GB2314312A - Producing joined pairs of infuser bags - Google Patents

Description

2314312 improvement to a machine for the manufacture of f ilter bags

containing infusionable substances, and a relative method of fashioning such bags The present invention relates to an improvement in a machine for the automated manufacture of filter bags filled with infusionable substances, for example tea, camomile flowers and other similar products, also to a relative method of fashioning such bags.

The adoption of filter bags as a means of preparing individual beverages by infusion is now generally established the world over, thanks chiefly to their simplicity and ease of use.

In the light of this increased popularity, attempts have been made to 'maximize the comparative appeal of different bags, especially by those whose job is to market the product, achieving improvements in retention of the particulate substance, in the rate of interaction with liquids during the time allowed for infusion, in shelf life, ease of packaging, and so forth Current marketing strategies have led manufacturers in certain countries to adopt the circular style of 2 bag (without the thread and finger tab label more familiar in those countries hitherto), which tends not to be wrapped individually and is packaged typically in boxes, often two or more rows deep. 5 Filter bags of this general type, that is to say the one-cup bag consisting in a single sachet, are fashioned generally in pairs two abreast from two strips of plain filter paper matched and bonded together by a succession of circular seals to form 10 single envelopes, each containing a measure of the infusionable substance. In their current form, automatic machines of the type used to manufacture the product in question comprise a series of stations arranged along a 15 substantially horizontal feed path, by which single bags of the infusionable substance are fashioned and made ready for packaging into boxes. At a decoil station located first in sequence along the feed path, a continuous strip of filter paper 20 is drawn from a roll and divided longitudinally into two halves; the first half is directed beneath a station from which measures of the infusionable substance are dispensed in pairs, disposed two abreast, whilst the second half is made to by-pass 25 the dispensing station and then assume a position 3 over the first half, covering the paired measures of the substance already deposited on the paper.

The station next in sequence, or rather positioned following the dispenser along the horizontal path, comprises means by which the two joined halves are heat sealed in such a way as to form a pair of circular envelopes each containing a measure of the infusionable substance; next after the heat seal means are means by which the bag is cut to its final circular shape. Both the heat seal means and cutting means will consist typically in a pair of rollers contrarotating about respective horizontal axes and positioned one directly above the other, the former shaped in such a way as to generate a succession of circular envelopes, each coinciding with a respective bag, and the latter in such a way as to-effect a corresponding succession of circular cuts.

The continuous strip of envelopes fashioned in this manner is advanced along a conveying surface toward a station at which the single bags are separated from the surrounding scrap material; thereafter, the bags are stacked and packaged ultimately, at respective stations, giving place to an end product in which the single bags are ordered in rows placed 4 alongside but completely separate one from another. The policy now being adopted by manufacturers, with both sales and production in mind, is to package the end-product as a pair of filter bags joined 5 together by a small interconnecting web of filter paper left intentionally in place, in such a way that the bags can be used either singly or in pairs by the consumer; if singly, the bags are separated one from another simply by pulling apart to break 10 the web. Given the diminutive size of the web, a separation is effected without in any way affecting the integrity of the bags themselves. The solution of manufacturing filter bags in joined pairs has also been found advantageous in terms of obtaining 15 greater compactness in the finished pack. The object of the present invention is to bring about-an improvement in a machine for the automatic manufacture of filter bags in joined pairs, such as will allow of maintaining a high output of bags per 20 unit of time and at the same time assure superior quality of the end product, without the need for extensive design changes affecting either the machine overall or its existing single stations. The stated object is duly realized in an improved 25 machine as characterized in the appended claims.

The invention will now be described in detail, by way of example, with the aid of the accompanying drawings, in which: fig 1 illustrates part of an improved machine for 5 the manufacture of filter bags according to the present invention, seen schematically in a side elevation with certain parts cut away and certain in section; -fig 2 illustrates a part of the machine in fig 1, 10 in particular a cutting station and a station at which the bags are diverted from one path onto another, seen in perspective and with certain parts omitted better to reveal others; fig 3 illustrates an enlarged detail of fig 2, in 15 particular a clearance element associated with the cutting station, viewed in a side elevation; fig 4 illustrates a detail of the cutting station in the improved machine according to the invention, and in particular, half the circumference of a 20 cutting roller developed in a horizontal plane; -fig 5 is the section through V-V in fig 2; -figs 6 and 7 illustrate an ejector forming part of the machine disclosed, seen respectively in plan from above and in a section through VII-VII fig 6; 25 -fig 8 illustrates a fragment of a suction port 6 forming part of the machine disclosed, viewed in a side elevation; -fig 9 affords a fragmentary perspective view of a continuous strip of filter paper, indicating a pair of filter bags fashioned by the machine disclosed, and an area consisting of scrap material only; -figs 10 to 13 illustrate a succession of operating steps performed by the machine disclosed, in which the bags are diverted away from the continuous strip of filter paper; -fig 14 illustrates the step of fig 13 in a further perspective view, with certain parts omitted better to reveal others; -fig 15 shows a detail of fig 2, and more precisely a supporting plate associated with the diverting station, viewed in plan from above; -fig 16 is an enlarged detail of fig 4, seen in plan from above and illustrating a portion of a cutting edge afforded by a roller forming part of the machine disclosed; -fig 17 is the section through XVII-XVII in fig 16.

