ITBO20100083A1 - METHOD AND EQUIPMENT FOR STRAIGHTENING IRON AND SIMILAR ROUNDS - Google Patents

Description

Description

METHOD AND EQUIPMENT FOR STRAIGHTENING IRON RODS E

SIMILAR

Technical field

The present invention relates to a method and an apparatus for straightening iron rods and the like, as well as the product thus obtained.

Known art

It is known that iron rods, used in particular to make reinforcement for reinforced concrete, are frequently obtained from rods prepared in rolls and unwound by respective reels to be worked in special operating machines. Such machines generally comprise apparatuses equipped with suitable straightening members. The straightening members usually consist of operating members adapted to act on the advancing metal rod before it reaches the subsequent processing stations, for example the cutting station and sometimes subsequently the bending station. In practice, these apparatuses are able to eliminate both the lack of straightness of the rod and the curvature caused by the winding in the form of a reel. To this end, the straightening members subject the rod to suitable bending actions of such intensity as to overcome the elastic limit of the material, so as to substantially eliminate this curvature and make the straightening effect permanent. Different types of apparatuses for straightening iron rods are currently known. According to a widely known typology, illustrated for example in documents EP 0459869 and EP 0947256, the straightening equipment comprises one or more straightening units consisting of pairs of counter-rotating wheels, sometimes also grooved, opposite to the axis of the rod, to adequately engage the rod itself fed in advance between them. The counter-rotating wheels are arranged in succession and on parallel axes. For example, such known equipment can provide a first straightening unit and a second straightening unit, suitable for correcting mainly corresponding components of the curvature of the metal rod, in particular on perpendicular planes, for example on a horizontal and vertical plane. . The counter-rotating wheels gradually correct the curvature of the rod, acting from opposite sides with respect to the advancing rod, so as to force the latter to assume a substantially damped sinusoid profile, which finally assumes a rectilinear course.

However, equipment with counter-rotating wheels does not allow to obtain a very accurate straightening of the iron rods, but on the other hand have the advantage of minimizing the surface alterations of the rod which, in the case of the iron rod for reinforced concrete, is specially designed for comply with certain characteristics assessed on the basis of a parameter defined â € œadherence indexâ €. This type of straightener is commonly referred to as a â € œroller straightenerâ €.

In a different type of straightening apparatus, called rotor, the straightening members are inserted inside a rotating member or rotor, able to be rotated around an axis substantially coinciding with the direction of advancement of the rod. According to a known solution, illustrated for example in documents EP 0880415 and EP 1952906, the rectifying members used in these rotors consist of inserts or blades distributed radially inside the rotor, so as to act by rotating bending on the iron rod in crossing. In practice, each straightening element presses and slides on the rod by effect of the rotational motion of the rotor and the forward motion of the rod, consequently correcting the curvature of the rod in all the lying planes. However, these apparatuses have the drawback of requiring frequent replacements of the straightening members, due to the considerable friction that develops in the relative motion between the inserts or blades and the rod to be straightened. Furthermore, the continuous sliding action between the straightening members and the iron rod risks unacceptable damage to the ribs specially made on the surface of the rod, flattening them beyond a limit value of the aforementioned adhesion index imposed by the regulations of the sector.

The aforementioned sliding action still involves a considerable dispersion of energy, which can be found in the sensitive and widespread heating of the straightened piece. It is also necessary to consider that in this type of equipment the iron rod to be straightened is stressed by a rotating bending action that derives from the application of loads distributed over the entire length and directly applied to the surface of the rod through the parts. rectifiers. This can locally cause states of stress, yielding or plasticization, which can alter the mechanical characteristics of the straightened piece in an unacceptable way.

In a further different known solution, illustrated for example in the document EP 1952906, the straightening members present inside the rotor consist of rollers rotating according to suitably inclined axes with respect to the longitudinal axis of advancement of the rod. In these rotors, also called hyperbolic, the straightening elements roll on the external surface of the rod to be straightened, so as to considerably reduce the effects of wear deriving from friction.

The hyperbolic rotor solution reduces the risk of surface damage to the rod typical of the aforementioned devices with insert or lamella rotors, replacing the sliding and rotating bending action exerted by the latter with corresponding rolling rolling actions. The straightening obtained is also of considerable precision, with particular reference to the geometric tolerance requirements imposed by the regulations of the specific sector.

