Filtered electrical plug
This application is a continuation of application Ser. No. 684,229, filed Dec. 20, 1984, now abandoned. 
    
    
     RELATED APPLICATIONS 
     This application is related to U.S. patent application Ser. No. 683,846 filed on concurrent date by Raymond V. Pass and Patrick F. Yeager entitled &#34;Filtered Electrical Receptacles&#34; and assigned to the same assignee as the present invention. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to multiple pin connectors and more specifically to connectors having integral therewith bidirectional interference filters installed in mating plugs and sockets. 
     Multiple pin connectors of the type to which the present invention relates are used primarily in instruments, computers and the like that are enclosed in a case. The connectors have one member, the pin receptacle, mounted in the cabinet and contact is made with a cable through the other member of the connector, that is, the pin connector. In order to prevent electrical interference passing through the connector, the connector members are provided with tubular filter sleeves connected between each pin and ground to provide a low pass filter and thereby eliminate interference problems. 
     The filter connectors are difficult to produce and assemble and often do not insure good grounding of the tubular filter sleeves; a good strong interconnection between the cable braid and the connector housing is also an essential feature of a successful filter. 
     BRIEF DESCRIPTION OF THE PRESENT INVENTION 
     The present invention provides an easily assembled, economical multiple pin connector with interference filters extending between each pin and ground. The connector consists of an outer shell having tubular filter sleeve elements mounted therein, a pin housing, a ferrule for holding one end of the cable relative the connector, pin contacts seated in the pin housing and in contact inside of said tubular elements, an end member to position the pins near their contact ends and an outer guard. The pins are provided with spring fingers and lugs for engaging the edges of a shoulder in the pin housing so that the pins snap into place by insertion in the housing catching the edges of the shoulder between the spring fingers and the lugs. The pins are also positioned such to have a plurality of spring elements seated in each of the tubular members and in contact therewith. 
     To assemble the apparatus, the tubular elements are positioned each in a separate hollow cylindrical hole in a transverse wall in the outer shell and are soldered in place by use of a solder form and heat, the solder electrically connecting the tubular elements to shell. Each pin is connected to a separate lead of a cable and then inserted in the pin housing and locked in place. The pin housing is inserted into one end of the outer shield with the pins passing through the tubular elements and contacting them via spring fingers. The end pin support is inserted in the other end of the shell and the various elements are glued or otherwise secured in the outer shell as appropriate. Each of the solder plate, pin housing and end plate have keyways which cooperate with a key along the inner diameter of the shell to insure proper alignment of all elements. The cable braid, if the cable is braided, is applied over an end of the ferrule which is in contact with the shell. The assembly is enclosed within a rubberized plastic for support and color matching considerations. 
     The above assembly is simple and quick, the most complex part being the pins and those are of relatively simple construction. The outer shell is a die cast sleeve with an apertured transverse wall and the pin housing is a barrel of a plurality of elongated circular holes. An important feature is that the construction in large quantities readily lends itself to automated assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an expanded view showing all of the elements disassembled but positioned in the order of assembly: 
     FIG. 2 is a sectional view illustrating the assembly of the main components of the invention; 
     FIG. 3 is an exterior view of the assembled element without the rubber shield; and 
     FIG. 4 is an exterior view of the fully assembled structure. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now specifically to FIG. 1 of the accompanying drawings the major elements of the pin connector are illustrated in exploded view. The elements are contact pins 1 (only one illustrated), pin housing 3, solder disk 5, insulating hollow tubular members 7 having conductive coating on their inner and outer circumferential surfaces constituting the filter elements, outer shell 9 and an end member pin support referred to as the front insert 11. 
     The contact pin 1 constitutes a wire clamping end 13 having formable pairs of fingers 15 and 17 for crimping the stripped end 19 of a single wire 21 of a cable (not illustrated in FIG. 1). Fingers 17 clamp the insulation of the wire 21 whereby the pin 1 is secured to the wire in conventional fashion. The end 13 of the pin connector 1 connects with a split barrel section having diametrically opposed outwardly extending curved spring fingers 25 and 27, the outermost ends of the spring fingers 25 and 27 extending toward the end 13 of the pin. Located between the end 13 and the fingers 25 and 27 are lugs 29 (only one illustrated) extending out from the barrel 23 generally in line with the fingers 25 and 27. It is to be understood that the wire can be terminated to the contact pins by other means such as soldering or insulation displacement. 
     The pin 1 terminates in a contact region 31 comprising an elongated split cylinder terminating in a tapered alignment region 33. Extending between the region 31 and the barrel 23 are at least three outwardly bowed spring members 35 looking generally like a Japanese lantern. The entire pin is stamped and formed from a single piece of metal. 
