Patent Application
20240317513
The present invention relates to linear motor systems comprising one or more tracks and movable members coupled thereto. The linear motor system according to the instant invention may be used in industrial applications, e.g. in a forming assembly for forming a plurality of objects such as a packaging assembly configured to form and seal a plurality of packs containing pourable products, in particular pourable food products.
Linear motor systems are known and used in industrial applications to improve efficiency and automation. Linear motor systems comprise a plurality of movable members movable, independently from each other, on one or more tracks. For example, it is known the use of forming assemblies such as packaging assemblies comprising a plurality of carts movable independently from each other on tracks and configured to form and seal packages made of sterilized packaging material configured to receive pourable food products, such as fruit juice, UHT (ultra-high temperature-treated) milk, wine, tomato sauce, etc.
These packages are normally produced in fully automatic packaging assemblies, in which a continuous tube is formed from a web of packaging material fed to such packaging assembly. To obtain the final package, the web is folded and sealed longitudinally to form the tube, which is fed along a vertical advancing direction. The tube is then filled with the sterilized food product from above and is sealed and subsequently cut along equally spaced transversal cross sections.
Although being functionally valid, the known linear motor systems are still open to further improvement.
Currently, monitoring a correct handling of the packages may be done by checking the final shape of the package by the operator or by positioning a position error sensor connected to a system control and/or processing unit which is configured to check—at each handling cycle—whether the carts are positioned at the correct position at the correct time. However, the need is felt for a more automatic method of checking errors in the handling and/or to have direct measurements of the handling, i.e. forming and sealing, process while it is performed.
A need is felt for a synchronization of the movable members which may improve the correct operation of the linear motor system and the forming system comprising the linear motor system. For example, in use in a packaging assembly, a synchronization of the data received from sensors mounted on the movable members may facilitate detection of incipient failures or deviations from nominal behavior. If the movable members in the system are not synchronized, the measures detected by the sensors placed on the movable members may be imprecise.
It is therefore an object of the present invention to provide a linear motor system, which can facilitate achieving one or more of the above-mentioned needs in a straightforward and low-cost manner. Such an object is achieved by means of a linear motor system and a corresponding method having the features set forth in the claims that follow.
Such an object may be achieved by means of a forming assembly for forming one or more objects, e.g. a packaging assembly for forming and sealing a plurality of packs, the forming assembly comprising a linear motor system according to one or more embodiments.
Thanks to the invention, the processing unit of a movable member is able to acquire data from one or more sensors and transmit it to a system control and/or processing unit, with the data being timestamped to a synchronized timestamp and not to an uncorrelated local microcontroller time. That is, thanks to the instant solution, it is possible to correlate the on-board data of the movable members (e.g. accelerations or forming profile in a packaging assembly) with the off-board data (data from a system control and/or processing unit).
The disclosed embodiments achieve one or more advantages, e.g. the timestamps of the different movable members in the system may be synchronized and/or the measurements of sensors mounted on the movable members can be similarly synchronized.
Embodiments of the present invention will be described by way of example with reference to the accompanying drawings, in which:
The linear motor system comprises:
For example, the track 1 defines an endless path on which the movable members 2 are configured to move cyclically.
The processing unit 22 of each movable member 2 comprises an internal clock that can be adjusted by means of the synchronization signal S, e.g. received at a predetermined synchronization position of the track 1.
The calculations of the processing unit 22 and/or operations of the movable member 2, following the adjustment of the internal clock, may be extremely precise position-wise. This way, any data exchanged between the movable members 2 and/or with a system control and/or processing unit may be synchronized.
In one or more embodiments, one or more movable members 2 may each comprise one or more sensors 24 configured for detecting a physical quantity of the movable member 2 or part thereof. For example, the physical quantity may comprise a movement of the movable member 2 or part thereof that may be indicative of a position of the movable member 2 or parts thereof in the linear motor system. It will be appreciated that, even though herein reference is made to a movement sensor for simplicity, different sensors may be present, e.g. measuring different physical quantities that may be useful for improving a quality of operation of the movable members 2 of the linear motor system.
