Patent Document

BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention concerns a machine to bend tubular products, for example metal tubes to make fluid dynamic tubes, pipes, plants or other. In particular, the machine according to the present invention allows to bend such tubular products in an automated way and feed them substantially continuously onto a bend core. 
         [0003]    The present invention also concerns the bending method for the tubular elements. 
         [0004]    Here and in the following description and claims, by the term continuous feed we mean a feed of the tubular product starting from a product in a roll or in a bar, but which in any case has a starting length higher in multiples than the length of the segment which is the finished product. 
         [0005]    2. Description of Related Art 
         [0006]    Machines are known for the automatic or substantially automated bending of tubular elements, which allow to make parts of pipes, plants, tubing, fluidic connections or other, according to different design bends. 
         [0007]    The known bending machines for this type of product can be distinguished into substantially two groups, that is, bending machines with a core and bending machines without a core. 
         [0008]    In particular, in bending machines with a core the tubular elements are pre-cut to size into segments and then loaded onto the machine to feed them onto the core. 
         [0009]    This type of known machine, although it guarantees a high bending quality of large-size tubular elements with limited radiuses for each bending operation, needs different auxiliary equipment both for the preliminary cutting into segments and also for loading the segments onto the core, prior to the bending steps. 
         [0010]    This causes an increase in the costs of managing the machine and an increased operating complexity and automation. 
         [0011]    Moreover, very often, this type of known machine has a mainly manual use, with consequent operating delays, the need for specialized personnel and an increase in production costs. 
         [0012]    Moreover, known bending machines with a core, due to their conformation and operating conception, carry out a tail bending, that is, starting from the opposite end of the tube with respect to the end that is fed. 
         [0013]    Tail bending, for many products, needs to provide that the length of the segment is suitably longer than the length of the actual development of the tubular element once it is bent, since it is necessary that the segment is still gripped by the part not bent during the execution of the last bend. 
         [0014]    Some types of known bending machines are also characterized by the formation of high quantities of waste caused by short rectilinear sections of the end of the bent tubes. 
         [0015]    The formation of waste has two main reasons. On the one hand, the traditional machines with core, because of their operating conception, need the tube to be supported at one end, so that the section of tube which acts as a support causes waste to be eliminated at the end. On the other hand, waste is caused because, starting from the segment in the bending step, the external material stretches and creates a deforming effect on the end of the cut tube, which obliges one section to be eliminated. 
         [0016]    Coreless bending machines, on the contrary, are applied in particular for bending tubular elements of reduced diameter with high radiuses, and fed from a roll. 
         [0017]    These known machines, which provide a bending system with a matrix and clamp, and not a core, can entail, in the case where reduced radiuses of curvature are required, an ovalization of the usable section for the passage of the tubular element, and the fluidic characteristics of the tubular element itself may vary. 
         [0018]    In some conditions, a partial occlusion of the tubular element can occur at the bent point, with consequent lack of performance of the final product. 
       BRIEF SUMMARY OF THE INVENTION 
       [0019]    One purpose of the present invention is to produce a machine for bending tubular elements which allows an efficient bending both of tubular elements with an ample diameter with reduced radiuses of curvature, and tubular elements of a limited diameter with ample bending radiuses. 
         [0020]    A further purpose of the present invention is to make a machine for bending tubular elements which is simple and economic, which allows great operating automation, which uses a bend core and can be fed substantially continuously. 
         [0021]    Another purpose of the present invention is to perfect a method for bending tubular elements which overcomes the shortcomings of the state of the art. 
         [0022]    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. 
         [0023]    The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea. 
         [0024]    In accordance with the above purposes, a machine for bending tubular elements according to the present invention comprises bending means provided with at least a bending arm able to act on an external surface of the tubular element in order to make a bend, and with a bend core able to be disposed inside the tubular element to contrast from the inside the action of the bending arm, and to conform, in a desired way, the bend of the tubular element. 
         [0025]    The machine according to the present invention also comprises movement means able to move the tubular element in a linear manner, both in the first feed step toward the bending means and also during the bending steps. 
         [0026]    According to a characteristic feature of the present invention, the bending machine also comprises holding means selectively connected to the bend core in order to keep the latter in a condition of substantial suspension inside the tubular element. 
