Method and apparatus for making stirrups

Abstract

The method for manufacturing stirrups, in particular large ones, starting from elongated metal elements, such as metal profiles and rods in bars or rolls, comprises the steps of: a. feeding a said metal element (20) along a feed direction defined above a bending plane (11); b. performing one or more successive bends on said metal element (20) on said bending plane (11); c. upon reaching a predetermined number of bends, cutting the stirrup (2) thus formed from said metal element (20) fed along said feed direction; d. in a suitable phase relationship, activating support means (6) suitable for engaging and supporting at least one side of said stirrup (2) in formation.

Description

[0001] Description

[0002] METHOD AND APPARATUS FOR MAKING STIRRUPS

[0003] Technical field

[0004]

[0001] The present invention relates to a method and apparatus for manufacturing stirrups, in particular large stirrups, intended for reinforcing building structures.

[0005] Prior art

[0006]

[0002] Apparatus for processing elongated metal elements, in particular metal profiles and similar products in bars or rolls, for producing products such as open or closed profile stirrups and shaped stirrups, also known in the specific sector as long stirrups or diaphragms, are known.

[0007]

[0003] Such apparatus, also known as stirrup forming machines and / or shaping machines, usually comprise at least one bar drawing assembly and at least one bending assembly, a cutting shear and, if the raw material is in rolls, at least one straightener. In particular, the drawing assembly generally consists, for example, of one or more pairs of counter-rotating wheels, at least one of which is motorized, opposed to a direction of feed of the elements to be fed. The bending assembly, on the other hand, consists, for example, of a bending head comprising a central mandrel or a template, around which a bending pin and an abutment can be rotated on a respective bending plane. The elements fed to the bending head can thus be subjected to one or more successive bending operations to produce the shaped products.

[0008]

[0004] European patent EP 2 714 296 of the same applicant illustrates, for example, an apparatus for making two-dimensional and three-dimensional stirrups, comprising guiding means for feeding a metal rod along a feed direction, which also act as abutments during the bending step; a first bending assembly comprising a first central bending mandrel and a first eccentric bending pin rotatable around the first central mandrel for bending the metal rod on a work surface.

[0009]

[0005] In the sector in question, the production of large stirrups, such as long stirrups or diaphragms, is often problematic. It is well known that stirrups are preferably produced by performing all the bends in sequence. This means that, as the bends are performed, the free section that has been formed is dragged along and becomes longer and longer. For this reason, the operating speed must be progressively reduced due to the "flapping" of the piece being formed, which can permanently and undesirably deform the piece itself. This often causes operators to accompany the piece during certain steps of the operating cycle; however, this is an operation prohibited by workplace safety regulations due to its dangerous nature.

[0010]

[0006] The problem is more pronounced the larger the stirrups to be produced and the smaller the section of the raw material being processed, forcing the machine to operate at lower speeds. For this reason, it is currently preferable to produce larger stirrups with shaping machines that are capable of bending both the head and tail of the bars, thanks to the presence of an additional drawing assembly located downstream of the bending assembly. This facilitates processing because it reduces the number of bends to be made in sequence and therefore the "flapping" length, making it possible to maintain a higher average speed and productivity.

[0011]

[0007] However, the solutions currently available do not meet current production and safety requirements, particularly when large stirrups have to be produced. In this case, under the effect of their own weight, the sides of the stirrup deform and cannot be gripped by automatic gripping means, as the sides of the stirrups are not where they would be expected to be according to the theoretical geometry.

[0012]

[0008] Furthermore, when the bends are made all on one side, which is the only way to produce stirrups with conventional stirrup welding machines, and the closing hooks are bent at 135° to the previous side, as required by most international technical standards, including European ones, instead of the traditional 90°, once all the bends have been completed and before cutting, the stirrup to be gripped would have its main sides oriented at approximately 45° and, moreover, in a non-flat area of the machine. This further complicates the gripping of the stirrup by automated gripping means.

[0013]

[0009] European patent application EP 0 882 529 illustrates an apparatus for making stirrups comprising means for gripping and supporting the lower side of the stirrup being formed, which can be rendered inactive if necessary. However, these gripping and supporting means cannot perform the function of restoring the geometry deformed by the weight of the stirrup being processed.

