Patent Publication Number: US-6659784-B1

Title: Connector with switching device

Description:
This application claims the benefit of the earlier filed International Application No. PCT/EP99/09418, International Filing Date, Dec. 2, 1999, which designated the United States of America, and which international application was published under PCT Article 21(2) in English as WO Publication No. WO 00/33425. 
    
    
     The subject of the present invention is a connector provided with a switching device of the kind described in the preamble portion of patent claim  1 . Such a connector is known for example from U.S. Pat. No. 5,741,146. 
     The invention can be used especially for switching between two aerial channels dedicated, for example, to mobile telephony. In this field, this type of connector is designed to allow switching, especially in a radio frequency range going from a few hundred MHz to a few GHz, from an internal aerial of a mobile telephone, used in portable mode, to an aerial external to the mobile telephone, for example that of a vehicle, to which external aerial the mobile telephone would be connected as required. The invention finds its justification more particularly in the mounting of such connectors on a printed circuit. 
     U.S. Pat. No. 4,633,048 describes a jack with a switch having a movable contact in a structure in which the contact is driven and separated from a fixed contact when the plug is inserted thereinto and the movable contact is brought into contact electrically with the plug. The housing of the jack has a longitudinal extension, which does not allow certain applications where a compact structure is obligatory. 
     U.S. Pat. No. 5,741,146 discloses a connector provided with a device for switching between two channels, this device including a first, fixed blade connected to a first channel and a second resilient switching blade exerting a contact pressure either on the first, fixed blade or on a pin of another connector, this pin being connected to a second channel and being inserted as required into the connector and wherein the second end of each blade is bent over in a same contact plane so that it is parallel to a contact surface on a printed circuit board and further comprising a hollow body inside which said device for switching is mounted, the second ends of the contact blades are supported by pins that give them a poor alignment with respect to a reference plane. The object of the invention is to propose a switch connector having a simple structure, compatible with the requirements of miniaturization, easy to mount on a printed-circuit board with an improved and more accurate alignment of the second ends of the blades in a predetermined contact plane of a printed circuit board and allowing effective and noise-free transmission within a radio frequency range. 
     A connector of this type consists of a hollow body inside which the aerial switching is carried out by means of two blades. The blades, when they are in electrical contact with each other, ensure connection between a transmitter/receiver and the internal aerial or, when they are separated (when introducing a coaxial plug of another connector into the hollow body), ensure connection between the transmitter/receiver and an external aerial. The advantage of the invention lies in the improvement and the simplification of these connections. 
     The coaxial pin of the other connector in most cases has a circular cylindrical shape. The contact thus formed between this pin and the resilient switching blade of the connector is a quasi-point contact in the case of a non-deformable material. In reality, the materials are not completely non-deformable, especially the switching blade which is resilient. Thus, a so-called quasi-point contact is in fact a contact in which the contact region is not a point but an area. However, in practice, given the dimensions of the components making the contact with respect to this contact area, it may be assumed that this area is sufficiently small to be regarded as a point. In fact, this contact area extends circularly at most over a quarter of the cross section of the circular cylindrical pin. This will constitute hereafter the definition of a point contact. 
     This type of connector has problems. With the requirements of miniaturization, the point contact area obtained is, for a pin less than 0.7 mm in diameter, less than 0.1 mm 2 . This type of contact is therefore not sufficiently effective to ensure that information is correctly transmitted or received. The effectiveness is in fact directly related to the quality of the electrical linkage produced. In addition, the contact resistance increases as the contact area decreases. A problem arises, especially when transmitting signals via the external aerial. This is because a signal emitted by this aerial may, in the case of mobile telephony, have a maximum peak power of up to eight watts. Thus, the transmission of such a signal through a point contact has the effect of causing the point of contact to heat up. This heat-up increases the rate of degradation of the contact, especially by oxidation. This causes accelerated reduction in the quality of the transmission of the signal from the transmitter to the external aerial. 
     Furthermore, another problem arises with regard to fastening such a connector to a printed circuit. The use of screws for doing this fastening is illusory,since the screws necessary would be too small to allow them to be easily handled by an operator. This therefore makes the fastening of these connectors to a printed circuit complicated, and therefore goes counter to the concern, expressed above, for simplicity. 
