US3497866A - Electrical connector - Google Patents

Description

Feb. 24, 1970 R, A, PATTON, 1R 3,497,866

ELECTRICAL CONNECTOR Filed Jan. 25, 1967 4 Sheets-Sheet 1 F/'GJ BY WyWQLlD/M Feb. 24, 1970 R. A. PATTON, JR 3,497,866

ELECTRICAL CONNECTOR Filed Jan. 25, 1967 4 Sheets-Sheet 2 INVENTOR.' Eby/4. fcfr;

BY W MHM,

Feb. 24, 1970 R. A. PATTON, JR 3,497,866

ELECTRICAL CONNECTOR Filed Jan. 25, 1967 4 sheets-sheet :s

BY MWMM Feb. 24, 1910 I R, A, PATTON, JR I 3,497,866

ELECTRICAL CONNECTOR Filed Jan. 25. 1967 4 sheets-sheet 4 Ffa/4A la INVENTOR.

Pag A. PaZzon5J'r;

BY Mwuz United States Patent O 3,497,866 ELECTRICAL CONNECTOR Roy A. Patton, Jr., Grabill, Ind., assigner to Hood, Gust, Irish & Lundy, Fort Wayne, Ind. Filed Jan. 25, 1967, Ser. No. 611,599 Int. Cl. H011' 13/50 U.S. Cl. 339-176 14 Claims ABSTRACT OF THE DISCLOSURE An electrical connector comprising male and female coupling elements, each having contact members disposed in longitudinally extending passageways formed therein. Each of the contact members in the female coupling element is resiliently engaged in a longitudinallyoverlapping relation with an associated contact member in the male coupling element.

The present invention relates to an electrical connector, and more particularly to a multiple circuit connector which is ideally suited for microelectronics equipment applications.

Quite recently, great efforts have been expended in miniaturizing and microminiaturizing circuit components such as resistors, capacitors, transistors and diodes. To date, the effort, which has been highly successful, has produced monolithic integrated circuits and thin film circuits which achieve volume reductions, over conventional components, as great as 1,000 times While, at the same time, achieving increases in reliability. However, efforts to miniaturize connectors which may be used to interconnect such miniaturized circuitry have not been so successful. It has been found, for instance, that conventional connectors cannot merely be made smaller to obtain a reliable miniaturized connector. To the contrary, completely new concepts, such as are embodied in the present invention, are required. Specifically, the connector of the present invention is so proportioned and arranged that mating contact members are securely urged together in an overlapping relationship so that a significantly minimized contact resistance is obtained, especially when the contact members are heated by current ow therethrough or by external sources such as increases in ambient tem peratures or exposure to altitudes in excess of 50,000 feet. In fact, the contact resistance between mating contact members of the present invention is actually further reduced when the contact members are heated, because expansion of the metal contacts cause decreased terminal resistance in lieu of the normal resistance increase experienced with other design concepts.

Another feature of the connector of the present invention is that each contact member is designed so it can be repeatedly removed and replaced without deterioration or damage to a degree well below normally accepted wear factors. Also, each contact member is substantially embedded in the insulating material of the body of the connector to prevent damage thereof. Although the connector of the present invention is ideally suited as a miniaturized connector, the concepts embodied in the connector are equally applicable for larger connectors.

Each contact member consumes essentially one-half of a cylindrical passageway and mates 'with its mating contact which consumes essentially the opposite half of an extension of the same passageway. No size increase in the structure is required as is true with other concepts such as a pin and sleeve, for example, wherein the pin represents the male contact and the larger sleeve represents the female contact.

It is an object of the present invention, therefore, to

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provide an improved electrical connector of unique construction which is ideally suited for reliably connecting a large number of circuits in a relatively small space. This permits making connections in a space approximating the diameter of a cable with which the connector is to be used.

Another object is to provide such a connector which is extremely small in size yet reliable, durable and efficient in use and relatively inexpensive to manufacture.

A further object is to provide such a connector having mating contact members so proportioned and arranged that an increase in temperature of said contact members reduces the contact resistance therebetween, this being most important for low signal level applications such as aerospace, telemetry systems and the like.

Still another object is to provide such a connector having contact members which are easily removed and replaced without the necessity of expensive complex pin insertion and/ or removal tools.

Still a further object is to provide such a connector having contact members which are substantially embedded in insulating material and, therefore, protected from damage by either intentional or accidental mishandling.

The above-mentioned and other features and objects of the present invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. l is a side view of the connector of the present invention showing the male and female coupling elements in mating relationship;

FIG. 2 is an end view of the male coupling element taken from the right-hand side of FIG. l;

FIG. 3 is `a sectional view taken from FIG. 2 generally along the line 3-3 and showing the male and female coupling elements in a mating relationship and showing contact members in the male coupling element in contact with the respective contact members in the female coupling element; Y

FIG. 4 is a partially sectioned, side view of the connector of the present invention showing the male coupling element disconnected from the female coupling element;

FIG. 5 is an end view of the female coupling element taken from the right-hand side of said element in FIG. 4;

FIG. 6 is an end view of the male coupling element taken from the 1eft-hand side of said element as shown in FIG. 4;

FIG. 7 is a perspective view of a contact member which is carried by the female coupling element;

FIG. 8 is a fragmentary sectional view showing the insertion of a contact member in its passageway in the male coupling element;

FIG. 9 is a fragmentary sectional view of the male coupling element showing a contact member already locked in place in its passageway;

FIG. 10 is a perspective view of one type of contact member which is disposed in the male coupling element;

FIG. 10a is a plan view of a stamping from which one contact member is formed;

FIG. 11 is a perspective view of another type of contact member which is disposed in the male coupling element;

FIG. 12 is a fragmentary sectional view showing the use of a tool to remove a contact member from the male coupling element;

FIG. 13 is a fragmentary cross-sectional view taken from FIG. 9 generally along the line 13-13 and illustrating the position of contact members in the male coupling element;

FIGS. 14, 15, 16, 14a, 15a and 16a are side views, re-

spectively, of the three different contact members used in the connectors of the preceding figures, these latter figures being drawn substantially to scale; and

FIG. 17 is a fragmentary rear View of one of the connector assemblies showing the positioning of a contacting member in a passageway.

