Method for controlling a plurality of carts movable along a track - Patents.com

Abstract

A method for controlling a plurality of carts (8) movable independently of one another along an endless track (7) and configured to perform at least one task to perform at least one operation on each of the articles (3) is described, the method comprising the following steps: a) advancing the carts (8) along the track (7), the track (7) including at least one task section (13) and at least one temporary section (14); and b) advancing a section of the track (7) located upstream of the at least one task section (13). The method includes advancing each cart (8) along a task assignment section (16); c) advancing a plurality of articles (3) along a supply path (Q) and through an operation station (A) where an operation is performed; d) detecting the path of each article (3) at a detection station (D) of the supply path (Q) located upstream of the operation station (A); and e) controlling each cart (8) to perform at least one task if an article (3) is detected during the detecting step d) as the cart (8) moves along the task assignment section (16).

Description

[Technical field]

[0001] The present invention relates to a method for controlling a plurality of carts movable independently of one another along an endless track, in particular a closed loop track, and configured to perform at least one operation on each of the items, in particular a package-related operation, more particularly the application of a cap or closure on a package containing a pourable product. [Background technology]

[0002] As is generally known, many pourable food products, such as fruit juice, UHT (ultra-high temperature treated) milk, wine, tomato sauce, etc., are sold in packages made from sterilized packaging materials.

[0003] A typical example is the parallelepiped-shaped package for pourable food products known as Tetra Brik Aseptic®, which is made by folding and sealing laminated webs of packaging material. The packaging material has a multi-layer structure including a base layer, e.g. made from paper, covered on both sides with layers of heat-sealed plastic material, e.g. polyethylene. In the case of aseptic packages for long-term storage products such as UHT milk, the packaging material also includes a layer of oxygen barrier material, e.g. aluminum foil, superimposed on the layer of heat-sealed plastic material and then covered with another layer of heat-sealed plastic material that finally forms the inner surface of the package that contacts the food product.

[0004] Such packages are typically produced in a fully automated packaging assembly in which a continuous tube is formed from a web of packaging material fed to such a packaging assembly. The web of packaging material is sterilized in the packaging assembly by adding a chemical sterilant, e.g. hydrogen peroxide, which is removed from the surface of the packaging material once sterilization is complete, e.g. evaporated by heating. The web so sterilized is then maintained in a closed sterile environment and folded longitudinally and sealed to form a tube, which is fed along a vertical advance direction.

[0005] To complete the forming operation, the tube is top-filled with sterilized food product, sealed, and then cut along equally spaced transverse cross sections.

[0006] A pillow pack having a longitudinal sealant strip, a top lateral sealant strip and a bottom lateral sealant strip is thereby obtained.

[0007] Known package assemblies typically include a forming unit configured to form a pillow pack, where a tube is subsequently filled downwards with a sterilized or pasteurized food product, formed, sealed and then cut along the aforementioned cross section to obtain the pillow pack.

[0008] The pillow packs are then fed to a folding unit for forming a fully folded package.

[0009] Once formed, such packages may undergo further processing such as the attachment of an opening device to allow the product to be poured out, in some embodiments the opening device is typically fitted directly onto the package after it has been formed, sealed and folded at an attachment unit located on the production line downstream from the folding unit.

[0010] It is known to use a package assembly that includes a number of carts that are movable independently of one another along respective tracks to perform operations on pillow packs or packages.

[0011] The use of such tracks and independently movable carts is known, for example, to form, seal, or fold the pillow packs described above.

[0012] Linear motors are typically used to achieve independent movement of the carts.

[0013] Thus, each track typically includes an individual energizable solenoid, e.g., an electric coil, while each of the carts typically includes a permanent magnet, and the resulting linear motors are configured to be independently controlled in a known manner to propel the carts along their respective track or tracks.

[0014] It is also known to use carts that are movable independently of one another along endless tracks for mounting opening devices onto packages, as described in WO2014097275.

[0015] In particular, WO2014097275 describes a mounting unit for mounting an opening device onto each sealed package containing a pourable food product. The mounting unit includes an infinite closed-loop track and a number of carts that, in use, move independently of each other along the track using linear motors.