         [0027]    The condition of suspension defined by the holding means is such that the movement means feed the tubular element toward the bending means in a direction and sense concordant with a work direction of the bending means on the tubular element. 
         [0028]    In this way, the tubular element is worked head-wise, that is, starting from the same end as that with which the tubular element is fed. 
         [0029]    This work condition allows to feed the tubular element substantially continually, exploiting the advantages of automation of known coreless machines. Unlike these known machines, the machine according to the present invention, also exploits the advantageous characteristics of using the core to carry out the bending. 
         [0030]    In this way, it is possible to provide a machine for bending tubular elements which is substantially automated, or can be automated, more or less completely, which allows to bend with both large and reduced radiuses, substantially of the whole dimensional range of tubular elements. 
         [0031]    With the present invention there is a reduction in operating and management costs of the machine, optimizing the yield. 
         [0032]    According to a variant, the holding means are of the magnetic type, that is, they provide at least a magnetic element disposed on the perimeter around the zone where the tubular element is disposed in the operating condition. By magnetic element, here and in the following description and claims, we mean any element suitable to exert a magnetic force of attraction on an element, which is also magnetic, magnetized or has magnetic means (in this case the bend core), therefore including permanent magnets, electromagnets, elements which can be magnetized and any other element suitable for the purpose. 
         [0033]    The at least one magnetic element, or the plurality of magnetic elements, is/are disposed around the tubular element in order to generate a magnetic field which keeps the core in a condition of suspension inside the tubular element. 
         [0034]    The position of the magnetic element or elements is lateral, that is, not interfering with the axis of feed of the tubular element, and this determines a considerable operating advantage, promoting the automation of the advance and feed movements of the tubular element toward the bending means. 
         [0035]    The bending core is disposed axially in correspondence to the central zone of magnetic balance, thus staying in a condition of substantial suspension inside the space defined by the magnetic elements. 
         [0036]    The tubular element is thus fed by the movement means in the direction of feed, inserting itself into the interspace defined between the magnetic elements and the bend core, without any interference by any possible supports of the bend core or the tubular element itself. In this disposition, the tubular element is further fed by the movement means in the same direction and the same sense, in a manner coordinated with the drive of the bending means in order to carry out the bends required. 
         [0037]    In this solution, it is obvious that no working waste at all is produced, in that once a first portion of tubular element has been bent according to the desired pattern, the tubular element can be cut exactly to size, separating only the bent portion. In this condition, the tail end of the remaining tubular element coincides with the leading end of the new portion to be bent, and so on. 
         [0038]    According to a variant, the magnetic elements can be conformed so as to command an axial recovery movement of the core after the bending steps. 
         [0039]    According to another variant, the holding means comprise a first gripping member disposed in cooperation with a first end, or tail end, of the bend core, and able to maintain the bend core in the suspended condition during the feed steps of the tubular element in the direction of feed. 
         [0040]    In this variant solution, the holding means also comprise a second gripping member disposed in cooperation with a second end, or tail end, of the bend core, and able to maintain the bend core in the suspended condition during the bending steps of the tubular element. 
         [0041]    In this solution too, as in the previous one, the holding means are disposed and act laterally with respect to the position of the tubular element, so that there is no interference by the holding means with respect to the axis of feed of the tubular element. 
         [0042]    In this variant solution, the tubular element is initially fed head-wise by the movement means. Then the tubular element is cut or sheared in order to define a segment of desired length. 
         [0043]    Subsequently the segment is fed along the direction of feed so as to free the tail end of the bend core. 
         [0044]    In this condition the second gripping member is activated and the first gripping member is de-activated, so that the movement means can feed the segment in the same direction and sense in order to bring it into cooperation with the bending means and carry out the bends required. 
         [0045]    The suspended condition of the bend core is guaranteed at the rear by the second gripping member. 
         [0046]    With this variant, the bending occurs only on a segment coinciding with the dimension of the development of the portion to be bent, so as to facilitate the operations to move the segment, and to further improve the quality results of the bend carried out. 
         [0047]    According to a further variant, the holding means comprise a support member, for example made of flexible material, articulated meshes or other, which support and feed the core inside a tubular bar, from which a plurality of bent portions are made. 
         [0048]    In this variant solution, the core is moved by the movement means, axially to the tubular bar by a tail end of the latter, until the leading end is reached, and then positioned in cooperation with the bending arm of the bending means. 
