US3677121A

US3677121A - Printing plates in registry

Info

Publication number: US3677121A
Application number: US80288A
Authority: US
Inventors: Gordon Etchell
Original assignee: North American Rockwell Corp
Current assignee: Boeing North American Inc
Priority date: 1970-10-13
Filing date: 1970-10-13
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18

Abstract

A machine for trimming flexible letter press printing plates to final size and simultaneously punching mounting appertures therein in accurate register with the plate image. The illustrated machine includes a vertically moveable die head and a die base plate with structure for supporting an untrimmed flexible printing plate in a predetermined position on the base plate. The die base plate is laterally moveable from an outwardly extended position to a determined position directly below the die head. When the die base plate is in proper position beneath the die head, selectively operable hydraulic actuating elements may lower the die head, into contact with the die base plate to trim and punch the flexible plate in finished form.

Description

United States Patent Etchell 1 July 18, 1972 54] PRINTING PLATES IN REGISTRY 3,509,789 5/1970 Dye ..83/62() x 1121 Gordon Downers m 5:323:32? 131132? 8553311133...........11:13::331113111331253 [73] Assignee: North ,American Rockwell Corporation,

Pi b h p Primary Examiner-Donald G. Kelly Att0rneyDaniel H, Dunbar, Floyd S. Levison, E. Dennis O- [22] led: 1970 Connor, Richard A. Speer and John R. Bronaugh 0.: 21 Appl N 80,288 [57] ABSTRACT 52 US. Cl ..s3/437, 83/524, 83/563, A machine for trimming flexible Press Priming Plates 33/620 final size and simultaneously punching mounting appertures 51 1111, c1. ..B26d 7/06, B26d 7/16 herein in accurate resist" the image The [58] Field of Search ..s3/400, 437, 524, 563, 620, machine a vmicaly mmeable die head and 8 83/622 682 637 die base plate with structure for supporting an untrimmed flexible printing plate in a predetermined position on the base [56] References Cited plate. The die base plate is laterally moveable from an outwardly extended position to a determined position directly UNITED STATES PATENTS below the die head. When the die base plate is in proper position beneath the die head, selectively operable hydraulic ac- 2,171,785 9/1939 Drucker ..83/682 X mating elements may lower the i head i Contact i the 31368144] 2/1968 Pazze "83/682 die base plate to trim and punch the flexible plate in finished 3,368,479 2/1968 Gregorovich.. .....83/563 form 1,194,268 8/1916 Bauchwitz ..83/563 3,198,051 8/1965 Ablon ..83/620 X 10 Claims, 10 Drawing Figures PATENTEU JUL 1 81972 SHEET 1 BF 3 EEK PRINTING PLATES IN REGISTRY DESCRIPTION OF THE INVENTION The present invention relates generally to flexible printing plates and more particularly to a machine for trimming and punching such plates for mounting on an appropriate saddle or plate roll of a printing press.

In preparing flexible printing plates for use in letter press printing, the desired image from an appropriate negative is etched into a sheet of flexible material, such as Mylar, by known means. The excessive edge portions of the sheet must then be trimmed and holes generally must be punched into the opposite ends of the plate in exact relation to the image so that when the plate is secured on the press roll the image is in accurate register. The accuracy of the plate register is particularly important in color printing since several different plates may be required for a single printed character. Heretofore, to insure accurate trimming and punching of the plates, it has been the practice to place each plate over a light box, align the image with reference points, and then trim and punch the plate by hand. This procedure, however, has been time-consuming, cumbersome, and frequently inaccurate.

Accordingly, it is an object of the present invention to provide a machine adapted to trim and punch flexible printing plates neatly, efficiently, and in accurate register.

It is a related object to provide a machine of the above kind which simultaneously punches and trims a flexible printing plate in accurate register with the image.

Another object is to provide a machine as characterized above which is simple in operation and facilitates easy handling of the plates during placement into and removal from the machine.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIG. 1 is a perspective of a plate trimming and punching machine embodying the present invention;

FIG. 2 is a partially diagrammatic perspective of an untrimmed sheet having an image etched therein;

FIG. 3 is a side elevation view of the machine shown in FIG.

FIG. 4 is a front elevation view of the machine shown in FIG. 1;

FIG. 5 is a top view of the machine shown in FIG. 1;

FIG. 6 is an enlarged fragmentary section taken in the plane ofline 6-6 of FIG. 5;

FIG. 7 is a vertical section taken in the plane of line 7-7 in FIG. 5;

FIG. 8 is an enlarged fragmentary section taken in the plane of line 8-8 in FIG. 7;

FIG. 9 is a partially diagrammatic perspective of a printing plate after it has been punched and trimmed by the machine of the present invention with the excess portions shown in phantom;

FIG. 10 is a fragmentary view of the underside of the die head taken in the plane of line 10-10 in FIG. 4.

