US3543554A - Apparatus for punching and forming articles from sheet stock - Google Patents

Description

Dec. 1, 1970 HQAGLAND ETAL APPARATUS FOR PUNCHING AND FORMING ARTICLES FROM SHEET STOCK 3 Sheets-Sheet 1 Filed NOV. 25, 196.8

INVENTORS.

d 2 Hr e ww m 3 may Bfi A n om 00 wwfi W AT TORNEY Dec. 1, 1970 B, HOAGLAND ET AL 3,543,554

APPARATUS FOR PUNCHING AND FORMING ARTICLES FROM SHEET STOCK Filed NOV. 25, 1968 Sheets-Sheet 2 INVENTORS. fli/iozz 3 Hang/ma, Gear 5 6roenez; BY 67a grizJfiQ'/e, Z ZI/X Zam A. Watcher ATTORNEY Dec. 1, 1970 M. B. HOAGLAND ET AL APPARATUS FOR PUNCHING AND FORMING ARTICLES FROM SHEET STOCK Filed Nov. 25 1968 3 Sheets-Sheet 3 INVENTORS. 7%?!022 b? Hoag/zma, Gear e (l Groezzer, BY (/0 $0 15% a 1/4? 22222: fl. Weak/ ar ATTORNEY United States Patent US. Cl. 72-185 7 Claims ABSTRACT OF THE DISCLOSURE A metal forming machine has first and second rolls carrying punches and dies respectively to punch blanks from a sheet metal strip fitted between the rolls. Coining punches carried by the second roll within the dies cooperate with other coining punches carried by a third roll to coin the blanks. The punches on the third roll are provided with a rocking action to allow the cooperating punch faces to remain parallel throughout the coining operation.

This invention relates to an apparatus for forming articles from sheet stock in two stages and more particularly, to an apparatus for blanking and coining articles from sheet metal stock wherein the metal forming tools are carried by rotating rolls.

Heretofore, it has been the practice to manufacture coins, tokens, medals and the like by punching blanks from sheet stock with a reciprocating stamping machine and then individually transferring the blanks to a reciprocating coining machine for embossing the blanks. That arrangement necessarily results in a low production rate for each set of machines and where the production requirements are high, it dictates duplication of equipment which consumes large amounts of factory floor space.

It is therefore an object of the invention to provide apparatus for punching and forming articles from sheet stock at a higher rate than was practical heretofore.

It is a further object to provide apparatus for producing coined articles from sheet stock with a rolling action as opposed to a reciprocating action.

The invention is carried out by providing a plurality of cooperating rolls carrying blanking tools and metal forming tools for producing blanks from sheet stock and forming the blanks into finished articles.

The invention is further carried out by providing a first roll carrying punches cooperating with dies carried by a second roll for punching blanks from sheet stock passing between the rolls during rotation thereof. Forming tools within the dies on a second roll cooperate with other forming tools carried by a third roll for forming the blanks in the finished articles. It is particularly contemplated that the forming tools comprise coining punches.

The above and other advantages will be made more apparent from the following specification taken in conjunction with the accompanying drawings wherein like reference numerals refer to like parts and wherein:

FIG. 1 is a perspective view of a rollstand containing apparatus according to the invention;

FIG. 2 is a partly broken away elevational view of the rollstand of FIG. 1;

FIG. 3 is a cross-sectional view of the working rolls of the rollstand of FIG. 1 according to the invention;

FIG. 4 is a perspective detail view of a blanking punch;

FIG. 5 is a cross-sectional detail view of a rocker punch and a coining punch mounted in their repsective working rolls according to the invention; and

FIGS. 6 and 7 are front and side elevational views of a rocker punch according to the invention.