[0014]

[0010] Another problem reported in the sector concerned relates to the cutting step, which in stirrup forming machines is performed by trimming at the end of the bending process. If the stirrup is to be gripped by automated gripping means, this must be done before cutting, when the formed stirrup is still attached to the raw material, in order to know where it is located. However, when cutting is carried out with the stirrup gripped, a real "whiplash" effect is exerted on the members, compromising their strength; this stress is directly proportional to the cross-section of the raw material.

[0015]

[0011] Ultimately, there is a need in the sector in question for making large stirrups for reinforcing building structures in such a way as to solve the problems mentioned above.

[0016] Disclosure

[0017]

[0012] The task of the present invention is to solve the aforementioned problems by devising a method and apparatus for optimally manufacturing stirrups, in particular large ones, for reinforcing building structures.

[0018]

[0013] Within the scope of this task, a further aim of the present invention is to provide a method and apparatus for manufacturing stirrups, in particular large stirrups, which make it possible to limit the deformation of the sides of the stirrups during processing and to restore their correct geometry.

[0019]

[0014] Another purpose of the present invention is to provide a method and apparatus for producing large stirrups which allow said stirrups to be easily gripped by automatic gripping means.

[0020]

[0015] A further purpose of the present invention is to provide a method and apparatus that allow a substantial reduction in the time required to produce the stirrups and therefore an increase in productivity.

[0021]

[0016] A further purpose of the present invention is to provide a method and apparatus that allow the produced stirrup to be placed in an ergonomic and safe collecting position for the operator, in the event that the collecting is not carried out by automatic means.

[0022]

[0017] Another purpose of the present invention is to provide an apparatus for manufacturing large stirrups of simple construction and design, which is safe and reliable in use and relatively inexpensive.

[0023]

[0018] The aforementioned purposes are achieved, according to the present invention, by the method for manufacturing stirrups, in particular large ones, according to claim 1.

[0024]

[0019] The method for manufacturing stirrups, in particular large ones, from elongated metal elements, such as metal profiles and rods in bars or rolls, comprises the steps of: a. feeding a said metal element along a feed direction defined above a bending plane; b. performing one or more successive bends on said metal element on said bending plane; c. upon reaching a predetermined number of bends, cutting said metal element fed along said feed direction.

[0025]

[0020] Preferably, said bending plane is suitably inclined with respect to the longitudinal vertical plane of the apparatus.

[0026]

[0021] According to one embodiment of the invention, the method in question involves feeding the metal element along the feed direction until all the material necessary for the production of the stirrup in formation has been developed, and then cutting the metal element.

[0027]

[0022] The method in question involves making one or more head bends on said metal element and subsequent tail bends, alternating longitudinal movements of the same metal element along said feed direction.

[0028]

[0023] The method in question involves feeding said metal element along said feed direction by means of feed means arranged along the same feed direction.

[0029]

[0024] The method in question involves performing said head bends by feeding said metal element by means of a first drawing assembly arranged upstream of the means for bending said metal element.

[0030]

[0025] The method in question involves gripping the metal element fed along the feeding direction by means of a second drawing assembly arranged downstream of the bending means in order to perform the tail bends.

[0031]

[0026] According to the present invention, the method in question provides for the additional step of d. activating, in a suitable phase relationship, support means capable of engaging and supporting at least one side of said stirrup in formation.

[0032]

[0027] Advantageously, said step of engaging and supporting at least one side of said stirrup in formation involves activating support means that are movable between a first deactivation position retracted below said bending plane, so as not to interfere with the bending steps of said metal element, and a second activation position protruding from the same bending plane.

[0033]

[0028] Advantageously, said step of engaging and supporting at least one side of said stirrup in formation comprises d1. In a suitable phase relationship, activating first support means that can be retracted and moved transversely, said first support means being suitable for being actuated with alternating motion in a direction transverse to said direction of feed of the metal element on said bending plane.

[0034]

[0029] According to one aspect of the invention, said first transversely movable support means are suitable for engaging and supporting at least one upper side of said stirrup in formation, with reference to the inclination of said bending plane.

[0035]

[0030] Advantageously, said step of engaging and supporting at least one side of said stirrup in formation provides for activating second axial support means, arranged aligned along said direction of feed of said metal element.

[0036]

[0031] According to one embodiment of the invention, the method in question provides for preventing any deformation of the lower side of the stirrup being formed, due to its own unsupported weight, by arranging said second axial support means to intercept said lower side of the stirrup being formed, in order to maintain the correct geometry of the part of the stirrup being formed.

