Abstract:
The invention relates to a forming head ( 300 ) which shapes a raw material ( 6 ) to spirally seamed tube ( 2 ), whereby the internal profile of the forming head ( 300 ) is U-shaped, the forming head ( 300 ) has an inlet side and an outlet side and there are on the upper side of the legs ( 306, 308 ) of said U shape slide surfaces ( 312, 314 ) for the raw material ( 6 ) passing through said forming head ( 300 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a forming head, a tube manufacturing unit with said forming head, and use of such a system for manufacture of spirally seamed tubes. 
       BACKGROUND 
       [0002]    Manufacture of spirally seamed tubes involves the use of a tube manufacturing device. Such a tube manufacturing device is fed with a continuous metal strip which is shaped before it enters the device. The tube manufacturing device is provided with a forming head which is adapted to the shape of the metal strip. When the strip runs through the forming head, the spiral shape is thus imparted. Together with the forming head, the tube manufacturing device comprises an element adapted to putting the edge portions of the strip together to constitute the spirally formed tube. This process and feeding of metal strip to the forming head take place continuously and the feed direction of the tube is parallel with the longitudinal direction of the tube. 
         [0003]    As mentioned above, in the state of the art, the forming head is adapted according to how the metal strip is configured. This means that for the strip to run consistently when entering the forming head and leaving the forming head, the forming head has to be so configured that it can receive the configured strip. However, this limits how the user can configure the strip. Accordingly, a different configuration of the metal strip will also mean that the forming head has to be replaced for being adapted to the new configuration. 
       SUMMARY OF THE INVENTION 
       [0004]    An object of the present invention is to achieve a forming head adapted to receiving a running metal strip which comprises various types of configurations. 
         [0005]    Another object of the invention is to overcome said problems of the state of the art. 
         [0006]    A further object of the invention is to propose a device and a method which are cost-effective as compared with traditional technology, which device is easy to construct, making it possible to optimise cost and time. 
         [0007]    The aforesaid and other objects are achieved according to the invention by the device described in the introduction being provided with the features arising from claim  1 . 
         [0008]    An advantage afforded by a device according to claim  1  is that the U-shaped profile can receive a running metal strip with a plurality of different configurations without need for replacement of forming head. 
         [0009]    Preferred embodiments of the device according to the invention are further provided with the features indicated by dependent claims  2 - 7 . 
         [0010]    According to an embodiment of the invention, the inlet side and the outlet side of the forming head have said U profile, with the effect that the metal strip runs more consistently through the forming head, in which the legs of the U profile are contact surfaces, i.e. slide surfaces on which the strip runs, i.e. slides, during its whole travel through the forming head. 
         [0011]    According to a further embodiment of the invention, said U profile comprises two legs linked together by a web, the width of said web being greater than the width of the legs. This makes it possible to choose from a plurality of variant configurations of the metal strip which run through the forming head. 
         [0012]    According to a further embodiment of the invention, said U profile comprises two legs linked together by a web, the width of said web being greater than the height of the legs, with the effect that the height of said legs controls the height of the desired configuration of the metal strip so that said strip runs through the forming head in contact with said legs. 
         [0013]    According to a further embodiment, the invention relates to a tube manufacturing unit comprising the forming head in accordance with the above. 
         [0014]    According to a further embodiment, the invention relates to a system comprising a tube manufacturing unit in accordance with the above and a tube cutting unit. 
         [0015]    According to a further embodiment, the invention relates to use of the system as above. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    A preferred embodiment of the device according to the invention is described below in more detail with reference to the attached schematic drawings, which only depict the parts which are necessary for understanding the invention. 
           [0017]      FIG. 1  depicts a tube manufacturing device with forming head, cutting unit and a continuous metal strip which is fed from a feed device. 
           [0018]      FIG. 2  depicts a tube manufacturing device with forming head, cutting unit and tube being made. 
           [0019]      FIG. 3  depicts a perspective view of the forming head. 
