Abstract:
A coaxial switching connector especially applicable for use in cell phones is provided with a phone connector and a cradle connector where the cradle connector is mounted in a support structure via a conically shaped coil spring that allows both radial and axial displacement of the connector for absorption of tolerances and mechanical solicitation between the cell phone and its cradle.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a coaxial connector assembly. 
     2. Summary of the Prior Art 
     A common application for coaxial connectors with a switching function is found in cellular phones. Cell phones comprise their own antennas, but when mounted on a support in an automobile for example, the cell phone connects to an antenna on the automobile. The connection of the cell phone to the automobile antenna requires a switch during plugging of the cell phone to the support. The antenna connector is typically a coaxial type of connector having an inner conductor concentrically surrounded by a ground conductor. 
     An example of a coaxial switching connector assembly is shown in European Patent Application 0 685 911-A1. The switch function is accomplished by provision of a spring loaded bush mounted concentrically around a coaxial centre pin conductor and biased against a conductor pad. Disconnection between the centre pin and conductor pad occurs during plugging of the complementary connector which depresses the concentric bush member. 
     One of the problems of the latter design and other coaxial connectors, is that they are not adapted to absorb relatively large tolerances in positioning of the mating parts. This is particularly important in applications such as cell phones, where in comparison to the connector size, the positioning of the cell phone in its support (cradle) may vary significantly. 
     Another problem arises from the frequent plugging and unplugging and the relatively large shocks and forces to which contacts are subject in applications such as cell phones. It would be desirable to provide a coaxial connector interface that supports high mechanical solicitation and a large number of connection cycles in a compact and cost-effective manner. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide a coaxial connector assembly that withstands a large number of plugging/unplugging cycles in a reliable manner. It would be advantageous to provide a coaxial connector assembly that can tolerate relatively large tolerances between mating parts. It would be advantageous to provide a coaxial connector assembly with switching function that can withstand many connection/disconnection cycles. It would be further advantageous to provide such connector assemblies in a cost-effective, compact and robust manner. 
     Objects of this invention have been achieved by providing the coaxial connector assembly according to claim  1 . In particular, objects are achieved by provision of a coaxial connector assembly comprising a first coaxial connector and a second coaxial connector pluggably matable therewith in an axial direction, each connector comprising a mating section having an inner contact surrounded by an outer contact and separated therefrom by a dielectric, the outer contact of one of the coaxial connectors having a tapered lead-in portion for guiding and locating the connector mating sections during plugging together, wherein at least one of the connectors comprises a spring resilient in a radial direction orthogonal to the axial direction, the spring positioned intermediate the mating section and a support for fixed attachment to a device such that the connector is resiliently floatable in the radial direction with respect to the device. The spring may further be resilient in the axial direction for axial resilient movement of the connector. 
     Advantageously therefore, large tolerances between mating parts are absorbed for reliable interconnection over many cycles, and lowering risk of damaging mating components. 
     Objects of this invention have been achieved by providing the coaxial connector assembly according to claim  12 . In particular, objects are achieved by provision of a coaxial connector assembly comprising a first coaxial connector and a second coaxial connector matable therewith in an axial direction, each connector comprising a mating section having an inner contact surrounded by an outer contact and separated therefrom by a dielectric, the first or second coaxial connectors having a tapered funnel shaped lead-in portion for guiding and locating the connector mating sections of the first and second coaxial connectors during plugging together, wherein the inner contact of the first coaxial connector has a pin shape and is resiliently movable in the axial direction. 
     A further advantageous feature is provision of the axially movable centre contact of the fixed connector that abuts the centre contact of the mobile connector. The latter enhances resistance to shocks and permits reliable connection for many plugging/unplugging cycles. Face to face abutment of centre contacts enables contacts to project only by small amounts from mating faces of the dielectric, thereby reducing the risk of bending or otherwise damaging the centre pin contacts. 
