EP2730401A2

EP2730401A2 - Horizontal flexible container forming and filling machine and method for controlling a cutting device of said machine

Info

Publication number: EP2730401A2
Application number: EP13380035.9A
Authority: EP
Inventors: Enric Marti Roche; Francisco Mora Flores; Menna Fité Sala
Original assignee: Mespack SL
Current assignee: Mespack SL
Priority date: 2012-11-09
Filing date: 2013-09-05
Publication date: 2014-05-14
Also published as: EP2730401A3; ES2460467B1; ES2460467A2; ES2460467R1

Abstract

The machine comprises a conveyor device moving a continuous band of preformed containers (BP) step by step in a forward movement direction (D), a cutting device (2) with cutting blades (3a, 3b) operated for cutting the continuous band of preformed containers (BP) transversely in sites related with transverse welding lines (ST) of the continuous band of preformed containers (BP), and an automatic cutting correction device comprising detection means (4) arranged for detecting a plurality of successive detectable elements (21) in the continuous band of preformed containers (BP), and an actuator (5) operatively connected for moving and positioning the cutting device (2) along guide means parallel to the forward movement direction (D) in response to a positioning signal generated from a detection signal emitted by said detection means (4).

Description

Field of the Art

The present invention generally relates to a horizontal flexible container forming and filling machine and more particularly to a horizontal flexible container forming and filling machine which is provided with a cutting device for cutting a continuous band of preformed containers and an automatic cutting correction device correcting the position of the cutting device according to slight variations in the site of the continuous band of preformed containers where the cut must be made.
The present invention also relates to a control method for controlling the mentioned automatic cutting correction device associated with the cutting device.

Background of the Invention

Patent ES 2369459 A1 discloses a horizontal flexible container forming and filling machine comprising a band supply unit supplying a band of heat-sealable sheet material from a reel, a container forming unit forming individual flexible containers from said band of sheet material, and a filling unit filling the individual flexible containers with one or more products, sealing and delivering them to an outfeed conveyor. The container forming unit includes a folding station, where the band of sheet material is longitudinally folded into "V" or "W" shape, welding stations where a plurality of lower and transverse welding lines are performed defining a continuous band of preformed containers having a plurality of preformed containers, and a cutting station where the continuous band of preformed containers is transversely cut to form the individual flexible containers.
The mentioned cutting station includes one or more pairs of cutting blades between which the continuous band of preformed containers passes, and cutting operation means cyclically moving said cutting blades for cutting the continuous band of preformed containers transversely in sites related with said transverse welding lines and thus forming individual flexible containers. The position of the cutting blades in the cutting station is selected according to the position of welding elements in the welding station to make the mentioned sites where the transverse cuts are made coincide with said sites related with the transverse welding lines.
Typically, the transverse welding lines are grouped by pairs of welding lines separated by a small space, and the cuts are made in this small space, such that the front welding line of each pair forms the rear edge of an individual flexible container and the rear welding line forms the front edge of the next individual flexible container. Alternatively, the transverse welding lines can include relatively wide individual welding lines, and the cuts are made in the middle of these relatively wide welding lines with an equivalent result.
Due to a certain elasticity which the sheet material forming the continuous band of preformed containers generally has, and to other factors, such as the effect caused by the weldings in the sheet material, the position of the sites related with the transverse welding lines where the cuts must be made can experience small variations along the continuous band of preformed containers.
One drawback of the machines of the type described in the mentioned patent ES 2369459 A1 is that the position of the cutting blades in the cutting station can be adjusted when the work starts but not when the machine is operating, which results in the fact that the cuts are sometimes not made in the envisaged sites and that the obtained individual flexible containers are unsuitable. The negative result worsens over time due to error accumulation in the positions of the sites where the cuts must be made.

