METHOD OF AND APPARATUS FOR PRODUCING COVERED INFUSION BAGS

Abstract: The invention is directed to an apparatus for attaching a cover to a porous bag such as a tea bag. The apparatus has means for feeding (9, 10) a strip of cover material which is cut into individual covers (13) and the apparatus has bag feeding means (12) to accurately position each bag on its respective cover, heat sealing means (15, 16) sealing a flange of the bag to the cover. The bag and cover then pass to a folding means (18) to fold the cover over the bag, and to an output channel (24) for packaging the covered bags.

Description: 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 bags. DESCRIPTION OF THE PRIOR ART. 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 teabag and cover. Also there is disclosed in Patent Application No.PCT/AU 87/00134 and the application AU73S84/87 corresponding thereto there is described a method and apparatus for producing tea bags attached to a cover in 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 fcr making s compressible infusion package in which an infusion package to which a 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 fcr winding the string about the package and cover and detachably anchoring the free end of the string to the cover. 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 4289493 describes an apparatus fcr applying an overlay to a 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 the substrate. US 3832829 describes an apparatus for banding hosiery with a band of pressure sensitive 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 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 such as coffee. ERIEF DESCRIPTION CF THE INVENTION There is provicec according to the invention an apparatus for the 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 bags on the covers, attaching means to attach a flange of the bag to the cover, creasing means to crease the cover immeec ' iately adjacent the edge of the flange of the bag anc folding means to fold the cover about the bag. BRIEF DESCRIPTION OF THE DRAWINGS. Referring to the drawings the apparatus is attached to an existing pouch maker 1 [shown in dashed lines] with the cartoning portion removed as shown by 4, the pouchmaker being positioned on a floor 2. The cover material is supplied by reel 3 which cover material is preferably polystyrene. The bags are separated at 5 and carried by suction fingers to position 1 1 where they are pushed off the fingers and they then drop into the chute 12. 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 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 [150mm] of material is delivered per machine cycle. When a printed strip is used , pulley 32 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. The strip is thus fed from roller pair 31 and 32 at constant speed ' and forms a slack loop 30 in preparation fcr a quick advance phase, begun when pressure roller .0 is ailcwed :c crop onto driven roller 9, gripping the strip and driving it through guice 36. The free end moves from the guillotine position 13 and proceeds ever the sealer/hinger pad 26. through a gap between roller pair 17/27 and steps near folding bar 16. This αuick advance occurs in nominally 25% of the cycle time. The pressure of roller 1 C 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 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 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. 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 they 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 and/or humidity of the strip is controlled and as the strip moves on a solid surface on its lower side 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 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 toleraπced height above the strip after the free end has advanced through and before the bag arrives. The creasing unit can induce 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 biade the cover material of polystyrene or ether 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 strip has stopped moving, the guillotine biade 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 heat 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 alternate position as shown in Figure 1 and in doing so it 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 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, 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 underside which is spring loaded shut, and is opened by a tab 21 protruding from triple shaft assembly 22 pushing via a red 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 pivcts 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 stacK along, there being passive restraining fingers in the channel to prevent the stack of bags falling back. The thumb is then extracted from the channel by a further motion displacing shaft 22 upwardly in the plane of the last bag. the guides preventing the bag from lifting cut of the channel. The guides 28 and the transfer arm are not in the same plane and Once the thumb is cut of the stack the transfer arm returns to pick up the next bag, a c the thumb ccened. Referring now to Figure 2 there is shown a further 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 creasing and sealing mechanisms. 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 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 creasing and heatseaiing. While the invention has been described with reference to the use of a polystyrene strip to form the covers of the tea bags, it is to be realised that other materials may be used, such as paper, coated paper or other plastics material. Heat sealing of the flange of the bag to the cover strip 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. 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 cr 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 acccrcing 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 tea bag can be supported on a cup or other drinking vessel and then be 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.

Claims: claim 10 ; other claims unchanged ( 2 pages ) ] 1. Apparatus for the attachment of a cover to a porous bag having at least one side or end flange, the bag containing an infusible substance, the said apparatus comprising means to supply a continuous feed of 5 sheet material to form the covers of the bags, cutting means to cut the sheet material into separate covers, supply means to feed the bags to the apparatus, means to feed the bags and position the bags on the covers, attaching means to attach a flange of the bag to the cover, creasing means to crease the cover immediately adjacent the edge of 10 the flange of the bag, and folding means to fold the cover about the bag; characterised in that the means to feed and position the bags on the covers includes a tray adapted to receive individual bags from the supply means, and means to move said tray and bag to position said bag adjacent said creasing and attaching means. 15 2. Apparatus as defined in claim 1 and including transfer means to transfer the bag with cover attached to a an output channel. 3. Apparatus as defined in claim 1 or claim 2 in which the means to 20 supply a continuous feed of sheet material comprises a reel containing the cover material, a drive roller feeding said cover material at constant speed to form a slack loop while feeding the strip to intermittent feed rollers to cyclically feed the strip to a guilllotine to cut the strip into the separate covers. 25 4. Apparatus as defined in claim 3 wherein the intermittent feed rollers feed the strip to remove the slack loop with a frictional force such that the intermittent feed rollers will slip when the strip becomes taut, said intermittent feed rollers comprising a driven roller and a freely rotatable 30 roller which is moved to engage and disengage from the strip in contact with the driven roller. 5. Apparatus as defined in claim 1 wherein the folding means comprises a folding bar movable through the plane of the cover strip to 35 raise the free end of the cover strip so that the cover strip is folded over the bag as the bag and the cover strip move past the folding bar. 6. Apparatus as defined in claim 5 wherein means are provided to transfer the bag and cover to an output channel said means comprising a transfer arm, a hinged thumb on the transfer arm which grasps the bag and cover and transfers it to the output channel to move the collection of bags along the output channel. 7. Apparatus as defined in claim 1 wherein the attachment means comprises a heat sealing blade to heat seal a flange of the bag to the cover material. 8. Apparatus as defined in claim 1 wherein the creasing means comprises a creasing blade, and heating means to heat the creasing blade so that the cover material is softened and slightly melted so that the thickness of the cover material at the crease is less than the thickness of the cover material. 9. Apparatus as defined in claim 8 wherein the creasing blade is serrated or toothed. 10. Apparatus for the attachment of a cover to a porous bag substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Inventors: CHRISTIE HUGH PATRICK, WALLACE ALLAN KENNETH, CHRISTIE, HUGH, PATRICK, WALLACE, ALLAN, KENNETH
Applicants: CHRISTIE HUGH PATRICK, CHRISTIE, HUGH, PATRICK
Application year: 1989
Main classification: B65B29
IPC codes: B65B29