Abstract:
A shearing device of an extrusion press for cutting off a discard includes a first drive device; a means for converting rotational motion generated by the first drive device to linear motion; a shearing-slide drive frame caused to move linearly by the means for converting rotational motion to linear motion, which shearing-slide drive frame is coupled to a shearing slide to which a shearing blade is fixed; a slide part coupled with the shearing-slide drive frame through a link unit; and a second drive device causing the slide part move linearly to cause the shearing-slide drive frame move linearly, wherein the first drive device and the second drive device are arranged in parallel with the means for converting rotational motion to linear motion.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a shearing device in an extrusion press for extruding an aluminum alloy or other metal in which the shearing device makes a container separate from a die after extrusion and cuts off a remainder of a billet, that is, a discard, at a front surface of the die to thereby cut it off from an extruded product part. 
       BACKGROUND ART 
       [0002]    In a conventional shearing device of an extrusion press, a shearing cylinder for cutting off the discard is attached facing downward to a frame provided at a container side of a top part of an end platen holding the die and a shearing blade is provided through a shearing slide at the bottom end part of a piston rod of the shearing cylinder. 
         [0003]    In a conventional extrusion press, an electric powered shearing device used a single long ball screw for a drive device and further had a motor for driving the ball screw arranged at a top side of the ball screw. For this reason, the shearing device as a whole became higher in height and it is necessary to raise the height of the building etc. Furthermore, in an extrusion press with a drive device comprised of a hydraulic cylinder, the hydraulic cylinder is attached on top of the shearing slide with the shearing blade, the shearing guide, and the shearing frame. If including the length of the cylinder rod, the height became considerable. 
       CITATION LIST 
     Patent Literature 
       [0004]    PLT 1: Japanese Patent Application Publication No. 2013-244509A 
       SUMMARY OF INVENTION 
     Technical Problem 
       [0005]    In a conventional type of extrusion press, there are the following problems. 
         [0006]    In a conventional type of extrusion press, an electric powered shearing device used a single long ball screw for a driving means and further had a motor for driving a ball screw arranged at the top side of the ball screw. 
         [0007]    Further, a hydraulic cylinder is used for a drive device, so the shearing device as a whole became higher in height and the height of the building etc. had to be raised. 
       Solution to Problem 
       [0008]    According to the present invention, there is provided a shearing device of an extrusion press for cutting off a discard, the shearing device of an extrusion press comprising a first drive device, a means for converting rotational motion generated by the first drive device to linear motion, a shearing-slide drive frame made to move linearly by the means for converting rotational motion to linear motion, which shearing-slide drive frame is coupled to a shearing slide to which a shearing blade is fixed, a slide part coupled with the shearing-slide drive frame through a link unit, and a second drive device making the slide part move linearly to make the shearing-slide drive frame move linearly, the first drive device and the second drive device being arranged in parallel with the means for converting rotational motion to linear motion, 
         [0009]    In the present invention, the second drive device may be comprised of a motor, and the shearing device of the extrusion press may further comprise a second means for converting rotational motion generated by the motor to linear motion. 
         [0010]    In the present invention, the second drive device may be comprised of a hydraulic cylinder. 
         [0011]    In the present invention, power causing descending motion of the shearing slide before cutting the discard may be generated by the first drive device, a large part of power causing descending motion of the shearing slide cutting the discard by the shearing blade may be generated by the second drive device, and power causing ascending motion of the shearing slide after cutting off the discard by the shearing blade may be generated by the first and second drive devices. 
         [0012]    In the present invention, the hydraulic cylinder may be operated by a fire-resistant hydraulic fluid. 
       Advantageous Effects of Invention 
       [0013]    Compared with a conventional shearing device, the stroke of the shearing blade is the same, but by dividing a drive device into two (first and second) devices, and by arranging the drive devices in parallel, it is possible to greatly lower the height of the device, so the building can be lowered. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0014]      FIG. 1A  is a front view of a shearing device of a first embodiment of the present invention. 
           [0015]      FIG. 1B  is a side view of the shearing device shown in  FIG. 1A . 
