FIELD OF THE INVENTION
This invention relates to an apparatus for forming a stack of sheet-like
objects, in particular but not exclusively a stack of banknotes formed in a cashbox.
Various devices are known for forming stacks of banknotes. One such
device is described in published European patent application No. 0684929. This
discloses an apparatus which incorporates a pusher plate with which a banknote
may be pushed from the plane along which the banknote is transported to the stacking
mechanism (transport plane), into a cashbox situated adjacent to the banknote plane.
The pusher plate is connected by a pivoted lever arrangement via a cam, to a drive
motor. The pivoted lever arrangement operates with a "scissors action" to cause
the pusher plate to push the banknote into the cashbox against the action of a
spring mounted stack surface. The banknotes are retained in a stack in the cashbox,
when the pusher plate is withdrawn, by flanges which abut the ends of the uppermost
surface of the banknote stack.
Other stackers with a vertical scissors arrangement driving a pusher
are disclosed in US 4807736, EP 0751487, US 4809966, US 5344135, US 5421443, US
4765607, US 5419423, and US 4784274.
Although this type of arrangement provides an efficient method of
stacking banknotes, the required depth of stroke of the pusher plate is linked
to the size of the aperture through which the banknote is pushed. Thus, a short
depth of stroke is only possible if the aperture is relatively large. However,
cashboxes with relatively large apertures suffer from the disadvantage of being
difficult to make secure (i.e. self closing) on detachment from the stacking device.
Also, where the cashbox is used with multiple denominations of notes (having different
widths), the aperture must be significantly shorter than the width of the shortest
banknote to be stacked. This is in order that the flanges at the ends of the aperture
may retain even the shortest banknotes. This results in a minimum length of pusher
plate stroke being further increased in order to successfully stack the widest
banknotes through the same aperture size and hence a corresponding increase in
the depth of the cashbox.
The cashbox aperture may be made smaller by increasing the depth of
stroke of the pusher plate. However, an increased depth of stroke results in an
increased cashbox depth for any given size of banknote stack. As space is often
at a premium in such circumstances, for example in combined banknote validator
and stacker devices, this too is an undesirable consequence.
US 4809967 and US 5014857 disclose a stacking device of the piston
type which aims to address the problem of ensuring that banknotes flatten correctly
on the stack surface during the stacking process. These disclosures teach to incorporate
pivotally mounted "unfolding" plates in the piston assembly. These are arranged
to displace horizontally as the piston stroke increases in the vertical direction;
thus assisting in flattening a banknote against the stack.
However despite assisting with flattening banknotes in the stacking
procedure the device of US 4809967 and US 5014857 suffers from the same drawback
as that of EP 0684929A, in that a short depth if stroke is only possible of the
cashbox aperture is relatively large; or, conversely a small aperture is only achievable
if the stroke length is relatively long.
US 6244589 shows a stacker which is arranged to stack through a relatively
narrow aperture (thus providing enhanced security) with a relatively short stroke
(thus making efficient use of cashbox volume), using, in one embodiment, a pair
of rotor arms.
The present invention is intended to provide a stacker capable of
operating through a narrow aperture, with a short stroke, and having a compact
construction. These objects, separately or together, are achieved by the aspects
of the invention defined in the claims.
Other aspects and embodiments of the invention, with corresponding
objects and advantages, will be apparent from the following description and claims.
