US3122150A - Etching machine - Google Patents

Description

Feb. 25, 1964 T. HENDERSON 3,122,150

E'I'CHING MACHINE Filed Aug. 3, 1962 8 Sheets-Sheet 1 F l G.- I

fig

- INVENTOR. THOMAS HENDERSON T MO RGAN,FINNEGAN, DURHAM a PINE ATTORNEYS T. HENDERSON ETCHING MACHINE Feb. 25, 1964 8 Sheets-Sheet 2 Filed Aug. 5, 1962 T0 FIG. 2A

THOMAS HENDERSON MORGAN, FINNEGAN,DURHAM 8 PINE ATTORNEYS Feb. 25, 1964 T. HENDERSON 3,122,150

ETCHING MACHINE Filed Aug. 3, 1962 8 Sheets-Sheet 3 INVENTOR.

THOMAS HENDERSON MORGAN, FINNEGAN,DURHAM 8 PINE ATTORNEYS T. HENDERSON Feb. 25, 1964 ETCHING MACHINE 8 Sheets-Sheet 4 Filed Aug. 3, 1962 FlG.-6

FlG.-5

INVENTOR.

THOMAS HENDERSON BY MORGAN, FINNEGAN, DURHAM 6 PINE ATTORNEYS Feb. 25, 1964 1-. HENDERSON 3,122,150

ETCHING MACHINE Filed Aug. 3, 1962 8 Sheets-Sheet 5 INVENTOR.

THOMAS HENDERSON BY MQRGAN, FINNEGAN,DURHAM B PINE ATTORNEYS Feb. 25 964 Filed Aug. 1962 T. HEN D SON ETCHING MACHINE 8 Sheecs eelc 6 INV TOR THOMAS HEND SON BY MORGAN, FINNEGAN,DURHAM 8 PINE ATTO E"s Feb. 25, 1964 HE ND ERSQN I 3,122,150

ETCHING MACHINE Filed Aug. 5, 1962 a Sheets-Sheet 7 XIV I INVENTOR.

THOMAS nsuneason MORGAN,FINNEGAN,DURHAM & PINE ATTORNEY S Feb. 25, 1964 -r. HENDERSON 3,122,150

ETCHING MACHINE Filed Aug. 3, 1962 8 Sheets-Sheet 8 AAA HEAD MOTOR mas oo A f SPLASH TIMER MOTOR |30A 13s TIMER I INVENTOR.

THOMAS HENDERSON BY MORGAN, FINNEGAN, DURHAM 8 PINE ATTORNEYS United States Patent Ofifi ce 3,122,150 Patented Feb. 25, 1964 3,122,150 ETCHIN G MACHINE Thomas Henderson, Locust Valley, N.Y., assignor to Powers Chemco, Inc., Glen Cove, N.Y., a corporation of New York Filed Aug. 3, 1962, Ser. No. 214,691 Claims. (61. 134-58) The present invention relates to etching machines and, more particularly, to machines for etching metallic printing plates. The invention more particularly concerns an etching machine for etching arcuately-disposed printing plates.

Heretofore, plates for rotary printing presses, and other presses employing printing cylinders, Were etched fiat in the conventional etching machines. The etched plates, such as electrotype shells, were then secured to metallic backing pla.es which were curved to fit the press cylinder. In other instances, the etched plates themselves were curved onto the press cylinder. In each case, when a plate etched flat was applied to a curved member, such as a backing plate or the press cylinder, some stretching of the etched plate occurred due to a change in conformation. This stretching of the plate, it will be understood, adversely affected the etched image. Further, in color reproduction it was extremely difficult to obtain the proper registry of the plates, since there was no way to control this plate stretching, thus necessitating substantial manual refinishing of the etched plate.

Efforts to overcome this problem have included the attempt to etch the plates in an arcuate configuration. However, such attempts have been uniformly unsuccessful, since certain portions of the curved plate being etched persistently received a more sustained splashing of the etching mordant than other portions thereof, resulting in an undercut plate or a plate that exhibited a high degree of color or dot loss.

