HK1093122B - Coaxial connector with a cable gripping feature - Google Patents

Description

Coaxial connector with cable clamping component

CROSS-REFERENCE TO RELATED APPLICATIONS

The present invention claims priority from U.S. provisional application 60/660653 filed on 11/3/2005.

Technical Field

The present invention relates generally to connectors for terminating coaxial cables and, more particularly, to coaxial cable connectors having a cable retention member.

Background

It has long been known to use connectors to terminate coaxial cables to connect the cables to various electronic devices, such as televisions, radios, and the like. Prior art coaxial connectors typically include: a connector body having an annular sleeve for receiving a coaxial cable; a nut rotatably coupled to the sleeve for providing mechanical coupling of the connector to an external device; and an annular rod interposed between the sleeve and the nut. An elastomeric O-ring may also be placed at the rotatable joint between the sleeve and the nut to provide a water-tight seal thereat. The ferrule includes a cable receiving end for insertably receiving an inserted coaxial cable, and at an opposite end of the connector body, the nut includes an internally threaded end portion that enables the body to be threadably connected to an external device.

Coaxial connectors of this type also include a locking sleeve to secure the cable within the coaxial connector body. A locking sleeve, typically formed of a resilient plastic, may be secured to the connector body to secure the coaxial connector thereto. In this regard, the connector body typically includes some form of structure to cooperatively engage the locking sleeve. Such structure may include one or more recesses or detents formed on the inner ring surface of the connector body that engage with cooperating structure formed on the outer surface of the sleeve. Coaxial cables of this type are shown and described in applicant's own united states patent 6530807.

Conventional coaxial cables typically include a center conductor surrounded by an insulator. A conductive foil is placed on the outer layer of the insulator and a braided conductive shield surrounds the metal foil covering the insulator. An outer insulating jacket surrounds the shield. To prepare the coaxial cable for termination, the outer insulating jacket is peeled back to expose a portion of the braided conductive shield, which is folded back over the jacket. A portion of the insulator covered by the conductive foil extends outwardly from the insulating sleeve and a portion of the center conductor extends outwardly from the interior of the insulator. After assembly onto the coaxial cable, the annular rod is inserted between the foil-covered insulator and the conductive shield of the cable.

One problem with existing coaxial connectors is that they often do not adequately grip the coaxial shielded cable, especially smaller diameter coaxial cables. In addition, it becomes difficult to seal the interior of the connector from the exterior components for smaller diameter cables.

Accordingly, there is a need to provide a coaxial cable connector with structural features to enhance clamping and sealing, particularly for smaller diameter cables.

Disclosure of Invention

It is an object of the present invention to provide a coaxial cable connector for terminating a coaxial cable.

It is another object of the present invention to provide a coaxial cable having a structure that enhances gripping of a coaxial cable, particularly a smaller diameter coaxial cable.

To effectively achieve these and other objects, the present invention provides a coaxial cable connector. The connector of the present invention generally comprises: a connector body having a rearward sleeve receiving end and an internal engagement surface; and an axially movable locking sleeve received in the rearward sleeve receiving end of the connector body. The locking sleeve has a rearward cable receiving end and an opposite forward connector insertion end. The forward connector insertion end is formed with at least one flexible finger for gripping a cable inserted in the sleeve when the locking sleeve is moved from a first position to a second position.

In a preferred embodiment, the connector body includes an inner ramp portion formed on the inner engagement surface for flexing the flexible finger radially inwardly when the locking sleeve is moved from the first position to the second position. The flexible fingers also preferably include tapered forward ends that form a sharp edge to facilitate gripping of the cable.

The connector may also include an annular post disposed in the connector body and a nut rotatably connected to the post. The sleeve and/or connector body may be made of a plastics material and preferably includes cooperating engagement surfaces to allow the sleeve to be moved axially from a first position in which a cable is loosely retained in the connector to a second position in which a cable is secured in the connector.

