EP0133377A2

EP0133377A2 - miniature electrical terminal for low energy electronic circuits

Info

Publication number: EP0133377A2
Application number: EP84305329A
Authority: EP
Inventors: Thomas Miller Cairns
Original assignee: Ford Werke GmbH; Ford France SA; Ford Motor Co Ltd; Ford Motor Co
Current assignee: Ford Werke GmbH; Ford France SA; Ford Motor Co Ltd; Ford Motor Co
Priority date: 1983-08-05
Filing date: 1984-08-06
Publication date: 1985-02-20
Also published as: EP0133377A3; JPS6044980A; ZA844871B; ES292501Y; AU3160584A; BR8403528A; CA1209661A; ES292501U

Abstract

An electrical connector formed to mate with a cylindrical pin-type connector and establish separate lines of electrical contact tangentially along a portion of the length of the pin connector by the use of resiliently hinged «V» shaped contacts. An insulative housing for the connector provides a protruding locking element and a removable locking wedge to secure the connection in place.

Description

Field of the Invention

The present invention is directed to the field of electrical connectors and more specifically to the area of male and female electrical connector configurations ideally suited for low energy electronic circuits.

SUMMARY OF THE INVENTION

Microscopic evaluation of prior art electrical connector terminal designs, which have undergone environmental stress such as thermal expansion and contraction as well as mechanical vibrations, have disclosed wear tracks and metallic residue resulting from the physical movement of one electrical contact on another. The electrical effect of this movement is seen as a resistance increase through the contact interface as a result of inorganic insulating films and residue which have been eroded from the metallic surfaces of the contacts. In low energy electronics, such as employed in microcircuit devices which generate low current signals, such resistance changes are unacceptable because they cause erroneous information to be communicated.
The present invention is intended to overcome the problems found in prior art terminals by providing an electrical connector which has a prolonged stable life with a constant low interface resistance. The present invention provides an electrical connector in which the contact geometry and mechanical force loading are such that physical movement between the mated male and female members is substantially reduced or eliminated.
According to a first aspect of the invention, there is provided a female electrical connector for mating with a male cylindrical pin type connector, comprising body means having a first end portion for accepting and making electrical contact with said male pin connector and a second portion for supporting said first end portion; and a cylindrical hood means mounted concentrically around said body means and having a first apertured end portion defining the maximum diameter of said male pin connector that may be inserted into said body means, wherein said first end portion of said body means is formed as a pair of opposing "V" shaped contacts having respective apexes adjacent the inner surface of said cylindrical hood means and the opposing surfaces of said contacts being generally planar and tangential to said male pin connector, when inserted, to provide four substantially parallel lines of electrical contact with said male pin connector.
The invention also provides an insulative housing for a female connector as set out above defining a cylindrically shaped inner chamber having an open first end for accepting the insertion of said female connector and a second apertured end that is approximately the same diameter as said aperture of said hood so as to provide a stop for further insertion of said female connector, an electrical insulator between the first apertured end of said hood and the exterior of said housing and access to said female connector by said male pin connector.
The invention will now be described further, by way of example, with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is an exploded view of the matable components of the present invention;
Fig. 2A is an isometric partial cross-section of the female connector assembly of the present invention;
Fig. 2B is a cross-section of the female connector assembly taken along lines 2B-2B shown in Fig. 2A;
Fig. 2C is an elevational cross-section of the female electrical connector shown in Fig. 2A;
Fig. 3A is an isometric partial cross-section of the mated male and female connector portions of the present invention;
Fig. 3B is a cross-section of the assembly taken along the lines 3B-3B shown in Fig. 3A;
Fig. 3C is an elevational cross-section of the present invention shown in Fig. 3A;
Fig. 4 is an isometric partial cross-section of a housing for the female electrical connector of the present invention;
Fig. 5 is a partial cross-section of the housing illustrated in Fig. 4 assembled with a locking wedge;
Fig. 6 is a partial cross-section illustrating the housing containing the female electrical connector in a locked configuration.
Fig. 7 is a comparison plot of resistance measurements taken during a number of temperature cycles.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT.