The connector of the present invention, indicated generally by reference number 10, comprises a male coupling element 12 an-d a female coupling element 14. The male coupling element 12 and female coupling element 14 are shown in a mating relationship in FIGS. l and 3 and disconnected in FIG. 4.

The male coupling element 12 comprises an essentially cylindrically-shaped body of insulating plastic material having a front end 16 and a rear end 18 (FIG. 4), and a plurality of axially extending passageways 20y which communicate with the ends 16 and 18. The passageways 2t) are arranged in two coaxial, circular sets, and are circumferentially and equally spaced-apart in each set. In the illustrative embodiment, the outer circular set of passageways 20 (FIGS. 3, 4 and 6) contain contact members 22 and the inner circular set of passageways 20 contain contact members 24. The passageways 20 are cylindrically shaped; however, it is within the scope of this invention for the passageways 20 to be square, rectangular or any other suitable shape.

As seen in FIG. 3, each passageway 20 is formed with a radial protrusion 26 having a radial abutment surface 26a which serves to hold a contact member 22, 24 in the passageway.

The male elements 12 is provided with a plurality of different diameter, cylindrical step-portions on the front end 16 and the back end 18. In FIG. 4, it can be seen that the opposite ends 16 and 18 are subtsantially identically shaped. These step-portions are coaxial and are indicated bythe reference numbers 28, 30, 32 and 34, respectively.

Step- portions 28 and 34 are of substantially equal diameter and step- portions 30 and 32 have diameters substantially equal to each other. The passageways 20 of the inner circular set extend axially opposite as grooves 36 (FIGS. 4 and 6) and 38 (FIGS. 2 and 3) in the outer peripheral surfaces of the step- portions 28 and 34. Likewise, the passageways 20 of the outer circular set extend axially opposite as grooves 40 (FIGS. 4 and 6) and 42 (FIGS. 2 and 3) in the outer peripheral surfaces of the stepportions 30 and 32. The grooves 36 and 38, as extensions of the respective passageways 20, are provided for receiving the contacting and terminal ends, respectively, of the contact members 24. The grooves 40 and 42 are provided for receiving the contacting and terminal ends, respectively, of the contact members 22.

In FIG. 4, it can be seen that the male coupling element 12 is provided with an axially extending cylindrical key 44 having an axially extending flat surface 46 for rotationally positioning the male coupling element 12 with respect tothe female coupling element 14.

The female coupling element 14 is also an essentially cylindrically-shaped body having a front end 48 and a rear end 50, and a plurality of cylindrical, axially extending passageways 52 which communicate with the ends 48 and 50, respectively. The passageways 52 are arranged in a pair of circular sets circumferentially equally spaced-apart and are arranged to be axially aligned with the two circular sets of passageways 20 in the male element 12 and the when the male element 12 and the female element 14 are connected. Each of the passageways S2 in the outer circular set of passageways receives a contact member S4 which is releasably engageable with an associated contact member 22 in the male element 12, when the male element 12 is connected to the female element 14. Similarly, each of the passageways 52 in the inner circular set of the female element 14 receives a contact member 54 which releasably engages an associated contact member 24 in the male element 12, when the male clement 12 is connected to the female element 14.

In FIGS. 3 and 4, it can be seen that the female element 14 has different diameter cylindrical step-portions at the front end 48 and at the rear end 50. However, the stepportions, indicated by reference numbers 56 and 58, at the front end 48 are socket-like and are arranged to receive, respectively, the plug-like step- portions 28 and 30 of the male element 12. The step-portions, indicated by the reference numbers 60 and 62, are substantially similar to, and are provided for the same reasons as, the stepportions 32 and 34 at the rear end 18 of the male coupling element 12. The inner circular set of cylindrical passageways 52 are oppositely extended to form axially extending grooves 64 (FIGS. 4 and 5) and 66 (FIG. 3), respcctively, in the peripheral surfaces of the step-portions 56 and 60. Likewise, the outer circular set of cylindrical passageways 52 are extended oppositely to form axially extending grooves 68 (FIGS. 3, 4 and 5) 70 (FIG. 3) in the peripheral surfaces of the step- portions 58 and 62. All of the grooves 36, 38, 40, 42, 64, 66, 68, 70 in both the male and female elements are semi-cylindrical in shape. The grooves 64 and 68, respectively, in step-portions 56 and 58 are provided for receiving the contacting end of the contact members 54, and the grooves 66 and 7 0 in the external step- portions 60 and 62, respectively, are provided for receiving the terminal end of the Contact members 54.

The passageways 52 are also provided with radial abutment surfaces 74 on the protrusions 72 (FIGS. 3 and 4) which serve to hold the contact members 54 in the passageways.

From the foregoing discussion, it can be seen that the end 48 of the female coupling element 14 is essentially a socket for receiving the complementary shaped end 16 of the male coupling element 12. Each of the contact members 22 and 24 received in the male coupling element 12 is releasably engageable with an associated contact member 54 when the male coupling element is connected to the female coupling element. The outer sets of passageways 20 and 52 in the male and female elements 12 and 14, respectively, are equal in number and in circumferential spacing.

The step- portions 32 and 34 at the rear end 18 of the male coupling element 12 and the step-portions 60` and 62 at the rear end 50 of the female coupling element 14 are provided to separate lead wires which are attached to the contact members in the male and female coupling elements. Since the terminal portions of the contact members are separated by the step-portions, such as the step portions 60 and 62, all of the well known wire-joining concepts, such as soldering, crimping, wrapping and welding, are facilitated. In addition, the advanced wire-joining concepts, such as electron beam and laser welding techniques, are easily accomplished because of the concentric circles of terminals which are positioned on the step-portions. For instance, wires can be welded to the inner circle of terminals as the coupling elements are rotated through an electron welding beam or beams and then wires can be similarly welded to the outer circle of terminals as the coupling elements are rotated through an electron welding beam or beams. Of course, it is to be understood that a lead wire is to be positioned and held in physical contact with each terminal end of the contact member during the welding operation.

The insulating material of the body of the male coupling element 12 and female coupling element 14 may be a thermal plastic, thermal setting or a solvent soluble type plastic. Specifically, polyester, TFE iluorocarbon, polyethylene, vinyl, Bakelite, phenolics and the like are satisfactory plastic materials. Whatever material is used, the bodies of the male coupling element 12 and female coupling element 14 should be relatively rigid and should not deform under localized pressure or deform as does soft rubber. When compared to the spring construction of the metallic contact members 22, 24 .and 54, the

body material of the male and female coupling elements 12 and 14 may be regarded as rigid and non-exble.

