Method and apparatus for manufacturing pre-cages for reinforcement

Abstract

The method for making pre-cages intended for forming cages for reinforcing building structures involves providing joining means (20) of one or more longitudinal auxiliary wires (3) at a joining plane to a plurality of stirrups (2) and arranging said joining means (20) in a non-interfering position, to leave a defined free space at said joining plane for the substantially frontal insertion of said stirrups. Individual stirrups (2) of said plurality of stirrups are then fed in orderly succession onto said joining plane in a direction of frontal insertion onto the same joining plane, and said joining means (20) are placed in a working position. Externally to said stirrups (2) fed onto said joining plane, said one or more longitudinal auxiliary wires (3) are joined and said one or more longitudinal auxiliary wires (3) integral with the stirrups (2) already joined are advanced step-by-step. The operating cycle is repeated until a pre-cage (1) is obtained, presenting all the stirrups (2) of said plurality of stirrups (2) spaced exactly at the same steps as those provided for the cage to be produced.

Description

[0001] Description

[0002] METHOD AND APPARATUS FOR MANUFACTURING PRE-CAGES FOR REINFORCEMENT Technical field

[0003]

[0001] The present invention relates to a method and apparatus for manufacturing pre-cages intended for the formation of cages for reinforcing building structures.

[0004] Prior art

[0005]

[0002] The use of metal cages for the reinforcement of reinforced concrete pillars and beams is currently well known in the construction industry. These metal cages usually consist of longitudinal bars connected by appropriately spaced transverse stirrups. The stirrups generally define a closed path, for example in the shape of a quadrilateral, with the ends folded and overlapped to form closing hooks. The longitudinal bars are inserted inside the profile defined by the stirrups, for example at the corners of this profile.

[0006]

[0003] The traditional method of making these metal cages involves manually connecting the appropriately spaced stirrups to the longitudinal bars. However, this solution requires a lot of time and results in high labor costs. To overcome these drawbacks, the use of semiautomatic machines has been proposed, which simplify the formation of reinforcement cages by passing through an intermediate step consisting of the formation of a pre-cage. However, the formation of a pre-cage introduces a new problem, namely the protection of the final product against corrosion.

[0007]

[0004] More recently, in order to automate the formation of cages for reinforcing building structures, it has been proposed to first create pre-cages that facilitate the subsequent completion of the reinforcement cages. These pre-cages are essentially formed by a truss consisting of a plurality of closed or open profile stirrups arranged on appropriately spaced parallel planes, connected by at least one pair of thin disposable auxiliary wires, essentially with a cross-section smaller than the cross-section of the stirrups' rods, not provided for by the designers. The auxiliary wires are usually welded on the sides outside the stirrups, according to a predetermined step. Since the auxiliary wires are external, it is possible to easily insert the stirrups between them, progressively forming the aforementioned truss. The movement of inserting the stirrups, first transversely to the auxiliary wires and then parallel to insert the stirrups between the electrodes, is unnatural for the operator, who also finds himself working in an unbalanced and non-ergonomic position. However, this results in an intermediate or pre-cage structure in which the stirrups are fixed to each other on the sides with the auxiliary wires at the required distance from each other.

[0008]

[0005] To form the reinforcement cages, the process is then completed and secured by attaching the appropriate longitudinal bars to the truss, inserted inside the stirrup and joined to at least part of them, in the positions specified in the design. Thanks to the fact that the pre- cage is sufficiently rigid and stable in itself, particularly for the transport and handling of the corresponding finished cage, it is not necessary for the longitudinal bars to be fixed at all intersections with the stirrups in order to obtain a stable structure, but it is sufficient to make a very small number of bindings, sufficient to hold the bars in position.

[0009]

[0006] It should be noted that the pre-cage itself, being welded, is capable of providing sufficient rigidity and stability to the entire structure.

[0010]

[0007] Patent documents EP 0 667 195 and EP 1 378 302 in the name of the same Applicant describe a method and a machine for making pre-cages of the type mentioned.

[0011]

[0008] These known machines, being semi-automatic, require the use of at least one operator, who, as mentioned, is forced to work in an uncomfortable position for the entire time, and a second operator to manage the inlet and outlet material, in order to limit production downtime and maintain a sufficient level of production.

[0012]

[0009] The known machines are equipped with a drawing head for the pre-cage being formed, which ensures optimal straight development of the pre-cage. However, in addition to being expensive, this has the disadvantage of having to release the cage and return the drawing head only after the machine has been freed from the newly completed product, and then prepare the machine for the formation of the next pre-cage.

