Machine for working bars and corresponding method

Abstract

Machine (10) for working bars comprising a fixed work plane (12) with which there are associated, in sequence along an axis of feed (X), a bending assembly (19) and a curving unit (25). Said machine (10) also comprises a gripper device (16) configured to move at least one bar (100) along said axis of feed (X) in a manner that is operationally coordinated with the operation of the bending assembly (19) and / or of said curving unit (25).

Description

[0001] “MACHINE FOR WORKING BARS AND CORRESPONDING METHOD”

[0002] FIELD OF THE INVENTION

[0003] The present invention concerns a machine for working bars suitable to bend and / or curve bars or, in general, oblong shaped products such as wire rods, round or square section bars, with a circular, polygonal or flat shaped cross-section.

[0004] By way of example only, the aforementioned machine can bend and / or curve wire rods, fed in the form of a bar or in the form of a coil, or coming from a straight bar cutting center. BACKGROUND OF THE INVENTION

[0005] Machines for working bars are known, suitable to bend and / or curve bars such as wire rods, round or square section bars, with a circular, polygonal or flat shaped cross-section.

[0006] These machines are normally provided with at least two support trolleys reciprocally mobile along an axis of movement and each provided with a work plane on which at least one curving unit and at least a first bending unit are installed. Often, these machines can also have a second and a third bending unit, which are capable of bending the bar with different bending radii.

[0007] A drawback of these machines is that the bar, while its ends are being worked, can undergo unwanted flexion in the central zone, even if suitable support elements are provided.

[0008] Another drawback of these machines is that the operations for curving the bar occur symmetrically, starting from its ends, whereby defects can arise caused by the different towing capacity of the curving units during the work. Another drawback of these machines is that the different bending operations, possibly with different radii, and curving operations take place by moving the bar itself and aligning it with the direction of work of the unit concerned. This can cause a waste of time and slowness in the production of finished products, as well as possible positioning errors that can cause non-compliant parts. Another drawback of these machines is that the presence of mobile support trolleys, together with the movement of aligning the bar, presupposes a high number of moving masses and therefore a zone that is highly dangerous for the operators in charge of controlling the work. There is therefore the need to perfect a machine for working bars and corresponding working method that can overcome at least one of the disadvantages of the state of the art.

[0009] One purpose of the present invention, which corresponds to the technical problem to be solved, is to simplify the construction of traditional machines for working bars which are capable of performing both bending operations with different radii and also bending operations on one or more bars at a time.

[0010] Another purpose of the present invention is to provide a machine for working bars and to perfect a method capable of performing a series of bends and curves on one or more bars at a time in a simple, rapid and highly productive manner.

[0011] Another purpose of the present invention is to provide a machine for working bars capable of reducing non-compliant pieces which are caused by the numerous movements and reciprocal positionings between bar and work units that characterize known machines. The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

[0012] SUMMARY OF THE INVENTION

[0013] The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

[0014] In accordance with the above purposes and to resolve the technical problem described above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a machine for working bars according to the present invention, conceived to perform both bending as well as curving operations on one or more metal bars at a time, comprises a fixed work plane with which there are associated, in sequence along an axis of feed, a bending assembly provided with at least two distinct bending units which can be selectively aligned with the axis of feed, and a single curving unit aligned with the axis of feed. The machine also comprises a gripper device configured to move at least one bar along the axis of feed in a manner that is operationally coordinated with the operation of the bending units and / or of the curving unit.

[0015] Doing so achieves at least the advantage of simplifying the machine’s construction and of performing bending and curving on one or more bars at a time in a simple, rapid and precise manner. The use of a gripper to advance the bar increases the precision of both the bending and also the curving because the bar, being clamped, does not twist around its axis. Furthermore, the machine is of the “self-centering” type, whereby the bar is moved only in the direction of feed, which is fixed, while the bending and curving units adapt their position or configuration as a function of the position of the bar and the specific work to be performed. This allows to increase the work accuracy and reduce non-compliant pieces.

[0016] In accordance with another aspect of the present invention, the bending assembly comprises a slide on which the at least two distinct bending units are mounted, wherein the slide is able to be positioned in a direction of alignment that is transverse to the axis of feed.

[0017] In accordance with another aspect of the present invention, each bending unit comprises its own contrast element with a different bending radius, and a bending element selectively rotatable around the corresponding contrast element to bend the bar around the latter.

[0018] In accordance with another aspect of the present invention, the single curving unit comprises two contrast rollers located in opposing positions to each other with respect to the axis of feed, and two distinct curving rollers. Advantageously, both curving rollers are able to be positioned with respect to the contrast rollers in order to exert a desired deformation / curvature on the bar.

[0019] In accordance with another aspect of the present invention, the gripper device is provided with gripping elements to hold the bar. The gripper device can also be provided with optional cutting elements to perform the head and / or tail cut of the bar.

