A MEASURING UNIT FOR MEASURING THE WEAR OF A REVOLUTIONARY SURFACE OF ROTATING MEMBERS, A MACHINE INCORPORATING SAID UNIT, AND A MEASURING METHOD

Abstract

The measuring unit (11) for measuring the wear of the surface of revolution of the rotating members, said measuring unit comprises: a support structure (13); a rod (15) having a first sliding movement along a direction having a rectilinear component (S1) with respect to the support structure (13); a cam guide (17) having a second relative movement with respect to the sliding rod (15); at least one roller (19a, 19b) rotatably fixed to the sliding rod (15) and in rolling contact with a corresponding track (21a, 21b) of said cam guide (17), whereby said second relative movement between the cam guide (17) and the sliding rod (15) causes the first movement of the rod (15) along said sliding direction (S1);wherein said measuring unit (11) comprises an indicator (23) of the position of said at least one roller (19a, 19b) along said straight component (S1), said indicator being capable of generating an electrical signal indicating the distance (d) between said indicator (23) and said roller.;

Description

The invention relates to a measuring unit for measuring the wear of the surface of revolution of rotating members, a machine incorporating such a unit, and a corresponding measuring unit. BACKGROUND OF THE INVENTION In several technical fields, the use of rotating members is known, rotatably fixed to a motion-transmitting member and in cooperation with a cam guide that defines a non-rectilinear path for the rotating members, by which a first relative movement is imparted between the cam guide and the rotation of the members results in a second sliding movement of the motion-transmitting member, along with a direction that has a substantially rectilinear component. According to this arrangement of the mechanical parts, the rotating members, which typically consist of rotating rollers, move along multiple paths while remaining in contact with a track defined by the cam guide. Consequently, the surface of revolution—that is, the outermost surface of the rollers in contact with this track—wears progressively and proportionally with use and the pressure exerted by the rollers against the track. The sinuosity of the path imposed on the rollers by the guide, the speed at which the rollers slide along the guide track, and the material from which the rollers are made are three parameters that can influence roller wear and, therefore, their service life.Furthermore, the combination of these factors and the variability of the environment in which these machines, which incorporate these mechanical members, operate, makes it difficult to predict the wear state of the rollers based on statistical analyses derived from data collected on the same machine, or on similar machines, over time. A common application of this combination of mechanical components is in container processing machinery, specifically for bottles, such as capping, labeling, and filling machines. Typically, these machines have a carousel comprising a plurality of reciprocating rods or pistons that perform repeated back-and-forth movements at a very high frequency along a substantially straight path. This occurs as the rollers drive the rods along a cam guide that defines a sinuous path for the rollers. In the aforementioned movement, these rods can be guided by pairs of rollers or individual rollers that roll in contact with a corresponding track defined by the cam guide. These rollers are commonly known as cam follower rollers and are rotatably fixed to a yoke integral with the rod. The yoke is guided by the cam follower rollers, which, during normal operation, wear down over time, causing a change in the yoke's vertical position and altering the machine's performance. Document EP1462411 describes an example of a machine of the aforementioned type, which specifically concerns a head for applying aluminum capsules to bottle necks. As is well known, roller wear can lead to imprecise machine operation, increased noise, and decreased overall performance. These problems are particularly critical and undesirable in the bottling industry. Therefore, it is essential to maintain the machine promptly and replace excessively worn rollers with new ones. For this reason, there is also a clear need in several areas of technology to prevent machines of this type from working with worn rollers or in suboptimal conditions. A first problem that must be solved and addressed by the present invention is, therefore, how to notice the beginning of excessive wear conditions in the rollers of machines that use the described movements. Replacing the rollers also inevitably requires stopping the machine's operation and requires considerable intervention time, resulting in economic losses due to downtime and maintenance costs. A second problem that this invention must solve and address is, therefore, how to predict the wear of the rollers, so that, during the same downtime, it is possible to intervene simultaneously on all the rollers that require maintenance, thus avoiding a series