Electrical Connector With Automatic Conductor Termination

This invention relates to electrical connectors and especially, but not exclusively, to coaxial connectors.

The termination of a coaxial cable to a connector normally involves the preparation of the cable end so all layers of the cable are exposed, including the inner conductor, inner insulation, outer conductor in the form of a screen braid, and the outer insulation. The end of the inner conductor is normally terminated to a removed contact by soldering or crimping, with the inner contact then inserted and locked in place in the connector. Such assembly is time consuming and inconvenient, especially where it occurs in the field. A connector with a contact that could easily terminate to a wire such as the inner conductor of a coaxial cable, as well as easily terminating to the rest of the cable, would be of value.

In accordance with one embodiment of the present invention, an electrical connector is provided which can terminate to a wire or conductor, such as the inner conductor of a coaxial cable, by inserting the conductor forwardly into the connector housing. The connector includes a coupling assembly comprising a contact with a mateable end at the front end of the housing, and also comprising a coupling. The coupling is formed of sheet metal and has arms with jaws that can engage the conductor to terminate to it. The arms are resiliently deflected apart to a ready position, and held in that position by a holder member. When the conductor is inserted, the arms and their jaws are released from the holder member to allow the jaws to clamp to the conductor to terminate to it. The arms are preferably suddenly released to create a "snap" that indicates such termination. The coupling assembly, which includes the contact and the coupling that has the arms with jaws, its preferably slidably mounted within the housing. As a result, when the conductor is inserted, it pushes against a surface of the coupling to move it forwardly. A conductor that is part of a coaxial cable holds the contact in its forward position, with an inner insulation that surrounds the conductor being fixed in position within the housing by crimping to the rear of the housing and by also crimping to a cable outer insulation at a location rearward of the housing. Such crimping occurs when a metal ferrule is placed around the coaxial cable outer conductor as it lies around the housing.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings.

FIG. 1 is a sectional view taken along the axis of a coaxial connector constructed in accordance with the present invention, shown in an unterminated, ready state.

FIG. 2 is a sectional view similar to that of FIG. 1, but showing the connector terminated to a coaxial cable.

FIG. 3 is an isometric view of the connector of FIG. 1, in the unterminated, ready state.

FIG. 4 is an enlarged isometric view of a portion of the connector of FIG. 3, shown in the ready state.

FIG. 5 is an isometric view of the connector of FIG. 2, shown in the terminated, released state.

FIG. 6 is an enlarged view of a portion of the connector of FIG. 5 in the terminated, released state.

FIG. 7 is a view of a portion of FIG. 1, showing the coupling in its ready position, and showing, in phantom lines, the coupling in its terminated position.

FIG. 1 illustrates an electrical connector 10 that has a substantially cylindrical metal housing 12 with a coupling nut 14. A rear portion 15 of the housing has radial outer projections 16 which help retain a screen braid outer conductor of a coaxial cable, as will be described later. A flange at 18 forms an abutment 20 to aid in mounting the connector. A sealing O-ring 22 lies in a radial groove in the body immediately rearward R of the flange. The forward end portion of the body includes a front sealing ring 24 that lies in a radial groove. A radial undercut 26 lying forward of the flange acts to retain the nut 14, the nut being rotatably mounted on the front portion of the housing and the rear end of the nut being swaged into the undercut 26. The front end of the housing is open and has an internal thread for connection to a mating connector device 28 with a socket contact 29, these being shown in phantom lines.

The connector has a bore 29 that extends forwardly into the rear end of the housing. A holder member 54 and an insulator 30 lie in the housing, with the holder member 54 having a through bore 56 extending from the bore 28 at the rear of the housing to a cavity 36 in the insulator.

A coupling assembly 35 which lies in the housing, includes a mateable contact 32, which is shown as being a pin contact with a mateable end 33 lying in the open front end of the housing in the coupling nut 14 thereof. The contact 32 lies at least partially in the housing front end, with the term "at least partially" meaning that either the entire contact lies in the housing or only part of the contact lies in the housing. The coupling assembly also includes a wire or conductor-terminating coupling 34 which is connected to the mateable contact 32. The coupling 34 lies in the cavity 36. The coupling is largely similar in appearance and operation to a "bulldog" clip, and has jaws 48 that can grasp an inserted conductor. FIG. 7 shows, in phantom lines, a cable conductor, central conductor 66 engaged by the coupling 34.

FIG. 4 shows that the coupling 34 is formed of sheet metal, and includes a base 52 extending largely perpendicular to an axis 37. The coupling includes a pair of longitudinally (along direction M) spaced arms 38, 40 extending from bends 50 at the top and bottom of the base. The coupling is symmetrical about a horizontal plane 51, with each arm having a pair of slots that form laterally (along direction L) spaced fingers including two positioning fingers 42, 44 and a jaw finger 46 between them. Each of the positioning fingers is bent to extend partially radially outwardly from the axis 37 in the ready position shown, while the jaw finger 46 extends towards the axis 37. The jaw finger 46 has a radially inner-rearward end forming a jaw 48. The term "jaw" is used only to indicate that the finger end forming the jaw 48 is intended to firmly engage a conductor. Each arm such as 40 has a proximal end 67 that joins to the base 52 through the bend 50, and has a distal end portion 68 that forms the slots that form the three fingers. As a result, when the positioning fingers 42, 44 are resiliently deflected away from the axis 37, the jaw finger 46 is also deflected away from the axis. The holder member 54 has a pair of projections or parts 58, 60 with surfaces 63 that hold the arms apart and away from the axis 37 in an unterminated or ready position of the connector.