The processing unit 22 may be configured to:
In one or more embodiments, the processing unit 22 is configured to reset the internal clock at the reception of the synchronization signal S, e.g. when the synchronization signal S is received.
For example, the system may comprise a system control and/or processing unit 5, at the track 1, that may receive the data from the sensor(s) 24 mounted on the movable members 2, e.g. at each cycle. Advantageously, if the data timestamps are synchronized between the different movable members 2 and/or with the system control and/or processing unit 5, a precise control of the position and/or condition of the movable members 2 is possible. This way, errors in operation of the movable members in the system may be reduced. The transmission of data between the movable members 2 and the system control and/or processing units 5 may occur by means of low-energy wireless transmission modules, e.g. Bluetooth low-energy transmission modules.
The system control and/or processing unit 5 may be configured to receive the data from a movable member 2 and correct the timestamps thereof. If the internal clock of the movable member 2 processing unit 22 is reset at each cycle, the data timestamps begin at time 0 s. Accordingly, the system control and/or processing unit 5 may be configured to sum to the timestamps of the data a predetermined amount corresponding to the time at which the synchronization signal S is transmitted, preferably compensated of a reception delay. For example, the system control and/or processing unit 5 may send the synchronization signal S at 2 ms to a specific movable member 2. The data received from said movable member 2 has timestamps starting at 0 s. The transmission and reception delay of the synchronization signal S may be 10 μs. Thus, the system control and/or processing unit 5 may correct the timestamps of the data received adding to the timestamps 2 ms+10 μs.
This way, all the data, gathered remotely from each movable member 2, is synchronized in time with the system control and/or processing unit 5.
The predetermined position may comprise a position immediately upstream of the movable member 2 operating region. That is, the internal clock of the movable member 2 may be adjusted or reset instants before the movable member 2 begins its designed automatized operation.
In one or more embodiments, the linear motor system comprises a powering device 4, positioned at the track 1 and couplable, e.g. electrically and/or magnetically, to the movable members 2 to provide power thereto. As depicted in
In one or more embodiments, as illustrated in
The optical sensor may be mounted on a surface 2a of the respective movable member 2. The synchronization device 3 may be positioned at the track 1. The optical signal transmitter may comprise an IR transmitter, e.g. an IR diode, configured to transmit an IR synchronization signal S, and the optical sensor may comprise an IR receiver, configured to detect the IR synchronization signal.
The optical sensor may be configured to detect an optical (IR) synchronization signal S having a predetermined carrier frequency bandwidth, preferably between 10 kHz and 1 MHz, more preferably 20 and 50 kHz, even more preferably 38 kHz. That is, the optical sensor may detect signals only in the predetermined bandwidth. Accordingly, the optical signal transmitter is configured to transmit the synchronization signal S in the predetermined carrier frequency bandwidth. Thanks to such feature, the optical sensor may be robust with respect to different signals with respect to the synchronization signal S and may thus avoid errors.
The system control and/or processing unit 5 may be coupled to and drive the synchronization device 3, which consists of the optical (IR) transmitter. For example, the system may comprise a first detection sensor 6, coupled e.g. directly to the system control and/or processing unit 5, that may detect when a movable member 2 is at the predetermined synchronization position of the track 1. The system control and/or processing unit 5 may be configured for transmitting the synchronization signal S by means of the optical transmitter when the presence of the at least one movable member 2 at the synchronization position is detected.
In alternative, the synchronization device 3 may comprise, in addition to the optical transmitter, a high-speed real-time communication module to receive an enable signal from the system control and/or processing unit 5, indicative of a movable member 2 being detected at the predetermined synchronization position p0. The synchronization device 3 may be configured to transmit the synchronization signal S when said enable signal is received by the synchronization device 3.
The processing unit 22 of the movable member 2 is thus configured to adjust, e.g. reset, its internal clock in the following instants, e.g. units of microseconds after reception of the optical synchronization signal S. The data received by the processing unit 22, following the reception of the synchronization signal S, are sampled and timestamped as a function thereof.
