US3253253A - Connector - Google Patents

Description

United States Patent 3,253,253 CONNECTOR Arvin L. Langharn, Northridge, Calif., assignor to The Deutsch Company, Electronic Components Division, Banning, Calif., a corporation of California Continuation of abandoned application Ser. No. 239,642, Nov. 23, 1962. This application Feb. 19, 1965, Ser.

7 Claims. Cl. 339-255 and connected to individual cables are plugged into the sockets, and the cables are thereby joined electrically and conductively by the connector.

In circuits wherein high performance pin-and-socket connectors are used, it is frequently important that resistance at the junction be kept to a minimum. It is also important that the socket have a long life, often on the order of 500 or more connecting and disconnecting cycles. Furthermore, because continuity tests are made at these sockets by the insertion of test probes, usually with high side loads exerted by the tester, the socket must be inherently rugged. As is usual in situations wherein a number of requirements of this type are imposed, few, if any, of them are fully met. Instead, the resulting design is a compromise, meeting each as fully as possible.

One of the severest design limitations is imposed by the requirement to resist test probes. Ideally, a socket would be designed only to resist the relatively small side and wearing forces exerted by a connector pin as it is inserted straight into the socket, and not specifically to resist side forces exerted by a probe used as a lever. Never theless, because this latter will occur in practice, it is necessary to design the socket 'With a view toward inherently limiting or eliminating, if possible, the damage which may be done when someone checks the continuity with a probe and exerts strong forces on the socket in so doing. Resistance to probe damage calls for a strongly resisting spring, or for very hard material in conventional sockets. These, however, are inconsistent with the limitation that contact pressure should be uniform and as low as possible in order to minimize wear and extend the life of the socket. As to minimizing resistance at the junction, the most suitable material do not necessarily fulfill the requirements of either of the above design criteria. Thus, the optimum solutions to the various individual limitations are contrary to each other, and customarily the conventional designs have adopted a middle value in which each requirement was not optimally met.

In the past, two conventional types of electrical connections have been in most common use. One may be characterized as the cantilever beam type, and the other may be characterized as the snap-ring type. In the cantilever beam type, the socket is formed with one or more projecting spring fingers which contact the pin when it is inserted into the socket. The pin will spread the spring fingers slightly, and the springback forces grip the pin to form a secure electrical contact. In the snap-ring type of contact, the socket is slotted and a split ring is fitted around the socket with the end of the split ring projecting into the socket to press against the pin when it is inserted into the socket.

Patented May 24, 1966 Both of these types present the problems enumerated above with respect to design limitations. For example, the cantilever type requires that the spring fingers be fabricated from material which possesses high tensile strength, which ordinarily is characterized by low conductivity, poor machinability and poor ductility. However, if such materials are not used, then the spring fingers will readily be sprung out of shape by a probe, and they will not thereafter exert the necessary springback forces to make a good contact with the pin. The snap-ring type of socket is inherently weak due to the small cross-sectional area of the contact in the slotted region and, therefore, is even more prone to test probe damage.

The present invention provides an electrical socket contact which goes farther toward meeting the enumerated design requirements and in overcoming the above limitations than previously known devices, and which accomplishes this with a simple, but radically different construction. It resists probe damage, greatly improves the durability of such a socket, and inherently minimizes resistance at the junction.

These objectives are accomplished by separating the functions of springback forces needed to contact the pin, and of resisting probe damage. In previous devices, these two functions have been accomplished by only a single part, the spring fingers of the cantilever type, for example, thereby requiring the aforesaid unfavorable compromises. Such compromises are not required in this invention.

A socket according to this invention includes an electrically conductive body member having an internal sidewall which defines a bore having an axis. The bore receives a pin to make a connection between cables electrically connected to the pin and body. A slot opens into the bore through the sidewall. A floating contactor memberis placed in the slot, and is laterally movable therein.

A first abutment surface on the contactor member and a second abutment surface on the body member are so disposed and arranged as to contact each other to limit the extent of movement of the contactor member laterally outward from the axis.

Spring means is disposed between the members to force the contactor member toward the lateral axis thereby to press against the pin or the probe. The members forma recess for these spring means which receives the spring without permanent deformation thereof when the abut ment surfaces contact each other. The spring means is thereby secure against permanent deformation, so that the floating contactor will always be biased toward the axis with a proper force. Because the floating contactor member which is actually contacted by the pin or probe is not relied on for springing forces, it can be made of material best suited to make an effective, long wearing, damage-resistant contact. The functions of flexibility, strength to resist damage, and low contact resistance have thereby been separated, and optimum performance can It is no longer necessary to are always farther apart from each other than the abutment surfaces.

