Electrical Connector Having Improved Contact Retention Means

Abstract

Electrical connector comprises insulating housing having contact receiving cavities extending therethrough. Each cavity has a rearwardly facing shoulder adjacent to the mating face of the housing and a forwardly facing shoulder adjacent to its rearward face of the housing these shoulders being on opposite sides of the cavity. An electrical contact terminal is located in each cavity and has a spring means thereon which is effective between the terminal and the side of the cavity on which the rearwardly facing shoulder is located so that the terminal is resiliently biased against the opposite side of the cavity. Terminal is thereby retained against forward movement by the rearwardly facing shoulder and against rearward movement by the forwardly facing shoulder. Removal of contact from the cavity is accomplished by inserting a thin tool into the contact, moving it laterally away from the side of the cavity on which the forwardly facing shoulder is located, and pulling the conductor to which the contact is secured.

Description

BACKGROUND OF THE INVENTION

This invention relates to multi-contact electrical connectors of the type comprising an insulating housing having a plurality of cavities extending therethrough and contact terminals in the cavities. The terminals are secured, by crimping or soldering to electrical conductors so that when the connector is mated with a complementary connecting device, the conductors extending to the two connectors are electrically coupled or connected to each other.

It is now common practice in the electrical connector art to design the connector housing and the contact terminals in a manner which permits removal of an individual terminal, or of a group of terminals, from a housing for replacement or repair. In order to achieve this capability, retention lances in the form of obliquely extending springs are provided on the contact terminals which are adapted to engage shoulders in the cavities in the housing. When a terminal of this type is inserted into a cavity, the retention lance is resiliently deflected until the terminal is fully inserted into the cavity at which time the lance returns to its normal position and prevents rearward movement of the terminal from the cavity. This type of retention system is shown, for example, in the U.S. Pat. Nos. 3,389,371, 3,439,314 FIG. 2,) 3,351,849 and in many other previously issued patents.

In order to permit removal of the terminals from a connector housing, it is necessary to provide for access of an extraction tool. These extraction tools depress the retention lance and disengage it from the retention shoulder so that the terminal can then be moved axially from the cavity. Access for the extraction tool is usually provided by simply making the cavity in the connector housing oversize so that the extraction tool can be moved axially into the cavity when a terminal is being removed.

Under some circumstances, it is impractical or impossible to provide clearance to permit the extraction tool to move axially into the contact receiving cavity of the connector housing. For example, FIG. 2 of U.S. Pat. No. 3,439,314 shows a socket-type terminal having a rectangular cross-section which occupies virtually the entire cross-section of the cavity in which it is mounted and an extraction tool cannot be inserted axially into the cavity. Access is provided for the extraction tool in accordance with the teachings of this prior art patent by providing an opening in the side of the connector housing which communicates with the cavity. The extraction tool can be inserted laterally with respect to the axis of the contact receiving cavity to engage the lance on the terminal and disengage the lance from the retention shoulder in the cavity. The retention system and the extraction tool access arrangement shown in the patent to Lightner U.S. Pat. No. 3,439,314 is satisfactory where the connector has only a single row of contact terminals therein but if the connector has more than two rows, it is obviously impossible to provide access to the center row of terminals in the connector and the retention system shown in Lightner et al is therefore limited to connectors having at the most two rows of terminals.

The instant invention is directed to the achievement of an improved retention system for the electrical contact terminals in a multi-contact electrical connector and particularly to a system which does not require clearance in the contact receiving cavity of the connector for an extraction tool. It is accordingly an object of the invention to provide an improved multi-contact electrical connector. A further object is to provide an improved retention system for retaining electrical contact terminals in the contact receiving cavities of an electrical connector. A still further object is to provide a retention system which permits close spacing of the contact terminals in the connector housing. A still further object is to provide a retention system which permits removal of the contact terminals from the housing but which does not require clearance for an extraction tool in the contact receiving cavities of the housing.