     The pin 1 is adapted to be inserted in one of a plurality of circular passages or bores 37 in pin housing 3, there being one such passage 37 for each pin. The number of pins may vary from three to eight or more depending upon the use to which the connector is to be put. Referring specifically to FIG. 2 of the accompanying drawings, the interior of each bore 37 provides an inwardly directed shoulder 39 providing radial walls 41 and 43 spaced apart by the distance between spring fingers 25 and 27 and lugs 29 on the barrel 23. The diameter of the bore 37 to the left of shoulder 39 as viewed in FIG. 2 of the accompanying drawings, is of a diameter to maintain the fingers 25 and 27 in a somewhat compressed state. 
     Upon insertion of the pin 1 in a bore 37, the fingers 25 and 27 snap outward when pushed beyond the shoulder 39 and the shoulder is clamped between the fingers 25 and 27 and the studs 29, whereby the pin is locked in the bore. 
     Referrng now to FIGS. 1 and 2, each of the tubular filter members 7 is inserted in a different bore 45 in a transverse wall 47 in the shell 9. The tubular filter members 7 may be tubular capacitor members of the standard type or preferably be of the type such as those disclosed in U.S. Pat. No. Re. 29,258, the disclosure of which is incorporated herein. The tubular members 7 are longer than the length of the bores 45 and extend outwardly from the bores toward the right as illustrated in FIG. 2 and are positioned flush with the left surface of the wall 47. The tubular members 7 have a slightly smaller outside diameter than the diameter of the bores 45. The tubular members are located along the axis of the bores and a narrow space 53 is provided into which solder can flow to provide one plate of a capacitor. The solder plate 5 is provided with circular apertures 55 having the same geometric pattern as the bores 45 with the diameter of the circular apertures about equal to the outside diameters of the tubular members 7. The solder plate 5 is inserted into the interior of the shell 9 and slid over the ends of the tubular members extending outwardly from the wall 47. To assist in alignment of the solder plate 5 with the tubular members, and reference is made to FIG. 2, a key 57 extends radially inward from the circumferential interior wall of the shell 9. The plate 5 has a keyway or notch 59 located in its outer periphery such that when the key and keyway are aligned, the apertures 55 are aligned with the members 7. 
     With the tubular members 7 located in the shell 9, the solder plate 5 is slid into position over the ends of the tubular member 7 and is abutted against the right radial surface of the wall 47. The shell is now heated to cause the solder to melt and flow into the spaces 53 providing a good ground to the wall 47 for the plates of the filter sleeves formed in the spaces 53. 
     The front insert 11 having a plurality of bores 61 for receiving pins 1 may now be inserted into the left end of the shell as viewed in FIGS. 1 and 2. A key 63 in the shell and a keyway 65 in the insert are provided to align the bores 61 in the insert with the pins 1. The pin housing 3 is now inserted into the shell 9 with the pins passing through the tubular members and the bores 61 of the front insert 11, an annular skirt 67 extending axially from the wall 47 providing a stop for the pin housing. Alignment of the pin housing 3 and the tubular members is again achieved by a keyway 69 in the housing 3 and the key 57 in the shell. It should be noted that the structure is dimensioned such that the spring fingers 35 of each pin 1 are located inside of and in contact with the interior wall of a different tubular member 7 whereby to provide the other filter sleeve contact. The pin housing 3 is secured in place by forming a lip 73 at the rear end of shell 9. The front insert 11 is retained in place by an interference fit between its outer diameter and the inner diameter of the shell 9. It should be noted that the key 63 also provides the guide for mating with the connector receptacle of the aforesaid concurrently filed application. 
     To complete the structure reference is made to FIG. 3 of the drawings, a ferrule 69 is applied to the cable of which the wire 21 forms one lead; the cable being designated by reference number 71. The ferrule is applied over the cable before the structure contacts 1 are crimped to the individual leads. After properly crimping, the contacts 1 are inserted into the assigned bores 37 of pin housing 3. Assembly is then completed by forcing ferrule 69 over the rear of shell 9 and crimping ferrule 69 to the cable jacket. Cable ground is maintained by including either a cable braid or ground lead between ferrule 69 and shell 9. The ferrule is utilized to provide support for and relieve strain in the cable where it attaches to the connector. The assembly is normally covered with a rubberized plastic sleeve 77 for additional cable support and color matching. This member is preferably molded over the assembly in a separate operation. 
     It is seen that the present invention provides a connector that is easily assembled, economical, strong and provides the desired filtering action. 
     Other improvements, modifications and embodiments will become apparent to one of ordinary skill in the art upon review of this disclosure. Such improvements, modifications, and embodiments are considered to be within the scope of this invention as defined by the following claims: