WO2023112070A1

WO2023112070A1 - Apparatus and method for bending bars

Info

Publication number: WO2023112070A1
Application number: PCT/IT2022/050331
Authority: WO
Inventors: Aronne Miglioranza
Original assignee: Schnell S.P.A.
Priority date: 2021-12-16
Filing date: 2022-12-14
Publication date: 2023-06-22
Also published as: IT202100031601A1

Abstract

The apparatus for bending bars comprises a bending unit (41) suitable for receiving on a work surface (a) at least one bar (2) according to a longitudinal direction (A), and a bending head (40) which can be engaged on the bending unit (41 ), at a bending axis (B). The bending head (40) comprises a bending mandrel (42, 45) and an eccentric pin (43) rotatable on the work surface (a) around the bending axis (B), to bend the bar (2) around the mandrel (42, 45).

Description

APPARATUS AND METHOD FOR BENDING BARS

Technical field

[01] The present invention relates to an apparatus and a method for bending bars, in particular metal bars, such as for example iron rods for reinforced concrete, obtained by cutting from bars or rolls.

Background of the invention

[02] The use of steel bars commonly called "bars", bent at one or opposite ends, in this latter case called "rebars", or of rods bent into a substantially closed section bar, called "stirrups" or "long stirrups" depending on the size, for making reinforcing bars for reinforced concrete is known. In order to manufacture these products, apparatuses that submit the ends of the straight or pre-straightened steel rod to a suitable series of bends are generally used. More specifically, bending apparatuses called "shaping robots or bending benches" are currently known, which permit to produce shaped products, stirrups or "long stirrups", starting from section bars already cut to a certain length suitable for the size of the shaped elements to be manufactured.

[03] Such apparatuses usually comprise a feed path with motorized roller, used to feed the bars to be shaped, manual, automatic or semi-automatic means for transferring or loading bars, and at least one bending unit or more commonly a pair of bending units, each carrying a bending head to shape a respective end of the loaded bars.

[04] In particular, each bending head comprises a bending tool normally consisting of a central bending mandrel and an eccentric bending pin, as well as an abutment which prevents the workpiece from moving.

[05] Alternatively, according to a known solution, the bending tool consists of a double mandrel crossed by a seat for the bars which also acts as an abutment during the bending step, carried out as well by an eccentric pin.

[06] In traditional apparatuses, each bending head is in any case constrained to the bending unit, which is fixed or movable in the longitudinal direction to the axis of the bar to be shaped. Apparatuses in which one bending unit is fixed, while the other is movable are known in the art. Apparatuses with operation similar to that described, in which both bending units are movable are also known in the art.

[07] Such apparatuses of the known type generally perform bending cycles, through an appropriate alternation of the steps of bending and of relative displacement between the bending units.

[08] In particular, between one bending cycle and the next, the replacement of the bending head may be required. The replacement of the bending tools may be necessary, for example, when the radius of curvature to be imposed on the bars changes and therefore it is necessary to install a bending head equipped with an appropriate mandrel.

[09] In apparatuses of the known type, the replacement of bending tools requires the intervention of the operator who, manually or semi-automatically, removes the bending head to be replaced and inserts a spare bending head.

[10] This operation, in addition to being difficult for the operator, due to the weight of the tools to be handled, requires the apparatus to be stopped and therefore slows down the throughput.

[11] Besides this, the known type of apparatuses does not permit to effectively automate the loading and unloading of the bars to the bending units.

[12] For example, patent EP1296780 discloses an apparatus for bending bars, comprising a transfer mechanism equipped with pliers, for feeding the bars into a bending system, and an unloading system also equipped with pliers, for unloading the shaped bars.

[13] Patent EP1375022, on the other hand, discloses a plant for processing metal bars, comprising means for transferring them.

[14] Patent US 5,182,932 discloses a further example of a bar bending apparatus, comprising a pincer conveying device, for transferring the bars to a bending unit.

[15] However, the known solutions do not fully suits the needs of the specific sector, since they generally have a complex structure, which is therefore bulky and expensive.

Disclosure

[16] The aim of the present invention is to solve the problems mentioned in the known art, by devising an apparatus and a method for bending bars that permits to automatically handle bending tools, facilitating their replacement.

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

[18] The aforementioned objects are achieved, according to the invention, by the apparatus of claim 1 , as well as by the method of claim 15.

[19] According to the invention, the apparatus for processing bar comprises at least one bending unit for machining the bars on a work surface.

[20] The bending unit comprises a bending head which provides for a mandrel, in particular a central mandrel, and an eccentric bending pin rotatably mounted around a central bending axis, preferably coincident, in a condition in which it is mounted on the bending unit, with the central axis of the mandrel.

[21] The bending head is mounted on the bending unit interchangeably.

[22] The apparatus further comprises a conveying device preferably interposed between a feeding station and a bar unloading station, comprising an articulated arm constrained to a height below the work surface and at least one gripping member articulated to the articulated arm at least about an orientation axis. The gripping member is movable between an open configuration for gripping or releasing and a closed configuration for holding.

[23] The bending head usefully shapes a gripping portion configured to be retained by the gripping member of the conveying device, arranged in the closed configuration.

[24] The conveying device is movable by a replacement motion between a first position in which the gripping member is arranged in a closed configuration at the bending head mounted on the bending unit, to retain the gripping portion, and a second raised position, in which the bending unit retained by the gripping member is drawn out from the work surface. It is possible to provide that in the first mentioned position the bending head is usefully arranged raised in a condition emerging from the work surface by means of suitable drawing or pusher means to be more easily engaged by the gripping member.

[25] The apparatus, as mentioned above, may further comprise a feeding station adapted to receive the bars on a feeding table and an unloading station, to receive the processed bars on a respective unloading table.

