Abstract:
A device for fitting substrates with electric components includes a stationary carrier supporting a positioning device. The carrier is arranged above at least two fitting stations that are located one after the other in a conveying direction. A chassis of the device includes end supports and central supports that are connected to the carrier.

Description:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/DE01/01981 which has an International filing date of May 23, 2001, which designated the United States of America and which claims priority on German Patent Application number DE 100 25 443.8 filed May 23, 2000, the entire contents of which are hereby incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention generally relates to a device for fitting substrates with electric components. Preferably, the device includes at least one positioning device for a fitting head which can be moved in two coordinate directions for handling the components. 
   BACKGROUND OF THE INVENTION 
   A device has been disclosed, for example, by WO 9837744 A1. According to that document, the device has a linear transport having two fitting stations for the substrates. Between the two fitting stations, a beam-like carrier extends transversely to the transport direction of the substrates. Attached to the carrier on both sides are X-Y positioning devices which cover the fitting stations and the collecting points for the components. 
   The positioning device comprises a longitudinal guide fixed to the carrier and provided with magnetic parts, along which an upright positioning arm provided with a coil part can be moved, on which a fitting head for handling the components can be moved. The positioning arm, anchored on one side, has a relatively great free length. Rapid acceleration processes and in particular braking processes lead to oscillations in the positioning arm, which are disruptive in particular when the fitting head is in its end region. During each collecting or fitting operation, these oscillations must first have decayed before these operations can be carried out. 
   Feed modules for the components are lined up on both sides of the transport path in the direction of the positioning arms. Since the positioning arms must not become too long, the number of feed modules and therefore the multiplicity of components which can be provided are also limited. 
   SUMMARY OF THE INVENTION 
   An embodiment of the invention is based on an object of providing a device which, with a compact design, permits low-oscillation mounting of the fitting head. 
   Since the fitting head is now no longer arranged at the side of the fitting stations but above the latter, the stationary longitudinal guide can also be arranged through the center of the travel area, so that the movable positioning arm can be driven, guided and supported in a central section, for example via an integrated linear motor. The freely projecting sections are thus distributed on both sides of the longitudinal guide and remain correspondingly short and flexurally rigid. The result of arranging the positioning axes in the central region of the fitting area is very short lever arms during fitting, which increases the fitting accuracy. 
   As a result of arranging the carrier above the fitting plane, no supporting structures are needed in the travel area of the fitting head, so that the feed devices for the components can be brought up close to the fitting station. Because of the beneficial mounting conditions, the travel area in the direction of the row of the feed modules can be enlarged to such an extent that a considerably greater number of feed modules can be attached. 
   The dimensionally stable carrier can be connected firmly to the chassis by the end supports and the central supports, so that low-oscillation transmission of the accelerating and braking forces into the chassis is possible. 
   An advantageous development can include wall-like central supports. As a result of their extent in the transport direction, they stiffen the support of the carrier, in particular in this direction. As a result of their oblique inclination, the carrier in the central area is also supported particularly well in the transverse direction. 
   The wall-like end supports can stiffen the structure transversely with respect to the transport direction of the substrates. 
   The relatively slim supports can be arranged at a short distance from the outer edge of the travel area, which permits correspondingly compact external dimensions. 
   A plate-like carrier may be particularly flexurally rigid in the direction of travel and correspondingly exhibits little oscillation. The clearances in the corner regions make access easier to the interior of the device. 
   The chassis may be adapted to the position of the supports. The internal corners of the cross-like structure serve to accommodate feed modules for the components to be provided. 
   A low-oscillation casting may be produced cost-effectively. 
   Pneumatic units or units for power supply, for example, can be inserted into the hollow basic body. 
   The cavity in the basic body, extending underneath the conveying path, can be used for the installation of an additional transport path, on which substrates can be locked past the fitting stations belonging to the device. 
