WO1996020516A1

WO1996020516A1 - Coaxial cable connector

Info

Publication number: WO1996020516A1
Application number: PCT/US1995/016856
Authority: WO
Inventors: David Bliven; Edward A. Cydzik; Michael Hobson; Donald Micheletti; Karen G. Roney; Khalid A. Waheed; J. Kendall Williams
Original assignee: Raychem Corporation
Priority date: 1994-12-23
Filing date: 1995-12-21
Publication date: 1996-07-04
Also published as: AR000535A1

Abstract

A coaxial cable connector (100) is described which upon installation affects a seal both to a cable splice (400) and cable tap port (500) as well as the outer dielectric (440) of the cable. The push-on pull-off connector provides positive tactile response to the installer to ensure a proper installation.

Description

COAXIAL CABLE CONNECTOR

Technical Field of the Invention

The invention relates to a coaxial cable connector. In particular the invention relates to a coaxial cable connector for flexible coaxial cable such as RG59 and/or RG6 single braided and/or quad shielded cable.

Background of the Invention

Coaxial cable is used widely in the communication industry. In particular coaxial cable is used to transmit television and other signals in the cable television industry and the like. When such cable needs to be routed through an apartment building or a house or from a distribution point, a flexible shield cable is generally used. This cable contains a center conductor along which the signals are transmitted, surrounded by a dielectric and one or more shielding layers of foil or wire metal braid, surrounded by an outer dielectric. In the past, crimp connectors have been utilized to create connections to this cable. The cable is generally prepared by removing a portion of the outer dielectric and inner dielectric to expose a suitable length of the center conductor, generally about a quarter to a half an inch, with an exposure of the outer dielectric to permit connection to the foil or braiding layer of the cable. Suitable coaxial cable connectors and methods of preparing the cable are illustrated in US 4,834,675; 4,583,81 1 ; 5,127,853 and 5,277,598. The cable preparation of Raychem's EZF® connector and that disclosed in 4,583,811 is preferred. The disclosures of each of these patents is completely incorporated herein by reference for all purposes. These patents illustrate suitable methods of preparing the cable and various types of coaxial cable connectors.

When coaxial cable connectors are used in an outdoor or other harsh environments, a sealing sleeve or other items are often included along with the cable. An example of a sealing sleeve is illustrated in US 4,674,818, the complete disclosure of which is incorporated completely herein by reference for all purposes.

Although these cables can terminate to a coaxial cable, a connector which integrates the functions of sealing and termination would be highly desirable. In addition, having a connector which provides for a security feature, such that the connector cannot be removed in the absence of a standard design but special tool, would be additionally desirable.

Summary of the Invention

The invention provides for all the previously desirable features as well as many others which would be obvious to the ordinary skilled artisan. The connector is straightforward to install by the craftsperson and the act of installation provides a seal between the connector and the cable splice or cable tap.

The connector provides a built in interfacial seal which is preinstalled on the connector. The act of installing the connector automatically affects the seal between the tap port and/or the cable splice and the front portion of the connector. A separate seal also occurs between the connector and the cable jacket upon installation. Additionally the shell and mandrel interface may optionally be designed so that the connector is a low insertion force/high retention force connector. The advantages of this connector are its integral front seal cannot be forgotten by the operator. The act of installing the connector actuates deploys and affects the seal at the port and cable ends of the connector.

Additionally, installing the connector deploys a cable retention ring which traps the cable jacket and the braid and exerts radial pressure over the cable jacket directly over the mandrel tube. This prevents the braid to mandrel interface from being disturbed after the final installation even during subsequent unmatting and matting cycles. Furthermore the act of installing the connector actuates and deploys and affects the rear seal which is driven over the mandrel. This prevents the seal pressure from relaxing over time (time invarient cable connector seal) due to cable dielectric compression set and maintains a more reliable seal between the connector and cable jacket. Additional benefits are the low shell installation forces about 20 lbs. pressure coupled with high shell retention forces about 50 lbs. pressure, which provides a high security connection system. In particularly preferred embodiments a standard design but special tool is need to remove the shell. Brief Description of the Drawingfe )

Figure 1 illustrates an embodiment of the coaxial cable connector of the present invention. Figure 2 illustrates an exploded view of the connector of figure 1.

Figure 3a through 3c illustrate the installation process of the connector of Figures 1 and 2.

Description of the Preferred Embodiments

The preferred embodiments of the invention will be illustrated in Figures 1 and 2. More specifically, the push-on/pull-off connector in both the partial cross section and exploded view is illustrated as connector 100.

The connector includes a metallic mandrel body 10. The mandrel 10 includes a portion 10a which is secured to the coaxial cable between the inner dielectric layer and the outer shielding and dielectric layers. The portion of the mandrel opposite thereto illustrated as 10b fits on the cable splice or cable tap port. The mandrel 10 also includes a section 10c which is a circumferential groove to permit the attaching of the sealing grommet 20 thereto as well as a stop point for the bail 12 upon the installation of the connector. In cross-section this appears as a detent. Preferred grommets are elastomeric plastics or rubbers such as silicone rubber, butadiene rubber, and the like.

