ELECTRONICS BOX COAXIAL CONNECTION ASSEMBLY

Abstract: An electronics module coaxial connection assembly comprises a plurality of coaxial connectors (10) mounted in a die cast housing (4) that receives printed circuit boards (PCBs) (6, 8) therein. The PCBs are interconnected and mounted within the housing (4) by means of compliant pins that allow assembly in the axial direction (A). Contacts (51, 50) mounted along the edge (60) of the PCB (6) have fork-shaped contact arms (56) that plug onto the coaxial centre conductors (32) that project into the cavity area (34) of the housing. This enables connection of the PCB to the coaxial conductors by merely plugging the PCBs into the housing in the axial direction during assembly. Cost-effective manufacture of components and assembly is thus provided.

Description: ELECTRONICS BOX COAXIAL CONNECTION ASSEMBLY This invention relates to a connection assembly of an electronics box, the box having coaxial connectors. In applications such as satellite data reception systems, parabolic antennas capture and concentrate signals which are distributed to a plurality of receivers, for example to different apartments in a building. The signals received by the antenna are typically processed by an electronics module that separates the incoming signal into a plurality of signals. The separate signals may be carried by individual coaxial conductors, either for carrying a plurality of different signals, or for branching the signals to further electronic processing stations that distribute the signals to the various receivers. The electronics module thus requires a plurality of coaxial connections that interconnect the electronic circuitry therein to coaxial supply leads. Such an electronics box typically has an outer housing with a conductive shielding material, the housing may in fact be fully conductive such as die cast metal. It is known to provide a coaxial connector projecting from an edge of the housing, where the housing has a cylindrical projection extending therefrom that forms the outer conductor of the coaxial connector. A cylindrical dielectric part is placed within the tubular outer protrusion, and holds an inner conductor. The outer conductor is interconnected to ground circuit traces of the electronics modules which typically comprise printed circuit boards (PCBs) with components thereon. The coaxial connection typically has to be connected to the PCB. For many applications, it is important to produce a very cost-effective electronics module. A major cost of many electronics components is due to assembly of the components, in particular if manual operations are required, for example fitting together of the parts or soldering contacts or components. It is nevertheless necessary to achieve a reliable electronics box that has effective shielding against electro-magnetic or electro¬ static noise reception or emission. It is also important to ensure that a reliable electrical connection can be made to the electronics box. It would be desirable to simplify assembly operations, and in particular automate assembly operations as far as possible. It is an object of this invention to provide a coaxial connection assembly for an electronics box that is cost-effective and reliable. It is a further object of this invention to provide an electronics box connection assembly for interconnecting coaxial connectors to PCBs of the electronics module in a reliable and effective manner that is also cost-effective to assemble. Objects of this invention have been achieved by providing an electronics box connection assembly having a housing with conductive shielding or ground, and at least one coaxial connector having a mating face at the outside of the housing for connection to a complementary coaxial connector, and an inner end for connection to a circuit board of the electronics module, wherein the board has at least one terminal mounted proximate an edge of the board that is plugged onto the central conductor of the coaxial connector. The housing may comprise a base plate and side walls, where the coaxial connectors are mounted in the side walls and the base plate is substantially parallel to the circuit boards. The base plate would face an open end of the housing where the boards are received in a direction substantially orthogonal to the base plate. The terminals for interconnecting to the coaxial centre conductor, are arranged with respect to the coaxial central conductor such that during mounting of the board within the housing from the open end, the terminals are plugged to the centre conductor. A simple assembly operation is thus achieved by top mounting the board and simultaneously plugging onto the coaxial central conductors. The ground connection between the housing shielding and the circuit boards may be provided by having a plurality of grounding terminals, for example one on either side of the terminal for contacting the coaxial central conductor, that plug into the base of the housing. In the case of a metallic housing, the terminals may have compliant pin sections that plug into recesses in the housing base wall. The preferred embodiment of this invention will now be described with reference to the figures, whereby; Figure la is a cross-sectional top view of an electronics box housing; Figure lb is a cross-sectional view through line lb- lb of Figure la; Figure lc is a detailed cross-sectional view of a ground terminal on a PCB, grounded to the electronics box housing; Figure Id is a detailed top view of a housing stud for receiving a ground contact; Figure 2 is a cross-sectional side view of an electronics box with parts disassembled; Figure 3 is an isometric view of part of a coaxial connector; Figure 4 is a partial cross-sectional view through the electronics box; and Figure 5 is a partial top view of a PCB showing terminals for connection to a coaxial connector. Referring to Figures 1-3, an