Apparatus and method for measuring a ribbed wire

Abstract

Apparatus (10) for measuring a ribbed wire (100) comprising a non-contact measurement device (13) having at least one transmitter (14) and at least one receiver ( 15) which are disposed facing each other, between which there is defined a free measurement section (16) which said ribbed wire (100) can pass through in order to measure a diameter (D) thereof.

Description

[0001] “APPARATUS AND METHOD FOR MEASURING A RIBBED WIRE”

[0002] FIELD OF THE INVENTION

[0003] The present invention concerns an apparatus for measuring a metal wire, preferably ribbed, which can usually be used in the construction sector, for example to make reinforcements for reinforced concrete.

[0004] BACKGROUND OF THE INVENTION

[0005] The need to use ribbed steel wires, rods or bars is well known in, but not limited to, the construction industry. Their production requires careful analysis in terms of both mechanical and also dimensional properties, typically established by specific industry standards.

[0006] One of the most important parameters is the equivalent diameter, which, due to the presence of the ribs on the wire’s surface, is difficult to identify and has to remain within a pre-established percentage tolerance range.

[0007] Of course, in the mass production of large quantities of ribbed wire, producing a wire with an equivalent diameter as close as possible to the lower limit imposed by standards allows the manufacturer to save material, or produce more meters of wire, and therefore increase profits.

[0008] The state of the art of current measuring apparatuses refers to smooth rods, using linear cameras or measuring lasers. When there are ribs on the surface these systems fail, or in any case become very imprecise, because their operation is, for example, attributable to that of a mechanical gauge.

[0009] The problem of measurement error is amplified in the event that the measurement takes place downstream of a rolling cassette from which the wire exits at a certain speed and with a natural tendency to rotate around its own axis. In this case, it is even more difficult to be able to define a stable reference measurement for the diameter because, depending on the angle at which the measurement is carried out, even very different values can be obtained.

[0010] There is therefore the need to perfect an apparatus for measuring a ribbed wire that can overcome at least one of the disadvantages of the state of the art.

[0011] To do this, it is necessary to resolve the technical problem of measuring the equivalent diameter of a ribbed wire with precision, within a pre-established tolerance range. In particular, a purpose of the present invention is to provide an apparatus and perfect a method for measuring the equivalent diameter of a ribbed wire, even advancing linearly at a speed comprised between about 0.1 m / s and about 20 m / s, which is stable, precise and has relatively low costs.

[0012] The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

[0013] SUMMARY OF THE INVENTION

[0014] The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

[0015] In accordance with the above purposes and to resolve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, an apparatus for measuring a metal wire, preferably ribbed, according to the present invention comprises a non-contact measurement device having at least one transmitter and at least one receiver which are disposed facing each other, between which there is defined a free measurement section which the ribbed wire can pass through.

[0016] In accordance with one aspect of the present invention, the measuring apparatus comprises an angular positioning member with which the measurement device is associated, which can be angularly oriented around a central axis to acquire a plurality of diameter measurements of the ribbed wire. The apparatus also comprises a processing and control unit configured both to command the rotation of the angular positioning member and also to receive and process the diameter measurements, in order to obtain a plurality of equivalent diameter measurements to be compared with a corresponding plurality of equivalent diameter measurements of a “sample” ribbed wire so as to calculate a deviation value thereof.

[0017] Doing so achieves a measuring apparatus capable of accurately measuring the equivalent diameter of a ribbed wire with obvious advantages linked to savings of material, or to a greater production of wire, and therefore to an increase in profit for the manufacturing company.

[0018] In accordance with another aspect of the present invention, the measurement device is advantageously a laser or optical micrometer.

[0019] In accordance with another aspect of the present invention, the laser or optical micrometer can be single-axis.

[0020] According to a variant of the invention, the laser or optical micrometer can be multiple-axis.

[0021] In accordance with another aspect of the present invention, the measuring apparatus advantageously comprises a single measurement device.