Referring to FIGS. 1 and 2, a rollstand 10 comprises a base 12, vertical frame members 14 and a top portion 16 secured to the base 12 by a plurality of tie bolts 18. The vertical frame members 14 support an upper back-up roll 20, a first working roll 22 below the upper backup roll 20, a second working roll 24 mounted below the first working roll 22, a third working roll 26 below the second working roll 24 and a lower back-up roll 28 below the third working roll 26 which is supported by the base 12. Each of the rolls 20 28 is carried at each end by a bearing block .30, each containing a roller bearing assembly 32 which rotatably support shafts 34 at the ends of each roll 20-28. The bearing blocks 30 are retained by the vertical frame members 14. The rolls 20-28 are driven by a motor 36 through a belt 38, a gear box 40, a clutch 42 and a power shaft 44. The power shaft 44 is drivingly connected to the third working roll 28 at one end of the working roll 26. The same end of the working roll 26 carries a gear 46 which meshes with a gear 48 on the second working roll 24 which in turn meshes with a gear 50 in the first working roll 22 so that as the third working roll 28 is rotatably driven by the power shaft 44, the second and first working rolls 24 and 22 are driven synchronously therewith. All of the rolls 20-28 have spaced shoulders 52 each in contact with the shoulder of the adjacent roll. A pair of hydraulically operated pressure cylinders 54 each bear against a bearing block 30 of the upper back-up roll 20 and against the top portion 16 to exert downward force on the upper back-up roll 28. The force is exerted through the shoulders 52 of the working rolls 22-26 to the lower back-up roll 28. The roll stand 10 accepts metal sheet stock 56 which passes between the first and second working rolls 22 and 24 at the center thereof intermediate the shoulders 52.

FIG. 3 shows a cross-sectional view of the three working rolls 2226. The first working roll 22 comprises a roll 58 with an apertured cover plate 60 secured thereto. Each aperture 62 of the cover plate 60 is cylindrical and terminates in a flared, inner portion 64. Each aperture 62 carries a blanking punch 66. As best shown in FIG. 4, the blanking punch 66 comprises a cylindrical body 68 terminating in a flared inner portion 70 which seats within the flared inner portion 64 of the cover plate '60. The outer end of the punch 66 terminates in a truncated conical head 72 connected to the cylindrical body 68 at its smallest diameter and flaring outwardly. The punch face 74 is ground to a cylindrically concave configuration. The punch 66 is located on the first working roll 22 such that the cylinder axis of the punch face 74 runs transversely to the axis of rotation of the roll 22. While only two punches 66 are shown in FIG. 3, it is usually desirable in practice to use a large number of punches 66 as indicated in FIG. 2. Of course, the metal forming tools, to be described, of the second and third working rolls 24 and 26 must correspond in number and location to the punches 66 on the first working roll 22. To facilitate assembly and disassembly of the first working roll 22, the cover plate 60 is divided into segments 60a and 60b as shown on FIG. 2, which are secured to the roll 58 by bolts 76.

The second working roll 24 includes a hollow roll 78 defining a central opening 80. The roll 78 is surrounded by an apertured spacer 82 and an apertured cover plate 84. As best shown in FIG. 5, a blanking die for coacting with the blanking punch comprises a hollow cylindrical die bushing 86 having at its inner end a flange 88 extending radially outwardly is located within each aperture of the cover plate 84. The flange 88 of the die bushing 86 rests against a support block 90 which has a curved inner surface 92 in engagement with the roll 78. The size of the die bushing 86 is so selected that the blanking punch 66 may enter the die bushing 86 to stamp or cut discs 94 of metal from the sheet stock 56 as the first and second working rolls 22 and 24 rotate. A cylindrical coining punch 96 is located within each die bushing 86 and normally rests against the support block 90. Each coining punch 96 has a configuration embossed on the face thereof as by engraving, for example, in accordance with the form desired to be imparted to one side of the disc 94. A stationary eccentric cam 98 is mounted within the central opening 80 of the roll 78. Radial passages 102 in the roll 78 extend from the central opening 80 toward the center of each coining punch 96. Ejector rods 104 extend through the radial passages 102 and make contact at either end with the cam 98 and an ejector pin 105 which is slidably mounted within a hole 107 in the support block 90. The ejector pin contacts the coining punch 96. The cam 98 is circular in cross-section and concentric with the roll 78 throughout the right-hand portion thereof as viewed in FIG. 3, and contains a rise portion 106 at its left-hand side so that as the second roll 26 rotates clockwise, the upper ejector rod 104 will not move longitudinally until the working roll 24 has rotated more than 180 and then due to the rise portion of the cam 98, the ejector rod 102 will move outwardly to urge the corresponding ejector pin 105 and coining punch 96 outwardly to eject the disc 94 from the die bushing 86. Therefore, the disc 94 is retained within the die bushing 86 at the time the die bushing 86 is moved to its lowermost position. Where a large number of die bushings 86 and coining punches 96 are incorporated on the second working roll 24, the corresponding support block 90 will essentially fill the space between the roll 78 and the cover plate 84 so that the spacer 82 is unnecessary. For convenience, as shown in FIG. 2, the cover plate 84 is comprised of separate segments 84a and 84b secured to the roll 78 by bolts 76.

