US3158823A

US3158823A - Coaxial line coupling and partition device

Info

Publication number: US3158823A
Application number: US844933A
Authority: US
Inventors: James R Bird; Blossy D Frederico; Herbert H Heller
Original assignee: Bird Electronic Corp
Current assignee: Bird Electronic Corp
Priority date: 1954-10-04
Filing date: 1959-10-07
Publication date: 1964-11-24
Anticipated expiration: 1981-11-24
Also published as: GB823028A; GB823030A; GB823029A

Description

Nov. 24, 1964 J. R. BIRD ETAL 3,158,823

COAXIAL. LINE COUPLING AND PARTITION DEVICE Original Filed Oct. 4, 1954 2 Sheets-Sheet 1 INVENTORS. James E. Bird Biossg 0. Freder/to BY Herbert H. Heller Nov. 24, 1964 J. R. BIRD ETAL COAXIAL LINE COUPLING AND PARTITION DEVICE Original Filed Oct. 4, 1954 2 Sheets-Sheet 2 INVENTOR. James E 501/, fiiossy 0. Ereder/to. BY Herberl H. Heifer 309M, M bvw,

ATTORNEY-5.

United States Patent 3,158,323 CUAXHAL MINE QQUPLENG AND PARTETEGN DEVTCIE .latnes R. Bird, (Chagrin Falls, Blossy l). Frederiee, Cieveland, and Herbert H. Heiler, (Ilevelaud Heights, Shin, assigners to Bird Electronic Corporation, Solon, Ulric, a corporation of @hio Original application Oct. 4, i954, tier. No. 46%,(342, now Patent No. 2,958,830, dated Nov. 1, 196th. Divided and this application 0st. 7, 1959, $621. No. 844,933 18 Ciaims. (61. 333-22) This invention relates to connecting and partitioning structures useful, for example, in resistive terminations commonly known as dummy loads for high frequency coaxial lines. A load customarily is designed for use with a coaxial line of specific impedance and preferably is arranged to have an input impedance which, over a large range of frequencies, is equal to the characteristic impedanceof such line. Reference is made to copending application Serial No. 460,042 filed October 4, 1954, now Patent 2,958,830 dated November 1, 1960 for Coaxial Line Load Device, of which this is a division. Such a load may comprise an attenuating line section including an outer sleeve conductor tapered inwardly to its rear end and an inner conductor coaxially mounted within the sleeve and joined thereto at its rear end. The inner conductor is resistive in character, may be in the form of a thin resistive coating on a ceramic core. The load or attenuating line section is enclosed in a suitable housing filled with a liquid dielectric and the tapered outer conductor is perforated or slotted to allow the liquid dielectric, serving also as a coolant, to be in continuous contact or heat exchanging relation with the inner conductor. The housing containing the bath of liquid dielectric may be cooled by radiant or convective loss of heat to the atmosphere, or, where high power absorption and dissipation is desired, by a circulated refrigerant.

The principal object of the invention is to provide a fluid tight insulating coupling or connection for very high frequency equipment disposed within a housing containing fluid whereby connection may be made to an external coaxial line with low losses and with little disturbance of the line characteristics and in a manner precluding loss of fluid from the housing.

In accordance with the invention, the tapered attenuating line section is immersed in a liquid dielectric coolant contained in a metal housing so shaped as to promote improved convective flow of the coolant. The attenuating line section is projected into the housing interior through an opening adjacent the bottom of one end wall of the housing and is supported by such housing wall. Thus the line section is located close to the bottom wall of the housing and with its axis substantially parallel thereto. The attenuating line section is sealed into the housingthrough a bush or washer made of a low loss dielectric or insulating material such as polytetraiiuoroethylone or a compound known commercially as Teflon. The seals to the washer are made of narrow sections with undercut sealing surfaces whereby to achieve both a mechanical interlock and a tight seal, despite the cold-iiow characteristics of the material of the insulator.

At the input end of the line section is an annular conducting ring which is a part of or is sealed to the container and is in contact with the outer conductor or a fitting coupled to it, and an annular insulating bush which is Within the ring and around the inner conductor or a fitting coupled to it, the bush being sealed and mechanically held against axial movement in relation to the inner conductor or fitting and the annular conducting ring, whereby the ring and bush comprise a closure for the container opening. The device includes means for coupling the attenuating unit to a coaxial line of which the outer conductor can make contact with the annular conducting ring or a fitting coupled to it and the inner conductor can make contact with the inner conductor of the unit or a fitting coupled to it.

