GB1589488A

GB1589488A - Printing machine cylinder and bearer ring

Info

Publication number: GB1589488A
Application number: GB1742/78A
Authority: GB
Original assignee: MAN Maschinenfabrik Augsburg Nuernberg AG
Current assignee: MAN AG
Priority date: 1977-01-17
Filing date: 1978-01-17
Publication date: 1981-05-13
Also published as: CH615387A5; SE7800469L; DE2701637C2; DE2701637A1; SE438985B

Abstract

To avoid irregularities in the construction of a bearing ring, due to which reflections occur which lead to damage to the bearing ring on the occurrence of impact loads, uneven places are avoided in the bearing ring according to the invention. A bearing ring (25) is mounted with its conical central bore (27) on a conical part (29) of the drive shaft (11) of the printing unit cylinder (3). At several places on its circumference, the part (29) of the shaft bears oil grooves (31) which are connected via bores (33) to a source of compressed oil. The bearing ring (25) is connected to the part (29) of the shaft by a retaining washer (35) and by a screw (37). By means of the source of compressed oil, the bearing ring (25) can be mounted on the part (29) of the shaft and removed again if required. <IMAGE>

Description

(54) PRINTING MACHINE CYLINDER AND BEARER RING 71) We, MASCHINENFABRIK AUGSBURG NURNBERG AKTIENGESELLSCHAFT, a German company, of Stadtbachstrasse 1, 8900 Augsburg, Germany (Fed. Rep.), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a cylinder for a rotary printing machine carried coaxially by a driving shaft, and a bearer ring therefor, the bearer ring being intended, in use, to make rolling contact with another bearer ring associated with another cylinder to determine the distance between the axes of the cylinders. Such bearer rings are sometimes referred to as Schmitz rings. In rotary printing machines having cylinders with Schmitz bearer rings, there is constant contact between the bearer rings of the two associated cylinders, the rings rolling on one another under prestressing.

Schmitz or bearer rings of this kind are in widespread use in rotary printing presses.

They are mostly used for guaranteeing an exact rolling of the individual plate, blanket and impression cylinders, in order to avoid the so-called Schmitz i.e. a defective shadow edge round lettering and images, which occurs when the cylinders do not quite make perfect contact.

The known bearer rings are usually screwed to the front ends of the printing machine cylinders. For this purpose, they are each provided with a central, axially-aligned bore to be located over the driving shaft of the printing machine cylinder and with a number of axially-extending bores in its annular body region for the attachment screws. Furthermore, in this annular region they have several larger bores via which setting and clamping devices at the circumference of the cylinders are accessible.

These Schmitz or bearer rings are occasionally subjected to exceptional shock loads which are attributed to the bearer rings being temporarily lifted from each other and then being banged together with considerable force, as a result of imprecise machine setting in the region of the clamping channels in the plate and blanket cylinders or of large accumulation of ink and paper dust. These shock loads introduce the danger of overloading the bearer rings, which can lead to very costly damage to them.

In the periodical "Printing Machinery News", volume 63 (1976), these conditions are described in detail on pages 3 to 24.

Different possibilities have been proposed for extensively impeding the occurrence of these shock loads, and furthermore, electrical and optical measuring devices have been proposed (for example, in British Patent Specification No 1,548,596) which give due warning of the bearer rings lifting, which lifting leads to the subsequent banging together of the rings and thus to the shock loads mentioned.

According to the present invention there is provided a cylinder for a rotary printing machine carried coaxially by a driving shaft, and a bearer ring therefor, the bearer ring being intended, in use, to make rolling contact with another bearer ring associated with another cylinder to determine the distance between the axes of the cylinders, the bearer ring having a central, axially-extending through bore by which the ring is mounted co-axially on the driving shaft of the cylinder for rotation therewith, at a position spaced axially from the adjacent end of the cylinder, the bearer ring otherwise having no axiallyextending bores therein.

A bearer ring in accordance with the invention may be solidly constructed-except for its central bore and if necessary a number of attachment openings in its central region and is free from bores in its outer region and is attached to the driving shaft of the cylinder at a distance from a front surface of this cylinder.