electronics module 2 comprises a housing 4, a first PCB 6 and a second PCB 8, and a plurality of coaxial connectors 10. The PCBs 6,8 have electric components 12 mounted thereon which are interconnected by conductive circuit traces on the boards. The housing 4 is of a conductive material, such as die cast aluminium alloy, however it would also be conceivable to provide an insulative housing having a conductive shielding layer thereon. The housing 4 has a base wall 14 and side walls 16,17 along a lateral edge of the base wall 14 and extending upwardly therefrom to an open end 18. A cover part (not shown) can be positioned against the upper edge 20 at the open end 18 for closing the components fully within the housing 4. The side walls 10 comprise tubular extensions 22 forming a cavity 24 for receiving a dielectric 26 therein. The tubular extension 22 comprises the outer conductor of the coaxial connector, where a plurality of coaxial connectors extend from different side walls 16,17. Within the dielectric 26 is a central conductor 28 that has a mating end 30 for coupling with a complementary connector and a connection end 32 that projects into the cavity area 34 formed by the side walls and base wall. The inner contacts 28 are revolution machined contacts in this embodiment, but could of course be formed by other manufacturing methods. Both the circuit boards 6 and 8 substantially fill the surface area within the enclosure 34 and are mounted in a stacked manner one upon the other. The boards are interconnected between each other by board interconnection terminals 36 that have compliant pin contact portions 38,40 at either end for resilient mounting in plated through holes 42,44 of the PCBs 6,8. The circuit board 6 could also be provided with positioning means such as holes 46 cooperable with centering means of the housing such as studs 48 for positioning of the board with respect thereto. Ground contact between the board 6 and the shielding of the housing 4 can be provided by a plurality of grounding terminals 51 that have a compliant pin section 52 for insertion in a plated through-hole 55 of the circuit board 6, and at the other end a fork-shaped pair of cantilever beam contact arms 56 for insertion into a corresponding recess 58 in the base wall. The recess 58 can be provided in a stud 59 projecting up from the base wall, as shown in Figures la-Id, and Figure 4. The stud may also provide a means for positioning the circuit board at a precise height above the base wall 14. The recess 58 may either plated with conductive shielding material or simply formed from the metal of the housing if it is die cast. The terminals can be manufactured in a simple manner by edge-stamping from sheet metal. Further terminals 50, which may be identical to the grounding terminals 51, are provided for connection to the central conductor connection portion 32 of the coaxial connectors 10. All terminals 36,50,51 may be formed by edge stamping from sheet metal into substantially planar shapes that are very cost-effective to manufacture. Both the grounding terminals and the central terminals for connection to the coaxial conductor, are positioned along edges 60 of the circuit board 6. The fork-shaped contact arms 56 form a slot 64 and receive the central conductor 32 therebetween in a resilient manner for electrical connection thereto. These contact arms can thus be used for contact with their outer edges 62 or slot 64, for contacting ground (in the recess 58) or the coaxial central conductor 32 respectively. The arcuate, outwardly-bowed outer edge surface 62 provides the outer contact surface, and also provides a guide means extending towards the free end 66 of the contact arms by the inwardly curved shape for guiding the contact in the recess 58. A tapered lead-in 68 is also provided for guiding the coaxial inner conductor into the contact slot 64. The base wall 14 could also be provided with ribs rather than recesses 58 for insertion in the grounding contact slot 64. Both the ground and coaxial terminals can be stamped from a single strip of sheet metal and supported by a base strip 70 that is sheared transversely at a central portion 72 between adjacent terminals. Very little scrap material is produced which lowers manufacturing costs of the contacts. An increase in scrap metal resulting from stamping procedures needs a more costly tooling for evacuation of metal, and the scrap also generates handling costs. It is therefore an advantageous feature to separate adjacent terminals by merely shearing them apart rather than separating them by taking out a piece of metal. Along the PCB, if adjacent terminals have base portions 70 that are too close together, the ground contacts can be orientated at a different angle to the coaxial contact that they flank thereby increasing the gap between adjacent contacts as shown in Figure 5 where the ground contacts 51 are turned at 90° to the centre contacts 50. The positioning at an angle of the ground contacts may also change the ground and shielding characteristics, the angle (between 0° and 90 * ) thus providing a means of tuning such characteristics. Boards 6 and 8 can thus be stacked together in the axial direction A, being interconnected by the contacts 36, and then plugged in the direction A into the housing cavity 34, such that the ground contacts 51 plug into the corresponding ground recesses 58, and the coaxial central contacts 50 plug onto the coaxial centre conductor connection portions 32. Advantageously therefore, due to the axial mounting of the boards to the housing, with simultaneous plugging to the coaxial conductors, rapid and automated assembly is enabled for a cost-effective solution. Furthermore, the simple edge-stamped circuit board terminals for connection to the coaxial inner conductors and ground are identical and therefore cost-effective to manufacture, but nevertheless ensure reliable contact.