General Description The present invention is characterized by a novel plate support and drive mechanism which ensures uniform exposure of the arcuately disposed plate to the etching mordant. The plate to be etched is supported in curved disposition and spaced from the etchant bath. The plate is preferably suspended above the etchant and curved about a generally horizontal axis. The plate support drive means is operative to rotate the plate back and forth about its horizontal axis While simultaneously rotating the plate back and forth about a vertical axis. Thus, all portions of plate are substantially exposed equally to the splashing effect of the mordant, thereby ensuring the proper etching of the plate with a minimum of color loss.

In addition, this double rotational movement of the printing plate is effective to expose all sides of the printing image to the etchant, resulting in a uniform etch. Heretofore, the etchant, impinging against a curved plate did not contact all sides of the image, producing images that were non-uniformly etched.

Further, means is provided for adapting the plate support for handling cylin rical and semi-cylindrical plates, and flat plates, such as electrotype shells, which are curved into arcuate configuration to duplicate their ultimate printing disposition.

Also, in the present invention, there is provided an improved plate drive support cover and hood for the machine which saves machine headroom while permitting mounting of the machine flush against a wall, eliminating previously wasted floor space. The plate support inciudes a saddle or inverted U-shaped member suspended from the machine cover. The machine drive mechanism is carried on the top of the cover and the cover is mounted on a carriage arrangement for rolling movement back and forth from operative etching position to non-operative plate-loading position. A foldable hood covers the front of the machine during the etching operation. This arrangement of tank housing elements provides ready access to the plate mounts and replaces the upwardly pivoting machine cover and counterweight employed heretofore.

Another important feature of the present invention is the provision of means for accomplishing uniform peripheral speed for all sizes of cylindrical arcuate plates. The plate mounting means includes a pair of opposed, stepped mounting plates to accommodate the various sizes of cylindrical plates. An adjustable speed drive means is employed to rotate each of the various sized plates at a uniform peripheral speed to thus ensure a uniform exposure of the portion of the plate to be etched to the paddle splash.

Objects It is, therefore, the object of the present invention to provide an etching machine for etching printing plates to be used on printing cylinders.

A further object of the invention includes providing in an etching machine a novel work holder and drive mechanism for supporting plates to be etched in curved disposition and simultaneously rotating the plate about two transverse axes to expose all portions of the plate uniformly to the mordant.

Another object of this invention is to provide in a paddle-type etching machine, a novel work holder for supporting cylindrical and semi-cylindrically formed printing plates above the level of the etching bath and rotating the plate back and forth about its major horizontal axis while simultaneously rotating the plate about its minor vertical axis.

It is also an object of the invention to provide in an etching machine a novel work holder for simultaneously rotating an arcuately-disposed printing plate back and forth about its major and minor transverse axes, in excess of 360 in each direction to ensure complete exposure of all portions of said plate to said etching bath.

Another object of the invention is to provide a novel work holder mounting and support means including a rolling carriage for adapting said work holder for moving back and forth from operative etching position to nonoperative loading and unloading position.

A further object of the present invention is to provide means for effecting uniform peripheral speed of each arcuate plate etched.

An added object of the invention is the provision of adjustable drive means for the etched plates to effect uniform peripheral speed of each arcuate plate etched to ensure uniform exposure to the etching mordant.

Other objects and advantages of the invention will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims. 7 V

The foregoing general description and the following detailed description are exemplary and explanatory, but are not restrictive of the invention.

Gf the drawings illustrating, by way of example, a preferred embodiment of the invention wherein like numbers designate like parts:

FIG. 1 is a perspective view partly exploded of an etching machine embodying the present invention.

FIG. 2 is an exploded view of the plate drive mechanism.

FIG. 2A is a continuation of FIG. 2 at line 2A-2A,

FIG. 2.

FIG. 3 is a schematic view of the plate drive mechanism.

FIGS. 4-6 are detailed views of the top cover mounting means.

FIG. 7 is a plan view, partly in section of the machine illustrated in FIG. 1.

FIG. 8 is a detailed view of the saddle rotating means.

FIG. 9 is a sectional view taken along line 9, FIG. 7.

.FIG. 10 is a detailed view, partly broken, of the cylindrical plate mounting means.

FIG. 11 is a front view of the etching machine illustrating a cylindrical plate supported in the saddle.

