Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DEVICE AND METHOD FOR DETECTING AND COUNTING
ARTICLES, RELEASED BY A FEEDER DEVICE, IN PARTICULAR
SHEET ARTICLES RELEASED BY A SHEET FEEDER
TECHNfCAt. FIELD OF THE INVENTION
The present invention relates to the technical field of packaging
machines of piles of sheet articles, for example of paper documents,
inserts or the like, which piles, when packaged, are intended 'to be sent
by post; in particular, the invention relates to devices for detecting and
counting the sheet articles released by feeder'devicesincluded in~the
sarrie packaging machines.
DESCRIPTION OF THE ART
A known packaging machine of the above-described type comprises: a
conveyor member, which, by means 'of shaped strikers; `spaced at- a
predetermined distance, moves con-esponding article piles forming in
an advancement direction; a first feeder device 'arranged upstream of
the conveyor member, which above the latfier; intermitfently releases a
sheet article at the time (that is a magazine, a bundfe or the' like)
intended to be intercepted by a corresponding shaped striker; a plurality
of feeder devices arranged in cascade along the development of the
conveyor member to release, in suitable phase relation and above the
latter, respective sheet articles (sheet articles, as for example paper
inserts or the like) in order to progressively form piles in advancement;
and a station, arranged downstream of the conveyor member, for
packaging the thus formed piles, for exampie for their introduction in
envelopes or their winding by means of a film or sheet, of plastic or
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paper respectively.
According to a diffused structural configuration, a feeder device
comprises two endless belt conveyors, mutually arranged to provide as
many active counter-faced branches, a lower and an upper one,
intended to drag gripped sheet articles towards an output section
communicating with said conveyor member, in particular the upper
conveyor has the driven gear, defined by a much greater dimensioned
drum than that of the remaining driving gears, driven gears and snub
pulleys and is provided with suction means intended -to take an article
at the time from the base of a thereon arranged pile, which is integral to
the frame of the feeder, according to known ways, and to drag. the
article until the two counter-faced branches, which extend partially
around"a section of the lower profile of the same drurn; griFiA:
Such feeder device is associated with means, which:--interact -with,.-a
determined lower portion of such counter-faced- branches, which, is : in
contact with the drum, these means being intended .;to detect the
passage of none, one or more superimposed sheet. articles;: -.their
control function being aimed at the generation of an error signalõin case
instead of a single sheet article, no sheet article passes or_two or,more
superimposed sheet articles pass. Usually, these control. means
comprise: a mechanic amplifier, which interacts with said belt portion,of
the lower conveyor, intended to induce a rotation of one. detecting, arm
of its own, proportionally to the shifting undergone ~ by the same belt
portion; after the passage of one or mom sheet articl"'es; a proximity
sensor, sighting a direction perpendicular to the area interested* by the
same arm and interfering with the latter. The -rnechanic'amplifier can,be
for example a shaft, rotatably carried on the frame of the feeder device,
constrained on one side at a transversal detecting arrn and onAhe other
one at a little arm, which on the opposing end, comprises an idle roller
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(so-calied "feeler"), which rails on said belt portion of the lower
conveyor and is in contact thereon by means of elastic means,
interposed between the same little arm and the frame. Therefore,
following the passage of a sheet article above the belt portion
intercepted by the roller, the detecting arm carries out a temporary
rotation from a stable rest position to a first angular position, carrying
out an excursion as much marked as greater the thickness of the
passing article is; when the passage is ended, the detecting arm comes
back to its original, stable balancing position.
