Apparatus for the displacement of bearing blocks mounted on carriages and which support shafts

In an apparatus for the displacement of bearing blocks mounted on carriages which support shafts, a first carriage is carried for displacement in a carriage guideway fixed to the frame, and the other carriage is carried in a carriage guideway of the first carriage, these two carriage guideways being mutually parallel. To allow the carriages to be displaced with sufficient accuracy without expensive control devices, two spindle screw nuts designed as toothed belt pulleys are mounted in the first carriage parallel to each other and freely rotatable, and the screw spindles screwed into them are mounted selectively for free rotation and for being fixed, on the one hand in the machine frame and, on the other hand, in the second carriage. In the first carriage there is mounted a further drive belt pulley that is drivable by a motor and securable by a securing device, this further drive belt pulley driving an endless toothed belt that drives said spindle screw nuts designed as toothed belt pulleys.

FIELD OF THE INVENTION 
The invention relates to an apparatus for the displacement of 
shaft-supporting bearing blocks mounted on carriages of which a first 
carriage is carried for displacement in a carriage guideway fixed to the 
frame and a second carriage is carried in a carriage guideway of the first 
carriage, which is parallel to the carriage guideway fixed to the frame, 
preferably for the displacement of the bearing blocks of plate cylinders 
and inking rollers of a printing unit in a multicolour rotary printing 
press. Two screw spindle drives provided with motors displace the 
carriages. 
PRIOR ART 
Flexographic printing presses with carriage guideways for the plate 
cylinders and inking rollers of the above mentioned kind are known for 
example, from the DE-A-29 41 521, DE-A-34 37 216, DE-A-37 42 129 and 
DE-A-40 01 735. 
In an apparatus known from DE-GM 92 09 455 for the displacement of 
carriages carrying plate cylinders and inking rollers, both carriages are 
carried in a common carriage guideway of the frame of the flexographic 
printing press. In such arrangement each carriage is provided with its own 
screw spindle and its own screw spindle drive. This known apparatus 
requires an expensive control for the motors driving the screw spindles, 
necessitating an expensive electronic control system. 
OBJECT OF THE INVENTION 
It is, therefore, an object of the invention to provide an apparatus of the 
kind indicated in the opening paragraph above, wherein the carriages can 
be displaced with sufficient accuracy without expensive control devices, 
so that the apparatus can be used to particularly good advantage in 
smaller printing presses. 
SUMMARY OF THE INVENTION 
In accordance with the invention, there is provided an apparatus for the 
displacement of bearing blocks mounted on shaft supporting carriages, of 
which a first carriage is carried for displacement in a carriage guideway 
fixed to the frame, and the other carriage is carried in a carriage 
guideway of the first carriage, said carriage guideways being mutually 
parallel, preferably for the displacement of the bearing blocks of plate 
cylinders and inking rollers, of a printing unit of a multicolour rotary 
printing press which has two screw spindle drives displacing the carriages 
and is provided with a motor drive, including:- two spindle screw nuts 
designed as toothed belt pulleys mounted in the first carriage parallel to 
each other and for free rotation; the screw spindles of said drives being 
screwed into the nuts and mounted selectively for free rotation for being 
fixed against rotation; one of said screw spindles being further mounted 
in the machine frame and on the other of said screw spindles being further 
mounted in the second carriage; and a further toothed belt drive pulley in 
the first carriage drivable by a motor and securable by a securing device, 
said further toothed belt pulley driving an endless toothed belt that 
drives the first-mentioned toothed belt pulleys. 
If this apparatus is used as a screw spindle drive for the plate cylinder 
carriages and the inking roller carriages of a flexographic printing 
press, the carriages can be displaced relative to the machine frame by 
means of the toothed belt drive if the screw spindles are respectively 
mounted so as to be secured against rotation on the frame or the inking 
unit carriage, in such a way that the inking unit carriage moves relative 
to the frame at twice the speed of the plate cylinder carriage. This means 
that when the plate cylinders and inking unit rollers have been removed 
from their common impression cylinder, the plate cylinder can be changed 
in a simple way. The arrangement is such that the cylinders, when 
positioned in the printing operation, assume a position relative to each 
other wherein the plate cylinder is in contact with the impression 
cylinder and the inking roller is in contact with the plate cylinder. Of 
course a fine adjustment may still be necessary and can, for example, be 
effected in that the screw spindles are provided at one end with knobs 
that are actuable by hand. In this fine adjustment, the screw spindle 
clamping devices on the frame or on the inking unit carriage must, of 
course, be released and the spindle screw nuts designed as toothed belt 
pulleys have to be blocked by means of the toothed belt drive. 
The securing devices for the screw spindles and the shaft of the toothed 
belt drive pulley consist expediently of braking or clamping jaws that are 
movable by motor means. 
