DEVICE FOR THE SCREENED CONNECTION OF CABLES AND METHOD FOR CONNECTING A COAXIAL CABLE

Abstract: A device is described, for the screened connection of at least a screened cable (4), in particular a coaxial cable, comprising at least two conductors (4A, 4C) for carrying video and/or audio and/or data signals, said device comprising a body (2) to which a connection element (7) is associated, being in contact with said cable (4) and capable of movement with respect to said body (2), where fixing means (5, 6) are provided for locking said connection element (7) to said body (2). According to the invention, following a movement of said connection element (7) with respect to said body (2), in particular imparted through said fixing means (5, 6), said connection element (7) is capable of changing its own configuration with respect to said cable (4), in order to obtain a mechanical and/or electric coupling between said cable (4) and said connection element (7).

Description: DEVICE FOR THE SCREENED CONNECTION OF CABLES AND METHOD FOR CONNECTING A COAXIAL CABLE DESCRIPTION The present invention relates to a device for the screened connection of cables, in particular coaxial cables, and a method for connecting a coaxial cable. It is known that, at present, besides the common sockets for terrestrial television signals, usually of the so called IEC type, also the sockets for television signals from satellite, generally known as sockets of the F type, are coming more frequently in use; in this connection, it is known that the considerable advantages offered by digital television, both now and in a near future, will lead to a fast increased distribution of these signals in people's houses. The two cited types of sockets differ for their frequency operating range; in fact, while the IEC sockets are apt to supply analog signals in the frequency band ranging from 40 to 860 MHz, the sockets for satellite television signals operate typically from 40 to 2150 MHz, both with analog and digital signals. Modulations employed in digital television, i.e. QPSK (Quadrature Phase Shift Keying), QAM (Quadrature Amplitude Modulation) and OFDM (Orthogonal Frequency Division Multiplexing) imply the need for more care in sockets manufacturing. In particular, the screening and the impedance matching, which are already significant for analog signals, become essential when operating with digital signals, both from the satellite and by cable and terrestrial. A good screening is in fact necessary in order to avoid outer noise or interferences overlaps the digital signals, which have in general a lower level than analog signals. Moreover, an impedance mismatch, i.e. a high "return loss", intended as a ratio between the characteristic impedance of the coaxial cable normally used for distributing television signals and the impedance resulting from the cable distortion, will cause a malfunction of the digital signals receiver. Obviously, the above applies independently from the type of information contained in the digital signal, and therefore not only for television signals (video plus audio), but also for sole audio signals and data carrying signals, as it occurs typically in multimedia systems. It is also known that television signal sockets may be of different types, depending upon their assigned function; in particular: - mixing sockets, which output the signals coming from several coaxial cables; - derived sockets, which are installed along the line of a coaxial cable provided for distributing the signal to various sockets; - terminal sockets, wherein the coaxial cable is closed on the typical impedance of the user; - demixed sockets, wherein the input signals, pertaining to various frequency bands, are separated by appropriate and known circuits, for being conveyed to several output sockets, each one of them supplying signals comprised in a determined band, such as a first socket with signals up to 900 MHz and a second socket with signals from 900 to 2150 MHz. Television signal sockets according to the prior art, independently from their type and/or the fact of being provided for receiving analog or digital signals, are usually of the built-in type, i.e. inserted inside a walled-in box, fastened with screws through a suitable frame. One or more coaxial cables reach the box, through an appropriate canalization; in the instance of a terminal socket, the cables stop inside the socket, whereas in the other instances they exit the socket to convey the signals to other sockets. During the installation, each coaxial cable to be connected to the socket is extracted from the relevant walled-in box and "stripped", i.e. removing a few centimeters of the sheath protecting its ground plait and of the insulating material, or dielectric, protecting the central conductor. Then the cable is connected to the socket, usually by fastening the central conductor with a screw, and the ground plait with a screwed U-bolt; it should be noticed that the use of screws is necessary, according to the prior, for ensuring both the electric connection and the mechanical solidity of the cable-socket coupling. Finally, the socket is fastened in the box, to the above frame, with screws. The above operations for connecting the cable to the socket may cause electric problems, such as the poor screening of the connection of the central conductor, or the impedance mismatch due to a cable distortion or deformation, i.e. the coaxiality city loss, should the U-bolt be excessively tightened. The situation becomes further worse when the socket is inserted in the box after having executed the relevant connections. It should be noticed, in this respect, that the execution of the connections is usually a very uncomfortable operation for the installer, since the sockets are commonly located a few centimeters from the floor; consequently, in order to make the job easier, the installer has the tendency to extract from the canalization or tube more length of cable than that strictly required. However, at the time the socket