The third working roll 26 comprises a roll 108 surrounded by an apertured cover plate 110. The cover plate, has integral flanges 112 at either end to space the apertured cover plate 110 from the roll 108. The cover plate 110 is separated into segments 110a and 11% secured to the roll 108 by bolts 76 as shown in FIG. 2 to facilitate assembly. The periphery of the roll 108 contains a number of curved pockets 114 each for receiving a rocker punch 116 which is a coining punch adapted to coact with the coining punch 96. The face of the rocker punch 116 is formed with a configuration which is to be embossed on the disc 94 when the second and third working rolls 24 and 26 rotate to bring the disc 94 into compressliiat between the coining punch 96 and the rocker punch As best shown in FIGS. 5, 6 and 7, the rocker punch 116 has a compound curved seat 118 which mates with the pocket 114. As illustrated in FIG. 6, the curvature of the seat 118 as would be revealed by a section through the rocker punch 116 perpendicular to the axis of the. first working roll 22, is cylindrical with a radius X and has its center on the punch face 120 offset from the can terline 122 of the portion 116 by a small distance Y. As seen in FIG. 7, the curvature of the seat 118 as revealed by a section parallel to the axis of the first working roll 22 is cylindrical of radius R smaller than the radius X and has its center of curvature on the centerline 122. This latter curvature minimizes stress on the rocker punch 116. A fiat 123 on each side of the rocker punch 116 engaging a flat wall portion (not shown) on the pocket 114 prevents lateral rocking of the rocker punch 116 about the radius R. A seal 124 comprises a metal ring 126 pressed into an apertured wall 128 and a flexible annular web 130 bonded to the ring 126. The annular web 130 defines an opening which receives the rocker punch 116, A spring 132 is provided to bias the rocker punch 116 in such a direction that the face 120 of the rocker portion 116 will be roughly parallel to the face of the coining punch 96 when the rocker punch 116 first enters the die bushing 86 upon rotation of the second and third working rolls 24 and 26. The spring 132 has at one end a stem portion 134 inserted into a bore 136 in the cover plate 110. The spring 132 is formed into a single coil 138 adjacent the stem portion 134 and a convolution of several coils 140 spaced from the single coil 138. The spring 132 includes an arcuate portion 142 bearing against the side of the rocker punch 116 near the seat 118, and terminates in a double coil and stem portion, not shown, similar to that portion just described. This spring configuration allows the arcuate portion 142 of the spring 132 to swing in an arc following the movement of the rocker punch 116 and yet remains spaced from the pocket 114 'by a distance suflicient to prevent the arcuate portion 142 from slipping between the pocket 114 and the seat 118 in the event that the rocker punch 116 momentarily bounces and loses contact with the pocket 114. A rivet 144 in the cover plate has its head protruding underneath the cover plate 110 to form a stop for limiting the movement of the rocker punch 116 in the direction of spring bias. The roll 108 contains a central bore 146 and passage 148 connecting the bore 146 to the pockets 114 for supplying lubricant to the pockets 114.

