Abstract:
A handling for components having a similar shape, particularly motor vehicle body parts, wherein a gripper on an arm of a robot can grip the component and its similarly-shaped other components with one and the same clamp device without re-tooling, is equipped with two gripper chucks on each clamp device. However, only one gripper chuck can be steered into the grab positions in each case, while the other gripper chuck is then located in the parking position outside a grab area on the component.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a National Phase Application of International Application No. PCT/EP2006/067246, filed on Oct. 10, 2006, which claims the benefit of and priority to German patent application no. DE 10 2005 049 494.3, filed Oct. 13, 2005, and German patent application no. DE 10 2006 025 844.4, filed Jun. 2, 2006. The disclosure of each of the above applications is incorporated herein by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to a handling system for components having a similar shape, particularly motor vehicle body parts, in which a gripper on the arm of a robot is equipped with several clamp devices having contour pieces adapted to the components, with which the respective component can be gripped on areas spatially staggered to one another. 
       BACKGROUND 
       [0003]    In motor vehicle body construction known handling systems (DE 202 19 713 U1) are used, wherein the component to be handled, for example a motor vehicle door, is gripped by means of a gripper on the arm of a robot and brought exactly to the place of the body structure, where it is to be assembled. So that the component is picked up securely and precisely, the gripper is equipped with several clamp devices, on their part each comprising a gripper chuck, which grip the component in several spatially staggered places with the contour pieces adapted to the component. A pre-condition for precise-position gripping requires that for each type of component the clamp devices on the gripper are positioned accordingly and equipped with suitable contour pieces. Such a device and change-over of the grippers are necessary even if components having a similar shape are to be handled. “Components having a similar shape” are understood to mean those, which although congruent in several places have a different height to each other. Alternatively a further suitably tooled handling system could also be used for another type of component, which however would be associated with a substantial increase in engineering costs. 
         [0004]    For opening and closing gripper chucks of handling systems mechanical drives, which have a toothed push bar, are known (U.S. Pat. No. 6,428,071 B2). The driving toothed push bar is formed as part of a hydraulic cylinder piston arrangement and is coupled to the movable gripper jaws of the gripper chuck via a fixed pinion. 
       SUMMARY OF THE INVENTION 
       [0005]    In general, in one aspect, the invention is to provide a handling system for components having a similar shape, particularly motor vehicle body parts, in which with one and the same gripper these components can be handled without laborious setting up and re-tooling. 
         [0006]    In one embodiment, a handling system includes clamp devices, each clamp device having two gripper chucks, whose gripper jaws can be pivoted from a parking position into a grab position, the gripper jaws of the gripper chuck being in their parking position whenever the gripper jaws of the other gripper chuck are pivoted into their grab position and vice versa. 
         [0007]    The invention is based on the realization that in the case of components having a similar shape there are places, which although cannot be gripped by the same gripper chuck with the same contour pieces, can be gripped by the other gripper chuck with other contour pieces. A pre-condition however is that gripping of the component by the one gripper chuck is not obstructed by the gripper jaws of the other gripper chuck, which lies in the way thus causing interference. According to the invention, this is accomplished by the alternate locking of the gripper chucks in the parking position lying outside the grab movement of the other gripper chuck. 
         [0008]    In order to set up a gripper for the components having a similar shape, according to one embodiment of the invention, it is proposed that the clamp devices are held by support arms, adapted in length, of the gripper. By pivoting and longitudinal adjustment of the support arms each clamp device can be matched to the congruent areas of the components having a similar shape on which they are to be gripped. The pairs of gripper jaws of each clamp device are then equipped in each case with contour pieces suitable for the two components having a similar shape. Thus compensation for different heights can also be made. 
         [0009]    Preferably, the gripper chucks of each clamp device respectively have a drive comprising toothed push bars. The toothed push bars of two gripper chucks, arranged adjacent to each other, of the same clamp device preferably can be alternately coupled to the same engaging pieces of the drive. The engaging piece itself is driven by a crank and rocker linkage mechanism. According to an alternative embodiment of the drive of the gripper chucks, the gripper jaws of the two gripper chucks can be pivotally and axially displaced on common bearing journals and, with drive pinions, can be coupled to a common driven toothed push bar. 
         [0010]    The special advantages of this other drive lie in its simple construction, which manages with only one toothed push bar for both gripper chucks. A further advantage consists in the fact that the same operating position is provided for both gripper chucks. 
         [0011]    In order to move the gripper jaws of the gripper chuck from their parking position into the operating position and the gripper jaws, located in the operating position, of the other gripper chuck into their parking position and vice versa, the gripper jaws are coupled to a common displacement drive. The displacement drive can have an actuator, displaceably mounted parallel to the bearing journals and driven by a servo motor, which is connected to the gripper jaws via engaging pieces. Preferably the servo motor is a cylinder piston arrangement, able to be impacted on both sides by a pressurizing medium and to whose piston rod the actuator is attached. The engaging pieces can be pins, which engage in coaxial annular grooves of the drive pinions of the gripper jaws. 