[26] Preferably the gripping portion can be advantageously provided on a non-operative side of the bending head, usually not used, opposite the eccentric bending pin. For this reason, the gripping portion can have the effect, on the aforementioned non-operative side of the bending head, of lightening the shape of the central mandrel, which can be suitably shaped, for example sectioned. This can result in an advantage in handling operations, especially for bending heads of considerable size.

[27] Alternatively, the gripping portion of the bending head may be shaped by the mandrel itself, for example being protruding along the central axis of the mandrel itself or along a substantially parallel axis.

[28] Advantageously, the same conveying device can fully automate both the replacement of the bending head and the transfer of the bars on the bending unit. More precisely, the conveying device can also be movable by a transfer motion to transfer the bars from and/or to the bending unit, gripping them by means of the aforesaid gripping member, in said closed configuration.

[29] Preferably the conveying device is operable in the transfer motion to bring the gripping member in a first transfer section between the feeding station and the operative unit and in a second transfer section between the operative unit and the unloading station, to release the number of bars respectively on the work surface and on the unloading surface.

[30] The conveying device can be advantageously operable in an orientation motion at least about the orientation axis, so as to orient the gripping member to collect and release the bending head and/or the bars from or to the operating unit.

[31] The orientation axis is preferably parallel to the longitudinal direction. [32] Preferably, this orientation motion causes the gripping member to tip over from one side to an opposite side with respect to the same articulated arm.

[33] In particular, in said orientation motion, the members composing the articulated arm are preferably operated in a combination of coordinated rotation and/or translation motions, in order to orient the at least one gripping member in a desired manner.

[34] The articulated arm preferably comprises a first member and a second member mutually articulated at least around an intermediate axis parallel to the orientation axis, at which the second member is articulated to at least one gripping member.

[35] Said orientation motion preferably involves the combination of rotational motions of the respective members of the articulated arm around the orientation axis and the intermediate axis.

[36] The articulated arm is preferably constrained to a height below the work surface at least around a constraint axis parallel to the orientation axis.

[37] Preferably, the articulated arm of the conveying device is constrained in a position between the overall dimensions of the bending unit and the overall dimensions of the feed station arranged upstream, serving the bending unit itself, to feed the bars.

[38] Said orientation motion preferably involves a further rotation motion of the first member around the constraint axis, to cause the gripping member to tip over.

[39] The articulation between the members of the articulated arm preferably produces plane motions of the respective members, but, alternatively or in addition, it can comprise joints, in particular ball joints or similar joints with rotation axes diverging with respect to the orientation axis, able instead to produce motions in three-dimensional space.

[40] According to a particular aspect, the conveying device can be constrained to the bending unit at one side or at the opposite side of the bending unit, with reference to the longitudinal direction. In any case, the conveying device is preferably constrained to the bending unit in such a way as to emerge from the operative plane following the aforementioned transfer motion.

[41] The articulated arm may comprise a spacer extending between the aforementioned first member and the second member and/or between the second member and the gripping member, for bringing the gripping member closer to an opposite side of the operative unit, so as to operate at said area. More precisely, this provision can bring the gripping member into an advantageous zone to carry out the gripping and handling operations, while leaving the articulated members behind, in a position such as not to interfere with its overall dimensions with the mechanical parts of the bending unit, therefore without negatively affecting, in the sense of a reduction, the minimum dimensions of the workpieces.

[42] Said first member of the articulated arm can be shaped like a double elbow. [43] The transfer device is preferably integrated with the bending unit, in particular pivoted below the work surface and substantially at the base thereof.

[44] At least one transfer motion is preferably transverse to the longitudinal direction.

[45] Preferably the apparatus comprises a further bending unit movable relative to the bending unit along the longitudinal direction.

[46] The gripping member can preferably be operated from the oriented configuration, which is, in particular, tipped over, where it is arranged above the work surface or the unloading surface, so as to disengage the number of bars with an at least partially lifting motion respectively from the work surface or from the unloading surface.

[47] The apparatus may comprise at least one further transfer device configured to cooperate with said transfer device in order to better support the relatively long rods. This additional device is preferably aligned with the other conveying device along the longitudinal direction.

[48] According to a particular aspect, the apparatus may comprise a plurality of transfer devices movable along the longitudinal direction, so as to make full use of the entire longitudinal extension of the apparatus, in particular of the unloading station, for unloading the bars or for correspondingly moving the bending heads.

[49] According to a particular aspect, the conveying device may comprise at least one further gripping member, carried by a further articulated member, preferably independently movable.

[50] The gripping member can preferably comprise a pair of jaws, at least one of which is movable with respect to the other between the open configuration and the closed configuration. At least one of them may internally comprise a recess and an end protruding portion, so that in the closed configuration preferably a single bar is clamped by the protruding portion and the remaining bars are instead received by the recess.

[51] The gripping member of the transfer device and the gripping portion of the bending head preferably have a section profile at least partially conjugated in order to improve gripping, involving a shape grip as well as friction grip.

[52] The apparatus preferably comprises a magazine having at least one containment seat for the bending head, positioned for example in an area adjacent to the bending unit. The transfer device can be usefully movable in said replacement motion also from the second position to a third position in which the gripping member is arranged at the magazine for releasing the bending head in said containment seat.

[53] Preferably the magazine comprises a plurality of containment seats for as many spare bending heads, arranged in succession along one direction, the transfer device being movable, as for example stated above, along said direction for collecting or unloading the spare bending head. [54] In the event that the same transfer device operates both the handling of the bars from and/or to the bending unit and of the bending heads, then advantageously the same activation can be used to operate the transfer device in motion along the longitudinal direction, in which the magazine of said tools can be developed, to carry out both operations.

[55] Preferably the magazine extends parallel to the longitudinal direction, interposed between the feeding station and the bending unit.