An attractive feature of the connector of the present invention is the self-centering capability provided by the mating step-portions and the circular arrangement of the `Contact members. When the male and female coupling elements 12 and 14 are mated, the key 44 is received in an internal, axially extending, complementary shaped bore 76 to further center the male coupling element in the female coupling element as well as to position radially and rotationally the male coupling element with respect to the female coupling element. As seen in FIGS. and 6, the bore 76 has a at surface 78 corresponding to and intimately mating with the flat surface 46 of key 44. As clearly shown in FIG. 4, the male and female steps 28, 30 and 56, 58, respectively, have intermediate, mating, cylindrical step portions which further insure coaxial alignment, increase insulating path length between circles of contacts, and the like.

Referring to FIGS. 7, 8, 9, 10, a, 14, 15 and 16, the structure of the contact members and in particular contact members 22 and the means whereby the contact members are inserted into and held in passageways will be discussed. Contact members 22, which may be fabricated from conductive metals having some degree of springiness, such as bronze, brass, copper, aluminum, gold, silver, platinum, or alloys thereof, such as beryllium copper, are formed, in this embodiment, by a number of methods such as casting or a coining or stamping operation in which the first step is to stamp from a at, thin sheet of metal an elongated, flat blank having substantially the form shown in FIG. 10a. This blank has a somewhat rectangular terminal end 84, a tapered length 80, another length portion 82 of uniform width, and a distal length portion or tab 86 of uniform, but smaller, width. The precise dimensions will become apparent from the description that follows. The portions 80 and 84, as an integral length and uniform extensions of each other, are formed to the illustrated shape of FIG. 10,' such that in cross-section they are U-shaped. The portion 84 forms into a larger U-shape and hereinafter is referred to as a terminal end or portion 84. The smaller elongated U-shaped portion `80 hereinafter is referred to as a shank or shank portion 80.

At 88 where the portion I82 narrows into and joins portion 86, the blank is bent into a reflex curve such that the portion 86, now called a tab or tab portion 86, extends rearwardly in underlying parallelism with respect to the portion 82 (FIGS. 10 and 14). This latter portion 82 hereafter is termed a contact or contact portion 82. The resulting shape is shown in FIG. l0. The bend 88 is smoothly curved such that the tab 86 normally is spaced slightly from the contact portion 82. The metal is sufficiently resilient and the bend 88 flexible as a hinge that the tab 86 may be swung into engagement with the contact 82 but will return to its illustrated position when released.

By providing the bend at 88 along a line at right angles to the longitudinal axis of the blank of FIG. 10a, the tab 86 will underlie symmetrically the Contact portion 82 as indicated by the dashed line shape 89. The reason for the difference in width between the tab 86 and the contact portion 82 will become apparent from the description later following.

As viewed in FIGS. 8, 9, l() and 14, the contact portion 82 is slightly bowed inwardly longitudinally and provides an exposed, elongated surface 90 facing outwardly hereafter termed a contact surface 90. The portions 82, 88, 86 conjointly are hereinafter in the claims referred to as a detent portion.

The terminal end 84 of each of the contact members 22 is formed with the U-shape for receiving a lead wire therein. Portions 82 and 86 together function as a spring, biasing the contact surface 90 against the contact surface of its associated contact member 54 (FIG. 3).

In FIG. 14, the contact member 22 is shown in side elevation and is drawn substantially to scale. As there shown, the shank l is elongated and has a general longitudinal axis 91 which, for purposes of later reference in the claims, is termed a length axis. Using this straight length axis 91 as a reference, it will be noted that the contact portion 82 angles away therefrom. The tip portion 93 of the end 88, now termed a cam end 88, is slightly inclined as shown to provide a calm surface, with the sharper radius portion being therebelow. The contact portion 82 is slightly bowed toward the tab portion 86 as shown. The tab portion 86 is also slightly bowed toward the contact portion l82, a part of tab portion l86 being substantially parallel to contact portion 82 as shown and the remaining part thereof angling away so as to form roughly a V-shape therewith.

The shank 80 in its thickness dimension, this dimension lying in the plane of the drawing, progressively increases from end 95 thereof adjacent to contact portion 82 in a direction toward the terminal end 84. This `thickness is made such that as the shank 80 is partially inserted into its opening 20 as previously explained (FIGS. 8 and 9), the top longitudinal edges 97 provided by the channel shape of the shank 80 engage the wall of the passageway 20 in the upper portions thereof such that progressive insertion of the shank into the passageway 20` results in the shank 80 as well as the terminal 84 being forced downwardly into the bottom portion of the passageway 20 and the groove 42 as illustrated in FIG. 17. Thus, the shank 80 lits snugly in its passageway 20. Should it develop that the distance between the terminal edges 94 (FIGS. 10 and 14) and the tip 98 are farther apart than the distance between abutment surface 26a (FIG. 8) and surface 96, the contact member 22 will nevertheless firmly lock into the respective passageway 20. This may be explained as follows. As the contact member 22 is being inserted into the passageway 20 (FIG. 8), and it is inserted far enough for the tip 98 (FIG. 14) to snap over the abutment surface 26a and become engaged therewith, as shown in FIG. 9, before this occurs the upper edges 97 of the shank 80 engage the wall of the passageway 20, providing a frictional lock therebetween. This frictional lock inhibits further penetration or insertion of the contact member 16 into the passageway 20 while the engagement of the tip 89 with abutment surface 26a prevents withdrawal of the contact member. Therefore, if it should develop in the fabrication of the coupling element 12 that the length thereof is made slightly shorter than that represented in FIG. 9, the contact member 22 will nevertheless fit tightly and properly into its passageway 20 and will be held against longitudinal movement. This particular construction relaxes substantially the requirements for holding close fabrication tolerances with respect to the overall length of the coupling element 12 as well as with respect to the contact member 22 itself, since the tapered, channelshaped shank 80 can be forced into the passageway 20 until tip 89 locks over the abutment surface 26a (FIG. 8). Progressive insertion of the shank 80 into passageway 20, resulting in more forceful frictional engagement therebetween, merely results in squeezing the top edges 97 of shank 80 inwardly toward each other. The springiness of the shank 80 reacts radially so as to engage more positively the wall of the respective passageway 20. The passageways 20 may also be provided with a taper whereby progressive insertion of the member 22 is further frictionally resisted.