     Further advantageous aspects of the invention will be apparent from the following description, drawings or claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view through a coaxial connector assembly according to this invention in a position just prior to mating; 
     FIG. 2 is a view similar to that of FIG. 1 of the connector assembly in the fully mated position; 
     FIG. 3 is a side plan view of a fixed connector of the connector assembly; 
     FIG. 4 is a cross-sectional view through lines  4 — 4  of FIG. 3; 
     FIG. 5 is a view in the direction of arrow  5  of FIG. 4; 
     FIG. 6 is a detailed plan view of part of a printed circuit board on which the connector of FIGS. 3-5 is received; 
     FIG. 7 is an exploded cross-sectional view through a mobile connector of the connector assembly of FIGS. 1 and 2; and 
     FIG. 8 is a plan end view of part of the connector of FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, a coaxial connector assembly  2  comprises a first connector  4  mounted on a printed circuit board (PCB)  5  within a device such as a portable phone having an outer housing  6  for reception in a device such as a telephone cradle  8  within which a second connector  10  is mounted for mating with the first connector  4 . Hereinafter the first connector  4  will also be called the mobile device connector and the second connector  10  will also be called the fixed device connector. 
     Referring mainly to FIGS.  1 , 2 , 7  and  8 , the fixed device connector  10  comprises a mating section  12 , a mounting section  14 , and a connection section  16 . The connection section  16  comprises a tubular portion  18  having a passage  20  for receiving an inner conducting wire  22  surrounded by a dielectric  24  of a coaxial (e.g. antenna) cable  26 . The outer surface  28  of the tubular portion  18  is for receiving an outer conductor  30  of the cable  26  thereover. The outer conductor  30  is crimped to the tubular portion by provision of a metallic ring  32  provided therearound, which is plastically deformed during the crimping process. The latter ensures on the one hand good electrical contact between the outer conductor  30  and the connection section, and on the other hand serves as a strain relief for securely holding the cable  26  to the second connector  10 . As shown in FIG. 1, a rear portion  33  of the securing ring  32  crimps around the outer insulation of the cable  26 . The connection section  16  further comprises a conductive casing  34  integral with the tubular portion  18  and having an axially extending passage  36  orthogonal to the tubular portion and in communication with the inner conductor receiving cavity  20  thereof. The axial passage  36  is provided with an end cap  37  that closes a rear end of the passage once the cable is assembled to the second connector  10 . In particular, the open end of the passage  36  enables the cable inner conductor  22  to be soldered, for example to a connection portion  38  of an inner contact  40  of the connector. A dielectric cap  42  can be further provided for positioning over the inner contact connection portion  38  prior to mounting of the cover  37  in order to separate the inner contact  38  from the outer housing and cover  34 , 37  which perform the function of outer conductor. 
     The inner contact  40  is mounted within a dielectric  44  which further supports an outer contact  46  concentrically therearound and extending in an axial direction A. The outer contact  46  is electrically and mechanically connected to the connection section outer conductor  34  by means of deformable crimping tabs  48  of the connection section crimped around a shoulder  50  at a connection end of the outer contact  46 . The dielectric  44  is provided with a shoulder  52  sandwiched between shoulders of the outer conductor housing  34  and the outer contact  46  for secure attachment thereof. 
     The inner contact  40  is securely held to the dielectric  44  by means of retention barbs  54  provided therealong in an interference fit with the dielectric  44 . A mating end of the substantially cylindrically shaped inner contact  40  is provided with a recess  56 , in this embodiment conically shaped. The recess  56  forms a contact surface for receiving and locating a complementary pin contact  58  of the mobile device connector  4  in resilient axial abutment thereagainst. The mating end  57  of the inner contact  40  is slightly recessed with respect to a mating face  59  of the connector, although it is possible to vary the position of the dielectric mating face  59 ′ as best seen when comparing the slightly different embodiments of FIGS. 2 and 7. The latter provides additional protection to the inner contact, and particularly the contact surface  56 . 
     The outer contact  46  is provided with resilient cantilever beam contact arms  60  extending from the mating end  59 , their free ends  62  being resiliently inwardly (i.e. radially towards the inner contact  40 ) biasable. The free ends  62  are provided with contact protrusions  64  for resiliently contacting a concentric outer contact  66  of the mating mobile device connector  4 . The resilient cantilever beams  60  are formed by cutting axially extending slits out of the generally tubular shaped outer contact  46 . 