of downtimes each time a roller has to be replaced. Currently, according to the previous technique, the diameter of the rollers is measured periodically and at predetermined intervals, depending on the machine's operating hours, thus wasting time and labor. For example, solutions for determining the wear of rotating rollers are known from publication US2019 / 0308820. QQI I ηη / Ρ7Π7 / Β / νΐΛΙ The application described in GB1261644 (A) relates, for example, to a capping machine with a continuously moving conveyor belt, where counter-rotating friction rollers apply a threaded cap to a container on the conveyor. An automatic adjustment mechanism is provided to move the axis of rotation of the friction rollers to compensate for wear on the peripheral rubber portion of the rollers. Therefore, the teaching of this document is limited to a solution for compensating for the gap created by wear on the rubbing portion of a rotating mechanical component, but it does not address the problem of how to diagnose or predict roller wear. An object of the invention is to provide a solution to the problem of how to determine the degree of wear of moving parts, such as rotating rollers, whose mechanical support and guide devices drive the rectilinear movements of machine parts. More specifically, although not excessively, the invention aims to provide a solution to the aforementioned problem that can be applied to cam follower rollers that have the function of guiding the vertical concentrator of vertically moving parts, responsible for carrying out the step of applying closing elements to containers, i.e., to cap or fill containers, particularly bottles. Another object of the invention is to provide a solution to the aforementioned problems, which is reliable and industrially applicable at low cost and, therefore, lends itself to large-scale industrial production. These and other objects are achieved with the measuring unit for measuring the wear of the surface of revolution of rotating members, with the machine incorporating said measuring unit and with the measuring method as claimed in the attached claims. BRIEF DESCRIPTION OF THE INVENTION The objects of the invention are achieved substantially by means of a sensor of the degree of wear of the moving parts that support and guide the mechanical devices that drive the vertical movements of the parts of a machine. In a preferred embodiment, the invention provides a sensor in a stationary position, which sensor measures, in a non-contact manner, the distance of a component connected to the machine roller from the sensor. The signal generated by the sensor is additional and preferably processed by means of a processing algorithm, which has the purpose of providing an indicator of the wear state of each roller present in the machine, in order to indicate the state of QQI I ηη / Ρ7Π7 / Β / νΐΛΙ wear and tear of the same and the possible need for its replacement. The sensor performs an indirect measurement; that is, it detects roller wear by sensing the positional variation of the surface of a machine component, such as a roller support portion, preferably a roller clamping fork. Through this positional variation, the wear of the corresponding roller is detected, and by means of appropriate predictive algorithms, the operation of which will become clearer from the following description, it is possible to predict how the wear of the rotating component will progress and thus indicate in advance the need for replacement. The measuring unit for measuring surface wear, or revolution, or contact surface, or rotating members such as, for example, rollers, needle bearings, cylinders, bushings, etc., according to a preferred embodiment of the invention, comprises mainly: - a support structure or frame; - a rod or piston having a first sliding motion along a direction that has a rectilinear component with respect to the support structure; - a cam guide having a second relative motion with respect to the sliding rod and capable of causing a movement of the rod along said sliding direction; - at least one roller rotatably fixed to the sliding rod and in rolling contact with a corresponding track defined in said cam guide, whereby the second relative movement between the cam guide and the sliding rod causes the first movement of the rod along said sliding direction; According to the invention, said measuring unit comprises an indicator or sensor of the position of said roller along said straight component, said indicator being capable of generating an electrical signal indicating the distance between said indicator and said roller. Preferably, the roller is rotatably fixed to the sliding rod, or piston, at an upper end of the rod, when the rod is mounted vertically relative to the support structure. Preferably, the roller is rotatably fixed to the sliding roller by means of a support fork, and even more preferably, the indicator is capable of generating an electrical signal indicating the distance between the indicator and a portion, or end, of the fork proximal to the indicator, and preferably along the rectilinear component of the