is inserted in the box, and being the space available in the latter rather limited, the screened cable is usually subject to further deformation, due to its narrow radius bending and squeezing, thus increasing the impedance mismatch and causing a signal degradation often unacceptable. As it can imagined, the negative consequences of the above problems, being already significant in the instance of sockets provided for receiving analog signals, are considerably increased for the sockets provided for receiving digital signals. From documents IT-B-1.287.047 and IT-B-1.289.463 a signal socket for two coaxial cables is known, which comprises a socket body made from electric conductive material, wherein a housing is obtained, which is apt to receive a sliding element or carriage; the bottom wall of the above housing defines two hollow truncated-cone projections, each one of them having an axial passage with a diameter in the order of the diameter of the dielectric of a standard coaxial cable. According to the solution described in the above documents, in order to provide the screened connection, the end of each cable to be connected is inserted in the axial cavity of the relevant truncated-cone projection, from the tip end of the latter; in this way, the end portion of the dielectric can enter the axial cavity, whereas the sharp edge of the truncated- cone projection can penetrate between the dielectric and the cable plait, causing an enlargement of the plait itself, resting on the outer surface of the projection. At this point the cited carriage, which is provided with axial passages having a portion of truncated-cone section similar to the one of the cited projections, can be locked in its relevant housing, by tightening a screw; in this way, the pressure of the carriage on the projection, with interposed plait and outer sheath, causes a mechanical locking of the cable itself, and the contact between the plait and the socket body made from electric conductive material. However, also the solution described in the above documents has some drawbacks. A first drawback is due to the fact that the plait of the cable to be connected and its outer sheath have to be submitted to a mechanical deformation under effort, for matching to surfaces of the socket body; the installer has difficulties to control this operation, also considering the small size of the socket and its usual uncomfortable location, i.e. a few centimeters from the floor; in this connection, it should be considered that the installer has to maintain the cable under thrust, towards the inside of the socket, also during the locking phase of the carriage. It is also pointed out that some coaxial cables have a band, usually made from aluminium, arranged between the ground plait and the relevant dielectric; now, due to the small thickness of said band, some parts of it may penetrate the cavity of the projection, so affecting the connecting operations negatively. Additionally, the above cited solution has a poor flexibility, since it presumes the substantial correspondence of the diameter of the axial passage of the above truncated-cone projection with the diameter of the dielectric of the cable to be connected; therefore, in this frame, this solution does not appear capable of use for cables having different sections. Moreover, the mechanical fastening system described is subject to possible risks of the cable being extracted from the socket, should the cable be accidentally pulled off. Another drawback of the solution described in the above documents consists in the complicated and uncomfortable connection operations, in the instance of sockets provided for receiving two cables (dual sockets); considering, in fact, that the final connection is obtained locking a single carriage, the installer will have to face the problem of maintaining manually both cables in their correct connecting position, before locking the carriage itself. At the light of the above, a first aim of the present invention is to indicate a device for the screened connection of cables, in particular coaxial cables, which allows for realizing a mechanical and/or electric connection in a fast, comfortable and safe manner, without the use of U-bolts, and which minimizes the number of screwing operations, so as to ensure an efficient screening and avoid possible impedance mismatching risks. A further aim of the present invention is to provide a connection device of the cited type, wherein no substantial mechanical deformations are caused to the cable, during its mechanical and electric connection. A further aim of the present invention is to provide a connection device of the cited type, which can be indifferently used for cables provided for signals of the analog type and/or signals of the digital type. A further aim of the present invention is to provide a connection device of the cited type, which can be used for various types of cables, even having different sections. A further aim of the present invention is to provide a connection device of the cited type, wherein risks of uncoupling and disconnection, due to undesired cable pulls, are minimized. One or more of the above aims are attained, according to the present invention, by a device for screened connection of cables, in particular coaxial cables, and a method for connecting a coaxial cable, having the characterizing features described in the annexed claims, which form an integral part of the present description. Further aims, features and advantages of the present invention will become apparent from the following detailed description and the annexed drawings, which are supplied by way of non limiting example, wherein: - Fig. 1 shows a schematic front view of a first signals socket, in a first possible embodiment of the present invention; - Fig. 2 shows a longitudinal section of the signals socket represented in Fig. 1 ; - Fig. 3 shows an enlarged detail of Fig. 2; - Fig. 4 shows, though various views, a possible embodiment of a first element capable of movement of the