An exploded view of the present invention is shown in Fig. 1 in which a cylindrical male pin connector 4 is illustrated in an exploded view along with a female connector 20. The male pin connector 4 includes an elongated contact portion 10 that is generally cylindrical in shape with a tapered nose portion 12. An enlarged stop 14 defines the insertion length of the cylinder 10. On the opposite side of the stop 14, a depressed area 16 is provided for locking the pin in an insulated housing, such as that shown in Fig. 4. The male pin connector 4 is soldered or crimped to an electrical conductor in a conventional manner at its wire end 18.
The female connector 20 includes a main body member 22 formed as a hollow, generally cylindrical unit and a hood element 50. The body member 22 includes a first end portion 29 for accepting and making electrical contact with the cylindrical portion 10 of the male pin connector 4. The body element 22 also contains a second portion 21 which has an inner diameter measurement greater than that diameter of the cylinder 10 to provide clearance and to provide structural support for the first end portion 29. The first end portion 29 of the body element 22 is formed as a pair of opposing "V shaped contacts 23 and 24 that are resiliently sprung and individually connected to the second body portion 21 via integral biasing hinges 34 and 36 formed by cutouts 38 and 40. The opposing °V° shaped contacts 23 and 24 are formed to have generally planar inner surfaces 27 and 28 joined at the apex 25, and surfaces 30 and 32 joined at the apex 26. To the rear of the body element 22, a depressed area 44 is formed to provide a seat for a locking member in an insulative connector such as that shown in Fig. 4. The female connector 20 is connected to an electrical conductor at its terminal end 46 via solder or a crimping tab 48.
The hood 50 shown in Fig. 1, is assembled to the female connector body 22 as shown in Fig. 2A by a conventional crimping technique as indicated by numeral 54 in Fig. 2C. The inner surface 51 of the hood 50 is adjacent the apexes 25 and 26 and provides a limit to the outward movement of those apexes when the male pin connector 4 is inserted therein.
Fig. 2B is a cross-section of the assembly shown in Fig. 2A taken along section lines 2B-2B. In this figure, a dimension D_l is shown as the maximum relaxed distance between opposing planar surfaces of the "V" shaped contacts 23 and 24. The contacts 23 and 24 are formed so that the dimension D_l is less than the outer diameter D₂ of the cylinder 10 on the male pin connector 4. On the other hand, the inner diameter of the second portion 21 of the body element 22 is greater than D₂.
Fig. 2C is an elevational cross-section of the assembly shown in Fig. 2A and serves to illustrate the tapered arrangement of the "V shaped contacts 23 and 24 as they extend from the second portion 21 of the connector body 22 through hinge elements 34 and 36, respectively. The aperture 52 is also shown as having a diameter D₃ which is greater than D₂ and D_l. The aperture 52 is, of course, coaxially positioned with respect to the body element 22 in order to center the pin connector 4 and prevent collision with the edges of contacts 23 nd 24 when the nose end 12 of the male pin connector 4 is inserted therein.
Figs. 3A, 3B and 3C illustrate the assembly, whereby the male pin connector 4 is fully mated with the female connector 20. Upon initial insertion into the aperture 52 of the hood 50, the nose end 12 of the pin connector 4 is in contact with the inner surfaces 27, 28, 30 and 32. The "V shaped contacts 23 and 24 yiueld in the path of least resistance offered by biasing hinges 34 and 36 until the apexes 25 and 26 abut the inner surface 51. Meanwhile, the surfaces 27, 28, 30 and 32 are caused to be spread apart and thereby increasing the included angle at the apex and also provide compressive tangential contact to the outer surface of the cylinder 10 of the male pin connector 4. This tangential contact is defined as separate lines of contact L_l, L₂, L₃ and L₄ which run the length of the "V shaped contacts 23 and 24. In this manner, the cylinder portion 10 of the pin connector 4 is held in compressive suspension and the contact points are substantially permanent throughout the life of the connection, even though subjected to vibrational and thermal forces.
Tests were performed by measuring resistance values of a conventional connector and those of the present invention subjected to a series of high and low temperature cycles in order to evaluate and compare their relative performances. Fig. 7 illustrates the results of those cyclical temperature tests wherein the conventional connector resistance values (taken at 100 a) are plotted as X, and the present invention resistance values are plotted as Y. It is readily apparent that the present invention offers improved stability and long life over conventional connectors due to its unique configuration.
An insulative housing 80 is shown in Fig. 4 which is utilized to support an array of female electrical conductors, such as described above, in a positively locked configuration having their open ends electrically insulated from the external surface of the housing. The insulative housing 80 is formed to have an elongated chamber 82 which a diameter which is adequate to receive female connector 20 in an open end 86. At the opposite end of the chamber 82, an apertured stop 84 is defined that is approximately the same diameter as the aperture 52 on the hood 50. The size of the aperture 84 is designed to accept the insertion of the pin connector cylinder 10 and orients the nose end 12 so as to be coaxial with the female connector 20. A resilient locking arm 88 is formed as an extension of the insulative housing 80 and contains a locking tab 90 which protrudes into the chamber 82, so as to bear against the female connector as it is inserted into the chamber 82 and to hold that connector in place when it is fully inserted. A recess 89 is formed within the insulative housing 80 so as to be adjacent the resilient locking arm 88. The recess 89 is accessible to receive a locking wedge 100 that is formed to fit in the recess 89 so as to restrict any movement of the locking arm 88 from its protruding position as shown in Fig. 4. The locking wedge 100 contains a receding surface 102 which abuts against a lower surface 92 of the resilient locking arm 88 and prevents any downward movement of the tab 90 once the locking wedge is inserted. A chamber portion 104 of the locking wedge 100 provides a bottom element for the chamber 82 when the locking wedge 100 is installed and an extending portion 106 provides a sectored . completion for the apertured stop 84. A key 94 and a keyway 108 are also provided on the respective insulative housing 80 and the locking wedge 100 to provide alignment guidance upon insertion.
Fig. 5 illustrates the insulative housing 80 with the locking wedge 100 inserted in the recess 89. Fig. 6 illustrates the complete assembly of the female electrical connector 20 installed within the insulative housing 80 and locked in position by the tab 90 positioned in the depression 44 and the locking wedge 100 inserted in the recess 88. Of course, during installation, the locking wedge 100 is removed prior to insertion of the female connector 20 through the end 86 of the chamber 82. As the female connector 20 is inserted, the forward end of the hood 50 contacts the ramped surface 91 of the resilient locking arm 88 and causes the arm to deflect in a downward manner until the depression 44 is over the locking tab 90. At that point, the resilient locking tab 90 will return to its normal position and retain the female connector 20 within the chamber 82. The function of the then inserted locking wedge 100 is to insure and strengthen the locking function of the tab 90 as it bears against the connector 20.