Summary of the Invention

The objective of the present invention is to solve the foregoing and other drawbacks by providing a horizontal flexible container forming and filling machine which is provided with an automatic cutting correction device, as well as a control method for controlling the cutting device by means of said automatic cutting correction device.
According to a first aspect, the present invention provides a horizontal flexible container forming and filling machine comprising a conveyor device moving a continuous band of preformed containers step by step in a forward movement direction, and a cutting device having one or more pairs of cutting blades arranged such that the continuous band of preformed containers passes between the two cutting blades of each pair. The continuous band of preformed containers has formed therein a plurality of transverse welding lines defining a plurality of preformed containers, and the cutting device includes cutting operation means moving said cutting blades for cutting the continuous band of preformed containers transversely in sites related with said transverse welding lines, and thus forming individual flexible containers.
The cutting device is associated with an automatic cutting correction device comprising detection means located upstream of the cutting device and arranged for detecting a plurality of successive detectable elements in the continuous band of preformed containers, and an actuator moving and positioning the cutting device along guide means parallel to the forward movement direction in response to a positioning signal generated from a detection signal emitted by said detection means.
The mentioned detectable elements can consist of contours, cuts, notches, etc., formed in a longitudinal edge of the continuous band of preformed containers, or of indications printed on the continuous band of preformed containers, but in any case the detectable elements are positioned consecutively in relation to the transverse welding lines and there is at least one detectable element associated with each preformed container of the continuous band of preformed containers.
In one embodiment, the detection means include an artificial viewing device fixed to a bedplate of the machine and arranged for capturing consecutive images of consecutive portions of the continuous band of preformed containers, where each of said consecutive portions includes at least one of said detectable elements. Optionally, the detection means further include a lighting device, such as a flash for example, associated with said artificial viewing device.
According to a possible embodiment, the cutting device comprises a base support fixed to the bedplate of the machine, and a moveable support, in which said one or more pairs of cutting blades and said cutting operation means are installed, movably connected to said base support by the guide means. In this case, the mentioned actuator has a fixed body fixed to the base support and a moveable element connected to the moveable support, or vice versa. The fixed body of the actuator preferably comprises an electric servomotor, the operation thereof can be controlled with precision by electronic control means, and the moveable element of the actuator comprises an extendable rod operated by the servomotor through a mechanical transmission.
In a particular embodiment, the guide means comprise a runner fixed to said moveable support and one or more runner guiding elements fixed to the base support and movably coupled to said runner. For example, the runner can have inclined side surfaces converging from top to bottom, and correspondingly said one or more runner guiding elements can comprise rolling elements assembled on the base support and arranged for rolling over said inclined side surfaces of the runner, such that the moveable support fixed to the runner is supported on said rolling elements and has freedom of movement in said direction parallel to the forward movement direction.
One or more pairs of band guiding elements arranged in fixed positions such that the continuous band of preformed containers passes between the two band guiding elements of each pair are installed on the moveable support of the cutting device. Each pair of band guiding elements is arranged in a position adjacent to and upstream of one of the one or more pairs of cutting blades and acts by holding the continuous band of preformed containers when it is cut by the corresponding pair of cutting blades.
According to a second aspect, the present invention provides a method for controlling a cutting device of a horizontal flexible container forming and filling machine such as that described according to the first aspect of the present invention. The method comprises the steps of detecting a plurality of successive detectable elements in the continuous band of preformed containers by using detection means located upstream of the cutting device, and moving and positioning the cutting device along guide means parallel to said forward movement direction by means of an actuator in response to a positioning signal generated from a detection signal emitted by said detection means.
The method comprises using an artificial viewing device as a component of said detection means, in which case said step of detecting comprises capturing consecutive images of consecutive portions of the continuous band of preformed containers by means of said artificial viewing device, where each of said consecutive images includes at least one of said detectable elements, and emitting said detection signal which is representative of the consecutive images.
Next, the method comprises using electronic control means to compare the consecutive images taken by the artificial viewing device with a predefined image pattern stored in a memory, and generating said positioning signal when a deviation is detected between one of the consecutive images taken by the artificial viewing device and said image pattern.
As indicated above, the conveyor device of the machine moves the continuous band of preformed containers by means of a step by step movement combining forward movements with brief periods of stop time during which the cutting device makes the cut. According to this feature, the method also comprises controlling the operation of the artificial viewing device in coordination with the operation of the conveyor device by using the electronic control means, such that the consecutive images are taken by the artificial viewing device during the time periods in which the continuous band of preformed containers is stopped between consecutive forward movements.

Brief Description of the Drawings

The foregoing and other features and advantages will be better understood from the detailed description of an embodiment with reference to the attached drawings, in which:

Fig. 1 is a perspective view of a horizontal flexible container forming and filling machine according to an embodiment of the present invention;
Fig. 2 is a perspective view of a cutting station of the machine of Fig. 1, including a cutting device associated with an automatic cutting correction device, shown in relation to a continuous band of preformed containers to be cut;
Fig. 3 is a side view of the continuous band of preformed containers of Fig. 2;
Fig. 4 is a plan view of the cutting device of Fig. 2;
Fig. 5 is a cross-section view taken along plane V-V of Fig. 4; and
Fig. 6 is a cross-section view taken along plane VI-VI of Fig. 4.

