Abstract:
A machine tool facility includes the following: machine tools; a first pallet stocker in which a plurality of pallets are arranged in parallel with a predetermined space therebetween; a second pallet stocker in which a plurality of pallets are arranged in parallel with a predetermined space therebetween, and which is disposed in parallel with the first pallet stocker; a conveyance car that conveys a pallet in a direction parallel to the row of the pallets of the first pallet stocker; a first transfer device for transferring the pallet between the first pallet stocker and the conveyance car; and a second transfer device for transferring, by horizontal movement, the pallet between the first pallet stocker and the second pallet stocker.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a U.S. National Stage patent application of International Patent Application No. PCT/JP2013/079164, filed Oct. 28, 2013, which is hereby incorporated by reference in the present disclosure in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a machine tool facility provided with one or more machine tools, a pallet stocker for storing a plurality of pallets, a conveyer apparatus for conveying pallets between the machine tools and the pallet stocker. 
       BACKGROUND OF THE INVENTION 
       [0003]    A machine tool facility, provided with a pallet stocker for storing a plurality of pallets to each of which a workpiece is mounted and a pallet changer for changing pallets between machine tools and the pallet stocker, has been known in the art. 
         [0004]    For example, PLT 1 describes a machine tool facility provided with a machine tool, which processes a workpiece mounted to a vertically oriented pallet, and a pallet stocker, disposed adjacent the machine tool, for storing a plurality of vertically oriented pallets, and a pallet changer for changing vertically oriented pallets between the machine tool and the pallet stocker. 
         [0005]    Further, PLT 2 describes a machine tool facility provided with a stocker adjacent a machine tool, a buffer provided in the stocker, a preparation station attached to the stocker, a carrier mechanism disposed above the stocker for moving reciprocally in the longitudinal direction of the stocker, a lifter mechanism disposed on the carrier mechanism, provided for moving reciprocally in the vertical direction, for holding a pallet, and an operation controller for controlling the carrier mechanism based on the addresses corresponding to the positions of the pallets. 
         [0006]    Furthermore, PLT 3 describes a machine tool facility including one or more machine tools, multistage stacking pallet stockers, and a conveyer means for conveying a workpiece. 
       CITATIONS LIST 
       [0007]    PLT 1: Japanese Patent No. 4799423 B2 
         [0008]    PLT 2: Japanese Patent No. 2974803 B2 
         [0009]    PLT 3: Japanese Patent Publication No. S61-297066 A 
       SUMMARY OF THE INVENTION 
       [0010]    The pallet stocker of the machine tool facility of PLT 1 includes a plurality of vertically oriented pallet mounting faces perpendicular to the rails of the pallet changer. Accordingly, in order to store more pallets, it is necessary to extend the pallet stocker in the direction of the rails of the pallet changer so as to increase the number of the pallet mounting faces. Therefore, according to the configuration of the machine tool facility of PLT 1, a pallet stocker can store limited number of pallets within an area assigned to a machine tool facility. 
         [0011]    The pallet stocker of the machine tool facility of PLT 2 stores pallets arranged in two rows wherein the pallets must be lifted by the lifter mechanism in order to move them from one row to the other within the pallet stocker. Therefore, the pallet stocker of PLT 2 must be complex and increased in size, and further it is very difficult to store a large pallet for mounting a large workpiece. 
         [0012]    The pallet stocker of the machine tool facility of PLT 3 stores pallets in the form of matrix within a vertical plane. Therefore, according to the machine tool facility of PLT 3, a complex mechanism is necessary to move the pallets in the pallet stocker. Furthermore, it is very difficult for the pallet stocker of PLT 3 to store a large pallet for mounting a large workpiece. 
         [0013]    The invention is directed to solve the above-described problems of the prior art, and the objective of the invention is to provide a machine tool facility which can store a large number of pallets effectively within a narrow space without increasing the size of a pallet transferring device. 
         [0014]    In order to solve the above-described problem, the invention provides a machine tool facility adapted to convey and transfer pallets between a machine tool and a pallet stocker, characterized by a first pallet stocker adapted to store an array of a plurality of pallets disposed at an interval, a second pallet stocker, arranged parallel to the first pallet stocker, and adapted to store an array of a plurality of pallets disposed at an interval, a carriage for conveying a pallet in the direction parallel to the array of the pallets, a first transferring device for transferring a pallet between the first pallet stocker and the carriage, and a second transferring device for transferring a pallet horizontally between the first pallet stocker and the second pallet stocker. 