socket represented in Figs. 1-3; - Fig. 5 shows, through various views, a possible embodiment of a second element capable of movement of the socket represented in Figs. 1-3; - Fig. 6 shows a schematic view of a second signals socket, in a second possible embodiment of the present invention; - Fig. 7 shows, through a section being similar to the section of Fig. 3, a possible variant of use of the present invention. Referring to Fig. 1, reference 1 indicates a signal socket as a whole, according to the teaching of the present invention; in the specific instance, the socket 1 is of the screened and modular built-in type, i.e. consisting of a plurality of elements coupled to each other, which are provided for being housed in a suitable built-in box, of the known type. The socket 1 comprises a main body, or screening body, indicated with 2, and a generic coaxial connector, indicated as a whole with 3, which is provided for receiving a corresponding coaxial plug (not represented) for the picking up of signals by a user device (such as a television receiver, a digital signals satellite receiver, a multimedia apparatus, etc.); the coaxial connector 3 consists, in a known way, of a central conductor 3A and a perimetrical conductor 3B, with an appropriate insulating material 3C in between. Reference 4 indicates a screened cable, of the coaxial type, being coupled with the body 2, where it is electrically connected to the coaxial connector 3. In Fig. 2, the socket 1 is represented with a longitudinal section; for clarity's sake, Figs. 3, 4 5 represent some elements of the socket 1 , which are oversized compared to Fig. 2 and shown according to different views. At one end of the body 2 of the socket 1 , which is made from electric conducting material, such as aluminium or die-cast zama (Zn+Al+Mg alloy), a housing AA is defined, apt for receiving a component 5. The component 5, further identified as carriage, is capable of sliding within the housing AA and is detailed in Fig. 4; this carriage 5 can be manufactured either from electric conducting material, such as die-cast zama or aluminium, or non conductive material, such as plastic material. In the example illustrated in Fig. 4, the carriage 5 consists substantially of two tubular portions of different length and diameter, which are overlapped and joined to each other. A threaded cavity 5 A is defined in the longer portion indicated with 5', which is apt for receiving a fastening screw, indicated with 6 in Figs. 2 and 3, whose function will be cleared later; in the shorter tubular portion, indicated with 5", a main cavity is defined, indicated with 5B in Fig. 4; this main cavity 5B is apt for receiving the cable 4 and a connecting element, later identified as a gripping basket, which is shown in detail in Fig. 5. The screw 6 of Figs. 2 and 3 is apt to be inserted in a passage 2A obtained in the main body 2; the passage 2 A results in being aligned with the above said threaded cavity 5 A of the carriage 5, when the latter is inserted in the housing AA, and departs from the end of the body 2 opposite to the end wherein the housing AA is defined; as illustrated in Figs. 2 and 3, the screw 6 provides for the mechanical connection between the screening body 2 and the carriage 5. In Fig. 5 the gripping basket 7 is represented according to various views. Said basket 7 is made from mechanically elastic and electric conductive material, such as phosphorous bronze or beryllium copper, for example with a thickness of 0.4 mm. The basket 7 comprises a tubular portion 7A, wherefrom a first set of six elastic wings indicated with 7B is departing; the basket 7 also has a second set of six elastic wings indicated with 7C, which are longer than the previous ones and alternated with them; their function will be described in the following. The wings 7B are mostly straight and have their free end 7B * bent towards the inside of the basket 7; the longer wings 7C have a first bending IC towards the inside of the basket 7, just a little over the zone where the ends 7B' of the wings 7B are located, and a second bending 7C" towards the outside of the basket itself. Therefore, as it can be seen, the shape of the wings 7C forms a sort of a funnel or shrinkage, of the axial passage being inside the basket 7. The basket 7 has some hooking projections 7D on its tubular portion 7 A; these projections 7D are used for mechanically coupling or securing the basket 7 within the main cavity 5B of the carriage 5; to this purpose, the carriage 5 has appropriate cavities, one of which is visible in 5C on the right part of Fig. 4, apt for receiving and retaining the above projections 7D of the basket 7. In particular, as it can be seen in Fig. 3, in a first possible way of use of the connecting device according to the invention, the internal passage of the basket 7 is apt for receiving, from the side of the tubular portion 7A, the coaxial cable 4 being appropriately prepared as further described; the cable 4 is inserted in the basket 7 to have a portion of the ground plait 4A of the same cable extending on the usual dielectric material, indicated with 4B (eventually, the cable 4 can be of the type which provides for an aluminium band between the plait 4 A and dielectric 4B). Following this insertion, the end portion of the cable 4 (i.e. the portion bearing the end of the dielectric material 4B, the end of the plait 4A and the end of the central conductor of the cable, indicated with 4C in Fig. 3) will project from the end of the basket 7 being opposite to the tubular portion 7A, i.e. the end defined by the free ends of the longer wings 7C. Moreover, as it can be seen from Fig. 3, following the above insertion, the shorter wings 7B of the basket 7 provide for flexibly engaging themselves with the outer sheath of the cable 4, indicated with 4D, whereas the longer wings 7C, in line with their bending 7C", provide for flexibly pressing on the dielectric 4B of the cable, with the interposed the plait 4A and the likely aluminium band. In Figs. 2 