         [0012]    Since the invention proposes the same operating position for both gripper chucks, the guidance of the now active gripper chuck and the locking of the inactive gripper chuck are simply constructed, by guidance flanks being provided on both sides for the gripper jaws of each active gripper chuck, whose drive pinions now exactly engage with the toothed push bar, said guide flanks being effective during the pivot movement of said gripper jaws, and by lateral holding pockets being provided for the gripper jaws of each then inactive gripper chuck, whose drive pinions do not then engage with the toothed push bar. 
         [0013]    Since only one common toothed push bar is provided for both gripper chucks, the toothed push bar can be constantly coupled to the drive. According to one embodiment of the invention, it is propulsively connected to the piston rod of a cylinder piston arrangement via a pinion and an elbow lever coupled thereto. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0014]    The invention is described in detail below with reference to a drawing illustrating two exemplary embodiments, wherein individually: 
           [0015]      FIG. 1  shows contours of two components having a similar shape, a front and a rear door of a vehicle body adjacent to each other, 
           [0016]      FIG. 2  shows the contours of the components having a similar shape of  FIG. 1  one above the other, 
           [0017]      FIG. 3  shows a handling system with a gripper in side view, 
           [0018]      FIG. 4  shows the gripper of the handling system viewed in the direction of arrow Z of  FIG. 3  with several clamp devices adjusted to the congruent contours of the front and rear door, 
           [0019]      FIG. 5  shows the gripper of  FIGS. 3 and 4  in perspective illustration, 
           [0020]      FIG. 6  shows one of the clamp devices of the gripper according to  FIG. 3  in its structural make-up, in perspective illustration, whereby one half of its clamshell housing is removed, 
           [0021]      FIG. 7  shows a detail of the clamp device of  FIG. 6 , and to be precise a gripper chuck with its drive, in perspective illustration, 
           [0022]      FIG. 8  shows a detail of the gripper chuck of  FIG. 7  in schematically simplified illustration, 
           [0023]      FIG. 9  shows one of the clamp devices of  FIG. 3  in an embodiment, alternative to  FIGS. 6 to 8 , in perspective illustration, whereby one side of its clamshell housing is removed, 
           [0024]      FIG. 10  shows the clamp device in accordance with  FIG. 9  in side view, 
           [0025]      FIG. 11  shows the clamp device in accordance with  FIG. 10  in partial section along line I-I, 
           [0026]      FIG. 12  shows the clamp device in accordance with  FIG. 10  in partial section along line II-II of  FIG. 10 . 
       
    
    
     DESCRIPTION 
       [0027]      FIG. 1  on the left illustrates the contour of a first component, a front door of a motor vehicle, and on the right the contour of a similarly-shaped second component, to be precise the rear door. In  FIG. 2  the two contours are drawn one above the other. In this illustration the congruent areas are illustrated as dotted lines. These congruent areas are also suitable for gripping the component with one and the same clamp device. 
         [0028]    The handling system illustrated in  FIG. 3  has a robot  1 , which carries a gripper  3  on its arm  2 . This gripper  3  can be moved by the robot  1  in the space about a plurality of axes. The gripper  3  has a base  4  with arms  5 ,  6  arranged pivotally thereon and adapted in length, which at their end carry a clamp device  7 ,  8  in each case. The clamp devices  7 ,  8  are, according to  FIG. 4 , positioned on the congruent areas of the similarly-shaped components to be handled, again marked as a dotted line. With this positioning it is possible to grip the front door  9  illustrated in  FIG. 3  on the left, but also the rear door  10  illustrated on the right, although the rear door  10 , also within the congruent areas, has a different height to the front door  9 . Compensation for the different height and contour of the components within the areas to be gripped is made by special contour pieces. In this case the gripper  3  can grip the components both from their concave side (component  9 ) and also from their convex side (component  10 ). 
