This invention relates to an apparatus and method for
handling objects on a packaging line.
The packaging industry is continually seeking for
faster machines. In such machines it may be desired to
support an object in a container as the container moves
along the packaging line. Insertion of the object in the
container from above at a loading station may be problematic
because the object may be being conveyed prior to insertion
at a different speed from the container into which it is to
be inserted or because the object is in a different
orientation from that required for insertion into the
container or both. Sometimes the object may be approaching
the loading station faster than the container; in other
cases the speed of movement of the container through the
loading station may be faster than that of the object to be
inserted. In order to overcome this difficulty it may be
necessary in conventional packaging machines to slow the
container so that the correct synchronisation and
orientation can be achieved at the loading station. This
has the effect of slowing down operation of the whole
machine. Thus achieving the correct synchronisation of the
object and container at the loading station whilst
simultaneously getting the object in the correct orientation
may be difficult without unduly slowing down the speed of
the packaging machine.
GB-A-1003768 describes an apparatus for the packing of
solid or liquid materials in sealable bags or sachets. This
is a hand operated machine with a carriage movable along a
pathway and supporting a jig adapted to receive a bag. The
jig has double walls, the inner one of which is permeable
and the space between the double walls is connected to a
vacuum for opening the bag under the influence of the
vacuum. A suction cup attached to a tubular arm is used to
transfer a bag from a magazine to the jig. After filling
with biscuits or solid, granular or liquid material the
operator operates a lever which folds over flaps at the
upper end of the jig to fold over the top of the bag,
whereupon the top of the bag is sealed. The sealed bag can
then be removed from the jig, one way of achieving this
being by providing a retractable bottom to the jig.
The present invention accordingly seeks to provide a
method of and an apparatus for reliably inserting an object
into a moving container at a loading station with the
correct orientation of the object and without having to
reduce the speed of movement of the container and hence of
the whole packaging machine. It further seeks to provide an
apparatus and a method which enable the insertion into a
container moving along a first path of an object which is
moving along a second path that converges with the first
path and is possibly travelling at a different speed from
the container.
According to the invention there is provided
apparatus for inserting an object into a moving container at
a loading station comprising:
a support container for an object comprising first and
second separable parts which are laterally separable one
from another to open the container; means for moving the support container in open
condition through a loading station along a first path; means for moving the object along a second path which
converges with the first path so that the object enters the
container between the two separable parts; and means for closing the container with the object inside
it so that the object is supported in said container for
further conveyance along said first path.
The invention further provides a method for inserting
an object into a moving container at a loading station
comprising:
providing a support container for an object comprising
first and second separable parts laterally separable one
from another to open the container; moving the support container in open condition through
a loading station along a first path; moving the object along a second path which converges
with the first path so that the object enters the container
between the two separable parts; and closing the container with the object inside it so that
the object is supported in said container for further
conveyance along said first path.
The first and second separable parts may each include a
bottom wall means and side wall means, the bottom wall means
of the first and second separable parts cooperating in the
closed condition of the support container to form a bottom
wall for the support container and the side wall means of
the first and second separable parts cooperating in the
closed condition of the support container to form side walls
for the support container.
Preferably the support container has a substantially
parallelepipedal interior shape in its closed condition.
The second separable part may be pivotally linked to the
first separable part by means of a parallelogram linkage so
that lateral separation of the separable parts occurs by
virtue of the second separable part swinging laterally
outwardly and downwardly away from the first separable part.
In such an arrangement the first and second separable parts
may include bottom wall means which are arranged to separate
along a first substantially vertical longitudinal plane and
a side wall means of the second separable part can similarly
be arranged to separate from a corresponding side wall means
of the first separable part at at least one longitudinal end
of the support container along a vertical longitudinal plane
that is laterally offset from the first substantially
vertical longitudinal plane. Preferably the bottom wall
means are arranged to separate along a first substantially
vertical longitudinal plane and the side wall means of the
second separable part is arranged to separate from the side
wall means of the first separable part at one longitudinal
end of the support container along a second vertical
longitudinal plane that is laterally offset from the first
substantially vertical longitudinal plane and at the other
longitudinal end of the support container along a third
longitudinal plane that is laterally offset to the other
side of the first substantially vertical plane from the
second substantially vertical plane. In this way an object
inserted into the container along the first substantially
vertical plane cannot emerge from the forward end of the
container because it will first strike the side wall means
of one of the separable parts at the forward end of the
container.
