Abstract:
Axially compressible, self-sealing, high bandwidth F-connectors for conventional hand tools for interconnection with coaxial cable. An internal, dual segment sealing grommet activated by compression elongates and deforms to provide a travelling seal. Each connector has a rigid nut that is rotatably secured to a, tubular body. A rigid, conductive post has a barbless shank that coaxially extends through the connector and penetrates the coaxial cable within the connector. A tubular, metallic end cap is slidably fitted to a body shank, and is thereafter forcibly compressed lengthwise during installation. The end cap has a ring groove for seating the enhanced grommet. The end cap can irreversibly assume any position, being held by end cap teeth. The grommet travels and extrudes during compression to mate and intermingle with a portion of the cable braid that is looped back to form a prepared cable end.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This is a Continuation-in-Part application based upon a prior U.S. utility patent application entitled “Sealed Compression Type Coaxial Cable F-Connectors,” filed Feb. 26, 2009 now U.S. Pat. No. 7,841,896, Ser. No. 12/380,327, which was a Continuation-in-Part of an application entitled “Compression Type Coaxial Cable F-Connectors,” Ser. No. 12/002,261, filed Dec. 17, 2007, now U.S. Pat. No. 7,513,795, issued Apr. 7, 2009. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to electrical connectors for coaxial cables and related electrical fittings. More particularly, the present invention relates to coaxial F-connectors of the axial compression type which are adapted to be installed with hand compression tools, and specifically to F connectors that are internally sealed when compressed. Known prior art of relevance is classified in U.S. patent No. Class 439, Subclasses 349, 583, and 584. 
     2. Description of the Related Art 
     A variety of coaxial cable connectors have been developed in the electronic arts for interfacing coaxial cable with various fittings. Famous older designs that are well known in the art, such as the Amphenol PL-259 plug, require soldering and the hand manipulation of certain components during installation. One advantage of the venerable PL-259 includes the adaptability for both coaxial cables of relatively small diameter, such as RG-59U or RG-58U, and large diameter coaxial cable (i.e., such as RG-8U, RG-9U, LMR-400 etc.). So-called N-connectors also require soldering, but exhibit high frequency advantages. Numerous known connectors are ideal for smaller diameter coaxial cable, such as RG-58U and RG-59U. Examples of the latter include the venerable “RCA connector”, which also requires soldering, and the well known “BNC connector”, famous for its “bayonet connection”, that also requires soldering with some designs. 
     Conventional coaxial cables typically comprise a solid or stranded center conductor surrounded by a plastic, dielectric insulator and a coaxial shield of braided copper and foil. An outer layer of insulation, usually black in color, coaxially surrounds the cable. To prepare coaxial cable for connector installation, a small length of the jacket is removed, exposing a portion of the outer conductive shield that is drawn back and coaxially positioned. A portion of the insulated center is stripped so that an exposed portion of the inner copper conductor can become the male prong of the assembled F-connector. Experienced installers are well versed in the requirements for making a “prepared end” of a coaxial line for subsequent attachment to a compression F-connector. 
     The modern F-type coaxial cable connector has surpassed all other coaxial connector types in volume. These connectors are typically used in conjunction with smaller diameter coaxial cable, particularly RG-6 cable and the like. The demand for home and business wiring of cable TV system, home satellite systems, and satellite receiving antenna installations has greatly accelerated the use of low-power F-connectors. Typical F-connectors comprise multiple pieces. Typically, a threaded, hex-head nut screws into a suitable socket commonly installed on conventional electronic devices such as televisions, satellite receivers and accessories, satellite radios, and computer components and peripherals. The connector body mounts an inner, generally cylindrical post that extends coaxially rearwardly from the hex nut. Usually the post is barbed. 
     When a prepared end of the coaxial cable is inserted, the post penetrates the cable, sandwiching itself between the insulated cable center and the outer conductive braid. A deflectable, rear locking part secures the cable within the body of the connector after compression. The locking part is known by various terms in the art, including “cap”, or “bell” or “collar” or “end sleeve” and the like. The end cap, which may be formed of metal or a resilient plastic, is compressed over or within the connector body to complete the connection. A seal is internally established by one or more O-rings or grommets. Suitable grommets may comprise silicone elastomer. 
     The design of modern F-connectors is advantageous. First, typical assembly and installation of many F-connector designs is completely solderless. As a result, installation speed increases. Further, typical F-connectors are designed to insure good electrical contact between components. The outer conductive braid for the coaxial cable, for example, is received within the F-connector, and frictional and/or compressive contact insures electrical continuity. For satellite and cable installations the desired F-connector design mechanically routes the inner, copper conductor of the coaxial cable through the connector body and coaxially out through the mouth of the connector nut to electrically function as the male portion of the connector junction without a separate part. 
     An important F-connector design innovation relates to the “compression-type” F-connector. Such designs typically comprise a metallic body pivoted to a hex-head nut for electrical and mechanical interconnection with a suitably threaded socket. A rigid, conductive post is coaxially disposed within the connector body, and is adapted to contact the conductive outer braid of the coaxial cable when the prepared cable end is installed. After insertion of the stripped end of the coax, the rear connector cap or collar is forcibly, axially compressed relative to the connector body. A suitable hand operated compression tool designed for compression F-connectors is desirable. Some connector designs have an end cap adapted to externally mount the body, and some designs use a rear cap that internally engages the F-connector body. In some designs the cap is metal, and in others it is plastic. In any event, after the cap is compressed, the braided shield in electrically connected and mechanically secured, and a tip of the exposed copper center conductor properly extends from the connector front. The conductive metallic coaxial cable braid compressively abuts internal metal components, such as the post, to insure proper electrical connections. 