The sensor is disposed such that its optic beam sights the detecting
arm when the latter is stable in the first angular position, in order to
break the light beam, for a minimum predetermined time, only when a
sheet article passes. A local computer unit, fo.r example associated to
the feeder device, receives the signals supplied by the proximity
sensor; by way of example it can define an error state, to which the
production stop might follow, if, when a sheet article is required to the
output of the feeder, the relative signal generated by the proximity
sensor, indicating the passage of a single sheet article in a determined
time, does not correspond. A similar solution is very diffused in this
field, even if it implies many drawbacks: sheet articles of relevant
thickness (therefore, for example more than sixty micrometers), in fact,
determine remarkable mechanic stresses on the mechanic amplifier,
defining an upper limit of the operative speed of the feeder and
therefore of the productivity of the packaging machine in which the
latter is integrated; moreover, such limit, has to be further reduced to
allow the same amplifier to withstand stress "peaks", which are induced
by the undesired passage of two or more superimposed sheet articies
between the counter-faced branches. The position of the sensor
emitted light beam has also to be adjusted every time a format change
of the loaded articles in the feeder device is required, as a thickness
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variation of the passing article between the counter-faced branches
corresponds to a different angular excursion of the detecting arm;
clearly, this operation requires expert personnel, a great number of
technical tests, suitable devices and a remarkable time in comparison
to the pressing requirements of a productivity, which is higher and
higher. Moreover, the required adjusting times increase according to
the total number of feeder devices associated to the conveyor member
(being not possible the usage of an operator and the required
equipment for every conveyor, for obvious cost reasons), and become
therefore unsustainable as the packaging machine becomes more
complex.
Generally, it can be said that the devices for detecting and counting
sheet articles released by feeder devices are disadvantageous because
they are subjected to detecting errors and because they define, in order
to properly function, a significant limit to the productivity of the
packaging machine.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a device for
detecting and counting sheet articles, intermittently. released by a
feeder device, which is able to satisfactorily solve the above-mentioned
drawbacks, peculiar to the known solutions; so it is, intended to provide
a newly designed device, which is reliable, precise, functional, compact
and which can be easily integrated inside feeder devices of known type
as well, and whose costs are relatively reduced with respect to the
advantages, which it is intended to pursue.
Another object of the present invention is to provide a method for
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detecting and counting sheet articles, intermittently released by a
feeder device which is able to satisfactorily solve the above-mentioned
drawbacks, peculiar to the known solutions; so it is intended to provide
a newly designed method, distinguished by an essential number of
operating steps, which allows to precisely and reliably detect and count
the sheet articles released by a feeder device and whose
implementation costs are relatively reduced with respect to the
advantages, which it is intended to pursue.
Said above-mentioned objects are accomplished by a device and a
method according to claims 1 and 7, respectively.
The device for detecting and counting sheet articles released by 'a
feeder device, in particular sheet articles released by a sheet feeder, is
characterized in that it cornprises: an electromagnetic resonator fed by
a first signal supplied by a signal generator, to generate an
electromagnetic field in a passage region of said sheet articles; a
sensor connected to the output of said electromagnetic resonator for
detecting a second signal which identifies the induced disturbances in
said electromagnetic field following -the passage of said one sheet
article or the passage of a piurality of said superimposed,sheet articles;
and a control unit connected* to said sensor for calculating the number
of said sheet articles, which pass from time to time across said passage
region.
In a dependent claim, it is precised that the electromagnetic resonator
is a resonator of recess type, in which it is made an aperture which
makes this recess communicating with the outside and that said
electromagnetic resonator is arranged such that said aperture is
disposed at said passage region of said sheet articles.
The method for detecting and counting articles released by a feeder
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device, in particular sheet articles released by a sheet feeder, is
characterized in that it comprises the following operating steps:
intermittently releasing sheet articles by said feeder device; conveying
said sheet articles, thus released, across a passage region in which a
predetermined electromagnetic field acts; detecting the disturbances
induced in said electromagnetic field after the passage of said one
sheet article or after the passage of a plurality of said superimposed
sheet articles; calculating the number of said- sheet articles, which pass
from time to time across said passage region according to the
measurements carried out in the preceding step.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the invention, not emerging from the preceding
description, will be better highlighted in the follovi+ing, according to the
claims and by means of the appended drawings, in which:
- figure 1 shows a side schematic view of a feeder device of known
type, in which the inventive device for detectirig and counting sheet
articles is integrated;
- figure 2 shows a functional scheme of the device for detecting and
counting of figure 1;
- figure 3A shows the recess electromagnetic resonator shown in figure
1, while figure 3B shows a variant thereof;
- figure 4A shows an illustrative graph of the amplitude according to the
frequency of a signal emitted by the electromagnetic resonator, the
graph representing three curves, relative to as many functioning
configurations indicated by #0, #1, #2 (no sheet article passing, one
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sheet article passing, two superimposed sheet articles passing;
respectively);
- figure 4B shows an illustrative graph of the phase displacement
according to the frequency of a signal emitted by the electromagnetic
resonator, the graph representing three curves, relative to as many
significant functioning configurations indicated by #0, #1, #2 (no sheet
article passing, one sheet article passing, two superimposed sheet
articles passing; respectively).