The invention will now be illustrated, by way of example only, with
reference to the accompanying drawings, in which:
BRIEF DESCRIPTION OF THE DRAWINGS
- Figure 1 illustrates a banknote handling machine including a cashbox with which
a stacking mechanism according to the present invention may be used; and
- Figure 2 illustrates a sectional view through a portion of Figure 1;
- Figure 3a is an isometric view of a cashbox and stacker arrangement according
to an embodiment of the invention;
- Figure 3b is an end elevation showing the end not visible in Figure 3a;
- Figure 3c is a side elevation showing the side not visible in Figure 3a, and
to the same scale as Figure 3b; and
- Figure 3d is a further end elevation to the same scale as Figures 3b and 3c,
showing the end visible in Figure 3a;
- Figure 4a is an isometric view of lateral elements of a pusher forming part
of the embodiment of Figures 3a-d in a retracted condition; and
- Figure 4b is a corresponding isometric view of the same components in an extended
- Figure 5a is an isometric view showing the lateral elements of Figure 4 within
the pusher of the embodiment in an initial state of the pusher cycle;
- Figure 5b is an isometric view showing the pusher extended to full depth with
the lateral portions beginning to extend; and
- Figure 5c shows the lateral portions fully extended (corresponding to Figure
- Figure 6 is a schematic diagram showing the stack support structure within
- Figure 7 (comprising Figure 7a and Figure 7b) shows schematically the cam tracks
of two cams of Figure 3 when projected onto a flat surface;
- Figure 8a is a schematic sectional side elevation (along the length of the
banknote path) showing the stacker in an initial position; and
- Figure 8b is a corresponding sectional end elevation (across the banknote path)
in the initial position;
- Figures 9a and 9b correspond to Figures 8a and 8b in a second stage of the
- Figures 10a and 10b correspond to Figures 8a and 8b in a third stage of the
stacker stroke in which the stacker is fully extended;
- Figures 11a and 11b correspond to Figures 8a and 8b in a fourth stage of the
stacker stroke; and
- Figures 12a and 12b correspond to Figures 8a and 8b and show the stacker in
a fifth and final stage of the stacker stroke.
Referring to Figures 1 and 2, a banknote stacking system according
to the first embodiment of the invention is shown. The system comprises a banknote
transport system, a stacking mechanism and a cashbox 5. The stacking mechanism
and the transportation mechanism are housed in a banknote handling apparatus, such
as a validator, to which a cashbox 5 is removably attached.
Referring to Figure 1, a banknote validating machine 100 is shown
in conjunction with a cashbox 5. Referring now to Figure 2, an idealised sectional
view through the machine 100 is shown. This shows a banknote 1 on the point of
being inserted into an aperture 101 from where it is transported along a banknote
transportation system 102 by a drive unit 103 and validated by a validation apparatus
104. The transportation system 102 then transports the banknote 1 to a stacking
arrangement 105 so that the banknote 1 may be stacked in the cashbox 5 as will
be described. The stacking arrangement 105 may be located in the validator 100
as it is shown in Figure 2 or alternatively in the cashbox 5 itself.
Banknote transport system
A banknote 1 is transported to the stacking mechanism in a direction
perpendicular to the plane of the diagram by the transportation mechanism, which
comprises opposing pairs of rollers 2a, 2b and 3a, 3b. The banknote 1 is engaged
by transportation rollers 2a, 2b, 3a, 3b parallel to its lengthwise edges. That
is to say it is transported in the direction of its longitudinal axis. The spacing
between the pairs of rollers 2a, 2b and 3a, 3b is arranged such that even the minimum
size of banknote for which the mechanism is designed may be securely held and transported.
The rollers 2a, 2b, 3a, 3b position the banknote 1 above an aperture
7 of the cashbox 5. In this embodiment, the aperture 7 is approximately half of
the width of the banknote; i.e. approximately 37mm across. This is suitable for
banknote widths of 62-85mm. The position of the leading edge of the banknote 1
is sensed using photosensors (not shown), or other suitable position sensing devices,
which are occluded by the banknote 1 when it is in the correct position. The output
from the photosensors is then used to inhibit further transport of the banknote
The rollers 2a, 2b, 3a, 3b are located on either side of the aperture
7, such that the banknote 1 is gripped with a positive force and held flat and
parallel to the aperture 4 prior to being stacked.
Stack support mechanism
Referring to Figure 6, as shown schematically therein, the stack
support mechanism for supporting notes in the cashbox 5 comprises a stack support
surface 9 located inside the cashbox and biased towards the aperture 7 by a compression
spring 10. Notes are retained in the cashbox by upper retaining walls 6a, 6b at
the top of the cashbox, the edges of which define the aperture 7.