     One popular modern trend with compression F-connectors involves their preassembly and packaging. In some preassembled designs the rear sleeve (i.e., or end cap, collar etc.) is compressively forced part-way unto or into the connector body prior to bulk packaging. The end sleeve is pre-connected to the connector end by the manufacturer to ease the job of the installer by minimizing or avoiding installation assembly steps. For example, when the installer reaches into his or her package of connectors, he or she need draw out only one part, or connector, and need not sort connector bodies from connector end caps or sleeves and assemble them in the field, since the device end cap is already positioned by the manufacturer. Because of the latter factors, installation speed is increased, and component complexity is reduced. 
     Typically, preassembled compression F-connector designs involve locking “detents” that establish two substantially fixed positions for the end cap along the length of the connector body. The cap, for example, may be provided with an internal lip that surmounts one or more annular ridges or grooves defined on the connector collar for the mechanical detent. In the first detent position, for example, the end cap yieldably assumes a first semi-fixed position coupled to the lip on the connector end, where it semi-permanently remains until use and installation. The connection force is sufficient to yieldably maintain the end cap in place as the F-connectors are manipulated and jostled about. During assembly, once a prepared cable end is forced through the connector and its end cap, the connector is placed within a preconfigured void within and between the jaws of a hand-operated compression installation tool, the handles of which can be squeezed to force the connector parts together. During compression, in detented designs, the end cap will be axially forced from the first detent position to a second, compressed and “installed” detent position. 
     High quality F-connectors are subject to demanding standards and requirements. Modern home satellite systems distribute an extremely wide band signal, and as the demand for high definition television signals increases, and as more and more channels are added, the bandwidth requirements are becoming even more demanding. At present, a goal in the industry is for F-connectors to reliably handle bandwidths approximating three to four GHz. 
     Disadvantages with prior art coaxial F-connectors are recognized. For example, moisture and humidity can interfere with electrical contact, degrading the signal pathway between the coax, the connector, and the fitting to which it is connected. For example, F-connectors use compression and friction to establish a good electrical connection between the braided shield of the coaxial cable and the connector body, as there is no soldering. Moisture infiltration, usually between the connector body and portions of the coaxial cable, can be detrimental. Signal degradation, impedance mismatching, and signal loss can increase over time with subsequent corrosion. Moisture infiltration often increases in response to mechanical imperfections resulting where coaxial compression connectors are improperly compressed. 
     Mechanical flaws caused by improper crimping or compression can also degrade the impedance or characteristic bandwidth of the connector, attenuating and degrading the required wide-band signal that modern TV satellite dish type receiving systems employ. If the axial compression step does not positively lock the end cap in a proper coaxial position, the end cap can shift and the integrity of the connection can suffer. Furthermore, particularly in modern, high-bandwidth, high-frequency applications involved with modern satellite applications distributing multiple high definition television channels, it is thought that radial deformation of internal coaxial parts, which is a natural consequence of radial compression F-connectors, potentially degrades performance. 
     Dealers and installers of satellite television equipment have created a substantial demand for stripping and installation tools for modern compression type F-connectors. However, installers typically minimize the weight and quantity of tools and connectors they carry on the job. There are a variety of differently sized and configured F-connectors, and a variety of different compression tools for installation. 
     On the one hand, F-connectors share the same basic shape and dimensions, as their connecting nut must mate with a standard thread, and the internal diameter of critical parts must accommodate standard coaxial cable. On the other hand, some compression F connectors jam the end sleeve or cap into the body, and some force it externally. Some connectors use a detent system, as mentioned above, to yieldably hold the end sleeve or cap in at least a first temporary position. Still other connectors require manual assembly of the end cap to the body of the connector. In other words, size differences exist in the field between the dimensions of different F-connectors, and the tools used to install them. 
     The typical installer carries as few tools as practicable while on the job. He or she may possess numerous different types of connectors. Particularly with the popularity of the “detented” type of compression F-connector, hand tools customized for specific connector dimensions have arisen. The internal compression volume of the hand tool must match very specific “before” and “after” dimensions of the connector for a precision fit. After a given compression F-connector is preassembled, then penetrated by the prepared end of a segment of coaxial cable, the tool must receive and properly “capture” the connector. The most popular compression tools are known as “saddle” types, or “fully enclosed” types. In either event the tool must be sized to comfortably receive and “capture” connectors of predetermined external dimensions. Tools are designed for proper compression deflection, so the connector assumes a correct, reduced length after compression. Popular tools known in the art are available from the Ripley Company, model ‘Universal FX’, the ‘LCCT-1’ made by International Communications, or the ICM ‘VT200’ made by the PPC Company. 
     Connector failures often result from small mechanical misalignments that result where the internal compression volume of the installation tool does not properly match the size of the captured connector. The degree of internal tool compression should closely correlate with the reduced length of the connector after axial deflection. In other words, the end sleeve or cap must be forcibly displaced a correct distance. Wear and tear over time can mismatch components. In other words, where hand tools designed for a specific connector length are used with connectors of slightly varying sizes, as would be encountered with different types or brands of connectors, improper and incomplete closure may result. Misdirected compression forces exerted upon the end cap or sleeve and the connector body or during compression can cause deformation and interfere with alignment. The asymmetric forces applied by a worn or mismatched saddle type compression tool can be particularly detrimental. Sometimes improper contact with internal grommets or O-rings results, affecting the moisture seal. 
     The chance that a given compression hand tool, used by a given installer, will mismatch the particular connectors in use at a given time is often increased when the connectors are of the “detent” type. Detented compression connectors, examples of which are discussed below, are designed to assume a predetermined length after both preassembly, and assembly. Thus detented F-connectors require a substantially mating compression tool of critical dimensions for proper performance. The chances that a given installer will install the requested compression F-connectors involved at a given job, or specified in a given installation contract, with the correctly sized, mating installation tool are less than perfect in reality. Another problem is that detented F-connector, even if sized correctly and matched with the correct installation tool, may not install properly unless the installer always exerts the right force by fully deflecting the tool handles. Even if a given installation tool is designed for the precise dimensions of the connectors chosen for a given job, wear and tear over the life of the hand tool can degrade its working dimensions and tolerances. Real world variables like these can conclude with an incorrectly installed connector that does not reach its intended or predetermined length after assembly. 
