METHOD AND APPARATUS FOR MAKING STIRRUPS

Technical Field

The present invention concerns a method and an apparatus for making stirrups, in particular tridimensional stirrups.

Background Art

It has been known the use of apparatuses for making variously shaped metal stirrups starting from a metal rod. In particular, it has been known the requirement of making also tridimensional stirrups, intended, for example, to be used as spacing element suitable to be inserted between two metal nets. In order to accomplish this task, at present electro- welded lattice girders are also used, even though this solution proves to be expensive, considering that lattice girders are only available of standard sizes. The use of tridimensional stirrups, of suitable dimensions and therefore made to measure for every requirement, is vice versa cheaper and more practical.

A problem generally complained in this specific field lays in the difficulty of producing tridimensional stirrups. At present, folding apparatuses exist able to fold an iron rod for making bidimensional stirrups, while the making of tridimensional stirrups has not yet found efficacious solutions.

EP 0519865 discloses a tridimensional apparatus which allows to make stirrups of considerable size. Nevertheless, such solution does not well suit to the use in the field of metal rods for reinforced concrete, furthermore it results to be very complicated and expensive to produce.

EP 0396489 discloses a supplementary fold device suitable for apparatuses intended for the field of metal rods for reinforced concrete. Such device is able to create folds in a metal wire on different planes with respect to the work plane, allowing in this way the shaping of tridimensional stirrups in an easy way. Known solutions of this type comprise two clearly distinct fold units, operatively aligned along the rod feeding axis, which, therefore, do not allow to easily make structures of reduced size. Moreover, the presence of two fold units, besides burdening on the apparatus costs, may also be an obstacle to the working of bidimensional stirrups. In order to remedy this problem, the two fold units are arranged reciprocally spaced from one another at a certain distance, penalizing nevertheless the production of tridimensional elements which often require the alternation of folding phases between the two fold units and the transfer from one unit to another till the product is complete.

Disclosure

The task of the present invention is that of solving the aforementioned problems, devising a method and an apparatus which allow to make in an optimal manner both bidimensional and tridimensional stirrups.

Within such task, it is a further scope of the present invention that of providing for a method and an apparatus which enable to make tridimensional stirrups having any size and shape.

Another scope of the present invention is that of providing an apparatus for making tridimensional stirrups having a simple conception, a securely reliable functioning and versatile use, as well as relatively economic costs.

The cited scopes are attained, according to the present invention, by the method for making stirrups according to claim 1 , as well as by the apparatus for making stirrups according to claim 9.

The method for making stirrups provides to prearrange at least one handling unit for a metal rod feeding and/or backing according to a handling direction, a fold unit provided with a central folding mandrel and with an eccentric fold pin rotatable about a central mandrel for folding the same metal rod. The fold unit works on a work plane represented by the geometrical plane orthogonal to the central mandrel axis and comprising the above mentioned handling direction. A grip means mobile transversally to the work plane is provided so as to intercept the metal rod to be folded, the grip means being as well rotatable about the axis of the intercepted metal rod in order to rotate the same intercepted metal rod and perform the folding by means of said fold unit for making a tridimensional stirrup.

The method provides then to handle the metal rod along the handling direction by means of the above mentioned handling unit; performing the folding of the metal rod on the above mentioned work plane by means of the fold unit, by operating in rotation the eccentric folding pin about the central mandrel in suitable step relationship.

The method provides as well, in suitable step relationship with the cited handling and with folding steps, to operate the grip means in a direction transversal to the work plane for intercepting and tightening the rod.

According to the method object of the invention, when the rod is tightened by the grip means, the other members which are in contact with the rod release it. The grip means rotates about the axis of the tightened rod, in a controlled way, thus producing the corresponding rotation of the same rod.

The axial rotation of the rod, tightened by the grip means, enables the fold unit to make a tridimensional stirrup. In particular, the method provides to perform a sequence of folding steps of the rod by means of the same fold unit suitable to perform such folding steps on the same work plane, which orientation is fixed. When the rod, which has already at least partially been folded, is axially rotated, its folds, which have been already made, result oriented on respective surfaces, or fold planes, correspondently rotated, distinct from the work plane on which the fold unit, having fixed orientation, works.

