Note: Descriptions are shown in the official language in which they were submitted.
CA 02558863 2006-09-06
APPARATUS AND METHOD FOR THE TRANSPORT OF WEB-LIKE
MATERIAL
BACKGROUND
The invention relates to an apparatus and method for the
transport of web-like material, in particular printed webs or packets of
printed webs fed from a fold former positioned downstream of a printing
machine with a roll that can be driven and against which pressure-
application rolls can be adjustably pressed.
The pressure-application rolls, together with the driven draw-
rolls, form an in-draw gap. It is necessary, therefore, to take measures to
effectively prevent the risk of fingers being crushed. In the known
arrangements a protective hood is provided for the pressure-application
rollers. This certainly offers adequate protection against the risk of fingers
being crushed. It is a disadvantage, however, that the protective hood
prevents a clear view being obtained of the in-draw gap and of the
transported web material. A quite special disadvantage is that the space
between a protective hood and a pressure-application roll can become
smaller which leads to the pressure-application roller being blocked.
Experience has shown that when webs of paper are being processed so-
called spaghetti-formation often develops as a consequence of the faulty
adjustment of slitting knives, etc., in that the spaghetti collects between
one
or more protective hoods and the associated pressure-application rolls and
blocks them after a period of time. This results in the affected pressure-
application rolls grinding on the driven draw-rolls which leads to the
flattening and, consequently, to the destruction of the pressure-application
rolls.
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SUMMARY
It is therefore the object of the present invention to improve an
arrangement of the type described above with simple and economic means
such that the use of a protective hood can be dispensed with while
nevertheless providing adequate protection against the risk of fingers being
crushed.
This objective is achieved according to the invention in that the
pressure-application rolls are carried by a relevant assigned position-
setting assembly which exhibits at least one actuating element capable of
receiving an impulse from a pressure-applying agent, where the impulse
from the pressure-applying agent can be controlled according to a pre-
settable timing sequence by a control device.
These measures offer the possibility in an advantageous manner
that the position-setting procedure does not have to operate suddenly as
before but rather that it can proceed comparatively slowly and/or in several
stages. This ensures that that an operator, who when adjusting the setting
of the pressure-application rolls - an activity which in many cases requires
direct vision of the relevant pressure-application roll - must insert his/her
fingers into the danger area to detect the adjustment movement of the
pressure-application roll, has sufficient time to withdraw his/her fingers
before the position-setting procedure is completed or the full application of
pressure takes effect. It is possible, therefore, advantageously to dispense
with all other protective measures. Also advantageously, there is
consequently no longer any danger that a pressure-application roll can be
blocked in the event of spaghetti build-up and destroyed as a result. In
addition to providing a high level of working safety, the measures according
to the invention accordingly guarantee a high level of process security and
freedom from the risk of breakdown which has a beneficial effect upon the
overall economic situation.
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Thus, the control device can expediently exhibit a control valve
which is designed as a proportioning valve and arranged in a supply line
which provides a pressure-applying agent and is assigned to the position-
setting assembly. With the assistance of a proportioning valve it is possible
to achieve in an advantageous manner not only any desired timing
sequence but also any desired final level of applied pressure - and to do so
in a simple way.
A further extension of the present invention is that the control
valve can be controlled by a memory-endowed computer in which the
desired timing sequence together with, preferably, the desired level of
applied pressure is stored. This ensures an automatic implementation of
the position-setting procedure. A further advantage is that in the event of a
change in the desired timing sequence, etc., only the relevant software
needs to be amended. It is therefore possible to adapt to the circumstances
of the individual situation in a simple manner.
In a further extension of the present invention, the position-
setting assembly can exhibit a housing block with two projectable pistons
where each one seals off a working space which can receive an impulse from
a pressure-applying agent and where the ends protruding out of the
housing block are connected by a yoke upon which is securely mounted at
least one appropriate axle carrying at least one pressure-application roll.
The twin pistons provided here with the yoke carrying the axle provide a
high degree of stability and consequently very smooth running of the
pressure-application roller. In addition, the integration of the cylinder-
piston frame in a housing block results in a very compact arrangement.
A further expedient advantage can be that at least one return
positioning spring in the housing block is assigned to the yoke.
