WO2009011006A1

WO2009011006A1 - System of solderless coaxial connectors and methods for their manufactures

Info

Publication number: WO2009011006A1
Application number: PCT/IT2008/000466
Authority: WO
Inventors: Enrico Barelli; Claudio Villa
Original assignee: Compel Electronics S.P.A.
Priority date: 2007-07-17
Filing date: 2008-07-11
Publication date: 2009-01-22
Also published as: ITMI20071433A1

Abstract

In the connectors according to the invention between the central contact present in the complementary connectors, and the terminal of the central of the coaxial cable is carried out by means of interface coupling which are exclusively mechanical in total absence of soldering.

Description

SYSTEMS OF SOLDERLESS COAXIAL CONNECTORS AND METHODS FOR THEIR MANUFACTURE.

FIELD OF THE INVENTION

The present invention refers to coaxial connectors (CO) for coaxial cables, substantially comprising: - two complementary bodies one female and the other one male (A₅ B); - a first central contact (Al, Bl) in said connectors (CO) for the electrical signal passage; - a second outer contact (A3, B3) for the ground connection; - dielectric elements (A2, B2) interposed between said two contacts; - caps or taps to associate to the distal ends of each complementary body (A, B); and - backend connectors for the passage of stripped terminals of said coaxial cables.

Typically the fixations of said coaxial cables to said central contacts (Al, Bl) does not involve soldering or welding operations.

The invention comprises also advantageous and therefore preferred methods for the solderless embodiments of the irremovable fixations of said terminals passing through said backend connectors, to said central contacts of the coaxial connectors (CO).

PRIOR ART

The conventional connectors (as mentioned in the preambles of this description and of claim

1) consist generally of two complementary parts: female semi connector (A) and male semi connector (B)₅ each formed by a central contact (Al₅ Bl) through which the signal travels, by an outer contact (A3, B3) for the ground connection, and by one or more dielectrics (A2, B2)₅ interposed between said two contacts. There are possibly other accessory elements which allow the stable connection between said two complementary parts or to the devices with which said last parts are destined to operate. By fixing together male connector (B) and female connector (A) the work operative condition is realized and the signal can flow.

Generally the connectors are used to connect/disconnect two or more circuits, devices or apparatus. The connection to these circuits can take place in several ways: - by means of a direct connection (soldering- or press fit- technique) on a printed circuit board; - by connection of wires to connectors mounted on metallic panels or by means of coaxial cables which can connect devices located at high distances. With reference to this last case, the central conductor of the coaxial cable (A) must be easily connectable to the connector central contact (Al, Bl). There are several techniques to carry out this operation, f.i. by clamping, soldering crimping. Each one of these techniques can be applied either for the connection to said central conductor (CAl) of the coaxial cable, or for the connection to said outer central conductor (CA3) (shield).

Said techniques are also applicable both to the straight or angular connectors. For these last angled connectors the connection of the central conductor (CAl) is generally carried out by means of the soldering technique which gives, to-day, the best qualitative guarantees and the right compromise performances/costs.

It is however a rather long, delicate and expensive system and needs always an electric energy source (not always available, especially in the frequent cases of field work). It requires skilled workers and nevertheless does never give repetitive products, i.e. products with standard characteristics.

Even with this inconveniences the soldering technique has always been accepted as the minor evil and, at the best knowledge of the inventors, attempts have not been traced (up to now) of solder less connectors, at a parity of all other conditions.

SUMMARY OF THE INVENTION First object of the present invention is to provide coaxial connectors, preferably according to the main claim preamble, without the inconveniences of the Prior Art, in particular without the above mentioned drawbacks.

An other object is to provide coaxial connectors for coaxial cables, solderlessly fixed to the central contact of said connectors.

An other object is to provide coaxial connectors wherein for the irremovable solderless fixation of the angled coaxial cable terminal, use is made of pushing means associated to complexes taps.

A further object is to provide coaxial connectors for coaxial cables wherein the connection between the connector central contact and the stripped terminal of the coaxial cable central conductor is carried out by means of slide fit means.

Finally a further object of the present invention is to provide simple and efficient methods to bring about the anchorages of the stripped central conductor of the coaxial cables to the central contact of the angular connection by using exclusively mechanical coupling without fusible material contribution.

