Electrical connectors – Including or for use with coaxial cable
Reexamination Certificate
2000-06-21
2001-04-17
Sircus, Brian (Department: 2839)
Electrical connectors
Including or for use with coaxial cable
Reexamination Certificate
active
06217383
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to connectors for electrically connecting a coaxial cable to a threaded port.
2. Prior Art
The design and construction of F-type coaxial cable connectors, such as those commonly used for transmitting cable TV signals, digital data lines and home satellite systems, has changed in recent years in order to comply with changing industry standards and FCC regulations. Currently, connectors must exhibit a low RF leakage level, even in exposed environments. A moisture-proof seal between the connector and the conductor(s) within a coaxial cable is essential to prevent corrosion and RF leakage.
Connectors adapted to form a secure, electrically conductive connection between a coaxial cable and a threaded female port have been developed. Such prior art connectors are discussed, for example, in U.S. Pat. Nos. 5,024,605 to Ming-Hua, 4,280,749 to Hemmer, 4,593,964 to Forney, Jr. et al., 5,007,861 to Stirling, 5,073,129 to Szegda and 5,651,699 to Holliday. U.S. Pat. No. 5,879,191 to Burris, discusses prior art efforts to provide a coaxial connector which is moisture-proof and minimizes radiative loss of signal from the cable. A radial compression type of coaxial cable connector of the type generally used today, is described in detail in U.S. Pat. No. 5,632,651 to Szegda, and the disclosure of Szegda '651 relating to radial compression coaxial cable connectors is incorporated herein by reference thereto.
While the innovative plethora of prior art connectors, some of which are disclosed above, provide improved moisture sealing and/or RF leakage characteristics, all have inherent limitations. For example, the integrity of the attachment between the cable and connector is “craft sensitive”, depending on the skill of the installer. The steps required in order to provide a secure, sealing engagement between a connector and a coaxial cable include opportunities for installation errors to occur. Installation of a coaxial cable connector on a coaxial cable requires that the end of the cable first be prepared to receive the connector. The connector is then manually forced onto the prepared end of the cable until the protective jacket and underlying conductive braid of the cable are separated from the dielectric core of the cable. The cable is further advanced into the connector by hand, which requires the application of substantial force by the installer, until the correct depth of insertion is attained. Finally, the connector is securely affixed to the cable by compressing the connector, again by hand, with a compression tool. With most prior art connectors, during the compression step, the cable jacket and conductive braid are compressed against an annular barb disposed on the surface of an underlying tubular shank during the final several millimeters of compressive travel. If the installer fails to completely compress the connector, especially in the final 20 percent of the compressive range, the connector may come loose. Incorrect installation will result in unacceptable levels of RF leakage.
Prior art connectors rely on a single point of compression (i.e., between the annular barb on the tubular shank and the body portion of the connector) for secure attachment to a coaxial cable. Accordingly, the barb on the tubular shank has a relatively high profile or angular pitch, which high profile makes it difficult to force the prepared end of a coaxial cable into the connector. A connector having a single point of compression requires the cable to have a jacket thickness lying within a small range of tolerances. Recent developments in building codes require that coaxial cable installed in particular locations within a structure, such as plenum areas, air return ducts and elevator shafts, have fire retardent jacketing materials. Such new jacketing materials have different physical properties than the standard coaxial cables previously used, such as elasticity, smoothness and thickness, which renders prior art connectors less than optimal for use therewith. The skilled artisan will appreciate that it would be an advancement in the art to provide a cable connector wherein the annular barb on the tubular shank has a relatively low profile, enabling the connector to accommodate the facile insertion of coaxial cable having a variety of thicknesses, elasticity and/or smoothness, and be securely attached to the cable. Accordingly, there remains a need for a cable connector that is impermeable to moisture, can be used with a variety of cable jacket and braid thicknesses and is easy to install with minimum chance for error.
SUMMARY
It is a first object of the invention to provide a coaxial cable connector that is resistant to the ingress of moisture.
It is a further object of the invention to provide a coaxial cable connector that may be easily inserted over the prepared end of a coaxial connector with a minimum amount of force.
It is yet another object of the invention to provide a coaxial cable connector that meets the above-stated objectives and is of integral construction, having no separable parts.
It is still another object of the invention to provide a coaxial cable connector that can be securely attached to a variety of coaxial cables having a broad range of jacket thicknesses.
The present invention provides a compression-type coaxial cable connector meeting the objectives of the invention. The connector, in accordance with the present invention, is of integral construction and includes a nut, a tubular shank, a slotted body portion, two “O” rings and a compression sleeve. The nut, as with all of the elements comprising the connector, has an axial conduit therethrough, the nut conduit having a threaded forward end with a first diameter and a trailing end having a second diameter that is less than the first diameter. A first “O” ring having an outer diameter substantially equal to the first diameter, is disposed within the axial conduit of the nut forward of and adjacent the trailing end. The tubular shank is an elongate, generally cylindrical tube having a leading end with a flange thereon, and a trailing end. The flange is disposed within the conduit of the nut forward of the first “O” ring, with the trailing end, which includes an annular barb disposed circumfrentially thereon, projecting rearwardly through the trailing end of the axial conduit within the nut.
The slotted body portion acts cooperatively with the compression sleeve to provide two points of radial compression of the outer jacket and conductive braid of the cable; a first point being disposed between the slotted body portion and the tubular shank, and a second point disposed between the compression sleeve and the barb on the tubular shank as will be discussed below. The slotted body portion is a substantially cylindrical member having a leading end, a trailing end and an axial conduit coextensive with the length thereof. The diameter of the conduit within the slotted body portion is stepped, having a smaller diameter in the leading end than in the trailing end. The trailing end of the conduit wall is slotted longitudinally and has a plurality of annular gripping ridges thereon. The leading end of the slotted body portion is compression fitted to an annular shoulder on the tubular shank, the shoulder being disposed rearward of the trailing end of the nut, to concentrically overlie the tubular shank. A trailing portion of the tubular shank extends rearwardly from the trailing end of the slotted body portion, the extended portion including the relatively low profile annular barb disposed near the trailing end of the tubular shank.
As mentioned above, the tubular shank includes a shoulder adjacent the leading end thereof disposed rearward of the flange. When the stepped inner diameter of the leading end of the conduit within the slotted body portion is compression fitted to the shoulder on the tubular shank, the slotted body portion is prevented from moving with respect to the tubular shank and the nut is rotatably mounted on, and locked to, the tubular s
Holland Michael
Min-Hua Yeh
Dinh Phuong KT
Holland Electronics, LLC
Petit Michael G.
Sircus Brian
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