US3528052A - Right angle connectors - Google Patents

Description

p 8, 1970 A. R. BRISHKA 3,528,052

ANGLE 0 N C CR5 Filed May 15, 1968 RIGHT C N E T 2 Sheets-Sheet. 1

42 27 FIG. 1 F 48 P3 64 ALEXANDER R. BRISKA 62 a INVENTOR.

JOHN P CHANDLER HIS ATTORNEY.

United States Patent 3,528,052 RIGHT ANGLE CONNECTORS Alexander R. Brishka, 14 Sophia St., Mamaroneck, N.Y. 10543 Continuation-impart of application Ser. No. 659,729,

Aug. 10, 1967. This application May 13, 1968,

Ser. No. 728,648

Int. Cl. H01r 17/18 US. Cl. 339177 4 Claims ABSTRACT OF THE DISCLOSURE A right angle coupling for high frequency concentric lines includes a conductive housing having coupling means at either end. An air cavity adjoining a bend in the insulation on the central conductor corrects for a bad impedance match and reduces wave reflection.

This application is a continuation-in-part of my copending application Ser. No. 659,729, filed Aug. 10, 1967, and now Pat. No. 3,432,798.

This invention relates to angular electrical connectors and more particularly to right angle coupling units used for high frequency signals.

An object of the present invention is to provide an angular connector for concentric lines having improved electrical characteristics. Another object is to provide an improved right angle connector which eliminates, as far as possible, impedance discontinunities and thereby excludes wave reflections at the connector.

The usual practice in forming angular or elbow connectors has been to use a two piece contact and insulator design to form the right angle and then solder the two straight contacts together. The cavity surrounding the joint is then filled with insulating material, or the cavity may be left unfilled with air acting as the dielectric. This device gives poor electrical performance due primarily to the varying relationships between the outer diameter of the inner conductor and the inner diameter of the outer conductor.

The present invention provides a right angle connector with the usual cylindrical insulation provided for the concentric line. At the portion of the line where both the inner conductor and its cylindrical insulation covering are bent at an angle, the outer covering is always stretched to a considerable degree and for this reason its thickness is reduced, thereby changing the impedance of the line, and introducing wave reflections. An attempt has been made to solve this difliculty by packing finely divided conductive material around the bend and thereby simulate a continuous outer conductive coating. This means, while eliminating part of the trouble, does not completely solve the problem because the conductive material is then closer to the inner conductor due to the fact that the insulation has been diminished at this point. One method of eliminating this discontinuity is to omit the finely divided material but provide an enclosing conductive structure filled with air as the dielectric insulating covering. This type of structure generally overcompensates for the change in impedance and, to produce a nonreflective coupling, a portion of the conductive plating and some of the insulation at the bend is removed by means of a file or other cutting tool. Still another compensating means is to provide a similar enclosing structure and insert a conductive filler next to the reduced insulation. The portion of this conductive filter and/ or plating which is adjacent to the bend must be hollowed out and/ or removed at the apex of the bend so that a variable air space is supplied to that portion of the line.

3,528,052 Patented Sept. 8, 1970 ice In the drawings:

FIG. 1 is a central longitudinal cross section taken through a right angle connector embodying one form of the invention;

FIG. 2 is a cross sectional view of the connector shown in FIG. 1 and is taken along line 22 of that figure;

FIG. 3 is a cross sectional view of the connector shown in FIG. 1 and is taken along line 3-3 of that figure;

FIG. 4 is a cross sectional view of a portion of the connector shown in FIG. 1. This view shows a conductive insert having a cut-out portion which produces a variable air gap;

FIG. 5 is a graph showing the approximate directions of the lines of force in the electric field when a portion of the plating has been removed from the insulator and there is no adjoining conductor.

The right angle connector shown in FIG. 1 employs a single contact conductor of substantially the same diameter as the central conductor 11 of a coaxial cable 12, the contact being enclosed in an insulating sleeve 14. The insulating sleeve 14, enclosed in conductive portions 27 and 69 of the coupling components, forms an adequate outer conductor for a wide range of high frequencies without serious power loss. However, when the transmitted power frequency is above 10 Hz., the losses are excessive and it has been found necessary to surround the insulating sleeve in the region of the bend with conductive particles or plating or a combination of both in order to provide a continuous conductive path between portions 27 and 69. The plating may be either silver or gold or some other metal.

One end of the contact 10 may have a reduced or rounded terminal section 18 which is received in force fit relationship in a female Contact having a solid central section 19, a slotted bore 20 to receive the contact and a bore 22 at its other end to receive the central conductor 11. Section 19 is surrounded by a cylindrical insulator 14A. The wall of bore 22 may have an opening for outgasing purposes as well as to receive a drop of solder shown at 24. The other end section of the contact is rounded and is of reduced diameter near its end 26 in order to be received in a female contact (not shown) for connection with another coaxial cable.