It is important that the face of the rocker punch 116 remain parallel to the face of the coining punch 96 during the time both punches are coining the disc 94 to maintain a uniform mean thickness of the coin produced from the disc 94. For this reason, the rocker punch 116 is provided with the curved seat 118 to allow rocking of the punch 116 throughout the several degrees of movement of the second and third working rolls 24 and 26 in which the coining operation takes place. By placing the center of curvature of the radius X on the face of the punch 116 the forces applied to the punch 116 keep the face 120 aligned parallel with the face of the coining punch 96. These forces are so large that the biasing force of the spring 132 is negligible by comparison. The large forces acting between the seat 118 and the pocket 114 produce a frictional resistance which tends to retard the proper working movement of the rocker punch 116. For this reason the center of the radius X is sightly offset from the centerline 122 of the rocker punch 116 in the direction of rotation of the first working roll 22 thereby producing a biasing force on the rocker punch 116 just sufiicient to overcome the frictional forces. It is not necessary that the rocker punch 116 when spring biased against the rivet 144 be exactly aligned parallel with the coining punch 96 at first contact with the disc 94. It is allowable for the trailing edge of the rocker punch 116 to initially contact the disc 94 because the force applied to that side of the punch will promptly cause rotation of the punch 116 into parallel alignment without gouging the disc 94 at the point of contact.

In operation of this apparatus, the power shaft 44 rotates the third working roll 26 which in turn drives the other working rolls 22 and 24 through the gears 46, 48 and 50. The back-up rolls 20 and 28 idle at the same peripheral speed as the working rolls 22-26. The pressure cylinders '54 apply a downward force on the upper backup roll 20 which transmits the force to the working rolls 22-26 through the shoulders 52, thereby providing adequate working force to the metal forming tools, i.e., the blanking punches 66, the die bushing 86, the coining punches 96 and the rocker portions 114. The metal sheet stock 56 is fed between the first and second working rolls 22 and 24 whereupon the coaction of the blanking punch 66 and the die bushings 86 blank the metal discs 94 from the sheet stock 56. The disc 94, having been pressed into the die bushing 86 by the blanking punch 66, is retained within the die bushing 86. When, due to the rotation of the se ond working roll 24, the disc 94 is carried down towards the third working roll 26, the rocker punch 114 enters the die bushing 86 and assumes a position with its face 120 parallel to the face of the coining punch 96. The disc 94 is then coined by compression between the coining punch 94 and the rocker punch 116 to emboss the pattern of the punches 96 and 116 onto either side of the disc 94. The resulting article is a finished coin, token or metal which is ejected from the die bushing 86 when the second working roll 24 rotates past the coining station and the corresponding ejector rod 104 engages the rise 106 of the cam 98 and moves the coining punch 96 outwardly. As soon as the rocker punch 116 is withdrawn from the die bushing 86 after the coining operation it is biased back to the rivet 144 in readiness for the next coining operation.

In practice, an apparatus of the type described has been built and operated. This apparatus includes working rolls 22-26 having a nominal diameter of 8.5 inches and the first working roll 22 contained 102 blanking punches 66 and the other working rolls 24 and 26 contained a like number of cooperating metal forming tools. The tools were sized to produce coin-like tokens of approximately 0.75 inch in diameter. The metal sheet stock 56 was 0.048 inch thick and comprised guilding metal which is 95% copper and tin and zinc. The working rolls 22-26 were operated at 52 rpm. thereby producing in excess of 5000 tokens per minute. In addition, the perforated skeleton of the sheet stock 56 was fed to a second roll stand of similar structure which produced additional tokens from the same sheet stock 56 by using the material remaining between the holes in the skeleton so that the combined rate of production exceeded 10,000 tokens per minute from a single strip of metal sheet stock 56. The total floor space occupied by the two roll stands and supporting equipment was considerably less than that required by a suflicient number of conventional reciprocating stamping and coining machines required to achieve the same production rate, and in addition, fewer operators were required.

The embodiment of the invention described herein is for purposes of illustration and the scope of the invention is intended to be limited only by the following claims.