The underlying theory is that even a perfectly dimensioned Schmitz ring, which can readily withstand the static load and also, purely theoretically, the occurring shock loads, cannot in practice resist the dynamic continuous load mentioned when its body in the bearing border region is provided with axially-extending through bores. Clearly this is not necessarily because these bores weaken the bearing cross-section, for this could otherwise be compensated simply by the dimensioning and the choice of material. It seems to be of far more decisive significance that these axially-extending bores represent inconstancies in the transmission path of the mechanical stresses, where the occuring shock waves are reflected, so that they can build up inside the Schmitz ring body in an uncontrolled manner.

Thereby it can certainly happen that these shock waves, increasing very rapidly, can accumulate in such a way that they impair the material structure at certain foci. During sufficiently long and intensive loading, such points of disturbance can extend to the edge of the Schmitz ring, where it then leads to noticeable damage on its running surface.

The different natural frequencies also seem to play a certain role in this, which are inherent in the Schmitz ring regions between the individual bores.

By the measures according to the invention, such points of inconstancies in the peripheral region of the bearer ring and thus also uncontrolled stress peaks in the body interior are avoided. They have the further advantage that they enable the bearer ring to be improved with the aid of case hardening, without having to fear inner stresses, and through the choice of the material and the kind of treatment, to carry out material matching to allow for the different cylinder surfaces. Spacing the bearer ring from the end of the cylinder has the advantage that the driving shaft can be supported so that it is prevented from bending and that the running surface of the bearer ring does not come into contact so easily with aggressive washing age 1 ts during cleaning of the cylinders, which could likewise lead to an impairment of the running surface. The measures according to the invention allow the full width of the bearer ring to be used and to accommodate the two bearer rings of a printing machine cylinder in the case of normal machine width within its side walls.

It is advantageous to construct the central bores of the bearer ring in tapered form-like the outer race of a tapered roller bearing and to press it onto a correspondingly tapered part of the driving shaft of the cylinder. According to another preferred feature of the invention, the bearer ring is transversely divided into two or more ring segments so that it can be placed on the driving shaft of the cylinder from the sides.

This has the advantage that such a bearer ring can be exchanged without dismounting the cylinder, if the bearer ring has suffered damage, which introduces a considerable saving in repairing costs and a reduction in production lost during machine shut-down.

The invention may be carried into practice in a number of ways but certain specific embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figures 1 and 2 show a conventional Schmitz or bearer ring in side and end views respectively; Figures 3, 4 and 5 show three embodiments of Schmitz or bearer rings in accordance with the invention, in side view; Figure 6 shows the Schmitz or bearer rings of Figures 4 and 5 in end view; and Figures 7 and 8 show the Schmitz or bearer rings of Figures 4 and 5 with a different manner of attachment.

In Figures 1 and 2, a conventional Schmitz ring 1 is shown as has previously been used in rotary printing machines. It is attached to the front end of a printing machine cylinder 3 by means of screws 5, which are inserted through axially-extending bores 7 in the Schmitz ring 1. The Schmitz ring 1 has a central bore 9 so that it can be mounted on a driving shaft 11 of the printing cylinder 3, and is provided with further bores 13 and 15 of larger diameters than those of the bores 7, through which the clamping and setting devices located in the body of the printing cylinder 3 are accessible, which are indicated in Figures 1 and 2 only by bolts with recessed hexagonal holes 17 and 19.

As can be appreciated best from Figure 2, the Schmitz ring 1 thus has a plurality of contact areas inside, which are constituted by the walls of the bores 7, 9, 13 and 15 and which act as reflecting inconstancies for shock waves which during operation of the printing machine originate at and progress from the rolling contact surface 21 of the Schmitz ring.

In Figure 3, an embodiment of the invention is shown, which is free from such points of inconstancies. Here a Schmitz ring 25, by means of a central bore 27, which is tapered, is locate on a part 29, similarly tapered in form, of the driving shaft 11 of the printing machine cylinder 3. For this purpose, at several points in its circumference the shaft part 29 bears oil grooves 31, which can be connected to a source of oil (or other fluid) under pressure (not shown here) via bores 33, in order to expand the ring 25 elastically while it is being put on. The Schmitz ring 25 is held on the driving shaft 11 by a retaining washer 35 which partly overlies the front end face of the Schmitz ring, i.e.

that face remote from the cylinder 3, and is fastened to the shaft part 29 by screws 37.

