Abstract:
A connector ( 6 ) includes a device ( 11 ) for securing it to a bulkhead or panel ( 14 ) of an enclosure. The device comprises a steel retaining clip ( 11 ) which is pushed over each jackpost ( 9 ) of the connector ( 6 ) and engages in a slot ( 10 ). the clip retains the connector ( 6 ) against the bulkhead ( 14 ) while a mating connector is attached, without the need for any nut and bolt arrangement or bulkhead fixing screws.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to improvements in electrical connectors of the type shown in FIG.  1  and sometimes known as “MDM” or “D microminiature” connectors. 
     2. Discussion of Prior Art 
     The known connector type  1  of FIG. 1 is provided with two or more rows of sockets or pins  2  which, on the reverse side are provided with contacts for soldering to pads on a printed circuit board or onto flying leads, for example. Two jackposts  3  with internal screw-threads are provided for securing a mating connector thereto. 
     The pine  2  and jackposts  3  are usually inserted through a cut-out in a bulkhead and the entire connector is fastened to the bulkhead by screws which are located in holes  4  provided in end flanges  5 . 
     The mating connector is usually attached to a cableform and carries two jackscrews which screw into the jackposts  3 , thereby holding the two connectors together. 
     In cases where space is limited it is not always possible to secure the connector  1  to the bulkhead by screws (or nuts and bolts). For instance, there may not be enough space on the bulkhead to accommodate any necessary holes, or there may be so little space behind the connector that the installation is impossible or very difficult. 
     In other applications where the connector  1  is attached to a printed circuit board via a flexible printed circuit board or flying leads, there is a need for a means of supporting the connector against a bulkhead while a mating connector is being secured thereto. 
     SUMMARY OF THE INVENTION 
     This invention aims to provide a means for supporting a connector while a cableform is being mated, without the need for bulkhead screws or bolts. 
     Accordingly, an electrical connector for mounting within a bulkhead comprises a chassis and a retaining clip, the chassis carrying electrical connection means and at least one jackpost for engagement with a co-operating part of a mating connector, in which the jackpost incorporates a slot for receiving the retaining clip which, in use, rests on an edge of the bulkhead. 
     In one embodiment the slot in the jackpost is a tangential slot and the retaining clip is substantially U-shaped. 
     In an alternative embodiment, the slot in the jackpost comprises a circular groove and the retaining clip is ring-shaped. 
     The retaining clips may preferably be made of spring steel, stainless steel or beryllium copper and can conveniently be made by either a photo-etching or pressing process. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Some embodiments of the invention will now be described, by way of example only with reference to the drawings of which; 
     FIG. 1 is a perspective view of a MDM known connector; 
     FIG. 2 is a perspective view of a MDM connector of the type shown in FIG. 1 but modified in accordance with a first embodiment of the invention, 
     FIG. 3 is a perspective view of a first type of retaining clip, 
     FIG. 4 is a perspective view of the connector of FIG. 2 assembled in a bulkhead, 
     FIG. 5 is a cross-sectional view along a line V-V 1  of FIG. 4, 
     FIG. 6 is a side view of a MDM connector of the type shown in FIG. 1 but modified in accordance with a second embodiment of the invention, 
     FIG. 7 is a plan view of a second type of retaining clip, and 
     FIG. 8 is a perspective view of an assembly tool for use with the connectors of FIGS. 2 and 6. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring to FIG. 2, the MDM-type connector  6  shown here comprises a chassis  7  which carries two rows of electrical sockets  8  and two jackposts  9 , these being the features in common with the standard connector of FIG.  1 . In contrast with the standard connector, the jackposts  9  of the device of FIG. 2 each incorporate a tangential slot  10 . The slot is cut in the lead-in portion of each jackpost  9  rather than the threaded portion in order to maintain mechanical integrity. 
     The purpose of each slot  10  is to receive a retaining clip  11  as shown in FIG.  3 . In this example, the clip  11  is etched from stainless steel and is substantially U-shaped. One arm  12  of the U-shape (which is straight) engages in the slot  10  with its outer surface protruding from the slot  10  sufficiently to engage with an edge of or recess in a bulkhead. The other arm  13  of the U is curved to follow the contours of the jackpost  9 . The clips  11  are thin compared with the height of the jackposts  9 . 