The annular conducting ring may have a recess for the accommodation of one end of the outer conductor of a coaxial line, or a member secured to it, while the insulator or bush may be sealed around a fitting coupled to the inner conductor of the unit which fitting comprises a standard plug or socket fitting for connection to the inner conductor of a coaxial line.

For further objects and advantages and for a better understanding of the invention, attention is now directed to an illustrative embodiment representing the best known mode of practicing the invention, as set forth in the following description and as shown in the accompanying drawings forming a part of this specification. The features believed to be novel will be more particularly pointed out in the appended claims.

in the drawings:

FIGURE 1 is an elevation partly in section of an attenuator in the form of a refiectionless termination unit connected to a coaxial line through a coupling embodying the invention;

FIGURE 2 is a detail partly in section of a part of FIGURE 1 to a larger scale, and

FIG. 3 is a fragmentary enlargement of a portion of FIG. 2 showing the interlocking of the inner and outer peripheries of the insulating partition with the inner and outer conductors of a coaxial line system.

Referring to the drawings, there is shown a load device 1 comprising a generally rectangular housing 2 which serves. as a reservoir or tank for liquid dielectric 3 in which an attenuating line section 4 of the tapered horn type is immersed. The liquid dielectric coolant may be any suitable liquid such as that available commercially as Dowtherm A. The housing may be made of sheet material such as steel, copper, brass, aluminum or the like. Material of good heat conductivity is desirable and in general brass or copper are preferred because of the case of soldering and brazing thereto. The housing may be formed of a sheet of brass bent with corners to form main side walls and top and bottom walls abutted edges being welded in a medial seam in the center of the top wall.

End walls

11, 12 are fastened by welding in the corners to make a fluid-tight enclosure.

The attenuating line section 4 is accommodated in the lower part of the housing close to the bottom wall and with its axis substantially parallel thereto. The attenuating line section comprises a hollow horn or shell 16 which is of tubular form tapering inwardly to its rear end 17. This horn surrounds the inner or resistive conductor 18 in coaxial relation and is preferably tapered exponentially. The inner conductor may comprise a ceramic tube 1% coated with a layer of a resistive coating 21 sufiiciently thin to eliminate skin effect in relation to currents flowing thereto throughout the range of frequencies for which the device is designed. The coating 21 may be in the form of carbon, tungsten, platinum or other metal applied by vacuum vaporization, sputtering, painting in colloid dispersion, electrolytic deposition, or other known methods. The outer tapered conductor 16 is perforated as indicated at 22 to allow the circulation of the liquid dielectric 3 therethrough; these perforations may be in the form of longitudinal slots, preferably all along the topsurface but only adjacent the small end in the bottom surface of the horn shaped conductor.

The outer tapered conductor 16 is formed at'its large diameter end with an integral cylindrical portion 10 fastened peripherally to a mounting ring 23 over which it is telescoped and which may be made of brass or other relatively soft metal. The fastening may be by soldering or, if desired, by mechanical means such as screws placed around the periphery of the ring. The ring 23 has a rearwardly inclined outer flange 24 at its forward end, this flange being juxtaposed to a forwardly inclined outwardly directed radial flange 25 at the forward end of a fastening ring 26. The fastening ring 2:: is externally milled or otherwise cut away at its inner end to obtain a squared or other non-circular cross section received matingly and non-rotatively within the matching opening in the upright front wall 11 of the housing. The milling also provides a radial shoulder 27 on the mounting ring which is disposed flatwise against the outside of the housing and is fastened hermetically thereto, preferably by welding or brazing as indicated at 2.8. The milling or cutting away of the inner end of the mounting ring 26 at circumferentially spaced regions to provide the noncircular shape mentioned results in a plurality of circumferentially spaced arcuate segments 26a which are integral with the body of the mounting ring, project through the housing opening into the housing interior and embrace the cylindrical portion ill of the conductor 16. In the embodiment of the invention presently contemplated there are four of the segments 26a, two of them being shown in broken lines in FIG. 2. These segments guide the attenuating line section in assembly and support it over a substantial portion of its length to prevent Wobbling of the line in the housing. The body portion of the mounting ring 23 makes a snug sliding fit within the embracing fastening ring 26 and the two are held together by means of a constricting clamping ring 29. The clamping ring is V-shaped in cross section to engage the inclined radial flange portions 24 and 25 and draw them together. An ring 31 made of soft resilient compressible material, not affected by the dielectric fluid within the housing, for instance, a rubber-like sealing gasket material, is located between the flange portions 24 and 25. As the clamping ring is tightened circumferentially as by means of screw 32 (FIG. 1), the C; ring washer is compressed and a hermetic seal is achieved.

