US1410777A

US1410777A - Mold fob

Info

Publication number: US1410777A
Authority: US
Publication date: 1922-03-28
Anticipated expiration: 1939-03-28

Description

F. E. THOMES.

MOLD FOR MAKING METAL CASTINGS. v APPLICATION FILED JULYZI, 1919. RENEWED JULY 25.1921. 1,410,777.

Patented Mar. 28, 1922. Fly. 3.

UNITED STATES FATENT FOEFEQE.

FRANK E. THOMES, OF PORTLAND, MAINE.

MOLD FOR MAKING METAL GASTIN'GS.

To all whom it may concern:

Be it known that I, FRANK E. THoMEs, a citizen of the United States, residing at Portland, in the county of Cumberland and State of Maine, have invented certain new and useful Improvements in Molds for Making Metal Castings, of which the following is a specification.

My invention relates to molds for making metal castings and it relates particularly to the application of the principles underlying the invention shown in my application No. 203,840, filed Nov. 24, 1917, to various forms of castings and particularly to the making castings of steel and other metals having such shrinkage.

My original invention was based on the idea of feeding the casting from a preheated shrink head or chamber, the preheating being accomplished by pouring the casting through the shrink head to maintain the feeding metal at a high degree of heat and fluidity.

In making steel castings, there are many forms which it is diflicult to make without shrink holes and cracks on account of the great shrinkage which takes place in the metal as it cools and consolidates.

I have found that the mold described and claimed in my said application is well adapted for gating and feeding many forms of steel castings and particularly those which have been diflicult to make under the old method. There are various forms, however, which I have found to require special modi fications of my original invention and my aim has been to adapt the principles of that invention to substantially all forms of casting which may be met with the foundry practice.

In the mold described in my said application, the shrink head, or feeding chamber, received its metal from a skim gate which enclosed and protected the upper end of the shrink head and the metal was discharged laterally from the shrink head intothe matrix, the shrink head being located as closely as possible at the side of the matrix.

In applying this-mold to castings of different kinds, I have found it desirable to make various changes and modifications to Specification of Letters Patent. Patented 1 28 1922 Application filed. July 21, 1919, Serial No. 312,381.

Renewed July 25, 1921. Serial No. 487,516.

suit th peculiar characteristics of the castings and particularly in adapting it to castings having heavy sections difficult to feed.

I have found, for instance, that in the case of pulleys and gears having hubs of heavy section, it is desirable to enter the matrix from the top rather than from the side as in the case of my original mold.

If the shrink head, or feeding chamber, were to be located directly over the heav section and fed down through, the hydrostatic head and velocity of the metal as it entered the matrix would cause an elongated body of very hot metal to penetrate vertically into the heavy section of the matrix and when the casting cooled cracks and shrink holes would be very likely to result.

To overcome this defect and to adapt my shrink head to top feeding and pouring, I arrange the shrink head above and at one side of the hub or other heavy section and arrange the outlet to the shrink head so that it opens laterally and thence downwardly into the heavy section of the casting. In this manner the metal, instead of pouring directly downward, overflows into the heavy section of the casting with a gentle motion and tends to make an even distribution of the melted metal throughout the matrix.

In some instances where a casting is relatively deep, I have found it advantageous to form a runner on the lower end of my shrink head and to connect the runner with the lower portion of the matrix so that the latter will be under-poured while laterally connecting the shrink head with the upper portion of the casting-to provide for the effective feeding. Where in a deep casting there is a heavy section above and below, I feed both the upper and lower portions with a shrink head for each, connecting the two shrink heads by a runner so that all parts are effectively poured and fed.

A further improvement in my mold I secure by forming a small indicating passage extending from the matrix to the top of the cope and terminating substantially at the same level as the top of the shrink head. By carefully watching the indicating opening the foundryman can tell when the shrink head is full although the latter is out of sight, and thus prevent the metal from overflowing irom the top of the shrink head and filling the runners and other passages through which the metal enters it.

111 the accompanying drawing, I have illustrated several of the modifications and improvements above referred to and which constitute my present invention.

Referring to the drawing:

Fig. 1 is a plan view of my mold formed for top pouring of a heavy section,

Fig. 2 is a section on the line 11 of Fi 1,

ig. 3 is a plan view of a mold for deep castings showing a runner for under-pouring,

Fig. 4 is a sectionon the lin 22 of Fig. 2 and Fig. 5 is a central section of a mold adapted to making a deep casting with heavy sections above and below.

Similar reference numbers indicate similar parts in the drawing.

Referring to Figs. 1 and 2, 1 represents the cope and 2 the nowel, or drag, and 3 represents the matrix, which, in this instance, is formed for casting a gear with a heavy hub section.

The shrink head 4 is formed in the sand above and slightly at one side of the hub and connects with said hub by a passage 5 which leads first laterally and then downwardly into the hub portion of the matrix.

The lower end of the shrink head is hollowed out into a basin 6 slightly below the lateral outlet 5.

As the result of this construction, the metal first falls into the basin 6 through the pouring opening and gently overflows into the hub section of the matrix evenly distributing itself throughout the matrix and without any tendency to force a vertical stream of hot metal into the hub portion of the matrix.

The shrink head is fed through a pouring basin formed in a block of core material 7 which rests on the top of the cope.