Preferably, the locking sleeve includes a plurality of flexible fingers that form a forward connector insertion end of the sleeve. In this case, at least two adjacent fingers of the sleeve may be connected by a web, thereby increasing the grip strength. Also, the flexible fingers may include a side slot formed therein to enhance the flexibility of the fingers.

The invention also includes a method of terminating a coaxial cable into a connector. The method comprises the following steps: an end of a cable is inserted into a rearward cable receiving end of a locking sleeve and the locking sleeve is moved axially relative to a connector from a first position in which a cable is loosely retained in the connector to a second position in which a cable is secured in the connector. Axial movement of the sleeve causes a flexible finger provided on the sleeve to flex radially inwardly to grip the end of the cable. In this way, the flexible finger may be engaged with an internal ramp portion of the connector body, which causes the finger to flex radially inward as the locking sleeve is moved from the first position to the second position.

To further enhance the grip of the cable, the annular rod disposed in the connector body preferably comprises: a first radially outwardly projecting barb located at a rearward end of the annular stem; and a second radially outwardly projecting barb forward of the first barb. More specifically, the pole may include: a shoulder portion in press-fit engagement with the connector body; and a tubular annular extension extending between the shoulder portion and the first and second barbs and having an outer diameter. Thus, the outer diameter of the first and second barbs is greater than the outer diameter of the annular tubular extension.

The present invention allows a user to insert a coaxial shielded cable into a coaxial connector with less force than is used in prior art connectors, thereby avoiding bending of the coaxial shielded cable. The present invention also enables the coaxial shielded cable to be firmly fixed in the coaxial connector without bending the coaxial shielded cable.

For a better understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings, and its scope is indicated in the appended claims.

Drawings

Fig. 1 is a perspective view of a fully assembled coaxial cable connector of the present invention;

fig. 2 is a side projection view of the prepared coaxial shielded cable;

FIG. 3 is a cross-sectional view of the connector of FIG. 1 taken along line 3-3;

FIG. 4 is a detail view of the cable gripping member of the sleeve of the present invention fully inserted into the body of the connector;

FIG. 5 is a top perspective view of the sleeve of the present invention;

FIG. 6 is a side projection view of the sleeve shown in FIG. 5;

FIG. 7 is a cross-sectional view of another embodiment of the coaxial connector of the present invention;

FIG. 8 is a cross-sectional view of the connector of FIG. 7 in a closed position with a cable secured therein;

FIG. 9 is a perspective view of the sleeve shown in FIGS. 7 and 8;

FIG. 10 is a perspective view of another embodiment of a sleeve;

fig. 11 is a perspective view of yet another embodiment of a sleeve.

Detailed Description

Referring to fig. 1, a coaxial connector 30 according to the present invention is shown. The connector 30 has a housing 32 (sometimes referred to as a "connector body" or "ferrule") having a first end 34 and a sleeve 40 that receives a coaxial shielded cable. Located at the opposite end to the first end 34 is a second end 38 having twist lock means 31 for connecting the connector 30 with the required mating means (not shown). The connector 30 is shown in an assembled, complete and compact configuration. The housing 32 and the sleeve 40 may have a cylindrical outer shape.

A typical coaxial shielded cable 10 is shown in fig. 1 and 3. The coaxial shielded cable 10 has a center conductor 12 surrounded by an insulating layer 14. The insulating layer 14 is covered by a foil 16 and a metal braid 18. The braid 18 is in turn covered by an outer layer 20, which may be plastic or other insulating material.

To prepare the coaxial shielded cable 10 for use in the connector 30, the cable is stripped using wire cutters or similar devices. A portion of the insulating layer 14 is removed and a portion of the center conductor 12 is exposed. The foil 16 is still covered by the insulating layer 14. The metal braid 18 is folded back over the outer layer 20 to form a folded portion 21. The overlapping portion 21 extends partially beyond the length of the outer layer 20. The prepared end 22 of the coaxial shielded cable 10 is shown in fig. 2 ready for use with the connector 30.