Detailed Description of an Embodiment

Referring first to Fig. 1, there is shown a horizontal flexible container forming and filling machine according to an embodiment of the present invention, which essentially comprises a band supply unit 100 supplying a band of heat-sealable sheet material B from a reel 101, a container forming unit 200 forming individual flexible containers E from said band of sheet material B, and a filling unit 300 filling the individual flexible containers E with one or more products, sealing and delivering them to an outfeed conveyor 330.
The container forming unit 200 includes a folding station 210 where the band of sheet material B is longitudinally folded into "V" or "W" shape, welding stations 211, 212 where a plurality of lower welding lines SI and transverse welding lines ST are performed defining a continuous band of preformed containers BP (also see Fig. 3), which comprises a plurality of preformed containers EP defined by said transverse welding lines ST, and a cutting station 220 where the continuous band of preformed containers BP is transversely cut to form the individual flexible containers E. A conveyor device (not shown) moves the continuous band of preformed containers BP step by step in a forward movement direction D along the container forming unit 200.
Fig. 3 shows an example of continuous band of preformed containers BP which comprises the mentioned transverse welding lines ST grouped into groups of two, where the two transverse welding lines ST of each group are separated by a small space G along which the transverse cut must be made to form the individual flexible containers E, such that the front welding line ST of each group of two forms the rear edge of the individual flexible container E which has just been separated and the rear welding line ST of each group of two will form the front edge of the next individual flexible container E.
The upper edge of the continuous band of preformed containers BP is welding free, such that the preformed containers EP have an upper opening through which they will be filled with one or more products by means of metering devices 310 in the filling unit 300, and this upper opening will then be sealed by means of an upper welding line (not shown) in an additional welding station 320 of the filling unit 300.
Notches M are formed next to said upper edge of the continuous band of preformed containers BP shown in Fig. 3, each of said notches defining a vertical edge MV aligned with the space existing between each group of two transverse welding lines ST and an inclined edge MI in which a nozzle and cap assembly T previously installed in a corresponding station (not shown) of the container forming unit 200 is arranged. Each transverse cut must coincide with the mentioned vertical edge MV of the corresponding notch M to prevent malformations in the front and rear edges of the individual flexible containers E, so the positioning of the cuts is critical.
The vertices formed by the convergence of the vertical edges MV of the mentioned notches M with the upper edge of the continuous band of preformed containers BP are used as detectable elements 21 in the cutting control method of the horizontal flexible container forming and filling machine of the present invention, as will be explained below. Nevertheless, a person skilled in the art will understand that the continuous band of preformed containers BP can have numerous configurations which are different from that the shown in Fig. 3, and that other features of the continuous band of preformed containers BP, such as printed indications or marks, for example, can alternatively be used as detectable elements which can be detected by the device and method of the present invention.
Fig. 2 shows in greater detail the mentioned cutting station 220 which comprises a cutting device 2 associated with an automatic cutting correction device. The cutting device 2 comprises two pairs of cutting blades 3a, 3b between which the continuous band of preformed containers BP passes and cutting operation means (not shown) closing and opening these two pairs of cutting blades 3a, 3b for brief periods of time in which the continuous band of preformed containers BP is stopped between consecutive forward movements during its step by step movement for cutting the continuous band of preformed containers BP transversely in sites between the two transverse welding lines ST of each group of two and thus forming the individual flexible containers E.
The cutting device 2 comprises a base support 9 fixed to a bedplate of the machine (not shown), and a moveable support 10 in which the two pairs of cutting blades 3a, 3b which can rotate about a common axis 22, and the mentioned cutting operation means are installed. Two pairs of band guiding elements 12a, 12b between which the continuous band of preformed containers BP passes are also installed on the moveable support 10. Each of these pairs of band guiding elements 12a, 12b is in a position adjacent to and upstream of one of the two pairs of cutting blades 3a, 3b. Therefore, the continuous band of preformed containers BP is held by the pairs of band guiding elements 12a, 12b when the pairs of cutting blades 3a, 3b are operated for cutting the band.
This moveable support 10 is movably connected to the base support 9 by guide means parallel to said forward movement direction D. An actuator 5 is operatively connected for moving and positioning the cutting device 2 along said guide means in response to a positioning signal generated by electronic control means from a detection signal emitted by detection means 4 located upstream of the cutting device 2, which will be described below.
