GB2097505A - Distributor roller assembly with a variable stroke axially reciprocating roller - Google Patents

Abstract

A distributor roller assembly is provided with means for adjusting the stroke of an axially reciprocable distributor roller (1), the adjusting means comprising a rotatably drivable shaft (3) which is installed on the roller (1) outside a wall (2) of the assembly and is provided at each of its ends with a respective crank disc (6, 7) each carrying a respective crank pin (8, 9). The two crank pins (8, 9) are disposed at different distances from the axis of the shaft (3) and each of them is rotatably connected to a connecting rod (10 or 11) at one end thereof. The other end of each connecting rod is rotatably connected to a pin (12 or 13) which is fixed on a slide pin (14 or 15) engaged either in a respective bore (18 and 19) in a cover plate (17) fixed to and spaced from the wall (2) or in a respective bore in the wall itself. Optionally either the one or the other slide pin (14 or 15) can be locked, fixed in one plane, in the cover plate (17) or the wall (2) and at the same distance from the associated crank pin (8 and 9). <IMAGE>

Description

SPECIFICATION Distributor roller assembly with a variable stroke axially reciprocating roller The present invention relates to a distributor roller assembly with a varable stroke axially reciprocating distributor roller, especially for spreading ink on an inking roller in an inking mechanism of a rotary printing machine.

In DE-PS 185 198 there is disciosed an arrangement in which the axial movement of a roller is effected by a space-saving crank gear disposed in a hollow cavity of the roller. The adjusting of the axial stroke of the roller is achieved by adjusting a crank pin relative to the rotational axis of a crank disc carrying the pin. The crank pin is fixed on a slide, which is guided in a groove in the crank disc and is adjustable by means of a threaded spindle.

This arrangement is very expensive to manufacture, and the guiding of an associated connecting rod in an annular groove of the roller and the guiding of the slide in the crank disc are almost impossible to realize without play.

Moreover, the sliding guidance of the connecting rod in the annular groove of the roller, provided in the revolving roller, is subject to high wear and as a result the device is not sutiable for high-speed machines.

A further disadvantage consists in the complicated and difficult adjustment facility of the slide and thus of the stroke by the threaded spindle, access to which is difficult to gain with tools. Since, with few exceptions, all reciprocating drives are equipped with guards, these have to be opened or removed for the adjustment of the threaded spindle. With this is associated the risk that due to inattention tools could fall into other machine drive components still partly covered and lead to accidents.

In DE-GM 7 222 220 there is disclosed a device for the axial rubbing motion of two distributor rollers oscillating relative to each other.

With the assistance of a complicated gear unit disposed in the drive of this device, a displacement of the phase position in respect of the rubbing motion of the two rollers relative to the rotational motion of the plate cylinder is intended to be achieved. The problem of the necessary or observable phase position arises, however, due to the large clamping channei in the plate cylinder, only in sheet printing machines. A separate stroke adjustment of the disbributor rollers is not possible. A further disadvantage of this device is the amount of space required for the drive section, which cannot be housed on the drive side of a rotary printing machine.

In DE-PS 23 36 061 there is described a drive of two distributor rollers transversely oscillating simultaneously in one direction. The two rollers are each connected with a connecting rod (or crank rod), each of which isjournalled on a crank pin of a crankshaft at a different distance from the rotational axis of a crankshaft. In this arrangement, due to the different axial distances, one distributor roller has a smaller stroke than the other. This arrangement also cannot be accommodated, due to the large amount of space needed, on the drive side of a rotary printing machine, but only with some difficulty on the opposite side of the machine. Moreover, due to the complicated construction, additional supporting and bearing costs are entailed.

A separate adjustment of the reciprocation stroke is not possible with either of the two rollers.

In this arrangement, the reversal points of the axial movement of the rollers are intended to lie at one and the same position relative to the plate circumference, solely with the objective of achieving a faultless print.