Referring to fig. 1 and 3, the connector 30 will be described in more detail. As described above, the connector 30 has a substantially cylindrical housing 32. The housing 32 may be made of a metallic material such as aluminum or copper that may be cast, extruded or machined. The housing 32 has a first end 34 with an inner diameter 36 sized to receive the outer diameter 48 of the sleeve 40 with minimal remaining space. The housing 32 has an opposite end 38. A sloped wall 42 is disposed on the inner surface 37 of the housing 32 between the first end 34 and the second end 38. As will be discussed in further detail, the wall 42 cooperates with the sleeve 40 to secure the coaxial shielded cable 10 within the connector 30. The opening 46 is located in the center of the sloped wall 42. The opening 46 is sized to receive the post 66, as described in further detail below.

Referring to fig. 3, the connector 30 also includes a terminal assembly 50 having terminals 56 that are centrally axially located within the housing 32. The terminals 56 may be made of a conductive material such as aluminum or copper. The terminals 56 may be secured in the housing 32 using a first insulative cap 52 and a second insulative cap 53. The first and second insulative caps 52, 53 are preferably disc-shaped and sized to fit into the housing 32 through the second end 38. The first insulating cover 52 and the second insulating cover 53 are made of a nonconductive material. The first and second insulating caps 52 and 53 have central apertures 54 and 55, respectively, sized to allow passage of the terminal 56. The first and second insulating caps 52, 53 are secured in place in the housing 32 by a friction or contact fit. However, it is contemplated that other types of connections may be used. The first and second insulating covers 52 and 53 may be spaced apart from each other in the case 32, thereby forming a space 51. In another embodiment (not shown), it is contemplated that the first and second insulating covers 52, 53 are constructed as a single component.

The terminal 56 has a hollow portion 60 sized to receive the center conductor 12 of the coaxial shielded cable 10. The terminal 56 has a first end 57 that extends toward the first end 34 of the housing 32. The first end 57 forms a hollow portion 60 leading to the terminal end 56. Located within the hollow portion 60 is at least one spring contact 58 made of a resilient metallic material and arranged to contact the center conductor 12 of the coaxial shielded cable 10. In another embodiment (not shown), the spring contact 58 may be integrally formed with the terminal 56, thereby forming an integral terminal. A second end 58 of the terminal 56, opposite the first end 57, takes the form of a prong extending toward the second end 38 of the connector 30.

Still referring to fig. 3, the terminal assembly 50 further includes a post 66 adjacent the second insulating cover 53. The post 66 is sized to extend through the opening 46 of the angled wall 42 toward the first end 34. The post 66 is generally cylindrical with a smooth outer surface 67 and is fixed in position between the insulator 52 and the rear wall 42. The rod is made of a metal material such as aluminum or copper. The post 66 is centrally located at the first end 34 so that it is disposed between the foil 16 and the braid 18 when the coaxial shielded cable 10 is inserted into the connector 30. The smooth outer surface 67 of post 66 minimizes the force required to insert coaxial shielded cable 10 into connector 30 and reduces the likelihood of buckling. The smooth outer surface 67 of the post 66 also allows for simple manufacture of the connector. As will be described in greater detail below, the post 66 preferably has a plurality of raised barbs 64 on the outer surface 67 thereof which serve to grip the braid 18 when the coaxial shielded cable 10 is pressed against the post 66.

Referring again to fig. 5 and 6, movably received in the first end 34 of the housing 32 is a sleeve 40 that securely holds the coaxial shielded cable 10 in the connector 30. The sleeve 40 may be cylindrical with a base 70 with an upwardly extending sidewall 72. The side walls 72 terminate at an upper portion 74 that is substantially parallel to the base. A sleeve bore 76 extends from the base 70 through the sleeve 40 to the upper portion 74. The sleeve aperture 76 is sized to allow the coaxial shielded cable 10 to pass through the sleeve 40 with minimal clearance.