The mentioned actuator 5 has a fixed body 5a fixed to the base support 9 and a moveable element 5b connected to the moveable support 10, although alternatively the assembly could be the other way round, i.e., the fixed body 5a fixed to the moveable support 10 and the moveable element 5b connected to the base support 9. In the illustrated example, the fixed body 5a includes an electric servomotor and the moveable element 5b includes an extendable rod connected to the electric servomotor by a mechanical transmission including an angle transmission 5c.
As shown in Figs. 5 and 6, the guide means comprise a runner 6 fixed to the moveable support 10 and one or more runner guiding elements fixed to the base support 9 and movably coupled to the runner 6. For example, the runner 6 has inclined side surfaces 6a converging from top to bottom, and the mentioned one or more runner guiding elements comprise rolling elements 13 assembled in the base support 9 and arranged for supporting the runner 6 and for rolling over said inclined side surfaces 6a of the runner 6.
Therefore, the moveable support 10 is supported in the base support 9 and has the possibility of moving along the runner 6 in the direction parallel to the forward movement direction D. The moveable element 5b of the actuator 5 is connected to the runner 6 of the moveable support 10 by a connecting element 14.
As shown in Fig. 6, a pair of camshafts 11a, 11b parallel to the forward movement direction D are assembled in the base support 9, which are rotated in a swinging manner by actuating means (not shown). These camshafts 11a, 11b are connected for moving, in a swinging manner, respective cam rods 19a, 19b coupled to corresponding forks 20a, 20b attached to the cutting blades 3a, 3b of each pair, respectively. The mentioned forks 20a, 20b can slide longitudinally along the cam rods 19a, 19b without being decoupled from same when the moveable support 10 is moved along the runner 6.
The mentioned automatic cutting correction device (Fig. 1) comprises the aforementioned detection means 4 which, in the illustrated example, include an artificial viewing device 7 located upstream of the cutting device 2 and arranged for capturing consecutive images of consecutive portions of the continuous band of preformed containers BP, where each of said consecutive portions includes one of the detectable elements 21, i.e., one of the notches M. Therefore, each of the consecutive images captured by the artificial viewing device 7 includes one of said detectable elements 21, i.e., one of the notches M.
The detection means 4 emit a detection signal which is representative of the captured consecutive images. The mentioned electronic control means include a memory in which a predefined image pattern is stored. According to the method of the present invention, the electronic control means compare the consecutive images taken by the artificial viewing device 7 with said predefined image pattern and generate a positioning signal mentioned above when a deviation is detected between one of the consecutive images taken by the artificial viewing device 7 and the stored image pattern.
The actuator 5 then moves and positions the cutting device according to this positioning signal to make the transverse cuts made by the pairs of cutting blades 3a, 3b coincide with precision with the vertical edges of the notches M of the continuous band of preformed containers BP.
The operation of the artificial viewing device 7 is preferably controlled by the electronic control means according to the operation of the conveyor device, such that the consecutive images are taken during the time periods in which the continuous band of preformed containers BP is stopped between consecutive forward movements during its step by step movement. Optionally, the detection means 4 further include a lighting device 8, a flash light for example, associated with said artificial viewing device 7.
In the embodiment illustrated in Fig. 1, the artificial viewing device 7 and the lighting device 8 of the detection means 4 are fixed to the bedplate of the machine by adjustment means which allow adjusting the position of the detection means with respect to the bedplate and accordingly with respect to the continuous band of preformed containers BP.
Therefore, the artificial viewing device 7 and the lighting device 8 are assembled in a detection support 15 connected to a first intermediate support 16 having a horizontal groove parallel to the forward movement direction. The detection support 15 can be fixed in a desired longitudinal position of said horizontal groove by means of a fixing element (not shown) inserted through same, and the first intermediate support 16 is fixed to a second intermediate support 17 having holes in which guide rods 18 fixed to the bedplate of the machine are inserted. The second intermediate support 17 can be fixed at a selected height of the guide rods 18 by a fixing element (not shown).
The features of the horizontal flexible container forming and filling machine of the present invention allow applying a control method for controlling the cutting device 2 comprising the steps of a) detecting a plurality of successive detectable elements 21 in the continuous band of preformed containers BP by using detection means 4 located upstream of the cutting device 2, and b) moving and positioning the cutting device 2 along guide means parallel to said forward movement direction D by means of an actuator 5 in response to a positioning signal generated from a detection signal emitted by said detection means 4.
A person skilled in the art will be able to introduce modifications and variations with respect to the embodiment shown and described without departing from the scope of the present invention as defined in the attached claims.

