US 3669014 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
United States Patent Spaw et al.
[ 1' June 13, 1972  MEANS INCLUDING TWO DIE SETS FOR EMBOSSING AND APPLYING FOIL TO A' SHEET  Inventors: Eugene S. Spaw, Leawood; Paul F. Mc-
Grath, Prairie Village, both of Kans; Stanley W. Otto, Platte City, Mo.
Hallmark Cards, Incorporated, Kansas City, Mo.
22 Filed: Aug. 29, 1969 21 App1.No.: 854,105
52 U.s.c1. ..1101/311,101/27,101/90,
 References Cited UNITED STATES PATENTS Apicella ..101/27 Tharp 156/220 Primary Examiner-William B. Penn Assistant E.\'aminerE. M. Coven Attorney-Schmidt, Johnson, Hovey & Williams ABSTRACT A method and apparatus for dry engraving sheets of material wherein the method includes holding a sheet fixed in a first position while die stamping a layer of decorative foil thereon to present a specific design, shifting the sheet to a second position in alignment with an embossing die while retaining control over the sheet during shifting thereof, and holding the 'sheet fixed in the second position while embossing the sheet to form raised areas thereon underlying the foil design impression in exact registration therewith to simulate an engraved ,design. The apparatus includes a pair of side-by-side, op-
positely reciprocable shuttle bars each having a series of vacuum ports therein which communicate with a vacuum source in timed relationship to the reciprocation of the respective bars. The shuttle bars thereby alternately shift new sheets into position for processing and cooperate to simultaneously hold fixed one sheet for foil design stamping thereof and 1,978,790 10/1934 Gould et al.... ..101/27 th h tf t t i b i th fi 2,973,853 3/1961 Freedson... ....,l97/6.6 3,108,537 10/1963 Way et a1 ..101/316 llClaimS,l7DrawingFigures 38 A B c L |11|1.. 1 Z H l l- ,3? .||H||||l'i 4. 49
-1 t|11 1 H1 l- 11. ll 11 I'M."
I ll I I I i 1. v 152 1 I48 met 1 4, 1 259 ao i l|lll1l i le1i %ih M/f1? 1 1 '2I2 %@/Zf 3 234 50b zJl lfio fwL-i 160 Mud "1 4 1 232 1 2 ,1 I11, I
/22. M [I I 272 270 6 -740 as I 1,720 104 1 3'2 426 "62 96a Hhll. I .illllmt 'llWllW' SHEET 20F 4 PATENTEnJun 1 3 [s12 INVENTORS. Eugene S. Spaw ATTORNEYS- Paul E McGrafh BY STanIeg W. OTTO MEANS INCLUDING TWO DIE SETS FOR EMBOSSING I AND APPLYING FOIL TO A SHEET This invention relates to an improved method and apparatus for imprinting paper sheets with decorative and written indicia of a quality comparable to that obtained by conventional en- .graving procedures but which is carried out in accordance with novel techniques and employing special equipment permitting acompletely dry application operation to simplify the printing and significantly increase the efficiency and speed of the sheet processing. More specifically, the invention is concerned with a method and apparatus for applying design defining foil to one face of a sheet of paper in conjunction with embossing of the foil-covered areas of the paper to provide a close simulation of engraving. In fact, the excellence of appearance and fineness of line inherent in wet engraving is now combined with the flexibility of design possible in hot foil stamping where the artist has complete freedom as to depth of embossing and degree of overlap of design details and lines.
w Techniques of wet engraving sheet material have remained static for many years. Although improvements have been made in the composition of engraving inks to provide different colors and to decrease the drying time necessary after application of the ink to the paper, the equipment used for engraving of paper sheets has, for the most part, been used without real change for many years. Ink deposited in the cavities of an engraving plate is applied to the surface of a paper as an opposing counter forces at least portions of the paper sheet into the cavities to thereby cause the ink to adhere to the raised areas of the paper. Application of theengraving ink to three-dimensional areas of the paper imparted perspective and depth to the printing which improved the appearance of the design over printed sheets of a flat character. Engraving has been used not only for printing but also artistic designs and background effects. Engraving in this connection has had wide usage in the greeting card industry, for example.
In part, the improved aesthetic effect obtained from engraving of printing and other designs has been attributable to the fact that a larger quantity of ink is deposited on the sheet as compared with offset printing; for example, and the application of the ink to embossed areas of the sheet added to the appearance of the printing or design by virtue of the shadows observed in normal viewing of the card and the rounded character of the individual lines or areas of the engraved portion of the sheet. The enhanced appearance of engraved letters or designs over flat printed areas is caused in part by the fact that the'embossed area of the sheet is slightly wider than the ink placed thereon so that the side margins of the engraving appear relatively sharp to the viewers eye. When the sheet material is forced into the cavities of the engraving die plate and the ink is deposited on the sheet, the edges of the die defining the letter or design cavities therein sharply limit the outline of the engraved area producing a very accurate letter outline which conforms precisely to the initial letter design. In addition, the use of metal pigmented inks assists in improving the aesthetic characteristics of the wet engraved design by imparting a burnished appearance thereto which may be gold or silver for example, as selected by the artist.