Assuming that the parts are precisely fabricated, as shown in FIG. 9, the tip 89 will engage the abutment surface 26a, and the edges 94 will engage the radial surface 96 on the end of the coupling element 12. This is differently illustrated in FIG. 17. The side flanges on the terminal 84 extend beyond the opening of the passageway 20 (FIG. 17) such that the contact member 22 cannot be inserted into the passageway 20 farther than the abutting engagement will permit. Thus, the Contact member 22 is firmly locked against longitudinal movement in its respective passageway 20.

By reason of the angle formed between the shank 80 and the contact 82 (FIG. 14), when the contact member 22 is fully inserted into its passageway 20, as shown in FIG. 9, the cam end or portion 88 will be yieldably urged into engagement with the bottom of the groove 40 at the end thereof. The tab 86 will be compressed and bowed slightly upwardly from this groove bottom, and the contact portion 82 itself will be bowed slightly downwardly toward the bottom. This is clearly shown in FIGS. 4 and 9. The groove 40 holds the detent portion 82, 88, 86 against lateral movement. The contact member 22 is thereby rmly secured and positioned in its passageway 20, but the detent portion 82, 88, 86 is yieldable or flexible radially. In this connection, it should be understood that the curved portion of the cam end 88 is relatively rigid radially of the body 12; however, the contact portion 82 is movable toward and engageable with the tab 86, this latter part also being movable toward the bottom of the groove 40 (FIG. 9).

In FIG. 8, it can be seen that a Contact member 22 is installed in the body 12 by longitudinal insertion into the passageway 20 in the direction of the arrow 99. After insertion into its passageway 20 as shown in FIG. 9, the contact member 22 is held against longitudinal movement toward the front end 16 of the male element 12 by abutment of the radial edges 94 of terminal end 84 against the radial surface 96 extending outwardly from the step portion 32, and against longitudinal movement toward the rear end 18 by engagement of the tip 98 of tab 86 with the abutment surface 26a (FIGS. 8 and 9). The Contact member 22 is thereby locked against longitudinal movement in its passageway 20 between the surface 96 and the surface 26a of the protrusion 26.

The Contact members 24 (see FIG. 11), which are received in the inner set of passageways 20 in the male element 12, are similar to the Contact members 22 and are also formed of blanks shaped as shown in FIG. a. The length of the shank 102 (FIGS. 11 and 16) plus contact portion 104, however, is decidedly longer than the length of shank 80 plus contact 82 for Contact 22 (FIGS. l0 and 16). This greater length is necessary because the passageways of the inner circle receiving contact members 24 are considerably longer than the outer circle of passageways 20 receiving the Contact members 22. This relationship is clearly shown in FIG. 3.

Each member 24 is provided with a U-shaped terminal end 106, a U-shaped shank 102 like shank 80, a contact portion 104 bent slightly at 110, and a tab 108 bent rearwardly in underlying, substantially parallel relationship with respect to the distal portion of contact portion 104. The tab 108 is narrower than contact 104 and is connected thereto by the smooth bend 112 like bend 88 (FIGS. 10 and 16). Aside from the shallow bend 110, and the greater length, the Contact member 24 is substantially identical to the contact member 22. When contact member 24 is installed, the bend 110 is attened and thereby resiliently forcefully urges contact portion 104 into engagement with the walls of its passageway 20. Further, as shown in FIG. 3, when contact member 24 is installed, the tip or cam portion 114 of tab 108 engages the respective abutment surface 26a, and the terminal end edges 116 engage radial surface 118 extending outwardly from step-portion 34 (FIGS. 2 and 3), thereby locking member 24 against longitudinal movement.

The contact member shown in FIG. 16, which is drawn substantially to scale, has the shank 102 provided with slightly more curvature than the shank 80 shown in FIG. 14; however, it extends in the direction of the straight line axis indicated by numeral 119, this axis also being called the length axis in the claims appended hereto. This length axis 119 extends substantially parallel to the general length or direction of the shank 102. It will be noted that the cam end or portion 112 therefore lies to one side of the length axis 119. The shank 102 is tapered in thickness the same as shank of FIG. 14 and furthermore fits into its passageway 20 the same. Once installed, the shank 102 as well as the terminal portion 106 are firmly seated into the bottom of the respective passageway 20 and groove 38 (FIG. 2), thereby locking frictionally the shank 102 in place. This results in springing the cam end 112 downwardly into engagement with the bottom of the respective groove 36 (FIGS. 4 and 6), the tab portion 108 being slightly bowed upwardly from the bottom of the groove 36 and the contact portion 110 being bowed oppositely and being spaced slightly from tab portion 108. In all other respects, the Contact member 24 fits into its passageway 20 as does the contact member 22 (FIG. 14) in its passageway 20.

The structure of the contact members 54, received in passageways 52 of the female element 14, is illustrated in FIGS. 7 and 15. This member 54 is also formed of an elongated blank like that shown in FIG, 10a and described hereinabove. In other respects, it is shaped substantially identically to member 22 (FIG. l0) with the exception that the tab 126 overlies the Contact portion 122 (FIG. 7) instead of being bent under as in the case of tab 86 of FIG. l0. Otherwise, the member 54 includes U-shaped terminal end 124, U-shaped shank 120, contact portion 122 and tab 126. The latter is spaced slightly from and is substantially parallel to contact portion 122 and is joined thereto by the smooth bend or cam end 128. When the member 54 is installed, tip 114 engages abutment surface 74 (FIG. 3) in its passageway 54 and the terminal end edges 130 engage the radial surface 132, 134 (as the case may be) extending outwardly from the step-portions 60, 62 (FIG. 4), respectively. Each member 54 is thereby locked against longitudinal movement in its passageway 52.

In FIG. 15, the Contact member 54 is shown in side elevation substantially to scale. In this view, the Shank is shown tapered in thickness the same as the shanks of the contact members 22 and 24 described hereinabove, and as extending substantially straight (with slight curvature) so as to define a length axis 135. This axis forms a slight angle to the longitudinal extent of the terminal portion 124 as shown.

