US3551613A

US3551613A - Miniature electrical contact with legs of differing mass,thickness or length for connector or switch structure

Info

Publication number: US3551613A
Application number: US834407A
Authority: US
Inventors: Theodore A Cocca
Original assignee: THEODORE A COCCA
Current assignee: THEODORE A COCCA
Priority date: 1969-06-18
Filing date: 1969-06-18
Publication date: 1970-12-29
Anticipated expiration: 1987-12-29

Description

United States Patent [72] lnventor Theodore A. Cocca Silver Spring, Md. [21] Appl. No. 834,407 [22] Filed June 18, 1969 [45] Patented Dec. 29, V [73] Assignee To the United States of America, as

represented by the Secretary of the Navy [54] MINIATURE ELECTRICAL CONTACT WITH LEGS F DIFFERING MASS, THICKNESS OR LENGTH FOR CONNECTRO 0R SWITCH STRUCTURE 8 Claims, 4 Drawing Figs.

[52] US. Cl 200/16, 200/166; 339/258 [511 Int. Cl ..'noi1ii/06, I-lOlh /00 Field of Search 200/ 1 6, 16611, 16688; 335/125, 193, 272; 339/45, 92, 258, 45

[ 56] References Cited UNITED STATES PATENTS 2,324,891 7/1943 Thumim 339/UX 2,709,794 5/1955 Johansson 339/258(F)X 2,917,612 12/1959 Chabot ..339/258(R)UX 3,362,008 1/1968 Berg 339/258 3,486,163 12/1969 De Vuyst et a1 339/258(P)X 2,077,622 4/1937 Field 200/166(H) 2,805,301 9/1957 Shaw 335/ 3,152,237 10/1964 Richert et a1. 200/166(B8) 3,290,471 12/1966 Gerardin et al... 200/16 3,296,389 1/1967 Hults 200/16 Primary ExaminerRobert K. Schaefer Assistant Examiner-J. R. Scott Attorney-J. P. Dunlavey & J. O. Tresansky PATENIED UEC29 19m NVENTOR Theodo cocca u "lib FIG. 2

PRIOR A FIG, 3

MINIATURE ELECTRICAL CONTACT WITH LEGS 01F DIFFERING MASS, THICKNESS OR LENGTH FOR CONNECTRO 01R SWITCH STRUCTURE BACKGROUND OF THE INVENTION This invention relates generally to miniature electrical connectors and more particularly to a vibration insensitive miniature electrical connector.

The use of knife blade switches as a mechanical device for effecting interruption and closure of a circuit path is well known in the art. Knife blade switches composed of a base, a female contact member, and a pivotal knife blade contact member, have been devised which provide both ruggedness and ease of manufacture.

Heretofore employed conventional knife blade switches have been bulky, however, and have not been entirely satisfactory in applications where reduced size is of major importance. The need for miniature size has led to attempts to provide reduced size electrical connectors for use as mechanical switches. Present day miniature electrical connector designs, however, have been able to provide desired operating characteristics when the connectors are subject to a high vibratory environment. More particularly, it has been found that when these miniature connectors, utilized as mechanical switches, are subject to such an environment, the female contact member surrounding the knife blade contact member, when the switch is in a closed position, has vibrated to an extent as to become disengaged from the knife blade contact. This disengagement, even if momentary, causes damaging sparking between the knife blade contact and the female contact members. Furthermore, such disengagement renders the connector in an open circuit position, which may be damaging, even if momentary, when current flow through a circuit subsequent to switch closure is required. Additionally, present day miniature electrical connectors have been unable to provide the ruggedness achieved by the older, but larger, knife blade switches. Moreparticularly, present day miniature electrical connector design has provided miniature connectors whose delicate members, such as the female contact member and the knife blade contact member, have been unprotected by a stronger member, such as a housing or the like, and, therefore, have been easily damaged by external forces.

SUMMARY OF THE INVENTION Accordingly, one object of this invention is to provide a new and improved electrical connector.

7 Another object of this invention is to provide a new and improved antivibratory electrical connector.

Still a further object of this invention is to provide a new and improved rugged miniature electrical connector.