[56] The containment seats of the tool magazine are preferably arranged on a plane, for example horizontal or inclined, and interposed in succession on one or more rows, between a bar storage and/or feeding station and the at least one bending unit.

[57] Said gripping portion is preferably made by a handle projecting transversely from the mandrel.

[58] The gripping portion preferably has at least one recess configured to be engaged by the gripping member. Preferably the gripping portion has a pair of recesses separated by a rib shaped to be retained by the gripping member in the closing configuration.

[59] The bending unit preferably comprises a gripping housing for housing the gripping portion, when the bending head is engaged on the bending unit. The gripping housing is preferably shaped in such a way that the gripping portion is under the work surface when the bending head is engaged on the bending unit.

[60] The gripping housing can be selectively orientable with respect to the bending axis according to a collecting orientation, at which the gripping portion is intercepted and then retained by the gripping member in the first position.

[61] The method for bending metal bars according to the invention provides for arranging a bending unit equipped with a bending head and a transfer unit equipped with an articulated arm and a gripping member, articulated to the articulated arm.

[62] The method involves carrying out a bending cycle of a number of bars on the bending unit and then unloading the bent bars therefrom.

[63] The method then provides for grasping a gripping portion of the bending head with the gripping member of the transfer device and operating the transfer device in a substitution motion to draw out the bending head from the bending unit and transfer it to a magazine associated with the bending unit.

[64] Subsequently, the gripping device is activated to release the bending head in an empty station of the magazine.

[65] The transfer device is moved relative to the magazine to reach a station in the magazine where a spare bending head is positioned.

[66] The gripping member provides for gripping the respective gripping portion of the spare bending head. [67] The transfer device is moved to collect from the magazine, transfer and engage the spare bending head in the bending unit.

[68] Preferably the method further provides for actuating the same transfer unit in a transfer motion to grip the bars and load them onto the bending unit and/or to unload the bent bars from the bending unit.

Description of drawings

[69] The details of the invention will become more evident from the detailed description of a preferred embodiment of the apparatus for bending bars, illustrated by way of example in the accompanying drawings, in which: figures 1 - 8 respectively show a perspective view of a portion of the apparatus according to the invention in successive operating steps;

Figure 9 shows a perspective view of a detail of the apparatus according to the invention; Figures 10 and 10a respectively show a side view of a further detail of the same apparatus, in an operative step of gripping bars and gripping a bending head;

Figure 11 shows a perspective view of the apparatus according to the invention;

Figure 12 shows a plan view of a portion of the apparatus illustrated in figure 11 , in an operational step;

Figures 13, 14 and 15 show a perspective view of a portion of the same apparatus in successive operational steps for handling the bars.

Description of embodiments of the invention

[70] With particular reference to these figures, the reference sign 1 indicates as a whole the apparatus for bending bars 2, in particular iron rods for reinforced concrete (see in particular figures 13, 14 and 15).

[71] The apparatus according to the invention allows bending of a plurality of bars 2 at each bending cycle, but can also be used to bend one bar 2 at a time.

[72] The apparatus 1 may comprise a feed station 3, at which the bars 2 arrive, arranged in a longitudinal direction A, intended to be bent (see Figure 11).

[73] Apparatus 1 comprises a bending unit 4, formed by at least one bending unit 41 , preferably a pair of bending units 41 , and a transfer unit 5, associated with the bending unit 4 to carry out replacement and possibly transfer operations, as described below.

[74] Preferably the bending unit 41 is made in the form of a bending bench.

[75] The apparatus 1 can comprise an unloading station 6 of the bent bars 2 (see in particular Figure 11 ), preferably arranged downstream of the bending unit 4, for example beside, according to a direction to said longitudinal direction A, the bending assembly 4.

[76] The apparatus 1 can also advantageously comprise a storage magazine 8 for the bending tools used by the bending unit 4, as described in detail below.

[77] The feeding station 3 preferably comprises at least one transversal positioning device 31 , for example of the catenary type, to allow the fed bars 2 to be moved transversely.

[78] Preferably the feeding station 3 comprises a plurality of transversal positioning devices 31 , arranged in succession, for example uniformly distributed, along the longitudinal direction A, to allow an optimal transversal movement for bars 2 of any length and bring them to an area where the transfer assembly 5 or similar means can collect them.

[79] In the apparatus illustrated in Figure 11 , the bending assembly 4 comprises a pair of bending units 41 for manufacturing, in particular, products shaped at one or both ends, but according to the invention, apparatuses may be provided in which there is only one or a different number of bending units 41 .

[80] In particular, at least one provided bending unit 41 is movable parallel to the longitudinal direction A along which the bars 2, one or more, can be fed to be bent (see Figure 12). For example, the bending unit 41 can slide on guide rails 4a (see Figure 1 ).

[81] More precisely, in the case of a pair of bending units 41 , they are preferably aligned and movable with a relative translational motion parallel to the longitudinal direction A in order to position the bars 2 to be machined between them. In other words, at least one bending unit 41 is movable with said translation motion along the guide rails 4a (see Figure 1 ), so as to adapt its position according to the length of the bars 2 to be processed and the geometry to form.

[82] Each bending unit 41 operates on a work surface a, on which the bars 2 can be placed and bent by the bending members.

[83] The bending units 41 are preferably arranged downstream, in particular beside, of the feeding station 3 and each one carries a bending head 40.

[84] The bending head 40 carries said bending members and is interchangeable, in the sense that it can be replaced for example to satisfy different production requirements.

[85] Advantageously it can be of any type. For example, the bending head 40 can include a central bending mandrel 42 as the mandrel and an eccentric bending pin 43 (see for example Figure 9).