-The basin proper consists of a conical opening 8 terminating at its lower end in a vertical cylindrical space 9. A horn sprue 10 extends from the'side of the opening 9 and enters the upper end of the shrink head 4.

Thus, when the stream of hot metal falls into the pouring chamber 8, as it often does from a considerable height, it overflows through the horn sprue 10 into the shrink head and again overflows from the shrink head into the matrix so that the harmful eifect of the hydrostatic head and the velocity of the stream of metal entering the matrix is entirely eliminated and the metal w thin the matrix approaches uniformity of temperature.

For the purpose of checking the pouri operation so that the pouring basin and its connection will not be filled, 1 form a small indicating passage 11 which extends from the upper portion of th matrix to an opening through the to of the cope, said opening being substantially of the same level as the top of the shrink head.

By watching the upper end of the indicating passage 11, the shrink head can be exactly filled without any overflow which may extend into any sprues or runners with which it may be connected.

Referring to Figs. 3 and 4, my invention is shown as applied to a relatively deep casting having a heavy section at the top, the mold in this case being formed for casting a heavy cylinder 12 with a flange or collar 13 at its upper end. The shrink head 14 is formed in thecope and opens laterally with a very short connection into the edge of the collar 13.

The casting is under-poured by means of a runner, or sprue, which leads from the lower portion of the shrink head 14 to the lower portion of the matrix. I As here shown, a vertical runner 15 leads from the bottom of the shrink head and connects at its lower end with a horizontal branch runner 16 which enters the bottom of the matrix, the casting'is poured by means of a pouring basin 17 having a horn sprue 18 similar to that shown in Fig. 2 and the sprue 18 is of substantially the same size as the runner 15.

In pouring the casting, the metal drops to the lower end of the shrink head and flows down through the runner 15 at substantially the same rate at which it enters the shrink head.

The result is that the casting is poured from the bottom upward and substantially no metal enters at the flange until the matrix is full and the metal passes in laterally from the shrink head. i I

As aresult of this construction of the mold. the metal all passes through 'the'shrink head preheating the same to a high degree and the metal. enters the matrix with very little current or disturbance thus tending to preserve a uniform temperature throughout the matrix and in this manner preventing voids and cracks;

As the shrinkage takes place in the casting, the metal from the shrink head flows in to compensate for the shrinkage, this being at a higher temperature and more liquid in consistency than any portion of the matrix.

An indicator opening 11 is formed in the cope in the same manner as shown in Fig. 2. Referring to Fig. 5, I have shown a modification adapted to a deep casting having a heavy section at the top and also at some point lower down in the casting.

The illustration isa mold formed for east- 1 ing a. lac-celled nozzle, or base, designed to form the lower end of a pulp digester which is a tall structure. formed of steel plates with a tapering lower end.

These castings are built to stand a very high pressure and great difficulty has been experienced hitherto in casting them without shrink cracks which greatly weakened the casting.

The matrix in Fig. 5 represents the casting which has a heavy annular section 19 at the upper end and a heavy annular section 20 between the two ends.

For the purpose of feeding this casting, I make use of a shrink head 21 located at the edge of the flange 19 and closely adjacent thereto with a second shrink head 22 closely adjacent to and connected with the annular section 20, the two shrink heads being connected by a runner 23.

The metal is poured through a pouring basin 24 similar to the pouring basin shown in Figs. 2 and l.

The metal enters the shrink head 21 thence passes through the runner 23, the shrink head 22 and thence into the matrix.

The matrix is gradually filled through the shrink head 22, the metal from the Shrink head '21 not entering until the top of the casting is reached.

The heavy sections 19 and 20 are fed during the shrinking period by the large body of very hot metal contained in shrink heads 21 and 22 which have been preheated by having all the molten metal mass through them and as a result the casting comes out free from shrink cracks or voids.

The modifications above described are all based on the same principle shown in my original application Serial No. 302,840, filed Nov. 24:, 1917 that is, by pouring the casting through a preheated shrink head and are designed to adapt the principle to castings of varying shape and size and particularly to apply it to those forms where it has been difficult or impossible to make sound steel castings without cracks and shrink holes.

I claim:

1. In a mold for making metal castings, the combination of a matrix, a shrink head above the level of said matrix having apouring opening and with a feeding passage leading laterally from said shrink head and thence downwardly into the upper portion of the matrix.

2. In a mold for making metal castings, the combination of a matrix, a shrink head communicating with said matrix, a pouring basin having a horn sprue leading from said pouring basin to said shrink head.

3. In a mold for making metal castings, the combination of a matrix, a shrink head above the level of said matrix having a passage leading laterally therefrom and thence downwardly into the upper portion of said matrix, a pouring basin above said shrink head having a horn sprue entering the said shrink head.

4:. In a mold for making metal castings, the combination of a matrix, a shrink head communicating therewith, a pouring opening communicating with said shrink head and an indicator opening extending from the matrix to the exterior of the top of the mold and at a point substantially at a level with the top of the shrink head.

5. In a mold for making metal castings, the combination of a matrix, a shrink head communicating therewith and having a pouring opening,'a runner entering the bottom of the shrink head and communicating with the lower portion of the matrix.

6. In a mold for making metal castings, the combination of a matrix, a shrink head connecting therewith and having a pouring opening, a runner entering the bottom of said shrink head and communicating with the lower portion of said matrix, the said runner and pouring opening being of sub stantially the same size whereby the matrix will be filled through the runner and fed through the shrink head.