[0037]

[0032] It should be noted that in this way the stirrup assumes a shape equal to or close to the theoretical one, with a tolerance such that any automatic gripping system, even of a known type, would be able to grasp the stirrup produced with the required reliability.

[0038]

[0033] Advantageously, the method in question comprises the further step of e. gripping said stirrup by means of automatic gripping means to unload the stirrup from said bending plane.

[0039]

[0034] If, on the other hand, there is no automatic gripping system, the stirrup produced must usually be gripped manually by an operator, which is difficult both because of its weight and because of the raised position in which it is released, which is not very ergonomic for the operator. It is not advisable to allow the stirrup produced to fall by gravity, both for safety reasons and because the stirrup itself could become deformed.

[0040]

[0035] To overcome this problem, the method in question involves using the first means of support, which can be moved transversely, to accompany the stirrup to a predetermined lower position, where it can be left resting on a special shelf or on the ground.

[0041]

[0036] It should be noted that, after the stirrup has been released and rests on a special shelf or on the ground, special sensing devices, such as a laser scanner, allow the operating area of the apparatus to be checked, and the apparatus can then start a new work cycle, while the operator can safely and ergonomically remove the previously deposited stirrup.

[0042]

[0037] The present invention also concerns an apparatus for making stirrups and shaped elements, in particular large ones, from elongated metal elements, such as metal profiles and rods in bars or rolls, in particular for reinforced concrete.

[0043]

[0038] Advantageously, this apparatus is a shaping machine configured to bend said metal elements at both the head and tail ends.

[0044]

[0039] The apparatus for making stirrups, in particular large ones, from elongated metal elements, such as metal profiles and rods in bars, comprises means for feeding a said metal element along a feed direction defined above a bending plane configured by a frame of the same apparatus; bending means operable on said metal element for making one or more successive bends, developed on said bending plane; cutting means suitable for cutting the stirrup thus formed from the metal element fed along the feeding direction, upon reaching a predetermined number of bends.

[0045]

[0040] Advantageously, the apparatus comprises control means for automatically controlling the various operating steps.

[0046]

[0041] According to the present invention, the apparatus for making stirrups comprises support means suitable for being activated in a suitable step relationship with the formation of said stirrup by said bending means to engage and support at least one side of said stirrup in formation.

[0047]

[0042] In particular, said support means are movable between a first deactivation position retracted below said bending plane, so as not to interfere with the bending steps of said metal element, and a second activation position protruding from the same bending plane, to support said at least one side of the stirrup being formed.

[0048]

[0043] According to one aspect of the present invention, said support means comprise first transversely movable support means, adapted to be actuated with controlled motion in a direction transverse to said direction of feed of the metal element on said bending plane.

[0044] In particular, said first support means transversely movable are adapted to be actuated on said bending plane between an upper position and a lower position, said first support means transversely movable being adapted to engage and support an upper side of the stirrup being formed in said upper position and, if necessary, to accompany said stirrup in said lower position for transfer of the same stirrup to a discharge station.

[0049]

[0045] In particular, said first transversely movable support means are actuated between said upper position and said lower position in a configuration emerging with respect to said bending plane.

[0050]

[0046] It should be noted that the trajectory of said first transversely movable support means intersects with the deformed geometry of the stirrup, whatever it may be, and this inevitably causes the transversely movable support means, in the raised position, to intercept the upper side of the stirrup in order to reposition it in the correct theoretical geometry.

[0051]

[0047] Preferably, said first transversely movable support means are designed to be slidable along respective guides arranged at slots made on said bending plane. Said first transversely movable support means are designed to be slidable along said respective guides simultaneously or in sequence.

[0052]

[0048] Preferably, said support means comprise second axial support means, arranged aligned along said feeding direction of said metal element.

[0053]

[0049] According to another aspect of the invention, the apparatus comprises abutment means adapted to compensate for any deformation of the lower side of the stirrup, no longer supported by said second axial support means, but supported and moved vertically by the first transversely movable support means until the theoretical geometry is restored, bringing the same lower side to abut against said abutment means. The abutment means are constituted, for example, by the support floor of the machine.

[0054]

[0050] Preferably, said abutment means are arranged longitudinally in the lower part of said bending plane.

[0055]

[0051] Preferably, said abutment means are tiltable between a retracted disengagement position and a protruding position with respect to said bending plane.