The rotation of the metal rod performed by the grip means occurs in controlled way, so as to ensure the making of the tridimensional stirrup according to the desired design.

Moreover, in the rotation step, it is important that the rod is free as much as possible, that is, being gripped merely by the grip means, at least for a considerable tract, so as to avoid or minimize twisting stress.

The apparatus according to the invention comprises, in a corresponding way, a fold unit, working in an operative station for the tridimensional folding of a metal rod on a respective work plane. The apparatus comprises a handling unit for handling and leading the rod to the fold unit, feeding and/or backing, and grip means mobile transversally to the cited work plane and rotatable about the handled rod, for intercepting, tightening and rotating the same rod about the same direction.

As it was said before, the rotation of the grip means, mobile on the work plane and substantially rotatable about the handling direction of the rod, allows to perform a series of folds for making tridimensional stirrups, starting from a handled metal rod, feeding and/or backing, along the above mentioned handling direction.

Moreover, the handling unit can be alternatively operated between an active configuration, gripping the rod to be handled, and an inactive configuration, releasing the same rod. In particular, the grip means can be made up of one or more jaw clamps, foldaway mobile transversally to the work plane.

The above mentioned jaw clamps can be interposed between the handling unit and the fold unit for intercepting an intermediate portion of the metal rod to be worked.

According to a particular embodiment, the apparatus comprises a cutting and measuring station and transferring means from the cutting and measuring station to the operative station wherein the cited fold means, the grip means and the feed means are provided. In particular, the operative station for the bidimensional and tridimensional folding of the metal rod can be placed on a different level, preferably parallel and overlaying with respect to the cutting and measuring station, in which the rod is firstly drawn and then possibly straightened.

As an alternative, the operative station for the bidimensional and tridimensional folding of the rod can be placed on the same plane of the drawing and measuring station. In such case, the cited transferring means performs the transferring of the rod by shifting on the same work plane.

In both cases, a main drawing unit is preferably present, and the cited external handling unit is associated with it, opposed with respect to the fold unit.

As a further alternative, according to a further embodiment of the apparatus object of the invention, the handling unit for the tridimensional folding can coincide with the main drawing unit. In such case, the above described transferring means cannot be provided, since the feeding and cutting steps occur on the previously described work plane, on which the fold unit and the handling unit are suitable to cooperate. In such case, the cut means works on the already folded piece, instead of on the rod which is being fed and handled.

In any case, the apparatus results to be really compact and able to make a series of extremely close folds, for making tridimensional stirrups.

As a consequence, the specific limits of known apparatuses comprising two different and separated or reciprocally integrated folding heads, requiring repeated displacements of the working operations between the two heads and producing a considerable waste of energy and time, in spite of the overall performance of the apparatus, are overcome. It is as well to be underlined that the apparatus according to the invention does not entail risks about a wrong positioning of the stirrup being formed during the working steps, while in known apparatuses the need of repeated displacements considerably increases such risk, until the complete discharge of the piece from the working members, also because of the inevitable deformations of the row material.

It is to be observed that the grip means does not interfere in the functioning of the other working unit of the apparatus. Therefore, the apparatus allow to make a series of folds on reciprocally oblique planes, for easily making bidimensional and tridimensional stirrups. Moreover the apparatus is intended to realize indistinctively both bidimensional and tridimensional kind of stirrups.

Description of Drawings

Details of the invention shall be more apparent from a detailed description of a preferred embodiment of the apparatus for making tridimensional stirrups according to the invention, illustrated for indicative purposes in the attached drawings, wherein:

figures 1 to 14 show a perspective view of the apparatus for making tridimensional stirrups object of the invention, in a sequence of operating steps;

figures 15a and 15b show a perspective view of the same apparatus in different final working steps;

figures 16 to 27 show a perspective view of the apparatus for making tridimensional stirrups object of the invention in a second embodiment, in a sequence of working steps; figures 28a and 28b show a perspective view of the apparatus shown in figures 16 to 27 in different final working steps;

figure 29 shows a perspective view of a further embodiment of the apparatus according to the invention;

figures 30 to 37 show a perspective view of the apparatus shown in figure 29 in following working steps; figures 38a and 38b show a perspective view of the same apparatus illustrated in figure 29.

