US2308324A - Electrical connector and method of manufacturing the same - Google Patents

Description

Jan. 12, 1943. G. B. BENANDER Filed July 10 '1940 Inventor: I George Benander His Attorney. A

//////ZHL I ELECTRICAL CONNECTOR AND METHOD OF MANUFACTURING THE SAME Z Patented Jan. 12, 1943 ELECTRICAL CONNECTOR AND METHOD OF MANUFACTURHVG THE SAME George B. Benander, Oaklawn, R. L, assignor to The Monowatt Electric tion of Connecticut Corporation, a corpora- Application July 10, 1940, Serial No. 344,742

4 Claims.

The present invention relates to electrical connectors comprising a casing of insulating material having contact members embedded therein connected to electrical conductors, and passages leading to the contact members for the reception of the uprights or blades of an electric plug.

It is now well known to construct electric plug connectors comprising an insulating body of molded rubber in which the inner ends of the uprights or blades are embedded and to which the conductors of an electric cord are connected, the outer ends of the uprights or blades projecting beyond the body and being of a size and so spaced'that they may be inserted into engagement with the contacts of a connector or receptacle. Such plug connectors having bodies of molded rubber have well recognized advantages and it has been appreciated that it was desirable to similarly construct electrical connectors. However, for such electrical connectors, the Underwriters requirements are diilicult to meet inasmuch as it is required that a connector for an 110 volt circuit shall withstand 1000 successive connections and disconnections at 250- volts. 15 amperes. Connectors having molded rubber bodies have been constructed which meet these requirements but they have been relatively complicated and expensive to manufacture.

The object 01 the present invention is to provide an improved electrical connector which, while simple in structure and capable of being manufactured at low cost, will meet the Underthe degree of hardness oi the rubber may vary 7 according to the requirements to which the conwriters requirements, and to provide an improved method of manufacturing the same.

For a consideration of what I believe to be novel and my invention, attention is directed to the following specification and the claims appended thereto;

In the accompanying drawing, Fig. 1 is a vertical sectional view on line l-i, Fig. 2, of an electrical connector embodying my invention; Fig. 2 is a top plan view of the electrical connector; Fig. 3 is a sectional view of a pre-molded rubber casing used in constructing an electrical connector embodying my invention; Fig. 4 is a sectional detail view illustrating the method used inconstructing my improved connector, and Fig. 5 is an exploded view further illustrating the method of manufacture.

Referring to Figs. 1 and 2, the electrical con- 0 nector comprises a body I of molded rubber having recesses 2 in which are located the electrical contacts 3. The molded body I is preferably molded of rubber of a degree of firmness so that the body is reasonably pliable, although nector is to be put. Each contact '3 comprises a longer outer leg 4 and a shorter inner leg 5, the two legs being integral with each other and ,being embedded in the body and spacedapart sufliciently to receive the uprights or blades of a plug connector or attachment plug. The openings 2 are of a width equal to the width of the uprights or blades of a standard plug connector, the outer ends The outer ends of the contacts are spaced back from the face 1 of the body nd each end is bent at an angle as shown at 8 and 9, such ends being embedded in the material of the body to hold the contacts in place. In indicates an electric cord which may be of any suitable type and has two conductors, the bared ends of which are connected to the inner ends of the contacts as indicated at H. As shown particularly in Figs. 1, 4 and 5, the bared ends of the conductors are inserted betweenthe inner ends of the contacts and may, ii! found place.

Referring particularly to Fig. 1, it will be noted that the outer ends of the outer contact legs. I terminate at a point beyond the outer ends of the, inner legs 5 so that when the blades of an attachment plug are pulled from engagement with the contacts, the circuit is finally broken at the 4. Also, it the contact terminate well below the surface I f the connector body, thus providing a region above each contact which forms an arc snufling space or chamber. As a result, when an electrical attachment plug is removed from the connector, the plug blades separate from the contacts at the upper ends of the outer contact arms 4 so that the length of the path between the contacts where the break occurs is a maximum. This tends to prevent iiashover between the contacts. Also, the spaces Q above the contacts, which spaces are of the size of the attachment plug uprights, serve to con-- 6 of the openings corresponding in dimensions to the dimensions of such uprights.

desirable, be spot welded. in

proved arrangement whereby I have increased the length of the path between the contacts and provided are confining and snumng chambers. I have eliminated the carbonizing effect on this portion of the connector to an extent'such that difficulty is not experienced from this cause.

In constructing my improved connector, I follow preferably the following method:

I first mold from suitable rubber a casing M as shown in perspective in Fig. and in section in Figs. 3 and 4. This casing has a circular opening l5 at its lower end through which the conductors enter and a rectangular opening l6 which extends down from the upper end of the plug and terminates at its lower end to form shoulders I'I. At the central portion, the rectangular opening is enlarged to form a circular passage as indicated at III, which passage i in line with the opening I5. Opening I8 is of a width equal to the width of the contacts 3. After casing II has been formed, the contacts 3 with the conductors in attached are assembled in the casing as shown in Fig. 4 and the casing is placed in the cavity ii! of the mold part 2|, this being a stationary part of a suitable mold which may be a single cavity mold or a muiti cavity mold. The contacts 3 are of a width equal to that of opening l6 so that they fit snugly therein. They are located with their innerends against shoulders I'l. Since contacts 3 are of a width equal to that of opening It, the sides of the opening serve to seal or enclose the space between legs 4 and i of the contacts.

