Patent Document

CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. §119(a) to European Application No. 12 178 805.3, filed on Aug. 1, 2012, the entire contents of which are hereby incorporated by reference. 
       TECHNICAL FIELD 
       [0002]    The invention relates to a machine tool for processing plate-like workpieces, in particular metal sheets. 
       BACKGROUND 
       [0003]    A representative machine tool for processing plate-like workpieces, in particular metal sheets, is known from EP 0 648 556 A1. This document discloses a turret punch press for sheet metal processing with an O-shaped machine frame. A coordinate guide for the metal sheets to be processed and a tool turret are housed in the inner compartment of the frame. The tool turret is rotatable about a vertical axis and is provided along the circumference thereof with a plurality of storage places for punching tools. A feed motion of the tool turret about the axis of rotation causes the particular punching tool that is required for the workpiece processing to be carried out to be positioned at a processing station of the turret punch press. A tool transfer device loads the storage places of the tool turret with the punching tools required for the forthcoming workpiece processing. Punching tools no longer required are removed by the tool transfer device from the storage places of the tool turret, punching tools that are required are transferred by the tool transfer device to the storage places of the tool turret. In so doing, in addition to approaching the tool turret the tool transfer device approaches a tool magazine spaced from the tool turret; the tool transfer device removes from said tool magazine the punching tools to be supplied to the tool turret and the tool transfer device inserts into said tool magazine the punch tools removed from the tool turret. The storage places of the tool magazine provided for the punching tools are housed in a frame compartment open towards one longitudinal side of the machine frame. The tool transfer device moves in the longitudinal direction of the machine frame between a position in which it is arranged in front of the lateral opening of the frame compartment and a position in which is it located adjacent a punching tool storage place provided on the tool turret. For receiving or transferring a punching tool, the tool transfer device engages in the horizontal direction in the relevant storage place on the tool turret or in the relevant storage place on the tool magazine. During movement along the machine frame the tool transfer device is guided on guide rails running horizontally and offset with respect to each other perpendicularly to a longitudinal lateral wall of the machine frame. 
         [0004]    Other improvements in machine tools for processing plate-like workpieces, in particular metal sheets, are sought. 
       SUMMARY 
       [0005]    One aspect of the invention features a machine tool for processing plate-like workpieces, in particular metal sheets. The machine tool includes a machine frame having lower and upper frame arms extending in a longitudinal direction of the machine frame and spaced apart in a vertical direction to define a frame compartment. A processing station is supported by the machine frame and configured to interchangeably receive a processing tool for workpiece processing. The machine tool has a first tool magazine disposed at least partially within the frame compartment and defining storage places configured to store processing tools interchangeable at the processing station. The first tool magazine and the processing station are movable relative to each other so as replace a processing tool at the processing station with a processing tool from the first tool magazine. A second tool magazine defines storage places configured to store processing tools remote from the processing station, and is disposed farther than the first tool magazine from the processing station. A tool transfer device has a tool holder configured to hold processing tools during tool transfer between the first and second tool magazines, the tool transfer involving relative motion between the tool holder and at least one of the first and second tool magazines in the longitudinal direction of the machine frame. 
         [0006]    According to this aspect of the invention the remote or second tool magazine includes a magazine platform that protrudes laterally in a horizontal direction with respect to the machine frame and is accessible from above with storage places for processing tools to be interchanged at the processing station. The tool transfer device is mounted above the magazine platform on the relevant longitudinal side of the machine frame. The magazine platform is accordingly provided on the outside of the machine frame and is readily accessible there for the tool transfer device tool holder arranged above the magazine platform. The arrangement of the magazine platform and the tool transfer device on the outside of the machine frame in particular provides an opportunity for existing machine tools that do not have a remote tool magazine to be retrofitted with such a tool magazine at no great expense. 
         [0007]    The remote tool magazine, including the magazine platform, can in principle be designed as a unit separate from the machine frame of the machine tool, but a magazine platform connected to the machine frame is preferred. By virtue of said connection the magazine platform is arranged in a permanently defined manner with respect to the remaining functional units of the machine tool, more especially also with respect to the tool transfer device. This circumstance facilitates in particular a positionally accurate relative movement of the magazine platform and the tool transfer device. 
