Method for monitoring the condition of a moving member in a linear motor system, corresponding linear motor system, forming assembly and computer program product - Patents.com

Abstract

A method for monitoring the condition of a movable member in a linear motor system is described, the method comprising: providing a linear motor system having a track (1) and at least one movable member (2) coupled to the track (1) and configured to move along the track (1), the movable member (2) having a vibration sensor (22) thereon, the method comprising: - placing the movable member in a monitoring area of ​​the track (1); - applying vibration to the movable member; and - detecting a response of the movable member to the vibration by the vibration sensor (22).

Description

[Technical field]

[0001] The present invention relates to a linear motor system including one or more tracks and a moveable member coupled thereto, and to a method for monitoring the condition of such a moveable member. The linear motor system according to the invention may be used in industrial applications, for example in forming assemblies for forming a plurality of objects, such as packaging assemblies configured to form and seal a plurality of packs containing pourable products, in particular pourable food products. [Background technology]

[0002] Linear motor systems are known and used in industrial applications to improve efficiency and flexibility. Such linear motor systems include multiple moveable members that are independently movable about one or more tracks. For example, a linear motor system may include independent carts that are movable along a racetrack.

[0003] For example, it is known to use forming assemblies such as packaging assemblies comprising a plurality of movable members movable independently of one another on a track and configured to form and / or seal objects such as packages made of sterile packaging material configured to contain pourable food products such as fruit juice, UHT (ultra-high temperature treated) milk, wine, tomato sauce, etc.

[0004] These packages are usually produced in fully automatic packaging assemblies, where a continuous tube is formed from a web of packaging material fed into such packaging assembly. To obtain the final package, the web is folded longitudinally and sealed to form a tube which is fed along a vertical direction. The tube is then filled from above with the sterilized food product, sealed and then cut along equally spaced cross sections.

[0005] While known linear motor systems are functionally effective, there remains room for further improvement. For example, a need is felt to monitor the condition of a moving member in a linear system, such as the coupling of the moving member to the track and / or the condition of an element that moves relative to the moving member.

[0006] Condition means the condition of the moving part or its elements with regard to its appearance, quality and order of operation.

[0007] In this way, correct operation of the moving parts throughout their life is facilitated. Indeed, as with any mechanical system, all components are subject to mechanical play, which can reduce the overall stiffness and therefore the repeatability of the entire system. Thus, in forming assemblies, a need is felt to detect early degradation of performance so that the machine operator can take corrective action before, for example, forming errors or sterility problems occur. Summary of the Invention [Problem to be solved by the invention]

[0008] It is therefore an object of the present invention to provide a method for monitoring the condition, e.g. the state and / or the quality and / or the operating sequence, of a moving member in a linear motor system, which allows one or more of the above mentioned needs to be easily achieved in a simple and cost-effective manner. Such an object is achieved by a method and a corresponding linear motor system having the features set forth in the following claims.

[0009] Such objectives can be achieved by a forming assembly for forming one or more objects, such as 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.

[0010] Such an object can be achieved by means of a computer program product which can be loaded into the memory of at least one electronic control unit, e.g. a system control unit and / or a processing unit and / or a processing unit of a movable member, and which comprises software code portions for performing the steps of the methods according to one or more embodiments.

[0011] The disclosed embodiments may achieve, for example, one or more of the following advantages: The condition of the moving members and / or relatively moving parts can be monitored during the life of the linear motor system; Such monitoring may help reduce rejection; and / or -Defects and damage to mechanical moving parts, such as play caused by aging or parts sticking, can be detected at an early stage.

[0012] Any play in a mechanical system can affect the molding performance and reduce the repeatability and accuracy of the entire molding process. If such play is not monitored, it can lead to molding defects. [Means for solving the problem]

[0013] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram of a linear motor system according to one or more embodiments; [Diagram 2] 1 is a non-limiting example of vibrations that may be applied to moving members of a linear motor system. [Diagram 3] FIG. 4 is a schematic diagram of the measured frequency response of a movable member. [Figure 4] FIG. 2 illustrates a schematic front view, with parts removed for clarity, of a packaging assembly for forming multiple sealed packs according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] FIG. 1 illustrates an example of a linear motor system according to one or more embodiments. An arrangement of permanent magnets and coils, i.e., a movable member and respective tracks, defines this type of linear motor and is configured to independently control the movement of the movable member along each track, in a known manner. The tracks may include a single rail or multiple rails. The rails may be closed or open in a racetrack configuration, as illustrated in FIG. 1.

