Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2Q668 37
CAM ASSEMBLY AND FEEDER MECHANISM FOR USE IN A
PACKAGING MACHINE
The invention relates to a cam assembly and feeder
mechanism for use in a paperboard carton packaging
machine where the mechanism performs the function of
withdrawing carton blanks sequentially from a hopper,
partially or fully erecting each carton blank and
moving it to a point of loading with articles such as
bottles or cans.
Known cam assemblies and feeder mechanisms are
disclosed in EPA182593 which describes a cam assembly
that enables movement of a carton pick-up means along a
rotary path. The pick-up means moves between an
outwardly extended position where it engages a carton
blank and an inwardly retracted position. The known
cam assembly incorporates a cam plate which has a
continuous cam track joined to a second cam track both
of which are defined in the plate such that a pair of
cam followers can be driven round the first continuous
cam track and only one of said cam followers can be
driven round said second cam track. Each of the cam
tracks and cam followers are distinguishable since
according to EP182593 one of the cam tracks is
relatively deeper than the other and both cam followers
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are thus able to move within this deeper cam track.
The other cam track is relatively shallower and since
the cam followers are similarly of different lengths
then only the shorter of the two cam followers is able
to move within the second shallower cam track. By
providing a cam assembly incorporating the two distinct
cam tracks and cam followers as just described an
article pick-up means, such as a vacuum cup,
interconnected with the cam by connecting rods is able
to be moved along a generally eccentric but continuous
locus about a rotary shaft. EPA182593 thus provides
smooth rotational movement of the carton in the feeder
mechanism which provides for increased speed in the
packaging machine. However, movement of the pick-up
means is in a uniform rotational direction, clockwise
or anti-clockwise, about a central axis and it does not
allow for partial counter rotation during the cycle of
said rotation.
According to one aspect of the invention there is
provided a cam assembly for incorporation in an article
feeder mechanism which assembly comprises a cam plate
having formed therein a first continuous cam track and
a second relatively shallower cam track, cam track
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follower means including a first follower for movement within
said first continuous track and a second follower for movement
within the first and second cam tracks, and drive means for
moving said cam track followers with respect to said cam tracks,
said cam tracks, said said track follower means being mounted to
an article pick-up means, said first cam track including portions
engaged sequentially by said first follower, and said second cam
track including portions engaged sequentially by said second
follower, whereby said article pick-up means is caused to move
to an outwardly extended position and to an inwardly retracted
position respectively, relative to a central axis of said cam
plate and said cam assembly is characterized in that said first
and second cam track followers are joined by means of a cam arm
to which a second arm is joined in fixed relationship with said
cam arm, said second arm carries a shaft rotatably connected to
said article pick-up means, and a rotational axis of said shaft
is displaced a greater distance from a central axis of said cam
arm than either central axis of said first and second followers
whereby said article pick-up means is caused to move through both
a like-rotational and a counter-rotational path with regard to
the direction of rotation of said drive means.
2066837
This aspect of the invention provides for a Cam assembly
which enables upward movement of an article pick-up means
thus enabling a carton to be lifted out of a hopper prior
to rotation through to a point where articles are fed into
the carton. A cam assembly according to this aspect of the
invention is therefore a great improvement over the prior
art since more complex movement of both the pick-up means
and carton is enabled thus allowing for greater flexibility
in the design of carton hoppers used in this feeder
mechanism as well as other associated features of the
packaging machine. These improved features can be achieved
whilst still providing or indeed improving the speed of
operation of the paperfeed mechanism.
According to a further aspect of the invention there is
provided a feeder mechanism comprising a cam assembly and
a carton stowage wherein said carton pick-up means removes
an article from said carton stowage during the counter-
rotational movement of said pick-up means relative to the
ro , ~ e means.
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An embodiment of a cam assembly and feeder mechanism
according to the invention will now be described, by
way of example only, with reference to the accompanying
drawings, in which:
FIGURE 1 shows a side elevation and partial cross-
sectional view of a cam assembly according to the
invention;
FIGURE 2 shows an elevation view of a cam plate
incorporated in the cam assembly according to the
invention together with a schematic representation of
the cam assembly during a feed cycle;
FIGURES 3 to 9 show a side elevation of a feeder
mechanism as part of a packaging machine according to
the invention at different times in the carton feed
cycle; and
FIGURE 10 shows a front elevation of part of the feeder
mechanism.