sliding direction of the rod. Alternatively, the roller may be rotatably fixed directly to the sliding rod or piston. According to a preferred embodiment of the invention, each rod comprises a pair of rollers rotating about parallel axes, each roller being in bearing contact with a corresponding path defined in said cam guide. According to this preferred embodiment of the invention, both rollers of each roller pair are rotatably fixed to the rod by means of the same fork. Furthermore, the axis of rotation of each roller of said roller pair preferably intersects with said rectilinear component of the sliding direction of the rod. According to the invention, the distance measured by the position sensor is preferably measured parallel to said rectilinear component of the sliding direction of the rod. According to a preferred embodiment of the invention, the measuring unit comprises a plurality of such rods or pistons. Furthermore, and preferably, the sensor is an integral part of the support structure and arranged to measure the distance from the support fork of the rollers of each rod when the rod is vertically aligned with the sensor. In other applications, or according to other arrangements, several sensors may be provided associated with the support structure or with the cam guide. Preferably, this second movement is a cyclical periodic movement, capable of causing a forward and backward movement of said rod. According to the invention, said position sensor is preferably an eddy current-based indicating sensor of the type conventionally used for non-contact measurement of displacements, distances, positions, thicknesses, oscillations and vibrations. Preferably, the measuring unit according to the invention further comprises a counting device, preferably associated with an electronic control unit in which the incoming signals from the position sensor are processed by means of suitable software. The counting device is capable of generating a signal indicating the presence of one of the roller clamping rods. Normally, this rod is referred to as the zero rod, and the signal generated by the counting device after the passage of this zero rod corresponds to the completion of an operating cycle in which all the remaining rods have passed the position sensor. Preferably, the measuring unit also comprises an activator sensor, preferably associated with said electronic unit and capable of generating an indicator signal of the passage of each rod in said activator sensor. According to a particular embodiment of the invention, during the operation of the measuring unit, each rod will pass through the counting device, but preferably only the zero rod equipped with means arranged to interact with the sensor will cause a corresponding signal to be generated by the counting device. The signal generated by the actuator after any of the rods passes through the qqi i nn / eznz / R / viAi actuator is processed in the electronic unit to increment the counter, which is preferably reset to zero after the zero rod passes. In this way, the electronic unit can advantageously associate the position values ​​generated by the position sensors with the corresponding rod. This also makes it possible to detect wear on the rollers of each rod and intervene on those rollers that require maintenance. The method according to the invention essentially comprises a calibration step, a measurement step, and a prediction and signaling step. Ideally, the calibration step is carried out immediately after the machine is installed or after a maintenance activity that affects the measuring unit. According to the invention, in a measuring unit comprising a plurality of sliding rods, said calibration step is carried out for each of said rods of said plurality of rods. This calibration step provides a calibration cycle or adjustment, which is intended to identify comparison values ​​for subsequent review of roller wear during normal machine use. For each rod or sliding piston, the calibration values ​​are determined at this stage: average measured distance and measurement dispersion (maximum value and minimum value). For each rod, the distance measurement is taken during machine operation and over a large number of cycles. Subsequently, a weighted moving average of the detected values ​​is calculated to filter out any abnormal fluctuations in the readings. The dispersion is calculated using the stored maximum and minimum values. In this way, for each rod, pairs of reference values ​​are obtained: one value representing the average detected distance and another representing the dispersion between the minimum and maximum detected values. The measurement step of the method according to the invention provides, preferably continuously, the position values ​​for each rod, whose values ​​will be compared with what has been found and stored in the calibration step. According to the invention, maximum deviation values, i.e., deviation thresholds, are provided for the values ​​measured during normal machine operation, with respect to the values ​​stored for each rod in the calibration step. These deviation thresholds