Abstract:
For an electrical plug-in connector, particularly a multi-pole knife-type connector having a collar surrounding the plug-in ends of the contact elements, further contact elements are incorporated into the sides of the collar, the contact elements being accessible from the outside of the collar for mating electrical contact with corresponding contacts of a mating plug.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to an electrical connector, and more particularly, a multi-pole knife-type plug-in connector of substantially rectangular form having a carrier body of insulating material. Contact elements or pins, disposed in rows and columns, are inserted in a bottom part of the body. The body includes a collar which surrounds the plug-in area and the contact elements. 
     Such connectors are used as circuit board plug-in connectors and are known from Standard IEC 603-2. 
     SUMMARY OF THE INVENTION 
     The invention aims at further developing this type of plug-in connector so that the number of contacts available is increased substantially without any substantial increase in the overall dimensions of the plug-in connector. It is intended also to ensure that existing standardized mating plugs can be fitted together with the plug-in connector. 
     The invention achieves its aim in that in addition to the inner rows of contacts there is provided a further row of contacts with contact ends in the region of the collar. Longer sides of the collar are provided with recesses in which the contact ends are housed so that lateral surfaces of the further contacts are accessible from outside the collar for mating contact with corresponding contact elements of a mating plug. 
     The advantages achieved thanks to the invention consists particularly in that the number of plug-in contacts available with the plug-in connector has been substantially increased without the external dimensions being increased. In this respect, it is particularly advantageous that a conventional standard mating plug can be fitted to the plug-in connector in specific applications where there may be no need for the increased number of contacts. A further advantage lies in a further development of the invention in that the contacts of the outer rows of contacts are rigidly held in the protective collar. 
     An embodiment of the invention will now be described by way of example with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a plug-in connector according to the invention; 
     FIG. 2 is a partial perspective view of the under side of the plug-in connector according to FIG. 1; and 
     FIG. 3 is a view of the contact fixing in cross-section. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The plug-in connector shown in FIGS. 1 and 2 consists essentially of a carrier body 1 of insulating material with a bottom part 2 in which there are pin-shaped contact elements 3. The contact elements are disposed in known manner in columns and rows and their plug-in side 4 is enclosed by a rectangular collar, sleeve or shroud 5. The plug-in connector is intended for use with a circuit board 6 and the connection ends 7 of the contact elements are turned through a right-angle and fit into corresponding holes in the circuit board. 
     The geometry of the collar and the disposition of the contact elements is such that a commercially available mating plug in accordance with Standard IEC 603-2 can be fitted together with the plug-in connector. 
     Integrally formed in the longitudinal sides 8 of the collar 5 are pocket-like recesses 9 which are open towards the outside of the collar. Pushed or inserted into these recesses are further contact elements 10, the lateral surfaces 11 of which are thereby accessible to being contacted by contact elements of a mating plug which is not shown here. 
     These further contact elements 10 form rows 12 of contacts which are disposed parallel with the contact zone enclosed by the collar 5. 
     The contact elements 10 inserted into the recesses 9 are provided at their contact end 13, i.e. at the end which is to be connected with the corresponding mating plug in a contact making fashion, with lateral side sections 14 which are angled-over or turned-down so that the contact ends are held and guided in the recesses. For fixing the contact elements, their lateral side sections 14 have integrally formed retaining means or barb-like elements 15 which, when the contact ends are pushed into the recesses 9, engage in recess side walls 16 and ensure a secure seating of the contact elements 10. 
     As shown in FIG. 3, the recess means includes an outer portion 91 and an inner portion 92 with the outer portion 91 forming an opening which opens up into the outer wall of the collar 5. The inner portion 92 has lateral side channels 93, 94 located on either side of the outer portion 91. The contact element 10 has two lateral side sections 14 on either side of a raised central section 20. Thus the contact element 10 has a generally U-shaped cross-sectional configuration having a base part 101 and two legs 102, 103 extending from the base part 101. The inner portion 92 of the recess 9 has a first width 95 and the outer portion 91 of the recess 9 has a second width 96 which is less than the first width 95. The two lateral side sections 14 of the contact member 10 are disposed in the inner recess portion 92 and the raised central section 20 is disposed in the outer recess portion 91. The two lateral side sections 14 have a total third width 106 and the raised central section 20 has a fourth width 107 which is less than the third width 106. 
     The contact members 10 have a first part 108 disposed in the recess 9 and a second part 109 extending from the body generally parallel to the extending pin sections as shown in FIG. 1. 
     As shown in the embodiment of FIG. 2, the recesses have a first portion 97 and a second portion 98. The first portion 97 is formed in a generally planar indented wall 8 which is parallel to and spaced from the collar 5. The contact element includes a first section 110 disposed in the first portion 97 of the recess and a second section 111 disposed in the second portion 98 of the recess. A third section 112 of the contact element joins the first and second sections 110 and 111 at right angles as shown in FIG. 2.