverse the inner and outer surfaces thereof for the purpose heretofore described.

The outer billet 36 is similarly rotatable by a shaft 48 having a handle 50. The shaft 48 is journaled in a ram 52 which is slideably mounted in a head 54 having a locking bolt 60 to lock the billet at a predetermined spaced distance from the inner billet 34, thereby adjusting the width of the casting to be formed in the mold. The billet 36, when the bolt 56 is released, is adjusted by means of a shaft 58 actuated by conventional power means 61 and connected to the ram for moving it back and forth within the head 54. This adjusting means forms no part of the present invention and is therefore not shown in detail.

The outer billet 36 is also provided with compression rods 59 actuated by a conventional power device 62 to move said rods toward and away from the inner billet 34 as may be required by adjustment of the ram 52.

The bed 6 is preferably formed of graphite or cast iron and comprises a pair of gate openings 64 each of which contains a graphite sleeve 66 within which is a ceramic bushing 68 mated with a gate assembly 69 adapted for connection to a pouring tube (not shown) to fill the mold 3 with molten steel at a non-turbulent fiow rate as described in US. Letters Patent No. 2,990,592, issued May 13, 1959, to H. H. Hursen.

The top of the opening 64 intersects a groove 70 (FIG- URE 1) in the top of the bed, and a cut-off plate 72 is slideably mounted in said groove, the plate having an opening 74 registered with the opening 64 during pouring of the mold. The cut-off plate 72 is actuated as by power cylinder 76 (FIGURE 1) to a position whereas the opening 74 is spaced from the opening 64 after the mold has been poured whereby the plate 72 cuts off communication between the gate assembly 69 and the interior of the mold. This cut-off mechanism is not part of the present invention and thus is not disclosed in detail. However, a typical mechanism is disclosed in detail in US. Letters Patent No. 3,015,863, issued July 29, 1959, to C. F. Strom and Joseph Wszolek.

After the mold has been poured while the parts thereof are in the position shown by solid lines in the drawings, the slabs are raised by elevating track section 28 and bearing 13, whereupon the slabs are rotated 180 by means of the shafts 22 (each actuated by a chain and sprocket 23) to the position shown by phantom lines in FIGURES 1 and 2. In the last-mentioned position of the slabs 10 they are again supported by a movable tr-ack section 28 and are lowered thereby and by power cylinders until the slabs are again slideably seated on the bed 6 whereupon the slabs 10 and the left hand pair of billets 34 and 36 are clamped together by means of the locking wedges 30 before the parts are cooled sufiiciently to warp, crack or distort. The mold is then poured by means of the gate assembly 69 shown at the left of FIGURE 3. This sequence may be repeated indefinitely.

Thus, it will be understood that the stresses on the inner and outer sides of the slabs 10 and the billets 34 and 36 are reversed during each pouring, thereby ensuring long life of these parts of service and permitting more rapid cycles than heretofore possible utilizing the same mold parts.

It will also be understood that the inner surfaces of the slabs and billets which define the mold cavity indicated at 78 are preferably coated between the pours as by spraying with a suitable mold wash or by attaching ceramic liners 80 (FIGURE 1) as by clips 82. Where spraying is used the outer sides of the slabs and billets can be coated during the pour or while the molten metal in the mold cavity 78 is freezing, thus speeding up the cycle.

Another feature of the invention is the ease with which the casting 79 formed in the mold cavity 78 may be removed after the slabs 10 have been rotated out of engagement with the casting 79 as shown in FIGURE 1 wherein it will be seen that the casting 79 is itself a steel slab such as is commonly rolled to finished form in a finishing mill. The casting 79, after the slabs 10 have been removed therefrom, is engaged by conventional toggle clamps 86 carried by a crane hook 88 by means of which the casting 79 may be quickly and easily elevated from the bed 6 and transported from the mold apparatus to a storage area or to a mill for immediate rolling to finished form.

What is claimed is:

1. Mold apparatus comprising a bed having spaced gate apertures therethrough, two pairs of elongated billets slideably seated at their lower ends on the bed with the billets of each pair having one of said apertures therebetween, a pair of elongated slabs slideably seated at their lower ends on said bed and clamping one pair of said billets to define therewith a mold cavity along inner surfaces of said slabs and last-mentioned billets, hubs on corresponding sides of said slabs, shafts loosely received within respective hubs and having keys loosely received within corresponding keyways of respective hubs to accommodate raising and lowering of the slab, means for raising said slabs from said bed, said shafts being rotatable in opposite directions to rotate said slabs when so raised to engage both billets of the other pair along surfaces of the slabs opposed to the first-mentioned surfaces thereof.

