Abstract:
The present invention relates to a machine for bending a material having the shape of a wire as a tube having vertical movement of the spar by the use of a pantograph lifting device, advantageously reducing the number of devices used for lifting of said spar and advantageously increasing the lateral stiffness of the machine.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a machine for bending a material having the shape of a wire as a tube having a vertical movement of the spar by the use of a pantograph lifting device, advantageously reducing the number of devices used for lifting said spar and increasing the lateral stiffness of the machine. 
       STATE OF THE ART 
       [0002]    It is known, the machine for bending of a material having the shape of a wire, such as the tube, it is equipped with a spar on which a positioner of the material having the shape of a wire is installed to be bent, hereinafter named tube, a core pull for said tube, the bending head placed at one end of said spar. 
         [0003]    To proceed to bend the tube by the bending head equipped with appropriate means, the tube to be bent, housed in the positioned, must be placed in a given position with respect to the bending head. This placement has obtained moving the spar vertically: for clarity, the applicant brings out that the above vertical direction of the spar has to be identified with respect to the surface on which the whole machine is placed obviously. The known bending machines perform this movement by using a large number of devices. 
         [0004]    Said known bending machines solve the problem of moving the spar vertically with a vertical wall equipped with special devoted lifting devices of the spar. These lifting devices are positioned on the wall and they hook the spar lifting it at the desired quota. Other machines known solve the same problem by some U-shaped structures, at least two, also equipped with lifting devices of the spar. 
         [0005]    According to this other known solution, the spar under reference is placed into said U structures and it is lifted to the desired quota by the lifting means of which the U structures are equipped. 
         [0006]    Known handling systems of the spar have the inconvenience of having to employ a large number of devices to accomplish the aforementioned vertical movement of the spar. 
         [0007]    The large number of these devices has the disadvantage of the cracks and the difficulty of synchronizing the mentioned devices and also they have high costs. 
       DESCRIPTION OF THE INVENTION 
       [0008]    The present invention solves the problems of the prior art advantageously through the adoption of a pantograph-shaped device placed under the spar and it is suitable to move said spar vertically. 
         [0009]    The handling device of the spar having pantograph shape, briefly hereinafter pantograph, it includes at least two couple of crossbars. The pairs of the crossbars are placed so as to form at least two parallel X, at least connected by a central pivot. The extremes of the parallel X, formed by the crossbars making up the pantograph are connected by at least two couple of pins each other parallel and also parallel to the surface on which the machine is placed. The pins placed near to the bending head of the machine have a limited mobility. Said pins have only vertical mobility and this mobility is reserved to the upper pins preferably and the lower pin cannot change quota. 
         [0010]    Rear pivots of the pantograph have also movement, in particular the lower pin can move only horizontally while upper pin has vertical and horizontal movement. 
         [0011]    The handling constraints to the mentioned pins of each pantograph advantageously allow to move the spar vertically without having it translated horizontally too, advantageously avoiding having to compensate for the position of the tube. 
         [0012]    The movement devices having the pantograph shape are usually driven by a hydraulic cylinder which pushes the extremes of said pantograph. This cylinder is controlled by a hydraulic station, but unfortunately this station is too bulky and therefore it is not favorable because it increases the area occupied by the machine in an unacceptable manner. 
         [0013]    To solve this problem, the pantograph object of the present invention is driven by a controlled axis pushing the extremity of the pantograph. This movement is accomplished by an electric motor that can be precisely controlled. Said motor is connected to a mechanical system of translation, preferably a screw. That screw can have a fine pitch to allow even micrometric movements. 
     
    
     
       DESCRIPTION OF FIGURES 
         [0014]      FIG. 1  shows a perspective view of the machine bending material having the shape of a wire, such as the tube that is the subject of the present invention which is at rest. 
           [0015]      FIG. 2  shows a perspective view of the machine for bending having the shape of a wire, such as the tube having a raised spar. 
       
    
    
       [0016]      FIG. 1  shows a perspective view of the entire machine ( 1 ) to bend material having the shape of a wire, such as the tube comprising a spar ( 2 ), a positioner ( 3 ), a core pull ( 4 ) for the tube, a bending head ( 5 ) and a device ( 6 ) to lift the spar ( 2 ) vertically. Said device ( 6 ) has the shape of a pantograph comprising two pairs of crossbars ( 7   1 ,  7   2  and  8   1 ,  8   2 ). The embodiment of  FIG. 1  shows two pairs of crossbars, but it is also part of the present invention to use a larger number of pairs of crossbars. 
         [0017]    Said pair of crossbars are placed in the way to form two parallel X, connected by a central pin ( 9 ). Said crossbars have the ends connected by a pair of parallel front pins ( 10   1 ,  10   2 ) and a rear pair of pins ( 11   1 ,  11   2 ). These pins have a limited mobility. 
         [0018]    The front pins ( 10   1 ,  10   2 ) have a mobility vertical only which is not represented graphically, preferably the upward mobility is reserved for upper pin ( 10   1 ) exclusively. 
         [0019]    The rear pair of pins ( 11   1 ,  11   2 ) has a movement, not represented graphically, the horizontal upper rear pivot ( 11   1 ) has also a vertical movement. 
         [0020]    The drive of the device ( 6 ) due to which the spar ( 2 ) is raised vertically it is given to a controlled axis ( 12 ) capable of pushing at least one rear pin ( 11   1 ) and/or ( 11   2 ). 
         [0021]    The controlled axis ( 12 ) includes an electric motor ( 13 ) controlled by a mechanical system of translation ( 14 ) preferably, which is a screw preferably. 
         [0022]    With reference to  FIG. 2 , the machine object of the present invention is represented in perspective after having lifted the spar ( 2 ) vertically. It is shown with dashed line the position of the device ( 6 ) having the shape of pantograph at rest and with solid line after the spar ( 2 ) has been lifted. In this figure the dashed line shows the positions of the front pairs of pins ( 10   1  and  10   2 ) and the rear pair of pins ( 11   1  and  11   2 ) with the device ( 6 ) having the shape of pantograph in the resting phase and the same pairs of pins represented by a solid lines after the spar ( 2 ) was raised vertically by the device ( 6 ).  FIG. 2  shows the movement of the pins to carry out this lifting: the upper front pin ( 10   1 ) has the movement vertically only, the lower front pin ( 10   2 ) has not changed its position, the upper rear pin ( 11   1 ) has moved both horizontally and vertically the below rear pin ( 11   2 ) has changed its position only horizontally.