US2837994A

US2837994A - Lock-up

Info

Publication number: US2837994A
Application number: US658154A
Authority: US
Inventors: Brodie George Rogers
Original assignee: Levey Fred K H Co Inc
Current assignee: Fredk H Levey Co Inc
Priority date: 1957-05-09
Filing date: 1957-05-09
Publication date: 1958-06-10
Anticipated expiration: 1975-06-10

Description

June 10, 1958 G. R. BR ODIE 2,837,994

LOCK-UP Filed May 9, 1957 4 2 Sheets-Sheet 1 FIG! INVENTOR GEORGE R. BRODIE June 10, 1958 G. R. BRODlE 2,837,994

LOCK-UP Filed May 9, 1957 I 2 Sheets-Sheet 2 FIG. 4

w mamzvk United States Patent LOCK-UP George Rogers Brodie, Narberth, Pa., assignor to Fredk H. Levey Company, Inc, New York, N. Y., a eorporation of Delaware Application May 9, 1957, Serial No. 658,154

4 Claims. (Cl. 101-=415.1)

This invention relates to improvements in rotary printing presses and, more particularly, such presses adapted to the. use of printing plates consisting of relatively thin metal, plastic or fiber sheets which are wrapped around the periphery of the plate cylinder and each end of the plate firmly held in position thereon by a clamping device, known as a plate lock-up.

The invention provides improved lock-up means for adjusting and clamping the plate in position on the plate cylinder.

Also, in multi-color printing, for instance, it is essential that each plate be preciselypositioned on the plate cylinder in order to obtain exact register of each plate on the web. Frequently, it is found that the image is not quite accurately positioned on the plate, and it has become necessary to twist or cant the plate slightly with respect to the plate cylinder in order to bring the printed image into precise register with that of the other plates.

It has previously been proposed to secure the plate to the plate cylinder by means of clamping bars or jaws extending longitudinally. of the cylinder and extending outwardly through a longitudinal slot in the peripheral surface of a cylinder to a point substantially flush with the surface thereof. Various means have been proposed for securing the respective ends of the plate to the jaws, for actuating the jaws and for canting the plate where desired. One such plate lock-up is described and claimed in my Patent 2,745,344.

It is an object of my present invention to provide a simplified lock-up of more economical design, especially adapted for use on smaller moderate-sized presses and whereby the plates may be more readily secured in position on the cylinder adjusted with respect thereto and detached therefrom, and whereby extensive preparation of the ends of the plate'rnay be avoided.

These and other objects are accomplished by my improved lock-up, as will hereafter appear from the following description thereof with reference to the accompanying drawings, which represent my presently preferred embodiment of the invention and of which- Fig. 1 is a longitudinal view of a plate y inder equipped with my improved lock-up,

Fig. 2 is a transverse view of Fig. 1 along the line .2-2, showing more particularly means for rotating the :shafts for tightening the plate,

Fig. 3 is a transverse view along the line 3-3 of Fig. 1 showing more particularly means whereby the plate may be canted with respect to the cylinder, and

Fig. 4 is a fragmentary sectional view along the line 4-4 of Fig. 1.

Referring more particularly to Fig. l of the drawings, the plate cylinder, represented at 1, is provided at each end with bearer rings 2 and is supported at each end by means of journals 3 which, in turn, are rotatably supported by press side frames fragmentarily represented at '4. A gear 5 secured to one end of the journal 3 is adapted to cooperate with the press driving mechanism for rotating the plate cylinder.

2,837,994 Patented June 10, 1958 "ice In operation, a printing plate indicated at 6, of exaggerated thickness for clarity, is Wrapped about the periphery of the plate cylinder with its respective ends extending inwardly through longitudinal slot 7 in the pethe cylinder by means of machine bolts 10, so as to present a cylindrical peripheral surface unbroken except for the longitudinal slot 7.

A pair of parallel shafts 11 extend longitudinally through the chamber 9, one positioned to each side of the slot 7 and each being rotatably supported at their ends by means of journals 12. One end of these parallel shafts is supported by an adjustable journal block 13 adapted to be moved transversely of the cylinder axis by means of adjustment bolts 14 and to be held in the adjusted position by means of machine screws 15 extending through enlarged bolt holes in the journal block into the corresponding end of the cylinder.

Secured to the other ends of the journals 12 are a pair of lever arms 16. The inner end of these arms are adapted to fit over the ends of journals 12 and are secured thereto by pressure exerted by machine screws 17, the collar about the shafts being split as indicated at 18.

The outer ends of the respectivearms are equipped with a rotatable lug 19 threaded to receive one end of turn bolt 20. The other end of the respective turn boltsis threaded into lug 21 rotatably secured to plate 22 which, in turn, is secured to the end of the cylinder by machine screws indicated at 23.

Advantageously, the respective ends of the turn bolts 20 are differentially threaded, for instance, l-8 and l'l4,-so that rotation of the bolt by means of a wrench, or the like, adapted to fit on the bolthead at 24, causes the swinging of the lever arm and rotation of the respective journals 12. It will be understood, however,

As shown more particularly in Fig. 4 of the draw- I ings, a slot 25 is cut substantiallylongitudinally into,

each of the parallel shafts 11 to receive the inner ends of a pair of clamping plates 26. These slots 25 are slightly wider than the combined thickness of the two plates so that the plates of each pair, while in position in the slot, may be moved apart sufficiently to receive between them one end of the printing plate. These slots 25 should be substantially rectangular in cross section and advan tageously are cut at an angle with the radius of the shaft, as shown in Fig. 4 of the drawings, so as to exert greater clamping action between the plates when force is exerted on the outer ends of the plates.