Engraving processes are inherently time-consuming and expensive. However, resort to wet engraving has continued because the quality of the engraved cards is so much better than printed sheets, a premium price may be demanded and obtained for engraved designs over lithographed sheets. One principal limitation on wet engraving has been the necessity of placing the freshly engraved sheets in drying racks in such manner that the sheets do not come into contact one with the other until after completely dry, thus requiring considerable handwork and obviating the possibility of using automated equipment, either of the sheet-fed or roll-fed type. In normal lithography the inks currently in use are sufficiently rapid drying that the printed sheets may simply be stacked one on top of the other as v they emerge from the printing machine. In wet engraving processes though, the engraved paper sheets must be individually placed in drying racks and allowed to remain stacked one above the other until after the ink has on top of the other.
completely dried. Attempts have been made to provide relatively rapid drying engraving inks but the large quantity of ink necessarily deposited on the paper impeded fast drying thereof and thus, for the most part, making it completely unfeasible to stack the sheets one on top of the other until after they have had an opportunity to dry for an extended period of time. Use of heaters to dry the ink after engraving have not been commercially successful because use of heat of sufficient thermal content to effect rapid drying of the ink also adversely affected the paper or the ink itself placed on the paper.
It is therefore the primary object of the present invention to provide an improved method and apparatus for engraving paper sheets with letters or artistic designs utilizing an entirely dry technique which obviates the individual handling of the freshly engraved sheets of past practices while at the same time producing a product of quality equal to or, in some instances, better than wet engraved sheets.
A still further important object of the invention is to provide improved apparatus and a method for dry engraving paper sheets wherein the method lends itself to placement of very intricate designs on the sheet of characteristicswhich were not feasible in wet engraving processes.
Also an object of the invention is to provide a method and apparatus for dry engraving wherein foil substantially conforming to the letters or design to be imprinted on the sheets is initially placed thereon and the material then embossed of a width slightly greater than that of the foil so that a sharp image is produced closely simulating a wet engraved design.
In this connection, a further object of the invention is to provide an improved dry engraving process and apparatus for carrying out such method wherein extremely accurate registration is obtained between the foil stamped on the sheet and the subsequently embossed area thereof by virtue of the fact that the sheet to be processed is initially moved into a foil stamping station and then moved to an embossing station while complete control is maintained over the sheet to avoid misalignment between the foil stamping die and the embossing die of the dry engraving apparatus. The required close control over the sheet material during processing thereof is obtained by use of a vacuum system for holding the sheet material which thus obviates the necessity of using mechanical clamps or the'like and it is, therefore, another object of the invention to provide improved vacuum shuttle bar apparatus for supporting the individual sheets and to effect successive shifting thereof into a foil stamping station, thence to an embossing station, and finally to an area wherethe sheets are stacked one A still further important object of the invention is to provide novel apparatus and a method for dry engraving sheetsof paper wherein high speed operation is possible by virtue of the fact that as each sheet newly presented to the machine for stamping undergoes application of foil thereto, a previously foil stamped sheet is embossed in the same motion of the machine, while a third stamped and embossed sheet is moved to the delivery area. The speed of the dry engraving operation is materially increased by the use of a reciprocable shuttle bar mechanism which employs-components which grip and move the individual sheets along paths of linear travel which are limited solely to the amount of movement necessary to provide clearance between adjacent sets as they are successively shifted, from a supply station to an embossing station and finally to the delivery area. Thus, a further important objectof the invention is to provide improved apparatus for carrying out the novel method of this invention wherein the utilization of reciprocatory paper shifting mechanism permits close control over shifting of the sheets by virtue of the fact that movement of the paper shifting members to opposite ends of their paths of travel may be sensed to control proper sequential gripping of the sheets and release thereof for movement by another reciprocatory member so that as the speed of operationof the apparatus is varied, the required timing of the gripping and shifting components is automatically correlated therewith.
Another important object of the invention is to provide an improved dry engraving process which simulates wet engraving techniques in large measure because of the fact foil of any desired color and pigmentation may be applied to the paper in the stamping operation and is therefore, substantially without limitation as to the design and color possibilities, not only with respect to metallic as well as non-metallic pigments.
In the drawings:
FIG. 1 is an elevational view of improved apparatus for dry engraving sheet material and shown in conjunction with a platen press having a foil stamping die and an embossing die in opposition to backup structure therefor with the press shown fragmentarily and omitting certain of the drive components thereof for clarity;
FIG. 2 is a fragmentary plan view of the apparatus and press as illustrated in FIG. 1;
FIG. 3 is a fragmentary, end elevational view of the structure shown in FIGS. 1 and 2;
FIGS. 4 and 5 are cross-sectional views taken substantially on the lines 4-4 and 55 of FIG. 1;
FIG. 6 is a cross-sectional view taken along line 66 of FIG. 5;
FIG. 7 is a cross-sectional view taken on line 77 of FIG. 1;
FIG. 8 is a diagrammatic view of two of the vacuum shuttle bars forming a part of the apparatus of FIGS. 1 to 7 inclusive and illustrating the oscillating operating plates for shifting the bars as well as the cables for connecting the operating members to respective shuttle bars.
FIG. 9 is a schematic showing of the vacuum source operably coupled to the shuttle bars and the control mechanism associated therewith;
FIGS. 10; 11, 12 and 13 are diagrammatic representations of the sequence of processing of sheets of material as they are successively moved from a supply stack to the foil stamping station, then to the embossing station, and finally to a delivery area;
FIG. 14 is a fragmentary, schematic cross-sectional view showing the foil stamping die and the backup platen therefor and illustrating the way in which foil is impressed on a sheet of material positioned between the stamping die and the platen;
FIG. 15 is a fragmentary, schematic, cross-sectional illustration of the foil impressed on the paper;
FIG, 16 is a fragmentary, schematic, cross-sectional showing of the embossing die and counter therefor showing the way in which the foil stamped paper is embossed ofa slightly larger width than that of the foil initially placed thereon; and
FIG. 17 is a fragmentary, schematic, cross-sectional view of the dry engraved paper processed in accordance with this invention.