           [0016]      FIG. 1C  is a plan view of the shearing device shown in  FIG. 1A . 
           [0017]      FIG. 2  are views of operation of the shearing device of the first embodiment of the present invention by front views. 
           [0018]      FIG. 3  are views of operation of a shearing device of a second embodiment of the present invention by front views. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0019]    Embodiments of the shearing device according to the present invention will be explained in detail below while referring to the drawings. 
         [0020]      FIGS. 1A, 1B, and 1C ,  FIG. 2 , and  FIG. 3  will be used to explain embodiments of the present invention. In  FIGS. 1A, 1B, and 1C , reference notation  11  indicates an end platen,  12  a die stack,  13  a die block,  14  a guide member for guiding movement in a horizontal direction perpendicular to a back surface of the die block  13 , and  15  is a pressure ring inside the end platen receiving pressing force from the die stack  12 . At the center parts of the pressure ring  15  and end platen  11 , a hole is provided for passage of a product extruded from the die stack  12 . Note that, the die stack  12  is comprised of a not shown plurality of parts. 
         [0021]    At the top container side of the end platen  11  holding the die stack  12  at its front surface side, a shearing frame  27  is attached. At part of the shearing frame  27 , a shaft  19  is used to attach a shearing slide  18  housed inside of a shearing guide  9  to be able to rotate in extrusion and anti-extrusion directions. Reference notation  7  is a shearing blade for cutting off a discard. Reference notation  18  is the shearing slide. The shearing blade  7  is attached to the shearing slide  18 . Between the shearing blade  7  and the shearing slide  18 , there is a not shown shim for adjusting the clearance between the cutting surface of the die stack  12  and the shearing blade  7 . Further, reference notation  10  is a container in which a billet is inserted. 
         [0022]    The die stack  12  is housed in a die block  13 . A die set comprised of the die stack  12  and die block  13  is pushed in the direction of the end platen, so that the movement in the horizontal direction of the die set is restricted between a pressure ring  15  and horseshoe  17 . By this configuration, the die stack  12  is fastened to the end platen  11  by a die stack horizontal fastening cylinder through a not shown horizontal direction arm. 
         [0023]    Simultaneously, a not shown vertical die clamp may be used to push the die stack  12  and fasten it in the vertical direction as well. The vertical die clamp operates by a die stack vertical fastening cylinder. 
         [0024]    Referring to  FIGS. 1A and 1B , the surface of the bottom end of the shearing guide  9  at the die stack side pushes against the container side end face of the horseshoe  17  by a not shown swing cylinder for the shearing slide. 
         [0025]    By fastening in this way, the relative position of the horseshoe  17  and the shear face side of the die stack  12  can be maintained constant at all times. Even if in the middle of cutting off the discard after extrusion, due to this pressing action in the horizontal direction and pressing action in the vertical direction, the die stack  12  can be maintained at the same position at all times without moving. 
         [0026]    The shearing slide  18  is housed inside the shearing guide  9 . By a not shown shearing-slide swinging cylinder swinging about a not shown pin, the shearing guide  9  swings about the pin. By being driven by the motor, the shearing slide  18  slides up and down inside the shearing guide  9 . Due to this, the shearing blade  7  is made suitable in distance from the die stack  12 . 
         [0027]    The first embodiment will be further explained with reference to  FIGS. 1A, 1B, and 1C  and  FIG. 2 . 
         [0028]    First, the stroke of the shearing blade  7  of the shearing device of the present invention, as will be understood from  FIG. 2 , includes the two strokes of a first stroke of the shearing blade  7  attached to the shearing slide  18  descending until contacting the discard (in  FIG. 2 , range of reference notation A) and a second stroke of cutting off the discard (in  FIG. 2 , range of reference notation B). In the first stroke, the first drive device is operated, while in the second stroke, the first and second drive devices are simultaneously operated. In the present embodiment, the first drive device is configured by a first motor  21 , while the second drive device is configured from a second motor  33 . 