It will normally be convenient for the apparatus to
include also means for locking the support container in its
closed condition.
The object may have a portion which is relatively flat
and flexible, in which case the container can include
opposed portions which grip said portion to locate the
object in the container in its closed condition. Thus the
object may be a flattened bag having a front, a back, and a
bottom seal and the flattened bag may be delivered into the
container so that, when the container closes, the bottom
seal of the flattened bag is trapped between the opposed
portions of the separable parts of the support container.
In one arrangement said opposed portions comprise a fixed
portion on one of the separable parts and a pivotable member
on said one of the separable parts so as to be pivotable
between a closed condition in which said fixed and pivotable
portions cooperate to grip said portion of said object and
the open position in which fixed portion and said pivotable
portion are spaced one from another to allow the object to
enter the container. Preferably the pivotable portion is
biased towards its open position. Moreover said pivotable
portion can be arranged so as to engage a bottom wall
portion of the other separable part and move towards its
closed position as the two separable parts close to support
said object.
In the apparatus according to the invention the means
for moving the object along a path in the same direction
through the loading station may comprise a holder member
carried by an endless belt that is arranged to run about
rollers at the corners of a parallelogram linkage, the upper
pair of rollers being arranged for rotation about fixed axes
and the lower pair of rollers being arranged for rotation
about axes which can be swung at the end of respective arms
through an arc under the influence of a driving member
driven by a cam surface of a cam so that the holder member,
as it passes around the lower run of the parallelogram
linkage, in the direction of movement of the container is
accelerated, by swinging of the parallelogram linkage, in
one direction to a predetermined speed which is greater than
the speed of movement of the container to cause the object
to be carried between the two separable parts of the support
container and then, as the parallelogram linkage swings in
the other direction, to be slowed as it enters the open
support container to the same speed as the container.
The object can be arranged to be engaged with the
holder member as the holder member passes along the upper
run of the endless belt passing around the rollers. The
orientation of the holder member relative to the endless
belt on the upper run of the endless belt can be different
from the corresponding orientation of the holder member
relative to the endless belt on the bottom run of the
endless belt. Thus, for example, the holder member can be
pivotally mounted on a carrier with respect to the endless
belt and in the orientation of the holder member with
respect to the endless belt is changed by engagement of a
cam follower member provided on a crank arm operatively
attached to the holder member and arranged to engage with
cam tracks mounted adjacent the parallelogram linkage.
The container, in one preferred form of the invention,
is adapted to receive a flattened bag having a front, a
back, and a bottom seal and in which the means for moving
the flattened bag is arranged to deliver the flattened bag
into the container so that, when the container closes, the
bottom seal of the flattened bag is trapped between the
bottom wall means of the separable parts of the support
container. In such a form of the invention the bottom wall
means may each be associated with a plenum chamber connected
to respective vacuum connection means and communicating with
the chamber around the flattened bag by means of passageways
adjacent the side wall means of the separable parts whereby,
upon evacuating the plenum chambers through the vacuum
connection means, the chamber around the flattened bag can
be evacuated and the flattened bag opened.
