US3223962A

US3223962A - Plug receiving contact

Info

Publication number: US3223962A
Application number: US313414A
Authority: US
Inventors: Kemper M Hammell
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1963-09-30
Filing date: 1963-09-30
Publication date: 1965-12-14
Anticipated expiration: 1982-12-14

Description

Dec. 14, 1965 K. M. HAMMELL 3,223,962

PLUG RECEIVING CONTACT Original Filed 001;. 8, 1956 INVENTOR.

lflemper M. Hqmme United States Patent Office 3,223,962 PLUG REKJEIVING CONTACT IIernper M. Hammell, Harrisburg, Pa, assignor to AMP Incorporated, Harrisburg, Pa. Continuation of application Ser. No. 614,551, Oct. 8, 1956. This application Sept. 30, 1963, Ser. No. 313,414 3 Ciairns. (Cl. 339-256) This application is a continuation of my copending application, Serial No. 614,551, filed October 8, 1956, and now abandoned. This invention relates to disconnect electrical terminations of the so-called friction type and more particularly to a pin receptacle connector.

In many applications it is desirable to terminate wire leads from an apparatus in a group of pins or posts which are adapted to be frictionally engaged in a female receptacle connected to suitable cables for connection to the rest of the electrical circuit. Typical applications for connections of this type are in the refrigerating and air conditioning fields where portions of the equipment are hermetically sealed and connection must be made to a series of pins or posts extending through the shell of the hermetically sealed portion.

Heretofore various pin receptacle connectors have been suggested and have been partially successful for certain limited application. However under severe operating conditions, both temperature and humidity, it has been found that all connections heretofore known have failed to give the desired low resistance contact over a long period of time necessitating either frequent cleaning or replacing of the connections. According to the present invention I have discovered that by placing special wrap-around pin contacting surfaces on a pair of parallel bridge-like flexible spans that a greatly increased contact area of low unit contact pressure can be obtained resulting in a superior long life connection.

It is an object of the present invention to provide a pin receptacle having substantially more than a line or point contact with the pin inserted therein. It is another object of the present invention to provide a pin receptacle that has low unit contact pressure over a large area of contact. It is another object of the present invention to provide a low contact resistance pin receptacle that will maintain its low resistance contact throughout a long period of time under adverse atmospheric and temperature conditions. It is another object of the present invention to provide a pin receptacle of improved low contact resistance that may be made of cheaper, more readily available materials than heretofore known. It is a still further object of the present invention to provide a pin receptacle with wrap-around contact surfaces to provide substantial areas of contact with a pin inserted therein. These and other further objects will be in part apparent and in part pointed out as the specification proceeds.

In the drawings:

FIGURE 1 is a side elevation of the pin recepticle of the present invention;

FIGURE 2 is a top plan view of the pin receptacle of the present invention;

FIGURE 3 is an end view of the pin receptacle of FIGURE 2;

FIGURE 4 is a fragmentary view of the contact portion of the pin receptacle of FIGURES 1 through 3 priorto Patented Dec. 14, 1965 insertion of a pin showing the relative curvature of the pin and contact surfaces thereof;

FIGURE 5 is a view similar to FIGURE 4 showing the pin inserted in the pin receptacle.

Referring now to FIGURE 1 the pin receptacle 20 comprises generally the receptacle portion 22, a barrel portion 24 and an insulation support portion 26. The barrel portion 24 and insulation support portion 26 are of conventional design and crimped according to a wellknown crimp and are not described in detail herein for the sake of brevity. The receptacle portion 22 comprises generally two

thin gauge spans

28 and 30 which are supported at the top by the

tabs

32 and 34 and at the bottom by the U-shaped root sections 36 and 33 respectively of the connector. Each of the

spans

28 and 30 has an inwardly concave contact surface 40 at approximately the center thereof and a pair of slots 42 cut therein as will be described in detail herein.

As may be seen in FIGURES 1 through 3 the

locking ears

32 and 34 are formed integrally with the

spans

28 and 30 and then bent substantially at right angles thereto to engage the opposite span. FIGUURES 1 and 3 show at the end of the ears 32 and 34 a locking tab 44 which extends upwardly to engage the side of the opposite span. The

locking ears

32 and 34 as they are bent around to engage the opposite span seat in a cut-out 46 which cooperates with the tabs 44 to provide the desired support of the upper edges of spans 28 and 31 In addition to giving the superior performance as will be described herein in actual operation the foregoing constructure together with the root sections 36 and 38 allow an independent control of the width of both the top and bottom of the receptacle portion 22 in the manufacture thereof which results in increased flexibility of the product and better quality control in the manufacturing thereof.

The

spans

28 and 30 are formed of a relatively thin gauge stock so that they are somewhat flexible and act like bridge spans joined at the end but free to flex in the middle. The contact areas 40 have a radius somewhat greater than the radius of the pin to which they are to be connected and are spaced apart somewhat less than the diameter of the pin to which the receptacle is to be joined. This may be seen in FIGURES 4 and 5. Also the upper edge of the contact surfaces 40 are s-waged or otherwise beveled outwardly at 41 in somewhat the manner of a bell mouth to facilitate the entrance of the pin therein.