and 3, reference 8 indicates a conductor element, provided for conveying the signal from the central conductor 4C of the cable 4 to the central conductor 3A of the connector 3; reference 9 indicates an electric insulation, arranged around the conductor element 8. One end of the conductor element 8 defines, in a known way, a contact apt for receiving and flexibly retaining the end of the central conductor 4C of the cable 4; this contact may be, for example, of the fast coupling spring type, indicated with 8 A in Fig. 3; in the given example, the conductor element 8 and the contact 8A are manufactured in a single piece, but they may also be manufactured in separate parts joined together, for example by welding. On the contrary, the other end of the conductor element 8 is connected to a conducting path 8B, carried by an insulating support 10 visible in Fig. 2, which is located in the body 2 and consists for example of a printed circuit; the conducting path 8B of the insulating support 10 is connected in turn to the central conductor 3 A of the connector 3, in particular by welding. It will be appreciated that electric coupling or uncoupling components may also be eventually mounted on the insulating support 10, should the socket according to the invention be a mixed or de-mixed socket, respectively. As said above, the connection between the central conductor 4C of the cable 4 and the conductor element 8 can be of the fast coupling spring type, i.e. requiring no fastening screws; as further illustrated, in fact, the mechanical solidity of the connection between the cable 4 and the socket 1 is, according to the present invention, warranted in a different way. Finally, in Fig. 3, with 1 1 indicates a cavity defined within the socket 1, which extends from the housing AA towards the conductor element 8; said cavity 1 1 is apt to receive a portion of the basket 7 which extends out of the carriage 5, and in particular the portion of the basket 7 extending over the bending IC of the wings 7C. It should be noticed that a shrinkage indicated with 1 1 A, whose functions will be cleared in the following, is defined between the housing AA and the cavity 11 ; moreover, seats not shown in the figures are defined substantially in this zone, on the inner surface of the housing AA and of the cavity 1 1 , wherein the wings 7C are apt to insert. The operation of the socket according to the present invention is now described with reference to its preparation and installation operations. First of all, the installer of the socket 1 has to extract a small portion of the cable 4 from the canalization or tube - not shown in the figure - wherein said cable is inserted. Then the cable 4 is stripped down in its end part, indicated with X+Y in Fig. 3, for about two centimeters of length, by removing a portion of its outer sheath 4D; subsequently, in the part X of the cable 4, a portion of the central conductor 4C is laid bare for about 1 cm length, by removing an equal portion of the plait 4A and of dielectric material 4B (and the likely aluminium band); therefore, the remaining bare portion of the plait 4A, with the likely aluminium band, remains extended on most part of the remaining dielectric material 4B, which is located in the part Y of the cable 4. It should be noticed that, at this point, the installer already has a pre-assembled socket available, for example delivered by the manufacturing company itself; such a pre-assembly of the socket comprises in particular: the basket 7 already inserted in the central cavity 5 A of the carriage 5; as mentioned above, the mechanical connection between the basket 7 and the carriage 5 is obtained by making the projections 7D of the former to engage in the appropriate cavities 5C of the latter; obviously, other known methods are possible for achieving a coupling between the parts 7 and 5 : the carriage 5 - basket 7 assembly, being already inserted in the housing AA and the cavity 11, both of them provided in the screening body 2 with its preliminary mechanical tightening; this is substantially obtained by means of a partial screwing, i.e. just for a few turns, of the screw 6 in the threaded cavity 5B of the carriage 5, through the proper passage 2 A provided in the screening body 2. As a result, the installer entrusted with the connection, will simply have to insert the cable 4, stripped as above explained, down to the bottom in the basket 7. In this stage, due to their flexibility, the wings 7C of the basket 7 can open out, so as to allow the portion of the dielectric 4B bearing the plait 4 A externally to slide; the special "funnel" bending of the set of wings 7C will appropriately guide the dielectric 4B, so facilitating the penetration of the central conductor 4C in the appropriate spring contact 8A to obtain the relevant electric connection. During this insertion stage, also the wings 7B of the basket can open out, so allowing the unstripped portion of the cable 4 to pass; the wing ends 7B' can rest on the outer sheath 4D of the cable itself. Finally, the installer will tighten the screw 6. The linear movement of the carriage-basket assembly, due to this screwing, will cause a progressive interference of the wings 7B with the shrinkage 11A of the screening body 2; therefore, the wings 7B are pushed to bend or flex towards the inside, to have their ends 7B' fixedly pressed on the cable sheath 4D, thus ensuring a good mechanical connection. This pressure results in being even on the circumference of the cable 4, so that appreciable distortions of the dielectric 4B are avoided while the concentricity of the cable 4 is maintained; on the contrary, according to the present invention, it is the connection element consisting of the basket 7 which changed its configuration, to match the cable 4. Obviously, for the above interference to occur, it is necessary that the carriage 5 integral with the bushing 7 is shorter than the wings 7B. Moreover, due to the shape and the inclination of the ends 7B', any attempt to extract the cable 4 