[0022] In accordance with another aspect of the present invention, the measuring apparatus can comprise confinement means, for example confinement rolls, disposed upstream and downstream of the measurement device between which the ribbed wire passes.

[0023] The present invention also concerns a corresponding method for measuring a metal wire, preferably ribbed. The method comprises a supply step in which a ribbed wire is disposed through a measurement section defined by at least one transmitter and at least one receiver, which are disposed facing each other, of a non-contact measurement device.

[0024] In accordance with one aspect of the present invention, the method comprises an orientation step in which the measurement device is oriented angularly by means of an angular positioning member around a central axis, in order to acquire a plurality of diameter measurements of the ribbed wire.

[0025] The method also comprises a receiving and processing step in which a processing and control unit receives the diameter measurements to obtain a plurality of equivalent diameter measurements to be compared with a corresponding plurality of equivalent diameter measurements of a “sample” ribbed wire, in order to calculate a deviation value thereof, for example in percentage terms.

[0026] In accordance with another aspect of the present invention, the measurement device is oriented around the central axis at certain pre-established angular and temporal intervals.

[0027] In accordance with another aspect of the present invention, the receiving and processing step comprises:

[0028] - receiving for each acquisition angle a plurality of diameter measurements of the ribbed wire, - calculating a metric of the diameter measurements acquired for each acquisition angle obtaining N-values of equivalent diameter corresponding to the N- acquisition angles,

[0029] - comparing the current curve of the ribbed wire being worked with a nominal curve of a “sample” ribbed wire previously acquired in a sample acquisition step,

[0030] - evaluating the conformity of the equivalent diameter values obtained with respect to pre-established values.

[0031] In accordance with another aspect of the present invention, before the comparison step, the method can provide to apply an algorithm comprising instructions which allow to minimize the distance between the current curve and the nominal curve.

[0032] In accordance with another aspect of the present invention, the ribbed wire can advance linearly, parallel to the central axis, at a speed comprised between 0.1 m / s and 20 m / s. In this case, given the speed of advance of the ribbed wire, for example detected by means of specific sensors, it is possible to obtain a mass flow value, and given the density of the material, it is also possible to obtain a mass value.

[0033] In accordance with another aspect of the present invention, the metric can be chosen from a minimum, average or maximum value, an average of only the maximum peaks, a (maximum value - minus minimum value) / 2 of the diameter measurements.

[0034] DESCRIPTION OF THE DRAWINGS

[0035] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

[0036] - fig. 1 is a schematic three-dimensional view of an apparatus for measuring a ribbed wire according to the present invention;

[0037] - fig. 2 is a schematic lateral view of the apparatus of fig. 1 ;

[0038] - fig. 3 shows a sampling sequence of the diameter of the ribbed wire through the rotation of the measurement device;

[0039] - fig. 4 shows an example of a current curve of the equivalent diameter of a ribbed wire;

[0040] - figs. 5 and 6 show the application of the “best-matching” algorithm to a current curve and a nominal curve of a corresponding “sample” ribbed wire; and

[0041] - fig. 7 shows the comparison between two current curves and a corresponding nominal curve.

[0042] We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

[0043] To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

[0044] DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

[0045] Figs. 1 and 2 show an apparatus 10 for measuring a ribbed metal wire 100 according to the present invention.

[0046] The term ribbed wire 100 is understood as a type of wire, typically made of steel, which has a lateral surface with longitudinal ribs, usually with a spiral, herringbone or stepped shape.

[0047] The ribbed wire 100 is produced in different sizes, with diameters ranging from about 3.4 mm to about 16 mm.

[0048] We must clarify that the measuring apparatus 10 finds advantageous application with ribbed wire, but can also be used for smooth wire.

[0049] The measuring apparatus 10 comprises a fixed structure 11 on which an angular positioning member 12 is mounted, and at least one measurement device 13 attached to the angular positioning member 12, by means of which it can be angularly oriented around a central axis X, as visible for example in fig. 3.