In a further development of the invention, provision is made for the hub of 
the toothed belt drive pulley to be provided with an annular groove 
extending over a portion of its circumference, into which a securing pin 
may be inserted and from which it may be extracted. Thus when the pin is 
inserted, the toothed belt drive pulley is capable of executing a limited 
rotation of, for example, approximately 250 degrees by being driven by a 
motor; this is sufficient for the displacement of the cylinders for the 
"printing-on" and "printing-off" selection operations. 
The drive motor for the toothed belt drive pulley consists expediently of a 
pneumatic motor which readily stalls when the pin projectable into the 
annular groove abuts against one of the two stops. 
Instead of a toothed belt driving the spindle screw nuts, provision may of 
course be made for a transmission of a different kind, for example a gear 
wheel system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows the carriage 13 for the plate cylinder 14 mounted for 
displacement on a bracket 3 of the frame 2 of a flexographic printing 
press. On this carriage 13, the carriage 16 for the inking roller 15 is in 
turn mounted for displacement in a carriage guideway. The flexographic 
printing press, of which the carriage guideways and carriage drives form 
part, is of a per se known design, as known for example from the DE-A-29 
41 521, DE-A-34 37 316, DE-A-37 42 129 and DE-A-40 01 735, the disclosures 
of which are incorporated herein by reference for a more detailed 
explanation of the basic design of flexographic printing presses. 
The impression cylinder 1 is mounted in the usual way in the printing press 
frame 2, onto which are screwed the individual brackets 3, one of which is 
shown in FIG. 1. On its end remote from the frame stand 2, the bracket 3 
has a bent extension 4 which is provided with a bore to receive a screw 
spindle 5 rotatably mounted by means of roller bearings in the way shown. 
By means of a spindle clamping device shown in FIG. 3, the screw spindle 5 
can be secured against rotation if required. 
In its simplest design, the clamping device consists, as shown in FIG. 3, 
of a supporting component 8 joined to the bracket 3 and provided with a 
bore 8' receiving an untapped end portion of the screw spindle 5. In this 
arrangement, the bore 8' is provided with an open slot between two 
jaw-defining extensions 7. These jaw-defining extensions 7 can be moved 
closer together and be separated by a pneumatic cylinder 7' whose cylinder 
is connected to one jaw and its piston rod to the other jaw. 
The end of the screw spindle 5 remote from the clamping device carries a 
manual turning knob 9. A toothed belt pulley 10 with an extension 11 is 
disposed on the screw spindle 5. By means of this extension 11, the 
toothed belt pulley 10 is mounted rotatably in an end plate 12, and the 
arrangement is such that the end plate 12 forms part of the plate cylinder 
carriage 13. This plate cylinder carriage 13 carries the plate cylinder 14 
in a manner known per se. In the embodiment shown, the plate cylinder 
bears on the one hand, on the impression cylinder 1 and, on the other 
hand, on the inking roller 15. The inking roller 15 is supported on the 
carriage 16 which is displaceable relative to the plate cylinder carriage 
13. A further screw spindle 17 is mounted at one end in the inking roller 
carriage 16, and carries a manual turning knob 18 on the free end of this 
screw spindle 17. In the vicinity of this knob 18, a toothed belt pulley 
20, provided with an extension 19, is fitted on the screw spindle 17 and 
has its inner thread meshing with the thread of the screw spindle 17. The 
toothed belt pulley 20 is mounted rotatably in the end plate 12 via the 
extension 19. A spindle clamping device 21, similar to the clamping device 
6 on spindle 5, is also assigned to the screw spindle 17 and is secured 
against rotation by means of a holder 22 connected to the inking roller 
block 16. 
FIG. 1 shows, moreover, that a common toothed belt 23 wraps round both 
toothed belt pulleys 10 and 20 and additionally also wraps round the drive 
belt pulley 24. This pulley 24 has several recesses, and is rotatably 
mounted by means of its extension 25 in a removable cover 26 of a frame 
housing 27 forming part of the end plate 12. A pneumatic motor 29, rigidly 
joined to the right-hand wall 28 of the housing 27, has its drive shaft 30 
connected to the drive belt pulley 24. In the drive pulley 24, there is, 
moreover, mounted a shaft 31 which is secured against rotation relative to 
the drive pulley 24 by means of a feather key 32. The end of the shaft 31 
projecting from the removable cover 26 co-operates with a further spindle 
clamping device 33 which is secured against rotation by means of a holder 
34 rigidly connected to the cover 26. 
The pneumatic motor 29 can, for example, be a compressed air motor type 2 
DM5, described on page 52 of the April 1989 catalogue of the firm of 
Desoutter GmbH of 6457 Maintal 3, Germany. 
Although not evident from the drawings, to ensure that the toothed belt 23 
wraps round the toothed belt pulleys 10, 20 and 24 with a good grip, the 
top toothed belt drive pulley 24 is arranged with a lateral offset 
relative to the toothed belt pulleys 10, 20. 
