Abstract:
The present invention provides a DIN jack including a dielectric shroud defining a closed entry lead-in that helps prevent damage caused by a bent or misaligned signal pin of a mating DIN plug without adversely affecting the performance of the DIN connector. The present invention also provides a board lock feature that may be used to hold a DIN jack securely to a circuit board during the manufacturing process.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/548,887, filed on Oct. 19, 2011, the disclosure of which is incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to electrical connectors. 
     BACKGROUND 
     Electrical connectors designed to interface in compliance with standards established by the Deutsches Institut fur Normung, a German standards organization, are referred to as DIN connectors.  FIG. 1  shows a standard DIN 1.0/2.3 connector  100 . The DIN connector  100  includes a DIN plug  102  with a signal pin  104  and a DIN jack  106  with a mating socket contact  108  axially aligned with the signal pin. Signal pin  104  and socket contact  108  are disposed within respective hollow, cylindrical shields  110 ,  112  that mate telescopically. Problems have been noted when this type of connector is miniaturized for use in a large array of connectors. For example, if the signal pin of a DIN plug is bent or misaligned even a small amount (e.g., more than 0.006″), it can brush by or butt against and damage the DIN jack with resulting signal loss and reliability problems. 
     SUMMARY 
     Embodiments of a first aspect of the present invention provide a jack (e.g., a DIN jack or other jack) including a tubular socket disposed coaxially within a hollow cylindrical shield and a closed entry lead-in that helps prevent damage to the socket caused by a bent or misaligned signal pin without adversely affecting the impedance of the connector. 
     In some embodiments of the jack, the lead-in is defined at the distal end of a shroud formed of a dielectric material. The shroud has a tubular shroud portion with proximal and distal ends disposed coaxially around the socket and is radially spaced from both the socket and the shield. In some embodiments, one or more openings are formed laterally through the shroud. 
     In some embodiments of the jack, the shroud includes a rim extending radially inward from the distal end of tubular shroud portion and defining a frustoconical lead-in coaxially aligned with the socket. 
     In some embodiments of the jack, the proximal end of the tubular shroud portion is coupled with the cylindrical shield or some other part of the connector body. 
     In some embodiments of the jack, the shroud includes an annular base extending radially outward from the proximal end of the hollow tubular shroud body and coupled with the connector body. 
     In some embodiments of the jack, an annular groove is formed along an inner surface of the cylindrical shield and the annular base of the shroud is received within the annular groove. 
     In some embodiments of the jack, at least some of the openings in the shroud are longitudinally spaced along a length of the tubular shroud portion, and/or annularly spaced about a circumference of the tubular shroud body. 
     In some embodiments of the jack, the openings are arranged in a plurality of longitudinal rows equiangularly spaced about a circumference of the tubular shroud body. 
     In some embodiments of the jack, the one or more openings are configured to modify a dielectric constant of the shroud to support 75Ω transmission of high-speed digital or RF signals. 
     In some embodiments, the frustoconical lead-in has a proximal opening with a diameter no more than 0.003″ larger than the inner diameter of the tubular socket and a distal opening larger than the inner diameter of the tubular socket. 
     In some embodiments, the shroud is formed of a liquid crystal polymer. 
     In some embodiments, one or more board locks protrude from the connector body and include at least one outwardly biased resilient finger with a rearward-facing shoulder configured to engage a bottom surface of a printed circuit board when the board lock is inserted through a hole in the printed circuit board. 
     In some embodiments, a pair of board locks are arranged in diagonally opposed relation relative to a longitudinal axis of the jack, alone or in combination with one or more mounting pins or posts. 
     Embodiments of a second aspect of the present invention provide a DIN connector having a jack with a shroud as described above and a mating DIN plug having a second connector body with a second hollow cylindrical shield configured to be received in the space between the shroud and the first hollow cylindrical shield and to make electrical contact with the first shield; and a second contact having a pin disposed coaxially within the second hollow cylindrical shield and being configured to be received within and make electrical contact with the tubular socket when the plug is inserted into the jack. 
     Other aspects of the present invention provide a connector jack with a shroud as described above, and connectors utilizing such connector jacks. 
     The above and other aspects and embodiments are described below with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers indicate identical or functionally similar elements. 
         FIG. 1  is a sectional side view of a prior art DIN connector showing a DIN plug partially mated with a DIN jack. 
         FIG. 2  is a perspective view of a DIN jack according to an embodiment of the invention. 
         FIG. 3  is a sectional side view of the DIN jack shown in  FIG. 1  taken along line  2 - 2 . 
         FIG. 4  is a sectional side view of a shroud for use in a DIN jack according to an embodiment of the invention. 
