Abstract:
The invention relates to a holding device for holding at least one optical plug that can be coupled with a coupling partner in an optical coupling system. According to the invention, the holding device comprises an inner holding part ( 11 ) into which the plug ( 3 ) can be locked and an outer holding part ( 12 ) in which the inner holding part ( 11 ) is arranged so as to be rotatable and laterally displaceable. The holding device enables a coupling of an optical plug with a coupling partner even for the case in which the coupling partner is situated with an imprecise position.

Description:
BACKGROUND OF THE INVENTION 
     FIELD OF THE INVENTION 
     The invention relates to a holding device for holding at least one optical plug that can be coupled with a coupling partner in an optical coupling system. 
     It is known to couple an optical plug, having a plurality of light waveguides arranged parallel to one another, with a coupling partner, with the aid of a holding device. Coupling partners are for example optical transmission and/or reception modules that are arranged on a circuit board, or, rather, optical ports/plug receivers formed on said modules. 
     With the use of high transmission frequencies in the Gbit/s range, it is thereby standard to arrange an optical transmission module and an optical reception module next to one another on a circuit board. These modules situated closely alongside one another have completely separate manners of functioning, and are also situated in different housings, in order to ensure a mutual shielding and to avoid cross-talk. Correspondingly, the optical connections to each module are created through separate plugs. 
     For functional reasons and for reasons of safety, it is desirable to couple or, respectively, decouple the two optical plugs for the two modules with, or from, the respective coupling partner at the same time. For this purpose, from EP-A1-0 807 837 it is known to arrange the two optical plugs in one holding device. However, the problem thereby arises that the modules (transmission and reception module) situated in a fixed manner on the circuit board do indeed have a definite, relatively precisely defined spacing from one another, but this spacing however naturally possesses a tolerance that is high in comparison with the precision that is required (a few m) for the coupling of the light waveguides of an optical plug with the light waveguides of the coupling partner. In this way, there arises the risk that the coupling partners cannot be coupled with one another with the required precision, or that tensions will occur in the system, caused by different spacings of the plugs in the holding device and of the modules on the circuit board. 
     SUMMARY OF THE INVENTION 
     Accordingly, the invention is based on the object of providing a holding device, for holding at least one optical plug, that reliably enables a coupling of an optical plug with a coupling partner even for the case in which the coupling partner is subject to tolerances in its position. 
     According thereto, it is inventively provided that the holding device comprises an inner holding part into which the plug can be locked and an outer holding part in which the inner holding part is situated so as to be rotatable and laterally displaceable. A coupling of the plug or plugs with a coupling partner thereby takes place in that an operator grasps the outer holding part, with the plug or plugs situated therein, and moves it in the direction of the coupling partner until the coupling partners lock with one another in a known manner. 
     Due to the circumstance that the inner holding part is arranged in the outer holding part so as to be rotatable and laterally displaceable, the inventive holding device thereby provides a tolerance compensation in relation to a coupling partner that is arranged with a positional tolerance. In this way, a lateral offset of the coupling partner can be compensated by the lateral displaceability of the inner holding part in the outer holding part, and an angular offset of the coupling partner can be compensated by the rotatability of the inner holding part in the outer holding part. 
     Due to the inherent high precision of the coupling system, as a rule it is sufficient to provide a relatively small rotatability, of a maximum of a few degrees, and a relatively small lateral displaceability, of a maximum of one millimeter. 
     In a preferred construction of the invention, the outer holding part comprises at least one elongated hole in which a bearing pin of the inner holding part engages. The elongated hole thereby provides both a rotatability of the inner holding part and also a lateral displaceability of the inner holding part in relation to the outer holding part. The elongated hole thereby preferably extends transverse to the plug-in direction of a plug. 
