Note: Descriptions are shown in the official language in which they were submitted.
CA 02173675 2006-O1-06
DE LA RUE GIORI S.A. LAUSANNE/SWITZERLAND
Counting disk of a sheet counter
FIELD OF THE INVENTION
to The invention relates to a counting disk of a sheet
counter for sheets arranged in stack form, in particular
notes of value.
PRIOR ART
Sheet counters with vacuum-operated counting disks
are known and serve, in particular, to count bank notes
which are either already bundled together with a
banderole or located loosely on upon the other without a
banderole. In particular, a counter with the counting
2o disk described in the preamble of claim 1 is known 'under
the SHEETMASTER tradename and is sold by the British
company DE LA RUE SYSTEMS Limited, which has also already
developed other vacuum-operated sheet counters, as are
described, for example, in US-PS 4,350,331. Furthermore,
a counter with a counting disk having only one suction
and counting section is known, for example, from
GB-PS 744 957.
The intermittent connection of the counting opening
and the suction openings to the negative-pressure source
3o takes place by means of a fixed transfer block which
rests against the counting disk and has openings which
are in connection with the negative-pressure source and
are arranged such that,
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CA 02173675 2005-11-09
upon rotation of the counting disk, they temporarily
overlap the inlet openings of the suction ducts provided
in the counting disk. Said fixed transfer block thus acts
as a valve plate.
In the case of the abovementioned known counting
disk, the suction ducts opening in the suction hollow of
a circumferential section run obliquely with respect to
the disk plane and terminate, outside the center of the
suction hollow, in the lateral hollow region facing the
center point of the disk, with the result that the
suction-air direction is oriented obliquely with respect
to the disk plane, and thus with respect to the plane of
the sheet to be counted, essentially tangentially with
respect to the curved hollow wall. Consequently, a
comparatively high negative pressure has to be used in
order that the suction openings are sealed satisfactorily
by the paper sheet, this entailing a correspondingly high
consumption of air and a stronger suction force than
would actually be necessary for raising up a sheet corner
from the sheet stack located behind it. In addition, the
known counting disk only has three suction openings in
each suction hollow.
SUMMARY OF THE INVENTION
As embodied and broadly described herein, the
present invention provides a counting disk of a sheet
counter for sheets arranged in stack form, in particular
notes of value, said rotatable counting disk having
circumferential sections arranged at regular intervals on
a border of said disk, each circumferential sections
having (i) a protrusion projecting in the direction of
rotation of the disk, (ii) a counting opening, a
pneumatic counting pulse being triggered when said
opening is covered by a sheet, (iii) a suction hollow,
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CA 02173675 2005-11-09
whose width and depth increase in the direction counter
to the direction of rotation of said disk, and (iv) a
group of suction openings located one behind the other,
arranged in said suction hollow and can be connected
intermittently, via suction ducts, to a negative-pressure
source, such that, during operation, said circumferential
sections leaf through all sheet corners of a sheet stack
one after the other, separate these from one another in
the process, under the action of suction and deformation,
and cause each sheet to be counted, wherein said suction
openings are centrally located in said suction hollow and
wherein said suction ducts comprise duct sections that
open into said suction openings and that are directed
essentially perpendicularly with respect to the disk
plane and with respect to the base of the suction hollow,
and wherein the suction force thus acts centrally on said
suction hollow and perpendicularly with respect to the
base of said suction hollow.
Since the suction air is directed
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perpendicularly with respect to the plane of the sheet
corner to be raised up and since said suction air acts
centrally on the hollow, the sheet corner is reliably
sucked into the hollow and is positioned in a
positively locking manner on the suction openings, with
the result that good sealing is ensured. Consequently,
a lower negative pressure, and correspondingly lower
consumption of air, may be used than has been common
hitherto, which eliminates the risk of two sheets which
rest against one another being subjected to suction
simultaneously. Moreover, the suction force can be set
precisely in dependence on the paper quality.
In addition, the shape of said suction hollow
and the suction forces are preferably such that a first
sheet along which a suction hollow is sliding will be
curved into said hollow, whereas a second sheet lying
underneath said first sheet will be pulled at the most
until half of said hollow and, because of its inherent
stability, will not undergo any further deformation.