[0056]

[0052] The present invention also relates to a metal stirrup, in particular of large dimensions, intended for use in the construction industry, having closing hooks arranged at 135°. The closing hooks further comprise a last bent side designed to bring the sides of the stirrup back to a substantially horizontal and vertical orientation at the end of the operation.

[0057]

[0053] In this configuration, even if deformed by the weight of the stirrup itself, it is possible to engage the first transversally movable support means to intersect with the deformed geometry of the stirrup and bring it substantially back to its theoretical geometry.

[0058]

[0054] This procedure and this stirrup are useful when using a stirrup forming machine or a shaping machine without using an additional drawing assembly located downstream of the bending assembly.

[0059]

[0055] Advantageously, this additional bend defines a straight section inclined at 45° to the side preceding it.

[0060]

[0056] It should be noted that in order to generate this additional side, it is necessary to make an additional bend. Although irrelevant, it is preferable that the size of this additional side be reduced to the minimum possible by reversing the feed direction before gripping the stirrup by automatic means and then cutting it from the raw material.

[0061]

[0057] The method for manufacturing metal stirrups equipped with a 135° closing hook, in particular large stirrups, starting from elongated metal elements, such as metal profiles and rods in bars or rolls, comprises the steps of:

[0062] - feeding a said metal element along a feed direction defined above a bending plane using only the main drawing;

[0063] - performing all the bends on said metal element in succession on said bending plane;

[0064] - performing a further bend of the appropriate size;

[0065] - if necessary, moving the stirrup being processed backwards by activating a first drawing assembly located upstream of the bending means, reversing its direction;

[0066] - in a suitable step relationship, activate support means capable of engaging and supporting at least one side of said stirrup being formed;

[0067] - if necessary, gripping the stirrup with gripping means;

[0068] - cutting the said metal element;

[0069] - if necessary, accompanying the stirrup thus obtained to a lower level in an unloading station by means of the said support means.

[0070]

[0058] Preferably, said additional bend is made at 45° if the closing hooks are made at 135°.

[0071]

[0059] It should be noted that said steps of

[0072] - making a further bend of the appropriate size, in particular at 45° if the closing hooks are made at 135°; and

[0073] - if necessary, moving the stirrup being processed backwards by activating a first drawing assembly located upstream of the bending means, reversing its direction allow the sides to be repositioned vertically and horizontally to allow any automatic gripping means to easily intercept the stirrup after the deformed geometry has been restored to the theoretical geometry thanks to the intervention of the said first transversally movable support means.

[0074] Brief description of the drawings

[0075]

[0060] The details of the invention will be more evident from the detailed description of a preferred embodiment of the apparatus for manufacturing stirrups, in particular large stirrups, according to the method in question, illustrated by way of example in the accompanying drawings, in which: figures 1 to 14 show, respectively, a side view of a portion of the apparatus for producing stirrups according to the present invention, in successive operating steps;

[0076] Figure 15 shows a front view of the stirrup made according to the present invention.

[0077] Description of embodiments of the invention

[0078]

[0061] With particular reference first to these figures, 1 indicates an apparatus for making stirrups 2, in particular large stirrups, from elongated metal elements 20, such as metal profiles and rods in bars or rolls, hereinafter also referred to as bars for simplicity.

[0079]

[0062] Advantageously, said apparatus 1 is a shaping machine configured to bend said metal elements 20 at both the head and tail ends.

[0080]

[0063] For illustrative purposes, reference is made below to a single-wire machine, but the method of the invention is also applicable to double-wire machines and beyond, for processing a plurality of stirrups simultaneously.

[0081]

[0064] Advantageously, the apparatus is equipped with a control unit 7 for automatically managing the various operating steps.

[0082]

[0065] The apparatus 1 comprises a frame 10 having a substantially longitudinal development. The frame 10 defines a work plane 11 on which the metal elements 20 intended for forming the stirrups 2 are bent. Preferably, said bending plane 11 is suitably inclined with respect to the longitudinal vertical plane of the apparatus. However, the orientation of the bending plane 11 can be any, for example horizontal or vertical, depending on requirements.