Referring to Figure 3, and in particular to Figure 3a, the cashbox
5 of Figure 6 is mounted beneath a plate 18 which carries the stacker assembly.
Mounted to an outer wall 19 of the cashbox 5 is a motor 20, the output
of which is coupled to a drive shaft 22 driving a gear wheel 24 which meshes with
a second gear wheel 26 which in turn meshes with a third gear wheel 28.
The gear wheels 26, 28 (which are therefore driven to rotate in opposite
senses by the output gear wheel 24) respectively mesh with toothed rings 27, 29,
each of which is solid and co-axial with a respectively rotary cam, 30, 32.
The cams 30, 32 each carry a similarly shaped cam surface in the form
of a continuous cam track distributed around the cylindrical radius of the cams
30, 32. The track comprises a recessed groove. The tracks (projected onto a flat
surface), and the corresponding timing relationships between the extension strokes
of the pusher and its lateral portions, are shown in Figures 7a and 7b respectively.
The first cam 30 is employed to move the pusher into the cashbox 5
(as will be discussed in greater detail below). The track it carries comprises
a first radial portion 31a distant from the body of the cashbox; a second radial
portion 31b closer to the body of the cashbox 5; and, connecting the two radial
portions, a pair of spiral portions 31c, 31d spiralling in opposite senses around
the axis of the cylindrical cam.
The cam track on the second cam 32 comprises a first radial portion
close to the body of the cashbox; a second radial portion (much shorter than that
of the first cam) distant from the body of the cashbox 5; and, connecting the two
radial portions, a pair of spiral portions spiralling in opposite senses around
the axis of the cylindrical cam.
Engaging with each of the cam tracks is a respective cam follower
34, 36 which comprises a pin or peg, located above the cam bodies 30, 32, each
of the pins 34, 36 being arranged to slide within its respective cam track.
It will be apparent from inspection of Figures 3a-3c that the operation
of driving the motor 20 causes the cams 30, 32 to rotate in opposite senses, and
that as the rotation takes place, the cam followers are displaced from their initial
position (close to the cashbox 5) in which they lie within the first radial portion
of the track, to an extended position as they follow the first spiral portion to
the second radial portion, and then to return back to the initial position as they
follow the second spiral portion back to the first radial portion.
Each stroke of the stacker is executed by causing one rotation of
the cams 30, 32 (corresponding to several rotations of the drive shaft since the
gears execute a reduction).
The first cam 30 will cause the pusher to be displaced into the cashbox
(as described in greater detail below); to remain in the cashbox for a time corresponding
to the time the cam follower 34 lies within the second radial portion of the spiral
tracks; and to return out of the cashbox.
The second cam 32 drives laterally extended portions of the pusher,
as will be described below in greater detail. The cam track on the second cam 32
is radially positioned (i.e. positioned in rotational phase) relative to that on
the first cam 30, such that the first and second spiral portions and second radial
portion of the second cam 32 is occupy the same rotational position as the second
radial portion of the first cam 30. The first radial portion of the second cam
32 therefore occupies the same radial portion as the first radial portion of the
first cam and the two spiral portions thereof.
Between the pairs of rollers 2a, 2b; 3a, 3b there is a note path passing
from an input opening at a first end of the cashbox (visible in Figures 3a and
3d) to a position in which the note directly overlies the aperture 7 in the cashbox
Above the note path, and between the pairs of rollers 2a, 2b; 3a,
3b, is the stacker arrangement. The stacker arrangement comprises an upper portion
105a which remains above the note path, and a lower portion 105b which descends
into the cashbox. A pair of vertically acting scissors linkages interconnects the
Referring to Figures 4a, and 4b, the lower portion comprises a lower
plate 52 carrying a pair of end walls 54a, 54b. The width of the lower plate and
half plates in the retracted positioned is 29mm, which is slightly less than the
aperture 7 (to allow a clearance with a banknote 1 at either side).
