Background of the Invention
This invention relates to an electrical connector assembly for connection to a coaxial cable and more particularly to an assembly in which the outer conductive shield of the cable is attached to the connector housing by an outer sleeve.
The attachment of coaxial cables to electrical connectors has often involved a variety of attachment techniques. In one technique, the outer shield of the cable is slid over a rear ferrule of the connector housing with the inner conductor and insulating member of the cable being inserted in a passageway in the ferrule and the conductor being attached to a center contact supported in the housing. An outer sleeve is slid over the shield and ferrule and crimped to force the shield against the ferrule. Often special crimping tools or apparatus have been required to provide a satisfactory attachment and reduce the possibility of damage to the ferrule. In another attachment technique, a nut or similar rotational member is rotationally coupled to a rear member of the connector housing forcing the shield to be confined between two surfaces in the housing. In some instances, a number of connector parts are required to isolate the rotational movement of the nut from the surfaces being forced against the shield.
Summary of the Invention
The present invention is directed to providing an improved connector assembly in which attachment of the assembly to a coaxial cable does not require the use of special crimping tools or a rotational coupling member. The connector assembly of the invention includes a connector housing with a tubular member or ferrule provided with an outer peripheral surface portion to receive the outer shield of the cable and a pair of raised portions axially separated by the peripheral surface portion and advantageously extending transversely about the ferrule for capturing an outer expandable sleeve. The sleeve is formed with a resilient outwardly expandable section which after movement over the rear raised portion contracts to press the shield against the ferrule. In the attachment technique of the invention, the outer shield of the cable is moved axially over the rear raised portion to reach a position over the outer peripheral surface portion of the ferrule. The outer sleeve is then moved axially over the raised portion until the resilient section of the sleeve resiliently closes inwardly against the peripheral surface portion to secure the shield against the ferrule.
The inventive connector assembly advantageously further provides the rear raised portion in the form of a barb with a tapered surface extending from a rear position radially outwardly and frontwardly to the outer dimension of the barb as a guide means for expanding the resilient section of the sleeve over one of the outwardly raised portions. Advantageously, the resilient section of the sleeve includes at least one longitudinal slit to form a plurality of outwardly expandable resilient members preferably in the form of resilient fingers with rear free ends.
Another embodiment of the connector assembly of the invention includes an enlarged front member joined to the rear ferrule by a radial flange and inwardly supporting a center contact. The outer shield of the cable is radially folded to extend against the flange and the outer sleeve is formed with a front radial flange. By the attachment of the outer sleeve between the rear barb and radial flange of the connector housing, engagement of the resilient fingers with the inwardly tapered shield and outer jacket causes the sleeve to be forced axially frontwardly to press the shield against the radial flange of the housing in addition to the outer peripheral surface portion of the ferrule.
In yet another embodiment of the invention, a front coupling ring is retained on the enlarged forward member by a front raised projection and rearwardly by the radial flange of the sleeve for limiting axial movement of the ring.
The resultant connector assembly provides several advantages. One advantage is that the outer conductive shield is attached to a rear ferrule without the use of special crimping tools. Another advantage involves the attachment of the outer shield to the ferrule without damage to the ferrule. A further advantage involves attachment of the outer shield to the rear ferrule by an axial movement without any significant rotational movement. Yet another advantage involves the attachment of an outer shield against a plurality of surfaces in transverse planes to reduce any tendency of the cable to move or creep after attachment. Still another advantage involves a connector housing in which a rear stop or mounting abutment for the coupling ring is insertable after the ring is mounted and is in turn retained by a rear stop or abutment shoulder.
Description of the Drawings
FIG. 1 is a side view of one embodiment of the connector assembly of the invention.
FIG. 2 is a sectional view along line 2--2 of FIG. 1.
Description of the Preferred Embodiments
In the preferred embodiment, the connector assembly of the invention is illustrated as a plug or male member since plugs are frequently attached to cables in the field and connected to female connector members mounted on various types of electrical and electronic equipment. However, it is understood that the invention is not restricted to connector plugs. The electrical connector assembly of the invention is provided for connection to a coaxial cable including an outer conductor with an inner surface portion, an inner conductor, and an insulating member separating the outer and inner conductors; with the assembly including a connector housing having an axially extending rear tubular metallic member with an outer peripheral surface portion dimensioned to engage the inner surface portion of the outer conductor and an inner passageway dimensioned to receive the inner conductor and insulating member. Contact means are supported in a housing and first and second outer raised portions are spaced apart along the axis of the tubular member and separated by the outer peripheral surface portion on the rear tubular metallic member. A sleeve member includes an outwardly expandable resilient section expandable to move over one of the outer raised portions and the outer conductor to be disposed over said outer peripheral surface portion. After movement over the one raised portion, the resilient section closes inwardly towards its normal inner dimension to press the outer conductor against the outer peripheral surface portion. The invention advantageously utilizes a coupling ring disposed frontwardly on the connector housing and third and fourth outwardly raised portions supported by the sleeve and connector housing for axial retention of the coupling ring.
In the method of connecting the coaxial cable to the connector assembly of the invention, first and second outwardly raised portions are spaced apart axially on the tubular member and an outer peripheral surface portion is positioned between the raised portions. The shield on the coaxial cable is inserted over the first raised portion and disposed over the outer peripheral surface portion with the inner conductor and insulating member of the coaxial cable being positioned within the tubular member of the connector housing. Prior to disposing the shield over the outer peripheral surface, an outer sleeve having a rear outwardly expandable resilient section is slid rear end first over the cable, and disposition of the shield over the outer peripheral surface portion, the sleeve is slid in the opposite direction axially over the cable with the tubular member therein to a location beyond the first raised portion to axially reach a location over the outer peripheral surface portion with the resilient section thereafter compacting to press the shield against the outer peripheral surface portion and the sleeve being axially captured between the raised portions and the intervening cable material.
