US3380141A

US3380141A - Contact terminal extraction tool

Info

Publication number: US3380141A
Application number: US526533A
Authority: US
Inventors: Rofer David
Original assignee: Deutsche ITT Industries GmbH
Current assignee: TDK Micronas GmbH; ITT Inc
Priority date: 1966-02-10
Filing date: 1966-02-10
Publication date: 1968-04-30
Anticipated expiration: 1985-04-30
Also published as: BE693891A; DE1640514A1; GB1130985A; SE302798B; DE1640514B2

Description

April 30, 1968 D. ROFER 3,380,141

CONTACT TERMINAL EXTRACTION TOOL Filed Feb. 10, 1966 44 I jg 2 10 Z 2&4 J06 .ZZ/vEA/rak.

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United States Patent 3,380,141 CONTACT TERMINAL EXTRACTION TOOL David Rofer, Monterey Park, Calif., assignor to International Telephone and Telegraph Corporation, New York, N.Y., a corporation of Maryland Filed Feb. 10, 1966, Ser. No. 526,533 6 Claims. (Cl. 29-403) ABSTRACT OF THE DISCLOSURE A contact terminal extraction tool having a forward cylindrical section for insertion into the bore containing the terminal and proportioned to disengage locking tangs retaining the terminal locked in the terminal block. An adjoining section of the tool is proportioned to be resiliently expanded as it is pressed over the end of the enclosed terminal, thus permitting extraction of the terminal without damage.

This invention relates to electrical connectors and more particularly to a unique tool for removing a certain type of connector contact terminal from an insulation body.

In United States Patent 3,110,093 to George S. Johnson, assigned to the same assignee as the present invention, there is disclosed an electrical connector of the type wherein one or more contact terminals, each connected to a wire, are inserted into terminal receiving bores in an insulation body after the connector has been otherwise completely fabricated or assembled. The connector includes a retaining clip or other locking means between the individual contact terminals and their respective bore walls for retaining the terminals in their operative positions in the insulation body. The Johnson patent also discloses a suitable tool for insertion into a clearance between the contact terminal and the insulator to disengage the locking device and thereby permit manual withdrawal of the terminal from the insulator by pulling on the wire attached to the contact. While this arrangement works admirably when such a wire is present, the tool is ineffective for an unwired terminal in that the wire receiving portion of the terminal normally does not extend beyond the exterior surface of the insulation body to permit the terminal to be gripped for withdrawal.

One means of removing such a unwired terminal is to insert the removal tool of the type described in the above referenced patent to release the locking means and then extract the terminal by pushing on the opposite end of the terminal. One difiiculty of such approach is that the connector must be separated from its mating member and hence when remated circuitry checkout for each terminal may be required. This problem can be quite significant when it is realized that an individual connector may have a very large number of terminals.

Another difiiculty of this pushing approach is that in applications where connectors are wall mounted, two persons are required to removethe unwired terminal, in that one person must be on each side of the wall. Moreover, in many instances both sides of a wall mounted connector are not readily accessible.

A third difiiculty of this method is that certain terminals and the surrounding insulation body are of such construction that the terminal disappears beneath the face of the insulator before it is completely accessible from the other side of the connector. Hence, it is necessary to insert a suitable tool into the bore surrounding the terminal to apply further axial force which is awkward and inconvenient with miniature components.

It is also possible to remove an unwired terminal by pressing a rod into the wire receiving cylindrical portion typically found on the rear of a terminal, the rod thus simulates a wire so that a release tool of the type described in the above referenced patent can then be used. However, this is not very satisfactory in that if the rod is metallic, it tends to deform the end of the terminal and to damage the plating. If the rod is plastic, it is not durable. Also, removal of the rod from the terminal, once the terminal is extracted, is extremely difficult and cumbersome.

Accordingly, it is a primary object of this invention to provide a unique contact terminal removal tool which overcomes the aforementioned difficulties.

It is a further object of this invention to provide such a tool which is inexpensive, simple to operate and highly reliable.

