US3077513A

US3077513A - Coaxial cable connector

Info

Publication number: US3077513A
Application number: US838015A
Authority: US
Inventors: Gordon P Felts
Original assignee: Microdot Inc
Current assignee: Microdot Inc
Priority date: 1959-08-28
Filing date: 1959-08-28
Publication date: 1963-02-12
Anticipated expiration: 1980-02-12

Description

Feb. 12,1963 G. P. FELTS 3,07 5 3 COAXIAL CABLE CONNECTOR Original Filed Sept. 1, 1955 6 [4 "I I0 7/ 28 l l INVEN TOR. GORDON R FELTS United States Patent 3,677,516 QQAXKAL QAFS LE CGNIJELTQR Gordon Felts, Palm Springs, Calii, assignnr to Micro dot inc, s euth Pasadena, Calitl, a corporation of California Continuation of application Ser. No. dfifitld, Sept. 1, 1955. This applicati in Aug. 28, 195?, Ser. No. 838,015

Claims. (Ci. 174 75) This is a continuation of application Serial Number 531,905 (now abandoned), filed September 1, 1955, in the name of Gordon P. Felts for a Cable Fitting.

The present invention relates generally to cable fit tings, and is more particularly concerned with miniature connectors for insulated and shielded cables commonly known as coaxial cables.

The small size of these miniature connectors presents inherent manufacturing problems with respect to construction and assembly, which are not present in the production of connectors for cables of relatively larger sizes as heretofore commonly used. It is therefore not possible to follow the same techniques as were previously used in the fabrication of larger connectors for the construction of miniature connectors.

Having in mind these distinctions, the present invention has for an object the provision of miniature connectors in which certain of the component parts are so constructed that they will be automatically anchored upon movement of these parts to assembled position.

A further object is to provide in miniature connectors of the type described herein, a construction wherein larger tolerances may be utilized, thus facilitating assembly of the parts.

It is also an object to improve the design of miniature connectors so that longer leakage paths will be obtained, strains will be relieved and contact members will be kept in position and in better alignment than heretofore.

Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon.

Referring to the accompanying drawings, which are for illustrative purposes only:

FIGURE 1 is an enlarged longitudinal section through one part of a two part connector fitting embodying the features of the present invention, certain parts being shown in full lines, while other parts are cut away to disclose features of construction;

FlGURE 2 is an exploded View of certain of the component parts as used in the structure of FiGURE 1, these parts being shown in their initial form before assembly;

FIGURE 3 is an enlarged longitudinal section of a mating part of a two part fitting connector, this part being arranged for connection with the part disclosed in FIGURE 1; and

FlGURE 4- is a detail view of a bushing used in the part disclosed in FlGURE 3, this bushing being shown in its pro-assembly form.

Referring generally now to the drawings, for illustrative purposes only, there is disclosed in FIGURES 1 and 3 a plug fitting as generally indicated at A in PEG- URE 1, and a receptacle fitting as generally indicated at B in FlGURE 3, these fittings being adapted for interconnection and forming the mating parts of a two-part connector assembly.

The detailed construction of the plug A, as shown in FZGURE 1 will now be described. This fitting part comprises an elongate tubular outer conductor in the form of a ferrule id of electrical conducting material, this ferrule being adapted to receive through one end a coaxial cable having a conducting sheath l1 and in- Patented Feb. 12, tees sulated central conductor 12 of conventional construction. Associated with this end of the sheath It is a tubular bend relief cap l3 of elastic insulating material such as Teflon or other suitable material. The bend relief cap is interlocked with the associated end of the ferrule by means of a rib and groove connection, as generally indicated at E4.

At the opposite end of the ferrule it), there is provided a circumferentially extending end flange l5 which serves to retain a connection nut 16 on the ferrule and support it for turning movement to enable interconnection with a threaded end of the mating connector B shown in FIGURE 3, and which will subsequently be described in detail.

