Sealing and cutting device for forming filter-bags with infusion products

Abstract

A sealing and cutting device for forming bags containing products includes; a sonotrode for sealing a portion of a continuous tubular strip, feeding along a feed direction; a counterhead positioned facing the sonotrode; a movement system for moving the sonotrode and/or anvil between a first non-operating position, wherein the sonotrode and the anvil are apart, and a second operating position wherein the sonotrode and the anvil are in contact to simultaneously seal a head and bottom of respective bags. A cutting element includes a circular blade connected to a supporting and movement element which imparts a translational movement to the blade with a circular shape along a direction perpendicular to the feed direction of the strip. The anvil includes a slit from which the blade protrudes, for cutting the strip, by contact with the sonotrode in the second operating position, to separate a bag formed from the remaining strip.

Claims

1. A device for sealing and cutting a continuous tubular strip to form bags containing a product, the device comprising: a sonotrode configured to seal a portion of the continuous tubular strip advancing along a feed direction; an anvil positioned opposite the sonotrode; a movement system operatively coupled to at least one of the sonotrode or to the anvil, the movement system being configured to move the sonotrode and the anvil between a non-operating position, in which the sonotrode and the anvil are spaced apart, and an operating position in which the sonotrode and the anvil are in contact with one another to seal the tubular strip such that a head and a bottom of adjacent bags are simultaneously sealed; a cutting element including a circular blade operatively coupled to a support and movement unit, the support and movement unit being configured to translate the blade along a direction perpendicular to the feed direction of the tubular strip, the anvil including a slit through which the blade protrudes, wherein the blade is configured to cut the tubular strip by contacting the sonotrode while the sonotrode and the anvil are in the operating position, thereby separating a sealed bag from a remainder of the tubular strip.

2. The device according to claim 1, wherein the cutting element comprises a wheel having a circular blade profile, the wheel being articulated, and freely rotatable with respect to the support and movement unit, the support and movement unit being positioned within the anvil.

3. The device according to claim 2, wherein the support and movement unit comprises a support body coupled to an actuator configured to move the support body in both directions along a longitudinal extension of the anvil; and wherein the support body is slidably coupled to a linear guide positioned within the anvil to enable a rectilinear translation of the wheel in both directions.

4. The device according to claim 2, wherein the support body includes a rocker pivotally mounted to the support body, the rocker having a first arm and a second arm, the wheel being mounted on the first arm, and an adjusting screw being threaded into the second arm in contact with the support body, such that a position of the wheel protruding from the slit in the anvil is adjustable.

5. The device according to claim 1, wherein the cutting element comprises a wheel having a circular blade profile, the wheel being rigidly connected to the support and movement unit, the support and movement unit being positioned within the anvil.

6. The device according to claim 1, wherein the cutting element comprises a wheel having a circular blade profile, the wheel being articulated with respect to the support and movement unit positioned within the anvil; and wherein the wheel is operatively connected to an independent movement unit configured to impart forced rotation of the wheel, at least during translational movement of the blade.

7. The device according to claim 1, further comprising an elastic element interposed between the support and movement unit and the blade to maintain contact between the blade and the sonotrode when the device is in the operating position.

8. The device according to claim 1, wherein the sonotrode comprises a contact surface facing the anvil, the contact surface having a flat and continuous profile configured to permit the circular blade to slide therein, thereby facilitating cutting of the tubular strip by contact with the contact surface.

9. The device according to claim 1, wherein the slit in the anvil has a length at least equal to a length of the sonotrode in a sealing zone.

10. The device according to claim 1, wherein the anvil is formed as a single integral piece.

11. The device according to claim 1, wherein at least one of the sonotrode or the blade is made of a hardened material.

12. A method for sealing and cutting bags containing a product, the method comprising: providing a device for sealing and cutting a continuous tubular strip to form bags containing a product, the device comprising: a sonotrode configured to seal a portion of the continuous tubular strip advancing along a feed direction: an anvil positioned opposite the sonotrode; a movement system operatively coupled to at least one of the sonotrode or the anvil, the movement system being configured to move the sonotrode and the anvil between a non-operating position, in which the sonotrode and the anvil are spaced apart, and an operating position in which the sonotrode and the anvil are in contact with one another to seal the tubular strip such that a head and a bottom of adjacent bags are simultaneously sealed; a cutting element including a circular blade operatively coupled to a support and movement unit, the support and movement unit being configured to translate the blade along a direction perpendicular to the feed direction of the tubular strip, the anvil including a slit through which the blade protrudes, wherein the blade is configured to cut the tubular strip by contacting the sonotrode while the sonotrode and the anvil are in the operating position, thereby separating a sealed bag from a remainder of the tubular strip; feeding the continuous tubular strip along the feed direction; positioning the sonotrode and the anvil opposite one another, with the sonotrode configured to seal the portion of the tubular strip; moving the sonotrode and anvil towards each other along a direction transverse to the feed direction until the sonotrode and anvil contact the tubular strip; sealing the portion of the tubular strip by activating the sonotrode such that the head and the bottom of the adjacent bags are simultaneously sealed; cutting the sealed portion of the tubular strip using the cutting element including the circular blade, the cutting element translating the blade along the direction perpendicular to the feed direction, wherein the cutting is performed by the blade making contact with the sonotrode, thereby separating the sealed bag from the remainder of the tubular strip, and wherein the cutting step is performed simultaneously with the sealing step while the sonotrode is activated.