Briefly, these and other objects are attained by providing a miniature electrical connector having housing members which effects selective engagement and disengagement between male and female contact members while the housing members are in slidable engagement. The female electrical contact has legs of diverse resonant frequencies to insure physical engagement between the contacts when the electrical connector is closed and subject to a high vibratory environment.

BRIEF DESCRIPTION OF THE DRAWINGS A more complete appreciation of the invention and many of the attendant advantages thereof will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. I is an exploded, perspective view, partly in section, of the overall miniature connector of the invention;

FIG. 2 is a schematic view of a prior art female electrical contact; and

FIGS. 3 and 4 are schematic views of alternative female electrical contacts of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing wherein like reference characters designate identical or corresponding parts throughout the several views and more particularly to FIG. 1 thereof wherein the electrical connector of the present invention is shown as having an upper housing II. and a corresponding lower housing l2 formed, in part, of

insulating material

13 and 14 respectively. Housing l1 includes an electrical male contact member l5 fixedly secured therein which may be formed of any desired conducting material such as, for example, nickel, copper, gold flash or the like. Extending from an upper portion 16 of the male contact member is a narrow elongate electrical male contact 17, which may be a knife blade or the like, adapted to engage a female electrical con tact 18 disposed in lower housing 12. Electrical male contact member I5 may be secured in the insulating material 13 by any conventional means, such as, for example, frictionally or the like. Connected to upper portion 16 of the male contact member is a terminal 19 adapted to receive a lead 20 for connecting the electrical male contact member to one side of an electrical circuit.

Female electrical contact 18 is seated in a concavity 2! having a narrow slot portion 22 extending therefrom. Parallel to slot portion 22, and on opposite sides thereof, are elongate

narrow slots

23a and 23b adapted, as will hereinafter be explained, to slidably guide upper housing II on lower housing 12. A terminal 24 is connected to female electrical contact 18 to permit connection to a lead 25 thereby placing the female electrical contact into the other side of an electrical circuit. Projecting from upper housing ll are guides 26a and 26b, adapted to be seated into slots 23a and 2312, respectively, of lower housing I2, and of such dimension as to allow axial movement of upper housing ll on lower housing 12 in the directions as shown by arrowhead 27.

In operation, the seating of guides 26a and 26b in

slots

23a and 23b, respectively, allows upper housing 11 to conformingly seat atop lower housing 12 and also permits axial movement of the upper housing relative to the lower housing while the housings are in contiguous relationship. With the guide near one extremity 28a and 28b of the slots, electrical male contact 17 rests in narrow slot portion 22. When, however, the guides are moved from extremity 28a, 28b to the opposite extremity 29a, 2%, housing 11 slidably moves atop housing 12 and thereby moving male contact 17 axially in narrow slot portion 22 into engagement with female electrical contact 18. Thus, it is readily apparent that axial movement of upper housing 11, relative to lower housing 12, effects selective engagement or disengagement of the electrical connector and consequent interruption or closure of the external electric circuit. Furthermore, male contact 17 and female contact 18, whether in engagement or disengagement with each other, are protected from outside influences, such as dirt or the like, by upper and lower housing II and I2 which physically rest atop each other.

As shown in FIG. 2, heretofore employed female electrical contacts have been formed of a U-shaped end portion 30 integral with an inwardly projecting portion 31 having out wardly extending end portions 32a and 32b for receiving electrical male contact I7. When the connector is in its closed position, male contact 17 physically engages

points

33a and 33b, the juncture of the inwardly projecting portion and the receiving ends. As hereinbefore explained, however, when a connector employing this type female contact is subjected to a high vibratory environment, the female contact 18 vibrates to cause momentary disengagement with the male connector. This results from the fact that junction points 33a and 33b, normally in engagement with the thin electrical male contact 17, resonate with equal resonant frequencies.

Referring now to FIG. 3 the female electrical contact 18 of the present invention is shown as consisting of a terminal portion 24, U-shaped end portion 34, inwardly projecting portion 35, outwardly extending

receiving ends

36a, 36b, and contact points 37a and 371; formed at the juncture of the inwardly projecting portion and the receiving ends which engage the electrical male contact 17 when the connector is in a closed position. Female electrical contact 18 is so constructed that one leg thereof is of a lesser thickness than the other leg. Thus, it is readily apparent that the leg including junction point 37a is of a different mass than the leg including junction point 37b due to the difference in thickness of the two legs.