Preferably one of the separable parts includes a plenum
chamber beneath the bottom of the chamber which is in
communication with the chamber around the flattened bag and
is connected to a vacuum connection pipe carrying a bellows
connector, while the other separable part includes a plenum
chamber beneath the bottom of the chamber which is in
communication with the chamber and is connected to a vacuum
connection pipe carrying a bellows connector; in this case a
vacuum box can be mounted adjacent the path of travel of the
container, the vacuum box having a operating face with one
or more orifices which is disposed substantially parallel to
the path of travel of the container, and a flexible belt
having apertures spaced along its length can be arranged to
pass across the operating face of the vacuum box, the
spacing of the apertures and the timing of the belt being
arranged so that, as the container with a bag therein passes
the vacuum box, the bellows connectors can communicate with
the vacuum box thereby to evacuate the plenum chambers and
the chamber around the flattened bag so as to open the
flattened bag.
First and second top closure members in such a case can
be juxtaposed above the support container along the path of
the container after the container has closed, one top
closure member being positioned to be adjacent the front of
the flattened bag and the other top closure member being
positioned adjacent the back of the flattened bag and
laterally spaced one from another by a distance of from
about 2 mm to about 7 mm, preferably from about 4 mm to
about 6 mm.
Preferably the flattened bag will have a longitudinal
seal formed by sealing together opposite side edges of a web
of a sealable material and a gusseted bottom. Such gussets
in the flattened bag may be defined in part by diagonal
seals.
In the apparatus of the invention first and second top
closure members may be positioned above the support
container so that one closure member lies adjacent the front
of the flattened bag and the other closure member lies
adjacent the back of the flattened bag so as to form
together with the bottom wall and the side walls of the
support container a substantially enclosed chamber around a
lower portion of the flattened bag. Such first and second
top closure members may comprise stationary members.
Alternatively, they can comprise endless belts preferably
arranged to move in synchronism with the container as this
is caused to move along its predetermined path.
In order that the invention may be clearly understood
and readily carried into effect two preferred forms of bag
opening and support apparatus constructed in accordance with
the present invention will now be described, by way of
example only, with reference to the accompanying drawings,
wherein:-
Figure 1 is a perspective view of part of a packaging
machine for making evacuated packages each comprising a
sealed, evacuated bag containing a charge of a comminuted
material, such as roasted and ground coffee; Figure 2 is a perspective view on an enlarged scale of
one of the bag containers of the machine of Figure 1, with
the container in its open condition; Figure 3 is a similar view to that of Figure 2 showing
the bag container in its closed condition; Figure 4 is a front view of one of the bag containers
removed from the machine of Figure 1; Figure 5 is a left side view, partly in section, of the
bag container of Figure 4; Figure 6 is a top plan view, partly in section, of the
bag container of Figures 4 and 5; Figure 7 is a detail view of part of one of the
carriages of the machine of Figures 1 to 6; Figure 8 is a perspective view of a device for
delivering flattened bags to the machine of Figures 1 to 6; Figures 9 and 10 are front views of the device of
Figure 8 illustrating its mode of operation; Figure 11 is a further front view of the device of
Figures 8 to 10 showing the cam surfaces for controlling the
attitude of the bag-holding clips; Figure 12 is a vertical section of a modified form of
bag container in closed condition; and Figure 13 is a similar vertical section through the bag
container of Figure 12 in open condition.
Referring to Figure 1, part of a packaging machine 1
for making evacuated packages, for example evacuated sealed
bags containing roasted and ground coffee is depicted. This
has an endless chain 2 (only part of which is shown) which
passes between and around two carousels (not shown) arranged
one at each end of the machine 1. The direction of travel
of endless chain 2 is shown in each of Figures 1 to 3 by
arrows A. Endless chain 2 is used to convey containers 3
for bags 4 around the machine 1 to and from the portion of
the machine 1 which is shown in Figure 1 and which is the
portion of machine 1 in which flat preformed bags 4' are
inserted into the containers 3 and opened out. Thus Figure
1 shows at its right hand side a flat bag 4' about to be
inserted into a container 3 and at its left hand side a
fully opened bag 4.