     If and when the chosen compression tool is not correctly matched to the F-connector, deformation and damage can occur during installation, particularly with detented compression F-connectors. Another problem occurs where an installer improperly positions the connector within the hand tool. Experienced installers, who may have configured and installed thousands of F-connectors over the years, often rely upon a combination of “look” and “feel” during installation when fitting connectors to the cable, and when positioning the connectors in the hand tool. Repetition and lack of attention tends to breed sloppiness and carelessness. Improper alignment and connector placement that can cause axial deformation. Sloppiness in preparing a cable end for the connector can also be detrimental. 
     A modern, compression type F-connector of the compression type is illustrated in U.S. Pat. No. 4,834,675 issued May 30, 1989 and entitled “Snap-n-seal Coaxial Connector.” The connector has an annular compression sleeve, an annular collar which peripherally engages the jacket of a coaxial cable, an internal post coaxially disposed within the collar that engages the cable shield, and a rotatable nut at the front for connection. A displaceable rear cap is frangibly attached to the body front, and must be broken away for connector installation manually and then pre-positioned by the user on the connector end. The end cap is axially forced into coaxial engagement within the tubular compression sleeve between the jacket of the coaxial cable and the annular collar, establishing mechanical and electrical engagement between the connector body and the coaxial cable shield. 
     U.S. Pat. No. 5,632,651 issued May 27, 1997 and entitled “Radial compression type Coaxial Cable end Connector” shows a compression type coaxial cable end connector with an internal tubular inner post and an outer collar that cooperates in a radially spaced relationship with the inner post to define an annular chamber with a rear opening. A threaded head attaches the connector to a system component. A tubular locking cap protruding axially into the annular chamber through its rear is detented to the connector body and is displaceable axially between an open position accommodating insertion of the tubular inner post into a prepared cable end, with an annular outer portion of the cable being received in the annular chamber, and a clamped position fixing the annular cable portion within the chamber. 
     Similarly, U.S. Pat. No. 6,767,247 issued Jul. 27, 2004 depicts a compression F-connector of the detent type. A detachable rear cap or end sleeve temporarily snap fits or detents to a first yieldable position on the connector rear. This facilitates handling by the installer. The detachable end sleeve coaxially, penetrates the connector body when installed, and the coaxial cable shield is compressed between the internal connector post and the end sleeve. 
     U.S. Pat. No. 6,530,807 issued Mar. 11, 2003, and entitled “Coaxial connector having detachable Locking Sleeve,” illustrates another modern compression F-connector. The connector includes a locking end cap provided in detachable, re-attachable snap engagement within the rear end of the connector body for securing the cable. The cable may be terminated to the connector by inserting the cable into the locking sleeve or the locking sleeve may be detachably removed from the connector body and the cable inserted directly into the cable body with the locking sleeve detached subsequently. 
     U.S. Pat. No. 5,470,257 issued Nov. 28, 1995 shows a detented, compression type coaxial cable connector. A tubular inner post is surrounded by an outer collar and linked to a hex head. The radially spaced relationship between the post and the collar defines an annular chamber into which a tubular locking cap protrudes, being detented in a first position that retains it attached to the connector. After the tubular inner post receives a prepared cable end, the shield locates within the annular chamber, and compression of the locking cap frictionally binds the parts together. 
     U.S. Pat. No. 6,153,830 issued Nov. 28, 2000 shows a compression F-connector with an internal post member, and a rear end cap that coaxially mounts over the cable collar or intermediate body portion. The internal, annular cavity coaxially formed between the post and the connector body is occupied by the outer conductive braid of the coaxial cable. The fastener member, in a pre-installed first configuration is movably fastened onto the connector body. The fastener member can be moved toward the nut into a second configuration in which the fastener member coacts with the connector body so that the connector sealingly grips the coaxial cable. U.S. Pat. No. 6,558,194 issued May 6, 2003 and entitled “Connector and method of Operation” and U.S. Pat. No. 6,780,052 issued Aug. 24, 2004 are similar. 
     U.S. Pat. No. 6,848,940 issued Feb. 1, 2005 shows a compression F-connector similar to the foregoing, but the compressible end cap coaxially mounts on the outside of the body. 
     Another detented compression F-connector is discussed in U.S. Pat. No. 6,848,940, issued Feb. 1, 2005 and entitled “Connector and method of Operation.” The connector body coaxially houses an internal post that is coupled to the inner conductor of a coaxial cable. A nut is coupled to either the connector body or the post for the connecting to a device. The post has a cavity that accepts the center conductor and insulator core of a coaxial cable. The annulus between the connector body and the post locates the coaxial cable braid. The end cap or sleeve assumes a pre-installed first configuration temporarily but movably fastened to the connector body, a position assumed prior to compression and installation. The end cap can be axially forced toward the nut into an installed or compressed configuration in which it grips the coaxial cable. 
     Various hand tools that can crimp or compress F-connectors are known. 
     For example, U.S. Pat. No. 5,647,119 issued Jul. 15, 1997 and entitled “Cable terminating Tool” discloses a hand tool for compression type F-connectors. Pistol grip handles are pivotally displaceable. A pair of cable retainers pivotally supported on a tool holder carried by one of the handles releasably retains the cable end and a preattached connector in coaxial alignment with an axially moveable plunger. The plunger axially compresses the connector in response to handle deflection. The plunger is adjustable to adapt the tool to apply compression type connector fittings produced by various connector manufactures. 
