Patent Publication Number: US-3874764-A

Title: Lead assembly

Description:
lllhUZh 071-19 United States Patent (1 1 Volinskie Apr. 1, I975 152] U.S. Cl. 339/97 R, 339/191 R [51] Int. Cl. H0lr 9/08, HOlr 19/04 [58] Field of Search 339/97-99.  
 [56] References Cited UNITED STATES PATENTS 3.016.512 H1961 Borchurd 339/176 M X 3.148.009 9/1964 Abramson.... 339/99 L 3.315.210 4/1967 Cull 339/176 M X 3.434.093 3/1969 Wcdckind 339/99 R X 3.474.394 Ill/1969 Hammcll ct a1 339/176 R 3.648.044 3/1972 Barnard et all. 339/97 R UX 1.673.542 6/1972 Di Stefano et a1. 339/176 M X 3.764.960 [0/1973 Hcimhrock 339/192 R X 3.767.841 10/1973 Anderson ct a1 339/97 C X OTHER PU BLICATIONS Horvath. Coaxial Wire Termination.&#34; 1MB Technical Disclosure Bulletin. Vol. 7. No. 11. page 989. April Dessauer et aL, Multiple Shielded-Wire Connector&#34; 1MB Technical Disclosure Bulletin. Vol. 8. No. 8. page 1057. Jan. 1966.  
 Horvath et al.. Ganged lnterconnector.&#34; 1MB Technical Disclosure Bulletin. Vol. 9. No. 3. page 242. August 1966.  
 Russia, Housing Assembly Connector-Splice 1MB Technical Disclosure Bulletin. Vol. 11, No. 8. page 669, Nov. 1968.  
 Primary Examiner-James T. McCall Assistant E.\&#39;aminerLawrence J. Staab Attorney. Agent. or Firm-AMP Incorporated [57] ABSTRACT The invention relates to an assembly for square posts such as are mounted on printed circuit boards and on back panels such as are used in telephone exchanges. More particularly. the invention includes a housing molded from insulating material and a pair of contacts within the housing having spring cantilever arms for receiving the square posts and a slotted plate for receiving the electrical wire carrying the signal to the board or back panel.  
  1 Claim, 5 Drawing Figures 389 LEAD ASSEMBLY BACKGROUND OF THE INVENTION Many applications use square posts projecting outwardly from the back of panels such as used in computer machines and in telephone exchanges. Square posts are also used in conjunction with printed circuit boards. A variety of ways of connecting wire to these square posts have been used in the past. For example. where the posts are spaced wide enough apart. wire wrapping techniques provides an acceptable termination.  
  Terminating coaxial cable: i.e.. cable having a center or sigmil-carrying wire. a shielding jacket and a ground wire for the shielding jacket. in miniature applications is quite a different problem. The difficulty lies in the fact that In o wires must be terminated in a extremely small space. An example of such dimensions is square posts 0.025 inches on a side and with a large number ofthem being positioned on a back panel in (l. I IN) inch centers.  
  Accordingly. it is an object of this invention to provide a device for terminating coaxial wire and a means for removably connecting such onto square posts.  
 BRIEF DESCRIPTION OF THI&#34;. DRAWINGS FIG. I shows a number of lead assemblies constructed in accordance with the present invention and stacked onto square posts such as are used in printed circuit boards;  
  FIG. 2 is an exploded view of one of the lead assemblies of FIG. I:  
  FIG. 3 is a top plan view of the base member of the lead assembly of FIG. 2;  
  FIG. 4 shows the manner of assembling the contacts in the base member and terminating a coaxial cable thereto; and  
  FIG. 5 is a top plan view of the assembled contact and cable without the housing.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. I illustrates the back side of a printed circuit board II) from which two sets of square posts I2 project. Each set of posts contain a signal post I2 .v (s standing for signal throughout this description) and a ground post 12;; (g standing for ground throughout this description). The top of each post is inwardly beveled to facilitate sliding lead assemblies I4 thereon. Extending from one end of each lead assembly 14 is a coaxial cable I6 which consists of a sgnal wire I8. a dielectric 20, a ground wire 22. a foil or metal sheath 23 surrounding dielectric and ground wire 22 and an outer insulating jacket 24 all as shown in FIG. 2.  
  With continuing reference to FIG. 2. an exploded view of lead assembly I4 is shown therein upsidcdown relative to FIG. I. Excluding cable I6. a lead assembly I4 consists of a base member or simply a base 26. a pair of contacts 28 .i&#39; and 28 g. and a cover member or simply cover 30.  
  Base 26 and cover 30 are molded from a glass-filled nylon or other insulating material.  
  A projection 32 extends upwardly (relatively speaking) at one end of the base. A lead assembly opening and cable channel 36 crosses through the projection from one end to the other and is adapted to admit the cable into the lead assembly such as seen in FIG. I. The  
 fall  
 mouth of the channel may be beveled as shown to facilitate the laying of the cable into the channel. A slight raise or boss 37 is positioned across the channel to provide. in cooperation with cover 30. a strain relief for cable I6.  
  Two parallel passageways or simply passages. 38 and 38 e extend through the lead assembly from top to bottom; i.e.. through both base and cover members. These passages may be beveled at the entrances to lacilitate sliding the lead assembly onto the aforementioned square posts for which the passages are dimensioned.  
  Two parallel cavities. .r and 40 e are provided within lead assembly I4 to house contacts 28 .i&#39; and 28 e. These cavities. one half of each in the base and the other half in the cover (not shown) are centered so that passages 38 .l&#39; and 38 e pass through the approximate center thereof. As the several Figures show. the cavities are orientated relative to each other so that an extension 42 .v of cavity 40 .v is generally normal and an extension 42 g of cavity 40 g is generally parallel to channel 36.  