Briefly stated, the contact terminal extraction tool of the invention includes a tubular extraction member, an ejector rod slidably mounted within the forward portion of the tubular member and a plunger for axially moving the ejector rod. The tubular extraction member has a forward cylindrical tip section for freely receiving the outer end of an unwired terminal that is releasably lockable in a bore within an electrical connector body, the bore being sized such that the tip section of the extraction member can fit between the terminal and the bore. The extraction member further has a terminal gripping section joining the tip section and has an inner diameter which tapers from the tip section to a diameter smaller than the tip section and is also slightly smaller than the outer diameter of the rear portion of the contact terminal. In view of this diameter difference, the gripping section made of radially resilient material may be wedged onto the outer end of the terminal to grip the terminal while the outer surface of the cylindrical tip section is releasing the contact from the bore. The terminal can then be removed from the connector by withdrawing the tool, and the ejector rod may be moved axially by the plunger to force the terminal from the gripping section of the tubular extraction member.

Further features, objectives and advantages will become apparent with reference to the. following description and drawings in which:

FIG. 1 is a sectionalized side elevational view of the extraction tool of the invention;

FIG. 2 is a sectionalized view of the forward portion of the tool as it is being inserted onto the rear of a contact terminal;

FIG. 3 shows the arrangement of FIG. 2 with the tool in the fully inserted position; and

FIG. 4 is a view of the arrangement showing the tool and the terminal being withdrawn from the connector.

Referring now to the drawings for a detailed description of the invention, it may be seen from FIG. 1 that the unique tool incorporates only three elements, a tubular extraction member 10, an ejector rod 12 and a plunger 14. The member 10 has several sections of different diameters, including a cylindrical forward tip section 16, an adjoining section which tapers from the cylindrical tip sec. tion to a cylindrical section of smaller diameter, the forward portion of the smaller diameter cylindrical section taken with the tapered section forming a gripping section 18, a central transitional section 20 of still smaller diameter and a rear plunger receiving section 22 having an enlarged diameter.

In FIGS. 2-4, there is illustrated a portion of an electrical connector having contact terminals of the so-called rear release type, that is they are adapted to be inserted and withdrawn from the rear of the connector. The connector includes an insulation body 24 having a bore 26 extending therethrough from a front face 24a to a rear face 24b. Within the rear portion of the bore there is captivated a retaining clip 28 having one or more inwardly extending resilient fingers 28a which engage the rear surface of a flange 30a formed on a contact terminal 30. The contact terminal 30 is inserted into the bore 26 through the rear face 24b past the resilient retaining fingers 28a until the flange 30a has been seated on the bore shoulder 26a which permits the fingers to snap inwardly to secure the terminal 30 within the connector body. It should be understood that while only a single terminal is illustrated, a typical connector of this type is made on a very small scale and incorporates a large number of individual terminals.

Normally, the rear wire receiving socket 30b of terminal 30 is crimped or otherwise connected to a conducting wire when it is inserted into the connector 24. Hence, when removal is desired, a tubular tool of the type disclosed in the cited Johnson patent, having an axial split, may be placed over the wire and inserted into the bore to release the retaining fingers 28a and the tool and terminal may then be withdrawn by pulling on the wire. However, there are certain situations in which an unwired terminal is positioned in a particular connector. For example, a particular application for one of these connectors may not require immediate use for all of the terminal receiving bores, but yet it is necessary to close the unused bores by inserting a terminal therein to seal the connector. At a future dateit may be desirable to remove the unwired terminal and connect it to a wire.

In accordance with the invention, tubular member is adapted to be inserted into the bore 26 to surround the wire receiving socket 30b of terminal 30. The forward tip section 16 of the member is given an inner diameter a few thousandths larger than that of the socket so that section 16 will freely slip over the terminal, and the outer diameter of the tip section 16 and the adjacent gripping section 18 are such that the extraction member will fit within bore 26 and retaining clip 28. As can be seen from the drawings, the axial length of section 16 is less than that of socket 30b and is preferably equal to about one half of the axial length of the rear portion of terminal 30. Consequently, further insertion of the tool causes the cylindrical portion of gripping section 18 to be frictionally wedged onto the terminal to the position shown in FIG. 3, wherein the forward end of the extraction tool is adjacent the rear surface of flange 30a and the outer forward surface of the extraction tool has forced the resilient fingers 28a outwardly, thereby releasing the terminal from its locked condition within the connector. By virtue of this unlocking action and the frictional interference between the cylindrical portion of the gripping section 18 and the terminal, the terminal may be easily withdrawn from the connector bore as shown in FIG. 4.