Briefly, the present invention contemplates application of foil of desired configuration defining either letters or an artistic design to one face of a sheet of paper followed by embossing of such foil stamped impression while very precise registration is maintained between the foil impression and the area of embossment of the sheet to closely simulate a wet en graved design.
A web of foil on a backing strip is fed between a flat stamping die and a backup platen therefor to cause foil of desired letter or design defining configuration to be applied to the sheet of paper whereupon the sheet is then transferred while close control is maintained thereover, between an embossing die and a counter so that the foil impressed area of the sheet is embossed to a desired degree of a width somewhat greater than that of the foil impressed design whereupon the completed sheet is then directed to a delivery station for subsequent processing without the need of providing for individual drying of each sheet. The dry engraving process is preferably carried out in a press having dual stamping and embossing stations and wherein the individual sheets are successively moved to the stamping and embossing stations by reciprocable vacuum shuttle bars which are oscillated back and forth and communication of a vacuum source therewith is controlled by mechanism operated by structure for reciprocating the paper gripping and shifting bars.
FIGS. 14 to 17 inclusive schematically illustrate the novel process of the present invention for drying engraving a sheet of paper material, while FIGS. 1 to 9 show apparatus for carrying out the improved process in accordance with the sequence of steps shown schematically in FIGS. 10 to 13.
Initially, a sheet of material from a source of supply thereof comprising a stack of sheets if moved to a foil stamping station broadly designated B in FIG. 14 whereupon flat stamping die 20 having a raised letter or design defining section 22 projecting from the lower face 24 thereof is provided for impressing foil onto the upper surface of the sheet of paper 26 when die 20 is shifted toward the backup platen structure 28 through a displacement to force the foil strip 30 into contact with the upper face of sheet 26. It is to be understood in this connection that the foil strip 30 conventionally comprises a synthetic resin backing sheet comprising polyethylene terephthalate (sold under the trademark MYLAR by E. l. DuPont De Nemours & Co., Inc., of Wilmington, Delaware) supporting a pigment composition which generally includes a metallic constituent, pigments and binding agents along with an adhesive material for assuring firm adherence of the layer of foil deposited on the paper from the Mylar backing material when heat and pressure are placed on the foil strip while the pigment metallic layer thereof is maintained in contact with the paper to which the foil layer is to be applied. In the schematic illustrations of FIGS. 14 to 17, the Mylar backing has not been illustrated and only the pigment layer has been shown for purposes of clarity.
FIG. 15 illustrates the paper sheet 26 having a foil impression 30a thereon which conforms to the design defined by the flat, outer face 22a of stamping die 20. Although the impression 300 has been shown for clarity as standing above the surface of paper 26 to a certain extent, in fact the impression will be below the surface of the paper because of the pressure applied to the foil during stamping thereof. By virtue of the fact that the die 20 is heated, the impression 30a transferred to paper 26 very closely conforms to the configuration of face 220, and the adhesive in the foil 30 causes the same to firmly adhere to the upper face of sheet 26. Next, the impressed sheet 26 is shifted to an embossing station C where an em-' bossing die 32 having a design defining cavity 320 therein in exact registration with impression 30a is moved toward backup counter structure 34 so that the raised area 34a of counter 34 mates with depression 32a to effect embossment of the section 26a of paper sheet 26. The final product is shown in FIG. 17 wherein it can be seen that the embossed section 26a of the sheet 26 is of slightly greater width than the transverse dimension of the foil impression 30a. The sheet thus dry engraved has an appearance closely simulating a wet engraved sheet and permits production of designs of substantially greater intricacy than is possible with wet engraving processes. Preferred mechanism 36 for shifting sheets of paper 26 from a supply thereof to the stamping and embossing stations B and C of a press 38 includes as its primary components a vacuum operated shuttle bar conveying unit 40 for gripping and shifting the sheets successively into and out of the stations B and C, as well as apparatus 42 for reciprocating the shuttle bars and for bringing a vacuum source into communication with the bars in timed relationship to the reciprocation thereof.
The press 38 has a stand 44 carrying an L-shaped frame member 46 which supports a lower, generally horizontal bolster plate 48 which in turn, carries lower die set structure 50 directly below upper die set structure 52 suspended from the ram 54 of the press, Viewing FIG. 2 wherein the upper die set structure 52 and ram mechanism of the press is removed for clarity, it is to be noted that a flat backup platen 28 is located at station B, while a counter 34 is located at station C on structure 50. In FIG. 1 it is to be seen that the upper die set 56 of structure 52 mounts stamping die 20 thereon directly above platen 28 while the upper die set 58 of structure 52 carries embossing die 32 thereon in vertical alignment with counter 34. The upper die sets 56 and 58 carrying stamping die 20 and embossing die 32 thereon are thus simultaneously movable toward and away from the backup structure 50 mounting platen 28 and counter 34.
The lower main frame 60 of conveying mechanism 36 upright, inverted J-shaped support 64 carried by frame 60 as well as by a bracket 66 of L-shaped transverse configuration having a gusset 68 thereon. Adjustable foot structure 70 carrying frame 60 atthe corners thereof, as well as below frame support 64, permit leveling of conveying unit to maintain the. same horizontal in alignment with platen 28 and counter 34 on lower die set structure 50. Preferably, bracket 66 is firmly'affixed to the proximal end of lower die set structure to prevent relative movement between mechanism 36 and press 38. Further, parts of the conveying unit 40 are rigidly fixed to lower die set 50 adjacent station B, and the lower frame may also be joined to the lower part of stand 44 if additional rigidification of the components is necessary under .iigh speed operating parameters.
