Apparatus and method for machining elongate metal elements

Abstract

The apparatus for machining elongate metal elements comprises a drawing device (5) for feeding at least one element (2) in a longitudinal direction (L) according to a feeding direction (A), a bending head (3) suitable to receive the element (2) on a work plane (a). The bending head (3) comprises a bending mandrel (31) and an eccentric pivot (32) operable in rotation on the work plane (a) around the mandrel (31 ). The apparatus also comprises an auxiliary drawing device (5') operating along the longitudinal direction (L) downstream, with respect to the feeding direction (A), of the bending head (3), comprising a first pair of opposite wheels (51) with respect to the longitudinal direction (L) and a second pair (52) of wheels (510, 511, 520, 521) opposite with respect to the longitudinal direction (L).

Description

DescriptionAPPARATUS AND METHOD FOR MACHINING ELONGATE METAL ELEMENTSTechnical field

[0001] The present invention relates to an apparatus for machining elongate metal elements, such as for example iron rods for reinforced concrete, obtained by cutting from bars or rolls.Background of the invention

[0002] The use of elongate metal elements is known, in particular steel bars commonly called "iron", bent at one or the opposite ends, in this latter case called "rebars", or rods bent into a substantially closed section bar, called "stirrups" or "long stirrups" depending on the size, for making reinforcing bars for reinforced concrete, or elements having spacers, called "forks".

[0003] Also used are "curved" irons, i.e. subjected to bending operations with a wide radius of curvature. Radiuses of curvature that are greater than the radiuses of curvature proper to the shape of the bending members are considered wide.

[0004] In order to manufacture such products, special so-called "curving" apparatuses are generally used.

[0005] Known solutions, therefore, do not fully meet the versatility needs of the specific sector and are therefore very expensive.Disclosure

[0006] The aim of the present invention is to solve the problems mentioned in the known art, by devising an apparatus for machining elongate metal elements, which permits to manufacture curved pieces in a versatile manner.

[0007] A further object of the invention is to provide an apparatus with a simple and functional structure, which is reliable in operation and has great flexibility of use.

[0008] The aforementioned objects are achieved, according to the invention, by the method according to claim 1 , and by the apparatus according to claim 9.

[0009] A method for machining elongate metal elements is provided according to the invention, comprising, in a suitable phase relationship, the steps of: a. arranging an apparatus for machining elongate metal elements, comprising a drawing device for feeding at least one element in a longitudinal direction at least according to one feeding direction, a cutting device for cutting the element, arranged downstream of the drawing device, a bending head suitable for receiving the element on a work plane containing the longitudinal direction, the bending head comprising a bending mandrel and an eccentric pivot which can be activated in rotation on the work plane around a central axis of the mandrel, an auxiliary drawing device operating downstream, with respect to the feeding direction, of the bending head, comprising a first pair of wheels opposite to thelongitudinal direction, and a second pair of wheels opposite to the longitudinal direction; b. feeding the element along the longitudinal direction by means of the drawing device in the feeding direction and possibly machining a front portion of the element by actuating, in appropriate phase relationship, the bending head; c. retaining the element fed by the auxiliary drawing device; d. cutting the element to size by the cutting device; e. positioning an initial portion of a rear portion of the element, to be bent, at the bending head by operating the auxiliary drawing device; f. controlling, by means of a control unit, the positioning of the bending pivot in an angular position of curvature around the central axis, suitable for bending the rear portion of the element according to a radius of curvature; g. operating the auxiliary drawing device by means of the control unit, so as to feed the element along the longitudinal direction in a direction opposite to the feeding direction, producing, by means of the abutment on the eccentric pivot rotated in the angular position of curvature, the curvature of the rear portion of the element according to the radius of curvature.

[0010] Rear portion means substantially a part, for example a half, of the cut element, rearwardly arranged according to the feeding direction.

[0011] Advantageously, in step g. the bending said rear portion of said member according to said radius of curvature is carried out while said member is advanced along said longitudinal direction by said auxiliary drawing device in said opposite direction to said feeding direction.

[0012] Preferably, in appropriate relation to the step g. operating the auxiliary drawing device, so as to feed the element in the opposite direction, the method provides for selectively operating at least one wheel of the auxiliary drawing device in an activation motion to position said wheel in a deactivated position, spaced away from the longitudinal direction, so as not to interfere with the already curved front portion of the advancing element.