         FIG. 5  is a bottom view of the DIN jack shown in  FIGS. 2 and 3 . 
         FIG. 6  is a plan view of a printed circuit board configured to mount the DIN jack shown in  FIGS. 2 ,  3  and  5 . 
         FIG. 7  is a sectional side view of a DIN 1.0/2.3 connector with a DIN jack according to an embodiment of the invention. 
         FIG. 8  is a sectional side view of a right angle DIN jack according to an embodiment of the invention for panel mounting on a printed circuit board. 
         FIG. 9  is a sectional side view of a DIN to BNC adapter utilizing a DIN jack according to an embodiment of the invention. 
         FIG. 10  is a sectional side view of a DIN jack for video applications according to an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     A DIN jack  206  according to an embodiment of the invention, shown in  FIGS. 2 ,  3  and  5 , includes a connector body  214 , a contact  208 , and a shroud  216  that helps prevent damage to the contact while maintaining RF signal return loss performance. In this embodiment, the connector body  214  is configured to allow the DIN jack to be edge mounted on a printed circuit board (PCB). 
     The connector body  214  is formed of an electrically conductive material (e.g., brass) and, as best seen in  FIG. 3 , includes a distal portion defining a hollow cylindrical shield  212  with an open distal end, a proximal portion defining a proximal face  218  and one or more downward-facing board mounting surfaces  220  perpendicular to the proximal face  218 , and a threaded portion  222  of hollow cylindrical configuration with external screw threads between the proximal and distal portions. A mounting nut  224  is preferably provided on the threaded portion  222  of the connector body for use in mounting the jack to a panel. 
     Referring still to  FIG. 3 , the cylindrical shield includes a first annular groove  226  formed about an outer circumference of the shield near the distal end, and a second annular groove  228  formed about an inner circumference of the shield near the proximal end. The board mounting surfaces  220  are preferably planar and oriented parallel to and in alignment with the central longitudinal axis  230  of the cylindrical shield to align the center of the shield with the edge of a PCB when the mounting surfaces  220  abut the top of the PCB. Referring to  FIGS. 3 and 5 , the board mounting surfaces  220  are defined along respective bottom edges of two parallel arms  232   a  and  232   b  oriented parallel to the longitudinal axis  230  of the connector and laterally spaced apart. Two posts  234  are shown extending downwardly from the bottom edge of each arm, and the planar mounting surfaces  220  are disposed between the posts  234 . 
     A board lock  236  extends downwardly from one of the two posts  234  on each arm. Preferably, the board locks  236  are located on alternate posts so that, when viewed from the bottom as shown in  FIG. 5 , the board locks  236  are arranged in diagonally opposed relation (e.g., longitudinally and laterally spaced from one another). Each board lock includes a plurality of outwardly biased fingers or tines  238  combining to form a generally frustoconical insert with upwardly facing shoulders  240  configured to abut a bottom of the PCB when the board lock is inserted through a hole in the PCB and the mounting surfaces  220  abut the top of the PCB. The board locks  236  can be formed of any conductive material with suitable elasticity, e.g., phosphor bronze per ASTM 8139. 
     In the embodiment shown, the posts  234  without board locks are also arranged in diagonally opposed relation. In an embodiment, a post without a board lock on one arm is longitudinally aligned with a board lock on the other arm. It has been found that this arrangement helps meet spatial requirements by facilitating proper positioning and alignment of the connector on the PCB and by securely holding the jack in place during the soldering process. 
     As best seen in  FIG. 3 , the contact includes a tubular socket  242  with an open distal end disposed coaxially within the hollow cylindrical shield  212 . The tubular socket  242  is of much smaller diameter than the shield  212 , so the socket and shield are separated by an annular gap. In an embodiment, the tubular socket  242  has an outer diameter of 0.03 inches and an inner diameter of 0.02 inches, and the hollow cylindrical shield  212  has an inner diameter of 0.11 inches. A solder tail  244 , preferably having the same outer diameter as the tubular socket  242 , extends longitudinally from the tubular socket  242  in a proximal direction to protrude slightly from the proximal face  218  of the housing between the parallel arms at the proximal end of the housing. The contact  208  can be formed of any suitable electrically conductive material, e.g., a copper alloy, and is held in place by a sleeve  246  formed of an insulating material, e.g., PTFE (Teflon), disposed within the connector body  214 . In the embodiment shown, a lower edge of the solder tail  244  is slightly below the plane defined by the mounting surfaces  220 . In a preferred embodiment, a central longitudinal axis  230  of the solder tail  244  is coplanar with the mounting surfaces  220 . 
