Abstract:
The invention relates to a machine for bending a profile in two bending directions, that comprises a bending tool including at least two clamping forms ( 19 ) centered on the profile bending axis and having the shape of disks having planar junction surfaces ( 19   a ) extending in planes perpendicular to said bending axis, in which are formed two rectilinear grooves ( 20   b,    21   b ) and a peripheral rebate ( 22   b ) extending between said grooves and profiled as a continuation thereof, the grooves and the rebate being adapted so that, in the joined position of the junction surfaces ( 19   a ) of two clamping foams, the joined grooves define two clamping ducts of a profile and the joined rebates define a profile-winding bearing surface extending between said clamping ducts.

Description:
FIELD OF THE INVENTION 
     The invention concerns a machine for bending a profile in two bending directions and is also directed to a bending tool for such a bending machine. 
     DESCRIPTION OF RELATED ART 
     At present standard bending machines comprise means for holding profiles and moving them along a longitudinal axis (x) and a bending head rotatable about a bending axis (z), said bending head including as standard a bending roller and a clamping jaw having bearing surfaces between which a profile to be bent passes, is clamped and then bent:
         the bending roller axis coinciding with the bending axis (z), and   the clamping jaw being mobile in translation relative to the bending roller along an axis perpendicular to the bending axis (z) between a position joined with said bending roller for clamping and bending a profile to be bent and a position spaced from said bending roller for introducing a profile to be bent between the latter and said clamping jaw.       

     Such machines have a kinematic combining relative movement of the bending roller and the clamping jaw along an axis perpendicular to the bending axis (z) and simultaneous rotation of the bending roller and the clamping jaw about the bending axis (z) in the position in which they are joined. 
     One particular advantage of such a kinematic is to enable the design of machines for bending profiles in two bending directions and many bending machines of this type exist at present. 
     On the other hand, this kinematic leads to the production of relatively complex bending heads that furthermore have a relatively large overall size. 
     Moreover, an additional disadvantage of such bending machines is that the bending angle is limited to 180°, or less than 180° if the end of the bent length carries an item such as a nut to enable disengagement of the profile after bending. 
     One solution to alleviating these drawbacks has been to design bending machines such as are described in particular in the patent applications FR2117745, EP1561522 and EP0737526 having a totally different kinematic and the bending head of which comprises:
         at least two clamping forms whose axis is the bending axis (z), taking the form of discs having plane junction faces extending in planes perpendicular to said bending axis, in which are formed a rectilinear groove with a longitudinal axis perpendicular to the bending radius, having an end face for introduction of a profile (P), and a peripheral rebate profiled in continuity with the introduction face of said groove, said groove and said rebate being such that, in the joined position of the junction faces of two clamping forms, two joined grooves delimit a duct for bending a profile (P) having an end face for introducing said profile, and the joined rebates define, in continuity with said introduction face, a bending bearing surface for said profile,   means for relative movement in translation of the clamping forms along the bending axis (z), adapted to move them between a spaced-apart position for introducing and removing a profile (P) and a joined position for bending said profile, and   rotation drive means adapted to drive simultaneous rotation of the clamping forms in their joined position.       