[0083]

[0066] The work surface 11 of the apparatus is associated with means 3 for feeding a said metal element 20 along a feed direction A defined above said bending surface 11 ; bending means 4 for performing one or more successive bends on said metal element 20 developed on said bending surface 11 ; cutting means 5 suitable for cutting the stirrup 2 thus formed from said metal element 20 fed along said feed direction A, in appropriate step relationship with the achievement of a predetermined number of bends and / or the appropriate advances.

[0084]

[0067] The feeding means 3 comprise at least one bar drawing assembly consisting, for example, of one or more pairs of counter-rotating wheels, at least one of which is motorized, opposed with respect to the said feeding direction of the metal elements 20, and possibly at least one straightening member.

[0085]

[0068] The bending means 4 comprise at least one bending assembly 40 comprising a bending template or a central bending mandrel 41 and an eccentric bending pin 42 rotatable about the template or the central mandrel 41 to bend the metal element 20 on a bending plane 11.

[0086]

[0069] Advantageously, the feed means 3 comprise a second drawing assembly 31 arranged downstream of the bending assembly 40, in the direction of advance of the metal element 20, and adapted to cooperate with the advance of the same metal element 20. The second drawing assembly 31 is arranged in line with or parallel to the aforementioned feed direction A of the metal element 20. Preferably, the second drawing assembly 31 is configured to exit the bending plane 11 during the active steps.

[0087]

[0070] The cutting means 5, which are known per se, are arranged at the outlet of a protective casing 30 of the feed means 3.

[0088]

[0071] According to the present invention, the apparatus comprises, downstream of the bending assembly 40 in the direction of advance of the metal element 20, support means 6 capable of being activated in a suitable step relationship with the formation of the stirrup 2 by the bending means 4, to engage and support at least one side of the stirrup 2 being formed.

[0089]

[0072] In particular, the support means 6 comprise first axial support means 60, arranged in line along the feed direction A of the metal element 20, and second transversely movable support means 61 , suitable for being actuated with alternating motion in a direction transverse to said feed direction A.

[0090]

[0073] Both the axial supports 60 and the transversely movable supports 61 are retractable below the bending plane 11 so as not to interfere with the metal element 20 in motion during the processing steps. More specifically, the support means 6 are movable between a first deactivation position and a second activation position in which the same support means 6 protrude from the bending plane 11 .

[0091]

[0074] As described below, the axial supports 60 protrude from the bending plane 11 , in the protruding activation position, before the arrival of the piece, so that the latter slides over them in support; the transversally movable supports 61 protrude from the bending plane 11 in a suitable step relationship with the bending of the metal element 20, when the stirrup 2 is substantially formed, at a height lower than the side to be supported of said stirrup, which side may be deformed due to the effect of gravity. In particular, the transversely movable supports 61 rise back up onto the bending plane 11 , even in different ways from each other, supporting the said side of the stirrup 2 and positioning it according to the theoretical geometry, which is not influenced by its own weight or by manufacturing imperfections.

[0092]

[0075] The axial supports 60 comprise at least one support member with alternating motion between said first deactivation position and said second activation position to support at least one lower side 21 of the stirrup 2 being formed. In the case illustrated in the drawings, the axial supports 60 comprise a plurality of support members arranged substantially aligned along the bending plane 11 in the direction of feed A of the metal element 20. Alternatively, the axial supports 60 may be made of a single concealed bracket of suitable length, not shown in the drawings for simplicity.

[0093]

[0076] The transversely movable supports 61 comprise one or more support members suitable to be actuated with alternating motion in a direction transverse to the feed direction A of the metal element 20 to support an upper side 22 of the stirrup being formed, so as to restore the correct geometry of the stirrup 2 if this side 22 is deformed due to its own weight.

[0094]

[0077] It should be noted that the trajectory of the transversely movable supports 61 intersects with the deformed geometry of the stirrup, whatever it may be, and this inevitably causes the transversely movable supports 61 in the raised position to intercept the upper side of the stirrup in order to reposition it in the correct theoretical geometry.

[0095]

[0078] In particular, said transversely movable supports 61 are designed to be slid along respective guides 62 made on the bending plane 11 in a direction transverse to the feed direction A of the metal element 20.

[0096]

[0079] The operation of the apparatus for making stirrups, in particular large stirrups, from elongated metal elements, according to the method of the invention, is easily understood from the above description.

[0097]

[0080] In a known manner, the metal element 20 is fed by the drawing assembly 3 along the feed direction A defined above the bending plane 11 so as to engage the bending assembly 40 (figure 1). The bending assembly 40 performs one or more successive bends on the metal element 20, alternating bending and advancing steps of the workpiece being formed (figures 2 and 3).