Above the lower plate 52 is a lateral extension structure comprising
a pair of half plates 56a, 56b each of lengths slightly less than the lower plate
52, and having half (or slightly less than half) the width of the lower plate 52,
so that in the retracted position shown in Figure 4a, the half plates 56a, 56b
occupy no greater width than the lower plate 52, and sit directly above it and
within the end walls 54a, 54b.
At their outer sides, the lower plates 56a, 56b carry lengthwise running
shallow walls 58a, 58b; the outer edges between the lower plates 56 and their
respective outer walls 58 are smoothly chamfered with a relatively large radius
to allow them to move out over a banknote and smooth the note down without tearing.
At the centre of the lower plate 52, it carries an upright stub, which
is mounted through the centre holes of a pair of cross arms 62a, 62b forming a
horizontally-acting scissors linkage for extending the half-plates 56a, 56b.
At each end of the two arms 62a, 62b (which are symmetrical about
the central stub 60) are slots 64a-64d which are slideably mounted on stubs 66a-66d
carried on the half-plates 56a, 56b.
Towards one end of the half-plates 56a, 56b, a pair of the stubs 66a,
66d are interconnected by helical tension springs 67. The spring 67 operates to
bias the half plates 56a, 56b together into the retracted position of Figure 4a.
Towards the other end, the two arms 62a, 62b are interconnected by
a linkage comprising pair of elongate links 69a, 69b, one end of which is pivotally
connected to a respective arm 64a, 64b, and the other ends of which are pivotally
connected together. The lower plate 52 carries a stub 72 which prevents the two
links from reaching alignment in a straight line.
The two plates can be moved to the extended position of Figure 4b
by providing a force acting on the interconnection point between the two links
69a, 69b, in the direction of the centre stub 60 of the lower plate 52.
This will open the two plates 56a, 56b until the two links 69a, 69b
impinge upon the abutment stub 72 to provide the extended position shown in Figure
4b, at which the width between the edges of the half plate 56a, 56b corresponds
to the width of the widest banknote to be spread onto the stack.
Referring to Figures 5a-5c, in which surrounding parts have been
omitted for clarity, the upper plate 18 carries the upper part of the stacker in
the form of a rectangular raised wall comprising upper end walls 64a, 64b and
side walls 64c, 64d. In the fully retracted position of the pusher stroke, the
lower portion of the pusher (shown in Figures 4a and 4b) is retained within the
upper portion comprising the four walls 64a-64d so as to lie above the banknote
plane. Lower portion end walls 54a, 54b lie just within, and aligned with, upper
portion end walls 64a, 64b.
A pair of vertically acting scissor linkages interconnects the upper
and lower portion end walls. The upper end of each scissor linkage is supported
by one of the upper portion end walls 64a, 64b and the lower end by one of the
lower portion end walls 54a, 54b.
Each of the linkages comprises a pair of arms 66, 68; 70, 72. Each
pair is pivotally connected together at a centre point 74, 76. As the linkages
are identical, only the linkage 66, 68 which is shown in Figure 5 will be discussed
further, it being understood that the same comments apply to the other linkage.
One end (the left hand end shown in Figures 5-5c) of each of the arms
66, 68, is connected at a pivot point at one of the upper or lower end walls,
and the other carries a pin which slides in a horizontal slot in the other of the
end walls. In the fully retracted position of Figure 5a, the arms 66, 68, 70, 72
lie almost horizontally, with the pins at the outer ends of the slots, and in the
fully extended state, shown in Figure 5c, the arms extend downwards at approximately
70° from the horizontal, with the pins at the inner ends of the slots.
Referring once more to Figures 3a-3d, the actuation mechanisms for
the scissors linkages of the stacker system will now be described.
