US3296577A

US3296577A - Electrical connector assembly and method

Info

Publication number: US3296577A
Application number: US405341A
Authority: US
Inventors: Lawrence R Travis; Robert A Ramey
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1964-10-21
Filing date: 1964-10-21
Publication date: 1967-01-03
Anticipated expiration: 1984-01-03

Description

1967 R. TRAVIS ETAL 3,296,577

ELECTRICAL CONNECTOR ASSEMBLY AND METHOD Filed Oct. 21, 1964 L a wrence 1?. no wk and Robert A. Ra mey k wwa United States Patent 3,296,577 ELECTRICAL CONNECTGR ASSEMBLY AND METHOD Lawrence R. Travis and Robert A. Ramey, Monroeville, Pa., assignors to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 21, 1964, Ser. No. 405,341 6 Claims. (Cl. 339-275) The present invention relates to electrical connector assemblies, and more particularly to electrical connector assemblies for soldering together an electrical conductor and a female type of connector.

Numerous electrical connector assemblies have been devised for soldering together an electrical conductor, usually a wire having a circular cross-section, and a female type of connector contact or terminal. One of the most common systems is that of inserting a wire into a solder cup type of female connector which has a relatively large cross-section compared to that of the wire and then applying solder and heat to the assembly to complete the connection. The difliculties with this system are: the solder provides the complete connection between the wire and the female conductor, the use of the solder cup type of connector introduces a large amount of solder around the wire which may create voids or pockets in the solder and thereby affect the electrical conductivity of the connection, and a relatively long time is required for making such a connection because of the number of steps involved. Moreover, if a large number of connections are to be made within a limited area difficulty may be encountered in completing the array using the above method. Another frequently used connector assembly is that of a solderless or pressure type of connection in which the conductor and connector are secured together mechanically, for example by crimping, or by placing a band about the conductor and connector. Since the conductor and connector are held together merely by physical pressure contact, a relatively poor electrical connection may be obtained. Moreover, because of forces being applied'to the crimped or secured mechanical connection and perhaps thermal cycling of the connection, the pressure of the connection eventually may become reduced to the point of perhaps being open circuited. Various other systems of either providing a solder connection or a mechanical connection between a conductor and a female type of connector have been suggested, however, these also present all or at least some of the attendant problems as discussed above.

Another problem of presently used solder connector assemblies is that of removal of the connection. This is especially prevalent when high density female connectors are utilized. In the solder cup connector, breaking the connection is particularly difficult. With a pressure connector the removal process is easier, however, a relatively unreliable electrical connection is obtained.

It is therefore an object of the present invention to provide a new and improved electrical connector assem bly and a method of providing such a connector assembly.

It is a further object of the present invention to provide a new and improved electrical connector assembly utilizing both a solder and a pressure type of connection and a method of providing such a connector assembly.

It is still a further object of the present invention to provide a new and improved electrical connector assembly which provides good electrical conductivity, ease of making and breaking the connection, and high reliability, and also a method of providing such a connector assembly.

Broadly, the present invention accomplishes the above cited objects by providing an electrical connector assembly and a method for providing such a connector in which an electrical conductor is soldered to a female type of connector by utilizing in combination a pressure connection and a solder connection. Specialized soldering ap paratus is utilized in one embodiment in order to enhance the speed of making and breaking of the connection.

These and other objects and advantages of the present invention will become more apparent when considered in view of the following specification and drawings, in which: J

FIGURE 1 is a pictorial diagram of male type electrical conductor as utilized herein;

FIG. 2 is a pictorial diagram of one embodiment of a female connector as utilized herein; j

FIG. 3 is a pictorial diagram showing the electrical conductor of FIG. 1 secured to the female connector of FIG. 2;

FIG. 4 is a pictorial diagram of an electrical conductor gripped by a soldering tool;

FIG. 5 is a pictorial diagram of another embodiment of a female connector as utilized herein; and

FIG. 6 is a plan view of the gripping tip portion of the soldering apparatus as utilized herein.

Referring to FIG. 1, an electrical conductor is shown in the form of a wire 10 having a portion of its insulation 12 stripped back from the end thereof. The electrical conductor is shown as a Wire having .a substantially circular cross section, however, it may take the form of any male type of electrical connector and may also be a single or a multiple strand structure. The exposed portion of the conductor 10 as utilized herein is tinned or solder dipped to form a solder layer 11 on the conductor 10. The tinning process is performed in order to: (1) provide the necessary solder to secure the conductor to the female connector, (2) add additional mechanical strength to the conductor, and (3) coat the ends of the conductor in the case of a multiple strand wire and prevent corrosion of the copper with the solder. In certain applications, it may not be necessary to tin the conductor 10. However, in most instances best results will be obtained by tinning.