A tubular body 27 receives one end of the insulated right angular contact and, at one end, it has a bore 28 for receiving one end of the insulated covering 14. The inner end of bore 28 is chamfered at the end of the bore to facilitate the entry of the insulated contact. The section of the tubular body 27 adjacent to the end of the central contact 10 is enlarged slightly as indicated at 30 and an additional enlarged bore indicated at 31 is provided for an insulating washer 33 positioned adjoining to a metal bushing 32. A similar metal bushing 34 is positioned on the other side of washer 33 and these three units are clamped into place by a short length of pipe having threads which mesh with internal threads on body 27 and a wrench receiving extension 42 for screwing into place. The washer 34 is formed with slotted wedge-like projections 36 which fit against a tapered section 38 of the internal surface of the pipe 42 and thereby facilitates a close fitting between the body 27 and the external surface of conduit 12. The opposite end of this body member 27 has a reduced threaded section 46 which receives a sleeve 48 internally threaded to receive section 46. Sleeve 48 is also internally threaded at its other end 52 to receive a closure plug 54. The lower portion of sleeve 48, when viewed as in the drawing, has a threaded hole 56 to receive a reduced threaded terminal 58 of a tubular body whose axis is at right angles to the major axis of body member 27 and has an upper flange which is screwed tight against its adjoining portion of member 27.

A coupling nut 63 is formed with a wrench receiving surface 62 and is connected to body 58 by a split locking ring 64 positioned in aligned annular slots formed in members 58 and 62. Body 58 has a bore 69 of such size as to receive the insulation 14 of the contact in snug fit. A sealing gasket 66 is positioned in a recess 70 near the outer end of body 58, thus providing a seal between the body 58 and its coupling nut 63. An internal thread 71 is provided on the inside portion of the nut 63 for connection to another coupling unit.

When bending the conductive portion 10 at right angles the outer insulation, which may be Teflon, is elongated and for this reason its thickness is reduced. In FIG. 1, the normal extent of the insulation is shown by dotted line 73. Since there is always a reduction in thickness, a compensation means must be pr vided to maintain substantially constant impedance along all portions of the line. The conductive plating 15 is removed from this part of the insulation and the hollow portion 74 within the sleeve 48 is used to provide this compensation because the distance between the center conductor and the surfaces of cavity 74 is greater than the distance between the center conductor and the plating adjacent to the exposed Teflon insulating material. The sleeve 48 and the plug 54 are both conductive and the air portion inside cavity 74 acts as additional insulation which is added to that portion of the Teflon insulating 14 adjoining it. The electrical field lines existing in the region of the removed plating will terminate on the outer conducting surface of the plating in the immediate vicinity of the unplated portion of the insulating material as shown in FIG.5. The increase in the length of the electric field lines results in an increased impedance section, thus providing a means of compensation for the impedance discontinuity and reduction of wave reflection.

Referring now to FIG. 4, the structure is similar to that shown in FIG. 1 except that a conductive insert 76 has been added to the cavity 74 formed by the inside surface of sleeve 48. The insert 76 is formed with a concave surface 77 which is generally in the form of a portion of a sphere and this portion, as shown in FIG. 4 fits over the insulation covering 14 where it has been reduced in thicknes. As before, the air space between the Teflon covering 14 and the conductive boundary 77 of the air space compensates for the change in impedance caused by stretching the insulation. A fiat spring 78 may be added to the insert 75 in order that the closure plug 54 may retain the insert in conductive contact with the cylindrical body 27 at all times. In this embodiment, as illustrated in FIG. 4, compensation is achieved in a different manner, viz., the electric field lines in the region of the bend terminate on the concave surface of the insert.

While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that many modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An angularconnector for joining two sections of a concentric conductor comprising a single central conductor with end contact portions and formed with an angular bend covered with solid insulation between its contact portions, a main tubular body having a bore to receive one end of the insulation and having a first terminal portion to receive another conductor, an inner conductive extension of said main body, axially aligned therewith, and enclosing the bend portion of the central conductor and its insulation covering, conductive closure means at the outer end of said extension, said extension and said closure means defining an air space adjoining the insulation covering on the convex bend portion, a conductive insert positioned in said space and formed with a concave surface adjacent to the convex surface of the insulation at its bent portion for providing a restricted air space which compensates for the change in impedance due to the reduced thickness of solid insulation at the bend, said extensionhaving a side wall opening and a conductive tubular extension secured in the opening at an angle to the main tubular body for supporting the other end of the central conductor and its insulation and for forming a second terminal portion.

2. A connector as claimed in claim 1 wherein said concave surface in the insert is formed with the shape of an ellipse.

3. A connector as claimed in claim 1 wherein said insert includes edge portions bordering the concave space which are substantially adjoining the insulation on the central conductor.

4. A connector as claimed in claim 1 wherein said insert is provided with a resilient means for holding at least one edge portion in conductive contact with the main tubular body.

References Cited UNITED STATES PATENTS 2,754,487 7/1956 Carr et al. 339--102 2,755,331 7/1956 Melcher 174-87 3,432,798 3/ 1969 Brishka.

RICHARD E. MOORE, Primary Examiner I. H. McGLYNN, Assistant Examiner

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