     The mounting section  14  comprises a spring member  68  fixed at one end  70  to the connector mating section  12 , and fixed at the other end  72  to a support member  74  securely attached to the device  8 , which for example could be the housing of a mobile phone receiving cradle. An axial abutment member  76  is securely attached to the connector mating section  12  proximate the connection end  75  to limit axial displacement of the connector beyond a mating side  78  of the fixed device  8 . The abutment member  76  engages a shoulder  79  of the support  8 . The spring member  68  is in this embodiment a coil spring having a substantially tapered or conical shape where a small diameter end is wound around and attached to the outer contact  46  at the mating section attachment end  70 , and the large diameter end is at the support attachment end  72  in abutment against the support ring  74 . The conical shape of the spring enables both axial movement in direction A and radial movement in a plane with a direction R orthogonal to the axial direction A. The connector abutment  76  is thus slidably mounted against the surface  79  of the device  8 . The axial biasing force of the spring  68  is slightly greater than the mating force upon full mating of the connectors  4 , 10 , such that the spring is generally only axially compressed once the connectors have been fully mated depending on tolerances. If tolerances between the coupled connectors are such that the spring is axially compressed, the abutment member  76  lifts off the support face  79  of the device  8 . The spring may also ac to absorb shacks on the fixed device connector  10 , for example if the mobile device housing  6  or other objects abut the connector such that it resiliently moves axially or radially, thereby reducing the risk of damage by such shocks. 
     As best seen in FIG. 2, the conically shaped coil spring  68  enables substantial radial movement of the fixed device connector  10  with respect to the fixed device  8  in order to absorb tolerances in the radial direction in positioning between the mating connectors  10 , 4 . A flexible bull film or membrane  80  may be provided attached to the outer contact  46  of the mating section  12  in order to cover the cavity  82  of the device  8  within the mating section  12  is received. The latter serves to prevent ingress of dust and the like into the device. 
     Referring mainly to FIGS. 1-5, the mobile device connector  4  comprises a dielectric housing  84  within which is axially slidably mounted the centre contact  58 , and mounted concentrically therearound is an outer contact  66 . The connector  4  has a mating section  86  and connection section  88 . The connection section  88  comprises a first contact leg  89  and a second contact leg  90  mounted within recesses  91 , 92  respectively at a PCB mounting end  83  of the dielectric  84 . The contact legs  89 , 90  have surface mount contact portions  93  for surface mount soldering on a PCB  94  for interconnection to electrical components of a mobile phone, for example. The second contact leg  90  comprises a resilient contact arm  96  having a contact protrusion  97  for engagement against a contact surface  98  of the first contact leg  89 . The contact arm  96  is prestressed when mounted in the dielectric  84  such that the contact surfaces  97 , 98  abut with a certain force for reliable electrical contact therebetween. The resilient contact arm  96  extends across and axially below a rounded connection end  99  of the centre pin contact  58 . When the pin contact  58  is depressed towards the PCB  5 , the contact arm  96  is thus depressed and electrical connection between the legs  89 , 90  is broken. When the connectors  10 , 4  are fully mated, abutment of the inner contacts  40 , 58  thus breaks contact between the contact legs  89 , 90  as shown in FIG.  2 . The latter switch function for example causes a cell phone antenna to be switched to the antenna of the fixed device  8  when the cell phone is mounted thereon. The resilient contact arm also provides the spring force for abutting the slidable inner contact  58  against the mating inner contact  40 , such that few components are needed to provide the switching and contact functions. The axial face-to-face abutment of the slidable inner contact  58  and inner contact  40  as shown in FIG. 2, enables the slidable contact end  85  to project only slightly beyond the mating face  87  of the dielectric  84 . The latter reduces the risk of damage to the contacts during plugging, or with respect to external objects. 
     The outer contact  66  is provided with a large conical lead-in section  94  for guiding the mating section  12  during plugging. The tapered or conical lead-in section  94  is quite substantial in order to absorb relatively large tolerances in radial positioning of the connectors  4 ,  10 . 
     The contacts legs  89 , 90 , which may be cost effectively manufactured from stamping and forming sheet metal, are provided with V-shaped retention members  100  that dig into opposed walls of a slot  102  in the mounting end  93  of the dielectric  84 . The contact legs can thus be securely attached and positioned with respect to the dielectric  84  by merely depressing the retention portions  100  into the slot  102 . The connector  4  maybe robustly supported on the PCB by the solder connection of the contact legs  93  in addition the solder connection of the outer contact  66  which is provided with opposed solder mount extensions  104  mountable against the PCB  5 . As shown in FIG. 6, the PCB  5  is provided with arcuate conductive traces  106  for solder connection to the outer contact solder mount extensions  104 . Due to the arcuate shape of the extensions  104 , which are substantially a continuation of the cylindrical shape of the outer contact  66 , a robust attachment to the PCB is provided, in addition to the possibility of providing a substantial solder area around the connector  4  that enhances the robustance of the solder connection. The solder connections also provide the electrical connections to the outer and inner contacts  66 , 58 .