A plurality of resilient tabs or fingers 78 are positioned around the opening of the sleeve aperture 76 in the upper portion 74 of the sleeve 40. The resilient tabs 78 have angled or angled ends 80 (fig. 6) that are positioned on the sleeve 40 such that when the sleeve is inserted into the first end 34 of the housing 32, the angled walls 42 formed on the inner surface 37 of the housing 32 will contact the angled portions 80 of the resilient tabs 78. Thereby pushing them towards the center of the sleeve aperture 76.

The sleeve 40 may also have an annular rim 86 on the outer surface 73 of the sidewall 72. The housing 32 may have a corresponding groove 88 on its inner surface 37, the groove 88 receiving the annular rim 86 to form a cooperating detent structure between the sleeve 40 and the housing. Preferably, the outer diameter of the sleeve 40 is sized smaller than the inner diameter 36 of the first end 34 so that the sleeve 40 may be inserted into the first end 34.

To apply the present invention, a user first prepares the coaxial shielded cable 10 as shown in fig. 2. The coaxial shielded cable 10 is then inserted through the sleeve aperture 76 of the sleeve 40 such that the overlapping portion 21 of the coaxial shielded cable 10 extends past the resilient tabs 78. The user then pushes the coaxial shielded cable 10 and the upper portion 74 of the sleeve 40 into the first end 34 of the connector 30. As the user pushes the coaxial shielded cable 10 into the connector 30, the terminal 56 and spring contact 58 receive the center conductor 12. Simultaneously, the rod 66 is advanced between the braid 18 and the foil 16 to establish electrical and mechanical engagement with the coaxial shielded cable 10.

Referring to fig. 4, after the coaxial shielded cable 10 is fully inserted into the jacket 32 such that the post 66 is inserted between the braid 18 and the foil 16, the sleeve 40 is pushed into the jacket 32 such that the resilient tabs 78 will contact the contact portions 44 of the angled walls 42. The resilient tab 78 is shown in phantom before contacting the contact portion 44. The contact portion 44 of the wall 42 and the angled portion 80 of the resilient tab 78 contact each other to deflect the resilient tab 78 toward the center of the sleeve aperture 76. As the resilient tabs 78 are biased, they are pressed into the outer layer 20 to securely hold the coaxial shielded cable 10 in place as shown in fig. 4. Preferably, the contact portion 44 has a taper of a dimension less than the resilient tab 78 extending from the sleeve 40.

The user continues to insert the sleeve 40 into the first end 34 until the annular rim 86 engages the groove 88 in the inner surface 37 of the first end 34, thereby securing the sleeve 40 in place. At the same time, the upper flange 71 of the base 70 may engage the first end 34, thereby indicating to the user that the sleeve 40 has been fully inserted into the first end 34. The resulting pressure between the resilient tabs 78 and the posts 66, as well as the additional clamping force provided by the barbs 64, prevent the coaxial shielded cable 10 from being inadvertently removed from the connector 30.

Referring now to fig. 7 and 8, another embodiment of a coaxial cable connector according to the present invention is shown. A connector 100 of the type shown in fig. 7 and 8 is known in the industry as a C4 connector. It generally comprises four elements: a connector body 102, an annular rod 104, a rotatable nut 106, and a movable locking sleeve 108. However, it is contemplated that the connector body 102 and the annular rod 104 may be integrated as one element and/or that other fastening devices other than the rotatable nut 106 may be used. Additionally, a resilient sealing O-ring 107 may be placed at the junction between the connector body 102, the annular rod 104 and the nut 106, thereby providing a water-tight seal thereat.

The connector body 102 is an elongated, generally cylindrical member that is preferably made of plastic to minimize cost. Alternatively, the connector body 102 may be made of metal or the like. The connector body 102 has one end 103 connected to the annular rod 104 and the nut 106 and an opposite sleeve receiving end 110 for insertably receiving a sleeve 108. The sleeve receiving end 110 defines an internal engagement surface 112 having one or more grooves 114 and/or projections 115 that engage mating grooves 116 and/or projections 117 formed on the outer surface of the sleeve 108 to lock the sleeve in the body 108.

