US1640843A

US1640843A - Mold for casting metals

Info

Publication number: US1640843A
Application number: US751657A
Authority: US
Inventors: Charles E Magill
Original assignee: Aluminum Company of America
Current assignee: Howmet Aerospace Inc
Priority date: 1924-11-22
Filing date: 1924-11-22
Publication date: 1927-08-30
Anticipated expiration: 1944-08-30

Description

1,640,84 Aug. 30, 1927. a E MAGILL 3 MOLD FOR CASTING METALS Filed Nov. 22, 1924 2 Sheets-Sheet l INVENTOR A ORNEY Au v 30, 1927.

C. E. MAGILL MOLD FOR CASTING METALS Filed Nov. 22, 1924 2 Sheets- Sheet 2 mam-um INVENTORI r I AQRNt-ZW Patented Aug. 30, 1927.

UNITED STATES PATENT OFFICE.

CHARLES E. MAGILL, 0F CLEVELAND, OHIO, ASSIGNOR TO THE ALUMINUM COMPANY OF AMERICA,

01 CLEVELAND, OHIO, A CORPORATION.

MOLD FOB CASTING METALS.

Application filed November 22, 1924. Serial No. 751,657.

This invention relates to composite molds for casting metallic articles particularly molds comprising a cope, and a drag in which a major part of the casting is formed.

It also relates to a mold for casting met-- als comprising a drag composed principally of granular material in which a major part of the casting is formed, and a cope composed principally of metal.

The ordinary sand molds comprising a drag and a cope, when employed for fairly large castings the major part of which are formed in the drag, are not capable of the highest degree of etlicient operation due to various factors, including the necessity of having separate molding'machines'for forming the drags and copes separately, together with other apparatus. such as cranes etc., to manipulate such machines and handle the material for use therewith. Furthermore, with sand copes many castings are defective because of cope drops, that is, sand from the cope dropping into the casting cavity before or during the casting operation.

I have, however, by my invention pro-vided a mold in which all danger of cope drops is eliminated and which can be operated much more rapidly than the molds now in use and with considerably less labor, material and equipment, thereby greatly decreasing the present cost to manufacturer. One important saving is in labor previously required in making copes while another saving is in removing all restraint on the molding of the drags due to the slower molding of the copes. It will be understood that the drag molding is faster than the cope molding and that since the drags and copes must move along together. the speed of cope molding determines the speed of drag molding.

, At the same time my improved mold produces castings possessing properties heretofore unobtainable in the ordinary molds except by the use of numbers of metal chills inserted in the cope during the molding operation. v

In the drawings accompanying this specification and forming a part thereof:

Fig. 1 is a top plan view of a mold constructed in accordance with my invention, the outlines of the casting being indicated in dotted lines.

Fig. 2 is a vertical, longitudinal cross section taken on line 22 of Fig. 1.

Fig. 3 is a vertical, transverse cross section taken on line 3-3 of Fig. 1, and

Fig. 4 is a bottom plan view of a modified form of cope.

In the drawings Numeral 1 designates a flask for the drag or bottom portion of a mold, the flask 1 consisting of a bottom plate 2 and four upri ht side walls 3 within which sand 4 or 0t er similar molding material may be packed and formed with a cavity 5 for a major part or all of an article 6, in this case a crank case for an automobile engine. The drag also carries cores 7 suitabl supported within the casting cavity 5 to orm certain walls of the cavity against which the molten metal may be cast in forming. the casting 6 as will be understood by those skilled in the art. The drag, including the above described parts, is substantially the same as the drags now in common use in the sand foundry industry.

