WO2025202840A1 - Packaging machine for making filter bags with infusion products - Google Patents

Abstract

Described is a station for weighing boxes (10) containing a respective group of filter bags with infusion products inserted in a packaging machine (100) comprising a channel (12) for transporting the boxes (10) containing the respective groups of filter bags, along a feed direction (A); a weighing unit (13) configured for weighing each box (10) containing the respective group of filter bags a supporting surface (14) positioned downstream of the transport channel (12) relative to the feed direction (A) and at a height lower than that of the transport channel (12), and a pusher device (15) slidably movable on the supporting surface (12), parallel to the feed direction (A), and configured for being moved between a withdrawn position in which it is positioned behind a rear wall (10a) of the box (10), which has fallen from the transport channel (12) on the supporting surface (14), and a forward position in which it pushes the box (10) fallen towards the weighing unit (13).

Description

DESCRIPTION

PACKAGING MACHINE FOR MAKING FILTER BAGS WITH INFUSION PRODUCTS

Technical field

The invention relates to a packaging machine for making filter bags with infusion products (such as tea, coffee, camomile and the like).

Background art

Prior art packaging machines comprise a plurality of processing stations at which respective steps are performed which contribute to making filter bags with infusion products.

These filter bags with infusion products are usually made starting from pieces of filter material, which is folded in such a way as to enclose, inside, one or two doses of a substance designed to be infused.

The filter bags are also associated with a thread which allows the filter bag to be connected with a gripping tag, making a product ready for being grouped together and suitably stacked at an outfeed zone of the machine, which is usually followed by a station for final packaging of the infusion products inside suitable containers or boxes.

Before the stacking the filter bags a packaging of each single filter bag can also be carried out using a sheet of overwrapping material suitably folded on the bag to define the typical envelope-like package containing the filter bag.

The machines for making and packaging these filter bags comprise:

- a station for feeding a web of filter paper along a feed surface;

- a station for feeding doses of product on the web of filter paper at predetermined distances;

- a station designed to close the web on itself, wrap the doses of product and, subsequently, longitudinally join the web;

- a station for cutting pieces of filter paper with a dose of product inside; - a carousel equipped with radially protruding grippers, positioned beneath the closing and cutting station and configured to receive individual pieces of filter paper; the carousel, moved stepwise about a horizontal axis, moves each piece of filter paper in the proximity of stations arranged one after another to associate to the piece of filter paper a thread, suitably wrapped around the piece of filter paper, and a tag in turn associated with the thread; If necessary, there may also be a station for applying an overwrapping material to the filter bag thus obtained along the path of the carousel;

Moreover, the carousel transfers the filter bag thus formed to a station for preparing and packaging groups of filter bags comprising at least one unit for stacking and transferring the filter bags stacked in packages suitably formed in a station having units for forming and moving the empty packages towards a position for receiving groups of filter bags.

At this point, each package formed is positioned on a channel for expulsion from the machine.

Along this channel each package is fed to reach a weighing station for checking the correct weight of the groups of filter bags housed inside the package.

Currently, the weighing stations have systems for weighing these packages which can be of three different types.

Two of these types use the continuous “pack” outfeed of the packages from the filling station which determines a step-like feed movement of the individual packages along the expulsion channel thanks to the mutual pushing of the packages formed.

A first weighing solution which uses this forward movement (in a stepwise fashion) comprises the use of two different movement units, the first unit for moving the box above the weighing scale and a second unit for returning the box on the expulsion channel or, in the case of an incorrect weight detected, for expelling the box from the channel.

A second weighing solution which uses this feeding has three motor-driven belts inserted in succession along the expulsion channel, the first and the third belts have a greater feed speed to allow at least a temporary spacing of the boxes arriving and leaving and allow the central belt, equipped with a system for measuring the weight and with a reduced speed, to perform the weighing of the package in transit. Also in this case, if a weight which does not fall within the programmed range is detected, close to the second or third belt there are means for expelling the package from the expulsion channel.

These two weighing system solutions have drawbacks.

In both the solutions there are additional systems, lateral in the first solution or along the expulsion channel in the second solution, which result in an increase in the space used on the machine, in particular at the rear of the machine, with obvious negative repercussions both on the overall dimensions and the overall cost of the machine.