We claim:

1. An apparatus for forming articles from sheet stock comprising a first roll carrying a plurality of blanking punches,

a second roll in cooperative arrangement with the first roll for accepting sheet stock therebetween carrying a plurality of blanking dies adapted to register with the blanking punches upon rotation of the rolls for forming blanks from sheet stock and for retaining the blanks, and a forming tool positioned within each die,

a third roll in cooperative arrangement with the second roll and opposite the first roll, the third roll carrying a plurality of forming tools each disposed to register with and to cooperate with a forming tool on the second roll to form articles from the blanks retained within the dies,

and means synchronously driving the rolls.

2. An apparatus for forming articles from sheet material stock comprising a first roll carrying a plurality of blanking punches,

a second roll in cooperative arrangement with the first roll for accepting sheet metal stock therebetween carrying a plurality of blanking dies adapted to register with the blanking punches upon rotation of the rolls for forming blanks from the sheet stock and for retaining the blanks, and a metal forming punch positioned within each die,

a third roll in cooperative arrangement with the second roll and opposite the first roll, the third roll carrying a plurality of metal forming punches each disposed to register with and to cooperate with a metal forming punch on the second roll to form articles from the blanks retained within the dies,

means for ejecting the formed articles from the dies,

and means for synchronously driving the rolls,

whereby blanks are formed from sheet metal stock by the coaction of the first and second rolls and the blanks are formed into articles by the coaction of the second and third rolls.

3. An apparatus for forming coined articles from sheet metal stock comprising a first roll carrying a plurality of blanking punches,

a second roll in cooperative arrangement with the first roll for accepting sheet metal stock therebetween carrying a plurality of blanking dies adapted to register with the blanking punches upon rotation of the rolls for forming blanks from the sheet metal stock and for retaining the blanks, and a coining punch positioned within each die,

a third roll in cooperative arrangement with the second roll and opposite the first roll, the third roll carrying a plurality of coining punches each disposed to register with and to cooperate with a coining punch on the second roll to form coined articles from the blanks retained within the dies,

motor means to drive one of the rolls,

and means for synchronously driving the others of the rolls relative to the motor driven rolls,

whereby blanks are formed from sheet metal stock by the coaction of the first and second rolls and the blanks are coined into articles by the coaction of the second and third rolls.

4. An apparatus for forming coined articles from sheet metal stock comprising a first roll carrying a plurality of blanking punches,

a second roll in cooperative arrangement with the first roll for accepting sheet metal stock therebetween carrying a plurality of blanking dies adapted to register with the blanking punches upon rotation of the rolls for forming blanks from the sheet metal stock and for retaining the blanks, and a coining punch positioned within each die,

a third roll in cooperative arrangement with the second roll and opposite the first roll, the third roll carrying a plurality of coining punches each disposed to register with and to cooperate with a coining punch on the second roll to form coined articles from the blanks retained within the dies, and means for mounting each coining punch on the third roll for maintaining the punch faces parallel to faces of the corresponding punches on the second roll while the punches are in engagement with the blanks,

motor means to drive one of the rolls,

and means for synchronously driving the others of the rolls relative to the motor driven roll,

whereby blanks are formed from sheet metal stock by the coaction of the first and second rolls and the blanks are coined into articles by the coaction of the second and third rolls.

5. An apparatus for forming coined articles from sheet metal stock comprising a first roll carrying a plurality of blanking punches,

a second roll in cooperative arrangement with the first roll for accepting sheet metal stock therebetween carrying a plurality of blanking dies adapted to register with the blanking punches upon rotation of the rolls for forming blanks from the sheet metal stock and for retaining the blanks, and a coining punch positioned within each die,

a third roll in cooperative arrangement with the second roll and opposite the first roll, the third roll carrying a plurality of coining punches each disposed to register with and to cooperate with a coining punch on the second roll to form coined articles from the blanks retained within the dies,

means for mounting each coining punch on the third roll for maintaining the punch faces parallel to faces of the corresponding punches on the second rollwhile the punches are in engagement with the blanks, the mounting means comprising a curved back portion opposite the face of each punch of the third roll, the center of curvature of the back portion lying substantially at the punch face, and a mating pocket with a similar curvature in the third roll for receiving each punch and formed to allow a rocking motion of the punch within the pocket about an axis blanks are coined into articles by the coaction of the second and third rolls.