The outer tapered conductor is and the inner conductor 13 are located in spaced relation at their front end by means of an insulating washer 33 made of a low loss dielectric material such as the compound polytetrafluoroethylene known commercially as Teflon. The rear outer edge of the spacer 33 is circumferentially rabbeted at 34 to provide a shoulder 33a, which shoulder abuts against face 30 of an inwardly directed thin shallow flange 35 on the rear end of the mounting ring 23. The mating face 30 of the circumferential flange 35 and the radial shoulder 33a of the insulator 33 or one of them, are inclined slightly off the radial in the direction obtaining an undercutting of the shoulder on the partition washer 33 in order to produce a locking effect when the insulator is squeezed axially in the manner now to be described.

The structure of the outer conductor for coupling the load device to the end of a transmission line comprises a tubular cylindrical member or portion 35 having at its outer or free end the usual very high frequency bolting flange 37, an intermediate branch line coupling member or portion 38 in the form of a cylindrical tube and a thermal insulating member or portion 39 also in the form of a cylindrical tube. The inner end of the cylindrical tube member 39 is provided with a contact ring 41 preferably made of brass and brazed thereto. The ring 41 is rabbeted internally to receive the end of the tube member 39 in a sliding fit in assembly, the abutment of the tube against the bottom of the rabbet serving to locate the tube in predetermined position in the ring. The forward or outer end of the mounting ring 2-3 is counterbored and internally threaded to receive a spanner type ring screw 42 provided at its inner end with an internal circumferential rabbet in which is accommodated a split Washer or ring spacer 43, preferably made of hard metal as steel. The internal diameter of the ring 42 is greater than the external diameter of the thin thermal barrier member 39 in the provision of an annular clearance 5t) therebetween. When the ring screw 42 is tightenec, the spacer ring 43 is forced axially against radial end face it? of the contact ring 41 which, being fast to the external conductor of the coupling structure locks the line in position. Inner end face 6 of the contact ring 41 engages the circumferentially extending outer edge portion of the insulating washer 33 and causes outer periphery 4-4 of the partition washer to be squeezed between the inward flange 35 on the mounting ring 23 and the rear or inner face dd of the contact ring. The end face till is chamfered or inclined oppositely to the inclined face of the mounting ring flange 35. The partition washer is formed on its outer face 26 and at the juncture of the surfaces defining the rabbet 34 with grooves 45 extending circumferentially about the partition washer and located in underlying relation to the edge corners of the inclined faces on the flange 35 and the ring end 60.

' Thus the peripheral portion 44 of the partition Washer located radially outwardly of or beyond the stress relieving break grooves 45 is not only squeezed but, is also locked in dovetail fashion so that a fluid tight seal is maintained notwithstanding the cold-flow characteristics of the material of which the dielectric partition washer or spacer 33 is composed.

The inner conductive structure which connects to the resistive conductor 13 is sealed through the insulating partition 33 in the following fashion. The end of the ceramic core i9 is formed with a reduced diameter portion 46 and a thin conductive band of plated-on metal such as silver is applied over the end portion of the resistive coating ill and extends over the reduced diameter portion 46. The rear end of a circular sectional conductive plug 47, which may be made of brass, as by turning in a lathe, is formed with a tubular end extension 48 which is received telescopically and makes a snug fit over the reduced diameter portion 46 of the inner conductor, the overlapping portions being secured together by a conductive cement. Further to assure good electrical conductivity at the joint, a band of solder 49 is placed to overlap tubular extension it; and the plated-on metal contact band of the inner conductor 18. The diameter of the plug 47 is the same as that of the inner conductor 13 whereby to effect a smooth unbroken surface between the parts that constitute the inner conductor of the attenuating line section. The plug 47 is provided with an external undercut or inclined circumferential shoulder 51. This shoulder is formed by machining a reduced diameter portion on the plug, by providing a flange, or, as shown, by both a reduced diameter portion and a shallow radial flange. inclined end face 52 of an external mounting cap or ring 53 cooperates with the plug shoulder 51 to compress axially an internal radially projecting and circumferentially continuous lip portion 54 or" the insulating spacer or partition 33. The parts are drawn together axially by tightening bolt 55 which passes through a central opening in the cap 53 and is threaded axially into the end of the plug 4"]. This end of the plug is reduced in diameter to provide a pilot 66 which is received telescopically within a socket 6'7 drilled into the cap 53, thereby establishing axial alignment of the parts. The socketed end of the cap has a reduced diameter end received snugly and locatingly within the counterbore in the partition member 33 which is adjacent the annular lip 54 and a deformable Teflon washer or ring 7% embraces the cap and is confined between the front face 29 of the partition 33 and annular shoulder '71 on the cap 5'3. The internal annular lip 54 is formed with undercut and circumferentially grooved side walls whereby to relieve the strain in the material when the lip is under axial compression between the inclined annular compression surfaces of the shoulder 51 and the cap end face 52. The undercut side walls and the circumferential grooves are indicated in FIG. 3 at 68 and 69, respectively. The lip 54 thus is squeezed in dovetail fashion whereby to provide a locking effect. This results in a hermetical seal which is long-lasting in spite of the cold-flowcharacteristics of the insulating material.