The most salient characteristics of the connectors and of the manufacturing methods thereof, according to the present invention are recited in the claims at the end of this description, which are however to the considered herewith incorporated. BRIEF DESCRIPTION OF THE ACCOMPAINING DRAWINGS

The various features and advantages of the invention will clearly appear from the description of the embodiments represented in the accompanying drawings, to the figure numbers of which are associated significant letters such as E, F, S and P which design respectively: - E, exploded and/or prospective views; - F, frontal views; - S, cross-section views; and - P, top views, whereby the so numbered and "lettered" figures represent now: figures IE and 2E, prospective exploded and compacted views of conventional connectors; figures 3E and 4E, prospective (exploded, compacted) views of the first embodiment of the invention, with a pressing mechanism MP; fig. 4P, a top view of fig. 4E; figures 5F and 5 S, front, respectively cross-sectioned views of the closing cap TC incorporating the pressing mechanism MP; figures 6F and 6'F and the relevant figures 6S and 6' S, front-, respectively, top-views of the manoeuvre piston PM of the mechanism MP of figures 3E and 4E; figures 7E and TE, prospective views of the elastic element EE of the mechanism PM in its alternative version; figures 8F and 8S are front-respectively cross-sectioned views of the bush or sleeve of the push system i.e. with the pressing mechanism MP; fig. 9, prospective view of the central contact portion interested to the pressing mechanism MP; such a portion is seen as inserted and positioned in the relevant part of connector CO to receive said connection mechanism of the invention; figures 10E₅ 10AE, prospective views of alternative solutions of the first embodiment of the invention showing the pressing mechanism MP; figure 1OS is a cross-sectioned view of fig. 1OE, whereas fig. IOAP is a top view of fig. 10AE; fig. 1 IE, a prospective partially cross-sectioned of the fixation zone to the coaxial cable CA by means of said slide fit system, said cable CA being seen as totally inserted; figures 12F, 12S and 12'S are frontal-,respectively cross-sectioned views (on enlarged scale) of the slide fit contact (Cl) of fig. HE; - fig. 13E is a perspective view of the central contact (CCA) portion interested to the connection of the central conductor CAl of coaxial cable CA through the slide fit mechanism according to the invention; and

- figures 14, 15 and 16 are block schemes of the conventional, respectively inventive methods.

DETAILED DESCRIPTION OF INVENTION

According to the most important characteristics of the invention, the connection between the connector central contact and the coaxial cable inner conductor terminal is no more embodied by high temperature fusible material contribution (typical of the soldering process) but by exclusively mechanical coupling between said central conductor and interfaces created on the system components. Preferably this coupling is carried out with the aid of pressure (push) or slide fit organs associated preferably to a connector component and/or the central conductor terminal of the coaxial cable.

Push Coupling ffigures 3E. 4E. 4P. 5S. 5F. 6F. 6T. 6S. 6'S. TE. 7Ε. 8F. 8S. 9. IQE. IPS.

IQAE. and IQAP.)

This coupling is obtained by inserting a pressing mechanism within the connector closing cap.

The connector main parts remain substantially equal to the existing ones. On the contrary the closure cap TC is transformed from a simple particular piece into an assembly of several pieces capable to transmit a compression force between the connector central contact (Al,

Bl) and the coaxial cable central conductor (CAl).

The cable CA assembly can be summarized in the following steps; - cable stripping; - stripped terminal insertion into the connector; - crimping or clamping of said cable outer conductor; - screwing of the closure cap carrying the pressing mechanism MP. The central conductor (CAl) welding to the connector central contact CC (conventionally carried before the cap screwing) is thereby eliminated. The pressing mechanism (of figures

3E, 4E, 4P) can now simply consist of following elements:

- A closure cap TC so modified to be able to receive the various components of mechanism MP. At this end, a hole TCl with a single or double step (with directing chamfers) is present to position and make possible the movements of the other components mechanism. In the back part an adequately formed slot TC2 is present to consent the reception of the manoeuvre tool to screw said cap TC into the connector CO. Outwardly is present a profile (smooth or shaped) TC3 (fig. 5F) which ends up with a threaded zone TC4 to allow the assembly of TC in the relevant threaded place COl of the connector body CO. In said pressing mechanism (figures 6F, 6S, 6'F₅ 6' S) is present a small manoeuvre piston PM, generally of isolating material ( or metal coated with isolating material) generally consisting of several cylindrical parts having different functions. The back cylindrical part PMl supports and guides an elastic element EE during its work and rest conditions. A further cylindrical part PM2 (with major diameter) follows with the function of creating a projection PM7 to stop the piston PM within the manoeuvre mechanism, in the absence of which said piston PM would be pushed outside by the elastic element (figures 7E, 7'E); on the contrary the successive cylindrical part PM3 has the function of support and guide during the passage between the work conditions and the rest. The last cylindrical part PM4 contributes actively to the connection between the cable CAl central conductor and the connector CC central contact. The profile can be different in accordance with the solution adopted to transfer the compression on the cable. The full cylindrical part P4 allows to push the cable on the whole lateral surface PM8 by pressing it on the more or less extended zone of the connector central contact CC. The cylindrical profile with lateral central hole PM5 (shown as alternative version in figure 6) allows to push the cable on two zones of the central contact as it is compressed by the lateral circular crown PM6 of the manoeuvre piston PM.