make it possible to determine two typical parameters and corresponding roller wear indices. Specifically, the deviation from the average value is an indicator of wear, that is, of the diameter of the roller, while the deviation from the dispersion value is an indicator of ovality. QQI I ηη / Ρ7Π7 / Β / νΐΛΙ that is, the deviation from the circular shape or asymmetric wear of the roller. According to the invention, the method also provides a prediction and signaling step, in which, based on measurements acquired over time, a signal is generated indicating the need to replace the worn roller and whether that need is imminent, or when the roller will need to be supplied and replaced. This prediction can also be based on statistical information stored in a database and, therefore, take into account the operation of the same mechanical component, i.e., the roller, in different machines, or it can operate locally by means of a predictive algorithm. The invention is particularly advantageous also thanks to the selection of the preferred sensor attachment position, the type of sensor, and the use of the measurement algorithm described above. BRIEF DESCRIPTION OF THE DRAWINGS Some preferred embodiments of the invention are provided by way of non-limiting examples with reference to the accompanying drawings, in which: Figure 1A is a schematic front view of a measuring unit made according to a preferred embodiment of the invention; Figure IB is a perspective view of a detail of the measuring group in Figure 1A; Figure 2 is a front view of a rotating revolving unit of a capping machine incorporating the measuring unit according to the invention; Figure 3 is a view corresponding to Figure IB according to a particular embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION Referring to Attached Figures 1A and 1B, a measuring unit 11 is illustrated for measuring the wear of the surface of revolution or the contact surface of rotating members, such as rollers, needle bearings, cylinders, bushings, etc., according to the invention. In the illustrated version, Unit 11 essentially comprises: - a support structure (13); - a plurality of rods 15 having a first sliding motion, along a direction having a rectilinear component SI and parallel to the vertical axis of each rod 15 qqi i nn / cznz / B / viAi with respect to the support structure 13; - a cam guide 17 having a second relative movement with respect to the sliding rods 15, said second movement being capable of causing the movement of the rod 15 along said sliding direction SI; - a pair of rollers 19a, 19b rotatably fixed to each sliding rod 15 and in rolling contact with a track 21a, 21b defined in said cam guide 17, so that the second relative movement between the cam guide 17 and the sliding rod 15 causes the first movement of the rod 15 along said sliding direction SI. According to the invention, the measuring unit 11 comprises an indicator 23 or sensor for the position of at least one roller 19a of the roller pair 19a, 19b along the rectilinear direction SI. The indicator is capable of generating an electrical signal indicating the distance between the indicator 23 and the at least one roller 19a of the roller pair 19a, 19b. In the illustrated embodiment, the indicator 23 is capable of detecting the position of the upper roller 19a of the roller pair 19a, 19b, i.e., the roller closest to an upper end of the rod 15. In another embodiment of the invention, the indicator 23 is capable of detecting the position of both rollers 19a, 19b of the roller pair 19a, 19b or only the position of the lower roller 19b, i.e., the roller distal to the upper end of the rod 15. Furthermore, in the illustrated mode, the indicator 23 or sensor is anchored to the support structure 13. In other modes, it may take a different position. In this embodiment, the pair of rollers 19a, 19b is rotatably fixed to the rod 15, at an upper end of the rod, when the rod is mounted vertically relative to the support structure 13. More particularly, the pair of rollers 19a, 19b is rotatably fixed to the sliding rod 15 by means of an individual support fork 25, the indicator 23 is capable of generating an electrical signal indicating the distance between said indicator 23 and an upper end 25a of said fork 25 proximal to said indicator 23. The distance d measured by the position indicator 23 is measured parallel to said SI rectilinear direction of sliding of rod 15. Furthermore, indicator 23 is attached to the support structure 13 by means of a curved plate TI provided with an eyelet 27a in which indicator 23 is secured. This eyelet allows adjustment of the indicator's position so that the indicator is aligned along the SI direction passing through the rotation axes of both rollers 19a and 19b when the corresponding rod 15 is vertically aligned with the sensor. The measurement of the distance d between indicator 23 and the upper end 25a of the fork 25 takes place in this aligned position. The signal generated by indicator 23 is sent, via a cable 23a, to an electronic control unit (not shown) programmed to process the signal and implement the measurement