Preferably, five to seven suction openings, in
particular six suction openings, are provided for each
suction hollow.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in more detail by
way of an exemplary embodiment and with reference to
the drawings, in which:
Figure 1 shows a side view of a counting disk
with fixed transfer block and a holding-down device for
the raised-up sheets,
Figure 2 shows, on an enlarged scale, a plan
view of the front side of the counting disk according
to Figure 1,
Figure 3 shows a partial view, in section, of
the circumferential sections of the counting disk in
the direction of arrow F3 according to Figure 2,
Figure 4 shows a plan view of the transfer
block, and
Figures 5 to 10 show sections through the six
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suction ducts which open in a suction hollow of a
circumferential section of a disk according to Figure
2, said sections being directed parallel to the disk
axis and running along a disk radius.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The counting disk 1 represented in Figures 1
and 2 belongs to a counter of a type known per se and
has the general configuration of the abovementioned
known counting disk. Provided at regular intervals
along the border of the counting disk l, the direction
of rotation of which is indicated by a bent arrow, are
circumferential sections 2, six circumferential
sections in the example in question, which have a
protrusion 3 projecting in the direction of rotation of
the disk. Each circumferential section 2 has a suction
hollow 4 in its rear region, in relation to the
direction of rotation of the disk, which suction hollow
4 is formed on the underside of the disk in the
representation according to Figures 2 and 3.
Provided at intervals one behind the other in
said suction hollow 4 are six suction openings 5a to
5f, which form the apertures of suction ducts 6, 7.
These ducts run in the interior of the circumferential
sections 2 and of the inner disk body and extend
radially as far as an opening 8 in the disk body, which
opening, as Figure 2 shows, opens on the front side of
the counting disk.
At its front end, the suction hollow 4 is of a
width which is virtually only as large as the diameter
of the suction opening 5a. Continuing from this front
end, the suction hollow 4 becomes deeper and wider
counter to the direction of rotation of the disk, as is
represented in Figures 2 and 5 to 10, and reaches as
far as the rear edge of the relevant circumferential
section 2.
Furthermore, each circumferential section 2
has, behind the protrusion 3 and at a distance in front
of the suction hollow 4, a counting opening 9 which
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opens on the front side of the disk and is in
connection with inner ducts 10 and 11, the duct 10
opening in a slit 14 which is curved concentrically
with respect to the disk axis and is located on the
front side of the disk, and the duct 11 opening in a
slit 13 which is likewise curved concentrically with
respect to the disk axis and is located on the front
side of the disk. The curved slits 14 are located
together with the openings 8 on a first circle
concentric to the disk axis, while the curved slits 13
together with in each case two further openings 15,
these being arranged in each case between two slits 13,
are located on a second, inner circle.
The planar front side 12 of the inner disk body
of the counting disk 1 bears on a fixed, disk-shaped
transfer block 16 whose center point coincides with the
axis of rotation of the counting disk 1 and whose
planar side facing the counting disk is provided with
two openings 17 and 18 in the angle region in which the
counting takes place (Figure 4). The opening 17 is
connected to a negative-pressure source and is located
on the outer circle, concentric to the axis of rotation
of the counting disk, on which the slits 14 and the
openings 8 of the counting disk are situated. The other
opening 18 leads to a vacuum gauge, a so-called
transducer, and is located on that circle on which the
slits 13 and the openings 15 of the counting disk 1 are
situated. As is represented in Figure 4, the opening 17
is offset somewhat by an angle in the direction of
rotation of the counting disk 1 with respect to the
opening 18.
When the counting disk 1, which slides on the
transfer block 16, rotates, then the slits 14 and the
openings 8 temporarily overlap, one after the other,
the opening 17 of the transfer block and are thus
temporarily connected to the suction-air source, while
the slits 13 and the openings 15 of the counting disk
temporarily overlap, one after the other, the opening
18 of the transfe r block, as a result of which, as is
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further explained below, a counting pulse is triggered.
The transfer block 16 thus functions as a valve plate.
As is shown in Figures 5 to 10, each suction
duct comprises a duct section 6, which runs obliquely
outward from the opening 8 and reaches to beyond the
center of the suction hollow 4, and a short duct
section 7 which is oriented perpendicularly with
respect to the disk plane, and thus with respect to the
plane of a sheet to be counted, and opens into the
relevant suction opening 5a to 5f. In the example in
question, as Figure 2 shows, two suction-duct sections
6 in each case are connected to one and the same
opening 8.
The counting of a sheet stack, in particular of
the individual notes of value of a bundle of such
notes, by means of the abovedescribed counting disk
takes place as follows:
The sheet stack is laid against the counting
disk 1, rotating at a constant speed, such that the
plane of a sheet is oriented essentially parallel to
the plane of the counting disk and a corner of the
sheet stack overlaps the circumferential sections 2 in
the angle region of the counting disk where the
openings 17 and 18 of the transfer block 16 are
located. As soon as a circumferential section 2 slides
along the corner of the first sheet, the openings 8 of
the counting disk 1 pass the opening 17 of the transfer
block 16 and, when the beginning of the suction hollow
4 reaches this sheet, the negative pressure which is
produced in the suction openings 5a to 5f connected,
via the transfer block and the ducts 6 and 7, one after
the other to the negative-pressure source, causes the
sheet corner to be sucked against said openings and
deformed.