     A further object of the present invention is to remedy the problems mentioned by proposing a connector which includes a resilient switching blade allowing surface contact with a pin of another connector. The purpose of this surface contact is to improve the transmission qualities of a signal from a transmitter to an aerial or of a signal from, an aerial to a receiver, while at the same time satisfying the miniaturization requirements. Thus, with this surface contact, the overall contact area is increased. By increasing the overall contact area, the contact resistance is reduced. 
     A further object of the present invention is to provide an effective solution to these coplanarity problems by using a novel technique or technology for designing the present miniature coaxial switch or changeover-switch connector. This technique concerns the metallization of plastics, more particularly known by the name MID (Moulded Interconnection Device). 
     The invention thus aims to provide a miniature switch connector intended to be surface-mounted on a printed-circuit board, which includes a hollow plastic body comprising, at one of its ends, an opening intended to receive a connection plug which engages, during its insertion into this opening, with a resilient contact blade in order to separate the latter from a conductive surface, this contact blade and this conductive surface being connected to two conductive areas located at that end of the hollow body which is on the opposite side from the said opening. 
     According to the invention, this switch connector is characterized in that the said conductive surface consists of a metallized layer applied to part of the internal surface of the hollow plastic body. Further, the two conductive areas are coplanar and consist of two metallized layers applied to the external plane face of the hollow body which is on the opposite side from the said opening. 
     Given that the two metallized layers which act as output pads or terminals of the connector are applied to a plane face of the hollow body, the coplanarity of the two metallized surfaces is thus guaranteed, which in turn allows the connector to be surface-mounted extremely well. 
     In the invention, in practice two contact regions are made on the pin of the other connector. A first contact region defines a point contact, as described above, the second contact region being offset to the periphery of the pin. This has the effect of reducing the overall contact resistance due to connection between the resilient switching blade and the pin of the other connector. It will be seen that an elastic reaction, ensuring the first contact, is obtained by the elasticity of the resilient blade in its anchoring. The second contact is obtained by the elasticity of a side arm of this resilient blade. In order to ensure simple and effective fastening of this connector to a printed circuit, it is mounted using a surface mounting technique. Nevertheless, the elasticity of the arm allows firm contact to be made even if the anchoring is relatively fragile, especially when it results from surface mounting with a single soldered joint. 
     The invention therefore also relates to a connector provided with a device for switching between two channels, this device including a first, fixed blade connected to a first channel and a second, resilient switching blade exerting a contact pressure either on the first, fixed blade or on a pin of another connector, this pin being connected to a second channel and being inserted as required into the connector, characterized in that the pin comes into contact with the second blade at two points which are offset one with respect to the other on the periphery of the pin. 
     Preferably, a second contact of the second blade with this pin is obtained because this second blade includes a curved side arm which projects so as to be perpendicular to one surface of this second blade and a curvature of which is made along this projection. 
    
    
     The invention will be more clearly understood on reading the description which follows and on examining the figures which accompany it. They are presented only by way of indication and in no way restrict the invention. The figures show: 
     FIG.  1 : a sectional view of a connector according to the invention with a resilient switching blade exerting a contact pressure on a fixed blade; 
     FIG.  2 : the same connector according to the invention, with the resilient switching blade exerting a contact pressure on a pin of another connector; 
     FIG.  3 : a fixed blade of the connector according to the invention; 
     FIG.  4 : a resilient switching blade of the connector according to the invention; 
     FIG.  5 : a view of the base of the connector according to the invention; 
     FIG.  6 : a view of an insulating structure of the connector according to the invention; 
     FIG.  7 : a view of a plug for aligning and retaining the connector according to the invention; 
     FIG.  8 : a view of a conducting skirt of the connector according to the invention; and 
     FIG.  9 : an example of the application of the connector according to the invention in a mobile telephone; 
     FIG.  10 : a sectional view of another embodiment of a connector according to the present invention; 
     FIG.  11 : a sectional view of still another embodiment of a connector according to the invention; 
     FIG.  12 : a perspective view of the connector housing according to FIG. 11; 
     FIG.  13 : the switching blade of the connector according to FIG.  11 . 