13. The method according to claim 12, wherein the continuous tubular strip is made of filter material and the product is an infusion product.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The technical features of the invention will become more apparent from the following detailed description of a preferred, non-limiting embodiment of it, illustrated by way of example in the accompanying drawings, in which:

(2) FIG. 1 is a schematic front view, with some parts cut away to better illustrate others, of a device for sealing and cutting for forming filter bags for infusion products according to this invention;

(3) FIG. 2 is a perspective view of a scaled-up detail of a sonotrode and an anvil forming part of the sealing and cutting device of FIG. 1;

(4) FIG. 3 is a front perspective view of the anvil of the cutting device;

(5) FIGS. 4 and 5 are perspective views, with some parts cut away to better illustrate others, of the sonotrode and anvil unit in a non-operating position and with a cutting element positioned on the anvil in two different operating positions;

(6) FIG. 6 is a perspective view of the movement unit of the cutting element of the previous drawings;

(7) FIG. 7 is a cross section of the movement unit of the cutting element of FIG. 6.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

(8) With reference to the accompanying drawings, and in particular to FIGS. 1 and 2, the device according to the invention, labelled 100 in its entirety, is used for sealing (by ultrasound) and cutting so as to form bags containing products of different types.

(9) In the case illustrated, purely by way of a non-limiting example, the formation of filter bags for infusion products is described.

(10) Therefore, again by way of example, the sealing and cutting device 100 may be used on machines (not illustrated) for forming filter bags configured to form both the three-dimensional filter bags such as the pyramid bags and the so-called traditional single-lobed or double-lobed bags with a rectangular shape.

(11) Each bag is obtained with a piece of material containing at least one dose of product. In the case of filter bags, each filter bag is obtained with a piece of filter material containing a dose of infusion product.

(12) Described below is the bag to be joined and cut from by device according to the invention, such as a filter bag obtained with filter material, but the solution according to the invention may be applied any other type of bag containing a product without limiting the scope of the solution.

(13) The sealing and cutting device 100 comprises a sealing head 1 or sonotrode configured for sealing a portion 2 of a continuous tubular strip 2s of filter material (illustrated with a dashed line in FIGS. 1 and 2), feeding along a feed direction D2 (in such a way as to define a closed head of a first filter bag already provided with a dose of product and the bottom of a second filter bag being formed upstream of the first relative to the feed direction D2).

(14) The direction of feed of the strip 2s may be along a vertical plane, a horizontal plane or an inclined plane depending on the type of forming machine on which the device 100 is applied.

(15) The sealing and cutting device 100 comprises a counterhead or anvil 3 positioned facing the sonotrode 1.

(16) The anvil 3 has a box-shaped structure with a length (or main longitudinal extension) at least equal to or greater than the length of the sonotrode 1.

(17) The sealing and cutting device 100 comprises a movement system 4 connected to the sonotrode 1 and/or to the anvil 3 and configured for moving the sonotrode 1 and the anvil 3 (in a synchronised fashion) between a first non-operating position, wherein the sonotrode 1 and the anvil 3 are spaced apart, and a second operating position wherein the sonotrode 1 and the anvil 3 are in front contact for sealing the portion 2 of the strip of filter material, in such a way as to form a simultaneous sealing of a top and bottom of respective bags to be formed.

(18) The sonotrode 1 and the anvil 3 are moved in a synchronised fashion along a direction D3 of movement transversal to the feed direction D2 of the continuous strip 2s of filter material.

(19) The movement system 4 (connected to the sonotrode 1) comprises a plurality of kinematic mechanisms (such as pairs of connecting rods and cranks and relative drive units) which are able to synchronise the movement towards and away from the sonotrode 1 and the anvil 3.

(20) The sealing and cutting device 100 comprises a cutting element 5 comprising a circular blade 6 connected to a supporting and movement element 8 which is able to impart a translational movement to the blade 6 with a circular shape along a direction D6 perpendicular to the feed direction D2 of the continuous tubular strip 2s.

(21) It should be noted that the cutting element 5 is positioned on the anvil 3 and configured to cut the strip 2s of filter material, with the sonotrode 1 and the anvil 3 in the second operating position, in such a way as to separate the first filter bag formed from the remaining continuous strip 2s of filter material.

(22) As illustrated also in FIGS. 3 to 7, the anvil 3 comprises a slit 7 from which the blade 6 protrudes, which is configured for cutting the tubular strip 2s, by contact with the sonotrode 1, whilst the sonotrode 1 and the anvil 3 are in the second operating position, in such a way as to separate a bag formed from the remaining continuous strip 2s.

(23) According to a first embodiment, the cutting element 5 comprises a wheel 6a with a circular blade profile 6 articulated, and freely rotatable, with the movement and support unit 8 positioned inside the anvil 3.

