Method and apparatus for producing coins

Aug. 29, 1967 _{c F} stegman, sr 3,338,084

METHOD AND APPARATUS FOR PRODUCING COINS

Filed Feb; 23, 1965 , . ' ' 3 Sheets-Sheet 1

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Aug. 29, 1967

C. F. STEGMAN, SR

3,338,084

METHOD AND APPARATUS FOR PRODUCING COINS

Filed Feb. 23, 1965

Sheets-Sheet z

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Aug. 29, 1967 c. _R stegman, sr 3,338,084

METHOD AND APPARATUS FOR PRODUCING COINS

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United States Patent Office 3,338,084 _____ Patented Aug. 29, 1967

338 084 METHOD AND APPARATUS FOR PRODUCING COINS

Clifford F. Stegman, Sr., 5811 Twin Oaks Drive, Cincinnati, Ohio 45224

Filed Feb. 23,1965, Ser. No. 434,329 3 Claims. (CI. 72—333)

This invention relates to a method and apparatus for manufacturing coins and tokens and more particularly, the invention is directed toward improving the efficiency of the manufacture of coins and tokens.

Reference will be made herein to the manufacture of coins but it is to be understood that the invention is equally applicable to tokens, medallions and like small, flat, metafile objects having indicia embossed in the surface thereof or metal removed from portions thereof.

Coins have been manufactured for many years without any fundamental changes in either the method or the apparatus for making them. In general, the process begins witii long strips of material received from a rolling mill in coils. The width of the strips varies depending upon the size and number of coin blanks to be punched out of the strip with each stroke of the press. The strip is fed incrementally into a blanking press by which coin blanks 25 are punched out. These blanks are cleaned and deburred usually by revolving them in tumbling barrels together wnth deburring and brightening materials. The blanks may then be edge-rolled or otherwise preformed, the edgerolling being performed in apparatus which rolls the edges 30 of the coins to a precise diameter.

The thus formed blanks are then subjected to a coining operation. In that operation each blank is confined in a constricting collar between two embossing dies. The dies are brought together to emboss the coin on each side, 35 the constricting collar restraining the outward flow of material and thereby determining the outside diameter of the coin. The coining apparatus and the manner in which the coins are fed to the apparatus is widely varied but in the various machines, the coining through the use of two 40 dies operating in a constricting collar remains the same.

Among the disadvantages of the present practices is the requirement for distinct blanking apparatus, deburring apparatus and coining apparatus with handling of the coins required between operations all of which results ⁴⁵in a low volume output based on the capital investment of machinery and the labor involved in the operations. In tiie production of coin money, these factors have resulted in coin shortages.

_ An objective of the apparatus has been to provide a single machine which receives strip stock at its input and delivers finished coins at its output. To this end, the invention contemplates the reversal of the operations presently constituting the present practice of making coins to the extent that the coin is embossed or otherwise treated to form it while in the strip form and, after the coin is formed, blanking the coin out of the strip. Through this reversal of the sequence of the operations performed on the material certain intermediate steps of the prior practices are eliminated. For example, it is not necessary to size the coin properly so that it can be received in the constricting collar of the coining apparatus for the strip stock surrounding the coin constitutes its own constricting collar and exerts a sufficient lateral constricting force to cause the metal in the stock to flow into the configurated ⁶⁵recesses of the dies under the embossing pressure.

It has been another objective of the invention to provide substantially uniform constricting pressure and hence unidirectional flow of metal during the embossing operation by forming transverse slots in the stock between areas which are to be embossed. The slots permit flow of metal longitudinally of the strip to substantially the same extent as is permitted transversely of the strip, the dimensions of the excess material transversely and longitudinally around each coin being approximately the same. This transverse slotting to create unfonnity in the constricting force of the surrounding metal appears to be critical to the success of the apparatus; for in treating thick metals, a lack of uniformity in the flow of metal tends to distort the surface configuration of the embossed coin.

If it is desired to produce a superior quality coin, the coins delivered from the coining and blanking apparatus described above may be automatically fed into an attached grinding device for diameter sizing as well as apparatus for serrating the edges of the coins. Thus, it is possible to produce even the finest quality coins with a continuous flow of material and with minimal handling of the stock as it moves through its successive stages of operations.

The several features of the invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the embossing and blanking apparatus of the invention,

FIG. 2 is a disassembled perspective view of one embodiment of the dies and strip feeding mechanism,

FIGS. 3 and 4 are cross-sectional views of the die structure showing the operations performed on the stripping stock,

FIGS. 5 and 6 are plan views of strip stock illustrating sequences of operations which may be performed on the stock through the invention, and

FIG. 7 is a diagrammatic plan view of strip stock formed through an alternative embodiment.

FIG. 1 shows a press 10 in which upper and lower dies 11 and 12 respectively of the present invention are mounted. The apparatus has a base 13 on which a fixed platen 14 is mounted and a vertically reciprocating ram 15 on which a movable platen 16 is mounted. The dies 11 and 12 are fixed to the respective platens and are guided into proper registry with each other by guide pins 17 which are located at the four corners of the platens.