[0020] In accordance with another aspect of the present invention, the machine comprises two distinct holding devices associated with the work plane along the axis of feed, respectively upstream and downstream of the bending assembly.

[0021] In accordance with another aspect of the present invention, each bending unit, the curving unit and the devices are able to be moved retracted with respect to the work plane.

[0022] In accordance with another aspect of the present invention, the gripper device is part of a movement assembly also comprising a guide which extends parallel to the axis of feed and to the work plane, and with which the gripper device is associated sliding. The guide is preferably facing, at the upper part, the work plane.

[0023] Some embodiments of the present invention concern a method for working bars comprising: a first advance step, in which at least one bar is held by a gripper device and, by means of the gripper device, is made to advance along an axis of feed toward a bending assembly provided with at least two distinct bending units; one or more bending steps, in which one of the bending units is positioned aligned with the axis of feed so as to perform a bend on the bar; a second advance step, in which by means of the gripper device the bar is made to advance along the axis of feed toward a single curving unit; a curving step, in which by means of the gripper device the bar is made to advance in a controlled manner through the curving unit and subsequently unloaded; wherein the gripper device moves the at least one bar in a manner that is operationally coordinated with the operation of the bending units and / or of the curving unit.

[0024] DESCRIPTION OF THE DRAWINGS

[0025] These and other aspects, characteristics and advantages of the present invention will become apparent from the following description of an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

[0026] - fig. 1 is a schematic top view of a machine for working bars according to the present invention;

[0027] - figs. 2-7, together with fig. 1 , show a possible operating sequence for working a bar in accordance with the work method according to the present invention. We must clarify that the phraseology and terminology used in the present description, as well as the figures in the attached drawings also in relation as to how described, have the sole function of better illustrating and explaining the present invention, their purpose being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims. To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications. DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

[0028] With reference to fig. 1, a machine 10 according to the present invention is configured to bend and curve one or more metal bars 100, in order to make brackets or other reinforcement shapes for the construction industry having a certain geometry, not shown in the drawings. The bars 100 have a predominantly elongated development.

[0029] For illustrative purposes only, the bars 100 can have a length comprised between about 1.5 m and about 24 m, in any case no shorter than about 0.5 m, and diameters comprised between about 10 mm up to about 40 mm. The machine 10 comprises a fixed structure 11 having a work plane 12, disposed substantially horizontal with respect to an installation surface of the machine 10. However, it is not excluded that the work plane 12 may also be inclined with respect to the installation surface, for example to facilitate the evacuation by gravity of the brackets made. The work plane 12 can comprise or be formed by a metal sheet or plate. It is clear that the sizes and conformation of the work plane 12 are coherent with the maximum length of the bars 100 to be worked.

[0030] A supply device 13 configured to supply at least one bar 100 along an axis of feed X is disposed upstream, or in correspondence with one end, of the work plane 12. The supply device 13 can be part of the machine 10 or it can be functionally part of another work machine disposed upstream of the machine 10. In a manner known per se, the bars 100 can be made available to the supply device 13 in the form of pre-cut segments, or wound continuously on a coil and cut to the desired length. The machine 10 comprises, at the upper part of, and facing, the work plane 12, a movement assembly 14 configured to move the bar 100 along the axis of feed X during the bending and / or curving operations. The bar 100 is preferably moved resting or slightly raised, for example by a few centimeters, with respect to the work plane 12. The movement assembly 14 comprises a guide 15 that extends parallel to the axis of feed X and the work plane 12, and a gripper device 16 associated sliding with the guide 15.

[0031] The gripper device 16 has the primary function of gripping and holding the bar 100 with its elements for gripping and dragging the bar 100, for the execution of the bending and / or curving work.

[0032] The gripper device 16 can be provided with cutting elements to perform the head and / or tail cut of the bar 100, for example before the start of the work or at its end. In this case, the gripper device 16 also has a cutting function.

[0033] Between the guide 15 and the gripper device 16 there can be interposed optional positioning members capable of varying the distance of the gripper device 16 from the work plane 12 or from the guide 15, for example as a function of the sizes of the bar 100 to be moved or the specific work step thereof. The positioning members can act along a positioning axis orthogonal to the axis of feed X and to the work plane 12. The positioning members can, for example, comprise an extensible arm associated sliding with the guide 15, and at the end of which the gripper device 16 is connected.

[0034] The work plane 12 comprises a bending zone where the bending of the bar 100 is effectively performed, by means of a bending assembly 19 that is part of the machine 10.

[0035] The bending assembly 19 comprises a slide 20 and at least two distinct bending units 21, 22 mounted on the slide 20, wherein each bending unit 21, 22 is suitable to perform a bend with a different bending radius Rl, R2. By bending, here and hereafter in the description we mean that the bar 100 is subjected to a localized deformation only in the zone where the bending unit 21, 22 chosen for the work, for example, in fig. 1 and 2, the first bending unit 21, acts.