FIGURE 4 shows receptacle 20 in its normal position with a pin 48 about to enter into the receptacle portion thereof. As may be clearly seen the pin 48 is slightly larger in diameter than the spacing between the contact surfaces 40 of the receptacle 20. However it will be noticed that the radius of curvature of the contact surfaces themselves are greater than the radius of curvature of pin 48. In FIGURE 5 the pin 48 has been inserted into the receptacle 20 and as may be readily seen this has sprung the

spans

28 and 30 somewhat apart and in so doing has caused them to wrap around the pin 48 to provide a relatively large area of contact between the contact areas 40 and the pin 48. This flexing has taken place between the suspension points at the top and bottom of the ends of the

spans

28 and 30 as previously described. The flexing or bending actually takes place in the contact surface portions 40 insuring a complete and intimate wraparound contact over a substantially larger area of the pin than heretofore possible.

Without the bending of the surfaces 40 contact is obtained along a line such as 43 in FIGURE 4. With the flexing taking place in surfaces 40 a wide area of contact is obtained as between

lines

45 and 47 in FIGURE 5.

Since the

spans

28 and 30 are of relatively thin gauge metal the pressure necessary to produce this flexing is relatively slight and the actual contact pressure is of a low unit magnitude although the total pressure holding the receptacle on the pin may be considerably greater than that encountered with other types of receptacles having single line or point contacts but very high unit pressures. This not only facilitates the connection and disconnection of the receptacle and pin but also provides a greatly increased life and a much lower average contact resistance between the receptacle and the pin.

With the high unit pressure line or point contact type of receptacle occasionally the initial contact obtained between the receptacle and pin may be greater than that obtained with the receptacle of the present invention. However it has been conclusively found that such a connection in the presence of high temperature and humidity very soon loses its low initial resistance and in a short period of time will have developed a relatively high contact resistance that progressively gets worse until the joint or connection fails. On the contrary with my broad area, low unit contact pressure connection while the initial contact resistance may be slightly greater than with other types of high unit pressure contacts the resistance remains substantially constant and does not increase materially under the influence of high temperature and humidity.

For instance with the former type line contact, high unit pressure terminal, a terminal temperature of as high as 380 degrees Fahrenheit is not uncommon in an ambient temperature of approximately 200 degrees Fahrenheit. With my broad area, low unit contact pressure terminal the maximum temperature observed has been only 250 degrees Fahrenheit with an average somewhere in the neighborhood of 230 degrees Fahrenheit. Furthermore, the voltage loss in the connection has been measured at more than 300 millivolts at 5 amperes load for the former, while with my connection the average drop has been millivolts with a maximum of between and 50 millivolts. It is obvious from this data that the minimum service life of a connection according to the present invention would be many times that of a connection of the line or point, high unit contact pressure type.

This low temperature of my receptacle has a further advantage in that it is possible to utilize cheaper materials since the temperature requirements are not as severe. For instance, in the example given above it is possible to use with my receptacle a Phosphor bronze material which has very satisfactory creep stability at the 250 degree Fahrenheit maximum temperature encountered, however, with the line contact type of terminal a beryllium copper which is three to four times as expensive is necessary if creep stability is to be maintained at the elevated temperature of 380 degrees Fahrenheit encountered with that type of connection.

Referring again to FIGURES 1 through 5 it will be noted that the

spans

28 and 30 are substantially parallel from top to bottom thereof and that in actual application such as FIGURE 5 they are still substantially parallel from top to bottom. This, it has been found, is a very important feature of my pin receptacle in that if the contact areas 40 are not maintained substantially parallel when the pin 48 is inserted therein it will cause a spreading out of the contact areas such that only a line or ring contact is established at the lower or upper end so that only a very small area of contact will be obtained at either the upper or lower end of the contact surfaces 40. As described herein, by adjusting the

locking ears

32 and 34 and the spans 36 and 38 during the manufacture of the receptacle the

spans

28 and 30 will be maintained very closely parallel. In actual operation I have found that if the distance between the tops of the

spans

28 and 30 is not over twoto three-thousandths greater and not over four-thousandths less than the distance at the bottom that uniform low resistance contact throughout the entire length of the contact area 40 will be obtained.

Referring now to FIGURE 1 a cut-out will be seen at the bottom of the receptacle 20. This is provided to ensure the resilient bridge span action of the

spans

28 and 30. The slots 42 help in the accurate forming of contact surfaces 40 and under certain conditions help to reduce the frictional drag where ease of application is of paramount consideration.

While there is given above certain specific examples of this invention and its application in practical use, it should be understood that this is not intended to be exhaustive or to be limiting of the invention. On the contrary, these illustrations and explanations herein are given in order to acquaint others skilled in the arts with this invention and the principles thereof and a suitable manner of its application in practical use, so that others skilled in the art may be enabled to modify the invention and to adapt and apply it in numerous forms each as may be best suited to the requirement of a particular use.