The first cam follower 34 is connected to an elongate plate 36 running
lengthwise along the note path. The movement of the first cam follower 34 longitudinally
inwards of the cashbox, at the beginning of the pusher stroke, causes the elongate
plate 36 to slide longitudinally, which pushes two pivoting links 78a, 78b laterally,
which in turn push the upper ends of arms 68, 72 laterally in their slots, to extend
the scissors linkage and extend the lower portion downwards into the cashbox.
Likewise, as the elongate plate 76 is driven back longitudinally
outwards to the position shown in Figure 3a at the end of the stroke, the upper
ends of the arms 68, 70 are pulled back to the outer edges of the slot by the
links 78a, 78b, restoring the lower portion to the initial (retracted) state of
The second cam follower 36 is connected to a sliding link 40 comprising
a pair of side walls 42a, 42b interconnected by an upper cross bar 44. Each of
the side walls 42, 42b carries a pin which extends inwardly through a lengthwise
slot (not shown in Figures 5a-5c) in one of the side walls 64c, 64d of the upper
Within the upper portion, interconnected the sliding link 40 with
the actuating linkage 69a, 69b, is a Y shaped link 46. The ends of the two arms
of the Y shaped linkage 46 are connected through the slots in the side walls 64c,
64d to the pins carried by the sliding link 44. At its other end, the leg of the
Y shaped link 46 is connected to the pivot point connecting the lower portion
scissors-actuating links 69a, 69b.
As shown in Figure 3a, in the fully retracted position of the stacker
assembly, the Y shaped link 46 lies flat on top of the arms 62a, 62b defining
the horizontally-acting scissors linkage with extends the lateral portions of the
Referring to Figures 8 to 12, the operation of the stacker will now
be described during a stacking stroke.
A banknote note 1 to be stacked is moved by the transport system
comprising the pairs of rollers 2a, 2b, 3a, 3b to a position in which it overlies
the aperture 7 and underlies the stacker.
As shown in Figures 8a and 8b, the stacker is now in the initial state
shown in Figure 3, 4a, and 5a. The lower portion is retracted within the upper
portion, and the stacker is above the banknote 1.
At this point, the control unit of the document handling system (not
shown) actuates the motor 20 to start driving. This causes the cams 30, 32 to
rotate. The cam follower 34 which is initially in the outer radial portion 31a
of the track enters the first spiral portion 31c and consequently drives the elongate
plate 76 longitudinally away from the cam 30.
This actuates the pivoted linkages 78a, 78b to act on the legs of
the vertically acting scissors linkages, to extend those linkages and move the
lower portion downwards into the cashbox into a position shown in Figures 9a and
9b and Figure 5b, engaging the note stack 4. The lower leg of the Y shaped link
46 has descended with the lower portion of the stacker, and the upper arms remain
within the upper portion, so that the link lies diagonally as shown in Figure 9a.
The central portion of the banknote 1 has been pushed into the cashbox 5 onto the
stack 4, and the sides of the banknote 1 extend around the lower portion and protrude
from the aperture 7.
It will be seen that the lower portion needs to descend only to a
depth sufficient to allow the lateral portions to be extended beneath the upper
walls 6a, 6b of the cashbox.
Having reached the second radial region 31b of the cam track, the
cam follower 34 remains at a constant longitudinal position and the lower portion
therefore remains at a constant depth within the stacker for an interval of time
corresponding to the length of the second radial portion 31b.
At this point, however, the second cam follower 36 enters the first
spiral portion 33c of the cam track of the second cam 32 and thus causes the sliding
link 40 to be progressively displaced towards the cam 32. The sliding link 40 in
turn pulls the two arms of the Y shaped link 46 laterally, which act upon the links
69a, 69b to straighten the links and force apart the arms 62a, 62b making up the
horizontally-acting scissors linkage, to the position shown in Figures 10a and
10b, corresponding to Figures 4b and 5c.
The progressive displacement of the half plates 56a, 56b over the
projecting sides of the banknote 1 pushes the banknote entirely through the aperture
7 and substantially flat against the stack 4 as shown in Figure 10b.
