CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the priority benefits of German Application No. 10 2006 025 272.1 filed May 31, 2006. 
   BACKGROUND OF THE INVENTION 
   The invention relates to a tool gripper arrangement provided for the automatization of processes particularly for large compartment stage presses. The workpiece gripper arrangement is particularly suitable for an automatic tool change. 
   “Tooling” in a press, particularly a large compartment stage press such as a vehicle body press, are the elements adapted specifically to the metal sheets or other organs of the press such as the gripper arrangements. The gripper arrangements are used, for example, for the transfer of metal sheets from one press to the next and for placing the metal sheet parts into the respective press stage and the removal thereof, from the respective press stage. The gripper arrangements may be, for example, suction arms or similar devices. The suction arms comprise several suction cups which are supported by several arms of a support frame. The suction cups are adapted in shape to the contour of the metal sheet parts. The suction arms are moved by a drive arrangement, for example, a transfer device. The transfer device includes various support beams which extend transverse to the transport direction, so called girders on which the tooling, that is the gripper means in the form of a frame from which the arms with the suction sups extend are supported. During a tool change, generally also, the tooling needs to be changed. 
   It is the object of the present invention to provide a workpiece gripper arrangement wherein a tool change can be performed automatically in a simple manner. 
   SUMMARY OF THE INVENTION 
   The present invention provides a workpiece gripper arrangement for the automatization of presses, including a transfer arrangement for transferring components between workstations, the transfer arrangement includes a girder or carrier with gripper means for holding the components and the gripper means is supported via coupling parts of which one is connected to the girder and the other to the gripper means and a mechanical locking structure is provided which is operable by relative movement of the coupling arrangement with respect to a support frame on which the gripper means can be deposited. 
   The workpiece gripper arrangement includes gripping means, for example, in the form of a suction spider and a girder or carrier, for example, in the form of a support beam wherein the carrier is connected to the gripper means via a coupling arrangement. The coupling arrangement comprises a mechanical locking structure which can be locked or unlocked by an operator. The operator can be activated by a relative movement of the coupling arrangement against a stop wherein the relative movement causes a release of the locking structure when the operator is activated by the relative movement. 
   With this arrangement, movements of the carrier provided by the drive arrangement can be used for the coupling and uncoupling of the coupling arrangement. The drive arrangement is present in any case, in order to move the carrier and, together therewith the gripper means to the workpiece. The drive arrangement is preferably such that the carrier is movable in various spatial directions including along its longitudinal axis and transverse thereto. The movement in the transverse direction can be utilized for the actuation of this operator if a stop is engaged thereby. The movement in the longitudinal direction can be altered for the coupling or uncoupling of the gripper means that is for the opening and closing of the coupling structure. 
   With the proposed solution, it is consequently possible to utilize for the automatic tool exchange the axes of the transfer arrangement. Active couplings or active locking devices with corresponding remotely controlled actuators are not required. The fact that no drive means are needed for the coupling arrangement reduces the weight of the coupling arrangement whereby the dynamics of the transfer arrangement can be improved. 
   The coupling arrangement, particularly the carrier-side coupling part, may be slidably supported on this carrier by means of a linear guide structure. The coupling arrangement may be provided with a drive device for the movement of the gripper arrangement in the longitudinal direction of the carrier. In this way, driving the transport of the metal sheets, the metal sheets or other workpieces can be adjusted in the longitudinal direction of the carrier. Furthermore, the linear guide arrangement can be utilized in connection with a drive arrangement to execute the coupling movement. 
   Preferably, the coupling part associated with the gripper arrangement includes an arresting structure by which the gripper arrangement can be deposited in a storage structure, for example, a support frame or a storage cart. The arresting structure is preferably activated by a relative movement between the gripper arrangement and the storage structure. The relative movement in that case is, for example, transverse to the longitudinal carrier, for example, in a vertical direction. In a simple embodiment the arresting structure is framed by indexing bolts which are provided on the support frame and which are capable of moving into corresponding openings in the coupling part associated with the gripper arrangement. 
   The coupling arrangement is formed preferably by coupling parts which engage each other wherein one coupling part includes one or several fingers which extend parallel to the carrier that is in the direction of the coupling or uncoupling movement. The fingers or other longitudinal projections are received in recesses in the other coupling port. The recesses again are provided with locking members which are part of the arresting structure, for example, in the form of locking bolts which can extend into openings in the fingers. The locking bolts lock the fingers in the respective associated recesses when they extend into the openings in the respective fingers. 
   The locking bolts can be operated by an actuating pin section forming the operating structure. The locking bolts and, consequently, the operating structure are oriented in a direction transverse to the carrier and consequently, transverse to the coupling and uncoupling arrangement. When the operating structure abuts a stop and the carrier is moved together with the coupling arrangement in a transverse direction, the operating structure and, as a result, the locking bolt is moved to the release position. In this way, the locking can be engaged with, or disengaged, from the carrier supply by an approximate control of the drive means for the transfer arrangement. 
