Abstract:
There is provided a machine tool capable of housing workpieces of different sizes in a same workpiece storage unit without requiring a new workpiece storage unit. In a machine tool including a workpiece storage unit having a plurality of housing spaces housing workpieces and a processing machine processing a workpiece supplied from one of the housing spaces, the workpiece storage unit is structured so that the size of each housing space is changeable.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a machine tool including a processing machine processing a workpiece and a workpiece storage unit housing workpieces, and particularly relates to the sizes of workpiece housing spaces in the workpiece storage unit. 
         [0003]    2. Description of the Related Art 
         [0004]    As a workpiece storage unit of this type, for example, Japanese Patent No. 3047847 discloses one in which pallet storage shelves formed at plural levels in a vertical direction are arranged annularly circumferentially, and a carry arm capable of moving in the vertical direction, turning about a vertical axis, and moving in a horizontal direction is disposed in the center portion thereof. 
       SUMMARY OF THE INVENTION 
       [0005]    Incidentally, in the conventional workpiece storage unit, housing spaces formed by the pallet storage shelves are fixed in size, and thus the sizes of workpieces which can be housed are fixed as well. Therefore, when workpieces of different sizes are stored, there occurs a problem of requiring a new workpiece storage unit. 
         [0006]    It is an object of the present invention to provide a machine tool capable of housing workpieces of different sizes in a same workpiece storage unit without requiring a new workpiece storage unit. 
         [0007]    In a machine tool according to the present invention including a workpiece storage unit having a plurality of housing spaces housing workpieces and a processing machine processing a workpiece supplied from one of the housing spaces, the workpiece storage unit is structured so that the size of each housing space is changeable. 
         [0008]    According to the present invention, since the housing spaces of the workpiece storage unit are changeable, workpieces of different sizes can be housed in the same workpiece storage unit by changing the housing spaces in size according to the sizes of workpieces, thereby allowing to increase types of workpieces which can be housed. 
         [0009]    In a preferred embodiment of the present invention, the workpiece storage unit has a workpiece replacement device supplying a workpiece housed in one of the housing spaces to the processing machine and housing a workpiece processed with the processing machine in one of the housing spaces, and the size of each housing space is changed using the workpiece replacement device. 
         [0010]    According to the preferred embodiment, since the housing spaces are changed by the workpiece replacement device provided for replacing an unprocessed workpiece housed in one of the housing spaces with a processed workpiece, it is possible to change the housing spaces without providing a new housing space changing mechanism. 
         [0011]    In another preferred embodiment of the present invention, the workpiece storage unit has a plurality of support posts extending in a vertical direction and shelves disposed at plural levels on the support posts, at least a part of the shelves is removable, and the size of each housing space is changed by the workpiece replacement device attaching/removing the removable shelves to/from the support posts or moving the attaching position thereof in an upward or downward direction. 
         [0012]    According to another preferred embodiment, since the housing spaces are formed by disposing shelves at plural levels on the support posts and at least a part of the shelves is removable, and the housing spaces are changed by attaching/removing the removable shelf to/from the support posts or moving the shelf in an upward or downward direction using the workpiece replacement device, it is possible to change the housing spaces without complicating the structure of the entire machine. 
         [0013]    In still another preferred embodiment of the present invention, a workpiece detecting means for detecting the size of a workpiece which is supplied to the workpiece storage unit is provided, in which the workpiece replacement device houses the supplied workpiece in a housing space having a size corresponding to the size of the workpiece detected by the workpiece detecting means. 