The intermediate portion 39 of the outer conductor is made of material of relatively low thermal conductivity, such as stainless steel of the type, say, AISl type 302, and is relatively thin or shell-like in cross section. By reason of its high strength the 18% chromium, 8% nickel, iron alloy comprising the conductor portion 39 can be made extremely thin, of the order, say, of about .025 inch to about .060 inch at a diameter of 3 inches. Shown is nominal 18 gauge tube about .048 inch thick. The tubular outer member comprising the coupling line section 38 has internally rabbeted ends providing short cylindrical sockets or undercuts 56 and 57 which receive the ends of the tubular outer members comprising

conductor sections

39 and 36 respectively. The overlapping portions of the members are fastened together by suitable means such as brazing and there is thus provided a smooth unbroken interior surface of uniform diameter whereby to maintain the characteristic impedance unchanged throughout the coupling structure.

The outer conductor tube 38 of the branch coupling line section is provided with a detector mounting block 53 secured as by screws and brazing. The mounting block 53 is formed with a cylindrical socket that opens through a mating aperture in the outer conductor of the line so as to provide access to the annular dielectric space surrounding the center conductor. The mounting block 53 is adapted to receive a suitable voltage or other detecting or coupling device $4 for sampling the line voltage or energy at the input end of the attenuating line section load device. Electrical connections to the components of the pickup are made inside the mounting block 58, the leads being brought out through the side of the blockto a center terminal 85 and a threaded outer terminal boss 86 to which a galvanorneter or other suitable indicator (not shown) may be connected as by means of a coaxial cable having an appropriate end fitting for attachment to the boss 86.

Inner conductor 59 of the coupling line section is in the form of a cylindrical brass or other resilient metal tube. At its inner end this tube is formed with axial slots 88 in the provision of a multiplicity of axially directed fingers 39 that resiliently embrace the tapered head end of the mounting cap 53. Desirably the inner end of the conductor tube 59 is bored or internally relieved to reduce the thickness of the spring contact fingers 89. At its outer end the inner conductor tube 59 is supported on the large diameter end of a stepped plug 61 having a reduced or small diameter portion received through and supported in the center hole of a circular insulating disc 62 of polytetrafiuoroethylene or similar plastic material. The end of the conductor tube 5% which is received over the large diameter inner end of the plug 61 is counterbored in the provision of a circumferentially extending locating shoulder 90 which abuts the end of the plug 61 about the periphery of the latter and insures that in assembly the outer end of the conductor tube 59 is flush with circular plug shoulder 91 defining the step between the large and small diameter portions of the plug 61. Interposed between the shoulder 91 and the inside face 92 of the insulating and supporting disc 62 is a plastic insulating ring 93, which may also be formed of polytetrafluoroethylene or the like. Both the insulating ring 93 and a similar ring 94 disposed against outside face 95 of the disc 62 are of the same external diameter as the inner conductor tube 59 to obtain the desired electrical characteristics in the transmission line in view of the stepped construction and the change in dielectric from air to solid plastic insulation andback to air, involving as it does attendant changes in dielectric constant. To hold the insulating and supporting disc 62 and the insulating rings 93 and 94 in assembled relation on the reduced diameter portion of the plug 61, a circular metal cap 64 is held against the outer end of the plug as by a stud 65 that extends through a center bore hole in the cap and is threaded into an axially extending tapped hole in the plug 61. Desirably a shallow axial counterbore is formed in the cap 64 about the stud hole in the provision of an annular socket 96 that receives snugly an axially directed pilot extension on the outer end of the plug 61 to locate the parts in predetermined coaxial relation in assembly.