[0016] A linear motor system comprises one or more tracks 1, e.g., a single track in Fig. 1 for simplicity, and one or more movable members 2, preferably movers or carts, coupled to the track 1 and configured to move along the respective track 1. In Fig. 1, the movable members 2 travel along the track 1 in a first direction X, illustrated by an arrow. For example, the track 1 defines an infinite path along which the movable members 2 are configured to move in a cyclical manner.

[0017] The linear motor system further comprises a system control and processing unit 3 configured to position the movable member 2 in a monitoring region M of the track 1 and to apply vibrations to the movable member 2. The system control and processing unit 3 may be disposed on the track 1. The movable members 2 in the system may include respective processing units 20 which may be, for example, wirelessly coupled to the system control and processing unit 3.

[0018] For example, the processing unit 20 in the movable member 2 may be configured to transmit data to the system control and / or processing unit 3 during each cycle as the respective movable member 2 passes therethrough. The transmission of data between the movable member 2 and the system control and / or processing unit 3 may be performed by a wireless (e.g. low energy) transmission module, for example a Bluetooth® low energy transmission module.

[0019] For example, the monitoring region M may comprise a straight region, e.g. a flat portion, of the trajectory 1 extending in a second direction Y perpendicular to the gravitational acceleration direction G.

[0020] For example, the monitoring area M may be the area in which the movable member 2 lies when no force is applied to the movable member 2 by the linear motor system, e.g. by a magnetic coil. In other words, as illustrated in Fig. 1, the monitoring area M may be the area at the bottom of the track 1. Additionally or alternatively, the monitoring area M may be at the top of the track 1.

[0021] The movable members 2 may further include one or more vibration sensors 22 configured to detect a response of each movable member 2 to vibrations applied thereon. The vibration sensors 22 may be disposed on the movable members 2.

[0022] The processing units 3 and / or 20 may be configured to identify faults or errors, for example at an early stage, as a function of the response to vibrations measured by the one or more vibration sensors 22 .

[0023] If a fault or error is identified, the processing unit 3, 20 is configured as follows: -generating an alert indicating the detected error; and / or - preventing the movement of the movable member 2;

[0024] The linear motor system may include a user interface configured to display the warning signal.

[0025] In one or more embodiments, the vibration sensor 22 may comprise at least one inertial sensor, and preferably one or more motion sensors, such as (3D) acceleration sensors, and / or one or more rotation sensors, such as (3D) gyroscopes. Measurements of the inertial sensors may be indicative of the acceleration of the movable member 2. Vibrations may be detected based on such measurements.

[0026] Additionally or alternatively, the vibration sensor 22 may comprise a position error sensor and / or a torque sensor.

[0027] For example, the vibration sensor 22 may be embedded in epoxy resin and fixed to the movable member 2. Advantageously, in this way the inertial sensor may be rendered substantially water-proof and shock-proof.

[0028] Thus, one or more embodiments may relate to a method for monitoring a condition, such as a state and / or a quality and / or an operating sequence, of a moving member in a linear motor system as described above. The method comprises: - positioning the mobile element in the monitoring area M of the track 1, for example in the flat area at the bottom of the track 1 as illustrated in FIG. subjecting the movable member 2 to vibrations, for example one or more vibrations of different frequencies, A vibration sensor 22 detects the response of the movable part 2 to vibrations.

[0029] 2, the step of applying vibrations to the movable member 2 may include applying one or more predetermined (e.g. sinusoidal) motion profiles S1, S2 to the movable member 2. The motion profiles may include, for example, sinusoidal waves S1, S2 having predetermined frequencies f1, f2 and / or amplitudes A1, A2, which may vary over time.

[0030] For ease of understanding, the motion profile illustrated in the figures is a sinusoidal motion profile, however, different, more complex motion profiles having higher frequencies can also be applied.

[0031] 2 illustrates a motion profile over time t of a movable member 2 undergoing periodic vibrations having a first frequency f1 and a second frequency f2 different from the first frequency. Additionally or alternatively, the motion profile may comprise sinusoidal waves having a first amplitude A1 and a second amplitude A2, respectively, the second amplitude being different from the first amplitude A1.

[0032] In one or more embodiments, the method may include applying a plurality of vibrations to the movable member 2, the vibrations having different frequencies, preferably between 0.5 Hz and 200 Hz. Thus, the method may include applying a (e.g. sinusoidal) motion profile to the movable member 2, the motion profile may include one or more frequencies f1, f2, preferably between 0.5 Hz and 200 Hz. In this way, a frequency sweep may be performed at a plurality of different frequencies. In other words, a plurality of vibrations, each having a different frequency, may be applied to the movable member 2.