While the invention is susceptible to various modifications and alternate constructions, an illustrative embodiment thereof has been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention.

Referring more particularly to the drawings, there is shown an illustrative machine 10 embodying the present invention. The machine 10 is adapted to neatly and efficiently trim and punch a flexible plate 11 bearing a desired image 12, such as shown in FIG. 2, so that the finished plate may be mounted in proper operating condition on a press.

In preparing the flexible plate 11, an image from an appropriate negative may be etched or otherwise imparted into the sheet by processes which are well known in the art. As a result of the etching process, the surfaces of the image 12 on the plate which are to be printed are raised slightly, on the order of 0.02 inches, above the remaining surfaces of the plate. During the etching process, register marks 14 located in predetermined relation to the image 12 also are formed in the sheet 11, being in this case in the form of raised dots. As is known to one skilled in the art, register marks may be made in the original copy prior to photographing, or the camera may automatically punch register holes into the film or otherwise mark the film when the copy is photographed. In either case, the register marks carry over onto the negative and the untrimmed plate 11 in predetermined relation to the image. After the flexible plate 11 shown in FIG. 2 has been prepared, the excess edge portions must then be trimmed and holes generally must be punched in opposite ends of the sheet to facilitate mounting of the plate on a press.

In accordance with the present invention, the machine 10 is adapted to simultaneously trim and punch a flexible plate sheet 11 so that the resulting plate may be readily mounted on a saddle or press with the image in accurate register. The illustrated machine comprises a rectangular shaped cabinet 15 supporting a vertically movable punching and trimming die head 16 and a die base carriage 18 that is laterally movable from an outer extended position to a position directly under the die head 16. The cabinet includes side panels 20, front and back panels, 21, and 22, and a bottom panel 24. A relatively massive bottom die holder 25 is mounted directly on the top of the cabinet 15 and serves as a base for the die base carriage 18.

To support the die base carriage 18 in its outer extended position, a frame support 26 is secured in cantilever fashion by brackets 28 to the bottom die holder 25 and extends horizontally out from the front of the cabinet. For added support, diagonal members 29 are secured between the outermost end of the support frame 26 and the front cabinet panel 21.

The die base carriage 18 includes a die base plate 30 with pairs of rollers 31 disposed at opposite ends thereof to permit easy manual rolling movement of the carriage from its outer position on the support frame 26 to the position under the die head 16. When the die base carriage 18 is in its outer position, the untrimmed plate 11 may be positioned on the upper surface of the die base plate 30 with the image facing down. The die base plate 30 is formed with a rectangular recessed area 32 corresponding substantially to the size of the plate image 12 and has a depth approximately the same as the elevation of the image. To accurately orient the image 12 with respect to the die base plate 30, the die base plate is also formed with register holes 34 into which the register dots or marks 14 of the flexible plate may be inserted.

To facilitate manual lateral movement of the die base carriage 18 handles 35 are provided at the front side of the die base plate 30. The rollers 31 are slightly larger than the thickness of the die base plate 30 so that during the rolling movement the plate is elevated out of frictional contact with the bottom die holder 25 and support frame 26. Each roller 31 preferably is formed with an outermost layer of neoprene material so that when the plate is struck by the die head 16, as will be discussed below, the neoprene deforms slightly to cause the die plate 30 to rest firmly on the bottom die holder 25. In order that the die base plate 30 may be guided to a precisely determined position beneath the die head 16, guide rails 36 are mounted on top of the bottom die holder 25 and frame support 26 and cooperate with the underside of the die base carriage 18. Suitable adjustable stops 38 are also provided at the rear of the machine for limiting the inward carriage travel at the desired position.

In keeping with the invention, the underside of the die base head is provided with downwardly directed die knives and punches appropriately oriented so that when the die base plate carrying an untrimmed flexible plate is positioned under the die head and the latter is lowered into contact with the die base plate, the plate is trimmed to the desired finish size and appertures are punched along opposite edges of the plate.

