US1752280A - Method and apparatus for casting metal - Google Patents

Description

March 25, 1930. s. s wT 1,752,280

METHOD AND APPARATUS FOR CASTING METAL Filed July 13, 1928 2 Sheets-Sheet l Embomioz I V W Marh 25, 1930. E. s. SAWTELLE 1,752,280

METHOD ANDAPPARATUS FOR CASTING METAL Filed July 13, 1928 2 Sheets-Sheet 2 -Patented Mar. 25, 1930 UNITED STATES,

PATENT OFFICE EL'MER S. SAWTELLE, OF CINCINNATI, OHIO, ASSIGNOR TO THE SAWBROOK STEEL CASTINGS COMPANY, OF LOGKLAND, OHIO, A CORPORATION OF OHIO METHOD AND APPARATUS FOR CASTING METAL Application filed July 13,

This invention relates generally to the art of casting metal and is particularly directed to an improved method of casting and an apparatus for use in the method.

It is of extreme importance in many castings that the metal be entirely free of shrink holes and pits and that certain heavy sections of the casting be extremely dense so that these'sections may be subsequently ground down or faced to accurate dimension without encountering holes or pores which would render the casting unfit for use.

The present invention residesin the combination, use and construction of a novel form of mold for forming a riser extrinsic of the article mold cavity, the riser having any number of snouts or extensions leading out from its lower end to the flanges or parts of the casting in which density is especially required and to which more metal must be di-' rected than to other given areas.

Broadly speaking, the present improvement, in addition to the apparatus now in use, is in the above described riser which may be shaped and disposed within the sand in any desired relation to the mold for an efficient disposition of the metal, the inetal 1n the riser generating pressure at the requlred points due to its weight. It is also possible to so dispose the element of thepresent invention in such relation to a given num= ber of molds to be filled as to achieve the proper directing of the molten metal and the resultant density in a number of individual castings, the molds thereof being disposed radially of the'riser.

This invention, therefore, providesa formed riser of this nature providing a head pressure chamber located above the. casting cavity, the molten metal preferably being delivered directly into the mold cavity and rising into the head chamber through radial ancillary passageways extending upwardly from those portions of the mold forming the heavy sections of the casting. The result achieved is that the lighter sections of the casting coolfirst, shrinkage therin is compensated for by the supply ofmetal from the eavy sections under head pressure, and the to heavy sections cooling under the gravity acbe more fully set forth 1928. Serial No. 292,427.

The use of centrifugal action in the casting method and apparatus herein disclosed has been found especially adaptable and it is preferred in the use of the apparatus disclosed in the foregoing description. The centrifugal force in the present instance is applied to generate pressure in the heavy sections of the casting through extrinsic conduits or passageways leading from a heavy head of metal. This centrifugal force is directly applied from the center of the head pressure chamber by rotating the mold on a center coincident with the head pressure chamber or riser body and is exerted through radial passageways, packing the heavy sections and insuring dense casting therein.

It is, therefore, an object of this invention to provide an improved method of casting, the method being adapted to the formation of castings having extremely heavy, irregular peripheral portions.

It is another object of this invention to provide an improved apparatus for casting articles of metal and to provide a pattern element, for use therein for forming ancillary casting channels of unique arrangement, the I principle in the use of which is the same in all lnstances only necessitating an arrangement and formation of the element to suit the given article to be cast and in result to provide an improved method of casting through the use of the apparatus described in general.

Still another object is to provide an improved method andv apparatus for forming metal castings which is especially adapted for centrifugally generating relatively great casting pressures at various points in the castings being formed. o

Other objects and certain advantages will in a description of the accompanylng drawings, forming a part of this s ecification, in Whl0l11-- 4 Figure 1 is atopplan view of thecasting apparatus showing a completed castmg, the upper cope flask being removed.

igure 2 is a sectional view taken on 11116 2--'-2, Figure 1, illustrating the completely formed casting formed within the molding apparatus and mounted on a table for revolving the mold, the riser portion of the 'mold being shown in its cast form prior to removal from the .casting body.

Figures 3 and 4, end view and plan view respectively, illustrate the formed casting removed from the mold. I

- Figures 5 and 6, side and plan views respectively, illustrate an arrangement of the riser relative to a plurality of articles to be cast for dlrecting the metal to the respective flanges thereof, the casting being disposed radially of the axis of rotation or center of the riser.