From the portion of the machine 1 illustrated in Figure
1 the opened bags 4 are conveyed in the direction of the
arrow A to a first carousel at the left hand end of the
machine (as illustrated) where the containers 3 and bags 4
are individually tared, then part filled with a first dose
of roasted and ground coffee, re-weighed, and topped up to a
desired weight with a second dose of the roasted and ground
coffee. The containers 3 with their filled bags 4 then
travel back to the right hand end of the machine 1 along a
reverse path behind the illustrated part of the machine 1 in
the opposite direction to arrow A and pass around the second
carousel which is at the right hand end of the machine 1,
that is to say the right hand end as illustrated. On this
second carousel the filled bags 4 are evacuated and sealed
or are evacuated, gas flushed (with, for example, carbon
dioxide or nitrogen) and sealed. A small amount of a
desirable coffee aroma fraction may be bled into the
evacuated filled bags 4 before the sealing step in order to
enhance the aroma when the sealed package is first opened.
In passage along the reverse path from the first carousel to
the second carousel the bags 4 and their contents may be
tamped by, for example, a brief period of vertical
vibration, in order to settle the contents of the bags 4 and
facilitate formation of a neat parallelepipedal package.
As can better be seen from Figure 2, endless chain 2
consists of links 5 joined one to another with carriages 6
attached to appropriate links 5 at regular intervals.
Carriages 6 are arranged to run on a pair of substantially
parallel level tracks (not shown in Figures 1 to 3) on
rollers 7. A guide roller 8 arranged to rotate about a
vertical axis is mounted on each carriage 6 and runs in a
guide track (also not shown in Figures 1 to 3) mounted where
necessary along the runs of the endless chain 2 and on each
carousel above the carriages 6 so as to assist in preventing
carriages 6 from tipping. A pair of similar guide rollers
(which again are not shown in Figures 1 to 3) which are also
arranged to rotate about a vertical axis are provided on the
underside of each carriage 6. These further rollers run in
a corresponding guide track under the endless chain 2
located between the level tracks for rollers 7; this further
guide track is not shown in Figures 1 to 3.
Each carriage 6 also carries a vertical flanged member
9 which is slidably received in a bracket 10 mounted on the
rear of carriage 6. Member 9 can be raised and lowered at
appropriate moments in the operating cycle relative to its
corresponding carriage 6 by means of a roller 11 which, at
the appropriate moment or moments in the operating cycle of
the machine 1, runs up a stationary ramp surface (not shown)
as it is carried around the machine 1 by the endless chain 2
in order to raise member 9 and the container 3 that it
carries and then runs down a corresponding ramp surface
(also not shown) to lower it again.
As can be seen from Figure 2, member 9 carries at its
upper end a mounting plate 12 for its associated container
3. Mounting plate 12 is provided on its rear face with
three studs 13 with enlarged heads (see Figure 5, which
shows only one of the studs 13). Studs 13 engage in keyways
14 (see Figure 4) in a backing plate 15 on the front of
container 3. This arrangement allows for container 3 to be
released temporarily from its associated member 9 at the
appropriate moment in the operating cycle, specifically for
taring and weighing purposes. A crank arm 16 pivotally
mounted on a pivot pin 17 carries an operating roller 18 and
a locking roller 19 which engages in slots 20, 21 formed in
mounting plate 12 and backing plate 15 respectively to lock
container 3 in place on member 9. A spring 22 is attached
at one end to crank arm 16 and at its other end to a bolt 23
on mounting plate 12 and biases crank arm 16 towards its
locked position, as shown in Figure 3. Operating roller 18
is arranged to bear against a stationary cam track (not
shown) which is shaped so as to move roller 18 to its
unlocked position, shown in Figure 2, at the appropriate
point in the operating cycle of machine 1, as the container
3 is carried along by chain 2, and then to move it back to
its locked position again.
