Deviator device for webs, particularly paper webs

Deviator device for a web, particularly a paper web, in which a deviator drum, disposed between an inlet guide surface and an outlet guide surface for the web, is variously inclined by rotation about an axis tangential both to the inlet surface and to the drum, in order to move the web transversely to the inlet surface through a required distance which can be varied at will within a required range.

BACKGROUND OF THE INVENTION 
The present invention relates to a deviator device for webs, particularly 
paper webs. 
In machines of any type which use continuous webs of paper or other like 
material, such as wrapping machines and packaging machines of any type, it 
is often necessary to transversely deviate a web in order to avoid some 
device on the machine, or in order to bring the web into perfect alignment 
with a web utilisation device disposed offset from the web. 
In order to transversely deviate a web while keeping it parallel to itself, 
it is known to use a bar which can be variously inclined parallel to the 
feed plane of the web, and about which the web is wound in a spiral. 
Such a known device, described for example in British Pat. No. 957,740, 
cannot be used if the web is particularly thin and delicate, and its feed 
speed exceeds a relatively low determined value. 
In this respect, because of the friction forces which develop in contact 
with the deviator bar, the web tends to grip on to this latter, and if 
fragile is torn as soon as the speed becomes appreciable. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide a deviator device which 
is free from the aforesaid drawbacks and is of simple construction and 
easy use. 
The said object is attained according to the present invention by a 
deviator device for webs, particularly paper webs and the like, comprising 
an inlet guide surface and an outlet guide surface for said web; a 
deviator drum mounted rotatable about a first axis and disposed between 
said inlet and outlet surfaces, said web winding in contact with part of 
the periphery of said drum when in use; and adjustable support means for 
varying the position of said first axis about a second axis perpendicular 
to the first and tangential both to said drum and to said inlet surface.