The Contact portion 122 is slightly bowed toward the tab 126 and the latter likewise is bowed toward the contact portion 122.

When the contact member 54 is installed into its passageway, the shank 120 frictionally engages the wall thereof as previously explained, and the cam end 128 is forced into engagement with the bottom of its groove 64, 68. Thus, the tab portion 126 is bowed upwardly or away from slightly the bottom of the groove 64, 68, while the contact portion 122 is bowed slightly toward the groove bottom, there being provided a slight spacing between the two parts 122 and 126 as shown more clearly in FIG. 4.

Reference to FIGS. 14, 15 and 16 Will reveal that all of the contact members are preformed such that the tips of the tab portions 86, 126 and 108 are angled away from the respective shank portions a distance substantially greater than the diameter of the passageways 20 and 52. Thus, when the contact members are inserted into the respective passageways, the tab portions 86 will be sprung toward the respective contact portions. This then provides the shapes in the detent portions (82, 88, 86), (108, 104, 112), (122, 126, 128), as shown in FIGS. 3, 4 and 9.

It has been found that beryllium copper is a suitable material for fabricating the contact members 22, 24 and 54. Beryllium copper is known to be dimensionally stable after forming and suitable heat treating so that it is capable of returning to Van established memory line after it is deformed.

The tab portion 86, 108, 126 of each of the contact members 22, 24 and 54, respectively, is narrower and smaller in cross-section than the respective contact portion 82, 104, 122 because the tab portion 86, 108, 126 must fit into the bottom of the respective passageway and groove containing the contact members as shown in FIG. 13.

In FIG. 13, it can be seen that each tab portion 86 is fitted into the bottom portion of the respective groove 40 and therefore must be smaller in width than the contact portion 82 of the contact member 22 inasmuch as the width of the contact portion 82 is approximately equal to the diameter of the passageway 20. The tabs 108 and 126 of contact members 24 and 54, respectively, are similarly disposed in their respective grooves 36 and 64, 68. It has been found that the contacting surfaces 90 and 104 (FIGS. 10 and 1l) of the contact members 22 and 24, respectively, should project radially outwardly from the surfaces of the step- portions 30, 28, respectively, by a distance equal to approximately of the diameter of the passageways (FIG. 13). Similarly, the contacting surface 146 (FIG. 7) of the contact members 54 should extend radially inwardly from the surfaces of the female step-portions 56 and 58 by a distance equal to approximately 10% of the diameter of the passageways 52.

The contact members 22, 24 and 54 are proportioned so that the contacting ends thereof are permitted to deflect radially. Specifically, contacting surfaces 90 and 104 (FIGS. 10 and 11) of contact members 22 and 24 deect radially inwardly and contacting surfaces 146 (FIG. 7) of contact members 54 deflect radially outwardly when coupling elements 12 and 14 are mated.

As clearly seen in FIG. 3, when male element 12 is mated to female element 14, the contacting end of each contact member 22, 24 and 54 is so compressed that the tab portion 86, 108, 126 thereof conductively engages the respective Contact portion 82, 104, 122 thereof. Thus, the effective cross-sectional area of contact members 22, 24 and 54 at the contacting ends thereof is increased, for current-carrying capacity, by the cross-sectional area of tab portions 86, 108, 126. Since the contacting ends of contact members 22, 24 and 54 -are radially deflected more deeply into the respective grooves 36, 40, 64, 68, 22, 24, 54 when the male element 12 is mated to the female element 14, the distal or leading portions of the surfaces 90, 148, 146 (FIGS. 7, 10 and 11) of the contacting ends of the contact members serve as camming surfaces for deflecting the engaging contact member radially deeper into its groove 36, 40, 64, 68. For instance, as seen in FIGS. 3 and 4, the contacting surface 90 of a contact member 22 exerts a force urging the contacting surface 146 of the engaged contact member 54 radially outwardly while the contacting surface 146 of its associated member 54 exerts a force urging the contacting surface 90 of the contact member 22 radially inwardly. It can be seen, therefore, that the force exerted between the contacting surfaces 148, 146 and 90, 146 of engaged contact members, when the male and female elements 12 and 14 are mated, is determined by the resiliency properties of the material from which the contact members are fabricated, the curvature of the contact portions, the curvature of the reflex bends 88, 112, 128, and the difference in diameters of mating step-portions of the male and female members 12 and 14, respectively. By varying any one of the above-mentioned characteristics, the force of engagement between each mated pair of contact members as well as the force required to connect and disconnect the male and female coupling elements 12 and 14 can be varied. The connector of the present invention can be designed with a locking action between mating contact members which is sufficient, in many applications, to provide a positive locking force for holding the coupling elements 12 and 14 in mated relationship even during periods of shock and vibration, thus eliminating the requirement for the additional locking capability of peripheral hardware. This locking action is obtained by the force of er1- gagement exerted between each engaged pair of contact CII members in the connector. The force of engagement eX- erted between contacting surfaces of engaged contact members also provides an efficient wiping and/or cleaning action for the contacting surfaces when the male coupling element 12 is inserted into the female coupling element 14, thereby minimizing, and in some cases virtually eliminating, the usual pitting and corrosion processes which lead to excessive resistance between mating contact members, as well as corona discharge and other common processes of deterioration which exist when mating contact members are not engaged with suficient force. Of course, the electrical resistance between mating contact members is reduced by increasing the force and area of contact between the contacting surfaces of said contact members.

When the male element 12 is inserted into the female element 14, all of the contact members are deflected at the contact ends thereof substantially in unison and by substantially equal forces. In a preferred embodiment of the present invention, the deflecting force exerted on each contact member is substantially equal to the reaction force exerted by each contact member in returning to its original curvature. It is therefore apparent that such `arrangement provides a more stable connector which will perform satisfactorily when subjected to shock and vibration throughout the entire electrical frequency spectrum.

The connector 10 of the present invention can be easily manufactured because of the greater tolerances permitted by the step-diameter construction with mating contact members varranged in concentric circles. That is, the above-described construction of the connector 10 permits Awidely varying tolerances in the positioning of individual contact members without affecting adversely the total connector assembly because of build-up or accumulation of tolerances. Thus, significant cost reductions are obtainable, because associated equipment and systems utilizing the connector 10 are not required to have precisely machined connector alignment frames. Also, a cost reduction is achieved because standard precision molding equipment only is required for fabricating the body of the male and female coupling elements 12 and 14, respectively, and because the contact members 22, 24 and 54 can be fabricated with typical and easily obtainable metal-forming tolerances.