Bracket 72 (FIGS. 1, 2, and 3) carried by the front face of main plate 62 has a horizontal plate 72a which supports an upright member 74 in spaced relationshipfrom the proximal surface of main plate 62 and held. in place by a pair of triangular gussets 74a between members 74 and plate 72a. Shaft 76 carried by main plate 62 and upright member 74 supports a sleeve 78 rotatable thereon which, in turn, mounts a pair of triangular rocker plate elements 80 and 82 in horizontally spaced relationship forwardly from main plate 62 as is best shown in FIGS. 1 and 3. 1 1
Means for oscillating the plate elements 80 and 82 includes an electric motor 84 on the rear portion of frame 60 which is connected to a clutch and brake unit 86 and is operably coupled' by coupling 88 through a gear reducer 90 and an intermediate coupling'9l therebetweenl The output of unit 86 is joined to' shaft 92 extending through main plate 62 and carried by bracket support 94. I
A crank andsleeve assembly 96 joined to shaft 92 (FIGS. 1 and 3) isoperably coupled to the plates 80 and 82 by a connector assembly 98. The elongated main coupler 100 of connector assembly 98 has upper and lower openings 102 and 104 therein along with axially aligned openings (not shown) extending along the longitudinal axis of the same in communication with openings 102 and 104." The lower bearing unit 106 pivotally pinned to the end of crank arm 96a remote from shaft 92, has'an extension 108 thereon extending through the lower end of coupler I00 and into the passage therethrough between openings 102 and 104. Coil spring 110 around extension 108 between spacers 112 on extension 108 within opening 104 and theportion of coupler member 100 defining the top of opening 104, serves to bias the coupler member 100 away from bearing 106. Similarly, a bearing-114 pivotally connected to plate elements .80 and 82 by a shaft 116 therebetween hasan extension 118 projecting into the opening 102 in coupler member l 00 so that the spring 120 surrounding extension 118 within opening 102 and bearing against spacer structure 122, as well as the end of coupler member 100 defined by opening 102 in proximal relationship to bearing 114, serves to bias the latter toward coupler member 100.
During rotation of the crank arm 96a in a counterclockwise direction viewing FIG. 1, the plate elements 80 and 82 are oscillated through an arc limited by adjustable stop assemblies 124 and 126 carried by plate 62 on opposite sides of bracket 72. Each stop 124 and 126 includes a bolt threadably received within the bracket of a corresponding stop in disposition such that the head of each bolt 128 engages the resilient heads of blocks 130 and 132 respectively carried between opposed faces of plate'elements 80 and 82.
Shuttle bar conveying unit 40 includes outer reciprocable bars 134 and 136 on opposite sides of a stationary bar 138. Each bar has a longitudinally extending passage 140 therethrough communicating with a nipple 142 at respective ends thereof overlying mechanism 36. For simplicity of manufacture, thepassages 140 are preferably milled in the upper faces of respectivebars 134, 136 and 138, and the grooves therein then closed by respective upper plates 144, each having a series of strategically located vacuum ports 146 therein as will be explained in greater detail hereinafter. The central bar 138 is rigidly mounted on lower die set structure 50 by spaced blocks 148 and 148a. Each of the reciprocable bars 134 and 136 is provided with two elongated, longitudinally spaced, flange defining strips 150 which project beyond opposed, upright side margins of corresponding bars 134 and 136 (FIGS. 1, 4 and 5-7) while a second strip 152 is secured to bars 134 and 136 in underlying relationship to strips 150 with each strip 152 being of approximately the same width as the corresponding bar thereabove. The strips l 52 are coextensive in length with strips 150.
Spaced supports 154 and 156 reciprocably carry shuttle bar components 134 and 136 (FIG. 1). The right-hand corner of lower die set structure 50 viewing FIG. 2 has a notch 50a therein for clearing structure 154 and the adjacent end of main plate 62, while the forward edge 50b of structure 50 has a rectangular notch 50c therein which received structure 156. Referring first to the support structure 154 above rocker elements 80 and 82, an irregularly shaped plate 158 is carried in spaced relationship by the upper end of main plate 62 from the outer front face thereof by three spacer bolt and sleeve assemblies 160. The space between plate 158' and main plate 62 is slightly greater than the horizontal space occupied by bars 134, 136 and 138 as is best evident from FIGS. 2 and 4. Bosses 162 and 164 on plates 158 and 62 respectively (FIG. 4) carry a fixed shaft 166 which supports two rollers 168 and 170 each provided with an irregularly shaped groove 172 therein adapted to complementally mate with the bottom surface of corresponding bars 134 and 136. as defined by strips 150 and 152 thereon. Plate 174 secured to the right-hand end of outer plate 158 viewing FIG. 1, and to main plate 62 within notch 62a therein has horizontally spaced notches 174a in the upper margin thereof for'clearingbars 134 and 136 during reciprocation thereof. The L-shaped retainer 176 mounted on plate 174 intermediate the ends thereof has notches 176a in the upright leg thereof in opposite side margins for receiving proximal edges of strip 150 whereby the upper opposed, outwardly projecting ears defined by the upper section above notches 176a serve to prevent vertical movement of the right-hand ends of bars 134 and 136 vertically away from rollers 168 and 170. Inverted L-shaped retainers 178 bolted to oppositely facing vertical surfaces of plate 158 and the rear face of main plate 62 have inwardly directed segments which overlie the outwardly projecting portions of strips 150 on corresponding bars 134 and 136 to cooperate with the retainer 176 in precluding movement of bars 134 and 136away from rollers 168 and 170.