FIG. 2 shows a female connector 14, which is tubular in form with a substantially circular cross-section. 'The female connector 14 may be fabricated, for example, of a spring type of material which is tubular in cross-section, a counterbored rod or a formed stamping. The female terminal 14 has an inside diameter D, substantially identical or slightly smaller than the diameter D of the conductor 10. Two

slots

16 and 18 are cut from the open end 20 of the terminal 14 on opposite sides of the terminal in a plane containing the axis of the terminal. I The

slots

16 and 18 may be formed by machining, stamping, or other methods, and are cut from the open end 20 a distance at least several times the diameter of the terminal toward the back portion of the connector terminal. At the end 20 the terminal 14 flares out at a flange portion 22 which permits the ready insertion of the conductor 10. Also the flange portion 22 provides a camming surface to the end 24 of the conductor 10 which will force apart the sides of the

slots

16 and 18 as the conductor 10 is inserted into the opening 20.

To secure the conductor 10 to the female terminal 14, the conductor 10 is forced into the opening 20 with the end portion 24 thereof engaging the flange portion 22 of the terminal 14. This forces apart the

slots

16 and 18 with the conductor 10 then being forced to its desired insertion length into the terminal 14. A reactive force will be asserted against the conductor 10 by the terminal 14 since the inside diameter D, of the terminal 14 between the inside wall, is originally, without insertion of the conductor 10, substantially the same or somewhat smaller than the diameter D of the conductor 10. Thus, a pressure connection will be established between the inside wall of the terminal 14 and the wire conductor 10. The spring pressure also serves to ensure a very Patented Jan. s, 1961 thin solder interface between the inside of the connector and the outside of the conductor. The connection process is completed by applying heat to the connector terminal 14 and the conductor 10 in a sufiicient amount to melt the solder layer 11 that had been previously applied to the exposed end of the conductor 10. The solder will thus melt by the well known soldering process and will adhere to the inside wall of the conductor 14 to form an excellent electrical and mechanical connection thereto.

The heat to melt the solder may be supplied by a conventional soldering tool or more favorably with resistance soldering apparatus whereby the workpiece is heated by the flow of current therethrough. Such resistance soldering apparatus is described in copending application Serial -No. 358,439, filed April 9, 1964, and assigned to the same assignee of the present application. The use of resistance soldering apparatus will be discussed in more detail with reference to the embodiment of FIGS. 4 and 5.

Considering now the embodiment of FIGS. 4 and 5, the electrical conductor of FIG. 4 is substantially the same as that of FIG. 1 having an electrical conductor with the insulation 12 stripped back from the end portion thereof. FIG. 5 shows the female terminal 14 being substantially the same as that of FIG. 2 except that the

slots

16 and 18 have a widened

frontal section

30 and 32, respectively, which extend from the front portion 20 approximately half way back the length of the

slots

16 and 18. The normal unstressed inside diameter D, of the female connector terminal 14 is again designed to be substantially the same or slightly smaller than that of the diameter D of the conductor 10. The width w of the portions and 3-2 of the

slots

16 and 18 is designed to accommodate the tip portion of a resistance soldering apparatus.

To insert the conductor 10 into the female terminal 14, the conductor 10 is gripped approximately at its midpoint between the end 24 and the insulation 12 by a pair of

gripping tip portions

34 and 36 of a resistance soldering tool as described in the above copending application. The

gripping tip portions

34 and 36 may have a contacting portion 38, as better shown in FIG. 6, which is V- shaped to act as a self-centering device as well as gripping the conductor 10. Of course, other configurations for the gripping portion 38 may be utilized depending upon the particular application. The gripping tip portion shown in FIG. 6 has such a cross-sectional dimension to permit passage through the

portions

30 and 32 of the

slots

16 and 18, and thus must be somewhat smaller than the width w, shown in FIG. 5.

With the

gripping tip portions

34 and 36 gripping the conductor 10, the conductor 10 is inserted into the opening 20 of the female terminal 14. The front portion 24 ofthe conductor 10 engages the flange portion 22 of the terminal 14, which acts to permit the ready entrance of the terminal 10 and also as a cam'ming surface to force the

slots

16 and 18 apart. The conductor 10 is then inserted into the terminal 14, the

gripping tip portions

34 and 36 being so aligned to enter into the widened

portions

30 and 32 of the

slots

16 and 18 respectively. The conductor 10 is forced into the female terminal 14 until the tip portions 3-4 and 36 engage the back portions 40 and 42 of the

slots

16 and 18. At this time, the resistance soldering apparatus is energized which will cause current to flow through the

tip portions

34 and 36 and the conductor 10 which will heat the conductor 10 and the female terminal connector 14 to melt the solder 11 which had previously been applied to the conductor 10 as described above. The melted solder will adhere to the inside wall of the female terminal 14 and provide a good electrical and mechanical connection thereto. Moreover, a good pressure connection will be provided by the cantilever action of the female terminal 14 pressing against the outside surface of the conductor 10.