Suitable provision is made for attachment of the coupling line section to the end of a coaxial electrical transmission line. coupling line assembly projects axially beyond the supporting insulating disc 62 and such projecting or outer end is bored or otherwise relieved internally at 57 to receive one end of the outer tubular conductor 36 of the standard line coupling device. The tubular metal tube 36 is brazed or otherwise secured in the relieved end 57 of the tubular conductor portion 38 and the outer end of the conductor tube 36 carries or is secured in attaching ring 37 of a conventional union.

The inner conductor of the coupling line assembly includes a tubular conductor hail of brass or similar resilient metal having axial slots in its inner end portion. in the provision of resilient fingers 9% that slide over and yieldingly embracethe tapered periphery of the cap 64. in this respect the connection of the inner tubular conductor 98 to the cap 64 is similar to the connection of the tubular inner conductor 59 of the branch coupling line section to the cap '33. The fingers 89 of the conductor 5% and the fingers 99 of the conductor 98 are locatingly abutted axially against the insulating plastic washers '70 and 94, respectively. By reason of the frustoconical or tapered shape of the

caps

53 and 64 the electrical connections between the fingers and the caps are effected adjacent the axially directed circular radial faces of the caps which define the steps to the reduced diameter portions of the center conductor extending through the corresponding insulating partitions. Furthermore, the tapered or frustoconioal shape of the

caps

53 and 64 facilitates assembly, in that the ends of the

center conductor tubes

59 and 98 are easily located over the smaller ends of the caps and then slid axially into place with attendant slight radial distention of the

resilient fingers

89 and 99.

In the case of one of the conductor end caps, here the cap 64, provision is made for piloting into place the tubular conductor that is to be received over the cap. This supplemental pilot means takes the form of a metal tube 100 that is secured in endwise relation against the outer face of the cap and in coaxial relation thereto. The pilot tube 100 has an outer diameter preferably less than the internal diameter of the inner conductor tube 93, providing an annular clearance 10]. between the tubes so that the fingered end of the conductor tube Q8 is readily disposed over the pilot tube 100 during the initial stage of the assembly. The connections from the main transmission line to the present load device are thus made by bolting the end flange 37 of the coupling assembly outer conductor 36 to a similar mating union flange (not shown) on the transmission line outer conductor. The end of the inner conductor of the main line is simultaneously connected as by a suitable bullet connector (not shown) to the inner conductor tube 98.

As a precaution against overloading there is'provided a thermocouple, unit immersed in the liquid dielectric coolant 3 and connected to a conventional electrical safety cut out switch, not shown. The thermal unit is located Within a blind tube 75 which is fastened to a threaded bushing orplug '76 threaded into a ring 78 welded to the front housing wall 11. Lead wires 77 to the thermocouple extend to the safety device or, if desired to an indicating meter.

The unit is filled with the liquid dielectric coolant through a bushing '79 in the top wall of the housing. The bushing is internally threaded to receive a plug 81 and The outer tubular conductor 38 of the' the plug in turn is provided With a suitable safety vent screw.

The dielectric fluid within the housing is preferably one having a low dielectric constant, dielectric constants of the order of about three and below being satisfactory. It is preferable not to use dielectrics having constants above five because of the relatively large physical size of the outer conductor which would then be required in order to achieve the desired characteristic impedance equal to that of the transmission line. It is also desirable to use a fluid dielectric having substantially the same dielectric constant as the insulating partition 33 in order to avoid the reflective effect of a sudden change in dielectric characteristics. For an insulator 33 made of a compound known cormnercially as Teflon having a dielectric constant of the order of about 2.05, suitable liquid dielectrics are an eutectic mixture of diphenyl and diphenyl-oxide sold commercially as Dowtherm A and common mineral oil such as that sold commercially for medicinal purposes as Nujol having a dielectric constant of about 2.15. These liquids function effectively as coolants by reason of their relatively high specific heat capacity and low viscosity which facilitate convective flow through the housing and thereby insure rapid removal of heat from the inner conductor.

While a certain specific embodiment of the invention has been illustrated and described in detail, the same is intended as illustrative and not as limitative of the invention. The specific size and portions of the parts may be varied considerably without departing from the invention and it is accordingly int nded, in the appended claims to cover any such modifications coming within the true scope of the invention.

What we claim and desire to secure by Letters Patent of the United States is:

1. A junction for joining coaxial line sections each of which comprises an inner and a tubular outer conductor, said junction comprising an annular outer connector for extending between and electrically connecting the outer conductors of the line sections, an in connector for extending between and electrically connecting the inner conductors of the line sections, insulating means surrounding the inner connector and supporting it coaxially within the outer connector, and means having a surface inclined to the axis of the connectors providing a dovetail annular interlock between the insulating means and one of the connectors, said inclined surface engaging the insulating means over a relatively small fractional portion only of the radifl extent of the insulating means.