The annular rod 104 includes: a flanged base portion 118 rotatably received in the rod receiving space in the nut 106; and a widened shoulder portion 120 that provides a press-fit securement of the post in the connector body 102. The annular stem 104 also includes an annular tubular extension 122 that extends rearwardly in the body 102 and into the sleeve 108. As mentioned above, the rear end of the tubular portion 122 preferably includes a radially outwardly extending beveled flange portion or "barb" 124 having a forward facing edge 125 that presses the outer jacket of the coaxial cable against the inner diameter of the body to secure the cable in the connector. Alternatively, and/or depending on the method of forming the post 104, the barb 124 may be more rounded as opposed to having a sharp edge 125. In any event, as will be described in further detail below, the extension 122 of the post 104, the body 102, and the sleeve 108 form an annular cavity 126 for receiving the outer jacket and shield of the inserted coaxial cable.

The nut 106 may be of any form, such as a hex nut, a knurled nut, a wing nut, or any other known connection device, and the nut 106 is rotatably coupled to the annular rod 104 to provide mechanical coupling of the connector 100 to an external device. The nut 106 includes an internally threaded end portion 128 that allows the connector 100 to be threadably connected to an external device. The sleeve 108 and the internally threaded end 128 form opposite ends of the connector 100.

The locking sleeve 108 is a generally tubular member having a rearward cable-receiving end 130 and an opposite forward connector-insertion end 132, and is movably coupled to the inner surface 112 of the connector body 102 such that the sleeve 108 is movable in the connector body 102 toward the nut 106 along arrow a in fig. 7 and 8 from a first position shown in fig. 7 to loosely retain the cable 10 in the connector 100 to a second, more forward position shown in fig. 8 to secure the cable in the connector.

Preferably, the locking sleeve 108 further includes a flanged head 134 at the rearward cable receiving end 130 thereof. The head 134 has an outer diameter greater than the inner diameter of the body 102 and includes a forward vertical wall 136 that serves as an abutment surface where the rearward end of the body 102 stops to prevent further insertion of the sleeve 108 into the body 102.

The forward end 132 of the sleeve 108 is also formed with a plurality of flexible fingers 138 extending forwardly. The fingers 138 are bent inwardly by an internal ramp 140 formed on the inner engagement surface 112 of the connector body 102 during insertion of the sleeve 108 into the body. As the fingers 138 flex inwardly, they engage the outer jacket of the cable 10, thereby enhancing the grip of the cable in the connector.

Referring again to fig. 9, the fingers 138 may be formed by providing a longitudinal slot 142 in the front end of the sleeve 108. Additionally, the fingers 138 may include tapered ends 144, thereby forming relatively sharp edges. The sharp edge 144 will snap into the cable 10 as the inner ramp portion 140 of the connector body 102 deforms the fingers 138, thereby providing a greater clamping force and preventing the cable from being pulled out of the connector.

Alternatively, as shown in fig. 10, the fingers 138 may be integral with one another, with the web 146 connecting adjacent fingers. The web 146 may be located anywhere between the inner and outer diameters of the fingers 138. In yet another embodiment, as shown in FIG. 11, a side groove 148 may be formed in the fingers 138 to increase the flexibility of the fingers.

In use, the cable 10 is prepared as described above and the outer jacket 20 is peeled open to expose a portion of the braid 18. From which a portion of the foil covered insulator 14 extends and a portion of the conductor 12 extends. After a portion of the shield 18 is folded back and around the jacket 20, the cable 10 may be inserted into the connector 100 with the sleeve 108 already connected to the body 102, as shown in fig. 7. In this technique, the prepared cable 10 is inserted through the rearward end 130 of the sleeve 108 and the extension 122 of the post 104 is inserted between the foil covered insulator 14 and the metal shield 18 so that the shield and jacket 20 are left between the annular region 126 formed between the post 104 and the sleeve 108. When the sleeve 108 and body 102 are connected in the first position as shown in fig. 7, sufficient clearance is provided between the sleeve and the post 104 so that the tubular post extension 122 can be easily inserted between the insulator 14 and the shield 18 of the cable 10.