from the socket 1 will cause the pressure of the wings 7B to increase on the sheath 4D, all the more reason for hindering a cable exit from the socket. As previously said, the wings 7B are preferably in number of six; also the longer wings 7C are preferably in number of six and can slide with a certain interference in the seats defined on the surface of the housing AA and of the cavity 1 1, i.e. on surfaces of the screening body 2; therefore, since the wings 7C consist of mechanically elastic and electrically conductive material, a good electric contact is ensured between the basket 7 and the body 2. Therefore, as it can be seen, a simple inserting operation of the cable 4 and just one easy screwing of the screw 6 ensures at the same time both a sturdy mechanical connection between the socket 1 and the cable 4, and a good electric connection between the plait 4A and the screening body 2, through the elastic pressure exerted by the wings 7C. Obviously, the cable 4 may be extracted from the socket 1 , if required, by simply loosening the screw 6, and pulling the cable towards the outside. Once the above operations have been performed, so that also the electric and mechanical connections for the conductors 4A and 4C are obtained, the socket 1 can be inserted in the suitable wall box. and fastened there. From the above it is clear how according to the present invention no ground U-bolts are necessary, thus avoiding squeezing risks for the cable 4 and consequent impedance mismatching, due to coaxiality losses. Similarly, the integral locking between the cable 4 and the socket 1, as well as the connection between the central conductor 4C and the socket, are obtained with just one screwing operation, without the need of handling several components simultaneously, nor producing mechanical deformation on parts of the elements 4, such as its plait or outer sheath, as in the instance of IT-B-1.287.047 and IT-B- 1.289.463; as a result the installer's job is considerably simplified. Since no U-bolts are necessary and the single screwing operation required being easy, the preparation of the socket according to the invention may be carried out by extracting only a minimum length of the cable 4 from its canalization or tube, so that when the socket is inserted in the relevant box, any cable bending and/or squeezing is further reduced. Moreover, from the above, it is also clear how a the quality of the connection between the cable 4 and the socket is always ensured, being it practically independent from the installer' skill. Similarly, according to the present invention, the screening of the connection of the central conductor 4C of the cable 4 is always ensured, by means of the screening body 2, the latter being made from conducting material, which fully enwraps all electric parts. Moreover, it is also apparent from the above how the socket according to the present invention may be indifferently used for the connection to cables conveying analog signals or cables conveying digital signals, while ensuring all the above advantages in both instances. It is also clear how the basket 7, in particular due to its elastic structure allows for the use of cables having various external diameters, such as ranging from 5 mm to 7 mm, as the case may be. In Figs. 1, 2 and 3 a socket 1 has been represented, for simplicity's sake, connected to one coaxial cable 4 only, and having one sole connector 3 for picking up the output signal; however, it is clear that the present invention can also be easily extended to sockets connected to several cables, also provided for conveying different types of signals, and fitted with one or more outputs, as illustrated in Fig. 6. This figure shows a schematic view from below (referring to a view of the type illustrated in Fig. 1) of a socket 1A provided for receiving two coaxial cables, apt for carrying signals of different type, and having on its front part of one or more connectors as those previously indicated with 3 (one of which alone can be seen in Fig. 6); in this figure the same reference numbers of the previous figures are partially used to indicate technical equivalent elements; for clarity's sake, the cables are not represented in Fig. 6. In the instance of the dual socket 1A illustrated in Fig. 6, the following elements will be therefore provided for each cable: a carriage 5, with relevant housing AA within the screening body 2, a basket 7, with a relevant cavity 1 1 and shrinkage 1 1 A within the screening body 2, a fastening screw 6. Therefore, as it can be seen, in this case the connection of each cable to the socket 1A can be performed independently, whereby the assembly operations will be considerably easier compared to the present state of art. The general structure represented in Fig. 6 can also be used for sockets of other different types (such as through-sockets, mixing sockets, de-mixing sockets) and it is clear that WO 00/67347 . PCT/IBOO/00535 - 14 - according to the function performed by the socket, the latter may have one or more connectors 3; similarly, according to the function performed by the socket, the latter will be fitted with suitable insulating, connecting and/or circuitry means, for realizing the appropriate transfer and/or treatment of the signal or signals being destined to the connector or connectors provided by the socket. As it can be imagined, the operations for preparing the connection and the assembly of the socket according to the invention illustrated in Fig. 6 are similar to the ones previously described with reference to Figs. 2 and 3. From the above description the features of the present invention are clear. In particular a device for the screened connection of at least a cable 4 has been described, comprising at least two conductors 4A and 4C for conveying video and/or audio and/or data signals; the device 1 comprises a body 2 to which a connection element 7 is associated, being in contact with the cable 4 and capable of movement with respect to the body 2, where fastening means 5 and 