Each container 3 has interior surfaces which define a
substantially parallelepipedal shape. It is split
vertically into two halves 24, 25. The rear half 24 of
container 3 is connected to the front half 25 thereof by a
parallelogram linkage formed by pivoted arms 26, 27 (see
Figure 5) at its left side and by a single pivoted arm 28 at
its right side. In moving from its closed position, shown
in Figure 3, to its open position, shown in Figure 2, rear
half 24 swings downward and rearward away from front half
25. Container 3 is held locked in its closed position by
means of locking levers 29, 30 mounted one at each end of
container 3 which engage respectively with pins 31, 32 on
front half 25. Levers 29, 30 are biased towards their
locking positions by means of respective springs 33, 34.
Locking lever 29 pivots about pin 35 and carries a roller 36
which engages with a stationary cam track (not shown) when
it is desired for container 3 to open. Locking lever 30
pivots about pin 37 and carries a roller 38 which engages
with a corresponding stationary cam track (not shown), which
runs parallel to the corresponding cam track for roller 35,
to open container 3 at the appropriate point along its path.
Roller 38' (see Figure 5) which is carried by rear half 24
is arranged to cooperate with a corresponding cam track (not
shown) to urge rear half 24 back to its closed condition at
a point further along the path of container 3 from that at
which container 3 is caused to open.
Reference numerals 39, 40, 41, and 42 indicate pivot
pins for arms 26, 27, while reference numerals 43 and 44
indicate pivot pins for arm 28.
As can be seen from Figure 6, the two halves 24, 25 of
container 3 are somewhat asymmetrical so that the plane of
separation 45 along which the two halves 24, 25 separate at
the right hand end of container 3 is offset to one side of
the centre line L-L while the plane 46 along which the two
halves 24, 25 separate at the left hand end of the container
3 is offset to the other side of centre line L-L. However,
the two halves 24, 25 separate at the base of the container
3 along the centre line L-L. The walls 24a, 24b, and 24c
and base 24d together define approximately half of a
parallelepiped, the remaining portion of which is defined by
the walls 25a, 25b and 25c and the base 25d of half 25.
The base of the container 3 is provided with plenum
chambers 47, 48 arranged one in each half 24 or 25. These
plenum chambers 47, 48 are covered, except along the edges
adjacent the internal walls of the respective half 24 or 25,
with respective cover plates 49, 50; in Figure 6 the halves
of these cover plates 49 and 50 towards the top of the
Figure have been cut away to show the plenum chambers 47 and
48. Thus there are narrow slit-shaped apertures 51, 52
between the edges of cover plates 49, 50 and the internal
walls of container 3 and larger substantially triangular
apertures 53, 54 in the corners of the bottom of container
3. As can be seen from Figure 6, the corner of cover plate
50 can be cut away at 55. The bottom of container 3 can be
made of magnetic material so that it will sit firmly on a
load cell (not shown) on the first carousel during taring
and weighing, at which time container 3 will have been
released from member 9 by moving crank arm 16 to its
unlocked position and lowering member 9 to cause studs 13 to
move into the larger area parts of keyways 14. Roller 56
(see Figures 2 and 3) is arranged to cooperate with an
appropriately positioned ramp surface (not shown) to impart
a vertical vibratory movement to container 3 to assist in
tamping of the charge of coffee or other comminuted material
after the necessary weighing action has taken place.
The half 24 is provided with a vacuum connection pipe
57 with a flexible bellows connector 58 at its end; this
vacuum connection pipe 57 leads to plenum chamber 47. A
further vacuum connection pipe 59 with a further flexible
bellows connector 60 is provided on half 25. This further
vacuum connection pipe 59 is connected to plenum chamber 48.
Above the path of travel of containers 3 there are
mounted two guide members 61, 62 (see Figure 1); these are
spaced very closely above the tops of containers 3 but are
laterally spaced one from another by about 5 to 10 mm so
that a near air tight enclosure is formed by each container
3 and the guide members 61, 62 as the container 3 passes
under guide members 61, 62. In the region below guide
members 61, 62 there is mounted a vacuum box (not shown)
across whose rear perforated operating face passes an
endless belt (also not shown) which moves in synchronism
with chain 2 and is provided with apertures arranged so as
to marry up with bellows connectors 58, 60 as each container
3 comes past the vacuum box. The rear operating face of
this vacuum box is perforated so that a vacuum can be drawn
through bellows connectors 58, 60 as each container 3 passes
behind and in close proximity to the vacuum box in
synchronism with the apertured endless belt.