Structure 156 includes an outer rectangular plate 180 secured by fasteners 182 to the edge 50b of lower die set structure 50 on opposite sides of notch 50c therein. An inner plate 184 having an inwardly facinghorizontal notch 184a in the top edge thereof is connected to outer plate 180 and is maintained in spaced relationship-therefore by a cross plate 188 adjacent the left-hand margin of structure 156 viewing FIG. 1, as well as by a cross plate 190 at the opposite end of structure 156. Fasteners 18,6 join plate 180 to cross plates 188 and 190 as well as an inner plate 181 located between proximal upright edges of plates 188 and 190 and the inner face of plate 180, while suitable inner connectors (not shown) couple inner plate 184 to the inner margins of cross plates 188 and 190.
The cross plate 188 has opposed notches 188a therein for clearing shuttle bar components 134 and 136 as shown in FIG.
7, with the central, upstanding portion of 'plate 188 serving as means for mounting an L-shaped retainer192 of the same configuration as retainer 176 and thereby serving to hold down the inner edges of bars l34 and 136-Two rollers 194 and 196 underlying shuttle bars 134 and 136 respectively, and of the same grooved configuration. as rollers 168 and 170, are carried by a cross shaft 198 between plate 181 and inner plate 184.
Plate 184 carries an L-shaped retainer 200 thereon provided with an upright base section of greater width than the horizontal crosspiece thereof and as is apparent from FIGS. 2 and 7, retainer 200 is secured to plate 184 within notch 1840 in disposition such that the horizontal crosspiece of the retainer overlies the outwardly projecting lip defined by the proximal strip 150 of bar 136. Another L-shaped retainer 202 mounted on the upstanding integral lug 181a of plate 181 overlies the proximal margin of strip 150 on bar 134. Retainer 200 is held on plate 184 by fasteners 204, while fasteners 206 secure retainer 202 on lug 181a.
Cable structure is provided for coupling reciprocable bars 134 and 136 to plates 80 and 82 respectively. Included in such structure are a pair of double-groove sheaves 208 and 210 rotatably mounted on a fixed shaft 212 between bosses 214 and 216 on the outer face of plate 158 and the rear face of main plate 62 respectively in alignment with rollers 168 and 170 respectively. Another pair of double-groove sheaves 218 and 220 are rotatably carried by a fixed shaft 222 mounted in bosses 224 and 226 on plates 158 and 62 below bosses 214 and 216 (FIGS. 1 and 4) in alignment with sheaves 208 and 210. The plates 80 and 82 have curved caps 228 thereon. As is shown in FIG. 4, the spacing between plates 80 and 82 is equal to the space between'sheaves 208 and 210 as well as sheaves 218 and 220 so that the plates are maintained in vertical alignment with respective bars 134 and 136. Cable means for operably joining plate 80 to its corresponding bar 134 includes a first flexible cable 230 joined to the left-hand margin of plate 80 by connector unit 232, extends over the cap 228 within a corresponding groove 228a, then passes over the aligned sheave 218 on the right-hand side thereof viewing FIG. 8, thence under and over the sheave 208 thereabove about the left-hand stretch thereof as shown in FIG. 8, and finally, beneath the front bar 134 where it is connected to the righthand margin thereof by a connector 234.
Another flexible cable 236 joined to the right-hand margin of plate 80 as shown in FIG. 1, by an adjustably connector 238, passes across the corresponding cap 228 within a groove 228b therein and then extends under sheave 218 on the lefthand side thereof as indicated in FIG. 8, thence around sheave 208 on the right-hand side of the same for connection to the bottom margin of front bar 134 by a connector 240 located between proximal spaced ends of strips 150 and 152.
A similar cable arrangement is provided for operating the back bar 136. In this instance, a flexible cable 242 connected to the left-hand margin of plate 82 by connector 244 extends across a groove228c in the corresponding cap 228 and is then trained around the right-hand portion of the sheave 220 as shown in FIG. 8, continues upwardly around the right-hand portion of sheave 210 and is joined to the lower part of bar 136 intermediate the ends of the latter by a connector 246 also located between proximal spaced extremities of strips 150 and 152 on bar 136. The second flexible cable 248 on plate 82 is joined by an adjustable connector 250 on the right-hand margin of the plate as shown in FIG. 8, passes over the corresponding cap 228 within groove 228d therein, and is trained under sheave 220 on he left side thereof, extends upwardly over the left-hand portion of sheave 210, and is then coupled to the forwardmost end of back bar 136 by a coupling 252.
Although not specifically shown in physical form in the drawings, it is to be understood that a vacuum source 254 (FIG. 9) is provided in association with mechanism 36 and having three vacuum lines 256, 258 and 260 respectively, connected thereto, as well as the nipples 142 of corresponding shuttle bars 136, 138 and 134 respectively. Solenoid actuated valves 262, 264 and 266 in the lines 256, 258 and 260 are each operated by a vacuum control unit 268 which is in part actuated by two pairs of electrical switches 270 and 272 respectively, mounted on main plate 62 (FIG. 1) in disposition to be actuated by plates 80 and 82. Although not illustrated, the control unit 268 also includes cam operated means for actuating solenoid 264 in timed relationship to the actuation of solenoids 262 and 266.