     Such bending machines therefore have a kinematic combining relative movement of the clamping forms along the bending axis (z) and simultaneous rotation of the bending forms about that bending axis (z) in the position in which they are joined. 
     According to this principle, the bending head thus includes clamping forms whose axis is the bending axis (z) that are adapted to move along that axis and to turn about it. 
     This design significantly reduces the overall size of the bending heads and simplifies the design of said bending heads because of a kinematic having a single reference axis, namely the bending axis (z). 
     Moreover, in the spaced-apart position of the clamping forms, the latter totally free the plane in which the profile is situated, with the result that removing it does not give rise to any problem even if the bending angle is greater than 180°. 
     On the other hand, the major drawback of such bending machines is that they enable bending in only one bending direction. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention aims to alleviate this drawback and has for its main object the provision of a bending machine of the type described above, i.e. the kinematic of which has only one reference axis, adapted to bend a profile in two bending directions. 
     Another object of the invention is to provide a machine for bending a profile in two bending directions enabling bending angles greater than 180° to be produced. To this end, the invention is aimed at a bending machine having a bending head as described in the above preamble, characterised in that:
         the clamping forms include in each of their junction faces a rectilinear second groove following with the rectilinear first groove a pair of grooves delimiting in the joined position of the junction faces of the two clamping forms two clamping ducts between the introduction faces of which extends the bending bearing surface for the profiles (P) formed by the two peripheral rebates joined, the arrangement of said grooves and rebates being such that the bending bearing surface for the profiles delimits between the introduction faces of the two clamping ducts a circular arc at least equal to 270° adapted to enable the bending of a length of profile (P):
           either in a first bending direction using one of the two pairs of grooves, by rotation of the clamping forms in a first rotation direction,   or in a second bending direction using the other pair of grooves, by rotation of the clamping forms in a rotation direction that is the opposite of the first rotation direction,   
           means for relative movement of the means for holding the profile (P) and the bending head are adapted to place the axis of one or the other pair of grooves on the longitudinal axis (x).       

     Thus the invention consists in providing two grooves in the junction face of each clamping form, each for bending profiles in one bending direction, and a rebate, arranged so that the groove not being used for bending is “retracted” relative to the longitudinal bending axis. This solution therefore produces machines for bending in two bending directions including bending heads of identical overall size and design to those of present-day bending machines the kinematic of which has only one reference axis. 
     This design further enables bending angles greater than 180° to be produced, notably as a function of the required maximum value of that bending angle, the pair of grooves produced in the junction face of each clamping form is advantageously such that the rebate produced between the introduction faces of said grooves delimits a circular arc between 270° and 315° inclusive. 
     According to another advantageous embodiment of the invention aimed at a bending machine comprising two rules disposed on the upstream side of the clamping forms and adapted to enable the bending of a profile by each of the pairs of grooves, said rules are advantageously mounted on a single carriage associated with means for moving said carriage. 
     This arrangement of the rules on a single carriage constitutes a highly advantageous disposition significantly simplifying the bending machine. The movement of such rules requires only one guide and only one feed control system, instead of the two guides and two control systems required for present-day machines enabling bending in two directions. 
     According to another advantageous embodiment of the invention, the means for driving the clamping forms in rotation include an axial opening produced in each of said clamping forms and a rotary shaft adapted to extend in these openings, said openings and said rotary shaft having conjugate members for immobilizing them relative to each other in rotation. Moreover, in a first advantageous variant of the invention aimed at a bending machine comprising two clamping forms, one of said clamping forms, referred to as the fixed form, is fixed in translation along the bending axis (z) and the other bending form, referred to as the mobile form, is mounted on means for moving said mobile clamping form in translation along the bending axis (z). 
     On the subject of this first variant, the rotary shaft is furthermore advantageously carried by means for moving said rotary shaft in translation along the bending axis (z) adapted to enable it to be held engaged with the two clamping forms in each of the relative positions of said clamping forms and notably the joined and spaced apart extreme positions thereof. Moreover, in the spaced-apart position of the two clamping forms the means for moving the rotary shaft in translation along the bending axis (z) are advantageously adapted to enable the latter to be placed either in a position referred to as the deployed position in which said rotary shaft is engaged with the clamping forms or in a position called the retracted position in which said rotary shaft frees, between the two junction faces of said clamping forms, a space adapted to enable the passage of the profile in order to change the bending direction. 
     This disposition significantly simplifies the kinematic of movement of the profiles on changes of bending direction, because this requires only one movement along an axis orthogonal to the longitudinal axis (x). 
     According to a second advantageous variant of the invention aimed at a bending machine comprising three clamping forms, those three clamping forms advantageously consist in:
         a clamping form referred to as the intermediate clamping form having opposite upper and lower junction faces,   a clamping form referred to as the upper clamping form having a junction face adapted to cooperate with the upper junction face of the intermediate clamping form, and   a clamping form referred to as the lower clamping form having a junction face adapted to cooperate with the lower junction face of the intermediate clamping form,   the grooves and rebates produced in the upper clamping form and the upper junction face of the intermediate clamping form having dimensions different from those of the grooves and rebates produced in the lower clamping form and the lower junction face of the intermediate clamping form to enable the bending of profiles with different sections. Moreover, this bending machine then further comprises means for relative movement of the means for holding the profile and the bending head adapted to position said profile facing one or the other pair of clamping forms.       