    
    
     FIG. 1 shows a sectional view of a connector  1  according to the invention, provided with a fixed blade  2  and with a resilient switching blade  3 . When no other connector is connected to the connector  1 , the blade  3  is in contact, by pressure, with the fixed blade  2 . This contact is in fact produced by means of a side arm  4  which projects perpendicularly to one surface of the switching blade  3 . More specifically, the region of contact with the fixed blade  2  on the side arm  4  is located at a corner  5  of a free end  6  of the side arm  4 . The switching blade  3  is elongate and approximately plane. Three-quarters of the way up the switching blade, there is the arm  4 . At the start of manufacture, the arm  4 , cut together with the switching blade  3  from the same metal sheet and integral with the switching blade, is in the same plane as the switching blade. The side arm  4  then has a height oriented like the length of the switching blade  3 . The free end  6  of the arm is approximately parallel to this height. Near the upper corner  5 , the free end  6  is cut so as to be round. Furthermore, the plane of the switching arm  3  is then deformed in order to include a curvature of the free end  6 . The radius of curvature lies in a plane perpendicular to the length of the switching blade  3 . The side arm  4  is then bent over by folding or bending. The rounded corner  5  thus makes it possible to have an area of contact with the fixed blade  2  greater than the area of a point contact, as described above. The area of the region of contact between the side arm  4  and the fixed blade  2  does not need to be a contact having an area as large as the contact provided by the invention with a pin  7  of another connector. This is because, in a preferred example, the fixed blade  2  is connected to an internal aerial of a telephone. In this case, a maximum peak power of an electrical signal passing through this link is less than or equal to two watts. 
     In FIG. 2 showing a sectional view of the connector  1  according to the invention, the resilient switching blade  3  is in contact with a pin  7 , of another connector, this pin  7  in a preferred example being a circular cylindrical pin. This other connector is, for example, a connector  70  for a coaxial cable. The free end  6  at the end of the side arm  4  provides a contact at another point on the periphery of the circular cylindrical pin  7 . In the invention, the projection of the side arm  4 , perpendicular to one surface of the resilient switching blade  3 , is at a height of less than the diameter of the circular cylindrical pin  7 . In addition, a curvature is made along this projection. This curvature has the effect of bending the projection back towards the pin  7  so that the edge of the end  6  comes into contact with a generatrix of the pin  7 . Thus, when the circular cylindrical pin  7  is in contact with the switching blade  3 , the arm side  4  partly embraces this pin and two contacts are therefore obtained. An additional contact is obtained by means of the end  6  of the side arm  4  while a first, quasi-point contact is obtained conventionally by means of a boss on the resilient switching blade  3 . 
     In a variant, the projection of the side arm  4  is at least equal to the diameter of the circular cylindrical pin  7  and the side arm  4  at least partially surrounds the circular cylindrical pin  7 . 
     The side arm  4  is produced on the switching blade  3  in an intermediate position closer to a first end  8  of the resilient switching blade  3  than the mid-height of the switching blade  3 . This first end  8  is bent over so that it forms a sharp angle  9  and is oriented, in a preferred example, so as to be perpendicular to one face of the resilient switching blade  3 . This orientation of the end is in the opposite direction to the direction in which the side arm  4  projects. Thus, a sharp angle  9  of rounded shape is obtained between the first end  8  and the resilient switching blade  3 . This sharp angle  9  corresponds to that part of the switching blade  3  with which the first point contact is obtained. 
     The fixed blade  2  and the resilient switching blade  3  are inserted into a hollow body  10 . This hollow body  10  has an external shape with a symmetry of revolution about an axis  11 . Furthermore, this hollow body has a staircase-stepped profile with respect to the axis  11 . Thus, it has a first step  12  higher, with respect to the axis  11 , than a second step  13 . These two steps are separated, heightwise, by a riser  14 . The hollow body  10  also has two circular faces  15  and  16  perpendicular to the axis  11 . A recess  17  is made in the circular face  15 , the area of which is greater than that of the circular face  16 . This recess  17  has, in a preferred example, a profile which is rectangular in a cutting plane perpendicular to the axis  11 . In the recess  17 , the two blades  2  and  3  are inserted respectively into facing walls  18  and  19 . A hole  20  is made along the axis  11  on the same side as the circular face  16  and emerges in the recess  17 . 
     Thus, in order to obtain electrical contact between the resilient switching blade  3  and the circular cylindrical pin  7 , the latter is engaged in the hole  20  in the hollow body  10 . The diameter and the height of this hole  20  are designed so that the circular cylindrical pin  7  remains aligned, and therefore parallel to the axis  11 , whereas the pin moves the resilient switching blade  3  aside. It thus disconnects the resilient switching blade  3  from the fixed blade  2  at the moment of its introduction. A large electrical contact area, due the additional contact, is then provided between the resilient switching blade  3  and the circular cylindrical pin  7  thus introduced. 