[86] Alternatively, for example, a different bending head can be mounted on the bending unit 41 , comprising as mandrel a double mandrel 45 crossed by a seat for the bars 2 and possibly also the same eccentric bending pin 43 (see Figure 12).

[87] In any case, the central mandrel 42 or the double mandrel 45 define a central bending axis B, around which, when the bending head 40 is engaged on the bending unit 41 , the eccentric pin 43 is rotated to operate the bending of the interposed bars.

[88] Between the bending members, central mandrel 42 and eccentric pin 43 or between double mandrel 45 and eccentric pin 43, an insertion seat 46 for the bars 2 is defined in a known way, at which, when the bars 2 are correctly housed therein, the eccentric pin 43 acts in cooperation with the respective mandrel, rotating about the central bending axis B and thus causing the desired bending of a respective portion of the bars 2 themselves (see in particular Figure 12).

[89] The bending head 40 cooperates, preferably, with an abutment 44 mounted, for example, on the bending unit 41 , capable of blocking the piece in the machining step in a suitable way (see for example Figure 1 ).

[90] In practice, the eccentric pin 43 is configured to bend a number of bars 2 which are inserted inside the insertion seat 46, rotating around the central mandrel 42 or the double mandrel 45, being movable in a part of the work surface a, opposing the abutment 44.

[91] The abutment 44 can in turn be configured to hold respective portions of said number of bars 2 in the bending phase operated by the eccentric pin 43. These portions, in particular, are distal to those intended to be engaged by the eccentric pin 43 in the same bending step.

[92] The bending head 40 also forms a gripping portion 47 intended to be gripped by the transfer assembly 5 to replace the bending members on the bending unit 41.

[93] In other words, the gripping portion 47 acts as a handle for the transfer assembly 5, so that the latter can draw out the bending head 40 from the bending unit 41 and replace it with a different equipment, suitable for the cycle of bending to be made.

[94] The gripping portion 47 is preferably made in the shape of a handle projecting transversely to the bending axis B. Said portion preferably develops in a transversal direction, for example perpendicular, to the bending axis B.

[95] Alternatively, the gripping portion 47 can protrude from the central mandrel 42 or from the double mandrel 45 along a respective central axis or along an axis substantially parallel thereto, or shaped by the same eccentric pin 43.

[96] According to a particular, non-limiting embodiment, shown in the figures, the bending head 40 can comprise a base 48, for example a flat base, on which the central mandrel 42 or the double mandrel 45 is mounted. A support arm 48a on which the eccentric pin 43 is mounted (see Figure 9) extends, preferably in a radial direction, from the base 48 with respect to the central bending axis B.

[97] The gripping portion 47 can develop from the same base 48, preferably in an opposite way to the support arm 48a. According to a possible alternative variant, the gripping portion 47 can be made on the same support arm 48a.

[98] The gripping portion 47 preferably has a shaped profile, such as to allow the gripping by the transfer assembly 5, in particular of a respective gripping member, as described below.

[99] For example, the gripping portion 47 can be shaped so as to form at least one recess 47a, preferably a pair of recesses 47a, opposite with respect to a central crest. The recesses 47a then define a rib 47b therebetween. [100] Preferably the recesses 47a develop parallelly along the gripping portion 47, so that the rib 47b forms a dividing wall therebetween. The recesses 47a are used to house the gripping member of the transfer unit 5, to allow gripping of the bending head 40. More precisely, according to a particular aspect, the gripping member of the transfer assembly can clamp said rib 47b.

[101] Advantageously, the recesses 47a can form, in section, a hooking profile 47c mating with the sectional profile of said gripping member, as described below, so as to guarantee a firm and secure grip.

[102] More generally, the gripping portion 47 can shape a different hooking profile 47c, in particular different from that illustrated, but capable of facilitating the grip, providing a form component in addition to the friction component, to grip and retain the bending head 40.

[103] The bending head 40 preferably comprises a shaft 49, protruding in an axial direction to the central mandrel 42, coinciding in use with the bending axis B (see Figures 3 and 10a). The shaft 49, which protrudes from one side of the head which, in operation, abuts on the bending unit 41 , is to be keyed onto the bending unit 41 so as to be rotated and thus allow the bending of the bars 2 around the bending axis B.

[104] The bending unit 41 , in turn, comprises a seat 410, for housing the bending head 40, so that respective portions other than the bending tools can be housed under the work surface a so as not to interfere with the bending operations that can be carried out thereon (see Figures 3 and 4).

[105] In particular, the seat 410 may comprise a central housing 411 into which the shaft 49 and possibly the support base 48 of the central mandrel 42 or of the double mandrel 45 can be inserted, if provided. The seat 410 itself may also comprise, for example in continuity with the central housing 411 , an eccentric housing 412 for the gripping portion 47. Finally, the seat 410 may comprise, for example in continuity with the central housing 411 , a second eccentric housing 413 for receiving the support 48a of the eccentric pin 43 (see Figures 3 and 4).

[106] Advantageously, the eccentric housing 412 can be made in the form of a cavity obtained under the work surface a, in such a way that, in operation, the gripping portion 47 is mounted flush or underneath the work surface a, so as not to interfere with the bending operations.

[107] In particular, the eccentric housing 412 and the gripping portion 47 can be shaped such that when the latter is mounted on the bending unit 41 , the recesses 47a are positioned under the work surface a to receive respective operative portions of the gripping member of the transfer assembly 5, and thus allow the operations of drawing out the bending head 40.

[108] Preferably the eccentric housing 412 is made in the form of a cavity, in particular a channel, which develops radially from the central housing 411 of the seat 410.

[109] The eccentric housing 412 can form a cavity of greater size than the gripping portion 47 to allow insertion of said gripping member. Alternatively, the central housing 412 may have a conformation substantially commensurate with the gripping portion 47, so as to avoid discontinuity on the work surface a. In this case, pusher means are preferably provided, configured to push the bending head 40, such that it emerges from the work surface a to be gripped there by the gripping member.

