Electrical Connector

Abstract

In a preferred form, this disclosure relates to an electrical connector means having a tin plated metal female terminal and a tin plated male terminal made from a metallic material which is softer than that of the female terminal. The female terminal has a body portion which is adapted to be connected with an electrical lead, such as a printed circuit on a printed circuit board, and an elongated ferrule portion which is C-shaped, as viewed in cross section. The male terminal is generally cylindrically shaped and has a knurled shank portion and with the apices of the individual knurls lying on a circumscribed diameter which is greater than the internal diameter of the C-shaped ferrule portion of the female terminal. The male terminal is connected to the female terminal by intersecting the same into the ferrule portion which causes the C-shaped ferrule portion to radially expand and the knurls on the shank portion to plastically deform whereby the male terminal is connected to the female terminal as a result of the contracting force exerted by the female terminal and the plastic deformation of the knurls of the male terminal.

Description

The present invention relates to an electrical connector means.

Heretofore, electrical connectors comprising a female terminal having a radially expandible ferrule portion and a male terminal in the form of a cylindrical pin which was insertable into the ferrule portion of the female terminal have been provided. The male terminal upon insertion into the ferrule portion of the female terminal caused the ferrule portion to be radially expanded and engage the cylindrical pin with a contracting force. One of the problems with such prior connectors is that they relied solely on the contracting force of the ferrule portion of the female terminal to insure a mechanical connection as well as providing a mechanical interface between the terminals for electrical contact. Since it is extremely difficult to make the parts so that they are perfectly round or have a constant diameter, the resulting connection often provided for only line contact at diametral opposite locations between the cylindrical pin and the ferrule portion of the female terminals. This oft times enabled corrosion to set in which in turn resulted in poor electrical conduction between the connecting parts.

The present invention provides an electrical connector means of the above-noted type, but in which the problems noted with the prior art connectors are overcome. Accordingly, a broad object of the present invention is to provide a new and improved electrical connector of the above noted type and which overcomes the above-noted problems.

Another object of the present invention is to provide a new and improved electrical connector of the above-noted type, and in which a good mechanical and electrical connection is achieved by providing for area contact between the connecting parts and in a manner which inhibits corrosion from setting in so that electrical conductivity is not affected.

A still further object of the present invention is to provide a new and improved electrical connector having a female terminal which includes a radially expandible ferrule portion which is C-shaped, as viewed in cross section, and a male terminal which is generally cylindrical in shape and has a knurled shank portion, and in which the ferrule portion of the female terminal is caused to radially expand upon insertion of the male terminal and the knurls on the male terminal are caused to plastically deform whereby good area contact between the terminals is established to maximize electrical conductivity therebetween.

A further object of the present invention is to provide a new and improved electrical connector, as defined in the next preceding object, and in which both of the terminals are tin plated so that when the male terminal is inserted into the ferrule portion of the female terminal a localized cold welding effect takes place therebetween so as to further minimize corrosion.

The present invention further resides in various novel constructions and arrangement of parts, and further objects, novel characteristics and advantages of the present invention will be apparent to those skilled in the art to which it relates and from the following detailed description of the illustrated embodiments thereof made with reference to the accompanying drawings forming a part of this specification and in which similar reference numerals or characters are employed to designate corresponding parts throughout the several views, and in which:

FIG. 1 is a vertical cross-sectional view of a housing means for supporting stacked printed circuit boards and which embodies the novel electrical connector means of the present invention;

FIG. 2 is a cross-sectional view taken approximately along line 2--2 of FIG. 1;

FIG. 3 is a side elevational view of the male terminal of the electrical connector means of the present invention;

FIG. 4 is an enlarged fragmentary sectional view taken approximately along line 4--4 of Figure 3; and

FIG. 5 is an enlarged fragmentary sectional view taken approximately along line 5--5 of FIG. 1.

The present invention provides a novel electrical connector means 10. Although the electrical connector means 10 of the present invention could be used in various types of applications, it is particularly susceptible for use in electrically connecting various circuits on different stacked printed circuit boards together. For the purposes of illustration and description, it will be herein shown and described as being used for the latter purpose.