However, even the solution with hyperbolic rotors has drawbacks, attributable to the fact that the rod to be straightened is subjected to considerable stresses exerted directly and widely by the rotating rollers or bushings, which can alter the mechanical characteristics of the straightened piece.

Finally, both rotor and hyperbolic rotor equipments have drawbacks when used in combination with bending equipments. In fact, the rotor assemblies have a considerable inertia and therefore it is difficult to stop them in order to carry out any bending operation. To obviate this drawback, avoiding the need to stop the rotating components, cutting is often carried out by means of so-called â € œvolantiâ € systems which however present a considerable complexity.

Presentation of the invention

The task of the present invention is to solve the aforementioned problems, devising a method capable of effectively straightening iron rods and the like, keeping their mechanical and surface characteristics substantially unchanged and optimally allowing subsequent processing and application.

Within this aim, a further object of the present invention is to devise an apparatus capable of implementing the cited method in an optimal manner.

Another object of the present invention is to provide a method and an apparatus which allow to reduce the energy consumption necessary for straightening the iron rods.

Another object of the present invention is to provide an apparatus of simple conception, as well as having a safe and versatile use.

Not least object of the present invention is to provide a product obtained by means of the aforementioned method, in particular consisting of a straightened rod with a substantially rectilinear course.

The aforementioned purposes are achieved, according to the present invention, by the method for straightening iron rods and the like according to claim 1, as well as by the apparatus according to claim 6 and by the product according to claim 16.

Brief description of the drawings

The details of the invention will become more evident from the detailed description of a preferred embodiment of the apparatus for straightening iron rods and the like, illustrated by way of example in the accompanying drawings, in which:

Figure 1 shows a schematic front view of the apparatus for straightening iron rods and the like according to the invention;

Figures 2A, 2B, 2C and 2D show respective schematic side views of the apparatus in question, according to different embodiments;

Figures 3 to 6 show respective front views of the apparatus in question in subsequent operating phases;

Figures 7 and 8 respectively show a schematic front view of the apparatus for straightening iron rods according to further embodiments;

figure 9 schematically shows the product obtained by means of the apparatus according to the invention;

Figures 10A, 10B and 10C respectively show a schematic front view of the apparatus in successive operating steps of a different embodiment of the method in question.

Embodiments of the invention

With particular reference to these figures, the apparatus for straightening iron rods 2 according to the invention has been indicated together with 1.

The apparatus 1 comprises means 3 for the advancement of the rod 2 along a longitudinal axis 23 of advancement intended to coincide with the longitudinal axis of the straightened rod (Figures 3 and 8), as better explained below. The advancement means 3 can be for example of the known type with counter-rotating rollers (Figure 3).

According to the present invention, the apparatus 1 provides for bending means 4 arranged on opposite sides with respect to the longitudinal axis of the rod 2 to be straightened. As schematically represented in Figure 1, the bending means 4 comprise respectively a first series of teeth 5a and a second series of teeth 5b adapted to urge the iron rod 2 to be straightened from opposite sides.

The first series of teeth 5a is adapted to be supported by a first support 6a, while the second series of teeth 5b is adapted to be supported by a second support 6b. Between the first series of teeth 5a and the second series of teeth 5b a portion of at least one rod 2 to be straightened is interposed, oriented according to the aforementioned longitudinal advancement axis 23.