Next, the cam follower 36 enters the second spiral region 33d, driving
the sliding link 40 back, together with the Y shaped link 46, so as to release
the pressure on the links 69a, 69b to allow the lower scissor arms 62a, 62b to
close again under the influence of the spring 67.
The stacker thus reaches the position shown in Figures 11a and 11b
(corresponding to Figures 4a and 5b). The note 1 now forms the top of the stack
4. The cam follower 36 re-enters the first radial region 33a.
The cam follower 34 now enters the second spiral region 31d of the
cam track of the first cam 30, retracting the vertical scissors linkages to draw
the lower portion back up inside the upper portion and out of the cashbox 5 through
the aperture 7, to reach the position shown in Figure 12a and 12b when the cam
follower 36 re-enters the first radial portion 31a of the first cam track.
At this point, the stacker stroke is complete, and when a further
note is positioned over the aperture 7, the stacker is ready to repeat the stacker
It will be apparent from the foregoing that the above-described embodiment
provides a stacker which can operate through a relatively narrow cashbox aperture
7 (providing good security) with a relatively short stroke length (making efficient
use of the volume of the cashbox 5).
Furthermore, it does so using a stacker structure which occupies a
very low volume above the banknote path, and consequently reduces the total size
of the cash handling device into which it is fitted.
This is achieved in particular by providing that the pusher comprises
a lower portion which nests into an upper portion, without connecting walls between
the two, so that the maximum length of the stacker is dictated by the depth of
the lower portion rather than corresponding to the maximum stroke length of the
This is further achieved by a providing a scissor linkage as the drive
mechanism for vertical displacement of the stacker, since such a linkage can fold
up to occupy a narrow vertical extent (corresponding to the width of the scissor
arms) when retracted.
This is further achieved by providing that the laterally extending
portions are driven by a horizontally acting scissors linkage (or, in more general
terms, one which acts transverse to the stacking direction of the pusher and roughly
parallel to the plane of the note stack and aperture).
This is substantially flat and therefore has relatively little vertical
extent, but can provide a wide displacement of the lateral portions of the stacker.
It will be clear that the wider the extension of the lateral portions of the stacker,
the shorter is the necessary maximum length of the vertical stroke (for a given
width of cashbox aperture 7).
The skilled reader will understand that a banknote stacking apparatus
according to the present invention may be used in various applications, particularly
those where banknotes are automatically accepted and validated such as in automated
vending machines and banknote changing machines.
It will be apparent from the forgoing that various modifications and
variations may be employed in relation to the above-described embodiments without
departing from the spirit or scope of the present invention. In particular, features
of the embodiments described may be employed individually or in individual combinations
without departing from the scope of the invention.
For example the skilled reader will appreciate that the present invention
could be used to insert documents, such as banknotes, loosely through an aperture;
thus obviating the need for any stack supporting means.
Although in a preferred embodiment the lateral extension takes place
whilst the pusher is held at a constant depth portion of its stroke, it will be
appreciated that the beginning and/or end of lateral extension could take place
whilst the pusher is still moving vertically, provided that most of the lateral
extension takes place whilst the pusher is stationary. Naturally, minor vertical
movements of the pusher such as to approximate constant depth behaviour are also
within the scope of the invention.
Furthermore, the skilled reader will appreciate that by adjusting
the clearance between the upper and the lower halves of the banknote transport
mechanism, the present invention could be used to stack bundles of banknotes,
which have been held, for example, in a temporary storage device such as an escrow.
The skilled reader will also appreciate that various modifications
may be made to the drive mechanism. For example, the banknote transport mechanism
may be arranged to deliver banknotes for stacking at predetermined intervals,
allowing the continuous operation of the stacking mechanism. Although rollers are
used in the present embodiment for the transportation of the banknotes, a belt
driven transportation system could alternatively be used.
Although banknotes are described, other flat sheets having a value
(for example, predetermined value payment coupons) could be employed.
Although a pair of lateral extending portions are described, a single
such portion on one side could be used, the pusher then being positioned to the
other side of the note. Many other variants and modifications are possible.