Note: Descriptions are shown in the official language in which they were submitted.
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METHOD OF AND APPARATUS FOR PRODUCING COVERED
INFUSION BAGS
This invention relates to a method and apparatus for the production of
covered infusion bags, particularly tea 50ags.
DESCRIPTION OF THE PRIOR ART.
1 0
In Patent AU 575226 there is described an infusion bag whereby the
bag may be supported on the edge of a cup or other drinking vessel for
the infusion of the tea, and which cover can then be grasped to
squeeze the remaining liquid from the tea bag before disposal of the
15 teabag and cover.
Also there is disclosed in Patent Application No.PCT/AU 87/00134 and
the application AU73984/87 corresponding thereto there is described a
method and apparatus for producing tea bags attached to a cover in
20 which the bag is fed onto the cover for attachment thereto and folding of
the cover about the tea bag.
Patent No GB 1245359 describes a method and apparatus for making a
compressible infusion package in which an infusion package to which a
25 string is attached is attached to a cover by the string being passed
through a hole in the central crease of a cover, and a mechanism for
winding the string about the package and cover and detachably
anchoring the free end of the string to the cover.
30 US 3092242 is directed to an infusible package with a cover, the cover
being slidable on a string attached to the package and to an apparatus
for producing same.
US 4289~93 describes an apparatus for applying an overlay to a
35 substrate for example in the manufacture of book covers, by serially
wrapping the overlay around a first pair of oppositely disposed edges of
the substrate, folding the corners of the overlay into the substrate and
wrapping the overlay around the two remaining edges of th~ substrate.
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US 3832829 describes an apparatus for banding hosiery with a band of
pressure sensitiv~ adhesive on one side by manually positioning the
stockings on the band which is held by suction to a platform and
whereby the band is mechanically applied to the stockings.
It will be realised that for the attachment of the tea bag to the cover,
precise positioning of the tea bag in relation to the cover and the crease
in the cover will be required and it is an object of this invention to
provide an apparatus which will provide a means whereby a more
10 efficient and reliable attachment of the bag to the cover is attained.
While the invention is particularly directed to the production of tea bags
with a protective cover it is to be noted that the invention is not to be
limited thereto for the bag can contain any desired infusible substance
15 such as coffee.
BRIEF DESCRIPTION OF THE INVENTION
There is provided according to the invention an apparatus for the
20 attachment of a cover to a porous bag containing an infusible
substance, the apparatus comprising means to supply a continuous
sheet feed of the cover material, means to receive the bags from a
pouch making machine, cutting means to cut the sheet material into the
separate covers, means to positively feed the bags and position the
25 bags on the covers, attaching means to attach a flange of the bag to the
cover, creasing means to crease the cover immeediately adjacent the
edge of the flange of the bag and folding means to fold the cover about
the bag.
30 BRIEF DESCRIPTION OFTHE DRAWINGS.
Referring to the drawings the apparatus is attached to an existing pouch
maker 1 Eshown in dashed lines] with the cartoning portion removed as
shown by 4, the pouchmaker being positioned on a floor 2. The cover
35 material is supplied by reel 3 which cover material is preferably
polystyrene.
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The bags are separated at 5 and carried by suction fingers to position
11 where they are pushed off the fingers and they then drop into the
chut~ 12.
5 The reel of cover material is preferably free running, but a friction device
35 is preferably used to maintain an approximately uniform tension on
the strip around idler pulley 34 and up to the drive pulley 32. If more
than one track is desired slitting of the strip may be accomplished in the
region of pulley 34. If required heat may be applied to the strip by a
10 heater to reduce the residual curvature of the strip of polystyrene.
The strip of cover material is driven by drive pulley 32 which runs at
constant speed and is such that one pitch [150rnm} of material is
delivered per machine cycle. When a printed strip is used, pulley 32
15 would be driven at a variable speed controlled by a feed back loop
which maintains a set phase between the machine cycle and any
unique optically identifiable pattern detected by optical sensor 33. The
mean speed of the strip would then be one pitch per machine cycle.
20 The strip is thus fed from roiler pair 31 and 32 at constant speed and
forms a slack loop 30 in preparation for a quick advance phase, begun
when pressure roller 10 is allowed to drop onto driven roller 9, gripping
the strip and driving it through suide 36. The free end moves from the
guillotine position 13 and proceeds over the sealer/hinger pad 26,
25 through a gap between roller pair 17/27 and stops near folding bar 18.
This quick advance occurs in nominally 25% of the cycle time.
The pressure of roller 10 is set to provide sufficient friction to drive the
strip until the slack loop 30 goes taut, when the rollers 9/10 will slip until
30 roller 10 is lifted at which point the the strip stops moving and its
stopped position will depend on the timing of the lift of roller 10. It is
noted that the strip is moving at slow speed set by the feed drive roller
32 thus minimising the effect of timing variations of the roller 10 lifting.
The phase of the strip with respect to its stopping position (ie the
35 relative position of the printing and guillotining) is altered by changing
the phase set point in the loop controller for the pulley 32 drive, or by
altering the taut loop length, for example by moving passive guide 29.
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The guides 8 are wire guides intended to keep the strip as straight as
possible in order to maximise its stiffness when the slack loop 30 snaps
taut and th-sy also minimise the angle of wrap around pulley 9 to avoid
tension build up when rollers 9 and 10 are slipping.