   Advantageous embodiments of the invention will be described below with reference to the accompanying drawings. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows schematically presses with a transfer unit; 
       FIG. 2  is a prospective view of the transfer unit according to  FIG. 1  with a transverse carrier and tooling; 
       FIG. 3  shows schematically part of a coupling arrangement of the transfer arrangement according to  FIG. 2  together with an associated storage structure; 
       FIG. 4  shows the coupling arrangement according to  FIG. 3  in a partially sectional side view; 
       FIG. 5  shows the coupling arrangement according to  FIGS. 3 and 4  deposited on the storage structure with locking structure unlocked; 
       FIG. 6  shows the coupling arrangement according to  FIG. 5  during unlocking, and; 
       FIG. 7  shows the locking structure and the storage structure after deposition of the tooling arm on the storage structure in a partial schematic side view. 
   


   DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1  is a highly schematic representation of a press installation  1  including two presses  2 ,  3  and a transfer arrangement  4  including a transfer unit  5 . The transfer unit  5  is provided for transferring workpieces, for example, sheet metal parts, particularly large sheet metal parts, such as, motor vehicle body parts, from the press  2  to the press  3  or to an interim storage location which is not shown herein. The press installation  1  may comprise a single press, two presses as shown in  FIG. 1  or several presses. The transfer arrangement  4  may comprise one or several transfer units  5 . The transfer arrangement is adapted to move one or several girders  6  which form a carrier for a gripper means  7 . The gripper means  7  may comprise, for example, several suction spiders  8  as shown in  FIG. 2 . The transfer unit  5  as shown herein includes a support arm  10  having arm sections  12 ,  13  joined by a joint  9 . For a controllable movement of the arm sections  12 ,  13 , drives  14 ,  15  are provided and also other drives which are not shown so that the guider  6  can be moved in horizontal and vertical directions as desired and can also pivoted in selected directions. The drives  14 ,  15  form, together with the other drives which are not shown, a drive arrangement  16 . The drive arrangement  16  may additionally include an adjustment drive structure  17  by which the suction spider  8  is movable longitudinally along the girder  6 . The adjustment drive structure  17  is optional. It may be omitted in particular in connection with transfer units which permit a movement of the guider  6  on a horizontal transverse direction that is in the longitudinal direction of the girder  6 . 
   The suction spider  8  comprises a frame  18  including two support tubes extending parallel to the girder  6 . From the support tubes, tubular arms ( 19 ,  20 ,  21 ,  22 ,  23 ,  24 ) extend, which each carry a suction cup ( 25 ,  26 ,  27 ,  28 ,  29 ,  30 ). The suction cups are, for example, in the form of downwardly open dished rubber elements which can be evacuated via the tubular arms  19  to  24 . 
   For depositing the suction spider  8  on the girder  6 , a coupling arrangement  31  is provided at one end of the frame  18 . Another coupling arrangement may be provided at the other end or there may be a connecting structure  32  which comprises two parts  32   a,    32   b,  which engage each other in a form-locking manner or are disengaged by relative movement in axial direction along the girder  6 . 
   The coupling arrangement  31  is suitable particularly for depositing the tooling in the form of the suction spider  8  on a passive support frame with the aid of movements provided by the transfer unit  5  of the girder  6  by the drive arrangement  16  which are present anyway, and which are provided to position the girder  6  in the space for the transport of the workpiece. 
     FIG. 3  shows the coupling arrangement  31  on the girder  6 . Below the girder  6 , there is a linear guide structure  33  via which the coupling arrangement  31  can be moved longitudinally along the girder  6 . Part of the linear guide structure  33  is a guide track  34  which is oriented parallel to the girder and supported thereby and on which a carriage is movably supported. The coupling arrangement  31  comprises a first coupling part  36  which is connected to the carriage moveably supported on the guide track  34  or directly to the girder  6 , and a second coupling part  37  which carries the frame  18 . As shown in  FIG. 4 , a pin  38  extends from the coupling part  37  parallel to the girder track  34  or to the girder  6  into a bore or other opening  39  with little play. The pin  38  is in engagement with a locking structure  40 . For locking the pin  38  including, at its end, a recess, for example, in the form of a groove  41  which may extend around the pin  38 . A locking bolt  42 , which is part of the locking arrangement, is slidably supported in another bore  43  which extends transversely to the other opening  39 . The opening  39  intersects the bore  43  at an angle of about  90  degrees and outside the center thereof. While the opening  39  extends preferably parallel to the girder  6  the bore  43  extends in transverse direction thereto, preferably vertically. 