     Another example is U.S. Pat. No. 6,708,396 issued Mar. 23, 2004 that discloses a hand-held tool for compressively installing F-connectors on coaxial cable. An elongated body has an end stop and a plunger controlled by a lever arm which forcibly, axially advances the plunger toward and away from the end stop to radially compress a portion of the connector into firm crimping engagement with the end of the coaxial cable. 
     Similarly, U.S. Pat. No. 6,293,004 issued Sep. 25, 2001 entitled “Lengthwise compliant crimping Tool” includes an elongated body and a lever arm which is pivoted at one end to the body to actuate a plunger having a die portion into which a coaxial cable end can be inserted. When the lever arm is squeezed, resulting axial plunger movements force a preassembled crimping ring on each connector to radially compress each connector into sealed engagement with the cable end, the biasing member will compensate for differences in length of said connectors. 
     Despite numerous attempts to improve F-connectors, as evidenced in part by the large number of existing patents related to such connectors, a substantial problem with internal sealing still exists. It is important to prevent the entrance of moisture or dust and debris after the connector is installed. To avoid degradation in the direct current signal path established through the installed connector&#39;s metal parts, and the radio frequency, VHF, UHF and SHF signal paths and characteristics, a viable seal is required. Connectors are commonly used with coaxial cables of several moderately different outside diameters. For example, common RG-59 or RG-59/U coaxial cable has a different diameter than RG-6 or RG-6/U coaxial cable. Some cables have differently sized outer jackets and other internal differences that may not be readily apparent to the human eye. One way to promote sealing is through internal grommets or seals that are deflected and deformed when the fitting is compressively deployed to tightly encircle the captivated coaxial cable. 
     For example, U.S. Pat. No. 3,678,446 issued to Siebelist on Jul. 18, 1972 discloses an analogous coaxial connector for coaxial cables which have different sizes and structural details. An internal, coaxial sealing band is utilized for grasping the coaxial cable when the connector parts are secured together. Other examples of connectors or analogous electrical fittings with internal sealing grommets include U.S. Pat. Nos. 3,199,061, 3,375,485, 3,668,612, 3,671,926, 3,846,738, 3,879,102, 3,976,352, 3,986,737, 4,648,684, 5,342,096, 4,698,028, 6,767,248, 6,805,584, 7,118,416, and 7,364,462. Also pertinent are foreign references WO/1999065117, WO/1999065118, WO/2003096484 and WO/2005083845. 
     The sealing problem associated with compressive F-connectors discussed above, however, remains a difficult problem to overcome and is a focus of this invention. Moreover, during experiments with compression F-connectors of the type discussed above, it has been suggested that the conventional barbed post utilized in many designs creates signal discontinuities and degrades bandwidth. For example, the conical geometry of the barbs necessitates that such posts vary in diameter. It is thought that at extremely high frequencies this creates passive intermodulation. Barbed posts with barbs varying in diameter from their shank can create abutting resonate cavities at very high frequencies. As a result, the achievable signal bandwidth is reduced with barbed posts. At the same time, the absence of barbed post structure might suggest that the fitting integrity of axially compressed connectors is compromised. The seal design of our invention is designed, in part, to ameliorate the latter potential problem. 
     BRIEF SUMMARY OF THE INVENTION 
     This invention provides improved, axial compression type F-connectors designed to be quickly and reliably connected to coaxial cable of varying diameters and structures. The new F-connectors establish a high operating bandwidth and create reliable internal seals. 
     Each connector has a rigid, metallic hex-headed nut for threadable attachment to conventional threaded sockets. An elongated, preferably molded plastic body is rotatably and axially coupled to the nut. A rigid, conductive post coaxially extends through the nut and the tubular body, captivating the nut with an internal flange. The elongated tubular post shank penetrates and receive an end of prepared coaxial cable fitted to the F-connector. A rigid, preferably metallic end cap is slidably fitted to the body, and thereafter forcibly compressed along the length of the body shank for installation. Preferably the post is not barbed. 
     Preferably the tubular body has a generally cylindrical stop ring that is integral and coaxial with a reduced diameter shank. The elongated outer periphery of the body&#39;s shank is smooth and free of obstacles. No detented structure is formed upon or machined into the external shank surface. The end cap has a tubular portion that externally, coaxially mounts the body shank, and which can be axially compressed relative to the body, such that the end cap and body are telescoped relative to one another. The end cap smoothly, frictionally grips the shank of the body, and it may be positioned at any point upon the shank as desired. However, maximum displacement in response to compression is limited by the integral stop ring axially adjoining the shank. 
     Preferably the open mouth of the end cap has a plurality of radial “teeth” that firmly grasp the body shank. When the end cap is slidably telescoped upon the body shank, the teeth grasp the shank for a reliable mechanical connection without radially compressing or deforming the connector body. The end cap may assume any position along the length of body shank between the annular rear end of the body and the annular stop ring face. Cable is restrained within the connector by an internal jam point that resists axial withdrawal of the cable end. 
     In the best mode a special “traveling seal” is established. To accommodate cables of different sizes and types and diameters, a special sealing grommet is disposed within the connector, preferably seated within the end cap. The enhanced sealing grommet, resembling an O-ring, comprises two primary portions that are integral and coaxial. The outermost portion (i.e., the outer diameter) of the preferred seal is of a generally rectangular cross section, adapted to snugly, coaxially seat within the end cap rear. An integral, inner nose portion of the grommet projects inwardly towards the fitting front. The leading edge of the bulbous nose portion is convex. When the fitting is compressed about a prepared coaxial cable end, the tapered shank of the fitting body contacts the grommet above the nose portion and deflects and deforms the grommet. During installation, a travelling phenomena occurs wherein the grommet is deformed radially and axially, such that the body is squeezed into the interior annulus between the body shank and the coaxial cable prepared end overlying the post. Portions of the grommet are forced longitudinally into contact with the coaxial cable sheath, being compressed into interstitial regions of the wire mesh comprising the cable sheath. Seal deformation is facilitated by the barbless construction of the post. The deformed grommet thus provides a seal against moisture, dust, debris and the elements. 