Once the cable 10 is properly inserted, the sleeve 108 can be moved axially forward in the direction of arrow A from the first position shown in FIG. 7 to the second position shown in FIG. 8. The sleeve 108 is moved axially forwardly until the forward abutment surface 136 of the sleeve head 134 engages the rearward end of the body 102. A suitable compression tool may be used to cause movement of sleeve 108 from its first position to its second position to secure cable 10 to connector 100.

As the sleeve 108 moves to its second position, the jacket 20 and shield 18 of the cable 10 begin to be compressed and become trapped in the annular region 126 between the barb 124 of the post 104 and the sleeve 108. As such, the inner surface of the sleeve 108 is preferably provided with an inwardly directed shoulder portion 149 to facilitate pressing the cable jacket 20 against the barbs 124 of the post 104. Also, as the sleeve 108 moves to its second position, the sleeve fingers 138 are pushed inwardly by a ramp 140 formed in the connector body 102 to further engage the cable jacket.

To further enhance the locking of the cable 10, the post 104 of the present invention is preferably provided with a second annular cable retention barb 150 disposed forwardly of the rearward end barb 124. The rearward end barb 124 and the forward barb 150 are both annular projections that extend radially outward from the outer diameter of the tubular extension 122. In other words, like the first barb 28, the second barb 74 is a generally annular, radially outwardly extending, angled flange portion of the post 104 having a forward edge that compresses the outer jacket of the coaxial cable to secure the cable in the connector 100. The second barb 150 may provide improved mechanical retention of the cable as well as improved electromagnetic isolation and shielding of signals in the connector.

Although the illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention.

Various modifications to the above-described and illustrated structures will be readily apparent to those skilled in the art. Accordingly, the specific scope of the disclosure is defined by the appended claims.

Claims (8)

1. A coaxial cable connector comprising:

a connector body having a rearward sleeve receiving end and an internal engagement surface;

an axially movable locking sleeve received in said rearward sleeve receiving end of said connector body, said locking sleeve having a rearward cable receiving end and an opposite forward connector insertion end, said forward connector insertion end being formed with at least one flexible finger for gripping a cable inserted into said sleeve when said locking sleeve is moved from a first position to a second position; and

an annular post disposed in the connector body, the annular post comprising: a shoulder portion in press-fit engagement with the connector body; a first radially outwardly projecting barb located at a rearward end of the annular stem; a second radially outwardly projecting barb forward of said first barb; and a tubular annular extension extending between the shoulder portion and the first and second barbs and having an outer diameter, the outer diameter of the first and second barbs being greater than the outer diameter of the annular tubular extension.

2. The coaxial cable connector of claim 1, wherein said connector body includes an inner ramp portion formed on said inner engagement surface for flexing said flexible finger radially inwardly when said locking sleeve is moved from said first position to said second position.

3. The coaxial cable connector of claim 1, further comprising a nut rotatably connected to said connector body.

4. The coaxial cable connector of claim 1, wherein said sleeve is made of a plastic material.

5. The coaxial cable connector of claim 1, wherein said connector body is made of a plastic material.

6. The coaxial cable connector of claim 1, wherein the flexible finger includes a tapered forward end forming a sharp edge to facilitate gripping of the cable.

7. The coaxial cable connector of claim 1, wherein said locking sleeve includes a connector body outer engagement surface that cooperates with said inner engagement surface of said connector body to permit axial movement of said sleeve from said first position in which a cable is loosely retained in the connector to said second position in which a cable is secured in the connector.

8. The coaxial cable connector of claim 1, wherein an annular region is defined between said first and second barbs, said locking sleeve further including an inner surface and an inwardly directed shoulder portion disposed on said inner surface, said inwardly directed shoulder portion being disposed within said annular region between said first and second barbs when said locking sleeve is in said second position to facilitate cable compression.