method according to the QQI I ηη / Ρ7Π7 / Β / ΥΙΛΙ invention. In this embodiment of the invention, the indicator 23 comprises a position induction sensor based on eddy currents. In the illustrated embodiment, the rotation axes of rollers 19a, 19b are parallel to each other, and the other rollers 19a, 19b roll in contact with a corresponding bearing track 21a, 21b defined in said cam guide 17. Furthermore, the axis of rotation of each roller 19a, 19b of said roller pair intersects with said rectilinear SI sliding direction of rod 15. With reference to Figure 2, a revolving drum 31 of a capping machine 33 incorporating a measuring unit 11 according to the invention is illustrated. The capping machine 33 comprises a support structure 13 on which a carousel 45 of capping heads 37, each of which is designed to apply a cap to a corresponding bottle, is mounted around a vertical axis S2. The bottles are designed to be carried to a platform 39, this platform can also rotate around the same axis S2 synchronously with the carousel 35, so that as each bottle is transported by the rotating platform 39, which moves on a circular path around axis S2, it is followed by a corresponding capping head 37 after having received on its neck a cap to be applied, which comes from a cap container, not shown. During the rotation of carousel 35, each capping head 37 is lowered onto the bottle and performs a vertical movement along the SI direction to apply the cap to the bottle. In this mode, the relative movement between the carousel 35 and the cam guide 17 associated with the unit 11, carried out by the revolving 31, is a cyclic and periodic movement capable of causing a back-and-forth movement of each rod 15 along a corresponding SI direction, thanks to the cooperation between the roller pairs 19a, 19b and the tracks 21a, 21b of the cam guide 17. With reference now to figure 3, a revolving reel 31 of a capping machine 33 is illustrated, which incorporates a measuring unit 11 according to a particular embodiment of the invention. In this embodiment, the measuring unit 11 further comprises a counting device 41, preferably associated with an electronic control unit in which the incoming signals from the indicator 23 are processed by means of suitable software. The counting device 41 is capable of generating a signal indicating the presence of one of the sliding rods 15 that carry the rollers 19a, 19b. Normally, this rod 15 is referred to as the zero rod, so QQI I ηη / R7P7 / B / YILI The signal generated by the counter device 41 after the passage of said zero rod corresponds to the conclusion of an operation cycle in which all the remaining rods 15 have passed through the position sensor 23. Preferably, the measuring unit 11 according to this embodiment of the invention also comprises an activating sensor 43, preferably associated with said electronic unit and capable of generating an indicator signal of the passage of each rod 5 in said activating sensor 43. According to a particular embodiment of the invention, during the operation of the measuring unit 11, each rod 15 will pass through the counting device 41 but, preferably, only the zero rod equipped with means arranged to interact with the counting device 41 will cause a corresponding signal to be generated by said counting device 41. The signal generated by actuator 43 after any of the rods 15 pass through the actuator is processed in the electronic unit to increment the counter, which is preferably reset to zero after the zero rod passes through. In this way, the electronic unit can advantageously associate the position values ​​generated by indicator 23 with the corresponding rod 15. Advantageously, this makes it possible to detect wear on rollers 19a and 19b on each rod 15 and intervene only on those rollers that require maintenance. According to a particular embodiment of the invention, said means arranged for interacting with the counting device 42 comprise a cylindrical reference element 45 attached to the rod 15 that has been selected as the zero rod, preferably parallel to the rectilinear component of the sliding direction of the rod 15. In addition, the plate TI will be advantageously provided with a second eyelet 27b in which the counting device 41 is secured. Therefore, in the illustrated mode, the counter device 41 is attached to a different and larger rotation diameter than the diameters of the wear indicator 23 and the actuator 43, both of which are received in the eyelet 23a. During the operation, the rod 15 selected as the zero rod passes, in each rotation, through the counting device 41, so the software recognizes that a complete rotation has been carried out. After the fork passes through the actuator 43, located immediately upstream of the indicator 23, the software updates the counter device 41 by incrementing it from piston to piston until a total number of pistons is reached, and records the corresponding degree of wear by associating it with its piston. As described and illustrated, the invention is susceptible to various modifications and variations that fall within the same inventive principle.

