Coaxial cable connector

[0002] 1. Field of the Invention

[0003] The present invention relates to a coaxial cable connector and more particularly to an in-line coaxial cable connector capable of connecting together two flush cut cables of two different diameters, suitable for use in radio and video signal transmission.

[0004] 2. Description of the Prior Art

[0005] Currently there are numerous connectors which enable two coaxial cables to be spliced together. However, these connectors require the cable to be cut such that the insulating cover is cut back to expose the woven metallic sheath. Additionally, the cable must be cut such that the internal wire conductor extends beyond the remaining portion of the cable to contact a female receptive portion of the cable. This cutting requires the skill of an experienced cable layer and often a cut is made too deep or all the way through the cable. Such an improper cut will require an additional cut thus shortening the length of the cable and wasting the portion which was improperly severed. This type of cutting takes an additional amount of time when attempting to splice together two coaxial cables.

[0006] For example U.S. Pat. No. 5,217,392 discloses a coaxial cable splice connector comprising outer conductor shells to make contact with the woven metallic sheath of each cable and an inner conductor bore to make contact with the central wire conductor of each cable. However, the cables to be spliced in U.S. '392 must first be cut to peel back the outer insulator member and expose the woven metallic sheath. Additionally, the cable must be cut such that the inner wire conductors extends past the remaining portion of the cable to engage the inner conductor bore.

[0007] There is a need to enable two coaxial cables to be spliced together in-line which requires ease of assembly and simple cut of the cables to be spliced without any reduction in the quality of radio or video reception.

[0008] Furthermore, there are various types of radio and video cables on the market having different diameters. Specifically, different makes of coaxial cable have an inner dielectric of varying diameters. Different coaxial cable connectors are needed in order to splice together cables having different diameters. Therefore, there is a need for the coaxial cable connector to accommodate cables of different diameter dielectric material.

[0009] The present invention attempts to remedy the drawbacks of the prior art and provide a simpler, less expensive device which is easier to assemble, enables to accommodate cables of different diameters and maintains the quality of radio and video reception.

[0010] It is therefore, the principal object of the present invention to provide an improved in-line cable connection suitable for use with a radio or video receptive antenna.

[0011] It is also an object of the present invention to allow the simple connection of two coaxial cables that have been simply transversely cut straight through wherein the end of the cable remains flush.

[0012] It is also an object of the invention to provide a means to secure a cable to the connector wherein a collapsible sleeve is mounted about the connector and a projection engages the connector to prevent relative rotation.

[0013] It is also an object of the invention to provide a coaxial in-line connector which requires no specialized tool other than a simple cutting tool to cut the ends of the cables in order to splice the cables together.

[0014] Further object of this invention is to provide a coaxial in-line connector which enables the simple connection of coaxial cables of two different diameters.

[0015] FIG. 1 is a longitudinal sectional view of the in-line connector connecting two coaxial cables.

[0016] FIG. 2 is an exploded longitudinal sectional view of the in-line connector.

[0017] FIG. 3 is a longitudinal sectional view of the interface connector.

[0018] FIG. 4 is a transverse sectional view of the interface connector taken along line 4—4 of FIG. 3.

[0019] FIG. 5 is an end view of the collapsible sleeve taken along line 5—5 of FIG. 6.

[0020] FIG. 6 is a longitudinal sectional view of the collapsible sleeve.

[0021] FIG. 7 is an end view of the collapsible sleeve taken along line 7—7 of FIG. 6.

[0022] FIG. 8 is an exploded longitudinal sectional view of the preferred embodiment of the in-line connector.

[0023] FIG. 9 is a transverse sectional view of the interface connector taken along line 9—9 of FIG. 8.

[0024] Referring to FIGS. 1-7 in detail, one embodiment of the cable joint of the present invention is depicted in FIG. 1, showing the joining of two coaxial cables 9. A pair of cables 9 each have an inner conductor 10 concentrically embedded within a dielectric material 12 which is in turn concentrically surrounded by a woven metallic sheath 11 which is in turn is concentrically surrounded by an insulating material 13. The ends of the cables are generally flush cut to define a generally flat transverse area as shown in FIG. 1 at 14. The flush cut end of each cable lies adjacent to an exposed portion of the connector 1 and insulator 2.