2. Mold apparatus according to claim 1 wherein means are provided for rotating each of the billets after being released from the slabs.

3. Mold apparatus according to claim 1 wherein brackets are attached to respective hubs and wherein said brackets have openings, respectively, which are aligned when the slabs are engaged with the billets of either pair, and wherein a locking wedge is received within said aligned openings, and wherein power means urge said locking Wedge into said openings to clamp the slabs against the engaged billets.

4. Mold apparatus comprising a fiat bed interrupted by spaced gate apertures, two pairs of elongated cast ferrous metal billets having substantially flat bottoms slideably seated on the bed, with the billets of each pair having one of said apertures therebetween, a pair of elongated cast ferrous metal slabs having substantially flat bottoms slideably seated on said bed and clamping one pair of said billets along inner surfaces of said slabs to define a mold cavity, means for raising the slabs above said bed, and means for moving the slabs while so raised to engage the other pair of billets along surfaces of the slabs opposed to the first-mentioned surfaces thereof.

5. Mold apparatus comprising a flat bed, a pair of slabs having flat bottom surfaces slideably seated on the bed, spaced gate openings through said bed, two pairs of billets having fiat bottom surfaces slideably seated on said bed, with one gate opening between the billets of one pair and the other gate opening between the billets of the other pair, and means for moving the slabs to a position whereat they engage one pair of billets therebetween along mutually facing sides of said slabs and to another position whereat the slabs engage the other pair of billets along opposite sides of said slabs.

6. Mold apparatus according to claim 5 wherein each slab is provided along opposed edges thereof spaced from the bed with brackets each having spaced apertures, certain apertures of respective brackets being in alignment when the slabs are in one of said positions thereof and other of the apertures of said brackets being in alignment when said slabs are in said other position thereof and wherein locking wedges are tightly received within the aligned apertures in each of said slab positions to clamp the slabs against the billets.

7. Mold apparatus comprising a substantially fiat bed, a plurality of slabs having substantially flat bottom surfaces seated on the bed and each mounted at one vertical edge on a bracket mounted on the bed for pivotal movement of the slab thereabout, spaced gate openings through said bed, a plurality of billets having substantially flat bottom surfaces seated on said bed, with the gate openings positioned between billets of respective pairs, and means for effecting said pivotal movement to move the slabs to a position whereat they engage the bed and also engage one pair of billets along mutually facing sides of said slabs and to another position whereat the slabs engage the bed and also engage another pair of billets along opposite sides of said slabs.

8. Mold apparatus comprising two pairs of spaced billets, a pair of slabs clamping one pair of the billets therebetween along mutually facing surfaces of the slabs, bracket means mounted on the bed for pivotally moving the slabs to clamp the other pair of billets therebetween along opposite surfaces of the slabs, a bed supporting the billets and the slabs when clamped against a pair of the billets and spaced gate openings through the bed, each pair of billets having a gate opening therebetween.

9. Mold apparatus comprising a plurality of spaced billets, a plurality of slabs engaging a pair of the billets therebetween along opposed surfaces of the slabs, said slabs and billets being seated on a bed to define therewith a mold cavity, roller means attached to said slabs, means engageable with said roller means to raise the slabs from 5 said bed, and motor means operatively connected to the slabs for moving them while so raised, to engage another pair of the billets along other opposed surfaces of the slabs.

10. Mold apparatus comprising a plurality of billets, a plurality of slabs engaging a pair of the billets therebetween along opposed surfaces of the slabs, said slabs and billets being seated on a bed to define a mold cavity, roller means for supporting the slabs, and means operatively connected to the slabs for rotating them on fixed axes, respectively, to engage another pair of the billets along other surfaces of the slabs.

References Cited UNITED STATES PATENTS 971,554 10/1910 Parsons 249-162 1,302,277 4/1919 Bangs 249-167 Busse 249-167 Gotze 249-102 Eppensteiner 249-158 X Bungeroth et al. 164-280 Bright 164-131 Colombo 249-158 X Sylvester 249-174 X FOREIGN PATENTS Great Britain.

I. SPENCER OVERHOLSER, Primary Examiner.

15 V. K. RISING, Assistant Examiner.

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