The teeth 5a and 5b are arranged in a staggered manner with respect to the longitudinal axis of the iron rod 2 interposed between them, so that the undulations impressed on the rod itself compensate each other. The teeth 5a, 5b are therefore preferably distributed evenly, with substantially constant pitch, on the respective supports 6a, 6b, so that the longitudinal offset A, B between each tooth of one series and the next tooth of the other series is repeated in a substantially unchanged manner along the interposed rod section (Figure 1) to obtain the aforementioned mutual compensation. Basically, as specified below, the compensation line of the broken line obtained as a result of the action of the bending means is such as to get as close as possible to the ideal axis of the straight rod to be obtained, the relative undulations being such as to do not exceed the limits of acceptability of the specific product. Furthermore, it is preferable that these longitudinal staggers A, B are substantially equal, so as to intercept equidistant sections of the aforementioned portion of the interposed rod 2 and produce, by using the bending means 4, a succession of symmetrical undulations of the section of the rod. intercepted, as better explained below. Each tooth 5a, 5b provides a base 7 for connection to the respective support 6a, 6b and an end portion 8, preferably of a pointed shape or in any case with a decreasing front section, capable of intercepting a respective cross section 9 of the iron rod 2. Each suitably spaced series of teeth 5a, 5b is therefore able to interact in a spaced, ie discretized, way on the interposed iron rod 2, acting only on the intercepted cross sections 9. In other words, the spaced arrangement of the teeth 5a, 5b on the supports 6a, 6b makes it possible to selectively stress the rod 2 in the straightening phase, that is, in correspondence with only the intercepted cross sections 9, leaving instead the portions of 2 intermediate rod.

The end portion 8 of each tooth 5a, 5b preferably has a transverse fold profile 10, shaped so as to act on several spaced points of the intercepted cross section 9. According to a preferred embodiment shown in Figure 2A, each fold profile 10 is defined by a pair of fold segments 11 converging and symmetrical with respect to a median longitudinal plane. Each bend segment 11 is therefore able to intercept in use a corresponding surface portion 12 of the rod 2, ideally point-like or in any case of very reduced extension. Obviously, different conformations of the profile 10 can be provided, for example with a polygonal section defined by a greater number of segments 11 or of another shape.

The shape of the profile 10 of the teeth 5a, 5b determines the radial orientation of the stresses acting discreetly on the rod 2 to be straightened at the contact points. More precisely, the orientation of the interactions operating at only the intercepted cross sections 9 is substantially perpendicular to the plane of tangency identified by each of the segments 11 gripping the rod 2.

According to further embodiments represented respectively in Figures 2B, 2C, 2D, the teeth 5a, 5b can provide a plurality of profiles 10 arranged transversely in succession. Each profile 10 is thus able to receive a respective rod 2 for simultaneously straightening it.

The apparatus 1 also comprises actuation means, known per se and therefore for simplicity not shown in the figures, adapted to actuate the first series of teeth 5a and the second series of teeth 5b in reciprocal motion so as to subject the rod 2 of iron interposed to corresponding opposite bending actions.

According to the embodiment shown in Figures 3 to 6, the actuation means are adapted to actuate the first support 6a and the second support 6b in a relative reciprocating translation motion, in order to bring them together and move away from each other. For example, the first support 6a can be fixedly arranged, while the second support 6b can be translated alternatively between an adjacent configuration (Figures 3 and 5) and a distanced configuration (Figures 4 and 6) according to the direction indicated by the arrow C of the figures to be 3 to 6. Alternatively, it is possible to provide that only one support, for example the first support 6a, is movable, while the second support 6b is fixed, or that both supports 6a, 6b are movable.

In any case, in correspondence with the approached configuration, the interposed rod 2 is clamped with a predetermined force between the teeth 5a and 5b or, more precisely, it is clamped by the teeth 5a, 5b only in the surface areas 12. Therefore, as a result of this pinching or gripping, the rod 2 is stressed to localized bending actions in correspondence with only the intercepted cross sections 9.

Thanks to the offset and opposite displacement, the teeth 5a, 5b are able to be reciprocally approached in a transverse direction to the advancement axis 23 beyond the advancement axis 23 itself (Figures 3, 5, 8), giving rise to a a sort of interpenetration between the teeth 5a, 5b, able to operate on the rod 2 a predetermined and controlled longitudinal succession of folds. For each portion straightened according to the method and apparatus described, the rod 2 is substantially bent around the end portion 8 of each tooth 5a, 5b active in the aforementioned pinching. This localized bending action occurs in the absence of reciprocal sliding between the teeth 5a, 5b and the rod 2. In other words, the relative speed between the active portions of the teeth 5a, 5b and of the clamped cross sections 9 is substantially zero during the actuation phase described.

