Double-lock electrical connector

An electrical connector (20,60) includes rows of chambers (36) into which contacts (26) are held seated in place in such chambers through internal lances (58) and a double-locking device (24) inserted through an opening (40) in a wall of the housing (22) of the connector. The locking device (24) includes latches (52) which cooperatively engage depressions (50) to establish a first locking position allowing contact insertion and further latches (56) which engage interior walls (54) to establish a second locking position upon final insertion of the device (24) into the housing (22). Improper contact insertion and seating precludes operation of the locking device (24) as a visible indication of improper insertion. Proper insertion of locking device (24) assures a double-locking against contact backout and provides primary and secondary retention of contacts in the connector.

This invention relates to an electrical connector including a double-lock 
to prevent contact backout. 
BACKGROUND OF THE INVENTION 
Electrical connectors designed to provide a reliable and secure contact 
retention, to preclude contact backout of connector housings are in wide 
use at this time. Such uses include particularly vehicular electrical 
systems where vibration and road shocks have been known to cause contact 
backout and electrical system failure. The prior devices typically include 
insulating housings equipped with lances protruding from the internal 
walls of the housing into the contact receiving chambers and additionally 
a double-lock device made of plastic which is inserted through a side wall 
of the housing to block contact backout. An example of a double-lock prior 
art publication wherein the locking operates by engaging the rear end of a 
contact may be found in Japanese publication No. HEI 1 (1989)-43986. An 
alternative retention of contacts is taught in Japanese publication No. 
HEI 1 (1989)-64872, wherein the insulating housing is arranged to clamp 
the contacts. 
In yet a further alternative as taught in Japanese publication SHO64 
(1989)-54678 and depicted as prior art in FIGS. 6 and 7 of this 
application, a double-lock device 13 is inserted into a wall la of an 
insulating housing 1. The double-lock device 15 has member 13 and 
projections 8 which fit into openings 6 of housing 1. Retention lugs 9 are 
on member 13 and lugs 10 are on the projections 8 and member 13, as shown 
in FIG. 6. Projections 10 fit within notches in a contact 3 in the side 
thereof and preclude withdrawal of the contacts or displacement and 
backout. Lugs 9, 9' latch device 15 into housing 1 as shown in FIG. 7. As 
also shown in FIG. 7 the referred to prior art contact 3 includes a latch 
5 which latches internally of the housing and is one part of the 
double-lock system of retention. 
Problems with prior art double-lock devices such as those referred to 
include tolerance variations in housings and contacts which result in an 
incomplete insertion of the contacts which can allow backout despite the 
double-lock features. Another problem relates to the use of spring 
elements on contacts which may be deflected inelastically to preclude 
functioning in holding the contacts in position during the insertion of 
double-lock devices in the housing. With respect to multi-way connectors, 
the need to fully insert all contacts prior to insertion of the 
double-locking device may be frustrated if a single contact is not fully 
seated. Still a further problem has to do with connectors which require 
more than two rows of chambers and contacts and particularly with those 
wherein the chambers and contacts are required to be staggered for the 
purposes of improved density or layout considerations. 
Accordingly it is an object of the present invention to provide an 
electrical connector having double-lock features precluding contact 
backout which relate to improved reliability, ease of use and adaptation 
to connectors having more than two rows of chambers and contacts. It is 
still a further object to provide a double-locking electrical connector 
which allows the locking device to be retained in the connector prior to 
and during insertion of contacts and then activated further to effect the 
double-locking function. 
SUMMARY OF THE INVENTION 
The present invention achieves the foregoing objectives by the provision of 
an insulating housing with a number of chambers extending through the 
housing to receive a number of contacts inserted therein and with an 
opening in a wall of the housing extending across the housing and 
intersecting the chambers and paths of insertion of the contacts. The 
invention includes a double-lock device in the form of a plastic element 
having apertures and reliefs therein which can be inserted in the opening 
in a first position of alignment allowing insertion of contacts into the 
housing and through the locking device and a second position wherein edge 
surfaces of the locking device engage edge surfaces of contacts to 
preclude contact backout. The housing includes plastic latch elements 
internally which engage the contacts and provide a primary retention 
holding the contacts in place in the housing and the double-lock device 
when activated serves as a secondary retention against contact backout. 
The locking device includes projections which engage interior surfaces of 
the housing to provide the first and second positions in the opening of 
the housing to allow contact insertion and provide secondary retention. 
The contacts of the invention include rigid edge surfaces which are 
engaged by edge surfaces of the locking device to minimize problems with 
tolerance variation or inelastic deformation of spring elements and the 
like.

