US3618207A

US3618207A - Method of manufacturing strip connectors

Info

Publication number: US3618207A
Application number: US860148A
Authority: US
Inventors: Robert H Sand; Cecil W Libby
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1969-09-02
Filing date: 1969-09-02
Publication date: 1971-11-09
Anticipated expiration: 1988-11-09

Abstract

A METHOD OF ASSEMBLING A PLURALITY OF CONTACTS IN A CONFIGURATON SUCH AS A STRIP CONNECTOR. THE STEPS OF THE METHOD CALL FOR STAMPING OR MILLING THE MULTIPLE CONTACT CONFIGRUATION FROM A BLANK OF CONTACT MATERIAL, MOLDING A CONNECTOR HOUSING ABOUT THE CONTACTS WHILE THEY ARE STILL ATTACHED TO THE BODY OF CONTACT MATERIAL AND THEREAFTER SHEARING THE FINISHED CONNECTOR AWAY FROM THE BODY OF CONTACT MATERIAL. IN ONE VARIATION THE MILLED CONTACTS ARE PINS WHICH ARE INSERTED INTO TUBULAR CONNECTORS OR SOCKETS WHICH ARE THEN SECURED TO THE PINS BY MEANS OF MECHANICAL CRIMPING. THEREAFTER THE MOLDING STEP IS UNDERTAKEN TO FORM A CONNECTOR HOUSING ABOUT THE PLURALITY OF CRIMPED PIN-SOCKET COMBINATIONS. THE FINISHED CONNECTOR IS THEN SHEARED FROM THE BODY OF CONTACT MATERIAL AS BEFORE.

Description

Nov. 9., 1971 R. H. SAND EI'AL 3,618,207

METHOD OF MANUFACTURING STRIP CONNECTORS Original Filed Jan. 12, 1967 3 Sheets-Sheet 1 [MA E6702 F76: 2i

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INV/iN'lt/RS wifgf h. 524 0 I by (ff/77557 "United States Patent O US. Cl. 29-629 R 4 Claims ABSTRACT OF THE DISCLOSURE A method of assembling a plurality of contacts in a configuration such as a strip connector. The steps of the method call for stamping or milling the multiple contact configuration from a blank of contact material, moldmg a connector housing about the contacts while they are still attached to the body of contact material and thereafter shearing the finished connector away from the body of contact material. In one variation the milled contacts are pins which are inserted into tubular connectors or sockets which are then secured to the pins by means of mechanical crimping. Thereafter the molding step is undertaken to form a connector housing about the plurality of crimped pin-socket combinations. The finished connector is then sheared from the body of contact material as before.

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation of application Ser. No. 608,931, filed Jan. 12, 1967, and now abandoned.

SUMMARY OF THE INVENTION The present invention relates to electrical connectors and in particular to a method of manufacturing such connectors in a strip configuration.

Electrical connectors are manufactured in many configurations depending on the particular application to which the connector is to be adapted. In certain applications a connector having a plurality of contacts arranged in the form of a flat strip is desired. In other applications a plurality of connector strips of a desired contact configuration are stacked to provide a connector having several rows of contacts. In either of the preceding arrangements it is typical for the conductive pins or contacts to extend through a connector body or housing and be permanently locked in position therein. At one side of the connector the contacts are permanently connected by soldering or welding to wires or conductors extending between the connector and the equipment with which it is associated. The other side of the connector constitutes the male or female half of a connector ready for removable engagement or disengagement with a complementary connector half.

There are several methods currently in practice by which strip connectors of the type currently under consideration are fabricated. One of these conventional methods calls for assembling each connector and securing the connector thereto by means of crimping. In a separate and distinct part of the process, the connector body or housing is molded in such a manner as to provide a plurality of passages through the housing for receiving 3,618,207 Patented Nov. 9, 1971 the crimped connectors. Thereafter the crimped connector wire assemblies are inserted into the passages and sealed to the housing with epoxy or other fixative material to ltiold the connectors in position within the connector ody.