         [0008]    There are different options for configuring the tool magazine that is close to the station. In a preferred construction, the tool magazine close to the station comprises a horizontal carrier arranged at least partially in the frame inner compartment of the machine frame and extending transversely to the longitudinal direction of the machine frame. Storage places for processing tools are provided adjacent each other in the longitudinal direction of the carrier. The storage places of such a linear magazine are easily accessible for the tool transfer device. So that all storage places arranged along the horizontal carrier can be reached by the tool transfer device, the horizontal carrier and the tool transfer device are movable relative to each other in the longitudinal direction of the horizontal carrier. For that purpose the horizontal carrier of the linear magazine is preferably movably guided in the longitudinal direction thereof on the machine frame. 
         [0009]    In order to transfer processing tools between the remote tool magazine and the tool magazine close to the station, a tool transfer movement is carried out in the longitudinal direction of the machine frame. This tool transfer movement is a relative movement between the tool holder of the tool transfer device on the one hand, and the remote tool magazine and/or the tool magazine close to the station on the other hand. 
         [0010]    In order to carry out the tool transfer movement, the tool holder of the tool transfer device may be moved on the machine frame in the longitudinal direction of the frame into a receiving/transfer position remote from the station at the tool magazine remote from the station, and into a receiving/transfer position close to the station at the tool magazine close to the station. Advantageously, the tool holder of the tool transfer device constitutes only a small mass to be moved. This circumstance is accompanied in particular by high positional accuracy when approaching the receiving/transfer positions at the remote tool magazine and at the tool magazine close to the station. In addition, the tool transfer movement can be achieved by means of comparatively low-power and hence inexpensive drives. 
         [0011]    In addition or as an alternative, in a further embodiment the tool magazine close to the station and/or the magazine platform of the remote tool magazine are/is movable with a tool transfer movement along the machine frame. In particular the tool holder of the tool transfer device can be fixedly connected to the machine frame. The tool magazine close to the station and/or the magazine platform of the remote tool magazine takes on at least part of the tool transfer movement. This option for producing the tool transfer movement is appropriate in particular in cases in which the tool magazine close to the station is movable in any case in the longitudinal direction of the machine frame. This is the case, for example, when the tool magazine close to the station is integrated in a coordinate guide for the workpieces to be machined. If the tool magazine close to the station, which tool magazine is already provided with a drive, takes on the complete tool transfer movement between the remote tool magazine and the tool magazine close to the station, then no separate drive is needed for the tool transfer. 
         [0012]    In some embodiments the magazine platform of the remote tool magazine actively performs a tool transfer movement that is advantageously generated by means of the movable tool magazine close to the station. 
         [0013]    If, for the tool transfer movement, the magazine platform of the remote tool magazine can be detachably coupled to the tool magazine which is close to the station and is in any case driven, then the connection of the magazine platform to the tool magazine close to the station can be limited to those cases in which a tool transfer movement has to be performed. In the case of other movements, the magazine platform does not need to be moved by the tool magazine close to the station. 
         [0014]    In a further preferred embodiment, the magazine platform of the remote tool magazine, which magazine platform is disengaged from the tool magazine close to the station, is arranged in a rest position away from the receiving/transfer position. In this manner it is ensured that the remote tool magazine not currently in use does not impede the other procedures of the machine tool. 
         [0015]    In the interests of an efficient tool management, in some embodiments the tool holder of the tool transfer device comprises a plurality of tool holding elements that are offset with respect to each other in the direction of the tool transfer movement. By virtue of this feature it is possible in particular to carry out a tool removal operation and a tool transfer operation in immediate succession. If the receiving position of the one tool holding element coincides with the transfer position of the other tool holding element, then only a comparatively short transfer path has to be covered between the take up of the one tool and the transfer of the other tool. In addition, the mutual offset of the tool holding elements in the direction of the tool transfer movement and hence in the longitudinal direction of the machine frame keeps the projection of the tool holder in the transverse direction of the machine frame to a minimum. 
         [0016]    In some embodiments, the tool holder is adjustable in a horizontal direction perpendicular to the longitudinal direction of the machine frame with respect to the magazine platform of the second tool magazine, and advantageously has a large range. The magazine platform of the remote tool magazine can be designed correspondingly for receiving processing tools. 