[0013] The step of selectively operating at least one wheel preferably provides for selectively operating the wheel of the second pair of wheels, preferably outermost with respect to the bending head, arranged below the longitudinal direction.

[0014] Alternatively it is possible to provide that one of the pairs of wheels of the auxiliary drawing device is deactivated by a tightening action on the element, so as not to interfere with it. Such tightening action can be made possible by actuating means, for example of fluid-dynamic or mechanical type, acting on the opposing wheels, and can be adjusted in a manner known in the art, for example, in the case of actuating means of fluid-dynamic type, based on the pressure of an operating fluid feeding said actuating means in a respective actuation circuit. The control unit can then be configured to adjust saidtightening action, for example the pressure of the operating fluid in said circuit, so as to selectively deactivate the pair of opposing wheels, so that the element can remain in contact with them, but in the absence, substantially, of a significant clamping action, so that the element cannot be deformed by them.

[0015] Preferably, the step g. operating the auxiliary drawing device, so as to feed the element in the opposite direction is preceded by the step of operating the lifting of the auxiliary drawing device and of the bending head to avoid interference between the advancing element and members of the apparatus, arranged upstream of the bending head.

[0016] Preferably, during the step g. operating the auxiliary drawing device, so as to feed the element in the opposite direction, the method also provides for operating the auxiliary drawing device and / or the bending head in a relative motion of mutual compensation along a direction transverse to the longitudinal direction, on the work plane, from a first position, in which the bending head and the auxiliary drawing device are aligned along the longitudinal direction, to a compensation position, at which the bending head and the auxiliary drawing device are misaligned with respect to the longitudinal direction, to allow the auxiliary drawing device and the bending head to engage an already curved portion of the element.

[0017] Preferably the compensating motion occurs gradually while the element is being advanced in the opposite direction, starting when a curved portion reaches between the wheels of the auxiliary drawing device and ending when the curved portion reaches the bending head.

[0018] The method preferably also provides in appropriate phase relation for operating the rotation of the eccentric pivot around said central axis when the element is retained stationary by the drawing device or by the auxiliary drawing device, to operate the bending of a respective section of the element.

[0019] The apparatus for machining elongate metal elements, according to the invention comprises a drawing device for feeding at least one element in a longitudinal direction according to a feeding direction, a cutting device and a bending head adapted to receive the element on a work plane containing the longitudinal direction.

[0020] The drawing device can also be used to feed the element in a direction opposite to the feeding direction.

[0021] The bending head comprises a bending mandrel and an eccentric pivot, which can be operated rotating on the work plane around a central axis of the mandrel.

[0022] The apparatus also comprises an auxiliary drawing device, which is operative along the longitudinal direction downstream, with respect to the feeding direction, of the bending head, comprising a first pair of wheels opposed with respect to the longitudinal direction and a second pair of wheels, also opposed with respect to the longitudinal direction.

[0023] Likewise, the auxiliary drawing device may be operated to feed the element in the feeding direction and in the opposite direction.

[0024] The apparatus further comprises a control unit configured to control the positioning of the bending pivot in an angular position of curvature and to control the controlled operation of the auxiliary drawing device so that the element advances in the opposite direction to the feeding direction abutting the eccentric pivot positioned in the angular position of curvature, to produce a curvature of a rear portion of the element.

[0025] According to the invention it is therefore possible to make the curvature of the element with wide radiuses of curvature in small spaces, preferably breaking its execution into a first part and a second part. Preferably it is possible to bend for example respectively the front portion and the rear portion of the element in successive steps thanks to the cooperation of different members per each step. This aim can be achieved thanks to the cooperation of the bending head with the drawing device for bending the front portion, of the bending head with the auxiliary drawing device for bending the rear portion. In this way it is possible to easily create large curved pieces which, to be curved in a single advancement cycle, proceeding from the front end to the rear end, would require machining spaces, which are the wider the greater the radius of curvature.

[0026] The apparatus may further comprise first actuation means for selectively actuating at least one of the wheels of the auxiliary drawing device in an activation motion in an activation direction, from a position in which the at least one wheel is operative on the work plane and a deactivated position, in which the at least one wheel is spaced away from the longitudinal direction, in particular retracted with respect to the work plane, so as not to interfere with the element being processed.