(24) According to a second embedment, the cutting element 5 comprises a wheel 6a with a circular blade profile 6 associated rigidly with the movement and support unit 8 positioned inside the anvil 3.

(25) According to a third embodiment, the cutting element 5 comprises a wheel 6a with a circular blade profile 6 articulated with the movement and support unit 8 positioned inside the anvil 3.

(26) In light of this, the wheel 6a is connected to an independent movement unit 9 configured to impart the forced rotation to the wheel 6a, at least during the translation movement of the blade 6 (irrespective of the contrast with the sonotrode 1).

(27) The independent unit 9 is illustrated with a block in FIG. 7 and may consist of a drive unit or a kinematic coupling with a pinion-rack unit which is able to rotate the wheel 6 when the movement and support means 8 are activated.

(28) Preferably, the movement and support unit 8 comprises a body 10 for supporting the wheel 6a connected to an actuator 11 configured for moving, in both directions, the supporting body 10 along the longitudinal extension of the anvil 3.

(29) In light of this, the supporting body 10 is slidably connected to a linear guide 12 positioned inside the anvil 3 in such a way as to allow a rectilinear stroke of translation in both directions of the wheel 6a.

(30) Preferably, the supporting body 10 comprises a rocker 13 articulated in its central part to the supporting body 10.

(31) The rocker 13 has a first arm 14 and a second arm 15.

(32) The wheel 6a is articulated on the first arm 14 (on the free end of the first arm 14). A grub screw 16 for adjusting and counter-balancing in contact with the supporting body 10 is screwably connected on the second arm 15 in such a way as to adjust the operating position of the wheel 6a protruding from the slit 7.

(33) In light of this, an elastic preloading element 17 (a spring) is interposed between the supporting element 8 (the supporting body 10) and the blade 6 (the first arm 14) and is able to keep the blade 6 in contact with the sonotrode 1 in the second operating position.

(34) As illustrated, the sonotrode 1 comprises a contact surface 18, facing the anvil 3 with a flat and continuous profile on which the blade 6 with a circular profile can slide in such a way as to determine a cut of the tubular strip 2s of filter material by making contact with the contact surface 18.

(35) Preferably, the anvil 3 has the slit 7 with a length S7 at least equal to the length S1 of the sonotrode 1 in the sealing zone (preferably, the slit 7 may have an extension greater than the extension of the sonotrode 1).

(36) Preferably, the anvil 3 is made as a single piece.

(37) Preferably, the sonotrode 1 and/or the blade 6 are made of hardened materials. The invention also provides a method for sealing and cutting bags (filter) containing infusion products.

(38) The method comprises the following steps: preparing a sealing head 1 or sonotrode configured for sealing a portion 2 of a continuous tubular strip 2s of filter material, feeding along a feed direction D2; preparing a counterhead or anvil 3 positioned facing the sonotrode 1; moving the sonotrode (1) and anvil (3) towards each other along a direction (D3) of movement transversal to the direction (D2) of feeding the continuous tubular strip (2s) of filter material, until contact with the tubular strip (2s) of filter material; joining the portion 2 of the tubular strip 2s of filter material, by activating the sonotrode 1, in such a way as to achieve a simultaneous sealing of a head and of a bottom of respective bags to be formed (as in the case illustrated, a closed head of a first filter bag already provided with a dose of product and the bottom of a second filter bag being formed positioned upstream of the first relative to the feed direction D2); cutting along the portion 2 of continuous tubular strip 2s of sealed filter material, using a cutting element 5, in such a way as to separate a filter bag formed from the remaining continuous tubular strip 2s of filter material; this cutting step comprises a translation of the cutting element 5 with the blade 6 in a circular shape along a direction D6 perpendicular to the feed direction D2 of the continuous tubular strip 2s.

(39) As illustrated, the cutting step is performed by the blade 6 by contact on the sonotrode 1.

(40) It should also be noted that the cutting step comprises a translation of the cutting element 5 with the blade 6 having a circular shape along a direction D6 perpendicular to the direction D3 of movement of the sonotrode 1 and the anvil 3.

(41) It should be noted that the translation of the cutting element 5 occurs along the entire longitudinal extension of the sonotrode 1 and the anvil 3 to allow a secure and complete separation of the filter bag formed relative to the remaining strip of filter material.

(42) Preferably, during the cutting step by the cutting element 5 with the blade 6 with a circular shape occurs during the sealing step of the activated sonotrode 1.

(43) The preset aims with numerous advantages are achieved thanks to a machine structured in this way.

(44) The presence of a circular blade (preferably rotating) makes it possible to increase the working life of the blade.

(45) The presence of a flat sonotrode which defines a surface for contact with the circular blade increases the safety and precision of cutting the stretch of strip of filter material.

(46) The presence of a circular blade which is movable along a linear trajectory along the extension of the sonotrode and anvil makes it possible to cut with the sonotrode switched on in such a way as to improve the times and allow a clean and precise cutting of the stretch of filter material without fraying the edges of the cut stretches.