In one or more embodiments, as illustrated in
In one or more embodiments, the powering device 4 may induce a sinusoidal current in the powering module 26. The synchronization sensor 20, e.g. comprising the current sensor, may be configured to detect a first rising edge of the sinusoidal current inducted. The synchronization signal S may be generated at the detection of said rising edge.
As discussed, in one or more embodiments the synchronization signal S is transmitted at a predetermined position p0 and at a predetermined time instant t0 in the cycle of the movable member 2. This way, advantageously, the movable member 2 may receive a precise information of a punctual point in space and time p0, t0 for synchronization of the movable members 2 within the linear motor system. The predetermined position p0 may be transmitted to the processing unit 22 or may be stored within a memory of the processing unit 22.
In addition or in alternative, the movable member 2 may be configured to receive the synchronization signal S, e.g. having a time length T. That is, while the movable member 2 moves along the track 1, the synchronization signal S may be transmitted to the movable member 2 for a predetermined period of time T.
The system may comprise the first detection sensor 6 configured to detect when the movable member 2 is at the first predetermined synchronization position p0 and transmit a first detection signal D1 to the system processing unit 5 as a result thereof. The system control and/or processing unit 5 may be configured to start transmission of the synchronization signal S at a first instant t0 of reception of the first detection signal D1.
The system may comprise a second detection sensor 6 configured to detect when the movable member 2 is at a second predetermined position p1 and transmit a second detection signal D2 to the system processing unit 5 as a result thereof. The system control and/or processing unit 5 may be configured to interrupt, e.g. end or stop, transmission of the synchronization signal S at a second instant t1 of reception of the second detection signal D1.
A distance P between the first and second predetermined position p0, p1 may be predetermined. Such distance P may be stored in a memory of the processing unit 22 of the movable member 2. In alternative, the distance P may be transmitted to the processing unit 22.
The processing unit 22, as a result of the synchronization signal S, may be configured to adjust the internal clock tCLK to a predetermined first time instant tCLK0, e.g. the processing unit 22 may reset the clock at first reception of the synchronization signal S, as illustrated in
The processing unit 22 may be configured to calculate an initial velocity v0 as v0=P/(tCLK1-tCLK0). Advantageously, this way also the initial velocity of the movable member 2 may be precisely calculated. A more correct measure of both velocity and position may as such be possible.
In one or more embodiments, in case the synchronization device 3 comprises, e.g. consists of, the powering device 4, the time length T of the synchronization signal S may be a result of the current I induced in the powering module 26, as illustrated in
For example, the synchronization sensor 20 may be configured to detect the rising edges of the induced current I. The synchronization sensor 20 may be configured to start transmission of the synchronization signal S to the processing unit 22 at a first rising edge, e.g. the first rising edge I1 detected. The synchronization sensor 20 may be configured to interrupt transmission of the synchronization signal S to the processing unit 22 at a second rising edge, e.g. the fourth rising edge 14 detected.
Accordingly, the current sensor may be configured to detect the synchronization signal S as a function of a current present at the powering module 26, e.g. as a function of one or more rising edges I1, I4 of the current I at the powering module 26.
The time length T may be indicative of the distance P that the movable member 2 covers between time instants t0, t1. The distance P may be stored in a memory of the processing unit 22 of the movable member 2.
One or more embodiments, as illustrated in
The packaging material has a multilayer structure (not shown), and comprises a layer of fibrous material, e.g. paper, covered on both sides with respective layers of heat-seal plastic material, e.g. polyethylene.
In the case of aseptic packs 80 for long-storage products, such as UHT milk, the packaging material also comprises a layer of gas-and-light barrier material, e.g. aluminum foil or ethylene vinyl alcohol (EVOH) film, which is superimposed on a layer of heat-seal plastic material, and is in turn covered with another layer of heat-seal plastic material, the latter forming the inner face of the pack 80 eventually contacting the pourable product.