With reference to the accompanying drawings, and to fig 9 in particular, the present invention relates to a machine for the manufacture of filter bags 1 containing infusionable substances (tea, camomile 7 flowers, etc.), consisting in two matched circular portions la and 1b of strip f ilter paper, each such bag containing a measure 2 of the aforementioned infusionable product.

observing fig 1, parts of the machine pertinent to the present disclosure include a horizontal feed path A, and located on the path, a station 3 at which two measures 2 of the infusionable substance are dispensed one alongside the other by metering means 4 (not shown in their entirety) onto a first strip N1 of filter paper advancing horizontally along the feed path.

At a given point along the feed path A beyond the dispensing station 3, a second strip N2 of filter paper is laid over the first strip N1, whereupon both strips N1 and N2 are directed immediately into a heat seal station 5 and united in such a way as to generate a continuous strip lc appearing as a succession of closed sachets or envelopes advancing in pairs two abreast, each containing a relative measure 2 of the infusionable substance. The heat seal station 5 will consist typically in a pair of heated first rollers Sa and 5b disposed one above the other, set in contrarotation about respective horizontal axes and affording pluralities of first 8 recesses denoted 5c; the recesses Sc are arranged in pairs and shaped in such a way as to establish the geometry of the pairs of envelopes which, set at a suitable distance one from the other and heat sealed, are carried forward horizontally along the feed path A toward a cutting station 6.

The cutting station 6 comprises a pair of second rollers 7 and 8 disposed one above the other and contrarotating about relative horizontal axes, of which the cylindrical faces afford pluralities of second recesses 9 and 10, arranged likewise in pairs. Each of the second recesses 9 and 10 is surrounded by a relative cutter 11 such as will pierce the periphery of the corresponding bag 1 and enable its separation from the continuous strip lc.

As discernible from figs 1, 2, 4 and 5, one of the two rollers 7 and 8, and more exactly the roller 7 positioned uppermost (in the example illustrated) in relation to the advancing strip lc, is equipped with pairs of such cutters 11 arranged one beside another, each exhibiting a gap 17 positioned to coincide with a portion of the relative second recess 9 and 10 adjoining the recess 10 and 9 alongside: in practice, these same gaps 17 create pairs of terminated cutting edges denoted 11a and 9 llb (see also figs 16 and 17), which are merged at points substantially coinciding with the relative gap 17 in such a manner as to leave an uncut area of the strip lc that serves to establish a web 16 5 joining the two bags 1 of each pair. In other words, the cutters 11 associated with each pair of second recesses 9 and 10 are joined without any break in continuity around the periphery of the two recesses 9 and 10, i.e. considered as a pair, 10 inasmuch as the cutting edges 11a and 11b are both mutually adjacent and joined to one another, and the gap 17 is located at the point of tangential proximity between the circumferences described by the paired cutters 11; the resulting configuration 15 matches the final shape of the pair of bags 1 cut from the strip and may be referred to conveniently as a Yfigure of eight". 18 denotes one of a plurality of clearance elements fitted to the top roller 7 of the cutting station 6 20 and equal in number to the pairs of recesses 9 and 10, which occupy positions on the cylindrical face of the roller 7 coinciding with areas unaffected by the cutting action applied to the bags 1. In effect the clearance elements 18 are located on either 25 side of each gap 17 and designed to generate a force directed away from the roller 7 on completion of the cutting stroke, in such a way that the inner area of the continuous strip lc nearest the gap 17 is kept permanently horizontal and within the same plane as that occupied by the cut bags 1.

