METHOD AND APPARATUS FOR MAKING REINFORCEMENTS FOR

REINFORCED CONCRETE

Technical Field

[01 ] The present invention regards a method and an apparatus for making reinforcements for reinforced concrete and other tridimensional articles, in particular spiral reinforcements and the like.

Background Art

[02] It has been known that, in order to make the reinforcement of reinforced concrete pillars and girders, metal cages are commonly used consisting of longitudinal metal wires, in particular iron rods, linked by transverse stirrups suitably spaced. The realization of such metal cages is usually rather complex and requires considerable execution time, with sensible waste of manpower and proportionally elevated costs.

[03] In alternative to the use of the traditional stirrup metal cages, the use of so- called continuous clamping reinforcements, realized though the spiral winding of a rod substantially in the shape of a "spring" of the required length, has been proposed. It has been noted that such reinforcements have better resistance characteristics, with respect to the traditional metal cages.

[04] Nevertheless the spiral reinforcements are difficult to make, as they require the use of machines more complex than the traditional ones and imply elevated costs reported to the economic value of the product.

[05] A specifi c d rawback com p l a i ned i n th e rea l izati on of the cited reinforcements consists of the fact that according to the traditional realization methods all the sides of the spiral are inclined, which results unacceptable from a project point of view. In facts the reinforcement of the girders has the task of absorbing the shearing stresses, that is why the lack of a perfect verticality of the tracts or "arms" of the clamping provided as vertical results unacceptable.

[06] In the specified sector, m ultiple solutions designed to improve the realization of the spiral reinforcements have been proposed. For example, European patent application EP 0 864 386 describes a method and an apparatus for making leaning coils reinforcements, which is substantially without pitch, starting from a metal wire. Such an apparatus substantially consists of a wire folding unit fixed on a mobile frame which is shifted in the feed direction of the same wire. The apparatus further comprises a device for collecting the coils which is shifted perpendicularly to the direction of the fed wire and in the meantime rotates in such a way that the angle of the coil being produced in this moment is on the feed line of the wire.

[07] Patent application WO 2010/044052 describes a method and an apparatus for making reinforcements having a particular spiral-shaped geometry with a not null and predetermined pitch, which provides a fold in the third dimension of the oblique tract of the spiral.

[08] A further known typology of machines for making the cited articles consists of the so-called tridimensional machines, which provide the rotation of the folding head for 360° about the axis of the rod being fed. The drawback of such machines consists of the fact that the item exiting from the folding head inevitably follows the rotation of this latter. Such a rotation in the space of the article in formation creates considerable and sometimes insurmountable difficulties for the control and the collection of the same article when this latter has a considerable length, as in the case of the spiral shapes required in the building sector. Such a solution is therefore efficient for the production of small dimensions elements such as for example springs for the mechanics and the like, but is not adapted to the production of articles having a considerable extent like the continuous reinforcements for reinforced concrete.

[09] Another known method in the sector for making tridimensional shapes consists of performing a sequence of folds spaced by the rotation of the piece being shaped with respect to the axis of the raw material. Such a solution can apply only in the case of pieces the lengthwise development of which results lim ited and therefore is not usable for the production of continuous reinforcements the development of which reaches various dozens of meters and necessarily requires to be fed by wire coils.

Disclosure

[10] The task of the present invention is that of solving the aforementioned problems, devising a method which allows to realize i n a simple and efficient way continuous spiral reinforcements for reinforced concrete the extent of which reaches dozens of meters and tridimensional elements generally starting from metal wire in coil, as well as an apparatus for performing the same method.

[1 1 ] Within such task, it is a further scope of the present invention that of providing a method and an apparatus which enable to make, with a suitable operating sequence, tridimensional continuous reinforcements having a predetermined pitch, constant of variable at will, along the longitudinal axis of the reinforcement.

[12] A further task of the present invention is that of providing a method and an apparatus which allow to make spiral reinforcements with arms suitable to be arranged vertically in the configuration of use as described in patent EP 1 469 135 A1 .

[13] A further scope of the present invention is that of providing a method and an apparatus which enable to realize reinforcements of any geometry, extension and dimension, with metal wires or iron rods of any diameter fed from a coil.

[14] Another scope of the present invention is that of providing an apparatus for making reinforcements for reinforced concrete having a simple conception, a securely reliable functioning and versatile use.

[15] The cited scopes are attained, according to the present invention, by the method for making reinforcements for reinforced concrete according to claim 1 , as well as by the apparatus for making the same reinforcements according to claim 4.

