US2919300A - Conductor insulator combinations or the like - Google Patents

Description

Dec. 29, 1959 CARLSQN 2,919,300

CONDUCTOR INSULATOR COMBINATIONS OR THE LIKE Filed Jan. 29, 1954 RICHARD G. CARLSON INVENTOR.

a ms ATTORNEY United States Patent CONDUCTOR lNSULATOR CONIBINATIONS OR THE LIKE Richard G. Carlson, San Gabriel, Calif., assignor to Hoffman Electronics Corporatiou, a corporation of California Application January 29, 1954, Serial No. 407,125

1 Claim. (Cl. 174-153) This invention relates to improvements in electrical terminals and conductors and more specifically to a simplified andimproved conductor-insulator combination.

In the past a number of devices have been developed for conducting electrical currents through a barrier of conductive material, such as a chassis pan, without actually permitting the electrical currents to pass into the conductive chassis pan. Some of these devices have utilized a metal-jacketed ceramic. The outer metal jacket is soldered in place in a hole in the chassis pan and the feed-thru conductor is supported along the axis of the outer jacket but separated therefrom by a ceramic insulator. Such devices are subject to destruction during the soldering operation as a result of the dilference in the heat expansion coeflicients of the ceramic and the metal parts of the feed-thru. Other devices have utilized an insulator of Teflon or the like through the axis of which a conductor is passed, the outer diameter of the plastic cylinder being accurately set at a value extremely close to the actual diameter of the hole in the chassis through which the feed-thru is to pass. The hole in the chassis must also have accurate dimensions and be countersunk. The types of feed-thru devices just described are expensive to install.

Therefore, it is an object of this invention to provide a simple but effective insulated conductor-insulator combination.

It is a further object of this invention to provide an insulated feed-thru conductor, which may be installed in apertures which are not easily accessible.

It is a still further object of this invention to provide an insulated feed-thru conductor which may be installed with ease and at minimum expense.

It is a yet further object of this invention to provide an insulated feed-thru conductor which, when in operating position, will provide an air-tight seal with the chassis or other means supporting it.

According to this invention there is provided a plastic insert of Teflon or other pliable plastic which is flanged at one end and which has a generally cylindrical shape and has a hole of predetermined dimensions passing along its, axis for its entire length. The metal portion of the feed-thru is constructed with sections of increasing diameter from one end of it to the other and tapered shoulders connecting the successively larger sections. The section of the smallest diameter, or stem, has the greatest length and is of a diameter substantially equal to the diameter of the aperture along the axis of the insulating insert.

To install this insulated feed-thru, a hole is cut in the chassis, the diameter of that hole being substantially that of the outer diameter of the smaller section of the insulator and that insulator is inserted in the hole with the flange on the outward side of the chassis. The long thin section of the conductor is inserted in the aperture along the axis of the insulator either before or after the insulator is placed in position in the chassis, and, with the narrow portion protruding from the outer face of the chassis. A simple tool has been devised to pull this nar- 2,919,300 Patented Dec. 29, 1959 row portion outward while holding the insulator flange against the chassis pan, with the result that the conductor sections of successively larger diameter are pulled into position within the Teflon or other resilient plastic, causing that plastic to expand forming a shoulder on the remote face of the chassis and at the same time forcing the outer walls of the plastic into very tight contact with the edge of the opening in the chassis. The result is a seal which is strong mechanically and which is resistant to the passage of air even under pressurized conditions. An annular indentation may be provided in the section of the conductor having the largest diameter to assure positive retention of the conductor in the plastic.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claim. The present invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings in which:

Figure 1 is an elevational view, partially sectional, of one form of the invention before installation;

Figure 2 is an elevational view, partially sectional, which shows the feed-thru of Figure 1 after installation;

Figure 3 is an elevational view, partially sectional, of a second embodiment of this invention; and,

Figure 4 is an elevational view, partially in section, showing the embodiment of Figure 3 after installation.