Figures 5 to 10, which represent sections
through the suction openings 5a to 5f and their
suction-air ducts 7, 6, show schematic illustrations of
the individual stages of this suction and deformation
of the sheet corner, which, in this manner, is raised
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up from those sheets of the stack which are located
behind it.
By virtue of the first suction opening 5a, the
sheet corner is subjected to suction, and successive
contact with the following suction openings Sb to 5f
effects further suction and, in the process, the
increasing deformation of the sheet corner by the
latter resting against the curved base of the deepening
and widening suction hollow 4, and, finally, the sheet
is definitively raised up from the rest of the sheets
and separated therefrom. Since, on account of the
position of the suction-duct sections 7, the suction
air takes effect (in accordance with the arrow in
Figure 10) in the center of the suction hollow 4 and
perpendicularly with respect to the base thereof, and
thus with respect to the sheet subjected to suction,
for a given aspirating intensity, the sheet undergoes
an optimal suction force, which then pulls the sheet
into the suction hollow by deforming it against its
inherent stability or elasticity. A reliable suction,
deformation and separation of the sheet corners is thus
obtained without the necessity of producing an
excessive negative pressure, it being possible,
furthermore, for the negative pressure to be adapted in
a simple manner to the quality, in particular to the
bending behavior, of the sheets.
In particular, the suction cavity and the
suction force are chosen such that a second sheet,
which is underneath the sucked sheet, will be pulled at
the most until half of the suction cavity 4, preferably
at the most until the second suction hole 5b ; from
this place, the force due to the inherent stability of
the sheet will be stronger than the force due to the
remaining suction air applied by the sheet which is
aspirated and maintained in the suction cavity, so that
both sheets separate.
As soon as the circumferential section 2
subjecting the sheet to suction has passed the sheet
corner, the protrusion 3 of the following circumferen-
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tial section 2 passes beneath the deformed, curved up
sheet corner and thus reaches beneath said sheet, as a
result of which it is further separated from the
following sheets and is guided over the counting
opening 9 of said circumferential section 2. In order
that said raised-up sheet remains in the immediate
vicinity of the front side of the circumferential
section 2 and can be subjected to suction by the
negative pressure prevailing in the counting opening 9,
the counting disk 1 has seated upon it a holding-down
device 19 (Figures 1 and 3) which is connected firmly
to said disk and rotates therewith and is in the form
of a ring with blade-like attachments 20 reaching
radially over the raised-up sheet.
While the counting opening 9 slides along
beneath the raised-up sheet corner, the slit 14 of the
counting disk passes the opening 17 of the transfer
block 16 and, immediately thereafter, the slit 13 of
the counting disk passes the opening 18 of the transfer
block 16. Consequently, on the one hand, the counting
opening 9 is connected to the negative-pressure source
via the transfer block and the duct 10, as a result of
which the sheet is sucked against the counting opening
9 and covers the latter, and, on the other hand, the
closure of the counting opening 9 means that a negative
pressure is produced in the duct 11, which is in
connection with the duct 10, and in the opening 18,
which is then in connection with said duct 11 via the
slit 13.
The negative-pressure peak detected by the
vacuum gauge mounted at the opening 18 of the transfer
block 16 is converted, as a pneumatic counting pulse,
into an electric counting signal. The negative pressure
produced is eliminated again via the holes 15 of the
counting disk which pass the opening 18 thereafter. If
no sheet is guided over the counting opening 9 and the
latter thus remains open, no negative pressure can be
produced in the opening 18 and it is also not possible
for any counting pulse to be produced.
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As soon as the first suction opening 5a in the
suction hollow 4 reaches the next sheet of the stack,
the described suction and deformation operation is
repeated for the second sheet, which, after being
raised up from the rest of the sheets, is counted upon
passing the counting opening 9 in the next
circumferential section 2, and so on. The
circumferential sections 2 of the counting disk 1 thus,
as it were, leaf through the corners of the sheet
stack, which, successively having the protrusions 3
passing beneath them, are counted when sucked against
the counting opening 9, and pass from the rear side of
the counting disk 1 to the front side thereof, until
the entire sheet stack has been counted.
The invention is not restricted to the
described embodiment of a counting disk, but, as
regards the precise design of the circumferential
sections and the suction-air supply means and the
number of suction openings, permits a variety of
variants.
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