Claims: CLAIMS 1. A connection assembly for an electronics box having a housing (4) and a printed circuit board (PCB) (6,8) mountable in the housing, the housing (4) comprising a base wall (14) and side walls (16,17) upstanding therefrom to form a cavity area (34) for receiving the PCB therein, the connection assembly comprising one or more coaxial connectors (10) extending through one or more of the sidewalls (16,17) for interconnecting the PCB (6,8) to a complementary coaxial connector external to the electronics box, characterized in that the connection assembly comprises one or more terminals (50) mounted proximate an edge (60) of the PCB (6) and pluggable to one or more coaxial centre conductors (28) of the one or more coaxial connectors (10) in a direction (A) of assembly of the PCB (6,8) into the housing (4). 2. The connection assembly of claim 1 wherein the coaxial centre conductor (28) comprises a connection end (32) projecting into the cavity area (34) below the terminal (50) for plugging connection therewith, the connection end (32) extending transversely to the assembly direction (A) . 3. The connection assembly of claim 2 wherein the terminal (50) comprises fork-shaped contact arms (56) that form a slot (64) for resiliently receiving the connection end (32) of the coaxial centre conductor (28) therein. 4. The connection assembly of claim 3 wherein the terminal is substantially planar and stamped from sheet metal, comprising a compliant pin section (52) for mounting in a conductive through-hole (54) of the PCB (6) . 5. The connection assembly of claim 3 or 4 wherein a base section of the terminal (50) intermediate the compliant pin section (52) and contact arms (56) forms part of a carrier strip interconnecting the terminals during manufacture, the outer edge (72) of the base section being sheared at the centre position between adjacent terminals during manufacture. 6. The connection assembly of any preceding claim wherein one or more grounding terminals (51) are mounted on the PCB (6) for interconnecting the PCB to the ground pole of the one or more coaxial connector(s) (10) , the grounding terminals pluggably connected to the housing (4) in the direction of assembly (A) . 7. The connection assembly of claim 6 wherein the grounding terminal is identical to the terminal (50) for connection to the coaxial centre conductor. 8. The connection assembly of claim 6 or 7 wherein a plurality of grounding terminals (51) are mounted along the edge (60) of the PCB (6) , where each terminal (50) for connection to the centre conductors is flanked on either side by a grounding terminal. 9. The connection assembly of claim 8 wherein the grounding terminals are mounted at an angle with respect to the terminal for connection to the coaxial centre conductor. 10. The connection assembly of any one of the preceding claims wherein board interconnection terminals (36) are provided for interconnecting two PCBs (6,8) stacked one upon the other in the direction (A) , the interconnection terminals (36) having compliant pins sections (38,40) on either end for mounting in conductive through-holes (42,44) of the PCBs (6,8), the interconnection terminals (36) being substantially planar.

Inventors: REYNOLDS CHARLES EDWARD, REYNOLDS, CHARLES, EDWARD
Applicants: REYNOLDS CHARLES EDWARD, WHITAKER CORP, REYNOLDS, CHARLES, EDWARD, THE WHITAKER CORPORATION
Application year: 1996
Main classification: H01R9
IPC codes: H01R9, H01R13, H02G15