     Furthermore, in this second variant:
         one of the upper and lower bending form is advantageously fixed in translation along the bending axis (z), and   the rotary shaft is advantageously constrained to move in translation with the other of the upper and lower clamping form and is adapted to bring the three clamping forms to their joined position against the action of spring means disposed between the respective junction faces of said clamping forms.       

     The invention is also directed to a tool for bending a profile about a bending axis (z), comprising at least two bending forms having junction faces in which are formed a rectilinear groove and a peripheral rebate profiled in continuity with said groove. According to the invention, the clamping forms of this tools include, formed in each of their junction faces, a rectilinear second groove foaming with the rectilinear first groove a pair of grooves delimiting in the joined position of the junction faces of the two clamping forms two clamping ducts between the introduction faces of which extends the bending bearing surface for the profiles (P) formed of the two peripheral rebates joined, the arrangement of said grooves and rebates being such that the winding bearing surface for the profiles delimits between the introduction faces of the two clamping ducts a circular arc at least equal to 270° adapted to allow the bending of a length of profile (P):
         either in a first bending direction using one of the two pairs of grooves, by rotation of the clamping forms in a first direction,   or in a second bending direction using the other pair of grooves, by rotation of the clamping forms in a rotation direction that is the opposite of the first rotation direction.       

     The invention further encompasses a tool as defined hereinabove having separately or in combination any of the advantageous features stated in the text and the claims of the present application. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features, aims and advantages of the invention will emerge from the following detailed description with reference to the appended drawings, which represent by way of non-limiting examples two preferred embodiments of the invention and a variant of the second embodiment. In these drawings: 
         FIG. 1  is a diagrammatic perspective view of a first embodiment of a bending machine of the invention including two clamping forms, 
         FIG. 2  is a partially cut away front view of the bending head of this first embodiment in the position with the two clamping forms joined, 
         FIGS. 3   a  and  3   b  are two partial and partially cut-away front views representing two distinct states of the bending head of this first embodiment in the spaced-apart position of the two clamping forms, 
         FIG. 4  is a perspective view of a clamping form of the invention, 
         FIG. 5  is a diagrammatic perspective view of a second embodiment of a bending machine of the invention including three bending forms, 
         FIG. 6  is a partially cut-away front view of the bending head of this second embodiment in the position with the three clamping forms joined, 
         FIG. 7  is a partial and partially cut-away front view representing the bending head of this second embodiment in the spaced-apart position of the three clamping forms, 
         FIG. 8  is a partially cut-away front view, showing in particular the partially cut-away clamping forms, of the bending head of a variant of this second embodiment in the position with the two clamping forms joined, and 
         FIGS. 9   a  to  9   d  are four diagrams representing two successive bending operations carried out using the first embodiment of the bending machine according to the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The bending machines of the invention represented by way of example in the figures are machines for bending in two bending directions a profile P carried by means of any type of means known in themselves, schematically represented at D, adapted to move said profile along a horizontal axis (x). 
     Note that, in order to simplify the detailed description given hereinafter, the bending machines are described in their usual position of use in which, in particular, the bending axis (z) is a vertical axis and the displacement axis (x) is a horizontal axis. Consequently, the terms vertical, horizontal, etc. relate to such a position. 
     The bending machine having two clamping forms represented in  FIG. 1  comprises, firstly, a frame  1  including a vertical front plate  2 . 
     This bending machine comprises a first carriage  3  adapted to slide horizontally along a horizontal axis Y relative to the frame  1  and including a vertical table  4  having horizontal slides such as  5  adapted to cooperate with horizontal rails such as  6  fainted on the front plate  2  of the frame  1 . 
     This first carriage  3  additionally includes an upper horizontal table  7  on which a second carriage  8  is mounted to slide in translation on said horizontal axis Y and which has a horizontal plate  9  on the underside of which are disposed horizontal rails such as  10  adapted to slide in slides such as  11  provided on said upper table  7  of the first carriage  3 . 
     The second carriage  8  also includes two parallel plates  12 ,  13  extending vertically on the horizontal plate  9  each having toward their upper end a slide  14  that extends horizontally along an axis X perpendicular to the axis Y and thus parallel to the axis (x) of movement of the profile P. 
     Each of these slides  14  is adapted to house a sliding rail  15  for supporting a guide rule  16 ,  17  of standard type, i.e. including a longitudinal bearing and guide groove for the profile to be bent. 
     The bending machine represented in  FIG. 1  further includes a bending tool disposed in front of the second carriage  8  and adapted to cooperate with one or the other of the guide rules  16 ,  17  in order to enable bending in two bending directions. 
     This tool consists of two clamping forms  18 ,  19  whose axis is a vertical bending axis (z) taking the form of discs having plane junction faces  18   a ,  19   a  extending in horizontal planes (X, Y) perpendicular to said bending axis and at the periphery of which are formed two rectilinear grooves with a longitudinal axis perpendicular to the bending radius, respectively grooves  20   a ,  21   a  for the upper clamping form  18  and grooves  20   b ,  21   b  for the lower clamping form  19 , between which extends a respective peripheral rebate  22   a ,  22   b.    
     These grooves  20   a ,  20   b ,  21   a ,  21   b  and rebates  22   a ,  22   b  are, firstly, such that in the position with the junction faces  18   a ,  19   a  of the two clamping forms  18 ,  19  joined two joined grooves  20   a - 20   b ,  21   a - 21   b  delimit a clamping duct for a profile P and the joined rebates  22   a - 22   b  define a bending bearing surface for said profile. 
     Moreover, the arrangement of said grooves and rebate, in association with one or the other rule  16 ,  17 , enables the bending of a length of profile P:
         either in a first bending direction using one of the two pairs of grooves  20   a - 20   b , by rotation of the clamping forms  18 ,  19  in a first rotation direction,   or in a second bending direction using the other pair of grooves  21   a - 21   b , by rotation of the clamping forms  18 ,  19  in a rotation direction that is the opposite of the first rotation direction.       