         [0049]    The movement of the tubular bar to bend its portions is, however, carried out head-wise. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0050]    These and other characteristics of the present invention will become apparent from the following description of some preferential forms of embodiment, given as a non-restrictive example with reference to the attached drawings wherein: 
           [0051]      FIG. 1  is a schematized view, lateral and partially sectioned, of a first form of embodiment of a machine for bending tubular elements according to the present invention, in a first operating step; 
           [0052]      FIG. 2  is a schematized view, lateral and partially sectioned, of the bending machine in  FIG. 1 , in a second operating step; 
           [0053]      FIG. 3  is a schematized view, lateral and partially sectioned, of the bending machine in  FIG. 1 , in a third operating step; 
           [0054]      FIG. 4  is a schematized view, lateral and partially sectioned, of a second form of embodiment of a machine for bending tubular elements according to the present invention, in a first operating step; 
           [0055]      FIG. 5  is a schematized view, lateral and partially sectioned, of the bending machine in  FIG. 4 , in a second operating step; 
           [0056]      FIG. 6  is a schematized view, lateral and partially sectioned, of the bending machine in  FIG. 4 , in a third operating step; 
           [0057]      FIG. 7  is a schematized view, lateral and partially sectioned, of a third form of embodiment of a machine for bending tubular elements according to the present invention, in a first operating step; 
           [0058]      FIG. 8  is a schematized view, lateral and partially sectioned, of the bending machine in  FIG. 7 , in a second operating step; 
           [0059]      FIG. 9  is a schematized view, lateral and partially sectioned, of the bending machine in  FIG. 7 , in a third operating step. 
       
    
    
       [0060]    In order to facilitate comprehension, the same reference numbers have been used, where possible, to identify common elements in the drawings that are substantially identical. It is understood that elements and characteristics of one form of embodiment can conveniently be incorporated into other forms of embodiment without further clarifications. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0061]    With reference to  FIGS. 1 ,  2  and  3 , a first form of embodiment of a machine  10  used for the bending of tubular elements, or tubes  11  is shown. 
         [0062]    Both for this form of embodiment described and for the forms of embodiment described hereafter, the relative representations are deliberately schematic, in order to better understand the characteristics of the machine according to the present invention. 
         [0063]    Operating details such as, for example, the diameters of the tubes, the radiuses of curvature achieved, the sizes of the core and others, have been deliberately chosen randomly so as not to constrain the individual forms of embodiment to specific operating solutions, also considering the fact that one of the main advantages of the present invention is the excellent operating applicability of the bending machine substantially for any type of tube with any radius of curvature. 
         [0064]    In this case, the machine  10  comprises a bending member  12  and a movement member  13 , in this case represented by an unwinding reel  23 . The movement of the tube  11 , in a manner known in the state of the art, is achieved by means of a motorized roller-way or with other systems of an alternative type, such as a gripper, or similar means, not shown here in detail, which carry out both the first feed of the tubes  11  toward the bending member  12  and the advance of the tubes  11  during the work steps. 
         [0065]    In the following description, the reference numbers  13 ,  113 ,  213  are used to indicate in general the member which moves the tube  11  linearly in the direction of feed which, being known, is not shown in detail in the drawings. 
         [0066]    The machine  10  according to the present invention also comprises a holding member  15 , the function of which will be described in detail hereafter. 
         [0067]    The bending member  12  comprises a bend core  16  and a bending arm  17 , which is mobile with respect to the bend core  16  in order to bend the tubes  11  fed. 
         [0068]    In particular the bend core  16  is disposed inside the tubes  11  so as to function as contrast, inside the tube  11 , to the bending action exerted externally by the bending arm  17 . 
         [0069]    The bend core  16  comprises, in its turn, a polarized support bar  19 , a contrasting ogive  20  and, in the case shown in the drawings, at least a bend-follower element  21  disposed articulated at the head of the contrasting ogive  20 . 
         [0070]    There may be only one bend-follower element  21 , as in the drawings, or of the multiple type, or it may not be there at all, if the type of bending and/or machine does not require it. 
         [0071]    The bending arm  17  is of the substantially known type and is only shown schematized in the drawings. The bending arm  17  acts externally to the tube  11  to be bent in order to confer on the latter, in coordination with the advance imparted by the movement member  13 , the bending radius envisaged. The bending aim  17  can be selectively positioned on different planes transverse to the direction F, in order to bend the tubes  11  on different planes. 
