US662561A - Mold for casting rings. - Google Patents

Description

' No. 662,56l. Patented Nov. 27, IQOOL W. H. FORD.

MOLD FOR CASTING RINGS.

' led (Application fl Feb. 23, 1900.]

' '(No Model.)

W s-see.- Mewv'on Wfl%i williammfi UNITE STATES a'rnn'r FFICEQ WILLIAM II. FORD, OF LOWELL, MASSACHUSETTS, ASSIGNOR OF ONE-HALF TO CYRUS W. RUSSELL, OF SAME PLACE.

' MOLD FOR CASTING RINGS.

SPECIFICATION forming part of Letters Patent No. 662,561, dated November 27, 1900.

Application filed February 23, 1900. Serial No. 6,150. (No model.)

To (LZZ whom it may concern.-

Be it known that 1, WILLIAM H. FORD, a citizen of the United States, and a resident of Lowell, county of'Middlesex, and State of Massachusetts, have invented an Improvement in Molds for Casting Rings, of which the following description, in connection with the accompanying drawings, is a specification, like numerals on the drawings representing like parts.

This invention relates to molds for casting annular articles, such as finger and watch rings.

My invention consists of a mold made from charcoal in its natural state in contradistinction to a mold containing comminuted charcoal with a binding material.

In my experiments aiming at the casting of rings in precious metal I discovered that I could not cast a practical ring in a sand or in a metal mold or in any other than a cut mold composed wholly of charcoal, for in the use of other material than charcoal the metal entering the mold-space acting against the mold material cools the fluid metal too rapidly, so that the air trapped in the mold-cavity by the incoming metal in its passage through the latter leaves a porous casting or a casting presenting blow holes, and frequently air is so trapped in the mold that the rapidly-cooling metal fails to contact properly with the surface of the mold-cavity, and a pit is left in the casting which destroys the same. To cast a ring practically, the mold used must be capable of having discharged from it a casting presenting the exact size indicated by the mold to determine finger size, and also the ring must show the exact pennyweight desired, and hence the casting must present a surface which finishes to substantially the required finger size and free from blow-holes, for it will be understood that if the casting presents a rough or pitted surface it must be filed or cut away to present a smooth surface, and this filing or dressing changes not only the finger size, but also the pennyweight.

In casting fluid metal in a charcoal mold I find that the charcoal constituting the interior wall of the mold when met by the fluid metal immediately becomes, owing to its na ture, nearly or substantially as hot as the metal, and consequently the cooling of the metal is so far retarded that the air in the mold, all of which for the production of a practical casting should be displaced, by the metal coming into the mold and which must fully fill the mold and contact closely with all parts thereof, said air readily passing through the fluid metal and issuing from the pouring-opening of the mold, the metal closing behind the passage-ways made in it by 'the escaping air, leaving a solid casting free from blow-holes, and inasmuch as the faces of the walls of the mold are smooth and left so by cutting the mold-groove in the charcoal the face of the casting is so smooth that little, if any, metal needs to be removed when finishing the ring to a true surface defined by the mold-cavity.

The entire charcoal mold acts uniformly alike in all parts of its surface on all parts of the fluid metal, and the mass of metal cools slowly, but uniformly, in a Way that it will not cool if other material than charcoal meets the metal.

In practice the metal cast in a charcoal mold does not commence to cool until after all air has been excluded from the moldcavity either by its passage through the fluid metal or otherwise, and thereafter after the metal has cooled sufficlently to retain the shape required by the mold the mold is separated and the ring is removed, this being done while the metal is yet very hot. If the metal is permitted to cool too much in the mold, it in its shrinking, due to cooling, hugs the core so closely that the ring cannot be removed without touching the core.

In the drawings, wherein the invention is shown in one embodiment thereof, Figures 1 and 2 are face views of the mold-halves or duplicate sections. Fig. 3 is a longitudinal central section of the mold in its assembled condition, showing a finger-ring therein. Fig. 4: is a plan view of said mold. Fig. 5 is a perspective View of the ring as it is taken from the mold.