[0013]

[0010] To overcome these drawbacks, a different type of machine is available that pushes the auxiliary wires forward to the welding points. However, this type of machine does not guarantee the straight development of the pre-cage, which creates significant problems, especially in the case of long cages. The deviation of the pre-cage from the correct straight development is essentially due to the fact that the auxiliary wires undergo a change in length as a result of the high temperature during welding. Added to this is the fact that if one of the auxiliary wires is positioned at an overlap, the temperature reached is much higher, which worsens the situation described above.

[0014]

[0011] For these and other reasons, the productivity of the semi-automatic machines mentioned above is modest and limited in terms of the types of pre-cages that can be produced.

[0015]

[0012] It has been observed that at the aforementioned disposable auxiliary wires, the distance between the wires themselves and the surface of the casting is less than the distance of the stirrup, thus reducing the so-called concrete cover. Between one stirrup and another, the auxiliary wires can be suitably shaped with loops to fit more closely to the external surface of the concrete; however, at the stirrup, the auxiliary wires, even if partially crushed by the welding, always reduce the amount of concrete cover, even if only locally. This results in less protection against corrosion of the steel constituting the reinforcement. At these points, which are less protected by reduced concrete cover than is the case for the stirrups, actual gaps can open up to corrosion, which thus reaches the rest of the reinforcement, reducing the overall durability of the entire structure. Disclosure

[0016]

[0013] The purpose of this invention is to solve the aforementioned problems by devising a method and an automatic apparatus that allow for the optimal creation of pre-cages intended for the formation of cages for the reinforcement of building structures.

[0017]

[0014] Within the scope of this task, a further purpose of the present invention is to provide a method and apparatus for the production of pre-cages equipped with disposable auxiliary wires arranged in any area of the outer perimeter of the stirrups, where in particular their presence does not compromise the concrete cover.

[0018]

[0015] Another purpose of the present invention is to provide a method and apparatus for manufacturing pre-cages that can be used with any stirrup geometry.

[0019]

[0016] Another purpose of the present invention is to provide a method and automatic and / or manual apparatus for making pre-cages equipped with disposable auxiliary wires capable of ensuring high productivity with limited labor requirements.

[0020]

[0017] Another purpose of the present invention is to provide a method and apparatus with automatic stirrup feeding and capable of operating with manual stirrup feeding for the production of pre-cages equipped with disposable auxiliary wires.

[0021]

[0018] Another purpose of the present invention is to provide a method and automatic and / or manual apparatus that allows for easier insertion of the stirrups compared to known machines for the production of pre-cages equipped with disposable auxiliary wires.

[0022]

[0019] Another purpose of the present invention is to provide a method and apparatus for making pre-cages equipped with disposable auxiliary wires that do not compromise corrosion resistance.

[0023]

[0020] Another purpose of the present invention is to provide a method and apparatus for making pre-cages that allow the next production cycle to be restarted immediately, without requiring unloading and repositioning of the handling members of the pre-cage being formed.

[0024]

[0021] A further purpose of the present invention is to provide a method and apparatus that allow the formation of pre-cages equipped with disposable auxiliary wires on a support bench that is at least partially devoid of drive members for the pre-cage being formed.

[0025]

[0022] Another purpose of the present invention is to provide an apparatus for the production of pre-cages for reinforcement that is simple in design and function, safe and reliable in use, and relatively inexpensive.

[0026]

[0023] The aforementioned purposes are achieved, according to the present invention, by the method for manufacturing pre-cages intended for the formation of cages for the reinforcement of building structures according to claim 1 .

[0027]

[0024] The method for manufacturing pre-cages intended for the formation of cages for reinforcing building structures comprises the following steps: a. providing means for joining one or more external longitudinal auxiliary wires at a joining plane to a plurality of closed or open profile stirrups, configured for the formation of a cage for reinforcing building structures; b. arranging said joining means in a position that does not interfere with a free space defined at said joining plane for the substantially frontal insertion of said stirrups; c. feeding a first stirrup of said plurality of stirrups onto said joining plane in a direction of frontal or substantially frontal insertion onto the same joining plane; d. arranging said joining means in a working position; e. externally joining said one or more longitudinal auxiliary wires to said first stirrup fed onto said joining plane; f. advancing step-by-step said one or more longitudinal auxiliary wires integral with said first stirrup already joined.

[0028]

[0025] The method involves repeating the previous cycle, from point a. to point f., inserting a subsequent stirrup in an ordered sequence until a pre-cage is obtained having all the stirrups of said plurality of stirrups spaced exactly at the same steps as those provided for the cage to be produced.

[0029]

[0026] Advantageously, the method comprises the additional step of h. at the end of the formation of said pre-cage, cutting by means of cutting means associated with said drawing means said longitudinal auxiliary wires downstream of said joining plane.

[0030]

[0027] Advantageously, said step of e. joining externally to said first stirrup fed onto said joining plane said one or more longitudinal auxiliary wires, provides for joining externally to said first stirrup at least one auxiliary wire fixed at a corner of the same stirrup.