         [0015]    According to the invention, the configuration of the length of the pallet stockers can be reduced by arranging the second pallet stocker arranged parallel to the first pallet stocker and disposing the second transferring device between the first and second pallet stockers. The machine tool facility can store as many pallets as possible within a narrow free space which does not allow a long pallet stocker to be installed in a factory. 
         [0016]    The second transferring device, adapted to transfer pallets between the first pallet stocker and the second pallet stocker, does not necessary to hold a pallet, and therefore a small device can be used even when large pallets are stored. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]      FIG. 1  is a plan view of a machine tool facility according to a preferred embodiment of the invention. 
           [0018]      FIG. 2  is a plan view of a machine tool of the machine tool facility of  FIG. 1 . 
           [0019]      FIG. 3  is a side view of a carriage and a first transferring device of the machine tool facility of  FIG. 1 . 
           [0020]      FIG. 4  is a side view of a second transferring device of the machine tool facility of  FIG. 1 . 
           [0021]      FIG. 5A  is a side view of first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining a process for transferring a pallet from the first pallet stocker to the carriage. 
           [0022]      FIG. 5B  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the first pallet stocker to the carriage. 
           [0023]      FIG. 5C  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the first pallet stocker to the carriage. 
           [0024]      FIG. 5D  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the first pallet stocker to the carriage. 
           [0025]      FIG. 5E  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the first pallet stocker to the carriage. 
           [0026]      FIG. 5F  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the first pallet stocker to the carriage. 
           [0027]      FIG. 6A  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining a process for transferring a pallet from the second pallet stocker to the first pallet stocker. 
           [0028]      FIG. 6B  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the second pallet stocker to the first pallet stocker. 
           [0029]      FIG. 6C  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the second pallet stocker to the first pallet stocker. 
           [0030]      FIG. 6D  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the second pallet stocker to the first pallet stocker. 
           [0031]      FIG. 6E  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the second pallet stocker to the first pallet stocker. 
           [0032]      FIG. 6F  is a side view of the first and second pallet stockers and the carriage of the machine tool facility of  FIG. 1 , explaining the process for transferring a pallet from the second pallet stocker to the first pallet stocker. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    With reference to the drawings, a preferred embodiment of the invention will be described below. 
         [0034]    In  FIG. 1 , a machine tool facility  10  according to the present embodiment comprises a least one, in this embodiment two machine tools  100 A and  100 B, first and second pallet stockers  200 A and  300 B, disposed adjacent one of the machine tools  100 A and  100 B, a carriage  200  disposed between the machine tools  100 A and  100 B and the first and second pallet stockers  300 A and  300 B. 
         [0035]    In this embodiment, the machine tools  100 A and  100 B have the same configuration, and therefore with reference to  FIG. 2 , only the machine tool  100 A will be described below. 
         [0036]    The machine tool  100 A comprises a bed  102 , providing a base, a column  104  mounted to the bed  102  for horizontally moving in X-axis direction (the up-and-down direction in  FIGS. 1 and 2 ), a Y-axis slider  106  mounted to the front face of the column  104  for vertically moving in Y-axis direction (perpendicular to the plane of  FIGS. 1 and 2 ), a spindle head  108  mounted to the Y-axis slider  106  for moving in Z-axis direction (left-and-right direction in  FIGS. 1 and 2 ) perpendicularly intersecting the X-axis, a spindle  110  supported by the spindle head  108  for rotation about an axis O parallel to the Z-axis, and a table  112  or a pallet mount  112 , disposed so as to face the spindle  110  in the Z-axis direction and having a pallet mounting face to which a pallet P is secured. 
         [0037]    With reference to  FIG. 3 , the carriage  200  will be described below. 
         [0038]    The carriage  200  comprises a base  202 , vertically oriented first and second pallet supports  204  and  206  mounted to the base  202 , and a transferring device  210  for transferring a pallet P between the first pallet stocker  300 A and the first and second pallet supports  204  and  206 . Mounted to the bottom face of the base  202  are a plurality of rollers  202   a  which roll along a pair of rails  220  extending in the Z-axis direction. A drive pinion  226  and a drive motor  224 , for rotationally driving the drive pinion  226 , are mounted to the base  202 . The drive motor  224  has a vertically oriented output shaft  224   a  downwardly extending from the bottom face of the base  202 . The drive pinion  226  is mounted to the output shaft  224   a.  The drive pinion  226  engages with teeth of a rack  222  extending in the Z-axis direction between the pair of rails  220 . 
         [0039]    The first and second pallet supports  204  and  206  are secured to the top face of the base  202  so that they are oriented perpendicularly to the Z-axis of the machine tools  100 A and  100 B. Accordingly, the workpiece mounting face of a pallet P mounted to each of the pallet mounting faces of the pallet supports  204  and  206  extends vertical. Further, the first and second pallet supports  204  and  206  are provided with a plurality of rollers  208  for engaging the bottom edges of the pallets P mounted to the pallet mounting faces so as to support the pallets P. 
         [0040]    Each of the first and second pallet supports  204  and  206  is provided with a transferring device  210 . Although  FIG. 3  shows only the transferring device  210  mounted to the first pallet support  204 , the second pallet support  206  also has a transferring device (not shown) having the configuration the same as the transferring device  210 . 
         [0041]    The transferring device  210  has a moving bracket  212  mounted to the first pallet support  204  for moving in the X-axis direction of the machine tools  100 A and  100 B. The pallet mounting face of each of the pallet supports  204  and  206  is provided with guide rails  214  extending in the X-axis direction of the machine tools  100 A and  100 B. The moving bracket  212  has shoes (not shown) engaging the guide rails  214 . A piston rod of a first actuator  218   a , such as a pneumatic cylinder or a hydraulic cylinder, is connected to one of the end of the moving bracket  212 . Accordingly, the first actuator moves reciprocally the moving bracket  212  along the guide rails  213  in a horizontal direction, i.e., in the X-axis direction of the machine tools  100 A and  100 B, between an extended position and a retracted position, as shown by an arrow H. 
         [0042]    The moving bracket  212  is provided with a pinion  216 . The pinion  216  is mounted to an output shaft  216   a  of a motor (not shown) for rotationally driving the pinion  216 . The motor is mounted to the moving bracket  212  for moving vertically, i.e., in the Y-axis direction of the machine tools  100 A and  100 B, as shown by an arrow V, between an upper position and a lower position. A second actuator  218   b,  such as a pneumatic cylinder or a hydraulic cylinder, for vertically moving the motor and the pinion  216 , is mounted to the moving bracket  212 . 
         [0043]    With reference to  FIG. 1 , the first and second pallet stockers  300 A and  300 B have the same configuration. Further, the first and second pallet stockers  300 A and  300 B comprise pallet holders  302 A and  302 B. The pallet holders  302 A and  302 B of the first and second pallet stockers  300 A and  300 B are aligned with each other in the X-axis direction of the machine tools  100 A and  100 B or are disposed in an X-Y plane parallel to the X-Y plane of the first and second machine tools  100 A and  100 B. Thus, each of the first and second pallet stockers  300 A and  300 B is configured to store an array of a plurality of pallets P, which are oriented parallel to X-Y plane of the first and second machine tools  100 A and  100 B and arranged in a row in the Z-axis direction of the first and second machine tools  100 A and  100 B. 
         [0044]    Disposed between the first and second pallet stockers  300 A and  300 B is a second transferring device  400  for transferring a pallet P between the first and second pallet stockers  300 A and  300 B. With reference to  FIG. 4 , the second transferring device  400  has a base  402  and a moving bracket  404  mounted to the base  402  for moving reciprocally in the X-axis direction of the first and second machine tools  100 A and  100 B. 
         [0045]    A plurality of rollers  402   b  is mounted to the bottom face of the base  402  for rolling along a pair of rails  420  extending in the Z-axis direction. A drive pinion  426  and a drive motor  424 , for rotationally driving the drive pinion  426 , are mounted to the base  402 . The drive motor  424  has a vertically oriented output shaft  424   a  downwardly extending from the bottom face of the base  402 . The drive pinion  426  is mounted to the output shaft  424   a.  The drive pinion  426  engages with teeth of a rack  422  extending in the Z-axis direction between the pair of rails  420 . Thus, the second transferring device can reciprocally move, between the first and second pallet stockers  300 A and  300 B, in the direction parallel to the row of the pallets P, stored in the first and second pallet stockers  300 A and  300 B. 
         [0046]    A guide rail  402   a  is mounted to the top face of the base  402  so as to extend in the X-axis of the machine tools  100 A and  100 B. The moving bracket  404  has shoes  404   a  engaging the guide rails  402   a.  A piston  414   a  a first actuator  414 , such as a pneumatic cylinder or a hydraulic cylinder, is connected to a bottom part of the moving bracket  404 . Accordingly, the first actuator  414  moves reciprocally the moving bracket  404  along the guide rails  402   a  in a horizontal direction, i.e., in the X-axis direction of the machine tools  100 A and  100 B, between first and second positions, as shown by an arrow H. 
         [0047]    The moving bracket  404  is provided with first and second pinions  406  and  410 . The first and second pinions  406  and  410  are mounted to output shafts  406   a  and  410   a  of motors (not shown) for rotationally driving the first and second pinions  406  and  410 . The motors are mounted to the moving bracket  404  for moving vertically, i.e., in the Y-axis direction of the machine tools  100 A and  100 B, as shown by an arrow V, between an upper position and a lower position. Second and third actuators  408  and  412 , such as a pneumatic cylinder or a hydraulic cylinder, for vertically moving the motors and the first and second pinions  406  and  410 , are mounted to the moving bracket  404 . 
         [0048]    With reference to  FIGS. 5A-5F  and  FIGS. 6A-6F , the operation of the present embodiment will be described and with reference to  FIGS. 5A-5F , the operation for transferring a pallet P from the first pallet stocker  300 A to the carriage  200  will be described below. 
         [0049]    The carriage  200  runs along the rails  220 , according to a command from a controlling system for the machine tool facility  10 , so as to align one of the pallet supports  204  and  205 , at the first pallet stocker  300 A, with one of the pallet holders  302 A holding a pallet P to be mounted to the carriage  200 . At that time, a pallet P is not mounted to the pallet support  204  or  206  which should receive a pallet P from the first pallet stocker  300 A. 
         [0050]    When the pallet support  204  or  206  is aligned with one of the pallet holders  302 A ( FIG. 5A ), the transferring device  210  is activated whereby the first actuator  218   a  is extended. This results in moving the bracket  212  horizontally to the extended position ( FIG. 5B ). At the extended position, the pinion  216  is positioned under the rack R of the pallet P which is held by the first pallet stocker  300 A. Then, the second actuator  218   b  is extended. This moves the pinion  216  vertically upwardly toward the upper position. At the upper position, the pinion  216  engages the teeth of the rack R ( FIG. 5C ). 
         [0051]    When pinion  216  engages the rack R, the pinion  216  is rotationally driven so that the pallet P is drawn from the support rollers  310  of the first pallet stocker  300 A and transferred to the support rollers  208  of the carriage  200  ( FIG. 5D ). When the pallet P is drawn to a position where the pinion  216  engages the end of the rack R, as shown  FIG. 5E , the first actuator  218   a  is retracted so that the moving bracket  212  is moved horizontally toward the retracted position ( FIG. 5F ). Accordingly, the transferring device  210  moves pallet P from the first pallet stocker completely to the carriage  200  by the engagement between the pinion  216  and rack R. 
         [0052]    When a pallet P is moved from the carriage  200  to the first pallet stocker  300 A, one of the pallet support  204  and  206 , supporting the pallet P, of the carriage  200  is aligned with one of the pallet holders  302 A, which should receive the pallet P, thereafter the above described process is carried out in the reverse order. 
         [0053]    Further, when a pallet P is transferred from the first machine tool  100 A or the second machine tool  100 B to the carriage  200 , the process shown in  FIGS. 5A-5F  is similarly carried out. Furthermore, it should be understood that when a pallet P is moved from the carriage  200  to the first machine tool  100 A or the second machine tool  100 B the process shown in  FIGS. 5A-5F  is inversely carried out. 
         [0054]    With reference to  FIGS. 6A-6F , the process for transferring a pallet P from the second pallet stocker  300 B to the first pallet stocker  300 A will be described below. 