     Thus a basic object is to provide an improved, compression type electrical connector suitable for satellite and cable television systems, that generates an improved seal when the fitting is installed. 
     Another basic object is to provide an improved compression-type F-connector that can be reliably used with a variety of different installation tools and with a variety of different cables. 
     It is also an object to provide a compression type F-connector of the character described that facilitates a proper “capture” by various compression installation tools. 
     It is also an important object to provide a compression type F-connector of the type disclosed that reliably provides a good electrical connection path between the threaded nut, the internal post, and the coaxial cable to which the connector is fitted. 
     A still further object is to provide a connector suitable for use with demanding large, bandwidth systems approximating four GHz. It is a feature of our invention that a barbless post is preferably utilized, and bandwidth is enhanced by eliminating resonant cavities. 
     A related object is to provide an F-connector ideally adapted for home satellite systems distributing multiple high definition television channels. 
     Another important object is the F-connector has been adapted for use in wideband RF applications. 
     Another important object is to provide a connector of the character described that includes an improved sealing grommet for enhancing the required weatherproof and moisture resistant characteristics of the fitting. 
     Another important object is to provide a compression F-connector of the character described that can be safely and properly installed without deformation of critical parts during final compression. 
     A related object is to provide a connector of the character described that reliably functions even when exposed to asymmetric compression forces. 
     Another important object is to provide an electrical connector of the character described which provides a reliable seal even when used with coaxial cables of different diameters and physical characteristics and sizes. 
     These and other objects and advantages of the present invention, along with features of novelty appurtenant thereto, will appear or become apparent in the course of the following descriptive sections. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       In the following drawings, which form a part of the specification and which are to be construed in conjunction therewith, and in which like reference numerals have been employed throughout wherever possible to indicate like parts in the various views: 
         FIG. 1  is a longitudinal isometric view of the preferred connector, showing it in an uncompressed preassembly or “open” position; 
         FIG. 2  is a longitudinal top plan view of the connector of  FIG. 1 , the bottom view substantially comprising a mirror image; 
         FIG. 3  is a longitudinal side elevational view of the connector of  FIGS. 1 and 2 , the opposite side view substantially comprising a mirror image; 
         FIG. 4  is a front end view, taken from a position generally above  FIG. 2  and looking down; 
         FIG. 5  is a rear end view, taken from a position generally below  FIG. 2  and looking up; 
         FIG. 6  is a longitudinal isometric view of the preferred connector similar to  FIG. 1 , but showing it in a compressed, “closed” position assumed after compression; 
         FIG. 7  is a longitudinal top plan view of the closed connector of  FIG. 6 , the bottom view substantially comprising a mirror image; 
         FIG. 8  is a longitudinal side elevational view of the closed connector of  FIGS. 6 and 7 , the opposite side view substantially comprising a mirror image; 
         FIG. 9  is a longitudinal isometric view of an alternative preferred connector, showing it in an uncompressed preassembly or “open” position; 
         FIG. 10  is a longitudinal isometric view of the alternative connector of  FIG. 9 , showing it in a compressed or “closed” position; 
         FIG. 11  is an exploded, longitudinal sectional view of the preferred connector; 
         FIG. 12  is an enlarged, longitudinal sectional view of the preferred barbless post; 
         FIG. 13  is an enlarged, longitudinal sectional view of the preferred hex head; 
         FIG. 14  is an enlarged, longitudinal sectional view of the preferred connector body; 
         FIG. 15  is an enlarged, longitudinal sectional view of the preferred end cap; 
         FIG. 16  is an enlarged, longitudinal sectional view of the preferred connector, shown in an uncompressed position, with no coaxial cable inserted; 
         FIG. 17  is a longitudinal sectional view similar to  FIG. 16 , showing the connector in the “closed” or compressed position, with no coaxial cable inserted; 
         FIG. 18  is a view similar to  FIG. 16 , showing the connector in an open position, with a prepared end of coaxial cable inserted; 
         FIG. 19  is a view similar to  FIG. 18 , showing the connector in a partially compressed position; 
         FIG. 20  is a view similar to  FIGS. 18 and 19 , showing the connector in a closed, fully compressed position, captivating the coaxial cable; 
         FIG. 21A  is an enlarged isometric view of the preferred sealing grommet; 
         FIG. 21B  is an enlarged elevational view of the preferred sealing grommet; 
         FIG. 22  is an enlarged sectional view of the uncompressed grommet taken generally along lines  22 - 22  of  FIG. 21B ; 
         FIG. 23  is an enlarged sectional view of the region of the grommet shown in  FIG. 22 , showing compression and material travel; and, 
         FIG. 24  is an enlarged plan view taken generally from the left of  FIG. 21 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     With initial reference directed to  FIGS. 1-5  of the appended drawings, an open F-connector for coaxial cable constructed generally in accordance with the best mode of the invention has been generally designated by the reference numeral  20 . The same connector disposed in a closed position is designated  21  (i.e.,  FIGS. 6-8 ). Connectors  20  and  21  are adapted to terminate an end of properly prepared coaxial cable, the proper preparation of which is well recognized by installers and others with skill in the art. After a prepared end of coaxial cable is properly inserted through the open bottom end  26  ( FIG. 1 ) of an open connector  20 , the connector is placed within a suitable compression hand tool for compression, substantially assuming the closed configuration of  FIG. 6 . 