The present invention provides an improved method for forming a plurality of electrical connector halves. The method comprises the steps of forming from a sheet of conductive material an elongated conductive body having first and second opposing sides and integral therewith a plurality of conductive fingers extending from each of said sides, the step of forming the body and fingers thereby providing each of said fingers with a free end and an end fixed to one of said sides. A connector is then mechanically and electrically connected at the free end of each of said fingers such that, in combination with the finger, an individual elongated connector pin is formed having one end fixed to said conductive body and a free end. A first common insulating body is molded around all of said connector pins on the first side of said conductor body thereby securing such connector pins together and a second common insulated body is molded around all of said connector pins on the second side of said conductive body thereby securing these connector pins together. The step of molding thereby forms each of the first and second insulating bodies over the connections of the connectors and fingers leaving the fixed and free ends of the connector pins which are secured therein extending away from and exposed from such insulating body. Each of said connector pins is then severed transverse to the elongation thereof from said conductive body at a position inbetween the insulating body which secures each connector pin and the fixed end thereof, leaving the severed end of each of said connector pins extending away from and exposed from the insulating body securing each connector pin, each of said insulating bodies and the connector pins secured therein thereby forming a connector half.

One particular advantage of the above methods of fabricating strip connectors is that such methods readily lend themselves to an automatic assembly line method of production and as a consequence are more economical than the method of fabrication described above as one of the prior art methods. In addition, the automatic production equipment can be programmed to yield whatever contact configuration is desired.

The preceding and other advantages of the present invention will be better understood by reference to the following figures in which:

FIG. '1 is a block diagram illustrating the steps of a prior art method of manufacturing a strip connector;

FIG. 2 is a flow diagram showing the steps of the basic method of the present invention;

FIG. 3 is a flow diagram illustrating the steps of another embodiment of the method of the present invention;

FIG. 4 is a perspective view of a strip connector such as is used in a magnetic record and reproduce head; and

FIG. 5 is a perspective view of a stack of strip connectors mounted in a typical connector configuration.

DETAILED DESCRIPTION The steps of a prior art method of forming a strip connector are set forth in FIG. 1. As shown in the block diagram therein, the process is initiated by assembling a.

plurality of connector-contact combinations. Typically this is accomplished by inserting a wire or other metallic contact into a tubular connector and mechanically securing the connector-contact combination by a crimping operation. In a separate operation a connector body is molded in the form of an elongated strip and is provided with a plurality of passages disposed along its length in a configuration corresponding to the desired contact configuration. The connector body is removed from the mold and the individual crimped connector-contacts are inserted into the passages provided. Epoxy or other fixative material is then applied by means of syringe or the like to the areas where the connector-contacts emerge from the body passages to fix and seal them in position.

The method of the present invention can be illustrated by reference to FIG. 2 where a plan view of a connector half at various points in the process of its manufacture is shown. As shown therein, a strip of electrically conductive contact material (FIG. 2A) is obtained from a source of supply and is subjected to a suitable fabricating operation to form (as shown in FIG. 2B) a plurality of contacts or fingers 12 extending approximately transversely away from the body portion of contact material in a direction substantially transverse to the longitudinal axis of the material. The fabricating step can be accomplished in one of several ways such as mechanical stamping or chemical milling. The formed strip is thereafter introduced into a mold and suitable insulating connector body material such as Fiberite is molded transversely across the contacts .12 in the form of a continuous strip 14 disposed about the contacts and located intermediate the free and fixed ends of the contacts (FIG. 2C). The molding of the strip of connector body about contacts 12 can be accomplished in any of several of conventional ways such as injection molding. With the connector body molded directly onto the contacts the assembly is thereafter subjected to a shearing operation to separate the contacts from the body of strip material 10 at a point approximately adjacent the juncture of the fixed end of contacts 12 with the body of strip material 10. The result as shown in FIG. 2D is a pair of strip connector halves 16 having a plurality of electrical contacts 12 extending through and away from both sides of strip of insulating material 14 with the contacts oriented according to the desired contact configuration. The connectors are then read for assembly into the particular piece of apparatus with which they are to be used.