         [0055]    The controlling system for the machine tool facility  10  confirms that there is no pallet P held by the pallet holder  302 A of the first pallet stocker  300 A corresponding to the pallet holder  302 B, holding the pallet P to be transferred, of the second pallet stocker  300 B. Then, the second transferring device  400  is aligned with the pallet holder  302 B, holding the pallet P to be transferred, and the pallet holder  302 A which should receive the pallet P ( FIG. 6A ). Accordingly, the second transferring device  400  is placed between the first and second pallet stocker  300 A and  300 B at a position, allowing the first and second pinions  406  and  410  to engage the rack R, provided on the back side of the pallet P, held by the pallet stocker  302 B. 
         [0056]    Then, the first actuator  414  of the second transferring device  400  is activated whereby the moving bracket  404  is moved horizontally toward the second position ( FIG. 6B ). At the second position, the second pinion  410  is positioned under the rack R of the pallet P held by the second pallet stocker  300 B. Then, the third actuator  412  is extended. This results in the second pinion  410  moved vertically upwardly toward the upper position. At the upper position, the second pinion  410  engages the teeth of the rack R ( FIG. 6C ). 
         [0057]    When the second pinion  410  engages the rack R, the second pinion  410  is rotationally driven whereby the pallet P is moved from the second pallet stocker  300 B toward the first pallet stocker  300 A. At the same time, the second actuator  408  is extended. This results in moving the first pinion  406  vertically upwardly toward the upper position. In this state, when the second pinion  410  is rotated, the rack R engages both the first and second pinions  406  and  410 . Then, the pallet P is drawn further by both the first and second pinions  406  and  410  ( FIG. 6D ). This results in the pallet P being moved onto the support rollers  310  of the first pallet stocker  300 A from the support rollers  312  of the second pallet stocker  300 B. 
         [0058]    As shown in  FIG. 6E , when the pallet P is moved to a position where the second pinion  410  engages the end of the rack R, the first actuator  414  is extended in the opposite direction whereby the moving bracket  404  is moved horizontally toward the first position ( FIG. 6F ). Then, the first pinion  406  is further rotated whereby the pallet P is transferred to the first pallet stocker  300 A. Accordingly, the transferring device  400  moves the pallet P to the first pallet stocker  300 A completely from the second pallet stocker  300 B by the engagement between the first and second pinions  406  and  410  and the rack R. 
         [0059]    It should be understood that a pallet P can be transferred from the first pallet stocker  300 A to the second pallet stocker  300 B by carrying out the above described process in the reverse order. 
         [0060]    Although in the above described embodiment, rack and pinion(s) are used, a combination of chain and sprockets may be used. 
         [0061]    The present invention enables more pallets to be stored in a narrow space. In particular, when the machine tools and the pallet stockers are arranged parallel and next to each other, the advantageous merit of the invention is maximized, as shown in the above described embodiment. In case of a single row type pallet stocker, a dead space will be defined due to the difference in widths of the pallet stocker and the machine tool. The machine tool is provided with a feed axis having a stroke substantially the same as the length of a pallet. Therefore, the width of the machine tool is twice of the length of the pallet stocker. Accordingly, the pallet stocker, having first and second rows, arranged parallel and next to the machine tool(s), allows the machine tool facility to be installed in a rectangular space, minimizing the dead space. 
       REFERENCE SIGNS LIST 
       [0062]      100 A Machine Tool 
         [0063]      100 B Machine Tool 
         [0064]      200  Carriage 
         [0065]      204  First Pallet Support 
         [0066]      206  Second Pallet Support 
         [0067]      208  Support Roller 
         [0068]      210  Transferring Device 
         [0069]      212  Moving Bracket 
         [0070]      216  Pinion 
         [0071]      218   a  First Actuator 
         [0072]      218   b  Second Actuator 
         [0073]      300 A First Pallet Stocker 
         [0074]      300 B Second Pallet Stocker 
         [0075]      302 A Pallet Holder 
         [0076]      302 B Pallet Holder 
         [0077]      310  Support Roller 
         [0078]      312  Support Roller 
         [0079]      400  Second Transferring Device 
         [0080]      404  Moving Bracket 
         [0081]      406  First Pinion 
         [0082]      410  Second Pinion