FIG. =12 is a front view of the etching machine showing an alternative form of plate support means.

FIG. 13 is a sectional view taken along line 1313, FIG. 12.

FIG. 14 is a sectional view taken along line 1414, FIG. 12.

FIG. 15 is a sectional view taken along line 1515,

FIG. 13.

FIG. :16 is a detailed view of a plate holding member for the plate support means of FIG. 12.

FIG. 17 is a schematic wiring diagram for a suitable electrical control circuit for the invention.

Referring to the drawings, there is illustrated the preferred embodiment of the invention which includes an open tank 10 adapted to hold a suitable etching fluid. Tank 10 is provided with a cover housing 12, including a movable cover element 14 and hood '16, described more in detail hereinbelow.

To apply the etchant to the printing plate, tank 10 has a plurality of spaced rotatable splash paddles 18 which pick up the etchant solution in tank 10 and forcefully splash or impinge the solution against the printing plate during the etching operation. Paddles 18 are preferably driven by associated drive pulleys 19 from a drive belt 21. Suitable arrangements of paddles 18, pulleys 19, and belt 21, and associated operating mechanism are disclosed in my co-pending application S.N. 113,594, filed May 26, 1961. However, any other suitable means for driving paddles 18, such as disclosed in Guenst Patent 2,776,512 or Easley et al. Patent 2,669,048, may be employed without adverse effect.

A printing plate P, which may be formed of a suitable material, such as zinc, magnesium, copper, or even plastic, is supported in spaced relation above paddles .18 by a saddle or inverted U-shaped member 2-0 having a preferably horizontally-disposed element-22 and a pair of spaced downwardly depending arms 24 and 26. Arm 24 is provided with a horizontally-disposed rotatable hollow stub shaft 28 which is aligned in cooperating relationship with stub shaft 30, carried in suitable bearing block 32 in arm 26. The ends of shafts 2'8 and '36, disposed within saddle 20, are each provided with a transverse slot 34.

- To mount printing plate P in saddle 29 for rotation in tank 10 there is provided a suitable work mounting shaft 36 adapted to be received in the hollow ends of opposed stub shafts 28 and 30. Shaft 36 has, at each end thereof, a transverse pin 38 which fits snugly into slot 34 of its associated stub shaft, holding shaft 36 in generally horizontal disposition above paddles 18 in tank 10, as shown in FIG. 2.

To permit mounting of shaft 36 in operative plate supporting position, stud shaft 30 is freely supported in arm 26 for movement back and forth therein. When plate P on shaft 36 is to be mounted in saddle 20, shaft 30 is moved away from stud shaft 28. This allows one end of shaft 36 to be easily inserted into shaft 28 with pin 38 seated properly in its associated slot 34 on shaft 28. With shaft 36 so seated, stud shaft 36 is returned toward shaft 28 and into engagement with its associated end of shaft '36. The other pin 46' of shaft 36 is properly seated in slot 34 of shaft 39, and plate P is thus secured in proper position to be etched.

To ensure against inadvertent movement of shaft 30, there is provided a pivotable latch member 41, which is normally disposed against stop 42 and in the path of travel of shaft 30. Latch 41 limits movement of shaft 31} until pivoted away from stop 42 by the machine operator.

Drive Mechanism To rotate shaft 36 and plate P in tank *111, the end of stud shaft 28 passing through arm 24 and disposed on the side of arm 24, remote from shaft 36, is provided with a sprocket 4-4 driven by an endless chain 46. Chain 46, in turn, is trained about a drive sprocket 48 aflixed to one end of a shaft 50 supported in bearing block 52 on the underface of top member 22 of saddle 20.

The other end of shaft 50 has aifixed thereto a pinion 54- which is in meshing engagement with pinion 56 carried at one end of a vertical drive shaft 58. Shaft 58, in turn, is concentrically disposed within a hollow vertical tubular member 60 fixed to and supporting saddle 26.

Sleeve 66 passes through bearing housing 62 on support plate 64 mounted on cover element 14 and is provided at its end, remote from saddle 20, with a spur gear 66. Gear 66, in turn, is in meshing engagement with larger spur gear 68. It will be understood that rotation of spur gear 68 thus effects rotation of gear 66, and sleeve 60, rotating saddle 20 in the direction of the arrows A and B, FIG. 3.