[110] The transfer assembly 5 is associated with the bending unit 41 , preferably arranged in an intermediate position between the feeding station 3 and the unloading station 6.

[111] The transfer assembly 5 comprises at least one transfer device 50 preferably mounted integral, therefore integrated, with the bending unit 41. For example, the transfer device 50 can be constrained, in particular pivoted, on the inner side (see Figure 12) or outside with respect to the longitudinal direction A or inside the bending unit 41 (see Figure 11 ).

[112] The internal side is the side of the bending unit 41 in which the abutment 44 is fixed, while the external side is the opposite side, in which the eccentric pin 43 operates, to bend the number of bars 2 inserted in the insertion seat 46.

[113] Preferably, the transfer assembly 5 comprises a transfer device 50 serving each bending unit 41.

[114] Preferably the transfer device 50 of the transfer assembly 5 is configured to handle both the bending heads 40, for their replacement, and the bars 2 to be machined or already bent 2a.

[115] Advantageously, the apparatus 1 may comprise at least one further transfer device 50’, dissociated from the bending units 41 , for example intermediate, fixed or independently movable between the bending units 41 themselves, otherwise preferably completely similar to each transfer device 50 (see Figure 11). The further transfer device 50’ is preferably operative only during the steps of handling, in particular of loading and unloading, of the bars 2, as described thereafter. In particular, such a device 50’ may not play any role during the steps of changing tools.

[116] The transfer devices 50, 50’ can then be operative in cooperation along the entire longitudinal development of the apparatus 1 , thus allowing, in particular, handling, transfer and unloading in sequence, in addition to the bending heads 40, of bent bars 2a of shorter length than the total length of the apparatus 1 on an unloading plane at the unloading station 6 (see Figure 12).

[117] Each transfer device 50, 50’ preferably comprises an articulated arm 51 and at least one gripping member 52 carried at the opposite end of the articulated arm 51 (see in particular Figure 6). In particular, the further transfer device 50' can be shaped in the same or different way from the transfer device 50 and have different articulations. In any case, the movements of the gripping member 52 carried thereby are preferably synchronized with those of the other gripping members.

[118] The articulated arm 51 is mounted under the work surface a, preferably articulated, in particular pivoted, at the base of the bending unit 41 underneath the work surface a.

[119] More precisely, the articulated arm 51 preferably comprises at least a first member 51a and a second member 51 b, mutually articulated at an intermediate articulation axis 53 (see Figure 6).

[120] The first member 51a and the second member 51 b of the articulated arm 51 can be articulated by the interposition of a spacer member 53a mounted on the intermediate axis

53. Alternatively, the spacer 53a can be mounted between the second member 51 b and the gripping member 52 or partly in one and partly in the other.

[121] The articulated arm 51 , preferably by means of the same first member 51a, can also be articulated under the work surface a of the bending unit 41 at a respective constraint axis

54. Alternatively, the articulated arm 51 can comprise a greater number of articulated members, also provided with different, in particular further, degrees of freedom.

[122] The articulated arm 51 is in turn articulated to the gripping member 52 at an orientation axis 55, in particular at the end (see Figure 6).

[123] In particular, the intermediate axis 53, the aforementioned constraint axis 54 and the orientation axis 55 are preferably parallel to said longitudinal direction A.

[124] The transfer device 50 is movable, in particular tiltable, with a replacement motion for the replacement of the bending head 40.

[125] The transfer device 50 can also be movable in a transfer motion for handling the bars 2, 2a from and/or to the bending unit 41 .

[126] In particular, in the replacement motion, the transfer device 50 is movable between a first position 50a, at which the gripping member 52 is oriented towards the work surface a of the bending unit 41 and gripping the gripping portion 47 of the bending head 40 mounted on the bending unit 41 (see for example in Figure 1 a first gripping step), and a second position 50b, in which the gripping member 52 is raised from the work surface, so drawing out the bending head 40 from the bending unit 41 (see Figure 2).

[127] The transfer device 50 can be usefully movable towards and from a third position 50c at the magazine 8, to release a bending head 40 and/or to grip, in a different position in the magazine 8, a spare bending head 40', for example with different characteristics, to satisfy a production cycle different from the current one (see Figures 2, 3, 4 and 5 respectively).

[128] The transfer device 50 can be movably operated in the aforementioned transfer motion by means of a respective motor assembly.

[129] Furthermore, the transfer device 50 can be movable parallel to the longitudinal direction A to position the gripping member 52 in a suitable fashion with respect to the magazine 8, so as to reach respective seats for the bending head 40 to be replaced and for the spare bending head 40'. The transfer device 50, in the event that it is constrained to the bending unit 41 , can use, for example, the mobility of the bending unit 41 itself on the rails 4a.

[130] The same transfer device 50 can advantageously carry out both the change of the bending tools on the bending unit 41 and the feeding of the bars 2 on the bending unit 41 and the release of the shaped bars 2a in the unloading station 6 (see Figures 13 - 15).

[131] More precisely, the transfer device 50 can be further operated in a movable, preferably tilting, fashion, according to said transfer motion, between the feeding station 3, the bending assembly 4 and the unloading station 6, respectively to collect the bars 2 to be bent, to insert them on the bending unit 41 and to unload the shaped bars 2a.

[132] In the particular handling of the bars 2, the transfer assembly 5 preferably allows to carry out a first transfer and a second transfer, in an overall path between respectively feeding station 3 and unloading station 6, which are opposite to the bending assembly 4 placed in an intermediate position therebetween. The bending assembly 4, therefore, may represent a crossing station in this sense.