The demands in respect of construction, space and cost in reciprocating drives for the simultaneous operating of a plurality of distributor rollers proves unsuitable in the majority of cases, due to the afore-mentioned disadvantages. By contrast, individual driving of the rollers possess quite a number of advantages, and the aforementioned problems of phase position and reversal points can, where this is required, be solved by the individual adjustment for each case.

In particular, a requirement that arises in simple newspaper printing could be fulfilled by arranging the reciprocation stroke to be variable between two stroke lengths, because it has been found that a long stroke is advantageous especially where on ink is used on the cylinder, above all in panorama printing, whereas a short stroke offers advantages with a number of inks adjacent to one another in the ink duct, especially where decorative inks are used, in particular in respect of the maximum utilization of the printable paper surface.

There is accordingly a need for adjusting means for adjustment of the axial reciprocation stroke of a distributor roller for, in particular, a high-speed rotary printing machine used in newspaper printing. The adjusting means should preferably be capable. of being manufactured at low expense and have good reliability with low wear. The driving and mounting of the elements for effecting the axial reciprocation should preferably be effected in such a manner that only an insignificant amount of bearing play and wear arises. Adjustment to the desired stroke length should expediently be possible even with a protective guard closed, and, even with strokes of different length, the central position of the distributor roller relative to, for example, a cooperating inking roller should be maintained.

According to the present invention there is provided distributor roller assembly comprising a distributor roller mounted between support means for axial reciprocating movement relative thereto, a rotatably drivable cross shaft connected to an extension of the roller outside the support means, a respective crank pin connected to the shaft at each end thereof, the crank pins being arranged at respectively different spacings from the shaft axis, a respective connecting rod rotatably connected at one end thereof to each crank pin, a respective slide element pivotably connected to each connecting rod at the other end thereof and engaged in a respective bore defined by means having a fixed position relative to the support means, and securing means for securing a selectable one of the slide elements against movement relative to the support means thereby to determine the stroke of the roller, the slide elements being securable in the same plane and at the same distance from the associated crank pin.

In a preferred embodiment, the shaft is drivably installed at the distributor roller outside a machine wall, the shaft being equipped at each end with a respective crank disc carrying one of the crank pins and the two crank pins being disposed on the discs at different distances from the shaft rotational axis. The shaft disposed on the roller and provides, with simultaneous use of the roller for mounting of some drive components of the crank drive, optimum utilization of the space available and creates the condition where the reciprocating drive of the roller can be housed on the side of the apparatus from which the roller is rotationally driven.

For preference, each of the crank pins is rotatably connected to bearing means of a respective one of the connecting rods, further bearing means of each rod being rotatably connected to a pin which is attached to a journal pin acting as the slide element. Such a connection of the individual drive elements avoids, by the rotatable arrangement, sliding guidance, for example in guide grooves. It is therefore possible to use at the connecting points of the individual drive elements known wear-resistant and clearance-free bearings. Each of the two journal pins is guided, with a piston-shaped portion thereof, in a bore of a cover plate fixed at a distance to the machine wall, or in a bore provided for this purpose in the machine wall, and can be fixed to the cover plate or to the machine wall as the case may be in a common plane and at an equal distance from the associated crank pin.It is thus possible for the journal pin belonging to the selected crank drive to be fixed from outside, for example by a screw, without opening a protective guard of the apparatus. In this way a rapid adjustment facility for the stroke is provided and yet it is no longer possible for tools to be accidentally dropped into drive components and thereby cause damage.

Only the secured crank drive effects reciprocation of the distributor roller, as the other crank drive, which executes a different stroke from the secured drive, idles.

Advantageously, the distance at the connecting rod journalled on each crank pin, from the crank pin to the end of the journal pin, is of equal size and each journal pin can be fixed in the same plane. It is thereby possible that at each set stroke the movement of the friction roller relative to, for example, an inking roller always osciilates about the same central position.

On the outer face of the cover plate, a locking plate can be mounted to be pivotable about an axis which lies medially between the axes of two bores of the cover plate. The plate is provided with an opening which, after pivoting through 1 800, can be brought into a position aligned with a threaded hole in a respective one of the two journal pins. The selected journal pin can now be fixed to the locking plate, for example by means of a screw.