[0098]

[0081] It should be noted that during these bending steps, the axial supports 60 are arranged in the first deactivation position, hidden below the bending plane 11 , so as not to interfere with the movements of the metal element 20 being bent, particularly in the case where the stirrup to be produced also requires downward bends.

[0099]

[0082] If necessary, when the dimensions of the piece being formed are close to reaching the position of the axial supports 60 or in any case in a suitable step relationship with the bending steps, the same axial supports 60 are activated in the second activation position, protruding with respect to the bending plane 11 , so as to support the side 21 of the stirrup 2 formed or in the process of being formed, advancing along the feed direction (figure 4). More advantageously, it is possible to provide for the use of the second drawing assembly 31 which protrudes from the bending plane 11 , downstream of the bending assembly 40, and cooperates in the advancement of the metal element 20. The second drawing assembly 31 is arranged in line or parallel to the aforementioned feed direction A of the metal element 20.

[0100]

[0083] It should be noted that the axial supports 60 are suitably spaced apart from each other along the aforementioned feed direction A of the metal element 20. In this way, it is possible to provide adequate support to the aforementioned side 21 of the stirrup 2 formed or in the process of being formed, preventing excessive deformation due to the weight of the stirrup itself.

[0101]

[0084] In the presence of the second drawing assembly 31 , when the predetermined number of bends is reached on the front or head side of the metal element 20, the metal element 20 is fed along the feed direction A by an amount equal to the length required to complete the stirrup 2 being formed; the stirrup 2 is thus separated from the metal element 20, activating the cutting means 5 arranged upstream of the bending assembly 40 (figure 5).

[0102]

[0085] It should be noted that, in this step, the stirrup being formed is already gripped by the second drawing assembly 31 and supported by the axial supports 60. In this configuration, the stirrup being formed is completed with the remaining bends, alternating the movements imposed in the opposite direction by the second drawing assembly 31 and bends in the opposite direction, preferably by the same bending assembly 40.

[0103]

[0086] In an appropriate step relationship, the axial supports 60 can also be activated dynamically and gradually, for example during the bending steps, following the movement of the metal element 20, to dampen and / or limit uncontrolled flapping and gradually accompany the support area, following it in the bending and / or elastic return movement, until the shape is squared and restored to its theoretical geometry.

[0104]

[0087] According to one embodiment of the method in question, the stirrup 2 is supported by the axial supports 60 until it is picked up by special gathering means which, in this configuration, are able to intercept the stirrup itself, in order to grasp it in a reliable and repetitive manner as required by automatic means.

[0105]

[0088] By manufacturing the stirrups using a shaping machine configured to bend both the head and tail metal elements, it is possible to complete the process after cutting the metal element 20. After performing part of the head bends, the stirrup being formed in this case remains resting on the axial supports 60, fed as necessary to perform the remaining bends, and in the appropriate step, it is gripped and moved by the second drawing assembly 31 , while in the appropriate step, the cutting means 5 and the bending assembly 40 perform the tail bends (figure 6).

[0106]

[0089] In practice, the stirrup being formed is gripped by the gripping means at the end of the bending steps when it has already been cut, held in place and gripped by the second drawing assembly 31 , thus avoiding the whip blow resulting from the cutting step.

[0107]

[0090] It should be noted that in order to perform the tail bends, after the raw material has been cut, the second drawing assembly 31 and the bending assembly 40 must be moved to a position further out than the bending plane 11 to allow the workpiece to pass the cutting means 5 as it moves back to perform the tail bends.

[0108]

[0091] At the end of the formation of the stirrup 2, the transversely movable supports 61 are activated, which are suitable to slide along the respective guides 62 made on the bending plane 11. In this step, the transversely movable supports 61 support the upper side 22 of the stirrup being formed, restoring the correct geometry and position of the stirrup 2 if this side 22 is deformed due to its own weight (figures 7 and 8).

[0109]

[0092] In this configuration, appropriate automatic gripping means are able to intercept the sides of the stirrup 2 in order to grasp it. If, on the other hand, automatic gripping means are not used, the transversely movable supports 61 are able to accompany the stirrup 2 to the appropriate unloading position, sliding along the guides 62 (figure 9).