[133] To allow this crossing, the transfer assembly 5, which is located at the intermediate bending assembly 4, advantageously allows collection of the number of bars 2 according to any orientation and release of the same number of bars 2 on a respective releasing, operative or unloading plane, in an ordered configuration, in particular in abutment and, in the case of a plurality of bars 2 or bent bars 2a, stacked, that is superimposed one on the other. In particular, according to the described path, a desired number of bars 2 can be both released, for subsequent bending, and collected at the insertion seat 46. To achieve this effect, the gripping member 52, of each transfer device 50, 50' involved, can be oriented following an orientation movement, in particular with an overturning, indifferently in the first or in the second transfer section mentioned, gripping member being empty or when holding the number of bars 2, to release the bars 2.

[134] In particular, the gripping member 52 may be overturned, following the aforementioned orientation motion, first on one side and then on the opposite side with respect to the articulated arm 51 to which it is articulated, as described in detail below.

[135] Among the consequences of this circumstance, in particular, the number of bars 2, 2a can for example cross the bending assembly 4 and be released with an open motion of the gripping member 52.

[136] Furthermore, the gripping member 52 can be oriented, following said overturning, with a respective passage opening 7 downwardly facing in operation, in particular towards the releasing plane. In other words, thanks to said overturning, the gripping member 52 can result arranged above, in the overturned configuration, with respect to the passage opening 7 (see Figure 10). [137] This circumstance allows for example to accompany the number of bars 2, 2a on the unloading surface in the unloading station 6, abutting against it, and to separate from the same unloading plane, with a lifting motion of the gripping member 52.

[138] More precisely, the articulated arm 51 is preferably shaped so as to overturn the gripping member 52, by means of corresponding rotations around the aforementioned joints, for example around the intermediate axis 53 and the orientation axis 55. Consequently, for example, a number of bars 2 can be collected from the feeding station 3 (see Figure 13) and transferred to the bending unit 41 (see Figure 14), through the operation of the articulated arm 51.

[139] Thanks to said overturning, in particular, the transfer device 50 is able to release the number of bars 2 from above, inserting them into the insertion seat 46.

[140] The same articulated arm 51 is also preferably able to collect and transfer the bars 2 in said path, once the bars are bent 2a, between the bending unit 41 and the unloading station 6, in particular without causing any slip in the number of bars 2 gripped, avoiding misalignments and rotations, especially if the bars are already bent. The articulated arm 51 , in particular, carries the gripping member 52 in a first configuration at the feeding station 3, while it can carry the same gripping member 52 overturned at the bending unit 41. It is possible to provide for this overturning, alternatively, in the second transfer, between the bending unit 41 and the unloading station 6.

[141] In particular, the kinematic mechanism of the articulated arm 51 is preferably configured so that the member articulated to the gripping member 52 can tilt above the bending head 40, in particular, with a roto-translation motion. Thanks to the particular shape of the articulated arm 51 , the transfer device 50, 50' can therefore replace the bending head and/or transfer the bars 2, so that they can overcome, crossing it from above, the space represented by the articulated arm 51 , constrained under the work surface a (see in particular Figures 1 to 4).

[142] Likewise, the transfer device 50 can unload the bent bars 2a, without altering their orientation and ordered arrangement. In fact, thanks to the particular kinematics of the articulated arm 51 which carries the gripping member 52, the bent bars 2a are accompanied to the unloading station 6 and released from above, bringing the gripping member 52 into an open configuration. This circumstance allows, in particular, ordered stacking, that is an ordered superimposition of the bent bars 2a.

[143] Release "from above" means that the passage opening 7 of the gripping member 52 is downwardly facing in the release condition.

[144] Furthermore, it should be noted that the particular kinematic mechanism of the articulated arm 51 can allow the transfer device 50, 50' to cooperate with the bending units 41 in the bending steps of the bars 2, orienting and rotating in an appropriate manner the number of retained bars 2, 2a.

[145] The kinematic configuration of the described solution for the transfer device 50, 50' is to be considered as preferred, but not limiting. In particular, it is possible to provide that the articulated arm 51 includes a different number of members and that the constraints between them can be different, thus giving rise to different relative motions, rotational and/or translational, according to axes oriented in a different way.

[146] The gripping member 52 is preferably of the jaw type (see for example Figure 6).

[147] It preferably comprises a pair of jaws 52a, at least one of which is movable relative to the other in a closing and opening motion, between an open configuration and a closed configuration. More precisely, in the open configuration, the jaws 52a are spaced apart from each other to introduce or release the gripping portion 47 or, possibly, the bars 2, 2a or for the insertion of the same, through the opening of passage 7, while in the closed configuration the jaws 52a are mutually approached, to retain the gripping portion 47 and possibly enclose and intercept a number of bars 2, 2a (see figures 10 and 10a).

[148] In particular, the sectional profile of the jaws 52a can be shaped to match the gripping portion 47.

[149] In particular, but not exclusively, for handling the bars 2, 2a, the jaws 52a can be shaped in such a way as to define between them a receiving space 56 which in the closed configuration is closed, making it possible to hold, in particular to clamp, said number of bars 2, 2a, while in the open configuration it is opened through the passage opening 7.

[150] In particular, at least one jaw 52a can shape internally a respective recess 57 and an inwardly projecting end portion 58.

[151] The recess 57, in particular, can have at least partially a flat wall, intended to face parallelly to a respective flat wall of the opposite recess 57, so that the bars 2, 2a retained in the receiving space 56 in the closed configuration are arranged side by side on a same level.

[152] On the flat wall of at least one recess 57 a layer 59 of an elastic material, for example rubber, can be applied to maintain the positioning of the handled objects, for example of the bars 2, 2a during the overturning and transfer steps of the bars 2, 2a.