     FIGS. 4 and 5 show the connector  6  located in a cut-out in a bulkhead or panel  14 . The jackposts  9  and the part of the connector which carries the sockets  8  protrude through the bulkhead  14  with the extremities of the connector chassis  7  abutting the bulkhead  14 . The retaining clips  11  are shown located in their respective slots  10  with their outer surfaces resting on an edge of a recess  15  formed in the bulkhead  14 . 
     With the retaining clips  11  in place, the connector  6  is now retained in the bulkhead  14  and cannot fall out. Once in place, a mating connector can be secured and screwed into the jackposts  9 . Thus there is no need for any screws for securing the chassis  7  to the bulkhead  14 , and if desired, the holes  4  and end flanges  5  of the standard connector can be dispensed with. 
     In an alternative embodiment, the bulkhead  14  is not recessed and the clips  11  rest on the bulkhead&#39;s upper surface. 
     The clips  11  may be located on the jackposts  9  with the assistance of a telescopic tool to be described with reference to FIG.  8 . It is necessary to ensure that each clip  11  is passed over the jackpost  9  ie so that the straight arm  12  of the U-shape engages with the slot  10  and with the bulkhead. 
     The arrangement of the first embodiment described above requires the tangential slot  10  to be positioned at a specific location on the jackpost  9  with respect to the connector  6  (so that the arm  12  of the clip  11  can rest on the bulkhead). This can be achieved by cutting the slot after the jackposts have been assembled into the connector body. However, removal of the ensuing swarf may pose a problem. Alternatively, the slots can be cut before assembly, but then lining up the slotted jackposts to their correct positions within the connector body could be time consuming. 
     The arrangement of the second embodiment overcomes the above problems by providing a continuous groove in each jackpost, rather than a slot. In this case a ring-shaped clip can be used and can be positioned over the jackpost, either way round, to engage with the groove. 
     Referring then to FIG. 6, a connector body  16  supports an electrical socket housing  17  and two jackposts  18 . Each jackpost  18  incorporates a continuous, circumferential groove  19 . Each groove  19  is cut into the lead-in portion of each jackpost  18  rather than the threaded portion, in order to maintain mechanical integrity. 
     Each groove  19  receives a ring-shaped clip which can be etched from stainless steel for example. An example of a preferred form of clip is shown in FIG.  7 . 
     In FIG. 7 a retaining clip  20  is essentially circular and C-shaped, incorporating at least one protuberance for engagement with a bulkhead. The clip  20  of FIG. 7 incorporates two such protuberances in the form of tags  21 . The dimensions of the tags  21  depend on the spacing between the jackposts  18  and the bulkhead in which the connector  16  is to be mounted. 
     The thickness and inner diameter of the clips is chosen so that they fit snugly around the jackpost  18  within the groove  19 . 
     Alternative forms of ring-shaped clip could be elliptical rather than circular and/or dispense with tags and rely on a sufficiently large outer diameter for engagement with a bulkhead. In the case of an elliptical clip, it is preferred that the diameter of the minor axis of the ellipse is the same as the diameter of the grooved portion of the jackpost and that the inner circumference of the clip is slightly greater than the circumference of the uncut portion of the jackpost. 
     In a similar fashion to the U-shaped clip of FIG. 3, a ring-shaped clip can be located on a jackpost by means of a telescopic tool, now to be described with reference to FIG.  8 . 
     A rod  22 , preferably cylindrical, incorporates a flared portion  23  at one of its ends and a locating stub  24 , connected to the flared portion for alignment with a jackpost. The rod  22  is arranged to be a sliding fit within the bore of a second cylinder  25 . 
     In use, a clip  11  is manually fitted over the rod  22  and pushed along the length of the rod until it reaches the flared portion  23 . The end of the rod  22  distant from the flared portion  23  is inserted into the second cylinder  25  and the locating stub  24  inserted into the bore of a jackpost. The cylinder  25  is then pushed along the rod  22  and it makes contact with the clip  11 , continues to push the clip over the flared portion  23 , thus causing the clip to expand sufficiently so that it slides over the jackpost. Further movement of the cylinder  25  with respect to the rod  22  will push the clip off the flared portion  23  and over the jackpost until it snaps into the jackpost slot. 
     The tool of FIG. 8 is preferred over the conventional means comprising the use of pliers for the following reasons. Firstly the clip is not expanded to the same degree, thus leasing the risk of breakage, and secondly, there is less likelihood of the clip springing off the tool and creating an eye hazard, for example. 
     The tool can be used for fitting retaining clips to a variety of structures, its use not being limited to the example described herein. In certain cases, the locating stub  24  may be superfluous and could therefore be dispensed with.