As clearly seen in FIG. 3, mating contact members of the connector 10 have considerable longitudinal overlap. The longitudinal overlap of mating contact members permits liberal longitudinal tolerances in the mating of the male coupling element 12 to the female coupling element 14.

When the male and fem- ale elements 12 and 14 respectively are disconnected as shown in FIG. 4, the contacting ends of the various contact members 22, 24 and S4 assume normally the positions there shown, these positions being further illustrated in FIG. 13. Upon inserting the male member 12 into the female member 14, the key 44 is first engaged with the socket 76, such that the flat surface 46 coincides with the companion surface 78 (FIG. 5) in the female member. This axially aligns all of the contact members S4 in the female member 14 with the respective contact members 22 and 24 in the male member 12. Further insertion of the male member 12 into the female member 14 results in initial contact of the reflex-bend or cam ends 88 and 112 (of the male contact members 22 and 24) with the reflex-bends or cam portions 128 of the respective female contact members 54. These cam portions are so dimensioned that further insertion of the male member 12 into the female member 14 will result in the male and female contactingr members camming or sliding longitudinally over each other, the contact portions 90 and 104 of the male members 22 and 24, respectively, thereby deecting radially inwardly and the companion contact portions 122 of the female contact members 54 deflecting radially outwardly.

As again more clearly shown in FIG. 4, the radial di- 11 mensions (i.e., radially of the connector body) of the cam portions 88, 112 and 128 of the various contact members 22, 24 and 54 are greater than the dimensions measured rearwardly thereof across the respective contact portion 82 and tab 86, for example. Note in FIG. 4 that the tab 861 between its ends is more closely positioned to the contact portion 82 than are these same two parts adjacent to the cam 88. The same is true for the other contact members 24 and 54.

Being so shaped, the contact surfaces 90, 104 and 146 of contact members 22, 24 and 54 are longitudinally undulated, the undulation of the male members matching and being complementary to the undulations of the female contact members.

Therefore, when the male member 12 is fully inserted into female member 14, the cam of the male contact members will be positioned in the narrower or valley portions of the female contact members, and vice versa, thereby longitudinally locking the male and female contacts together. Again noting the relationship of the mating contacts in FIG. 3, the cam portions are lightly compressed between the bottoms of the respective grooves and the end portion of the contact member with which it is engaged. Thus, the mating portions of the contact members are forcefully resiliently engaged, over extended surface areas, with each other. As a consequence of the undulations or curved configuration of the mating portions of the contact members, any forces tending to separate longitudinally these Contact members serve to increase the contact pressure therebetween. Thus, the contact members themselves function to lock the male member 12 and female member 14 together.

In operation, contact resistance between mated contact members of a connector, such as connector described above, may result in a temperature rise of the contact members. The structure of connector 10 is such that a temperature rise will cause mated contact members to expand dimensionally to be forced together more tightly, thereby producing more intimate engagement between contacting surfaces resulting in a reduction of the resistance between and consequently temperature of the contact members. Further, the curvature of tab portion 86, 108, 126 and contact portion 82, 104, 122 of each contact member is such that when a contact member is heated, the longitudinal curvature is increased to cause each contacting member to exert a greater radial force against its mating contact member. This increase in curvature, which actually is a decrease in radius of curvature, is caused by the contacting surface 90, 148, 146 of the contact member (FIGS. l0, 1l and 7) increasing in length as compared to the tab portion 86, 108, 126 which is bent back under (or over, as the case may be) the contact portion `82, 104, 122.

Recapitulating, the connector 10 is so constructed that an increase in temperature of the contact members, even if caused by contact resistance, will cause mated contact members to become more intimately engaged and to thereby exert more contacting force over a greater contacting area, resulting in a decrease of the resistance between said contact members.

The contact members, when mated, with connected circuits energized, have a tendency to become more securely engaged due to the ever present forces between male and female contact members that result from contact members being constantly distorted away from their established memory lines, which in unison are attempting to return thereto. Each pair of contacts, male and female, having become mated together beyond the highest cam point thereof and approaching but not arriving at the lowest cam point, thus have a natural tendency, when subjected to shock or vibration, to become more intimately engaged one with the other, thus drawing the male and female assemblies into a more secure physical position and electrically into lowered resistance contact. Also, when the contact members are produced from precious metals or metals plated with precious metals, such precious metals, especially gold, have a tendency to work into microscopically sized balls when movement of the metal parts results from vibration or shock. The contact portions of these microscopically balled surfaces become semiwelded or fused together when connected circuits are energized. Thus, the greater the current and more intense and prolonged the vibration the more efficient and stable the mating of the contact members becomes.

The basic design of the contact members also results in temperature coecient factors between all contact members which are equal during mated periods, thus providing stabilized and uniform terminal resistance factors throughout the assemblies at all points within a temperature range of 60 C. to +250 C. (as examples only) which is a proven must for aerospace and many other applications. In metallurgical terms, beryllium copper, e.g., is very unstable and erratic when distorted away from its established memory line. However, on the contrary, it is most stable and constant in every respect when attempting to return to its established memory line, a feature which is constantly in existence herein during mated periods.

In the illustrative embodiment of the present invention, there is an O-ring seal disposed coaxially in the front end `48 adjacent to the periphery of the female coupling element 14 and a similar, mating O-ring seal 152 disposed coaxially in the front end 16 of the male coupling element 12, as shown. The O- ring seals 150 and 152 may be fabricated from any well known rubber-like material normally used for sealing electrical connectors or similar equipment.

The structure of the contact members 22, 24 and 52 is such that they can be easily removed from their respective passageways 20 as clearly shown in FIG. l2. In the illustrative example of FIG. 12, a simple tool, indicated generally by reference number 154, is used to lift the contact portion 82 and tab -86 of a contact member 22 above the protrusion 26 and out of engagement with surface 26a, thereby permitting the contact member 22 to be pulled from the passageway 20 in the direction of arrow 156. Preferably, the tool 154 has a cylindrical shank provided with a attened end 158 large enough to lift tab 86 out of engagement with surface 26a. Alternatively, a sleeve 160 may be slidably disposed over the tool 154 as shown in FIG. l2 and is provided with a flattened tongue 162 having a cam surface 164 on the end adapted to slide under tab 86 to lift it out of engagement with surface 26a.