[0110]

[0093] Any deformation of the lower side 21 of the stirrup 2, no longer supported by the axial supports 60, can be compensated by bringing the same lower side 21 to abut against an abutment member 63 arranged longitudinally in the lower part of the bending plane 11 (figure 10). The abutment member 63 is, for example, tiltable between a folded-down disengagement position, coplanar with the bending plane 11 , and a protruding position rotated by approximately 90° with respect to the bending plane 11.

[0111]

[0094] The stirrup 2 thus formed remains resting on the abutment member 63 in an aligned configuration in the unloaded position, waiting to be picked up, also in this case by means of special gripping means, in particular automatic gripping means, or by an operator (figure 11 ). In particular, if the stirrup 2 is picked up by automatic gripping means, it should also be supported by the transversely movable supports 61 to ensure that its geometry is precise.

[0112]

[0095] It should be noted that when all the bends are made on one side, as is the case with conventional stirrup bending machines that do not have a second drawing assembly, most international technical standards, including European standards, require the closing hooks 23 of the stirrup to be bent back at 135°. In this case, once the bends have been completed and before cutting, the stirrup to be gripped would be oriented at approximately 45° and, moreover, in a non-flat area of the machine (figure 12), which would make it difficult to grip the stirrup by automatic gripping means.

[0113]

[0096] According to another advantageous aspect of the invention, in this case it is possible to make a further bend at the last closing hook 23. This means that, following this additional bend, a further straight section 24 is formed, which serves exclusively to straighten the stirrup 2, by appropriately moving the stirrup backwards by means of the first drawing assembly 3 located upstream of the bending means (figure 14). This additional straight section 24 can be reduced as desired, up to complete elimination, since it would represent a minimal amount of wasted material.

[0114]

[0097] In particular, by performing a further 45° bend on the closing hook, the stirrup 2 is brought back with its sides substantially horizontal and vertical in the position suitable for gripping, with the lower side parallel and substantially coinciding with the feed direction of the metal element 20. Figure 15 shows a stirrup 2 made in accordance with the above mentioned method.

[0115]

[0098] The method and apparatus of the present invention therefore achieve the objective of optimally manufacturing stirrups, in particular large ones, for reinforcing building structures.

[0116]

[0099] In particular, the method and apparatus for producing stirrups according to the present invention make it possible to prevent deformation and / or restore the correct geometry of the sides of the stirrups during processing.

[0117]

[0100] The aforementioned purposes are achieved thanks to the inventive idea of supporting one or more sides of the stirrup being formed by means of supports that can be activated in a suitable step relatonship with the steps of forming the stirrup itself.

[0118]

[0101] The method and apparatus in question are therefore capable of allowing maximum production speed, avoiding undesirable permanent deformations that the stirrup could undergo as a result of excessive speed of execution. In particular, the solution described allows the theoretical geometry of the stirrup being processed to be restored once the formation of the stirrup itself has substantially reached completion.

[0119]

[0102] According to a prerogative of the present invention, the method and apparatus in question allow the stirrup produced to be accompanied in the most ergonomic and safe collecting position, away from moving members even when the machine is in operation.

[0120]

[0103] Another advantageous aspect of the invention is that it allows for a substantial reduction in the operating cycle time.

[0121]

[0104] The machine described as an example is subject to numerous modifications and variations depending on different requirements.

[0122]

[0105] For example, it is possible to provide that the transversely movable supports 61 actively and dynamically intervene during the bending steps of some sides to limit or dampen the movement of some parts of the stirrup, coming into contact in a differentiated manner for each of the transversely movable supports 61 and therefore also in a non-reciprocally aligned manner.

[0123]

[0106] In the practical implementation of the invention, the materials used, as well as the shape and dimensions, can be any depending on requirements.

[0124]

[0107] Where the technical features 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 by these reference signs.

Claims

Claims1. A method for manufacturing stirrups, in particular large stirrups, from elongated metal elements, such as metal profiles and rods in bars or rolls, comprising the steps of: a. feeding a said metal element (20) along a feed direction (A) defined above a bending plane (11 ); b. performing one or more successive bends on said metal element (20) on said bending plane (11 ); c. upon reaching a predetermined number of bends, cutting the stirrup (2) thus formed from the metal element (20) fed along the feed direction (A); d. in a suitable step relationship, activate support means (6) capable of engaging and supporting at least one side (21 , 22) of said stirrup (2) in formation, said step providing for d1. in a suitable step relationship, activating first transversally movable support means (61 ) suitable for being actuated with alternating motion in a direction transverse to the feed direction (A) of the metal element (20) on the bending plane (11 ).