As can be seen from Figure 1, a flattened bag 4', which
has a bottom fin seal 63, is suspended vertically from a
spring loaded clip 64 of clothes peg construction for
movement in the direction of arrow A. Each bag (see
flattened bag 4'' in Figure 1) is formed with side gussets
65, 66. Also the bottom end of each bag (see flattened bag
4') has diagonal seals 67, 68. In addition the bag 4' has
been horizontally pre-creased, as indicated at 63' and 63'',
at positions corresponding to where the top and bottom edges
will be in the evacuated filled package. These side
gussets, horizontal pre-creases and diagonal seals assist in
eventual formation of a neat parallelepipedal package.
Figure 7 shows a detail of a carriage 6 and the track
69 on which this runs. Also visible is the roller 70 (to
which reference has been made above) mounted underneath
carriage 6. This runs in a groove 71 in track 69. Roller 8
runs in a corresponding groove 72 above the carriage 6; here
it is illustrated as being in the underside of one of the
carousels 73.
Figures 8 to 11 illustrate a device 74 for feeding the
flattened bag 4' to the container 3, which is in open
condition, at the right hand end of the part of the machine
1 shown in Figure 1 so as to feed the flattened bag 4' along
a path which converges with that of the container 3. Device
74 is also designed so as to impart the desired variation in
speed of movement of the clip 64. Device 74 comprises an
endless belt 75 which is driven in a clockwise direction
around four rollers 76, 77, 78, and 79 which are located at
the corners of a frame in the shape of a floppy
parallelogram formed by members 80, 81, 82, and 83. These
are pivoted one to another by means of fixed pivots 84, 85
and by swinging pivots 86, 87. A cross member 88 is pivoted
to the mid points of members 81, 83 on pivots 89, 90 and
carries a pair of cam follower rollers 91, 92 which engage
with the rim 93 of an elliptical cam wheel 94 which is
mounted on axle 95. (For the sake of clarity cam wheel 94
is omitted from Figures 9 and 10). As cam wheel 94 is
rotated so cam follower rollers 91, 92 follow its rim 93 and
move cross member 88 from side to side which in turn causes
the parallelogram linkage 80, 81, 82, 83 to swing from side
to side. The extremes of this swinging movement are
represented by Figures 9 and 10 respectively.
Belt 75 carries a number of clips 64 which are similar
in construction to spring loaded clothes pegs. Clips 64 are
each pivotally mounted on a shaft that passes through a
respective carrier 96. A spring loaded push rod (not shown)
extends through carrier 96. One end of this push rod bears
against one end of the rear movable arm of peg 64 and the
other end projects from the rear of carrier 96. Pressure
upon the rearward end of the push rod causes clip 64 to
open. Carrier 96 is also provided with rollers 97 which
bear on the edge of the parallelogram linkage 80, 81, 82, 83
as the belt 75 moves around it. The other end of the shaft
on which clip 64 is mounted carries a crank arm 98 with a
roller 99. This roller 99 engages with a cam track 100 as
it passes around the bottom right hand corner of the
parallelogram linkage. This causes the clip 64 to pivot
through 90° until it extends horizontally. As it passes
around the bottom left hand corner of the parallelogram
linkage so roller 99 engages with a further cam surface 101
(see Figure 11) which serves to rotate clip 64 through 90°
again so that when it comes round the top left hand corner
of the parallelogram linkage the clip 64 is again vertical.
In operation of the illustrated machine 1, the endless
chain 2 is driven at a constant speed in the direction of
arrow A. A flattened bag 4', which has a bottom fin seal
63, is suspended vertically from a clip 64 which is also
moved in the direction of arrow A but somewhat faster than
endless belt 2 so that it can overtake the containers 3. As
can be seen from Figure 1 the container 3 at the right hand
end of the illustrated part of the machine 1 is open, the
rollers 36 and 38 having been forced downwards by engagement
with their respective associated ramp surfaces (not shown).
As the flattened bag 4' enters the open container 3 along
its centre line L-L, the speed of clip 64 is reduced to
match the speed of endless chain 2. Thus the flattened bag
4' and the open container 3 are now moving in synchronism.
Next the open container 3 closes by allowing rollers 36, 38
to come off their ramp surface and roller 38' to engage with
its corresponding ramp surface and by letting locking levers
29 and 30 return under the influence of springs 33 and 34 to
their locked positions in which they engage pins 31 and 32
respectively. The bag 4' is positioned at such a height in
relation to the half 25 of the open container 3 that, as the
container 3 closes, the bottom fin seal 63 is trapped
between the bottom edges of the two halves 24 and 25.
Because the container 3 splits into two asymmetric halves 24
and 25 it is impossible for flattened bag 4' to overshoot
the open container 3 since its leading vertical edge will
hit first the inner face of the left hand wall of the open
container 3. Immediately upon closure of container 3, clip
64 which is attached to an endless belt (not shown) opens so
as to release flattened bag 4' and then travels on to pick
up a new flattened bag 4'. Opening of clip 64 is effected
by means of a fixed ramp surface (not shown) mounted behind
the path of clip 64 against which the rear end of its spring
loaded push rod bears so as to move the push rod forward
against its spring to open clip 64. As can be seen best
from the second flattened bag from the right hand end of
Figure 1, i.e. the flattened bag 4'', is formed with side
gussets 65, 66. Also the bottom end of each flattened bag
4' has diagonal seals 67, 68. These side gussets and
diagonal seals assist in eventual formation of a neat
parallelepipedal package.
The now closed container 3, with a flattened bag held
firmly between the bottom edges of the two halves 24, 25
moves on under guide members 61, 62. Once the container 3
is fully under guide members 61, 62, flexible bellows
connectors 58, 60 pass in front of a vacuum box (not shown)
so as to draw a vacuum, via pipes 57 and 59, in the plenum
chambers 47 and 48 respectively and hence via slits 51, 52
and triangular apertures 53, 54 in the main body of
container 3. Because the top of container 3 is at this
point nearly closed by the guide members 61 and 62, except
for a narrow gap between them, air cannot readily enter
container 3 except by entering the flattened bag positioned
therein. As a result, the bag opens very quickly and is
drawn to conform snugly to the inside shape of container 3.
As the container 3 emerges from under the left hand end of
the guide members 61, 62 so the material of the bag tends to
open it further as shown at the left hand end of Figure 1.
The gap between guide members 61 and 62 should not be
so wide, on the one hand, that an effective vacuum cannot be
drawn quickly and without use of excessive power within
container 3 and not so narrow, on the other hand, that the
top of the bag cannot slide down somewhat into container 3
to allow full opening of the bag to occur. A lateral gap of
about 5 mm has been found suitable for bags made from a
printed laminate 100 µm thick consisting of a layer of
polyethylene terephthalate, a layer of low density
polyethylene, and a layer of peelable polyethylene, with the
peelable layer on the inside of the bag. Such a bag can be
used for packaging, for example, 500 g of roasted and ground
coffee.
Turning now to Figures 8 to 11, device 74 is positioned
below the path of movement of flattened bags 4' as they
emerge from a bag forming machine bottom end first. The
direction of movement of the bags 4' is indicated by arrow B
in Figures 8 to 10; arrow A in Figures 8 to 10 corresponds
to arrow A of Figures 1 to 3. As the clip comes around the
top left hand corner of the parallelogram linkage, its push
rod bears against a ramp surface (not shown) which forces it
forward so that clip 64 is opened. The speed of travel of
belt 75 is matched to that of the flattened bags 4' as they
emerge from the bag forming machine pass in the direction of
arrow B, each with its transverse fin seal at its leading
end. The timing of the device 74 is so adjusted that, as
each clip 64 attains a vertical attitude after passing
around roller 76, it receives a flattened bag 4' (as shown
in Figure 9). Clip 64 then closes as the rear end of its
push rod comes off its cooperating ramp surface and carries
flattened bag 4' along with it as it continues to move
towards roller 77.