         [0072]    The machine  10  also comprises a cutting tool  22 , for example a milling cutter or other, in this case, disposed downstream of the holding member  15  and upstream of the bending member  12 , which allows to cut to size one segment of tube  11 , at the end of the bending steps. 
         [0073]    Within the framework of the present invention, here and in the variant solutions shown hereafter, it is understood that the cutting tool  22  could also be disposed downstream of the bending member  12 , or there could be one or more cutting members  22  upstream and one or more cutting tools downstream of the bending member  12 . 
         [0074]    The tube  11  is fed in the same direction of feed “F”, and in the same sense, both in the feed step of the tube  11  to the bending member  12 , and also during the bending steps. The direction and sense of feed define a head-wise feed and a head-wise working of the tube  11 . 
         [0075]    The holding member  15  comprises at least a magnetic element  25 ; by this term we mean permanent magnets, electro-magnets or other similar or comparable element. The magnetic element or elements  25  are disposed annularly around a zone in which the tube  11  is fed, in proximity to the bending member  12 , defining an interspace between it and the bend core  16  in which the tube  11  can be inserted. 
         [0076]    The permanent magnets  25  thus disposed define, with their magnetic fields, a median zone, axial to the direction of feed “F”, of magnetic balance. The bend core  16  is disposed with its support bar  19  in this median zone of magnetic balance. The support bar  19 , being polarized, remains substantially suspended in correspondence to this zone, also absorbing, among other things, the axial forces which they generate during bending. 
         [0077]    Therefore, the whole bend core  16  is maintained suspended by the action of the magnetic fields generated by the permanent magnet or magnets  25 , so as to allow the feed in the direction “F” required, without risk of interference with possible structures for the support of the bend core  16  in its operating position. 
         [0078]    As shown in sequence in  FIGS. 1 ,  2  and  3 , in this form of embodiment of the machine  10 , the tube  11  is fed from a roll by the action of the unwinding reel  23  in the direction of feed “F”, and directed head-wise toward the bending member  12 . 
         [0079]    Before reaching the bending arm  17 , the leading end of the tube  11  is made to pass inside the holding member in the interspace defined between the permanent magnet or magnets  25  and the bend core  16 , so that the latter is disposed in suspension inside the tube  11 . 
         [0080]    In the form of embodiment shown in  FIGS. 4 ,  5  and  6 , a second form of embodiment of the machine  110  according to the present invention is shown schematically. 
         [0081]    In this case the machine  110  comprises a bending member  12 , a movement member  113 , and a holding member  115 , the latter two being of a different conformation than has so far been described. 
         [0082]    The bending member  12  is the same as that described for the solution in  FIGS. 1 ,  2  and  3 , and comprises the bend core  16  and the bending arm  17 , for bending the tubes  11  fed. 
         [0083]    The movement member  113 , in this case, comprises a motorized unwinding reel  23  able to unwind from a roll the tube  11  to be bent, and a movement pincers  123  disposed downstream of the unwinding reel  23  and upstream of the bending member  12 , with respect to the direction of feed “F”. 
         [0084]    In this case too there can be other feed members present, but not shown here, such as a roller-way, etc. 
         [0085]    In this variant solution too, the tube  11  is fed head-wise in the same direction of feed “F”, and in the same sense, both by means of the unwinding reel  23  and also by means of the movement pincers  123 . 
         [0086]    The holding member  115  comprises a first gripping pincers  26  and a second gripping pincers  27  disposed in cooperation with the bend core  16 , in order to keep it in a suspended condition, acting on one side of the tube  11 . 
         [0087]    In particular the first gripping pincers  26  is suitable to cooperate with a tail end of the support bar  19  of the bend core  16 ; while the second gripping pincers  27  is suitable to cooperate with the contrasting ogive  20  of the bend core  16 . The operating sequence of the two gripping pincers  26  and  27  will be described in detail hereafter. 
         [0088]    The machine  110  in this case also comprises a cutting tool  122 , for example a milling cutter or other, in this case disposed upstream of the first gripping pincers  26 , and able to cut to size a segment of tube  11  before bending. 