By applying oil under pressure, the Schmitz ring 25 can be easily removed from the shaft part 29 so that this can be done quickly in case of emergency.

The Schmitz ring 25, except for its central bore 27, is completely free of any bores which would produce reflecting points for shock waves that would otherwise weaken and damage it. Disturbance-free operation can therefore be expected from the Schmitz ring and it should be as reliable in operation as the outer race of a roller bearing. In fact, a conventional outer race of a tapered roller bearing could be used as the Schmitz ring if it is of the appropriate outer diameter.

Figures 4 and 5 show two further embodiments in which the necessity of having to clamp the Schmitz ring on the driving shaft is facilitated by making the Schmitz ring in two or more parts so that it can be assembled on the driving shaft from the sides without having to dismount the entire printing machine cylinder for this purpose as is required for an undivided ring which has to be placed on the driving shaft over the end.

For this purpose, the Schmitz rings are each transversely divided into two or more ring segments and are each provided with clamping devices which connect the two or more Schmitz ring halves or segments together and at the same time fix them firmly to the driving shaft.

In Figure 4, a Schmitz ring 41 is transversely divided into two substantially half annular segments 45 and 47 fundamentally in a plane containing the axis of rotation. In order to achieve an overlapping rolling on the rolling contact surface 43 of the Schmitz ring 41 at the junction between both Schmitz ring halves 45 and 47, which achieves a transitional transfer of load from one half to the other, and two opposed ends of the Schmitz ring halves 45 and 47 at each side are constructed so that they interlock in the manner of saw teeth 49.

In the embodiment according to Figure 5, a Schmitz ring 51 is transversely divided into two half annular segments 55 and 57 in a parting plane passing at a relatively steep angle to the axis of rotation, so that two inclined planes at the opposed ends of the Schmitz ring halves 55 and 57 form respective parting faces 53, which achieve in similar manner a shock-free transfer of load during the rolling contact. So that the two Schmitz ring halves 55 and 57 cannot rotate relatively to each other, they are connected to the front surfaces of the Schmitz ring 51 or are provided with at least one of two stepped shoulders 59 and 61. These shoulders can, however, also be provided in the middle region of the parting faces 53.

In order to reduce still further the sudden transfer of load from one segment to another during rolling contact over the saw teeth 49 or over the parting faces 53, the measures according to Figures 4 and 5 can also be combined, i.e. the saw teeth 49 can be placed somewhat obliquely and the parting faces 53 can be constructed in the form of saw teeth.

The clamping devices for connecting the two part-annular ring segments are shown in Figures 5 and 6. The left half of Figure 6 relates to the arrangement according to Figure 5 and the right half to that according to Figure 4. The clamping devices here consist of two tensioning screws 65 and 67, which pass through respective bores 73 extending obliquely to the rotary axis as viewed in side elevation (Figure 5), between two correspondingly obliquely arranged and aligned openings 69 and 71 in the end faces of the Schmitz rings 41 and 51. The tensioning screws 65 and 67 are advantageously each constructed of two bolts 75 and 77, which can be screwed into each other.

The arrangements according to Figures 4 to 6 have in themselves the disadvantage that the body of each Schmitz ring 41 and 51 is again provided with attachment openings.

The latter, however, have no noticeable effect on the dynamic continuous running condition of the rings, because these openings with their most operative part, the bore 73, pass deep in the central region in the Schmitz ring body.

Above all, however, they are placed obliquely so that they cannot form any continuous shock waves.

However, it is alternatively readily possible to clamp the Schmitz ring halves 45, 47 and 55, 57 on the driving shaft 11 without such attachment openings 69, 71 and bores 73.