The end of the ferrule it) which is associated with the coaxial cable is provided with an internal conical wall portion 17 which is adapted to coact with an end 18 of a clamp ring 19. When the clamp ring is forced against the conical wall, a wedging action is produced which causes the ring to contract and clamp the sheath 11, thereby grounding it to the ferrule iii. The clamp ring also functions to electrically connect the cable sheath with the ferrule it) having the nut 16 thereon.

The central conductor 12 of the cable is brought out and positioned in a slot 20 formed in a head end 21 at one end of an elongate inner conductor providing a pin contact 22, the central conductor of the cable being soldered or otherwise anchored and secured within the slot 2% so as to retain the head portion 21 tightly in abutment with the adjacent end of the cable insulation.

An inner tubular bushing 23 of insulating elastic ma terial, such as that designated by E. I. du Pont de Nemours and Company under the trademark of Teflon, is constructed with a reduced bore portion 2a which on compasses the adjacent insulation of the coaxial cable which separates the central conductor and conducting sheath. An end section having an enlarged bore portion 25 is arranged to extend over and surround the periphery of the head portion 21 of the pin 22.

An outer bushing 26 is similarly constructed of a ma terial such as Teflon, this bushing also being provide with a reduced bore portion 27 which is mounted in closely gripping relation around the portion of the pin 22 adjacent the head 21 so as to abut the head 21 along the length of the head. The outer bushing has an enlarged bore portion 23 which is adapted to extend over the outer surface of the inner bushing 21$. The innermost ends of the inner and outer bushings bear against end portions of the cable sheath H which are carried out between the ends of the inner and outer bushings and the adjacent end of clamp ring 19. The inner and outer bushings cooperate with the insulation of the coaxial cable to completely enclose the head portion of the pin 22 and form circumambient layers of insulation about the head 21 so as to provide long leakage paths. The insertion of the

bushings

23 and 26 on the head 21 of the pin 22 and into the bore of the ferrule it? facilitates the wedging of the clamp ring 19 against the ferrule in.

T his end of the ferrule 16 has its internal bore wall provided with an inwardly tapered end portion 25? which terminates at its innermost end in a radial circumferential extending shoulder 31% which coacts with the outer surface of the outer bushing to retain the pin and inner bushing in assembled position with the pin 22 projecting beyond the adiacent end of the outer bushing to form a connection male member.

Referring to FIGURE 2, it will be noted that certain of the component parts of the connector of FIGURE 1 have a different configuration initially, the configuration being somewhat altered when the parts are in assembled relation. For example, the clamp ring 19 is initially sewers of uniform external diameter and is provided on its interior with threads 31 which facilitate its connection to the conductor sheath. The ring has a longitudinally extending slot 32 therein and a plurality of slots 33 which extend a portion of the length of the ring to define fingers so that the end of the clamp ring which engages the wall 17 and which defines the fingers may be deflected into clamping gripping engagement with the sheath of the cable when forced against the Wall 17. It will also be noted that the outer bushing 26 has its right end portion, as viewed in FIGURE 2, constructed with uniform external diameter, but that when the bushing is inserted endwise into assembled position within the right end of the ferrule it), as viewed in FIGURE 1, the bushing will be radially inwardly compressed as it passes the innermost end of the tapered bore portion 29, but as the bushing passes the shoulder 39, the material is relieved to expand outwardly and thus form an interlocking connection which prevents removal of the bushing 26. This results from the fact that the external dimensions of the outer bushing 26 are slightly greater than the dimensions of the internal bore wall in the ferrule it Referring now to FIGURE 3, the construction of the mating connector receptacle B will now be described.