[153] Furthermore, the at least one protrusion 58 can cooperate with the at least one recess 57 to hold the gripping portion 47 or possibly the intercepted bars 2 in the closed configuration.

[154] Advantageously, the at least one protrusion 58 or the pair of protrusions 58 are configured to clamp the gripping portion 47 or, in the case of manipulation of the bars, preferably only the end bar 2, 2a, among those intercepted, so as to close the receiving space 56, while the remaining bars 2, 2a can be held in an orderly manner within the receiving space 56 (see Figure 10). [155] More precisely, the protrusions 58 can be configured to clamp the walls of the rib 47b of the bending head 40 (see Figure 10a).

[156] The unloading station 6 can be defined in the space, in particular on the ground, beside the bending assembly 4, to receive the bent bars 2a, already subjected to a bending cycle by the at least one bending unit 41 (see Figure 11 ).

[157] The space on the ground can further be equipped with containment devices 60, preferably movable, for example made by racks, conveyor belts, carriages or chain means, to allow the unloading station 6 to be easily freed (see Figure 11 ).

[158] Further characteristics and/or embodiments of the transfer device 50, 50' are described in the Italian patent application no. 102021000011660 filed on 5 June 2021 in the name of the Applicant, which is understood to be incorporated into this application for this purpose.

[159] The operation of the apparatus according to the invention, a particular example of which is given below, can be understood from the preceding description.

[160] In an initial preparation phase or between one bending cycle and another, it may be necessary to adapt the equipment of the bending unit 4 to the production requirements. For example, it may be necessary to change the bending head 40 mounted on the bending unit 41 with a spare bending head 40', which is in the magazine 8.

[161] In this case, the bending head 40 is possibly rotated in the aforementioned collecting orientation, suitable for handling by the gripping member 52. For example, according to this orientation, the gripping portion 47 of the bending head 40 can extend interposed between the bending axis B and the abutment member 44.

[162] In a first gripping step, the transfer device 50 associated with the bending unit 41 is moved in the replacement motion to insert the gripping member 52 in the recesses 47a and clamp the rib 47b (see figure 1 ), in the first position 50a. Alternatively, pusher means can push the bending head 40 into a condition that emerges from the work surface a, so that the gripping member 52 can grip the gripping portion 47 thereon.

[163] The transfer device 50 is then actuated in the second raised position 50b to draw out the bending head 40, preferably retained also thanks to the hooking profile 47c, by lifting it from the work surface a (see Figure 2). In particular, in this step the gripping member 52 is moved according to a lifting, preferably translational, motion, so as to come out from the recesses 47a, if provided.

[164] Subsequently, the transfer device 50 is actuated in the third position 50c to bring the bending head 40 to the magazine 8 and position it in a respective deposit seat (see Figures 3 and 4).

[165] The transfer device 50, possibly after having been brought into a condition of noninterference, for the subsequent motion, with other parts of the apparatus, is then moved in a direction preferably parallel to the longitudinal direction A to reach and collect the spare bending head 40' deposited in magazine 8 (see Figure 5). Preferably, the positioning of the transfer device 50 is achieved integrally with the bending unit 41 , by making the bending unit 41 slide on the rails 4a.

[166] The transfer device 50 is then moved to draw out the spare bending head 40' from the magazine 8, which can be, for example, flat or inclined, on one or more rows.

[167] The transfer device 50 is then moved in the return stroke towards the bending unit 41 to insert the spare bending head 40' in the respective seat 410. This insertion is performed by orienting the spare bending head 40' from the current orientation with which it was collected from the magazine 8 to the collection orientation to be inserted into the eccentric housing 412 (see Figures 6, 7 and 8). This current orientation may eventually coincide with the collection orientation on the bending unit 41.

[168] It should be noted that it is possible to precisely control the movement of the degrees of freedom of the transfer device 50, in particular of the articulated members 51a, 51 b, so as to guarantee the precise positioning of the bending head 40 in the collection orientation and thus allow both the correct collection and the correct insertion of the spare bending head 40' on the bending unit 41 .

[169] When the replacement operations are completed, a new bending cycle can be started.

[170] Individual bars or, preferably, a plurality of bars 2 to be bent are fed to the feeding station 3.

[171] The transversal positioning devices 31 , with a series of alternating movements, move the bundle of bars 2 fed to the feeding station 3 until the bars 2 are arranged neatly aligned in a single layer.

[172] The gripping member 52, preferably of at least one pair of transfer devices 50, 50', can be actuated in the transfer motion, approached at a predefined transverse distance to the feeding station 3 and brought into the open configuration, so as to intercept a predefined number of bars 2. This predefined transverse distance substantially corresponds to the transverse dimension of the number of bars 2 to be collected. In particular, if the bars 2 are placed side by side due to the action previously performed by the transversal positioning devices 31 , the number of intercepted bars 2 is perfectly equal to that expected (see Figure 13).

[173] The gripping member 52 is then operated in the closed configuration to clamp the number of bars 2 to be subjected to the bending cycle.

[174] Subsequently, the transfer devices 50, 50' are actuated in a coordinated manner in the transfer motion from the feeding station 3 to the bending assembly 4, at the same time moving the gripping member 52 in the orientation motion. Preferably the gripping member 52 is overturned at the same time and, consequently, the bars 2 are correctly intercepted. The orientation motion, in particular overturning, of the gripping member 52 can be performed, alternatively, in the subsequent transfer, between the bending assembly 4 and the unloading station 6 or when it is empty, in the absence of bars 2 retained.

[175] The at least one bending assembly 41 then performs a bending cycle, advantageously with the cooperation of the conveying devices 50, 50' to obtain bent bars 2a.

[176] In particular, the eccentric pin 43 can be rotated around the bending axis B to bend a respective portion of the bars 2 (see for example Figure 12).