These and other objects of the invention are achieved in a preferred embodiment thereof which is briefly described in the foregoing abstract, which is described in detail below, and which is shown in the accompanying drawings in which:

FIG. 1 is a perspective view showing a typical multi-contact electrical connector assembly comprising a receptacle and a plug;

FIG. 2 is a perspective view of a sectioned portion of a connector insert or housing in accordance with the instant invention which would be contained in the connector plug 2 of the assembly of FIG. 1;

FIG. 3 is a cross-sectional view of the connector insert of FIG. 2 showing an electrical contact terminal in alignment with one of the contact receiving cavities in the insert preparatory to insertion of the terminal into the cavity, this view being taken along the lines 3--3 of FIG. 6;

FIGS. 4 and 5 are viewed similar to FIG. 3 but illustrating the insertion of the terminal into the cavity, FIG. 5 being taken along the lines 5--5 of FIG. 6;

FIG. 6 is an orthographic view of the rearward side of the insert shown in FIG. 2;

FIG. 7 is a perspective view of an electrical contact terminal of the type adapted to be received in the cavities of the insert shown in FIG. 2;

FIG. 8 is a perspective view of a tool for removing contact terminals from the housing or insert of FIG. 2; and

FIG. 9 is a perspective view of an electrical connector in accordance with the invention having a plurality of rows of terminals therein,

Referring first to FIG. 1, a typical electrical connector assembly comprises a plug 2 and a receptacle 4, the receptacle 4 being mounted on the wall of a container 8. The receptacle 4 has an outer hood 9, which surrounds, and is spaced from, an inner hood 10 within which there are contained a plurality of electrical contact pins 12. It will be understood that these contact pins extend into the interior of the container 8 and are electrically connected to conductors which extend to electrical components or parts within the container. As is common practice, the receptacle 4 is secured to the wall of the container 8 by suitable fasteners 6.

The plug 2 comprises a metallic shell 15 within which there is mounted a dielectric insert or housing 20 shown in FIGS. 2-5. The connector plug 2 may be of a general type disclosed in and claimed in my copending application filed the same day as the instant application Ser. No. 105,207 or may be of any other desired type. In as much as the instant invention is directed to the retention means for retaining contact terminals in the cavities in the insert or housing 20, it is unnecessary to describe the manner of mounting the insert 20 in the shell 5. Reference is made to my above-identified copending application for such details.

The housing has a plurality of cavities 22 extending therethrough from its rearward face 24 to its forward or mating face 26, each of these cavities being adapted to receive an electrical contact terminal of the general type shown at 52, in FIG. 7 and described in greater detail below. Each cavity 22 in the housing or insert 20 has an entrance portion 28 at its left hand end in the form of inclined surfaces which function to guide the contact pins 12 into the cavity when the plug part 2 is mated with the receptacle 4. The entrance portion 28 merges with a short section 32 of the cavity which has a rectangular cross-section of reduced area as compared with the remainder of the cavity. The reduced cross-sectional area 32 extends to a rearwardly facing shoulder 34 and a horizontal ledge 36 extends rightwardly from the shoulder for short distance. A ramp 38 is inclined downwardly from the end of the ledge 36 and merges with an intermediate section of the cavity which is of uniform rectangular cross-section. The lower sidewall or floor wall 40 of the cavity, as viewed in FIG. 3, extends uninterruptedly to the right hand end of the housing as indicated. The opposite wall, that is the upper side-wall 42 of the cavity is provided with a rightwardly or forwardly facing shoulder 44 which is spaced from the rearwardly facing shoulder 34 and which is formed by a projection 46 extending downwardly from the upper wall of the cavity. The projection 46 extends only partially across the cavity and forms a laterally facing shoulder 48 which is opposed to the left hand side of the cavity as viewed in FIG. 6. The rearward entrance portion 50 of each cavity is inclined as indicated in FIG. 3 for cooperation with a sealing gland which is contained in the shell 15 as more fully described in my above-identified copending application. The contact retention system of the instant invention can, of course, be used in unsealed connectors in which case the housings might take a variety of forms.

Cavities of the configuration shown in the drawing are particularly adapted to receive electrical contact terminals 52 of a general type disclosed more fully in the previously identified Lightner et al. U.S. Pat. No. 3,439,314. Such terminals have a generally rectangular or square socket portion 54 of sheet metal and have contact springs 56 on two opposite sides thereof which are adapted to engage an inserted contact pin. Each terminal is crimped at 60 onto a conductor 16, the conductor in the disclosed embodiment of the invention comprising a conductor in a flat conductor cable 14 as more fully described in the patent to Huffnagle U.S. Pat. No. 3,395,381 although the principles of the instant invention can be employed with terminals secured to conventional wire conductors. A retention lance 58 is struck from the side 59 of the socket portion of the terminal on one side thereof; that is the lance is not centered on the side 59 but is struck from stock metal on the lower portion of this side and does not extend beyond the center of the side 59 of the terminal. As will be explained below, the off-center location of the lance 58 and the limited extent of the shoulders 44 in the cavities prevent the insertion of the cable into the housing in other than the proper orientation.

