Terminal locking means for electrical connectors

An electrical connector is disclosed with a dielectric housing having a through passage for receiving a female terminal which includes a terminating end for engaging a conductor and a mating end for receiving a male terminal. A resilient locking arm is formed on the housing and is adapted to engage a locking surface on the female terminal for locking the female terminal in the passage. The locking arm is located for engagement by the male terminal upon entering the passage to prevent the locking arm from disengagement with the locking surface.

FIELD OF THE INVENTION 
This invention generally relates to the art of electrical connectors and, 
particularly, to an electrical connector which has locking means for 
locking terminals in the connector housing. 
BACKGROUND OF THE INVENTION 
There are many electrical connectors available of a type having a locking 
mechanism by which male or female terminals of the connector are locked in 
a connector housing. The locking mechanism defines a fully inserted 
position of a terminal and prevents the terminal from backing out of a 
dielectric connector housing opposite its direction of insertion. Many 
such locking mechanisms are provided in the form of resilient latch arms 
which lockingly engage the terminals. Often, the resilient latch arms are 
integrally molded with the dielectric housing for pivoting in a 
cantilevered fashion. An example of such a locking mechanism is shown in 
U.S. Pat. No. 4,319,797 to Otani et al, dated Mar. 16, 1982. 
Problems with locking mechanisms of the character described above are 
becoming increasingly prevalent due the ever-increasing miniaturization of 
electrical connectors and their respective housings and terminals. In 
fact, the miniaturization of such electrical connectors has reached a 
point where such locking mechanisms hardly resist even moderate pull out 
forces on the respective terminals. This invention is directed to solving 
such problems by providing a locking means or system which can withstand 
relatively high pullout forces on the terminals which are locked within 
the connector housing. 
SUMMARY OF THE INVENTION 
An object, therefore, of the invention is to provide a new and improved 
locking system for terminals in an electrical connector. 
In the exemplary embodiment of the invention, an electrical connector is 
disclosed to include a dielectric housing having a through passage for 
receiving a first terminal including a mating section for mating with a 
second terminal. Generally, locking means are provided on the housing and 
adapted to engage a locking surface on the first terminal for locking the 
first terminal in the housing. The locking means is located for engagement 
by the second terminal upon mating with the first terminal to prevent the 
locking means from disengagement with the locking surface. 
As disclosed in the preferred embodiment, the locking means is provided in 
the form of a resilient locking arm integrally molded with the dielectric 
housing and adapted to engage a recess in a female terminal for locking 
the female terminal in the housing passage. The female terminal is 
provided with a socket at its mating end for receiving a male or pin 
terminal. The socket has a side wall provided with the recess which 
lockingly engages the resilient locking arm. The arm projects through an 
open mating end of the socket. When the male terminal or pin is inserted 
into the socket, it engages the locking arm to sandwich the locking arm 
between the male terminal and the side wall of the socket, thereby 
preventing the locking arm from lifting out of the recess. 
Other objects, features and advantages of the invention will be apparent 
from the following detailed description taken in connection with the 
accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings in greater detail, and first to FIGS. 1 and 2, an 
electrical connector, generally designated 10, is illustrated to include a 
dielectric housing, generally designated 12, and a pair of female 
terminals, generally designated 14. Although the illustration shows an 
electrical connector having a pair of terminals, it should be understood 
that the invention is applicable for any type of electrical connector of 
the character described herein regardless of the number of terminals 
employed by the connector. 
Referring to FIG. 3 in conjunction with FIGS. 1 and 2, housing 12 of 
electrical connector 10 includes a unitary housing 16 molded of dielectric 
material such as plastic or the like and including a through passage 18 
for receiving each terminal 14. Each terminal is inserted into its 
respective passage in the direction of arrow "A" (FIG. 3). Each passage 18 
includes a chamfered open end or mouth 20 at the mating end of housing 16 
and through which a male terminal or pin is inserted in the direction of 
arrow "B" (FIG. 3) for mating with the respective terminal 14. Lastly, 
locking means in the form of a resilient locking arm 22 is integrally 
molded with housing 16 and projects rearwardly into passage 18 from open 
mouth 20 of the passage. 
At this point, it should be noted that a bottom surface 24 of locking arm 
22 is spaced above the bottom of passage 18 as can be seen clearly in FIG. 
3. The locking arm has a hook portion 26 defining a forwardly facing 
locking shoulder 28. The bottom wall of the housing has an opening 30 to 
accommodate the projecting hook portion of the locking arm. 