Overall, the section of rod 2 intercepted and clamped undergoes a particular deformation characterized by a wavy shape, the width of which 22, determined at will based on the dynamic and structural parameters of the bending means 4, is repeated regularly on opposite sides of the axis length of the rod 2 (see figure 9). The amplitude 22 of this wavy shape has the further characteristic of having an algebraic sum for each pair of successive waves or loops 21 such as to cancel each other out with a compensating straightening effect. More precisely, if the longitudinal offset A, B between the teeth 5a, 5b is equal and constant, this wavy shape is regular. As illustrated in Figure 1, due to the effect of the substantially regular width 22 of the loops 21, the wavy conformation of the rod 2 obtained following the action of the bending means 4 can approximate with good precision a substantially rectilinear course. It is therefore possible to obtain the desired tolerance by suitably varying the pitch and the width of the undulation. In the distanced configuration of the supports 6a, 6b, the iron rod 2 thus shaped is made free from the grip of the teeth 5a, 5b themselves and released from any localized compression action to allow the subsequent advancement.

The aforementioned advancement means 3, preferably placed upstream of the bending means 4, feed the rod 2 in a suitable phase relationship with respect to the movement of moving away and approaching the supports 6a, 6b. In particular, the advancement means 3 are adapted to operate the stepwise advancement of the rod 2 being processed when this is free from the grip of the teeth 5a, 5b and the supports 6a, 6b are in the removed configuration (see figures 4 and 6). According to a preferred, particularly advantageous embodiment, shown in Figure 7, the advancement means 3 are integrated with the bending means 4 and at the same time feed and operate the teeth 5a and 5b to continuously straighten the iron rod 2 . More precisely, the teeth 5a, 5b are fixed to flexible supports, for example of the belt or chain type, so as to constitute respective track elements. A first track 60a is therefore provided carrying the first series of teeth 5a and a second track 60b to which the second series of teeth 5b is fixed. The first track 60a and the second track 60b are respectively wound on feed and drive means 13 constituted by pairs of wheels 30. These wheels 30 are capable of being rotated continuously. Each track wound on the wheels 30 defines an active branch 14a, 14b and an inactive branch 15a, 15b, both of which are substantially straight. The respective active branches 14a, 14b of the first track 60a and of the second track 60b are arranged facing each other substantially parallel, so as to receive between them a rod 2 in the aforementioned deformed wave configuration. More precisely, the winding of the tracks 60a, 60b on the wheels 30 is made in such a way as to produce a certain offset, preferably constant and regular, between the teeth 5a and 5b. By virtue of this offset, the teeth 5a, 5b of the active branches 14a, 14b are arranged with the respective end portions 8 projecting transversely beyond the longitudinal axis 23 of advancement, in a sort of mutual interpenetration suitable for determining the wavy deformation described previously, through discrete bending actions. The continuous actuation of the wheels 30 is able to produce the progressive grip of only the transverse sections 9 of the rod 2, the progressive bending of corresponding portions of the rod 2 around the end portion 8 of each tooth 5a, 5b, as well as the Progressive and continuous advancement of the rod 2 by advancing the portion being gripped.

As in the embodiment illustrated in Figures 3 to 6, also in this case, but due to a continuous forward motion instead of an alternating translation motion, each tooth 5a, 5b is subjected to an alternating approaching motion and reciprocal separation, respectively in the sections of the tracks 60a, 60b wound to the wheels 30 upstream and downstream of the active branches 14a, 14b, for gripping or pinching and releasing corresponding cross sections 9. In the same way, in fact, the teeth 5a, 5b cause inflections, that is bends, in alternately opposite directions on the portion of rod 2 interposed along the active branches 14a, 14b, producing as an effect the controlled deformation in waves which results in the straightening of the rod 2.

In particular, it should be noted that the contact between the teeth 5a, 5b of the active branches 14a, 14b and the respective intercepted cross sections 9 takes place, as in the embodiment described above, without sliding, therefore with substantially zero relative speed. Furthermore, it is important to note that the insertion and release of a section of rod 2 between the active branches 14a, 14b takes place due to the continuous rotation of the wheels 30 which produces the approaching and distancing of the teeth 5a, 5b in the branches of the tracks wound on the wheels. The intercepted cross sections 9 are therefore gripped by the folding means 4 and brought forward along the active branches 14a, 14b.

It is also important to note that the contact between the bending means 4 in advance and the inserted rod 2 is limited only to the intercepted cross sections 9. Therefore, in the ideal case in which the contact occurs in a point-like manner on the surface of the rod 2, no substantial relative motion takes place between said bending means 4 and the rod 2. In fact, unlike a rolling motion, the contact of the bending means 4 operated in motion it is discontinuous, that is, intended to involve only spaced and discrete sections of the rod 2.