[0031]

[0028] Preferably, the method provides for externally joining said one or more longitudinal auxiliary wires to said first stirrup by welding.

[0032]

[0029] According to one aspect of the present invention, said step of c. feeding a first stirrup of said plurality of stirrups onto said joining plane involves inserting said stirrup in a rectilinear or substantially rectilinear motion, substantially parallel to said work surface and orthogonal to said joining plane, at the rear of the pre-cage being formed.

[0033]

[0030] Advantageously, said step of d. arranging said joining means in a working position involves, in succession, d1. moving said stirrup backward to bring it into abutment with reference means associated with said joining means; d2. bringing the welding members of said joining means closer together so as to clamp said stirrup and said longitudinal wire between them.

[0031] Preferably, said reference means associated with said joining means consist of support means configured to carry the internal welding members of said joining means in a movable manner.

[0034]

[0032] Advantageously, the method involves moving said welding members of said joining means away from each other to release said stirrups and said longitudinal wires following said mutual welding step.

[0035]

[0033] Advantageously, the method involves inserting said stirrup to a position advanced with respect to said joining means, arranging said joining means in said working position, and retracting said stirrup to bring it into abutment with said joining means at said joining plane, before tightening and joining said stirrup to said one or more longitudinal auxiliary wires.

[0036]

[0034] The pre-cage intended for the formation of cages for the reinforcement of building structures, according to the present invention, comprises a plurality of closed or open profile stirrups arranged on suitably spaced parallel planes; one or more thin longitudinal auxiliary wires, fixed externally to said stirrups at at least one corner of the stirrups themselves.

[0037]

[0035] Preferably, there are three or four such longitudinal auxiliary wires.

[0038]

[0036] Advantageously, one of said longitudinal auxiliary wires is arranged at the overlap of the sides of the closing hook of said stirrup. In this way, the two flaps are both welded by said disposable auxiliary wire and the stirrup thus becomes a closed profile with greater rigidity.

[0039]

[0037] It should be noted that, in order to comply with good manufacturing practices in the sector, the closing hooks of the stirrup must not all be arranged on the same side in order to avoid the so-called "hinge effect."

[0040]

[0038] Advantageously, one or more longitudinal auxiliary wires may have a loop at the points where they are coupled with said stirrups. In this way, the section of said auxiliary wires comprising one between one stirrup and another remains further inside the concrete structure.

[0041]

[0039] Preferably, said loop has a trapezoidal or curved shape.

[0042]

[0040] The present invention also concerns apparatus for the production of pre-cages intended for the formation of cages for the reinforcement of building structures, as described above.

[0043]

[0041] The apparatus for making pre-cages intended for the formation of cages for reinforcing building structures comprises means for joining said one or more longitudinal auxiliary wires externally to said stirrups, at a joining plane with a plurality of stirrups, said joining plane being configured to receive in orderly succession individual stirrups of said plurality of stirrups in a direction of insertion frontal or substantially frontal to the same joining plane; means for drawing the pre-cage in formation, movable step-by-step between a gripping position, located downstream of said joining plane, and a release position; cutting means associated with said drawing means for cutting said longitudinal auxiliary wires downstream of said joining plane.

[0044]

[0042] Advantageously, said cutting means are arranged downstream of said drawing means so that said auxiliary wires remain in gripping even after cutting.

[0045]

[0043] In this way, said auxiliary wires are arranged for the creation of the next pre-cage.

[0046]

[0044] Advantageously, said joining means comprise one or more adjustable welding heads to be arranged in a position substantially orthogonal to the curvature of said stirrup at the point of contact with the auxiliary wire to be welded.

[0047]

[0045] Preferably, said welding heads comprise, respectively, an external welding member and an internal welding member to the stirrup to be welded.

[0048]

[0046] According to one aspect of the present invention, said internal welding member is retractable to position said joining means in said non-interfering position.

[0049]

[0047] Preferably, said internal welding members are cylindrical in shape.

[0050]

[0048] Preferably, said welding heads are adjustable on the vertical plane of the stirrup.

[0051]

[0049] Preferably, said welding heads are adjustable by rotating substantially around the axis of a relative auxiliary wire.

[0052]

[0050] Preferably, said welding heads are adjustable by rotating substantially around the axis of said internal welding member.

[0053]

[0051] Preferably, said welding heads are configured to rotate substantially around the axis of a respective auxiliary wire.

[0054]

[0052] Preferably, said welding heads are adjustable on the vertical plane of the stirrup in orthogonal directions.

[0055]

[0053] Preferably, said orthogonal adjusting directions of the welding heads are horizontal and vertical, respectively.