That plate of each pair furtherest removed from the other pair extends outwardly through the slot 7 and terminates, advantageously in a tapered edge, substan tially flush with the periphery of the cylinder. The second plate of the pair may be of substantially the same width, but generally I prefer to use an inner plate of somewhat less width than the outer plate.

These clamping plates should be sufficiently rigid to exert the necessary clamping action on the ends of the printing plate when the respective shafts 11 are turned in a direction adapted to exert tension on the printing plate. I have found it especially advantageous, however,

to use as the outer plate of each pair one having a semi rigid outer end so that minor irregularities in the bending of the ends of the printing plate, at the points where they enter groove 7, may be accommodated by a corresponding flexing of the end of the plate, thus avoiding the exertion of undue stress which might result in distorting or tearing the plate.

In preparing the printing plate for securing to the plate cylinder, all that is necessary is the bending of the respective ends of the plate so that they may be inserted through the gap '7 in between the clamping plates of the respective pairs. Advantageously the bent end of the plate should be of sufficient length to reach to the bottom of the plate retaining groove.

By this arrangement the plates are readily secured to the plate cylinder by wrapping the plate about the cylinder and inserting its bent ends between the respective clamping plates. This is readily accomplished when both pairs of plates are in the unlocked position. By rotating the shafts, one toward the other, by appropriate movement of turn bolt 20, the plate exerts tension on the outer ends of the pair of clamping plates, thus tightly clamping the bent end of the printing plate between the pair of clamping plates, and further turning of the shafts in the ap propriate directions tightens the printing plate on the cylinder.

Where it is desired to cause a canting of the plate, the printing plate is loosened slightly, by appropriate turning of the shafts, and the canting effected by adjustment of the position of the movable journal block.

It will be apparent, in view of the foregoing disclosure, that various modifications are possible without departing from the scope and spirit of my invention.

I claim:

1. A lock-up adapted to the clamping of the printing plate on the plate cylinder of a rotary printing press, comprising two parallel shafts rotatably mounted at their ends, extending longitudinally through the plate cylinder and positioned beneath, and one on each side of, a longitudinal slot in the peripheral surface of the cylinder, the ends of at least one of the pair of shafts being mounted in a journal block adapted to be moved transversely of the longitudinal axis of the cylinder, means for so moving said journal block and for holding the journal block in the adjusted position, means for rotating said shafts'about their respective axes, two pairs of parallel clamping plates coextensive in length with the width of the printing plate, a longitudinal slot of substantially rectangular cross section in each shaft adapted to receive one edge of a pair of the parallel plates, the

plate of each pair furtherest removed from the other pair extending outwardly through the longitudinal slot and terminating substantially flush with the periphery of the cylinder, the width of the slots in the respective shafts being slightly greater than the combined thicknesses of the pair of plates, so that the plates of each pair, while in position within the slot, may be moved apart sufiiciently to receive between them one end of the printing plate, when no stress isexerted on the outer edge of the plates, and will be forced together when stress is exerted on the outer edge of the plates to clamp the end of the printing plate inserted between them.

2. In conjunction with a plate cylinder of a rotary printing press, a lock-up adapted to the clamping of the printing plate to the plate cylinder comprising a pair of parallel face-plates adapted to fit flush with the peripheral surface of the cylinder coextensive with the width of the printing plate and spaced apart to provide a longitudinal gap for the insertion of the respective ends of the plate to be clamped, the adjacent edges of the face-plates being under-cut to provide a longitudinal chamber within the cylinder, two parallel shafts extending longitudinally through said chamber and positioned beneath, and one to each side of, said longitudinal gap, the shafts being rotatably mounted at their ends, the ends of at least one of the pair of shafts being mounted in a journal block adapted to be moved transversely of the longitudinal axis of the cylinder, means for so moving said journal block and for holding the block in the adjusted position, means for rotating said shafts about their respective axes, two pairs of parallel clamping plates coextensive in length with the width of the printing plate, a longitudinal slot of substantially rectangular cross section in each shaft adapted to receive one edge of a pair of the parallel plates, the plate of each pair furtherest removed from the other pair extending outwardly through the longitudinal slot and terminating substantially flush with the periphery of the cylinder, the width of the slot in the respective shafts being slightly greater than the combined thicknesses of the pair of plates, so that the plates of each pair, while in position in the slot, may be moved apart sufficiently to receive between them one end of the printing plate, when no stress is exerted on the outer edge of the plates, and will be forced together when stress is exerted on the outer edge of the plates to clamp the ends of the printing plate inserted between them.

3. The lock-up of claim 1 in which that clamping plate of each pair furtherest removed from the other pair of clamping plates is of semi-rigid construction.

4. The lock-up of claim 1 in which that plate of the pair of clamping plates furtherest removed from the other pair is tapered at its outer edge.

No references cited.