In the preparation of a dry engraved greeting card or other item which would normally be subjected to wet engraving, the
artist initially prepares a design representing the letters or artistic indicia to be imprinted on the sheet of paper material. This line drawing by the artist is then transferred by conventional photographic techniques to a copper plate which is then etched in a manner to produce a duplicate of the desired flat stamping die wherein raised areas are presented conforming to the artist's design. The outer faces of these raised areas are essentially flat. A copper or nickel reverse mandrel is electroformed against the etched copper original and the back of the electroform in then reinforced with glass fiber reinforced epoxy resin. The supported mandrel is removed from the copper original and the front face of the released mandrel coated with precipitated silver or other electrically conductive solution which acts as a parting agent. A nickel duplicate of the original etched copper plate is electroformed into the mandrel, removed from the copper original and then joined to a steel backing plate after filling of the reverse intaglio face of the electroform. This electroformed die plate is a duplicate of the original etched copper member and comprises the flat stamping die 20 usable on press 38. By making a copper original as described, an exact reproduction of the artwork may be prepared and any number of nickel duplicates prepared therefrom. The use of an etching technique to prepare the copper duplicate has the advantage of forming raised areas wherein the sidewall defining margins thereof are relatively vertical so that the outline of the design presenting raised sections terminate in very sharp edges for more effective cutting of the desired design from the foil strip during the foil stamping step of the present method.
The embossing die 32 is prepared by photographically depositing the design image on a Zomag plate (an alloy of zinc and magnesium) whereupon the engraving artist forms depressions in the alloy of such depth as he deems most effective in presenting a three-dimensional design in the paper of most desirable three-dimensional effect. As will be explained, the transverse dimensions of the impressions in the embossing die should be somewhat wider than the foil impression placed on the sheet of material 26. This difference may be accomplished either by making the depressions in the embossing die somewhat larger than the original artwork or as an obvious alternative, producing a flat stamping die wherein the raised section 22 is of somewhat less width than the original artist's design. AFter preparation of the Zomag original, a duplicate thereof is prepared by conventional techniques such as electroforming of a copper reverse thereagainst followed by electroforming of a nickel duplicate of the copper reverse which may then be mounted on a backing plate after filling of the rear intaglio surface of the nickel duplicate.
The image defining section 22 of the flat stamping die 20 may be made thinner than the original artwork by preparing a photographic positive from an original negative of the artist's drawing. The positive is placed over clear film sheets above an emulsion film whereby the undercoating caused by exposure of the emulsion to a greater extend than the width of the original negative, makes the final image produced in the photographic film upon development thereof to be thinner than the artist's original. If this thinner positive is then used to produce the flat stamping die 20, the design presenting raised section 22 thereof will be of less effective width than the original artwork by the artist.
On the other hand, if it is desired to make the cavities 32a in embossing die 32 of greater width than the artist's original design, this may be accomplished by placing an original negative of the art over a photographic film separated from the negative by clear spacers and exposed under a 15 watt bulb through a yellow filter. The result in this case is production of a negative wherein the lines therein are thicker than the original artwork. Whichever technique is used, it is to be pointed out though that the cavity 32a in embossing die 32 should be of greater transverse width than the effective width of the corresponding portion of raised section 22 of flat stamping die 20. Preparation of a counter 34 from embossing die 32 assures that a paper sheet 26 processed in the novel apparatus of this invention will be embossed to a greater width than the foil impression 30a placed on paper sheet 26.
After preparation of a suitable flat stamping die and an embossing die 32 therefor, necessary components, along with the backup structure 28 and 34, are placed on the lower die set 50 of press 38-at the stations designated B and C thereon.
. As illustrated in FIG. 10, an initial sheet 1 of a stack to be processed is located at station A in disposition to be received on the upper face of bar 136 which is, located in its leftmost position at the time that bar 134 isat the right-hand end of its path of travel. This is the disposition of the parts as shown in FIGS. 1 to 9 inclusive. At that instant in the operation of the mechanism, the block 132 between plates 80 and 82 is in engagement with bolt 128 of stop 126 and the switches 272 are actuated by plates 80 and 82 to cause valve 262 to be energized and valve 266 to be de-energized, In this manner the vacuum source 254 is brought into communication with the ports 146 in back bar 136 via passage 140 therein, while the ports 146 in front bar 134 are closed from communication with vacuum source 254. In this connection it is to be seen that each of the bars134, 136 and 138 is provided with three pairs of ports 146 therein with each pair separated in longitudinally spaced relationship a distance such that when a sheet of paper overlies one pair of ports, an adjacent sheet will overlie the proximal pair of ports without overlapping of the paper. Communication of the ports' 146 of back bar 136 causes the sheet 1 to be drawn against the upper face of plate 144 on back bar 134 so that the sheet will be moved with the bar 136 during reciprocation thereof.
Oscillation of the plates 80 and 82 in a direction toward stop 125 is effected by operationof motor 84in a direction to rotate crank and sleeve assembly-96 in a counterclockwise direction viewing FIG. 1 via the gear and coupling train shown in FIG. 4 whereby the plates 80 and 82 are rotated in a counterclockwise direction through the connector assembly 98. As the plates 80 and 82 rotate counterclockwise, the front bar 134 is shifted to the left by cables 230 and 236, while the back bar 136 is moved linearly in the opposite direction by cables 242 and 248. As is apparent in FIG. 8, when plate 80 moves to the left, cable 230 pulls the front bar 134 toward the left, while an opposite pull is placed on back bar 136 by cable 242 secured to plate 82.
Bars 134 and 136 are restricted to rectilinear paths of travel by roller 168 and 170 at the right-hand side of the mechanism 36 viewing FIG. 1, as well as by the rollers 194 and 196 of structure 156. Ba r'138 is stationary during reciprocation of front and back bars 134 and 136.