Best Mode

With particular reference firstly to figures 1 to 15a, 15b, the apparatus for making bidimensional and tridimensional stirrups according to the invention is indicated in its entirety with 1 . The apparatus comprises an operative station 10 for the folding, particularly tridimensional, on a work plane 2 on which a metal rod 3 is handled feeding and/or backing, according to a handling direction A. More in particular, the operative station 10 of the apparatus 1 firstly comprises a handling unit 4, for exemplar supplementary or external with respect to a main drawing unit not shown in figures and working upstream of a cutting and measuring station, as it is better described in the following. The operative station 10 comprises as well a fold unit 5 for folding the handled rod 3. Preferably, the fold unit 5 is made up of a traditional folding head, provided for example, in known way, with a central mandrel 6 or with a template and with an eccentric fold pin having axes parallel to one another and substantially orthogonal to the work plan 2, so as to fold the metal rod 3 on the same plane 2. More precisely, the eccentric fold pin 7 is operated rotatable about the central mandrel 6, so as to fold the metal rod 3 on the work plane 2 according to the winding produced about the central mandrel 6. Nevertheless it is possible to provide the use of a folding head of different type, which is suitable to make the folding of the metal rod 3 on the work plane 2.

In practice, the work plane 2 represents the geometrical plane orthogonal to the axis of the central mandrel 6 and containing the handling direction A.

Preferably, the handling unit 4 is made up of couples of handling or drawing wheels, counter-rotating and opposite with respect to the above mentioned handling direction A, for peripherally engaging and drawing the rod 3. The drawing wheels 4 can be arranged on the work plane 2, coplanar, so as to shape between them, at the handling direction A, a passage channel 8 for the rod 3. More precisely, the drawing wheels 4 can be operated, in each couple, alternatively between an inactive configuration and an active configuration. In the inactive configuration, the opposite wheels 4 are arranged separated from each other, for widening the passage channel 8 so as to receive the rod 3 to be handled towards the fold unit 5.

In the active drawing configuration, the drawing wheels 4 are approached to each other for tightening the rod 3 prearranged in the passage channel 8. A respective command means, not represented in drawings, is prearranged for mutually approaching and spacing the drawing wheels 4 of each couple, synchronically, and for driving in rotation at least one wheel of each couple. The driving in rotation of the drawing wheels in approached active configuration causes the feeding of the rod 3 tightened between the same wheels. In the illustrated case, the external drawing unit 4 comprises two couples of opposed drawing wheels, but the apparatus 1 according to the invention can comprise as well a different number of them.

The metal rod 3 to be fold for making a stirrup, in particular a tridimensional one, can be cut, for example by means arranged upstream of the operative station 10. As an alternative, it is possible to provide that the apparatus is prearranged for folding tridimensional stirrups starting from a rod 3 which has not yet been cut, as it is described in the following.

In the case disclosed in figures 1 to 15a and 15b, the rod 3 reaches the handling unit 4 joined to the row material which is located upstream, and after being tightened by the wheels of the handling or external drawing unit 4 is cut to size (see for example figures 5 and 6). More precisely, the disclosed apparatus comprises as well a feeding and cutting station 20, in which the metal rod 3 coming from a bar or unwound from a coil not represented, is prearranged along a feeding and cutting direction A ₀ , possibly straightened through a straightening device non illustrated, for example having counter-rotating rolls, for being cut to measure by a cutting member 22. In particular, the wheels of the straightening unit can be suitably protected by a protection housing so as to avoid any interference with the handled rod 3 during the working.

The apparatus 1 can therefore comprise transferring means for transferring the rod 3, which have been cut to measure, from the feeding and cutting station, in which the straightening unit, possible in case the row material is a coil, and the cutting member 22 work, to the operative station 10, in which the work plane 2 is defined and in which the fold unit 5 and the external drawing unit 4 work, for making bidimensional and tridimensional elements.