[16] The method for making polygonal profiled reinforcements for reinforced concrete through the folding of a metal wire, consists of the steps of:

[17] a. feed ing the wire through unwind ing from a coi l , accord ing to a longitudinal feed axis, through a folding unit arranged along the same longitudinal feed axis, for shaping a series of folding of the metal wire, each folding being located on a respective folding plane defined between a couple of tracts of wire concurrent to a respective folding vertex;

[18] b. performing through the folding unit a first folding of the metal wire on a first folding plane; c. performing the feed of the wire according to the longitudinal feed axis of the tract necessary for making a side of the reinforcement being formed; d. performing the axial rotation of the wire being unwound substantially associated with a corresponding revolution rotation of the coil about the same longitudinal feed axis of the wire;

e. performing through the folding unit a second folding in sequence to the first one, the second folding resulting located on a respective second folding plane rotated with respect to the first one by an angle substantially equal to the axial rotation imposed to the wire being unwound between the first and the second folding, determining a corresponding tridimensional extension of the reinforcement being formed.

Substantially the entity of the tridimensional extension of the reinforcement being formed is determined in a precise way, according to a trigonometric relationship, on the basis of the entity of the longitudinal feed between a folding and the successive one and of the entity of the axial rotation imposed to the wire. It is to be noted that the method does not generate any torsional tension in the wire being worked as the rotation involves both the wire portion still wound in the coil, and the already unwound portion being axially feed, and the article being formed.

It is also important to observe that the motion of the exiting article is a complex movement, function of the geometry to be made, but the direction of the resultant of the motion of the exiting article substantially follows an axis orthogonal to the folding plane and to the feed axis; that makes possible the control and the collection of the article being formed, which is impossible to be realized with any other known system. Practically, following the axial rotation imposed to the wire between the performing of a first folding and of the successive one, the spiral being formed extends in a third direction exiting from the plane of the first folding made, thus assuming a tridimensional extent and shape. The entity of such an extent is controllable in an efficient manner, suitably actuating the feed and the axial rotation of the wire, together with the revolution rotation of the wire coil in order to avoid excessive torsional tensions.

In the particular case of the spiral tridimensional reinforcements, the tridimensional extent defines the pitch between the coils. The method therefore enables to make the pitch of spiral reinforcements in a precise way, according to the same trigonometric relationship, that is as a function of the length of the tracts of metal wire between two successive folds and of the width of the cited axial rotation imposed to the wire.

Thanks to the method in hand, suitably combining multiples steps of feed, rotation, revolution and fold , it is possible to make trid im ensional reinforcements of any type and also spiral reinforcements of any shape. In particular the pitch between the coils and the geometry of these latter turn out to be controllable and so obtainable in a very precise way. The method, through a particular operating sequence, further allows to make the spiral reinforcement with vertical arms as in patent EP 1 469 135 A1 .

Preferably the method provides to further perform the straightening of the wire being unwound and to rotate axially, in a substantial synchronism, both the coil being unwound and the straightening unit according to the same longitudinal unwinding axis.

The apparatus according to the invention comprises a reel for unwinding according to a longitudinal feed axis a wire wound in a coil, a drawing unit suitable to feed in advancement the wire according to the same longitudinal feed axis, as well as a folding unit cooperating for form ing a series of folding of the wire. In particular, each fold is located on a respective folding plane defined by a couple of tracts of wire, concurrent to a respective folding vertex. The apparatus further comprises a unit for supporting the reel, rotatable in revolution about the axis of longitudinal feeding of the wire. Said revolution motion is actuated in order to follow the axial rotation of the wire being unwound, enabling to perform successive folding on reciprocally rotated folding planes for the formation of tridimensional reinforcements. In a preferred embodiment, the axial rotation of the wire is imparted through the rotation about the same axis of the drawing unit maintained in grip on the same wire. The apparatus can further comprise a straightening unit associated with the drawing unit, in rotation as well.

In a different embodiment it is provided that the axial rotation is imparted to the wire by suitable clamping members provided with rotation movement, while the drawing unit and the possible straightening unit do not rotate. In a further embodiment, the drawing unit consists of one or more jaws shifting along the axis of the wire the clamping means of which are able to transmit to the wire both the axial rotation movement and the feed motion. In association with any embodiment, the support unit of the reel is set in revolution in a substantially synchronized way to avoid excessive torsional tensions.

