US2910939A - Mechanism for clamping flexible printing plates to the plate cylinder of machines for flat printing - Google Patents

Description

Nov. 3, 1959 M. MOSEGAARD 2,910,939

CLAMPI PLATES MECHANISM FOR NG FLEXIBLE PRINT TO THE PLATE C NDER OF MACHI FOR FL PRINTING Fig.1

Filed June 23, 1958 4 Sheets-Sheet 1 Fig.2

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r ll 22 Nov. 3, 1959 M. M EGAAR 2,910,939

MECHANISM FOR C P1 FLEXIBLE INTING PLATES TO THE P TE CYLINDER MACHINES FOR FLAT PRIN G Filed June 23, 1958 4 Sheets-Sheet 2 73 A 3/2 79 0c B //6 Fig, 6 52 Ty e d 6'4 22 @pefi 7' e B 52 50 54 I 48 fifvENToR.

Nov. 3, 1959 M. MOSEGAARD 2,910,939

MECHANISM FOR CLAMPING FLEXIBLE PRINTING PLATES TO L T Filed June 23, 1958 wgx Mar/w M0J644Aw BY 19M x1 Wm Nov. 3, 1959 M. MOSEGAARD 2,910,939

MECHANISM FOR CLAMPING FLEXIBLE FRI NG PLATES TO THE PLATE CYLINDER OF MAC INES FOR FLAT PRINTING Filed June 23, 1958 Fig.8 42 91 4 Sheets-Sheet. 4

H910 24 4o 2{8 4o 24 34 36 LEE LmuLuHni INVENTOR.

MAE/(A9 Moa amea BY United States Patent MECHANISM FOR CLAMPING FLEXlBLE PRINT- ING PLATES TO THE PLATE CYLINDER OF MACHINES FOR FLAT PRINTING 3 Claims. (Cl. 101-415.1)

Denmark, assignor to Denmark, a Danish This invention relates to a mechanism for clamping flexible printing plates to the plate cylinder of machines, particularly high-speed rotary machines, for flat printing, preferably offset printing, wherein the ends of the printing plate are connected to two rails or lists which are received in an axially extending recess or groove in the circumferential surface of the cylinder.

Such mechanisms have been made in many different ways. It has been suggested to place wedge pieces behind the lists, which wedges cooperate with inclined surfaces in the cylinder recess and press against the rear sides of the lists so as to move same in tangential direction during the tightening of the printing plate. The wedge pieces may e.g. be influenced by means of screws, which are placed radially inthe cylinder recess and force the wedge pieces outwards. Such a mechanism has proved expedient in practice, although the construction becomes rather complicated.

According to the present invention a' more simple construction is obtained by placing transversely of the rails a number of shafts, each of which is mounted in bores in both rails and carries an adjusting disc in the slot between the rails, the ends of the shafts cooperating with the walls limiting the groove or recess so that by turning the shafts the rails can be adjusted indifferent directions within the space confined by the walls of the groove.

This rather universal adjustment can be obtained thereby that some of the shafts are threaded at one or the other side of the adjusting disc, and that said screw threads cooperate with screw threads in the corresponding bore in the rail, while the other end or both ends of the shaft abut against one of the walls or both walls limiting the groove or against abutment pieces positioned here. Said shafts can be used. to adjust the rails in tangential direction to one or the other side. According to the invention an adjustment of the rails in the perpendicular direction, i.e. in a plane through the axis of the cylinder, is obtained by the measure that some others of the shafts are mounted in smooth bores in either rail and at both ends have eccentric journals, which cooperate with axially extending abutment faces in the walls limiting the groove or with slide blocks, which are displaceable in axially extending grooves in said walls.

Other characteristic features of the invention will appear from the following description with reference to the drawings, which depict one embodiment of the mechanism according to the invention.

Figures 1 and 2 show an axial section through a plate cylinder for a rotary machine, taken at the circumference centrally through the groove which receives said mechanism, said section extending through half the length of the cylinder only,

Figures 3 and 4 show on a larger scale part of the mechanism as seen from the outer side of the cylinder,

Figures 5 and 6 are a section of same along a plane perpendicular to an axial plane through the center of the groove, and

ice

Figures 7, 8, 9 and 10 show on a larger scale sections along the lines IV--IV, V-V, VIVI, and VIIVII, respectively, in Figure 2.

In the surface of the plate cylinder 10 an axially extending groove or recess 12 with substantially rec tangular cross section is provided. At the ends of the cylinder this recess is terminated by means of rings 14, which in known manner are attached to the end faces of the cylinder. At the sides of the recess two bars 16 are inserted, which are attached by means of screws 20, see Figure 10, to a bar 18, situated at the bottom of the recess, whereupon the bar 18 is attached to the cylinder 10 by means of screws 22, see Figures 1 and 2. At the top of their sides facing inwards the bars 16 have inclined surfaces 24, so that the three bars 16, 16, and 18 together will form an undercut groove 26, whose aperture at the surface of the cylinder is a narrow slit 28. In this groove two rails 30 and 32 are disposed, which in the outward direction towards the surface of the cylinder are wedge-shaped by means of inclined surfaces 34, Figure 10, extending from their side facing outwards towards their side facing inwards in the same direction as the appertaining inclined surfaces 24. The rails 30 and 32 serve to fasten the ends of a flexible plate 36 which consists of suitable metal, e.g. stainless steel, and which constitutes the printing plate.

For attaching the edges 40 of the plate 36 to the rails 30 and 32 these latter have on their surfaces facing each other narrow axially extending grooves 38 which receive the bent edges 44 of the printing plate which is bent also at the circumference of the plate cylinder and extends inwardly through the slit 28 to the grooves 38.