DESCRIPTION OF PREFERRED EMBODIMENTS
In figure 1, by the reference number 10 is indicated in its entirety a
feeder device of known type, substantially of the above-described type,
in which the inventive device 100 for detecting and counting sheet
articles is integrated.
The shown feeder device 10 comprises two endless belt conveyors 1,
2, mutually arranged to 'provide as many active counter-faced
branches, a lower one 21 and an upper one 22, intended to drag
gripped sheet -articles 3 towards an output section U communicating
with said conveyor member (not shown) of the packaging machine
(also not shown as not relevant to the invention); in particular, the upper
conveyor 1 has the driven gear, defined by a much greater
dimensioned drum 4 than that of the remaining driving gears, driven
gears and snub pulleys and is provided for example with gripping
means (not shown) intended to take an article 3 at the time from the
base of a thereon arranged pile 5, which is integral to the frame 6 of the
feeder 10, according to known ways, and to drag the article until the
two counter-faced branches 21, 22, which extend partially around a
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section of the lower profile of the same drum 4, grip it.
The inventive detecting and counting device 100 is functionally
disposed at a section of the path, which is run by each sheet article 3
released from the pile 5 and moved towards the output section U,-
according to ways, which will be better described in the following; in the
example shown in figure 1, the device 100 is fixed at the frame 6 and
arranged upstream of the counter-faced branches 21, 22 of the two belt
conveyor 1, 2.
The detecting and counting 'device 100 comprises an electromagnetic
resonator 11 of recess type, in which it is made an apertui-e 7, which
makes the same recess 8 communicating with the outside; the
electromagnetic resonator 11 is so positioned that the aperture 7 is
arranged at a region 9 which is provided immediately upstream of the
counter-faced branches 21, 22 and in which the sheet.articles 3,
conveyed towards the output section U of the feeder 10 are destined to
pass. In.general, however, the electromagnetic resonator 11 can be
arranged in any section of the path run by the sheet articles 3 released
from the pile 5 and conveyed towards the output section U of the feeder
10; as a particular case, the resonator 11 can be functionally interposed
betweeh the output section U and the conveyor member of the
packaging machine, that is to say, outside the feeder 10.
The inventive device 100 comprises also: a signal generator 12 which
supplies the electromagnetic resonator 11 with a signal S1 to define an
electromagnetic field in the recess 8 and in the aperture 7 coinciding
with the passage region 9; a sensor 13 connected to the output of said
electromagnetic resonator 11 to detect a signal S2 which identifies the
induced disturbances in the electromagnetic field following the passage
in the passage region 9 of a sheet article 3 or of a plurality of
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superimposed sheet articles 3; an analogue-to-digital converter 15 for
converting in digital format the analogue signal supplied by the sensor
13; and a control unit 14 connected to the signal generator 12 and to
the analogue-to-digital converter 15, which controls the functioning of
the detecting and counting device 100 in its entirety and which is
connected to other not shown outer units, for example a control panel
for the operator and/or electromechanical apparatuses of the packaging
machine.
The signal generator 12 comprises for example oscillating electronic
circuits and/or numerical control circuits DDS (Direct Digital
Synthesizer) and supplies the high frequency signal S1 having a
frequency between 1 MHz and 100 GHz, at the input of the
electromagnetic resonator 11.