The electrical connector means 10 broadly comprises a female terminal 12 and a male terminal 14. The female terminal 12 has a body portion 15 in the form of a flat strip of sheet metal and a ferrule portion 16 integrally connected with one end of the body portion 15. The ferrule portion 16 extends transversely or perpendicularly to the body portion 15 and is C-shaped, as viewed in cross section, to define a pair of opposed semicircular arms or sections 18. The ferrule portion 16 is resilient or elastic and is radially expandable and contractible. The arms 18 are integrally connected at one end and have their opposite ends spaced from each other to define a gap 20 therebetween. The ferrule portion 16 has an internal diameter d of the given or predetermined nominal value. It will, of course, be understood that the internal diameter d can vary between maximum and minimum limits from the given nominal diameter within established tolerance limitations.

The male terminal 14 has a head portion 24, a shank portion 26 and an end portion 27. The head portion 24 is in the form of a cylindrical pin which is rounded at its upper end and which is adapted to be inserted within a suitable mating female terminal. The shank portion 26 is generally cylindrical in shape and has a plurality of axially extending, circumferentially spaced knurls 28 thereon. Adjacent knurls 28 define axially extending recesses 29 therebetween. The knurls 28 are generally triangular in shape, as viewed in cross section, and have apices 30 which lie on a circumscribed circle 31 having a minimum diameter d.sub.1 which is greater than the maximum diameter d of the ferrule portion 16 of the female terminal 12. The tapered portion 27 is rounded at its bottom 32 and progressively, axially tapers radially inwardly proceeding from the shank portion 26 towards its rounded bottom 32.

The female terminal 12 is made from a metal material which is harder than the metal material from which the male terminal 14 is made. Preferably the female terminal is made from a phosphor bronze metal and the male terminal is made from brass. Both the male and female terminals are also preferably tin plated, as indicated by reference numerals 33 and 34.

The male terminal 14 is connectable to the female terminal 12 by inserting the same into the ferrule portion 16. As the shank portion 26 is inserted into the ferrule portion 16, the knurls 28 will cause the ferrule portion 16 to be radially expanded, since the diameter d.sub.1 of the knurls 28 is greater than the internal diameter d of the ferrule portion 16. The elastic arms 18 of the ferrule radially expand and exert a contracting spring force on the shank portion 26 of the male terminal 12. Also, as the shank portion 26 is received within the ferrule portion 16, the knurls 28 will be plastically deformed. That is, their apices 30 will be flattened and rounded and with the metal therefrom being cold flowed into the recesses 29 between the adjacent knurls 28, as shown in FIG. 5. Additionally, since both the male and female terminals 14 and 12 are tin plated, a localized cold welding or galling between the knurls 28 and the ferrule portion 16 of the female terminal 12 takes place.

From the foregoing, it can be seen that a mechanical connection between the male and female terminals is achieved by (1 ) the contracting spring force of the ferrule portion 16 against the shank portion 26 of the male terminal, (2) the plastic deformation of the knurls 28 on the male terminal 14 which provides area contact at circumferentially spaced locations with the ferrule portion 16 of the female terminal so as to increase a frictional engagement therebetween and (3) due to the localized cold welding between the mechanical interfaces between the two terminals. The above-noted connection also insures good electrical contact since (1) there is area contact between the male and female terminals and (2) the localized cold welding between the tin plated terminals inhibits corrosion or oxide build-ups on the terminals, since the localized cold welding eliminates a mechanical interface. Insertion of the male terminal 14 into the female terminal 12 is facilitated by a rounded tapered end 24.

As shown in FIG. 1, the electrical connector means 10 of the present invention is particularly useful in applications utilizing stacked printed circuit boards 40, such as in an electronic control package or assembly for controlling operation of a fuel injection system for an automotive vehicle. As shown in FIG. 1, the individual printed circuit boards 40 are supported on individual housings 41 having a central opening 42 which receives the printed circuit board 40. The female terminal 12 is connected to the printed circuit board 40 and at locations which are vertically aligned with other female terminals 12. To this end the individual female terminals 12 have a depending leg portion 45 which is secured to the printed circuit board and which can be suitably electrically connected with the printed circuit or circuits thereon. The ferrule portions 16 are adapted to be received within counterbored openings 46 in the housings 41 and with the lower end thereof resting on a shoulder 47 in the housing at the end of the counterbore. The body portion 15 is received within a slot 48 in the inner side wall of the housing.