I wish to state at this point that so far as I am aware I am the first to employ charcoal in its natural state as a mold for casting and which after many experiments I have adopted as the only possible way for securing an acceptable merchantable article, and hence I shall broadly claim this as one of the important features of my invention.

The mold may be of any convenient shape. It is denoted by M, and it is .represented (see Fig. 3) as being of rectangular or block form and as consisting of'two substantially duplicate sections or halves, as 12 and 13.

The mold has at or near its center a circular mold space or groove, as 14, which is cut therein and into which the molten metal is poured through the opening 15, intersecting said mold-space. The pouring-opening 15 is shown as tapered, its smallest end being next the mold-space, and it may be formed in the respective mold-halves.

The mold contains a core, preferably of charcoal, of which the mold is made. Said core defines the internal diameter of the ring and is cylindrical, the molten metal entering between the peripheryof the same and the wall of the mold-space, and the distance between these parts defines the thickness of the ring.

For simplicity and cheapness I cut in the adjacent faces of two pieces of charcoal, each constituting a mold section, an annular groove, the faces of the pieces having previously been dressed flat, thus forming a cut mold presenting a mold-space having a central cylindrical core 16, each mold-section containing integral therewith a half of the core.

In casting a ring the flat faces of the respective mold-sections and the ends of the cores are placed against each other, with the complemental sections of the groove, core, and pouring-opening in registration, and in this condition to insure the proper alinement of the grooves I may employa centering-pin, as 18, it being passed through openings 19 and 20, located centrally with relation to the core. The mold thus assembled, as shown in Fig. 3, will then be put in position with the pouringopening up, and the molten metal will then be supplied to the mold through the pouringopening, it entering the mold-space. During the pouring I preferably cant or tip the mold slightly, so that the molten metal at first runs down at one side of the mold space or groove, thereby forcing the air up the other side of said mold-space and out the pouring-opening; but when the mold-space and the pouringopening are nearly filled there remains a small percentage of very hot air in the mold space. The interior of the charcoal mold acted upon by the liquid metal becomes instantly heated to a very high temperature the moment the molten metal is introduced in the mold and being very hot the mold acts to retard the sudden cooling of the metal, as customary with other molds, and consequently the metal remains in its fluid condition for a space of time which will permit the passage through it of the air in the mold, the metal after the passage of air through it immediately assuming its original condition, leaving a solid body free from blow-holes, so that the ring when removed from the mold will be found, as shown at 22 in Fig. 5, with a finish that needs but the minimum of dressing to finish it after removing the slight projection 23, formed by the metal lying in the pouringopening, said projection being cut off by a suitable tool. When the metal in the ring (all the air having escaped from the mold) has cooled sufficiently, the parts of the mold may be separated by removing the centeringpin 18 and the ring removed before the casting cools to such an extent as to hug the core destructibly.

Not only does a charcoal mold possess the advantages pointed out hereinbefore, but it may be used many times and may be produced at a comparatively small cost, and such molds may be made by the use of an apparatus such as described in an application, Serial No. 703,540, filed by me on the 27th day of January, 1899. v

- Having described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. A mold for casting, consisting of a block of charcoal in its natural state having a moldcavity therein, a core also of charcoal within the cavity and integral with the mold-block.

2. A mold for casting consisting of a block of charcoal in its natural state, said mold being formed in two parts each havinga cavity and being provided with a core formed integral therewith.

3. A mold for casting consisting of a plurality of sections each section formed of a block of charcoal in its natural state having annular grooves cut therein and adapted to register.

4. A mold for casting consisting of a block of charcoal in its natural state in two substantially similar parts, each part having a flat face and each face having an annular groove forming thereby an integral core part, said grooves being adapted to register.

5. A mold for casting consisting of a block of charcoal in its natural state formed in a pin rality of sections having cut grooves adapted to register, said sections being formed with an integral core part and a centering-hole.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILLIAM H. FORD.

Witnesses:

Gno. W. GREGORY, MABEL PARTELOW.

IIO

Images