As the bar 136 commences to move to the right, viewing FIGS. 8 and 10, the sheet 1 gripped by the left-hand end of the bar is moved toward station B as illustrated in FIGS. 2 and 11 in direct underlying relationship to flat stamping die 20. When plates 80 and 82 reach the left end of their paths of travel as illustrated in FIG. 1, the path of arcuate movement of the plates is limited by bolt 128 of stop 124 whereupon bars 134 and 136 cease reciprocation in respective directions of travel. In order to assure positive stopping of sheet 1 in direct underlying relationship to the foil stamping die 20 at station B, the stop bolt 128 is positioned such that arcuate movement of plates 80 and 82 is interrupted before crank 96 has rotated through an angular path of travel where the pivot of bearing 106 has passed over center relative to the axis of rotation of shaft 92. However, the crank arm 96 may continue rotation in a counterclockwise direction by virtue of the movement of coupler 100 longitudinally of the extension 118 connected to bearing 114 against the action of spring 120 bearing against spacer structure 122. During this small period of dwell provided by further rotation of crank arm 96 as plateelements 80 and 82 rest against the stop 124 under the bias-of spring 120, the ram 54 of press 38 is actuated to bring the stamping die 20 into engagement with a strip of foil interposed between face 22a of die 20 and paper sheet 1 at station B. The foil strip is preferably in the from of a web which is supplied from a roll thereof and intermittently moved in association with shifting of paper sheets 60 and in timed relationship thereto so that a fresh portion of the foil strip is always presented to stamping die 20 upon reciprocation thereof. Since the foil strip comprises a metal powder, pigment or combination thereof deposited on a synthetic resin backup sheet, the backup stretch may simply be rolled upon a takeup spool as the foil strip is intermittently shifted. In any event, as previously explained, the flat stamping die 20 is suitably heated, as for example, with resistance heating wires either embedded therein or provided on the upper die set structure 52 whereby, when the hot raised design defining section 22 of die 20 is brought into engagement with the foil strip 30 and then forced toward backup platen 28 under considerable pressure, an impression 30a of foil is caused to adhere to the upper face of the sheet 1 supported by backup platen 28. Because of the pressure on the paper by flat stamping die 20, the foil impression 30a is actually forced into the surface of the paper and lies slightly below the initial planar face of the paper sheet 26. However, the foil impression 30a very accurately conforms to the configuration of the design presented by raised section 22.
During the downward stroke of the flat stamping die 20 which occurs simultaneously with the dwell of plates and 82 against stop 124, the switches 272 are engaged and actuated, one of which causes valve 262 to be de-energized, while the other causes valve 266 to be energized. At that instant, sufficient vacuum pressure remalns in passage of back bar 136 and sufficient vacuum pressure is effected in passage 140 of front bar 134 so that the sheet 1 at station B is held in position by both the back bar 136 and front bar 134. Also at that instant, the ports 146 of stationary bar 138 which may be regulated by the switches 270 and 272 or an independent timing device (not shown) connected to vacuum control 268, are brought into communication with the vacuum source 254 through line 258 by the energizing of valve 264. Accordingly, the sheet 1 at station B is also held on stationary bar 138 as well as on the front and back bars 134 and 136 respectively.
As the plates 80 and 82 begin their travel away from stop 124 and toward stop 126, valve 264 is de-energized to block communication of the ports 146 of stationary bar 138 with vacuum source 254. Simultaneously, a sheet 2 from the stack at station A is gripped by the ports 146 on from bar 134 for shifting to station B, and the sheet 1 at station B is carried on front bar 134 to station C as back bar 136 returns from its right-hand end of travel to its leftmost end. As the plates 80 and 82 once again engage stop 126 and actuate the switches 272, upper die set 52 is moving downwardly toward lower die set 50. The actuation of switches 272 during the dwell of 7 plates 80 and 82 against stop 126 causes communication of the ports 146 in back bar 136=with vacuum source 254 and blocks communication of the ports 146 in front bar 134 with source 254 in the manner as above described. Also at this instant, the ports 146 of stationary bar 138 communicate with vacuum source 254. Thus, sheet 2 is firmly held on bars 134-138 at station B for die stamping thereof at the same time that sheet 1 is firmly held on bars 134-138 at station C for em bossing of the foil design impression thereon (FIG. 12). Simultaneously, a sheet 3 from the stack at station A is gripped on back bar 136 to begin its processing run between the die sets 50 and 52.
As the plates 80 and 82 begin their travel-away from stop 124 and toward stop 126, valve 264 is de-energized to block communication of the ports 146 of stationary bar 138 with vacuum source 254. Simultaneously, a sheet 2 from the stack at station A is gripped by the ports 146 on front bar 134 for shifting to station B, and the sheet 1 at station B is carried on front bar 134 to station C as back bar 136 returns from its right-hand end of travel to its leftmost end. As the plates 80 and 82 once again engage stop 126 and actuate the switches 272, upper die set 52 is moving downwardly toward lower die set 50. The actuation of switches 272 during the dwell of plates 80 and 82 against stop 126 causes communication of the ports 146 in back bar 136 with vacuum source 254 and blocks communication of the ports 146 in front bar 134 with source 254 in the manner as above described. Also at this instant, the ports 146 of stationary bar 138 communicate with vacuum source 254. Thus, sheet 2 is firmly held on bars 134-138 at station E for die stamping thereof at the same time that sheet 1 is firmly held on bars 134-138 at station C for embossing the foil design impression thereon (FIG. 12). Simultaneously, a sheet 3 from the stack at station A is gripped on back bar 136 to begin its processing run between the die sets 50 and 52.