         [0029]    In the first stroke, the first motor  21  attached to the shearing frame  27  is operated. An output shaft of the first motor  21  and an end part of a ball screw  23  are connected by a timing belt. The first motor  21 , for example, may be a servo motor or such. If the first motor  21  is used to make the ball screw  23  turn, a shearing-slide drive frame  26  formed integrally with a ball nut  24  descends. 
         [0030]    One end of the shearing-slide drive frame  26  is coupled with the shearing slide  18  by a pin  19  and simultaneously coupled at the other end with the one end of each of link units  25 . Furthermore, the other end of each of the link units  25  is coupled with the slide part  31 . In the present embodiment, a converting means for converting rotational motion to linear motion is explained as the ball screw  23  and ball nut  24 , but may also be a rack and pinion or such. 
         [0031]    At the time of start of the shearing operation, the link units  25  are folded up in state ( FIG. 2( a ) ). If the shearing-slide drive frame  26  starts to descend, the link units  25  open. As shown in  FIG. 2( b ) , if the shearing-slide drive frame  26  descends until the link units  25  become the substantially straight state, the shearing-slide drive frame  26  is configured to fall in speed. 
         [0032]    In the second stroke, the second motor  33  attached to the shearing frame  27  while facing vertically downward is driven. The second motor  33  may, for example, be a servo motor or such as well. Further, the method of attachment is not limited to facing vertically downward. A first pulley  34  of the output shaft of the second motor  33  and two second pulleys  38  are connected by a belt  36 . The two second pulleys  38  and two third pulleys  35  of the two ball screws  32  are respectively connected by belts  41 . The belts may, for example, be timing belts or such. By such a configuration, the servo motor comprising the second motor  33  can drive the two ball screws  32  synchronized. Note that, the ball screws  32  and the ball nuts  42  combined with these act as second converting means for converting rotational motion to linear motion. 
         [0033]    Due to the drive operation of the second motor  33 , the two ball screws  32  turn and the slide part  31  connected with the ball nuts  42  is made to descend.  FIG. 2( b )  shows the state when the shearing blade  7  has just contacted the discard  8 . If operating the second motor  33  to make the slide part  31  descend from this state, force is transmitted to the discard from the slide part  31  through the two link units  25 , shearing slide  18 , and shearing blade  7 . If further making the slide part  31  descend and reaching the state of  FIG. 2( c ) , the discard  8  is cut off. 
         [0034]    Further, the first motor  21  driving operation in the first stroke continues to drive operation in the second stroke as well and simultaneously the second motor  33  drives operation to track the second stroke. In the present embodiment, the power generated by second motor  33  is far larger than the power generated by the first motor  21 . Therefore, the majority of the power required for the second stroke is supplied from the second motor  33 . After the discard finishes being cut off, to make the shearing slide  18  etc. return to their initial positions at a high speed, the first and second drive motors  21  and  33  are simultaneously driven in opposite directions to the time of descent. 
         [0035]    The first stroke shown by reference notation A in  FIG. 2  is a stroke where no load is applied to the shearing blade  7  and where the shearing blade  7  can move at a high speed by a low output, while the second stroke shown by reference notation B is a stroke where a load is applied to a shearing blade  7  and where the shearing blade  7  can move at a low speed by a high output. The entire stroke is C=A+B. 
         [0036]    Breakage or slack of the belt  36  and belt  41  are detected by not shown proximity sensors or are detected by the load current of the second motor  33 . If the belt  36  and belt  41  breaks or becomes slack, not shown electromagnetic brakes attached to the end faces of the ball screws are operated so as to be able to prevent in advance a drop in the slide part  31  downward. 
         [0037]    The electromagnetic brake operates electrically. When electric power is turned on, it opens, while when electric power is cut off, the brake is applied. 
         [0038]    A second embodiment will be explained with reference to  FIG. 3 . In the second embodiment, the first drive device is configured by a motor  21  (not shown), while the second drive device is configured by hydraulic cylinders  51 . In the first stroke, the motor  21  attached to the shearing frame  27  is operated. The output shaft of the motor  21  and the end part of the ball screw  23  are connected by a belt. The motor  21  may be, for example, a servo motor. If the motor  21  is used to make the ball screw  23  turn, the shearing-slide drive frame  26  formed integrally with the ball nut  24  descends. Note that, in  FIG. 3 , the motor  21  is not shown, but the motor  21  is arranged in the same way as the first motor  21  in the first embodiment shown in  FIG. 1( b ) . 