Description of Drawings

Details of the invention shall be more apparent from the detailed description of a p refe rred em bod i m ent of the apparatus for making spiral reinforcements for reinforced concrete and similar tridimensional extent products, illustrated for indicative purposes in the attached drawings, wherein:

[34] f i g u re 1 s hows a perspective view of the apparatus for making reinforcements for reinforced concrete in hand;

[35] figures 2 and 3 respectively show a lateral view and a plant view thereof;

[36] figures 4 and 5 respectively show a perspective view of a reel and of a drawing unit of the apparatus in hand;

[37] figures 6 and 7 respectively show a perspective view of a folding unit of the same apparatus, according to different operating modalities.

Best Mode

[38] With particular reference to such figures, is indicated in its entirety with 1 the apparatus for making reinforcements for reinforced concrete, in particular tridimensional reinforcements of the spiral, U-bolt, distance type and the like, starting from a wire 2, for example an iron rod fed from a coil.

[39] The apparatus 1 comprises means for feeding the wire 2, wound in a coil 2a, according to a predeterm ined longitudinal feed axis A, preferably arranged horizontally. The coi l 2a is carried by unwind ing means 3 consisting for example of a reel suitable to drive the coil also in a revolution movement. In the illustrated case, such means for feeding the wire 2 are usefully constituted by a drawing unit 4 suitable to perform the drawing of the wire 2 being unwound from the reel 3 along the longitudinal feed axis A. In particular the drawing unit 4 is arranged according to the aforesaid longitudinal feed axis A in a way as to receive the wire 2 being unwound from the reel 3 to perform the drawing thereof. The drawing unit 4 can comprise, as in the illustrated case, a straightening unit 7 for straightening the wire 2 being unwound, arranged according to the same longitudinal feed axis A.

Downstream of the drawing unit 4, according to the feed direction of the wire 2, is arranged a folding unit 5 of the wire 2. Preferably between the drawing unit 4 and the folding unit 5 is arranged a shear unit, for simplicity not represented in the drawings.

The folding unit 5 is suitable to perform successive folding of the wire 2 with respect to the longitudinal feed axis A, to produce, side after side, polygonal profiled reinforcements, in particular tridimensional shaped reinforcements. In figures 6 and 7 is illustrated as an example, in formation, a continuous clamping 20 wherein a succession of coils 21 is designed to shape a spiral- shaped tridimensional structure, as better explained in the following.

The folding unit 5 comprises, in a known way, a folding head 6 provided with a folding pin which is suitable to perform a flexure of the wire 2, and therefore a folding, centred with respect to the axis of a central pin. The obtained folding is therefore localized on a folding plane defined between a couple of tracts of wire 2, concurrent to a respective folding vertex V. In the case i llustrated in figures 6 and 7 the obtained folding has a width substantially equal to 90°, and therefore is suitable to realize quadrangular coils. Obviously it is possible to obtain coils of any polygonal shape, varying suitably the width of the folding angle.

Under the folding unit 5 is preferably arranged a collection device 8 for the produced coils 21 , with a substantially vertical axis. The collection device 8 is preferably of the type illustrated in patent application IT BO2008A000030 which is considered included for reference.

[44] According to the present invention, the apparatus 1 comprises a rotatable unwinding unit 30 suitable to drive the reel 3 in a revolution motion with respect to the longitudinal feed axis A of the metal wire 2. In practice, the reel 3 is rotatable according to two axis preferably perpendicular: a first rotation axis B for unwinding the wire wound in the coil 2a and a second revolution axis about the longitudinal feed axis A of the metal wire 2. In the illustrated solution, the unwinding unit 30 is realized by a cylindrical cage 31 preferably coaxial to the feed axis A of the wire 2, suitable to contain in its own inside the reel 3. The reel 3 is arranged inside the cage 31 with the unwinding axis B preferably perpendicular to the feed axis A of the wire 2. The cage 31 is mounted on a fixed support 32 through the interposition of revolving support means 33 mounted rotatable on the support 32. The cage 31 is suitable to be driven in the revolution motion about the feed axis A by a motor member of known type, to meanly follow the axial rotation of the wire.

[45] The motor member is suitable to produce the revolution motion of the reel 3 preferably in a continuous manner, in a way as to limit the inertia effects due to the variations of the motion of the unit.

[46] The cage 31 comprises laterally a guide member 34 of the wire 2 realized for example by a ring arranged on the feed axis A, peripherally to the cage, inside which is suitable to be inserted passing the wire 2 to be drawn in advancement by the drawing unit 4; alternatively the guide member can be constituted by a roller cage suitable to reduce the effect of the friction. The whole unit 30 is suitable to perform a double rotation movement: a first rotation movement about the axis B and a second revolution movement about the feed axis A, possibly in synchronism with the corresponding rotation of the drawing unit and, if provided, of the straightening unit, as better described in the following.