2. A junction for joining coaxial line sections each of which comprises an inner and a tubular outer conductor, said junction comprising an annular outer connector for extending between and electrically connecting the outer conductors of the line sections, an inner connector for extending between and electrically connecting the inner conductors of the line sections, an insulator surrounding the inner connector and supporting it coaxially within the outer connector, and means providing an interlock between the insulator and one of the connectors, the one connector including telescoping elements one of which is formed with a cylindrical locating surface and the other of which has a circumferential shoulder, the insulator having a cylindrical surface receivable in sliding relation against the locating cylindrical surface of the one element, the insulator having adjacent its said cylindrical surface a surface of revolution disposed in concentric relation to the other of the telescoping elements and of different diameter than the insulator cylindrical surface, the one element having an end face disposed in confronting relation to the shoulder on the other element, and means operative progressively to draw the elements axially together to clamp a portion of the insulator between the end face and the shoulder.

3. In an electrical high frequency device of the type comprising housing means formed with an opening and til containing liquid dielectric coolant and a coaxial line in the housing means and immersed in the liquid,

said line comprising a tubular outer conductor and, within the outer conductor and in coaxial relation to it, an inner conductor, the conductors being separated by a first annular dielectric space surrounding the inner conductor, means for connecting the conductors to a coaxial transmission line, said connecting means comprising an outer tube connector and, within and coaxial to said outer tube, an inner connector, the connectors being separated by a second annular dielectric space surrounding the inner connector, a centrally apertured insulating partition interposed between and separating the dielectric spaces, means extending through the partition aperture in sealing relation from inside to outside and connecting the inner conductor to the inner connector, an annular st ucture disposed across the opening of the housing means, embracing the partition and connecting the outer conductor to the tube connector, said structure comprising ring means rigidly attached to the housing means and to the outer conductor, the ring means having a radial inwardly directed shoulder constituting an inside abutment for the partition and, outside such shoulder, a circular surface concentric to the axis of the conductors and engaging the partition to center the latter in the ring means, the tube connector having a circumferentially extending radial surface disposed to bear against and constituting an outside abutment for the partition, the ring means being formed outside the centering surface with means engaging the tube connector and centering the latter in the ring means, holding means threadedly engaging one of said ring means and said tube connector and engaging the other thereof interlockingly and for relative rotational movement, said holding means being actuatable to apply opposite axial forces to the ring means and the tube connector to move the radial surface of such tube connector toward and against the partition progressively squeezing the latter between such radial surface and the shoulder of the ring means, and abutment means coacting between the ring means and the tube connector limiting said squeezing and providing axial alignment in the connection between the tube connector and th outer conductor, the tube connector being held in predetermined fixed location axially relative to the ring means and the outer conductor. 4. In an electrical high frequency device as claimed in claim 3,

the ring means having a counterbore outwardly of said circular partition centering surface, said counterbore providing a cylindrical surface engaging the tube connector for relative linear axial sliding movement and constituting said centering means engaging the tube connector. 5. In an electrical high frequency device as claimed in claim 3,

the holding means including a threaded ring threadedly engaging the ring means and, interposed between the threaded ring and the tube connector, split ring means, the split ring means and the tube connector having engaged radial shoulders constituting said interlocking engagement for transmitting said opposite forces. 6. In an electrical high frequency device as claimed in claim 3,

the ring means having first and second counterbores outwardly of said circular partition centering surface, said first counterbore providing a cylindrical surface constituting said centering means engaging 9 the tube connector, said second counterbore being formed with threads, and the holding means including a ring formed with external threads mating with said counterbore threads in the provision of said threaded engagement.

7. In an electrical high frequency device as claimed in claim 6,

the threaded ring having an internal diameter greater than the diameter of the first counterbore to permit assembly and removal of the threaded ring onto and from the tube connector over said outside abutment of the latter,

and said holding means including split ring means interposed between the externally threaded ring and the tube connector and adapted to transmit said opposite forces.

8. In an electrical high frequency device as claimed in claim 3,

the ring means including fastening ring means secured to the housing means and, within and axially movable relative to such fastening ring means, mounting ring means,

the outer conductor being fast to said mounting ring means in the provision of said rigid attachment of the outer conductor to the ring means,

said fastening ring means having a through opening larger than the profile of the coaxial line to permit bodily insertion and removal of the latter into and from the housing means through said opening in the fastening'ring means and while the outer conductor is fast to the mounting ring means.