6 for locking the connection element 7 to the body are provided. According to the invention, the connection element 7 is capable of changing its own configuration with respect to the cable 4, and not vice-versa, in order to realize a mechanical and/or electric coupling between the cable 4 and the connection element 7; this is achieved following a movement of the connection element 7 with respect to the body 2, as imparted though the fastening means 5 and 6. Also a method for the connection of a coaxial cable 4 to a connection device 1 has been described, where in order to connect the cable 4 to the device 1 the following steps are provided: a) from an end portion X+Y of the cable 4 a part of a first insulating material 4D is removed, for access to a first conductor 4A of the cable 4; b) from a part X of said end portion X+Y of the cable 4 a portion of the first conductor 4A and a portion of a second insulating material 4B are further removed, for access to a second conductor 4C of the cable 4; c) the two conductors 4A and 4C are electrically connected to the device 1 and the cable 4 is mechanically connected to the device 1. According to the described method, the mechanical connection of the cable 4 to the device 1 is obtained: - associating the cable 4 to a connection element 7, which is inserted in a body 2 of the device 1 and fastened to it; - determining a movement of the connection element 7 with respect to said body 2, such to produce a change of configuration of the connection element 7 on the cable 4, and not vice- versa, apt for mechanically retaining the latter to the device 1. Further detailed features of the present invention are, as said, listed in the annexed claims. According to the given description also the advantages of the present invention are clear. In particular: - the screening of the connection of the central conductor 4C of the cable 4 is always assured by the screening body 2, which is made from conductive material and is enwrapping the socket entirely; - no ground U-bolts are required, so that the cable 4 cannot results in being squeezed and mismatching due to coaxiality losses is avoided; - the integral locking of the cable 4 to the socket 1 and the connection of conductors 4A and 4C to the socket 1 are obtained with just one screwing operation, so that the installer's job is considerably simplified; since no U-bolts are required, the preparation of the socket according to the invention is possible by extracting only a minimum quantity of the cable 4 from its canalization or tube, so that bending and/or squeezing of the cable are minimized when inserting the socket in the relevant box, so avoiding further signal alterations; - the connection system described herein does not entail substantial mechanical deformations to cable parts, during the mechanical and electric fastening of the cable; - the screened connection described herein can be used with various types of cable, also with different sections; this is allowed by the capability of deformation of the basket 7 and in particular of the wings 7B and/or 7C, which allow the use of cables of various external diameters, for example ranging from 5 mm to 7 mm. - uncoupling and disconnection risks due to undesired cable pulls are reduced, by virtue of the special shaped ends 7B' of the wings 7B. - the fastening of several cables, in the instance of multiple connections, is simpler. Finally, a substantial advantage of the present invention is that the connection, the screening and the coaxiality of the cable are substantially always warranted, independently from the installer's skill. It is obvious that many changes are possible for the man skilled in the art to the connection device and the method described above by way of example, without departing from the novelty spirit of the innovative idea, and it is also clear that in practical actuation of the invention the components may often differ in form and size from the ones described and be replaced with technical equivalent elements. The connection system object of the present invention may be used for example in devices apt to connect two or more screened cables to each other, without any signal socket, but where a good screening is anyway required, as in the instance of dividers, shunters and inline sockets for screened cables, conveying video and /or audio and/or data signals. In such an event, with reference to Figs. 1 and 2, the connector 3 will be omitted, whereas the insulating support 10 will be used for the electric connection of the central conductors 4C of the cables, eventually by means of electric components. In the event of the assembly described by way of example with particular reference to Fig. 3, the plait 4 A results in being extended on the dielectric 4B of the cable 4. On the other hand, nothing hinders a back folding of the plait 4A, i.e. over the cable sheath 4D; such a change is represented in the variant embodiment of Fig. 7. In this instance, the function of the electric connection between the body 2 and the plait 4A is obtained by means of the wings 7B, whose ends 7B' will have a dual function as mechanical and electric connection. In this application, should the cable be fitted with the above aluminium band between the plait 4 A and the dielectric 4B, the latter may be anyway maintained extended on the dielectric 4B; thus, besides the electric connection between the plait 4A and the wings 7B, the electric connection would be warranted also between said band and the wings 7C. Another possible variant provides for realizing the carriage 5 and the basket 7 in one sole piece, by forming for example the section 7A of the basket with a side portion, wherein a threaded passage is delimited apt to receive the screw 6; it is clear that in this instance the number of components of the device can be reduced. Finally, it is clear that the invention described above with reference to a socket can be easily and usefully employed also in the instance of plugs for cables, particularly of the coaxial type.