To effect rotation thereof, gear 68 is axially mounted on one end of a drive shaft 70. The other end of shaft 70 is connected to a torque-limiting friction clutch 72 which effects a driving connection between shaft 70 and one end of an oscillating lever 74. The other end of lever 74- is pivotally connected to an end of-link 76, whose other end is pinned to crank arm 78.

Crank arm 78 is secured to and rotates with the output shaft 80 of angle gear unit 82. The input shaft 84 of gear unit 82, in turn, is connected to the output shaft 86 of a suitable non-reversible gear reduction motor 88. As shown best in FIG. 2, gear unit 82 and motor 88 are mounted on a support plate 90. Plate 90, at the end adjacent motor 88, is fixed directly to cover element 14 which the other end of plate 90 is secured to plate 64.

Shaft 58, axially disposed within sleeve 60, is rotatably accommodated in spur gear 66, passing through bearing housing 92 on another support plate 94. The end of V shaft 58, remote from saddle 20, is provided with a spur gear 96 in meshing engagement with spur gear 98 aflixed to a drive shaft 100. The lower end of shaft 100 is suitably seated in housing 92, while adjacent its upper end, shaft 16% is provided with a worm gear 102. A torque-limiting friction clutch 104 is connected with the upper extremity of shaft 100. Clutch 104 is preferably similar in construction and operation to clutch 72.

To rotate worm gear 102, there is provided in meshing engagement therewith a worm 106 connected at one end to the output shaft 168 of a suitable adjustable speed reversing motor 110. The other end of worm 106 is suitably supported in a bearing plate 112, fixed to hearing housing 92. Motor 110 is mounted on plate 94, in turn, secured at the end thereof adjacent motor 110 to plate 90. The other end of plate 94 is carried by support plate 64, as shown in FIG. 2.

It will be understood that actuation of motor 110 effects rotation of worm 1136, gear 104, shaft 160, gears 96 and 98 and, hence, shaft 58. Since shaft'58 is ultimately in driving relationship with stud shaft 28, rotation of shaft 58 rotates'shaft 36 and printing plate P in the directions of the arrows, C and D, FlG. 3. Motor can be replaced, if desired, by a direct current motor with an alternating current variable voltage.

Cover and Hood Cover housing 12 comprises a movable cover element 14 and a hood 16. Hood 16 includes three interhinged sections 114, 116 and 118. Section 114 is adapted to be normally aligned with cover element 14 and is hingedly connected to the leading edge of element 14 by hinge member 13. Sections 116 and 118 are adapted to be normally disposed in vertical relationship against the front of tank 10. Handle 120 facilitates pivotal movement of sections 114, 116 and 118 to provide access to tank 10.

To facilitate mounting or removal of plate P in saddle 20, cover element 14 is mounted for travel back and forth on tank 10 in the direction of arrows W, FIG. 1. Tank 10 is provided at each side thereof adjacent cover 14 with a track 120. Cover element 14 is mounted for travel along tracks 120 by means of a carriage-like arrangement including four vertically-disposed wheels 122, one of which is rotatably fixed to cover 14 at each corner thereof. Four horizontally-disposed casters 124, one adjacent each wheel 122, assist in adapting cover 14 for back and forth movement on tracks 120.

Electrical Control System FIG. 17 discloses a suitable schematic wiring diagram for controlling the various drive mechanisms of the subject invention. As disclosed in my aforementioned co-pending application S.N. 113,594, there is provided a constant, low-speed agitator motor 126 for maintaining the etchant bath in thoroughly mixed condition in tank 10. Likewise, there is provided a variable speed splash motor 128 for rotating paddles 18 at their etching speed. Timer motor 130 and timer motor switch 130A and relay 132 interconnect motors 126 and 128 to selectively actuate either motor 126 or motor 128. An agitator start-stop switch 134 and cover safety switch 136 may also be conveniently included.