The elastic element EE is generally made of metallic or insulating material and has a shape adequate to submit to a continuous axial force said small piston PM so to guarantee a uniform and time-constant contact. The shape can be different according to the solution adopted from the classical spiral spring or other compressing springs, to the traditional gasket or any other equivalent profile able the give the requested function. The supporting bush BS in metallic or plastic material consists generally of outer cylindrical parts and an inner hole BSl which guides piston PM during the work conditions. Outside, a first cylindrical part BS2 is generally forced in the cap TC and allows the fast capture of piston PM and elastic element EE within same cap. A second cylindrical part B S3 guides the blocking system when it is being inserted in the connector body CO by crewing. In an alternative version this cylindrical part BS3 goes to interfere with the connector body CO during the assembling so to form a rigid coupling which allows to maintain the connection between cable CAl central conductor and connector central contact even in the case of the unscrewing of cap TC. This or other equivalent alternatives allow to obtain this advantage at a loss of a light cost increase due to the major number of pieces.

The metallic central contact CC (fig. 9) of the connector is generally identical to the existing one or is only slightly modified. In the part inherent to the invention said contact CC consists of an outer cylindrical part CC2 with a head slot CCl obtained by mechanical working, in which shall take its position the cable CAl central conductor during its assembling to the connector. At the end of said slot there is a transversal hole CC3 where the cable central connector will be pushed by the piston PM to create thereby a clamp effect that optimizes the contact with the central contact CC; two points are indeed formed in which the cable central conductor CAl is firmly blocked. In alternative versions said hole CC3 cannot be present, and in this case a plan is formed which is the work zone of the system according to the invention and is able to function with all the utilizable solutions of the manoeuvre piston PM.

The connector body CO (figures 9F) of metallic material is generally identical to the conventional body or is slightly modified. In the invention inherent part the connector body CO consists of a cylindrical part CO2 with an inner cavity CO3 at the beginning of which a threaded zone COl is present which allows the screwing of the closure mechanism through cap TC. In cavity CO3 is seated central contact CC with its slot CCl where the cable central conductor shall go to seat.

Slide fit coupling (figures HE. 12F. 12S. 12'S and 13F). It is obtained by inserting a transversal spring mechanism, by connecting it to the connector central contact whose major part remains substantially equal to the existing one. Also the assembly of the cable remains substantially equal to the push system, maintaining the same advantages. The slide fit mechanism comprises: - a slide contact CI (figures HE and 12E) in metallic elastic material, consisting of a first cylindrical part CIl (with the relevant chamfers at the ends thereof) which acts as support and stop during the insertion of said CIl in the connector central contact CCA. On the contrary the final surface CI2 can act during the coaxial cable CA insertion by acting as stop of the cable dielectric CA2. The second cylindrical part CI3 is generally smooth or knurled and has the function to electrically and mechanically connect the slide contact CI to the connector CAA central contact forming thereby a fixed and rigid system. The last part CI4 (fig. 12) shows externally two or more slots (CI5) so to bend the resulting springs CI6 and create an elastic junction in which the cable central conductor CAl is pushed which CAl, by interfering with said bent springs CI6, tries to open them by generating a pressure contact between springs and cable conductors and therefore a stable connection. The interior of the slide contact CI comprises a first conical surface CI6 (fig. 12S) of convenient size, which allows the entry of the cable central conductor CAl within the slide contact CI during the cable assembly. The second cylindrical inner part CI7 guides the cable central conductor CAl and in its final portion (because of the bent springs

CI6) are present the contact surfaces CI8 between cable conductor CAl and slide contact CL The connector central contact CCA in metallic material is generally identical or slightly modified over the conventional one. In the portion inherent to the invention the contact is made of a cylindrical part CAAl with a head slot CAA2 which has no functional role but can serve as positioning member during the connector central contact CCA assembly. On the outer cylindrical zone there is a hole CCA3 which is the good seat to receive and connect mechanically and electrically the slide contact Cl.