[0025] Now referring to FIG. 2, an interface connector 1 has a centrally located nut portion 5 which has an annular inward extending portion 5a, the axis of which defines a common longitudinal axis. Within the annular inward extending portion 5aof the nut portion 5 are coaxially disposed an insulator 2 and a conductor 3. The width of the insulator 2 is substantially equal to the width of the annular inward extending portion 5aso as to provide a generally planer or flat exposed surface. The conductor member 3 is of such a width that when centrally disposed within insulator 2 it extends beyond the insulator on both sides. This extended portion of the conductor member 3 provides an exposed surface to contact the inner conductor member 10 of the cables 9 which are to be spliced together. The length that the conductor 3 extends from the insulator is such as to afford a good contact with the inner conductor 10 of the cable 9 while allowing the transverse surface area of the cable to rest next to the generally planar surface defined by the insulator 2 and inwardly extending portion of the central nut portion 5.

[0026] From the central nut portion 5 extends a pair of metallic sleeves 4aand 4b. Sleeves 4a, 4bare coaxially aligned with the common axis, defined by the axis of the annular extending portion 5a, and extend in opposite directions from the central nut portion 5. The diameter of each of the metallic sleeves 4aand 4bis substantially the same as the diameter of woven metallic sheath 11 of the coaxial cables 9 so as to make good contact therebetween. The diameter of the metallic sleeves 4aand 4bcan hence be either slightly larger or slightly smaller than the woven metallic sheath 11.

[0027] In order to splice two coaxial cables together each cable 9 is completely severed in a direction transverse to its axis to expose a flush end surface. The cable 9 and the interface connector 1 are coaxially aligned and then simply pushed toward one another such that one side of the interface connector is inserted into one of the cables. The cable 9 and connector 1 are displaced toward one another such that the exposed flush surface of the cable rests against or near the generally planar surface defined by the insulator and inward extending portion of central nut 5 as shown at 14. The connector conductor 3 extends into the dielectric material 12 to make contact with the inner conductor 10 of cable 9. The metallic sleeves 4aand 4bextend into the cable 9 and surround the dielectric material and make contact with the metallic sheath 11 of the cable 9. The diameter of the metallic sleeve is such that it either makes contact with the inner peripheral surface or the outer peripheral surface of the metallic sheath 11 while being disposed within the cable insulator 13. The connection between each of the inner conductors 10 of each cable 9 is made through the conductor member 3 of the interface conductor 1. The connection between the woven metallic sheath 11 of each cable 9 is made through the two metallic sleeves 4aand 4band the central nut portion 5 of the interface connector 1. The central nut portion 5 and the metallic sleeves 4aand 4bare integrally formed of a material such as copper, or the like, to afford a good connection. The connection is thus established between each coaxial cable.

[0028] In order to secure the connection of each cable 9 to the interface cable 1, a collapsible sleeve 7 and a locknut 8 are provided. At one end of the collapsible sleeve 7 a portion is threaded on its outer peripheral surface 7a. Longitudinal slits 7bare cut along this threaded portion 7aof sleeve 7 so that the threaded portion 7acan expand and contract to accommodate cables of varying diameter. At the other end of sleeve 7 extend a plurality of projections 7cwhich extend in the longitudinal direction. Central nut portion 5 of the interface connector has a plurality of longitudinal notches 6 extending along its entire width parallel to the commonly defined axis. These notches 6 correspond to each of the projecting portions 7cof the collapsible sleeve 7. Each projection portion 7cis inserted into a corresponding notch 6 in order to prevent relative rotation between the interface connector 1 and the collapsible sleeve 7. A lock nut 8 having a threaded internal surface 8athreadingly engages the external surface 7aof the collapsible sleeve 7 such that as the lock nut 8 is tightened the diameter of the threaded portion of the collapsible sleeve 7ais decreased.