As is clearly evident in FIG. 2, the toothed belt pulley 24 is provided 
with a groove 35 extending over approximately 250 degrees, and into which 
there projects a retractible pin 36. This pin is mounted in a tubular 
component 37 which has a slot 38. A peg 39 rigidly connected to the pin 36 
projects radially outwardly into this slot. By means of a handle part 40 
joined to one of its ends, the pin 36 can be pulled out of the groove 35 
against a resilient force and then be secured in the retracted position by 
rotation of the handle 40, so that the peg 39 then bears on the upper edge 
of the tubular component 37. 
Now if, for example, the inking unit shown in FIG. 1 is to be moved into 
the "printing-off" position, the spindle clamping devices 6 and 21 are 
activated and the spindle clamping device 33 is released. The pneumatic 
motor 29 is then energised with compressed air, and rotates the toothed 
belt drive pulley 24 through approximately 250 degrees which is the 
limited rotational angle permitted by the pin 36 (FIG. 2) bearing against 
the stop surface 41 at the end of the groove 35 of the toothed belt pulley 
24 and thus preventing any further rotation. During this rotational 
movement, the toothed belt pulleys 10, 20 have of course also been 
rotated-through the corresponding angle by the toothed belt 23. Since the 
screw spindles 5 and 17 are secured against rotation, they have moved so 
far leftwards that on the one hand, the plate cylinder 14, carried by the 
plate cylinder block 13, has been lifted off to a small extent from the 
impression cylinder 1 by means of rotation of the screw spindle 5 and, on 
the other hand, the inking roller 15 has been released to a small extent 
from the plate cylinder 14 by means of rotation of the screw spindle 17 
driving and the plate cylinder block 13. For example, as soon as an 
adhesively secured join in the web to be printed has passed through the 
gap between the plate cylinder 14 and the impression cylinder 1 with the 
cylinder i held-off, the pneumatic motor 29 is operated to rotate the 
toothed drive belt pulley 24 until the drive belt pulley 24 has reached 
the position shown in FIG. 2. In this position, the plate cylinder 14 and 
the inking roller 15 have also reached their printing position. 
If a change of the plate cylinder 14 is required, the pin 36 (FIG. 2) is 
retracted from the groove 35 and secured. Thereupon the pneumatic motor 29 
is actuated so that, with the spindle clamping devices 6 and 21 activated 
to clamp the spindles 5 and 17, the plate cylinder carriage 13 and the 
inking roller carriage 16 are moved far enough leftwards and for it to be 
possible, for example, to insert a larger plate cylinder 14 as well. After 
the plate cylinder 14 has been changed, the pneumatic motor 29 is again 
operated, in the opposite direction of rotation until the new plate 
cylinder 14 has come to bear on the impression cylinder 1 and the inking 
roller 15 to bear on the plate cylinder 14. The pneumatic motor 29 is now 
switched off. 
Since, however, the inking roller 15 and the plate cylinder 14 are still in 
contact with an indeterminate pressure, a fine adjustment is required. For 
this purpose, the pin 36 (FIG. 2) is unbolted and moved down to be 
inserted in the groove 35. Since the position of the toothed drive belt 
pulley 24 is completely undefined, it is quite uncertain at which point 
the pin 36 engages in the groove 35 or even whether it is in register with 
this groove at all. To ensure that the pin 36 does actually become located 
in the groove 35, the pneumatic motor 29 is run for a short time in the 
"printing off" rotational direction until one ensures, for example by a 
visual check, that the pin 36 is actually inserted in the groove 35 and 
assumes the abutment position shown in FIG. 2. Thereupon the spindle 
clamping device 33 is activated and the two other clamping devices 6 and 
21 are released. Now, firstly, the inking roller 15 is moved towards the 
plate cylinder 14 by turning the manual knob 18 until proper inking is 
obtained. Then, the plate cylinder 14 is moved towards the impression 
cylinder 1 by turning the manual knob 9 until a proper printing quality is 
achieved. During this adjustment, the position of the inking roller 15 
relative to the plate cylinder 1 will not be altered, since the toothed 
belt pulleys 10 and 20 are both secured against rotation by means of the 
toothed belt 23, and by means of the activated spindle clamping device 33. 
After these adjustment operations, the spindle clamping devices 6 and 21 
are activated to clamp the spindles 5 and 17, whereby the position of the 
plate cylinder 14 and of the inking roller 15 are secured. The printing 
may be started. Now if the "printing-off" position is to be entered, this 
is done, as has already been described at the outset, by releasing the 
clamping device 33 and by means of operating the pneumatic motor 29 to 
rotate the toothed drive belt pulley 24 by approximately 250 degrees. 
Reference herein to the "inking rollers" is to be construed broadly to 
cover any roller applying ink to the surface of a plate on the plate 
cylinder, and may for example denote the ink distributing oscillating 
roller of the inking unit.