           [0020]      FIG. 4  depicts the inlet and the profile of the forming head. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0021]      FIG. 1  depicts a tube manufacturing device  1  for manufacture of spirally formed tube  2 . The tube manufacturing device  1  comprises a forming head  300  and a cutting unit  400 . A continuous metal strip  6  is fed, from a feed device  7  comprising the strip  6 , to the tube manufacturing device  1  via a shaping mill  8  provided with powered rollers. When the strip  6  passes through the shaping mill  8 , the powered rollers provide the strip  6  with desired correction and/or curvature. From the shaping mill  8 , the processed strip  6  is led towards the forming head  300  disposed on the tube manufacturing device  1 . The shaping mill  8  is preferably situated in the immediate vicinity of the tube manufacturing device  1  in such a way that they are connected to one another. The strip  6  is shaped by the forming head  300  to constitute a tube  2  which leaves the forming head  300  in a feed direction  316 . 
         [0022]      FIG. 2  depicts a tube manufacturing device  1  according to  FIG. 1  for manufacture of spirally formed tube  2 . The tube manufacturing device  1  comprises the forming head  300  and the cutting unit  400 . The cutting unit  400  comprises a knife holder  402  adapted to being movable towards the tube  2  to cutting position before cutting of the tube takes place. This direction is called the cutting direction  458 . The continuous metal strip  6  running from a feed device  7  via the shaping mill  8  and the latter&#39;s powered rollers is led towards the forming head  300  disposed on the tube manufacturing device  1 . As mentioned above, the shaping mill  8  is preferably situated in the immediate vicinity of the tube manufacturing device  1  in such a way that they are connected to one another. Their being connected to one another thus makes it possible for the strip  6  to be led into the tube manufacturing device  1  in an unvarying manner. This means that the manufacturing process need not be interrupted for adjustment of the way the strip  6  enters the tube manufacturing device  1 . 
         [0023]      FIG. 3  depicts the forming head  300  adapted to receiving the strip  6  at an inlet side in the form of an inlet  302  to the forming head  300 . In a cross-section through the forming head  300 , the inlet  302  is U-shaped (as depicted in  FIG. 4 ) and comprises a web  304 . The U shape comprises a first leg  306  and a second leg  308  each disposed on its respective side of the web  304 . The respective legs  306  and  308  each have a surface which faces towards a centreline  310  extending through the forming head  300 . The surface of the first leg  306  is called the first slide surface  312 . The surface of the second leg  308  is called the second slide surface  314 . The strip  6  fed in via said inlet  302  to the forming head  300  is led in a looplike movement along the slide surfaces  312  and  314 . After the strip  6  has undergone approximately one revolution inside the forming head  300 , one edge region  342  of the strip  6  meets the other edge region  352 . A pressing element situated at the junction between the edge regions  342 ,  352  continuously seams the respective edge regions together, resulting in a spiral shape which constitutes the tube  2 . The forming of a tube  2  thus takes place in the forming head  300 . The finished tube  2  leaves the forming head  300  at an outlet side in the form of an outlet  303  in a feed direction  316  which is parallel to the centreline  310  of the forming head  300 . 
         [0024]    The forming head  300  including a U-shaped profile is adapted to receiving various configurations of the metal strip  6  which can be imparted by the shaping mill  8 . This is depicted in the form of a piece of strip in  FIG. 4 . The configurations are only limited by the width of said web  304  and the height of said legs  306 ,  308 . For example, the strip may be provided with any desired number of corrugations  372 . 
         [0025]    The invention is not limited to the embodiment depicted but may be varied and modified within the scope of the claims set out below, as partly described above. 
       REFERENCE NOTATIONS 
       [0000]    
       
           1 . tube manufacturing device 
           2 . tube (spirally formed) 
           6 . metal strip 
           7 . feed device 
           8 . shaping mill 
           300 . forming head 
           302 . inlet 
           303 . outlet 
           304 . bottom 
           306 . first leg 
           308 . second leg 
           310 . centreline 
           312 . first slide surface 
           314 . second slide surface 
           316 . feed direction 
           342 . first edge region 
           352 . second edge region 
           372 . corrugations 
           400 . cutting unit 
           402 . knife holder 
           458 . cutting direction