[0033] 3 illustrates a measure of the response R to a vibration applied to the movable member 2. In particular, this measurement includes the amplitude A of the resonance of the movable member 2 with respect to frequency f. That is, one or more vibrations of different frequencies may be applied to the movable member 2 and its response R over the frequency range f may be measured and plotted.

[0034] The method may include: - comparing the detected response R, for example the response R plotted in FIG. 3, with a predetermined vibration pattern; - checking whether the response R differs from a predefined vibration pattern; If the response R substantially corresponds to the predetermined vibration pattern, then resuming the movement of the movable member 2.

[0035] The predetermined vibration pattern may include a predetermined good condition frequency pattern or a mathematical / theoretical model.

[0036] At installation, vibrations may be applied to each movable member 2 to determine the predetermined vibration pattern. In other words, the method may include calibrating the movable members 2 at installation by subjecting the movable members 2 to one or more vibrations, for example frequency sweeps, to generate the predetermined vibration pattern. Additionally or alternatively, the predetermined vibration pattern may be based on a standard response of a particular type of movable member 2 to vibrations.

[0037] The step of checking whether the response R differs from the predefined vibration pattern may include checking whether new resonances are plotted, e.g. whether new amplitudes A are plotted at frequencies f that are not present at said frequencies f in the predefined vibration pattern. Additionally or alternatively, the step of checking whether the response R differs from the predefined vibration pattern may include checking whether the plotted resonances differ for the predefined vibration pattern by more than a predefined amount, e.g. whether one or more amplitudes A vary by more than a predefined amount at a particular frequency f relative to the amplitudes A at said particular frequency f in the predefined vibration pattern.

[0038] Therefore, if the change in the amplitude A is negligible, the response R substantially corresponds to the predetermined vibration pattern. In other words, if the change in the amplitude A for the predetermined vibration pattern is within a predetermined amount, the response R substantially corresponds to the predetermined vibration pattern. In this way, it is possible to monitor the state of the movable member 2 while taking into consideration noise caused by the measurement of vibration.

[0039] If the responses R substantially match, the method may include resuming operation of the moveable members 2. If there are multiple moveable members 2, the condition measurements may be applied to all moveable members 2 before resuming normal operation.

[0040] If one or more of the movable members 2 indicate that the response R does not substantially correspond to the predetermined vibration pattern, the method may include sending a warning to a user interface and / or preventing resumption or further movement of the movable members 2.

[0041] In one or more embodiments, the method may be applied periodically, i.e., the method may include periodically interrupting operation of the linear motor system to monitor the condition of the movable member 2. For example, normal operation of the linear motor system may be interrupted every 500 hours to monitor the condition of the movable member 2.

[0042] Advantageously, the method according to one or more embodiments allows for accurate monitoring of the condition of the movable member 2 and its parts. For example, during operation, one or more elements of the movable member 2 may be configured to move relative to the body of the movable member 2. Such movement may cause play and / or deterioration in the movable elements over time. Such play and / or deterioration may be detected by means of examining the frequency response of the movable member 2 to vibrations. Indeed, the play and / or deterioration may generate new / different movements of the movable member 2 when required.

[0043] As shown in Fig. 4, one or more embodiments refer to a forming assembly 7 configured to form one or more objects 80. In the following, a non-limiting example of a packaging assembly 7 is shown, configured to form and seal a plurality of packs 80 containing a pourable product, preferably a pourable food product, starting from a tube 8 of packaging material. In the following, reference is made to a packaging assembly 7, but only as a non-limiting example for the sake of clarity and brevity. There may also be different types of forming assemblies 7 that are not packaging assemblies. All the features described below, even if they relate to a packaging assembly 7, can be applied more generally to a forming assembly 7.

[0044] The tube 8 is formed in known manner by longitudinally folding and sealing a web of packaging material (not shown). The tube 8 is then filled with pourable product from above by a pipe (not shown) and fed through the packaging assembly 7 along a linear travel direction X. In particular, the tube 8 extends along a linear longitudinal, e.g. vertical, axis parallel to the direction X.

[0045] The forming assembly 7, e.g. the packaging assembly 7, comprises a linear motor system according to one or more embodiments as described above. The packaging assembly 1 is configured as follows: a pair of conveyors 70 arranged at a distance from each other on either side of the tube 8 and adapted to cooperate with the tube 8; an exit conveyor 72 arranged below the conveyor 70 in a staggered manner relative to the axis X;

[0046] Each conveyor 70 substantially comprises an endless track 1 and a plurality of movable members 2, preferably movable members, coupled to a respective one of the tracks 1 and cyclically movable along the respective one of the tracks 1. Each movable member 2 is configured to slide cyclically along the track 1 of the respective conveyor 70. The plurality of movable members 2 slide along the respective track 1 in use.