The arrangement of the pivotal plate is provided for, in particular, safety reasons by serving to prevent operator error, such as simultaneously locking both journal pins to the cover plate.

In order to prevent such simultaneous locking of the journal pins in the case where the pins are guided in bores in the machine wall itself, an annular segment may be mounted rotatable about the distributor roller on the inner face of the machine wall, the segment having an opening which can be brought into alignment with one of the bores and, by rotating the segment, with the other such bore.

The segment can be firmly connected by means of a screw to the journal pin in the bore with which the segment opening is aligned.

Embodiments of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a cross-sectional view, on the line A-A of Fig. 2, of part of a distributor roller assembly according to a first embodiment of the invention; Fig. 2 is an end view of the assembly of Fig. 1, in the direction of arrow B in Fig. 1; Fig. 3 is a cross-sectional view similar to Fig. 1 but of part of a distributor roller assembly according to a second embodiment of the invention; Fig. 4 is an inverted plan view of the assembly part of Fig. 3, in the direction of arrow C in Fig. 3; and Fig. 5 is a schematic representation of the reciprocatory movement of a distributor roller of an assembly embodying the invention in relation to an inking roller associated with the assembly.

Referring now to the drawings, there is shown part of the inking mechanism of a rotary printing machine, the inking mechanism comprising an inking roller and a distributor roller 1 mounted between machine walls 2 for axial reciprocation relative to the inking roller so as to spread ink over the inking roller by rubbing contact therewith. At one end of the distributor roller 1, a shaft 3 is rotatabiy mounted thereon outside one of the machine walls 2. The shaft 3 is mounted in two bearings 4, between which a worm wheel 5, rotationally drivable by a worm (cf. Fig. 4), is securely keyed to the shaft. The discs 6 and 7 are keyed to the shaft one at each end thereof so as to be rotatable with the shaft. Fixed to the discs 6 and 7 are, respectively, two crank pins 8 and 9, which are disposed at respectively different distances from the axis of rotation of the shaft 3.

Two connecting rods 10 and 1 each provided with a bearing at each end thereof, are rotatably connected to the crank pins 8 and 9, respectively, by the bearings at the lefthand (seen in Fig. 1) ends of the rods. The other bearings of the two connecting rods 10 or 11 are rotatably seated on pins 1 2 and 13, respectively, which are fixed to journal pins 14 and 15, respectively. In the present embodiment, the pins 14 or 1 5 are piston-shaped and are provided at the crown of the piston with a threaded hole 16. The journal pins 14 and 1 5 are guided by their piston-shaped portion in two bores 1 8 and 19, respectively, provided in a cover plate 17 or, as can be seen in Fig. 3, in bores 20 and 21 in the machine wall.The cover plate 1 7 is fixed by a number of stud bolts 22 to the machine wall.

The pins 14 and 1 5 can be selectively secured in the same plane to a plate 24 (Figs. 1 and 2), which is rotatablyjournalled on a pin 23 outside the cover plate 17, or to an annular segment 25 (Fig. 3). The plate 24 is provided with a bore 25 which, by pivoting the plate 24 through 1800, can be brought into alignment either with the bore 1 8 or with the bore 19 in the cover plate 17. The fixing of a pin 14 or 1 5 to the plate 24 is effected by means of a screw 27.

If the two pins 14 and 15 are, as shown in Fig.

3, guided in bores 20 and 21 in the machine wall, then for the purpose of fixing the relevant pins 1 4 or 1 5 in the required plane, the annular segment 25 is mounted to be rotatable and is capable of being fixed on the inner face of the machine wall.

The segment 25 is, like the plate 24, furnished with a bore 28 which, if the segment is rotated, can be brought into aligment either with the bore 20 or with the bore 21. The fixing of the pin 14 or 1 5 is effected through the bore 28 by means of the screw 27.