[0016] Each cart carries one gripping device configured to cyclically receive a respective opening device, transport the opening device along the track, and attach the opening device onto each package advancing along an advancement path disposed beneath the track.

[0017] After receipt and prior to installation, each opening device is also coated with glue using a glue application device such as a glue gun.

[0018] Attachment of the opening device occurs along a branch of the track that faces the advancement path. Summary of the Invention [Problem to be solved by the invention]

[0019] While reliable, effective and functionally effective, the above-described mounting unit still has room for further improvement, specifically, simplifying the control of the cart along the tracks and optimizing the dynamics of the cart moving along the tracks. [Means for solving the problem]

[0020] It is therefore an object of the present invention to provide a method for controlling a plurality of carts movable independently of one another along a track and configured to perform at least one operation on each of the items, designed to meet at least one of the above-mentioned needs in a simple and cost-effective manner.

[0021] This object is achieved by a method for controlling a plurality of carts, movable independently of one another along an endless track, according to claim 1.

[0022] Non-limiting embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0023] [Figure 1] 1 shows a unit for mounting and operating an opening device on a sealed package containing a pourable food product according to a method for controlling a plurality of carts according to the present invention. [Diagram 2] FIG. 2 is a schematic side view, with parts removed for clarity, of the unit of FIG. 1 during a given operating condition; [Diagram 3] FIG. 2 is a schematic side view of the unit of FIG. 1 with parts removed for clarity, during a further operating situation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] With reference to the accompanying drawings, the number 1 indicates as a whole a unit for mounting an opening device 2 onto a sealed package 3 containing an article, in particular a pourable product, preferably a pourable food product, such as UHT i.e. pasteurised milk, fruit juice, wine, water etc.

[0025] The package 3 is produced upstream of the unit 1 using a known packaging machine (not shown) starting from a sheet of packaging material which is first folded into a tube, then sealed longitudinally, then formed and sealed transversely and finally folded according to a process which is known per se and which is not shown or described in detail.

[0026] The packaging material has a multi-layer structure (not shown) and comprises a layer of a fibrous material, for example paper, covered on both sides with layers of a heat-sealable plastic material, for example polyethylene.

[0027] In the case of an aseptic package 3 for a long shelf life product such as UHT milk, the packaging material also includes a layer of gas and light barrier material, for example aluminium foil or ethylene vinyl alcohol (EVOH) film, which is superimposed on the layer of heat sealable plastic material and then covered with another layer of heat sealable plastic material, the latter forming the inner surface of the package 3 that ultimately contacts the pourable product.

[0028] Each opening device 2 is adapted to be attached onto a package 3 in a removable part thereof, ie in a part that is removable from the remainder of the package 3 in order to allow the pourable product to flow out.

[0029] The removable part may consist of a sealing sheet attached by gluing or heat sealing onto the package 3 to close its through hole, or alternatively the removable part may be defined by a so-called "pre-laminated" hole, i.e. a hole formed in a base layer of the packaging material and sealed closed by another layer of the packaging material (at least a layer of heat-sealable plastic material).

[0030] Each package 3 is, in the embodiment shown, a parallelepiped and has a top wall 4 on which the respective opening device 2 is mounted by the unit 1, and a bottom wall opposite the top wall 4.

[0031] Additionally, each package 3 has a pair of lateral walls 5 extending perpendicularly between the top wall 4 and the bottom wall.

[0032] In the embodiment shown, the top wall 4 lies in a horizontal plane.

[0033] Unit 1 is - conveying means 6 arranged, in the embodiment shown, to advance the packages 3 along a linear feed path Q; -Infinite closed loop trajectory 7, a number of carts 8 movably connected to the track 7 and movable, in particular slidable, along the track 7 independently of one another; - Substantially comprising a control unit 10 operably coupled to the track 7 and the cart 8.

[0034] The conveying means 6 includes a linear conveyor 6a which extends along the feed path Q and which cooperates with a bottom wall of the packages 3 to feed the packages 3 along the feed path Q in use.

