Abstract:
Substrates can be transported on a top transporting section to component-fitting locations of a component-fitting apparatus. Conveying sections for substrates which are to be routed past the component-fitting locations are arranged on a number of conveying levels beneath the transporting section.

Description:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/DE00/04418 which has an International filing date of Dec. 12, 2000, which designated the United States of America and which claimed priority on German patent application no. 19960799.0 filed Dec. 16, 1999, the entire contents of which are hereby incorporated by reference. 
   FIELD OF THE INVENTION 
   The invention generally relates to an apparatus for fitting electrical components on substrates. Preferably, it is possible for the substrates, in at least one transporting section of a top level, to be transported to a component-fitting location and away from the same. In addition, installation locations for additional conveying sections for the substrates are preferably provided beneath the transporting section. 
   BACKGROUND OF THE INVENTION 
   EP 0 413 089 A has disclosed a continuous installation for handling piece goods, in the case of which a plurality of handling sections are arranged, with a large amount of time being required, in segments parallel to one another, the piece goods being divided up thereon. 
   A component-fitting apparatus with additional conveying sections for the substrates has been disclosed, for example, by WO99/59389 A. According to the latter, the additional conveying sections are intended to subdivide long assembly lines into a plurality of segments in which a printed circuit board can be fitted out completely in each case. Provision is made here for an additional transporting level to be introduced beneath a component-fitting section, two conveying sections located one beside the other on said transporting level serving for feeding the substrates to the sub-segments and for removing the finished substrates from the sub-segments. Transfer arrangements are arranged upstream and downstream of the sub-segments and can transfer the substrates between the various sections. This means that the transfer arrangement has to be capable of displacement not just in height but also laterally, which is associated with a correspondingly high level of drive-related and guidance-related outlay. 
   In particular in the case of wide printed circuit boards, it is necessary to provide, for the two conveying sections, an installation width which results in an increase in the structural width of the component-fitting apparatus and thus in an increase in the standing surface area. There is thus also an increase in the distance between the component-fitting area and the peripherally provided feed arrangements for the electrical components. The displacement paths of a component-fitting head become correspondingly larger, as a result of which the component-fitting capacity decreases. 
   SUMMARY OF THE INVENTION 
   An object of an embodiment of the invention is to reduce the amount of space required as well as the apparatus-related outlay. 
   As a result of the two conveying sections being arranged on two levels located vertically directly one above the other, the transfer arrangements only have to be displaced in one direction, as a result of which the design outlay decreases. Since the substrates, in the form of flat printed circuit boards, are usually of a low overall height, the distance between the conveying sections can be kept small, with the result that the displacement paths are considerably shorter than in the case of lateral displacement. The installation width for the conveying sections can be more or less halved, as a result of which the component-fitting apparatus may be of correspondingly compact design. 
   The transverse connecting parts can make it possible to stabilize the chassis of the component-fitting apparatus in the immediate vicinity of the component-fitting level, with the result that there is no adverse effect to the component-fitting accuracy even in the case of a relatively large free space for the conveying sections. The transverse connecting parts may serve, at the same time, as bearing means for the transporting section or for a component-fitting table of the transporting section. 
   Short height intervals between the various sections can result in short displacement paths, with the result that the transfer device can be displaced quickly between the various levels. 
   A development can make it possible for turned substrates to be transported back in a space-saving manner within the component-fitting apparatus to the start of a component-fitting line and guided through the component-fitting line again in order for the second substrate side to be fitted out. All the conveying sections, including the return section, may be combined in a single compact arrangement and served by the transfer arrangements. Just one additional conveying section is necessary here for the return section, and the travel of the transfer device merely has to be increased to a slight extent. 
   The form of the chassis can result in a straightforward structure which can easily be produced by casting and is of high rigidity and dynamic strength. 
   The inspection opening can allow access to the conveying sections in the case of disruption. 
   The carrier can allow external assembly of the conveying sections including all the drives, actuating devices and control devices. This results in a fully prefabricated conveying module which can easily be pushed into the free space available. It is advantageous here for the supporting bearings to be arranged on the two end sides of the component-fitting apparatus, with the result that the carrier can be fastened at easily accessible locations. 
   The channel-like cross section of the carrier can result in a dimensionally stable load-bearing structure with low production outlay. It is possible for turned substrates to be transported back in a space-saving manner within the component-fitting apparatus to the start of a component-fitting line and guided through the component-fitting line again in order for the second substrate side to be fitted out. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in more detail hereinbelow with reference to an exemplary embodiment illustrated in the drawings, in which: 
       FIG. 1  shows, schematically, a longitudinal section through two component-fitting apparatuses which follow directly one after the other and have transfer arrangements, and 
       FIG. 2  shows a cross section through the component-fitting apparatus according to  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   According to  FIGS. 1 and 2 , transfer arrangements  2  are arranged on both sides of two component-fitting apparatuses  1  following one after the other, the transfer arrangements being provided with vertically displaceable transfer devices  3  for substrates  4 . On a top component-fitting level, the component-fitting apparatus  1  has a transporting section  5 , in the central region of which there is arranged a component-fitting location  6 , above which a component-fitting head  7  can be displaced in two coordinate directions. The component-fitting head  7  serves for fetching electrical components  8  from feed arrangements  9  and positioning them on the substrate  4 . 
   The component-fitting apparatus  1  has a chassis  10 , which is designed, beneath the transporting section  5 , as a chassis part  11  of rectangular tubular cross section. The chassis part  11 , which is open at both ends, forms a free space  12  with installation locations for conveying sections  13 , which run vertically beneath the transporting section  5  and parallel to the latter. The transfer device  3  can be displaced vertically between the transporting section  5  and the conveying sections  13  and can introduce the substrates  4  into the various sections and discharge them therefrom. 
   There are three conveying sections provided one above the other, of which the uppermost one serves as a feed section for the substrates which have not been fitted, the central one serves as a removal section for the finished substrates  4  and the lowermost one serves as a return section for substrates  4  which are fitted out on one side and can be introduced into the transporting section  5  in a turned state in order for the second substrate side to be fitted out. 
   The chassis part  11  has lateral inspection openings  14  through which, in the case of disruption, the inner segments of the conveying sections  13  are accessible. The conveying sections  13  are retained in a carrier  14  which is bent in the form of a U and, together with the preassembled conveying sections  13 , can be pushed longitudinally into the free space  12 . The carrier  14  is fastened on supporting bearings  15  on both end sides of the chassis  10 . The transporting section  5  is provided on the top side of the tubular chassis part  11 , with the result that the top tube wall is located between the transporting section  5  and the conveying section  13  located therebeneath. 
   LIST OF DESIGNATIONS 
   
       
         1  Component-fitting apparatus 
         2  Transfer apparatus 
         3  Transfer device 
         4  Substrate 
         5  Transporting section 
         6  Component-fitting location 
         7  Component-fitting head 
         8  Component 
         9  Feed arrangement 
         10  Chassis 
         11  Chassis part 
         12  Free space 
         13  Conveying section 
         14  Carrier 
         15  Supporting bearing 
         16  Inspection opening 
     
  
   The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.