On the delivery side of pulleys 9 and 10 there may be a risk of the free
end of the cut strip steering off path as it is pushed from behind.
However this is minimised if the temperature ancl/or humidity of the strip
is ~ontrolled and as the strip moves on a solid surface on its lower side
10 and guides are placed upstream of the heater/sealer 15 as well as
using the guiding effect of rollers 17 and 27.
The bags are pushed off the suction fingers 7 at position 11 and free fall
into the chute 12 which restrains the bags sideways and guides them
15 onto the strip just ahead of the heater/sealer/creaser units 15 and 16.
The slope of the surface on which the strip rests is such that the bag will
slide down to register against the creasing blade 16 which is positioned
within a toleranced height above the strip after the free end has
advanced through and before the bag arrives.
The creasing unit can include a blade or knife which can have a
continuous edge or have an edge which is serrated or toothed. In a
preferred form the knife or blade can be heated to assist in producing a
satisfactory hinge. Thus by heating the knife or blade the cover material
25 of polystyrene or other thermoplastic material is softened and may be
slightly melted so that the thickness of the material at this area is thinner
and so assists in providing a satisfactorily flexible hinge.
When the bag has come to rest against the creasing blade 16 and the
30 strip has stopped moving, the guillotine blade 25, heat sealer 15 and
the creasing blade 16 activate against their working surfaces 13 and 26
which may be replaceable pads of polyurethane or UHMWPE. After
sealing the hoat sealer 15 and the creasing blade 16 retract to allow the
bag to pass underneath.
During the sealing and the creasing process as described above the
folding bar 18 leaves its home position beneath the plane of the strip
and rises to its altcrnate position as shown in Figure 1 and in doing so i~
13~7~
- lifts the free end of the strip forming the cover of the tea bag. After the
sealing of the bag the cover strip the roller 17 is allowed to fall on to
roller 27, gripping the bag and driving it under the folding bar 18 so that
the first part of the cover is folded over the bag by pivoting and sliding
5 under the folding bar 18. Thus the bag and cover move into the transfer
arm 19 hinge first.
Roller 27 is continuously driven at the same peripheral speed as roller
9 to prevent the advancing strip overtaking the finished bag and cover,
10 roller 17 lifting after the bag has passed through and remains lifted until
the next cycle.
As the bag slides into the transfer arm 19, its edges are guided and rest
upon guide rails, the transfer arm 19 having a hinged thumb on its
15 underside which is spring loaded shut, and is opened by a tab 21
protruding from triple shaft assembly 22 pushing via a rod entering at
20 to allow the bag to slide in. Tab 21 is rotated to allow the thumb to
gently grasp the bag, then the arm pivots around shaft 22 carrying the
bag along the circular wire guide 28.
The bag is added at 23 to the bottom of the output channel 24, and the
thumb pushes the whole stacl< along, there being passive restraining
fingers in the channel to prevent tha stack of bags falling back. The
thumb is then extracted from the channel by a further motion displacing
25 shaft 22 upwardly in the plane of the last bag, the guides preventing the
bag from lifting out of the channel. The guides 28 and the transfer arm
are not in the same plane and once the thumb is out of the stack the
transfer arm returns to pick up the next bag, and the thumb opened.
30 Referring now to Figure 2 there is shown a furlher embodiment
illustrating an alternate means for accurately positioning the bag for
attachment to the cover strip. The bag 37 as shown is held by the
suction finger 7 and is dropped onto tray 38, the tray 38 carrying the
bag 37 to position 38(a) where the bag 37(a) is positioned adjacent the
35 creasing and sealing mechanisms.
~Z,
In order to move the tray 37 to transfer the bag 38 the tray 37 is
supported by a pair of links 39 and 40 hinged to the tray 37 forming a
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four bar linkage. Link 39 is pivoted at 41 to a portion of the frame while
link 40 is pivoted at 42, whereby it will be seen that the tray 38 will
transfer the bag from the ~suction finger to be positioned on the cover
strip for cr0asing and heatsealing.
While the invention has been described with ref~rence to the use of a
polystyrene strip to form the covers of the tea bags, it is to be realised
that other ~naterials may be used, such as paper, coated paper or other
plastics material. Heat seaiing of the flange o~ the bag to the cover strip
10 has been particularly described but other forms of attachment can be
used, such as stapling, stitching, and glueing by the application of a
pressure sensitive adhesive or by the application of a liquid or paste or
other adhesive which may be dried by heat, ultra violet light, or
incorporate a solvent.
1 ~;
Also while the invention has described the bags being positioned on
the cover strip in a longitudinal direction the bags may be positioned
across the cover strips, and the creasing and heat sealing may thus be
performed by rotary members.
The bags and covers may be stacked vertical in the output channel or
may be stacked in an overlapping manner as is known as Penny
Stacking, so that the bags can be removed for packaging in boxes or
other containers.
Hence it will be seen that there is provided according to this invention a
simple and economical attachment to a pouch making machine
whereby the pouches or tea bags are attached to a cover so that the ~ea
bag can be supported on a cup or other drinking vessel and then be
30 easily removed from the cup by squeezing to remove the surplus liquid
therefrom and then for ease of disposal. The machine can be a single
track machine or can be a multiple track machine so that a plurality of
bags are provided with covers at the same time.