As the plates 80 and 82 begin their counterclockwise rotation toward stop 124, upper die set 52 is raised, vacuum pressure to stationary bar 138 is blocked, and back bar 136 travels towards its right-hand limit while the front bar 134 travels toward its left-hand limit of travel. Since vacuum pressure is maintained through the ports 146 of back bar 136 the sheet 1 is shifted to delivery station D, while the sheet 2 is shifted to embossing station C, and the sheet 3 is shifted to die stamping station B. When the switches 270 are engaged and during the :lwell of plates 80 and 82 in that position vacuum pressure through back bar 136 is blocked while pressure in front bar 134 and stationary 138 is initiated thereby simultaneously causing a sheet 4 from the stack of station A to be gripped on front bar 134, the sheet 3 at station 8 to be firmly held for die stamping thereof, the sheet 2 at station C to be firmly held for embossing thereof, and the sheet 1 at station D to be in position for delivery thereof. Subsequent clockwise rotation of plates 80 and 82 toward the stop 126 initiates a new cycle through stations A-D as above described.
It may be appreciated that the novel method and apparatus as above described provide a fast and efficient means for simulating the extremely expensive engraving process. Maintaining exact control over the cards or sheets as they are processed through the subsequent stations in the dry engraving operation assures that artwork of high aesthetic quality is obtained as exact registration of the foil stamped impression and areas of embossment thereunder is maintained. Further, the ability to produce a foil impressed layer of slightly narrower width than the embossed areas thereunder enhances the quality of the artwork to a degree which heretofore has not been attainable with processes other than wet engraving.
Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:
1. In a machine for dry engraving sheet material and provided with first and second pairs of spaced, opposed, relatively movable die set supports, anddrive means for periodically moving said first pair of die set supports into proximal working relationship and for periodically moving said second pair of set supports into proximal working relationship, there being means for supplying a strip of foil between said first pair of die set supports, the combination with said machine of:
stamping structure on at least one of said die set supports of said first pair thereof and including raised areas conforming to a specific design;
an embossing assembly on said second pair of die set supports and provided with opposed, mutually cooperable raised and depressed embossing sections carried by said opposed die set supports of said second pair and conforming to at least a part ofsaid design; and
mechanism including shiftable means operable to engage a sheet of said material and sequentially shift the sheet into a first stationary position between said first pair of die set supports and aligned with said structure, said sheet engaging means being operable to hold the sheet stationary in said first position while said drive means moves said first pair of die set supports into said working relationship to cause a layer of foil to be impressed on the sheet from the strip thereof by said structure and conforming to said design,
said sheet engaging means then being shiftable without releasing the sheet to shift the latter into a second stationary position between said second pair of die set supports and with said layer of foil impressed on the sheet exactly aligned with said sections of the assembly, said sheet engaging means being operable to hold the sheet stationary in said second position while said drive means moves said second pair of die set supports into said working relationship thereof to emboss the sheet in precise alignment with said layer of foil impressed thereon,
the embossing sections of the embossing assembly being greater in width than said raised areas of the stamping structure, the raised areas thereby being operable to impress portions of said foil layer which are narrower than corresponding underlying embossed portions of said sheet.
2. A machine as set forth in claim 1, wherein said mechanism includes a conveying unit adjacent said structure and the assembly provided with a pair of shiftable components disposed to receive a sheet thereon, apparatus operably coupled to the component for shifting the same relatively, and actuatable means cooperable with the components for causing the sheet to be gripped and held on one of the components for shifting of the sheet from a remote location to said first position and to thereafter cause the sheet to be gripped and held on the other component for moving the sheet to said second position.
3. A machine as set forth in claim 2, wherein said components and the actuatable means are operable to alternately pick up a sheet from said remote location and successively shift the sheet to said one position.
4. A machine as set forth in claim 3, wherein said components and the actuatable means are alternately operable to shift a sheet from said one position to the second position.
5. A machine as set forth in claim 2, wherein said components and the actuatable means are operable to simultaneously deliver a sheet to the first position from said remote location while conveying a sheet from the first position to the second position and a sheet from the second position to a delivery position.
6. A machine as set forth in claim 2, wherein said pair of components are each provided with at least one vacuum port, vacuum pump means operably communicating with the ports in said components and means operably associated with the pump means and said port for controlling communication of the ports of respective components with the pump means.
7. A machine as set forth in claim 6, wherein said pair of components are mounted for reciprocation in opposite directions, each of the components being provided with a plurality of said vacuum ports spaced in the direction of said reciprocation at intervals corresponding to the distance between said structure and said assembly.
8. A machine as set forth in claim 7, wherein is provided vacuum lines communicating the pump means with the ports of each component respectively, valve means in each of said vacuum lines, and a control unit operably associated with said valve means for alternately opening and closing the valve means of said components respectively to effect the gripping of a sheet on said one component during shifting from said remote location to said first position, simultaneous gripping and holding of the sheet on said one component and said other component during die stamping of the sheet, release of the sheet from said one component and holding of the same on the other component during movement thereof to said second position, and thereafter simultaneous gripping and holding of the sheet on said other component and said one component during embossing of the sheet.
9. A machine as set forth in claim 8, wherein said conveying unit includes a stationary component disposed between said pair of shiftable components andhaving a pair of vacuum ports therein spaced in alignment with said structure and said assembly and periodically communicating with said pump means and said ports in the stationary component for effecting communication of the ports in said stationary component with said pump means during die stamping and embossing of a sheet.
10. A machine as set forth in claim 7, wherein said apparatus includes a prime mover having a rotary shaft, a rocker 11. A machine as set forth in claim 10, wherein is provided means engageable with said rocker element at each of said limits respectively for actuating said control unit to effect said alternate opening and closing of the valve means in said vacuum lines.