The cope 8 consists of a thin metal plate of suitable size to rest on the top of and be supported by the upright walls 3 of flask l and having end extensions 8 to serve as supports by which it may be carried. It is provided with a plurality of perforations extending therethrough and communicating with the drag at points immediately above or adjacent to the casting cavity when assembled with the drag. Certain of these openings, indicated at 9, preferably lead directly into the casting cavity while opening 10 leads into the casting cavity and communicates with the casting cavity through a runner 11 and gates 12 leading to various parts of the casting cavity, as the nature of the casting necessitates. Each of the openings 9 and 10 has a liner composed of refractory heat insulating material toprevent contact of the molten metal with the sides of the openings. These liners which are indicated at 13 consist pref drag at one side of the for the casting. Although openings 9 are here employed as risers and opening as a pouring gate, it will be understood that molten metal in some instances may be poured directly into the casting cavity through one or more openings 9, if desired. It will be noted that cope 8 forms certain walls of the casting cavity, as more clearly indicated in Fig. 3. IVhere the cope thus constitutes walls of the casting cavity it acts to expedite chilling of -the molten metal coming into contact therewith, and thereby tends to produce dense, nonporous cast metal which at such points of contact is particularly advantageous when such metals as aluminum 'alloys are being cast. It is desirable, however, to maintain large bodies of molten metal out of contact with the cope except at places where a chilling elfect is desired, since the molten metal is unduly in cope 8 to receive this cover or it may supported in recesses in the mold material 4.

In operating a mold of my construction, J. pattern (not shown) is laced on a plate (not shown) within the ask 1, sand 4. is rammed around the pattern after which the flask is turned over into the position shown in Fig. 2, the pattern extracted and the cores 7 fittedinto place. Runner 11 and gate 12 are cut in the sand 2 and cover 14 placed thereover. Then cope 8 with liners 13 in the openings 9 and 10 is placed on flask 1. Molten metal is then poured through opening 10 into runner 11 and feeds into casting cavity 5 through gates 12 filling the cavity and rising into liners 13 above the cope. After the molten metal has solidified the liners 13 and cope 8 are removed and the.

gate and riser metal which solidifies in the.

liners 13.

In Fig. 4 I have shown a slightly modified form of my invention where the cope 8 has cores secured to its under face. In this particular case the cope is for use in making crank case castings for automobile engines, the cores 15 being provided for coring out the crank shaft bosses. When the cope is provided with cores attached thereto any danger of misalignment of these cores is avoided as contrasted with the use of separate sand or metal cores. as shown in Fig. 2.

Although I have shown substantially square liners l3 and substantially square holes 9 and 10 in the cope, I may make the holes 9 and 10 round and employ therewith round liners. Such liners may be readily fitted into the openings 9 and 10 with close fitting engagement by having the outer surfaces of the liners slightly larger in diameter than the corresponding diameter of the openings 9 and 10, so that when the liners are inserted in the opening and rotated back and forth slightly, they will seat on the cope and have close fitting engagement with the walls of the, openings. But whatever the cross section of the liners 13 may be, it is desiri able that they engage closely with the side walls of the openings of which they constitute the liners. In case the liners do not fit closely to the cope, molten metal from the casting cavity may form fins between the cope and liners which act as anchors when the casting shrinks in cooling and may cause breakage of the casting intermediate such anchors. For example, if such fins were formed around the liners at either end of thev casting 6 (shown herein) the ends of the castings would be more or less fixed or anchored and as the casting shrinks in cooling a crack or cracks across the intermediate portion, of the casting might result;

With close contact between the liners and cope no such danger exists.

Having thus described my invention so that those skilled in the art may be enabled to practice the same, what I desire to secure by Letters- Patent is defined in what is claimed, it being understood that changes not involving invention may be made in the details hereinabove shown and described, without departing from the spirit and scope of my invention.

What is claimed is:

1. A mold for casting metallic articles comprising a drag provided with a casting cavity for a major portion of the article to be cast, and a cope composed of metal and provided with a plurality of perforations in which molten metal may solidify, the perforations extending through the cope-and communicating with the said casting cavity, the cope being removablefrom and without contacting with solidified metal in the perforations.

2. A mold for casting metallic articles comprising a drag provided with a casting cavity for a major portion of the article to be cast and with cores in. the said cavity. the said drag. and cores being composed of granular material, and a cope composed of metal and provided with a plurality of perforations in which molten metal may solidify, the perforations extending through the cope and communicating with the said casting cavity, the cope being removable from and without contacting with solidified metal in the perforations.