Claims

A horizontal flexible container forming and filling machine, comprising a conveyor device moving a continuous band of preformed containers (BP) step by step in a forward movement direction (D), said continuous band of preformed containers (BP) including a plurality of transverse welding lines (ST) defining a plurality of preformed containers (EP), and a cutting device (2) having one or more pairs of cutting blades (3a, 3b) between which the continuous band of preformed containers (BP) passes and cutting operation means moving said cutting blades (3a, 3b) for cutting the continuous band of preformed containers (BP) transversely in sites related with said transverse welding lines (ST) and thus forming individual flexible containers (E), characterized in that said cutting device (2) is associated with an automatic cutting correction device comprising detection means (4) located upstream of the cutting device (2) and arranged for detecting a plurality of successive detectable elements (21) in the continuous band of preformed containers (BP), and an actuator (5) operatively connected for moving and positioning the cutting device (2) along guide means parallel to said forward movement direction (D) in response to a detection signal emitted by said detection means (4).
The machine according to claim 1, characterized in that said detection means (4) include an artificial viewing device (7) arranged for capturing consecutive images of consecutive portions of the continuous band of preformed containers (BP), each of said consecutive portions including at least one of said detectable elements (21).
The machine according to claim 2, characterized in that said detection means (4) further include a lighting device (8) associated with said artificial viewing device (7).
The machine according to claim 3, characterized in that the cutting device (2) comprises a base support (9) fixed to a bedplate of the machine, and a moveable support (10) in which said one or more pairs of cutting blades (3a, 3b) and said cutting operation means are installed, said moveable support (10) being movably connected to said base support (9) by said guide means.
The machine according to claim 4, characterized in that said actuator (5) has a fixed body (5a) fixed to the base support (9) and a moveable element (5b) connected to the moveable support (10), or vice versa.
The machine according to claim 5, characterized in that said fixed body (5a) of the actuator (5) comprises an electric servomotor and said moveable element (5b) of the actuator (5) comprises an extendable rod.
The machine according to claim 4, characterized in that said guide means comprise a runner (6) fixed to said moveable support (10) and one or more runner guiding elements fixed to said base support (9) and movably coupled to said runner (6).
The machine according to claim 7, characterized in that the runner (6) has inclined side surfaces (6a) converging from top to bottom, and said one or more runner guiding elements comprise rolling elements (13) assembled in the base support (9) and arranged for rolling over said inclined side surfaces (6a) of the runner (6).
The machine according to claim 4, characterized in that one or more pairs of band guiding elements (12a, 12b) between which the continuous band of preformed containers (BP) passes are installed on the moveable support (10), each in a position adjacent to and upstream of one of the one or more pairs of cutting blades (3a, 3b).
The machine according to claim 4, characterized in that the cutting operation means comprise a pair of camshafts (11a, 11b) assembled in the base support (9) parallel to the forward movement direction (D), which are rotated in a swinging manner by actuating means, respective cam rods (19a, 19b) connected to said camshafts (11a, 11b), and corresponding forks (20a, 20b) integral with the cutting blades (3a, 3b) of each pair, respectively, coupled to said cam rods (19a, 19b) in a longitudinally sliding manner.
A control method for controlling a cutting device (2) of a horizontal flexible container forming and filling machine, where said machine comprises a conveyor device moving a continuous band of preformed containers (BP) step by step in a forward movement direction (D), said continuous band of preformed containers (BP) including a plurality of transverse welding lines (ST) defining a plurality of preformed containers (EP), said cutting device (2) having one or more pairs of cutting blades (3a, 3b) between which the continuous band of preformed containers (BP) passes and cutting operation means moving said cutting blades (3a, 3b) for cutting the continuous band of preformed containers (BP) transversely in sites related with said transverse welding lines (ST) and thus forming individual flexible containers (E), and where the method comprises the steps of:
a) detecting a plurality of successive detectable elements (21) in the continuous band of preformed containers (BP) by using detection means (4) located upstream of the cutting device (2); and

b) moving and positioning the cutting device (2) along guide means parallel to said forward movement direction (D) by means of an actuator (5) in response to a positioning signal generated from a detection signal emitted by said detection means (4).
The control method according to claim 11, characterized in that it comprises using an artificial viewing device (7) as a component of said detection means (4), and in that said step of detecting comprises capturing consecutive images of consecutive portions of the continuous band of preformed containers (BP) by means of said artificial viewing device (7), where each of said consecutive images includes at least one of said detectable elements (21), and emitting said detection signal which is representative of the consecutive images.
The control method according to claim 12, characterized in that it comprises controlling the operation of said artificial viewing device (7) according to the operation of said conveyor device by using electronic control means such that said consecutive images are taken during time periods in which the continuous band of preformed containers (BP) is stopped between consecutive forward movements during its step by step movement.
The control method according to claim 12, characterized in that it comprises using electronic control means to compare the consecutive images taken by the artificial viewing device (7) with a predefined image pattern stored in a memory, and generating said positioning signal when a deviation is detected between one of the consecutive images taken by the artificial viewing device (7) and said image pattern.