In the present invention, motor 88 is electrically connected in parallel with splash motor 128 for simultaneous actuation therewith. Reversible motor 110 is also connected in parallel with motors 88 and 128. Timer motor 138 is provided for effecting reversal of motor 110 at the proper time in the sequence of machine operations. Timer motor 138 is a commercially available unit for controlling reversible motors such as motor 111). Timer earn 139 of motor 138 is in engagement at all times with either contact 149 or 142 of motor 110, as it rotates on timer shaft 137. This alternately effects rotation of motor 110 first in one direction and, then, in the opposite direction.

While the control system of FIG. 17 relates to the system disclosed in my aforementioned pending application, other systems can be employed with equal facility and without adverse effect.

Plate Mounting Means The present invention is adaptable for use with armate plates (generally called segments in the trade); cylindrical plates and flat plates which are eventually to be used on a curved printing cylinder. To mount these members on shaft 36, a variety of means is provided.

To mount plate cylinders 143, such as illustrated in FIG. 11, there is provided on shaft 36 a stepped end plate 144. Lock collar 146 limits axial displacement of plate 144 along shaft 36, while step 145 is adapted for positioning in contact with the inner periphery of the plate cylinder 1 .3. A pair of cooperating, stepped end plates 148 and 149 are provided for the opposite end of the plate cylinder 143. Plates 148 and 149 are preferably semicircular and spaced apart in plate cylinder 143 to form a center opening 159. A cap plate 6 152 is axially disposed on shaft 36 and provided with a pair of spaced wing bolts 153 and 154 threaded for travel in end plates 148 and 149, respectively. Cap 152 also includes spacer members 156 for engaging the edges 151 and 155 of plates 148 and 149 which define opening 150 and exerting radial pressure on plates 148 and 149 as cap 152 is urged thereagainst through wing bolts 153 and 154 and locked in position on shaft 36 by lock collar 158. The camming action of members 156 ensures that plates 148 and 149 will remain seated against the end of plate cylinder 143 during the etching operation.

To accommodate various diameters of plate cylinders 143, end plate 148 is provided with a plurality of steps 148A adapted to fit the standard sizes of plate cylinders. In like manner plate 144 includes a plurality of steps 145A to accommodate the other standard sizes of plate cylinders other than the size accommodated by steps 145.

When plate segments 160 are to be etched, end plates 144 and 148 are removed and replaced by a series of spaced annular supports 162, each comprising an annular shell 164 braced by cross-struts 166 and mounted concentrically on shaft 36, as shown in FIG. 12, and locked thereon by lock nut 168.

Each shell 164 is provided with two opposed circumferential slots 170 and 172 and two opposed longitudinal slots 174 and 176. Each slot, 178, 172, 174 and 176, is adapted to accommodate therein a locking member 178 comprising an inner plate 180 and an outer plate 182. Bolt 184 and wing nut 186 interconnect plates 180 and 182.

A segment 16%, is generally supported along the bottom portions of two, three, or four supports 162 depending on the size thereof. FIG. 12 illustrates a segment supported on three supports 162. It will be understood that the spacing between supports 162 corresponds substantially to the conventional lengths of printing segments.

Each longitudinal slot 174 and 176, adjacent the side edges 159 and 161 of segment 160, is provided with a locking element 178. Also, each circumferential slot 170, adjacent edges 159 and 161, is so provided with a locking member 178. Edges 159 and 161 are disposed between outer plate 182 of the locking element 178 and the outer face of shell 164, as shown in FIGS. 15 and 16. Wing nuts 186 are tightened firmly, clamping segment 168 against shell 164 during the etching operation.

Slot 172 is provided in the event two segments 160 are to be etched simultaneously. In such event, a second plate 166 is secured over the top of supports 162 with locking members 178 in longitudinal slots 174 and 176 being operative to clamp both segments 160 in common to its associated shell 164.

The foregoing are two convenient means for mounting arcuate printing plates for etching. Other means of mounting such plates may be employed without adverse effect.

Operation In operation, at the start of the etching operation, the machine operator folds sections 114, 116 and 118 of hood 16 back on each other to provide access to tank It). The appropriate etching mordant; such as, nitric acid, is placed in tank 10, together with any desired etching additives. It is desirable for the operator to depress switch 134 to effect complete dispersion and emulsiiication of the etching solution.