The use of the resistance soldering tool provides a highly localized heat in a short time. The conductor 10 is gripped at substantially its midpoint in order to have a relatively equal distribution of heat in each direction without excessive heat being applied to the insulator portion 12 of the conductor. After the soldering process has been completed, which will be a relatively short time because of the rapid action of resistance soldering techniques, the soldering apparatus is deenergized and the

gripping portions

34 and 36 removed from the conductor 10 out and away from the

portions

30 and 32 of the

slots

16 and 18.

As in the embodiment of FIGS. 1, 2 and 3, the embodiment of FIGS. 4 and 5 provides a highly reliable con nection having a large contacting area using a combination of pressure and solder connection. The amount of solder surrounding and connecting the conductor 10 to the inner surface of the female terminal 14 is relatively small to avoid the problem of voids or pockets in the solder. Moreover, the time necessary to make the connection is relatively small, particularly if resistance heating is employed.

In the embodiment of FIGS. 4 and 5, a one-hand soldering process can be employed by inserting the wire with the gripping ti-

p portions

34 and 36 into the female terminal 14 and then energizing the soldering apparatus. This method is particularly advantageous when the terminals are closely spaced together at the rear portions of a connector array. If it is desired to remove the conductor 10 from the female terminal 14 all that is necessary that the gripping

portions

34 and 36 be inserted through the

slots

30 and 32 to engage the conductor 10. Then, the resistance heating apparatus is energized to melt the solder. The conductor 10 is removed from the female connector terminal 14 with the gripping

portions

34 and 36 passing through the

portions

30 and 32 of the

slots

16 and 18. It should also be noted that in the embodiment of FIGS. 1, 2 and 3, a removable structure is provided by heating the fem-ale terminal 14 with a suitable soldering tool and then removing the eonductor 10 when the solder has melted.

The embodiments described above have pre tinned or solder-coated the conductor '10 before insertion into the female terminal 14. However, of course, other methods of providing the solder material could be utilized. In particular, if the female terminal is a formed stamping, the inside surface of the stamping itself could be solder coated. Also, as another alternative, the conductor 10 could have a solder foil disposed therearound.

Although the present invention has been described with a certain degree of particularity it should be understood that the disclosure has been made only by way of example and that numerous changes in the details of con struction and fabrication and the combination and arrangement of parts, elements and steps of the method may be resorted to without departing from the scope and the spirit of the present invention.

We claim as our invention:

1. A connector assembly to be secured with resistance soldering apparatus having a gripping tip portion, said assembly comprising, a male conductor, a female connector including a pair of elongated slots oppositely disposed thereon in a plane and extending through an open end thereof at which the male conductor is to enter, said pair of slots having a wider width portion at the open end of said female connector-compared to the rest of the slot, said wider width portion extending a predetermined length along said slot, an abutting portion being defined in said slot at the end of said wider width portion, said wider width portion being large enough to receive the gripping tip portion of said resistance soldering apparatus, solder disposed at the desired connection area, said male conductor being inserted into said female connector by grasping said male conductor with the gripping tip portion of said resistance soldering apparatus, the gripping tip portion passing through the wider width portion of said slots in said female connector and when the gripping tip portion abuts said abutting portion of said slots said resistance soldering apparatus being energized to melt the solder to secure said male conductor and said female connector.

2. A connector assembly to be secured with resistance soldering apparatus having a gripping tip portion, said assembly comprising, a male conductor being predipped in solder for physical strength and for providing solder at the desired connection area, a female connector including a pair of elongated slots oppositely disposed thereon in a plane and extending through an open end thereof at which the male conductor is to enter, said female connector having such a diameter so that with said male conductor being inserted therein said slots being forced apart to insert a force against said male conductor, said pair of slots having a wider width portion at the open-end of said female connector com pared to the rest of the slot, said wider width portion extending a predetermined length along said slot, an abutting portion being defined in said slot at the end of said wider width portion, said wider width portion being large enough to receive the gripping tip portion of said resistance soldering apparatus, said male conductor being inserted into said female connector by grasping said male member with the gripping tip portion of said resistance soldering apparatus, the gripping tip portion passing through the wider width portion of said slots in said female connector and when the gripping tip portion abuts said abutting portion of said slots said resistance soldering apparatus being energized to melt the solder to secure said male conductor and said female connector.

