Machine and method for hot stretching a ribbed metal wire

Abstract

Stretching machine (10) for stretching a ribbed metal wire (100), comprising at least one stretching plate (12) on which there are mounted two rows of first and second idle stretching rollers (13, 14) symmetrically opposite a central axis (X) along which said ribbed metal wire (100) can advance, and a drawing device (19) configured to draw said metal wire (100) through said first and second stretching rollers (13, 14).

Description

[0001] “MACHINE AND METHOD FOR HOT STRETCHING A RIBBED METAL WIRE”

[0002] * * * * *

[0003] FIELD OF THE INVENTION

[0004] The present invention concerns a machine for stretching a ribbed metal wire, which is applied downstream of a corresponding hot rolling process in order to give certain mechanical characteristics to the finished product.

[0005] BACKGROUND OF THE INVENTION

[0006] The need to use ribbed steel wires, rods or bars is well known in the construction industry, but not limited thereto. Their production requires careful analysis in terms of both mechanical and also dimensional properties, typically established by specific industry standards.

[0007] The ribbed wire can be produced through a cold or hot rolling process. In the latter case, it is necessary to cold stretch the product so as to give it certain mechanical characteristics.

[0008] Stretching machines comprise at least one stretching plate or panel on which two rows of idle stretching rollers are mounted, defining between them a passage channel for a ribbed wire. The stretching rollers of one row can be moved close to / away from the stretching rollers of the other row to exert a certain pressure and flexion on the advancing ribbed wire, causing an elongation thereof and a corresponding reduction in section / diameter.

[0009] Controlling the elongation and diameter of the ribbed metal wire is a fundamental part of the stretching process. Precise control of these quantities is important to ensure that the ribbed metal wire meets the requirements of specific construction applications. In particular, both the elongation and also the diameter of the ribbed wire have to remain within a certain range imposed by industry regulations.

[0010] Currently, only elongation is measured, by taking a previously marked piece of ribbed wire after it has passed through the stretching rollers. Therefore, there is no continuous control of the elongation and not even a verification of the diameter of the ribbed wire as it advances. This greatly limits the control of the stretching process.

[0011] There is therefore the need to perfect a machine for stretching a ribbed metal wire that can overcome at least one of the disadvantages of the state of the art.

[0012] One purpose of the present invention is to provide a stretching machine in which the control of the elongation and of the diameter of the ribbed metal wire is optimized and can be controlled continuously or in any case “on the fly”.

[0013] 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.

[0014] SUMMARY OF THE INVENTION

[0015] 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.

[0016] In accordance with the above purpose 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, a stretching machine according to the present invention for stretching a ribbed metal wire comprises:

[0017] - two rows, opposite a central axis, of first and second idle stretching rollers associated with actuators configured to vary their distance from the central axis, and downstream a drawing device suitable to draw the metal wire;

[0018] - at least one measuring device disposed downstream of the stretching rollers configured to detect at least one physical quantity of the metal wire, and speed sensors disposed upstream and downstream of the stretching rollers configured to measure a speed of the metal wire;

[0019] - a processing and control unit configured to run a program which, on the basis of values correlated with a first signal from the measuring device, with a second signal from the sensors, with the density of the material constituting the metal wire, allows to calculate a current mass flow and to keep it within certain pre- established limits, possibly generating command signals for the drawing device and the actuators.

[0020] In accordance with another aspect of the present invention, the processing and control unit comprises a storage module in which the density and the mass flow limits are stored.

[0021] In accordance with another aspect of the present invention, the measuring device is a single-axis or multiple-axis laser or optical micrometer. In accordance with another aspect of the present invention, the stretching machine comprises another measuring device disposed upstream of the stretching rollers.

[0022] The present invention also concerns a method for stretching a ribbed metal wire which comprises:

[0023] - feeding a ribbed metal wire along a central axis through two rows of first and second stretching rollers;

[0024] - measuring, by means of a measuring device, a physical quantity of the ribbed wire at exit and sending a first signal containing the physical quantity to a processing and control unit and measuring, by means of speed sensors, the speeds of the metal wire at machine entry and exit;

[0025] - running a computer program on the basis of a compensation algorithm which allows, at least on the basis of values correlated with the first signal, with the second signal, with the density of the material constituting the metal wire, to calculate a current mass flow and to keep the current mass flow within certain pre-established limits, possibly generating command signals for the stretching rollers and for the drawing device;

[0026] -- moving the first and / or second stretching rollers to vary the distance with respect to the central axis by means of the actuators on the basis of the command signals.

[0027] In accordance with another aspect of the present invention, the physical quantity is the diameter of the ribbed metal wire, possibly processed to obtain an equivalent diameter value.

[0028] The present invention also concerns a computer-readable data carrier on which the computer program run in the method as disclosed above is stored.

[0029] DESCRIPTION OF THE DRAWINGS

[0030] 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:

[0031] - fig. 1 is a lateral schematic view of a machine for stretching a ribbed metal wire according to the present invention.