[0027] Preferably the activation direction is transverse, in particular orthogonal, to the work plane. Alternatively or additionally, the activation direction may be on the working plane, transverse to the longitudinal direction.

[0028] Preferably the at least one wheel selectively operable in the activation motion is arranged at a first side, in particular lower one, with respect to the longitudinal direction.

[0029] Furthermore, said wheel is preferably part of the outermost pair of wheels with respect to the bending head, considering the feeding direction.

[0030] The apparatus may comprise second actuation means for actuating the auxiliary drawing device and / or the bending head in a relative motion of mutual compensation in a direction transverse to the longitudinal direction, on the work plane, from an aligned configuration, in which the auxiliary drawing device and the bending head are aligned with respect to the longitudinal direction, to a compensated configuration, in which the auxiliary drawing device and the bending head are misaligned with respect to the longitudinal direction, so as to engage a portion of the element having a radius of curvature. The compensationmotion permits to arrange the bending pivot, the mandrel and the engaging wheels of the auxiliary drawing device in contact with the curved element, misaligning them according to the three points through which the circumference passes having as radius the radius of curvature of the same element.

[0031] Said transverse direction may be substantially perpendicular to the longitudinal direction.

[0032] The second actuation means is preferably configured to drive the auxiliary drawing device or part thereof along special guides.

[0033] Preferably, the second actuation means is preferably configured to actuate also a further wheel along suitable guides in the compensation motion, in particular a wheel of the second pair of wheels, operating at an upper side with respect to the longitudinal direction.

[0034] The control unit may be configured to perform additional steps, such as step e. positioning an initial section of a rear portion of the element, to be curved, at the bending head by operating the auxiliary drawing device.

[0035] Furthermore, the control unit may be configured to perform said step b. feeding said element along said longitudinal direction by said drawing device in said feeding direction. In the event that it is necessary to make a curvature of the front portion of the element, the control unit is configured to work a front portion of said element, in a suitable phase relationship, by means of said bending head.

[0036] Advantageously said control unit comprises a computer and a memory readable by said computer.

[0037] Preferably said memory comprises instructions which, when executed by said computer, cause said apparatus to perform steps f. and g. of the method.

[0038] The present invention also relates to a computer program comprising instructions that cause the apparatus to carry out steps f. and g. of the method, if they are carried out by the control unit of the apparatus.Description of drawings

[0039] The details of the invention will become more apparent from the detailed description of a preferred embodiment of the apparatus for machining elongate metal elements, illustrated by way of example in the accompanying drawings, in which: figures 1 - 5 are respectively a front view of the apparatus according to the invention in successive operating steps; figures 6 and 7 are an enlargement of the apparatus in the steps shown respectively in figures 4 and 5.Description of embodiments of the invention

[0040] With particular reference to these figures, the apparatus for machining elongate metal elements 2, in particular iron rods for reinforced concrete (see in particular Figures 1 - 7), has been indicated as a whole with the reference number 1.

[0041] The apparatus according to the invention permits to machine, in particular to bend or to curve, a plurality of elements 2 at each processing cycle, but it can also be used to machine one element 2 at a time. For simplicity, hereafter a single element 2 will be used to include as well the case of several elements 2 processed simultaneously.

[0042] The apparatus according to the invention allows manufacturing, in particular, at least curved pieces, i.e. deformed with wide radius of curvature at both front and rear ends. "Wide" means a radius of curvature greater than the radius shaped by the bending members, in particular by the pivot or pivots of the mandrel, as defined below.

[0043] The apparatus according to the invention generally permits to manufacture bent and / or curved pieces according to any geometry.

[0044] The apparatus 1 comprises a bending head 3 and a drawing device 5, not shown for simplicity, but indicated in the figure, for feeding the element 2 to the bending head 3 according to a longitudinal feeding direction L and mainly a feeding direction A (see in particular figure 1).

[0045] The drawing device 5 can feed the element 2 also in the opposite direction A’, reversing the direction of rotation of the respective drawing wheels.