         [0089]    As shown in sequence in  FIGS. 4 ,  5  and  6 , in this form of embodiment of the machine  110 , the tube  11  is initially unwound from a roll by the action of the unwinding reel  23 , and moved in the direction of feed “F” by the feed member  113 , and directed head-wise toward the bending member  12 . 
         [0090]    During the feed of the tube  11 , the bend core  16  is kept in a suspended condition by the action of the second gripping pincers  27 . 
         [0091]    Before reaching the second gripping pincers with the leading end of the tube  11 , the unwinding reel  23  stops the feed of the tube  11  and the cutting tool  122  cuts to size the segment of tube  11  to be bent. Before the definitive cut of the segment of tube  11 , the segment is associated to the movement pincers  123 . In a variant of this solution two cutting units can be provided, in which a first cuts one segment made from multiples of the product, and a second is positioned after the bending member  12  and cuts to size the bent tube. 
         [0092]    Once the cutting to size has been carried out, the unwinding reel  23  partly recovers the tube  11 , separating from the cut segment, and freeing a back section of the support bar  19  of the bend core  16 . 
         [0093]    In this condition, the first gripping pincers  26  is brought into cooperation with this back section of the support bar  19 , and subsequently the second gripping pincers  27  is discharged, releasing the contrasting ogive  20 . 
         [0094]    At this point the movement pincers  123  feed the segment head-wise in the direction F in the same sense of feed executed with the unwinding reel  23 , so as to bring it into cooperation with the bending member  12  and perform the required bends. 
         [0095]    In the form of embodiment shown in  FIGS. 7 ,  8  and  9 , the bending machine according to the present invention is shown in its entirety with the reference number  210 . 
         [0096]    In this case the machine  210  comprises a bending member  12 , a movement member  213 , and a holding member  215 , the latter two having a conformation different from both the solutions so far described. 
         [0097]    The bending member  12  is the same as that described for the previous solutions and comprises the bend core  16  and the bending arm  17 . 
         [0098]    In this case the tube, rather than being fed from a roll, is fed in bars  211  of a length substantially multiple to the length of the individual segments to be bent. 
         [0099]    In this case, the movement member  213  comprises movement pincers  223  disposed in cooperation with a back end of the bar  211 , in order to determine a movement thereof toward the bending member  12  in the direction of feed F. 
         [0100]    The holding member  215  comprises a support bar  219  directly connected to the back part of the contrasting ogive  20  of the bend core  16 . 
         [0101]    The support bar  219  is made of flexible material, with articulated meshes or other, so as to be able to feed the contrasting ogive  20  from the back surface of the tubular bar  211 , with a curvilinear path, and in any case guarantee sufficient rigidity in the operating position of the contrasting ogive  20 . 
         [0102]    The machine  210  in this case also comprises a cutting tool  222 , for example a milling cutter or other, in this case disposed upstream of the bending arm  17 , and able to cut to size a segment of tube  11  after bending. 
         [0103]    As shown in sequence in  FIGS. 7 ,  8  and  9 , in this form of embodiment of the machine  210 , the tubular bar  211  is initially fed from a store and disposed in the direction of feed F. From here the movement pincers  223  feed the bar  211  head-wise toward the bending member  12 . 
         [0104]    Once the bar  211  is disposed in cooperation with the bending member  12 , the bend core  16  is inserted axially to the bar  211  from a back end of the latter, until it reaches the position of cooperation, inside the bar  211 , with the bending arm  17 . 
         [0105]    The bar  211  is then progressively fed by the movement pincers  233  to carry out the desired bends. 
         [0106]    At the end of bending, the cutting tool  222  cuts the segment to size, in order to resume the bending cycle of a new section of the bar  211 , always fed head-wise. 
         [0107]    It is clear that modifications and/or additions of parts or steps may be made to the machine  10  and the cutting method as described heretofore, without departing from the field and scope of the present invention. 
         [0108]    For example, it comes within the scope of the present invention to provide that cutting tools  22 ,  122 ,  222  are disposed downstream of the bending member  12 , or in another position with respect to the bending member  12 , depending on the different operating conditions. 
         [0109]    According to another variant, the support bar  19  is polarized by means of a magnetic core, or an electric current or other known polarization system, able to generate a magnetic field contrasting the action of the field generated by the permanent magnets  25 , or by the electro-magnets. 
         [0110]    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 shall certainly be able to achieve many other equivalent forms of machine for bending tubular products and relative cutting method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

Technology Category: b