By way of example, the sensor 13 is instead a detector device, which
converts the high frequency signal S2 received by the electromagnetic
resonator 11 in two signals in direct current (DC), whose values vary
according to the amplitude (power) and to the phase of the same signal
S2. In the appended drawings, various illustrative embodiments of the
recess electromagnetic resonator 11 are shown; in figures 1, 3B the
electromagnetic resonator 11 extends in longitudinal direction, has a
rectangular transversal section, and the aperture 7 is made according
to the relative longitudinal development dividing the same resonator 11
in two distinct and counter-faced portions 16, 17; figure 3A shows
another example of the electromagnetic resonator 11, with a cylindrical
configuration, also distinguished by the aperture 7 made according to
the longitudinal development dividing the same resonator 11 in two
distinct and counter-faced portions 16, 17; in the schematic
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representation of figure 2, the electromagnetic resonator 11 in instead
similar to the one represented in figures 1, 3B but it is different in that it
is an unique body with the aperture 7 of predetermined depth. The
recess 8 of the electromagnetic resonator 11 can be for example
interested by air or Teflon.
The functioning of the inventive detecting and counting device 100 is
based on detecting the disturbance of the electromagnetic field acting
in the aperture 7, which as said, thanks to the suitable arrangement of
the recess electromagnetic resonator 11, coincides with the passage
region 9 of the sheet articles 3. Such disturbance of the
electromagnetic field is caused by the passage of a sheet article 3
across the passage region 9 or of more superimposed sheet articles 3
which, by mistake, have been drawn from the base of the pile 5 of the
feeder 10.
Therefore, the aperture 7 is so shaped and dimensioned to allow the
passage of one or more superimposed sheet articles 3 and to define a
predetermined electromagnetic field in order to detect the passage of
said sheet articles 3.
The functioning of the inventive detecting and counting device 100
results generally from the following description of the method for
detecting and counting sheet articles 3, intermittently released by the
feeder device 10, also object of the invention, the method comprising
the following operating steps:
a. intermittently releasing sheet articles 3 from the pile 5 of the feeder
device 10;
b. conveying the sheet articles 3 across the passage region 9 in which
a predetermined electromagnetic field defined by the signal generator
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12 acts;
c. detecting the disturbances induced in this electromagnetic field after
the passage of said one sheet article 3 or after the passage of a
plurality of superimposed sheet articles 3;
d. calculating the number of sheet articles 3, which pass from time to
time across the passage region 9 according to the measurements
carried oa in the preceding step.
In the following, it will be described in further detail one among the
possible functioning ways of the detecting and counting device 100,
object of the present invention.
Figure 4A shows an illustrative graph of the amplitude variation of the
signal S2 according to the frequency, when at the input of the
electromagnetic resonator 11 is applied a signal S1 of prefixed
ampiitude and phase:.the graph shows three curves indicated by #0,
#1, #2, which represent-the different behaviour of the electromagnetic
resonator 11 in case in the passage region 9 no sheet article 3 passes
(curve #0), 'only one sheet article 3 passes (curve #1) 'or two
superimposed sheet articles 3 pass (curve #2). As it can be noted,
these curves run in a "bell-like" way, which is peculiar to an
electromagnetic resonator, which "resounds" at the frequency
(resonance frequency), centred with respect to the corresponding
reference curve.
Figure 4B allows similar considerations. It shows an illustrative graph of
the phase variation of the signal S2 according to the frequency when at
the input of the electromagnetic resonator 11 is applied a signal $1 of
prefixed amplitude and phase; in fact, the graph shows three curves
indicated by #0, #1, #2, which represent the different behaviour of the
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electro magnetic resonator 11 in case in the passage region 9 no sheet
article 3 passes (curve #0), only one sheet article 3 passes (curve #1)
or two superimposed sheet articles 3 pass (curve #2).
Fo indicates the resonance frequency of the "Ioadiessn electromagnetic
resonator (no sheet article 3, curve #0); the praxis suggests to choose
the frequency F5 of the signal S1 preferably between Fo-5*FolQo and
Fo+5*Fo/Qo, where Qo is the merit factor of the electromagnetic
resonator 11 when in the. passage region 9 there is. no sheet article 3
passing.