[0056]

[0054] Preferably, the apparatus comprises a frame defining a work surface that extends longitudinally in front of said joining plane, carrying said means for joining the longitudinal auxiliary wires externally to said stirrups.

[0057]

[0055] Preferably, said cutting means are arranged downstream of said drawing means in the direction of formation of the pre-cage.

[0058]

[0056] Preferably, the apparatus comprises an extractor member inserted in a concealed manner within an opening made longitudinally to said work surface and designed to be operated with an alternating motion between an active stroke in a position emerging from said opening, in the direction of formation of the pre-cage, and a return stroke in which the same extractor member is arranged to be concealed inside said opening.

[0059] Brief description of the drawings

[0057] The details of the invention will be more evident from the detailed description of a preferred embodiment of the apparatus for making pre-cages intended for the formation of cages for the reinforcement of building structures, illustrated by way of example in the attached drawings, in which:

[0060] Figure 1 shows a perspective overview of the apparatus for making pre-cages according to the present invention;

[0061] Figure 2 shows a detailed perspective view of the operating members of the apparatus; Figures 3, 4, and 5 show, respectively, a front view of the apparatus illustrating different steps of adjusting the means for joining the said auxiliary wires;

[0062] Figures 6 to 10 show, respectively, a similar front view of the apparatus in different steps of joining the said auxiliary wires;

[0063] Figures 6a to 10a show an enlarged portion of Figures 6 to 10;

[0064] Figures 8b and 8c show, respectively, a perspective view of the portion of the apparatus illustrated in Figure 8a in different operating steps;

[0065] Figures 11 to 14 show, respectively, a perspective view of means for cutting said auxiliary wires;

[0066] Figures 15 and 16 show, respectively, a perspective view of the apparatus in question during the extraction step of the pre-cage produced;

[0067] Figures 15a, 15b, and 15c show, respectively, an enlarged detail of Figure 15 in different operating positions of the means for extracting the pre-cage produced;

[0068] Figures 17 to 38 show, by means of a perspective view of a portion of the apparatus, the sequence of operating steps for the creation of a pre-cage according to the method that is the subject of this invention.

[0069] Description of embodiments of the invention

[0070]

[0058] With particular reference to these figures, 1 indicates a pre-cage intended for the formation of cages for the reinforcement of building structures. The pre-cage 1 comprises a plurality of closed or open profile stirrups 2, arranged on appropriately spaced parallel planes; the stirrups 2 are connected to each other by one or more longitudinal auxiliary wires 3, preferably of thin thickness.

[0071]

[0059] Preferably, there should be three or four longitudinal auxiliary wires.

[0072]

[0060] The stirrups 2, technically defined as "transverse reinforcement" in the specific field of construction, are made in a known manner from elongated metal elements, such as profiles and steel rods for reinforced concrete, hereinafter also referred to as rods for simplicity.

[0073]

[0061] Advantageously, the pre-cage in question provides that at least one of said one or more longitudinal auxiliary wires 3 is fixed externally to said stirrup 2 at an external corner of the stirrup 2, as illustrated in patent application PCT / IT2025 / 050152 in the name of the same Applicant, which is hereby referred to in its entirety.

[0074]

[0062] More specifically, said one or more longitudinal auxiliary wires 3 are inserted and fixed by means of special welding members, at the dead angle defined externally to the stirrup 2, understood as the difference between the actual and ideal dimensions, which creates a space in which to house the auxiliary wire 3 without eroding the thickness of the concrete cover measured on the ideal dimensions.

[0075]

[0063] The apparatus for the production of the aforementioned pre-cages intended for the formation of cages for the reinforcement of building structures is indicated with 10. The apparatus 10 is preferably connected to a robotic assembly configured to pick up the stirrups 2 from the stirrup machine and feed them in an ordered sequence onto a joining plane defined by the apparatus itself. The joining plane is preferably arranged on a vertical plane transverse to the longitudinal axis of the pre-cage being formed. In particular, as specified below, the stirrups 2 are fed by the said robotic assembly onto the joining plane in a direction of insertion that is frontal or substantially frontal to the joining plane itself.

[0076]

[0064] The apparatus 10 comprises a frame 11 that defines a work surface 12 that extends longitudinally starting substantially from said joining plane. Usefully, the work surface 12 extends longitudinally with a bench 13 designed to support the pre-cage being formed starting from the front, as specified below.

[0077]

[0065] At the joining plane, the apparatus comprises means 20 for joining the stirrup 2 to one or more longitudinal auxiliary wires 3, previously arranged at the same joining plane in the most suitable positions chosen for the pre-cage. The longitudinal auxiliary wires 3 are fed to the joining plane preferably by means of respective straightening members 4.