3. A method of making an electrical solder connection with soldering apparatus between a male conductor and a female connector having at least a pair of elongated slots disposed thereon and extending through an open end thereof at which the male conductor is to enter, said method comprising the steps of: providing solder at the desired connection; grasping the male conductor at the opposite sides thereof with a gripping tip portion of the soldering apparatus; inserting said male conductor into said female connector with said soldering apparatus; passing said soldering apparatus while grasping said male conductor through said slots a predetermined distance; and energizing said resistance sol dering apparatus to melt the solder and secure said male conductor and said female connector.

4. A method of making an electrical solder connection with soldering apparatus between a male conductor and a female connector having at least a pair of elongated slots oppositely disposed thereon and extending through an open end thereof at which the male conductor is to enter, said method comprising the steps of: providing solder at the desired connection; grasping the male conductor at the opposite sides thereof with -a gripping tip portion of the soldering apparatus; inserting said male conductor into said female connector so that the slots thereof are forced apart to apply a reactive force to said male conductor, the slots being lined up with the gripping tip portions of said soldering apparatus; passing the gripping tip portions of said soldering apparatus while grasping said male conductor through said slots a predetermined distance; energizing said soldering apparatus to melt the solder and secure said male conductor and said female connector; deenergizing said soldering apparatus; and disengaging said soldering apparatus from said male conductor.

5. A method of making an electrical solder connection with resistance soldering apparatus between a male conductor and a female connector having at least a pair of elongated slots oppositely disposed thereon in a plane and extending through an open end thereof at which the male conductor is to enter, said method comprisin the steps of: providing solder at the desired connection; grasping the male conductor at the opposite sides thereof with a gripping tip portion of the resistance soldering apparatus; inserting said rnale conductor into said female connector so that the slots thereof line up with the gripping tip portions of said resistance soldering apparatus; passing the gripping tip portions of said resistance soldering apparatus while grasping said male conductor through said slots a predetermined distance until said gripping tip portions abut against a portion of said slots; energizing said resistance soldering apparatus to melt the solder and secure said male conductor and said female connector; deenergizing said resistance soldering apparatus; and disengaging said resistance soldering apparatus from said male conductor.

6. A method of making and breaking an electrical solder connection with resistance soldering apparatus between a male conductor and a female connector having at least a pair of elongated slots oppositely disposed thereon in a plane and extending through an open end thereof at which the male conductor is to enter, said method comprising the steps of: providing solder at the desired connection; grasping the male conductor at the opposite sides thereof with a gripping tip portion of the resistance soldering apparatus; inserting said male conductor into said female connector so that the slots thereof line up with the gripping tip portions of said resistance soldering apparatus; passing the gripping tip portions of said resistance soldering apparatus while grasping said male conductor through said slots a predetermined distance until said gripping tip portions abut against a portion of said slots; energizing said resistance soldering apparatus to melt the solder and secure said male conductor and said female connector; deenergizing said resistance soldering apparatus; disengaging said resistance soldering apparatus from said male conductor; re-engaging said male conductor through said slots with said resistance soldering apparatus at any subsequent time; energizing said resistance soldering apparatus to melt the solder; deenergizing said resistance soldering apparatus; removing said male conductor from said female connector with said resistance soldering apparatus; and disengaging said resistance soldering apparatus from said male conductor.

References Cited by the Examiner UNITED STATES PATENTS 2,691,771 10/1954 Burtt et al 339-275 X 2,810,893 10/1957 Hidde Nijland.

2,845,516 7/1958 Jones 339275 X 3,100,330 8/1963 Rice et va1. 29502 X 3,136,032 6/1964 Berndsen 29-15555 X EDWARD C. ALLEN, Primary Examiner. P. TEITELBAUM, Assistant Examiner.

Claims

3. A METHOD OF MAKING AN ELECTRICAL SOLDER CONNECTION WITH SOLDERING APPARATUS BETWEEN A MALE CONDUCTOR AND A FEMALE CONNECTOR HAVING AT LEAST A PAIR OF ELONGATED SLOTS DISPOSED THEREON AND EXTENDING THROUGH AN OPEN END THEREOF AT WHICH THE MALE CONDUCTOR IS TO ENTER, SAID METHOD COMPRISING THE STEPS OF: PROVIDING SOLDER AT THE DESIRED CONNECTION; GRASPING THE MALE CONDUCTOR AT THE OPPOSITE SIDES THEREOF WITH A GRIPPING TIP PORTION OF THE SOLDERING APPARATUS; INSERTING SAID MALE CONDUCTOR INTO SAID FEMALE CONNECTOR WITH SAID SOLDERING APPARATUS; PASSING SAID SOLDERING APPARATUS WHILE GRASPING SAID MALE CONDUCTOR THROUGH SAID SLOTS A PREDETERMINED DISTANCE; AND ENERGIZING SAID RESISTANCE SOLDERING APPARATUS TO MELT THE SOLDER AND SECURE SAID MALE CONDUCTOR AND SAID FEMALE CONNECTOR.