US3001472A - Circumferentially grooved printing plate cylinder - Google Patents

Description

Sept. 26, 1961 J R. PARRIQSH 3,001,472

CIRCUMFERENTIALLY GROOVED PRINTING PLATE CYLINDER Filed July 22, 1957 /Nl ENTOR" 2a 28 az Br 2 W 94% ATTORNEYS.

3 utilize one side of the central groove as the center line.

In looking the plate to the cylinder, the hooks 20 in adjacent circumferential rows are staggered, as best shown in FIGURE 2. The hooks 16a in the top plate run in the inner grooves of the group of five adjacent the left end of the roll. The hooks 16b run in the outer grooves of the same group. The hooks 16c run in the center groove. By staggering the hooks in circumferentially adjacent plates, the hooks may lie side by side in adjacent grooves rather than end to end in the same groove. Consequently,.the circumferential distance between adjacent plates is muchcloser than it would be where access has to be. provided for two hooks rather than one. The circumferential distance between plates is limited by the space required to manipulate the hooks and to adjust the plates for fine color register. This distance is of the order of /1 inch. It will be apparent that with the five groove sets, two, four or five hooks may be used for each plate. The quarter inch spacing between plates circumferentially is required as in all high speed presses for the use of packing slots on the impression cylinder and the impaling pins which handle the folded pages in the press. The perforations left by the pins are usually trimmed off in the bindery.

Because the hooks are connected to the plates at the axial edges thereof, the circumferential edges may be abutted. This permits locating a series of bleed pages contiguously. In compression lockup only two plates can be axially contiguous because of the intervention of hooks engaging the edges of the plates. Any suitable hook adapted to move lengthwise in the circumferential grooves and lock the plate in tension may be" used in this invention. known in the art. The construction of the hook forms no part of the invention. To illustrate one such suitable construction, reference is made to FIGURES 3 and 4. The hook 20 illustrated therein consists of a carriage, indicated generally by the numeral 24, and the integral hook member 22 which slants rearwardly of the hook 20 to fit accurately within the scarfs 16 of the plates 14. The hook is locked in the undercut groove 12. by means of locking bolts 26 which have a T-head 28. By turning the bolt 26 through an angle of 90, the head engages the underside of a pair of opposed racks 40 which project into the groove from the walls thereof, as best shown in FIGURE 5. One such bolt is located at either end of the carriage and permits the carriage to move along the groove in either direction while preventing it from moving radially outwardly. Disposed within the center of the carriage 24 is a worm gear 30 which meshes with the opposed racks 40 in the sides of the groove. The end of the worm gear 3% terminates in a bevel gear 32 which in turn meshes with another bevel gear 34 at right angles thereto. Bevel gear 34, which operates like a pinion, has a slot 36 of hexagonal or other configuration extending therethrough for receiving a wrench, which turns the pinion 34 to rotate the worm 30. Opening 38 in the carriage provides access to slot 36. In this way the carriage and the hook 22 integral therewith are driven (i.e. advanced or retracted) within the circumferential groove 12.

The curvature of plates 14 should be accurately formed to the radius of the cylinder or of smaller radius, but never of greater radius. I have found that if the radius of the plate is greater than that of the cylinder, the plate will move when the press is in operation, although it has been tightened down into contact with the cylinder-face. In assembling, the plate is placed on the cylinder with the scarfs 16 aligned with the appropriate circumferential groove 12. This alignment occurs automatically when the center line of the plate is aligned with the edge of the central groove. The hooks for circumferentially adjacent plates lie side by side in adjacent grooves, as explained above. Consequently, the distance 42 between the plates is maintained at an absolute minimum; By

Various constructions are 4 I using a hexagonal wrench (not shown) the hooks are moved outwardly until the hook members 22 securely engage the scarfs 16, and the plate is held under tension. The axial edges of the plates are aligned with the axial guide lines scribed on the surface of the roll to obtain correct registration.

The plates shown in FIGURE 1 illustrate a difierent circumferential arrangement while maintaining the .COI]: tiguous axial relationship. The staggered plates eliminate an axial space running along the entire length of the cylinder and its attendant difiiculties with respect to registration.

It will be apparent from the. foregoing descriptionthat this particular system of circumferential grooves disposed normal to the axis of the cylinder coupled with a tension 7 lockup permits the plates to use scarfs of minimum length, thus greatly increasing their strength and resistance to fracture during use. I have found that this cylinder-plate assembly construction will withstand very high speeds in the neighborhood of 1200 feet per minute for periods of one month without becoming dislocated or warped. It will also be apparent that the normal circumferential grooves are much easier to cut than the spiral grooves and, thus, the cost of manufacturing a cylinder of this type is substantially less than that for the conventionalcylin der using spiral grooves. It willalso be appreciated that plates may be cut and rescarfed if necessary to obtain more perfect registration. An important advantage of utilizing independently op; erated hooks is that they permit twisting a plate that'is out of square as,- for example, where diagonally opposed corners are out of alignment. It will be understood that the grooves and cooperating scarfs can be diiferently arranged to accommodate other size plates while still maintaining the complementary rel-r ationship explained above. Other changes in the cons struction of the plates and cylinder will be apparent to thoes skilled in the art without departing from the inven tion as defined in the appended claims.

What I claim as new and desire to secure by 'Letters Patent of the United States is: j

1. A printing roll assembly capable of carrying a variable number of printing plates comprising in combination a cylinder having printing plates secured thereto, a plus rality of circumferential grooves cut in the surface of said cylinder, said grooves lying in parallel planes perpendic: ular to the axis of said cylinder, each of said plates hav ing at least three scarfs, one adjacent one edge and two. adjacent the other edge, each said scarf being parallel with'the axis of the cylinder and overlying one of said grooves, securing means comprising hooks disposed with, in said scarfs and a carriage adapted to mom each said groove completely around the circumference of the cylinder independently of carriages in other grooves, and including gear means for driving the carriage within said groove and means carried by the carriage and operable in any position of the carriage within said groove for actuating said gear means, each of said hooks being detachably connected to one said carriage, whereby said hooks are adjustable to exert tension forces on said plates when mounted at any place on the circumference to hold them securely to the surface of the cylinder during high speed rotation. 2. The printing roll assembly of claim 1 wherein said circumferential groove carries racks in opposed sides thereofand said gear means comprises a rotatable worm cooperating with said racks for driving said carriage in said groove. 3. The printing roll assembly of claim 1 wherein each of said scarfs is no longer than three times the width of the groove over which it lies. 4. The printing roll assembly of claim 1 wherein at least one of said plates has four scarfs adjacent opposed edges thereof. v5. The printing roll assembly of claim 1 in which said plates are mounted on the cylinder contiguous'ly in axial TOWS.

References Cited in the file of this patent UNITED STATES PATENTS 6 Schmutz -26.- Feb. 6, 1940 Crafts et a1 Sepm 30, 1947 Crafts July 5, 1949 Faeber Dec. 16, 1952 McWhorter Feb. 9, 1954 McWhorter May 31, 1955 Polglaze et a1. Oct. 27, 1959

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