[0032] 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.

[0033] 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.

[0034] DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

[0035] With reference to fig. 1, this schematically shows a stretching machine 10 for stretching a ribbed metal wire 100.

[0036] The term ribbed metal 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.

[0037] Ribbed metal wire 100 is produced in different sizes, with diameters ranging from about 6 mm to about 26 mm.

[0038] The stretching machine 10 comprises a support structure 11 with which at least one stretching plate 12 is associated, on which two rows of first and second idle stretching rollers 13, 14 are mounted. The example of fig. 1 shows three first stretching rollers 13 and four second stretching rollers 14.

[0039] The stretching plate 12 can be disposed with a vertical orientation or inclined with respect to a horizontal plane. In some solutions, two or more stretching plates 12 can be disposed alternating with vertical and horizontal orientation.

[0040] The stretching machine 10 comprises a drawing device 19 configured to draw the metal wire 100 through the first and second stretching rollers 13, 14. The drawing device 19 is motorized and can comprise drawing rollers, wheels, or other.

[0041] The first and second stretching rollers 13, 14 are disposed symmetrically opposite a central axis X along which the ribbed metal wire 100 can advance.

[0042] The stretching rollers 13, 14 are made of hard and wear-resistant materials, such as hardened steel or tungsten carbide.

[0043] The stretching rollers 13, 14 are adjustable so that the pressure exerted on the wire during the passage through the machine can be varied.

[0044] The stretching machine 10 comprises actuators 16, in this example associated with the first stretching rollers 13, which allow to vary the distance of the first and / or second stretching rollers 13, 14 with respect to the central axis X and therefore the pressure exerted on the metal wire 100, and possibly position sensors able to measure the position of the first and / or second stretching rollers 13, 14, for example with respect to the central axis X.

[0045] The stretching machine 10 comprises at least two speed sensors 17, 18 disposed upstream and downstream of the stretching rollers 13, 14 to measure the speeds VI, V2 of the metal wire 100 at the entry and exit of the stretching machine 10.

[0046] The stretching machine 10 also comprises a measuring device 20 disposed downstream of the stretching rollers 13, 14 and configured to detect at least one physical quantity D of the metal wire 100 at exit from the machine 10.

[0047] The measuring device 20 is disposed between the stretching rollers 13, 14 and the drawing device 19 along the central axis X.

[0048] This physical quantity D characterizing the metal wire 100 can be detected from different angles with respect to / around the central axis X while the metal wire 100 advances.

[0049] According to possible embodiments, the stretching machine 10 can comprise a measuring device also upstream of the stretching rollers 13, 14 to detect at least one physical quantity D of the metal wire 100 at entry to the machine 10.

[0050] TTiis physical quantity D can preferably be the current diameter.

[0051] Optionally, the current diameter can be suitably processed to obtain a final usable and consistent measurement, such as the nominal or equivalent diameter of the metal wire 100 for example. This is essential in the case of ribbed metal wire 100, since the ribs themselves make the measurement particularly complex.

[0052] The equivalent diameter is a value that represents the cross-section area of the wire, taking into account the rib. In other words, it is the diameter of a smooth wire that would have the same area as the ribbed wire.

[0053] The measuring device 20 is advantageously a single-axis or multiple-axis laser or optical micrometer.

[0054] The stretching machine 10 comprises a processing and control unit 21 operationally connected to the measuring device 20 to receive a first signal SI containing the physical quantity D and a second signal S2’, S2” containing the speed VI, V2 values, to the actuators 16 to send a command signal S3’ to move the first or second stretching rollers 13, 14, and to the drawing device 19 to send a command signal S3” to vary the speed of the metal wire 100.

[0055] The movement of the first or second stretching rollers 13, 14 is functional to vary their current distance with respect to the central axis X. This movement, possibly combined with the variation in speed of the metal wire 100, allows to increase or decrease the pressure exerted thereon and therefore to adjust both the elongation and also the diameter of the wire.

[0056] The processing and control unit 21 comprises a storage module 21a and a processing module 21b.

[0057] The processing and control unit 21 is programmed to run a computer program on the basis of a compensation algorithm stored in the storage module 21a which allows, at least on the basis of values correlated with the first signal SI, with the second signal S2’, S2”, with the density p of the material constituting the metal wire 100, to calculate a current mass flow M, expressible for example in kg / s, and to keep this current mass flow M within certain pre-established limits Mmax and Mmin, for example stored in a specific database in the storage module 21a, possibly generating the command signals S3’, S3” for the actuators 16 and for the drawing device 19.

[0058] This algorithm allows to maintain a minimum mass flow such that both the elongation and also the diameter of the ribbed metal wire 100 remain within ranges established by the standard. This allows to produce a compliant ribbed metal wire 100 with minimal material usage.

[0059] The stretching machine 10 can comprise a user interface 23 connected, physically or wirelessly, to the processing and control unit 21 to display the results, fig- I-

[0060] The user interface 23 can be installed on the machine or can be remotely operated.