     In the example represented, and in order to fulfil the aforementioned functions, the faces F 20 , F 21  for introduction of the profiles P of the two grooves  20   a ,  21   a  or  20   b ,  21   b  formed on a clamping form  18  or  19  (i.e. the faces of these grooves with the rebate  22   a  or  22   b  between them), delimit between them an angle α equal to 270°, which can be increased up to 315°. 
     Each clamping form  18 ,  19  further includes an axial circular opening  23  in which splines  24  are formed. 
     These clamping forms  18 ,  19  are further adapted:
         to be moved relative to each other in translation along the bending axis (z) between a spaced-apart position of the junction faces  18   a ,  19   a  for introducing and removing a profile and a joined position for bending said profile, and   to be driven simultaneously in rotation in the position with the junction faces  18   a ,  19   a  joined.       

     To this end, and firstly, the lower clamping form  19  is fixed in terms of movement in translation along the bending axis (z) and rests on fixed horizontal friction ring  25 . 
     For its part, the upper clamping form  18  is mobile in terms of movement in translation along the bending axis (z) and to this end is mounted by means of a bearing  28  below the lower end of a vertically arranged rod  26   a  of an actuator  26  the body of which is fastened to a bridge  27  extending above the upper table  7  of the first carriage  3 , said actuator being adapted:
         in its deployed position, to exert a clamping force holding the junction faces  18   a ,  19   a  of the clamping forms  18 ,  19  joined, and   in its retracted position, to hold the two clamping forms  18 ,  19  in their spaced-apart position for introducing or removing a profile P or for changing the bending direction, as described hereinafter.       