         [0017]    In a further preferred embodiment the magazine platform of the remote tool magazine is supported interchangeably on a supporting structure of the remote tool magazine. As a result of this feature, the configuration of the remote tool magazine can be adapted in a simple manner to changing requirements. For example, after completion of a processing task a magazine platform fitted with the relevant set of processing tools can be replaced by a magazine platform on which the processing tools required for the succeeding processing are arranged. The magazine platforms can be set up away from the machine tool. Exchange of the magazine platforms can be effected manually, for example. 
         [0018]    Another aspect of the invention features a method of changing processing tools in a machine for processing plate-like workpieces, in particular metal sheets, such as in an automated punching machine. The method includes, in reference to a machine of the type described herein: activating a tool transfer device positioned above a selected processing tool stored in a processing tool storage place of the second tool magazine, such that the tool transfer device holds a processing tool stored in the second tool magazine; initiating a relative motion between the tool transfer device and the first tool magazine in the longitudinal direction of the machine frame, thereby moving the held processing tool to the first tool magazine; releasing the held processing tool and storing the released processing tool in a storage place of the first tool magazine; reducing a distance between the first tool magazine and the processing station; and replacing a processing tool held in the processing station with the stored processing tool. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0019]      FIGS. 1 through 9  sequentially illustrate the replacement of a processing tool in a punching machine for sheet metal processing, with a tool transfer device and a first construction of a remote tool magazine. 
           [0020]      FIGS. 10 and 11  show a tool changeover process in a second embodiment of a punching machine for sheet metal processing. 
       
    
    
       [0021]    Like reference numbers in the figures indicate like elements. 
       DETAILED DESCRIPTION 
       [0022]    Referring first to  FIG. 1 , a machine tool designed as a punching machine  1  for processing metal sheets  2  has a C-shaped machine frame  3  with a lower frame arm  4  and an upper frame arm  5 . The lower frame arm  4  and the upper frame arm  5  extend in the longitudinal direction of the machine frame  3  and are spaced apart from each other in the vertical direction to form a frame inner compartment or throat  6 . At the free end of the lower frame arm  4  and the upper frame arm  5  there is a punching station  7 , hidden in the figures, of conventional construction as the processing station of the punching machine  1 . The punching station  7  comprises in the usual manner a lower tool seat on the lower frame arm  4  and an upper tool seat on the upper frame arm  5 . 
         [0023]    A likewise customary coordinate guide  8  is partially accommodated in the throat  6  of the machine frame  3 . The coordinate guide  8  comprises a cross beam  9 , which is movably guided on the lower frame arm  4  in the longitudinal direction of the machine frame  3  and can be moved by motor in the direction of double arrow  10 . The cross beam  9  in turn guides a horizontally running cross rail  11 , which is arranged partially inside the throat  6  and which is moved by means of a motor drive in the direction of a double arrow  12  transversely to the machine frame  3 . The cross rail  11  is provided with clamping claws  13  and also has storage places  14  for processing tools in the form of punching tools  15 . The punching tools  15  are of conventional construction and accordingly include a punch as the upper tool, a die as the lower tool, and a stripper. The individual parts of each of the punching tools  15  are housed, as is customary, in a tool cassette. The relevant tool cassette is manipulated to manage the punching tools  15 . The punching tools  15 , including the respective associated tool cassettes, are illustrated merely schematically in the figures. 
         [0024]    By means of the clamping claws  13  a metal sheet  2  to be processed is fixed in the customary manner to the coordinate guide  8 . Owing to the fact that the cross beam  9  is movable in the direction of double arrow  10  and the cross rail  11  is movable in the direction of double arrow  12 , the metal sheet  2  can be moved by the coordinate guide  8  in a horizontal processing plane defined by double arrows  10  and  12 . Corresponding movements of the metal sheet  2  are performed in order to position the metal sheet  2  with respect to the punching station  7  of the punching machine  1  for the processing operation and in order to move the metal sheet  2  relative to the punching station  7  during the punching operation. In both cases the metal sheet  2  is supported on a stationary workpiece table  16  of the punching machine  1 . 