[0050] The ribbed wire 100 can be disposed, and possibly made to advance, along the central axis X, through the measurement device 13.

[0051] The measurement device 13 is a single-axis or multiple-axis laser or optical micrometer.

[0052] The measurement device 13 comprises at least one transmitter 14 and at least one receiver 15, which are disposed facing each other, between which there is defined a free measurement section 16 which the ribbed wire 100 passes through, during use. These devices are essentially “barrier” sensors that measure any object that blocks light passing from the transmitter 14 to the receiver 15.

[0053] The transmitter 14 and the receiver 15 are mounted fixed on a support body 17 of the measurement device 13.

[0054] The central axis X is essentially orthogonal to the measurement section 16.

[0055] The measurement device 13 can have a sampling frequency comprised between about 1 Hz and about 16 kHz.

[0056] The rotation member 12 is also constructed centrally hollow to allow the passage of the ribbed wire 100, for example it can be provided with a central aperture 23, fig. 1.

[0057] The rotation member 12 is connected to a motor 22 which allows for a controlled rotation thereof, fig. 2.

[0058] The measurement device 13 is oriented around the central axis X at angular Act and temporal AT intervals to acquire a plurality of diameter measurements D of the ribbed wire 100.

[0059] The angular intervals Aa can be comprised between about 1 ° and about 90°. In one example embodiment, the angular intervals Aa are 10°.

[0060] The temporal intervals AT can be comprised between about 0.2 s and about 2 s. In one example embodiment, the temporal intervals AT are approximately 0.25 s.

[0061] The measuring apparatus 10 comprises a processing and control unit 18 configured both to command the rotation of the angular positioning member 12, according to the angular Aa and temporal AT intervals established, and also to receive and process the diameter measurements D of the ribbed wire 100 acquired by the measurement device 13, so as to obtain a plurality of equivalent diameter DE measurements to be compared with a corresponding plurality of equivalent diameter Do measurements of a “sample” ribbed wire in order to evaluate its percentage deviation.

[0062] The processing and control unit 18 comprises a storage module 18a and a processing module 18b.

[0063] According to the present invention, the measuring apparatus 10 is equipped with a single measurement device 13 capable of being rotated as described above.

[0064] The processing and control unit 18 is programmed to execute a computer program, stored in the storage module 18a, to implement the following steps of the method for measuring a ribbed wire, which corresponds to the operation of the measuring apparatus 10 described heretofore.

[0065] The measuring method comprising a supply step in which a ribbed wire 100 is disposed through the measurement section 16 defined by the at least one transmitter 14 and the at least one receiver 15, which are disposed facing each other, of the measurement device 13.

[0066] According to the present invention, the method comprises an orientation step in which the measurement device 13 is oriented angularly by means of an angular positioning member 12 around the central axis X to acquire a plurality of diameter measurements D of the ribbed wire 100, with angular interval Acc and temporal interval AT.

[0067] The method also comprises a receiving and processing step in which the processing and control unit 18 receives the diameter measurements D to obtain an equivalent diameter DE measurement to be compared with a plurality of equivalent diameter Do measurements of a “sample” ribbed wire in order to calculate a deviation value thereof.

[0068] The receiving and processing step in turn comprises the following steps.

[0069] Receiving S200 for each acquisition angle al, ..., aN a plurality of diameter measurements D 1,1, ..., DI,M, ..., DN,I, ..., DN,M where M is the acquisition number in correspondence with each acquisition angle al, ..., aN and N is the number of acquisition angles. The measurements acquired for each angle al, .. ., aN define a pseudo-sinusoidal curve having the acquisition angle expressed in degrees as an abscissa and the diameter expressed in mm as an ordinate.

[0070] In other words, for each acquisition angle al, ..., aN corresponding to the angle of rotation of the measurement device 13, “M” samples of the measurement of the diameter of the ribbed wire D (a, M) are acquired while it is advancing parallel to the central axis X.