[0078]

[0066] The joining means 20 are preferably welding means, for example of the resistance type, also known as welding heads. In particular, the joining means 20 provide one or more welding members 21 operating in the joining positions of the stirrups 2 to said one or more longitudinal auxiliary wires 3.

[0079]

[0067] According to a feature of the invention, the welding members 21 are movable, substantially at said joining plane, between a position of non-interfering with the free insertion space for the stirrups 2 and a working position in which the individual stirrups 2 are welded to said one or more longitudinal auxiliary wires 3 (see Figures 6 to 10 and the related enlarged portions in Figures 6a to 10a).

[0080]

[0068] In particular, said welding members 21 comprise, respectively, an external welding member 22 and an internal welding member 23 with respect to the stirrup 2 to be welded. According to the present invention, both welding members 22, 23 or at least the internal welding member 23 are movable to position themselves in said non-interfering position.

[0081]

[0069] More precisely, Figures 6 to 10 and the related enlarged portions 6a to 10a show the sequence of movement of the electrodes, starting from the initial position in which the internal welding member 23 is placed outside the stirrup 2 (Figures 6 and 6a). The internal welding member 23 is then inserted inside the projection of the perimeter of stirrup 2 along a trajectory that avoids interference with the auxiliary wire 3 located in the corner (figures 7 and 7a) and then moved to the point of internal tangency with the curvature of the stirrup 2 in the corner and aligned with the same auxiliary wire 3 (figures 8 and 8a).

[0082]

[0070] It should be noted that before the next step, the stirrup 2, which was in a more advanced position than the welding members, so as not to interfere with them , is preferably moved back by the same gripping means, in order to be placed against the welding plane, to ensure the orthogonality of the stirrup with respect to the axis of the pre-cage being formed (figures 8b and 8c). Less advantageously, the welding members could, of course, be advanced relative to the stirrup.

[0083]

[0071] The reciprocal movement of the welding members is then activated, clamping the stirrup 2 and the auxiliary wire 3 to weld them, either in rapid succession or simultaneously (figures 9 and 10).

[0084]

[0072] Along the work surface, the drawing means 30 of the pre-cage in formation are alternately movable. In particular, these drawing means 30 are movable in step-by-step motion between a retracted position for gripping the pre-cage, located downstream of the aforementioned joining plane, according to the direction of advance of the pre-cage in formation, and an advanced release position. Between the gripping and release positions, the drawing means 30 advance at a step equal to the distance between one stirrup and another as specified in the design.

[0085]

[0073] In the case illustrated, the drawing means 30 comprise one or more pincer members 31 designed to grip each longitudinal auxiliary wire 3 in a section free from the stirrups 2. Obviously, it is possible to use different types of drawing means or to position them differently.

[0086]

[0074] Preferably, the pincer drawing has a stroke that allows it to make several step-by-step movements and therefore only perform the return stroke when it is unable to take a further step.

[0087]

[0075] It should be noted that the pre-cage must always be in gripping to ensure the accuracy of the advances and therefore, when the drawing by means of the pincer members 31 has exhausted its useful stroke, the welding members 21 on the newly joined stirrup 2 remain closed to hold the pre-cage in position and thus allow the pincer members 31 to release the pre-cage and perform the return stroke to re-engage the auxiliary wires 3 in a more rearward position.

[0088]

[0076] Advantageously, cutting means 40 for the longitudinal auxiliary wires 3 are associated with the drawing means 30 at the end of the pre-cage formation (see Figures 11 to 14). These cutting means comprises respective shears 41 configured to cut said longitudinal auxiliary wires 3 upstream of the last fixed stirrup. The shears 41 are arranged downstream of respective pincer members 31 so as to maintain the auxiliary wires 3 in grip even after cutting and also during the adjusting and positioning operations of the joining members 20 in order to prepare for the formation of pre-cages of different geometries.

[0089]

[0077] It should be noted that, in the illustrated embodiment, the pincer members 31 and the shears 41 form a single compact assembly in order to cut the shortest possible tail and head portions and to reduce the number of mechanical components. Obviously, it is possible to provide that the pincer members 31 and the shears 41 are made separately and operate independently.

[0090]

[0078] Preferably, the apparatus comprises an extractor member 50 inserted in a concealed manner within an opening 14 made longitudinally along a longitudinal axis of the bench 13 (see Figures 15 and 16). The extractor member 50 is designed to be operated with alternating motion along said opening 14, between an active stroke in a position emerging from the opening 14, in the direction of pre-cage formation, and a return stroke in which the extractor member 50 is arranged inside the opening 14.

