Electrical connector

An electrical connector for use on tractor-trailer vehicles includes a receptacle and plug. The receptacle housing has a thickened portion and ribs reinforcing the thickened portion to prevent deformation of the receptacle due to vibration of the attached cable. The receptacle housing has an extended body portion to provide a deeper support for an inserted plug. The plug uses non-rotatably mounted bushings to form the female connectors, which bushings are staked, one to another. A cable mounting collar is attached to the plug housing in such a manner that its mounting groove always faces in a downward direction to prevent moisture from passing into the connector plug.

The present invention relates to electrical connectors for use on 
tractor-trailer vehicles. 
One purpose of the invention is a receptacle housing for use in a connector 
of the type described, which housing has a lengthened and reinforced body 
to prevent the plug from falling out and to prevent vibration from the 
weight of the plug and its cable from deforming the receptacle housing. 
Another purpose is an electrical connector having a greater proportional 
engagement between the connector plug and connector receptacle to prevent 
the connector receptacle from deforming. 
A further purpose is an electrical connector having a plug which can be 
inserted an increased distance within the receptacle without a 
corresponding increase of the projection of the receptacle into the 
trailer housing. 
Another purpose is a structure of the type described including 
non-rotatably mounted bushings forming the female contact members in the 
connector plug. 
Another purpose is a connector plug having a mounting collar which fits 
within a groove in the plug housing, which groove is always facing in a 
downward direction, when mounted, so as to prevent moisture from passing 
into the plug interior. 
Other purposes will appear in the ensuing specification, drawings and 
claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
In FIG. 1 a plug is indicated generally at 10 and is positioned for 
insertion within a receptacle 12. Receptacle 12 has a cover 14, pivotally 
mounted, as at 16, which cover is opened when the plug is inserted 
therein. 
Considering the receptacle illustrated in detail in FIG. 1, there is a 
receptacle housing 18 whose open end 20 is closed by cover 14. The 
opposite end of housing 18 is closed by an insert 22 having a plurality of 
contact pins 24 mounted therein. Insert 22 has openings or the like 26 
which receive the contact pins and set screws or the like 28 are used to 
fasten the contact pins to appropriate electrical cable. The inserts are 
retained within the receptacle itself by staking, as at 27. 
With the heavier cable now being used in tractor-trailer vehicle electrical 
systems, the additional weight on the plug has at times caused the plug to 
fall out of the receptacle. Also at times vibration from the vehicle has 
deformed the receptacle wall. This has been due to the excessive weight of 
the cable attached to the rear end of the plug exerting a force on the 
receptacle wall. To reduce this force it was necessary to reduce the 
distance between the cable end of the plug and its fulcrum point at 
opening 20 of the receptacle. Accordingly, cylindrical wall 30 of housing 
18 has been axially lengthened to provide a longer support surface, 
reducing the cantilever extension of the rear end of the plug. 
In providing greater proportional engagement between receptacle and plug by 
lengthening the receptacle wall, it is not desirable that the receptacle 
now protrude a corresponding greater distance into the trailer housing. 
This is because the space of the trailer interior is used for transporting 
cargo. The projection of the receptacle into the trailer not only reduces 
the available space, but exposes the receptacle and its electrical 
connections to possible damage by the shifting or the loading of cargo. 
With this in mind, tubular extension 32 is located forward of outwardly 
extending mounting flange 36, so that a greater engagement between 
receptacle and plug is accomplished without increasing the projection of 
the receptacle into the trailer interior. It has been found that this is 
best accomplished by tubular extension 32 being of a length approximately 
equal to 1/4 to 1/2 of the overall length of the now-extended receptacle. 
A shorter extension does not provide sufficient support to prevent the 
receptacle wall from deforming. While a longer extension does not prevent 
deformation of the receptacle, it places too great a stress on the trailer 
body to adequately support the overhanging receptacle, plug and cable. 
Additional steps have been taken to prevent the receptacle from deforming. 