Incased in a housing 20 is operating mechanism for reciprocating the ram 15. The stroke of the ram is such that in its uppermost position it raises the upper die a distance to permit strip stock 21 to be fed between the dies and in its lowermost position it brings the upper die to a position in which it is precisely spaced from the lower die by that distance required for the proper embossing of the coins. The raw strip stock 21 is fed intermittently by a feeding mechanism 22 between the upper and lower dies 11 and 12 respectively in timed relation to the reciprocation of the upper die so that as the upper die is 53 raised, the stock is fed a distance equal to the centers of adjacent coins being formed.

Except for the die structure, the press and feeding apparatus is known and apparatus selected from a number of different types can be used.

Representative die structure and strip feeding mechanism is illustrated in FIG. 2. The lower fixed platen 14 has the guide pins 17 fixed to it, the guide pins projecting vertically above the upper surface of the platen. The upper platen 16 is fitted at its corners with the bearings 25 having holes 26 therethrough through which the guide pins 17 pass. The bearings 25 are preferably of the ballin-race variety which assures precise alignment of the dies as the upper platen is reciproated in respect to the lower platen. The upper platen carries a cam lug 27 having an inclined cam surface 28 and a vertical dwell surface 29 which are engageable with a slide 30 reciprocably mounted in a fixed housing 31. The housing 31 car50

3.338.084 are tapered and are adapted to engage the pilot holes 42 formed in the strip stock by the punch 40. The cooperation of the pilot pins 50 with the pilot holes 42 positively precisely locates the stock in the proper position with 5 respect to the dies 11 and 12.

The lower die 12 has a guide plate 64 mounted on its upper surface, the guide plate 64 having a downwardly facing channel 65 which receives the stock and guides it in its traverse through the dies. The width of IQ the channel 65 is sufficiently greater than the width of the strip stock to permit the strip stock to flow transversely without binding against the soles of the guide channel. The channel should be narrow enough, however, to limit the sidewise movement of the strip so that the 15 pilot holes 42 will always be in position to be engaged by the pilot pins 50. A rectangular opening 66 is formed in the surface of the guide plate 64 to expose the lower die sections to the upper die sections for the performance of the required operations.

A stripper plate 67 is secured to the upper die shoes 55 by pins 68 which are slidable in the die shoe. The pins are headed at their upper ends to limit their downward movement and are fixed at their lower ends to the stripper plate. Compression springs 69 surrounds each 25 pin to urge the stripper plate 67 in a downward direction.

The stripper plate 67 has holes 70, 71, 72 and 73 through which the piercing punch 40, the dies 53 and 56 and the punch 59 may pass. The stripper plate has longitudinal grooves 74 presenting an elongated central foot 75 which 30 engages the stock while the sides of the guide plate 64 are received in the grooves 74.

The operation of the invention is illustrated by reference to FIGS. 3 and 4. In FIG. 3 the upper platen 16 is in its raised position and the strip stock 21 has been ad35 vanced one stage by the gripping wheels 32 of the feeding mechanism 22. When the platen 16 is driven to its lowermost position illustrated in FIG. 4, the first operation performed on the stock is the punching out of the slot 41 and the pilot holes 42 by the piercing punch 40. ⁴⁰ The platen 16 is raised, the strip 21 is fed another increment, and the platen 16 is lowered. As the platen is lowered, the first pair of pilot pins 50 engage the pilot holes 42 previously punched on the stock thereby precisely locating it with respect to the forming dies 11 and ₄₅ 12, the pins 50 thereafter passing into the pilot holes 51 of the lower die shoe 12 and a second slot 41 and pilot holes 42 are punched. In the third stage of operation at station 47, the upper preforming die 53 compresses the stock against the lower performing die 54 to effect an ini50 tial shaping or flow of the metal toward the general configuration ultimately desired in the finishing coin, the formation of a shoulder 57 being illustrated by way of example.

As the platen is driven downwardly in each operation, 55 the stock is first engaged by the pilot pins 50 to provide its precise positioning and is thereafter engaged by the stripper plate 67 under the rather considerable pressure of the compression springs 69. Thereafter the punches and dies perform their operations. In the upper stroke of the 6Q platen 16, the stripper plate 67 remains in engagement with the stock under the pressure of the springs 60 until the punches and dies have been raised out of engagement with the stock. Thereafter the stripper plate is raised with the die structure out of the way of the strip 55 so that it can be fed. The dwell surface 29 on the cam lug 27 prevents movement of the slide 30 in a direction to advance the strip until the stripper plate and locating pilot pins have moved out of the way of the strip.

The upper platen 16 is raised, the strip 21 advanced, ₇₀ and the platen is driven downwardly to perform the final embossing stage. In that stage, the upper embossing die 56 compresses the strip against the lower embossing die 55 to complete the final formation of the surface configuration of the coins. In this operation it is critically 75 important that under the pressure of the dies the metal ries a pair of upper and lower gripping wheels 32, only the upper wheel being shown. Each wheel is attached by means of an overrunning one-way clutch to a pinion gear 33 which meshes with a rack 34 on the slide 30. The one-way clutch permits the pinion 33 to drive the gear 34 positively when the slide 30 moves toward the left as viewed in FIG. 2 but when the slide moves to the right, the pinion gear rotates freely with respect to the gripping wheel 32.