The graphs shown in figures 4A, 4B define: Ao(Fs), PQ(FS) respectively
as amplitude and phase of the signal S2 when there are no sheet
articles 3 in the passage region 9; A,(Fs), P,(FS) as amplitude and
phase of the signal S2 when there is only one sheet article 3 in the
passage region 9; AZ(FS), P2(Fs) as amplitude and phase of the signal
S2 when there are two sheet articles 3 in the passage region 9.
It is possible to define the attenuation and the phase displacement
undergone by the signal S2 when only a single sheet article 3 passes in
the passage region 9, as:
dAI(Fs)= IAo(Fs) - A,(Fs)I
AP1(Fs)= JPo(Fs) - P,(Fs)j
and the attenuation and the phase displacement undergone by the
signal S2 when two superimposed sheet articles 3 pass in the passage
region 9, as:
AAz(Fs)= lAo(Fs) - A2(Fs)l
b,Ps(Fs)= IPo(Fs) - P2(Fs)I
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In general terms, the attenuation and the phase displacement
undergone by the signal S2 can be instead defined as:
AAI-(Fs)= lAo(Fs) - AL(Fs)l
APL(Fs)= IPo(Fs) - PL(Fs)I
where AL(Fs), PL(FS) are respectively the amplitude and the phase of
the signal S2 detected at the frequency FS after the passage of zero,
one, two or more superimposed sheet articles 3 in the passage region
9.
When the attenuation AAi(Fs), AA2(Fs) undergone by the signal S2, in
case of passage of one sheet article 3 or of two superimposed sheet
articles 3 respectively in the passage region 9, is known, it is possible
to provide suitable threshold values TAL, TAH with TAL<TAH so that:
- if AAL(Fs) is greater than the lower threshold TAL and smaller than the
upper threshold TAH, there is a sheet article 3 in the passage region 9;
- if QAL(FS) is smaller than the lower threshold TAL there are no sheet
articles 3 in the passage region 9;
- if AAL(Fs) is greater than the upper threshold TAH, there are at least
two superimposed sheet articies 3 in the passage region 9, whereby a
drawing error of the sheet articles 3 from the base of the pile 5 is
detectable.
Similarly, when the phase displacement AP2(Fs), API(FS) undergone by
the signal S2, in case of passage of one sheet article 3 or of two
superimposed sheet articles 3 respectively in the passage region 9, is
known, it is possible to provide suitable threshold values TPL, TPH with
TPL<TPH so that:
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- if APL(FS) is greqter than the lower threshol.d., TP~ and smaller than the
upper threshold TPH, there is a sheet article 3 in the passage region 9;
- if APL(FS) is smaller than the lower threshold TPL there are no sheet
articles 3 in the passage region 9;
- if APL(FS) is greater than the upper threshold TPH there are at least
two superimposed sheet articles 3 in the passage region 9, whereby a
drawing error of the sheet articles 3 from the base of the pile 5 is
detectable.
Every above-described calculating operation can be carried out by the
control unit 14 according to the data supplied by the detector device 13
by means of the analogue-to-digital converter 15 (which can be
altemately integrated in the same control unit 14).
From the preceding description it results clear that for detecting and
counting the sheet articles 3 passing across the passage region 9, it is
sufficient to consider even only amplitude or phase detecting of the
signal S2, from.which then it is possible to go back respectively to the
attenuation and the phase displacement of the same signal S2. In this
way, the detector device 13 can be aftemately chosen to supply only a
signal ernitted in direct current (DC), whose values vary according to
the amplitude or the phase of the signal S2.
In order to carry out the above-described operations, which allow to
count the number of sheet articles 3 passing across the passage region
9, it is required to have preliminary measures of amplitude and/or
phase of the signal S2 at the pre-chosen frequency F5 at one's
disposal, in case of no sheet articles passing (values Ao(Fs), Po(Fs)),
only one sheet article 3 passing (values Aj(Fs), P,(Fs)) and two
superimposed sheet articles 3 passing (values A2(Fs), Pz(Fs)); the
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knowledge of these values allows then to define the above-mentioned
thresholds of amplitude TAL, TAH and frequency TPL, TPH.