[0047] The forming assembly, for example the packaging assembly 7, comprises: a pair of endless tracks between which the tube 8 is fed along a (for example linear) forward direction X; a pair of movable members 2 each movably connected to one of the tracks 1 and movable to move periodically along the tracks 1; a processing unit 3 configured to position the movable member in a monitoring region M of the track 1 and to apply vibrations to the movable member 2;

[0048] The movable member 2 is provided with a vibration sensor 22 arranged to detect the response of the movable member 2 to vibrations applied thereon.

[0049] As shown in Figure 4, the two tracks 1 define respective endless paths P, Q located on opposite sides of the tube 8. More specifically, the paths P, Q include: - respective, preferably linear, actuating branches P1, Q1 along which a tube 8 is provided and along which a movable member 2 cooperates with the tube 8; - a respective return branch P2, Q2 along which the movable member 2 is disconnected from the tube 8;

[0050] According to this preferred embodiment, the paths P, Q are substantially elliptical.

[0051] In use, when sliding along the respective actuating branches P1, Q1, each movable member 2 cooperates with a corresponding movable member 2, i.e. the movable members 2 cooperate with each other two by two, thus defining a pair of movable members 2 which oppose each other, cooperate with each other and cooperate with the tube 8 while sliding along the actuating branches P1, Q1.

[0052] Each pair of movable members 2 is configured to cooperate with the tube 8 to cyclically form and seal one puck 80 at a time, and cut the puck 80 to separate it from the tube 8, as shown in FIG.

[0053] For this purpose, each mobile member 2 comprises, on one side thereof, a forming unit 202 and a sealing unit 204 arranged to cooperate with the tube 8 along the respective working branch P1, Q1.

[0054] The forming units 202 are configured to cooperate with respective tube portions 82 of the tubes 8 to form at least a corresponding pack portion, more particularly a corresponding pack 80. For this purpose, each forming unit 202 is preferably movably mounted by a respective movable member 2. The forming units 202 preferably present a C-shaped cross-section and may comprise a half-shell consisting of a rear wall 208 and a pair of lateral flaps 210. In the illustrated embodiment, the flaps 210 are movably connected to the wall 208. The flaps 210 project from and are hinged to opposite lateral edges of the wall 208 when the movable member moves along the operating branches P1, Q1.

[0055] In use, the half shells of each forming unit 202 are configured to sequentially and cyclically contact and cooperate with the tube portions 82 to form at least a pack portion of a respective pack 80 .

[0056] Each half-shell is linearly movable transversely, for example orthogonally, to the direction X, i.e. along the direction Y, towards the tube 8, i.e. towards the tube part 82 which it has to form. Each forming unit 202 comprises a mobile element 207 linearly movable along the direction Y, which mobile element carries the respective half-shell.

[0057] The sealing unit 204 is configured to cooperate with the tube 8 to seal the tube portions 82 at successive cross sections transverse to the direction X at predetermined equal intervals. Furthermore, the sealing unit 204 is configured to cooperate with the tube 8 to cut the packs 80 at the cross sections to separate the packs 80 from one another.

[0058] On the one hand, each sealing unit 204 is mounted downstream of the corresponding forming unit 202 of the respective movable member 2 along the respective path P, Q and comprises a counter-sealing device and a removable cutting element, for example a knife (not shown). On the other hand, each sealing unit 204 is mounted downstream of the corresponding forming unit 202 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. The sealing device may comprise an ultrasonic sealing device, an induction heating sealing device or an induction heating sealing device.

[0059] As shown in FIG. 4, when the forming unit 202 and the sealing unit 204 are advanced by the respective movable members 2 along the respective operational branches P1, Q1, the respective half shells, sealing devices and counter-seal devices move back and forth along the direction Y between: a closed or operative position in which the half shells, the sealing device and the counterseal device cooperate with the respective tube portions 82 to form, seal and sever the respective packs 80; An open or idle position in which the half shells, sealing devices and counterseal devices are removed from the tube 8 or from the formed pack 80.

[0060] When the half shells are in the operative position (closed position), the flap 210 of each half shell rotates about its respective hinge, for example about an axis parallel to the direction X, from a position away from the respective wall 208 to a position substantially perpendicular to the wall 208, facing the flap 210 of the other half shell carried by the corresponding movable member 2 of the same pair, and contacts the tube 8 to completely surround the respective tube portion 82 destined to form the respective pack 80.