[0061] The user interface 23 can be physical, inclusive of screens, possibly touchscreens, keys, knobs, remote controls, or virtual, for example a smartphone and tablet application or a web interface.

[0062] The operation of the stretching machine 10 described heretofore, which corresponds to the method for stretching a ribbed metal wire 100 according to the present invention, comprises the following steps.

[0063] Feeding SI 00 a ribbed metal wire 100 along a central axis X through the two rows of first and second stretching rollers 13, 14.

[0064] Measuring S200, by means of the measuring device 21, a physical quantity D of the ribbed wire 100 at exit from the machine 10 and sending a first signal SI containing said physical quantity D to the processing and control unit 21 and measuring, by means of the speed sensors 17, 18, the speeds VI, V2 of the metal wire 100 at machine entry and exit sending a corresponding second signal S2’, S2”.

[0065] The speed V2 at exit will be increasingly higher than the speed VI at entry, due to the fact that the metal wire 100 is stretched. The same principle also applies to the diameter that undergoes a reduction at exit.

[0066] The physical quantity D is preferably the current diameter of the ribbed wire 100, which is then processed by the processing and control unit 21 to obtain an equivalent diameter measurement.

[0067] Running S300 a computer program on the basis of a compensation algorithm which allows, at least on the basis of values correlated with the first signal SI, with the second signal S2’, S2”, with the density p of the material constituting the metal wire 100, to calculate a current mass flow M, expressible for example in kg / s, and to keep this current mass flow M within certain pre-established limits Mmax and Mmm, for example stored in a specific database in the storage module 21a, possibly generating the command signals S3’, S3” for the actuators 16 and for the drawing device 19.

[0068] Moving S400 the first and / or second stretching rollers 13, 14 to vary the distance with respect to the central axis X by means of the actuators 16 on the basis of the respective command signals S3’, S3”.

[0069] It is clear that modifications and / or additions of parts may be made to the machine for stretching a ribbed metal wire and the corresponding method as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims.

[0070] 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 a machine for stretching a ribbed metal wire and corresponding method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby. 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. Stretching machine (10) for stretching a ribbed metal wire (100), comprising:- two rows, opposite a central axis (X), of first and second idle stretching rollers (13, 14) associated with actuators (16) configured to vary their distance from said central axis (X), and downstream a drawing device (19) suitable to draw said metal wire (100);- at least one measuring device (20) disposed downstream of said stretching rollers (13, 14) configured to detect at least one physical quantity (D) of said metal wire (100), and speed sensors (17, 18) disposed upstream and downstream of said stretching rollers (13, 14) configured to measure a speed (VI, V2) of said metal wire (100);- a processing and control unit (21) configured to run a program which, on the basis of values correlated with a first signal (SI) from said measuring device (20), with a second signal (S2’, S2”) from said sensors (17, 18), with the density p of the material constituting said metal wire (100), allows to calculate a current mass flow (M) and to keep it within certain pre-established limits (Mmax, Mmm), possibly generating command signals (S3’, S3”) for said drawing device (19) and said actuators (16).

2. Stretching machine (10) as in claim 1, characterized in that said processing and control unit (21) comprises a storage module (21a) in which said density p and said mass flow limits (Mmax, Mmm) are stored.

3. Stretching machine (10) as in claim 1 or 2, characterized in that said measuring device (20) is a single-axis or multiple-axis laser or optical micrometer.

4. Stretching machine (10) as in any claim hereinbefore, characterized in that it comprises another measuring device disposed upstream of said stretching rollers (13, 14).

5. Method for stretching a ribbed metal wire (100) which comprises:- feeding (SI 00) a ribbed metal wire (100) along a central axis (X) through two rows of first and second stretching rollers (13, 14),- measuring (S200), by means of a measuring device (20), a physical quantity (D) of said ribbed wire (100) at exit and sending a first signal (SI) containing said physical quantity (D) to a processing and control unit (21) and measuring, by means of speed sensors (17, 18), the speeds (VI, V2) of said metal wire(100) at machine entry and exit,- running (S300) a computer program on the basis of a compensation algorithm which allows, at least on the basis of values correlated with said first signal (SI), with the second signal (S2!, S2”), with the density p of the material constituting said metal wire (100), to calculate a current mass flow (M), and to keep said current mass flow (M) within certain pre-established limits (Mmax, Mmin), possibly generating command signals (S3’, S3”) for said stretching rollers (13, 14) and for said drawing device (19),- moving (S400) said first and / or second stretching rollers (13, 14) to vary the distance with respect to said central axis (X) by means of the actuators (16) on the basis of said command signals (S3’, S3”).

6. Method as in claim 5, characterized in that said physical quantity (D) is the diameter of the ribbed metal wire (100), possibly processed to obtain an equivalent diameter value.

7. A computer-readable data carrier on which the computer program ran (S300) in the method as in one of the claims from 5 to 6 is stored.

Images