This connector comprises a tubular housing 34 of electrical conducting material which, for purposes of illustration, is shown as being of the type adapted to be mounted on a bulkhead. The connector is arranged to be mounted in position by inserting a threaded end 35 thereof through a suitable bulkhead opening, the fitting being secured clampingly by means of an abutment flange '36 and a nut 37 in threaded engagement with this end of the tubular housing. The opposite end of the housing is also threaded as indicated at 38 to receive the connection nut 16 of the fitting A, a gasket 39 being provided against which the nut 16 may be screwed in order to form a sealed connection and electrically connect the cable sheath 11 with the housing 34. The housing 34 is likewise in electrical connection with a lug connector 39' of conventional construction.

The pin 22 is adapted to make connection with an end socket 4d of a central conductor 41 which is also provided at its opposite end with a similar end socket 42. Between its ends, the central conductor is formed with a series of serrations 43 which provide an undulated surface on the central conductor 41.

The central conductor 41 is retained in assembled axially extending position by means of a tubular elongate bushing 45 which is shown in FIGURE 4 as having a uniform external diameter except for a tapered end portion 46, and a uniform bore passage 47 terminating in a beveled edge opening it; at its tapered end. This beveled edge opening 4% permits the bushing to be inserted endwise over the central conductor 41, and in so doing, the material of the bushing is slightly radially compressed so that in the final assembly position, the central portion of the bushing bore 47 is relieved and is permitted to expand into the serrations 43 and thus interlock with this undulated surface to retain the bushing and central conductor in assembled relation.

Referring again to FIGURE 3, it will be noted that the left end of the tubular housing 34 is internally provided with an inwardly tapered conical bore wall 49 which terminates at its innermost end in a radial circumferentially extending shoulder t). At the opposite end of the tubular housing 34, the bore of the housing is formed with an internal end rib 51 which defines a reduced bore passage which terminates at the innermost end of the rib in a radially extending circumferential shoulder 52.

The bushing 45 with the central conductor assembled therein is assembled in the housing 34 by inserting the tapered end dd of the bushing endwise into the left end of the housing, as seen in FIGURE As the bushing is pushed through the bore of the housing 34 until final assembled position as shown in FIGURE 3 is reached, the material of the bushing will be radially compressed as it passes the restricted end of the tapered bore wall 49, and the rib 51. However, in the bore portion lying between the

shoulders

50 and 52, the periphery of the bushing 45 is relieved so that it may expand outwardly and thus interlock the bushing 45 with the housing 34 against movement longitudinally in opposite directions. With this arrangement, it will be noted that the parts are interlocked in assembled relation as soon as the parts are moved into their final assembly position.

It is thus possible to eliminate the close tolerances ordinarily used in construction of fittings of this type .and utilize a technique of improved character for the production of miniature connectors.

Various modifications may suggest themselves to those skilled in the art without departing from the spirit of my invention, and, hence, I do not wish to be restricted to the specific form shown or uses mentioned, except to the extent indicated in the appended claims.

.I claim:

1. A fitting for a cable having a central conductor and an outer conducting sheath and insulation between the central conductor and the sheath, comprising: a tubular housing having a central bore and coupled at one end to said cable and made from a conductive material, said housing having a beveled internal wall adjacent its cable receiving end; a clamp ring within the central bore of said housing and surrounding and engaging the sheath of said cable and made from an electrically conducting material, said ring having at least one finger being clamped against said sheath and electrically grounded to said housing, when the finger on the ring is forced against said beveled wall; a contact pin having a head end abutting an end of the cable insulation, said head end being slotted to receive the central conductor of the cable therethrough; means anchoring the conductor in said slot; an inner insulating bushing surrounding the head of said pin and adjacent cable insulation; and an outer insulating bushing surrounding said pin and said inner bushing along the length of the head end of the pin, the inner ends of said inner and outer insulating bushings bearing against an end portion of the cable sheath carried out between said bushing ends and the adjacent end of said ring; and confronting interlocking surfaces on said outer bushing and the central bore of said housing for retaining said parts in assembled position with the pin end opposite its head end projecting from the outer bushing to form a male connection contact.