Referring to Figure 1 a cam 10 is shown in partial
cross-section revealing cam tracks 11 and 12. Cam
track 11, is relatively shallower than cam track 12 and
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is adapted to receive only cam follower 21, as opposed
to the axially longer cam follower 22. An elevation of
the cam is shown in Figure 2 where cam followers 21 and
22 are shown schematically at various points in their
rotation about shaft 40. From Figure 2 it can also be
seen that cam track 12 is defined near the periphery of
the cam 10, around most of the cam's circumference.
However, at position X, the relatively shallower cam
track 11 diverges from cam track 12. The tracks
intersect at position Y and cam track 12 is defined
towards the periphery of the cam outside cam track 11.
Both tracks merge at position Z.
Cam followers 21 and 22 are joined by means of an
elongate cam arm 26. According to the specific
embodiment shown in Figure 1, the cam arm 26 comprises
a cam shaft 27 which is rotatably journalled in disc 30
and keyed to arm 50. Wheel 30 is mounted for rotation
upon main drive shaft 40 relative to cam 10. As wheel
30 drives cam arm 26 about shaft 40 relative to cam 10,
cam followers 21 and 22 move in their predetermined
paths and adopt the relative displacement indicated in
figure 2.
Cam followers 21 and 22 are rotatable about axes 1 and
2 respectively in order to minimise friction and
7 20668~7
,
provide a better bearing during movement of cam arm 26.
In this particular embodiment cam shaft 27 has a
symmetry axis 3 which is centered between axes 1 and 2.
Cam arm 26 is further rigidly connected to arm 50 which
is carried by a shaft 52. Shaft 52 which is fixed in
bore 51 of arm 50 at the opposite end of arm 50 to the
fixing of cam shaft 27. The symmetry axis 4 of shaft
52 is displaced a greater distance from the central
axis 3 of cam shaft 27 than the rotational axes 1 and 2
of cam followers 21 and 22 respectively. This greater
displacement distance of axis 4 from axis 3 results in
the small counter rotation movement of vacuum cup 58,
(referred to below) during the uniform rotation of
shaft 40 which drives the cam assembly. It is apparent
that in similar embodiments of the invention the cam
shaft 27 may not be centrally disposed on cam arm 26.
Shaft 52 is rotatably journalled in slader block 54,
which is rigidly connected to rod 56 and pick-up 58.
Rod 56 is slidably journalled in collar 57 which is
rotatably mounted on, and not driven by, shaft 40.
Collar 57 has a fixed axial position on shaft 40 but
can rotate freely thereon. Shaft 40 drives wheel 30
which in turn drives cam arm 26, however, cam shaft 27
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is rotatably journalled in wheel 30 and there is
relative rotational movement of cam arm 26 with respect
to wheel 30 as cam arm 26 moves round relatively fixed
cam plate 10. In turn vacuum cup and block 54 rotate
relative to cam arm 26 and shaft 52 and rod 56 is
forced to slide relative to collar 57. The movement of
cam arm 26 and other components is described in greater
I detail later, especially with reference to figure 2.
The vacuum cup 58 is linked to a vacuum generator (not
shown) which is used to create a vacuum within the cup
58 so that the cup can attach to a carton and release
the carton by decreasing and increasing the gas
pressure in cup 58. By timing the vacuum generation
means to create and quench the vacuum at specific times
during the cam assembly rotation cycle a carton can be
picked up and released at appropriate times.
Referring to Figure 2 Position O is indicated which
shows both cam track followers 21 and 22 in cam track
12 together with a schematic representation of cam arm
26, arm 50, rod 56 and the position of the vacuum cup
58. The path which the pick-up means, or vacuum cup
58, follows during the cycle of movement of the
assembly is indicated by locus ~ along which seven
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further positions of these components are specifically
labelled in Figure 2 as positions A, B, C, D, E, F and
G. The individual positions correspond to the sequence
of movement of a carton from a hopper as shown in
Figures 3 to 9 respectively.
Accordingly, Figure 3 shows a side elevation view of a
carton feeder mechanism which is part of an overall
packaging machine. A collection of carton blanks C are
held in a hopper 70 in a collapsed form prior to a
first carton blank C1 being picked up using the
vacuum cup 58 attached to rod 56 shown in Figure 3.
The hopper 70 comprises a base 66 and bottom carton
retaining rim 68 both of which support the carton
blanks and the rim assists in preventing the cartons
from sliding forward out of the hopper. The cartons C
are further retained by means of a paper feed retaining
bracket 60 which comprises a wheel 62 and upper arm 64.