[0035] In the embodiment shown, the linear conveyor 6a advances the packages 3 along the feed path Q at a random pitch.

[0036] The track 7 houses a stator armature (not shown) formed by a plurality of individually excitable solenoids (known per se), each housing a permanent magnet (known per se) such that, in use, the carts 8 are moved individually along the track 7 by individually controlling the solenoids using a control unit 10.

[0037] In other words, the track 7 and the cart 8 together define a linear motor.

[0038] Preferably, the orbit 7 has a substantially elliptical configuration.

[0039] In view of the above, the track 7 is infinite in a closed loop manner, so that each cart 8 is movable cyclically along the track 7 .

[0040] More specifically, the cart 8 is configured to continue to move forward along a track 7 driven by the interaction between a solenoid and a permanent magnet controlled by a control unit 10 according to a technique more fully described below.

[0041] The cart 8 is configured to perform at least one task, in particular a number of tasks, for carrying out an operation on each package 3 .

[0042] Thus, the track 7 passes through operation stations where operations are performed, and the linear conveyor 6a is arranged to advance the packages 3 through the operation stations.

[0043] Hence, both the track 7 and the linear conveyor 6a extend through (at) the handling station.

[0044] According to the preferred embodiment shown, each cart 8 is configured to perform three tasks, namely receiving and / or picking up one opening device 2 at a receiving station R arranged along the track 7, applying and / or determining a glue application on an opening device 2 previously received at the receiving station R, and attaching the previously received and glued opening device 2 onto the respective package 3 advanced by the conveying means 6.

[0045] For this purpose, Unit 1: an infeed assembly 11 configured to feed the opening devices 2 to the cart 8 at the receiving station R; a gluing assembly 12 arranged downstream of the feed assembly 11 relative to the forward direction of the carts 8 along the track 7 and configured to apply a layer of glue or any suitable adhesive substance onto the fastening portion (not shown) of each opening device 2 carried by each cart 8.

[0046] In particular, the gluing assembly 12 is disposed at a gluing station G downstream of a receiving station R.

[0047] Therefore, orbit 7 is - along with it, the cart 8 has a number of task compartments 13, each configured to perform a task, in a specific embodiment one of the aforementioned tasks, a number of temporary compartments 14 along which the cart 8 is adapted to advance inactively, i.e. without performing any of the aforementioned tasks.

[0048] The term "inactive" here is meant to indicate an operating condition in which the cart 8 continues to advance along the track 7 and perform all predetermined movements, but "in an inactive manner", e.g., does not receive an opening device or is not supplied with glue.

[0049] In practice, the task compartment 13 is located and specifically defined at the location where the infeed assembly 11 and the glue application assembly 12 are located.

[0050] Furthermore, the third task compartment 13 is placed and specifically defined in a position for attaching the already received and glued opening device 2 onto the package 3 when the cart 8 is in use, i.e. downstream of the gluing assembly 12.

[0051] In view of the above, the above operations performed by each cart 8 on each package 3 are defined by mounting one opening device 2 on each package 3, and the above tasks (receiving the opening device 2, applying glue to the opening device 2, and attaching the opening device 2 to the package) are part of such operations.

[0052] In other words, each operation is completed (executed) as soon as all tasks are performed.

[0053] The above-mentioned operating station is therefore defined by an attachment station A, in which each cart 8 attaches (by carrying out the attaching task and having already carried out the receiving and gluing tasks) one opening device 2 onto each package 3 advanced by the linear conveyor 6a at the attachment station A itself.

[0054] Advantageously, each cart 8 is equipped with a gripping device (not shown) configured to receive one opening device 2 at a time at the receiving station R.

[0055] The gripping device then mounts, in particular affixes, a respective opening device 2 onto a respective package 3 at mounting station A, which is located downstream of glueing station G.

[0056] Opportunistically, this task is carried out in the embodiment shown in the lower branch of the track 7, at the branch of the track 7 facing the linear conveyor 6a.

[0057] Preferably, the infeed assembly 11 and the gluing assembly 12 are arranged in an upper branch of the track 7, the upper branch and the lower branch being connected to each other by two opposing curved branches.