[0046] The apparatus also comprises an auxiliary drawing device 5’, operative in succession to the bending head 3 along the longitudinal direction L according to the feeding direction A.

[0047] The drawing device 5 is preferably arranged upstream of the bending head 3 and is preferably protected by a protective coating or casing 50, for example made of suitably shaped metal sheet or other material suitable for the required protection. In practice, the protective coating 50 performs a work shield function.

[0048] The drawing device 5 mainly performs the function of feeding the element 2 in the longitudinal direction L mainly according to the feeding direction A. For example, the drawing device 5 can be made in the form of at least one pair of wheels, at least one of which motorized, opposed with respect to the longitudinal direction L. In particular, the axes of said wheels lie preferably on a same plane orthogonal to the longitudinal direction L.

[0049] The apparatus 1 may further comprise a cutting device 6, preferably arranged along the longitudinal direction L between the drawing device 5 and the bending head 3, for cutting the element 2 to the desired extent.

[0050] The bending head 3 comprises, for example, a bending mandrel 31 and an eccentric pivot 32 operable in rotation on a work plane a substantially around a central axis of the mandrel 31 itself, to bend the element 2. In particular, the eccentric bending pivot 32 can be carried by a respective disk, rotatably mounted around said central axis.

[0051] The mandrel 31 may be made for example of a double pivot, i.e. a pair of pivots arranged on each side of said central axis (see figure 1), or of a single central pivot. In the lattercase the central axis coincides with the axis of the single pivot, while in the presence of a double pivot, the central axis falls in the middle between the two pivots constituting the mandrel 31.

[0052] Between the mandrel 31 and the eccentric pivot 32 or between the two pivots of the mandrel 31 if provided, an insertion channel 33 is defined for the element 2 to be bent, aligned for the bending phase to the longitudinal direction L.

[0053] In practice, according to a first operating mode of bending, the eccentric pivot 32 is configured to bend the element 2 that is inserted inside the channel 33, rotating on the work plane a around the central axis of the mandrel 31 , whatever it is made. In this way the element 2 is bent at the desired angle and the section thus deformed assumes a radius of curvature substantially equal to the radius of the mandrel 31.

[0054] According to a further operating mode, the drawing device 5 and the bending head 3 may advantageously cooperate for manufacturing curved portions, i.e. with a large radius of curvature, of the element 2, in particular with a radius of curvature wider than the radius shaped by the pivot or pivots of the mandrel used. In particular, it is possible to bend with a wide radius of curvature a portion of the element 2 by suitably arranging the bending members of the bending head 3 and operating the advance of the element 2 between them, in the feeding direction A along the longitudinal direction L, so that these bending members act as counterpart in the bending action exerted by the mandrel 31 and the eccentric pivot 32.

[0055] In particular, in order to bend a front portion 2a or head portion of the element 2, the eccentric pivot 32 is arranged in a certain angular position of curvature, downstream, with respect to the longitudinal direction L and to the feeding direction A, of the mandrel 31. When the element 2 is advanced by the drawing device 5 in the feeding direction A (see figure 1 ), the element 2 is continuously engaged and, therefore, curved by the eccentric pivot 32 positioned in said angular position of curvature.

[0056] The auxiliary drawing device 5’ and the bending head 3 may also advantageously cooperate for making curved portions of the element 2. In particular, the auxiliary drawing device 5’ may carry out the bending of a rear portion 2b of the element 2.

[0057] For this purpose, the apparatus usefully comprises a control unit configured to control the positioning of the eccentric bending pivot 32 in an angular position of curvature and to control the controlled actuation of the auxiliary drawing device 5' so that the element 2 advances in the opposite direction A to the feeding direction A against the eccentric pivot 32 positioned in the angular position of curvature, to produce a curvature of the rear portion 2b of the element 2.

[0058] The auxiliary drawing device 5’ preferably comprises a first pair 51 of wheels 510, 511 , which is closer to the bending head 3, and a second pair 52 of wheels 520, 521 , which isfurther downstream of the first pair 51 with respect to the bending head 3. In each pair, a first wheel 510, 520 is provided, arranged at a first, for example upper, side and a second wheel 511 , 521 , arranged at a second, for example lower, side with respect to the longitudinal direction L (see figure 2).