Claims: CLAIMS 1. A device for the screened connection of at least a screened cable (4), in particular a coaxial cable, comprising at least two conductors (4A,4C) for conveying video and/or audio and/or data signals, said device comprising a body (2) to which a connection element (7) is associated, in contact with said cable (4) and capable of movement with respect to said body (2), where fixing means (5.6) are provided for locking said connection element (7) to said body (2), characterized in that said connection element (7) is capable of changing its configuration with respect to said cable (4), in order to realize a mechanical and/or electrical coupling between said cable (4) and said connection element (7), following a movement of said connection element (7) with respect to said body (2), imparted in particular through said fixing means (5,6). 2. A device, according to claim 1 , characterized in that said fixing means (5,6) comprise a locking element (5) capable of movement and fastening means (6) apt for fastening said locking element (5) to said body (2), the movement of said connection element (7) being determined by a movement imparted to said locking element (5) through said fastening means (6). 3. A device, according to claim 1 or 2, characterized in that said connection element (7) comprises parts (7B,7C) being mechanically and/or elastically deformable. 4. A device, according to claim 2. characterized in that said connection element (7) is coupled to and/or made integral with said locking element (5). 5. A device, according to claim 1 or 2, characterized in that said connection element (7) comprises first parts (7B) for the coupling to a first zone of said cable (4). 6. A device, according to claim 5, characterized in that said connection element (7) comprises second parts (7B), for the coupling to a second zone of said cable (4). 7. A device, according to claim 5 or 6, characterized in that said first and/or second parts comprise each one at least a pair of elastic elements (7B,7C) between which said cable (4) is passing through. 8. A device, according to claim 5 or 6, characterized in that said first and/or second parts comprise flexible wings or leaves (7B,7C). 9. A device, according to the previous claim, characterized in that first wings (7B) and second wings (7C) are provided, having different lengths and/or shapes between them, in particular the first wings (7B) being alternated to the second wings (7C). 10. A device, according to at least one of the previous claims, characterized in that said first and/or second parts (7B,7C), or elastic elements, or first and/or second leaves, define a guide for the correct insertion of said cable (4) within said body (2). 11. A device, according to at least one of the previous claims, characterized in that said first and/or second parts (7B,7C), or elastic elements, or first and/or second leaves, are apt to realize an electric connection between a first conductor (4 A) of said cable (4) and said body (2), which is obtained from an electrically conductive material. 12. A device, according to at least one of the previous claims, characterized in that said first parts (7B,7C), or elastic elements, or first leaves, are apt to change their configuration following their interference with a portion (1 1 A) of said body (2), so as to obtain a gradually increasing strong coupling with said cable (4). 13. A device, according to at least one of the previous claims, characterized in that said second parts (7B,7C), or elastic elements, or second leaves, are apt to elastically change their configuration following the insertion of said cable (4) between them, in order to obtain an elastic coupling with said cable (4). 14. A device, according to at least one of the previous claims, characterized in that at least to a coaxial connector (3) is associated to said body (2), said connector (3) comprising in particular a central conductor (3A) and a perimetric conductor (3B). 15. A device, according to at least one of the previous claims, characterized in that means (8,8A) are provided, for the electric connection of a second conductor (4C) of said cable (4), said means comprising at least an electric connecting element (8A) apt to receive and elastically retain at least a portion of said second conductor (4C). 16. A device, according to at least one of the previous claims, characterized in that said locking element (5) comprises a first cavity (5B) apt to receive a portion (7A) of said _ connection element (7). 17. A device, according to at least one of the previous claims, characterized in that said first and/or second parts (7B,7C), or elastic elements, or first and/or second leaves protrude out of said first cavity (5B). 18. A device, according to at least one of the previous claims, characterized in that said locking element (5) comprises a second cavity (5 A) apt to receive a screw (6). 19. A device, according to at least one of the previous claims, characterized in that said locking element (5) is capable of sliding within a first housing (AA) defined in said body (2). 20. A device, according to at least one of the previous claims, characterized in that said connection element (7) is capable of sliding in a second housing (11) defined in said body (2). 21. A device, according to claims 19 and 20, characterized in that a shrinkage (1 1A) is defined between said first and second housing (AAJ 1), with which at least a part (7B) of said connection element (7) is apt to interfere. 