DETAILED DESCRIPTION OF THE INVENTION 
FIGS. 1 and 2 represent perspective exploded views from two directions, 
upper and lower, of an embodiment of an electrical connector of the 
double-lock type in accordance with the present invention. The elements 
are shown disassembled. As can be discerned from these figures a connector 
20 consists of an insulating housing 22, a double-lock device 24 and a 
contact 26 which is representative of the multiple contacts accommodated 
by housing 22. FIG. 1 shows the contact insertion side 28 of housing 22 
and a number of openings 30 into which contacts 26 are inserted. FIG. 2 
shows the reverse side 32 of housing 22 with a series of openings 34. The 
connector housing 22 is adapted to mate with a matching connector half not 
shown in the figures, the openings 34 adapted to receive contacts which 
mate with contacts 26 inside the housing 22. As can be discerned both sets 
of openings 30 and 34 are arranged in two rows. The openings 30 and 34 
lead to contact receiving chambers 36 in which the contacts 26 are fitted 
in the manner shown FIGS. 3 and 4. The side of housing 22, side 38, is 
shown in FIG. 2 to include a large opening 40 which accommodates the 
double-lock device 24 inserted therewithin. The opening 40 is made in such 
a way that it intersects the contact receiving chambers 36. The 
double-lock device 24 is typically made of a synthetic plastic resin, of 
insulating characteristics. It has a continuous base 42 in its 
longitudinal direction, from which extend partitions 44 which are spaced 
out at certain intervals. The ends of the partitions 44 are connected to 
portions 46 which are interconnected in turn, so as to form the contact 
openings 48, arranged in a single row. 
In a prelocked position of the double-lock device 24 as shown in FIG. 3, 
the contact openings 48 line up with the lower row of the contact 
receiving chambers 36 of the insulating housing 22. At both ends of the 
base 42 of the double-lock device 24 are lugs or projections 52 which can 
be seen in FIGS. 1 and 2. These projections serve to provide a first 
locking step during insertion of the locking device 24 through engagement 
of projections 52 with depressions 50 in housing 22, one of which is shown 
in FIG. 2. On the back end of base 42 are provided stopping lugs or 
projections 56 of the second locking step, which lock into the internal 
wall 54 of the contact receiving chambers 36 of the housing 22, as shown 
in FIG. 4. 
FIG. 3 shows in cross-section the double-lock device 24 inserted in the 
first locking step position allowing insertion of contacts 26 through the 
alignment heretofore mentioned with the chambers 36. The locking device 24 
is held temporarily attached to housing 22 due to the fact that the 
projections 52 of the first locking step are engaged in the depressions 50 
as mentioned. As the contacts are inserted from the position shown in FIG. 
3 to the position shown in FIG. 4 lances 58 formed internally of the 
housing and extending into the chambers engage a notch 26a of the contacts 
26 in the manner shown in FIG. 4 to latch the contacts forwardly. It is to 
be understood that until such contacts are seated and the latches 58 are 
so engaged in notches 26a of contacts 26 the locking device 24 cannot be 
fully engaged. Thus in the position of the contact 26 shown in FIG. 3 it 
will be discerned that the leading left edge of device 24 will strike the 
bottom surface 26b of contact 26 and preclude full insertion of the device 
24. 
The lances 58 serve the primary retention feature for the connector 20 and 
by driving the contacts home to the point of latching the connector can 
then be manipulated to insert the device 24 without fear that the contact 
will become loose and back out. Additionally, as mentioned above, the 
device 24 cannot be actuated until the contacts are fully seated. 
After all contacts 26 are secured in the connector with the lances 58 in 
place, the double-lock device 24 is pushed further into the opening 40 
where it assumes the position shown in FIG. 4. There the projections 56 of 
the second locking step engage the internal wall 54 of the lower row of 
contact receiving chambers 26 of housing 22 and secure the double-lock 
device 24 in the position shown in housing 22. In this condition the edges 
60, 60' of the front end of the double-lock device 24, referring to FIGS. 
2-4, are pressed against the back edges of the lower surfaces 26b of the 
contacts 26 to add a second retention and form the second locking step of 
the connector. The portions 46 of double-lock device 24 are part of a 
solid piece of plastic material as shown in FIGS. 1 and 2 and cannot be 
readily bent as in the case with the conventional projections in the prior 
art heretofore mentioned. This will cause a stubbing of portion 46 against 
the surface of an incompletely inserted contact as mentioned to assume a 
positive and readily identified recognition of incompletely inserted 
contacts. 
Should removal of the double-lock device 24 be desired a screwdriver 
pressed into the opening 56a situated next to the projection 56 will allow 
deflection of the plastic parts and removal of the locking device from the 
position shown in FIG. 4 to the position shown in FIG. 3 and, thereafter, 
allow removal of the contacts by manipulating the lances 58 through the 
front openings 34 with a screwdriver or other blade tool. The invention 
contemplates a second locking step which is not limited to an engagement 
of the back end of the contact but rather against any back surface of the 
contact or in other locations which do not lead to a variation in the 
dimensions after locking has taken place. 
FIG. 5 is a view of an alternative embodiment of the double-lock electrical 
connector in accordance with the invention. In FIG. 5 a connector 60 of an 
alternative construction is shown to have a housing 62 containing openings 
64 through which contacts of a matching connector half (not shown) are 
inserted. The openings 64 are arranged in a four row and zig-zag pattern 
and join contact receiving chambers not shown but essentially similar to 
those shown with respect to FIGS. 1-4. A double-locking device 66 is 
included which has openings 68 for contacts to pass through and these 
openings correspond to three of the rows of contact insertion opening 64 
and are also arranged in a matching zig-zag pattern. The double-locking 
device 66 is inserted into housing 62 through an opening not shown but 
arranged across the housing 62 in the manner described with respect to the 
previous embodiment. As can be appreciated with respect to prior art 
double-lock devices like that shown in FIGS. 6 and 7 an arrangement of 
rows of apertures which are staggered or in a zig-zag pattern could not be 
readily done with the locking device shown in FIG. 6. 
Having now described the invention in terms intended to enable a preferred 
practice thereof claims are appended and intended to define the invention;