[0059] At least one of the wheels of the auxiliary drawing device 5’ may be selectively movable by an activation motion in an activation direction, transverse to the longitudinal direction L.

[0060] In particular, the activation direction may be substantially and preferably orthogonal to the work plane a or on the work plane transverse to the longitudinal direction L.

[0061] Furthermore, at least part, in particular a pair of wheels, of the auxiliary drawing device 5’ may be movable with respect to the bending head 3 of a compensation motion according to a transverse direction B (see figure 5) to the longitudinal direction L, on the work plane.

[0062] More precisely, at least one pair of wheels, preferably the first pair 51 and preferably the upper wheel 520 of the second pair 52, or integrally all the wheels of the auxiliary drawing device 5’ are preferably actuated by actuation means of known in the art type, in the transverse direction B in said compensation motion, in order to be able to engage a section of the element 2 already having a radius of curvature. In this case, in fact, the section of the element 2 has a course having, in said transverse direction B, a variable quota along the longitudinal development.

[0063] Said compensation motion therefore permits to appropriately misalign, deviating with respect to the longitudinal direction L, for example by an entity C, the relative positioning of the members aimed at engaging the section of the curved element 2, therefore the bending head 3 and the auxiliary drawing device 5’, so as to allow the correct engagement of said section.

[0064] Alternatively, it is possible to provide that the compensation motion is achieved by moving in relative motion with respect to the auxiliary drawing device 5’ the same bending head 3 along the transverse direction B.

[0065] Furthermore, at least one of the wheels of the second pair 52 of the auxiliary drawing device 5', for example the second wheel 521 , is preferably actuated selectively by relative actuation means in said actuation motion, between an active position on the work plane a, at which it can cooperate with the element 2 thereon, and a deactivated position, spaced apart from the longitudinal direction L, in particular retracted with respect to said work plane a, at which it does not interfere with the element 2 lying on the work plane itself. Alternatively, the deactivated position may also be obtained by selectively moving, on the work plane a in the transverse direction B, the wheel 521 from the longitudinal direction L to a non-interference position.

[0066] The activation motion is useful to avoid interference or forcing of the already curved piece during the curvature of the rear portion 2b of the element 2, between the members of theauxiliary drawing device 5’ and the already curved front portion 2a (see figure 3).

[0067] The auxiliary drawing wheels 5’ can be further simultaneously activated in a manner known in the art, from an inactive position, below the work plane, to an active position, on the work plane.

[0068] In a manner known in the art, it is possible to provide for moving the additional drawing device 5’ and the bending head 3, so as to bring the work plane a and the longitudinal direction L on a level emerging from the other operating members, in particular from the drawing device 5, so that the relative encumbrance does not interfere with the advance of the element 2 in the opposite direction A’ of supply.

[0069] The operation of the apparatus according to the invention is understandable from the above description.

[0070] In an initial preparation step, or after having made one or more bends on one end of the element 2, the bending head 3 is arranged to curve with a certain radius of curvature R the front portion 2a of the element 2.

[0071] In particular, the eccentric pivot 32 is positioned in an angular bending position, suitable for engaging a portion of the element 2 to be bent according to the given bending radius R. The auxiliary drawing device 5' is positioned in the inactive position, below the work plane so as not to interfere with the curvature of the front portion 2a of the element.

[0072] The element 2 is therefore fed by the drawing device 5. The advance along the longitudinal direction L in the feeding direction A against the eccentric pivot 32 in the angular position of curvature causes the curvature of the front portion 2a of the element 2 or of a portion thereof, depending on the extent of the advance with respect to the longitudinal development of element 2 (see figure 1 ).

[0073] Subsequently, preferably when element 2 has advanced halfway, the eccentric pivot 32 is positioned in a disengagement position with respect to element 2.

[0074] The element 2 is then advanced further along a straight section, not yet curved or bent, along the longitudinal direction L (see figure 2). This advance proceeds at least until a straight portion of the element 2 reaches the auxiliary drawing device 5', so that the latter can engage the straight portion.

[0075] The drawing device 5 and the auxiliary drawing device 5' are then preferably operated in this step in a synchronized manner to advance the element 2 being worked for the entire development necessary for accomplishing the piece according to the desired geometry. In practice, the advance ends when the element 2 reaches the cutting device 6 at a portion to be cut.