3. A mold for casting metallic articles comprising a drag composed of granular material and provided with a casting cavity for a major portion ofthe article to be cast, and a cope composed of metal and provided with a plurality of-perforations in which molten metal may solidify, the perforations extending through the cope and communicating with the said casting cavity, the cope being removable from and without contacting with solidified metal in the perforations.

4. The combination set forth in claim 1 in which each perforation of the cope is provided With a liner composed of refractory material.

5. The combination set forth in claim 1 in which each perforation in the cope is provided with a refractory liner extending through and well above the cope.

6. In a mold for casting metallic articles the combination of a flask, granular material in the flask provided-with a casting cavity, COIKS in thecasti'ng cavity, a thin metal cope on the flask forming top walls of the casting cavity and provided with perforations in which molten metal may solidify, the perforations extending through the cope and communicating with the casting cavity, the

cope being removable from and without contacting with solidified metal in the perforations.

7. In a mold for casting metallic articles, the combination of a flask, granular material in the flask provided with communicating open topped casting and runner cavities, a thin metal cope on the flask constituting a cover for the said casting cavity, against which molten metal is cast, and a heat insulating'cover for the said runner cavity between the runner and the cope, the said cope having a plurality of perforations for a pouring gate and risers extending therethrough and communicating with the said casting and runner cavities.

8. In a mold for casting metallic articles, the combination of a flask, granular material in the flask provided with a casting cavity, core-s in the casting cavity, a thin metal cope on the flask forming top walls of the casting cavity and provided with perforations, liners of refractory material in the said perforations having close fitting contact with the sides of the perforations; the said perforations in the cope being larger than the greatest cross sectional dimensions of metal solidifying therein. I

9. In a mold for casting metallic articles, the combination of a flask, granular material in the flask provided with communicating open topped casting and runner cavities. a thin metal cope on the flask constituting a cover for the said casting cavity, and a heat insulating cover for the said runner cavity between the runner and the cope, the said cope having a plurality of perforations for a pouring gate and risers extending therethrough and communicating with the said casting and runner cavities and refractory liners for the said perforations extending through the cope and well thereabove.

10. The combination set forth in claim 9 in which the said liners have close fitting engagement with the cope in the said perforations.

11. A mold for casting metallic articles of considerable bulk and surface areas, comprising a drag composed of green sand and provided with an open topped casting'cavity for a major portion of the article to be cast, sand cores in the said cavity in the drag, a plate like cope composed principally of metal constituting a closure for the casting cavity against which the molten metal is cast and provided with perforations for a metal pouring gate and for risers, and heat insulating liners for the said perforations extending through the cope and well thereabove, the cross sectional dimensions of metal solidifying in the gate and risers being smaller than the said perforations in the cope.

12. A mold for casting metallic articles of considerable bulk and surface area,'com prising a drag composed of green sand and provided with an open topped casting cav- 1ty for a major portion of the articles to be cast, and also provided with an open topped runner at one side of and communicating with the said casting cavity, sand cores in the said cavity in the drag, a plate like cope composed principally of metal constituting a closure for the casting cavity against which the molten metal is cast and pro- .vided with a perforation opening into the said runner and a plurality of perforations opening into the casting cavity, a heat insulating cover for the said runner, and heat insula-tlng liners for the said perforations extending through the cope and Well thereabove.

13. A cope for a mold comprising a thin metal plate provided with a plurality of perforations extending therethrough and heat insulating liners having close fitting engagement in the perforations and extending through the cope and well thereabove, the passages formed by the liners being of smaller cross sectional dimensions than the perforations in the cope.

14. A cope for a mold comprising a thin metal plate provided with gate and riser perforations therethrough, liners for the said perforations composed of frangible.

material and forming passages through the perforations smaller in the cope, surface of the cope.

than the perforations and a core secured to the under- 15. A cope for a mold comprising a thin 5 metal plate provided with perforations therethrough,

periorations compose ate and riser iners for the d of frangible matesignature.

CHARLES E. MAGILL.