Abstract:
A handling apparatus for handling parts, in particular large-volume workpieces, and having at least two gripper modules which are disposed opposite one another at a horizontal carrier which can be moved relative to one another and which are driven by a motor. The handling apparatus is of modular design and having at least one carrier module forming the horizontal carrier and at least two gripper modules as components which can be assembled in modular form.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a handling apparatus for handling parts, in particular large-volume workpieces having at least two gripper modules which are disposed opposite one another at a horizontal carrier, which can be moved relative to one another and which are driven by a motor. 
     Handling apparatus of this kind are known in principle and are used, for example, in the automation of production lines, for example for handling engine blocks, cylinder heads, transmission cases and the like. For this purpose, the handling apparatus are attached to manipulators such as robots or loading portals. 
     In accordance with the prior art, these handling apparatus are typically configured for a specific gripping procedure and/or are geometrically designed for the part to be gripped. If different parts have to be moved, work is usually carried out using gripper changing apparatus to adapt the manipulator in an automated manner to the new gripping work by replacing the entire handling apparatus. Alternatively, the elements of the handling apparatus, that is, for example, the gripper arms, can be replaced or mounted at a new gripping position for the work to be carried out in the production line by a manual intervention of the plant operator. Such an exchange or a new installation in another orientation is, however, time-consuming and expensive. 
     Such a handling apparatus is known, for example, from DE 198 51 292 A1 in which a handling apparatus is described in the form of a gripping system for handling large-volume workpieces. With this gripping system, the position of the two clamping arms is adjusted with respect to one another by means of a motor via a right/left threaded spindle or the clamping arms are moved toward one another on the gripping of the workpiece. It is disadvantageous here that only the spacing of the clamping arms from one another can be modified and that in this respect the central position of the workpiece is displaced with asymmetrically designed workpieces. Furthermore only two clamping arms are also provided with this handling apparatus so that longer workpieces or asymmetrical workpieces cannot be picked up. 
     SUMMARY OF THE INVENTION 
     It is the object of the invention to further develop a handling apparatus of the category such that a handling apparatus is provided which has a safe function, but which allows parts differing with respect to their dimensions and which can be adapted flexibly to the handling work and to the respective pick-up or gripping points at the workpieces to be moved without the named handling apparatus having to be replaced in each instance. 
     This object is achieved in accordance with the invention by a handling apparatus which has the features herein. 
     The basic idea underlying the invention comprises the handling apparatus having a modular structure and at least comprising one carrier module forming the horizontal carrier and at least two gripper modules as components which can be assembled in modular form. The handling apparatus can hereby be assembled differently in accordance with the gripping work to be done. The entire handling apparatus does not have to be replaced in each case. It can preferably be adapted as fast as possible and in an automated manner to different gripping work by an automatic adjustment of the position of the gripping modules with respect to one another. The position of the gripping arms arranged at the gripping modules cannot only be oriented in a linear direction, but also in a plane. 
     Preferred embodiments of the invention result from the description herein. 
     The handling apparatus can accordingly have a corresponding number of drive modules depending on the number of the required linear movements of the carrier module and/or of the gripping modules. 
     The drive modules preferably comprise electric motors, in particular servomotors or stepper motors. 
     In accordance with an alternative embodiment of the invention, the drive modules can comprise hydraulic cylinders or pneumatic cylinders and/or electric motors. 
     Depending on the work of the drive module, it should either be capable of moving the gripper arm or the gripper module to and fro between two end points or of positioning the gripper module or the gripper arm at any desired position on the travel path. In accordance with the objective, either a positioning drive such as a servo motor or a stepper motor is thus then selected or a simple drive in the form of a hydraulic cylinder or of a pneumatic cylinder or of a simple electric motor is selected when it is only a question of the movement between two positions. 
     The connection to a robot or to a loading portal is provided via the carrier module. The carrier module can be rigid at its interface. In accordance with a special embodiment of the invention, it can, however, also be connected to the robot or to the loading portal via a controllable rotary connection so that the total gripper apparatus can be rotated about its vertical axis. 
     The gripper modules can preferably engage via guide shoes in a linear guide arranged at the carrier module. 
     When electric motors are used, the gripper modules can have racks into which the pinions engage which are driven by the electric motors. The corresponding linear movement can hereby be executed with high exactness. 
     The handling apparatus has, in accordance with an especially preferred embodiment of the invention, a control via which the carrier module or the gripper modules can be controlled independently of one another. Settings specific to the workpiece can therefore be made here due to the drive units respectively associated with said modules. 
     The gripper modules each have at least one gripper arm with which a separate drive can be associated in each case in turn as required. It is thereby possible that the gripper arm can, on the one hand, be moved together with the drive of the gripper module at which it is arranged. On the other hand, it can also be moved by its own drive relative to the gripper module. 
     In accordance with another preferred embodiment of the invention, the carrier module positions and/or the gripper module positions or the gripper arm position can be adjustable in a change-over station by external coupling of an adjustment device to the respective module. Change-over processes or refitting processes can therefore be carried out here due to the simple coupling of the adjustment device without having to replace the entire gripper modules. In this embodiment of the invention, the movement for opening and closing the gripper preferably takes place via a separate apparatus—e.g. hydraulic cylinders or pneumatic cylinders—at the handling apparatus. 