According to a constructive variant not shown, the two branches 14a and 14b, or part of them, could not be parallel or even not straight in order to facilitate the insertion and straightening operations of the rod.

According to a further embodiment, it is possible to provide in a particularly advantageous way a plurality of pairs of tracks 60a, 60b as described above, also acting on different planes of the rod 2 to be straightened. For example, a first pair of tracks can be able to act on a plane according to the described method, while a second pair of tracks, inclined with respect to the previous one, is able to act on an inclined plane, preferably orthogonal, with respect to the previous one, for a Optimal straightening of particularly difficult rods or of significant transverse dimensions. The effect of the bending action on multiple planes involves a further compensation of the undulated trend of the product thus obtained, with an overall reduction in the width of the loops or waves and therefore a geometrically more precise straightening.

According to a different embodiment shown in Figure 8, the apparatus 1 can carry out the straightening of rods 2 by means of the discretized gripping and bending action operated by teeth carried by respective toothed wheels 50a, 50b driven in continuous rotation. More precisely, the apparatus comprises at least a first toothed wheel 50a and a second toothed wheel 50b, bearing teeth 5a, 5b of the type described above, opposite each other with respect to the interposed rod 2. The rod is moved forward thanks to the continuous rotation of the wheels 50a, 50b themselves. The first toothed wheel 50a and the second toothed wheel 50b are arranged with their teeth mutually offset, so as to achieve, as previously described, the straightening resulting from the alternating and compensated deflection of successive sections of the rod in crossing. More precisely, in this case the resulting straightening effect is obtained by the localized and discontinuous pinching operated by the teeth carried by respective facing portions of the toothed wheels. It is obviously possible to provide several pairs of toothed wheels 50a, 50b acting in succession on the rod 2, as shown.

It is also possible to arrange the apparatus according to the invention as a combination of two or more of the embodiments described, suitably arranged in series. For example, it is possible to provide in series to arrange first rectifying members consisting of toothed wheels 50a, 50b and second rectifying members consisting of pairs of tracks 60a, 60b as previously described.

In any case, the product 20 obtained by using the apparatus according to one of the illustrated embodiments has a wavy shape with regular loops 21, with a width 22 reduced at will, which approximates and has the effects of a round rod. perfectly straight development (fig. 9). In this wavy shape the loops 21 are arranged in a repeated and regular manner around a substantially rectilinear longitudinal axis of symmetry 23 due to the fact that the algebraic sum of the loops 21 with respect to the aforementioned axis of symmetry 23 is capable of canceling each other out with a compensating effect of straightening. In particular, the wavy shape with regular loops of the product 20 obtained also has the effects of a sufficiently straight rod, as it allows the easy and regular rolling of the rod on any flat surface, so-called â € œeasy rotateâ €, as in use in the empirical habits of the specific sector for the evaluation of the suitability for the use of such products.

The method for straightening iron rods and the like according to the invention is easily understood from the above description.

The iron rod 2 to be straightened is fed by the feeding means, separated or integrated into the system, according to a longitudinal advancement direction and inserted stepwise or continuously between the bending means 4.

By means of the controlled activation of the actuation means, the opposing and staggered teeth 5a, 5b are actuated in engagement on corresponding cross sections 9, causing transverse bending stresses, discretized and from opposite sides along the longitudinal axis of the rod 2. These controlled stresses are able to eliminate the bends from the rod 2, producing an undulation whose amplitude 22 is controlled and transversely compensated, with a substantial straightening effect of the rod 2 itself. The extent and development of this undulation can in fact be controlled on the basis of the construction and adjustment parameters of the bending means 4, for example on the basis of the amount of bending stress imposed and the conformation of the teeth 5a, 5b.

The subsequent actuation of the bending means 4, intermittent or continuous according to the embodiment, determines in any case the release of the section of rod 2 thus straightened and the insertion of a new section of rod 2 to be straightened between the folding means 4 themselves, respectively alternately or continuously.