     FIG. 3 shows a view of the fixed blade  2  of the connector  1  according to the invention. A first end  21  of the fixed blade  2  has an enlargement forming a contact pad  22 . This contact pad  22  is intended to make a contact on receiving the corner  5  of the side arm  4  during contacting between the resilient switching blade  3  and the fixed blade  2 . 
     A second end  23  of the fixed blade  2  is bent over so that this second end  23  is perpendicular to the fixed blade  2 . This second end  23  has a through-hole  24 . Likewise, in FIG. 4 showing the resilient switching blade  3  of the connector  1  according to the invention, a second end  25  of the resilient switching blade  3  is bent back in the same way as the second end  23 . This second end  25  has a through-hole  26  identical to the through-hole  24 . During the forming of the blades  2  and  3 , the parts  23  and  25  are prestressed so that they press against the circularface  15  of the insulating hollow body  10 . 
     FIG. 5 shows a view of the circularface of the connector  1  according to the invention. The circularface  15  of the connector  1  has two facing slots  27  and  28  into which the blades  2  and  4  respectively inserted. The two slots  27  and  28  are made in the walls  18  and  19  respectively and are wider then these walls  18  and  19 , the width being measured along an axis perpendicular to the axis  11  and parallel to the planes formed by on surface of the walls  18  and  19 . 
     Thus, after the blades  2  and  3  have inserted into the slots  27  and  28  respectively, their ends  23  and  25 , by virtue of their bent over shape and their prestress, but against the circular face  15  of the connector  1  and apply pressure thereto. Thus, contact areas of the ends  23  and  25 , intended to make contact with a printed circuit, are in the same contact plane is coincident with that of one face of the printed circuit board on which the connector  1  is placed. In addition, the ends  23  and  25  extend so as to come to the periphery of one edge of the circular face  15 . 
     This allows the connector  1  to be mounted on a printed circuit using a so-called SMC surface mounting technique. Such a surface mounting technique is a technique is which the printed circuit board is not drilled with holes. In such an SMC technique, the conducting pins of a component are not allowed to pass through the printed circuit board, these pins being soldered on the opposite face of the printed circuit board from its face in contact with the component. A mounting technique other than a surface mounting technique on a printed circuit board would require the printed circuit board to be drilled with holes so as to allow, for example, the ends  23  and  25 , which are not moved apart, of the blades  2  and  3  to pass through the printed circuit board. Or else, it would require holes so as to allow screws to pass through it, which screws would be fastened to the connector  1 . The latter solution poses construction problems. This is because the overall size of this connector is less than the size of a rectangular parallelepiped with a width and a thickness which are equal to or less than 2.5 mm and a length equal to or less than 7.5 mm. These values are given to an accuracy of 10%. Thus, for the circular face  15 , a diameter of 2.5 mm means a diameter of the through-holes  24  and  26  of less than 1.25 mm. In fact, the two through-holes  24  and  26  must have diameters such that the sum of them is less than the diameter of the circular face  15 , which means a maximum diameter of 1.25 mm for the through-holes  24  and  26 . In fact, the size of the through-holes is even less, since there must be sufficient space between the two through-holes  24  and  26  so as to avoid in particular any problem of parasitic coupling between the fixed blade  2  and the resilient switching blade  3 . For example, a space of five times the diameter of a through-hole  24  or  26  gives a hole diameter of less than 0.4 mm. Thus, 0.4 mm holes require 0.4 mm screws, which demands screw manufacturing methods that are too expensive compared with the manufacturing cost of a connector such as the connector  1 . Thus, one solution to this problem is to use a technique of surface mounting on a printed circuit. 
     However, the lack of relative strength of such an SMC mounting is compensated for by the second contact  6 , the elastic reaction of which is not entirely supported by the anchoring but by the facing slots  27  and  28 . 