In Figure l, insulator 10 comprises flange portion 11 and insert portion 12. Aperture 13 is drilled or otherwise formed along the axis of insulator 10. Conductor 14 comprises stem 15 of a first diameter substantially equal to the diameter of aperture 13, intermediate section 16 of enlarged diameter, joined by a tapered portion 17 with the first portion 15 and by a second tapered portion 18 to terminal portion 19 of still larger diameter. A peripheral groove 20 may be provided for easy attachment of wires or other conductors. Conductor 14 may be made from inexpensive material in a simple screw machine operation and may then be plated so that soldering to it is simplified and to increase its corrosion resistance.

To achieve the installed position shown in Figure 2, an aperture having the same contour and substantially the same diameter as insert portion 12 of insulator 10 is cut in a chassis or other base 21. Conductor 14 may be put in an initial relationship to insulator 10 by inserting stem portion 15 in aperture 13. This initial assembly may then be inserted in entirety in aperture 22 of base 21, with flange portion 11 of insulator 10 and stem portion 15 extending from the outer face of base 21. By maintaining flange 10 in contact with the face of chassis or base 21 while at the same time pulling stem portion 15 outwardly from that face, intermediate portion 16 will be pulled into position in aperture 13 and ultimately terminal portion 19 will be pulled partially into the expanded aperture 13 in the insert portion 12 of insulator 10. When this condition has been reached, insert portion 12 will fit very snugly within aperture 22 and a pressurized seal will be obtained between terminal portion 19, insert portion 12 and chassis or base 20. Insulator 10 must,

-of course, be of a pliable material and a commercially In Figure 3 an additional annular groove 300 is provided in terminal portion 19 and insert portion 12 of insulator 10 is lengthened to compensate for the increase in length of terminal portion 19 occasioned by the inclusion of groove 300.

As can be seen from Figure 4, the inner wall of insert portion 12 conforms to the contour of annular groove 300 when conductor 14 reaches its installed position. A greater degree of retention of conductor 14 in insulator 10 is thus effected.

It should be noted that with little or no modification the combination of conductor 14 and insulator 10 may serve a standoff insulator function.

Thus, it may be seen that there has been provided a conductor-insulator combination which may serve a feedthru or standoif insulator function and which requires no close manufacturing tolerances, provides possibilities of hermetic sealing and is adapted to be applied to blind holes in a simple operation without soldering or complex mechanical operations.

While particular embodiments of the present invention have been shown and described, it is apparent that various changes and modifications may be made, and it is therefore contemplated in the appended claim to cover all such changes and modifications as fall within the true spirit and scope of this invention.

I claim:

A conductor-insulator and apertured chassis combination of the chassis-aperture feed-through type adapted for blind installation from one side of a chassis by a pulling operation, including a cylindrical conductor unit having an elongated stern portion, an intermediate body portion of larger diameter than said stem portion, a terminal portion of larger diameter than said intermediate body portion and having an annular groove, and sections tapering toward said stem portion connecting said portions;

and a cylindrical radially-expandible plastic insulator unit having an axial bore sized to receive said elongated stem and whose outer surface is defined by an insert portion whose diameter exceeds that of the terminal portion of said conductor unit, and an adjacent chassis-engaging flange portion of still greater diameter; said elongated stem portion of the conductor unit being substantially longer than the total axial length of said insulator unit to enable the remainder of said conductor unit to be pulled bodily into embedded position within said insulator unit from the flange end thereof, thereby to produce a twostage expansion of the insert portion into sealing engagement with the wall of the panel aperture as well as into expanded upset engagement with the face of the panel opposite to said flange portion of the insulator unit; said conductor unit being inserted in said insulator unit and said conductor-insulator combination being inserted in the aperture of said chassis with said panel-engaging flange contacting one side of said chassis about said aperture and said insert portion deformed by said terminal portion of said conductor unit and engaging the other side of said chassis and with said groove lying substantially in the plane of said apertured chassis.

References Cited in the file of this patent UNITED STATES PATENTS 2,433,911 Johnston Ian. 6, 1948 2,436,644 Halstead Feb. 24, 1948 2,592,130 Erb et al Apr. 8, 1952 2,678,346 Garraway May 11, 1954 2,774,812 Clark Dec. 18, 1956 2,806,080 Corey Sept. 10, 1957 FOREIGN PATENTS 641,917 Great Britain Aug. 23, 1950

Images