In the illustrated case, for example, the feeding and cutting station 20 and the work plane lay upon different levels or planes. Therefore the transferring means, which is made up of known command means, not represented, is suitable to perform the shifting of the external drawing unit 4 and of the fold unit 5 from the level in which the rod 3 is located for its feeding and cutting to the level of the work plane 2, respectively reaching the configuration 4b and 5b, shown in figures 4 to 15a and 15b.

In practice, in the disclosed case, the feed and cut level is on a plane which is substantially parallel to the work plane 2. The transferring means alternatively performs the required shifting motion, suitable to transfer in suitable sequence the working units of the operative station 10 to a plane spaced from the feed and cut plane so as to enable the rod to be displaced above the cut members for its unwinding, without interferences of the folding operations. Moreover, the transferring means performs the placing of the cited units preferably in separated and autonomous manner on each unit. More precisely, the drawing unit 4 can be transferred and placed on three working levels: a position 4' on a first level, underlying the feed and cut plane, which does not engage in any case the space engaged by the feed and cut operations or by the making of bidimensional stirrups; a position 4a on a second level, lifted and parallel to the first, in which the drawing unit is arranged on the feed and cut plane, for intercepting the feeding rod 3; a position 4b on a third level, lifted with respect to the above mentioned second level, coinciding with the work plane 2, for making tridimensional stirrups. In the same way, the fold unit 5 can be placed by the above mentioned transferring means for being prearranged on the level suitable to allow the different working steps. For example, the fold unit 5 can be transferred at least from the configuration 5a on the cited second level, for carrying out the folding of the feeding rod 3 or for receiving the same rod, freely passing, to the cited configuration 5b on the cited third level, for cooperating with the drawing unit in the corresponding position 4b for making tridimensional stirrups.

The apparatus 1 comprises as well a grip means 1 1 which is suitable to intercept the handled rod 3 and substantially rotatable about the handling direction A on the work plane 2. The grip means 1 1 is suitable to tighten and to rotate the rod 3 for a determined angular width about the handling direction A on the work plane 2, in order to bring sections correspondently turned of the rod 3 to the same fold unit 5 and thus to enable the folding of the same rod 3 on laying planes being oblique to one another, for making a tridimensional product.

For laying plane of any fold it is meant in particular the plane defined by tracts of the rod converging towards a folded rod portion.

The grip means 1 1 is preferably interposed along the handling direction A between the fold unit 5 and the drawing unit 4 and it can act as well as an abutment during the folding step.

The grip means 1 1 is preferably made up by a jaw clamp, which can be operated in sequence among different positions. In an inactive position, the pincer 1 1 is spaced from the handling direction A in which the rod 3 is fed or backed by the drawing unit 4 on the work plane 2. In an interception position 1 1 a, the jaws 12 of the pincer are interposed open along the handling direction A between the drawing unit 4 and the fold unit 5 on the work plane 2. In a tightening position the jaws 12 of the pincer 1 1 are tightened along the handling direction A gripping the rod 3. Finally in a tightened turned position 1 1 b the jaws 12 are kept tightened and turned substantially about the handling direction A of an angle having determined width, for rotating in correspondent manner the metal rod 3 to be fold. Substantially, the pincer 1 1 is operated mobile through the work plane 2, for example perpendicularly, for protruding through an opening obtained on the work plane 2, from the described inactive position, preferably underlying the work plane 2, to the interception position 1 1 a of the rod 3, protruded with respect to the above mentioned work plane 2 and with the jaws prearranged for receiving between them the rod 3.

[52] The controlled rotation of the pincer 1 1 is performed by command means of known type, in suitable step relationship with the feeding and folding operations of the rod by means of the fold unit 5.

[53] The functioning of the apparatus for making bidimensional and tridimensional stirrups is easy to understand from the previous description.