DETAILED DESCRIPTION OF THE INVENTION 
FIG. 1 shows a deviator device indicated overall by 1, to which there is 
fed a continuous web 2, in particular a thin paper web, of which the 
outlet direction from the device 1, indicated in FIG. 1 by an arrow 3, is 
displaced transversely to the inlet direction of the web 2 in the device 
1, indicated by an arrow 4 in FIG. 1, by a distance A which can be varied 
at will within a determined range. 
The device 1 comprises a fixed support plate 5, to which a web guide unit 
indicated overall by 6 and a web deviation unit indicated overall by 7 are 
connected in positions facing each other. 
The web guide unit 6 comprises a support plate 8 connected to the plate 5 
by connection means, not shown. Preferably, but not necessarily, these 
connection means are of the detachable type and are arranged to enable the 
plate 8 to be positioned at will along a longitudinal axis of the plate 5. 
Three pins 9, 10 and 11 extend from the plate 8 on the opposite side to the 
plate 5 and perpendicular thereto, they being preferably disposed in the 
same plane as in the example illustrated, and the first two being close 
together and disposed at a certain distance from the third, the pin 10 
being disposed in a position between the pins 9 and 11. 
Respective cylindrical rollers 12, 13 and 14 having a length greater than 
the width of the web 2 are rotatably mounted on the pins 9, 10 and 11 by 
way of bearings, not shown. 
The pins 9 and 10 are mounted in a fixed position on the plate 8, and the 
pin 11 could also be connected in a fixed position on the plate 8, but is 
preferably mounted thereon by way of adjustment means in order to be able 
to traverse transversely to its own axis parallel to the plane of the pins 
9 and 10. 
For this purpose, as shown in particular in FIG. 2, the plate 8 comprises, 
on the side facing the roller 14, a groove 15 having its axis parallel to 
the plane of the pins 9 and 10 and in the base surface of which there is 
provided a through slot 16 traversed by the pin 11. This latter is 
provided with an elongated flange 17 which slidably engages the groove 15, 
and has a threaded end emerging from the slot 16 and engaged by a nut 18, 
by tightening which it is possible to lock the flange 17 in any position 
along the groove 15. 
The web deviation unit 7 comprises a substantially parallelepiped block 19 
welded to the plate 5 in a position adjacent to the plate 8, and having a 
rear surface 20 disposed in contact with the plate 5, a side surface 21 
perpendicular to the plate 5 and parallel to the plane of the pins 9 and 
10, and a front surface comprising a surface 22 parallel to the plate 5 
and an inclined surface 23 connected together by a flat shoulder 24 
perpendicular to the surfaces 21 and 22. 
On the surface 21 there is provided a groove 25 in the form of a circular 
arc, its ends being open and disposed one at the other end of the surface 
22 to the shoulder 24, and the other on the centre line of the surface 23. 
A slide 26 in the form of a circular sector having a curvature identical to 
that of the groove 25 and with a length greater than that of this latter 
is slidably mounted in the groove 25. 
The slide 26 has a substantially square cross-section, and is provided with 
two curved slots 27, through each of which there extends a respective 
screw 28 provided with a washer 29 and arranged to lock the slide 26 in 
the groove 25 in any required position. 
One of the ends of the slide 26 extends outside the surface 23, and rigidly 
carries a pin 30, of which the axis T (FIG. 2) is substantially tangential 
to the longitudinal axis of the slide 26. The pin 30 rotatably supports a 
cylindrical drum indicated overall by 31 and comprising an outer 
cylindrical wall 32 provided at one end with an annular flange 33, which 
extends outwards from the centre line of a tubular hub 34 coaxial to the 
wall 32 and is rotatably coupled to the pin 30 by way of two bearings 35. 
From FIG. 2, which is constructed by projecting the device 1 on to a plane 
parallel to the surface 21, it can be seen that the adjustable support 
means for said drum 31, i.e. the groove 25 and slide 26, have an axis of 
which the trace in the plane of FIG. 2 is indicated by H, this being 
perpendicular to the axis T and tangential both to the generating line of 
the roller 13 which faces the roller 14, and to a point on the centre of 
the generating line of the outer surface of the wall 32 facing the roller 
13. This positional relationship is maintained whatever the position of 
the slide 26 along the groove 25, as the axis H is the axis about which 
the system constituted by the slide 26 and drum 31 rotates. When in 
operation, if a length of the axis 36 of the web 2 extending along a 
portion 37 of the web 2 leaving the device 1 is to be displaced 
transversely through a predetermined distance A with respect to a length 
of the axis 36 of the web 2 extending along a portion 38 of the web 2 
entering the device 1, the slide 26 is positioned along the groove 25 such 
that the axis T of the drum 31 forms an angle a with a straight line 
parallel to the axes of the pins 9 and 10, so that: 
EQU A=D sin a 
where D is the diameter of the drum 31, i.e. the diameter of the outer 
surface of the wall 32. 
The roller 14 is then displaced transversely until that generating line 
thereof facing the roller 13 is tangential to an axis K (FIG. 2) parallel 
to the axis H and tangential to a centre point on the generating line of 
the outer surface of the wall 32 facing the roller 14. 
Finally, the web 2 is wound manually first about the roller 12 (in the 
anticlockwise direction in FIG. 1), then about the roller 13 (in the 
clockwise direction in FIG. 1), then about the drum 31 (in the 
anticlockwise direction in FIG. 1) and then about the roller 14 (in the 
clockwise direction in FIG. 1) in the direction indicated by the arrows 4 
and 3. 
The outlet portion 37 of the web 2 is then connected to a traction device 
(not shown), which when operated causes the web 2 to rapidly unwind 
through the device 1. 
The position occupied by the web 2 and illustrated, in particular, in FIG. 
1, in which the axis 36 of the web 2 extends along the axes H and K, is 
the most favourable in that it minimises the forces applied to the web 2 
during its transverse movement. In this respect, in this position, the 
central zone of the lengths of web 2 extending between the drum 31 and the 
rollers 13 and 14 is subjected to pure torsion and to the traction 
imparted by the said traction device. 
From the aforegoing, it is possible to use the device 1 even if extremely 
thin and delicate webs 2 are used. 
As the position of the web 2 shown in FIGS. 1 and 2 is a position of 
"minimum force", i.e. a position of stable equilibrium, it also follows 
that the positioning of the web 2 about the rollers 12, 13 and 14 and the 
drum 31 does not require any particular care. In this respect, even if 
positioned in an incorrect manner, the web 2 becomes immediately disposed 
in the position illustrated in FIGS. 1 and 2 as soon as the traction 
device (not shown) is started, with the result that, when in use, the 
lateral displacement of the portion 37 relative to the portion 38 is 
always exactly equal to the required displacement A. 
With regard to the roller 12, it should be noted that it is necessary only 
when the arrows 3 and 4 point in the same direction, whereas it can be 
dispensed with or otherwise not utilised if the arrows 3 and 4 point in 
opposite directions. 
FIG. 3 shows a deviator device indicated overall by 39, the component parts 
of which are substantially identical to those of the device 1 and are 
indicated by the same reference numerals. The device 39 is also 
conceptually identical to the device 1, from which it differs only in that 
its roller 14 is disposed to the side of the rollers 12 and 13, and the 
drum 31 is disposed to the side of the rollers 12 and 13 and substantially 
aligned vertically with the roller 14. The different arrangement of the 
web 2 about the rollers 12, 13 and 14 and drum 31 can be perfectly deduced 
from the position of the web 2 shown in FIGS. 1 and 2, and does not 
require further explanation. 
Within the principle of the invention, numerous modifications can be made 
to the described deviator devices without leaving the scope of the 
inventive idea. 
In particular, the rollers 13 and 14 could be replaced by curved plates 
(not shown) arranged to define an inlet guide surface and an outlet guide 
surface in sliding cooperation with the web 2.