     With additional reference directed to  FIGS. 11 and 13 , the preferred rigid, tubular, metallic nut  30  has a conventional faceted, preferably hexagonal drive head  32  integral with a protruding, coaxial stem  33 . Conventional, internal threads  35  are defined in the nut or head interior for rotatable, threadable mating attachment to a suitably-threaded socket. The open front mouth  28  of the connector (i.e.,  FIGS. 1 ,  13 ) appears at the front of stem  33  surrounded by annular front face  34  ( FIG. 13 ). A circular passageway  37  is concentrically defined in the faceted drive head  32  at the rear of nut  30 . Passageway  37  is externally, coaxially bounded by the outer, round peripheral wall  38  forming a flat, circular end of the connector nut  30 . An inner, annular shoulder  39  on the inside of head  32  is spaced apart from and parallel with outer wall  38  ( FIG. 13 ). A leading external, annular chamfer  40  and a spaced apart, rear external, annular chamfer  41  defined on hex head  32  are preferred for ease of handling. 
     An elongated, tubular body  44  ( FIGS. 11 ,  14 ) preferably molded from plastic is mounted adjacent nut  30 . Body  44  preferably comprises a tubular stop ring  46  (i.e.,  FIG. 11 ) that is integral with a reduced diameter shank  48  sized to fit as illustrated in  FIG. 11 . The elongated, outer peripheral surface  52  ( FIG. 14 ) of shank  48  is smooth and cylindrical. The larger diameter stop ring  46  used in the best mode has an annular, rear wall  54  ( FIG. 14 ) that is coaxial with shank  48 . The nut  30  rotates relative to the post and body and compression member. 
     In assembly, the end cap  56  is pressed unto body  44 , coaxially engaging the shank  48 . The end cap  56  discussed hereinafter (i.e.,  FIGS. 11 ,  15 ) will smoothly, frictionally grip body  44  along and upon any point upon body shank  48 , with maximum travel or displacement limited by stop ring  46 . In other words, when the end cap  56  is compressed unto the body of either connector  20 ,  21 , and the connector  20 ,  21  assumes a closed position (i.e.,  FIG. 6 ), annular wall  54  on the body stop ring  46  will limit maximum deflection or travel of the end cap  56 . 
     The resilient, preferably molded plastic body  44  is hollow. Stop ring  46  has an internal, coaxial passageway  58  extending from the annular front face  59  defined at the body front (i.e.,  FIG. 14 ) a major portion of the ring length. Passageway  58  extends to an inner, annular wall  60  that coaxially borders another passageway  62 , which has a larger diameter than passageway  58 . The elongated passageway  62  is coaxially defined inside shank  48  and extends to annular rear, surface  63  ( FIG. 14 ) coaxially located at the rear end  64  of the shank  48 . As best viewed in cross section as in  FIG. 14 , the annular rear surface  63  of body  44  is tapered proximate rear end  64  which generates a wedging action when the annular leading rear surface  65  contacts the grommet  67  when the connector  20  is compressed. 
     For moisture sealing, it is preferred that sealing grommet  67  be employed ( FIG. 11 ). The enhanced sealing grommet  67  is coaxially disposed within end cap  56  as explained in detail hereinafter. Grommet  67  is preferably made of a silicone elastomer. 
     With primary reference directed now to  FIGS. 11 and 12 , the post  70  rotatably, mechanically couples the hex headed nut  30  to the plastic body  44 . The metallic post  70  also establishes electrical contact between the braid of the coaxial cable (i.e.,  FIGS. 18 ,  19 ) and the nut  30 . The tubular post  70  defines an elongated shank  71  with a coaxial, internal passageway  72  extending between its front  73  and rear  74  ( FIG. 12 ). A front, annular flange  76  is spaced apart from an integral, reduced diameter flange  78 , across a ring groove  80 . A conventional, resilient O-ring  82  ( FIG. 11 ) is preferably seated within ring groove  80  when the connector is assembled. A post collar region  84  with multiple, miniature serrations  86  is press fitted into the body  44 , frictionally seating within passageway  58  (i.e.,  FIG. 11 ). In assembly it is also noted that post flange  76  (i.e.,  FIG. 12 ) axially contacts inner shoulder  39  ( FIG. 13 ). Inner post flange  78  axially abuts front face  59  ( FIG. 14 ) of body  44  with post  70  penetrating passageway  58 . The sealing O-ring  82  is circumferentially frictionally constrained within nut  30  coaxially inside passageway  37  ( FIGS. 11 ,  17 ). 
     It will be noted that the post shank  71  is substantially tubular, with a smooth, barbless outer surface terminating in a slightly chamfered, tapered end  77 . The shank end  77  penetrates the coaxial cable prepared end, such that the inner, insulated conductor penetrates post shank passageway  72  and coaxially enters the mouth  28  in nut  30 . Also, the braided shield of the coaxial cable is coaxially positioned around the exterior of post shank  71 , within annulus  88  ( FIG. 17 ) coaxially formed within body passageway  62  ( FIG. 14 ) between post  70  and the shank  48  of body  44  ( FIGS. 11 ,  14 ). 
     The preferred end cap  56  is best illustrated in  FIGS. 11 and 15 . The rigid, preferably metallic end cap  56  comprises a tubular body  92  that is integral and concentric with a rear neck  94  of reduced diameter. The neck  94  terminates in an outer, annular flange  95  forming the end cap rear and defining a coaxial cable input hole  97  with a beveled peripheral edge  98 . With all connector embodiments  20 ,  21  ( FIGS. 2 ,  6 ) and  23 ,  24  ( FIGS. 9 ,  10 ), an external, annular ring groove  96  is concentrically defined about neck  94  ( FIG. 15 ). The ring groove  96  is axially located between body  92  and flange  95 . The front of the end cap  56 , and the front of body  92  ( FIG. 15 ) is defined by concentric, annular face  93 . The external ring groove  96  is readily perceptible by touch. However, it is preferred that resilient ring  57  ( FIG. 11 ) be seated within groove  96  in connectors  20 ,  21  as seen in  FIGS. 3 and 6 . Internal ring groove  99  ( FIG. 15 ) seats the preferred sealing grommet  67  ( FIG. 11 ). 