     For their part, the means for driving the two clamping forms  18 ,  19  in rotation include a vertical shaft  29  that extends along the bending axis (z), is engaged in the openings  23  and has ribs  30  conjugate with the splines  24 , said shaft being driven in rotation by a gearmotor  31   a - 31   b  carried by the first carriage  3  between the upper table  7  and a horizontal lower table  32  of the latter carriage. 
     Moreover, the rotary shaft  29  is constrained to move in translation with the vertical rod  33   a  of an actuator  33  the body of which is disposed on the lower table  32  of the first carriage  3 , said actuator being adapted:
         in its deployed position, to hold the rotary shaft  29  engaged with the two clamping forms  18 ,  19  in each of the relative positions of said clamping forms, and notably its joined and spaced-apart extreme positions, represented in  FIGS. 2 and 3   a , and   in its retracted position, and in the spaced-apart position of the two clamping forms  18 ,  19 , to enable the rotary shaft  29  to be placed in a retracted position in which, as shown in  FIG. 3   b , said rotary shaft frees a space between the two junction faces  18   a ,  19   a  of said clamping forms adapted to allow the passage of the profile P for changing the bending direction.  FIG. 4  is a perspective view of the first embodiment.       

     According to this principle, the rotary shaft  29  has the function of indexing the relative position in rotation of the two clamping forms  18 ,  19 , at the same time as enabling, in the spaced-apart position of the clamping forms  18 ,  19 , movement of the first carriage  3  along the axis Y for changing the direction of bending the profile P. 
     The bending machine represented in  FIG. 5  has three clamping forms, adapted not only to enable bending of profiles in two bending directions but also to enable bending of two profiles P with different sections. 
     This bending machine comprises, firstly, a frame  41  including a vertical front plate  42 . This bending machine further comprises a first carriage able to slide vertically along a vertical axis Z relative to the frame  41  and consisting of a vertical table  43  having vertical rails such as  44  adapted to slide in vertical slides such as  45  on the front plate  42  of the frame  41 . 
     This bending machine also includes a generally stirrup-shaped second carriage  46  consisting of:
         a vertical table  47  able to slide horizontally along a vertical axis Y relative to the first carriage and to this end having horizontal slides such as  48  inside which slide horizontal rails such as  49  extending along the first carriage, and   a horizontal upper table  50  on the front portion of which are disposed horizontal slides such as  54  extending along the axis Y.       

     This bending machine also comprises a third carriage  51  able to slide horizontally along the horizontal axis Y relative to the upper table  50  of the second carriage  46  and including a horizontal plate  52  on the undersurface of which are provided horizontal rails such as  53  able to slide in slides  54  provided on the upper table  50  of the second carriage  46 . 
     This third carriage  51  also includes two parallel vertical plates  55 ,  56  on the horizontal plate  52 , each provided toward its upper end with a slide  57  that extends horizontally along an axis X perpendicular to the axis Y and thus parallel to the axis (x) of movement of the profile P. 
     Each of these slides  57  is adapted to house a sliding rail  58  for supporting a guide rule  59 ,  60 , each of said rules including two superposed grooves such as  60   a ,  60   b  with different sections adapted to house profiles with different sections. 
     The tool of this bending machine consists of three clamping forms  62 ,  63 ,  64  of identical design to the clamping forms  18 ,  19  described hereinabove, i.e. clamping forms of which each junction face has two rectilinear grooves with a longitudinal axis perpendicular to the bending radius between which extends a peripheral rebate. These clamping forms consist of:
         an intermediate clamping form  62  having two opposite junction faces: an upper junction face  65   a  and a lower junction face  66   a,      an upper clamping form  63  having a lower junction face  63   a  adapted to cooperate with the upper junction face  65   a  of the intermediate clamping form  62 , and   a lower clamping form  64  having an upper junction face  64   a  adapted to cooperate with the lower junction face  66   a  of the intermediate clamping form  62 .       

     Moreover, to enable bending of profiles P with different sections, the grooves such as  67   a ,  67   b  and the rebates such as  68   a ,  68   b  formed on the junction face  63   a  of the upper clamping form  63  and the upper junction face  65   a  of the intermediate clamping form  62  have dimensions different from those of the grooves such as  69   a ,  69   b  and the rebates such as  70   a ,  70   b  provided in the junction face  64   a  of the lower clamping form  64  and the lower junction face  66   a  of the intermediate clamping form  62 . 
     As before, these three clamping forms  62 - 64  are adapted:
         to move in translation relative to each other along the bending axis (z) between a spaced-apart position of the junction faces  63   a - 65   a ,  64   a - 66   a  for introducing and removing a profile P and a joined position for bending said profile, and   to be driven in simultaneous rotation in the position with the junction faces  63   a - 65   a ,  64   a - 66   a  joined.       

