Connector With Isolated Ground

Abstract

A chassis mountable coaxial cable connector assembly having an isolated ground. A connector pin is attached to the center wire of the coaxial cable with insulation surrounding the connector pin to prevent unwanted signal attenuation to a housing of the connector assembly. The housing is connected to the shielding braid of the coaxial cable with the shielding braid and housing forming a floating type ground. The cable connector assembly includes a unitary constructed flanged cylinder with a threaded portion for mounting the connector assembly in a chassis and, simultaneously, isolating the housing from the chassis.

Description

BACKGROUND OF THE INVENTION

Previous to the present invention, many different types of floating ground connectors have been devised. One method of providing a floating ground for a chassis mountable coaxial connector consists of putting an insulating member in a hole through which the chassis mountable coaxial connector extends. The coaxial connector is then tightened to the insulating member with such force to retain the coaxial connector in place. The insulating member prevents the coaxial connector from touching the chassis through which it extends.

Another method that is very undesirable when a floating shield is needed would be for a coaxial connector to terminate the shield before reaching the coaxial connector housing. Another connection external to the connector housing would extend through, or around, the chassis and be connected to a shielding on the other side of the chassis through or around which the coaxial connector extends. Obviously, very high noise spikes can be radiated to the coaxial cable center conductor at the point which extends through the chassis thereby causing noise problems.

Another method that has been used to provide an isolated ground for a coaxial connector has been the enclosing of the center pin within a first insulator, then inserting the pin and insulator into the connector housing. The connector housing has a second insulating member interposed between it and a mounting bracket. During the manufacturing of the coaxial connector, one has to be very careful not to short the mounting bracket to the connector housing. If such occurs, the floating ground no longer exists, and radiated noise problems can occur. Because of the low voltage between the connector housing and the chassis, a short between the connector housing and the chassis may not be detected until it causes a failure in the system in which the connector is being utilized.

SUMMARY OF THE INVENTION

Accordingly, it is an object of this invention to provide a chassis mountable coaxial connector having an isolated ground that is more economically manufactured and reliable than the previous design.

It is a further object of the present invention to eliminate the need for additional isolation elements to prevent an electrical connection between a chassis mountable coaxial connector and a chassis into which the connector is mounted.

It is a still further object of the present invention to provide a chassis mountable coaxial connector having a single component that provides both functions of isolating the connector from the chassis and, simultaneously, securing the connector in the chassis.

It is an even further object of the present invention to provide a chassis mountable coaxial connector with an isolated ground that insures against the radiation of unwanted noise by including a sleeve portion that accomplishes both functions of mounting to a chassis and isolation from the chassis.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a sectional view of a chassis mountable coaxial connector having an isolated ground.

FIG. 2 is an exploded perspective view partially in section of the chassis mountable coaxial connector shown in FIG. 1.

FIG. 3 is an end view of the unitary constructed flanged cylinder of FIG. 1 that provides isolation and mounting of the coaxial connector.

FIG. 4 is a sectional view taken along line 4--4 of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown a coaxial connector assembly, represented generally by reference numeral 10, having an isolated ground as will be subsequently described. By referring jointly between FIGS. 1 and 2, the female connector assembly 10 will be described in detail. A connector housing 12 encloses a connector pin 14 surrounded by two sections 16 and 18 of insulating material that prevents electrical attenuation between connector housing 12 and pin 14. Insulation portion 16 is molded on pin 14 with the ribs 20 preventing subsequent rotation of the connector pin about its longitudinal axis. Thereafter, insulating portion 18 is slid over the mating portion of the connector pin 14 as shown in the assembly drawing. The two insulating portions have mating flanges 22 and 24. A rubber seal 26 which seats into a groove 28 of the connector pin 14 is used as a sealing means between insulating portions 16 and 18. After insulating portions 16 and 18 and rubber seal 26 are located on connector pin 14, they are all simultaneously inserted into the connector housing 12 in the manner as shown in FIG. 1. Thereafter, a ring 30 bonds the connector assembly together. The ring 30, which is of a force fit type, could be replaced by any other suitable means of holding the connector assembly within the housing 12.

To provide a means for mounting the connector housing 12 containing the connector pin 18 and insulation portions 16 and 18, a flanged cylinder 32, which will be subsequently described in more detail, is slid over the rear end of the connector housing 12. Looking at FIG. 1, the left-hand portion of connector housing 12 is the front and the righthand portion is the rear. After the flanged cylinder 32 is pushed on the connector housing 12 to abut the connector housing shoulder 34, all of the rear portion 36 of the connector housing 12, except a connecting tab 38, is flared outward to retain the flanged cylinder 32.

Upon insertion of the coaxial connector assembly 10 in a properly sized hole of the chassis, a washer 40 will encircle the flanged cylinder 32 adjacent the chassis. The chassis will be secured between flange 42 and retaining nut 44 which is threadably connected to a threaded portion 46 of flanged cylinder 32.