[47] The apparatus can also comprise a support unit 40 for the drawing unit 4, rotatable about the longitudinal feed axis A of the wire 2 (see in particular fig. 5). The apparatus can provide that also the straightening unit 7 is rotatable about the same axis.

[48] The support unit 40 is preferably made by means of a drum 41 carrying coaxial the drawing unit 4. The drum 41 is carried rotatable by a fixed frame 42 through the interposition of revolving support members 43. The drum 41 can be driven in rotation to perform a rotation of controlled width according to the longitudinal feed axis A of the wire, through actuation means of known type, preferably controlled by suitable processing means. The drawing unit 4 is therefore suitable to be taken in rotation integrally to the drum 41 upon control of the cited actuation means. By effect of such a controlled rotation, the metal wire 2 carried in grip by the feed members of the drawing unit 4 is suitable to undergo a corresponding axial rotation, along the longitudinal feed axis A.

[49] Preferably, the drawing unit 4 is in turn actuated by means of an electrical connection device having sliding contacts to warrant the correct functioning in any rotation condition about the longitudinal feed axis A. It is to be observed that the sliding contacts are carried by a bobbin 45 crossed by the wire 2. To the drum 41 is further made integral, according to the longitudinal feed axis A, a tubular member 46 suitable to accompany the wire 2 until the folding unit 5. The tubular member 46 is provided with grip means 47, for example consisting of a cam vice controlled by electromagnetic means, suitable to tighten the wire 2 during the rotation of the drum 41 , in a way as to warrant the uniform ity of rotation of the same wire 2 and so avoid torsional tensions in the tract of wire being worked.

The functioning of the apparatus for making reinforcements for reinforced concrete according to the method in hand is described in the following. For making a spiral reinforcement, the feed and the folding of an end tract of the metal wire being unwound from the reel 3 is controlled in a known way, so as to shape an initial fixing hook, usually at 1 35°. Then, if necessary, a first flat stirrup 22 is produced, called "template stirrup", suitable to be arranged on a plane substantially orthogonal to the longitudinal axis of the spiral reinforcement to be shaped. For making such a "template stirrup", for each side thereof is performed an appropriated series of feeds, by means of the drawing unit 4, alternated with fold steps, through the folding unit 5. Once prearranged the possible "template stirrup", one proceeds to the realization of the successive coils according to the desired pitch, constant or variable.

To such an end, in suitable step relation, a rotation is imparted to the metal wire about its own axis A, while the unwinding unit 30 of the reel 3 follows said rotation with a revolution rotation about the feed axis A, in such a way that both rotations result meanly synchronous. More precisely, the portion of the wire which is wound in the coil 2a, the portion being axially unwound, and the portion of wire already folded downstream of the folding unit 5 are driven in rotation.

Successively a second folding is performed, which thus results arranged on a folding plane rotated with respect to the plane of the first folding, by an angle substantially equal to the axial rotation imposed to the wire between a folding and the successive one.

Alternating in a suitable manner axial rotation steps of the wire associated with corresponding revolution rotations of the coil, and feed and folding steps, it is possible to obtain tridimensional reinforcements of any extent and shape. At the difference of other known solutions which enable the formation of tridimensional elements of only limited extent, the method and the apparatus according to the present invention allow to make continuous tridimensional reinforcements typical of the building sector.

The method according to the invention therefore attains the scope of making in a simple and efficient way reinforcements for reinforced concrete, in particular tridimensional reinforcements of any shape and dimension and in particular continuous spirals also of the type specified in patent EP 1 469 135 A1 .

Such a scope is attained thanks to the provision of axially rotating the wire 2 in substantial synchronism with the revolution movement of the support of the reel 30. In such a way it is possible to make a determined tridimensional shape, for example a continuous spiral having a variable or continuous pitch.

The described apparatus is susceptible of numerous modifications and variants, according to the diverse exigencies. In particular it is possible to provide that the axial rotation is imparted to the wire by suitable clamping members provided with a rotation movement, while the drawing unit and/or the possible straightening unit do not necessarily rotate. Obviously, if not rotatable, the drawing unit and/or the possible straightening unit result open during the axial rotation step of the clamping members.

Furthermore, the folding unit suitably rotating, the formation of the spiral reinforcement 20 can be developed according to any suitable direction transverse to the longitudinal feed axis A, for example in a vertical direction downwards as illustrated in fig. 6, or in an horizontal direction, as illustrated in fig. 7 wherein suitable support and collection means for the spiral are indicated with 9.

It is to be observed that the method in hand can be performed in association with any typology of reel arranged in such a way as to avoid torsional tensions of the worked wire.

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

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.