US 3607147 A
Description (OCR text may contain errors)
United States Patent  References Cited Inventor Brian G. Harrison Drexel Hill, Pa. AppL No 858,689 UNITED STATES PATENTS Filed Sept. 17, 1969 2,782,498 2/1957 MUSllOVlC et al 29/497.5 patented Sept 21 1971 3,031,330 4/1962 l-lornrck 117/46 Assignee The Franklin Mint, Inc, 3,210,840 10/1965 Ulam 29/488 yeadon, Pm 3,261,724 7/1966 Ulam 148/115 3,462,827 8/1969 Winter 29/472.3 3,496,621 2/1970 Winter 29/] 83.5
.. Primary Examiner-L. Dewayne Rutledge Assistant ExaminerE. L Weise AttorneySeidel, Gouda and Goldhammer BIMETALLIC COIN 3 Clam 2 Draw"; ABSTRACT: A coin is disclosed having a middle layer of alu- U.S. Cl. 29/191, minum clad on its opposite major faces with stainless steel. 29/ 196.2 The aluminum layer has a thickness corresponding to to Int. Cl A44c 21/00 percent of the combined thickness of the three layers. The Field of Search 29/1962, color differential between the layers is minimal since all layers 191, 183.5, 40/27.5 have substantially the same light reflective properties.
PATENTEDSEPZ] |97| 147 FIG. 2
IN l/E N TOR BRIAN 6- HARRISON A TTORNEYS.
BIMETALLIC COIN This invention relates to a bimetallic coin which is light in weight, has good wear characteristics, and has a good feel. The thin layer of stainless steel is clad to the opposite surfaces of a layer of aluminum, typically by the application of heat and pressure. The aluminum layer has a thickness corresponding to 80 to 95 percent of the combined thickness of the three layers.
As used herein, the word aluminum is to be interpreted as including aluminum alloys. The stainless steel and aluminum layers have substantially the same light reflective properties whereby the color differential is nondistinctive and thereby unobjectionable. The coin is light in weight due primarily to the aluminum layer. As used herein, the word coin" is intended to encompass nonmonetary tokens, medallions, gambling chips, commemorative coins, etc.
It is an object of the present invention to provide a coin which has good wear characteristics, resists corrosion, is lighter in weight than most coinage, but nevertheless retains acceptable feel."
It is another object of the present invention to provide a coin which accomplishes the above-identified object by using a sandwich of aluminum and stainless steel.
it is another object of the present invention to provide a bimetallic coin wherein the layers thereof have substantially the same light reflective properties.
Other objects will appear hereinafter.
For the purpose of illustrating the invention, there is shown in the drawings a form which is presently preferred; it being understood, however, that this invention is not limited to the precise arrangements and instrumentalities shown.
FIG. 1 is a plan view of a coin in accordance with the present invention. 1
FIG. 2 is a sectional view taken along the line 22 in FIG. 1.
Referring to the drawing in detail, wherein like numerals indicate like elements, there is shown in FIG. 1 a coin designated generally as 10. The coin may have any commemorative figure or other configuration 12 applied to one surface thereof. The other surface of the coin may have a similar configuration or a different configuration 14 and/or explanatory wording.
The coin 10 is bimetallic and comprises a middle layer of aluminum, a top layer 18 of stainless steel, and a bottom layer of stainless steel. The layers 16-20 have substantially the same light reflective properties. Layer 16 has a thickness of between 80 and 95 percent of the combined thickness of all of the layers. Preferably, the layer 16 has a thickness of 90 percent of the combined thickness with each of the layers 18 and 20 having a thickness of approximately 5 percent of the combined thickness of the coin 10.
The layer 16 renders the coin 10 light in weight. The stain less steel layers 18 and 20 provide for good wear characteristics and provide the coin 10 with a good feel. The coin 10 preferably has a milled periphery 22. The milled periphery 22 helps to break up the light and render the interface between the layers difficult to discern, in view of the fact that the layers are substantially the same color.
The hardness of the stainless steel layers 18 and 20 is substantially higher than normal for coinage alloys. lndeed, the material used in the layers 18 and 20 would normally be uncoinable. The aluminum layer 16, however, allows for stretching and bending of the layers 18 and 20 during coining, and itself undergoes the bulk of the deformation. Hence, the coin is equivalent in hardness and wear properties to hardrolled stainless steel. in addition, a U.S. cost is realized as compared with most coinage alloys.
The layers 18 and 20 of stainless steel are preferably clad to the aluminum layer 16 in sheet form under heat and pressure, typically by rolling. Suitable parameters for cladding the stainless steel to the aluminum include a pressure of approximately 20,000 p.s.i. at a temperature of approximately 850 F. The layers 18 and 20 may be clad to the aluminum layer 16 in the manner taught by U.S. Pat. No. 2,782,498, issued Feb. 26, I957. Thereafter, the sheets may be transformed into coins by a conventional coining press. By way of illustration and not by way of limitation, the coin 10 may have a combined thickness of 0.06 inch with layer 16 having a thickness of approximately 0.054 inch with each of the layers 18 and 20 having a thickness of approximately 0.003 inch. As will be apparent from FIG. 2, the contour of the configurations 12 and 14 have a height greater than the thickness of either of the layers 18 and 20 whereby the middle layer 16 is deformed so as to correspond to the configurations l2 and 14.
The present invention may be embodied in other specific fonns without departing from the spirit or essential attributes thereof.
1. A coin comprising a middle layer of aluminum sandwiched between clad layers of stainless steel, the thickness of said middle layer being between and 95 percent of the combined thickness of said three layers, at least one major face of the coin having a configuration thereon partially formed in the middle layer, and said layers having substantially the same light reflective properties.
2. A coin in accordance with claim 1 wherein said middle layer has a thickness of percent of the combined thickness of said three layers, each of the layers of stainless steel being of substantially the same thickness 3. A coin in accordance with claim 1 including a milled periphery on said layers.