The above and other features of this invention will be fully appreciated from the following detailed description and the accompanying drawings, in which:

FIGURE 1 is an axial cross-section of the presently preferred embodiment of the invention;

FIGURE 2 is a cross-section taken at line 22 of FIG- URE 1;

FIGURE 3 is a fragmentary cross-section of an alternate embodiment of the invention;

FIGURE 4 is an end view of a portion of FIGURE 1;

FIGURE 5 is a side elevation of a portion of FIGURE 1; and

FIGURE 6 is a fragmentary cross-section showing still another embodiment of the invention.

The presently preferred embodiment of a socket 10 according to the invention is shown in FIGURE 1. This device includes a body member 11 having a first section 12 and a second section 13. The first section is shown in detail in FIGURE 5. The second section is a simple tube with an internal diameter equal to the outer diame'ter of a portion of first section 12.

The :body member includes an internal sidewall 14 defining a bore 15 which has an axis 16. A chamfer 17 at the open end of the bore facilitates the insertion of a pin 18 thereto.

Both the body member and the pin are adapted, by means not shown, to be attached to respective cables so that inserting the pin into the socket as shown in FIG- URE 1 electrically and structurally joins the cables. Body member and pin are both customarily fastened or cast into insulating material.

As best shown in FIGURE 2, second section 13 fits snugly over first section 12 and is attached thereto, such as by crimping it into groove 19 on the body. Before this assembly has been completed, a cut 20 (FIGURE 5) is made across the first section to a depth greater than the wall thickness. This forms a slot 21 which opens onto the bore through the sidewall. The second section encompasses and closes the slot from the outside.

A floating contactor member 25 is placed within the slot and is backed up by a spring means 26. The contactor member and spring means are placed inside the out before the second section is placed over the first section, thereby enabling the device readily to be assembled.

The floating contactor member is shown in full detail in FIGURES 1, 2 and 4. It is adapted to move laterally toward .and away from the central axis, entering the bore from the slot. It is adapted to be retracted by the pin, as" best shown in FIGURES 1 and 2, or by a probe which might be inserted into the bore.

The floating contactor member has a bearing surface 27 facing the central axis and a pair of ramp surfaces 28, 29. The bearing surface is adapted to press against the pin. Ramp surface 29 facilitates the insertion of the pin or probe into the bore. Two ramp surfaces are provided so that the floating contactor member is reversible in assembly.

A pair of shoulders 30, 31 are formed in the first section at opposite sides of the bore, which are overhung by the floating contactor member and which prevent it from falling out of the slot into the bore. Side surfaces 32, 33 are formed on the contactor member to provide for a wider area of contact with shoulders 30, 31 and still clear the inside wall of second section 13.

Spring means 26 preferably comprises a flat leaf spring bent to a uniform radius. A suitable spring may be a piece of 0.004" stock of Iberyllium copper, Berylco No. 25, 1/4 hard, gold-plated, which is 0.195" long when flat. It may conveniently be bent to a radius of 0.115". A suitable width is 0.040". For a size 16 socket, this appears to exert an optimum force on the floating contactor.

As can best be seen in FIGURE 2, the leaf spring is disposed between the body member and the contactor member on the opposite side of the contactor member from the axis. A recess 35 is formed between the two members by first recess boundary surface 36 on the inside of section 13 and by second recess boundary surface 37 on the top of the contactor member as shown in FIGURE 2.

First abutment surfaces 38 are formed on the contactor member which, in the preferred embodiment, comprises the outer upper edges of the contactor member.

Second abutment surfaces 39 are formed on the body,

which constitute that portion of the internal diameter of the second section which will be contacted by the first abutment surfaces. When the abutment surfaces contact each other, further motion of the floating contactor member away from the axis is prevented, and the recess 35 continues to exist to receive the spring means. The recess boundary surfaces in the embodiments illustrated always are spaced farther apart than the abutment surfaces. The recess is so proportioned and arranged that it will accommodate the spring means without permanent deformation when the abutment surfaces make contact with each other. The size of the recess and the characteristics of'the spring means are, therefore, interrelated, and will be selected to provide the desired spring constant and deflection.

FIGURE 3 indicates that spring means 26 may be inverted from the position shown in FIGURE 4, the same results being attained.

FIGURE 6 indicates that the recess may have different configurations than that shown in FIGURES 15. As an example, a floating contactor member 45 is shown which is identical to that shown in FIGURE 4, with the exception that a slot 46 is formed in it which extends axially. A recess 47 is formed by this slot. Spring means 26 can be accommodated in this recess without permanent deformation.

