FIELD OF THE INVENTION

The present invention relates to metal ingots, and more particularly to gold ingots and a method of manufacturing same into a novel shape appropriate to be worn as jewellery.

BACKGROUND OF THE INVENTION

An ingot is a mass of metal (often tin, steel, gold, or silver) that has been cast into a bar, block, mold, sheet, plate, or the like, of a certain size and shape that is convenient for storage and transport purposes, or for working into another semi-finished or finished product. In this respect, ingots are typically rectangular in shape, which allows for stacking.

The problem with the typical rectangular shape, however, is that although it may be convenient for storage and transport by commercial means, it is not convenient to be worn as jewelry by individuals in the normal course.

The present invention seeks to overcome problems associated with gold jewelry in the traditional shape and size, by providing an ingot that allows for ease of personal transport and wearability.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a gold ingot comprising: a generally obround body having, a rounded spherical surface on each opposing end of said obround body, four curvilinear longitudinal edges along a main axis of said obround body, four flat longitudinal surfaces along the main axis of said obround body, and a circular void that extends through two opposing surfaces of said four flat longitudinal surfaces, said circular void located between centers of radii located on the flat longitudinal surfaces adjacent the rounded spherical surface on each opposing end of said obround body.

In another aspect, the present invention provides a gold ingot comprising: a generally obround body having, a rounded spherical surface on each opposing end of said obround body, four curvilinear longitudinal edges along a main axis of said obround body, four flat longitudinal surfaces along the main axis of said obround body, and a circular void that extends through two opposing surfaces of said four curvilinear longitudinal surfaces, said circular void located between centers of radii located on the curvilinear longitudinal surfaces adjacent the rounded spherical surface on each opposing end of said obround body.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a perspective view of one embodiment of an INGOT in accordance with the present invention;

FIG. 2a is a front elevational view of the embodiment shown in FIG. 1, the rear elevational view being identical;

FIG. 2b is a representation of the INGOT shown in FIG. 2a, with example measurements that would assist in forming a one-Troy-ounce ingot;

FIG. 3a is a left side elevational view of the embodiment shown in FIG. 1, the right side elevational view being identical;

FIG. 3b is a representation of the INGOT shown in FIG. 3a, with example measurements that would assist in forming a one-Troy-ounce ingot;

FIG. 4a is a top plan view of the embodiment shown in FIG. 1, the bottom plan view being identical;

FIG. 4b is a representation of the INGOT shown in FIG. 4a, with example measurements that would assist in forming a one-Troy-ounce ingot; and

FIG. 5 is a schematic representation of a hot chamber machine used in an exemplary method to produce an ingot of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, the present invention involves the manufacture of a one-Troy-ounce gold bullion bar/ingot 100 having a novel shape and features that makes it more akin to jewellery than a bullion bar made primarily for commercial storage. However, unlike jewellery, which is normally alloyed, the ingot 100 of the present invention consists of 24 k gold (99.99% pure and unalloyed); and, unlike a coin or bullion bar, which are the only forms of unalloyed gold normally available, the ingot 100 of the present invention can be carried on a chain or cord around an individual's neck or wrist for ease of transport.

Moreover, with particular reference to FIGS. 1, 2a, 3a, and 4a, the ingot 100 of the present invention is generally obround and shaped to:

- a. minimize wear and prevent irritation, if worn, by having smooth surfaces, namely rounded spherical ends 110 and curvilinear longitudinal edges 120, with no sharp or pointed corners or edges;
- b. prevent rolling (and therefore potential loss) if dropped, by having flat longitudinal surfaces 130 on 4 sides; and
- c. accommodate markings on its flat longitudinal surfaces 130 to indicate assayer/producer, weight, fineness, and serial number, as desired.

With reference to FIGS. 1, 2a, and 2b, wearability is facilitated by a hole or void 140 about 2 mm in diameter, through which a chain, cord, or the like can pass to allow the ingot 100 to be worn around an individual's neck or wrist. Depending on customer preference, this hole or void 140 may be located at any point along the main axis of the ingot 100, preferably on a flat longitudinal surface 130 thereof between the centers of radii 150 adjacent the rounded spherical ends 110. For depiction purposes, the hole or void 140 is shown in the Figures centered on the ingot 100 between the centers of radii 150.

Various exemplary measurements are provided in FIGS. 2b, 3b, and 4b that enable the creation of a one-Troy-ounce gold ingot 100 of the present invention. However, a person skilled in the art would be able to produce an ingot 100 of different size/weight as desired.

A person skilled in the art would appreciate that various known methods could potentially be used to form an ingot 100 of the present invention. For instance, the skilled person could consider use of a traditional casting method, a vacuum casting method, direct fusion, or a hot chamber die casting method, among other methods.

An exemplary method of manufacturing an ingot 100 of the present invention involves the use of a modified hot chamber die casting method as described hereinafter.

In order to manufacture the ingot 100, a 3-dimensional definition is created using CAD (Computer-Aided-Design) software, and a steel wax-molding die is created from the CAD definition.

From this a “positive” replica of the ingot is molded in wax or polymer using the wax-molding die. A hole is drilled into the injection-molded wax “positive” to accommodate a core, and a core is inserted into the wax “positive” to form the necessary hole/void in the ingot.

A “negative” of the ingot is then formed around the “positive” wax impression. This “negative” is created using an appropriate sand type and molding resin in a forming box or flask. The “negative” sand mold is hardened through chemical or heat processes.

Two holes are subsequently drilled in the top surface of the hardened sand mold. These holes fully penetrate the upper mold wall and may extend into the wax somewhat. Molten gold is injected into the hardened sand mold through one hole; the other hole is a vent.

Gold injection is achieved via piston to inject the exact mass required. With reference to FIG. 5, a pot 200 holds molten gold heated by a burner 210. Within the molten gold pool is a gooseneck 220. The gooseneck is a device to accurately draw in molten metal and to subsequently press out through a nozzle 230 a fixed quantity of molten metal. It includes a power cylinder 240, a plunger 250, a plunger cylinder 260 and an intake port 270.

Upon retraction of the plunger 250 upwards, a vacuum is created within the plunger cylinder 260, and molten metal from the pot 200 is drawn into the plunger cylinder 260. Next, the power cylinder 240 pushes the plunger 250 downward. This blocks the intake port 270 to prevent molten metal from returning to the pot 200. Molten metal is instead forced through the gooseneck 220 to the nozzle 230. The nozzle 230 is aligned with a sand mold (not shown) so as to accept a 1-Troy-Ounce quantity of molten metal. Upon subsequent cooling, the sand mold is broken away from the molded ingot and discarded.

The core is then removed from the molded ingot, and sprues from the pour hole and vent hole are trimmed. The injection (sprue) surface is smoothed mechanically, any desired/necessary marks are stamped on the four flat longitudinal surfaces 130 of the ingot, and the ingot is polished.

This method is novel in that the molding of the finished ingot is a combination of two methods: 1) the traditional lost-wax method of molding; and 2) the high-pressure die-casting method. Since the melt is injected directly into the sand mold, with direct venting from the sand mold, the melt injection in this case does not require high pressure—it is an atmospheric-pressure process. However, the method utilizes mechanical injection at low pressure in order to: 1) accurately meter the quantity of melt injected; 2) speed the melt flow into the mold; and 3) ensure the mold cavity is completely filled. An excess quantity of melt is injected to ensure complete fill of the mold cavity. The excess is removed afterward.