[0076] At the end of the advance, in fact, the cutting device 6 cuts the element 2 to size.

[0077] Possible bending cycles can then be carried out at the end of the rear portion 2b of the element 2, with the cooperation of the bending head 3 and the auxiliary drawing device 5'.

[0078] Subsequently, the auxiliary drawing device 5' positions an initial section, with respect to the opposite direction A', of the rear portion of the element 2 at the bending head 3, to carry out the curvature.

[0079] For this purpose, the eccentric pivot 32, upon command of the control unit, is arranged in the angular position suitable for bending the rear portion 2b of the element 2 according to a radius of curvature R' which can usually, but not exclusively, be equal to the radius of curvature R with which the front portion 2a has been curved, at least in part.

[0080] If necessary, in a suitable phase relationship, but simultaneously, the auxiliary drawing device 5' and the bending head 3 can be moved to a higher level or height than the drawing device 5 or the cutting device 6, carrying with they the work plane a, in order to avoid interference between the rear portion 2b of the element 2 and the encumbrance of the members upstream of the bending head 3, in particular of the drawing device 5, during the movement of the element 2 in the bending step.

[0081] Subsequently, the auxiliary drawing device 5' is actuated by means of the control unit, so as to feed the element 2 along the longitudinal direction L in the opposite direction A' to the feeding direction A, producing, by means of the abutment on the rotated eccentric pivot in the angular position of curvature, the curvature of the rear portion 2b of the element 2 according to the radius of curvature R' (see figure 3).

[0082] Before the already curved front portion 2a reaches the auxiliary drawing device 5', due to the effect of the advance in the opposite direction A', preferably the second wheel 521 of the second external pair 52 is selectively actuated according to the activation motion in the deactivated position 521a, in particular for example rearward, so as not to interfere with it (see figures 4 and 6). The remaining wheels of the auxiliary drawing device 5', on the other hand, remain operative in respective active positions on the work plane a, in particular the wheel 520, which in this bending step can, in a suitable position, equally contribute to carrying out a contrasting action even in the absence of the opposite wheel 521 , arranged in the deactivated position.

[0083] Alternatively, it is possible to provide that the second wheel 511 of the first pair of wheels 51 is moved as a result of the activation motion into the deactivated position.

[0084] Alternatively it is possible to provide that one of the pairs of wheels 51 , 52 of the auxiliary drawing device 5’ is deactivated by a clamping action on the element 2, so as not to interfere with it. This clamping action can be made possible by actuator means, for example of the fluid dynamic or mechanical type, acting on the wheels 51 , 52, and can be adjusted in a manner known in the art, for example, in the case of actuator means of the fluid dynamic type, on the basis to the pressure of an operating fluid which feeds said actuator means in a respective actuation circuit. The control unit can then be configured to adjust said clamping action, for example the pressure of the operating fluid in said circuit,so as to selectively deactivate the pair of opposing wheels, so that the element 2 can remain in contact with them, but in the absence, substantially, of a significant clamping action, so that the element 2 cannot be deformed by them.

[0085] Finally, the auxiliary drawing device 5' and / or the bending head 3 are preferably actuated in the compensation motion along the transversal direction B, to allow the element 2 to be correctly engaged at the respective curved portions (see figures 5 and 7). In particular, the active wheels of the auxiliary drawing device 5', for example the wheels of the first pair 51 and the upper wheel of the second pair 52, and the bending head 3 can be arranged in a relative compensation configuration, i.e. misaligned with respect to each other to the other relative to the longitudinal direction L. For example, the active wheels 510b, 511b, 520b of the auxiliary drawing device 5' or alternatively the bending head 3 can be moved in this compensation motion to be brought into said compensation configuration, to interact correctly with a curved section of the element 2. In this circumstance, for example, the drawing device 5' is therefore brought from a first position 5'a to a second, compensated position 5'b, due to the effect of this compensation motion (see figures 5 and 7).

[0086] The compensation motion can usefully occur gradually. It can substantially begin when the already curved front portion 2a reaches the first pair of wheels 51 and ends when said already curved front part 2a reaches the mandrel 31 , in the step of cooperation between the bending head 3 and the auxiliary drawing device 5' which perform the advance of the element 2 in the opposite direction A'.