2. A fitting for a cable having a central conductor and an outer conducting sheath and insulation between the central conductor and the outer sheath, comprising: a tubular housing having an internal bore and receiving an end of said cable through said bore, the bore of said housing being defined by a beveled internal wall adjacent its cable receiving end, the housing being made from electrically conductive material; a clamp ring within the bore of said housing and having at one end a finger engaging the sheath of said cable, the finger of said ring being clamped against said sheath and electrically grounded to said housing and to said sheath of said cable, when the finger on said ring is forced against said beveled wall; a contact pin having a head end abutting an end of the cable insulation; means securing the central conductor of said cable to said head end of said contact pin; a first insulating bushing surrounding the cable insulation on one side of said head; a second insulating bushing surrounding the pin on the opposite side of said head and having an outer dimension greater than the internal dimension of the bore in the housing, said bushings having overlapped adjacent end portions circumambient of said head; and shoulder means on the outer surface of said second bushing and in the internal bore of said housing to hold said second bushing in assembled position relative to the housing for retaining said pin and first bushing in assembled positions.

3. A fitting for a cable having a central conductor and an outer conducting sheath and insulation between the central conductor and the sheath, comprising: a tubular housing made from an electrically conductive material and having an internal bore to receive an end of said cable through one end, the bore in said housing being defined by a beveled internal wall adjacent its cable receiving end and by an inwardly tapered bore wall at its opposite end terminating in a circumferential shoulder; a clamp ring within said housing and made from an electrically conductive material and having at one end at least one finger having a tapered external configuration and engaging the sheath of said cable, the finger on said ring being clamped against said sheath and against the beveled internal bore wall of the tubular housing and electrically grounded to said housing when the finger on said ring is forced against said beveled wall; a contact pin having an enlarged head end abutting an end of the cable insulation; means securing the central conductor of said cable to said head end; a first insulating bushing surrounding the cable insulation on one side of said head; and a second insulating bushing surrounding the pin on the opposite side of said head, said bushings having overlapped adjacent end portions along the length of said head, the outer dimensions of said second bushing being greater than the dimensions of the bore in the housing, said second bushing in assembled position being expanded outwardly against said radial flange in the bore of the housing to lock the second bushing in assembled position relative to the housing and retain the pin and first bushing in place.

4. In combination in an electrical connector for use with a cable having an inner conductor, an outer conductive braid and insulating material between the inner conductor and the outer braid: a clamp ring made from electrically conductive material and disposed on the outer conductive braid of the cable in electrical contact with the braid and provided with fingers movably disposed to become pressed against the outer conductive braid of the cable, a ferrule made from electrically conductive material and disposed on the clamp ring in electrical contact with the clamp ring and provided at its inner periphery with a bore having a tapered configuration to press the fingers of the clamp ring against the outer conductive braid of the cable to obtain electrical continuity between the ferrule and the outer conductive braid of the cable, insulating sleeve means disposed in cooperative relationship with the ferrule Within the bore in the ferrule and provided with properties of physical deformity under pres sure and with dimensions greater than those of the bore in the felrule to form an interlocking relationship with the ferrule, and means including a pin disposed in electrically coupled relationship to the inner conductor of the cable and in cooperative relationship with the sleeve means to facilitate the deforming of the sleeve means into interlocking relationship with the ferrule.

References Cited in the file of this patent UNITED STATES PATENTS 2,397,735 Grieb Apr. 2,1946 2,563,712 Frei et al. Aug. 7, 1951 2,563,762 Uline et a1 Aug. 7, 1951 2,603,682 Uline et a1 July 15, 1952 2,615,953 Waite Oct. 28, 1952 2,757,351 Klostermann July 31, 1956 2,774,812 Clark Dec. 18, 1956 2,785,385 Figueira Mar. 12, 1957 2,839,595 Felts et al. June 17, 1958 2,870,520 Malek Ian. 20, 1959 FOREIGN PATENTS 460,156 Great Britain Jan. 22, 1937