     In the preferred construction of the invention, the holding device holds at least two plugs, each of which is fixed in an inner holding part, whereby the outer holding part is fashioned in one piece and with receive openings for receiving a respective inner holding part, and whereby each inner holding part is arranged in the respective receive opening of the outer holding part so as to be rotatable and laterally displaceable. This construction provides in particular a duplex holding device that receives two plugs, for example for coupling an optical transmission module and an optical reception module arranged at a defined distance therefrom. Due to the rotatability and lateral displaceability of the inner holding part in the outer holding part, the two plugs can pivot and/or move laterally in the holding device in order to compensate a positional tolerance of the two coupling partners. 
     The outer holding part is thereby preferably fashioned in such a way that the individual receive openings are separated from one another by a partition wall. In addition, the outer holding part is preferably provided on its outside with a ribbing, in order to enable it to be grasped better and more securely. 
     The inner holding part preferably comprises a locking element that works together with complementary structures of the plug in order to lock an optical plug in or out. The optical plug is thereby arranged in the inner holding part essentially without play. A compensation of positional tolerances of the coupling partner takes place via the inventive arrangement of the inner holding part in the outer holding part. 
     The locking element of the inner holding part comprises for example a locking clip that, when an optical plug is introduced into the inner holding part, comes to rest on a stop of the plug. 
     It is thereby preferably provided that the outer holding part comprise at least one opening via which, using a tool, the locking element of the inner holding part can be actuated from the outside, thereby enabling the unlocking of a plug that is fixed in the inner holding part. In this way, a simple unlocking and removal of an optical plug from the inner holding part is enabled. 
     In the following, the invention is explained in more detail on the basis of an exemplary embodiment, with reference to the figures of the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a perspective view of an inner holding part of an inventive holding device; 
     FIG. 2 shows a different perspective view of the holding part of FIG. 1; 
     FIG. 3 shows a perspective view of a known optical plug; 
     FIG. 4 shows a perspective view of two optical plugs according to FIG. 3, each arranged in an inner holding part according to FIGS. 1,  2 ; 
     FIG. 5 shows a perspective view of an outer holding part of an inventive holding device; 
     FIG. 6 shows the arrangement of the inner holding parts with optical plug according to FIG. 4 in the outer holding part of FIG. 5, and 
     FIG. 7 shows the arrangement of FIG. 6 with a transmission module and a reception module as coupling partners of the optical plug. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIGS. 1 and 2, an inner holding part  11  of an inventive holding device is shown that is used to receive a known optical plug  3  according to FIG.  3 . 
     According to FIG. 3, the plug  3  comprises a multiplicity of light waveguides  31  for parallel optical data transmission that terminate in planar fashion at a front side  32  of the plug  3 . The light waveguides  31  enter from the rearward end of the plug  3  as a common tape cable  33 . For coupling with a coupling partner (cf. FIG.  7 ), locking arms  34  are provided that are each provided with a locking projection  35  and a ridge  36  that runs transversely, whereby both the locking projection and also the ridge comprise a leading incline. The rearward end of the locking arms passes over into an actuation region  39  that can be actuated by an operator in order to unlock the plug  3  from a coupling partner. 
     In addition, on its housing surface the plug forms a sliding ridge  37  with which the plug can slide along on corresponding surfaces of the inner holding part  11 . The sliding ridge  37  is fashioned with interruptions, thus providing a stop  37   a  for a locking connection with the inner holding part  11 . At the end of the sliding ridge  37  close to the cable, a transverse ridge  38  is situated that, when the plug  3  is introduced, limits the plug-in depth of the plug  3  by stopping against an end face of the inner holding part  11 . 
     The inner holding part  11  of FIGS. 1 and 2 is essentially cuboidal in construction and comprises an insert opening  111  for receiving an optical plug  3 . In the area of the insert opening  111  it comprises a semicircular lateral openings [sic]  112  that ensure that when the plug  3  is introduced into the inner holding part, an operator will have sufficient access to the actuation area  39  of the locking arms  34 . 