According to a preferred embodiment of the method in question, useful in particular for straightening rods having important transverse dimensions or particularly twisted initial conditions, it is possible to provide for the advancement of the rod 2 by a section corresponding to a multiple of the pitch or of a fraction thereof between the teeth 5a, 5b, so as to subject the same cross sections 9 to repeated bending actions from alternately opposite sides, thus strengthening the compensation effect of the residual stresses in the rod 2 being processed.

In practice, a first straightening step acts on a transverse section 9 by a tooth of the first series 5a of teeth, carrying out a first bending operation of the rod 2; following the advancement of the rod 2, the same cross section 9 is subjected to the action of a tooth of the second series 5b of teeth, opposed to the first.

In particular, by advantageously operating a second bending staggered by half a step in the longitudinal direction, as can be seen in figures 10A, 10B and 10C, it is possible to substantially eliminate the residual corrugation. This has a considerable advantage in cases where the residual ripple, however small, can in any case cause problems.

Basically, this subsequent action has the purpose of making a counter-fold of the rod 2, i.e. a fold according to the opposite direction of bending to that of the fold made in the same section 9 by the previous folding means, in order to eliminate in whole or in part the characteristic undulations of the discretized straightening system described above. In practice, after making the first bend (Figure 10A), the rod is advanced for a distance equal to half a step, as indicated by the dashed line 2a in Figure 10B; at this point, by carrying out a second fold or counter-fold in correspondence with the same sections 9 (Figure 10C), the substantial elimination of the residual corrugation is obtained.

Naturally, it is possible to provide that the aforesaid first fold and second fold or counter fold, offset by half a pitch, are made by differently shaped folding means, as previously stated. In particular, the first fold can be provided by first straightening members consisting of pairs of tracks 60a, 60b and the second fold or counter-folding by second rectifying members consisting of toothed wheels 50a, 50b. Advantageously, in this case, the pairs of tracks 60a, 60b also perform the function of advancing the rod. Basically, the first straightening means and the second straightening means are spaced apart in such a way that the loops impressed on the rod are offset by half a step so that the undulations created to straighten the rod by the first are substantially eliminated by the second straightening means.

The method for straightening iron rods and the like according to the invention allows the straightening of iron rods and the like to be carried out effectively, keeping their mechanical characteristics substantially unchanged and allowing their subsequent processing in an optimal way. This purpose is achieved thanks to the discretized and controlled action of the bending means 4. In particular, these bending means 4 are adapted to act in a controlled manner on discrete cross sections 9, spaced from each other in a suitable way, so as to produce in the rod 2 a corrugated deformation suitable to represent the straightening of the rod 2 itself. In fact, the deformation resulting from the action of the bending means 4 is given by an undulation of controlled amplitude 22, that is, as small as desired, in relation to the tolerances of the specific sector of application, compensated as a whole by each side of the rod being processed and the whose average axis therefore has a substantially straight course.

A prerogative of the invention is given by the fact that the action of the bending means 4 is represented by concentrated transverse stresses, ideally punctual or at least extended to surface areas 12 of reduced extension of the rod 2. This minimizes the overall dynamic actions exercised on the rod during the straightening phase and therefore reduces the energy consumption of this process and implicitly also any alterations introduced in straightening. In other words, unlike the known straightening methods, the action of the bending means 4 is not diffused along the entire rod 2, but only involves discretized sections of the rod 2.

This involves a considerable reduction in the risk of deterioration of the mechanical characteristics and of the surface quality of the same, overcoming an important disadvantage of traditional methods, in which instead the rod to be straightened is subjected to continuous sliding or rolling actions suitable in any case to involve each section of the rod. In particular, the contact operated by the bending means 4 according to the invention is discretized and discontinuous along the longitudinal development of the rod 2.

Furthermore, the method according to the invention and the equipment that implements it, have the characteristic of subjecting only certain sections of the rod to be straightened to bending actions, thus considerably reducing both the risk of damage to the same and the ™ energy needed for the process. Consequently, the surface state of the rod also benefits, resulting substantially unchanged compared to how it is made in the steel mill. On the other hand, known straightening methods and apparatuses have the common characteristic of indiscriminately subjecting each section of the rod to be straightened to a dynamic action of alternating bending which subjects the material to a so-called "fatigue" stress. This â € œfatigueâ € stress, deriving from continuous bending and counter-bending actions that degrade the mechanical characteristics of the material to a greater extent compared to the maximum stress suffered, obviously has a significant impact on energy expenditure.