9. In an electrical high frequency device as claimed in claim 3,

the opening of the housing means being non circular,

the ring means including fastening ring means secured to the housing means and extending through said non circular opening in mating relation,

and the ring means also including mounting ring means within and axially movable in assembly relative to such fastening ring means, the outer conductor being fast to said mounting ring means in the, provision of said rigid attachment of the outer conductor to the ring means.

10. In an electrical high frequency device as claimed in claim 3,

the ring means having a plurality of concentric internal stepped diameter portions,

a first of said portions being cylindricaland formed with said partition engaging surface,

a second of said portions also being cylindrical and constituting said connector engaging and centering means,

a third of said portions being threaded and threadedly engaged by said threaded means,

and said abutment means comprising radial stop means at the juncture of the first and second portions.

11. In an electrical high frequency device as claimed in claim 3,

the insulator having an annular radial surface portion engaged by one of the abutments and being formed with a circular groove concentric to the axis of the device and located at one of the margins of and limiting the radial extent of such radial surface.

12. A junction for joining coaxial electrical lines each of which comprises an inner and a tubular outer conductor,

said junction comprising an inner connector and, surrounding the inner connector in coaxial relation and separated therefrom by an annular dielectric space,

an annular outer connector,

the connectors being adapted to extend between and to mechanically and electrically connect the inner and outer conductors of one such line with the inner and outer conductors, respectively, of another such line,

an annular insulator disposed in the dielectric space in 1% surrounding relation to the inner connector and constituting a support for the latter within the outer connector,

said insulator comprising a body portion defined by surfaces of revolution about the longitudinal axis of the device, H the body portion having an annular gripping portion of uniform axial section,

one of the connectors including abutment means having confronting circular surfaces which are disposed on opposite sides of the gripping portion of the insulator and one of which is inclined with respect to said axis,

said one connector having relatively movable parts adapted to be actuated progressively to draw the confronting surfaces toward each other to engage and squeeze the gripping portion,

the radial extent of the engaged gripping portion constituting only a small fractional part of the entire radial extent of the insulator body, and the inclination of such one surface providing a dovetail mechanical interlock between the one connector and the gripping portion of the insulator.

13. A coaxial line junction as claimed in claim 12 in which the insulator includes an integral portion extending axially beyond said inclined one of the surfaces of the abutment means and also beyond the axial limits of the gripping portion.

14. A junction for joining coaxial electrical lines each of which comprises an inner and a tubular outer conductor,

said junction comprising an inner connector and, surrounding the inner connector in coaxial relation and separated therefrom by an annular dielectric space, an annular outer connector, the connectors being adapted to extend between and to mechanically and electrically connect the inner and outer conductors of one such line with the inner and outer conductors, respectively, of another such line, an annular insulator disposed in the dielectric space in surrounding relation to the inner connector and constituting a support for the latter Within the outer connector, c

said insulator comprising a body portion defined by surfaces of revolution about the longitudinal axis of the device,

the body portion having inner and outer peripheries each formed with an annular gripping portion of uniform axial section,

the inner and outer connectors each including abutment means having a pair of confronting circular surfaces which are disposed in confining relation on opposite sides of the inner and outer gripping portions, respectively,

one surface of each such pair being inclined with respect to said axis, the connectors each comprising parts relatively movable in assembly and adapted to be actuated progressively to draw the abutment surfaces toward each other in effecting a squeezing of the confined gripping portion of the insulator,

the radial extent of each of the squeezed gripping portions constituting only a small fractional part of the entire radial extent of the insulator body,

and the inclination of the abutment surfaces providing dovetail mechanical interlocks between the gripping portions of the insulator and the connectors respectively squeezing them.

15. In an electrical high frequency coaxial line device of the type'comprising a tubular outer conductor and, within the outer conductor and in coaxial relation to it, an inner conductor, the conductors being separated by a first annular dielectric space surrounding the inner conductor,

means for connecting the conductors to a coaxial transmission line, said connecting means comprising an outer tube connector and, within and coaxial to said outer tube, an inner connector, the connectors being separated by a second annular dielectric space surrounding the inner connector,

outer connecting means electrically connecting the outer conductor to the tube connector,

a centrally apertured insulating partition within and supported by the outer connecting means and interposed between and separating the dielectric spaces,

inner connecting means extending through the partition aperture and electrically connecting the inner coductor to the inner connector,

one of said inner and said outer connecting means comprising elements axially movable relative to one another and formed with confronting radial surfaces disposed on opposite sides of and adapted to engage the partition,

one of said elements being formed with a radial shoulder spaced axially from its radial surface,

a resilient sealing ring of readily deformable sealing material softer than the partition embracing said one element and located and held captive between the shoulder and the partition,

and means connecting and adapted to be actuated progressively to draw the elements together to squeeze the partition between said confronting surfaces independently of the sealing ring.