Tube 8 is formed in known manner by longitudinally folding and sealing a web (not shown) of packaging material. Tube 8 is then filled from above by a pipe (not shown) with the pourable product and is fed through packaging assembly 7 along a straight advancing direction X. In detail, tube 8 extends along a straight longitudinal, e.g. vertical, axis parallel to direction X.
The forming assembly 7, e.g. the packaging assembly 7, comprises a linear motor system according to one or more embodiments as described previously. Forming assembly 1 comprises:
Each conveyor 70 substantially comprises the endless track 1 and a plurality of movable members 2, preferably carts, coupled to, and cyclically movable along, one respective track 1. Each movable member 2 is configured to cyclically slide along track 1 of the respective conveyor 70. A plurality of movable members 2 slides, in use, along each track 1.
The forming assembly 7, e.g. the packaging assembly 7, thus comprises:
Each movable member 2 of the pair of movable members 2 comprises a respective forming member 27 and a respective sealing member 28 linearly movable towards the tube 8, transversally to the advancement direction X, to cyclically cooperate in contact with successive tube portions 82, to form and seal at least corresponding pack portions of respective packs 80, respectively.
At least one movable member 2 of the pair of movable members 2 in the assembly comprises a synchronization sensor 20, configured to detect the synchronization signal S, and a processing unit 22 coupled to the synchronization sensor 20 and configured for adjusting an internal clock thereof as a function of the synchronization signal S. For example, the processing unit 22 is configured to reset the internal clock at the reception of the synchronization signal S, e.g. when the synchronization signal S is received.
As illustrated in
According to this preferred embodiment shown, paths P, Q are substantially oval-shaped.
In use, when sliding along the respective operative branch P1, Q1, each movable member 2 cooperates with a corresponding movable member 2—i.e. movable members 2 mutually cooperates two by two—defining in this way a pair of movable members 2 facing each other and cooperating with one another and with tube 8 while sliding along operative branches P1, Q1.
Each pair of movable members 2 is configured to cooperate with tube 8 to cyclically form and seal one respective pack 80 at a time, and cut the pack 80 to separate the pack 80 from tube 8, as shown in
To this end, each movable member 2 comprises, at one of its sides, the forming member 27 and the sealing member 28 both configured to cooperate with tube 8 along the respective operative branches P1, Q1.
As better described below, forming members 27 are configured to respectively cooperate with tube portions 82 of tube 8 to form at least corresponding pack portions, more in particular corresponding packs 80.
For this purpose, each forming member 27 is carried by, preferably mounted on, the respective movable member 2 in a movable manner. The forming member 27 may preferably comprise a half-shell, presenting a C-shaped cross section and comprising a main wall 270 and a pair of lateral flaps 272. In the embodiment shown, flaps 272 are movably coupled to wall 270.
In detail, flaps 270 project from opposite lateral edges of wall 270 when movable members move along operative branches P1, Q1, and are hinged to such edges.
In use, the half-shell of each forming member 27 is configured to sequentially and cyclically cooperate in contact with tube portions 82 so as to form at least pack portions of respective packs 80.
In greater detail, each half-shell is linearly movable transversally, e.g. orthogonally, to direction X, towards tube 8, i.e. towards the tube portion 82 that half-shell has to form.
Each movable member 2 comprises a movable element 274 linearly movable transversally, e.g. orthogonally, to direction X, which carries a respective half shell.
Sealing members 28 are configured to cooperate with tube 8 to seal tube portions 82 at predetermined, equally spaced, successive cross sections crosswise to direction X. Furthermore, sealing members 28 are configured to cooperate with tube 8 to cut packs 80 at the cross sections, to separate packs 80 from one another.