7. An apparatus for forming coined articles from sheet metal stock comprising a first roll carrying a plurality of blanking punches,

at second roll in cooperative arrangement with the first roll for accepting sheet metal stock therebetween carrying a plurality of blanking dies adapted to register with the blanking punches upon rotation of the rolls for forming blanks from the sheet metal stock and for retaining the blanks, and a coining punch positioned within each die,

parallel to the axes of the rolls, a third roll in cooperative arrangement with the second whereby blanks are formed from sheet metal stock by roll and opposite the first roll, the third roll carrythe coaction of the first and second rolls and the ing a plurality of coining punches each disposed to blanks are coined into articles by the coaction of the register with and to cooperate with a coining punch second and third rolls. on the second roll to form coined articles from the 6. An apparatus for forming coined articles from sheet blanks retained within the dies, metal stock comprising means for mounting each coining punch on the third a first roll carrying a plurality of blanking punches, roll for maintaining the punch faces parallel to faces a second roll in cooperative arrangement with the first of the corresponding punches on the second roll while roll for accepting sheet metal stock therebetween the punches are in engagement with the blanks, carrying a plurality of blanking dies adapted to regcomprising a curved back portion opposite the face of ister with the blanking punches upon rotation of the each punch of the third roll, the center of curvature rolls for forming blanks from the sheet metal stock of the back portion lying substantially at the punch and for retaining the blanks, and a coining punch face, and a mating pocket with a similar curvature positioned within each die, in the third roll for receiving each punch and formed third roll in cooperative arrangement with the secto allow a rocking motion of the punch within the ond roll and opposite the first roll, the third roll pocket about an axis parallel to the axes of the rolls carrying a plurality of coining punches each disposed the center of curvature of the back portion of the to register with and to cooperate with a coining pocket being offset from the center of the punch in punch on the second roll to form coined articles from the direction of rotation of the third roll by an the blanks retained within the dies, amount sufiicient to overcome the frictional resistance means for mounting each coining punch on the third to the rocking motion of the punch,

roll for maintaining the punch faces parallel to faces and each punch in the third roll having resilient means of the corresponding punches on the second roll while engaging the roll and the punch for biasing the punch the punches are in engagement with the blanks, the to a predetermined angular orientation prior to enmounting means comprising a curved back portion gagement of the punch with the blank, opposite the face of each punch of the third roll, the motor means to drive one of the rolls, center of curvature of the back portion lying suband means for synchronously driving the others of the stantially at the punch face, and a mating pocket ll relative to the motor driven roll, with a similar curvature in the third roll for receiving 40 h b blank r formed from sheet metal stock by each plmCh an med to l ow a rocking tion of the coaction of the first and second rolls and the the punch Within the Pocket about an axis parallel blanks are coined into articles by the line coaction to the axes of the rolls, the center of curvature of f th nd nd third rolls. the back portion and of the pocket being offset from the center of the punch in the direction of rotation References Cited of the third roll by an amount suflicient to overcome UNITED STATES PATENTS g1; gictlonal resistance to the rocking motion of the 2,872,887 2/1959 Pratuflon "h and means for synchronously driving the rolls, whereby blanks are formed from sheet metal stock by LOWELL LARSON Primary Exammer the coaction of the first and second rolls and the Us. CL

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent M 3,543,554 Dated December 1, 1970 Inventor(s) Milton B. Hoagland, George E. Greener, Clayton J.

Trible, and William A. Fletcher It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 8, Claim 7, line 42, delete the word "line".

Signed and sealed this 1 3th day of April 1971 (SEAL) Attest:

EDWARD M.FLETGHER,JR. WILLIAM E. SCHUYLER, J'I Commissioner of Patent:

Attesting Officer

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