     In addition, the holding part  11  has a locking clip  113  coupled in spring-loaded fashion to the holding part, said clip forming at its end a locking projection  113   a  and being situated in an opening  114  of holding part  11 . Said clip comes to a stop, with the locking projection  113   a,  behind the stop  37   a  of the sliding ridge  37  (cf. FIG. 3) when the plug  3  is introduced into the inner holding part  11 , and in this way fixes the plug  3  in the inner holding part. 
     The dimensions of the inner holding part  11  and the plug  3  are such that the plug  3  is fixed in the inner holding part  11  essentially without play. 
     For connection with an outer holding part  12  (cf. FIG. 5) of the holding device, a protruding bearing pin  115  is fashioned on the upper side of the inner holding part  11 . A correspondingly positioned bearing pin is also fashioned on the underside of the holding part  11 . 
     FIG. 4 shows, in a duplex arrangement, two optical plugs  3  that are each arranged in an inner holding part according to FIGS. 1 and 2. The locking clip  113  of the inner holding part is thereby respectively locked in behind the stops  37   a  of the plugs. The front side  32  of the plugs, with the light waveguide ends  31  that are to be coupled, protrudes somewhat from the inner holding part  31 , in order to enable simple insertion into the plug receptacle of a coupling partner. 
     An outer holding part  12  of the inventive holding device is shown in FIG.  5 . The outer holding part  12  comprises two receive areas  121 ,  122 , each of which receives an inner holding part  11  in corresponding receive openings. The two receive areas  121 ,  122  are separated from one other by a partition wall  123 . An elongated hole  124  is fashioned in each receive area  121 ,  122 , on the upper and lower housing wall. 
     The elongated hole  124  is used for the respective reception of a bearing pin  115  of the inner holding part. After locking of the bearing pin  115  of an inner holding part into the elongated holes  124 , the inner and outer holding part are connected with one another. The connection is thereby inventively such that the inner holding part  11  is on the one hand rotatable in the outer holding part  12  and is on the other hand displaceable transverse to the plugging direction. In this way, these two degrees of freedom are provided by the coupling of the bearing pin with the elongated hole. 
     It is hereby pointed out that the elongated hole character of the elongated holes  124  in FIG. 5 is not very pronounced, since only a small lateral displaceability of the inner holding part is required. 
     The outer holding part  12  is provided with a ribbing  125  in order to enable better grasping of the outer holding part  12 . In addition, in each receive area an opening or, respectively, a through-hole  126  is provided in the holding part  12 . This opening is used to enable the locking clip  113  of the inner holding part to be lifted using a tool, for example a screwdriver, and thereby to effect an unlocking of the plug  3  from the inner holding part  11 , while the inner holding part  11  is situated in the outer holding part  12 . 
     In FIG. 6, the inventive holding device  1  is shown with two inner holding parts  11  introduced into the outer holding part  12 , and with two optical plugs  3  respectively fixed in the inner holding part  11 . The bearing pins  115  are thereby respectively locked into the elongated holes  124 . For the coupling of the two plugs  3  with a respective coupling partner, the overall system is grasped by an operator at the outer holding part  12  and is moved towards the coupling partners, whereby the plugs lock into corresponding plug receptacles of the coupling partners. 
     In FIG. 7, as coupling partners plug receptacles  41 ,  51  of a known optical transmission module  4  and of an optical reception module  5  are shown. The two modules  4 ,  5  are fastened next to one another with a defined spacing on a circuit board (not shown). Their spacing and their orientation to another thereby necessarily have a certain positional tolerance. 
     Nonetheless, on the basis of the inventive holding device it is possible to introduce the plugs  3  into the plug receptacles  41 ,  51  with the required precision of a few μm, since, through the rotatability and lateral displaceability of the inner holding part  11  in the outer holding part  12 , it is possible to compensate an offset between the two plugs  3  that are to be coupled jointly and the two modules  4 ,  5 . 
     The actual coupling between the plugs  3  and the plug receptacles  41 ,  42  takes place in a known manner through corresponding guide surfaces and mutually engaging guide grooves and ridges, as well as the locking arms  34  of the plugs  3 .