US 3533046 A
Description (OCR text may contain errors)
O 1970 H. W.BANNING 3,
PRECISION MINIATURE SEXLESS COAXIAL CONNECTOR Filed Dec. 16, 1968 FlG.2
INVENTOR. HARMON W. BANNING ATTORNEYS United States Patent US. Cl. 339-48 6 Claims ABSTRACT OF THE DISCLOSURE A miniature sexless coaxial connector is characterized by an inner conductor sliding spring mechanism to establish coupling between like connectors while introducing negligible mismatch.
BACKGROUND OF THE INVENTION The present invention relates to precision sexless miniature connectors and more particularly concerns a novel miniature coaxial connector suitable for use with 3.5 millimeter lines while introducing negligible mismatch or unwanted resonances.
The use of a Spring-l0aded inner conductor for a precision coaxial sexless connector is not in and of itself new. There exists such a connector for use in 7 mm. coaxial lines. However, practical difliculties are encountered when merely scaling down this connector to the 3.5 mm. size.
Accordingly, it is an important object of this invention to provide a precision sexless coaxial connector suitable for use with 3.5 mm. lines that is reliable, relatively easy and inexpensive to fabricate and exhibits excellent electrical properties over a wide bandwidth.
It is a further object of the invention to achieve the preceding object while introducing relatively little mismatch over a wide range of frequencies.
SUMMARY OF THE INVENTION According to the invention, there are means defining an outer conductor and an inner conductor assembly having an inside portion maintained in fixed relationship with respect to the other conductor means and an outside portion that is axially slideable and radially fixed relative to the axis of the connector. The inner conductor assembly includes spring means in a region around an outside stud that is inside the circularly cylindrical cavity at the inside end of the inner conductor outside portion. The bottom of this cavity is defined by an annular shoulder or base formed with an opening of diameter slightly larger than the diameter of the stud, but slightly less than the diameter of a screwhead. The stud is internally tapped to accommodate a screw having that screwhead so that the screwhead coacts with the base to limit the outward movement of the outside portion as the surrounding spring urges the inside and outside portions apart to insure good contact with the inner conductor of a like sexless coaxial connector. The inside portion also includes a beveled shoulder upon which the inside surface of the outside portion rides.
Numerous other objects, advantages and features of the invention Will become apparent from the following specification when read in connection with the accompanying drawing in which:
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a longitudinal sectional view through a connector according to the invention; and
FIG. 2 is a sectional view through the inner conductor assembly according to the invention.
3,533,046 Patented Oct. 6, 1970 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS With reference now to the drawing and more particularly FIG. 1 thereof, there isshown a sectional view through a connector according to the invention. The outer conductor assembly includes a main conducting portion 11 that carries an annular-dielectric bead 12 in the inside end of the connector surrounding an inner conductor inside end portion 13 of slightly smaller diameter than the main length of the inner conductor so that the characteristic impedance of the connector along the entire length is substantially constant. The inner conductor assembly includes a fixed inside portion 14 that is supported by three radial pins 15 equiangularly disposed about the connector axis between compensating pairs of holes, such as 16. The outer conductor assembly also carries a crenellated alignment ring 17 at its outside end that is held in place by the internally and externally threaded collar 21. An internally threaded coupling nut 22 completes the outer conductor assembly.
The inner conductor assembly includes a moveable outside portion 23 that is slideable along the axis of the connector but maintained in precise concentric relationship with respect to the outer conductor.