[0091]

[0079] Advantageously, according to the present invention, the auxiliary wires 3 can be welded at least at one corner on the outside of the stirrup 2. To this end, the welding heads 21 can be suitably oriented to be positioned substantially perpendicular to the curvature of the stirrup 2 at the point of contact with the auxiliary wire 3. In particular, the welding heads 21 can be oriented on the vertical plane of the stirrup 2 and adjusted in orthogonal directions, in particular horizontally and vertically (Figures 3 and 4), as well as oriented by rotating substantially around the axis of a relative auxiliary wire 3 (Figure 5).

[0092]

[0080] The method for making pre-cages intended for the formation of cages for the reinforcement of building structures, using the apparatus described, is easily understood from the following description.

[0093]

[0081] First, at least the electrodes inside the stirrup 2 are positioned at the non-interfering position. At the same time, the straightening members and the auxiliary wires 3 contained therein are moved to a non-interfering position. This creates a free space for the insertion of the stirrup 2, either manually or, preferably, automatically by means of a special robotic assembly (figure 17).

[0094]

[0082] It should be noted that the individual stirrups 2 are inserted in a substantially straight motion parallel to the work surface of the machine and orthogonal to the joining plane, at the rear of the pre-cage being formed. In particular, the insertion motion of the stirrups 2 extends until it reaches just beyond the length of the electrodes.

[0095]

[0083] In this way, a first stirrup 2 is inserted into the aforementioned free space. The electrodes are then moved into the working position so that the joining plane of the stirrup 2 with the auxiliary wires 3 can be identified by means of the relative supports (Figures 18 and 19). At the same time, the straighteners and auxiliary wires 3, preferably integral with them, are also placed in the working position.

[0096]

[0084] The first stirrup 2 is then moved back sufficiently to bring it into contact with the supports of the internal electrodes, i.e., on the joining plane and perfectly perpendicular to the direction of development of the pre-cage to be formed (figure 20).

[0097]

[0085] At this point, the electrodes outside the stirrup 2 clamp onto the internal electrodes, gripping the stirrup 2 inserted between the electrodes themselves (figure 21 ). The auxiliary wires 3 are then joined to the same stirrup 2, preferably by welding (figure 22).

[0098]

[0086] When the electrodes of the joining means reopen, the first stirrup 2 is permanently attached to the auxiliary wires 3 (figure 23). The pincer members 31 of the drawing means already gripping the auxiliary wires 3 advance one step, dragging the auxiliary wires 3 and with them the first stirrup 2 now joined (Figure 24). The electrodes are then disengaged and retracted (Figures 25 and 26) and the straightening members are retracted (Figure 27).

[0099]

[0087] The operating cycle described is repeated identically for the stirrups 2 inserted sequentially on the joining plane (figure 28), until the pincer members 31 no longer have sufficient travel to perform the next step-by-step movement (figures 29-33).

[0100]

[0088] At this point, the electrodes outside the stirrup 2 clamp onto the internal electrodes, locking the last stirrup fixed to the relative auxiliary wire between the electrodes (figure 34). In the appropriate step relationship, the pincer members 31 open, moving into a noninterfering position (figure 35).

[0101]

[0089] The pincer members of the drawing means are preferably retracted to the rearmost position between the last stirrup 2 fixed and the next one. The drawing pincers are tightened again on their respective auxiliary wires 3.

[0102]

[0090] It should be noted that from this point onwards, the portion of the pre-cage located downstream of the drawing pincer members is pushed without undergoing unwanted deformations that would deviate from its straightness; the welds are now sufficiently cool and the portion of the pre-cage upstream of the pincer members is pulled as usual, so as to keep that section of the pre-cage straight while the welds are still hot and deformable.

[0103]

[0091] Subsequently, the electrodes reopen and the drawing means bring the pre-cage into formation in the forward position for the next step.

[0104]

[0092] The operating cycle described above is repeated identically from the beginning until the pre-cage is completed.

[0105]

[0093] After joining the last stirrup 2, the now completed pre-cage is positioned, moving forward or backward, at the desired height for cutting the auxiliary wires 3 to the desired length (figure 36). The welding electrodes are clamped onto the auxiliary wires 3 to hold the pre- cage in place as described above, and the feed pincers and shears are retracted.

[0106]

[0094] The drawing pincers of the auxiliary wires 3 are tightened to keep the same auxiliary wires 3 ready in position for the formation of the next pre-cage. The shears, positioned downstream of the pincer members, cut the respective auxiliary wires 3, detaching the pre-cage from the raw material of the auxiliary wires 3 (figure 37).

[0107]

[0095] Next, the extractor member emerges from the support surface. The extractor member, now in the raised position, is advanced until it encounters a welded stirrup and pushes the entire pre-cage forward, creating space to start the production cycle of the next pre-cage (see Figures 15, 16, and 38 and the enlarged details in Figures 15a, 15b, and 15c).

[0108]

[0096] At the same time or in masked time, the extractor member is retracted and moved to a non-interfering position so that it is ready to extract the next pre-cage produced.