[0058] The gluing assembly 12 is supported by fixed structure, not shown, of the unit 1 and reciprocates parallel to the upper branch to follow the carts 8 moving along their respective task sections 13 .

[0059] In an alternative not shown, the gluing assembly 12 can be stationary.

[0060] In particular, the gluing assembly 12 is known per se and comprises a number of gluing means, preferably guns, for applying glue onto each opening device 2 carried by a cart 8 moving along each task section 13 according to a given pattern (i.e. a predefined movement scheme, i.e. speed and acceleration scheme) determined by the control unit 10.

[0061] For example, a group of carts 8 can be grouped by the control unit 10 so as to define a batch of opening devices 2 which are glued in unison by the gun.

[0062] That is, if the gluing assembly 12 includes five guns (obviously the number of guns can be different and the above particular number is merely a preferred example), the control unit 10 determines a grouping of five carts 8 carrying respective opening devices 2 which are grouped together within respective task compartments 13 during use.

[0063] The verb "group" here refers to a conceptual grouping of carts 8, not necessarily physical, but may refer, for example, to the physical separation of a group of carts 8 from other carts 8.

[0064] The unit 1 further comprises a sensor 15 for detecting the path of each package 3 at a detection station D of the feed path Q, placed upstream of the attachment station A, relative to the direction of advance of the packages 3 along the feed path Q.

[0065] In practice, the sensor 15 is arranged to generate a signal correlated to the path of each package 3 at the detection station D and to transmit such a signal to the control unit 10 .

[0066] The track 7 further comprises a temporary section 14 , in particular a task assignment section 16 , located at a position upstream of the receiving station R, i.e. upstream of the task section 13 associated with the infeed assembly 11 .

[0067] In practice, the task assignment section 16 is spaced apart from the other task sections 13 along the track 7 , specifically from the task section 13 associated with the feed assembly 11 .

[0068] As shown diagrammatically in FIG. 2 , the control unit 10 is configured to control the cart 8 to perform at least one of the above tasks when a package 3 is detected by the sensor 15 at the detection station D as the cart 8 moves along the task assignment section 16.

[0069] More specifically, the control unit 10 is configured to control the cart 8 to perform all of the aforementioned tasks when a package 3 is detected by the sensor 15 and at the same time the cart 8 is moving along the task assignment section 16 .

[0070] Furthermore, if no package 3 is detected by the sensor 15 while a cart 8 is moving along the task assignment section 16, such cart 8 will not be assigned any task, i.e. the control unit 10 will prevent the assignment of any task to such cart 8 (Figure 3).

[0071] The above sentence "No task is assigned to such a cart 8" is meant here to mean that the cart 8 continues to move forward along the trajectory 7, but does not perform any of the above mentioned tasks.

[0072] Advantageously, however, such carts 8 continue to move according to a predefined motion scheme, i.e., velocity and acceleration scheme, imposed by the control unit 10. For example, in one embodiment, carts 8 that are not assigned any task will undergo slight acceleration and / or deceleration along the trajectory 7 that they would undergo if assigned a task.

[0073] In practice, while no total unspecified acceleration and / or deceleration of the cart 8 along the trajectory 7 is required, slight specified acceleration and / or deceleration may still occur due to the specified motion scheme.

[0074] Considering the above, if a cart 8 is moving along the task assignment section 16 when a package 3 is detected by the sensor 15, the control unit 10 controls such cart 8 to perform the above-mentioned task. In this case, for the same circulation of that cart 8 along the track 7, that cart 8 actively moves along the task section 13, thus receiving an opening device 2 at the receiving station R, glue is applied on the opening device 2 carried by that cart 8, and that cart 8 attaches the respective opening device 2 onto the previously detected package 3.

[0075] Therefore, the control unit 10 is further configured to associate a detected package 3 with a respective cart 8 moving along the task assignment section 16 when that package 3 is detected, such that the cart 8 performs all operations on the detected package 3 (FIG. 2).