Figure 3 corresponds to the feeder mechanism (and hence
cam assembly) in position A indicated schematically in
Figure 2. This position of the cam assembly
corresponds to cam follower 21 being located in recess
lla of cam track 11 as shown in Figure 2. Cam follower
21 momentarily stays at position lla while cam follower
-- 10 --
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20668~7
22 sweeps through cam track 12 for part of its movement
between points X and Y in cam 10. When the cam
assembly is in this position the vacuum cup 58 is in an
extended position relative to central shaft 40 as
indicated at point A on the locus L. Thus, in Figure 3
the rod 56 and cup 58 are shown in an extended position
and cup 58 is engaged with carton C1.
Figure 4 corresponds to the cam assembly at position B
indicated in Figure 2. In this position cup 58 is
caused to counter rotate with respect to the otherwise
anti-clockwise rotation of the cam assembly about shaft
40 thereby lifting the carton C1, the face of which
lies substantially tangential to the counter rotational
path of the cup, (see for example positions A and B of
the locus described by the cup in Figure 2). The
carton is dislodged into recess 65 in the retaining
bracket 60 by means of the action of the cup 58 and the
guidance of boss 63, retaining rim 68 and the other
cartons C in the hopper. Thus, a lifting action occurs
between positions A and B of the cam assembly, when the
cam assembly reaches position B carton C1 has been
lifted clear of the upper edge 68a of retaining rim 68
whilst the other end of the carton abuts upper arm 64
of the retaining bracket 60. Further rotation of the
2066837
cam assembly about shaft 40 causes cup 58 to move to
position C which corresponds to the carton feeder
assembly configuration shown in Figure 5. It can be
seen from Figure 2 that cam track follower 21 has been
withdrawn from recess lla of cam track 11 and thus cup
58 is withdrawn from its outermost extended position.
Correspondingly, in Figure 5 carton C1 is shown being
pulled out of the hopper 70 and in the initial stages
of erection of the carton, a vacuum having been applied
in the vacuum cup in order to pick up the carton Cl.
At about a time corresponding to position A indicated
in Figure 3, the vacuum cup is able to pull on the
front panel of the carton blank C1. Wheel 62 and
static guide 72 are used to assist in the formation of
the carton into a sleeve. A front elevation of part of
the packaging machine is shown in Figure 10 where the
hopper assembly can be seen to comprise a rearmost
right and left flange F1 and F2 respectively. Wheel 62
acts to restrain the upper panels of the carton C1 as a
front panel is withdrawn by cup 58 whilst flanges F1
and F2 engage end closure flaps of the carton
associated with the rear main panels so that restraint
also is provided to allow the required "opening"
separation of the front panel away from the rear panels
of the carton.
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Position D of cup 58 on locus L shown in Figure 2
corresponds to further rotation of the cam assembly
whereby cam track follower 22 moves towards recess 12a
in cam track 12 and therefore cup 58 is following its
primary rotary path anti-clockwise about shaft 40.
Carton C1 is therefore pulled downwards out of
retaining contact with wheel 62 but still retained by
static guides 72. Thus carton C1 is pulled clear of
the hopper and r~m~i n; ng cartons C feed forward within
the hopper due to gravity so that the next succeeding
carton abuts boss 63 and retaining rim 68. It can be
seen from Figure 6 that carton C1 is almost fully
formed into its tubular shape in which it can receive
articles such as bottles or cans prior to completion
of the carton around these articles.
A further position in the process of withdrawing a
carton from the hopper prior to its complete formation
ready to receive articles is shown in Figure 7. Here,
cup 58 is shown at position E indicated in Figure 2.
Thus cup 58 continues its anti-clockwise rotation about
shaft 40 thereby pulling carton C1 further away from
hopper 70 and as shown in Figure 7 carton C1 is still
partly retained by static guide 72 and thereby
maintained in partly erected position due to the
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opposite action of the vacuum cup 58 and static guide
72. Figures 8 and 9 show further rotation of the cam
assembly where carton Cl is placed between flight bars
80a and 80b which draw carton C1 along a base 82,
although base 82 may itself be a conveyor. Figure 9
shows a fully erected carton in a sleeve form prior to
suction cup 58 disengaging from the upper panel of the
carton. Figures 8 and 9 correspond to positions F and
G of suction cup 58 along the locus L shown in Figure
2.
It is anticipated that by using several of the cam
assemblies according to the invention a packaging
machine may comprise multiple carton feeder assemblies
comprising hoppers as specifically described herein and
thereby enable high speed operation.