[0036] The slide 20 can essentially consist of a metal sheet or plate coplanar to the work plane 12, inserted in an aperture 23 created therein. Each bending unit 21, 22 can be able to be selectively moved retracted with respect to the plane of the slide 20, and therefore with respect to the work plane 12.

[0037] Each bending unit 21, 22 comprises, in a known manner, its own contrast element 21a, 22a having an essentially cylindrical shape with a bending radius Rl, R2, and a bending element 21b, 22b selectively rotatable around the corresponding contrast element 21a, 22a in order to bend the bar 100 around the latter.

[0038] Two distinct contrast elements 21a, 22a advantageously have different bending radii Rl, R2. The slide 20 is able to be positioned in a direction of alignment Y that is transverse, in this specific case orthogonal, to the axis of feed X. The movement of the slide 20 is functional to align one or the other of the bending units 21, 22 with the axis of feed X, in such a way as to create a bend on the bar 100 with the desired bending radius Rl, R2. The alignment of a bending unit 21, 22 assumes that the external surface of the contrast element 21a, 22b is positioned essentially tangent to the axis of feed X.

[0039] The machine 10 can comprise, immediately upstream and / or downstream of the bending zone, that is, of the bending assembly 19, and aligned with the axis of feed X, two distinct holding devices 17, 18 associated with the work plane 12 and configured to temporarily hold the bar 100, for example during the execution of the bends to prevent unwanted curving in portions of the bar 100 that have to remain linear. The holding devices can also, or only, have a function of guiding the bars 100 being worked. The holding devices 17, 18 are advantageously disposed in a fixed position with respect to the work plane 12. The holding devices 17, 18 can be, for example, grippers, vices or similar devices.

[0040] The holding devices 17, 18 can be, in a known manner, able to be moved retracted with respect to the work plane 12. The holding function of the holding devices 17, 18 can be coordinated with that of the gripper device 16 which, once it has taken the bar to the bending position, can deliver it to the holding devices 17, 18 which clamp it during the execution of the bends. The gripper device 16 can then move backward, advance, or remain in position, in order to grip the bar 100 in a point that is functional for the movement for the following work.

[0041] The work plane 12 also comprises a curving zone disposed downstream of the bending zone where the curving of the bar 100 is effectively performed, by means of a curving assembly 24 that is part of the machine 10.

[0042] By curving, here and hereafter in the description we mean that the bar 100 is subjected to a continuous deformation for an extended longitudinal portion of the length of the bar 100, or for its entire length. In the field of mechanical working of bars 100, curving work is also known as calendering.

[0043] The curving assembly 24 is disposed aligned with the axis of feed X in a fixed position with respect to the work plane 12.

[0044] The curving assembly 24 comprises a single curving unit 25 provided with two contrast rollers 26 located in opposing position to each other with respect to the axis of feed X, and two distinct curving rollers 28, both able to be positioned with respect to the contrast rollers 26 in order to exert a desired deformation / curvature on the bar 100.

[0045] The curving rollers 28 are disposed side by side, on both sides, to the same contrast roller 26 and, by means of positioning means, can be moved close to or away from the axis of feed X in order to exert a desired deformation / curvature on the bar 100.

[0046] The curving assembly 24 can be selectively able to be moved retracted with respect to the work plane 12. This allows for rapid evacuation of the bar when the curving operations have finished.

[0047] At least one contrast roller 26 is provided with its own positioning means configured to allow a selective movement approaching / away from the other contrast roller 26, in order to adjust the passage gap between them in relation to the thickness of the bar 100.

[0048] The gripper device 16 is functionally coordinated with the bending assembly 19 and the curving assembly 24 in order to determine the desired advance of the bar 100 while one of the bending 21, 22 or curving 25 units works the bar 100.

[0049] Although not shown, the machine 10 can be associated with a programmable control, management, and command unit configured to control, manage, and command the movement assembly 15, the bending assembly 19 and the curving assembly 26 in a coordinated manner.

[0050] The operation of the machine 10 described heretofore, which corresponds to the method according to the present invention, is now described by illustrating an operating sequence for working a bar 100, figs. 1-7.

[0051] In a first operating step, the bar 100, previously supplied by the supply device 13, is picked up by the gripper device 16 and made to advance toward the bending assembly 19, fig. 1.