[0076] If the cart 8 traverses the entire task allocation section 16 but no package 3 is detected by the sensor 15 in the meantime, e.g. due to the random pitch at which the package 3 is advanced by the linear conveyor 6a, the cart 8 is controlled by the control unit 10 to move inactively along the entire track 7, i.e. the cart 8 does not perform any task and therefore no operation (Figure 3).

[0077] The above arrangement allows the cart 8 to advance along the track 7 in a continuous manner, i.e. without the need to actively accelerate or decelerate the cart 8 relative to the position of the package 3 along the linear conveyor 6a.

[0078] In fact, the carts 8 do not substantially accelerate or decelerate along the trajectory 7. Instead, the carts 8 are merely assigned tasks or not assigned tasks in relation to their presence in the task assignment section 16 while packages 3 are detected by the sensor 15.

[0079] As mentioned above, the cart 8 continues to move forward along the trajectory 7 with a predetermined slight acceleration or deceleration according to a predetermined motion scheme.

[0080] This improves the overall dynamics of the carts 8 along the track 7 and also prevents any unwanted collisions between the carts 8 .

[0081] It further ensures that a detected package 3 will always be handled by the "first" available cart 8 passing through the task assignment section 16 at the time the package 3 is detected.

[0082] Advantageously, the task assignment section 16 is appropriately narrow so that only one cart 8 moves, i.e., advances, along the task assignment section 16 at a time.

[0083] Thus, the task assignment partition 16 has an extension that is smaller than the extension of the temporary partition 14, specifically the extension of the temporary partition 14 in which the task assignment partition 16 is located.

[0084] Preferably, the packages 3 are advanced by a linear conveyor 6a with a predefined minimum distance between them, for example by means of known spacer devices arranged upstream of the detection station D.

[0085] More specifically, the packages 3 arrive at the detection station D with a predefined minimum distance between them.

[0086] This prevents any collisions between the carts 8 which may occur due to two successive carts 8 relating to two successive packages 3 being very close to each other.

[0087] The operation of unit 1 will be described below with reference to a single cart 8 proceeding along track 7, starting from the condition that such cart 8 is positioned upstream of task assignment section 16 and the packages 3 are advanced by linear conveyor 6a and positioned upstream of detection station D.

[0088] When the package 3 arrives at the detection station D, the package 3 is detected by the sensor 15 .

[0089] At the same time, the control unit 10 controls the cart 8 moving along the task allocation section 16 to perform the above tasks and therefore controls the cart 8 to perform the operation, i.e., attaching each opening device 2 onto the detected packages 3.

[0090] In practice, the control unit 10 associates such a cart 8 with a detected package 3 (FIG. 2).

[0091] If a cart 8 is moving along the task assignment section 16 but no package 3 is detected during that time, for example due to the random pitch with which the package 3 is advanced, then there is no task to assign to that cart 8 (FIG. 3).

[0092] However, as described above, the cart 8 continues to move forward along the track 7 according to the predetermined motion scheme.

[0093] Once each cart 8 has passed downstream of the mounting station A, the cart 8 is again advanced towards the task assignment section 16 to begin another cycle.

[0094] The advantages of the unit 1 and the method for controlling multiple carts 8 moving independently along a track 7 according to the invention will be apparent from the above.

[0095] In particular, the above described configuration and control method allows the cart 8 to advance along the trajectory 7 in a continuous manner, i.e. without the need to actively accelerate or decelerate the cart 8 as a whole in relation to the position of the package 3 along the linear conveyor 6a. In fact, the cart 8 is controlled to move along the trajectory 7, i.e. along the task section 13 and the temporary section 14, without performing any task, in case the cart 8 is an unassigned cart according to the above described situation. Thus, the distribution of the cart 8 along the trajectory 7 remains substantially constant, even when no package 3 is present or detected by the sensor 15. In other words, the cart 8 can continue to advance along the trajectory 7 with a substantially predetermined speed profile.

[0096] This increases the overall dynamics of the cart 8 along the track 7 .

[0097] Furthermore, thanks to the above described configuration and control method, the unit 1 is able to automatically adapt the throughput of the packages 3 fed to the transport means 6 .

[0098] In fact, the unit 1 is independent of the pitch at which the package 3 is supplied.