Consequently, the pistons can be designed as simple operating pistons
which permits a simple form of construction.
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Further advantageous developments and expedient extensions of
the overriding measures of the present invention are provided in greater
detail in the example description below and by reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
Figure 1 shows a partial view of the upper part of a folding section
with a fold former and an associated in-draw arrangement;
Figure 2 shows a pressure-application roll with an associated
position-setting assembly in the fully engaged position;
Figure 3 shows the arrangement according to Figure 2 in the
disengaged position;
Figure 4 shows an applied pressure/time diagram; and
Figure 5 shows a view of a pressure-application roller arranged so
as to be laterally displaceable.
DETAILED DESCRIPTION OF THE DRAWINGS
Figure 1 illustrates a fold former 2 arranged in the upper part 1 of
a folding section to which a web packet consisting of several webs imposed
upon one another is directed and which come from an upstream printing
machine not shown in any greater detail here. For this purpose, the
individual webs leaving the printing machine run over a so-called harp
consisting of several in-feed rolls 3, the deflection rolls 4 and the in-draw
devices 5 arranged successively. Each of the in-draw devices 5 consists of a
draw-roll 7 extending the full width of the machine and powered by an
assigned drive motor 6 where adjustable pressure-application rolls (trolleys)
8 can be pushed against the draw-roll. The pressure-application rolls 8 are
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mounted on freely rotating bearings and rotate solely under the influence of
friction.
The pressure-application rolls 8 can be positioned against or away
from the relevant assigned draw-roll 7. All the pressure-application rolls 8
or selected pressure-application rolls may be involved. To serve this
purpose, the pressure-application rolls 8 are mounted in a position-setting
assembly 9 which permits the pressure-application roll 8 to move at right
angles to its axis. As can be seen from Figures 2 and 3 each position-setting
assembly 9 contains a housing block 10 with an integrated cylinder-piston
arrangement to effect the desired adjustment of the assigned pressure-
application roll 8. To that end, the housing block 10 is provided with two
bored holes which run in the engaged and disengaged position-setting
direction. These holes are closed at the rear by a fitting 11 and each of
them is penetrated internally by a length of shaft functioning as a piston 12
which together with the fitting 11 demarcates a working space 14 which
can be dynamically filled through a supply line 13 by a pressure medium,
preferably compressed air. The ends of the pistons 12 remote from the
working space 14 protrude out of the housing block 10 and they are
connected to one another by a yoke 15 forming a portal-like configuration
which guarantees high stability. A protruding axle 16 is secured to the
yoke 15 on which the relevant assigned pressure-application roll 8 is
mounted in a manner permitting free rotation. The axle 16 is flattened
where it sits on the yoke 15 to provide plane contact surfaces.
The pistons 12 are designed as simple working pistons which
when pressure is applied to the relevant assigned working space 14 are
pushed away from the basic driven-in position illustrated in Figure 3 to the
basic driven-out position illustrated in Figure 2. The reverse motion is
effected by a return positioning spring 17. To facilitate this the housing
block 10 is provided with a central bored hole 18 into which a pin 19
attached to the yoke 15 penetrates. The yoke side of the bored hole 18 is
closed by a fitting 20 which is pierced by the pin 19. The side of the pin 19
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that is remote from the yoke is provided with a spring plate 21. The return
spring 17 is supported on one side by the fitting 20 and on the other side by
the spring plate 21. In the course of the position-setting procedure, i.e.,
when driving out the pistons 12, the return positioning spring 17 is
compressed. As soon as the pressure in the working spaces 14 drops, the
return positioning spring 17 pushes back the yoke 15 and the pressure-
application roll 8 carried upon it from the basic engaged position shown in
Figure 2 to the basic disengaged position shown in Figure 3 in which the
pistons 12 are driven up to the stop on the rear-mounted fittings 11 in the
housing block 10.
In order to prevent any risk of fingers being crushed, the position-
setting movement of the pressure-application rolls 8 does not take place
suddenly, but rather, slowly and or in several stages with increasing speed.
To that end, as depicted in Figure 2, a control valve 22 is arranged in the
common supply line 13 from a source of pressure which is not illustrated in
any more detail to the two working spaces 14 in the housing block 10.