Two such possibilities are illustrated in Figures 7 and 8. There the Schmitz rings 41, 51 are provided with tapered spigots formed by annular projections 80 and 81, 90 and 91 on their end faces by means of which they can be tightened and pressed against the driving shaft 11. These projections 80, 81, and 90, 91 are transversely divided like the Schmitz rings 41 and 51 and each partannular projection is constructed integrally with the respective Schmitz ring half 45, 47, or 55, 57.

In order to press the two Schmitz ring halves 45 and 47 together, two tapered rings 82 and 83 are used in the arrangement according to Figure 7, which are positioned on the driving shaft 11 and which bear upon the tapered projections 80 and 81 with tapered inner surfaces 84 and 85. The tapered ring 83 nearer the printing machine cylinder 3 rests against an axially facing shoulder 12 of the driving shaft 11 and the other tapered ring 82 is pressed in the direction towards the shoulder 12 by a ring nut 87 screwed onto a screw-thread 86 of the driving shaft 11, so that the two Schmitz ring halves 45 and 47 are firmly tightened and pressed against the driving shaft 11. When tightened, the ring nut 87 is secured against rotation relative to the shaft 11 by a locking washer 88, disposed, so that it will not turn, between the ring nut 87 and the tapered ring 82, parts of the circumference of the washer engaging into recesses or other abutments 89 of the ring nut 87.

In the arrangement according to Figure 8, a tapered nut 92 is provided for the same purpose in conjunction with the tapered ring 83 resting against the shoulder 12 and bearing on the tapered projection 91 of the Schmitz ring 51 with its tapered inner surface 85, the tapered nut 92 bearing for its part on the tapered projection 90 with a tapered inner surface 94 and being screwed onto a screwthread 96 of the driving shaft 11. The ring nut 92 is provided with an annular slot 97 in the region of the screw-thread 96 of the driving shaft 11 so that the nut 92 can be axially compressed by at least one screw 98 inserted in a hole from the front face of the tapered nut 92, so that the latter can be locked onto the screw-thread 96 and thereby be secured against rotation relative to the drive shaft 11.

The manner of attachment of the Schmitz ring halves according to Figure 7 or 8 is, of course, independent of whether the Schmitz rings have been divided transversely according to Figure 4 or according to Figure 5 or in any other way.

As is necessary in all Schmitz ring arrangements, each of the illustrated bearing rings is mounted for rotation with the respective cylinder.

ln Figure 6, two tensioning screws 65, 67 are provided. However, arrangements are possible in which only one tensioning screw is providcd.

WHAT WE CLAIM IS: 1. A cylinder for a rotary printing machine carried co-axially by a driving shaft, and a bearer ring therefor, the bearer ring being intended, in usc, to make rolling contact with another bearer ring associated with another cylinder to determine the distance between the axes of the cylinders, the bearer ring having a central, axially-extending through bore by which the ring is mounted co-axially on the driving shaft of the cylinder for rotation therewith, at a position spaced axially from the adjacent end of the cylinder, the bearer ring otherwise having no axiallyextending bores therein.

2. A cylinder and bearer ring as claimed in claim 1, in which the central bore of the bearer ring is tapered and is engaged over a correspondingly tapered part of the driving shaft of the cylinder.

3. A cylinder and bearer ring as claimed in claim 2, in which the bearer ring comprises an outer race of a tapered roller bearing.

4. A cylinder and bearer ring as claimed in claim 2 or claim 3, in which a locking washer at least partly overlies the end face of the bearer ring remote from the cylinder and is removably secured to the tapered part of the driving shaft thereby to retain the bearing ring removably on the driving shaft.

5. A cylinder and bearer ring as claimed in any one of claims 2 to 4, in which the tapered part of the driving shaft has, as at least some regions of its circumference, grooved or recessed portions connected to bores for supplying fluid under pressure.

6. A cylinder and bearing ring as claimed in claim 1, in which the bearer ring is transversely divided into two or more ring segments whereby it can be placed on the driving shaft of the cylinder from the sides.

7. A cylinder and bearer ring as claimed in claim 8, in which the bearer ring is transversely divided into two substantially halfannular segments generally in a plane containing the axis of rotation and the two opposed ends of the two bearer ring halves are constructed to interlock in a saw tooth form.

