US3673549A

US3673549A - Fully insulated quick disconnect

Info

Publication number: US3673549A
Application number: US41998A
Authority: US
Inventors: Ward L Bliley
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; ITT Inc
Priority date: 1970-06-01
Filing date: 1970-06-01
Publication date: 1972-06-27
Anticipated expiration: 1989-06-27
Also published as: CA948288A; FR2095733A5; GB1299825A

Abstract

Quick disconnect connectors are provided which are fully insulated. A thin wall tubing having a wall thickness of from about 0.0005 to about 0.005 inch is employed to provide full insulation of the electrical connector terminal. No secondary operations are required to achieve full insulation and standard crimping dies can be used.

Description

United States Patent Bliley [451 June 27, 1972 [54] FULLY INSULATED QUICK DISCONNECT [72] Inventor: WardLBllley, Chesterland, Ohio [73] Assignee: International Telephone and Telegraph Corporation, New York, NY.

[22] Filed: June 1,1970

[21] Appl.No.: 41,998

[52] US. Cl. ..339/220 R, 339/213 T [51] Int. (1 H0lr 9/08 [58] Field of Search ..339/59, 217, 220, 213, 276,

339/223, 256 SP, 258 S; 174/DIG. 5

[56] References Cited UNITED STATES PATENTS 10/1946 Watts ..339/213 Gonankiewicz ..339/95 3,356,987 l2/l967 Gi1lespie.. 33 9L2 23 FOREIGN PATENTS OR APPLICATIONS 743,256 9/1966 Canada ..339/258S 267,609 5/1966 Australia ..339/223R Primary Examiner-Richard E. Moore Assistant Examiner-Robert A. Hafer Attorney-C. Cornell Remsen, .lr., Walter J. Baum, Paul W. Hemminger, Charles L. Johnson, Jr., Delbert P. Warner and James B. Raden ABSTRACT Quick disconnect connectors are provided which are fully insulated. A thin wall tubing having a wall thickness of from about 0.0005 to about 0.005 inch is employed to provide full insulation of the electrical connector terminal. No secondary operations are required to achieve full insulation and standard crimping dies can be used.

10 Chins, 5 Drawing Figures FULLY INSULATED QUICK DISCONNECT This invention relates to quick disconnect connectors. More particularly, it relates to fully insulated terminals for quick disconnect connectors.

The term quick disconnect connector" is a generic name for a well known electrical connector product. The terminal member of such a connector has a rolled connector body with an integral ferrule or barrel attached thereto. In assembly, an electrical wire is inserted into the barrel portion of the terminal and is crimp connected into position. The ferrule or barrel has an insulated sleeve which is positioned on a part of the connector that must be crimped. This insulation has specific physical qualities and dimensions in order to make a good mechanical and electrical connection. However, certain difficulties are presented by the cushioning effect which this insulating sleeve has on the crimping operation. Therefore, although this insulation is necessary to achieve the desired connection results, it must not be too thick and cannot be substantially increased in thickness.

In some instances, it is necessary to extend the insulation down over the terminal of the connector all the way to its tip end. Since the added thickness of further insulation would unduly cushion the ferrule or barrel, this added insulation cannot be tolerated. Therefore, it has been common practice to slip the insulation sleeve up over the wire before the connector is crimped. Then, after the crimp, the sleeve is slipped down over the terminal to insulate it all the way to its end. This involves a considerable amount of time consuming and relatively inefi'rcient hand labor.

In another case, the insulated sleeve is slipped up over the connector after the crimp is made. Then the sleeve is shrunk to provide the fully insulated quick disconnect terminal. This technique suffers the same disadvantage of requiring an additional operating step to provide full insulation.

Accordingly, an object of this invention is to provide new and improved fully insulated quick disconnect connectors for crimp attachment to wires.

Another object is to provide connectors which incorporate an insulation material over the ferrule or barrel which tends to cushion the crimping dies and yet provides a strong mechanical bond and a good electrical connection. In particular, an object is to provide preinsulated connectors having insulation running over the full length of the terminal, and these connectors providing mechanically and electrically reliable crimp connections to electrical wiring.