Thus, when the connector is in a closed position, that is, when thin electrical male contact 17 is between and in engagement with

junction points

37a, 37b and the connector is subject to a high vibratory environment, the legs of the female electrical contact no longer vibrate with the same resonant frequency. This unequal resonant frequency of vibration of the legs of the female electrical contact allows either one of the junction points, 37a or 371;, to remain in engagement with the electrical male contact 17. Thus, during the vibrational excitation at least one junction point, 37a or 37b, stays in engagement with the electrical male contact 17, thereby, preventing arcing or any other undesirable characteristic which may result from an unwanted interruption of the external circuit.

It has been found, however, that in the manufacture of the female electrical contact 18 and, more particularly, during the flashing process thereof, it is required to spread apart the legs of the female contact clement. Thus, it is required, during manufacture, to spread apart

junction points

37a and 37b of the female electrical contact. The spreading apart of the junction points introduces memories" into the female electrical contact which may cause the junction points, 37a and 37b, to open when the connector is subject to a high vibratory environment despite the different masses of the contact legs.

To avoid this phenomenon a female electrical contact is shown in FIG. 4 is provided and is formed of a terminal portion 24, a U-shaped end portion 34 connected to inwardly projecting portion 35 which, in turn, projects outward at receiving

ends

36a and 36b. As hereinabove explained, electrical male contact 17 slidably moves into the receiving

ends

36a and 36b to engage junction points 370 and 37b. It is to be noted, however, that the inwardly projecting portion 35 is formed of two sides, 38a and 38b, of different lengths and, therefore,

offset junction points

37a and 37b spatially displaced relative to each other. By so providing different lengths of the inwardly projecting portion, the masses of the two legs of the female electrical contact are different and, therefore, this difference in mass insures that at least one junction point, 370 or 37b, of the female electrical contact will remain in engagement with the electrical male contact 17 when the connector is subject to a high vibratory environment. Furthermore, by so constructing the female electrical contact it is readily apparent that a larger space between the

junction points

37a and 37b is provided. This increased space between the junction points, while not effecting the distance of the junction points to the electrical male contact 17, eliminates the requirement for spreading the junctionportions apart during manufacture and, therefore, prevents introduction of memory" into the female electrical contact.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings such as, for example, including a fastening member (not shown) on the upper housing 11 and lower housing 12 to insure that the guides 26a and 261) do not slide in the

slots

23a and 23b during vibration. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

lclaim:

1. An electrical connector comprising! a pair of housing members of a substantially identical overall configuration;

one of said housing members having a substantially centrally disposed elongate male electrical contact and a pair ofguide members projectin therefrom; the other of said housing mem ers having a plurality ofconcavities formed therein, one of said concavities having an integral elongate slot portion and a pair of said concavities being of an elongate configuration disposed on opposite sides of said elongate slot portion in a parallel relationship therewith for individual reception of said guide members; and

a U-shaped female electrical contact disposed in said one of said concavities and having portions thereon for engaging said elongate male electrical contact when said pair of guide members are seated at one extremity of said pair of concavities and to be disengaged therefrom when said guide members are seated at the other extremity of said pair of concavities.

2. An electrical connector according to claim 1 wherein, said one of said housing members covers said plurality ofconcavities of said other of said housing members when said guide members are seated at said one extremity or at said other extremity of said pair of concavities.

3. An electrical connector according to claim 1 wherein, said elongate male electrical contact is longitudinally movable within said elongate slot portion for alternatively engaging and disengaging said U-shaped female electrical contact.

4. A female electrical contact for receiving a male electrical contact comprising an inwardly projected U-shaped member having leg portions of diverse resonant frequencies.

5. A female electrical contact according to claim 4 wherein one leg portion is ofa mass different from that of the other leg portion.

6. A female electrical contact according to claim 5 wherein said legs portions are ofdiverse thicknesses.

7. A female electrical contact according to claim 5 wherein said leg portions are of diverse lengths.

8. A female electrical contact for receiving a male electrical contact comprising:

a U-shaped member;

a terminal portion attached to said U-shaped member for connecting an electrical lead to said female contact; and

a pair of leg portions of different masses integrally formed with said U-shaped member wherein each of said leg portions includes an inwardly projecting portion and an outwardly projecting portion.