     To this end, and firstly, the lower clamping form  64  is fixed in terms of movement in translation along the bending axis (z) and rests on a fixed horizontal friction ring  71 . 
     Moreover, spring means such as two coil springs  72 ,  73  are disposed between the respective junction faces  63   a - 65   a ,  64   a - 66   a  of the clamping forms to spring-load the intermediate clamping form  62  and the upper clamping form  63  toward their spaced-apart position. 
     The clamping forms  62 - 64  are held in their joined position by means of a vertical shaft  74  that extends along the bending axis (z), is engaged in the openings  23  provided in said clamping forms and has ribs  75  conjugate with the splines  24 , said shaft having:
         an upper end including a member for limiting movement in translation of the upper clamping form  63 , consisting in this example of a nut  76 ,   a lower end constrained to move in translation with the vertically-arranged rod  78   a  of an actuator  78  the body of which is disposed on the lower table of a stirrup-shaped part  79  connected to the upper table  50  of the second carriage  46 , said actuator being adapted:
           in its deployed position, to allow the intermediate clamping form  62  and the upper clamping form  63  to be moved toward their spaced-apart position by the springs  72 ,  73 , and   in its retracted position, to exert a clamping force to hold the junction faces  63   a - 65   a ,  64   a - 66   a  of the clamping forms  62 - 64  joined.   
               

     Moreover, this shaft  74  is driven in rotation by a gearmotor  77   a ,  77   b  carried by the second carriage  46  under its upper table  50 . 
     According to this principle, the rotary shaft  74  has the functions of indexing the relative position in rotation of the three clamping forms  62 - 64  and holding said clamping forms in their joined position against the action of the spring means  72 ,  73 . 
     Note further that in this second embodiment the change of bending direction is effected by virtue of the facility for movement of the tool relative to the profile P along the axes Y and Z. 
       FIG. 8  shows a variant of this second embodiment in which, firstly, the third carriage  51  carries a single vertical plate  80  the upper end of which forms a horizontal rail  84  extending along the axis X. 
     Moreover, in this variant the two rules are produced from a single rectangular parallelepiped-shaped block  81  machined to have:
         in planes parallel to the plane (X, Z), two opposite vertical faces  82 ,  83  in each of which are formed two superposed grooves  82   a - 82   b ,  83   a - 83   b , respectively, with different sections, adapted to house profiles with different sections, and   a lower face in which is produced a slide  85  adapted to house the rail  84 .       

     In this variant, the rules  82 ,  83  are produced in a single block  81  carried by a single carriage  80  the movement of which requires only one guide and only one feed control system, instead of the two guides and the two control systems required for present-day machines enabling bending in two directions. 
     It is to be noted that this variant can also be implemented on a bending machine conforming to the first embodiment subject to providing that machine with means for moving the first carriage  3  along an axis Z. 
       FIGS. 9   a  to  9   d  show the operation of a bending machine as represented in  FIG. 1  when bending a profile P equipped with a nut E at its end. 
     Firstly, the angular position of the clamping forms  18 ,  19  is indexed to make the axis (x) coincide with the longitudinal axis of the pair of grooves appropriate for the selected bending direction, in this example the grooves  21   a - 21   b  (see  FIG. 9   a ). 
     Bending is then effected, in conjunction with the corresponding rule  17 , by rotating the two clamping forms  18 ,  19  about the bending axis (z) in the joined position of said clamping forms (see  FIG. 9   b ). 
     As shown in  FIGS. 9   c  and  9   d , bending in the opposite bending direction is effected in the same manner using the other pair of grooves, in this example the grooves  20   a ,  20   b , in conjunction with the other rule  16 , and, in this example, produces a bending angle greater than 180°. 
     This illustration highlights one of the essential advantages of the bending machine of the invention, namely the possibility of producing bending angles greater than 180° in both bending directions.