         [0025]    With the storage places  14  for punching tools  15 , the cross rail  11  of the coordinate guide  8  forms a tool carrier or a tool magazine that is arranged close to the processing station  7 . Usually, the cross rail  11  is fitted with a punching tool set comprising a plurality of punching tools  15  for the particular sheet metal processing to be carried out. For the sake of clarity, only a maximum of two punching tools  15  are shown on the cross rail  11  in the figures. 
         [0026]    The punching tools  15  are interchanged at the upper tool seat and at the lower tool seat of the punching station  7  in the customary manner by means of the coordinate guide  8 . The mobility of the cross beam  9  of the coordinate guide  8  in the direction of double arrow  10  and the mobility of the cross rail  11  in the direction of double arrow  12  is also used for that purpose. For tool changeover, the coordinate guide  8  first approaches the punching station  7  with an empty storage space  14  on the cross rail  11 . The punching tool  15  inserted at the punching station  7  is subsequently transferred out of the upper tool seat and out of the lower tool seat of the punching station  7  to the previously empty storage place  14  of the cross rail  11 . The punching tool  15  required for the next processing step and which is held ready on the cross rail  11  is subsequently inserted into the upper tool seat and into the lower tool seat of the punching station  7  by corresponding movement of the coordinate guide  8 . 
         [0027]    During tool changeover at the punching station  7  the metal sheet  2  to be processed is released from the coordinate guide  8  and rests on the workpiece table  16 . Once the tool changeover at the punching station  7  is completed, the metal sheet  2  to be processed is gripped by the coordinate guide using the clamping claws  13  and then to carry out the impending processing is moved relative to the punching tool  15  inserted at the punching station  7 . 
         [0028]    The punching tools  15  stored at the storage places  14  of the cross rail  11  come from a tool magazine  17  remote from the station, which tool magazine is provided close to the throat  6  at the rear end of the machine frame  3 . The remote tool magazine  17  has a magazine platform  18 , which is pushed interchangeably into a supporting structure  19  of the remote tool magazine  17 , the supporting structure being secured to the machine frame  3 . The magazine platform  18  is thus detachably connected to the machine frame  3 . The magazine platform  18  has on the top face thereof storage places  20  for punching tools  15 . In the example illustrated, four storage place rows running parallel to one another in the longitudinal direction of the machine frame  3 , each row having six storage places  20 , are provided on the magazine platform  18 . The magazine platform  18  can accordingly store a total of twenty-four punching tools  15 . If the machine frame  3  has a suitable length, a storage place row can have, for example, seven storage spaces  20 . Handles  21 ,  22  on the magazine platform  18  are used for handling the magazine platform  18  during exchange thereof. 
         [0029]    In order to transfer punching tools  15  between the remote tool magazine  17  and the tool magazine close to the station (i.e., the cross rail  11  of the coordinate guide  8 ), a tool transfer device  23  is used. Operation of the tool transfer device  23  is illustrated in  FIGS. 1 to 9 . The tool transfer device comprises a tool holder  24  with two tool holding fixtures in the form of tool grippers  25 ,  26 . The tool grippers  25 ,  26  are of conventional construction. They can be opened and closed by motor and are numerically controlled. 
         [0030]    The tool holder  24  with both tool grippers  25 ,  26  is movably guided on a transfer carriage  27  of the tool transfer device  23  in the transverse direction of the machine frame  3 . In addition, the tool grippers  25 ,  26  and the tool holder  24  can be raised and lowered vertically with respect to the transfer carriage  27 . In its turn the transfer carriage  27  is movable along the upper frame arm  5  of the machine frame  3  on guide rails  28 ,  29  fixed to the machine frame. All movements of the tool holder  24  and of the transfer carriage  27  of the tool transfer device  23  are generated by means of drive motors, not shown in detail. A programmable numeric control  30  indicated in outline in  FIG. 1  controls the drive motors of the tool transfer device  23  and also all other essential functions of the punching machine  1 . 
         [0031]    If an empty storage place  14  on the cross rail  11  is to be fitted with a specific punching tool  15  stored in the tool magazine  17  remote from the station, then the coordinate guide  8  first moves into its rear end position on the machine frame  3 . Subsequently or simultaneously the tool holder  24  is moved with one of the tool grippers  25 ,  26 , in the example illustrated with tool gripper  25 , along the upper frame arm  5  of the machine frame  3  into a receiving position above the punching tool  15  that is to be interchanged on the cross rail  11 ; at this point the punching tool  15  is still stored on the magazine platform  18  of the remote tool magazine  17 . For this purpose the transfer carriage  27  of the tool transfer device  23  moves along the guide rails  28 ,  29 . 