         [0014]    According to still another preferred embodiment, since the workpiece detecting means for detecting the size of a workpiece which is supplied to the workpiece storage unit is provided, and the supplied workpiece is housed automatically by the workpiece replacement device in a housing space corresponding to the size of the workpiece detected by the workpiece detecting means, it is not necessary for the operator to specify the workpiece size by operating an operation board, thereby facilitating a workpiece supply operation to the workpiece storage unit. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  is an overall perspective view of a machine tool according to an embodiment of the present invention; 
           [0016]      FIG. 2  is a plan view of the machine tool; 
           [0017]      FIG. 3  is a perspective view of a workpiece replacement device of the machine tool; 
           [0018]      FIG. 4  is a plan view of a workpiece replacement arm when the arm is in a forward position; 
           [0019]      FIG. 5  is a side view of the workpiece replacement arm; 
           [0020]      FIG. 6  is a side view of the workpiece replacement arm when the arm is in a moved back position; 
           [0021]      FIG. 7  is a perspective view showing the state of a removable shelf arranged on support brackets; 
           [0022]      FIG. 8  is a side view of a preparation station; 
           [0023]      FIG. 9  is a plan view showing the state of the workpiece replacement arm and the shelf when the shelf is moved by the workpiece replacement device; 
           [0024]      FIG. 10  is a side view showing a state that a processed workpiece is being removed from a worktable of a processing machine; 
           [0025]      FIG. 11  is a side view showing a state that the processed workpiece is removed from the worktable; 
           [0026]      FIG. 12  is a plan view for describing an operation to house the processed workpiece on a shelf; 
           [0027]      FIG. 13  is a plan view for describing an operation to take an unprocessed workpiece off a shelf; 
           [0028]      FIG. 14  is a plan view for describing an operation to supply the unprocessed workpiece to the worktable of the processing machine; 
           [0029]      FIG. 15  is a perspective view showing a state that the removable shelf is being removed from the support brackets; 
           [0030]      FIG. 16  is a perspective view showing a state that the removable shelf is removed from the support brackets; and 
           [0031]      FIG. 17  is a perspective view showing a state that the removable shelf is attached to an upper bracket. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]    Hereinafter, an embodiment of the present invention will be described based on the attached drawings. 
         [0033]      FIG. 1  to  FIG. 17  are views for describing a machine tool according to the embodiment of the present invention. 
         [0034]    In the drawings, numeral  1  denotes a machine tool. This machine tool  1  includes a workpiece storage unit  2  storing a large number of workpieces  4 , and a processing machine  3  performing machine processing on a workpiece  4  supplied from the workpiece storage unit  2 . 
         [0035]    The processing machine  3  includes a worktable  3   b  on which the workpiece  4  is mounted, and a processing machine body  3   a  which performs various types of processing on the workpiece  4  mounted on the worktable  3   b . Incidentally, numeral  3   c  denotes a structure formed surrounding the circumference of the processing machine body  3   a  and the worktable  3   b.    
         [0036]    The workpiece storage unit  2  includes a storage device body  2   a  formed in a substantially cylindrical shape, and a workpiece replacement device  5  disposed in a center portion of the storage device body  2   a . The storage device body  2   a  has a plurality of support posts  7  disposed annularly circumferentially and extending in a vertical direction, shelves  6 - 1  to  6 - 10  at plural levels supported between adjacent support posts  7 ,  7 , and a preparation station  8  provided to be located at a machine front F. 
         [0037]    The shelves  6 - 1 ,  6 - 3 , . . . ,  6 - 9  at odd number levels out of the shelves  6 - 1  to  6 - 10  are fixed between the support posts  7 ,  7  via brackets  7   a , and the shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10  at even number levels are supported removably between the support posts  7 ,  7 . 
         [0038]    Specifically, front and rear support brackets  7   b ,  7   c  are fixed to the support posts  7 . The rear support brackets  7   c ,  7   c  support left and right rear portions  6 ′,  6 ′ of the shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10 , and the front support brackets  7   b ,  7   b  support left and right front portions  6 ″,  6 ″ of the shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10 . Further, a pin hole  7   d  is formed in each rear support bracket  7   c , in which a falling prevention pin  6   a  planted in the shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10  is inserted. Moreover, a positioning projection  7   e  is formed to project thereon, which engages with a positioning hole  6   c  formed in the shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10 . 
         [0039]    The preparation station  8  has a fixed table  8   a  supporting a rotary table  26 , and a rotary actuator  24  is disposed below the rotary table  26  of the fixed table  8   a . An output gear  24   a  of the rotary actuator  24  meshes with an input gear  26   a  of the rotary table  26 . A workpiece  4  is mounted on a pallet  23  mounted on the rotary table  26 , and the pallet  23  and the workpiece  4  are fastened by a bolt or the like while rotating the pallet  23  and the workpiece  4  by the rotary table  26 . Incidentally, the pallet  23  and the workpiece  4  may be fastened without rotating the rotary table  26  depending on the shape or the like of the workpiece. 
         [0040]    Further, a workpiece detecting sensor  25  detecting a workpiece size by rotating the rotary table  26  once is disposed above the fixed table  8   a . This workpiece detecting sensor  25  is constituted of a CCD camera, and the size of a workpiece is detected by processing an image from this camera. 
