SK280980B6 - Bimetallic blank for coins - Google Patents

Abstract

The invention relates to a bimetallic blank for coins, medallions, tokens, gaming chips and the like, consisting of an inner disc (1) of a first metal or of a metal alloy which is pressed into the central aperture of an outer ring (2) of a second metal or of a second metal alloy, the disc (1) being provided with obliquely extending indentations (5) on its outer edge.

Description

Technical field

The invention relates to a two-piece blank for coins, medals, tokens, tokens and the like, comprising an inner roll of a first metal or a metal alloy which is pressed into a central opening of the outer ring of a second metal or a second metal alloy.

BACKGROUND OF THE INVENTION

In the past, the coins were mainly made of one piece of solid metal of uniform composition. In addition, coins were also made from various metals and metal alloys. These are predominantly laminated sandwich materials which are produced, for example, by cladding, rolling of a brass-coated steel core. Rather, such material connections were increasingly used to produce coins, which consisted of an inner disk of one metal around which an outer ring of another metal or another metal alloy was placed. For example, the Italian 500-liter coin consists of a gold-colored copper alloy. Concentrically around this inner disc is an outer ring made of blue-glittering silver-gray chrome steel. High-speed embossing machines according to today's machine technology, by means of which these load-bearing material joints are produced even in the case of a large number of pieces, require special attention in the manufacture of the components of such concentric material joint. Therefore, special precautions are necessary in order to achieve a fitting connection of the inner disc and the outer ring, which would adhere well to each other.

It is proposed in US-A-3 499 739 that the outer ring be selected somewhat thicker than the inner disc. As a result, the outer ring is to be pushed over the edges of the inner disc during the pressing, and thus a positive fit of the disc-ring connection is achieved. JP-A-58-3743 contains a proposal to provide an inner disk or alternatively an outer ring with a peripheral edge groove. For coupling, the two components are inserted into each other, and by means of a special tool, the material of the inner disc is pressed into a groove in the outer ring or vice versa.

It is known from EP-A-0 080 437 that the inner edge of the outer ring is wedge-shaped and the inner disc is provided with an edge squeezed roll. In the molding, the material from this wall can then flow through the tapered inner edge of the outer ring. At the same time, a plurality of protruding teeth are also disposed on the inner edge of the outer ring, which are to be pressed into the inner disc during shifting. this eliminates the possibility of rotating the outer ring and the inner disc relative to each other after compression.

EP-A-0 160 343 understands this idea with a very similarly formed outer ring. A pile is introduced into the outer ring of the coin known from EP-A-0 280 615 and then plastically formed into an inner roll. In EP-A-0 415 892, the inner edge of the outer ring is provided with a discontinuous circumferential groove, into which the material of the inner disc flows during pressing.

While teaching according to US-A-3 499 739 has proved to be inadequate for practical use and teaching according to said JP-A requires a special connection tool, teaching according to EP-A-0 080 437, 0 160 343 and 0 415 892 the lack that a complicated geometric shape must be given to the inside of the ring.

SUMMARY OF THE INVENTION

Unexpectedly, it has now been shown that by simply executing and simple shaping the outer edge of the inner disc, the twisting of both parts and the falling off of the inner disc from the outer ring after pressing are safely prevented. For this purpose, it is sufficient if the outer edge of the inner disc is provided with recesses running in an obliquely directed arrangement. These recesses can also be designed as a spiral groove. This facilitates the flow of material of the outer panel into the recess of the inner panel.

In a further embodiment of the invention, this is solved in such a way that the electrical conductivity of the outer ring and the inner disk of the concentric coin connection of the materials is very different. This is best achieved by using a copper coin material with a specific electrical resistance of not more than 25 μΩ for an electrically conductive part. cm. For an electrically poorly conductive part, chrome steel or chrome-nickel steel with a specific electrical resistance of at least 70 μΩ should be selected. cm. The electrically inferior conductive part can also be a laminated ferritic or austenitic steel joint. This achieves the following:

Today's electronic coin tester uses the principle of electromagnetic interaction between different frequency electromagnetic fields and coin metals in various ways. When passing coins through the coil system of coin tester, characteristic double signals can be achieved if the significantly better conductive part of the material connection forms the outer ring or alternatively a single signal with the characteristic form of the curve, when the significantly better conductive part forms the inner disc.

Overview of the figures in the drawing

The invention is explained by means of the drawings. Individual Figs. FIG. 1 is a perspective view of the outer ring of a coin; FIG. 2 shows a perspective view of an inner disk in one embodiment, FIG. 3 in an embodiment that is modified from that of FIG. Second

DETAILED DESCRIPTION OF THE INVENTION

The coin consists of the outer ring 2 of FIG. 1, which has a central opening whose contour corresponds to that of the inner disk 1 of FIG. 2 or 3 such that the inner disk 1 is connected by pressing into the central opening of the outer ring 2 by force contact with the outer ring 2.

In order to improve the coherence of the two parts 1, 2, according to the invention, a plurality of inclined recesses 5 are formed in the outer edge 4 of the inner disc 1 (FIG. 2). 3, the recesses are connected in the form of a spiral groove 5a, which winds around the outer edge 4 of the inner disc 1. In these recesses 5, 5a the material flows into the recesses 1, 2. As a result of this, besides the force contact, the form-fitting connection of the parts 1, 2 also arises.

Due to the inclined position of the recesses 5, 5a according to the invention, the material inflow is greatly facilitated when the two parts 1,2 are pressed together, because the recesses 5,5a are slowly filled with the material of the second part, in which the recesses are not.

Claims (4)

PATENT CLAIMS A two-part semi-finished product for coins, medals, tokens, gambling tokens and the like, consisting of an inner disk of a first metal or a metal alloy, characterized in that the inner disk (1) has an obliquely opposed edge (4) recess (5). Semi-finished product according to claim 1, characterized in that the inclined recesses form a spiral groove (5a) extending around the outer edge of the inner disc (1). Semi-finished product according to claim 1 or 2, characterized in that the materials of the inner disk (1) and the outer ring (2) differ by at least 45 μ Ω cm in their specific electrical resistance. Semi-finished product according to claim 3, characterized in that the electrically inferior conductive part consists of chromium steel or chromium-nickel steel or a laminated connection of austenitic or ferritic stainless steel.