In practical terms, the control unit 14 can carry out an amplitude and
phase measurement of the signal S2 at the pre-chosen frequency Fs
only one time, with no sheet articles 3 passing in the passage region 9,
storing the values Ao(Fs), Po(FS); in the event of a format change of the
sheet articles 3, it is for example sufficient that by means of a control
panel (not shown) the operator controls at the control unit 14 the
running of an acquisition preliminary phase during which a sheet article
3 according to the new format is released from the pile 5, so that the
control unit 14 itself can store the new values AI(F5), I'l(FS). It has to
be precised that in the event of a format change of the sheet articles 3,
in which material and/or dimensions and/or thickness of the same sheet
articles 3 change, the curve indicated by #1 in the graphs of figures 4A,
4B can undergo even sensible variations, that have to be considered in
order to count the sheet articles 3.
The values A,(FS), P1(FS) associated to every type of sheet articles 3
can result pre-loaded in the storage of the control unit 14 or can be
stored from time to time in the event of a format change, by carrying out
the starting acquisition phase; in such case, from the control panel the
operator can select the new pre-chosen format by a list of available
formats or can control said acquisition phase.
This is extremely advantageous because it makes very easy and fast
the format change operation of the sheet articles 3, which can be
carried out by means of essential controls given by the control unit 14
by means of a standard user-interface connected to the latter, as for
example the above-mentioned control panel;. skilled personnel manual
interventions to adjust mechanical portions of the detecting and
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counting device 100 are therefore not required.
The values A2(FS), P2(Fs) can be determined: by means of a further
acquisition phase, in which two superimposed sheet articles 3
according to the new format pass; or by means of a calculus algorithm
based on the yet acquired values A1(FS), I'I(FS). However, it is to be
precised that these values A2(FS), P2(FS) are not indispensable to
determine the thresholds of amplitude TAL, TAH and frequency TPL,
TPH.
In general terms, the control unit 14 can also provide different'
functioning ways of the device 100 in order to detect and count the
sheet articles 3, and so to carry out more complex calculus algorithms,
based for example on detecting a plurality of amplitude and/or phase
values of the signal S2 for corresponding value of frequency between
Fo-5*Fo/Qo and Fo*5*Fo/Qo.
According to the claims, it is eventually to be precised that in order to
accomplish the present invention, in the device 100, electromagnetic
resonators different from those of "recess" type can be used, which are
shown in the appended drawings.
The present invention is advantageous in that it defines a device for
detecting and counting sheet articles, intermittently released by a feeder
device which satisfies the prefixed objects, brilliantly solving every
drawback lamented in the introduction, peculiar to the known devices;
therefore, it has been defined a reliable, precise, compact, versatile
device which can be easily integrated inside feeder devices of known
type as well and whose costs are relatively reduced with respect to the
achieved advantages.
The thus defined detecting and counting device has therefore the
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function of constantly monitoring the correct functioning of the sheet
feeder 10; in case of wrong releasing of more superimposed sheet
articles 3 from the pile 5 of the feeder 10, such device 100 detects a
wrong condition. By way of a not limiting example, after such a wrong
condition, processed by the control unit 14, a corresponding error
signalling to the central processing unit,of the packaging machine, an
error signalling on the control panel and/or the emission of an acoustic
signal can follow:
The present invention is further advantageous in that it defines a
method for detecting and counting sheet articles, intermittently released
by a feeder device which.satisfies the prefixed objects, brilliantly solving
every drawback lamented in the introduction, peculiar to the known
devices; therefore it has been defined a newly designed method
distinguished by an essential number of operating steps, which allows
to precisely and reliably detect and count the sheet articles released by
a feeder device and whose implementation costs are relatively reduced
with respect to the achieved advantages.
It is intended that the preceding description is purely exemplary and not
limiting, therefore possible practical-applicative variations are intended
to fall into the protective scope of the invention, e,s defined by the
following claims.