Claims

1. A female electrical connector for mating with a male cylindrical pin type connector, comprising body means having a first end portion for accepting and making electrical contact with said male pin connector and a second portion for supporting said first end portion; and a cylindrical hood means mounted concentrically around said body means and having a first apertured end portion defining the maximum diameter of said male pin connector that may be inserted into said body means, wherein said first end portion of said body means is formed as a pair of opposing "V" shaped contacts having respective apexes adjacent the inner surface of said cylindrical hood means and the opposing surfaces of said contacts being generally planar and tangential to said male pin connector, when inserted, to provide four substantially parallel lines of electrical contact with said male pin connector.

2. A connector as in Claim 1, wherein said opposing "V" shaped contacts are biased inwardly towards each other at a maximum distance that is less than the diameter of said male pin connector.

3. A connector as in Claim 1 or 2, wherein said opposing "V" shaped contacts are cantilever supported to said second portion by an integrally formed hinge connection.

4. A connector as in Claim 1, 2 or 3,_' wherein said opposing surfaces of said pair of "_V" shaped contacts are spread apart and the respective apexes are forced into contact with the inner surface of said hood means by the insertion of said male pin connector into said body to thereby provide intimate electrical contact with the male pin connector.

5. A connector as in any preceding claim, wherein said second portion of said body means is substantially cylindrical in shape and is of a diameter that is greater than the diameter of said male pin connector.

6. An insulative housing for a female connector as in Claiml defining a cylindrically shaped inner chamber having an open first end for accepting the insertion of said female connector and a second apertured end that is approximately the same diameter as said aperture of said hood so as to provide a stop for further insertion of said female connector, an electrical insulator between the first apertured end of said hood and the exterior of said housing and access to said female connector by said male pin connector.

7. A housing as in Claim 6, wherein said inner chamber contains a resilient locking arm that bears against said female connector when fully inserted in said chamber to retain same within said chamber.

8. A housing as in Claim 7, further including a recess adjacent said locking arm and accessible from the exterior of said housing and a removable wedge means formed to be inserted into said accessible recess to provide compressive forces that prevent said resilient locking arm from becoming disengaged from said female connector.