The castings shown in the disclosure of the drawing made by this method and apparatus are in some instances valves and in others valve yoke's, formed of steel. For this type of article it is especially desirable that density be procured in the casting, these castings being ada ted for high pressure duty and since the anges must be faced or ground to accurate dimension it is requisite that there be no pockets or cavities in the flanges.

As disclosed in Figures 1 and 2, the mold, indicated at 1, is mounted on a rotating table 2, this table being revolved by means of a bevel gear 3 pinned to the central standard 4 thereof, and driven by means of a bevel pinion gear 5.

The mold, constructed according to the usual foundry practice, comprises a circular flask formed in two pieces connected on a horizontal joint, the lower thereof referred to as the drag flask 5 and the upper asthe cope flask 6.

The flask has the respective sand molds formed therein indicated at 7, and the sand packed or rammed in the usual manner around a pattern.

, As shown in Figures 1 and 2, the sand of the cope flask is formed around a riser pattern. The views may be treated as showing 50 the casting immediately after formation and Enor to removal from the mold, the riser I eing filled with metal and indicated at 9.

Means for clamping the respective mold halves together is not shown herein but may 55 be of any conventional type. The core, constructed in the usual manner and inserted after the patterns are drawn from the sand, is indicated at 10. The core is shown in diarammatic form since it forms no part of this 60 mvention. I

\ The casting shown in Figures 1 and 2 is rapidly, but since the pressure is being generthat of a valve, being generally indicated at- 11. This valve provides a body having thin walls suitably cored out, and an attaching flangeat the ends of each of the respective.

passageways of the valve, these flanges being indicated in each instance at 12. The flanges are of considerably greater relatlve th1ck ness as compared to the body walls, and being attaching flanges are of much greater diameter, than the connecting valve body portions, consequently requiring a greater amount of metal.

In the molding operation illustrated in these views, a core indicated at 13 may be set between the riser and the article cavity after the riser pattern is withdrawn from the upper or cope flask, or the riser pattern may be sectional for withdrawal without disturbing the sand wall between the riser and the article cavity when the sand is packed around both the riser pattern and the article pat tern and fills the space therebetween dispensing with a core. r I y The riser, as formed, comprises a head pressure chamber'of relatively large dimension indicated at 14, and radially extending snouts or ancillary passageways 15 extending downwardly and outwardly from the head pressure chamber portion, connecting to each flange region of the article mold cavity.

Molten metal is poured directly into the mold cavity through a pouring gate or passageway 16 extending downwardly through the cope flask to the joint of the mold and forked to extend along the joint to each end of the mold cavity as indicated at 17.

With the respective cavities formed and the cores set. the molten metal is poured into the mold, rising upwardly through the interior of the article mold cavity, upwardly through the ancillary passageways, filling the head pressure chamber. When the 'casting is small the pouring through the article mold cavity is continued until the metal levels with the top of the riser. but in casting larger pieces this pouring is discontinued prior to the levelling and molten metal then is introduced through the riser to fill the same. This latter method provides a head of hotter metal, cooling exceedingly slow due to the quantity, and precluding any possibility of the head of metal cooling first which is essential as 'outlined hereafter. Immediately after pouring ated'in the flanges, metal is supplied to the body to take care of shrinkage therein. The centrifugal action induced by the rotation of the mold, inasmuch as the article cavity and in the flanges, this being the result sought,

inasmuch as the metal in the flanges must be extremely dense for facing operations as herebefore stated.

The flanges as they cool, draw their supply for shrinkage from the ancillary radially or laterally disposed passageways of the riser,

- and the large head pressure chamber of the riser cools last since it has the greatest mass of metal therein. After the crude article is removed from the mold, the respective cores are removed and the riser section of cast metal is cut away from the article. It will be understood that if a sufficient head of metal is used in the riser the weight thereof will force the molten metal to the desired regions and shrinkage will be compensated for in the same manner as aforesaid- The cast article as drawn from the mold in its crude form is illustrated'in Figures 3 and 4.