The innovative form of straightening object of the present invention, unlike the known art, has the peculiar characteristic of subjecting only certain sections of the rod to be straightened to bending action, thus considerably reducing both the risk of damage to the same, which the energy needed for the process. Furthermore, the surface of the rod also benefits considerably, remaining substantially unchanged compared to how produced by steel mills.

It is also important to note that the bending action operated by the apparatus according to the invention takes place in an operating condition in which the relative speed between the teeth 5a, 5b and the corresponding intercepted cross sections 9 is substantially zero. The absence of any mechanical sliding action further reduces the amount of heat developed during straightening and preserves the surface integrity of the rod 2, in particular the state of the surface ribs whose dimensional characteristics, especially in relation to the transverse protrusion, must comply with current regulations.

It should be noted that the method for straightening iron rods according to the invention is very versatile. In fact, it is possible to adapt the operating phases, as well as the dynamic and constructive parameters involved, to operate the optimal straightening of any type of rod. In particular, as previously described, it is possible to adjust the actuation of the bending means 4 with the advancement of the rod 2, so as to provide a counter-fold of the rod 2 to straighten particularly twisted or particularly twisted rods 2 in an optimal and repeatable way. particular dimensions.

Finally, it should be pointed out that the product 20 obtained by means of the method according to the invention represents a very precise straightening result. In particular, the straightened rod as described has a wavy pattern, reproduced in succession in a precise way, with regular waves of constant amplitude reduced at will, the amplitudes of which compensate each other, therefore capable of approximating a development substantially straight line of the median axis. Furthermore, the product is free from deterioration of the surface and mechanical characteristics by virtue of the bending carried out in a discontinuous way, that is, discretized, according to the method object of the invention, to create the aforementioned waves.

In the practical implementation of the invention, the materials used, as well as the shape and dimensions, can be any according to requirements.

Where the technical characteristics mentioned in each claim are followed by reference signs, these reference signs have been included for the sole purpose of increasing the understanding of the claims and consequently they have no limiting value on the purpose of each element identified by way of ™ example from such reference marks.

Claims (17)