Claims

1. A container treatment machine comprising a measuring unit (11) for measuring the wear of the surface of revolution of rotating members, said measuring unit comprising: - a support structure (13); - a rod (15) having a first sliding movement along a direction having a rectilinear component (SI) with respect to the support structure (13); - a cam guide (17) having a second relative movement with respect to the sliding rod (15); - at least one roller (19a, 19b) rotatably fixed to the sliding rod (15) and in rolling contact with a corresponding track (21a, 21b) of said cam guide (17), such that the second relative movement between the cam guide (17) and the sliding rod (15) causes the first movement of the rod (15) along said sliding direction (SI);wherein said measuring unit (11) comprises an indicator (23) of the position of said roller (19a, 19b) along said straight component (SI), said indicator being capable of generating an electrical signal indicating the distance (d) between said indicator (23) and said roller (19a, 19b), characterized in that said distance (d) is compared with at least one deviation threshold to determine the degree of wear of a surface of said at least one roller (19a, 19b) and in that said distance (d) is compared with at least one deviation threshold of values ​​measured during normal machine operation, with respect to the values ​​stored during the calibration step..; 2. The container treatment machine according to claim 1, further characterized in that said roller (19a, 19b) is rotatably fixed to the sliding rod (15) by means of a support fork (25), and wherein the indicator (23) is capable of generating an electrical signal indicating the distance between said indicator (23) and an end (25a) of said fork (25) proximal to said indicator (23).

3. The container treatment machine according to any of the claims, further characterized in that said rod (15) comprises a pair of rollers (19a, 19b) that can rotate about parallel axes, each roller being in rolling contact with a track (21a, 21b) of said cam guide.

4. The container treatment machine according to claim 1, further characterized in that the axis of rotation of each roller (19a, 19b) of said pair of rollers (19a, 19b) intersects with said straight component.

5. The container treatment machine according to claim 1, further characterized in that said distance (d) is measured in a direction parallel to said qqi i nn / eznz / R / YiAi rectilinear component.

6. The container treatment machine according to claim 1, further characterized in that said unit comprises a plurality of said rods (15).

7. The container treatment machine according to claim 1, further characterized in that said second movement is a cyclic periodic movement, capable of causing a forward and backward movement of said rod (15).

8. The container treatment machine according to claim 1, further characterized in that said indicator (23) is a non-contact touch sensor.

9. The container treatment machine according to claim 1, further characterized in that a counting device (41) is provided capable of generating an indicator signal of the presence of one of the sliding rods (15) holding the rollers (19a, 19b), such that the signal generated by the counting device (41), after the passage of said rod corresponds to the conclusion of an operating cycle during which all the remaining rods (15) have passed through the indicator (23).

10. The container treatment machine according to claim 9, further characterized in that an activator sensor (43) is provided capable of generating an indicator signal of the passage of each rod (15) in the activator sensor (43).

11. A measuring method for measuring the wear of the surface of revolution of rotating members in a container treatment machine comprising a measuring unit of the type comprising: - a support structure (13); - a rod (15) having a first sliding motion along a direction having a rectilinear component (SI) with respect to the support structure (13); - a cam guide (17) having a second relative motion with respect to the sliding rod (15); - at least one roller (19a, 19b) rotatably fixed to the sliding rod (15) and in rolling contact with a corresponding track (21a, 21b) of said cam guide (17), such that the second relative motion between the cam guide (17) and the sliding rod (15) causes the first motion of the rod (15) along said sliding direction (SI), wherein it comprises the step of providing an indicator (23) of the position of said roller (19a,19b) along said rectilinear component (SI), said indicator is capable of generating an electrical signal indicating the distance (d) between said indicator (23) and said roller (19a, 19b), further characterized in that said distance (d) is compared with at least one deviation threshold to determine the degree of wear of a surface of said at least one roller (19a, 19b) and in that said distance (d) is compared with at least one deviation threshold of values ​​measured during normal machine operation, with respect to the values ​​stored during a calibration step.

12. The method according to claim 11, further characterized in that the calibration step comprises a number of operating cycles of the measuring unit and measuring the moving average of said distance and measurement dispersion.

13. The method according to claim 11, further characterized in that said unit comprises a plurality of said rods (15), and wherein said calibration step 5 of said measuring unit comprises a calibration step of each of said rods of said plurality of rods (15).

14. The method according to claim 11, further characterized in that it comprises a step for determining the presence of one of the sliding rods (15) that holds the rollers (19a, 19b), whereby the signal generated by the counting device (41), after the passage of said rod corresponds to the conclusion of an operating cycle during which all the remaining rods (15) have passed through the indicator (23).

15. The method according to claim 11, further characterized in that it additionally comprises a step of recognizing each rod (15) by means of an activating sensor (43) capable of generating an indicator signal of the passage of each rod (15) in said activating sensor 15 (43).

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