         [0041]    The workpiece replacement device  5  includes a workpiece replacement arm  17  structured to be capable of moving forward or backward in a horizontal direction, and a turning and lifting mechanism  9  turning the workpiece replacement arm  17  about a vertical axis and lifting and lowering the arm in the vertical direction. 
         [0042]    The turning and lifting mechanism  9  includes a base  9   a  which is driven to turn about the vertical axis by a turn drive motor (not shown), a pair of lifting guide support posts  10 ,  10  fixed extending in the vertical direction on an upper face of the base  9   a , a lift frame  14  supported in a liftable and lowerable manner by the pair of lifting guide support posts  10 ,  10 , a ball screw shaft  12  screwed through a nut member  15  fixed to the lift frame  14 , and a lift drive motor  13  disposed on the base  9   a  to drive the ball screw shaft  12 . Incidentally, rotation of the lift drive motor  13  is transmitted to the ball screw shaft  12  via a transmission mechanism disposed inside a transmission case  11 . 
         [0043]    The workpiece replacement arm  17  has an arm support table  19  fixed and supported on the lift frame  14 , and an arm body  17   a  supported to be movable forward and backward in the horizontal direction by the arm support table  19 . A pair of left and right guide rails  16 ,  16  are disposed on the arm support table  19 , and linear guides  16   a  provided on a bottom face of the arm body  17   a  are mounted slidably on the guide rails  16 ,  16 . Further, a forward/backward drive motor  18  which drives the arm body  17   a  is fixed on the arm support table  19 . A pinion gear  18   a  fixed on an output shaft of the forward/backward drive motor  18  meshes with a rack gear  17   b  fixed on a side face of the arm body  17   a.    
         [0044]    A bifurcated fork  17   c  supporting the pallet  23  is formed in a front end portion of the arm body  17   a . Fork pins  17   d  to be inserted in the pin holes  6   b  formed in the removable shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10  are disposed projecting upward on a base portion of the fork  17   c . Further, a switch  20  for recognizing the presence of a shelf is disposed on the base portion of the fork  17   c.    
         [0045]    In the above structure, the workpiece replacement arm  17  turns about the vertical axis when the turn drive motor (not shown) drives and turns the base  9   a , moves upward or downward when the lift drive motor  13  rotates the ball screw shaft  12 , and further moves back in the horizontal direction when the forward/backward drive motor  18  rotates the pinion gear  18   a.    
         [0046]    First, a replacement operation for a processed workpiece  4   a  and an unprocessed workpiece  4   b  mounted in a predetermined housing space of the workpiece storage unit  2  will be described. 
         [0047]    When processing the workpiece is finished, a shutter  2   b  arranged at a boundary between the processing machine  3  and the workpiece storage unit  2  opens, and the arm body  17   a  extends the fork  17   c ,  17   c  to both sides of the pallet  23  mounted on the worktable  3   b  of the processing machine  3  (see  FIGS. 4 ,  5  and  FIG. 10 ). Then the entire workpiece replacement arm  17  moves upward in the vertical direction to lift the processed workpiece  4   a  (see  FIG. 11 ), and the arm body  17   a  moves backward, thereby moving the processed workpiece  4   a  from the processing machine  3  to the workpiece storage unit  2  side. 
         [0048]    Subsequently, the turn drive motor (not shown) turns the base  9   a  about the vertical axis so that the workpiece replacement arm  17  is at the angle position corresponding to a shelf  6 A on which the processed workpiece  4   a  is to be temporarily placed, and the lift drive motor  13  rotates the ball screw shaft  12  so that the workpiece replacement arm  17  is at the height position corresponding to the shelf  6 A for temporary placement. The arm body  17   a  moves forward in the horizontal direction to the position corresponding to the shelf  6 A for temporary placement, and thereafter the entire workpiece replacement arm  17  moves down in the vertical direction, thereby transferring the processed workpiece  4   a  onto the shelf  6 A (see  FIG. 12 ). Then the arm body  17   a  moves back in the horizontal direction to its original position. 
         [0049]    Moreover, the workpiece replacement arm  17  is driven to turn about the vertical axis to be at the angle position corresponding to a shelf  6 B on which the unprocessed workpiece  4   b  is temporarily placed. The arm body  17   a  extends the fork  17   c ,  17   c  to left and right sides of the pallet (not shown) fixed to the unprocessed workpiece  4   b , and the entire workpiece replacement arm  17  moves upward in the vertical direction to lift the unprocessed workpiece  4   b , thereby removing it from the shelf  6 B (see  FIG. 13 ). The arm body  17   a  moves back in the horizontal direction to its original position. 