Referring to FIG. 2 there is shown a detailed magnified longitudinal sectional view of the inner conductor assembly near the outside end of the connector helpful in understanding the invention. The unitary circularly cylindrically symmetrical conducting part 24 is formed with an outside stud 25 that fits snugly within the hollow end of assembly 14 in fixed relationship thereto. Its outside end is formed with a stud 26 having a threaded opening 27 for accommodating a screw 31. A hollow conducting cylinder 32, urged away from conducting member 24 by spring 30 and limited in axial end travel by the head of screw 31, completes the inner conductor assembly. A feature of the invention resides in forming the shoulder 33 of member 24 upon which the inside wall of member 32 slides slightly bevelled as shown to help reduce electrical mismatch. Member 32 is formed with a central opening 34 of diameter slightly greater than that of outside stud 26 and less than the diameter of the head of screw 31 and the diameter of spring 30. Actual contact with the inner conductor of a like mating connector occurs along the annular outer surface 35 as the spring 30 urges member 32 against a like member to insure good reliable contact.
Referring again to FIG. 1, actual connection occurs by sliding back the coupling nut 22 on one connector and screwing the coupling nut of the other connector around the outside threads of member 21 as the crenelated alignment rings and the two connectors interleave and engage one another. The specific crenelated ring and coupling nut assembly is known in the art and not a part of this invention.
The invention is relatively easy and inexpensive to fabricate. The member 24 may be accurately formed. Assembly is relatively easy to accomplish by putting spring 30 over stud 26, sliding member 32 over member 24, and screwing screw 31 into threaded opening 27.
There has been described a novel connector assembly that represents a practical high performance 3.5 mm. sexless coaxial connector. It is evident that those skilled in the art may now make numerous uses and modifications of and departures from the specific embodiment described herein without departing from the inventive concepts. Consequently, the invention is to be construed as embracing each and every novel feature and novel combination of features present in or posessed by the apparatus and techniques herein disclosed and limited solely by the spirit and scope of the appended claims.
The bevelling of shoulder 33 performs a dual function. It provides a means for effecting good contact with the inside wall of hollow conducting cylinder 32 over a range of relative axial displacement. It also increases slightly the effective diameter of the outer surface of cylinder 32 (this cylinder having four longitudinal slots in space quadrature to permit some expansion) to introduce an eifective capacity that compensates for the inductive effect of the gap immediately adjacent to the cylinder open end and of the slots.
The slight difference between the diameter of opening 34 and stud 26 allows a slight axial misalignment of inner conductors of mating connectors to insure a good connection with good electrical characteristics despite slight mechanical imperfections.
What is claimed is:
1. A precision miniature coaxial sexless connector comprising:
means defining an outer conducting surface having an inside axis,
an inner conductor assembly inside said means defining an outer conductor,
said inner conductor assembly including an outside stud of first diameter contiguous with a shoulder of second diameter" greater than said first diameter and formed with an internally threaded opening for re ceiving a screw,
a hollow conducting element open at one end having its inside wall axially slideable along said shoulder and having a base at the other end formed with an opening of third diameter slightly larger than said first diameter,
spring means in the region between said shoulder and said base urging said shoulder and said base apart,
4 v and a screw in said threaded opening having a head of fourth diameter slightly greater than said'thirddiameter for limiting the axial displacement of said base.
2. A precision miniature coaxial sexless connector in accordance with claim 1 wherein said shoulder is slightly bevelled.
3. A precision miniature coaxial sexless connector in accordance with claim 1 wherein said spring means is a helical spring surrounding said outside stud and of fifth diameter greater than said third diameter and less than said second diameter.
4. A precision miniature coaxial sexless connector in accordance with claim 2 wherein said spring means is a helical spring surrounding said outside stud and of fifth diameter greater than said third diameter and less than said second diameter.
5. A precision miniature coaxial sexless connector in accordance with claim 1 wherein said outside stud and said shoulder comprise a unitary structure.
6. A precision miniature coaxial sexless connector in accordance with claim 5 wherein said unitary structure comprise an inside stud at its inside end.
References Cited UNITED STATES PATENTS 2,117,029 5/1938 Larsson 173332 2,690,542 9/1954 Pearce 33948 RICHARD E. MOORE, Primary Examiner L. I. STAAB, Assistant Examiner US. Cl. X.R.