As discernible also in fig 3, the single clearance element 18 might be composed advantageously of two slender arcuate and flexible tongues 19 and 20, which follow the sectional profile of the roller 7 at least in part. The two tongues 19 and 20 are mutually opposed in such a way as to service two different gaps 17 relative to respective pairs of recesses 9 and 10; in effect, the two tongues 19 and 20 are united at the centre by a base 21 fixed stably to the roller 7, each extending and tapering toward the end remote from the base 21, with each tapered extremity located in close proximity to the respective gap 17 of a relative pair of recesses 9 and 10.

To maximize the radial force obtainable from the tongues 19 and 20 (indicated by the arrow denoted F in fig 5), each tongue 19 and 20 extends away from the central base 21 in such a way that the tapered end lies outside the circumferential compass of the roller 7 when the tongue is at rest, i.e. when not depressed between the two contrarotating rollers 7 and 8. As indicated clearly in f ig 5, there are four such clearance elements 18 fitted to the cutting roller 5 7 described and illustrated, of which the bases 21 are equispaced circumferentially, distanced by an angle a of 450 from each gap 17 preceding and following in the direction of rotation. Still observing figs 2 and 4, the top roller 7 is 10 equipped with a pair of continuous circumferential spacer rings 30 rolling in contact with the bottom roller 8, located on either side of the cutters 11 and outside the area occupied by the continuous strip lc of bags 1. The function of the rings 30 is 15 to attenuate the pinch pressure generated between the two rollers 7 and 8 (needed in order to ensure correct timing of the cut), which otherwise would be concentrated entirely on the cutters 11 and result in rapid wear of the relative cutting edges, 20 especially the areas adjoining the gaps 17. Referring again to fig 1, the cutting station -.6 is followed by a station 13 at which the bags 1 are separated from the residual or scrap part 12 of the continuous strip lc through the agency of relative 25 means 14 such as will divert the bags 1 toward a 12 station 15 where they are stacked and boxed (this latter station 15 is indicated only in part, being conventional in embodiment and not strictly central to the invention).

As discernible from figs 1 and 2, the separating station 13 comprises a single ejector element 22 which constitutes the diverting means 14 mentioned above and is designed to redirect the two bags 1 of each pair together along path perpendicular to the feed path A followed by the continuous strip lc, also a horizontal plate 23 on which the continuous strip lc of bags 1 is supported and advanced.

More exactly, the plate 23 affords a passage 24 (shown in figs 2 and 15) positioned to_coincide with the point at which the bags 1 are separated from the scrap 12 by the ejector 22, and shaped in such a way as to match the configuration of the pair of bags 1 in part. In effect, the passage 24 presents substantially a figure of eight outline, with two circular areas 24a and 24b to admit the bags 1, and lies between two central areas of the plate 23 complementary to the circular areas: the one denoted 24c, located to the side on which the bags 1 are taken up from the cutting station 6 and matching the tapered outline of the central portion 13 of scrap 12 left when the bags 1 are cut, the other denoted 24d, remote from the cutting station 6, and defined by a straight line interconnecting the two circular zones 24a and 24b. 5 The ejector element 22, illustrated in figs 6 and 7, comprises a pair of push rods 25 interconnected by a rigid central cross member 26. The ejector 22 is capable of movement (see also figs 10 to 13) between a raised, non- operating position, in which 10 the push rods 25 are distanced from the continuous strip lc, and a lowered operating position (see arrow F1 in fig 10) in which the push rods 25 make contact with the two bags 1 of a pair lying side by side ready to be diverted, and the cross member 26 15 makes contact with the web 16. The downward travel of the ejector 22 will be seen to extend beyond the continuous strip lc of bags, the reason being that the cross member 26 of the ejector 22 affords a horizontal lip 27 of which the 20 function is to lift a portion of scrap 12 detached from the web 16 and left on the relative area 24c of the plate 23 when the ejector 22 returns upwards to regain the raised non-operating position (the reason for which will be explained in due course). 25 observing figs 1, 8 and 14, it will be seen that 14 the separating station 13 is followed along the feed path A by scrap collection means denoted 36, comprising a suction port 28 into which the residual continuous strip lc of scrap material 12 5 is drawn by a negative pressure generated upstream of the port 28. 29 denotes a restraint surmounting the suction port 28 and positioned to intercept the advancing scrap material 12; more exactly, the restraint 29 is 10 designed to engage a portion 12c of the scrap generated adjacent to the web 16 uniting the pair of bags 1, being substantially that portion which is lif ted by the lip 27 during the upward return stroke of the ejector 22. is The sequence of steps whereby pairs of bags 1 are fashioned using a machine structured in the manner described thus far will be readily discernible and can now be summarized, assuming the two strips N1 and N2 of filter paper.to have been heat sealed 20 together with paired measures 2 of an infusionable substance between them, and assembled thus into a continuous strip lc that exhibits pairs of circular envelopes advancing two abreast and spaced apart in ordered succession as the strip lc moves along the 25 feed path A.