When plate P is ready to be etched, it is mounted on shaft 36 by means of end plates 144 and 148 or annular supports 162, as described hereinabove. With plate P secured in proper position on shaft 36, cover element 14 is rolled toward the front of tank 10 to move saddle 20 into position for easy access and mounting therein of plate P. Stud shaft 311 is then moved out of saddle 20 so that one end of shaft 36 can be readily inserted in shaft 28 and properly seated therein. Shaft 30 is now returned into seating engagement with the other end of shaft 36 and locked in such position by latch 40. Cover element 14 is moved away from the front of tank It? to the posit-ion shown in FIG. 1. Plate P is now ready for the etching operation.

To start the etching operation, hood 16 is returned to operative tank-covering position (see FIG. 1). This closes safety switch 136, completing a circuit energizing splash motor 128. Simultaneously, a circuit is completed actuating motors 88 and motor 110 through timer motor 138.

Upon actuation, motor 88 rotates its output shaft 86 to effect rotation of shaft 80 of unit 82. This, in turn, rotates crank arm 78, link 76, and lever 74 which, through clutch 72 and shaft 70, turns spur gear 68.

It will be understood that, because of the arrangement of crank arm 78, link 76, and lever 74-, spur gear 68 is rotated first in one direction and, then, in the opposite direction, even though output shaft 86 of motor 88 rotates continuously in the same direction.

The reversing rotation of gear 68 is transmitted to meshing gear 66 and, hence, to tubular shaft 58 and saddle 28 to rotate saddle 20 in the direction of the arrows E and F, FIG. 3.

To ensure complete randomness and non-uniform exposure of the plate P to the etchant, members 78, '76 and 7 are so dimensioned and arranged, and gears 66 and 68 are so proportioned, that the rotation back and forth of gear 68 effects rotation of gear 66 and saddle 20 somewhat more than one complete revolution in a particular direction.

Simultaneously, with the back and forth rotation of saddle 20 through motor 88, motor 110 and timer 138 are energized to rotate plate P. Energizing of motor 110 rotates its output shaft 108 and worm 106, which, in turn, effects rotation of worm gear 102, shaft 10% and spur gears 98 and 96. Since gear 96 is fixed to shaft 58, rotation of gear 96 turns shaft 58 which, in turn, turns shaft 50 through pinions 56 and 54. Rotation of shaft 5% is then transmitted through sprockets 43 and 44 and chain 46 to shafts 28 and 36 to rotate plate P back and forth in saddle 29.

It will be understood that as motor 110 is reversed through timer 138, its associated drive mechanism is also rotated first in one direction and, then, in the opposite direction to completely expose all portions to the etchant in tank 10. To ensure random, non-uniform plate exposure, gears 96 and 93 are so dimensioned and proportioned that rotation back and forth of gear 98 by motor 110 effects rotation of gear 96 and, hence, shaft 38 and plate P somewhat more than one complete revolution in a particular direction.

Motors 88 and 110 and their associated drive mechanisms remain actuated revolving saddle 20 and plate P back and forth in tank until the completion of the etching operation as determined by timer motor 13% When the etching operation is completed, timer 139, through relay 132, interrupts the circuit to motors 88, 119 and 128 while re-energizing motor 126. With the saddle 20 and plate P stopped, and the paddles 18 revolving at their slower agitating speed, the operator re-opens hood 16, slides cover element 14 toward the front of tank 10, and removes shaft 36 and etched plate P from saddle 20 until the next etching operation.

Thus, there is disclosed a simple, efiicient device for quickly and easily etching curved plates without the adverse eifects heretofore present. The random rotation of the plate to be etched co-acting with the random rotation of the plate support about an axis transverse to the plate rotation ensures overall non-uniform exposure of the plate to the etchant, minimizing the danger of undercutting.

What is claimed is:

1. In an etching machine for etching printing plates, the combination of a tank for holding a supply of etching fluid, means for vigorously applying said fluid against said plate -to be etched, means for enclosing said tank and fluid, a plate holder revolvably supported in said tank and disposed above the level of said fluid, means for ro-t tatably mounting at least one of said plates in said plate holder, and means for revolving said plate holder about a first axis and means for rotating said plate mounting means about a second axis angularly' related to said first axis.