  The openings 44 to each half of the cavities may be beveled to facilitate the placing of contacts 28.  
  Contacts 28. as seen in FIG. 2. consist of a square base 46. a pair of opposing. cantilever spring arms 48 converging toward each other and a plate containing a wire-receiving slot 52.  
  The contacts are preferably stamped and formed from a coplanar sheet of beryllium copper. or other suitable conductive material. The free ends 54 ofeach spring arm 48 may be rounded or beveled on the inside surface to facilitate pushing square posts I2 thereinbetween as the lead assembly is slid down onto the posts as shown in FIG. I.  
  Plate 50 is primarily the support and spring member for slot 52 which receives either signal wire I8 or ground wire 22. As one or the other wire is pushed down the slot. the sides comprising the plate are elastically deformed outwardly. This lateral movement which is slight. provides an important advantage in that the sides. in tending to narrow the width of the slot contributes to and enhances the electrical and mechanical properties of the connection.  
  The inside dimensions of base 46 is sized to just receive therethrough square posts I2. The arms 48 which extend from the base bear against the posts all along the arm&#39;s length. Electrical contact is enhanced by the converging arms being biased outwardly by the posts.  
  The placing of the contacts 28 in cavities 40 and the termination of cable 16 can be seen in FIGS. 4 and 5. Each contact is placed in a cavity in the only position possible; i.e.. with plate 50 being located in extension 42. The cavity location and orientation positively insures correct alignment and termination. The cable 16 is prepared by removing a short length of metal sheath 23. and outer insulating jacket 24. The prepared cable is then laid into channel 36 whose width is preferably sized to squeezingly receive the cable. Note in FIG. 5 that the sheath and jacket are on the cable through the channel.  
  After the cable is squeezed into channel 36. the ground wire 22 is pushed down into the slot 52 on contact 28 g. The signal wire [8 and its surrounding dielectric 20 is pushed down into slot 52 on contact 28 s. The sides of the slot on contact 28 g yield only enough that some of the metal is removed from the ground wire so that a good electrical contact is achieved. The slot in contact 28 is preferably dimensioned so that its sides cut through dielectric 20 and slightly into the signal wire to remove any oxide or dirt thereon and to achieve good contact. As noted above. the tendency of the sides of plates 50 to return to the normal non-stressed position acts to maintain good electrical contact and to provide a good mechanical grip. The drawing in FIG. 5 illustrates the termination of cable lb clearly. The drawing further shows how it is now possible to arrange the novel contacts closely together without creating possible electrical shortcircuiting.  
  After cable I6 is terminated in the manner described above. cover 30 is placed on top base 26 and fixed thereon by gluing. fusing. ultrasonically welded or other like means.  
  The boss 37. in cooperation with cover 30 when it is placed on the base. squeezes cable 16 and thusly provides a strain relief to protect the slotted termination of wires 18 and 22.  
  Although lead assembly 14 containing terminated cable It: is preferably placed on posts 12 upside-down relative to the description given herein. such positioning is not critical: i.e.. the assembly can be placed on the posts either upside-down or right-side up.  
  The lead assembly l4. as assembled and contained terminated cable I6. is slid onto square posts 12 so that post l2 .r passes through passageway 38 s. and contact 28 .r positioned in cavity 40 .s&#39; and post 12 g passes through passageway 38 g and contact 28 g positioned in cavity 40 g. A stable electrical circuit is now established between cable 16 and the printed circuit board or other device to which the posts are appended. Further. because of the obvious low profile which can be built into lead assembly l4. it is apparent that a number of such assemblies incorporating the novel features of the present invention can be stacked on one set of posts. Further. removal thereof is simple and can be done with the minimum amount of disturbance to adjacent lead assemblies.  
  The foregoing detailed description has been given for clearness of understamling only. and no unnecessary limitations should be understood therefrom. as some (il l modifications will be obvious to those skilled in the art.  
 What is claimed is:  
  l. A lead assembly for terminating the signal and ground wires in a coaxial or other like cable and for being slidingly positioned on a set of posts or the like. which comprises:  
 a. a rectangular base member having a longitudinal axis parallel to the major dimension of said base member. the top surface having an upwardly extending projection positioned across the width thereof at one end. said projection being bisected by a cable-receiving channel extending in the same general direction as the base member&#39;s longitudinal axis. a first cavity in the top surface located adjacent the projection and having an extension thereof positioned parallel to the base members longitudinal axis. and the second cavity in the top surface located remotely from the projection and having an extension positioned normal to the base member&#39;s longitudinal axis. said base member further having a pair of passageways extending from the bottom surface into the cavities:  
 b. a pair of contacts each consisting of a base with a pair of opposing spring arms extending therefrom, and a plate extending from the base in the same direction as the arms. each plate having at its free end a slot extending inwardly towards the base, said slot adapted to receive and electrically terminate one of the wires therein. each contact being positioned in a cavity so that the plate is received in the cavity extension thereby aligning the plate in the first cavity parallel to the longitudinal axis and the plate in the second cavity normal to the longitudinal axis thereby facilitating the terminating of the wires coming into the assembly through the channel; and  
 c. a cover member for placing over the cavities. said cover member having a pair of passageways therethrough in registration with the passageways in the base member to permit the assembly to be slidingly placed on a pair of posts which would then extend through the passageways and the opposing arms on the contacts.