The third known type of weighing uses a system for moving the individual packages by means of a relative unit formed by a supporting surface for the incoming packages combined with a system comprising two parallel arms equipped with elements (adjustable) for retaining and pushing the packages.

The two arms slide in both directions to allow the picking up of the individual packs inside four positioning elements, their stepwise feeding towards a weighing scale plate; when the package is released onto the weighing scale plate, the arms are configured to recollect the package after its weight has been obtained.

This solution has several drawbacks:

- the combined presence of the surface, carriage and group of retaining elements requires large operating spaces along the end part of the machine with a consequent increase in the overall dimensions of the machine and the overall costs of the system;

- the size changes of the packages must be performed manually by an operator on all the retaining elements with a consequent slowing down of the machine productivity; - the need to release and recover the package on/from the weighing scale increases the settlement times necessary to obtain a precise weighing of the package; this factor also increases the total times of the weighing operation.

Disclosure of the Invention

The aim of the invention is to provide a weighing station and a packaging machine for making filter bags with infusion products with this weighing station which overcomes the above-mentioned drawbacks of the prior art.

In particular, the aim of the invention is to provide a packaging machine for making filter bags with infusion products which is able to carry out a weighing of each package in a simple and inexpensive manner.

A further aim of the invention is to provide a packaging machine for making filter bags with infusion products equipped with a weighing system with a reduced size, but maintaining a fast, precise weighing and with the possibility of a fast and easy changeover of the sizes of the packages in arrival.

The technical purpose indicated and the aims specified are substantially achieved by a packaging machine for making filter bags with infusion products comprising the technical features described in one or more of the accompanying claims.

Brief description of the drawings

Further features of the invention and its advantages are more apparent in the non-limiting description below, with reference to a preferred but nonexclusive embodiment of a packaging machine, as illustrated in the accompanying drawings, in which:

- Figure 1 is a schematic side view, with some parts cut away to better illustrate others, of a machine for making filter bags with infusion products according to this invention;

- Figure 2 is a perspective view, with some parts cut away to better illustrate others, of a weighing station of the packaging machine of Figure 1 in a first operating position;

- Figure 3 is a schematic side view of an enlarged detail of Figure 2;

- Figure 4 is a perspective view, with some parts cut away to better illustrate others, of the weighing station of the packaging machine of Figure 1 in a second operating position;

- Figure 5 is a perspective view, with some parts cut away to better illustrate others, of the weighing station of the packaging machine of Figure 1 in a third operating position;

- Figure 6 is a perspective view, with some parts cut away to better illustrate others, of the weighing station of the packaging machine of Figure 1 in a fourth operating position;

- Figure 7 is a schematic side view of an enlarged detail of Figure 6.

Detailed description of preferred embodiments of the invention

With reference to the accompanying drawings, in particular Figure 1 , a weighing station and the packaging machine according to the invention, the machine labelled 100 in its entirety, are used for making filter bags with infusion products, in particular, but without limiting the scope of the invention, tea, coffee, camomile and the like.

As illustrated, the packaging machine 100 comprises a station 1 for feeding a web 2 of filter paper.

In particular, the feed station 1 comprises a reel for feeding a web of filter paper advancing along a feed direction.

The packaging machine 100 also comprises a station 3 for dosing product on the web 2 of filter paper at predetermined distances.

In particular, the dosing station 3 comprises a rotating drum configured to form the doses and place them on the web 2 of filter paper; above the drum there is a hopper for feeding the product to the drum.

The packaging machine 100 also comprises a station 4 configured for closing the web 2 wrapping the doses of products (with longitudinal joining of the web).

Moreover, the packaging machine 100 comprises a cutting station 5 for separating the filter bags with the product inside them.

The closing station 4 and the cutting station 5 are illustrated with a single block in Figure 1 .

Again as illustrated, the packaging machine 100 comprises a carousel 6 equipped with radially protruding grippers 7 positioned downstream of the cutting station 5.

The carousel 6 is configured for receiving the separate bags and is movable about a horizontal axis for carrying the individual bags close to stations arranged one after another for associating with the bag a thread, a tag in turn associated with the thread and, if necessary, a piece of paper for the over-wrapping of the bag.

Figure 1 schematically illustrates the station 19 for feeding the thread, the station 20 for feeding the tags and the station 21 for feeding the piece of paper for the overwrapping.

As illustrated, the packaging machine 100 comprises a station 8 for stacking filter bags released by the carousel 6 configured to form groups of stacked filter bags.

The stacking station 8 comprises a tubular channel 8a for stacking the bags and an underlying area which can be engaged by a head 8b for handling the stack of bags formed and configured to rotate from a position for picking up (not illustrated) a group of stacked bags to a position for releasing the group of stacked bags (illustrated in Figure 1 ).

As illustrated, the packaging machine 100 comprises a station 9 for forming boxes 10 configured to form and move empty boxes 10 towards a position for receiving the groups of stacked filter bags (carried by the handling head 8b).

The station 9 (illustrated as a block in Figure 1 ) feeds individual blanks to a forming device 9a configured to three-dimensionally form the empty box 10. Under the forming device 9a a plate 9b moves for gripping the bottom of the empty box 10 and configured to move the empty box 10 towards the position for receiving the group of stacked filter bags so as to fill the box 10 with the group of filter bags.

The packaging machine 100 comprises a weighing station 11 comprising a channel 12 for transporting the boxes 10 containing the respective groups of filter bags arriving from the forming station 9 and positioned along a feed direction A.

The weighing station 1 1 is equipped with a weighing unit 13 configured for weighing each box 10 containing the respective group of filter bags.

Again as illustrated (see also Figures 2 to 7), the weighing station 1 1 comprises a supporting surface 14 positioned downstream of the transport channel 12 with respect to the feed direction A and at a height less than that of the transport channel 12.

The weighing station 1 1 also comprises a pusher device 15 slidably movable on the supporting surface 14 parallel with the feed direction A and configured to be moved between a withdrawn position (Figures 2 and 3) in which it is positioned behind a rear wall 10a of the box 10, the box 10 falling from the transport channel 12 on the supporting surface 14, and a forward position in which the pusher device 15 pushes the box 10 falling towards the weighing unit 13 (Figure 4).

It should be noted that the pusher device 15 is positioned close to the channel 12 when the pusher device 15 is in the withdrawn position (Figure 3).

The weighing unit 13 is positioned flush with respect to the supporting surface 14, that is, coplanar with respect to the supporting surface 14.

In light of this, the weighing unit 13 comprises a supporting plate 13a for the boxes 10 to be weighed connected to a plurality of heads 13b for measuring the weight connected to a device 13c for calculating the weight.

It should be noted that the pusher device 15 is configured to push the weighed box 10 out of the weighing unit 13, along the feed direction A (see Figure 5), before returning to the above-mentioned withdrawn position. Moreover, the pusher device 15 is configured to move temporarily away from the box 10 once the latter is positioned on the weighing unit 13 to allow a correct weighing.

In light of this, the pusher device 15 comprises a rod 16 which is positioned perpendicularly relative to the feed direction A.

The weighing station 1 1 also comprises means 17 for guiding the pusher device 15 configured for moving the pusher device 15 in phase synchronization with the feeding of the boxes 10 moved along the transport channel 12, so as to allow the pusher device 15 to slide under the box 10 as it falls onto the supporting surface 14 (see Figures 6 and 7).

It should be noted that the pusher device 15 is sized in such a way that it does not exceed the height of the transport channel 12 when the pusher device 15 is in the withdrawn position (this prevents interference by the rod when the box falls from the transport channel 12).

The movement means 17 comprise a linear actuator 17a, positioned laterally and parallel to the supporting surface 14, to which the rod 16 is connected.

Again as illustrated, the weighing station 1 1 comprises ejection means 18 configured to eject the box 10 transversely to the feed direction A when the weight of the box 10, measured by the weighing unit 13, falls outside preset values.

In light of this, the ejection means 18 comprise, by way of a non-limiting example, a pair of nozzles 18a positioned above the weighing unit 13 and perpendicular to the feed direction A.

These nozzles 18a are fed with a fluid and are configured to direct a flow of air towards a side wall of the box 10 located on the weighing unit 13 in such a way as to push and drop laterally the box 10 into a container 18b for collecting rejected boxes 10.

According to an alternative not illustrated, the ejection means 18 may be mechanical actuators for pushing on the rejected box, without thereby limiting the scope of this invention. As illustrated, the weighing station comprises a gripping and pushing and head 19 for picking up and pushing the boxes 10 filled with the groups of filter bags.