[54] The metal rod 3 is firstly prearranged in the feeding and cutting station 20 in which the main drawing unit 21 and the cutting member 22 operate. More precisely, in the first step, the rod 3 is fed on the working level of the feeding and cutting station 20, according to the feeding and cutting direction A ₀ (see figure 2). In the same step, the fold unit 5 and the external drawing unit 4 are both spaced from the work plane 2. More precisely, in a first step, the drawing wheels 4 lay rearward at the described first level, in order not to interfere with the feeding operations of the rod, or at the second level but with the wheels spaced from each other in the inactive configuration. In the same way, the fold unit 5 can be in a rearward position below the work plane 2 or arranged on the cited second work level, so as to freely receive the feeding rod 3, between the central mandrel 6 and the eccentric pin 7 (see figure 2). Subsequently, according to the case, the drawing unit 4 is operated by the transferring means for being brought to the second work level, in inactive configuration, that is with the wheels reciprocally spaced, so as to freely receive in the passage channel 8 the rod 3 feeding along the feeding and cutting direction A ₀ . The fold unit 5 is placed so as to freely receive the rod 3 passing between the central mandrel 6 and the eccentric folding pin 7 (see figure 3).

[55] When the rod 3 is fed in the feeding and cutting direction A ₀ for a tract of predetermined length, the drawing unit 4 is operated in the active tightening configuration, so as to engage the rod 3. Subsequently, the cutting member 22 is operated for cutting to measure the fed rod 3. By keeping the grip on the cut rod 3, the drawing unit 4 together with the fold unit 5 are brought to the third level, coinciding with the work plane 2, through the activation of the transferring means (see figure 4 and 5).

[56] At this point, the folding steps for the rod 3, which has been cut to measure, start, by performing the controlled feeding or backing of the rod 3, along the handling direction A on the third level, parallel to the feeding and cutting direction A ₀ previously cited, by means of the drawing unit 4, so as to position the rod 3 in suitable way with respect to the central mandrel 6 and to the eccentric pin 7, so as to perform the desired folds. In suitable step relationship, the grip means 1 1 is operated for tightening corresponding portions of the rod 3, and for rotating the same rod 3, so as to make folds laying on different planes, in order to obtain tridimensional stirrups. As an example, according to the folding cycle shown in figures 6 to 15a, 15b, the rod 3 is firstly backed with respect to the handling direction A (see fig 6), folded by the fold unit 5 on the work plane 2 (see figure 7), being the pincer 1 1 in an inactive position, underlying the same plane. More precisely, for "backing" it is meant the displacement along the handling direction A, oriented from the handling or drawing unit 4 towards the fold unit 5. Subsequently, the rod 3 being worked is again backed with respect to the handling direction A and, at the same time, the pincer is led in the interception position 1 1 a, with the jaws firstly opened, so as to freely receive the rod 3, then closed (see figure 8).

The drawing unit 4 releases then the rod 3, for allowing the pincer 1 1 to be operated in rotation until reaching the rotated configuration 1 1 b, for performing a corresponding rotation of the worked rod 3 (see figure 9). In the shown case, the rod 3 is rotated of an angle substantially equal to 90° about its axis, substantially corresponding to the handling direction A, which results, as previously described, parallel but on a different level with respect to the feeding and cutting direction A ₀ .

Then, a second fold is made by the fold unit 5, creating tracts on distinct planes of the stirrup being made (see figure 10).

Subsequently, the pincer 1 1 releases the rod 3 and comes back to the inactive position below the work plane 2. Then the worked rod 3 is brought back again with respect to the handling direction A in order to position a new portion to be folded at the fold unit 5 (see figure 1 1 ).

Then a new folding of the rod 3 is made on the work plane 2 by the fold unit 5 (see figure 12). The rod is again backed by means of the drawing unit 4 (see figure 13), tightened by the pincer 1 1 , released by the drawing unit 4, for being again rotated about the handling direction A, for example of an angle substantially equal to 90° (see figure 14).

Finally, the rod is folded in one direction or in an opposed one, according to the shape of the stirrup to be produced (see figures 15a, 15b) and released by the pincer 1 1 which comes back in the inactive position for freeing the stirrup. The pincer 1 1 can remain in the gripping position even during the folding step, acting, in an efficient way, as an abutment, thanks to its closeness to the fold unit 5. In fact, the pincer 1 1 is closer to the fold unit 5 than the drawing unit 4 which can act as abutment too.