     The handling apparatus can also be coupled to the robot or to the loading portal via a compensation unit. It can be used to compensate a correction of a positional error between the workpiece and the gripper apparatus, both in the receiver and in the transfer position. 
     The carrier module has at least two installation positions to which gripper modules—also of different construction sizes—can be fastened. The corresponding gripper arms via which tool-dependent gripper insets can grip the workpiece can be arranged at the gripper modules. 
     To grip a workpiece in the loading position, the gripper inserts of the gripper arms have to be moved toward the workpiece. If the workpiece is gripped from the outside, the gripping movement takes place in that two gripper modules are moved toward one another at the carrier module. If the gripping positions are located within a workpiece contour, a reverse gripping movement takes place. 
     The linear movements of the gripper modules or of the carrier module, on the one hand, and of the gripper arms which are arranged at the gripper modules, on the other hand, are required for different functions. The movements first serve the setting of the arm position relative to the gripping points at the workpiece. An adjustment of the gripping arms in an X-Y plane is necessary depending on the tool size and on the gripping points at the workpiece. In the change-over mode, the base position of the gripper arms or gripper fingers is therefore set relative to the gripping position at the workpiece. In production operation, the gripper apparatus is typically then only positioned relative to the workpiece and the workpiece is gripped via a closing movement of the gripper arms. The workpiece is released from the gripper arms by an opposite movement of the gripper arms. 
     The handling apparatus in accordance with the invention has the possibility of positioning the workpiece exactly in the X-Y plane via a synchronous movement of the gripper arms. This can simplify the placement of the portal relative to the transfer positions since the latter then no longer have to be oriented so exactly transversely to the portal direction. This was already not a problem in the longitudinal portal direction in known units since the transfer position of the loading portal was adjustable in the longitudinal direction. 
     The linear movement at the carrier module, on the one hand, and at the gripper modules, on the other hand, can take place via different mechanisms. In addition to a motorized adjustment via electric motors which drive a rack via pinions, other mechanical drive units such as toothed belts can also convert the rotary movement of the motor into a linear movement. Controllable motors have the advantage that the position of the modules can be influenced very exactly via them. The position of the gripper modules relative to the carrier module can thus be changed via motors at the carrier module. Furthermore, both the gripper movement and a positioning movement of the gripper arms or of the gripped workpiece can take place. The same applies to drive units in the gripper modules. The position of the gripper arms mounted at the gripper modules can be set very exactly via said drive units. 
     In the change-over mode, the respective gripper arm can thus be set individually to the workpiece to be gripped or to its gripping position. In production operation, only the opening or closing movement of the gripper arms is mostly used, but with positioning work also being possible using these gripper arms. With very complex gripping operations, a gripping movement around collision contours at the workpiece can also take place by the separate controllability of the motors. The workpiece can in this respect, for example, also be fed into a clamping apparatus in that specific movements are carried out after one another. Further intermediate modules such as turning devices and the like for pivoting the workpieces can be fastened between the individual modules, that is between carrier modules and gripper modules, but also between the gripper modules and the gripper arms. 
     Thanks to the modularity of the handling apparatus it can be assembled individually depending on the required work. 
     Depending on the expansion stage, the handling device can, for example, be equipped with a manual adjustment device. Later, when a higher flexibility is required, motors for the gripper adjustment can then be retrofitted. The handling device can be adapted to the gripping work can be changed over to different gripping work by different construction sizes of the modules. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features, details and advantages of the invention will be explained in the following with reference to different embodiments shown in the drawing. There are shown: 
         FIG. 1 : a schematic plan view of the embodiment of the handling apparatus in accordance with the invention with a carrier module and two gripper modules; 
         FIG. 2 : a side view of the handling apparatus in accordance with  FIG. 1 ; 
         FIGS. 3 a -3 d   : a schematic representation of the modular handling apparatus in different expansion stages; 
         FIG. 4 : a schematic plan view of a further embodiment of the handling apparatus in accordance with the invention; and 
         FIG. 5 : a schematic plan view of a further embodiment of the handling apparatus in accordance with the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 and 2  respectively show a plan view and a side view of the modular handling apparatus  1  in accordance with the invention comprising a carrier module  16  which is connected to a loading portal or robot  15  via a connection piece  14 . 
     The connection piece  14  can be configured as rigid as is shown here. Alternatively, it can also be configured in the form of a rotary connection and/or compensation unit. It is possible with such a rotary connection to rotate the total gripping apparatus about its vertical axis (Z axis). Positional errors of the workpiece with respect to the transfer device can be compensated by the compensation unit. In the embodiment shown here, two gripper modules  17  and  18  of the same construction are connected to the carrier module via guide shoes  25  and a linear guide  26 . The gripper modules are in this respect arranged linearly movably at the carrier module. The linear movement of the gripper modules  17  and  18  takes place in the embodiment via servo motors  10  and  20  which each mesh with racks arranged at the gripper modules  17  or  18  by means of a pinion. The position of the individual gripper modules  17  and  18  can be controlled independently of one another via the servo motors  10  and  20  so that the position of the gripper modules  17  and  18  is individually adjustable. The adjustment in the Y direction takes place via a synchronous movement and thus allows a positioning of the workpiece relative to the handling apparatus  1  in the Y direction, that is in the direction of the longitudinal extent of the carrier module  16 . A gripping of a workpiece  24  not shown in more detail here takes place in that the gripper modules  17  and  18  are moved toward one another in a controlled manner. 