   A plate-like carrier may include an advantage that different positioning devices can be mounted in a different configuration. For instance, the fixed longitudinal axis of the positioning device can be oriented parallel to the conveying direction, with the positioning arm covering both feed areas for the components. 
   Further, it is also possible to arrange the fixed longitudinal guide transversely with respect to the conveying direction and above the fitting station, as a result of which the positioning arms can be kept shorter. Arranging two positioning arms on the common longitudinal guide allows for the fitting performance to be increased considerably, by the two positioning devices alternately collecting the components and placing them on the substrate. 
   The operating and control devices can be arranged to be easily accessible in a close association with the positioning devices. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in more detail in the following text using exemplary embodiments illustrated in the drawings, in which: 
       FIG. 1  shows a schematic perspective view of a device for fitting substrates with electric components, 
       FIG. 2  shows a partial section through the device according to  FIG. 1 , 
       FIG. 3  shows a partial section through a modified device according to FIG.  1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   According to  FIGS. 1 and 2 , a chassis  1  of a device for fitting substrates  6  with electric components  15  includes a cast basic body  2  and a plate-like carrier  3  which is fixed thereto and on which an X-Y positioning device  4  is mounted. Above the basic body  2 , a conveying path  5  for the substrates  6  is led through the device, it being possible for the substrates  6  to be fitted with the components in fitting stations  7  of the conveying path  5 . 
   In plan view, the basic body  2  has a cross-like structure, in which a main leg extends parallel to the conveying path  5  and underneath the latter. A central leg extends transversely with respect to the transport direction in the central area of the main leg. At its ends, wall-like central supports  8  projecting upward and obliquely with respect to each other are cast on for the carrier  3 . Provided at the ends of the main legs are end walls  9  which are attached in one piece and which, above the basic body  2 , are widened to form end supports  10  for the carrier  3 . Arranged in the corner regions between the legs of the basic body  2  are spaces for feed devices  11  for the components to be fitted. The upper sides of the feed devices  11  arc at the same vertical level as the substrate  6 . 
   The plate-like carrier  3  is arranged at a distance above the conveying path  5 . Mounted on its underside is the positioning device  4 , which includes a longitudinal guide  12  which is fixed to the underside of the carrier  3  and extends in the conveying direction, and a positioning arm  13  which is transverse thereto and which is detachably mounted in the longitudinal guide  12 . The latter is, for example, provided with magnetic parts which, together with a coil part belonging to the positioning arm  13 , form a linear motor which drives the positioning arm. 
   On the underside of the positioning arm, a turret-like fitting head  14  is detachably mounted, using which the components  15  can be transported from collecting stations  16  of the feed devices  11  to their placement locations on the substrate. The central supports  8  are so wide and flexurally rigid in the conveying direction that they effectively prevent oscillations caused by the movement of the positioning arm. Pulses triggered in the transverse direction by the movement of the fitting head are effectively prevented by the end supports. In order to achieve the highest possible fitting performance, it is expedient to assign a dedicated positioning device  4  for each fitting station. 
   Provided on the upper side of the carrier  3  are spaces for auxiliary devices, for example in the form of a control device  17  and a display  18 . The basic body  2  is formed as a cast hollow body, through whose main leg an additional transport path  19  for the substrates  6  is led. This conveying path is used, for example, to lock substrates past the fitting stations. The cavities in the central secondary legs can be used, for example, to accommodate power supply units, pneumatic equipment or further control devices. 
   The device according to  FIG. 3  differs from that according to  FIG. 2  in the arrangement of the positioning axes. The modified longitudinal guides  21  here extend transversely with respect to the conveying direction of the substrates over each of the fitting stations and are fixed to a modified carrier  23  reinforced by ribs. On the longitudinal guide  21 , two modified positioning arms  22  each having one of the fitting heads  14  can be moved. These form two positioning devices  20 , which can alternately collect components and place them on the substrate, as a result of which the fitting performance is increased considerably. 
   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.