Referring to FIG. 10, the underside of the die head 16 is provided with depending die knives 40 arranged in rectangular configuration for trimming the edge portions of the flexible plate 11 (FIG. 2) to finished size 42 (FIG. 9) and spaced punches 41 are provided for simultaneously forming a series of appertures 44 (FIG. 9) in the flexible plate. It will be appreciated that the arrangement of the knives 40 and punches 41 may be designed for the particular size of plate 42 desired and the type of plate locking mechanism that is to be used to mount the printing plate on a saddle or press. It is important, however, that the die head 16 and die base plate 30 be designed and positioned with respect to each other so that the flexible plate is trimmed and punched in precise register with the image 12 when the die head is lowered into contact with the die base plate.

Vertical movement of the die head 16 is guided by guide rods 45 mounted in depending fashion from the comer portions of the die head 16 with the lower ends thereof slidably disposed in the bottom die holder 25, as shown in FIG. 8. The rods 45 in this case are press fitted into apertures in the die head 16, and sleeves 46 are press fitted into apertures in the bottom die holder 25 and extend a predetermined distance above the upper surface thereof. To facilitate sliding movement of each rod 45 relative to the sleeve 46, a ball cage 48 is interposed between the two and is free to experience a limited range of movement as the die head 16 is moved.

In order to raise and lower the die head 16, hydraulic cylinders 50 are provided near the opposite ends of the die head. As best illustrated in FIG. 6, each hydraulic cylinder 50 is secured to the underside of the bottom die holder 25 and includes a piston 51 with a piston rod 52 extending upwardly therefrom and being secured at its upper end to the die head 16. The upper piston end in this case is fonned with a reduced diameter portion defining a shoulder 54 and a bolt 55 is threaded onto the end of the rod 52 securing the die head against the shoulder 54. A fluid supply line 56 and port 58 are provided for supplying pressurized fluid to the chamber below the piston 51, as shown in FIG. 6, and a supply line 59 and port 60 also are provided on the opposite side of the piston. An appropriate motor 61, a pump 62 connected to the motor by a coupling 64, and a fluid reservoir tank 65 associated with the pump are provided in a lower portion of the machine cabinet for actuating the hydraulic cylinders 50. It will be apparent to one skilled in the art that the supply lines 56 and 59 may be connected to the pump 62 by suitable means so that pressurized fluid may be selectively supplied to the lines.

It can be seen that when pressure fluid is supplied to the line 59 and port 60 on the upper side of the piston 50, as shown in FIG. 6, the piston will be forced in a downward direction pulling the die head 16 downwardly. A sleeve 66 surrounding each piston rod 52 functions as a die head stop to limit downward movement of the die head at the point where the knives 40 and punches 41 strike the die base plate 30. This permits the knives 40 and punches 41 to neatly and cleanly cut and punch a flexible plate 11 disposed on the die base plate while preventing damage to the knives and punches from striking the die base plate with excessive force. After the downward stroke of the die head 16, the die head may be raised by supplying pressure fluid to the port 58 which will force the piston 51 in an upward direction. A stop 68 surrounding the rod 52 within the cylinder serves to limit upward movement of the piston and also preserve the fluid chamber above the piston at all times.

Actuation of the hydraulic cylinders for lowering the die head is effected in the illustrated embodiment by depressing buttons 70 located on opposite sides of the support frame 26. Wiring may be passed from the buttons 70 through the frame support 26 to suitable control circuitry within the cabinet 15. It will be understood that actuation of hydraulic cylinders 50 for lowering the die head should be appropriately controlled to insure that the die base plate 30 is in proper position beneath the die head. In the illustrated machine, a limit switch 71 is located at the rear of the bottom die holder 25 and is contacted by the carriage 18 when it reaches its stopped position. Until the limit switch 71 is contacted, the control circuitry for the machine prevents actuation of the cylinders 50 and lowering of die head 16. After the die head has completed its downward stroke, the buttons may be released to actuate the cylinders by imparting pressure to the lines 56 to lift the die head to its raised position. A limit switch 72 is provided to automatically de-energize the motor 16 when the die head reaches the raised position.

Thus, in operation, when the die head 16 is in its elevated position and the die base plate is in its extended position shown in FIG. 1 an untrimmed plate 11 may be placed with the image 12 face down on the die base plate 30 and the plate register marks 14 set in the register holes 34. This orients the flexible plate in proper position on the die base plate. By means of the handles 35, the die base carriage may then be rolled to a position under the die head until it strikes the stop 38 and contacts the limit switch 71. At that point, the die base plate 30 and the flexible plate it supports are properly oriented with respect to the die head 16. The hydraulic cylinders 50 may then be activated by pressing the buttons 70 to lower the die head 16 so that the knives 40 and punches 41 simultaneously trim the edge portions of the plate to the finish size 42 and punch apertures 44 in the opposite ends of the plate in accurate register to the image 12. As the die head 16 strikes the base plate 30, the resilient rollers 31 deform slightly so that the die base plate 30 is firmly supported by the bottom die holder 25. After completion of the downward stroke of the die head, the buttons 70 may be released to actuate the cylinders for return of the die head to its raised starting position. When the die head reaches its raised position and contacts the limit switch 72, the motor of the machine is automatically shut off. The die base carriage 18 may then be pulled out onto the support frame 26 and the finished plate 42 may be readily removed from it and replaced by another plate to be trimmed.