According to a different embodiment, shown in figures 16 to 28a and 28b, it is possible to provide, as an alternative, that the feeding and cutting station 200, comprising the main drawing unit, and the operative station 100, for the tridimensional folding, are substantially coplanar, that is on the same work plane 2. More precisely, in such case, the handling direction B, aligned with the drawing unit 40, this latter being opposite to the main drawing unit, results parallel and shifted with respect to the feeding and cutting direction A ₀ . In particular, the fold unit 50 is carried mobile by the cited transferring means between a starting position 50a, in which the unit is suitable to make bidimensional stirrups, and a displaced position 50b, for example arranged below on the same work plane 2, for making tridimensional products.

[65] In such case, for example, the feeding and cutting direction A ₀ is substantially parallel to the handling direction B for folding the rod 3, and laying on the same work plane 2. The fold head 50 is then carried mobile on the work plane 2, between the starting position 50a, at the feeding and cutting station 200 aligned to the feeding and cutting direction A ₀ , and the shifted position 50b aligned with the handling direction B. As an alternative, an autonomous fold head can be provided for each position 50a and 50b of the fold unit.

[66] Substantially, in such case, the rod 3 to be fold is not handled between levels parallel to the work plane 2, as it was in the previously described case, but it is shifted on the same work plane 2 between a positioning aligned to the feeding and cutting direction A ₀ and a shifted positioning, aligned to the handling direction B for the tridimensional folding (see figure 17).

[67] The working steps for making a tridimensional stirrup starting from the rod 3 cut to measure are performed as previously described (see figures 18 to 28a 28b). In particular, in the shown embodiment further members of known type can be provided, for example an auxiliary pincer, suitable to cooperate for the shifting of the rod 3 being made between the cited directions. As a further alternative, the rotatable grip means 1 1 can be mobile for performing as well the transferring of the rod 3 from the position aligned to the feeding and cutting direction A ₀ to the handling direction B.

[68] According to a further embodiment of the apparatus according to the invention, shown in figures 29 to 38a, 38b, it is possible to provide that the rod 3 is fold and rotated for making tridimensional stirrups, before being separated from the raw material in bars or coils. Substantially, the main drawing unit 201 provided for equipping the feeding and cutting station or, in case the row material is in coil, the feeding cutting and straightening station, acts also as external drawing unit 4 as previously described, thus being suitable for the handling of the row material to the operative station 101 for making tridimensional products. According to such embodiment, it is therefore possible to proceed with separating the product from the row material by means of the cutting means 221 only at the end of the folding steps at the work station 101 .

[69] Moreover, it is to be noted that, in such case, the handling direction A in the operative station 101 coincides with the feeding, cutting and possible straightening direction A ₀ .

[70] More precisely, in the illustrated embodiment the only present drawing unit is the main one 201 , arranged for example in a suitable housing, upstream of the fold unit 5, while the grip means 1 1 comprises ore or preferably more pincers which can be arranged upstream of the drawing unit 201 and the fold unit 5 and/or downstream of this latter (see figure 29). [71 ] The presence of a plurality of suitably spaced pincers 1 1 allows to synchronically tighten and rotate a corresponding plurality of portions of the worked rod 3, so as to obtain an optimal grip and the desired rotation of the rod 3 interposed between the tightened sections, for allowing the making of the required tridimensional product.

[72] Obviously, it is possible to make bidimensional and tridimensional stirrups of any shape, by simply combining in suitable way the feeding, the backing, the rotation and the folding of the rod 3 by means of the fold unit 5, of the drawing unit 201 and of the grip means 1 1 .

[73] The apparatus in object attains the scope of performing in an optimal and quick way the automatic making of tridimensional as well as bidimensional stirrups and it is susceptible of numerous variants. For example, it is possible to provide that the grip means, such as one or more jaws and the relative mechanical members, are housed and supported by structures overlaying instead of underlying the work plane 2, mobile transversally to it from a lifted position to a lowered position on the work plane 2, so as to free the space engaged by the working members, in suitable step relationship with respect to the folding steps.

[74] A characteristic of the apparatus lays in the extreme compactness of the different working units, which allows in particular to make tridimensional stirrups of reduced size.

[75] In practice, the embodiment of the invention, the materials used, as well as the shape and dimensions, may vary depending on the requirements.

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