     The gripper modules  17  and  18  in turn allow the movement of the gripper arms  19  and  22  with the gripper fingers  21  and  23  fastened thereto along the axial direction of the gripper modules  17  and  18 . The gripper fingers  21  and  23  are in this respect the components contacting the workpiece for picking up the workpieces  24  (cf.  FIG. 2 ). 
     In the same way as with the carrier module  16 , the linear adjustment movement in the gripper modules  17  and  18  can take place in a motorized manner via the servo drives  30  and  40 . These motors move the gripper arms  19  and  22  over linear guides  25  and  26  in the axial direction of the gripper module. In the embodiment shown here, only one respective gripper arm  19  and  22  respectively is mounted per gripper module. Alternatively, two gripper arms  19 ,  19 ′ and  22 ,  22 ′ respectively per gripper module  17  and  18  respectively are mounted in the position shown in plan view in  FIG. 1 . The gripper arms are thus additionally still adjustable relative to one another so that they can be adapted to different gripping positions at the workpiece. A combination of one and two adjustable grippers or gripper arms per gripper module  17  and  18  is hereby also possible. These different variants are shown in the  FIGS. 3 a    to  3   d.    
       FIG. 3 a    schematically shows the simplest expansion stage of the handling apparatus  1  in accordance with the invention having a carrier module  16  and two gripper modules  17  and  18 . If only two gripper arms  19  and  22  are provided and if they do not have to be moved along the gripper modules with respect to the X direction, only two motors  10 ,  20  are required to open or close the gripper. The position can naturally also be varied in the Y direction on the joint movement of these two motors  10 ,  20 . In a further expansion stage, the adjustment possibility of the gripper arms  19 ,  22  can be provided in the X direction by the installation of one or two further drive units with the motors  30  and/or  40 . A retrofitting is also possible here by a subsequent installation of the drive units. 
     An alternative expansion stage of the handling apparatus in accordance with the invention is shown in  FIG. 3 b   , with a twin gripper being shown at the gripper module  18  here. In this embodiment, two gripper inserts  21  and  21 ′ are mounted at the gripper arm  19 , with the position of these two gripper inserts being fixed with respect to one another, that is, not being able to be adjusted. Only one gripper insert  23  is fastened to the oppositely disposed gripper arm  22 . In this embodiment, a total of four motors  10 ,  20 ,  30 ,  40  are arranged at the handling apparatus to be able to carry out linear axial movements in the X direction and the Y direction. 
     If the two gripper arms  19 ,  19 ′ at the gripper module  18  are mounted on two independent movement units, as is shown schematically in  FIG. 3 c   , a further drive unit having the motor  50  is required to realize the independent movement of the gripper arms  19  and  19 ′ at the gripper module  18 . A carrier module  16  having an installed drive unit with two motors is therefore shown here for adjusting the position of the two gripping modules in the Y direction as well as two motorized adjustments of the position of the two left hand gripper arms and a motorized adjustment of the right hand gripper arm at right angles to the adjustment direction (X direction) of the carrier module  16 . 
     The largest expansion stage of the handling apparatus  1  in accordance with the invention is shown schematically in  FIG. 3 d   . Here, a carrier module  16  having an installed drive unit with two motors for adjusting the position of the two gripper modules  17  and  18  in the Y direction as well as four motorized drive units for the independent adjustment of the position of the two left hand or right hand gripper arms respectively at right angles to the adjustment direction (X direction) of the carrier module are shown. Each gripper arm is thus moved separately via an associated drive unit having motors  10 ,  20 ,  30 ,  40 ,  50 ,  60  in the gripper module. The maximum possible freedom of movement of the gripper arms in the X-Y plane can hereby be realized. 
       FIGS. 4 and 5  show different construction sizes of gripper modules ( FIG. 4 ) and carrier modules ( FIG. 5 ). A gripper can be relatively simply configured for different sizes of workpieces by a selection and combination of different modules with one another. 
     A gripper apparatus having two gripper modules (I, II) of the same construction is disclosed at the left in  FIG. 4 . However, workpieces which have a considerably different extent to the right and to the left at their gripping positions can be gripped by installation of two gripper modules of different sizes at one carrier module. In this respect, the gripping position of the gripping modules (I, II) can be swapped as desired. The carrier modules  16  are also in different construction sizes, as is shown in  FIG. 5 . The handling apparatus can be configured very flexibly by this modularization and can thus be adapted very simply to different workpiece sizes in the first configuration or be set very simply in ongoing production operation within the framework of the adjustment paths to the different workpieces.