In light of this, the gripping and pushing head 19 is configured to push the box 10 along the transport channel 12 to obtain a line for accumulating boxes 10 advancing along the feed direction A.

As illustrated in Figure 1 , the gripping head 19 comprises a frame 19a supporting a pushing head 19b equipped with a pair of lower horizontal rods 19c supporting part of the bottom and a pair of upper heads 19d for contact with the upper edge of the box 10 and folding a flap of the box 10.

The rods 19c and the heads 19d are coupled in a snap-on fashion on the edges of the rear wall 10a of the box 10.

The frame 19a of the head 19 is connected to movement means 22 configured to move the head 19 from a withdrawn position for intercepting the box 10 with the group of filter bags to an advanced position for inserting the box 10 on the transport channel 12 with relative feeding of the boxes 10 present in the transport channel 12 along the feed direction A.

The head 19 has a pushing stroke as a function of the size of the box size present on the packaging machine.

It should also be noted that along the transport channel 19 there are a plurality of folding and closing devices 23, 24 configured to fold and close with tucking the lid of the box 10 as it moves along the transport channel 12. The invention also provides a packaging machine 100 for making filter bags with infusion products having a weighing station 11 as described above.

This invention also provides a method for weighing boxes 10 containing a respective group of filter bags with infusion products.

The method comprises the steps of:

- conveying the boxes 10 containing the respective groups of filter bags through a transport channel 12 along a feed direction A,

- weighing each box 10 containing the respective groups of filter bags using a weighing unit 13. The weighing step comprises the following sub-steps:

- preparing a supporting surface 14 positioned downstream of the transport channel 12 relative to the feed direction A and at a height lower than that of the transport channel 12, and a pusher device 15 slidable on the supporting surface 12, parallel to the feed direction A, and

- positioning the pusher device 15 behind a rear wall 10a of the box 10 in a withdrawn position, whilst the box 10 falls from the transport channel 12 onto the supporting surface 14, and pushing the fallen box 10 towards the weighing unit 13.

It should be noted that the method comprises, after the weighing step:

- pushing the weighed box 10 away from the weighing unit 13 using the pusher device 15, along the feed direction A,

- returning the pusher device (15) to the withdrawn position.

The method also comprises, after the weighing step, a step of controlling the weight wherein if the weight of the box 10 measured by the weighing unit 13 does not fall within a window of predetermined acceptable values, the box 10 is expelled from the weighing unit 13 along an ejection direction transversal to the feed direction A, whilst if the weight of the box 10 measured by the weighing unit 13 falls within the window of predetermined acceptable values, the box 10 is pushed along the feed direction A.

It should be noted that the pusher device 15 is positioned in contact with the channel 12 when the pusher device15 is in the withdrawn position.

A method for making filter bags with infusion products comprises:

- feeding a web 2 of filter paper;

- dosing a product on the web 2 of filter paper at predetermined distances;

- closing the web 2 wrapping the doses of products;

- separating the filter bags from each other with the product inside them;

- stacking the filter bags forming groups of stacked filter bags;

- forming and moving empty boxes 10 towards a position for receiving groups of stacked filter bags;

- transporting the boxes 19 filled with the respective groups of filter bags along a transport channel 12 positioned along a feed direction A,

- weighing the boxes 10 filled with the respective groups of filter bags using a weighing unit 13 configured for checking the correct weight of each box 10 containing the respective group of filter bags according to the steps described above.

A weighing station and a packaging machine structured in this way thus achieve the preset aims thanks to the weighing station with reduced dimensions and extremely flexible for size changeover of the boxes.

The presence of a pusher device which is reduced in size, but extremely precise in the thrust movements of the boxes, reduces the components necessary for moving the boxes arriving in a pack from the transport channel.

This reduced size pusher device also allows an easier accessibility into the weighing station I zone (box feed channel and next supporting surface).

This feature greatly facilitates any removal or movement of the boxes present in the event of a machine shutdown.

The possibility of obtaining a synchronised positioning on the rear part of the box passing below the box during its falling reduces the necessary operating strokes of the boxes and therefore the sizing of the weighing station.