     The through-holes  24  and  26  are situated in front of shafts  29  and  30  which are respectively formed out in the circular surface  15  of the hollow body  10 . A diameter of the shafts  29  and  30  is 50% greater than the diameter of the through-holes  24  and  26 . A soldering sphere, for example made of tin, is placed on the shafts  29  and  30 . This sphere has a diameter inferior to the diameter of the through-holes  24  and  26  so that it can be introduced into a shaft  29  or  30 . Thus, after having disposed the connector  1  on the surface of the printed circuit, the tin spheres are in contact with the printed circuit via the through-holes  24  and  26 . In order to melt the tin sphere, different processes of soldering components onto a printed circuit can be used, in particular an electrical soldering iron. The parts of the ends  23  and  25  which are situated at the periphery of the edge of the circular surface  15  are heated. In a variant, the fusion of the tin sphere could also be obtained by placing the printed circuit with the connector  1  in an furnace, but only if the fusion temperature of the tin is inferior to the fusion temperature of the connector  1 , during a time period sufficient to obtain the fusion of said sphere. In this case, so-called simple or double wave soldering techniques are used. It is an advantage of the shafts  29  and  30  that they permit a degassing during the fusion of the tin spheres. In fact, the fusion of the tin in the through-holes  24  and  26  provoke a filling of these latters. Thus, it must be possible to evacuate the gases resulting from the fusion of the tin. The shafts  29  and  30  permit this evacuation. Thus, the gas resulting from the fusion of the tin does not remain imprisoned in the melted tin after cooling, which makes it possible to obtain a homogeneous weld, that is in particular without air bubbles inside. 
     The hollow body  10  has an insulating structure  31  in which the recess  17  is made. This insulating structure  31  is inserted into a conducting skirt  32 , one profile of which, along an axis such as the axis  11 , corresponds to the profile described previously with respect to the hollow body  10 . 
     FIG. 6 shows the insulating structure  31  according to the invention. The blades  2  and  3  are inserted into the slots  27  and  28  in the recess  17  in order for them to be fastened to the insulating structure  31 . To do this, the fixed blade  2  and the resilient switching blade  3  are provided with an anchoring plates  37  and  38 , respectively. The anchoring lates  37  and  38  are made in an intermediate position. Projecting from these plates are two side arms  39  and  40  in the case of the fixed blade  2  and  41  and  42  in the case of the resilient switching blade  3 , respectively. Each side arm  39  to  42  has, at one end, an oblique fastening catch  43  to  46 , respectively. The distance between two ends of the two catches of a blade is greater than the width of the facing slots  27  and  28 . During insertion of the blades into the recess  17 , the oblique catches  43  to  46  penetrate rebates facing the facing slots  27  and  28 , thus ensuring retention of the blades  2  and  3 . In the case of the switching blade  3 , it is this retention which allows the elastic reaction of the second contact. 
     A groove is made in the insulating structure  31 , on the circular face  15  side, the groove being parallel to the slots  27  and  28  and being along an axis which is perpendicular to the axis  11  and passes through the latter. The groove is interrupted at the middle of it by the recess  17 . Thus, two grooves  33  and  34  are obtained, at the bottom of which holes  35  and  36  are made, respectively. 
     FIG. 7 shows a plug  47  which, in a preferred variant, makes it possible to align and retain the fixed blade  2  and the resilient switching blade  3 . Once this plug  47  has been inserted into the recess  17 , it presses each blade against the walls  18  and  19  of the recess  17 . The plug  47  has a shape complementary to the shape in a cutting plane perpendicular to the axis  11  of the recess  17  and has two side arms  48  and  49 . At the end of insertion of the plug  47  into the recess  17 , these side arms  48  and  49  butt against the bottom of the grooves  33  and  34 . The side arms  48  and  49  each have a preferably cylindrical stud  50  and  51  which are intended to be inserted into the holes  35  and  36 , respectively, so as to ensure that the plug  47  is put into position with respect to the insulating structure  31 . Furthermore, the top of the plug  47  has a pyramidal structure which ensures that the plug  47  is engaged easily in the recess  17 . 
     FIG. 8 shows a conducting skirt  32  of the connector  1  according to the invention, into which the insulating structure  31  is inserted. This conducting skirt  32  forms an external casing of the hollow body  10 . On the face  15  side, the metal skirt  52  has two shoulders  53  and  54  projecting parallel to the axis  11 . The tops of the free ends of these two shoulders  53  and  54  lie in the same plane  55 . This plane, when fastening the connector  1  to the printed circuit board, is coincident with that face of the printed circuit board on which the connector  1  is fitted. Thus, when soldering the ends  23  and  25  of the connector  1  to the conducting tracks on the printed circuit board, the shoulders  53  and  54  are themselves also soldered to a conducting track on the printed circuit board. In a preferred example, this track is connected to an earth reference potential, generally zero, thus ensuring that the conducting skirt  32  is at a zero potential with respect to potentials that may be found on the printed circuit. 