If the distributor roller 1 is to oscillate for the use of one ink on the cylinder at the longer stroke, then according to Fig. 1 the journal pin 14 is locked to the plate 24. Thus the crank drive, the crank pin 8 of which is at the larger distance from the axis of rotation of the shaft 3, is fixed to the plate 24. For this purpose the plate 24 will have been previously rotated so that its bore 26 is in alignment with the bore 18 of the cover plate 17.

The pin 14 can then be fixed by means of the screw 27 to the plate 24. The plate 24 can be firmly connected to the cover plate 1 7. If it is provided, as shown in Fig. 3, for the pins 1 4 and 15 to be guided in the bores.20 and 21, in the machine wall itself, then for the longer stroke the pin 14 is fixed by the screw 27 to the annular segment 25, which can be firmly connected to the machine wall. The crank drive fixed in this manner causes the roller 1 to be moved in an oscillating motion, with the longer stroke, axially of the inking roller, while the crank drive having the unfixed pin 1 5 idles, its piston-shaped portion oscillating in the bore 1 9 or 21, as the case may be, provided with a slide bearing bushing.

If the smaller stroke would provide greater advantages for the particular use, then the screw 27 is removed from the threaded hole 1 6 of the pin 14 and, depending upon the embodiment according to Fig. 1 of Fig. 3,the fixing to the plate 24 on the cover plate 17 or to the segment 25 situated on the machine wall is released. The plate 24 or segment 25 is then pivoted until, in the case of the plate 24 the bore 26 is aligned with the bore 19 in the cover plate 1 7, or in the case of the segment 25 its bore 28 is aligned with the bore 21 in the machine wall.

Subsequently, by means of the screw 27, the other pin 1 5, which is distant from the common plane by the difference between the larger and smaller axial distances of the crank pins 8 and 9 from the shaft 3, is pulled into the common plane and is fixed to the plate 24 or to the annular segment 25.

The selection fixing of the journal pins 14 and 1 5 in one plane offers the advantage that, at each of the two stroke adjustments, the distributor roller 1 oscillates about the same axial centre of the inking roller.

Claims (9)

1. Distributor roller assembly comprising a distributor roller mounted between support means for axial reciprocating movement relative thereto, a rotatably drivable cross shaft connected to an extension of the roller outside the support means, a respective crank pin connected to the shaft at each end thereof, the crank pins being arranged at respectively different spacings from the saft axis, a respective connecting rod and rotatably connected at one end thereof to each crank pin, a respective slide element pivotably connected to each connecting rod at the other end thereof and engaged in a respective bore defined by means having a fixed position relative to the support means, and securing means for securing a selectable one of the slide elements against movement relative to the support means thereby to determine the stroke of the roller, the slide elements being securable in the same plane and at the same distance from the associated crank pin.

2. An assembly as claimed in claim 1, wherein the shaft is provided at each end thereof with a respective disc, the crank pins being mounted on the discs.

3. An assembly as claimed in either claim 1 or claim 2, wherein the bores are defined in a cover plate secured to and disposed at a spacing from the support means.

4. An assembly as claimed in claim 3, the securing means comprising a locking plate which is mounted on the cover plate to be pivotable about an axis medially between the axes of the bores receiving the slide elements and which is provided with an opening selectively alignable with the bores by pivotable movement of the locking plate and adapted to receive fastening means fastenable to the slide element engaged in a bore so aligned.

5. An assembly as claimed in either claim 1 or claim 2, the support means comprising wall means of the assembly and the bores being defined in the wall means.

6. An assembly as claimed in claim 5, the securing means comprising an arcuate member mounted on the wall means to be rotatable about an axis of the roller and provided with an opening which is selectively alignable with the bores by rotational movement of the member and is adapted to receive fastening means fastenable to the slide element engaged in a bore so aligned.

7. An assembly as claimed in either claim 4 or claim 6, the fastening means comprising a threaded member.

8. Distributor roller assembly substantially as hereinbefore described with reference to Figs. 1, 2 and 5 of the accompanying drawings.

9. Distributor roller assembly substantially as hereinbefore described with reference to Figs. 3 to 5 of the accompanying drawings.