[0029] The assembly and securement of the connection will now be described. Once each cable 9 has been flush cut, the locknut 8 and then the collapsible sleeve 7 are slid over each cable 9. The collapsible sleeve 7 is disposed over the cable, and consequently over the insulator portion 13 thereof, such that the projecting portions 7cextend toward the flush cut end of the cable 9. One end of the interface connector 1 is coaxially aligned with one of the cables 9 and the two are simply urged toward one another such that one end of the interface connector 1 is inserted into the cable 9. The collapsible sleeve 7 is slid up towards the interface connector 1 until the projecting portions 7cof the collapsible sleeve extend into a corresponding notch 6 of the central nut portion to prevent relative rotation therebetween. The lock nut 8 is then slid up to and threadably engages the collapsible sleeve 7. The locknut 8 is tightened so as to reduce the diameter of the collapsible sleeve 7 to crimp the insulator portion 13 of cable 9 against one of the metallic sleeves 4aor 4b. This crimping action affords a tight friction connection and prevents the cable 9 from dislodging from the interface connector 1. This crimping action additionally, urges the woven the metallic sheath 11 of cable 9 against the external surface of the metallic sleeves 4aand 4bto afford a better connection therebetween. Once one cable 9 is secured, the same process is repeated for the other cable to the other side of the interface connector 1; a stable in-line electrical connection between each cable has thus been established.

[0030] In an alternate method of assembly two longitudinal cuts may be made into the insulator portion 13 to ease the insertion of the metallic sleeves 4aand 4bwithin the insulator portion 13 and over the dielectric material 12. These two cuts preferably are spaced 180° apart so as to be opposite one another. The length of these cuts would be sufficient to allow the insulator portion to expand slightly to ease the insertion of the metallic sleeve over the dielectric material 12 and within the insulator portion 13. Additionally, the length of the cuts should not exceed the width of the sleeve 7 so as to ensure that neither the metallic sheath 11 nor the metallic sleeve is exposed to the environment after complete assembly of the connector. When cutting the insulator portion longitudinally, the depth of the cut should not exceed the thickness of the insulator portion in order to preserve the integrity of the woven metallic sheath 11 and dielectric material 12.

[0031] Referring now to FIG. 8 that illustrates the preferred embodiment of the present invention, an interface connector 20 has a centrally located nut portion 25 which has an annular inward extending portion 25a, the axis of which defines a common longitudinal axis. An insulator 22 and a conductor 23 are coaxially disposed within the annular inward extending portion 25aof the nut portion 25. The width of the insulator 22 is substantially equal to the width of the annular inward extending portion 25aso as to provide a generally planer or flat exposed surface. The conductor member 23 is of such a width that when centrally disposed within insulator 22 it extends beyond the insulator on both sides. This extended portion of the conductor member 23 provides an exposed surface to contact the inner conductor member 10 of the cables 9 which are to be spliced together. The length that the conductor 23 extends from the insulator is such as to afford a good contact with the inner conductor 10 of the cable 9 while allowing the transverse surface area of the cable to rest next to the generally planar surface defined by the insulator 22 and inwardly extending portion of the central nut portion 25.