In keeping with an aspect of this invention, these and other objects of the invention are accomplished by a connector comprising a terminal member with an integral ferrule or barrel having an insulating sleeve thereon. An additional extremely thin insulating sleeve is fitted over the ferrule and terminal member of the connector. Then, this additional insulating sleeve is shrunk in place prior to crimp connecting a wire within the connector.

The above mentioned and other features and objects of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a perspective front view of a fully insulated quick disconnect connector incorporating the invention;

FIG. 2 is a perspective rear view of a fully insulated quick disconnect connector;

FIG. 3 is a cross-section horizontal view (as seen in FIGS. 1 and 2) of the fully insulated quick disconnect connector, taken along line 3-3 of FIG. 2;

FIG. 4 is a cross-section vertical view (as seen in FIGS. 1 and 2) of the full insulated quick disconnect connector, taken along line 4-4 of FIG. 2;

FIG. 5 is a view similar to FIG. 4 showing a second embodiment of a connector incorporating the invention.

The fully insulated, quick disconnect connector 20 is best seen in FIGS. 1 and 2. This connector may be initially stamped from a sheet of brass or other suitable spring material. Then it is further formed to have a ferrule or barrel 21 on one end and a double rolled spring clip terminal 22 on the other end. This construction is well known in the art as a quick disconnect connector.

The ferrule or barrel 21is covered by a fairly thick insulation sleeve 23 which may be constructed from a variety of well known materials. This first crimp insulation 23 over the ferrule or barrel 21 is absolutely required at this point, and it must be relatively thick. However, the insulation cushions any crimping forces applied over the ferrule or barrel to complete the connection. Hence, the insulation has a maximum limit which cannot be exceeded if the crimp is to be made in a mechanically and electrically reliable manner. Therefore, no substantial additional thickness can be tolerated for a secondary insulating sleeve to insulate the spring clip terminal end 22.

Although fully insulated quick disconnects are in general use, heretofore, the secondary insulation for a terminal has been applied after crimping a terminal to a wire. In some cases, a plastic tubing is slid over the wire until after the crimp and then it is slid back over barrel 21 and terminal 22. Then forming the insulating material. This method requires special crimping dies in addition to expensive tooling to mold or form the insulating material to give the required fit.

I have found that a very thin wall tubing 25 can be used successfully as a secondary insulating sleeve to produce fully insulated, quick disconnect connectors. The wall thickness of the tubing 25 should be in a range of from about 0.0005 to about 0.005 inch. The very thin secondary insulating sleeve tubing 25 is applied over the crimp insulation 23 on the ferrule or barrel 21. This crimp insulation 23 is usually a material such as polyvinyl chloride, nylon or the like and may include a metal ferrule.

When the wall thickness of the tubing 25 is between about 0.0005 to about 0.005 inch, the ferrule or barrel 21 having the tubing 25 thereon may be crimped to a wire in the usual manner. Thus, the secondary operations normally required for producing fully insulated terminals are eliminated.

The ratio of the thickness of the two insulations should be about 0.0005 0.005 inch for tube 25 to about 0.014 0.045 inch for the crimp insulation 23. An additional advantage of the present construction is that standard crimping dies can be used.

Many insulating materials may be employed as the tubing 25 so long as they meet the dimensional requirements. However, I prefer to use a polyester heat shrinkable tubing. A particularly advantageous material for use herein is a polyethylene terephthalate product sold by Minnesota Mining and Manufacturing Corporation under the company designation IX-6004. This polyethylene terephthalate material is extremely well suited for use herein because it possesses the following characteristics:

low cost; ease of installation by automatic high speed machinery; fast, low temperature heat shrink fit;

high dielectric strength; semi-transparent and available in tinted hues for proper color coding.