When the principles of the instant invention are being practiced with flat conductor cable as indicated at 14 in FIG. 1, a terminal 52 is first crimped unto each of the conductors 15 of the cable as explained in the above-identified Huffnagle patent. Thereafter, the cable is aligned with the insert 20 as shown in FIG. 3 with the terminals 52 oriented such that the lances 58 are in alignment with the lower sides or floors 40 of the cavities. The entire cable is then moved leftwardly relative to the housing or insert as illustrated in FIGS. 4 and 5 until the forward ends of the terminals move against the rightwardly facing shoulders 34 of the cavities. It will be apparent that during such movement of the terminals, the lances 58 of the terminals are deflected as illustrated in FIG. 4 and, after movement of the terminals over the ramps 38 in the cavities, the lances will tend to return to their normal positions and urge the terminals upwardly in the cavities. The edges 62 of the terminals will then be disposed against the forwardly facing shoulders 44 of the cavities to prevent rightward movement of the terminals or cable relative to the housings. Leftward movement of the terminals is, of course, prevented by the rightwardly facing shoulders 34 in the cavities which are engaged by the leading edges of the terminals.

As previously mentioned, the cable cannot be permanently inserted into the housing if the cable is not properly oriented, that is, it cannot be inserted in a reverse orientation from that shown in the drawing. This feature can be appreciated if it is noted that if the technician should attempt to insert the cable when it is in a reverse orientation from that shown in FIG. 3, (an orientation such that the lances 58 are on the upper side of the cable) the cable will pass into the housing but the off-center lances will be on the lefthand side of the cavities as viewed in FIG. 6 and will be against the upper walls of the cavities. Since the shoulders 44 extend only one-half way across the cavities, the ends of the lances will not lodge against the shoulders 44 and the cable will not be retained in the housing. The technician will then immediately realize his mistake and will remove the cable from the housing and reinsert it in its proper orientation.

If it is desired to remove the terminals and cable 14 from the housing 20, a comb-like tool 64 as illustrated in FIG. 8 is employed. This tool has a plurality of spaced-apart pins 66 which are spaced-apart by a distance equal to the spacing between adjacent cavities in the housing and which have a cross-section such that they can be inserted into the terminals in the housing. This tool is inserted into the cavities from the mating side of the housing or insert and is then moved laterally thereby to displace all of the terminals in the housing downwardly against the biasing force of the retention springs 58. The technician, while holding the housing and the extraction tool in one hand then simply grasps the cable 14 with his other hand and pulls it from the housing. Such removal of the cable from the housing is sometimes required to repair a damaged terminal or for inspection purposes.

A significant advantage of the invention is that it is unnecessary to provide clearance in the cavities for an extraction tool as has been common practice in the prior art. As previously noted, clearance is normally provided so that the extraction tool can be inserted into the cavity axially either from the mating side of the housing or from the rearward side. In the past, multi-contact connectors have been designed which do not provide such clearance however, in such connectors it has been necessary to permit access of the extraction tool in a direction laterally of the cavity axis (as shown in U.S. Pat. No. 3,439,314, FIG. 2) and this limitation in turn limits the number of rows of terminals in a particular connector to one or two at the most. Where the connector is constructed in accordance with the instant invention, however any number of rows can be provided. FIG. 9 shows a typical multi-row connector 68 in which lateral access could not be provided for the center row.

A further advantage of the invention is that when an axial pull or tensile pull is imposed on the cable 14, the lances 58, which are relatively delicate, are not stressed. The tensile pull on the cable is rather opposed by the edges 62 of the terminals which are stronger than the lances and can therefore withstand a greater axial force. By virtue of this fact, the terminals are more securely contained in the cavities.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only.