On one side, each sealing member 28 is mounted downstream of the corresponding forming member 27 of the respective movable member 2 along the respective path P, Q and comprises a counter-sealing device and an extractable cutting element, for example a knife (not illustrated). On the other side, each sealing member 28 is mounted downstream of the corresponding forming member 27 of the respective movable member 2 along the respective path P, Q and comprises a sealing device and a seat, adapted to receive the knife of the corresponding sealing device configured to cooperate with such counter-sealing device. Sealing devices may comprise ultrasonic, induction or inductive heating sealing devices.
As shown in
When half-shells are in the operative (closed) position, flaps 272 of each half-shell rotate about the respective hinges from a position in which they diverge from the respective wall 270, to a position in which they are substantially orthogonal to the wall 270, face flaps 272 of the other half-shell carried by the corresponding movable member 2 of the same pair and contact tube 8 to completely surround the respective tube portion 82 destined to form the respective pack 80.
In one or more embodiments, as discussed previously, one or more movable members 2 may comprise one or more sensors 24, e.g. position detectors, mounted thereon and configured for transmitting data indicative of movement of the movable member 2 or parts thereof. For example, the sensors 24 may be positioned at the forming member 27 and/or at the sealing member 28. For example, the sensors 24 may be positioned at the movable parts of the movable members 2, e.g. at the flaps 272, at the wall 270 and/or at the movable element 274 of the forming members 27 and/or at the sealing devices and counter-sealing devices of the sealing members 28. Sensor data timestamps of the sensors 24 may thus be adjusted as a function of the synchronization signal S.
For example, the sensors 24 may be configured to detect a movement of the movable member 2 and/or a movement of a first portion of the movable member 2 configured to perform a relative movement with respect to a second portion of the movable member 2.
In one or more embodiments, the sensors 24 may comprise:
In one or more embodiments, the synchronization device 3 (not illustrated in
The synchronization device 3 may be configured to transmit the synchronization signal S at the beginning of each sealing cycle of a pack 80 in the plurality of packs 80 or at the beginning of each forming and sealing cycle of a pack 80 in the plurality of packs 80.
In one or more embodiments, to provide power to the movable members 2, the forming (e.g. packaging) assembly may comprise a powering device 4, e.g. an electrical pulse generator, as described previously. The powering device 4 may be positioned at the track 1 and may be couplable, e.g. temporarily, to the one or more movable members 2 to provide power thereto. The movable members 2 may be configured to couple to the powering device 4 at a predetermined powering region.
One or more embodiments may relate to a method that may be implemented in a linear motor system as described above. The method comprises:
The method may comprise adjusting the internal clock when the synchronization signal S is detected, i.e. the steps of detecting the signal S and adjusting the internal clock may occur almost simultaneously.
The method may comprise coupling, e.g. temporarily, the powering device 4 to the at least one movable member 2 and providing power to the movable member 2.
The method may comprise:
The optical synchronization signal S may exhibit a predetermined carrier frequency bandwidth, preferably between 20 and 50 kHz, more preferably 38 kHz.
The synchronization signal S may have a predetermined time length T and the method may comprise calculating an initial velocity v0 as a function of the time length T.
The method may comprise:
The method may comprise:
The method may comprise:
For example, the step of detecting the synchronization signal S as a result of the power transfer may comprise detecting when a current is present at the powering module 26 of the movable member 2.
The method may comprise:
In one or more embodiments, the method may comprise:
The steps of transmitting and detecting the synchronization signal S may occur previously with respect to the steps of linearly moving the forming member 27 and the sealing member 28 and forming and sealing. That is, the synchronization signal S may be configured to be transmitted and detected at the beginning of each sealing cycle of a pack 80 in the plurality of packs 80 or at the beginning of each forming and sealing cycle of a pack 80 in the plurality of packs 80.
The steps of transmitting and detecting the synchronization signal S may occur simultaneously with respect to the step of sealing.
The method may comprise, e.g. at each cycle of a plurality of movable members 2 in the linear motor system or forming (e.g. packaging) assembly 7:
In one or more embodiments, the method may comprise:
| Number | Date | Country | Kind |
|---|---|---|---|
| 21189789.7 | Aug 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/069386 | 7/12/2022 | WO |