Figures 5' and 6 illustrate a method and apparatus for casting a plurality of castings 18 by the use of the present invention. The mold and the rotating table are not shown, the table being of sufficient diameter to support a flask large enough to contain'a plurality of castings radially disposed from a center or axis of rotation.

The riser used in this instance is indicated at 20, being shownin the form of a cast portion joined with the crude castings. The pouring of the metal as in the other cases is directly into the article mold cavity. The articles to be cast, as shown in this instance, are valve yokes, this type of casting having a heavy flange and body portion indicated at 21 at one end thereof, and feet 22 extending outwardly from the heavy flange and body portion of the casting.

The riser, mounted on the axis of mold rotation, comprises the head pressure portion indicated at 23 and the laterally extending snouts 24, these snouts connecting to the flange portions of the casting.

Although only two castings have been shown in these views, it is readily understood that any number may be radially disposed from the riser head pressure chamber and fed from respective laterally disposed snouts.

Having described my invention, I claim:

1. A casting apparatus, comprising, a rotatable mold having a mold cavity forme therein, said cavity having regions of relatively greatercubical dimension, said mold having a head pressure chamber formed on its axis of rotation above said mold cavities, and a plurality of ancillary supply passageways extending from the head pressure chamber to the mold regions of relatively greater cubical dimension.

2. In a casting apparatus, a mold, means for revolving said mold, the molding cavity of said mold providing outwardly disposed regions of greater cubical dimension than the central or main portion of the cavity, said mold having a riser cavity formed therein, said cavity disposed on the axis of mold rotation, and having radially disposed snout extensions leading to said outwardly disposed zones of the mold cavity, and means for supplying the metal to be cast directly into the molding cavity;

3. A rotary casting apparatus, comprising, a mold having an article molding cavity formed therein, means for rotating said mold on a center coincidental with the center of said mold cavity, said mold having a pouring gate entering said article molding cavity and a riser cavity centrally disposed relative to and in communication with the peripheral regions of the article mold cavity.

LA casting apparatus, comprising, a rotatable mold having a cavity formed therein, said cavity disposed on the axis of mold rotation and having outwardly disposed regions of greater cubical dimension, a pouring gate for said mold entering directly into the mold cavity, said mold cavity having a head pressure chamber, located on the axis of mold rotation, formed therein, and lateral passageways extending to the article mold cavity regions of greater cubical dimension.

5. A molding apparatus, comprising, a rotatable mold having a molding cavity formed therein providing regions of relatively greater cubical dimension, and a chamber for containing a source of ancillary supply located on the'axis of mold rotation and in communication with each region of greater cubical dimension through individual passageways, and means for feeding the metal into the mold.

6. A rotary casting apparatus, comprising, a mold having an article molding cavity formed therein, means for rotating said mold, said mold having a pouring gate entering said article-molding cavity and a riser cavity in communication with the atmosphere and with the peripheral regions of the article mold eavit 7. A casting apparatus, comprising, a rotatable mold having an article cavity formed therein, said cavity having outwardly dis-. posed regions of greater cubical dimension, 2. pouring gate for said mold, said mold havd ing a head pressure chamber, located on the axis of mold rotation, formed therein, and lateral passageways extendmg tov the article III mold cavity regions of greater cubical dimension.

8Q A molding apparatus, comprising, a mold havinga molding cavity formed therein providing regions of relatively greater cubical dimension, and a chamber for containing a source of ancillary supply located above and having individual passageways in comimunication .with each region of greater cubi- ,lcal dimension, and means for feeding the metal into the mold.

, 9. A casting apparatus, comprising, a mold having a mold cavity formed therein, said cavity having regions of relatively greater cubical dimension, said mold having a head 'pressure chamber formed above said mold cavity, and a plurality of ancillary supply passageways extending from the head ressure chamber to the mold regions ofrelatlvely greater cubical dimension.

10. The method of making castings having irregular'but relatively massive peripheries, said method, comprising, pouring the molten metal into a mold, filling a riser portion of the mold cavity extending above and radially connecting with the, portions of the mold of largest cubical content, rotating the mold with the axis of rotation disposed through I the riser of metal, whereby the molten metal is forced downwardly and outwardly to the portions of the mold of largest cubical content.

In witness whereof, I hereunto subscribe my name.

ELMER S, SAWTELLE.

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