Claims

I claim:

1. A multi-contact electrical connector comprising

an insulating housing having a plurality of contact-receiving cavities extending therethrough from the rearward face thereof to the mating face, each of said cavities having a rectangular cross-section,

each of said cavities having a rearwardly facing shoulder therein which is proximate to said mating face and a forwardly facing shoulder therein which is proximate to said rearward face, said rearwardly facing shoulder being on a first sidewall of said cavity and said forwardly facing shoulder being on the sidewall which is opposite to said first sidewall, said forwardly facing shoulder of each cavity extending only partially thereacross and lying entirely on one side of the axial center line thereof,

electrical contact terminals in said cavities, each of said terminals having a rectangular cross-section conforming to the cross-sections of said cavities and having a forward edge and a rearward edge, said forward and rearward edges being spaced-apart along the length of said contact terminal by a distance which is substantially equal to the distance between said shoulders,

each of said electrical contact terminals having a retention lance extending obliquely and rearwardly from one surface thereof, each retention lance bearing against said first sidewall of its respective cavity and being on the same side of said axial center line as the side of said forwardly facing shoulder, said retention lance biasing said terminal against said opposite sidewall whereby,

said forward edge of said terminal is in engagement with said rearwardly facing shoulder and said rearward edge of said terminal is maintained in engagement with said forwardly facing shoulder thereby to retain said terminal in said cavity.

2. A multi-contact electrical connector comprising:

an insulating housing having a plurality of contact-receiving cavities extending therethrough from the rearward face thereof to the mating face, said cavities having rectangular cross sections,

each of said cavities having a rearwardly facing shoulder therein which is proximate to said mating face and a forwardly facing shoulder therein which is proximate to said rearward face, said rearwardly facing shoulder being on a first side of said cavity and said forwardly facing shoulder being on a second side which is opposite to said first side.

an inclined ramp on said first side of each of said cavities extending towards said rearwardly facing shoulder, and a ledge extending between said rearwardly facing shoulder and the end of said ramp,

said forwardly facing shoulder extending substantially halfway across said cavity,

an electrical contact terminal in each of said cavities, each of said terminals having a forward edge and a rearward edge, said forward and rearward edges being spaced-apart along the length of said terminal by a distance equal to the distance between said shoulders, the forward end of said contact terminal being on said ledge and said forward edge being against said rearwardly facing shoulder,

a resilient lance struck from the body portions of each of said terminals, said lances being on the same sides of the axes of said cavities as said forwardly facing shoulders, said lances being disposed against said first sides of said cavities and biasing said terminals against said second sides whereby,

rearward movement of said terminals is prevented by the engagement of said forwardly facing shoulders with said rearward edges of said terminals and forward movement of said terminals is prevented by the engagement of said forward edges with said rearwardly facing shoulders, said terminals being removable from said cavities upon lateral movement of said terminals and flexure of said springs until said rearward edges are disengaged from said forwardly facing shoulders.

3. A connector housing adapted to receive electrical contact terminals of the type comprising a metallic body having forward and rearward edges and having a laterally extending lance struck from said metallic body, on one side of the axis of said metallic body said housing comprising:

a block of insulating material having a plurality of contact receiving cavities extending therethrough from the rearward face thereof to the mating face thereof, said cavities having a rectangular cross-section,

each of said cavities having a rearwardly facing shoulder proximate to said mating face and a forwardly facing shoulder proximate to said rearward face, said rearwardly facing shoulder being on a first sidewall of said cavity and forwardly facing shoulder being on a second sidewall of said cavity, each of said forwardly facing shoulders extending only partially across its respective cavity and lying entirely on one side of the axial center line of its respective cavity, and

an inclined ramp on said first sidewall of said cavity extending towards said rearwardly facing shoulder and a ledge extending from said rearwardly facing shoulder to the end of said ramp whereby

said cavities are adapted to receive said terminals when said terminals are in an orientation such that the lances are against said first sidewalls of the cavities, and said lances will bias said terminals against said second sidewalls so that said rearward edges of said terminals are against said forwardly facing shoulders and said forward edges are against said rearwardly facing shoulders, said cavities being incapable of receiving said terminals in locking engagement when said terminals are in an orientation such that said lances are on the same sides of said cavities as said first sidewalls.

4. A multi-contact electrical connector as set forth in claim 2 wherein each of said contact terminals is secured to a conductor in a flat conductor cable.