[0061] When the two half shells of the two respective forming units 202 of a pair of cooperating movable members 2 are together in the operating position (closed position), they define a substantially prismatic cavity and accordingly control the volume and shape of one respective puck 80 being formed.

[0062] When the counterseal device and the sealing device of the pair of cooperating movable members 2 are in the operative (closed) position, they cooperate with each other to heat seal the tube 8 to form upper and lower sealing bands, and then the respective cutting elements are removed to cut the packs 80 between the upper and lower sealing bands of two adjacent packs 80, separating the formed packs 80 from each other.

[0063] Further movement occurs between the sealing unit 204 and the forming unit 202 along direction X to form the top and / or bottom of the pack 80, as illustrated in FIG.

Claims

1. A method for monitoring the state of a movable member (2) in a linear motor system comprising an orbit (1) and at least one movable member (2) coupled to the orbit (1) and configured to move along the orbit (1), wherein the movable member (2) is provided with a vibration sensor (22) thereon, and the method comprises: - Placing the movable member (2) in a monitoring area (M) of the orbit (1); - Applying vibration to the movable member (2); - Detecting, by the vibration sensor (22), a response (R) of the movable member (2) to the vibration. A method comprising the above.

2. - Comparing the detected response (R) with a predetermined vibration pattern; - Checking whether the response (R) is different from the predetermined vibration pattern; - Resuming the operation of the movable member (2) when the response (R) substantially matches the predetermined vibration pattern. The method according to claim 1.

3. When the response (R) does not substantially correspond to the predetermined vibration pattern, comprising sending a warning to a user interface and / or preventing the resumption of the operation of the movable member (2). The method according to claim 2.

4. Applying vibration to the movable member (2) includes applying a sinusoidal motion profile (S1, S2) to the movable member (2). The method according to claim 1.

5. The monitoring area (M) includes a linear area of the orbit (1) extending in a direction perpendicular to the direction of gravitational acceleration (G). The method according to claim 1.

6. Including applying a plurality of vibrations to the movable member (2), the vibrations having different frequencies (f1, f2). The method according to claim 1.

7. Including periodically interrupting the operation of the linear motor system to monitor the state of the movable member (2). The method according to claim 1.

8. Including calibrating the movable member (2) during installation by applying at least vibration to the movable member (2) to generate a predetermined vibration pattern. The method according to claim 1.

9. A computer program loadable into the memory of at least one electronic control unit (3, 22) and including a software code portion for executing the steps of the method according to claim 1.

10. - A track (1); - At least one movable member (2) coupled to the orbit (1) and configured to move along the orbit (1); - A processing unit (3) configured to position the movable member in the monitoring region (M) of the track (1) and apply vibrations to the movable member (2); comprising; The movable member (2) comprises a vibration sensor (22) configured to detect the response of the movable member to vibrations applied thereto. Linear motor system.

11. The monitoring region (M) includes a region where the movable member (2) lies when no force is applied to the movable member (2) by the linear motor system. The linear motor system according to claim 10.

12. The vibration sensor (22) includes at least one inertial sensor and / or a position error sensor and / or a torque sensor. The linear motor system according to claim 10 or 11.

13. The vibration sensor (22) is embedded in an epoxy resin and fixed to the movable member (2). The linear motor system according to claim 10.

14. A forming assembly (7) configured to form a plurality of packages (80) and comprising the linear motor system according to claim 10, the forming assembly (7) comprising: A pair of endless tracks (1); A pair of movable members (2), each movable member (2) being movably coupled to one track (1) and being movable periodically along the one track (1); A processing unit (3) configured to position the movable member in the monitoring region (M) of the track (1) and apply vibrations to the movable member (2); comprising; The movable member (2) comprises a vibration sensor (22) configured to detect the response (R) of the movable member to vibrations applied thereto. Forming assembly (7).

15. A packaging assembly configured to form and seal a plurality of packs (80) containing pourable products starting from a tube (8) of packaging material, the packaging assembly comprising: A pair of endless tracks (1) along which the tube (8) is fed in a linear forward direction (X). Each forming unit (202) and each sealing unit (204) which are each linearly movable in a lateral direction with respect to the forward direction (X) toward the tube (8) so as to periodically cooperate in contact with a continuous tube portion (82) such that each of the pair of movable members (2) forms and seals at least corresponding pack portions of respective packs (80). The forming assembly (7) according to claim 14.

Images