   The locking bolt  42  includes a blocking section  44 , whose diameter corresponds to the diameter of the bore  43  and to the curvature of the groove  41 . From the blocking section  44  an operating pin section  45  extends axially with a diameter which is so small that the operating pin does not pass through the bore when, as shown in  FIGS. 5 and 6 , it is in an upper position. The operating pin section  45  forms an operating member by way of which the coupling arrangement  31  can be released from the locked position into a release position in which the coupling parts are released from each other. 
   The locking bolt  42  is biased by spring  46  disposed in the bore  43  or by another suitable means into its locking position in which the blocking section  44  intersects the bore  39 . 
   The coupling part  37  includes an indexing bore  47  which extends parallel to the bore  43  that is transverse to the girder  6  the indexing bore  47  is adapted to receive an indexing bolt  49  which projects from a support frame  48  preferably vertically upwardly. The coupling part  37  may be provided on each side of the girder  6  with a corresponding indexing bore and a corresponding number of indexing bolts may be provided in appropriate positions for reception in the indexing bores. 
   In addition to the indexing bolt  49 , a stop  50  is provided, in the form of a release plate  51  which has a flat top surface  52  extending in a direction transverse to the indexing bolt  49 . This surface  52  may be a plane surface. It extends preferably parallel to the pin  38 . The unlocking plate can be received in a recess  53  formed in the bottom area of the coupling part  36  and adapted to receive the release plate  51 . The operating pin section  45  of the locking bolt  42  extends into the recess  53 , but not beyond the recess  53  as shown in  FIGS. 3 and 4 . 
   The transfer unit  5  described herein operates as follows with regard to a tool change: 
   it is assumed, as indicated in  FIG. 2 , that first a suction spider  8  which is supported on the girder  6  is to be exchanged. The support arm  10  moves the girder  6  over a support frame  48 , as shown in  FIG. 3 , and lowers the girder  6 . As a result, the coupling part  37  is disposed onto the indexing bolt  49  which moves into the indexing bore  47 . The pin operating sections  45  in the process abuts the surface  52  of the release plate  51  and is moved relative to the coupling part  36  against the force of this spring  46  to its release position. This state is shown in  FIG. 5 . The blocking section  44  is pushed out of the bore  39 . The blocking section  45  does not extend into the groove  41 . by which the pin  38  is released. The head  38   a  of the pin  38  can be moved past the pin. operating section  45 , that is, the pin  38  can. be pulled out of the bore  39 . To achieve this, the transfer unit  5  moves the girder  6  in the longitudinal direction of the girder as shown in  FIG. 6 . Alternatively, the drive structure  17  which can engage the coupling part  36  can be activated in order to initiate the axial movement of the coupling part  36  and cause the uncoupling. In this procedure, the front surface of the pin operating section  45  slides along the surface  52  of the release plate  51 . 
   When the pin  38  has been moved out of the bore  39 , the transfer unit  5  moves the girder  6  upwardly while the tooling remains disposed on the support frame  48 . This state is shown in  FIG. 7 . 
   For coupling the same or another tooling, that is a suction spider  8  to the girder  6 , the procedure is reversed. 
   For automatically changing the tooling only the already available movements capabilities along the axes of the transfer unit  5  are needed in accordance with the arrangement according to the invention. Neither active coupling structures nor active locking structures are needed or provided. A support frame  48  includes one or more indexing bolts  49  for guiding and fixing the tooling and one or several release plates  51  for unlocking the locking structure  40 . The locking structure  40  may also be formed by a locking bore whose bore intersects a reception bore for a coupling pin  38 . The locking bolt  40  is pre-tensioned into its locking portion and can be moved to the release portion when its narrow operating section  45  abuts the release plate  51 . The release movement for actuating the locking bolt  42  is transverse to the girder  6  whereas the coupling and uncoupling movement is parallel to the girder  6 . 
   The coupling arrangement  31  preferably includes fluid couplings which are oriented parallel to the coupling bolts or pins  38  serve as vacuum or air pressure transmitters to the suction spider. If necessary, additional media couplings may be provided. Furthermore, electrical couplings for current transfer or for the transmission of control signals and/or information signals for the sensors or for the activators may be provided. In addition, couplings for information covers, such as light conductors, may be provided wherein the coupling and uncoupling direction is always in the longitudinal direction of the girder  6  or, respectively, the longitudinal direction of the pin  38 . Such a coupling arrangement  54  is shown in  FIG. 3  schematically by dashed lines.
A workpiece gripper arrangement for the automatization of presses, including a transfer arrangement for transferring components between workstations, the transfer arrangement includes a girder or carrier with gripper means for holding the components and the gripper means is supported via coupling parts of which one is connected to the girder and the other to the gripper means and a mechanical locking structure is provided which is operable by relative movement of the coupling arrangement with respect to a support frame on which the gripper means can be deposited.