[0052] In a second operating step, the bending assembly 19 is positioned in such a way that the first bending unit 21 is in operating position, that is, with the external surface of the contrast element 21a essentially tangent to the axis of feed X, and when a segment of the bar 100 of a suitable length goes past the contrast element 21a, the bending element 21b is activated, rotating around the contrast element 21a determining, in this case, a counterclockwise bend with a first bending radius Rl, fig. 2. The second operating step is followed by a third operating step, in which the bar 100 is made to advance further and the bending assembly 19 is positioned in such a way that the second bending unit 22 is in operating position, that is, with the external surface of the contrast element 22a essentially tangent to the axis of feed X. When a segment of the bar 100 of a suitable length goes past the contrast element 22a, the bending element 22b is activated, rotating around the contrast element 22a determining, in this case, a clockwise bend with a second bending radius R2 different from the first bending radius Rl, fig. 3.

[0053] The third operating step can be followed by additional similar steps, in which other bends are carried out on the bar. In this case, a fourth advance step follows, in which the bar 100 is made to advance until it reaches the position of the curving assembly 24, which may initially be below the work plane 12, fig. 4.

[0054] In a fifth operating step, the curving assembly 24 is lifted, the contrast rollers 26 close against the bar 100 and one or both of the curving rollers 28, depending on the curvature to be performed, are brought closer to the axis of feed X to cause a certain pressure / force on the bar 100, while the latter is made to advance by the gripper device 16, fig. 5.

[0055] In a sixth operating step, the curving on the bar 100 is finished and the gripper device 16 is located in the immediate vicinity of the curving assembly 24, fig. 6. In a seventh operating step, the curving assembly 24 is brought into a retracted position with respect to the work plane 12 and the gripper device 16 can release the bar 100, which is now a finished product or piece, fig. 7. Before releasing the finished product, the gripper device 16 can cut a terminal portion thereof, which is evacuated as scrap. It is clear that modifications and / or additions of parts may be made to the machine 10 for working bars and to the corresponding method as described heretofore, without thereby departing from the field and scope of the present invention, as defined by the claims. It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of a machine for working bars and corresponding method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

[0056] In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.

Claims

CLAIMS1. Machine (10) for working bars comprising a fixed work plane (12) with which there are associated, in sequence along an axis of feed (X), a bending assembly (19) provided with at least two distinct bending units (21, 22) and a single curving unit (25), characterized in that said machine (10) comprises a gripper device (16) configured to move at least one bar (100) along said axis of feed (X) in a manner that is operationally coordinated with the operation of said bending units (21, 22) and / or of said curving unit (25).

2. Machine (10) as in claim 1, characterized in that said bending assembly (19) comprises a slide (20) on which said at least two distinct bending units (21 , 22) are mounted, wherein said slide (20) is able to be positioned in a direction of alignment (Y) that is transverse to said axis of feed (X).

3. Machine (10) as in any claim hereinbefore, characterized in that each of said bending units (21, 22) comprises its own contrast element (21a, 22a) with a different bending radius (Rl, R2) and a bending element (21b, 22b) selectively rotatable around said corresponding contrast element (21a, 22a) to bend said bar (100) around the latter.

4. Machine (10) as in any claim hereinbefore, characterized in that said single curving unit (25) comprises two contrast rollers (26) located in opposing positions to each other with respect to said axis of feed (X), and two distinct curving rollers (28), both able to be positioned with respect to said contrast rollers (26) in order to exert a desired deformation / curvature on said bar (100).

5. Machine (10) as in any claim hereinbefore, characterized in that said gripper device (16) is provided with gripping elements to hold said bar (100) and optional cutting elements to perform the head and / or tail cut of said bar (100).

6. Machine (10) as in any claim hereinbefore, characterized in that it comprises two distinct holding devices (17, 18) associated with said work plane (12) respectively upstream and downstream of said bending assembly (19).

7. Machine (10) as in claim 6, characterized in that each of said bending units (21, 22), said curving unit (25) and said holding devices (17, 18) are able to be moved retracted with respect to said work plane (12).

8. Machine (10) as in claim 6, characterized in that said gripper device (16) is part of a movement assembly (14) also comprising a guide (15) which extendsparallel to said axis of feed (X) and to the work plane (12), and with which said gripper device (16) is associated sliding.

9. Method for working bars comprising: a first advance step, in which at least one bar (100) is held by a gripper device (16) which makes it advance along an axis of feed (X) toward a bending assembly (19) provided with at least two distinct bending units (21, 22), one or more bending steps, in which one of said bending units (21, 22) is positioned aligned with said axis of feed (X) so as to perform a bend on said bar (100), a second advance step, in which by means of said gripper device (16) said bar (100) is made to advance toward a single curving unit (25), a curving step, in which by means of said gripper device (16) the bar (100) is made to advance in a controlled manner through said curving unit (25) and subsequently unloaded, wherein during said one or more bending steps and said curving step said gripper device (16) moves said at least one bar (100) in a manner that is operationally coordinated with the operation of said bending units (21 , 22) and / or of said curving unit (25).

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