Abstract:
In automatic placement machines having a forced guidance, feed modules are guided displaceably on the automatic placement machine in the longitudinal direction using a precision bearing in a manner exhibiting play, and also having a precision guidance separate therefrom, by which the feed modules can be positioned without play in an end region of the precision bearing.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a precision bearing for feed modules of automatic placement machines.  
           [0003]    2. Description of the Related Art  
           [0004]    On an automatic placement machine there are arranged a plurality of feed modules which are able to feed a wide variety of placement elements to the automatic placement machine during the placement process. In order to be able to ensure high placement accuracy, it is necessary that the feed modules can be positioned exactly on the automatic placement machines, for example by exact strips onto which the feed modules are placed. Moreover, it is desirable to be able to exchange the feed modules during the operation of the automatic placement machine, without the operation being able to be disrupted. Furthermore, disturbances in the positioning accuracy of the feed modules can occur as a result of placement elements accumulating on the bearings of the feed modules in the automatic placement machines and therefore preventing exact insertion of the feed modules.  
         SUMMARY OF THE INVENTION  
         [0005]    An object of the invention is to provide a precision bearing for feed modules of automatic placement machines which enables exact positioning of the feed modules on the automatic placement machine and also fault-free exchange of the feed modules during the operation of the automatic placement machine, without disturbances on account of deposited placement elements being able to occur.  
           [0006]    The object is achieved by a precision bearing for feed modules of automatic placement machines, including a forced guidance portion to guide the feed modules in a manner exhibiting play displaceably on the automatic placement machine in a longitudinal direction of the feed modules, and a precision guidance portion to position the feed modules without play in an end region of the precision bearing.  
           [0007]    The invention provides a precision bearing for feed modules of automatic placement machines which has a forced guidance portion and a precision guidance portion. In the forced guidance portion, the feed modules are guided in a manner exhibiting play and displaceably on the automatic placement machine in the longitudinal direction of the feed modules. In the precision guidance portion, the feed modules can be positioned without play in an end region of the precision bearing. In this case, the separation of forced guidance and precision guidance affords the advantage that an inexact forced guidance can also be designed with fault tolerance with respect to deposited placement elements and nevertheless restricts the freedom of movement of the feed module in the event of an exchange during the operation of the automatic placement machine to the extent that reliable operation of the automatic placement machine is ensured. Exact positioning of the feed module on the automatic placement machine is necessary only in an end region of the precision bearing in order to make available to the placement process a collection position for placement elements on the feed module with high accuracy.  
           [0008]    The precision guidance portion can be designed in such a way that in the end region it takes up essentially all of the bearing forces. In this case, the play-exhibiting forced guidance portion can be completely relieved of the bearing forces, and transfer the bearing forces to the precision guidance portion, thereby avoiding mechanical redundancy.  
           [0009]    Moreover, the end region of the precision bearing may be coupled to the forced guidance portion via a transition element. By way of example, the transition element may have a ramp-like design. This enables the feed module to be pushed into the end region of the precision bearing securely and without jolting.  
           [0010]    The precision guidance portion may have bearing elements with inclined areas, which are each formed on the automatic placement machine or on the feed module and can be coupled to one another to receive the feed module. The effect that can be achieved by the use of inclined areas for the precision guidance portion is that a desired position is automatically assumed, without play, due to the weight force of the feed module.  
           [0011]    By way of example, the inclined areas have an angle of inclination of 45°. The bearing elements can thus be of M-shaped or V-shaped design, i.e., have an M- or V-shaped cross section, and extend in the longitudinal direction of the feed modules.  
           [0012]    The inclined areas may adjoin one another and are in this case formed in such a way that, in the coupled state of the bearing elements of the automatic placement machine and of the feed modules, a cavity in each case remains at the bottom between two inclined areas of the automatic placement machine. Deposited placement elements can accumulate in the cavity without the positioning accuracy of the precision guidance being impaired.  
           [0013]    By way of example, in the forced guidance portion feed modules may each have at least one dovetail-like groove which tapers toward the bottom of the groove, and the forced guidance portion may include at least one sliding block whose form essentially corresponds to the groove, where the groove and the sliding block are formed in such a way that when the sliding block is arranged in the groove, a cavity remains at the bottom of the groove. The cavity at the bottom of the groove enables deposited placement elements to accumulate in the cavity without the function of the forced guidance being adversely affected. As a result of the tapering of the groove toward the bottom of the groove, deposited placement elements are deposited at the bottom of the groove and thus, when the sliding block has been pushed in, are located in the cavity. The grooves are preferably arranged on the automatic placement machine and the sliding block is in each case arranged on the feed modules. The sliding block may be provided with a wipe-off device by which objects, for example deposited placement elements, can be removed from the groove when it is pushed in and out of the groove.  
           [0014]    In addition, the precision bearing may be provided with a precision hole in the vicinity of the end region and a positioning pin, which can engage essentially without play into the precision hole. By way of example, the precision hole may be formed in the automatic placement machine and the positioning pin may be formed on the feed module.  
           [0015]    By virtue of the combination of precision guidance, precision hole and positioning pin, an even higher degree of accuracy for positioning the feed modules can be achieved in the end region of the precision bearing.  