With the female terminals 12 vertically aligned, it is possible for the male terminal 14 to be connected to a plurality of the female terminals 12 so as to electrically interconnect one circuit board with another circuit board.

Another advantage of the present invention is that the male member 14 can be disconnected and later reconnected to the various female terminals 12 a number of times.

Although the illustrated embodiment hereof has been described in great detail, it should be apparent that certain modifications, changes, and adaptations may be made in the illustrated embodiment, and that it is intended to cover all such modifications, changes and adaptations which come within the spirit of the present invention.

Claims

What is claimed is:

1. An electrical connector means comprising: a metal female terminal having a body portion which is adapted to be connected with an electrical lead and an elongated ferrule portion which is C-shaped, as viewed in cross section, said C-shaped ferrule portion being elastic and radially expandable and contractible, said C-shaped portion having a given nominal internal diameter; a metal cylindrically shaped male terminal having a knurled shank portion and with the apices of the individual knurls lying on a circumscribed circle having a nominal diameter which is greater than the given diameter of said C-shaped ferrule portion of said female terminal, said female terminal being made from a metal which is harder than the metal of the male terminal, said male terminal being connectable to said female terminal by inserting the same into the ferrule portion, said knurled shank portion engaging said ferrule portion and causing the same to radially expand and said knurls plastically deforming as said male terminal is inserted therein whereby said male terminal is connected to the female terminal as a result of the contracting force exerted by the female terminal and by the plastic deformation of the knurls and with the latter also providing for area contact between the terminals.

2. An electrical connector means comprising: a tin plated metal female terminal having a body portion which is adapted to be connected with an electrical lead and an elongated ferrule portion disposed transversely of the body portion and which is C-shaped, as viewed in cross section, said C-shaped ferrule portion being resilient and radially expandable and contractible, said C-shaped ferrule portion having an internal diameter within maximum and minimum tolerance variations from a given nominal internal diameter, a tin plated metal cylindrically shaped male terminal having a knurled shank portion and with the apices of the individual knurls lying on a circumscribed diameter which is greater than the maximum internal diameter of said C-shaped ferrule portion of said female terminal, said knurls extending axially of said shank portion, said female terminal being made from a metal which is harder than the metal of the male terminal, said male terminal being connectable to said female terminal by inserting the same into the ferrule portion thereof, said knurl shank portion engaging said ferrule portion and causing the same to be radially expanded and said knurls plastically deforming as the male terminal is inserted therein whereby said male terminal is connected to the female terminal as a result of the contracting force exerted by the female terminal, by the plastic deformation of the knurls and by the localized cold welding which takes place as a result of the tin to tin interface between the terminals, said plastic deformation of the knurls and said localized cold welding also providing for area contact between the terminals so as to insure electrical conduction therebetween.

3. An electrical connector means for use with a plurality of stacked printed circuit boards comprising: a plurality of aligned, but spaced apart female terminals which are adapted to be connected at one end to the printed circuit boards and the other end received within counterbored apertures in a support housing, said female terminals having a body portion which is adapted to be connected with the printed circuit boards and an elongated ferrule portion which is disposed transversely of the body portion and is received within the apertures of the housing, said ferrule portion being C-shaped, as viewed in cross section, and having an internal diameter within established tolerance limitations from a given nominal internal diameter, a metal cylindrically shaped male terminal having an elongated knurled shank portion and with the knurls extending axially of the shank portion, said knurls having their apices lying on a circumscribed diameter which is greater than the maximum diameter of the C-shaped ferrule portion of the female terminal, said female terminals being made from a metal which is harder than the metal of the male terminal, said male terminal being connectable to said aligned female terminals by inserting the same into the ferrule portions thereof, said knurl shank portion engaging said ferrule portions of the female terminals and causing the same to radially expand and the knurls plastically deforming as the male terminals are inserted therein whereby the male terminal is connected to the female terminals as a result of the contracting force exerted by the female terminals and by the plastic deformation of the knurls and with the latter also providing for an area contact between the terminals to insure electrical conductivity therebetween.