TRANSMISSION ELEMENT SUCH AS A CHAIN OR A BELT

The present invention relates to a method and system for verifying the modification of a transmission element such as a chain or belt.

It should be noted that the term "modification" in this patent refers to any problem that may arise in a transmission element such as a chain or belt as a result of any kind of stress. In particular, modification refers to wear, an elongation, a dimensional variation in general, a misalignment, a clearance and whatever else is created in this element as a result of its use and functioning.

In the technical field of motion transmission by means of chains, belts and motion transmission elements of the kind arranged between parallel rotation shafts, an evaluation of the wear that is created is of certain importance.

In some cases, in fact, it is vital to be able to intervene before the chain or belt stretches or lengthens to the extent of causing a failure in the entire system where it is positioned.

For this purpose, various systems and devices have been developed which, by verifying the modification of the transmission element, try to identify wear and any other variation in the element in order to schedule the predictive maintenance of the system or component. Some of these systems resort to at least two markers positioned on the chain or belt or rather between its links which are detected by at least two sensors fixed to their passage. The system refers to the situation at the start of functioning, with a new chain or belt and without any elongation .

Should there be any elongation or any sign of wear, the dialogue between markers and sensors will vary or there are dialogue delays between sensors and markers and an alarm is generated for users.

An example of known systems of this type is provided in EP 2 908 097 A1 which describes a method and system for measuring the lengthening of a chain by means of inductive reluctance sensors .

This system does not seem to be without problems due to its initial arrangement and to the positioning of the two sensors along the path of the chain. Furthermore, special markers must be arranged on the chain or belt in specific positions, suitable and above all correct, and adapted to the initial arrangement.

Last but not least, problems arise for the connection of the sensors to the detection and control system for the arrangement of the transmission and power cables.

As in this example, further known arrangements also have the above-mentioned problems which do not facilitate the detection and occurrence of elongations, similar distortions of other modifications from the initial state of use.

The objective of the present invention is to be able to identify a method or system that is capable of monitoring the modification or in general the wear of the chain, belt or similar transmission element with a single sensor, possibly without having to position any specific element on the chain, belt or similar transmission element to be kept under control.

An objective related to the previous objective is to identify a method or system which is capable of verifying the modification, wear or elongation of the transmission element of the type mentioned above in order to be able to identify them rapidly and safely, so as to plan the predictive maintenance of the component .

The above-mentioned objectives are achieved by a method or system produced according to the independent claims and following sub-claims.

The structural and functional characteristics of the present invention and its advantages with respect to the known art will become clearer and even more evident from the following description, referring to the attached schematic drawings, which show an embodiment example of the invention. In the drawings :

figure 1 represents a simplified system which provides a laser distance transducer which observes the position of one of the elements already present on the chain, or in any case on a trolley, belt or the like, or of any element that can be observed by the transducer;

- figure 2 shows an example of a signal acquired by a system and a method according to the invention, for example in the verification of a transmission chain, wherein the coordinates of the graph that represents it are the distance between the transducer and the element present on the chain and the time respectively;

- figure 3 shows an algorithm for analyzing data acquired with the system and method of the invention;

- figure 4 shows an example of an industrial chain which can be used for the development of the method and system according to the present invention.

With reference to the figures, by way of non-limiting example, these show an embodiment of a system for verifying the modification of a transmission element such as a chain or a belt .

As already indicated previously, the term "modification" refers to any problem that arises in a transmission element such as a chain or belt as a result of any type of stress. In particular, modification refers to wear, an elongation, a dimensional variation in general, a misalignment, a clearance and whatever else is created in this element as a result of its use and functioning. In an example of the system of the invention, figure 1 represents a simplified system of this kind which provides a non-contact sensor 11, such as for example an optical distance transducer, preferably a laser distance transducer, designed for observing the position of at least one detectable element 12 already present on any element or transmission element 13 such as a chain or trolley, a belt or the like, such as a motion-control transmission element, which can be observed by the above-mentioned optical distance sensor or transducer 11.

This system allows the modification of a transmission element such as a chain or belt according to the invention to be verified as a result of its functioning or any further stress .

This system and method, for example, are in fact capable of automatically monitoring the wear of the chain 13 or control element during its functioning in a control assembly that uses it .

Figure 2 shows an example of the signal acquired: the distance between the transducer and a single detectable or "target" element 12 on the chain will decrease until the target is wound on an end pinion 17, arranged at one end of the path of the chain 13, when the chain 13 rotates in the direction of the arrow 18.

In this phase, the motion can be approximated as a uniform straight motion and allows the speed of the chain to be estimated (section A on the graph in figure 2) . In the final section, due to the rotation of the detectable or "target" element 12 on the pinion 17, a greater speed will be measured (section B) until another detectable or "target" element 12 is observed (section A) .

The speed of the chain 13 is estimated only on sections A of the graph, with the algorithm summarized and schematized in figure 3.

After the start-up, the first analysis step consists in dividing the signal to identify useful sections of motion (A in figure 2) . This step allows the data (time - distance pairs) to be defined, for calculating the average speed of the transmission element 13.