A compression spring 35 engages the slide and urges it toward the left as viewed in FIG. 2. In the operation of the feeder 22, on the downward stroke of the upper platen 16 the cam lug 27 drives the slide toward the right compressing the spring 35. Because the pinion can turn freely with respect to the gripping wheels 32, there is no rotary movement of the friction wheels during this portion of the operation. On the upward stroke, the movement of the cam lug 27 out of the way of the slide 30 permits the compression spring 35 to expand driving the slide 30 toward the left. The rack 34 carried by the slide rotates the pinion 33 which, through the clutch causes the wheels 32 to rotate thereby driving the strip stock longitudinally with respect to the dies.

The lower die 12, in the illustrated embodiment, has a female piercing die 37 having an elongated transverse slot 38 terminated in two holes 39. The upper die 11 has a mating piercing punch 40 which when driven through the strip stock 21 into the female die 37 forms a stress relieving slot 41 as well as two pilot holes 42 in the strip stock.

As shown in FIGS. 3 and 4, a chute 43 is provided below the slot 38 and holes 39 through which the scrap pieces punched out of the strip are conveyed away. Adjacent the piercing dies is an unused space indicated at 46 whose length is equal to the distance of each advance of the strip stock. Adjacent that space are, sequentially, a preforming station 47, an embossing station 48 and a blanking station 49. Each of these stations has, at its four corners, pilot pins 50 in the upper die 11 and mating holes 51 in the lower die 12. The unused space 46 permits the stock to be advanced to a position in which the pilot holes 42 are engageable by the pilot pins 50 at four corners surrounding the area to be formed at the preforming station, thereby assuring accuracy in the alignment of the dies with the stock at that station as well as at succeeding stations. The preforming station 47 is constituted by preforming embossing dies 53 and 54 on the lower and upper dies 11 and 12 respectively. The preforming dies are not always necessary but when the complete embossing of the coin requires substantial metal flow to create the relief in the surface of the metal, one or more preforming dies may be employed to move masses of metal into a position for the final embossing operation. In the illustrated embodiment the preforming dies 53 and 54 are adapted to form a peripheral shoulder or border in the area indicated at 57 on the dies.

The embossing station 48 adjacent the preforming dies 53 and 54 is constituted by a lower embossing die 55 and an upper embossing die 56. These dies compress the metal in the blank to perform the final embossing operation.

The blanking station 49 adjacent the embossing dies 55, 56 comprises a lower female blanking die 58 and an upper blanking punch 59 which separates the embossed coin from the strip stock. A chute 60 (FIGS. 3 and 4) is provided below the female die 58 to receive blanked out coins and to convey them away for further handling.

In the upper dies, the punches 40 and 59 and the embossing dies 53 and 56 are mounted on an upper die shoe 63 which in turn is fixed to the upper platen 16. The pilot pins 50 are mounted on the upper die shoe 63 between the successive stages of punches and preforming or embossing dies so that each operating station has four pilot pins around it. The lower die 12 has corresponding holes 51 to receive the pilot pins 50. The pilot pins

3,338,084 be permitted to flow uniformly in transverse and longitudinal directions. The width of the strip between the deformed portion and longitudinal edge, indicated at 80, of the strip permits flow transversely and the relief by the slot 41 permits flow longitudinally as at 81. It should 5 be noted that the width of the strip is approximately equal to the longitudinal space between the slots 41. If the apparatus were designed to provide forming operations side by side on a wide strip to form two or more coins simultaneously, it would be necessary to provide iq longitudinal slots 82 between laterally adjacent coins to permit flow of the metal in the transverse direction. A strip formed in this manner is illustrated in FIG. 7.

In addition to permitting uniformity of flow of the metal being deformed, the stock surrounding the coin pro- 15 vides a critically important constricting collar which restricts planar or lateral flow, thereby causing the metal to be driven up into the recesses of the dies under embossing pressure.

The platen 16 is raised, the strip is advanced and the 20 platen is lowered to effect the final operation in the formation of the coin. In that operation, the punch 59 engages the embossed coin and drives it through the femalp, die 58 to separate it from the strip 21. The coins drop out of the lower die and into the tubular chute 60 in which 25 they are conveyed away for further processing or for packaging.

In the foregoing, the operations have been described as a series of stages of operations. It should be understood that after the strip has been fed through the die all stages 30 are performed simultaneously on the strip as indicated in FIG. 4. The condition of the strip after each stage of operation is illustrated in FIG. 5.

As has been indicated above, the preforming operation may not be required. On the other hand, more forming 35 operations than those described may be employed. For example, as illustrated in FIG. 6, the strip may be formed sequentially as follows.

First, the transverse slot 41 and pilot holes 42 are formed. Second, the stock is preformed to form a border 40 or shoulder 85. Third, the stock is further preformed to move masses of metal to positions indicated at 86. Fourth, a coining operation is performed at 87. Fifth, the final embossing stage is performed at 88. Sixth, the metal is pierced to remove portions at 89 as in the formation of tokens and the like. And last, the coin is separated from the stock as at 90.