[0109]

[0097] Advantageously, the operational steps described above are managed by a control unit 100 associated with the apparatus.

[0110]

[0098] The method and apparatus of the present invention achieve the purpose of automatically manufacturing pre-cages intended for the formation of cages for the reinforcement of building structures.

[0111]

[0099] In particular, the method and apparatus in question allow the automatic production of precages equipped with disposable auxiliary wires arranged in any area of the outer perimeter of the stirrup.

[0112]

[0100] The aforementioned purpose is achieved thanks to the inventive idea of feeding the stirrups intended to form the pre-cage to a predetermined joining plane in an ordered sequence, either manually or preferably automatically by means of a special robotic assembly, according to a direction of insertion that is frontal or substantially frontal to the same joining plane.

[0113]

[0101] In particular, the individual stirrups are inserted preferally in a substantially straight motion parallel to the work surface of the machine and orthogonal to the joining plane, at the rear of the pre-cage being formed.

[0114]

[0102] According to an advantageous aspect of the invention, the joining means are carried entirely on board the apparatus and are equipped with mobile support means for at least the electrode inside the pre-cage, so as to disengage, thus freeing the stirrup insertion area to facilitate their introduction. In particular, in order to completely free up the insertion area of the stirrup, it is possible to move the auxiliary wire straightening members and the wires themselves, preferably together with the mobile support means for the electrode inside the pre-cage. In this way, upstream of the apparatus, a sort of passage tunnel is freed up, corresponding at least to the projection of the pre-cage itself in formation.

[0115]

[0103] It should be noted that, with reference to the arrangement of the electrode inside the precage in a non-interfering position, this also includes the possibility of moving the straightening members and any other members in a coordinated manner to prepare the apparatus for the passage and reception of stirrups by means of an automatic or manual gripping and handling system.

[0116]

[0104] This makes it easier to feed the stirrups into the apparatus from the front and not transversely as is the case with known machines, and to free up the space necessary for the stirrup and the appropriate automatic or manual gripping means to hold the stirrup in gripping until it is completely positioned and gripped by other members, such as the welding members themselves.

[0117]

[0105] During insertion, a special cycle is performed in which, once the stirrup has been inserted, the electrode inside the pre-cage is brought into an active position inside the stirrup and the stirrup itself is retracted to be inserted appropriately between the electrodes which, after being tightened, take over the stirrup so that the gripping means can open and go on to grip the next stirrup.

[0118]

[0106] Advantageously, the apparatus can be equipped with a hybrid system for step-by-step movement of the pre-cage of the "drawing and push" type. This system involves pulling the pre-cage, preferably with a pincer drawing, for a certain number of steps in the early stages of pre-cage formation and, once the welds have cooled sufficiently, pushing the section that is no longer plastically deformable, which thus remains straight for the rest of the work cycle without the need for a drawing trolley. In this way, it is possible to obtain the advantages of both the drawing and pushing systems, while avoiding their disadvantages.

[0119]

[0107] The handling method described involves an advantageous cycle with the return of the already formed pre-cage section for the execution of a minimum step, thus not constrained by the bulk of the gripping and welding means.

[0120]

[0108] Advantageously, before opening and resuming the pincer drawing, in order to avoid errors introduced by the expansion of the auxiliary wire, it is possible to perform a cycle of opening the welding electrodes and closing them after an appropriate time.

[0121]

[0109] In addition, each welding unit can be equipped with shears to cut each auxiliary wire. In this way, the auxiliary wires can also be detached from the coil automatically.

[0122]

[0110] Advantageously, the shears are shaped in such a way as to leave a protrusion of the auxiliary wire from the stirrup of the desired length or preferably as small as possible to make the pre-cage less dangerous in subsequent handling operations and to save raw material.

[0123]

[0111] According to another feature of the invention, the apparatus is equipped with an extractor which, once the auxiliary wires have been cut, is able to advance the finished pre-cage longitudinally, to free the apparatus and continue a new operating cycle without interruption. The finished pre-cage can thus be unloaded manually or by means of appropriate mechanical means.

[0124]

[0112] According to another advantageous aspect of the invention, the positioning movements of the welding heads also move the pincer drawing members, the drawing members, and the straightening members in a coordinated manner, so that all of these members can be adjusted with a single maneuver.

[0125]

[0113] In the practical implementation of the invention, the materials used, as well as the shape and dimensions, can be any depending on the requirements.