Th bail 12 is fabricated from a suitable spring material such as a spring metal such that it provides hoop stress around the cable while permitting the outer shell 16 to rotate freely therearound. The bail includes a plurality of fingers. Although four fingers are illustrated, any suitable number can be from 2 to 10. Three or four fingers are preferred. The bail contains a peaked portion 12b which seats in the detent 16a (circumferential groove) upon the installation of the cable and provides positive feedback of the installation for the connector for the installer. The bail also contains an end portion 12 which positively engages the cable splice or cable tap port under positive spring pressure, when the connector is installed onto the splice or port. Feedback is also provided when end portion 12a seats in the detent (circumferential groove) 10c upon installation. The outer shell 16 includes a suitable ring seal 18 such as an "O" ring seal and an cable locking ring 14 which grips the cable between the outer shell 16 and the mandrel portion 10a upon the installation of the cable. Preferred "O" rings are silicone elastomer rubber "O" rings. After installation, the shell 16 is rotatable about the connector while the bail 12 at ridge 12b seats in detent 16a in shell 16 giving further positive feedback of the installation. The locking shell can be any suitable material but a low stress relaxing and low creep plastics are preferred. A soft brass or combinations of plastics and metals can also be used.

Standard cable preparation techniques and tools are used to install the connector 100. This includes cutting away the inner and outer dielectric and outer shielding to expose the center conductor. Thereafter a portion of the outer dielectric is removed and the foil or braid may be folded back. Examples of cable preparation are described US 4,583,811 and EZF® connector product brochures. The connector may be packaged in a cassette such as EZF® connecter cassette or the cassettes described in US 4,639,068, the disclosure of which is completely incorporation herein by reference for all purposes. The standard EZF® type cassette is preferred.

The prepared cable is inserted through the back end opening 16c of the shell 16. The shell 16 is moved back along the cable. Thereafter the cable is urged onto the mandrel 10 and through the opening in the bail 12. When the cable is fitted onto the mandrel 10, the connector is removed from the cassette and put onto the splice or tab port. Finally the shell 16 is slid along the cable and over the bail 12 and mandrel 10. The locking ring 14 traps the outer dielectric and shielding layer between the mandrel 10 and the bail 12.

As the shell moves forward the sealing grommet 20 is compressed under the shell 16 and into a compressive seal with the splice or tap port threads and optionally and preferably the face plate of the splice or tap port. The seal 18 is also sealing compressed between the shell 16 and the locking shell 14 for additional sealing and strain relief. The action of the locking shell 14 abutting the bail 12 after 12a seats in groove 10c forces ridge 12b outward to tightly engage shell 16 at detent groove 16a. This explains in part the higher removal force necessary to overcome this gripping for removal. For removal a tool fits in circumferential groove (detent) 16c and abuts the splice or tap port to exert the higher force needed to remove the connector, i.e. the tool gives mechanical leverage for removal.

The process of installation of the connector 100 to a cable 400 and tap port 500 is illustrated inf figures 3a, 3b, and 3c. The cable 400 has the center conductor 410, inner dielectric 420, outer shielding 430, and outer dielectric 440. The shell 16 is placed on the prepared cable and then urges the locking ring 14 out of the shell 16 to abut the bail 12 as the connector is placed on the port 500. When in contact with the port 500 the shell 18 is urged forward the compress bail 12 at 12b into the detent 16a and also seals 20 and 18 to effect the installed sealed system. Of course, an indoor connector could dispense with either seal 18 or seal 20 or both.

While the invention has been described with respect to particularly preferred embodiments, modifications which would be obvious to the ordinary skilled artisan are contemplated to be within the scope of the invention. For example, the cable end portion 10a of the mandrel could have a helical knife edge instead of the circular knife edge barb illustrated. Thus, the full equivalence are contemplated to be within the scope of the invention.

Claims

ClaimsWhat is claimed is:

1. A coaxial cable connector which comprises:

a mandrel body capable of fitting on to a coaxial cable between the inner dielectric and the outer shielding and dielectric layers, said mandrel including a region for inserting between the outer shielding and dielectric and the inner dielectric and a region opposite thereto having a lip to seat a sealing grommet and a clasping bail,

a clasping bail which seats to the mandrel upon the connector installation, and

an outer shell which includes a shell body, a back end seal portion of the body, and a cable locking ring which secures the outer dielectric and inner dielectric between the cable locking ring and the mandrel,

2. The connector according to claim 1 wherein the bail is made of a spring metal.

3. The connector according to claims 1 or 2 further including a sealing grommet to seal to the splice or tap port.

4. The connector according to claim 3 wherein the sealing grommet is a material selected from the group consisting of elastomeric plastics, elastomeric rubbers, or mixtures thereof.

5. The connector according to any preceeding claim wherein the shell includes a seal for the portion of the connector away from the grommet seal which seals to the outer dielectric of the cable;

6. The connector according to any preceeding claim wherein the shell seal in an "O" ring seal.

7. The connector according to any preceeding claim wherein the shell freely rotates about the cable securing means and the bail.

8. The cable connector according to any preceeding claim wherein the outer shell includes a circumferential detent therein for the seating of the bail upon installation of the connector and the mandrel includes a portion to seat the bail such that tactile response is given to the installer upon the installation of the cable.

9. The cable connector according to any preceeding claim wherein the outer shell includes a circumferential detent therein for the seating of the bail upon installation of the connector and the mandrel includes a portion to seat the bail such that tactile response is given to the installer upon the installation of the cable.

10. The connector according to any preceeding claim further including a sealing grommet to seal to the splice or tap port.

11. The connector according to any preceeding claim wherein the bail has from two to ten fingers.

12. The connector according to any preceeding claim wherein the mandrel has a knife edge of at least one revolution.

13. The connector according to any preceeding claim wherein the installation force is about 20 lbs ± 5 lbs and the removal force is 50 lbs ± 5 lbs.

14. The connector according to any preceeding claim wherein the locking shell is fabricated from plastic, metal, or combinations thereof.