Claims 1) Method for straightening iron rods and the like, characterized by subjecting the rod (2) to be straightened to the action of bending means (4) able to act discreetly in correspondence with a plurality of cross sections (9), suitably spaced along a longitudinal axis (23) of said rod (2), on opposite sides with respect to said longitudinal axis (23), so as to make on the same rod (2) a corresponding plurality of folds with curvature in the opposite direction with respect to said longitudinal axis (23), such as to determine an undulating development with loops (21) presenting as a whole a substantially rectilinear course. 2) Method according to claim 1, characterized by the fact of advancing said rod (2) to subject said cross sections (9) of the same rod (2) to a further action of said bending means (4), such as to realize in the said transverse sections (9) corresponding counter-folds, having curvature in the opposite direction with respect to the direction of the folds previously made. 3) Method according to claim 2, characterized in that it provides for the advancement of said rod (2) by a portion corresponding to a half pitch of said wavy loop extension (21) of said rod (2), in in order to substantially eliminate the residual ripple. 4) Method according to claim 1 or 2, characterized in that it comprises the following operating steps: to. feeding at least one said rod (2) according to said longitudinal advancement axis (23); b. interposing a portion to be straightened of said rod (23) between said bending means (4) adapted to act discreetly alternatively on opposite sides in correspondence with said longitudinally spaced cross sections (9) of said portion of rod (2); c. actuate in motion said folding means (4) from an inactive configuration deviating from said cross sections (9) to an active configuration approached in contact with said cross sections (9), able to stress said cross sections (9) up to a condition of substantial reciprocal interpenetration of said bending means (4) in a direction transverse to said longitudinal advancement axis (23), to achieve said wavy loop development (21) of said portion of the interposed rod (8). d. returning said bending means (4) to said inactive configuration away from said cross sections of said rod (2). 5) Apparatus for straightening iron rods and the like, characterized in that it comprises means (3, 30) for advancing the rod (2) to be straightened along a longitudinal axis (23) of advancement; bending means (4) adapted to act discreetly in correspondence with a plurality of transverse sections (9) of said rod (2), suitably spaced along said longitudinal advancement axis (23) of said rod (2), arranged from parts opposite with respect to said longitudinal axis of advancement (23), and movable between a departed inactive configuration and an active configuration approached in contact with said cross sections (9); actuation means adapted to actuate in motion said folding means (4) alternatively between said inactive configuration which is displaced and said active configuration approached in contact with said cross sections (9), so as to realize on the same rod (2) a corresponding plurality of folds with curvature in the opposite direction with respect to said longitudinal axis (23), such as to determine an undulating development with loops (21) presenting a substantially rectilinear course. 6) Apparatus according to claim 5, characterized in that said folding means (4) comprise a first series of teeth (5a) and a second series of teeth (5b) carried by respective support means (6a, 6b), opposite each other in discontinuous and staggered manner with respect to said longitudinal axis (23) of said rod (2) to be straightened, said teeth (5a, 5b) comprising an end portion (8) capable of intercepting a respective cross section (9) of the rod (2 ). 7) Apparatus according to claim 6, characterized in that said teeth (5a, 5b) have in correspondence of said end portion (8) a transversal fold profile (10), shaped in such a way as to act substantially on several spaced points of a said cross section (9). 8) Apparatus according to claim 7, characterized in that said transverse bend profile (10) is defined by a pair of bend segments (11) converging and symmetrical with respect to a median longitudinal plane. 9) Apparatus according to claim 7, characterized in that said teeth (5a, 5b) comprise a plurality of profiles (10) arranged transversely in succession, to receive a corresponding plurality of rods (2) to be straightened. 10) Apparatus according to claim 6, characterized in that said support means (6a, 6b) comprise flexible supports bearing said teeth (5a, 5b) so as to form a respective first track element (60a) and a second element to track (60b), wound on continuously advancing and driving means (13), said first track element (60a) and said second track element (60b) being equipped with respective active branches (14a, 14b), in correspondence with which said teeth (5a, 5b) are facing, staggered and at least partially interpenetrated in a transverse direction to said longitudinal axis of advancement (23), for the realization of said wavy loop development (21) of said rod (2). 11) Apparatus according to claim 10, characterized by the fact that said active branches (14a, 14b) are arranged converging according to the direction of advancement of the rod (2), to facilitate its insertion and straightening operations. 12) Apparatus according to claim 6, characterized in that said teeth (5a, 5b) are offset by respective opposed toothed wheels (50a, 50b) suitable to be driven in continuous rotation motion for straightening said rod (2 ) interposed. 13) Apparatus according to claim 6, characterized in that said actuation means are adapted to actuate said teeth (5a, 5b) carried by said first support (6a) and by said second support (6b) in a relative reciprocating translation motion , of approaching up to a sort of interpenetration in the direction transversal to said longitudinal axis (23) of advancement, and of reciprocal separation, in a suitable phase relationship to said advancement means (3) adapted to be driven in step. 14) Apparatus according to claim 5, characterized in that it comprises first folding means suitable for making a first fold in correspondence with said plurality of cross sections (9) of the rod (2) and second folding means arranged in series with said first folding means and adapted to subject the same cross sections (9) of the rod (2) to a further action to make corresponding counter-folds, having curvature in the opposite direction with respect to the direction of the previously made folds. 15) Apparatus according to claim 14, characterized in that said second bending means are arranged offset with respect to said first bending means by a portion corresponding to a half pitch of said wavy wavy development (21) of the rod (2), so to substantially eliminate the residual ripple. 16) Apparatus according to claim 14 or 15, characterized in that said first and second folding means respectively comprise track elements (60a, 60b), provided with teeth (5a, 5b), and / or toothed wheels (50a, 50b) opposed. 17) Product obtained by the method for straightening iron rods and the like according to one of claims 1 to 4, characterized in that it has a wavy shape with regular loops (21), of width (22) reduced at will, which approximates and has the effects of a rod with a perfectly rectilinear development, said loops (21) being repeatedly arranged around an axis of longitudinal symmetry (23) substantially rectilinear due to the fact that the algebraic sum of the loops (21) with respect said longitudinal axis of symmetry (23) is adapted to cancel each other reciprocally with a compensating straightening effect.