The connector 10 of the present invention is not susceptible to the normally experienced damage caused by mishandling or abusing the connector, because the Contact members 22, 24 and 54 are substantially embedded in the body of the male and female coupling portions 12 and 14, respectively. The contacting ends of the contact members are raised only slightly above the respective step-portions in which they are embedded. Thus, even when the male and female coupling elements 12 and 14 are disconnected, the contact members are not as susceptible to abuse as are contact members of other well known connector designs. It is to be pointed out that this is a very important feature, because the contact members of microminiaturized connectors are, by necessity, very small, frail and diflicult to assemble, disassemble or otherwise to work with even by highly skilled and trained personnal without causing unintentional damage.

Although the above description and the illustrative ernbodiment are directed toward a cylindically-shaped connector, it is obvious that the scope of the present in vention includes structures other than cylindrical.

The passageways in both the male and female units 10 and 12 may be hermetically sealed by providing the contact elements 22, 24 and 54 intermediate the ends 13 thereof with rubber sealing rings molded thereabout which peripherally engage the respective passageways. These rings are slightly larger than the diameter of the passageways, and provide a iuid-tight wall preventing leakage of gas through the passageways.

The drawings illustrate a working embodiment of thiS invention having the following listed dimensions, these dimensions being given by way of example only and not by limitation. It will appear obvious to persons skilled in the art that these dimensions may be altered without departing from the spirit and scope of the invention:

Inches Diameter of body 10, (OD.) .6562 Diameter of passageways 52 .060 Axial length of stub 58 .0957 Axial length of stub 56 .095 Depth of socket 76 .1580 Radial depth of shoulder 74 .015 Axial length of protrusion 72 .046 Distance between shoulder 74 and surface 134 .200 Length of body .4202 Length of step 62 .0937 Length of step 60 .0937 Passageway 20 diameter .060 Radial depth of shoulder 26a .015

Axial dimension between shoulder 26a and surface 96 .200 Diameter of key 44 .1568 Diameter of key 44 measured from the iiat 46 .125 Length of key 44 .1562 Length of step 28 .0937 Length of step 30 .0937

FIGS. 14a, 15a and 16a, also drawn to scale, have dimensional information in inches and degrees applied thereto for the working embodiment mentioned hereinabove.

While there have been described above the principles of this invention in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.

What is claimed is:

1. For use in an electrical connector, an elongated metallic contact member having length, width and thickness dimensions, said contact member including terminal and detent portions on the opposite ends thereof, an elongated shank portion interconnecting said terminal and detent portions, said detent portion including an elongated contact portion and an elongated tab portion disposed adjacent to each other and extending in longitudnal juxtaposition, adjacent ends of said contact and tab portions coinciding with one end of said contact member, a curved cam portion resiliently joining said adjacent ends, said contact and tab portions being resiliently flexible and movable toward and away from each other, the opposite end of said tab portion being juxtaposed with respect to said contact portion and being free to move toward and away therefrom, said contact portion having an elongated contacting surface on the side thereof opposite said tab portion, said terminal portion being channel-shaped and being a longitudinal extension of said shank portion, said terminal portion having two side flanges extending transversely beyond the shank portion to thereby serve as an abutment, said shank portion being channel-shaped longitudinally, said shank portion being rigid in comparison with said detent portion, the channel shape of said terminal portion being an extension of the channel shape of said shank portion with the exception of said side flanges which project laterally therebeyond, said side flanges having abutment edges lying in a plane intersecting the length axis of said shank portion at right angles, said edges being next adjacent to said shank portion, and said contact portion being wider than said tab portion, the thickness of the shank portion progressively increasing in a direction from said contact portion to said terminal portion such that the thickness of said contact member increases in said direction from said contact portion to said terminal portion, the sides of the channel-shaped shank portion extending in a direction parallel to the thickness dimension, said contact member in a region substantially midway between the opposite ends thereof being bent with gradual curvature to position said cam portion to one side of an extension of the length axis of said shank portion, said gradual curvature being defined about an axis which intersects at right angles a plane including the length axis of said shank portion, said last-mentioned plane being parallel to the thickness dimension of said contact member.

2. The contact member of claim 1 in which the bottom of said shank portion is curved and determines the bottom of the contact member, said tab portion being disposed beneath said contact portion.

3. The contact member of claim 1 in which the bottom of said shank portion is curved and determines the bottom of the contact member, said tab portion being disposed above said contact portion.

4. The contact member of claim 1 in which said contact portion is generally straight but slightly longitudinally curved oppositely to said gradual curvature.

5. The contact member of claim 3 in which said contact portion is generally straight but slightly curved oppositely to said gradual curvature.

6. The contact member of claim 5 in which said shank portion has said gradual curvature which extends from a. point immediately adjacent to said terminal portion to a. point adjacent to said contact portion, said gradual curvature being in a direction such as to position the bottom of said shank portion outermost, said terminal portion being straight and elongated, said shank and terminal portions being joined by a portion curved oppositely to that of said gradual curvature.

7. The contact member of claim 1 wherein said tab portion has a length portion adjacent to said cam portion which extends substantially parallel to said contact portion and a remaining length portion extending at an acute angle away from said contact portion thereby forming a general V-shape between said contact portion and said tab portion, and said cam portion having a curvature formed about an axis normal to said last-mentioned plane.