[177] The bending assembly 4 can carry out different bending cycles on the bars 2, thanks to the cooperation with the transfer assembly 5, so as to make flat or three-dimensional bent bars 2a. More precisely, the particular articulation of the articulated arm 51 carrying the gripping member 52 can allow the bars 2 to be oriented, positioned and retained, to create both flat and three-dimensional rebars.

[178] When the bending cycle of the bars 2 is concluded, the transfer unit 5 is preferably activated in the unloading motion to transfer the bent bars 2a in an orderly manner from the bending assembly 4 to the unloading station 6.

[179] The apparatus for bending bars according to the invention therefore achieves the aim of allowing the optimal handling of the bending head and possibly of the bars, in particular by minimizing the space occupied and optimizing production efficiency.

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

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

Claims

Claims An apparatus for bending bars, in particular metal bars, comprising at least one bending unit (41 ) adapted to receive at least one said bar (2) on a work surface (a) according to a longitudinal direction (A), and a bending head (40) which can be engaged on said bending unit (41), at a bending axis (B), said bending head (40) comprising a bending mandrel (42, 45) and an eccentric pin (43), rotatable on said work surface (a) around said bending axis (B), to bend said bar (2) around said mandrel (42, 45), and a conveying device (50) comprising an articulated arm (51 ) constrained to a height below said work surface (a) and a gripping member (52) articulated to said articulated arm (51) at an orientation axis (55), said gripping member (52) being movable between an open configuration for releasing and a closed configuration for holding, characterized in that said bending head (40) comprises a gripping portion (47) configured to be held by said gripping member (52) arranged in said closed configuration and in that said transfer device (50) is movable with a replacement motion between a first position (50a) in which said gripping member (52) is arranged in a closed configuration at said bending head (40) mounted on said bending unit (41 ), to hold said gripping portion (47), and a second raised position (50b), in which said bending head (40) held by said gripping member (52) is drawn out from said work surface (a). The apparatus of claim 1 , wherein it comprises a magazine (8) having at least one containment seat (80) for said bending head (40), said transfer device (50) being movable in said replacement motion from said second position (50b) to a third position (50c) in which said gripping member (52) is arranged at said magazine (8) to release said bending head (40) in said containment seat (80). The apparatus of claim 2, wherein said magazine (8) comprises a plurality of containment seats (80) for as many spare bending heads (40'), said transfer device (50) being movable to take or insert said spare bending head (40'). An apparatus of any one of claims 2 or 3, wherein said magazine (8) extends parallel to said longitudinal direction (A), being interposed between said feeding station (3) and said bending unit (41 ). An apparatus of any one of the preceding claims, wherein said gripping portion (47) is made by means of a handle projecting transversely from said mandrel (42, 45). The apparatus of claim 5, wherein said gripping portion (47) has at least one recess (47a) configured to be engaged by said gripping member (52). The apparatus of claim 6, wherein said gripping portion (47) comprises a pair of recesses (47a) separated by a rib (47b) shaped to be held by said gripping member (52) in said closed configuration. An apparatus of any one of the preceding claims, wherein said gripping portion (47) is obtained at least partially from a portion of said mandrel (42, 45), opposite to said eccentric pin (43). An apparatus of any one of the preceding claims, wherein said bending assembly (41) comprises an eccentric housing (412) for housing said gripping portion (47), when said bending head (40) is engaged on said bending unit (41), shaped so that said gripping portion (47) is substantially underneath said work surface (a) when said bending head (40) is engaged on said bending unit (41 ). The apparatus of claim 9, wherein said eccentric housing (412) is selectively orientable with respect to said bending axis (B) according to a collecting orientation, at which said gripping portion (47) is oriented to be held by said gripping member (52) in said first position (50a). An apparatus of any one of the preceding claims, wherein said gripping member (52) is a jaw member (52a), configured to engage said gripping portion (47). An apparatus of any one of the preceding claims, wherein said gripping member (52) and said gripping portion (47) have an at least partially conjugate sectional profile. An apparatus of any one of the preceding claims, wherein said transfer device (50) is configured to hold one or more said bars (2) in said closed configuration, being also movable with a transfer motion to transfer said retained bars (2) from and/or to said bending unit (41 ). An apparatus of any one of the preceding claims, wherein said articulated arm (51 ) of said transfer device (50) is constrained in a position between the dimensions of said bending unit (41 ) and the dimensions of a feeding station (3) arranged upstream, serving said bending unit (41 ) to feed said bars (2) therein. A method for bending bars, in particular metal bars, comprising the steps of a. arranging a bending unit (41 ) equipped with a bending head (40) and at least one transfer device (50) equipped with an articulated arm (51) and a gripping member (52), articulated to said articulated arm (51 ); b. carrying out a bending cycle of a number of bars (2) on said bending unit (41) and unloading said number of bent bars (2a) from said bending unit (41 ); c. grasping with said gripping member (52) a gripping portion (47) of said bending head (40); d. operating said transfer device (50) in a replacement motion to draw out said bending head (40) from said bending unit (41 ) and transferring it to a magazine (8) associated with said bending unit (41); e. operating said gripping member (52) to release said bending head (40) in an empty position of said magazine (8); f. moving said transfer device (50) relative to said magazine (8) to reach a position of magazine (8) where a spare bending head (40') is placed; g. grasping said respective gripping portion (47) of said spare bending head (40') with said gripping member (52); h. moving said conveying device (50) to take from said magazine (8) said spare bending head (40'), transfer and engage it into said bending unit (41 ). The method of claim 15, wherein it provides for operating said transfer device (50) in a transfer motion to grasp said bars (2) and load them onto said bending unit (41 ) and/or to unload said bent bars (2a) from said bending unit (41 ).