In assembling the contacts and casing,the wire in may be first passed through the casing 14, as shown in Fig. 5, and the ends of the bare conductors connected tothe inner ends of the "contacts, as shown in Fig. 5, after which the contacts may be pulled down into the casing to the positions shown in Fig. 4. The. mold is shown as being provided with a side-opening a for the insertion of the wire 10.

Next the movable mold member 2|, which is provided with two rectangular pins 22 of a size in transverse section equal to that of passages 6, is closed on the lower mold part 20, as shown in Fig. 4, the pins entering the spaces between the legs 4 and B of contacts 3, thus sealing the openings between their outer ends and forcing the outer arms 4 firmly against the adjacent surfaces of the casing I4 and embedding the outturned ends of the arms in the material of the casing. The mold member 2| has a central opening 23 and next a plug 24 of uncured rubber or other suitable uncured molding material is'inserted in this opening, after which the mold plunger 25 is lowered to force the material of plug 24 into the opening (6 between the contacts and down into opening l5, entirely filling such openings and embedding the contacts, a portion of the cord III which lies in opening l5, and the connections between the conductors and the contacts in'the material of the plug. The result is a substantially solid integral structure, as

. shown in Fig. 1. Since the contacts 3 fit snugly in opening I6 and pins 22 close the spaces between the arms of the contacts at their outer ends, no rubber can getintqthe spaces between such legs.

The mold is suitably heated and after the material of the plug has been cured, the mold is opened and the finished electrical connector is removed.

When the mold is opened, pins 22 are withdrawn from the molded body, leaving the passages 6 leading to the contacts 3, which passages are of a size in cross-section to receive the uprights or prongs of a plug connector.

In the drawing, the mold is shown only diagrammatically, the supports and operating mechanism being omitted as this forms no part of the present invention. Moldsof this type are known and in carrying out the invention, any suitable mold structure may be used.

From the foregoing, it will be seen that my invention may be carried out by'use of a simple mold structure and that the only parts required in constructing the connector are the outercasing, the two connectors, and the plug insert. In manufacture, the parts 'can be quickly assembled and placed in the mold.

What I claim as new and desire .to secure by Letters Patent of the United States, is:

1. The method of manufacturing an electrical connector which comprises forming a casing of moldable material having a rectangular opening, inserting contacts each'comprising spaced contact arms of a width equal to that of the opening into the opening at opposite ends thereof and with their outer ends below the face of the casing. placing removable rectangular pins in the spaces between the arms 'ofthe contacts, said pins being of a size'such as to fill such spaces and force the outer of the spaced contact arms into the material of the outer side walls of the rectangular openings, filling the portion of the opening between the contacts with moldable material, and then removing said pins.

2. The method of manufacturing an electrical connector which comprises forming a casing of moldable material having-a rectangular opening with shoulders at its lower end, and a second opening for the passage of conductors, inserting contacts each comprisingspaced contact arms of a width equal to that of the rectangular opening andhaving conductors extending through vsaid second opening attached thereto into the rectangular opening at opposite ends thereof and with their inner ends resting'on said shoulders and their outer ends below the face of the casing, placing removable rectangular Pins in the spaces between the arms of the contacts, 'said pins being of a size such as to fill such spaces and force the outer of the spaced contact arms into the material of the outer side walls of the rectangular openings, filling the portion of the opening between the contacts with moldable material and then removing said pins.

3. The method of manufacturing an electrical connector which comprises forming a casing of moldable material havinga rectangular opening with shoulders at its lower end, and a second opening forthe passage of conductors, insertin contacts each comprising spaced contact arms of a width equal to that of the rectangular opens ing and having conductors extending through said second opening attached thereto into the rectangular opening at opposite ends thereof and with their inner ends resting on saidshoulders and their outer ends below the face of the casing, the free ends of said contact arms havingoutwardly turned ends, placing .removable rectangular pins in the spaces between the arms of the contacts, said pins being of a size such as to fill such space and force the outer of the spaced contact arms into thematerial -of the outer side walls of the rectangular openings, filling the portion of the openings between the contacts with moldable material and'in which the outwardly turned ends of the inner contact said body at a point remote from the open ends 0! said passages, bared ends of the conductors of said cord being connected to the inner ends of said contacts whereby the outer ends of the contacts are free of cord connecting means, the outer ends of the arms of said contacts being spaced back from the outer open ends of the passages to form are snufling chambers and the free end of the outer arm of each contact extending beyond the free end of the inner arm I to provide an arcing gap of maximum length between the contacts.

GEORGE B. BENANDER.

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