     When connection is made between the connector  1  and another connector connected to a coaxial cable, the conducting skirt  32  ensures electrical continuity of the screen of this coaxial cable to the reference potential on the printed circuit board. This connection between the conducting skirt  32  and the screen of the other coaxial cable is provided by a circular shell  56  (FIG. 2) of the coaxial connector  70 , surrounding the circular cylindrical pin  7 , in which shell the first step  12  is engaged. Once the circular shell  56  has been connected, it butts against the riser  14  of the hollow body  10  and the connector  1  can therefore provide electrical transmission between the printed circuit and an aerial connected to the coaxial cable. 
     FIG. 9 shows an example of the use of the connector  1  according to the invention. In a preferred example, the connector  1  is placed in a mobile telephone  57 . An internal aerial  58  of the mobile telephone  57  is connected via the second end  23  to the fixed blade  2 . The second end  25  of the resilient switching blade  3  is connected to a transmitter/receiver circuit  59  in the mobile telephone  57 . In this example, the mobile telephone  57  is used normally, that is to say the internal aerial  58  is used for transmitting and receiving information. A user having a vehicle  60  on the outside of which an external aerial  61  is fixed, thus has the possibility of connecting this external aerial  61  to the mobile telephone  57 . To do this, one end of the external aerial  61  has a coaxial cable  62  provided with a coaxial connector  63 . This coaxial connector  63 , similar to the coaxial connector  70 , is inserted into the connector  1  of the mobile telephone  57 , thus switching from the internal aerial  58  to the external aerial  61 . Thus the mobile telephone  57  uses an aerial  61  allowing it to transmit at a higher power than if the internal aerial  58  were used. 
     In a preferred example, the fixed blade  2  and the resilient switching blade  3  are obtained by moulding and are made of bronze. The insulating structure  31 , preferably made of polyvinyl chloride, is obtained by moulding, as is the conducting skirt  32 , which is made of iron. 
     FIG. 10 is a perspective view in axial section of a switch connector according to the invention. 
     The miniature switch connector illustrated in FIG. 10 is intended to be surface-mounted on a printed-circuit board, for example of a mobile telephone. 
     The connector has a hollow body  100  of cylindrical shape made of plastic, such as polyimide. This body is preferably moulded, which technique allows precise and reproducible manufacturing tolerances to be guaranteed. 
     The hollow body  100  comprises, at one of its ends, an opening  200  intended to receive a connection plug  300  which engages, during its insertion into this opening  2 , with a resilient contact blade  400  in order to separate the latter from a conductive surface  500 . This contact blade  400  and this conductive surface  500  are connected to two coplanar conductive areas  600 ,  700  located at the end of the hollow body on the opposite side from the opening  200 . 
     According to the invention, the conductive surface  500  consists here of a metallized layer applied to part of the internal surface  800  of the hollow plastic body  1 . Moreover, the two conductive areas  600 ,  700  consist of two metallized layers applied to the external plane face  900  of the hollow body  100  on the opposite side from the opening  200 . 
     As may be seen in FIG. 10, the contact blade  400  has an end  410  which is fixed to the internal surface  800  of the hollow body  100  close to that end of the latter which is on the opposite side from the opening  200 . 
     Moreover, the two metallized layers  600 ,  700  applied to the external plane face  900  each form a continuous metallized layer which passes round the internal edge of the hollow body, one of which is in contact with the end  110  of the contact blade  400  and the other of which is in contact with the metallized layer  500  applied to the internal surface  800  of the hollow body  100 . 
     Furthermore, the metallized layer  600 a which is in contact with the end  410  of the contact blade  400  extends below this end  410 . 
     Moreover, the conductive surface  500  applied to the internal surface  800  of the hollow body  100  forms a strip facing the resilient contact blade  400 . This strip extends over approximately the entire length of the internal surface  800 . 
     Preferably, the end  410  of the resilient contact blade  400  is soldered to the metallized layer  600   a  which extends below this end  410 . However, it could also be fixed to it by any other known means. 
     In addition, the external surface  112  of the hollow body  100  is covered with a metallized layer  113  forming a screen. 