Despite the suitability of polyethylene terephthalate, and other insulating material having the same ratio of wall thickness (i.e., about 0.0005 to 0.005 inch full insulation to about 0.014 to 0.045 inch crimp insulation) may be used if the electrical insulation characteristics are met.

To manufacture the inventive fully insulated quick disconnect connector 20, the usual partially insulated tenninal is made in a normal manner. After the polyvinyl chloride, nylon, or the like crimp insulation 23 is applied to the ferrule or barrel 21, a machine slides a piece of tubing 25 of suitable dimension over both the terminal 22 and the insulated ferrule or barrel 21. Then, the machine heat shrinks the insulation tubing 25 to a tight fit. In a preferred embodiment of my invention, the wall thickness of the heat shrunk tubing 25 should be between about 1:10 and 1:6 as thick as the crimp insulation 23. The connector 20 may then be used in a simple and expeditious manner. The end user simply inserts a wire into the ferrule or barrel 21 of the connector 20 and uses standard crimping dies to crimp connect the wire in position in the connector 20.

Occasionally, the insulation tube 25 may be slightly pierced by the crimping dies. This condition is acceptable in the crimp area, since insulation is provided by the crimp insulation 23. In fact, for a lower cost insulation, the thin wall insulation 25 need not extend beyond the terminal area 22 and into the crimp area about the ferrule or barrel 21. This reduces the amount of insulating material required.

A second embodiment is shown as insulated connector 20' in FIG. 5. This connector uses a ferrule or barrel 21 with double rolled spring clip 22 both identical and interchangeable with those shown in FIGS. 1-4. In this embodiment, the very thin secondary tubing 25 is applied directly to the ferrule 21 and clip 22 as an inner insulating sleeve. This tubing has its thickness within the range previously described for FIGS. 1-4. The tubing may be shrink-fitted in place and the thick crimp insulation 23' is slid over the ferrule 21. The connector 20' is then fully insulated and ready for use in the manner previously described for the embodiment of FIGS. 1-4.

While the principles of the invention have been described above in connection with specific apparatus and applications, it is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

1 claim:

1. A quick disconnect connector comprising a terminal member with an integral ferrule at one end thereof, said ferrule having a crimp insulation sleeve extending thereover, said crimp insulation sleeve having a wall thickness of between about 0.014 to about 0.045 inch, and a second insulating sleeve extending over said ferrule and said terminal member, the thickness of said second insulating sleeve being in the range of from about 0.0005 to about 0.005 inch.

2. The connector of claim 1 wherein said crimp insulation sleeve is constructed of a material selected from the group consisting of nylon and polyvinyl chloride.

3. The connector of claim 1 wherein said second insulating sleeve is constructed of a heat shrinkable material.

4. The connector of claim 3 wherein said second insulating sleeve is constructed of a polyester material.

5. The connector of claim 4 wherein said second insulating sleeve is constructed of polyethylene terephthalate.

6. The connector of claim 3 wherein the ratio of the wall thickness of said polyester second insulating sleeve to said crimp insulation sleeve, after heat shrinking, is in the range of from about 1:10 to 1:6.

7. A quick disconnect connector comprising a terminal member having a first insulating sleeve and a second insulating sleeve, one of said sleeves extending over the other of said sleeves, the total thickness of said first and second insulating sleeves being in the range of from about 0.015 inch to about 0.050 inch and the ratio of the wall thickness of said second insulating sleeve to said first insulating sleeve being in a range of from about 1:2.8 to 1:90.

8. The connector of claim 7 wherein said first insulating sleeve covers said second insulating sleeve.

9. The connector of claim 7 wherein said second insulating sleeve covers said first insulating sleeve.

10. The connector of claim 7 wherein said first insulating sleeve is constructed of a material selected from the group consisting of nylon and polyvinyl chloride and said second insulating sleeve is constructed of a l eat shrinkable material.

Claims

10. The connector of claim 7 wherein said first insulating sleeve is constructed of a material selected from the group consisting of nylon and polyvinyl chloride and said second insulating sleeve is constructed of a heat shrinkable material.