Recess boundary surface 48 comprises the central portion of abutment surface 49 on body 50, while recess lboundary surface 51 constitutes the bottom of the slot. Abutment surface 52 constitutes the upper portion of the contactor member 45 on each side of slot 46. The retracted position of the floating contactor member is shown in solid line, which occurs when it is contacted by pin 18. The extended position is shown in dotted line, which is the position the contactor member would assume were the pin withdrawn. The remainder of the connector structure of FIGURE 6 is the same as that in FIGURE 1 and is, therefore, not shown in detail. 7

Before the pin is inserted in the socket of FIGURE 1, the floating contactor assumes the position shown in dashed line in both FIGURES 1 and 2, its downward motion being limited by contact with shoulders 30, 31. When the probe or pin is inserted, the floating contactor member will be retracted at least part way to the solidline position. However, the farthest it can be retracted is to the solid-line position, wherein the abutment surfaces contact each other, and further retraction of the contactor member is impossible.

The spring is so designed that permanent deformation will not have occurred by the time it is retracted into the recess formed at this position, and, therefore, no amount of pressure on the contactor member within design limits can damage the spring, because additional force is not transmitted to the spring. Therefore, when the pin or probe is removed, the floating contactor member will be forced back to effectively make contact with the pin, and will also press the pin against the opposite side of the sidewall to make efliective conductive contact at that point. Previous deflections of the spring cannot damage its function.

It will be appreciated that this accomplishes the separation of springback forces from conductivity or durability considerations, and all elements of the structure may, therefore, be made of materials most suited to the purpose intended. For example, the first body section can be made of leaded copper for maximum effective wear and good conductive contact, and the second body section of brass. Both the spring and contactor member can be made of beryllium copper, Berylco No. 25, 1/4 hard, effectively to resist deformation and wear. Other materials can, of course, be used in place of these, this construction giving a far wider choice of materials than is available for making conventional connectors.

This device achieves optimum results with respect to low junction resistance, high resistance to wear in routine connecting and disconnecting, and strong resistance to probe damage.

This invention is not to be limited by the embodiments shown in the drawings and described in the description which are given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

I claim:

1. An electrical socket device comprising a first tubular member having a cylindrical bore extending inwardly from one end thereof,

a second tubular member complementarily circum scribing said first tubular member and secured thereto,

said first tubular member having a portion of the wall thereof removed on one side of the axis of said bore inwardly of said one end thereof,

thereby to define with said second tubular member a recess outwardly of said bore, said first tubular member having longitudinally extending abutment surfaces on either side of said bore where said wall is removed,

said abutment surfaces interconnecting said bore and said second tubular member, a plate floatingly received in said recess,

said plate having a substantially flat undersurface having side portions engageable with said abutment surfaces,

said plate having a substantially flat outer surface the corners of which are engageable with said second tubular member to define a space between said outer surface and said second tubular member, said plate having substantially flat side edges interconnecting said undersurface and said outer surface of said plate,

and converging toward said outer surface, and a leaf spring in said space engaging said outer surface of said plate and said second tubular member for biasing said plate toward said bore.

2. An electrical connector socket comprising an elongated member having a cylindrical bore extending inwardly from one end thereof,

said bore having a recess therein inwardly of said one end,

said recess including an outer surface defined by a segment of a cylinder having a radius of curvature concentric with the radius of curvature of said bore, and a duality of abutment surfaces interconnecting said outer surface and said bore, said duality of abutment surfaces being substantially chordal and arranged so that a plane interconnecting said abutment surfaces is interposed between the axis of said bore and the periphery thereof on the side of said recess, a contact member in said recess,

said contact member being in the form of a substantially flat plate and having outer edges on one side adapted to engage said abutment surfaces for limiting the movement of said plate toward said axis,

said plate having edges on the opposite side engageable with said cylindrical surface of said recess to define a space between said plate and said cylindrical surface,

said plate being shorter in the direction of the axis of said bore than the corresponding dimension of said recess,

and shorter in the direction of the chordal dimension of said recess across said outer surface thereof at said plane interconnecting said abutment surfaces than the corresponding dimension of said recess,

whereby said plate has freedom for limited lateral floating movement in said recess,

and a spring in said space engaging said cylindrical outer surface of said recess and said outer surface of said plate member for biasing said plate member toward the axis of said bore,

said spring being subject to permanent deformation upon a predetermined deflection thereof,

said space being dimensioned to deflect said spring an amount less than said predetermined deflection.