2. The method of claim 1 , wherein said step of engaging and supporting at least one side (21 , 22) of said stirrup (2) in formation involves activating support means (6) movable between a first deactivation position retracted below said bending plane (11), so as not to interfere with the bending steps of said metal element (20), and a second activation position protruding from the same bending plane (11).

3. The method of claim 1 or 2, wherein said first support means (61) movable transversely comprise one or more support members capable of being actuated with alternating motion in a direction transverse to the feed direction (A) of the metal element (20) to support an upper side (22) of the stirrup in formation.

4. The method of any one of the preceding claims, wherein it provides for actuating said first transversely movable support means (61 ) on the bending plane (11) between an upper position in which they are adapted to engage and support an upper side (22) of the stirrup being formed and a lower position for transferring the stirrup to an unloading station.

5. The method of any one of the preceding claims, wherein said step of engaging and supporting at least one side (21) of the said stirrup (2) being formed comprises activating axial support means (60) arranged in alignment along the feed direction (A) of the metal element (20).

6. The method of any one of the preceding claims, wherein it comprises the further step of e. in a suitable step relationship, gripping said stirrup (2) by means of automatic gripping means to unload said stirrup (2) from said bending plane (11 ).

7. The method of any one of the preceding claims, wherein, in order to perform tail bends on said metal element (20), after cutting said metal element (20), it provides the further step off. bringing the bending means (40) and the drawing means (31 ) arranged downstream of said bending means (40) to a position more external than said bending plane (11 ), to allow the workpiece to pass the cutting means (5) in the backward movement of the workpiece itself.

8. The method of any one of the preceding claims, wherein it comprises the further step of g. after completing the last section of the final closing hook, making a further bend of appropriate size.

9. The method of claim 8, wherein the further bend is made at 45° if the closing hooks are made at 135°.

10. The method of any one of the preceding claims, wherein it comprises the additional step of h. moving the stirrup being worked by actuating a first drawing assembly arranged upstream of the bending means, also reversing its direction if necessary, until the desired length of the additional section is reached.

11. An apparatus for making stirrups, in particular large stirrups, from elongated metal elements, such as metal profiles and rods, comprising means (3) for feeding a said metal element (20) along a feed direction (A) defined above a bending plane (11 ) configured by a frame (10) of the same apparatus; bending means (4) for making on said metal element (20) one or more successive bends developed on said bending plane (11); cutting means (5) for cutting the stirrup (2) thus formed from said metal element (20) fed along said feed direction (A), upon reaching a predetermined number of bends; supporting means (6) suitable for being activated in a suitable step relationship with the formation of said stirrup (2) by said bending means (4) to engage and support at least one side (21 , 22) of said stirrup (2) in formation characterized in that said support means (6) comprise first support means (61 ) movable transversely and capable of being actuated with controlled motion in a direction transverse to said feeding direction (A) of the metal element (20) on said bending plane (11).

12. The apparatus of claim 11 , wherein said support means (6) are movable between a first deactivated position retracted below said bending plane (11 ), so as not to interfere with the bending steps of said metal element (20), and a second activated position protruding from the same bending plane (11).

13. The apparatus of claim 11 or 12, wherein said first transversely movable support means (61 ) are adapted to be actuated on said bending plane (11 ) between an upper position in which they are adapted to engage and support an upper side (22) of said stirrup (2) under formation and a lower transfer position of said stirrup (2) to an unloading station.

14. The apparatus of claim 11 or 12, wherein said support means (6) comprise second axial support means (60) arranged in alignment along said feed direction (A) of said metal element (20).

15. The apparatus of claim 11 , wherein it comprises a control unit (7) for automatically managing the various operating steps.

16. A metal stirrup, in particular of large dimensions, intended for use in the building industry, characterized in that it comprises at least one closing hook (23) obtained by bending a final section of the end side of the stirrup itself and having at the end a further bend defining a further straight section (24) configured to bring, at the end of the process, the sides of said stirrup (2) oriented horizontally and vertically.

17. The metal stirrup of claim 16, wherein said further straight section (24) is inclined at 45° with respect to the axis of said closing hook (23).

Images