Claims

1. A station for weighing boxes (10) containing a respective group of filter bags with infusion products, said weighing station (1 1 ) comprising:

- a channel (12) for transporting the boxes (10) containing the respective groups of filter bags, along a feed direction (A); and

- a weighing unit (13) configured to weigh each box (10) containing the respective group of filter bags, characterised by further comprising:

- a supporting surface (14) positioned downstream of the transport channel (12) with respect to the feed direction (A) and at a height lower than that of the transport channel (12), and

- a pusher device (15) slidably movable on the supporting surface (12), parallel to the feed direction (A), and configured to be moved between a withdrawn position in which it is positioned behind a rear wall (10a) of the box (10) which falls from the transport channel (12) onto the supporting surface (14), and a forward position in which it pushes the fallen box (10) toward the weighing unit (13).

2. The station according to claim 1 , wherein said weighing unit (13) is positioned flush with the supporting surface (14), that is, coplanar with the supporting surface (14).

3. The station according to claim 1 or 2, wherein the pusher device (15) comprises a rod (16) positioned perpendicularly to the feed direction (A).

4. The station according to any of the preceding claims, also comprising driving means (17) for moving the pusher device (15), configured to move the pusher device (15) in synchrony with the boxes (10) moving along the transport channel (12), to allow the pusher device (15) to slide under the box (10) as it falls onto the supporting surface (14).

5. The station according to any of the preceding claims, comprising ejection means (18) configured to eject the box (10) from the weighing unit (13) along an ejection direction transversely to the feed direction (A), when the weight of box (10) measured by the weighing unit (13) falls outside a window of accepted preset values.

6. The station according to any of the preceding claims, wherein the pusher device (15) has a height that does not exceed the height of the transport channel (12) from the supporting surface (14).

7. The station according to any of the preceding claims, comprising a gripping and pushing head (19) for gripping and pushing the boxes (10) filled with the groups of filter bags; said gripping and pushing head (19) being configured to push said box (10) along the transport channel (12) to make a line of accumulated boxes (10) to advance along the feed direction (A).

8. A packaging machine for making filter bags with infusion products, said machine comprising:

- a feeding station (1 ) configured to feed a strip (2) of filter paper;

- a dosing station (3) configured to dose a product on the strip (2) of filter paper forming doses of product at predetermined distances;

- a closing station (4) configured to close the strip (2) wrapping the doses of product;

- a cutting station (5) configured to separate filter bags with respective doses of product inside them;

- a carousel (6) equipped with radially protruding grippers (7) positioned downstream of the cutting station (5) and configured to receive the separated filter bags;

- a stacking station (8) configured to stack the filter bags released by the carousel (6) form groups of filter bags; and

- a forming station (9) configured to form and move empty boxes (10) towards a position for receiving the groups of filter bags; characterized by further comprising a weighing station (11 ) according to any of the preceding claims.

9. A method for weighing boxes (10) containing a respective group of filter bags with infusion products, said method comprising the steps of:

- conveying said boxes (10) containing the respective groups of filter bags through a transport channel (12) along a feed direction (A);

- weighing each boxes (10) containing the respective groups of filter bags using a weighing unit (13); wherein the weighing step comprises the following sub steps:

- providing a supporting surface (14) positioned downstream of the transport channel (12) with respect to the feed direction (A) and at a height lower than that of the transport channel (12), and a pusher device (15) slidably movable on the supporting surface (12), parallel to the feed direction (A), and

- positioning the pusher device (15) behind a rear wall (10a) of the box (10) at a withdrawn position, while the box falls from the transport channel (12) onto the supporting surface (14), and pushing the fallen box (10) toward the weighing unit (13).

10. The method according to claim 9, comprising, after the weighing step:

- pushing the weighed box (10) away from the weighing unit (13) by means of the pusher device (15), along the feed direction (A),

- returning the pusher device (15) to said withdrawn position.

11. The method according to claim 9 or 10, further comprising, after the weighing step: a weight checking step wherein if the weight of box (10) measured by the weighing unit (13) falls outside a window of acceptable preset values, the box (10) is ejected from the weighing unit (13) along an ejection direction transversely to the feed direction (A), while if the weight of box (10) measured by the weighing unit (13) falls within the window of acceptable preset values, the box (10) is pushed along the feed direction (A).

12. The method according to any of the claims 9 - 11 , wherein the pusher device (15) is positioned in contact with the channel (12) when the pusher (15) is in said withdrawn position.