[0126]

[0114] 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 making pre-cages intended for forming cages for reinforcing building structures, comprising the steps of: a. providing joining means (20) for one or more longitudinal auxiliary wires (3) at a joining plane to a plurality of closed or open profile stirrups (2), configured for the formation of a cage for reinforcing building structures; b. arranging said joining means (20) in a non-interfering position to create a free space at said joining plane to allow the substantially frontal insertion of said stirrup; c. feeding a first stirrup (2) of said plurality of stirrups towards said joining plane in a direction of frontal or substantially frontal insertion at the same joining plane, said stirrup(2) being inserted in a substantially rectilinear motion, orthogonal to said joining plane, upstream of said pre-cage (1 ) under formation; d. arranging said joining means (20) in a working position; e. externally joining said one or more longitudinal auxiliary wires (3) to said first stirrup (2) fed onto said joining plane; f. advancing step-by-step said one or more longitudinal auxiliary wires (3) integral with said first stirrup (2) already joined; g. repeating the previous cycle, from point a. to point f., inserting in ordered sequence a subsequent stirrup (2) until obtaining a pre-cage (1) having all the stirrups (2) of said plurality of stirrups (2) spaced exactly with the same step provided for the cage to be produced.

2. The method of claim 1 , wherein said step of e. joining externally to said first stirrup (2) fed onto said joining plane said one or more longitudinal auxiliary wires (3), provides for joining externally to said first stirrup (2) at least one auxiliary wire (3) fixed at a corner of the same stirrup (2).

3. The method of claim 1 or 2, wherein it provides for externally joining said one or more longitudinal auxiliary wires (3) to said first stirrup (2) by welding.

4. The method of any one of the previous claims, wherein it comprises the further step of h. at the end of the formation of said pre-cage (1 ), cutting said longitudinal auxiliary wires(3) downstream of said joining plane by means of cutting means (40) associated with said drawing means (30).

5. The method of any one of the preceding claims, wherein it provides for inserting said stirrup (2) to a position advanced with respect to said joining means (20), for arranging said joining means in said working position and then for retracting said stirrup (2) to bring it into abutment with said joining means (20) at said joining plane, before tightening and joining said stirrup (2) to said one or more longitudinal auxiliary wires (3).

6. An apparatus for making pre-cages intended for forming cages for reinforcing building structures, of the type comprising a plurality of closed or open profile stirrups (2) arranged on suitably spaced parallel planes and mutually constrained by one or more longitudinal auxiliary wires (3), characterized in that it comprises joining means (20) configured to join said one or more longitudinal auxiliary wires (3) externally to said stirrups (2), at a joining plane to a plurality of stirrups (2), said joining plane being configured to receive in orderly succession individual stirrups (2) of said plurality of stirrups (2) according to a direction of insertion frontal or substantially frontal to the same joining plane, in use said stirrup (2) being inserted according to a substantially rectilinear motion, orthogonal to said joining plane, upstream of said pre-cage (1 ) in formation; drawing means (30) configured to draw said pre-cage (1 ) in formation, said drawing means (30) being movable step-by-step between a gripping position, located downstream of said joining plane, and a release position; cutting means (40) associated with said drawing means (30) configured to cut said longitudinal auxiliary wires (3) downstream of said joining plane.

7. The apparatus of claim 6, wherein said joining means (20) comprises one or more welding heads (21) that can be oriented on the vertical plane of said stirrup (2) to be positioned substantially perpendicular to the curvature of the stirrup (2) at the point of contact with the auxiliary wire (3) to be welded at a corner of the stirrup (2).

8. The apparatus of claim 7 or 8, wherein said welding heads (21 ) are adjustable by rotating substantially around the axis of a relative auxiliary wire (3).

9. The apparatus of claim 7 or 8, wherein said welding heads (21) are configured to rotate substantially around the axis of a respective auxiliary wire (3).

10. The apparatus of claim 7 or 8, wherein said welding heads (21) are configured to rotate pivoted substantially on the axis of an internal welding member (23) of the welding heads (21 ) themselves.

11. The apparatus of claim 7, wherein said welding heads (21) are adjustable in the vertical plane of the stirrup (2) in orthogonal directions.

12. The apparatus of claim 11 , wherein said orthogonal adjusting directions of the welding heads (21 ) are respectively horizontal and vertical.

13. The apparatus of any one of claims 6 to 12, wherein it comprises a frame (11 ) defining a work surface (12, 13) which extends longitudinally in front of said joining plane, bearing said means (20) for joining the longitudinal auxiliary wires (3) externally to said stirrups (2).

14. The apparatus of claim 6, wherein said cutting means (40) are arranged downstream of said drawing means (30) in the direction of formation of the pre-cage (1 ).

5. The apparatus of claim 6, wherein it comprises an extractor member concealed within an opening (14) made longitudinally to said work surface (13) and designed to be operated with alternating motion between an active stroke in a position emerging from said opening, in the direction of formation of the pre-cage (1 ), and a return stroke in which the same extractor member is concealed within said opening.

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