     Hole  97  at the rear of end cap  56  ( FIG. 15 ) communicates with cylindrical passageway  100  concentrically located within neck  94 . Passageway  100  leads to a larger diameter passageway  102  defined within end cap body  92 . Ring groove  99  is disposed between passageways  100  and  102 . Passageway  102  is sized to frictionally, coaxially fit over shank  48  of connector body  44  in assembly. There is an inner, annular wall  105  concentrically defined about neck  94  and facing within large passageway  102  within body  92  that is a boundary between end cap body  92  and end cap neck  94 . Grommet  67  (i.e.,  FIGS. 11 ,  21 ) bears against wall  105  in operation. Once a prepared end of coaxial cable is pushed through passageways  100 , and  102  it will expand slightly in diameter as it is axially penetrated by post  70 . The deformed grommet  67  (i.e.  FIG. 22 ) whose axial travel is resisted by internal wall  105  ( FIG. 15 ) will be deformed and reshaped, “travelling” to the rest position assumed when compression is completed, as discussed below. After fitting compression, subsequent withdrawal of coaxial cable from the connector will be resisted in part by surface tension and pressure generated between the post shank and contact with the coaxial cable portions within it and coaxially about it. 
     The smooth, concentric outer surface of the connector body&#39;s shank  48  (i.e.,  FIGS. 11 ,  14 ) fits snugly within end cap passageway  102  when the end cap  56  is telescopingly, slidably fitted to the connector body  44 . Cap  56  may be firmly pushed unto the connector body  44  and then axially forced a minimal, selectable distance to semi-permanently retain the end cap  56  in place on the body (i.e., coaxially frictionally attached to shank  48 ). There is no critical detented position that must be assumed by the end cap. The inner smooth cylindrical surface  104  of the end cap  56  is defined concentrically within body  92  ( FIG. 15 ). Surface  104  coaxially, slidably mates with the smooth, external cylindrical surface  52  ( FIG. 14 ) of the body shank  48 . Thus the end cap  56  may be partially, telescopingly attached to the body  44 , and once coaxial cable is inserted as explained below, end cap  56  may be compressed unto the body, over shank  48 , until the coaxial cable end is firmly grasped and the parts are locked together. It is preferred however that the open mouth  106  at the end cap front have a plurality of concentric, spaced apart beveled rings  108  providing the end cap interior surface  104  with peripheral ridges resembling “teeth”  110  that firmly grasp the body shank  48  (i.e.,  FIGS. 11 ,  14 ). Preferably there are three such “teeth”  110  ( FIG. 15 ). 
     When the end cap  56  is compressively mated to the body  44 , teeth  110  can firmly grasp the plastic shank  48  and make a firm connection without radially compressing the connector body, which is not deformed in assembly. The end cap may be compressed to virtually any position along the length of body shank  48  between a position just clearing annular surface  65  (i.e.,  FIG. 14 ) and the annular wall  54  at the rear of the body stop ring  46  ( FIG. 14 ). Maximum deflection of the end cap is limited when the front face  93  of the end cap ( FIG. 15 ) forcibly contacts the annular rear wall  54  ( FIG. 14 ) of the connector body  44 . When the fitting is compressed during the compression cycle, the beveled surface  63  of body shank  48  at shank end  64  (i.e.,  FIG. 14 ) will compressively engage and deform the grommet  67 , as in  FIG. 20 , sealing the coaxial cable coaxially captivated within the compressed connector. However, the grommet configuration illustrated in the fully compressed position of  FIG. 20  occurs or results only after the “traveling” effects as the connector transitions between the position seen in  FIG. 18 , the intermediate compressed position of  FIG. 19 , and the compressed portion of  FIG. 20 . 
     In  FIG. 16  it can be seen that when the end cap  56  is first coupled to the shank  48  of body  44 , the shank end  64  (and annular surface  65 ) are axially spaced apart from the grommet  67  that is coaxially positioned within the rear interior of the end cap  56 . However, when the connector  20  is compressed during installation, the shank rear end  64  is forced into and against the grommet  67 , which deforms as illustrated by comparing  FIGS. 18-20 . The mass of the grommet  67  is radially and concentrically directed towards the coaxial cable to seal it. 
     In  FIGS. 18-20  a prepared end of coaxial cable  116  is illustrated within the connector. The coaxial cable  116  has an outermost, usually black-colored, plastic jacket  117  forming a waterproof, protective covering, a concentric braided metal sheath  118 , and an inner, copper alloy conductor  119 . There is an inner, plastic insulated tubular dielectric portion  121 . When the prepared end is first forced through the connector rear, passing through end connector hole  97  ( FIG. 15 ) and through passageways  100 ,  102 , the end cap  56  is uncompressed as in  FIG. 18 . The coaxial cable prepared end is forced through the annulus  88  between the post  70  and the inner cylindrical surface of shank  48  ( FIG. 14 ) with post  70  coaxially penetrating the coaxial cable between the conductive braid  118  and the dielectric insulation  121 , with the latter coaxially disposed within the post. The prepared end of the coaxial cable has its outer metallic braid  118  folded back and looped over insulative outer jacket  117 , forming looped back portion  118 B ( FIG. 18 ). The metal braid or sheath, as seen in  FIGS. 18-20 , makes electrical contact with the post  70  and, after full compression, contacts portions of the body. 
     Dielectric insulation  121  coaxially surrounds the innermost cable conductor  119 , and both are coaxially routed through the post. A portion of conductor  119  protrudes from the mouth  28  (i.e.,  FIG. 18 ) of the nut  30  on the connector. Thus an end of conductor  119  forms the male portion of the F-connector  20 ,  21 . Axial withdrawal of the coaxial cable after compression of the end cap  56  ( FIG. 20 ) is prevented by the deformed grommet  67 . Surface contact between portions of the coaxial cable and the post, both inside and outside the post, and surface contact of the deformed grommet with the coaxial cable adds to the withdrawal strength necessary to pull the coaxial cable away from the compressed fitting. Enhanced electrical contact between the post shank  71  and the braid  118  is also increased by grommet deformation ( FIG. 20 ). 