[0071] For a given acquisition angle ai, by drawing the acquired samples on a graph where the number of the sample is in the abscissa and the corresponding diameter measurement is in the ordinate, a pseudo-sinusoidal curve is obtained whose periodicity depends on the speed of advance of the ribbed wire 100 (please see the curves shown in the abscissa in the graph of fig. 4).

[0072] According to one possible example embodiment, and considering a ribbed wire 100 advancing at about 20 m / s, if the measurement device 13 operates at a sampling frequency of 16 KHz, a measurement is acquired every 1.25 mm, and to acquire 4000 measurements at each angle a a temporal interval AT of 0.25 s will be required. The angular interval Aa of acquisition can be set at 10°. The positioning speed of the measurement device 13 is set at about 0.5s, therefore the complete cycle for the acquisition of 180° will have a cycle time of about 13.5s. Therefore, 18 pseudo-sinusoidal curves are obtained in about 15s.

[0073] Calculating S300 a metric of the diameter measurements Di,i, ..., DI,M, ..., DN.I, ..., DN.M acquired for each angle al, ..., aN, obtaining N-values of equivalent diameter DE corresponding to the N-acquisition angles. The N-values of equivalent diameter DE define a current curve having the acquisition angle in abscissa and the equivalent diameters DE in ordinate, fig. 4.

[0074] This metric, understood as the “distance” between two elements, in this case between the diameter values acquired at a certain acquisition angle, can be chosen from a minimum, average or maximum value, an average of only the maximum peaks, a (maximum value - minus minimum value) / 2, or other metrics.

[0075] For example, considering the arithmetic mean value, the result for the angle al would be: DE 1=D1,m.

[0076] Comparing S400 the current curve of the ribbed wire 100 being worked with a nominal curve of a “sample” ribbed wire previously acquired in a sample acquisition step SI 00, figs. 5-7. This step SI 00 typically occurs only once, or every time a new “sample” ribbed wire is inserted in the system.

[0077] The nominal curves of the “sample” ribbed wires are stored in the storage module 18a of the processing and control unit 18.

[0078] If the measurement of the ribbed wire 100 takes place while the latter is advancing, but not only in this case, before the comparison step S400 it may be necessary to apply S500 a “best-matching” algorithm, figs. 5 and 6.

[0079] In fact, the advancing ribbed wire 100 tends to rotate around its own axis, therefore its current curve would be out of phase with the nominal curve of the corresponding “sample” ribbed wire.

[0080] For example, the algorithm can contain instructions that when executed by the processing and control unit 18 allow to minimize the distance between the two curves, understood as IlTt - tll, where yi are the points of the current curve and Xi are the points of the “sample” ribbed wire nominal curve and || (x)|| is the Euclidean norm.

[0081] Finally, evaluating S600 the conformity of the equivalent diameter values obtained with respect to pre-established values, for example defined by industry regulations. The evaluation takes place automatically through the processing and control unit 18. Fig. 7 shows how the upper curve indicates an equivalent diameter DE increasing with respect to the reference one (central curve), while on the contrary the lower curve indicates an equivalent diameter DE decreasing with respect to the reference one.

[0082] The measuring apparatus 10 can comprise a user interface 19 connected, physically or wirelessly, to the processing and control unit 18 in order to display the results to an operator, figs. 1 and 2.

[0083] The user interface 19 can be installed on board the machine or it can be remotely operated.

[0084] The user interface 19 can be physical, including screens, possibly touchscreens, keys, dials, remote controls, or virtual, for example a smartphone and tablet application or a web interface.

[0085] The measuring apparatus 10 can comprise confinement rolls 20, 21 disposed upstream and downstream of the measurement device 13 in such a way as to reduce any vibrations or deformations on the segment of ribbed wire 100 being measured.