           [0016]    Moreover, by virtue of the invention&#39;s forced guidance in the longitudinal direction of the feed modules, the feed modules, when inserted into and withdrawn from the automatic placement machine, can execute movements essentially only in the longitudinal direction during the operation of the automatic placement machine. The risk of damage to the automatic placement machine and thus disruption of the operation of the automatic placement machine due to a collision between the feed modules and moving assemblies of the automatic placement machine is avoided. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]    The invention is explained in more detail with reference to the drawing, in which  
         [0018]    [0018]FIG. 1 is a diagrammatic perspective view of components—arranged on an automatic placement machine—of a precision bearing according to a preferred embodiment of the invention;  
         [0019]    [0019]FIG. 2 is a diagrammatic perspective view of the preferred embodiment of the invention;  
         [0020]    [0020]FIG. 3 is a diagrammatic perspective view of components—arranged on a feed module—of the precision bearing according to the preferred embodiment;  
         [0021]    [0021]FIG. 4 is a sectional view through part of the precision guidance according to the preferred embodiment;  
         [0022]    [0022]FIG. 5 is a sectional view through part of the forced guidance according to the preferred embodiment of the invention; and  
         [0023]    [0023]FIG. 6 is a perspective diagrammatic view of the forced guidance according to the preferred embodiment with feed module pushed into the end region. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0024]    [0024]FIG. 1 reveals components of the preferred embodiment of the invention which are arranged on an automatic placement machine. As can be seen from FIG. 1, a plurality of dovetail-like grooves  210  are arranged parallel to one another and next to one another on the automatic placement machine. Each of the dovetail-like grooves  210  is provided with a ramp region  260 , which facilitates the insertion of a sliding block fitted, for example on a feed module of an automatic placement machine. Bearing areas  170  are formed near the ramp region  260  of the dovetail-like grooves  210 . The bearing areas  170  provide bearing locations for the feed modules positioned by the precision guidance according to the preferred embodiment of the invention. Provided in the vicinity of the end region E are bearing elements  110  having an M-shaped cross section, for example, and also ramp regions  160 , which facilitate the insertion of a feed module into the end region E of the precision bearing according to the preferred embodiment. The bearing elements  110  form part of the precision guidance portion. Furthermore, adjoining the end region E, provision is made of stop areas  310  for feed modules and also precision slot holes  320 .  
         [0025]    [0025]FIG. 2 shows a feed module  300  pushed into the precision bearing according to the preferred embodiment of the invention. In this case, a sliding block  220  fitted on the feed module  300  engages into the dovetail-like groove  210  on the automatic placement machine. The ramp region  260  in the initial region of the dovetail-like grooves  210  enables simple insertion of the feed module  300  into the groove  210 . At its front end region, the feed module  300  is provided with a bearing element  120 , which essentially corresponds to the form of one of the bearing elements  110  of the precision guidance portion. When the feed module  300  is pushed into the groove  210 , the bearing element  120  fitted on the feed module  300  slides over the ramp region  260  into the bearing element  110  of the precision guidance portion, the bearing element being fitted on the automatic placement machine. The feed module  300 , once it has been pushed in, can furthermore be engaged by a positioning pin  330  (evident from FIG. 4) inserted into one of a plurality of positional slot holes  320  which are provided in a manner adjoining a stop  310  for the feed module  300  on the automatic placement machine. By way of example, the positioning pin may be of cylindrical design and be fitted on the end area of the feed module which faces the precision slot hole  320  in the pushed-in state of the feed module.  
         [0026]    In the pushed-in state, the feed module  300  merely rests by the bearing element  120  on the bearing element  110 , and also by its rear end region on the bearing location  170 . The forced guidance is not subjected to loading in the pushed-in state of the feed module  300 .  
         [0027]    [0027]FIG. 3 reveals a detail view of the sliding block  220  which is arranged on the feed module  300  and essentially corresponds to the form of the groove, and also of the bearing element  120  which can engage into the bearing element  110  of the precision guidance portion. Corresponding cross sections of the bearing element  110  of the precision guidance portion and also of the dovetail-like grooves  210  of the forced guidance portion can be seen in FIGS. 4 and 5, respectively. The bearing element  120  arranged on the feed module  300  and the bearing element  110  of the precision guidance portion are in this case formed in such a way that, with the bearing element  120  engaging into the bearing element  110 , a cavity remains at the bottom of the bearing element  110  at those locations at which the inclined areas of the bearing element  110  adjoin one another. Deposits, such as placement elements for example, can accumulate in the cavity without the positioning accuracy of the precision guidance being impaired.  
         [0028]    Equally, the sliding block  220  and the dovetail-like groove  210  are formed in such a way that, when the sliding block  220  has been pushed into the groove  210 , a cavity remains at the bottom of the respective groove, in which cavity deposits, such as placement elements for example, can accumulate without the mode of operation of the forced guidance being adversely affected.  
         [0029]    [0029]FIG. 6 reveals a detail of a feed module  300  in its end position in the precision bearing according to the preferred embodiment of the invention. In this case, the sliding block  220  fitted on the feed module  300  has been completely inserted into the groove  210 . The sliding block  220  does not touch the groove  210 . This is ensured by the feed module  300  being borne, in the end position, by the precision guidance with the bearing elements  120  and  110  (not shown in FIG. 6) and also by the bearing location  170 . This makes it possible to avoid mechanical redundancy.  
         [0030]    As can be seen in FIG. 6, a cavity  250  remains at the bottom of the groove  210 , in which cavity deposits can accumulate without adversely affecting the mode of operation of the forced guidance.  
         [0031]    A wipe-off device may be fitted on the sliding block  220 , by which device placement elements deposited in the groove  210  can be removed during insertion and removal of the sliding block  220  from the groove  210 .