3. An electrical socket device comprising a first tubular member having a cylindrical bore extending inwardly from one end thereof,

a second tubular member complementarily circumscribing said first tubular member and secured thereto,

said first tubular member having a portion of the wall thereof removed on one side of the axis of said bore inwardly of said one end thereof,

thereby to define with said second tubular member a recess outwardly of said bore, said first tubular member'having longitiudinally extending abutment surfaces on either side of said bore where said wall is removed,

said abutment surfaces interconnecting said bore and said second tubular member, a plate floatingly received in said recess,

said plate having a substantially fiat undersurface having edges engageable with said abutment surfaces, said plate being substantially rectangular,

said plate having longitudinal side edges interconnecting said undersurface and said outer surface,

said edges being spaced apart a lesser distance than the chord of said second tubular member at said abutment surfaces,

whereby said plate has freedom for limited lateral floating movement in said recess, said plate being engageable with said abutment surfaces adjacent and inwardly of said side edge, said plate having a substantially flat outer surface the corners of which are engageable with said second tubular member to define a space between said outer surface and said second tubular member,

and a spring in said space engaging said outer surface of said plate and said second tubular member for biasing said plate toward the axis of said bore.

4. A device as recited in claim 3 in which said plate has an end adjacent said one end of said first tubular member,

said end including a surface inclining outwardly with respect to said bore from said undersurface toward said outer surface of said plate.

5. A device as recited in claim 3 in which said spring means is a leaf spring engaging said second tubular member at said outer surface of said plate,

said leaf spring being elongated and longitudinally aligned with said bore.

6. A device as recited in claim 3 in which said side edges of said plate interconnecting said undersurface and said outer surface are convergent toward said outer surface. 7. I A connector socket comprising an elongated member having a cylindrical bore theresaid member having a recess in one side of said bore,

said recess having an outer cylindrical surface the radius of curvature of which is concentric with the radius of curvature of said bore, said recess having spaced longitudinal side edges interconnecting said bore and said outer cylindrical surface,

and having spaced end edges interconnecting said bore and said outer cy indrical surface, a plate member in said recess,

said plate member having side edges spaced apart a lesser distance than the spacing between opposite portions of said outer cylindrical surface adjacent said side edges of said recess, said plate member having end edges spaced apart a lesser distance than the spacing between said end edges of said recess,

whereby said plate member is floatingly received in said elongated member, said plate member having an inner surface having portions adjacent said side edge of said plate member engageable with said side edges of said recess,

for limiting the movement of said plate member inwardly toward the axis of said bore, said plate member having an outer surface of smooth continuous contour relatively more planar than said outer cylindrical surface, said plate member being engageable with said outer cylindrical surface intermediate said side edges of said plate member and said outer surface thereof,

thereby providing a space between said outer surface of said plate member and said outer cylindrical surface intermediate said side edges of said plate member upon such engagement, and a spring loosely received in said space engaging said outer cylindrical surface of said recess and said outer surface of said plate member for biasing said plate member toward said axis of said bore,

said spring being subject to permanent deformation upon a predetermined deflection thereof,

said space being dimensioned such that said spring is deflected an amount less than said predetermined deflection when said plate member so engages said outer cylindrical surface.

References Cited by the Examiner UNITED STATES PATENTS 1,093,972 4/1914 Cady 339-225 X 2,188,789 1/1940 Kimball 339255 X 2,221,651 11/1940 Pelz 339-255 2,318,207 5/1943 Ellis 339255 X 2,386,611 10/1945 Ileman 339255 X 2,436,280 2/1948 Wright 339255 2,753,392 7/1956 Hebeler 339--255 X 3,101,986 8/1963 Lyman 339-255 FOREIGN PATENTS 753,412 8/1933 France.

9,305 1914 Great Britain. 187,791 10/ 1937 Switzerland.

JOSEPH D. SEERS, Primary Examiner.

R. E. MOORE, Assistant Examiner.

Claims (1)

1. AN ELECTRICAL SOCKET DEVICE COMPRISING A FIRST TUBULAR MEMBER HAVING A CYLINDRICAL BORE EXTENDING INWARDLY FROM ONE END THEREOF, A SECOND TUBULAR MEMBER COMPLEMENTARILY CIRCUMSCRIBING SAID FIRST TUBULAR MEMBER AND SECURED THERETO, SAID FIRST TUBULAR MEMBER HAVING A PORTION OF THE WALL THEREOF REMOVED ON ONE SIDE OF THE AXIS OF SAID BORE INWARDLY OF SAID ONE END THEREOF, THEREBY TO DEFINE WITH SAID SECOND TUBULAR MEMBER A RECESS OUTWARDLY OF SAID BORE, SAID FIRST TUBULAR MEMBER HAVING LONGITUDINALLY EXTENDING ABUTMENT SURFACES ON EIHER SIDE OF SAID BORE WHERE SAID WALL IS REMOVED, SAID ABUTMENT SURFACES INTERCONNECTING SAID BORE AND SAID SECOND TUBULAR MEMBER, A PLATE FLOATINGLY RECEIVED IN SAID RECESS, SAID PLATE HAVING A SUBSTANTIALLY FLAT UNDERSURFACE HAVING SIDE PORTIONS ENGAGEABLE WITH SAID ABUTMENT SURFACES,

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