The average speed is calculated in each of the sections A by regression on the data itself and allows the identification of linear equations of the type

s = s O + v * t

wherein :

- s O is the distance between the non-contact optical transducer 11 or measuring element and the chain 13 at the first useful moment of observation,

- v is the speed of the chain, and

- t is the time.

These equations are calculated for each useful section (Tl, T2 , T3 , Tn) . The next step consists in calculating the distance between detectable or "target" elements 12 of the subsequent sections (for example, Tl, T2), (if present) or between two successive passages of the same and only detectable element.

The calculation is effected by calculating the average value of the distance between the two interpolating straight lines calculated in the two sections.

The method therefore briefly comprises a series of successive steps as follows.

It should be noted that the chain 13 or control element provides, as already mentioned, at least one detectable element 12, for example in the form of a flap as shown in the example of a chain 13 of figure 4. Said detectable element 12 can be made of any material.

The non-contact sensor or optical distance transducer 11, preferably a laser distance sensor, is arranged to act through its light beam 14 in a direction essentially parallel to the movement direction (arrow 18) of the transmission element or chain 13 to intercept the above-mentioned at least one detectable element 12, made of any material, integral with the transmission element or chain 13.

A motor M for moving the chain 13 and the transducer 11 are connected via electrical connections 15 or through a wireless transmission system (not shown) to a data analysis system 16, such as a computer or the like. The data analysis system 16, for example, can record the data measured and allows the speed of the chain 13 to be calculated by interpolating the movement measured over time.

The analysis system 16 acquires the signal detected by the laser distance transducer 11 and processes it on the basis of a preselected parameter, such as for example a kinematic quantity such as position, speed or acceleration of the chain 13. A measurement of a kinematic quantity is therefore effected without contact.

This signal is related and processed for example, as already mentioned, in the graph shown in figure 2.

The algorithm schematized in figure 3 in brief shows the data analysis steps, which includes the division of the signal for identifying the useful sections of motion (sections A) .

In particular, it can be noted that after the start-up in

50, the signal is acquired in 51 and the signal is divided into segments or parts (in 52), for example corresponding to parts A of Figure 2.

The approximation or interpolation of each segment to a straight line is then effected (in 53) and the calculation of the distance between the interpolated lines or straight lines to compare it with the distance between the at least one detectable element 12 integral with the transmission element or chain 13 ( in 54 ) .

This is followed (in 55) by a step for calculating the distance between two passages of the at least one detectable element 12 integral with the transmission element or chain 13, or between several successive detectable elements 12 integral with the transmission element or chain 13, if present.

At this point a data transmission step is effected and writing of the results (in 56) with the end of the surveys.

This is followed by a possible step for the identification and reporting of anomalies in 57 which can be followed by various actions such as shutdown, alarm or other.

The data analysis system 16 therefore acquires the signal detected by the sensor or transducer 11 and processes it according to a preselected parameter (previously indicated) referring to the transmission element 13 during its functioning and reports it in comparison with a diagram or basic graph, reporting differences or anomalies.

The differences detected compared to a basic graph plotted and stored in the start-up phase with a new chain free of anomalies, indicate elongations or other drawbacks in the chain or in the motion-control transmission element that can be observed by the above-mentioned transducer 11.

It is evident that a method and a system have thus been developed that allow the detection and measurement of the elongation and/or modification in general of a chain 13, for example for transporting material in the industrial sector.

Figure 4 shows how the chains 13 often have elements 12 perpendicular and protruding with respect to the transmission direction of the movement. These protruding elements or flaps can act as a detectable or "target" element for measuring the displacement of the transducer 11 without contact (figure 1) and generating a signal similar to that of figure 2.

The regression on the data in figure 2 leads to the identification of the speed of the chain and the elongation or other abnormal modification of the chain itself 13.

A device for evaluating the modification state (for example wear or elongation) of the chain has therefore been indicated by means of a single non-contact sensor aligned with the main movement direction of the chain.

Through the present invention, it is therefore possible to monitor the wear of the chain, belt or similar transmission element with a single non-contact sensor that measures a kinematic quantity (position, speed or acceleration) without contact .

The verification of the modification of the transmission element allows its wear or any other variation in measurement to be identified, therefore allowing the predictive maintenance of the component to be scheduled.

It is particularly important to note that through a method and a system according to the present invention, a continuous reading is effected, of at least one detectable element 12, already present in the above-mentioned transmission element 13, which differs from the known systems.

The non-contact optical sensor 11, in fact, constantly focuses, during its motion, on the at least one detectable element 12 positioned on the transmission element 13, continuously monitoring its position and generating absolutely in continuous the situation of said transmission element 13.

Preferably, in order to safeguard spaces and dimensions, this non-contact optical sensor 11 is positioned in a direction substantially parallel to the movement direction of the transmission element 13.

The objective mentioned in the preamble of the description has thus been achieved.

The protection scope of the present invention is defined by the enclosed claims.