[0032] From the central nut portion 25 extends a pair of metallic sleeves 24aand 24b. Sleeves 24a, 24bare coaxially aligned with the common axis, defined by the axis of the annular extending portion 25a, and extend in opposite directions from the central nut portion 25. The exterior diameter of the metallic sleeves 24aand 24bcan be either slightly larger or slightly smaller than the diameter of the woven metallic sheath 11. Each of said sleeves 24a, 24bcomprises two sections having different interior diameters in order to accommodate two different types of coaxial cables having dielectric material 12 of different diameters: a first section 24a′, 24b′ adjacent to the central nut portion 25, and a second section 24a″, 24b″ adjacent to the first sections 24a′ and 24b′. An interior diameter of the first section 24a′, 24b′ is smaller than an interior diameter of said second section 24a″, 24b″ so that the first section 24a′, 24b′ accommodates large diameter cables, while the second section 24a″, 24b″ accommodates smaller diameter cables. A ramp section 24a′″, 24b′″ of varying internal diameter is located between the first section 24a′, 24b′ and the second section 24a″, 24b″, providing smooth transition between those first and second sections. In order to secure the connection of each cable 9 to the interface cable 20, a collapsible sleeve 27 and locknut 28 are provided. At one end of the collapsible sleeve 27 a portion is threaded on its substantially cylindrical outer peripheral surface 27aand an exterior end portion 27dof the collapsible sleeve 27 is tapered. Longitudinal slits 27bare cut along the threaded portion 27aand the tapered portion 27dof the sleeve 27 so that the portion of the sleeve 27 can expand and contract to accommodate cables of varying diameter. At the other end of sleeve 27 a plurality of projections 27care provided which extend in the longitudinal direction. The central nut portion 25 of the interface connector has a plurality of longitudinal notches 26 extending along its entire width parallel to the commonly defined axis. These notches 26 correspond to each of the projecting portions 27cof the collapsible sleeve 27. Each projection portion 27cis inserted into a corresponding notch 26 in order to prevent relative rotation between the interface connector 20 and the collapsible sleeve 27. A locknut 28 has a threaded internal surface 28aat one end of the locknut 28 and an internal inwardly tapered surface 28bat the other end. The interior diameter of the internal inwardly tapered surface 28bprogressively decreases toward said other end of the locknut 28. The threaded internal surface 28aof the locknut 28 threadingly engages the external threaded surface 27aof the collapsible sleeve 27 such that as the locknut 28 is tightened, the internal tapered surface 28bof the locknut 28 engages exterior tapered portion 27dof the collapsible sleeve 27 and the diameter of the threaded portion of the collapsible sleeve 27ais decreased positively clamping the insulator portion 13 of the cable 9 against the external surface of the sleeves 24aand 24b.

[0033] The assembly and securement of the connection in accordance with the preferred embodiment of the invention will now be described. Once each cable 9 has been flush cut, the locknut 28 and then the collapsible sleeve 27 are slid over each cable 9. The collapsible sleeve 27 is disposed over the cable, and consequently over the insulator portion 13 thereof, such that the projecting portions 27cextend toward the flush cut end of the cable 9. One end of the interface connector 20 is coaxially aligned with one of the cables 9 and the two are simply urged toward one another such that one end of the interface connector 20 is inserted into the cable 9. If the cable of small diameter is employed, it engages the first sections 24a′, 24b′ of the metallic sleeves 24aand 24b. However, when the cable of large diameter is employed, it engages the second sections 24a″, 24b″ of the metallic sleeves 24aand 24b. Then the collapsible sleeve 27 is slid up towards the interface connector 20 until the projecting portions 27cof the collapsible sleeve extend into a corresponding notch 26 of the central nut portion to prevent relative rotation therebetween. The lock nut 28 is then slid up to and threadably engages the collapsible sleeve 27. The locknut 28 is tightened so as to engage its internal tapered surface 28bwith the external tapered portion 27dof the collapsible sleeve 27 and reduce the diameter of the collapsible sleeve 27 to crimp the insulator portion 13 of cable 9 against one of the metallic sleeves 24aor 24b. This crimping action affords a tight friction connection and prevents the cable 9 from dislodging from the interface connector 20. This crimping action additionally, urges the woven the metallic sheath 11 of cable 9 against the external surface of the metallic sleeves 24aand 24bto afford a better connection therebetween. Once one cable 9 is secured, the same process is repeated for the other cable to the other side of the interface connector 20; a stable in-line electrical connection between each cable has thus been established.

[0034] The preferred method of assembly and securement of the cable connection in accordance with the alternative embodiment of the invention, is substantially identical to one that was described above in connection with the first embodiment of the present invention.

[0035] While the coaxial cable connector of this invention has been shown and described with reference to the particular embodiments, it will be understood to those possessing skill in the art that various changes to the form and detail may be made therein without departing from the spirit and scope of the invention.