US3154362A - Transmission-line connector - Google Patents

Description

1964 l. s. BLONDER ETAL 3,

TRANSMISSIONLINE CONNECTOR Filed Aug. 10, 1962 INVENTORS ISAAC S. BLONDER WALTER EDWARD SAMPSON ATTORNEYS United States Patent 3,154,362 TRANSMISSIGN-LENE CONNECTOR Isaac S. Blonder, West Orange, and Walter Edward Sampson, Westdeld, N.J., assignors to Blonder Tongue Electronics, Newark, N.J., a corporation of New Eersey Filed Aug. 10, 1962, Ser. No. 216,188 Claims. (Cl. 339-97) The present invention relates to transmission-line connectors and, more particularly, to connectors used with coaxial transmission lines and the like, such as those employed in audio-frequency and radio-frequency systems.

Several types of connectors have been evolved for attachment to the ends of transmission lines without requiring solder connections and their attendant inconvenience and other disadvantages. One successful connector of this character, for example, is disclosed in United States Letters Patent No. 3,001,169, granted on September 19, 1961, to I. S. Blonder, one of the present applicants. Such connectors, however, generally require locking collars and other moving parts and/or heavy metal construction, including, in some instances, machined parts or the like, that, in some applications, where very low cost and very rapid assembly are required, are not desirable.

An object of the present invention, accordingly, is to provide a new and improved solderless connector for a coaxial transmission line or the like that is particularly adapted for very low cost and facile attachment and that may be fabricated inexpensively from thin sheel metal.

A further object is to provide a novel connector of more general utility, as well.

Other objects will become evident in the description to follow and will be particularly pointed out in the appended claims.

In summary, the objects of the present invention are attained with the aid of a hollow male plug for receiving the inner conductor of the line, the plug being partially peripherally closed near its free end to provide a reduced diameter terminal portion, and a rubber-like insert extending longitudinally Within the hollow of the plug and through and beyond the reduced-diameter terminal portion and free end thereof, said insert being of cross-dimension slightly less than the inner cross-dimension of the plug in order to prevent compression thereof within the hollow of the plug, but of slightly greater cross-dimension than the reduced-diameter terminal portion in order to compress the insert at that terminal portion.

The invention will now be discussed in connection with the accompanying drawing in which,

FIG. 1 is a perspective of a connector embodying the invention in preferred form;

FIG. 2 is a section view taken upon the line 22 of FIG. 1, looking in the direction of the arrows, but upon a greatly enlarged scale; and

FIG. 3 is a longitudinal section of the connector of FIG. 1, also upon an enlarged scale, showing a coaxial transmission line secured thereto.

Referring to the drawing, the connector is provided with a substantially circular-cylindrical male conductive plug 1 for receiving the inner conductor 7, FIG. 3, of a coaxial transmision line, 19, the outer conductor 3 of which is insulated from the inner conductor 7 at 3' and is itself covered with insulation at 3". The plug 1 is partially peripherally closed near its free end, as at 1', to provide a reduced diameter terminal portion for a purpose later explained.

A resilient insert 6, as of, for example, rubber, neoprene and the like, is disposed to extend longitudinally within the hollow of the plug 1 and through and beyond the reduced-diameter terminal portion 1 and free end thereof. As is later evident, the length of the insert 6 is preferably "ice greater than that of the plug 1. The insert 6 is also preferably of substantially square cross-section and of diagonal cross-dimension just slightly larger than the inner crossdimension of the plug, as more particularly shown in FIG. 2. The side-dimensions of the insert are accordingly less than the inner diameter of the plug, in order to prevent substantial compression of the insert within the hollow of the plug when an inner conductor 7, of diameter substantially of the relative dimension shown in FIG. 3, is inserted into the plug in the space 12, FIG. 2, between a side of the insert 6 and the adjacent inner wall portion of the plug 1. The diameter of the inner conductor 7 is thus not substantially greater than the maximum crossdimension of the space 12 in the preferred construction. Such a goemetry and actual dimensioning insures that the frictional force exerted upon the corners of the substan- 'ally square resilient insert 6 by the inner wall of the plug 1, holds the insert 6 against longitudinal movement as the inner conductor 7 is inserted into the plug 1. In the absence of such relationship, the resilient insert 6 has been found to be forced longitudinally along the plug 1 and out of the reduced-diameter terminal position 1' as the inner conductor 7 is so inserted.

The insert 6, however, is made of greater cross-dimension than the reduced-diameter terminal portion 1 of the plug 1 in order to compress the resilient insert 6 at that terminal portion and to permit an expansion therebeyond, as at 6', FIG. 3. Though the inner conductor 7 is forced into contact with the inner surface of the plug 1 substantially throughout the length thereof, it has been found that an invariably reliable electrical connection is established and maintained at the region 7' of forced engagement against the reduced-diameter terminal front wall 1.

The plug 1, moreover, is coaxially mounted with respect to an outer cylindrical conductive shell 2, being carried by an apertured insulating disc 4, crimped as at 2' to an end of the shell 2.