As the continuous strip lc of filter paper advances through the cutting station 6, the rollers make a succession of single peripheral incisions ST each encompassing a pair of bags 1 united by a relative 5 web 16 of filter paper at the point where the two bags lie mutually adjacent: the incision is made by the aforementioned cutters 11 of which the profile, to reiterate, presents substantially no break in continuity. 10 After the cut, the strip lc advances horizontally along the feed path A and enters the separating station 13, where the two bags 1 of the pair are detached simultaneously from the remainder of the continuous strip lc of filter paper by the action 15 of the ejector 22 described above, which engages both bags 1 and the interconnecting web 16 at one and the same time. As illustrated in figs 10 to 14, the separation of the pairs of bags 1 from the strip is brought about 20 as the ejector 22 descends (see fig 11, arrow F2) and enters into contact ultimately with the bags 1 and the interconnecting web 16, which are directed downwards and thus diverted toward the stacking station 15; the ejector 22 continues its downward 25 movement beyond the plane occupied by the advancing 16 continuous strip lc.

During the upward return movement of the ejector 22 (see fig 12, arrow F3), the tapered portion 12c of scrap 12 lying immediately adjacent will be lifted by the lip 27 (see fig 12, arrow F4).

As the continuous strip lc advances toward the collection means 36, a further pair of bags 1 will be separated by the ejector 22 at the same time as the tapered portion 12c, now loose and disposed essentially vertical in relation to the remainder of the strip lc (as indicated in figs 13 and 14) approaches the suction port 28 and is intercepted by the restraint 29. With the separation of another pair of bags 1 from the strip lc, a further tapered is portion 12c' is generated which combines together with the first portion 12c and with two transverse portions 12d and 12e to define an area of the scrap material 12 occupying the middle of the strip lc that appears substantially as a four pointed star.

With the second tapered portion 12c, now freed and drawn naturally toward the suction port 28, the entire star is made to pivot on the two transverse portions 12d and 12e (see fig 14, arrow F5), due to the resistance offered by the restraint 29 to the first portion 12c, which is then also drawn into 17 the port 28.

The object stated at the outset is thus realized in an improved machine according to the invention, which will turn out filters bags 1 in pairs, joined by a relative web 16, to a high level of quality and at high speed.

With the shape of the bags 1 generated in a single cutting pass, the peripheral incision made around the recesses 9 and 10 is guaranteed to be precise.

The continuous strip lc is kept on a horizontal course thanks to the clearance elements 18 located between the different pairs of recesses 9 and 10, and the scrap 12 thus prevented from catching and crumpling on the cutting roller 7.

The combination of the ejector 22, the plate 23 and the suction port 28 ensures a correct and exact separation of the pair of bags 1 from the strip lc as well as a dependable removal of the advancing scrap material 12 which, in view of its particular geometry, could otherwise prove difficult to direct cleanly into the suction port 28.

Among the many alternative options available when carrying the improvement into effect, the clearance elements 18 might be embodied, by way of example, as radial pistons fitted to the roller at points p 18 adjacent to each of the gaps between the pairs of recesses, or as jets of air issuing from holes let into the surface of the roller at points coinciding with the gaps.

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Claims (14)