8. A cylinder and bearer ring as claimed in claim 6, in which the bearer ring is transversely divided into two substantially halfannular segments generally in a plane inclined to the axis of rotation.

9. A cylinder and bearer ring as claimed in claim 8, in which the bearer ring segments each include at least one stepped shoulder which co-operate to prevent relative rotation of the ring segments, the stepped shoulders being provided respectively in the two parting faces of the ring segments.

10. A cylinder and bearer ring as claimed in any one of claims 6 to 9, in which the bearer ring includes at least one tensioning screw connecting the two halves of the bearer ring.

11. A cylinder and bearer ring as claimed in any one of the claims 6 to 9, in which the bearer ring has two tapered spigots which project axially beyond the two end faces of the bearer ring, over which spigots tapered inner surfaces of two retaining rings positioned on the driving shaft overlie, of which the retaining ring adjacent the cylinder is supported against a shoulder of the driving shaft and the retaining ring remote from the cylinder is adapted to bear onto the corresponding spigot of the bearer ring in a direction towards the shoulder.

12. A cylinder and bearer ring as claimed in claim 11, in which the retaining ring remote from the cylinder can be tightened against the corresponding spigot of the bearer ring by a ring nut engaged on a screw-thread on the driving shaft.

13. A cylinder and bearer ring as claimed in claim 12, in which between the ring nut and the retaining ring remote from the cylinder a locking washer is disposed which cooperates with the ring nut to prevent rotation of the latter relative to the driving shaft.

14. A cylinder and bearer ring as claimed in claim 11, in which the retaining ring

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. into recesses or other abutments 89 of the ring nut 87. In the arrangement according to Figure 8, a tapered nut 92 is provided for the same purpose in conjunction with the tapered ring 83 resting against the shoulder 12 and bearing on the tapered projection 91 of the Schmitz ring 51 with its tapered inner surface 85, the tapered nut 92 bearing for its part on the tapered projection 90 with a tapered inner surface 94 and being screwed onto a screwthread 96 of the driving shaft 11. The ring nut 92 is provided with an annular slot 97 in the region of the screw-thread 96 of the driving shaft 11 so that the nut 92 can be axially compressed by at least one screw 98 inserted in a hole from the front face of the tapered nut 92, so that the latter can be locked onto the screw-thread 96 and thereby be secured against rotation relative to the drive shaft 11. The manner of attachment of the Schmitz ring halves according to Figure 7 or 8 is, of course, independent of whether the Schmitz rings have been divided transversely according to Figure 4 or according to Figure 5 or in any other way. As is necessary in all Schmitz ring arrangements, each of the illustrated bearing rings is mounted for rotation with the respective cylinder. ln Figure 6, two tensioning screws 65, 67 are provided. However, arrangements are possible in which only one tensioning screw is providcd. WHAT WE CLAIM IS:

1. A cylinder for a rotary printing machine carried co-axially by a driving shaft, and a bearer ring therefor, the bearer ring being intended, in usc, to make rolling contact with another bearer ring associated with another cylinder to determine the distance between the axes of the cylinders, the bearer ring having a central, axially-extending through bore by which the ring is mounted co-axially on the driving shaft of the cylinder for rotation therewith, at a position spaced axially from the adjacent end of the cylinder, the bearer ring otherwise having no axiallyextending bores therein.

remote from the cylinder carries an internally screw-threaded portion which engages a screw-thread on the driving shaft.

15. A cylinder and bearer ring as claimed in claim 14, in which the retaining ring remote from the cylinder has an annular slot in the region of the screw-thread which can be tightened by at least one screw which can be inserted into the retaining ring in this region.

16. A cylinder for a rotary printing machine and a bearer ring therefor, substantially as specifically described herein with reference to any one of the embodiments shown in Figures 3 to 8 of the accompanying drawings.

17. A rotary printing machine having a cylinder and a bearer ring therefor, as claimed in any one of the preceding claims.

18. A bearer ring for use in conjunction with a cylinder of a rotary printing machine, having the features as defined in any one of claims 7 to 11 or as shown in any one of the embodiments illustrated in Figures 3 to 8 of the accompanying drawings.