         [0029]    All clamp devices  7 ,  8  of the gripper  3  have the same structure. As  FIG. 6  shows, each clamp device  7 ,  8  has two gripper chucks  11 ,  12  with gripper jaws  11   a ,  11   b ,  12   a ,  12   b  which in each case pivot around 90°. These gripper jaws  11   a  to  12   b  can be expanded with contour pieces (not illustrated), which are adapted to the contour of the component to be gripped. The pair of gripper jaws  11   a ,  11   b  for example are provided for the component A, e.g. the front door  9 , while the other pair of gripper jaws  12   a ,  12   b  are provided for the component B, e.g. the rear door  10 . While the pair of gripper jaws  12   a ,  12   b  are located in the grab position, the pair of gripper jaws  11   a ,  11   b  are in the parking position, where they are held by locking means, for example a ball catch consisting of a spring-tensioned ball in the housing and a recess in the gripper jaws  11   a ,  11   b . In  FIG. 6 and 8  these recesses  12   a * and  12   b * are only visible for the gripper jaws  12   a ,  12   b . Other locking means of a pneumatic, hydraulic, electromagnetic type or combinations thereof are possible. A toothed push bar  13 ,  14 , which combs with toothed segments  14   a ,  14   b ,  15   a ,  15   b  of the pivoting gripper jaws  11   a ,  11   b ,  11   b ,  12   a ,  12   b , serves to pivot the two pairs of gripper jaws  11   a ,  11   b ,  12   a ,  12   b  around 90° in each case. The two toothed push bars  13 ,  14  are driven by a common drive, which consists of a rotary cylinder  16  and a rotational part  17 . In order to couple the two toothed push bars  13 ,  14  alternately to the crank and rocker linkage mechanism  17 , an engaging piece  18  illustrated in  FIGS. 7 and 8  coupled to the crank of the crank and rocker linkage mechanism  17 , with a controllable clutch element  19 , formed as cylinder piston arrangement, which can be impacted on both sides by a pressurizing medium, is arranged between the two toothed push bars  13 ,  14 . The controllable clutch element  19 , with journals  20  of its piston  21 , enables either the toothed push bar  13  or the toothed push bar  14  to be coupled to the crank of the crank and rocker linkage mechanism  17 . Since in respect to the clamp device  7 ,  8  it can be ensured that whenever the gripper jaws  12   a ,  12   b  are in the grab position, the gripper jaws  11   a ,  11   b  are located in the parking position and thus do not lie in their path of movement, the component can be gripped without problem. If the other component is to be gripped, the gripper jaws  12   a ,  12   b  are pivoted back by 90° into the parking position, while the gripper jaws  11   a ,  11   b  are pivoted into the grab position. This means that with one and the same clamp device  7 ,  8  components having a similar shape can be gripped on the congruent areas, without the gripper jaws provided for the one component obstructing the gripping of the other component by the other gripper jaws and vice versa. 
         [0030]    As is the case for the exemplary embodiment of  FIGS. 6 to 8  first described, all clamp devices  7 ,  8  of the gripper  3  have the same structure also in the case of the second exemplary embodiment of  FIGS. 9 to 12 . However the drive of their gripper jaws  11   a ,  11   b ,  12   a ,  12   b  and their locking device in the parking position are different. While the pair of gripper jaws  12   a ,  12   b  are in the grab position, the pair of gripper jaws  11   a ,  11   b  are in the parking position, where in the case of the second exemplary embodiment they are held by lateral holding pockets  21   a ,  21   b ,  22   b.    
         [0031]    For pivoting the gripper jaws  11   a ,  11   b ,  12   a ,  12   b  of each gripper chuck  11 ,  12  a toothed push bar  23 , with teeth on both sides, is propulsively connected to a piston rod  26   a  of a cylinder piston arrangement  26  via a pinion  24  and an elbow lever  25 , coupled thereto. This toothed push bar  23  serves to drive the gripper jaws  11   a ,  11   b ,  12   a ,  12   b  of both gripper chucks  11 ,  12 . Different from the main patent, the gripper chucks  11 ,  12  can be moved to alternately engage with the toothed push bar  23  via the drive pinions  27   a ,  27   b ,  28   a ,  28   b  of their gripper jaws  11   a ,  11   b , to  12   a ,  12   b . For this purpose the gripper jaws  11   a ,  11   b ,  12   a ,  12   b , pivotally mounted on their bearing journals  29   a ,  29   b  can also be axially displaced on these bearing journals  29   a ,  29   b . A pneumatic drive, which has a cylinder piston arrangement  30  with a piston  30   a , able to be impacted on both sides by a pressurizing medium, and a piston rod  30   b , which is coupled via a crosshead  31  to two axially displaceable journals  32   a ,  32   b  is provided for the common axial displacement of the gripper jaws  11   a ,  11   b ,  12   a ,  12   b . Each journal  32   a ,  32   b  has two pins  32   b *,  32   b **,  32   a * acting as engaging pieces, which engage in annular grooves of the drive pinions  27   a ,  27   b ,  28   a  of the gripper jaws  11   a ,  11   b ,  12   a ,  12   b.    
         [0032]    The gripper jaws  11   a ,  11   b ,  12   a ,  12   b  are changed over in the following way: all gripper jaws  11   a ,  11   b ,  12   a ,  12   b  are in the open position. In this position the pair of gripper jaws  11   a ,  11   b  located in the holding pockets  21   a ,  21   b  in the lateral parking position can be moved into the central position, the operating position, while the other pair of gripper jaws  12   a ,  12   b  are transferred into the other lateral holding pockets  21   a ,  22   b  in the parking position and can be securely held here. During this change-over the first pair of gripper jaws  11   a ,  11   b  with their drive pinions  27   a ,  27   b  are moved to engage with the toothed push bar  23 , while the other pair of gripper jaws  12   a ,  12   b  with their drive pinions  28   a ,  28   b  are disengaged from the toothed push bar  23 . The pair of gripper jaws  11   a ,  11   b  moved thus into the central middle position, namely in the operating position, can now be pivoted by the toothed push bar  23 , being laterally guided through guide flanks formed by the housing, while the other pair of gripper jaws  12   a ,  12   b  are positively held in the associated holding pockets  22   b.