Expediently, this valve is designed as a proportioning valve and by its use
the generation of pressure in the working spaces 14 can be controlled such
that a desired timing sequence is obtained for the generation of pressure in
the working spaces and, consequently, of the setting and application of
pressure upon the pressure-application rolls 8. A control device 23 is
provided to activate the control valve 22, which control device expediently
contains a computer into the memory of which the desired timing sequence
can be stored.
As mentioned above, the generation of pressure in the working
spaces 14 and, correspondingly, the execution of the position-setting
procedure can proceed slowly or in several stages. A multistage position-
setting and pressure-application procedure is illustrated in Figure 4. The
function 24 depicted schematically in Figure 4 schematically shows the
course of the level of applied pressure with time.
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In a first stage here, the pressure-application roll 8 is placed
against the assigned draw-roll 7 with no or negligible force. In a second
stage there is a progressive increase in the level of applied pressure up to a
desired norm value which develops in a linear or slow manner. It is
expedient if in the first stage the level of applied pressure is only slightly
higher than the return force exerted by the return positioning spring 17.
The selected norm value for the second stage, i.e., the final application
pressure, can also be stored in the memory of the computer. In the case of
different product situations, e.g., wide format or tabloid format, different
norm values can be stored so that the norm value can also vary.
The first stage can be started by a switching procedure where the
pressure rises comparatively quickly to the abovementioned strength of the
return positioning spring 17, which is indicated by the stage "s". Continued
switching from the first to the second stage can result from a time-function
element in the control device 23 which is initiated at the beginning of the
first stage and continues the switching procedure at the end of the second
stage. It is also conceivable to arrange for the further switching procedure
from the first to the second stage to be dependent upon the operating
circumstances of the printing machine, for example, the instant of the first
instruction to run, i.e., the commencement of printing. To achieve this, the
control device 23 can be connected to the control system of the printing
machine as is indicated by an input 25. To facilitate a manual start the
control device is provided with an input 2'7 connected to a switch 26. The
first stage can also be started by this means. It is also conceivable to start
the first stage automatically in dependence upon the operating
circumstances of the printing machine, for example at the completion of the
feed-through operation.
Once the second stage has commenced, the pressure rises
comparatively slowly along the ramp "r" to the abovementioned norm value.
In the illustrated example the ramp r is linear. A non-linear or stepped rise
is, however, also conceivable.
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The pressure-application rolls 8 are positioned only in the
pressure-free areas of the relevant web in motion. Correspondingly, the
pressure-application rolls 8 can be arranged to be adjustable over the width
of the machine. To that end and as can be seen from Figures 1 and 5, each
position-setting assembly 9 which carries a pressure-application roll 8 is
provided with a carriage 28 which accepts the appropriate housing block 10
and which is displaceably mounted on a traverse 29 extending across the
width of the machine. The position of the carriages 28 can be changed
either manually or by powered means, for example by a motor-driven
threaded shaft, and then locked in the desired position. This is effected by
a clamping device which is shown in Figure 5 only by its activation lever 30.
In the illustrated example the clamping device for locking the
relevant assigned carriage 28 is operated manually by the activation lever
30. In the case of motorized adjustment of the position of the carriage 28 it
is also possible to provide mechanically operated locking by, for example, an
electromagnetic device.
List of reference symbols:
1 Upper part of a folding section
2 Fold former
3 In-feed rolls
4 Deflection rolls
In-draw devices
6 Drive motor
7 Draw-roll
8 Pressure-application rolls
9 Position-setting assembly
Housing block
11 Fitting
12 Piston
13 Supply line
14 Working space
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15 Yoke
16 Axle
17 Return positioning
spring
18 Bored hole
19 Pin
20 Fitting
21 Spring plate
22 Control valve
23 Control device
24 Ramp function
25 Input
26 Switch
27 Input
28 Carriage
29 Traverse
30 Activation lever
The foregoing disclosure has been set forth merely to illustrate
the invention and is not intended to be limiting. Since modifications of the
disclosed embodiments incorporating the spirit and substance of the
invention may occur to persons skilled in the art, the invention should be
construed to include everything within the scope of the appended claims
and equivalents thereof.
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