For the adjustment of the rails 30 and 32 in different direction within the clearance between same and the wall surfaces of the groove 26 a number of adjusting discs 42 are used, which are so thin that they can be received'in the narrow slit between said rails, and which at either side have shafts 44 disposed in continuation of each other. The disc and the shafts are preferably integral.

The said discs are distributed throughout the length of.

the groove 26 in groups of five, as will be seen from Figures 1 and 2.

The shafts 44 are mounted in bores, in both rails 30 and 32, but in different ways so as to serve different purposes, as will appear from the following. Three different type are provided, A, B, and C, shown in Figures 7, 9 and 8, respectively.

As regards type A the left-side shaft 44, Figure 7, has screw threads 46, which cooperate with corresponding screw threads in the rail 30, whereas the right-side shaft is smooth and is received in a corresponding smooth bore in the rail 32. The end faces of the two shafts 44 abut against abutment pieces 43, which are inserted in corresponding recesses in the bars 16. When the adjusting disc 42 is turned, the rail 30 will be displaced to the right or to the left, depending on the direction of rotation, as the shafts 44 cannot be axially displaced, because their end faces rest against the pieces 48.

Type B, shown in Figure 9, is identical with type A, the only difference being that it is the right-side shaft 44 which is provided with screw threads 46 cooperating with screw threads in the rail 32, whereas the other shaft is smooth. This makes it possible to adjust this rail to the right and to the left by turning the disc 42.

As regards type C, both shafts 44 are smooth and mounted in smooth bores in the rails 30 and 32, see Figure 8. At their ends both shafts have eccentric journals 50, which are received in bores in slide blocks 52 being displaceable in short axially extending grooves 54 in the bars 16, see Figures 5 and 6. When the disc 42 is turned, both rails 30 and 32 can be displaced downwardly from the position shown in Figures 1-2 and 8 eccentricity of the journals 50 in relation to the shafts 44. Simultaneously, the blocks 52 reciprocate slightly in the grooves 54.

For each group of adjusting means the various types are placed in the succession shown in Figures 5 and 6 with type A and type B being closely juxtaposed at either end of the group, and type C being found at the center of the group. By using the adjusting means of type A and type B the rails 30 and 32, respectively, and consequently the edges of the printing plate 36 can be adjusted to either side, so that it is possible to obtain an exact registration. Besides, by these adjusting means a tightening of the printing plate can be obtained. The final tightening of this plate is effected with the adjusting means of type C by simultaneous lowering of the rails 30 and 32, whereby it is also ensured that no parts will protrude at the mouth of the slit 28.

As several groups of adjusting means are provided, it will be possible to obtain a very even and uniform clamping and tightening of the printing plate.

In the shown embodiment the adjusting discs 42 are provided at their circumference with notches 56, so that they can be turned by means of a hook spanner, not shown, which is introduced through the slit 2%.

By the engagement of the bent edges 46 of the printing plate 36 with the grooves 38 in the rails 30 and 32, a suflicient securing of the printing plate is obtained, without any need for soldering or spot welding. Therefore, when removing or fixing the printing plate it is not necessary to remove the rails from the groove 26.

It is to be understood that the invention is not to be limited to the embodiment shown in the drawing, as obvious modifications will be apparent to one skilled in the art and the invention is therefore to be limited only by the scope of the appended claims.

Having thus fully described my invention I claim as new and desire to secure by Letters Patent:

1. A plate cylinder for rotary printing machines, comprising a pair of groove defining walls extending axially of said cylinder and substantially parallel to a plane through the axis of said cylinder, printing plate clamping means arranged within said groove, a printing plate mounted on the cylindrical surface of said cylinder and having axially extending edges to be secured by said clamping means within said groove, an adjustment device for adjusting the relative position of said clamping means being provided within said groove between said clamping means, said adjustment device including a plurality of discs rotatable with shafts supported by said clamping means, alternative ends of said shafts being threaded to cooperate with threads in association with one or other of said clamping means, and at least one disc formed with a smooth shaft penetrating through said clamping means and terminating in journals being eccentric in relation to the shaft, bearings for said journals being provided in the walls of the groove extending axial at the surface of the plate cylinder, said bearings being axially slidable.

2. A plate cylinder for rotary printing machines, comprising parallel walls defining an axially extending,

groove, adjustable rails within said groove being spaced to leave a gap therebetween, a flexible printing plate including edges extending into said gap, clamping means provided on said rails facing said gap and arranged to secure said printing plate edges, adjusting devices associated with said rails for radial and peripheral adjustment thereof, said adjusting devices each comprising a disc mounted within said gap with a disc-carrying shaft extending normal to the axial direction and to the radius of said plate cylinder, the ends of said shaft being eccentrically offset in relation to the shaft proper, and bearings for said offset shaft ends provided in the groovedeiining walls so as to allow for a limited movement of the bearings in response to adjustment of the rails.

3. A plate cylinder for rotary printing machines, comprising a pair of groove-defining walls extending axially of said cylinder and substantially parallel to a plane through the axis of said cylinder, printing plate clamping means arranged within said groove, a printing plate mounted on the cylindrical surface of said cylinder and having axially extending edges to be secured by said clamping means within said groove, an adjustment device for adjusting the relative position of said clamping means being provided within said groove between said clamping means, said adjustment device including a plurality of discs rotatable with shafts supported by said clamping means, alternative ends of said shafts being threaded to cooperate with threads in association with one or other of said clamping means, and at least one disc formed with a smooth shaft penetrating through said clamping means and terminating in journals being eccentric in relation to the shaft, bearings for said journals beingv provided in the walls of the groove extending axial at the surface of the plate cylinder.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Sept. 5, 1956 i

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