[0087] The compensation motion has the function of adapting the arrangement of the members which engage element 2 to the geometry of the latter, in particular if this is curved. Therefore, in particular, the compensation motion avoids forcing an already curved section of the element 2 into a rectilinear geometry, such as the arrangement of the bending head 3 and of the auxiliary drawing device 5' would appear in the absence of this motion, which engage the same section.

[0088] The apparatus 1 therefore allows the machining of the element 2 in an effective manner. In particular, the apparatus allows to easily carry out the bending and / or curvature of the front and rear portions of the same element 2.

[0089] In particular, the apparatus allows to carry out the bending of opposite ends of the element through the cooperation of the bending head and the auxiliary drawing device, without the need for a suitable bending assembly.

[0090] In the practical embodiment of the invention, the materials used, as well as the shape and dimensions can vary according to the needs.

[0091] Should the technical features mentioned in any claim be followed by reference signs, such reference signs were included strictly with the aim of enhancing the understanding of the claims and hence they shall not be deemed restrictive in any manner whatsoever on thescope of each element identified for exemplifying purposes by such reference signs.

Claims

A method for machining elongate metal elements, characterized in that it comprises the steps of: a. providing an apparatus for machining elongate metal elements, comprising a drawing device (5) for feeding at least one said element (2) in a longitudinal direction (L) at least according to a feeding direction (A), a cutting device (6) for cutting said element (2), arranged downstream of said drawing device (5), a bending head (3) adapted to receive said element (2) on a work plane (a) containing said longitudinal direction (L), said bending head (3) comprising a bending mandrel (31 ) and an eccentric pivot (32) which can be activated in rotation on said work plane (a) around a central axis of said mandrel (31 ), an auxiliary drawing device (5') operating downstream, with respect to said feeding direction (A), of said bending head (3), comprising a first pair (51) of wheels (510, 511) opposite with respect to said longitudinal direction (L), and a second pair (52) of wheels (520, 521) opposite with respect to said longitudinal direction (L); b. feeding said element (2) along said longitudinal direction (L) by means of said drawing device (5) in said feeding direction (A) and possibly work in a suitable phase relationship, by means of said bending head (3), a front portion (2a) of said element (2); c. retaining said element (2) fed by said auxiliary drawing device (5'); d. cutting the element (2) to size by said cutting device (6); e. positioning an initial portion of a rear portion (2b) of the element (2) to be bent, at the bending head (3) by operating the auxiliary drawing device (5’); f. controlling, by means of a control unit, the positioning of said bending pivot (31) in an angular position of curvature around said central axis, suitable for curving said rear portion (2b) of said element (2) according to a radius of curvature (R'); g. operating said auxiliary drawing device (5'), by means of said control unit, so as to feed said element (2) along said longitudinal direction (L) in an opposite direction (A) to said feeding direction (A), producing, by means of the abutment on said eccentric pivot (32) rotated in said angular position of curvature, the curvature of said rear portion (2b) of said element (2) according to said radius of curvature (R'). The method of claim 1 , wherein said step g. the bending said rear portion (2b) of said element (2) according to said radius of curvature (R') is carried out while said element (2) is advanced along said longitudinal direction (L) by said auxiliary drawing device in said opposite direction (A) to said feeding direction (A). The method of claim 1 or 2, wherein in a suitable relation to said step g. operating said auxiliary drawing device (5'), so as to feed said element (2) in said opposite direction (A), provides for selectively operating at least one said wheel of said auxiliary drawing device (5') in an activation motion to position said wheel (511 , 521 ) in a deactivated position(521b), spaced away from said longitudinal direction (L), in order not to interfere with said front portion (2a), if curved, of said advancing element (2). The method of claim 3, wherein said step of selectively actuating at least one said wheel provides for selectively actuating said wheel (521 ) of said second pair of wheels, outermost with respect to said bending head (3), arranged below said longitudinal direction (L). The method of any one of claims 1 - 4, wherein said step g. operating said auxiliary drawing device (5') so as to feed said element (2) in said opposite direction (A'), is preceded by the step of operating the lifting of said auxiliary drawing device (5') and said bending head (3) to avoid interference between said advancing element (2) and members