     Furthermore, the external plane face  900  of the hollow body  100  comprises at least a third metallized layer  914  which extends at least on one side between the other two conductive areas  600  and  700  and which is connected to the metallized layer  113  forming the external screen of the hollow body  100  and making it possible to achieve electrical continuity and earthing of the printed circuit. 
     In the example illustrated, the three conductive areas or metallized layers  600 ,  700 ,  914  respectively are applied to the periphery of a flange  15  which projects outwards at the end of the hollow body  100 . 
     Moreover, as indicated in FIG. 1, the plane face  900  having the metallized layers  600 ,  700 ,  914  includes an opening  116  which may be closed off by a retaining piece  117 , the lateral surface  118  of which is in contact with the end  410  of the contact blade  400 . This arrangement makes it possible to consolidate the already strong fixing of the contact blade  400  to the internal surface of the hollow body. 
     This retaining piece can be provided in order to prevent disbanding or pull-out and to limit such stresses, during the lifetime of the connector, thus allowing the possible number of connections and disconnections when the connector or the external aerial is plugged in to be increased. 
     As already indicated in FIG. 1, that end of the contact blade which is adjacent to the opening  200  for inserting the connecting plug  300  has, on the one hand, a part bent over in a direction away from the metallized layer  500  applied to the internal surface  800  of the hollow body  100  and, on the other hand, a lateral finger  420  directed towards the metallized layer  500  and bearing on the latter. The shape of the bent-over part  419  is such that the insertion of the plug  300  into the opening  200  causes the contact blade to move in a direction away from the metallized layer  500  and causes the lateral finger  420  to separate from this layer  500 . 
     The diameter of the opening  200  and the shape of the end of the contact blade  400  are designed so that the plug  300  remains centred, whereas it moves the contact blade  400  aside in order to disconnect it from the conductive surface  500 . 
     When the plug  300  has been completely inserted into the hollow body  100 , a large contact area is established between this plug  300  and the contact blade  400 . 
     The metallized layers  500 ,  600 ,  600   a ,  700   113 ,  914  are preferably produced using the technique of metallizing plastics, known by the name MID. 
     The above metallized layers may also be coated with a layer of tin-lead alloy covered with a thin layer of gold or silver in order to improve the solderability. 
     Since the three metallized layers or conductive areas  600 ,  700 ,  914  lie strictly in the plane of the plane face  900  of the hollow body, it is very easy to solder them to the conductive areas on a printed-circuit board. 
     The surface-mounting is thus considerably simplified and the coplanarity problems usually encountered are eliminated. 
     In fact, it is completely possible to ensure the desired coplanarity tolerances since the base of the moulded hollow body corresponds to a perfectly defined reference plane (having precise and reproducible manufacturing tolerances) and since the layers  600 ,  700 ,  914  are directly metallized (with a thickness of about 15 to 20 microns) on this reference base. 
     Furthermore, such a connector makes it possible to ensure high-quality electrical connection either to the internal aerial when the resilient contact blade  400  and the conductive surface  500  are in contact with each other or to the external aerial when they are separated by the insertion of the coaxial plug into the hollow body. 
     Of course, the invention is not limited to the example that has just been described and many modifications may be made to it without departing from the scope of the invention. 
     FIG. 11 describes a further embodiment of a connector according to the present invention compared to the connector shown in FIG.  1 . This embodiment is much smaller in its longitudinal extension by fixing the rear end of the movable blade on a side extension  80  of the housing  90  by means of two tongues that are anchored in corresponding slits. This allows a perfect holding strength without the need of a plug  47  as shown in FIG.  1 . The longitudinal extension of the hollow body  90  can therefore be reduced essentially to the length of the male connector pin which leads to a reduction of the length of the connector housing of about 50%. 
     FIG. 12 shows a perspective view of the housing with the fixing slits  81  and  82  on the side extension at the rear end of the hollow body. 
     FIG. 13 shows the movable switching blade  3  with its fixing tongues  130 ,  131 . 
     It goes without saying that the idea of the embodiment as shown in FIG. 10 of the use of metallized surface can also be applied to this embodiment accordingly. That is, the fixed blade  2  can be replaced by a metallized surface and the switching blade  3  can be linked to a metallized area for further connecting it with other elements of a circuit. 
     The connector shown in FIG. 11 is therefore perfectly adapted for the intended use as a connector on mobile phones or the like.