8. For use in an electrical connector, an elongated metallic contact member having length, width and thickness dimensions, said contact member including terminal and detent portions on the opposite ends thereof, anelongated shank portion interconnecting said terminal and detent portions, said detent portion including an elongated contact portion and an elongated tab portion disposed adjacent to each oth-er and extending in longitudinal juxtaposition, adjacent ends of said contact and tab portions coinciding with one end of said contact member, a curved cam portion resiliently joining said adjacent ends, said contact and tab portions being resiliently exible and movable toward and away from each other, the opposite end of said tab portion being juxtaposed with respect to said contact portion and being free to move toward and away therefrom, said contact portion having an elongated contacting surface on the side thereof opposite said tab portion; in combination with the contact member as defined hereinbefore, a rigid body of insulating material, said body having opposite ends and at least one substantially straight passageway extending therethrough between said ends, said ends each having a step-portion extending therefrom, each step-portion having a surface extending substantially parallel to said passageway, each surface further extending from about the cross-sectional midportion of said passageway, each surface having a groove which is a uniform longitudinal extension of said passageway, said passageway receiving said contact member for sliding movement longitudinally but holding said contact member against lateral movement, said detent portion being received and held against lateral movement by the groove of one step-portion, said terminal portion being received and held against lateral movement by the groove of the other step-portion, locking means for holding said Contact member against longitudinal movement in its passageway; there being a plurality of said passageways parallel to each other and arranged in a cylindrical pattern, the surfaces on said step-portions being cylindrical and coaxial with respect to said cylindrical pattern, said step-portions having a plurality of said grooves therein which are extensions of said passageways, respectively, there being a plurality of said contact members, respectively, received by said passageways and grooves; the contacting surfaces of said detent portions projecting radially above the surface of said one step-portion, and said locking means including engaging parts on said body and said contact members for preventing longitudinal movement of said contact members in one direction, abutment means on said body engageable by said opposite ends of said tab portions for preventing longitudinal movement of said contact members in the opposite direction; and said engaging parts on said body and contact members including means urging and positioning the terminal and shank portions onto the bottoms of the respective passageways and grooves, the terminal portions, respectively, fitting into the grooves of said other step-portion.

9. The combination of claim 8 in which one of said engaging parts includes said shank portion of each contact member being of a shape which progressively increases in thickness in a direction from said contact portion to said terminal portion, the shank portion in the region adjacent to said terminal portion engaging the wall of the respective passageway on the side opposite the bottom thereof, thereby forcing said shank portion against said bottom, said cam portion being operatively engaged with the bottom of the respective groove, the contact portions in the regions between the respective cam and shank portions being spaced from the groove and passageway -bottoms thereby providing for flexing movement toward and away from said bottoms.

10. For use in an electrical connector, an elongated metallic contact member having length, width and thickness dimensions, said contact member including terminal and detent portions on the opposite ends thereof, an elongated shank portion interconnecting said terminal and detent portions, said detent portion including an elongated contact portion and an elongated tab portion disposed adjacent to each other and extending in longitudinal juxtaposition, adjacent ends of said contact and tab portions coinciding with one end of said contact member, a curved cam portion resiliently joining said adjacent ends, said contact and tab portions being resiliently flexible and movable toward and away from each other, the opposite end of said tab portion being juxtaposed with respect to said contact portion and being free to move toward and away therefrom, `said contact portion having an elongated contacting surface on the side thereof opposite said tab portion; in combination with the contact member as defined hereinbefore, a rigid body of insulating material, said body having opposite ends and at least one substantially straight passageway extending therethrough between said ends, said ends each having a step-portion extending therefrom, each stepportion having a surface extending substantially parallel to said passageway, each surface further extending from about the cross-sectional midportion of said passageway, each surface having a groove which is a uniform longitudinal extension of said passageway, said passageway receiving said contact member for sliding movement longitudinally but holding said contact member against lateral movement, said detent portion being received and held against lateral movement by the groove of one stepportion, said terminal portion being received and held against lateral movement by the groove of the other step-portion, locking means for holding said contact member against longitudinal movement in its passageway; there being a plurality of said passageways parallel to each other and arranged in a cylindrical pattern, the surfaces on said step-'portions being cylindrical and coaxial with respect to said cylindrical pattern, 'said stepportions having a plurality of said grooves therein which are extensions of said passageways, respectively, there being a plurality of said contact members, respectively, received by said passageways and grooves; the contacting surfaces of said detent portions projecting radially above the surface of said one step-portion, and said locking means including engaging parts on said body and said Contact members for preventing longitudinal movement of said contact members in one direction, abutment means on said body engageable by said opposite ends of said tab portions for preventing longitudinal movement of said contact members in the opposite direction; and said abutment means including within each passageway a radially extending abutment surface engageable by the opposite end of the respective tab to prevent longitudinal movement of the contact member in said opposite direction, each contact portion being liexible and bowed downwardly toward the respective groove bottom, each said cam portion Ibeing relatively rigid radially and operatively engaged with the bottom of the respective groove, each contact portion being spaced from its groove bottom, each tab portion being disposed between its contact portion and its groove bottom, said passageways being circular in cross-section and said grooves being semi-cylindrical extensions thereof; said shank and terminal portions being channel-shaped longitudinally and U-shaped in cross-section, the shank-portion progressively increasing in thickness, as measured radially of said Ibody, from said contact portion to said terminal portion, the shank portion in its thickest portion being engageable with the respective passageway wall to thereby force the bottom curved part of the shank portion as well as the terminal portion against the bottom of the respective passageway and groove, the curvatures of the shank and terminal portions conforming to the curvatures of the respective passageways and grooves, said shank portions being firmly fitted into the respective passageways, said detent portions being resilient and preformed to urge the cam portions thereof into operative engagement with the bottoms of the respective grooves as aforesaid.

11. The combination of claim 10 in which each said U-shaped terminal portion has anges extending radially of said body and engageable with an end portion of the latter to prevent movement of the terminal portion into the passageway.

12. The combination of claim 11 in which said one step-portion extends inwardly of said body to form a cylindrical socket.

13. The combination of claim 11 in which said one step-portion projects beyond the adjacent end of said body to provide a plug portion.

14. The combination of claim 10 wherein said contact mmeber in a region substantially midway between the opposite ends thereof is bent with a gradual curvature to position said cam portion to one side of an extension of the length axis of said shank portions, said gradual curvature being defined about an axis which intersects at right angles a plane including a length axis of said shank portion, said shank portion having said gradual curvature which extends from a point immediately adjacent to said terminal portion to a point adjacent to said contact portion, said gradual curvature being in a direction which positions the bottom of the shank portion outermost, said terminal portion being straight and elongated, said shank and terminal portions being joined 17 1S by a portion curved oppositely to that of said gradual 3,118,713 1/ 1964 Ellis 339-176 X curvature- 3,196,380 7/1965 Krehbiel -4 339-217 X References Cited RICHARD E. MOORE, Primary Examiner UN TED STATES PATENTS I D U.S. C1. XR.

2,938,190 5/1960 Krehbiel 339-217 X 339-182, 217

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