In order that the overall size of the packaging machine
can be reduced the spacing between adjacent containers 3
along chain 2 is less than the height of a bag 4', for
example approximately one half the height of a bag 4'.
Since the speed of movement of the flattened bags 4' as they
emerge lengthwise from the bag forming machine is greater
than the speed of endless chain 2, it is necessary to slow
the bag 4' as it is inserted into the appropriate container
3 to the speed of chain 2. In addition the design of
machine 1 requires that a flattened bag 4' shall be inserted
into the open container 3 in a vertical attitude, as shown
in Figure 1, although it has been formed in a manner which
results in it travelling bottom end first. The
parallelogram linkage of device 64 allows the flattened bag
4' to be presented in the correct attitude and at the
correct speed for insertion into open container 3.
The swinging movement of the parallelogram linkage is
coordinated with the movement of the clip 64 from right to
left along the lower run of belt 75 so that, as the
flattened bag 4' approaches the open container 3, the
linkage is swinging leftward so that clip 64 is moving
faster than the speed of endless chain 2. However, as the
flattened bag 4' enters the open container 3, the linkage
reverses its direction of swing and commences to swing to
the right, thus reducing the velocity of flattened bag 4'
relative to that of the endless chain 2. As the linkage
swings to the right, the right-to-left velocity of the
flattened bag 4' equates to the corresponding velocity of
the endless chain 2 so that the flattened bag 4' is moving
at the same speed as the container 3 as this closes.
As can be seen from Figure 9, the flattened bag 4' is
travelling endwise from left to right as it first captured
by a clip 64. In passing over the roller 77 its attitude
changes from horizontal to vertical. Then in passage around
roller 78 roller 99 engages with the cam track 100 and
rotates clip 64 through 90°. Thus as it commences to travel
back in a leftward direction along the bottom run of belt 75
flattened bag 4' retains its vertical attitude in readiness
for insertion into the open container 3. In passage around
roller 79 roller 99 engages with cam track 101 which serves
to rotate clip 64 through 90° again in readiness for
capturing a further flattened bag 4'.
Figures 12 and 13 illustrate a modified form of
container which, while generally similar to the container of
Figures 2 to 6, has a trap door arrangement in its base
instead of having a fixed base. In Figures 12 and 13 the
same reference numerals have been used to identify those
parts which are essentially the same as those present in the
embodiment of Figures 2 to 6.
In the front half 25 of the modified container of
Figures 12 and 13 plenum chamber 48 is closed on its upper
side by a fixed part 201 which forms part of the floor to
container 3. The bottom wall means 25d of front half 25
extends somewhat rearward (i.e. to the right as illustrated
in Figures 12 and 13) past the plane of separation 45 and
carries a pivotable member 202 mounted on pivots 203.
Rubber pads 204 and 205 are provided on part 201 and member
202 respectively and grip the bottom end of bag 4' in the
closed condition of the container. Member 202 is spring
biased by means of a spring (not shown) in a clockwise
direction as depicted in Figures 12 and 13. As the two
halves separate, as shown in Figure 13, so member 202 swings
down and away from front half 25 to the position of Figure
13. In this way a wide gap is formed between pads 204, 205
which minimises the risk of the bottom end of a bag 4'
hitting part of container 3 and not entering it correctly.
When the container 3 closes, the lip 206 extending across
the bottom of the bottom wall means 24d of rear half 24
catches under the free edge of flange 207 on member 202 and
swings this anti-clockwise, as depicted in Figures 12 and
13, to move member 202 back to its closed position.