The conductive shell 2 itself is longitudinally slotted to provide a plurality of resilient fingers 18 extending rearwardly over a substantial portion of the length thereof, between longer fingers or cylindrical wall strips 19. The fingers or strips 19, are provided with inwardly extending prongs 19 for piercing the outer coaxial line insulation 3" of the line 11 inserted there-within. Electrical connection is thus established with the outer conductor 3 of the line it; as the prongs 19' are forced radially inward by a clamping ring 21, fitted over the resilient inwardly bent terminal portions 19" at the free ends of the strips 19.

As before stated, this construction enables ready and inexpensive fabrication from sheet metal, and obviates the means for heavy parts, locking collars and similar devices, while providing a strong and reliable solderless connection to the line.

Modifications will occur to those skilled in the art, and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. Apparatus for providing a facile connection to a transmission line, comprising a tubular conductive plug having an opening at its forward end and an opening at its rearward end with a passage extending between said openings, said plug having an interior peripheral constriction adjacent to the opening at its forward end to provide a terminal portion of reduced cross-dimension, a resilient insert extending longitudinally within said passage and through said terminal portion, said insert having a crossdimension less than the corresponding cross-dimension of said passage to provide a space between said insert and said plug, said insert being free of substantial compression in said passage, said cross-dimension of said insert being a greater than the corresponding cross-dimension of said terminal portion and said insert being substantially resiliently compressed by said terminal portion, a transmission line conductor being introduced into said rearward end of said plug and passing longitudinally through said space between said insert and said plug, and between said terminal portion and the resiliently compressed insert thereat, said conductor being forced into reliable electrical connection with said terminal portion by said insert.

2. The invention of claim 1, said insert being substantially rectangular in cross-section, having its corners engaging the interior surface of said plug, and having its sides spaced from said surface.

3. The invention of claim 2, said plug being a metal sleeve of circular cross-section, said insert being of rubberlike material and having a square cross-section with diagonal dimensions slightly greater than the inner diameter of said sleeve.

4. A connector for a coaxial transmission line comprising a tubular conductive plug having an opening at its forward end and an opening at its rearward end with a passage extending between said openings, said plug having an interior peripheral constriction adjacent to the opening at its forward end to provide a terminal portion of reduced cross-dimension, a resilient insert extending longitudinally Within said passage and through said terminal portion, said insert having a cross-dimension less than the corresponding cross-dimension of said passage to provide a space between said insert and said plug, said insert being free of substantial compression'in said passage, said cross-dimension of said insert being greater than the corresponding cross-dimension of said terminal portion and said insert being substantially resiliently compressed by said terminal portion, a conductive shell having a forward end secured to the rearward end of said plug by an insulating washer, said shell having a plurality of rearwardly extending resilient fingers at least one of which is provided with inwardly extending prong means, said shell being dimensioned to receive the end of a coaxial line'and having means for clamping the fingers to cause said prong means to engage the outer conductor of the line, said plug being dimensioned to receive the inner conductor of the line through the opening at the rearward end of the plug, through the space between said insert and said plug, and between said terminal portion and the resiliently compressed insert thereat, to cause said inner conductor to be forced into reliable electrical connection with said terminal portion by said insert.

5. The connector of claim 4, the length of said insert being greater than the length of said plug.

References Cited in the file of this patent UNITED STATES PATENTS 2,630,468 Felts et al Mar. 3, 1953 2,677,118 Stone Apr. 27, 1954 2,807,791 Wallo Sept. 24, 1957 2,820,209 Whitted Jan. 14, 1958 2,839,595 Felts et al June 17, 1958 3,001,169 Blonder Sept. 19,1961 3,024,437 Van Deusen Mar. 6, 1962 3,059,208 Concelman H Oct. 16, 1962 FOREIGN PATENTS 531,947 Great Britain Jan. 14, 1941

Claims (1)

1. APPARATUS FOR PROVIDING A FACILE CONNECTION TO A TRANSMISSION LINE, COMPRISING A TUBULAR CONDUCTIVE PLUG HAVING AN OPENING AT ITS FORWARD END AND AN OPENING AT ITS REARWARD END WITH A PASSAGE EXTENDING BETWEEN SAID OPENINGS, SAID PLUG HAVING AN INTERIOR PERIPHERAL CONSTRICTION ADJACENT TO THE OPENING AT ITS FORWARD END TO PROVIDE A TERMINAL PORTION OF REDUCED CROSS-DIMENSION, A RESILIENT INSERT EXTENDING LONGITUDINALLY WITHIN SAID PASSAGE AND THROUGH SAID TERMINAL PORTION, SAID INSERT HAVING A CROSSDIMENSION LESS THAN THE CORRESPONDING CROSS-DIMENSION OF SAID PASSAGE TO PROVIDE A SPACE BETWEEN SAID INSERT AND SAID PLUG, SAID INSERT BEING FREE OF SUBSTANTIAL COMPRESSION

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