I claim:

1. An electrical connector for detachably securing together electrical conductors by frictional contact between a pin contact and a pin receptacle comprising in combination a barrel portion for pressure forming about the end of an electrical conductor, a pin receptacle portion including a pair of parallel span members integrally joined together at opposite ends of one side, a pair of locking ears mounted on the ends of said spans adjacent the unjoined sides thereof, a cooperating locking slot adapted to receive therein said locking ears to securely hold the other side of said spans in proper spaced relation, an inwardly concave contact surface formed in said spans adjacent the mid-point thereof, a narrow slot in said spans on each side of said contact surfaces, said spans being spaced apart a distance such that said contact surfaces are spaced less than the diameter of the pin to be received therein and said surfaces having a radius of curvature greater than said pins.

2. Al one-piece resilient sheet metal receptacle for slidably receiving an elongated contact member in detachable frictional engagement to effect an electrical connection comprising a pair of opposed elongated contact surfaces spatially disposed less than the corresponding dimension of the contact member and defining a socket for axial reception of the contact member, side wall portions extending laterally from opposed sides of each of said surfaces at both ends of said socket, a pair of spaced bights and ear means extending from and rigidily anchoring the end portions of said sidewall portions, said bights being on opposite sides of said socket at one end thereof, said ear means extending from one side and interlocking with a sidewall portion on the other side of the socket at the other end thereof, said bights and ear means being substantially in transverse alignment with the lateral extent of said sidewall portions, so that said sidewall portions and intermediate portions of said contact surfaces are constrained to flex as resilient beams fixed at both ends.

3. A one-piece resilient sheet metal receptacle for slidably receiving an elongated contact member in detachable friction engagement to effect an electrical connection comprising a pair of opposed elongated contact surfaces spatially disposed less than the corresponding dimension of the contact member and defining a socket for axial reception of the contact member, sidewall portions extending laterally from opposed sides of each of said surfaces at both ends of said socket, bight means extending from and rigidly anchoring the end portions of said sidewall portions at one end of said socket, ear means extending from and rigidly anchoring the end portions of said sidewall portions at the other end of said socket,

both ends.

5 6 said ear means extending from one side and interlocking 2,502,385 3/ 1950 Ludwig 339-208 with a sidewall portion on the other side of the socket, 2,519,584 8/1950 Ludwig 339208 said bight means and ear means being substantially in 2,600,190 6/1952 Batcheller 339256 transverse alignment with the lateral extent of the asso- 2,663,457 12/ 1953 Shaffer. ciated ones of said sidewall portions so that said sidewall 5 2,711,524 6/ 1955 Beaver 339-256 portions and intermediate portions of said contact sur- 2,720,636 10/1955 McKinley 339-192 faces are constrained to flex as resilient beams fixed at 2,728,060 12/1955 Doeg 339-192 FOREIGN PATENTS References Cited by the Examiner 10 408,301 4/ 1934 Great Britain. 604,880 7/ 1948 Great.Britain. UNITED STATES PATENTS 640,432 7/1950 Great Britain.

4/ 1902 Betts. 1/1332 g 3 ALBERT H. KAMPE, Primary Examiner.

ar or 10/1938 Baker 5 JOSEPH D. SEERS, PATRICK A. CLIFFOgD, 12/1941 Clayton. mmmers-

Claims

1. AN ELECTRICAL CONNECTOR FOR DETACHABLY SECURING TOGETHER ELECTRICAL CONDUCTORS BY FRICTIONAL CONTACT BETWEEN A PIN CONTACT AND A PIN RECEPTACLE COMPRISING IN COMBINATION A BARREL PORTION FOR PRESSURE FORMING ABOUT THE END OF AN ELECTRICAL CONDUCTOR, A PIN RECEPTACLE PORTION INCLUDING A PAIR OF PARALLEL SPAN MEMBERS INTEGRALLY JOINED TOGETHER AT OPPOSITE ENDS OF ONE SIDE, A PAIR OF LOCKING EARS MOUNTED ON THE ENDS OF SAID SPANS ADJACENT THE UNJOINED SIDES THEREOF, A COOPERATING LOCKING SLOT ADAPTED TO RECEIVE THEREIN SAID LOCKING EARS TO SECURELY HOLD THE OTHER SIDE OF SAID SPANS IN PROPER SPACED RELATION, AN INWARDLY CONCAVE CONTACT SURFACE FORMED IN SAID SPANS ADJACENTS THE MID-POINT THEREOF, A NARROW SLOT IN SAID SPANS ON EACH SIDE OF SAID CONTACT SURFACESE, SAID SPANS BEING SPACED APART A DISTANCE SUCH THAT SAID CONTACT SURFACES ARE SPACED LESS THAN THE DIAMETER OF THE PIN TO BE RECEIVED THEREIN AND SAID SURFACES HAVING A RADIUS OF CURVATURE GREATER THAN SAID PINS.