In view of the foregoing, it can be seen that the machine of the present invention is adapted to simultaneously punch and trim flexible printing plates neatly, efficiently, and in accurate register with the plate image. Moreover, the machine is simple in operation and facilitates easy handling of the plates during the trimming and punching operations.

I claim as my invention:

1. A machine for trimming and punching a flexible printing plate having an image formed therein comprising a base,

a die base plate mounted on said base for supporting a flexible printing plate,

register means on the upper surface and within the perimeter of said die base plate for locating said flexible printing plate and the image formed therein in predetermined position relative to said die base plate,

a die head mounted on said base in parallel relation to said die base plate, said die head and die base plate being relatively movable in a direction perpendicular to their planes,

said die head having knife and punch means directed toward said die base plate, and means for selectively effecting relative movement of said die head and die base plate toward each other so that said knife and punch means simultaneously trim a flexible printing plate supported on said die base plate to a desired finished size and punch holes therein in predetermined relation to said image.

2. The machine of claim 1 in which said die head is disposed in a position above said die base plate, and said die base plate is laterally moveable from a position directly under said die head to an outwardly extended position which permits a flexible plate to be readily placed onto and removed from said die base plate.

3. The machine of claim 2 in which said die head is vertically moveable from a raised position in which said knife and punch means are out of contact with said die base plate to a lowered position in which said knife and punch means contact said die base plate.

said die head, and control means for preventing lowering of 5 said die head from its raised position until said sensing means indicates said die base plate is in said predetermined position.

5. The machine of claim 3 including a support frame extending laterally outward from said base for supporting said die base plate when in its laterally extended position, said die base plate having roller means to facilitate lateral movement over said base and support frame.

6. The machine of claim 5 in which said roller means support said die base plate in a slightly elevated position above said base and support frame during lateral movement of said die base plate, and said roller means includes a resilient layer which compresses under the force of said die head contacting said die base plate so that said die base plate is lowered into firm engagement with said die base during trimming and punching of said flexible plate.

7. The machine of claim 3, including at least one hydraulic cylinder for raising and lowering said die head, said cylinder being mounted on said base and having a piston with a vertically extending piston rod, said die head being secured to said piston rod, and pump means for selectively supplying pressurized fluid to said cylinder to raise and lower said piston, piston rod, and die head.

8. The machine of claim 7 including stop means for limiting downward and upward movement of said die head at predetermined positions, and stop means for limiting lateral movement of said die base plate at a predetermined position below said die head.

9. The machine of claim 8 including sensing means for indicating when said die base plate is in said predetermined position below said die head, control means for preventing said die head to be lowered from its raised position until said die base plate sensing means indicates said die base plate is in said predetermined position, and sensing means for indicating when said die head has been moved to said determined raised position, and control means for automatically stopping said machine when said die head sensing means indicates said die head has been raised to said upper position.

10. The machine of claim 1 wherein the register means includes a plurality of recesses formed in the upper surface of the die base plate.

Claims

1. A machine for trimming and punching a flexible printing plate having an image formed therein comprising a base, a die base plate mounted on said base for supporting a flexible printing plate, register means on the upper surface and within the perimeter of said die base plate for locating said flexible printing plate and the image formed therein in predetermined position relative to said die base plate, a die head mounted on said base in parallel relation to said die base plate, said die head and die base plate being relatively movable in a direction perpendicular to their planes, said die head having knife and punch means directed toward said die base plate, and means for selectively effecting relative movement of said die head and die base plate toward each other so that said knife and punch means simultaneously trim a flexible printing plate supported on said die base plate to a desired finished size and punch holes therein in predetermined relation to said image.

4. The machine of claim 3 including means for stopping lateral movement of said die base plate in predetermined position below said die head, sensing means for indicating when said die base plate is in said predetermined position beneath said die head, and control means for preventing lowering of said die head from its raised position until said sensing means indicates said die base plate is in said predetermined position.