There is a thickened portion at tubular extension 32 of cylindrical wall 
30 which provides greater reinforcement adjacent the open end 20 which 
receives the plug, and there may be a plurality, for example three, ribs 
34 which are integral with housing 18 and with mounting flange 36. Note 
particularly FIG. 2. Flange 36 may have conventional openings 38 for use 
in attaching the receptacle to the vehicle body. 
Turning to the plug, as illustrated in FIGS. 1, 3 and 4, there is a plug 
housing 40, generally cylindrical in form, and having an exterior axially 
extending key 42 which fits within a mating groove 44 in the interior of 
receptacle housing 18. Key 42 has an outwardly-extending projection 46 
which cooperates with member 48 on the cover 14 to interlock the plug 
within the receptacle when the two are assembled together. Key 42 and 
groove 44 are particularly arranged to align the plug and receptacle 
relative to the mating electrical contacts. 
A collar 50 is positioned within a radially extending groove 52 at one end 
of housing 40. Collar 50 has an opening 54 in one side thereof for use in 
hanging the collar and thus the plug upon a convenient portion of the 
vehicle body. 
Of particular importance is the fact that groove 52 faces in a downward 
direction, as shown in the drawings, or to the side opposite that of key 
42. In practice, the receptacle and plug are arranged so that the key on 
the plug and the mating groove on the receptacle face in an upward 
direction. Thus, groove 52 will always face downward, which will prevent 
any moisture which might pass along the sides of the groove from reaching 
the interior of the plug housing. The primary purpose of collar 50 is to 
attach the cable to the plug. Screws 56 are threaded into mating bosses in 
the plug housing so as to tighten the collar upon the cable position 
within the plug. Collar 50 also provides a hand grip with opening 54 being 
used to mount the plug as described. 
An insert 60 is positioned in open end 62 of housing 42 and is generally 
cylindrical in form. There are a plurality of axially extending passages 
64 in insert 60, which passages mount the female contacts which will mate 
with contact pins 24 in the receptacle. Each passage 64 includes a first 
portion 66, an intermediate key 68 and a second portion 70, hex-shaped in 
cross section, and slightly larger in diameter than portion 66. A 
hex-shaped bushing 72 is positioned within hex-shaped passage portion 70 
providing a non-rotatable mounting for the bushing. An elongated bushing 
74, shown in detail in FIG. 5, is positioned within passages portion 66 
and itself has a reduced diameter portion 76 which fits within hex-shaped 
bushing 72. Bushing 74 may have an axially extending slot 78 formed when 
the bushing is rolled from flat stock. Slot 78 will be aligned with key 68 
when the bushing is inserted from one end of insert 60 to the position 
shown in FIG. 4. Thus, the combination of key 68 and slot 78 provides a 
non-rotatable mounting for bushing 74. Bushing 74 may further have an 
axially extending slot 80 which provides for flexibility of the bushing to 
accomodate insertion of contact pins 24. 
After bushing 74 has first been inserted in insert 60, bushing 72 is then 
positioned outside of bushing portion 76 and within hex-shaped passage 
portion 70. A mechanical staking of bushing portion 76 to bushing 72 then 
takes place at the co-extensive ends, as indicated at 82, in FIG. 1. Thus, 
the two bushings are mechanically fastened together. 
The passage and bushing combinations described above relate to those female 
contacts of the plug with the exception of the center contact and one 
peripheral contact. Again, looking particularly at FIG. 1 in the center 
contact, bushing 84 and bushing 86 are the same as described above, except 
that bushing 84 has a portion 88 of greater axial extent than bushing 
portion 76. In this case, hex-shaped bushing 86 is not recessed to the 
same depth as bushings 72 described above. In other respects the 
construction is the same. In all cases there are set screws 90 which are 
used to fasten the electrical wires to the bushings. 
Of particular advantage in the bushing structure shown is the fact that the 
bushings forming the female electrical contacts are non-rotatable relative 
to the housing insert permitting drilling and tapping of the bushings 
after they have been positioned. Also, there is correct alignment between 
the bushings and the insert providing for uniformity of the overall 
structure. 
Whereas the preferred form of the invention has been shown and described 
herein, it should be realized that there may be many modifications, 
substitutions and alterations thereto.