Since the tip section 16 is roughly half the length of the terminal socket portion 30b, the effective length of the gripping section 18, including the tapered portion is roughly equal to or no more than that of the tip section. To provide the Wedging action while not damaging the terminal, the gripping section 18 of the extraction member must be made of a material which is radially resilient. At the same time, the extraction member should be axially rigid to withstand the pushing and pulling forces. Accordingly, the extraction member is preferably made of a thermosetting plastic or other material having similar characteristics. While it is, perhaps, only necessary that the gripping section be made of such material, from a cost and ease of manufacture standpoint it is desirable .4 that the entire unit be molded of such material. As an example of the interference involved when a thermosetting material is employed, the cylindrical portion of the gripping section is preferably from .001-.00S" smaller in diameter than the socket 30b, and because of its inherent resilience, will expand by at least this much when wedged onto the socket 30b.

During the terminal extraction operation, the ejector rod 12 secured by a suitable extension 12a to plunger 14 is completely withdrawn to the position shown in FIG. 2, wherein the shoulder formed by the diameter difference between sections 12a and the main portion of the rod engages the shoulder 20a adjacent the reduced diameter section 20 of the extraction member. When in this position, there'is adequate space within the forward end of the extraction member to receive the rear portion of terminal 30. Hence, the axial length of the rod section 12a is slightly greater than that of the wire receiving socket of the terminal, and the axial length of extraction member 10 from its forward tip to the shoulder 20a is slightly greater than the length of the rear portion of the terminal and the main portion of the ejector rod 12.

To eject the terminal from the extraction tool, it is a simple matter to depress the plunger 14 causing the ejector rod to axially move forwardly to engage and to force the terminal from the gripping section 18. The tool is shown in this ejection position in FIG. 1. Since the ejector rod is relatively slender, it is fabricated from a metallic alloy to have adequate durability and to be of sufficient columnar strength to preclude its buckling or bending. Note that in this position, the forward end of the rod is approximately flush with the front of the tool tip and that the length of the plunger is slightly longer than the length of the plunger receiving section 22 so that the head of the plunger is spaced from the rear of the extraction member to prevent pinching of the operators hand.

Thus, it can be seen from the foregoing description that the invention provides a unique, but highly reliable and inexpensive type tool for extracting unwired terminals. Although a specific embodiment of the invention has been illustrated, it is intended that any variations or modifications falling within the true spirit or scope of the invention are to be included in the appended claims.

What is claimed is:

1. A contact terminal extraction tool for use in connection with an unwired contact terminal of the type that is releasably lockable in a bore within an electrical connector body, and its outer end is spaced from the surrounding bore, said tool comprising:

a tubular extraction member having a tip section for insertion in said bore and for freely receiving the outer end of said terminal;

a terminal gripping section joining said tip section and including a section having a tapered bore of gradually diminishing internal diameter which merges with a cylindrical bore having an internal diameter smaller than the tip section diameter;

said gripping section being radially resilient so that the cylindrical bore portion thereof may be wedged onto the outer end of said terminal to grip the terminal as the outer surface of said tip section is releasing the terminal from said bore;

and an ejector rod slidably mounted within said tubular member for engaging the end of said terminal after it has beeen removed from said connector body and for axially forcing the terminal from the grip of said gripping section to eject the terminal from said tubular member.

2. The invention of claim 1, including plunger means slidably mounted in the rear section of said tubular extraction member to apply axial force to said ejector rod.

3. Theinvention of claim 2 in which said plunger means has an enlarged rear portion extending out of said tubular member to provide a surface on which the user of the tool may apply axial force.

4. The invention of claim 1 wherein the axial length of said tip section is approximately equal to the axial length of (the working portion of) said gripping section.

5. The invention of claim 1 wherein the diameter of the forward portion of said ejector rod is slightly less than that of the diameter of said cylindrical bore portion of the gripping section.

6. The invention of claim 1, including shoulder means formed within said extraction member to limit the rearward movement of said ejector rod and when said rod is in its rearwardmost position the forward end of the ejector rod is positioned to the rear of said gripping section so that an adequate space exists in the forward end of the extraction member for receiving the outer end of said terminal.

References Cited UNITED STATES PATENTS 3,075,283 1/1963 Jansch 29-206 3,210,832 10/ 1965 Kalen. 3,210,836 10/1965 Johanson et a1 29--278 12/ 1965 Camargo.

THOMAS H. EAGER, Primary Examiner.