US3778752A

US3778752A - Connector contact including an isolation resistor

Info

Publication number: US3778752A
Application number: US00202320A
Authority: US
Inventors: L Noyes
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1971-11-26
Filing date: 1971-11-26
Publication date: 1973-12-11
Anticipated expiration: 1990-12-11

Abstract

A connector contact having two portions which are mechanically connected and electrically isolated one from the other except for an electrical path provided through a resistor which acts as a buffer between an active circuit connected to one portion and a testing device connected to the other portion.

Description

United States Patent 1 Noyes 1 Dec. 11, 1973 CONNECTOR CONTACT INCLUDING AN ISOLATION RESISTOR [75] Inventor: LeRoy W. Noyes, Milwaukee, Wis.

[73] Assignee: General Motors Corporation,

Detroit, Mich.

221 Filed: Nov. 26, 1971 211 Appl. No.: 202,320

[52] 0.8. CI. 339/147 R, 338/220, 339/276 T,

339/278 C [51] Int. Cl H01r 11/08 [58] Field of Search 313/136, 137;

[56] References Cited UNITED STATES PATENTS 2,894,205 7/1959 Schrock et a1 324/725 2,508,354 5/1950 Brinson 315/58 X 3,111,641 11/1963 Wilentchik... 3,191,133 6/1965 Texsier 339/26 Primary Examiner-Richard E. Moore AttorneyEugene W. Christen et al.

[57] ABSTRACT A connector contact having two portions which are mechanically connected and electrically isolated one from the other except for an electrical path provided through a resistor which acts as a buffer between an active circuit connected to one portion and a testing device connected to the other portion.

1 Claim, 4 Drawing Figures CONNECTOR CONTACT INCLUDING AN ISOLATION RESISTOR The invention herein described was made in the course of work under contract or subcontract thereunder with the Department of Defense. This invention relates to electrical connector contacts and more particularly to a connector contact including an isolation resistor as an integral part of its assembly.

In the design of various functional circuits, which are fabricated into printed circuit boards, test points are often interfaced to external test equipment in order that primary voltages or current can be monitored. These test points may be the outputs of a digital frequency divider or the analog output voltage of an amplifier. In order to prevent degradation of performance of the active circuit and to insure that these test points are not accidently grounded by inadvertently shorting the test point, it is conventional practice to incorporate a series buffer resistor between the test points and the external test equipment. This is usually accomplished by physically placing a resistor of sufficient value on the circuit board and providing printed circuit runs from the point which is to be monitored through one end of the resistor and from the other end of the resistor to the-circuit cards motherboard connector. The motherboard connector wire harness then may be interfaced with the necessary test equipment via a test connector contact. Thus the series connection of the buffer resistor between the test point and the test connector contact is accomplished.

Because of the many test points needed for monitoring the electronics associated with large electronic systems a separate circuit board entirely devoted to the buffer resistors is often required which necessitates additional mounting space within the structure carrying the electronic system.

It is an object of the present invention to eliminate the need for such buffer resistor board and the additional mounting space by providing the necessary buffer resistor as an integral part of the connector contact.

Other objects and advantages of the present invention will be more apparent from the following detailed description which should be read in conjunction with the drawings in which:

' FIG. I shows a partially cut away view of the connector contact of the present invention;

FIG. 2 is a sectional view taken along lines 22 of FIG. 1;

FIG. 3 is a top view taken along lines 3-3 of FIG. 1;

FIG. 4 is an exploded view of the connector contact of the present invention.

Referring now to the drawings, where like numerals designate corresponding elements in the various figures, a preferred embodiment of the present invention is shown to comprise an inseparable socket contact including a contact portion and a lead portion 12 for interconnecting a testing device and an active circuit respectively. The contact portion 10 includes a female contact 14 adapted to receive a male contact within the confines indicated in part by the dotted lines 16. The contact 14 has a bored end portion designated 18 and including a seat 20. The lead portion 12 includes a lead barrel 22 of outside diameter substantially the same as the outside diameter of the bored end portion 18 for mechanically and electrically attaching an electric lead. The lead barrel 22 includes an opening 24 provided for the purpose of plating the inside of the barrel 22 with a conductive and protective material such as gold. The electrical connection between the lead and the lead barrel 22 is normally obtained by crimping the barrel 22 to the lead. The portion 12 is also provided with a seating and retaining shoulder 26 of greater diameter than the lead barrel 22 and which is adapted to cooperate with suitable tines located in the connector assembly to thereby releasably secure the connector contact in the connector assembly. The portion 12 further includes a stub shaft end portion 28 of diameter less than the internal diameter of the bored end portion 18. A resistor element 30 is affixed to the stub shaft 28 and the seat 20 by means of a suitable electrically conductive cement or solder. After assembly of the

portions

10 and 12, a flowable dielectric 32 is injected through an opening 34 in the bored end portion 18 to electrically isolate the end portion 18 from the resistor 30 and stub shaft 28 and flows between the bored end portion 18 and the shoulder 26 to form a band 36 electrically isolating the portion 18 and the shoulder 26. The resistor 30 thus provides the only conductive path between the contact 14 and the lead barrel 22 and serves as a buffer between the active circuit connected to the portion 12 and the testing device connected to the portion 10. 7

While the invention has been described with regard to an embodiment including a female contact portion 10 it will be appreciated that a male contact could be employed where such is desirable.

I claim:

1. A connector contact assembly including first and second contact portions for electrically interconnecting first and second external circuits respectively, said first portion having a bored end portion of predetermined external and internal diameter, said second portion having a lead barrel adapted to be connected to an electrical lead and of external diameter substantially corresponding to the external diameter of said bored end portion, said second portion further including a stub shaft end portion of less diameter than the internal diameter of said bored end portion and a shoulder portion of greater diameter than said lead barrel and interposed between said lead barrel and said stub shaft, a resistor element affixed to said stub shaft and the seat of said bored end portion to establish an electrically conductive path between said first and second portions, and a dielectric material electrically isolating the sides of said bored end portion from said stub shaft, said resistors and said shoulder, said bored end portion having an opening in the sides thereof through which said dielectric material may be introduced.