The block schemes of figures 14, 15 and 16 show and compare the conventional manufacturing methods (fig. 14) to those according to the invention made by the push technique (fig. 15) and the slide fit technique (fig. 16). In the conventional process the steps are:

1. Bodies of male connector and female connector are separately predisposed;

2. Said two half-bodies containing the conventional central contact are assembled;

3. Coaxial cable central conductor is stripped;

4. Said stripped terminal is inserted in the connector crimping sleeve;

5. Said terminal is blocked by crimping the outer contact;

6. Is welded in the connector contact; and

7. The connector is closed with a conventional cap. In the two methods according to the invention the steps from 1 to 5 are kept unchanged however step 6 of the soldering operation disappears. In the method of fig. 15 the special contact 3' is obtained by pushing on the pressing cap MP whereas in the method of fig. 16 same special contact is obtained by the contribution of the slide device CI.

Claims

1) Systems of coaxial connectors for coaxial cables, each connector (CO) comprising at least: - - two complementary bodies, i.e. a female body (A) respectively a male body (B); - a first central contact (Al, Bl) in said connector (CO) of electric signal transit; - a second outer contact (A3, B3) for the ground connection; - dielectric elements (A2, B2) positioned between said contacts; - caps to be associated to the distal end of each complementary body (A, B); and - backend connectors for the passage of the stripped terminals of said coaxial cables, characterized by interfaces of exclusively mechanical couplings between connector central contacts and coaxial cable conductor.

2) System according to claim 1, characterized by an interface produced by a pressure mechanism (MP) firmly associated to the closure cap (TC).

3) System according to claim 2, characterized in that said pressure mechanism (MP) comprises a head tapered with a stepped anterior hole, a posterior slot shaped to receive a screwing tool, and an ending part with a threaded zone for its mounting in the threaded seat of the connector body.

4) System according to claim 3, characterized by a push organ comprising a manoeuvre small piston PM having: - a central cylindrical portion of major diameter PM2 creating a stop PM7 for said piston and is integral with a cylindrical posterior portion PMl of support and guide of an elastic element EE; and - a cylindrical major portion (PM3) integral, on its turn, with an anterior projecting portion having a minor diameter, and so shaped to produce an optimal compression between coaxial cable and connector central contact. 5) System according to claim 4, wherein the elastic element (EE) substantially comprises an helicoidally or cup spring, a rubber small piece and an O-ring.

6) System according to claim 5, comprising a bush or sleeve (BS) having a guide hole (BSl) for the piston (PM) during its work condition and an outer cylindrical portion (BS2) forced in the closure cap (TC).

7) System according to at least one of previous claims, wherein in order to create a first modification interface, the connector (CO) central contact (CC), consists of an outer cylindrical portion with a head slot (CCl) to position the coaxial cable central conductor (CAl), and of a transversal hole (CC3) in which said terminal (CCl) will be pushed by the piston producing a clamp effect.

8) System according to at least one of previous claims, wherein the connector body (CO) consists of a cylindrical portion (CO2) with an internal cavity (CO3) which is at least partially threaded to screw the closure cap, and has a housing for the central contact (CC) with slot (CCl) for the cable central conductor.

9) System according to claim 1, characterized by an interface which forms a slide fit mechanism (CI), comprising: - a central portion (CΙl)for the insertion of (CI) in the central contact (CCA) of connector (CA), having a lower face (CI2) acting as a stop and catch during the coaxial cable insertion; - a cylindrical portion (CB) with a minor diameter, integral and projecting from (CIl) for the fixed and rigid electro-mechanical connection of said (CI) to said connector central contact (CCA); and - a terminal portion (CI4) projecting from (CD) and having at least two pins (CI5) preferably with elastic springs or wings (CI6) to create a junction between said springs and the central conductor terminal. 10) System according to claim 9, in which a cylindrical portion (CI7) inside portion (CD) is provided with contact surfaces (CI8) between the coaxial cable central contact (CAl) and said slide contact (CI).

11) Method to manufacture connection systems according to the above claims 1-10, wherein the coaxial cable terminal is stripped, is inserted into the connector "ad hoc" backend and, in the absence of welding, interfaces are brought about, in particular push-or slide fit interfaces to make irremovable, mechanically solid and electrically dispersion free junctions, between the components consisting of the connector central contact and the coaxial cable stripped terminal, said interfaces being obtained by simply modifying the components of said connection systems.