FIG. 6 shows the coupling 34 after a wire or conductor 66 has been pushed forwardly F through the bore in the holder member 54, and against the coupling 34. Forward thrusting of the conductor 66 causes the coupling 34 to move forwardly, resulting in the positioning fingers 42, 44 being released from the holder member projections. This allows the jaw fingers 46 to move toward the axis 37 so the inner ends of the fingers, or jaws 48 engage the conductor 66. It is noted that the holder projections 58, 60 have tapered forward holder surfaces 62. Such tapered holder surfaces allow disengagement of the coupling 34 from the conductor 66, by forcefully pushing the coupling 34 forwardly, as by pushing the contact 32 forwardly. This is more easily accomplished where the coupling 34 and contact 32 are rigidly fixed together instead of being slidably electrically connected together. Once the radially inner end 69 of a positioning finger reaches the tapered surfaces, the arms rapidly move themselves toward the axis, creating a "snap" that is heard and felt. The jaws 48 then provide secure electrically conductive engagement with the conductor 66.

FIG. 7 shows the coupling 34 in its ready position in solid lines. The conductor 66 is shown in phantom lines after it has been thrust forward to move the coupling to its terminated position at 34A. It can be seen that the front end 56F of the bore 56 in the holder member 54 closely surrounds the conductor of predetermined diameter A (the difference in their diameters is preferably less than 0.5 mm) to avoid collapse of the conductor when rearward forces are applied to it during mating of the contact 32.

FIG. 2 illustrates a coaxial cable 71 with its central conductor 66 terminated to the coupling 34. The cable includes an inner cable insulator 72 that surrounds the central conductor 66, a braided screen outer cable terminal 67, and an outer insulator 74 that surrounds the outer cable terminal 67. To terminate the coaxial cable 71 to the connector 10, the forward cable end portion is prepared by stripping away different parts as shown, and with the outer terminal 67 usually spread backward around the outer insulator 74. The cable is then inserted into the bore 28 of the housing, with the conductor 66 guided in movement through the tapered through bore 56 of the holder 54, and against an abutting surface 76 on the coupling assembly. The technician pushes the cable forwardly at least until he hears or feels a snap. When the coupling 34 disengages from the holder member 54 and engages the conductor, the coupling continues forwardly until it encounters the front walls 76 of the cavity in the insulator 30.

After the central conductor 66 has been terminated to the coupling 34, the braided outer cable terminal 67 is spread around the housing rear portion 15. A ferrule assembly 69 comprising a tubular seal 70 with a metal ferrule 73 thereabout, is placed to lie around the housing rear portion 15 and extends rearwardly thereof. The metal ferrule 73 is then crimped, both at a location immediately around the housing rear portion 15, and at a location rearward thereof. The crimping at a rearward location at 75, causes the tubular seal 70 to bite into the outer insulator 74. The crimping of the metal ferrule 73 through the seal 70 to the housing rear portion 15 and to the outer insulator 74 assures a reliable connection of the coaxial cable to the housing.

As shown in FIG. 1, the pin contact 32 is slidably received in a narrow passage 78 of the insulator 30 of the housing, to slidably mount the coupling assembly to the housing. Any rearward R force on the contact mating end 33 is resisted by the central conductor 66.

The construction of the connector illustrated in the figures, enables termination of the central conductor 66 in a closed space (the cavity of the insulator 30) by simply pushing the cable forwardly into place. This makes termination very simple and results in the termination area being isolated from the environment. Release of the termination is also easily accomplished. It would be possible to have the coupling assembly 35 constructed so it is fixed in position, and have the holder member 54 slide along the axis, such as rearwardly, to allow the jaws to engage the conductor. In that case, the holder member would have a surface adjacent to the axis to allow a cable conductor to move the holder member forwardly to disengage it from at least one coupling arm that has a jaw. It also would be possible to have a holder member that slides perpendicular to the forward and rearward directions to release the jaw fingers, or even to have a holder member that turns to release the arms. However, in most cases such movement of the holder member would require additional steps and possibly access holes to move the holder member.

It would be possible to use more than two jaws, or even a single jaw that moves against the conductor while a nonmoveable support lies at a side of the conductor opposite to the jaw. However, applicant's use of a plurality of jaws increases the number of contacts and results in forces applied symmetrically about the conductor.

While the connector is shown for use in terminating a coaxial cable, it is possible to use the same invention to terminate to conductors or wires that are parts of cable (with one or more wires) that are not coaxial cables.

Thus, the invention provides a connector that allows termination to a conductor in a simple manner. The connector includes a coupling assembly with jaws that are resiliently deflected away from an axis along which the conductor is inserted, with the jaws then being released to engage the conductor. The coupling assembly can include a coupling formed from a piece of resilient sheet metal that includes a base extending primarily normal to the axis along which the conductor is inserted, and with a plurality of arms that are biased towards to the final conductor position. A holder holds the arms radially outward, but the coupling and/or the holder, and preferably the coupling, is moveable by the conductor to disengage the arms from the holder and allow them to engage the conductor in a snap action. The holder has surfaces positioned to spread apart the arms when the terminated coupling assembly is forced rearwardly.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.