         [0050]    Then the workpiece replacement device  5  is driven to turn about the vertical axis to be at the angle position corresponding to the worktable  3   b  of the processing machine  3 , the arm body  17   a  moves forward in the horizontal direction so that the unprocessed workpiece  4   b  is positioned above the worktable  3   b  (see  FIG. 14 ), and the entire workpiece replacement device  5  moves downward in the vertical direction, thereby transferring the unprocessed workpiece  4   b  onto the worktable  3   b . The arm body  17   a  moves backward in the horizontal direction to its original position, the shutter  2   b  closes, and processing is started again. 
         [0051]    Next, an operation for enlarging a housing space in the workpiece storage unit  2  will be described, which is performed by moving, for example, the removable shelf  6 - 6  from the lower, front and rear support brackets  7   b ,  7   c  to an upper bracket  27 . 
         [0052]    The turn drive motor turns the base  9   a  about the vertical axis so that the workpiece replacement arm  17  is at the angle position corresponding to a relevant column of shelves, and the lift drive motor  13  rotates the ball screw shaft  12  so that the arm is at the height position corresponding to the shelf  6 - 6  for changing the housing space. Then the arm body  17   a  moves forward in the horizontal direction so that the fork  17   c  is positioned below the shelf  6 - 6 , and subsequently the entire workpiece replacement arm  17  moves upward to engage the fork pins  17   d ,  17   d  with the pin holes  6   b ,  6   b  (see  FIG. 15 ). 
         [0053]    The entire workpiece replacement arm  17  moves upward further to remove the shelf  6 - 6  from the front and rear brackets  7   b ,  7   c , and the arm body  17   a  moves back in the horizontal direction to its original position (see  FIG. 16 ). 
         [0054]    The lift drive motor  13  drives the workpiece replacement arm  17  to move upward to the height position corresponding to the upper bracket  27 , and the arm body  17   a  moves forward in the horizontal direction to the position corresponding to the upper bracket  27 . Thereafter, the entire workpiece replacement arm  17  moves down to insert the falling prevention pins  6   a  in the pin holes  7   d , and further engages the positioning projections  7   e  with the positioning holes  6   c . Thus, the shelf  6 - 6  is mounted on the upper bracket  27 , and the arm body  17   a  moves back in the horizontal direction to its original position (see  FIG. 17 ). 
         [0055]    In this embodiment, since the shelves of the workpiece storage unit  2  are constituted of the fixed shelves  6 - 1 ,  6 - 3 , . . . ,  6 - 9  and the removable shelves  6 - 2 ,  6 - 4 , . . . ,  6 - 10  and the removable shelves are moved in an upward or downward direction, the size of each housing space can be changed, and workpieces of different sizes can be housed in the same workpiece storage unit, thereby allowing to increase types of workpieces which can be housed. 
         [0056]    Further, since the workpiece replacement device  5  for replacing an unprocessed workpiece  4   b  housed in a housing space with a processed workpiece  4   a  is used for moving the shelves to change the housing space, the housing spaces can be changed without providing a new housing space changing mechanism and thus without complicating the structure of the entire machine. 
         [0057]    Further, since it is structured to enlarge the housing space by moving the removed shelf to the upper bracket  27  arranged above this shelf, it is not necessary to secure a housing space for a removed shelf separately, and it is possible to change the housing space in a short time. 
         [0058]    Since the workpiece detecting sensor  25  detecting the size of the workpiece  4  is disposed on the preparation station  8 , and the workpiece  4  is automatically housed by the workpiece replacement arm  17  in the housing space corresponding to the size of the workpiece detected by the workpiece detecting sensor  25 , it is not necessary for the operator to perform operation to specify the workpiece size with an operation board, thereby facilitating a workpiece supply operation and further preventing human errors such as errors in workpiece size. 
         [0059]    It should be noted that although the case where the housing space is enlarged by moving the shelf upward has been described in this embodiment, it is also possible to reduce a housing space by adding a shelf. In this way, the number of housing spaces can be increased. 
         [0060]    The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. 
         [0061]    The present embodiments are therefore to be considered in all respects as illustrative and no restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. 
         [0062]    The text of Japanese priority application No. 2009-136133 filed on Jun. 5, 2009, is hereby incorporated by reference.