Tube bending machine with an automatic loading system and method for automatic loading of tubes on the bending head of a tube bending machine

Abstract

The machine includes: a bending head movable with at least two degrees of freedom in a transverse vertical plane; a first drive is arranged to move the bending head in the plane and to move a tool of the bending head between an open position, in which it defines with a die of the bending head a free space adapted to receive a tube to be bent, and a closed position, in which it clamps the tube against the die. A tube-carrying structure is rotatable about an axis of rotation perpendicular to the plane; a second drive is arranged to cause the tube-carrying structure to rotate about its own axis of rotation; and an electronic control unit is arranged to control the first and second drives so as to move the bending head and the tube-carrying structure in a position such that the tube is received with a desired orientation in the free space between the die and the tool.

1 . Tube bending machine for bending tubes or similar elongated blanks, such as profiled sections and bars, the machine comprising:
 a bending head movable with at least two degrees of freedom in a transverse vertical plane, the bending head being provided with a clamping fixture able to take alternatively an open position, in which the clamping fixture defines a free space such as to allow a tube to be bent to be inserted therein, and a closed position, in which the clamping fixture clamps the tube previously inserted into said free space;   first driving means arranged to move the bending head in said transverse vertical plane and to move the clamping fixture between said open and closed positions;   a tube-carrying structure rotatable about a first axis of rotation perpendicular to said transverse vertical plane;   second driving means arranged to rotate the tube-carrying structure about said first axis of rotation between an initial position, in which the tube-carrying structure is able to receive the tube, and a final position; and   an electronic control unit arranged to calculate an initial position of the bending head and a final position of the tube-carrying structure such that the tube carried by the tube-carrying structure is located with a desired orientation in the free space of the clamping fixture, and to control said first and second driving means so as to move the bending head in said transverse vertical plane until the bending head reaches the respective calculated initial position, so as to cause the tube-carrying structure to rotate about said first axis of rotation from the respective initial position to the respective calculated final position, and so as to clamp the tube by the clamping fixture once the bending head and the tube-carrying structure are positioned in the calculated initial and final positions, respectively.   
     
     
         2 . Tube bending machine according to  claim 1 , further comprising a body on which the bending head is rotatably mounted about a second axis of rotation parallel to said first axis of rotation, the body being able to translate along a horizontal direction perpendicular to said first and second axes of rotation. 
     
     
         3 . Tube bending machine according to  claim 1 , wherein the bending head carries a bending fixture including a die and a tool movable relative to the die, and wherein the clamping fixture is formed by the bending fixture, wherein said free space is defined between the die and the tool of the bending fixture. 
     
     
         4 . Tube bending machine according to  claim 3 , wherein the bending head carries two bending fixtures, each of the bending fixtures comprising a die and a tool and are arranged to carry out the one a right-hand bending operation and the other a left-hand bending operation, and wherein said first driving means are arranged to bring either of the clamping fixtures into the calculated initial position to clamp the tube carried by the tube-carrying structure between the die and the tool of that bending fixture. 
     
     
         5 . Tube bending machine according to  claim 1 , wherein the tube-carrying structure comprises at least one pair of arms rotatable about said first axis of rotation, each arm having in a free end portion thereof a seat for receiving a tube. 
     
     
         6 . Tube bending machine according to  claim 5 , wherein each arm of the tube-carrying structure comprises a locking member movable between an open position, in which the locking member allows the tube to be inserted into the seat and to be drawn out of the seat, and a closed position, in which the locking member locks the tube within the seat. 
     
     
         7 . Tube bending machine according to  claim 1 , further comprising a loading device arranged to load a tube on the tube-carrying structure when the tube-carrying structure is in the initial position, the loading device comprising an inclined plane the inclination of which is such as to allow a tube arranged thereon to fall towards the tube-carrying structure. 
     
     
         8 . Tube bending machine according to  claim 1 , wherein the tube-carrying structure is spaced from the transverse vertical plane so as not to interfere with the movement of the bending head in said plane and is provided with feeding means arranged to urge the tube towards the bending head. 
     
     
         9 . Method for automatically loading a tube or a similar elongated blank, such as a profiled section or a bar, on a bending head of a tube bending machine, said bending head being movable with at least two degrees of freedom in a transverse vertical plane and being provided with a clamping fixture which is able to take alternatively an open position, in which the clamping fixture defines a free space such as to allow a tube to be bent to be inserted therein, and a closed position, in which the clamping fixture clamps the tube previously inserted into said free space, the method comprising the steps of:
 a) arranging and locking the tube on a tube-carrying structure, the tube-carrying structure is rotatable about an axis of rotation perpendicular to said transverse vertical plane; 
 b) rotating the tube-carrying structure about said axis of rotation and moving the bending head in said transverse vertical plane until the bending head reaches a position such that the tube is placed with the desired orientation in the free space defined by the clamping fixture; 
 c) clamping the tube by the clamping fixture of the bending head; 
 d) disengaging the tube from the tube-carrying structure; and 
 e) moving the tube by the bending head in a position such that the tube can be clamped by clamping means carried by a body of the tube bending machine. 
 
     
     
         10 . Method according to  claim 9 , further comprising, between steps b) and c), the step of urging the tube towards the bending head and, between steps d) and e), the step of moving the tube-carrying structure away from the bending head in a position such that the tube-carrying structure does not interfere with the bending head.