1. Claims

   An improvement to a machine for the manufacture of filter bags containing infusionable substances, each defined by two matched circular portions of filter paper each enclosing a measure of the substance, in particular a machine with stations arranged along a substantially horizontal feed path, typically including: - a station at which at least two measures of the substance are dispensed simultaneously two abreast by relative metering means onto a first strip of filter paper, advancing horizontally, over which a second strip of filter paper is laid at a point beyond the dispensing station; - a heat seal station into which the two strips are directed as one and united in such a way as to generate a continuous strip exhibiting pairs of envelopes spaced apart and containing respective measures of the substance one alongside another; - a station at which the envelopes are cut, comprising a pair of rollers contrarotating about respective horizontal axes, arranged one above the other, of which the cylindrical surfaces each present a plurality of pairs of recesses disposed side by side, each surrounded by a relative peripheral cutter designed to pierce the outline of the relative bag and thus allow its removal from the strip; - a station at which the bags are separated from the residual portion or scrap material of the strip through the agency of relative means designed to divert the bags toward a stacking and packaging station; - means for collection of the scrap material, located at a point beyond the separating station along the feed path characterized - in that at least one of the contrarotating rollers is equipped with cutters arranged in pairs side by side, each presenting a gap located at a point where the recesses lie mutually adjacent and defining a pair of terminated cutting edges of which the corresponding terminations are merged together at the gap in such a way as to leave an area untouched by the cut and designed to create a web uniting the pair of bags.
2. h 21 2) An improvement as claim 1, wherein the cutting edges are disposed alongside one another and the gap is created at the point of tangential proximity between the circumferences described by the relative pair of cutters.
3. 3) An improvement as in claim 1, wherein each of the pair of recesses afforded by the at least one roller is furnished with a clearance element occupying an area of the circumferential face untouched by the cut, effectively on either side of the gap, and designed to produce an outwardly directed radial action at the end of the cutting stroke effected by the rollers such as will ensure that at least a loose inner part of the strip generated by the cut and lying nearest to the gap is maintained substantially in a horizontal plane.
4. 4) An improvement as claim 3, wherein the clearance element is elastically deformable, adapted to the sectional profile of the roller at least in part, and composed of two slender arcuate and flexible tongues mutually opposed and united centrally by a base fixed to the at least one roller, extending 22 and tapering toward the end remote from the base in such a way that each tapered end is located in close proximity to the respective gap of a relative pair of recesses.
5. 5) An improvement as in claim 3, wherein each tongue extends from the central base in such a way that the tapered end remote from the base lies outside the circumferential compass of the roller when the tongue is in an at-rest position.
6. 6) An improvement as in claim 3, wherein the base of the clearance element is positioned angularly equidistant and separated by a predetermined angle from the gaps preceding and following in rotation.
7. 7) An improvement as in claim 1, wherein at least one of the cutting rollers affords a pair of continuous circumferential spacer rings located in contact with the contrarotating roller, disposed on either side of the cutters and outside the area occupied by the continuous strip of bags.
8. 8) An improvement as in claim 1, wherein the separating station comprises a single ejector 23 element coinciding with the diverting means and designed to redirect the two bags of each pair at one and the same time along a path perpendicular to the feed path followed by the continuous strip, also a horizontal plate on which the continuous strip of bags is supported and advanced, affording a passage positioned to coincide with the point at which the bags are separated by the ejector from the scrap material, and shaped in such a way as to match the peripheral outline of the pair of bags at least in part.
9. An improvement as in claim 1, wherein the separating station comprises a single ejector element coinciding with the diverting means and designed to redirect the two bags of each pair at one and the same time along path perpendicular to the feed path followed by the continuous strip, also a horizontal plate on which the continuous strip of bags is supported and advanced, affording a passage positioned to coincide with the point at which the bags are separated by the ejector from the scrap material, and shaped in such a way as to match the peripheral outline of the pair of bags at least in part, the ejector element comprising a 24 pair of push rods interconnected by a rigid central cross member and capable thus of movement between a raised non-operating position, in which the push rods are distanced from the continuous strip, and a lowered operating position in which the push rods impinge simultaneously on the two bags of the pair and the cross member impinges on the web, having passed through and beyond the continuous strip.
10. 10) An improvement as in claim 9, wherein the ejector exhibits a horizontal lip associated with the rigid cross member and designed to lift at least the portion of scrap detached from the web uniting the bags as the push rods return to the non-operating position.
11. 11) An improvement as in claim 1, applied to collection means comprising a suction port located following the separating station along the feed path and designed to draw in the residual continuous strip of scrap material horizontally, wherein the suction port affords a restraint positioned to intercept the advancing scrap material, surmounting the port in such a way as to engage a portion of the scrap that lies adjacent to the web uniting the two bags of a pair and is loose in relation to the remainder of the continuous strip.
12. 12) A method of manufacturing a pair of filter bags filled with an infusionable substance, consisting in two envelopes disposed one alongside another, each containing a corresponding measure of the substance, characterized in that it comprises the steps of: a) piercing a continuous strip of filter paper in such a way as to produce a single peripheral incision encompassing a pair of bags interconnected at mutually adjacent points by a web of filter paper; b) separating the two bags of the pair as one from the remainder of the continuous strip by a direct action applied simultaneously to both bags, and to the web uniting the bags.
13. 13) A method as in claim 12 wherein step a) is effected by means of a cutter exhibiting an outline that presents no break in continuity.
14. 14) An improvement as in claims 1 to 11, and a method as in claims 12 and 13, described and illustrated - 1. f. 26 with reference to the figures of the accompanying drawings and intended for the stated objects.