         [0039]    One end of the shearing-slide drive frame  26  is coupled by the pin  19  with the shearing slide  18  and, simultaneously, the other end is coupled with one end of each of link units  25 . Furthermore, the other end of each of the link units  25  is coupled with a slide part  53 . 
         [0040]    At the point of time of the start of a shearing operation, the link units  25  are folded up in state ( FIG. 3( a ) ). If the shearing-slide drive frame  26  starts to descend, the link units  25  open. As shown in  FIG. 3( b ) , if the shearing-slide drive frame  26  descends until the link units  25  become the substantially straight state, the shearing-slide drive frame  26  is configured to fall in speed. 
         [0041]    In the second stroke, the two hydraulic cylinders  51  make the slide parts  53  descend.  FIG. 3( b )  shows the state where the shearing blade  7  just contacts the discard  8 . If driving the hydraulic cylinders  51  to make the slide parts  53  descend from this state, force is applied to the discard from the slide parts  53  through the two link units, shearing slide  18 , and shearing blade  7 . If the slide parts  53  are made to further descend to the state of  FIG. 3( c ) , the discard  8  is cut off. 
         [0042]    The motor  21  is operated even during the second stroke so as to track the shearing-slide drive frame  26 . 
         [0043]    For the two slide parts  53 , a not shown pipe-shaped guide may be provided. 
         [0044]    For the hydraulic fluid of the hydraulic cylinders  51 , in the present embodiment, for example, a fire-resistant hydraulic fluid such as a water-glycol fluid is used. 
         [0045]    The first stroke shown by the reference notation D in  FIG. 3  is a stroke in which the shearing blade  7  can move at a high speed by a low output in the stroke of a load being not applied to the shearing blade  7 , while the second stroke shown by the reference notation E is a stroke in which the shearing blade  7  can move at a low speed by a high output in the stroke of a load being applied to the shearing blade  7 . The strokes are F=D+E. 
         [0046]    After cutting off the discard, the shearing slide  18  etc. are made to return to their initial positions at a high speed by making both the drive motor  21  and hydraulic cylinders  51  operate in the opposite direction to the time of descent. 
         [0047]    The present invention has the following effects due to being configured in the above way. 
         [0048]    Compared with a conventional shearing device, the stroke of the shearing blade is the same, but two (first and second) drive devices are provided and arranged at the side of the ball screw  23  or shearing-slide drive frame  26 , that is, in parallel with the ball screw  23  or shearing-slide drive frame  26 , so as to greatly lower the height of the device, so the building can be lowered. 
         [0049]    In the second embodiment, the hydraulic fluid of the hydraulic cylinder is a fire-resistant hydraulic fluid such as a water-glycol fluid, so even if the fluid leaks, it is possible to lighten the risk of fire at the time of operation or maintenance. 
         [0050]    Further, even if, like in second embodiment, using hydraulic cylinders for the second drive device, this is used only when cutting off the discard, so the amount of hydraulic fluid can be greatly cut and resource saving and energy saving can be contributed to. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           7 . shearing blade 
           8 . discard 
           9 . shearing guide 
           11 . end platen 
           12 . die stack 
           13 . die block 
           14 . guide member 
           17 . horseshoe 
           18 . shearing slide 
           20 . shearing device 
           21 . first motor 
           22 . belt 
           23 . ball screw 
           24 . ball nut 
           25 . link unit 
           26 . shearing-slide drive frame 
           27 . shearing frame 
           31 . slide part 
           32 . ball screw 
           33 . second motor 
           34 . first pulley 
           35 . third pulley 
           36 . belt 
           38 . second pulley 
           41 . belt 
           42 . ball nut 
           51 . hydraulic cylinder 
           52 . cylinder rod 
           53 . slide part