'Another embodiment of the method shown in FIG. 2 is illustrated in FIG. 3. In this embodiment a strip of electrically conductive material 18 (FIG. 3A) is again subjected to a milling operation to form a plurality of contact fingers 20 extending from the body of strip material, the fingers 20 being provided with a necked-down portion 22 at the free ends thereof (FIG. 3B). As shown in FIG. 3C, tubular connectors 24 are placed over the neckeddown portion of fingers 20 and seated against shoulders 26 at the base of the necked-down portion of the fingers.

The assembled connector-contact strip is next subjected to a mechanical crimping operation as shown in FIG. 3D to provide a secure mechanical and electrical connection between connectors and contacts. The crimped assembly is then introduced into a mold and a strip of connector body material 30 is molded across the crimped area (FIG. 3B). In FIG. 3F the molded assemblies are detached at a point intermediate the fixed ends of the fingers and the body of contact material 18 to provide a pair of strip connector halves having a plurality of contacts extending from one side and a plurality of tubular connectors extending from the other side.

Among other advantages accruing to the method of the present invention are a substantial reduction in the cost of fabricating such a strip connector due to the ready adaptability of the individual steps of the method to automatic methods. Because dimensions ultimately depend on the milling of a sheet of metallic contact material, toler- 4 ances can be reduced significantly and accuracy improved because the center to center contact dimensions are now determined by tooling tolerances in contrast with the dependence of the prior art method on the molding tolerances of the connector body.

A particular application for the strip connector assembly according to the present invention is illustrated in FIG. 4. As shown therein, a strip connector 32 comprising six groups 34 of contacts is shown ready for further assembly steps prior to incorporation into a dual gap mag netic record or reproduce head. Six magnetic cores 36 are connected to connector contacts 38 by a suitable soldering or welding operation. Tubular connectors 40 extend from the opposite side of the strip connector 32 and form the female side of a connector half. In one application the contact groups 34 are separated, stacked and mounted in a frame such as a magnetic recording head as shown in FIG. 5. The corresponding male half of a connector to which suitable cabling is connected can then be attached by engaging pins on the male half with the sockets on the female half of the connector.

What is claimed is:

1. A method for forming a pluralit of electrical connector halves comprising the steps of:

(a) forming from a sheet of conductive material an elongated conductive body having first and second opposing sides and integral therewith a plurality of conductive fingers extending from each of said sides, the step of forming thereby providing each of said fingers with a free end an an end fixed to one of said sides;

(b) mechanically and electrically connecting a connector at the free end of each of said fingers which, in combination with the finger, forms an individual elongated connector pin having one end fixed to said conductive body and a free end;

(c) molding a first common insulating body around all of said connector pins on the first side of said conductive body thereby securing such connector pins together and molding a second common insulating body around all of said connector pins on the second side of said conductive body thereby securing such connector pins together, the step of molding thereby forming each of said first and second insulating bodies over the connections of said connectors and fingers, leaving the fixed and free ends of the connector pins which are secured therein extending away from and exposed from such insulating body; and

(d) severing each of said connector pins transverse to the elongation thereof from said conductive body at a position in between the insulating body which secures each connector pin and the fixed end thereof, leaving the severed end of each of said connector pins extending away from and exposed from the insulating body securing each connector pin, each of said insulating bodies and the connector pins secured there in forming a connector half.

2. A method as defined in claim 1 wherein the step of molding forms first and second sides on each of said insulating bodies transverse to the elongation of the connector pins secured thereby with each of the connector pins extending through both of said first and second sides on the insulating bodies securing the connector pins.

3. A method as defined in claim 1 wherein the step of mechanically and electrically connecting a connector to each finger comprises the step of mechanically and electrically connecting a separate socket connector to the free end of each of said fingers.

4. A method as defined in claim 3 wherein the step of molding comprises the step of molding each of said common insulating bodies around the connector pins secured therein over the connections of each of said socket connectors to said fingers.

(References on following page) References Cited UNITED STATES PATENTS Heibel 29-627 UX Van Gessel 29630 B UX Regner 29630 B Stevens 29630' B X Lee et a1 29-627 Spiegler 29-62 7 X Van Hoof et a1. 29-627 UX 6 FOREIGN PATENTS 1,048,624 1/1959 Germany 2 9-625 JOHN F. CAMPBELL, Primary Examiner 5 R. W. CHURCH, Assistant Examiner US. Cl. X.R.