     Referring now to  FIGS. 3 and 4 , the shroud  216  is formed of a dielectric material and includes a tubular shroud portion  248  with proximal and distal ends, and an annular base  250  extending radially outward from the proximal end of the tubular shroud portion  248 . An outer edge of the annular base  250  is received within the annular groove  228  formed along the inner circumference of the cylindrical shield. The tubular shroud portion  248  extends coaxially around the contact socket  208  within the annular gap between the socket and the shield and is held in radially spaced relation to the socket and the shield so as to define first and second radial gaps therebetween. In an embodiment, the first radial gap (between the shroud  216  and the socket contact  208 ) is 0.005-0.015 inches, or preferably 0.01 inches, and the second radial gap (between the shroud  216  and the shield  212 ) is 0.015-0.025 inches, or preferably 0.02 inches. 
     In the embodiment shown, the shroud  216  includes a rim  252  extending radially inward from the distal end of tubular shroud portion  248  and defining a frustoconical lead-in  254  coaxially aligned with the socket. In an embodiment, the diameter of the lead-in decreases from 0.036 inches to 0.022 inches in the proximal direction, and the included angle θ of the lead-in is 90 degrees. In the case of the foregoing embodiment, the shroud  216  allows the socket  242  to be used with pins that are axially misaligned as much as 0.018 inches more than a standard connector socket. The lead-in terminates proximally in a straight through-hole having a diameter equal to the proximal diameter of the frustoconical opening, preferably 0.022 inches, which is only slightly larger than the inner diameter of the tubular socket  242  (preferably 0.02 inches). By interposing the lead-in between the socket and a mating plug with pin contact, the shroud  216  helps eliminate damage caused by a misaligned pin contact butting against or sliding past the socket. 
     Referring specifically to  FIG. 4 , it can be seen that the tubular shroud portion  248  has a wall thickness and a plurality of openings  256  that are formed laterally (i.e., perpendicular to the longitudinal axis  230 ) through the thickness of the wall. The wall thickness and number, size and location of the openings  256  are selected to produce a desired characteristic impedance. In some embodiments, (as illustrated by the dimensions shown in  FIG. 4 ) the wall thickness of the tubular shroud portion  248  is about 0.01 inches (e.g., as shown in  FIG. 4  the outer diameter (od) is about 0.073 inches and the inner diameter (id) is about 0.053 inches; as also shown the length (L) of the tubular shroud portion is about 0.175 inches in some embodiments, in other embodiments the length is less than 0.5 inches). In some embodiments, the wall thickness of portion  248  ranges from 0.01 inches to 0.1 inches. In the embodiment shown, twelve circular openings  256  are formed through the shroud  216  in four longitudinal rows spaced equiangularly about the circumference of the shroud  216 . In a preferred embodiment, each row includes three circular holes of 0.031 inch diameter spaced 0.05 inch apart center-to-center. In a preferred embodiment, counterpart openings  256  in adjacent rows are longitudinally aligned. The shroud  216  can be formed of any dielectric material that meets the thermal and mechanical requirements of the application. In particular, the shroud material is preferably hard enough for the lead-in to guide a misaligned pin to the socket without breaking and for the tubular shroud portion to resist bending when a misaligned pin slides against it. In addition, the shroud material preferably supports 75Ω transmission of high-speed digital (e.g., up to 6 Gbps) and radio frequency (RF) signals while maintaining RF signal return performance better than −25 dB to 5 GHz. In an embodiment, the invention supports up to 6 GHz and performance requirements per SMPTE-424 3 Gbit/s 3G-SDI broadcast signaling. In a preferred embodiment, the shroud  216  is formed of a dielectric material having a heat deflection temperature greater than 260° C. (more preferably, 280° C.) and a compression strength of at least 15 lbs (measured perpendicular to the longitudinal axis of the tubular shroud portion). In an embodiment, the shroud  216  is formed of a polyethermide, such as Ultem 1000 (unfilled). In a preferred embodiment, the shroud  216  is formed of a liquid crystal polymer (LCP); and, more preferably, a glass-filled LCP, such as Zenite 6130LX BK010. 
       FIG. 6  shows an edge portion of a PCB  258  with two pairs of diagonally opposed mounting holes  260  and  262  to receive the board locks  236  and alignment posts  234 , respectively. The mounting holes are spaced from the edge  264  of the PCB so that the proximal face  218  of the connector body  214  abuts the edge of the PCB when the board locks  236  and posts  234  are inserted through the mounting holes. The PCB also includes a small longitudinal trough  266  extending proximally from the edge of the PCB to receive the solder tail  244  when the DIN jack is mounted on the edge of the PCB. In an embodiment, the mounting holes are plated through holes. In an embodiment, the PCB is 0.063 inches thick. In an embodiment, at least some, and preferably all, of the mounting holes are plated through-holes. 