         [0032]    From the position above the punching tool  15  to be transferred, the opened tool gripper  25  is lowered towards the magazine platform  18  of the remote tool magazine  17  until it is located at the punching tool  15  to be picked up. By appropriate operation of the tool gripper  25  the punching tool  15  is fixed to the tool gripper  25 . The situation is then as shown in  FIG. 1 . With the tool holder  24  still located in the receiving position at the remote tool magazine  17 , the tool gripper  25  with the punching tool  15  fixed thereto is raised and the punching tool  15  is consequently removed from its storage place  20  on the magazine platform  18  of the remote tool magazine  17  ( FIG. 2 ). 
         [0033]    The tool holder  24  is subsequently moved, jointly with the punching tool  15  held thereon, by the transfer carriage  27  with a tool transfer movement along the machine frame  3  in the direction towards the cross rail  11  until the tool holder  24  has reached its transfer position, close to the station, at the cross rail  11  ( FIG. 3 ). Once the tool holder  24  assumes its transfer position close to the station, then the punching tool  15  on the tool gripper  25  is positioned above the particular storage place  14  of the cross rail  11  to which it is to be transferred. The cross rail  11  is correspondingly positioned relative to the cross beam  9  of the coordinate guide  8  in the direction of double arrow  12 . 
         [0034]    For transfer of the punching tool  15  to the cross rail  11 , the tool gripper  25  of the tool holder  24  is lowered vertically and the punching tool  15  is thereby inserted into the relevant storage place  14  on the cross rail  11  ( FIG. 4 ). The punching tool  15  is subsequently released from the tool holder  24  by opening the tool gripper  25 . After transfer of the punching tool  15  to the cross rail  11 , the tool gripper  25  of the tool holder  23  is raised ( FIG. 5 ). 
         [0035]    If a further punching tool  15  is to be transferred from the remote tool magazine  17  to the cross rail  11 , then the transfer carriage  27  of the tool transfer device  23  moves with the tool holder  24  in the direction towards the rear end of the machine frame  3  until the tool holder  24  is located with the tool gripper  25  or with the tool gripper  26  in the receiving position remote from the station above the relevant punching tool  15  on the magazine platform  18  of the remote tool magazine  17 . Depending on the position of the storage place  20  of the punching tool  15  in question, it may be necessary to move the tool gripper  25 ,  26  that is used for the tool transfer perpendicularly to the machine frame  3 , in order to be able to access a punching tool  15  of the middle row of storage places  20  or one of the rows of storage places furthest from the machine frame on the magazine platform  18  of the remote tool magazine  17 . 
         [0036]    In the manner described above, the punching tool  15  to be transferred is picked up from the magazine platform  18  of the remote tool magazine  17  and inserted at the cross rail  11 . 
         [0037]    During the movement along the machine frame  3 , the tool holder  24  with the two tool grippers  25 ,  26  is always located on the transfer carriage  27  in the end position close to the frame perpendicular to the machine frame  3 . Mass-related forces that would arise if the tool holder  24  was spaced further away from the machine frame  3  during its movement along the machine frame  3  are in this manner avoided. 
         [0038]    The sequence of a tool transfer from the cross rail  11  of the punching machine  1  to the remote tool magazine  17  is illustrated in  FIGS. 6 to 9 . By means of a corresponding movement of the cross rail  11  along the cross beam  9  of the coordinate guide  8 , the punching tool  15  to be transferred was previously arranged beneath the tool holder  24  moved into its receiving position close to the station. 
         [0039]    The tool holder  24  is located in the receiving position close to the station in  FIG. 6 . The tool gripper  25  is lowered vertically and has gripped the punching tool  15  detachably located at a storage place  14  of the cross rail  11 . 