22. A device, according to at least one of the previous claims, characterized in that said first leaves (7B) have an inclined end (7B') and/or said second leaves (7B) have at least two bendings (7C',7C"). 23. A device, according to claim 1, characterized in that, following said configuration change, the degree of mechanical coupling between said cable (4) and said connection element (7) is apt to increase, in case of pulls to said cable (4) in an opposite direction with respect to said movement of said connection element (7). 24. A device, according to at least one of the previous claims, characterized in that said connection element (7) defines an internal passage, apt to receive a coaxial cable (4). 25. A device, according to at least one of the previous claims, characterized in that said internal passage is apt to receive cables having different sections and/or diameters. 26. A device, according to at least one of the previous claims, characterized in that said second parts (7C) are apt to elastically press on a portion of an insulating material (4B) of a — ± — coaxial cable (4), with an interposed portion of at least a ground plait (4A) and/or a band. 27. A device, according to at least one of the previous claims, characterized in that said first parts (7B) are apt to be elastically or mechanically pressed on an outer sheath (4D) of a coaxial cable (4), with the likely interposition of ground plait (4 A). 28. A device, according to at least one of the previous claims, characterized in that said connection element (7) is obtained at least partially from a mechanically elastic or electrically conductive material, such as phosphorous bronze or beryllium copper. 29. A device, according to at least one of the previous claims, characterized in that a number of connection elements (7) is provided, corresponding to the number of cables to be connected (4). 30. A device, according to the previous claim, characterized in that a number of locking elements (5) is provided, corresponding to the number of cables (4) to be connected. 31. A device, according to at least one of the previous claims, characterized in that it is a signal divider or shunter, or a plug, or a socket for screened cables. 32. A device, according to at least one of the previous claims, characterized in that said connection element (7) comprises a passage apt to receive a screw or similar (6) being part of said fixing means. 33. A method for the connection of a coaxial cable (4) to a connection device (1), where for the connection of the cable (4) to the device (1) the following steps are provided: a) from an end portion (X+Y) of the cable (4), a part of a first insulating material (4D) is removed, so as to have access to a first conductor (4A) of said cable (4); b) from a part (X) of said end portion (X+Y) of the cable (4), a portion of the first conductor (4 A) and a portion of a second insulating material (4B) are further removed, so as to have access to a second conductor (4C) of said cable (4); c) the two conductors (4A,4C) are electrically connected to the device (1) and the cable (4) is mechanically connected to the device (1), _ 22 _ characterized in that the mechanical connection of said cable (4) to said device (1) is realized: - by associating said cable (4) to a connection element (7), which is inserted in a body (2) of said device (1) and secured to it; - by determining a movement of said connection element (7) with respect to said body (2), such to produce a change of configuration of said connection element (7) on said cable (4), apt for mechanically retaining the latter to said device (1). 34. A method, according to claim 33, characterized in that the change of configuration of said connection element (7) occurs on a portion of said cable (4) which is different from said end portion (X+Y). 35. A method, according to claim 33, characterized in that the configuration of said connection element (7) changes for matching on said first insulating material (4D). 36. A method, according to claim 33, characterized in that the change of configuration of said connection element (7) is also apt to realize an electric connection of said first conductor (4A) to said device (1). 37. A method, according to claim 33, characterized in that the electric connection of said first conductor (4A) to said device occurs by means of elastic parts (7C) of said connection element (7). 38. A method, according to claim 33, characterized in that the electric connection of said second conductor (4A) to said device occurs by means of elastic parts (8A) of said connection element (7). 39. A method, according to claim 33, characterized in that the change of configuration of said connection element (7) occurs following its interference with a part (HA) of said body (2). 40. A method, according to claim 33, characterized in that the capability of said connection element (7) to mechanically retain said cable (4) increases in the case the latter is pulled in an opposite direction with respect to said movement of said connection element (7).

Inventors: RACCANELLO GIANCARLO, SALVALAGGIO FABIO, RACCANELLO, GIANCARLO, SALVALAGGIO, FABIO
Applicants: FRACARRO RADIOINDUSTRIE, RACCANELLO GIANCARLO, SALVALAGGIO FABIO, FRACARRO RADIOINDUSTRIE S.P.A., RACCANELLO, GIANCARLO, SALVALAGGIO, FABIO
Application year: 2000
Main classification: H01R9
IPC codes: H01R9, H01R13