[0086] It is clear that modifications and / or additions of parts may be made to the apparatus 10 and to the method for measuring a ribbed wire 100 as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims.

[0087] It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of apparatus and method for measuring a ribbed wire, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

[0088] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

CLAIMS1. Apparatus (10) for measuring a ribbed wire (100) comprising a non-contact measurement device (13) having at least one transmitter (14) and at least one receiver (15) which are disposed facing each other, between which there is defined a free measurement section (16) which said ribbed wire (100) can pass through, characterized in that it comprises an angular positioning member (12) with which said measurement device (13) is associated which can be angularly oriented around a central axis (X) to acquire a plurality of diameter measurements (D) of said ribbed wire (100), and in that it comprises a processing and control unit (18) configured both to command the rotation of said angular positioning member (12) and also to receive and process the diameter measurements (D) in order to obtain a plurality of equivalent diameter (DE) measurements to be compared with a corresponding plurality of equivalent diameter (Do) measurements of a “sample” ribbed wire in order to calculate a deviation value thereof.

2. Measuring apparatus (10) as in claim 1, characterized in that said measurement device (13) is a single-axis or multiple-axis laser or optical micrometer.

3. Measuring apparatus (10) as in claim 1 or 2, characterized in that it comprises a single measurement device (13).

4. Measuring apparatus (10) as in claim 1 or 2, characterized in that it comprises confinement rolls (20, 21) disposed upstream and downstream of said measurement device (13) between which said ribbed wire (100) passes.

5. Method for measuring (10) a ribbed wire (100) comprising a supply step in which a ribbed wire (100) is disposed through a measurement section (16) defined by at least one transmitter (14) and at least one receiver (15), which are disposed facing each other, of a non-contact measurement device (13), characterized in that it comprises an orientation step in which said measurement device (13) is oriented angularly by means of an angular positioning member (12) around a central axis (X) to acquire a plurality of diameter measurements (D) of said ribbed wire (100), and a receiving and processing step in which a processing and control unit (18) receives said diameter measurements (D) to obtain a plurality of equivalent diameter (DE) measurements to be compared with a corresponding plurality of equivalent diameter (Do) measurements of a “sample” ribbed wire inorder to calculate a deviation value thereof.

6. Measuring method (10) as in claim 5, characterized in that said measurement device (13) is oriented around said central axis (X) at certain pre-established angular (Aa) and temporal (AT) intervals.

7. Measuring method (10) as in claim 5 or 6, characterized in that said receiving and processing step comprises:- receiving (S200) for each acquisition angle (ai, ..., OCN) a plurality of diameter measurements (D i , ... , D I,M, ■ • ■ , DN, I , . . . , DN,M) of the ribbed wire ( 100),- calculating (S300) a metric of the diameter measurements (Di,i, ..., DI,M, ■ ■ ■, DN,I, DN,M) acquired for each acquisition angle ((ai, ...,obtaining N- values of equivalent diameter (DE) corresponding to the N-acquisition angles,- comparing (S400) the current curve of the ribbed wire (100) being worked with a nominal curve of a “sample” ribbed wire previously acquired in a sample acquisition step (SI 00),- evaluating (S600) the conformity of the equivalent diameter values obtained with respect to pre-established values.

8. Measuring method (10) as in claim 7, characterized in that before comparing (S400) it provides to apply (S500) an algorithm comprising instructions which allow to minimize the distance between said current curve and said nominal curve.

9. Measuring method (10) as in claim 7 or 8, characterized in that said ribbed wire (100) advances linearly parallel to said central axis (X) at a speed comprised between 0.1 m / s and 20 m / s.

10. Measuring method (10) as in any claim from 7 to 9, characterized in that said metric can be chosen from a minimum, average or maximum value, an average of only the maximum peaks, a (maximum value - minus minimum value) / 2 of said diameter measurements (Di,i, ..., DI,M, DN,I, ..., DN,M) at a certain acquisition angle (ai, ..., OCN).

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