Referring to FIGS. 4 and 5 in conjunction with FIGS. 1 and 2, each terminal 
14 is a female terminal having a rear terminating end 32 and a front 
mating end 34. The terminal is unitarily formed as by stamping and forming 
from sheet metal material. The terminal has a pair of insulation 
displacement sections 36 stamped and formed upwardly out of a bottom wall 
38 of the terminal. The insulation displacement sections have notches 40, 
the edges of the notches being designed to pierce through the insulation 
of an insulated wire and establish conductivity with the conductor core of 
the wire. A pair of crimp arms 42 are provided at the rear distal end of 
the terminal for clamping onto the outside of the insulated wire. 
Each terminal 14 is generally U-shaped in cross section, and mating end 34 
includes a pair of side walls 44 upstanding from bottom wall 38. The side 
walls are formed inwardly to define opposing dimples 46 which define a 
gap, as indicated at 48 in FIG. 4, for receiving a male terminal or pin 
therebetween. In essence, bottom wall 38 and side walls 44 define a socket 
for the terminal, with the socket having an open mating end 50 (FIG. 4) 
for receiving the male terminal or pin. 
FIG. 6 shows, somewhat schematically, a male terminal or pin 52 inserted 
into the socket defined by mating end 34 of the terminal, the male 
terminal being inserted between side walls 44. Lastly, bottom wall 38 of 
mating end 34 of the terminal has a rearwardly facing edge 54 which 
defines a recess or a locking surface for cooperating with hooked latch 
arm 22 to lock the terminal in its passage 18 of connector housing 16, as 
described below. 
When one of the terminals 14 is inserted into its respective passage 18 in 
connector housing 16 in the direction of arrow "A" (FIG. 3), the forward 
edge of bottom wall 38 of mating end 34 of the terminal engages a 
rearwardly facing chamfered surface 60 (FIG. 3) of hook portion 26 of 
locking arm 22. Consequently, the locking arm will be biased upwardly in 
the direction of arrow "C" (FIG. 3), whereupon further insertion of the 
terminal will cause rear edge or locking surface 54 (FIGS. 4 and 5) of the 
locking surface to move past locking shoulder 28 of the latch arm. The 
latch arm will snap back downwardly, under its own resiliency, whereupon 
hook portion 26 will move into the recessed area of the terminal behind 
locking surface 54 and lock the terminal within the housing by engagement 
of locking shoulder 28 on the locking arm and locking surface 54 defined 
by bottom wall 38 of the terminal. 
Theoretically, when the terminal is fully inserted into the housing as 
described immediately above, pulling forces on the terminal, as by pulling 
on an insulated wire terminated to the terminal in a direction opposite 
arrow "A" (FIG. 3), will prevent the terminal from being pulled out of 
locking interengagement of locking shoulder 28 on the locking arm and 
locking surface 54 on the terminal. However, with the ever-increasing 
miniaturization of electrical connectors, the locking arm has difficulty 
resisting such pull-out forces. 
The invention solves these problems by the structural combination described 
above and as explained hereinafter. More particularly, FIG. 7 is a view 
similar to that of FIG. 6, except that the location of locking arm 22 is 
shown within the mating end 34 of terminal 14, and in relation to an 
inserted or mated male terminal or pin 52. It can be seen that, upon 
insertion of the male pin into the housing passage and between side walls 
44 of the mating end of the terminal, the locking arm is located 
immediately below the male terminal or pin. Consequently, when any pull 
out forces on female terminal 14 in a direction opposite arrow "A" (FIG. 
3), which would tend to bend locking arm 22 upwardly and release the 
locking engagement of the arm, the terminal pin provides a supporting 
backing against the top of the locking arm to prevent or at least resist 
disengagement of locking shoulder 28 on the locking arm from locking 
surface 54 on bottom wall 38 of the terminal. Of course, it can be 
imagined that an extremely large pull out force could cause the terminal 
to be pulled out of the connector regardless of any provision of any 
locking means and, in essence, destroy the entire connector. However, 
under normally expected conditions, the location of the locking arm, so as 
to be backed-up by the more rigid metal terminal pin, essentially prevents 
the locking arm from disengagement from the terminal. In essence, the 
resilient locking arm is sandwiched between the metallic bottom wall 38 of 
the terminal at the mating end thereof and the metallic male pin. 
It will be understood that the invention may be embodied in other specific 
forms without departing from the spirit or central characteristics 
thereof. The present examples and embodiments, therefore, are to be 
considered in all respects as illustrative and not restrictive, and the 
invention is not to be limited to the details given herein.