[0099] Obviously, modifications may be made to unit 1 as described herein, but without departing from the scope of protection as defined in the appended claims.

[0100] In particular, the method for controlling according to the present invention can be implemented on any suitable unit including a plurality of carts independently movable along an endless track, the carts configured to perform at least one task to perform at least one operation on an item.

Claims

1. A method for controlling a plurality of carts (8) movable independently of one another along a track (7) and configured to perform at least one task to perform at least one operation on each of the objects (3), comprising the steps of: a) advancing said cart (8) along said track (7), said track (7) including at least one task section (13) and at least one temporary section (14); b) advancing each cart (8) along a task assignment section (16) of said track (7) located upstream of said at least one task section (13); c) advancing a plurality of said articles (3) along a feed path (Q) and through an operation station (A) where said operation is performed; d) detecting the presence or absence of each article (3) at a detection station (D) in said feed channel (Q) located upstream of said operating station (A); e) controlling each cart (8) to perform said at least one task if an item (3) is detected during said detecting step d) as said carts (8) move along said task allocation section (16); Said step e) of controlling comprises the steps of: g) if in said step d) of detecting, said cart (8) is not assigned any task if said item (3) is not detected at said detection station (D) when said cart (8) is moving along said task allocation section (16); method.

2. 2. The method of claim 1, wherein the advancing step a) comprises continuing to advance the cart (8) along the track (7).

3. 3. The method according to claim 1 or 2, wherein the advancing step c) is performed by advancing a plurality of said articles (3) along said feed path (Q) at a random pitch.

4. 4. The method according to claim 3, wherein said advancing step c) is carried out by advancing a plurality of said articles (3) along said feed path (Q) with a predetermined minimum distance between each other.

5. The method according to any one of claims 1 to 4, wherein the advancing step b) is performed by advancing one cart (8) at a time along the task assignment section (16).

6. Said step e) of controlling comprises the steps of: The method according to any one of claims 1 to 5, further comprising: f) associating the detected item (3) with the respective cart (8) moving along the task assignment section (16) when the detected item (3) is detected, such that the cart (8) performs the operation on the detected item (3).

7. The method is carried out in a unit (1) for applying an opening device to the article (3), the article (3) being a sealed package containing a pourable product, if the package is not detected by the sensor (15) at the detection station (D) while the cart (8) is moving along the task assignment section (16), the control unit (10) prevents the assignment of any task to the cart (8); While no task is assigned to the cart (8), the cart (8) continues to move forward along the track (7) and does not perform any task. The method according to any one of claims 1 to 6.

8. The method according to any one of the preceding claims, wherein the length of the task allocation partition (16) is less than the length of the temporary partition (14).

9. The at least one task performed by the cart (8) comprises: receiving and / or picking up opening devices (2) from a receiving station (R) located along the track (7) downstream of the task allocation section (16); applying and / or determining a glue application onto said opening device (2) at a glue application station (G) arranged along said track (7) downstream of said receiving station (R); affixing the opening device (2) previously received by the respective cart (8) and previously coated with glue onto an article (3) adapted to contain a pourable product at a mounting station (A) downstream of the gluing station (G); or The method according to any one of claims 1 to 8, which can be selected from among the above combinations.

10. the cart (8) is provided with a gripping device for receiving an opening device (2) from a receiving station (R) arranged along the track (7) downstream of the task assignment section (16); the gripping device attaches the opening device (2) onto the article (3) at an attachment station (A) arranged downstream of the receiving station (R); The method according to any one of claims 1 to 6.

11. a control unit (10) for controlling each of the carts (8) to perform the at least one task when the item (3) is detected by a sensor (15) and the carts (8) are moving along the task assignment section (16); the control unit (10) prevents the assignment of any task to the cart (8) if the item (3) is not detected by the sensor (15) when the cart (8) is moving along the task assignment section (16); The method according to any one of claims 1 to 6.

12. the carts (8) continue to move according to a predefined speed and acceleration scheme imposed by the control unit (10), and the carts (8) not assigned any task accelerate and / or decelerate along the trajectory (7) as they would if assigned the task; The method of claim 11.

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