2. The device as defined in claim 1, wherein said first and second axes are substantially transverse, and including means for effecting substantially simultaneous rotation of said plate holder and plate mounting means.

3. The device as defined in claim 1, including means for periodically reversing the direction of rotation of said plate holder and said plate mounting means during the etching operation.

4. An etching machine for etching printing plates comprising a tank for holding a supply of etching fluid, a plurality of elongated paddle members, means mounting said paddle members for rotation in said tank, operating means for rotating said paddles for splashing said etching fluid against said plates to be etched, housing members for enclosing said tank and fluid, a plate holder rotatably supported in said tank, and disposed above the level of said fluid, said plate holder being adapted to support said plates in a generally curved configuration, means for totatably mounting said plate in said plate holder, the axis of rotation of said plate holder being generally at right angles to the axis of rotation of said plate mounting means, means for effecting simultaneous rotation of said plate holder and said plate mounting means, and timing means for periodically reversing the direction of rotation of said plate holder and plate mounting means during the plateetching operation.

5. The invention as defined in claim 4, wherein said plate mounting means and said plate holder each rotate in excess of 360 before reversal.

6. The invention as defined in claim 4, including separate drive means for said plate holder and for said plate mounting means, and an electrical operating circuit interconnecting said separate drive means.

7. In an etching machine for etching arcuate printing plates, a combination of a tank for holding etching fluid paddles rotatably supported in said tank for impinging said fluid against said plate to be etched, enclosure means for said tank and said fiuid, a saddle member rotatably supported in said tank and in spaced relation above the level of said fluid for holding said plate, a shaft rotatably supported in said saddle, means for mounting said plate in curved configuration on said shaft, first gear means for rotating said saddle about a generally vertical axis, second gear means for rotating said shaft in said saddle about a generally horizontal axis, operating means for said first gear means, operating means for said second gear means, and means interconnecting said operating means for effecting simultaneous rotation of said saddle and shaft at the start of the etching operation, whereby said curved plate is uniformly exposed to said etching fluid.

8. The invention as defined in claim 7, wherein said first operating means includes a motor, a rotatable crank arm, means effecting'a driving connection between said crank arm and said motor, a link member having one end thereto pinned to said crank member, an oscillating lever pinned to the other end of said link member, and means interconnecting the free end of said oscillating lever to said first gear means, whereby rotation of said crank member effects a back and forth movement of said oscillating lever to reverse the direction of said first gear means; and wherein said second operating means includes an electrical motor, a worm driven by said motor and in driving engagement with said second gear, and a timer member for reversing the direction of said electrical motor to reverse the direction of rotation of said worm and associated gear means.

9. The invention as defined in. claim 1 wherein said plate mounting means includes elements for accommodat- 3,122,150 9 ing arcuate plates of various sizes and means for revolving said various-sized plates at a uniform peripheral speed during the etching thereof.

References Cited in the file of this patent UNITED STATES PATENTS The invention as defined in claim 3 m the 993,503 Br ov vnmg May 30, rical mo or for said second operating means indudcs 1, 1 Hilliard Aug. 22, 1 means for adjusting the speed thereof whereby the Pg 1,836,444 e n Dec. 15, 921 p l sp ed of said plates is controlled t eff t 1,850,968 M rt n Mar. 22, 19.. form peripheral speed of plates of Various-sized curved 2,824,029 y F 18, 195 Configurations, 3,078,857 Gu L Feb. 26, 196.7

Claims (1)

1. IN AN ETCHING MACHINE FOR ETCHING PRINTING PLATES, THE COMBINATION OF A TANK FOR HOLDING A SUPPLY OF ETCHING FLUID, MEANS FOR VIGOROUSLY APPLYING SAID FLUID AGAINST SAID PLATE TO BE ETCHED, MEANS FOR ENCLOSING SAID TANK AND FLUID, A PLATE HOLDER REVOLVABLY SUPPORTED IN SAID TANK AND DISPOSED ABOVE THE LEVEL OF SAID FLUID, MEANS FOR ROTATABLY MOUNTING AT LEAST ONE OF SAID PLATES IN SAID PLATE HOLDER, AND MEANS FOR REVOLVING SAID PLATE HOLDER ABOUT A

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