As illustrated in FIGS. 1 and 2, the coaxial cable 10 includes a tubular outer conductive shield formed as a braid 12 and outwardly expandable, an inner conductor 14 extending along the axis 15 of the cable, an inner insulating member 16 separating the shield and inner conductor and an outer insulating jacket 18. The connector housing 20 is advantageously constructed of a conductive material such as brass and includes a rear tubular member 22 dimensioned to outwardly receive shield 12 and outer jacket 18 and having a passageway 23 inwardly dimensioned to permit passage of the inner conductor 14 and inner insulating member 16. Frontwardly on the connector housing 20 is front enlarged member 24 joined to rear member 22 by a shoulder formed by a radial flange 26. Coupling 28 is disposed about the enlarged member 24 for rotational coupling to a mating connector member (not shown).
Internally, the front enlarged member 24 includes an insulating insert 30 advantageously made of a plastic material and molded on inner contact 32 for support of the contact and secured in outer shell 34 by rolled or spun portion 36. Inner contact 32 is constructed of an electrically conductive material such as brass and includes a rear flared portion 38 to secure the contact against frontward movement and a radially folded portion 40 for securing the contact against rearward movement. Frontwardly contact 32 includes first and second tubular portions 42 and 44 respectively for attachment to inner conductor 14 and a mating socket contact (not shown) of a mating connector. Further, second tubular portion 44 serves to support and/or align inner insulating member 16 and the inner conductor 14 as illustrated in FIG. 2.
As illustrated in FIG. 2, tubular member 22 is provided with an outer peripheral surface portion 46 dimensioned to engage the inner surface portion 13 of shield 12. Advantageously, shield 12 is extended with a radial fold 48 and positioned against radial flange 26 to provide a plurality of surfaces in different planes for attachment of the shield against the connector housing. Longitudinally separated by the outer peripheral surface portion 46 are first shoulder or raised portion 50 advantageously in the form of a barb and the aforementioned shoulder or second raised portion advantageously in the form of radial flange 26.
Means for securing shield 12 to rear tubular member 22 is illustrated in the form of an outer sleeve 52 shown in FIG. 2 as being captured between barb 50 and radial fold 48 pressed against radial flange 26. Advantageously, guide means are provided to guide sleeve 52 over barb 50 to reach the outer peripheral surface portion 46. As illustrated in FIG. 2, guide means 54 is advantageously in the form of a tapered surface 56 on barb 50 and is tapered frontwardly and outwardly at an acute angle preferably about 10 degrees with barb 50 being shaped with a sharp change in direction 55 to cause shield 12 to taper inwardly when forced inwardly by sleeve 52 thereby causing sleeve 52 to press radial fold 48 of shield 12 against radial flange 26 to secure shield 12 against outer peripheral surface portion 46 and radial flange 26.
Outer sleeve 52 is dimensioned to be moved axially along rear tubular member 22 and over barb 50, shield 12, and outer jacket 18 to reach a position over outer peripheral surface portion 46. A rear resilient section 58 formed to be outwardly expandable by movement over barb 50 is provided and normally dimensioned to press shield 12 against outer peripheral surface portion 46. Advantageously resilient section 58 includes at least one longitudinal slit 60 and preferably a plurality of slits to form a plurality of resilient fingers 62 having rear free ends 64.
Frontwardly on sleeve 52 is provided an outer radial flange 66 to press radial fold 48 against radial flange 26 and as enlarged radially beyond the outer dimension 25 of enlarged member 24 (as illustrated in FIG. 2) serves as a rear stop 68 for coupling ring 28. Enlarged member 24 includes a front portion 70 with a second raised projection 72 to the projection represented by flange 66 to provide a front stop 74 for a coupling ring 28.
As illustrated in FIG. 2, inner contact 32 is provided with first and second tubular members 42 and 44 for respectively securing inner conductor 14 to the contact and for engaging an external mating socket contact. Advantageously, first tubular member 42 is of reduced dimension 76 to the dimension 78 of second tubular member 44 and thereby can be crimped or peened to retain the center conductor 14 without deforming or changing the outer dimension 78 of second tubular member 44. In the attachment of the coaxial cable 10 to the connector housing 20, the shield represented by radial fold 48 is stripped of outer jacket 18 and rearwardly shield 12 and outer jacket 18 are separated from inner insulating member 16. The separated and stripped shield 12 is inserted over tapered surface 56 and outer dimension 57 advantageously shaped as an edge extending transversely around tubular member 22. Sleeve 52 is moved axially forward without significant rotational motion with finger 62 sliding over tapered surface 56 and resiliently closing inwardly against insulating jacket 18 to press shield 12 against outer peripheral surface portion 46 which further acts to cause flange 66 to press radial fold 48 of shield 12 against flange 26.
Upon positioning of sleeve 52, flange 66 provides a rear stop 68 for capturing coupling ring 28 in recess 75 formed by flange 66 and raised projection 72.
As an example of the dimension of barb 50 and sleeve 52 and not for limiting purposes, edge 59 may have a flat portion of approximately 0.002 inches with a frontwardly facing shoulder 80 of a radial dimension of about 0.010 inches with resilient fingers 62 being about 0.026 inches thick.
As described above movement of sleeve 52 axially into the recess 82 formed by barb 50 and flange 26 provides a means for securing shield 12 on rear tubular member 22 and further provides a portion of the retaining means for coupling ring 28 by third and fourth raised portions 66 and 72 in which both advantages are provided in mechanical operation not requiring complicated tools.