16. In an electrical high frequency coaxial line device of the type comprising a tubular outer conductor and, within the outer conductor and in coaxial relation to it, an inner conductor, the conductors being separated by a first annular dielectric space surrounding the inner conductor,

means for connecting'the conductors to a coaxial transmission line, said connecting means comprising an outer tube connector and, within and coaxial to said outer tube, an inner connector, the connectors being separated by a second annular dielectric space surrounding the inner connector,

one of said inner and said outer connecting means comprising a plug element on one side and a cap element on the other side or" the partition,

said elements having axially extending complemental guide surfaces engaged one on the other for axial sliding movement and having confronting radial surfaces the radial extent of which is only a small fractional portion of that of the partition, screw means connecting the elements and being actuatable to apply. opposite axial forces to the elements and progressively to squeeze the partition between the radial surfaces,

abutment means coasting between the elements limiting said squeezing,

the elements being held by said abutment means and said screw means in predetermined fixed axial rela- "i2 tionship, and one of said connecting means including an axially extending member having an end telescoping the cap and making yielding electrical contact therewith.

17. In an electrical high frequency coaxial line device of the type comprising a tubular outer conductor and, within the outer conductor and in coaxial relation to it, an inner conductor, the conductors being separated by a first annular dielectric space surrounding the inner conductor,

means for connecting the conductors to a coaxial transmission line, said connecting means comprising an outer tube connector and, within said coaxial to said outer tube, an inner connector, the connectors being separated by a second annular dielectric space surrounding the inner connector,

inner connecting means extending through the partition aperture and electrically connecting the inner conductor to the inner connector,

one of said inner and said outer connecting means comprising elements axially movable relative to one another and formed with confronting radial surfaces,

one of said elements having a cylindrical guide surface concentric to the axis of the device,

such one element having its radial surface disposed intermediate the cylindrical surface and the radial surface of the other element,

the partition having integral guide and grip portions, the guide portion engaging the guide surface of such one element and thereby centering the partition relative to such one element,

and the grip portion being disposed between the radial surfaces of the elements.

18. In a device as claimed in claim 17 the partition being formed with coaxial cylindrical peripheral surfaces of different diameters,

one such peripheral surface delineating the guide portion and being in engagement with the guide surface and the other such peripheral surface delineating the grip portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,449,073 Iohannesen Sept. 14, 1948 2,513,080 Burtt June 27, 1950 2,536,802 Fehr Jan. 2, 1951 2,552,707 Bird May 15, 1951 2,556,642 Bird June 12, 1951 2,663,753 Bird Dec. 22, 1953 2,822,418 Dinnick Feb. 4, 1958 2,882,509 Archer et al Apr. 14, 1959 2,904,619 Forney Sept. 15, 1959 FOREIGN PATENTS 839,587 Franc Ian. 4, 1939 840,649 France Jan. 23, 1939 879,562 Germany June 15, 1953 879,563 Germany June 15, 1953 v sc I

Claims

1. A JUNCTION FOR JOINING COAXIAL LINE SECTIONS EACH OF WHICH COMPRISES AN INNER AND A TUBULAR OUTER CONDUCTOR, SAID JUNCTION COMPRISING AN ANNULAR OUTER CONNECTOR FOR EXTENDING BETWEEN AND ELECTRICALLY CONNECTING THE OUTER CONDUCTORS OF THE LINE SECTIONS, AN INNER CONNECTOR FOR EXTENDING BETWEEN AND ELECTRICALLY CONNECTING THE INNER CONDUCTORS OF THE LINE SECTIONS, INSULATING MEANS SURROUNDING THE INNER CONNECTOR AND SUPPORTING IT COAXIALLY WITHIN THE OUTER CONNECTOR, AND MEANS HAVING A SURFACE INCLINED TO THE AXIS OF THE CONNECTORS PROVIDING A DOVETAIL ANNULAR INTERLOCK BETWEEN THE INSULATING MEANS AND ONE OF THE CONNECTORS, SAID INCLINED SURFACE ENGAGING THE INSULATING MEANS OVER A RELATIVELY SMALL FRACTIONAL PORTION ONLY OF THE RADIAL EXTENT OF THE INSULATING MEANS.