After mounting the coaxial connector assembly 10, a corresponding male coaxial connector can mate the chassis mounted coaxial connector assembly 10. A bevelled surface 48 is provided in the front of connector housing 12 to allow easy insertion of the mating connector. A protection flange 50 of insulating portion 18 surrounds tines 52 of connector pin 14. As a mating male connector is inserted, the tines 52 will flare outward to receive the male connector. Once properly mated, the outer casing of the mating connector may have slots (not shown) to receive projections 54 of connector housing 12 thereby locking the two connectors into a mating configuration. Many other types of locking devices between mating coaxial connectors may be used such as a locking thread, screw connection.

Referring now to FIGS. 3 and 4 in conjunction, the flanged cylinder 32 is shown in more detail. The flange 42 of the flange cylinder 32 has a wall 56 for abutting against the chassis into which the coaxial connector assembly 10 is mounted. Also, the smaller cylindrical portion 58 has a flat surface 60 for butting against a flat surface in the hole cut in the chassis (not shown) into which the coaxial connector assembly 10 is mounted thereby preventing rotation with respect to the chassis. The present invention shows the flange cylinder 32 as being connected to the connector housing 12 by flaring the rear portion 36 outward against bevelled surface 62 of the flanged cylinder 32. However, it should be emphasized that the present invention which uses a unitary constructed flanged cylinder 32 for both mounting and insulation purposes can be molded to the connector housing 12 or secured by any other suitable means. With newer and better plastics becoming a common part of our technology, the flanged cylinder 32 can be made from a plastic that will insulate the connector housing 12 from the chassis into which it is mounted and, simultaneously, be rugged enough to withstand the previous tests required for earlier type connectors. For example, all coaxial connector assemblies similar to that shown in FIG. 1 must withstand 15 inch-pounds of torque and 30 pounds pull as a minimum requirement. By proper design of the flanged cylinder 32, larger forces can be withstood without any damage to the coaxial connector assembly 10. It should be obvious to those skilled in the art that many other designs are possible wherein the flanged cylinder 32 is replaced by other configurations of suitable material that will provide the insulating and the mounting function as required in chassis mountable coaxial connectors. With the increase in technology, it is also possible that materials other than plastic could be used to make the flanged cylinder 32 having the insulating capabilities, plus the strength, needed for mounting a coaxial cable connector with an isolating ground.

The present coaxial connector assembly 10 does not show a feedthrough type of coaxial connector but the present design could be modified to give an isolated feedthrough connector. The rear portion of the coaxial connector assembly would have to have a means for clamping the coaxial cable in place and, simultaneously, connecting a shielding braid to connector housing 12. In such a configuration, the connecting tab 38 will no longer be required. The present design was primarily intended for use in instrument panel where the panel itself would provide the necessary shielding for the signal processing inside the panel. The floating ground feature of the present invention helps eliminate the problem of voltage potentials between different ground points for the coaxial cable, or commonly called ground loop currents.

Claims

We claim:

1. A coaxial connector with an isolated ground, said coaxial connector comprising:

a connector pin for mating with a connector to allow an electric signal to feed therethrough;

a conductive housing axially surrounding said connector pin;

means between said conductive housing and said connector pin for electrically isolating said housing from said pin, said isolation means being formed of two parts and fixed with reference to said housing;

a unitary, non-conductive cylinder having a radially extending flange on one end and a threaded section on the other end and being radially disposed about said conductive housing;

a nut engageable with said threaded section to securely mount said coaxial connector in a hole in a chassis with said non-conductive cylinder electrically isolating said conductive housing from the chassis;

an end portion of said conductive housing being deformed radially outwardly into engagement with said non-conductive cylinder to secure said cylinder in position on said housing; and

terminal means on said conductive housing providing for an electrical connection thereto to establish a floating electrical ground with respect to said connector pin.

2. The coaxial connector as recited in claim 1 wherein:

said non-conductive cylinder is made of a hard-molded, non-conducting resilient material.

3. The coaxial connector, as set forth in claim 1 wherein said unitary, non-conductive cylinder is made from a plastic that will withstand at least 15 inch-pounds torque and 30 pounds pull when mounted.

4. The coaxial connector set forth in claim 1 and further including:

a first annular electrically non-conductive member interposed between said conductive housing and said connector pin and defining one of said two parts of said isolation means;

a second annular electrically non-conductive member defining the other of said two parts and interposed between said conductive housing and said connector pin; and

fastening means operatively connected to said conductive housing and engageable with said second annular non-conductive member for holding said first and second annular non-conductive members in fixed relative positions with respect to said conductive housing.

5. The coaxial connector set forth in claim 1 wherein:

said terminal means in a tab integral with said conductive housing and extending axially therefrom.