         [0040]    Proceeding from the situation as shown in  FIG. 6 , the tool gripper  25  with the punching tool  15  affixed thereto is raised ( FIG. 7 ). The transfer carriage  27  with the tool holder  24  and the punching tool  15  is subsequently moved in the direction towards the rear end of the machine frame  3  until the tool holder  24  has reached its transfer position remote from the station and the punching tool  15  held at the tool gripper  25  is located above the storage place  20  provided for the punching tool  15  on the magazine platform  18  of the remote tool magazine  17 . The tool gripper  25 , together with the punching tool  15 , is now lowered and the punching tool  15  is thereby transferred to its assigned storage place  20  ( FIG. 8 ). The tool gripper  25  now releases the punching tool  15  and is subsequently raised into its vertical starting position ( FIG. 9 ). The tool transfer device  23  is thus ready for a further tool change. 
         [0041]    The punching machine  1 ′ shown in  FIGS. 10 and 11  differs from the punching machine  1 ′ shown in  FIGS. 1 to 9  in the structural design of the remote tool magazine remote and the structural design of the tool transfer device. 
         [0042]    The punching machine  1 ′ shown in  FIGS. 10 and 11  has a tool magazine  40  which is remote from the station and is movable in the longitudinal direction of the machine frame  3 . For that purpose the supporting structure  19  of the remote tool magazine  40  is guided jointly with the magazine platform  18  on guide rails  41 ,  41  extending in the longitudinal direction of the lower frame arm  4 . Four rows, each with six storage places  20  for punching tools  15 , are provided on the magazine platform  18 . A tool transfer device  43  comprises a tool holder  24  that is stationary in the longitudinal direction of the machine frame  3 . The tool holder  24  immovable in the longitudinal direction of the machine frame  3  is movably guided in the transverse direction of the machine frame  3  on a supporting frame  44  firmly connected to the machine frame  3 . The tool grippers  25 ,  26  can be raised and lowered in the vertical direction. 
         [0043]    In order to transfer a punching tool  15  from the magazine platform  18  of the remote tool magazine  40  to a storage place  14  on the cross rail  11 , the remote tool magazine  40  is positioned with its magazine platform  18  in the longitudinal direction of the machine frame  3  relative to the stationary tool holder  24  of the tool transfer device  43 . The positioning movement of the remote tool magazine  40  is generated by the coordinate guide  8 . For that purpose the remote tool magazine  40  is connected by means of a switchable coupling  45  ( FIG. 11 ) to the cross beam  9  and via the latter also to the cross rail  11  of the coordinate guide  8 . By moving the coordinate guide  8  along the machine frame  3  the magazine platform  18  of the remote tool magazine  40  can be positioned with respect to the tool holder  24  of the tool transfer device  43  in such a manner that the tool holder  24 , together with the tool gripper  26  provided for manipulating the punching tool  15  in question, is located in the receiving position above the relevant punching tool  15 . After the magazine platform  18  of the remote tool magazine has been positioned, the tool gripper  26  is lowered in the vertical direction and grips the punching tool  15 . Together with the punching tool  15  the tool gripper  26  is then raised. This produces the configuration shown in  FIG. 10 . 
         [0044]    Proceeding from this operational state, the coordinate guide  8  moves towards the rear end of the machine frame  3  until the relevant storage place  14  on the cross rail  11  is located beneath the punching tool  15  affixed to the tool gripper  26 . In so doing the remote tool magazine  40  connected to the cross beam  9  of the coordinate guide  8  is displaced towards the rear end of the machine frame  3 . By lowering the tool gripper  26  of the tool holder  24  into its transfer position, the punching tool  15  is then transferred to the storage place  14  provided for it on the cross rail  11 . 
         [0045]    Once the cross rail  11  has been fitted with the punching tools  15  required for the subsequent sheet metal processing, the coupling  45  is released and as a result the coordinate guide  8  is separated from the remote tool magazine  40 . The coordinate guide  8 , without out having to move the tool magazine  40  along with it, can then carry out the movements required for the sheet metal processing to be performed and the tool change at the punching station  7 , including movements in the longitudinal direction of the machine frame  3  ( FIG. 11 ). The remote tool magazine  40 , now disengaged from the coordinate guide  8 , remains in its rest position at the rear end of the machine frame  3 . In order to carry out a further tool change over, the remote tool magazine  40  can be retrieved from its rear end position by the coordinate guide  8 . 
         [0046]    A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.

Technology Category: 4