     Referring now to  FIGS. 21A ,  21 B, and  22 - 24 , enhanced sealing grommet  67  is generally toroidal. In cross section it is seen that grommet  67  in the best mode comprises two primary portions that are integral and coaxial. The outermost portion  130  (i.e., the outer diameter) of grommet  67  is of a generally rectangular profile, enabling the grommet  67  to seat within the end cap ring groove  99  discussed earlier. The innermost circumferential surface of the grommet is designated by the reference numeral  150  in  FIG. 21A , and the outermost circumferential surface is designated by the reference numeral  152 . In  FIG. 24  the inner diameter of the grommet  67  is designated by the reference numeral  154 , and in the best mode it is 8.4 mm. The larger, outer grommet diameter is designated by the reference numeral  156 , and in the best mode it is 10.5 mm. The ratio between the inner diameter and the outer diameter is preferably 1:1.25. 
     The grommet length along outer circumference portion  130  is designated by the reference numeral  131  ( FIG. 22 ), and in the best mode this distance is 3.6 mm. The inner grommet length  134  (i.e.  FIG. 22 ) proximate integral, inner, bulbous grommet portion  132  is longer than length  131 . Length  134  is preferably 3.95 mm. in the best mode. Thus, at and along its inner diameter region, grommet  67  is greater in length than at its outer diameter region along length  131  ( FIG. 20 ). The ratio between the smaller length  131  of the uncompressed grommet  67  at its outer diameter region ( FIG. 22 ) and the larger length  134  of the grommet at its inner diameter region is preferably approximately 0.8 to 1.0, or 80-100%. In the best mode it is 0.9, or 90%. 
     In  FIG. 22  the reference numeral  137  designates the preferred thickness of the grommet  67 , which is preferably 0.9 to 1.1 mm. In the best mode the thickness is 1.05 mm. The ratio between the thickness  137  and length  131  and is preferably between 0.20 and 0.35. In the best mode the ratio between the thickness  137  and length  131  and is 0.29. 
     Preferably, bulbous grommet portion  132  comprises a convex nose  133  that, in assembly, points into the interior of the connector towards the nut  30 . A slightly inclined neck  143  ( FIG. 22 ) transitions from the curved, outer edge  140  of the bulbous region to the outer diameter, reduced length  131  of the grommet that preferably seats within ring groove  99  (i.e.,  FIG. 15 ). The arcuate leading edge  140  of nose  133  has a radius  144 , substantially establishing a semicircular geometry. Preferably the length of radius  144  is approximately 8-10% of grommet length  134  ( FIG. 22 ). In the best mode radius the length of  144  is approximately 9% of grommet length  134  ( FIG. 22 ). 
     When the connector is compressed, shank  48  of body  44  and end cap  56  are forced together. Prior to compression the grommet  67  is seated proximate rear annular wall  105  in the end cap. The enhanced sealing grommet  67  is squeezed therebetween. Specifically, rear end  64  ( FIG. 14 ) of body shank  48  includes rear leading annular surface  65  that forcibly, contacts grommet  67  at neck  143 , and deforms and squeezes the grommet  67 . Grommet neck  143  is contacted by and ramped and deformed by contact with tapered surface  63  that generates a ramping and wedging action. When squeezed during installation, the grommet  67  deforms during compression as in  FIG. 19  that shows intermediate compression. It can be seen that the grommet body starts to elongate, and a traveling phenomena occurs. The bulbous convex portion  132  deforms and begins to travel horizontally towards the folded-back coaxial cable looped back portion  118 B ( FIG. 19 ). A portion of the mass of the grommet “extrudes” towards the interior of the fitting during this “traveling” phenomena. 
     However, travel continues until full compression is reached, as in  FIG. 20 , where portions of the mass of the grommet extrude towards the interior of the fitting of the coaxial cable until the coaxial cable braid looped back portion  118 B and the grommet nose region meet and intermingle. Specifically, this region of intermingling is designated by the reference numeral  148  in  FIG. 20 , which occurs because of an extrusion phenomenon during compression. Portions of the deformed grommet are compressed into the metallic braid of the coax, and substances of the grommet commingle with the metallic braiding of the coaxial cable sheath. The seal formed by material from grommet  67  thus travels into contact with the braid portion  118 B (i.e.,  FIG. 20 ), and some of the resilient material of the grommet  67  is forced into the interstitial regions of the wire web of the sheath. As seen, for example, in  FIG. 20 , grommet deformation pressures the coaxial cable all around its periphery, and forms a seal. 
     Thus, the preferred special sealing grommet  67  disposed in the end cap of the fitting is uniquely shaped with a rounded bulbous convex “nose”. This unique protrusion tends to grasp the outer, PVC jacket  117  and aids in locking the coaxial cable in position if unusual forces are applied to the coax. If the coaxial cable is accidentally pulled outwardly, (i.e., an axial pull), the surface friction between dissimilar materials (i.e., the post metal and the coaxial cable plastic) resists pulling apart of the components, even without barbs on the post shank. Radial deformation presses radially inwardly on the periphery of the coax, causing extra locking pressure to be exerted and further resisting the accidental extraction of the coax. 
     Referring to  FIG. 23 , the grommet  67  is illustrated in the final compressed orientation that it assumes after full installation compression. Neck is deformed as indicated, by contact with the body shank. The squeezed and elongated body has been designated by the reference numeral  149  ( FIG. 23 ). 
     From the foregoing, it will be seen that this invention is one well adapted to obtain all the ends and objects herein set forth, together with other advantages which are inherent to the structure. 
     It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims. 
     As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.