of said apparatus (1 ), arranged upstream of said bending head (3). The method of any one of claims 1 - 5, wherein said step g. operating said auxiliary drawing device (5') so as to feed said element (2) in said opposite direction (A') also provides for operating said auxiliary drawing device (5') and / or said bending head (3) in a relative motion of mutual compensation along a transversal direction (B) to said longitudinal direction (L), on said work plane (a), from a first position, in which said bending head (3) and said auxiliary drawing device (5') are aligned along said longitudinal direction (L), to a compensation position (5'b), at which said bending head (3) and said auxiliary drawing device (5') are misaligned with respect to said longitudinal direction (L), to allow said auxiliary drawing device (5') and said bending head (3) to engage an already curved portion of said element (2). The method of claim 6, wherein said compensation motion takes place gradually while said element (2) is advancing in said opposite direction (A), starting when said curved portion (2a) reaches between said wheels (510b, 511b, 520b) of the auxiliary drawing device (5') and ends when said curved portion (2a) reaches said bending head (3). The method of any one of claims 1 - 7, wherein it also provides, in a suitable phase relationship, for operating the rotation of said eccentric pivot (32) around said central axis when said element (2) is held stationary by said drawing device (5) or by said auxiliary drawing device (5'), to carry out the bending of a respective section of said element (2). Apparatus for machining elongate metal elements, comprising at least one drawing device (5) for feeding at least one said element (2) in a longitudinal direction (L) at least according to one feeding direction (A), a cutting device (6), a bending head (3) adapted to receive said element (2) on a work plane (a) containing said longitudinal direction (L), said bending head (3) comprising a bending mandrel (31 ) and an eccentric pivot (32) operable in rotation on said work plane (a) around a central axis of said mandrel (31), an auxiliary drawing device (5') operating along said longitudinal direction (L) downstream, with respect to said feeding direction (A), of said bending head (3), comprising a first pair (51 )of wheels (510, 511) opposite with respect to said longitudinal direction (L) and a second pair (52 ) of wheels (520, 521) opposite with respect to said longitudinal direction (L), characterized in that it comprises a control unit configured to perform steps f. and g. of the method according to claim 1 or 2. The apparatus of claim 9, wherein it comprises first actuation means for selectively actuating at least one of said wheels (510, 511 , 520, 521 ) in an activation motion in an activation direction, transversal or parallel to said work plane (a), from an active position, in which said at least one wheel (521 , 511) is operative on said work plane (a) to a deactivated position, spaced away from said longitudinal direction (L), in which said at least one wheel (521 ) does not interfere with said element (2) being machined. The apparatus of claim 10, wherein said activation direction is substantially orthogonal to said work plane (a). The apparatus of claim 10 or 11 , wherein said at least one wheel (521 , 511 ) which can be selectively actuated in said activation motion is arranged on a first side, in particular the lower, with respect to said longitudinal direction (L). The apparatus of any one of claims 9 - 12, wherein it comprises second actuation means for actuating said auxiliary drawing device (5') and / or said bending head (3) in a relative motion of mutual compensation in a direction (B) transversal to said longitudinal direction (L), on said work plane (a), from an aligned configuration, in which said auxiliary drawing device (5') and said bending head (3) are aligned with respect to said longitudinal direction (L), to a compensated configuration, in which said auxiliary drawing device (5') and said bending head (3) are misaligned with respect to said longitudinal direction (L), engaging a portion of said element (2) having a radius of curvature (R, R'). The apparatus of claim 13, wherein said second actuation means is configured to actuate at least one pair of said wheels (510, 511 ) or both pairs (51 , 52) of said auxiliary drawing device (5'). The apparatus of claim 14, wherein said transversal direction (B) is perpendicular to said longitudinal direction (L). The apparatus of claim 14 or 15, wherein said second actuation means is configured to actuate said auxiliary drawing device (5') or part of it along suitable guides. The apparatus of any one of claims 9 - 16, wherein said control unit comprises a computer; a data carrier readable by said computer, comprising instructions which, when executed by said computer, cause said apparatus to execute steps f. and g. of the method according to claim 1 or 2. Computer program comprising instructions which cause the apparatus of any one of claims 9-17 to carry out steps f. and g. of the method according to claim 1 or 2.

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