     In use, DIN jack  206  can be edge-mounted on a PCB by aligning the board locks  236  and posts  234  on the connector body  214  with corresponding holes in the PCB and pressing the jack and the PCB towards one another. As the jack and the PCB are pressed together, the tines of the board locks  236  will be deflected radially inwardly by the walls of the through holes and will spring radially outward once free from the hole to cause the PCB to be sandwiched between the bottom edges of the connector body  214  and the upwardly facing shoulders of the board locks  236 . The spacing of the holes from the edge of the PCB also ensures that the proximal face  218  of the connector body  214  is closely adjacent to or in contact with the edge of the PCB, so that in combination with the board locks  236  and posts  234 , the jack is held firmly in place and unable to move excessively in any direction. Once properly positioned, the solder tail  244  is preferably disposed within the trough formed at the edge of the board, between the connector arms, accessible for soldering. The jack  206  is then soldered to the board. The board lock feature also improves the manufacturing process by securing the jack so that there is no need to fixture a single jack or an array of jacks to the PCB during wave or reflow soldering. The board locks  236  also reduce manufacturing time by increasing the efficiency of placement and holding the jack  206  securely to the circuit board while the PCB is handled and soldered. In an embodiment, the shroud is formed of a material with sufficient heat deflection temperature to avoid becoming misaligned during the soldering process. 
     It will be appreciated that the DIN jack  206  of the present invention can interface with a standard DIN plug  102  as shown in  FIG. 7 . The pin  104  of the DIN plug  102  is received within the tubular socket  242 , and the cylindrical shield  110  of the plug is received within the gap between the shroud  216  and the cylindrical shield  112  of the jack. 
     A right angle DIN jack  306  according to another embodiment of the invention, for panel mounting on a printed circuit board, is shown in  FIG. 8 . The DIN jack  300  includes a hollow cylindrical shield  212 , a tubular socket  242 , and a shroud  216  like the DIN jack  206  shown in  FIGS. 2-5 ; however, the connector body  314  and solder tail  344  are configured to facilitate panel mounting on a PCB. Specifically, the connector body  314  includes a cube-like proximal portion defining a single board mounting surface  320  laterally spaced from the central longitudinal axis  230  of the shield so that the jack interface (and the nut) is elevated from the surface of the PCB. In this embodiment, the solder tail  344  extends from the proximal face  318  of the connector body and bends  90  degrees downward towards to the PCB. A second insulator  368  holds the solder tail  344  in position between the board locks  236  and the posts  234 . This DIN jack can be surface mounted on a PCB having mounting holes like the ones shown in  FIG. 6 , but with the addition of a central plated through-hole for the solder tail. 
     In another embodiment of the present invention, shown in  FIG. 9 , a DIN to BNC adapter  406  is provided. The adapter  406  includes a hollow cylindrical shield  212 , a tubular socket  242 , and a shroud  216  like the DIN jack  206  shown in  FIGS. 2-5 ; however, proximal ends of the connector body  414  and the contact  408  are configured to define the shield  470  and socket  472  of a BNC jack. 
     In yet another embodiment, shown in  FIG. 10 , a DIN video jack  506  is provided. The DIN video jack  506  includes a hollow cylindrical shield  212 , a tubular socket  242 , and a shroud  216  like the DIN jack  206  shown in  FIGS. 2-4 ; however, proximal ends of the connector body  514  and the contact  508  are configured to interface with high definition video equipment  574 . 
     While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. For example, while the shroud is shown as an integral, one-piece unit, it will be appreciated that the shroud can be made-up of multiple pieces that are bonded, fused, or otherwise connected together to form an integral unit. Also, while certain adapters are shown for converting between DIN and other interfaces, it will be appreciated that other adapters can be made using the DIN jack of the present invention. For example, the DIN jack can be used in a DIN jack to BNC plug. Further, while specific sheath openings are disclosed herein, it will be appreciated that other shapes, sizes, and/or numbers of openings can be used. Also, the arrangement of the openings can be modified. For example, the number of longitudinal rows of openings may be greater or fewer than shown, and the openings in adjacent rows may be longitudinally aligned as shown, or staggered. It will also be appreciated that, although the invention has been described with reference to the DIN 1.0/2.3 interface, the present invention may be embodied in other types of jacks and connector interfaces used in high-speed digital and RF applications. Additionally, the board lock feature may be used on a jack, as shown, or a plug. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments.