Connector

A male connector 20 includes a male connector housing 22 formed with a multitude of cavities 21, and male terminals 23 mounted in the corresponding cavities 21. A female connector 10 includes a female connector housing 12 and female terminals mounted in the female connector housing 12. A pair of ribs 15 project from the opposite lateral sides of the leading end of the female connector housing 12 to prevent erroneous insertion of the female connector housing. Guide grooves 27 engageable with the ribs 15 are formed in a receptacle 24. Stepped portions 28 are formed on opposed inner wall surfaces of the receptacle 24 in positions higher (more toward the opening edge of the receptacle 24) than the male terminals 23. The obliquely inserted female connector housing 12 comes into contact with the stepped portions 28 and thereby any further entry thereof is blocked.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a connector which establishes connection 
by inserting a female connector housing into a receptacle of a male 
connector housing. 
2. Description of the Prior Art 
The following connector is known as being of the above type. As shown in 
FIGS. 6 and 7, a prior art male connector 1 includes a male connector 
housing 2 having a receptacle 2a and a multitude of male terminals 3 
retained in the male connector housing 2. The terminals 3 project into the 
interior of the receptacle 2a. On the other hand, as shown in FIGS. 8 and 
9, a prior female connector 4 includes a female connector housing 5 which 
is insertable into the receptacle 2a and a multiple of female terminals 
which are to be engaged and connected with the corresponding male 
terminals 3. A pair of ribs 6 project at opposite lateral sides of the 
female connector housing 5 so as to avoid erroneous insertion, and guide 
grooves 7 engageable with the corresponding ribs 6 are formed in the 
receptacle 2a. This arrangement prevents the female connector housing 5 
from being inserted into the receptacle 2a in a wrong direction or 
obliquely as shown in FIG. 8. 
However, even with the ribs 6 formed as described above, if the female 
connector housing 5 is forcibly inserted, the receptacle 2a undergoes 
elastic deformation, thereby allowing entry of the female connector 
housing 5. Then, a corner portion of the female connector housing 5 comes 
into contact with some of the female terminals 3 in the receptacle 2a, 
causing deformation of these terminals 3. As a result, such forcible 
insertion damages the connector. 
In view of the above problem, it is an object of the invention to prevent a 
damage of a connector resulting from wrong insertion of a female connector 
housing. 
SUMMARY OF THE INVENTION 
If the female connector housing in accordance with the subject invention is 
forcibly inserted into the receptacle of the subject invention, it forces 
its entry into the receptacle while causing the receptacle to open wider. 
However, the female connector housing entered into the receptacle comes 
into contact with a stepped portion formed on the inner wall surface of 
the receptacle and thereby its further entry is blocked, with the result 
that contact of the female connector housing with the male terminals can 
be prevented. 
According to a preferred embodiment, when the female connector housing in 
its proper posture is fitted into the receptacle of the male connector 
housing, a rib is engaged with a guide groove formed in the receptacle, 
thereby allowing insertion of the female connector housing. When the 
female connector housing in its reverse or upside-down posture is fitted 
into the receptacle, the rib is not engageable with the guide groove and 
thus the female connector housing cannot be inserted into the receptacle. 
Further, when the female connector housing is obliquely inserted into the 
receptacle, the rib is not in complete engagement with the guide groove. 
Accordingly, unless the posture is corrected, the female connector housing 
cannot be inserted into the receptacle. 
As described above, according to the inventive connector, erroneous 
insertion can be prevented by allowing entry of the female connector 
housing only in its proper posture into the receptacle. Even if the female 
connector housing in its improper posture is forcibly inserted into the 
receptacle, it comes into contact with the stepped portion formed in the 
receptacle and thereby its further entry is blocked. Thus, deformation of 
the male terminals can be securely prevented.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Hereafter, one embodiment according to the invention is described with 
reference to FIGS. 1 to 5. 
A female connector 10 has a known structure including a flat and 
rectangular female connector housing 12 of synthetic resin which is formed 
with a multitude of cavities 11, and female terminals (not shown) 
lockingly mounted in the corresponding cavities 11. The female connector 
housing 12 is unitarily formed in an intermediate portion of one side 
surface thereof with an elastic locking member 14 engageable with an 
engaging claw 26 formed in a male connector housing 22. The locking member 
14 is fixed only at one end at the leading end of the female connector 
housing 10. Further, a pair of ribs 15 project at opposite lateral sides 
of the leading end of the surface where the locking member 14 is formed. 
The ribs 15 act to prevent erroneous insertion of the female connector 
housing 12 into the male connector housing 22 and extend in a forward to 
rearward direction. 
Similar to the female connector 10, the male connector 20 includes a male 
connector housing 22 of synthetic resin which is formed with a multitude 
of cavities 21 and male terminals 23 lockingly mounted in the 
corresponding cavities 21. The male connector 20 is unitarily formed at 
its leading end with a rectangular receptacle 24 into which the female 
connector housing 12 is insertable The receptacle 24 includes an opening 
edge 24a and a rear wall 24b from which the male terminals 23 project. A 
pair of guide ribs 25 project on one inner wall surface of the receptacle 
24 which is to face the locking member 14 of the female connector housing 
12 such that the ribs 25 are located at opposite lateral sides of the 
locking member 14 when the female connector housing 12 is inserted into 
the receptacle 24. An engaging claw 26 (see FIG. 3) that is engageable 
with the locking member 14 of the female connector housing 12 projects 
between the guide ribs 25 and 25. When the female connector housing 12 is 
completely inserted into the receptacle 24, a locking portion 14a of the 
locking member 14 is engaged with the engaging claw 26, with the result 
that female and male connectors 10 and 20 are locked to achieve an 
electrical connection. In order to release the above locking state and to 
detach the connectors 10 and 20 from each other, a pressing portion 14b 
formed at the leading end of the locking member 14 may be pressed so that 
the leading end of the locking member 14 is elastically deformed to move 
closer to the female connector housing 12. 
In the receptacle 24 of the male connector 20, guide grooves 27 along which 
the corresponding ribs 15 are engaged and inserted are formed at the 
opposite lateral sides of the surface where the guide ribs 25 are formed. 
The guide grooves 27 extend straight along the depth direction of the 
receptacle 24. Steps 28 are formed on the inner wall surface of the 
receptacle 24 and parallel to the opening edge 24a of the receptacle 24. 
One step 28 extends continuously between the guide grooves 27. Another 
step 28 extends continuously across an opposed inner wall surface of the 
receptacle 24 opposite the surface on which the guide grooves 27 are 
formed. Each step 28 is located at a specified distance from the rear wall 
24b of the receptacle 24, i.e., in a position higher (more toward the 
opening edge 24a of the receptacle 24) than the leading ends of the male 
terminals 23. The steps 28 are formed such that portions of the receptacle 
24 between the steps 28 and the rear wall 24b define a smaller 
cross-section than portions of the receptacle 24 nearer the opening edge 
24a. Hence, the steps 28 act as projection with which the female connector 
housing 12 obliquely inserted through the opening of the receptacle 24 
comes into contact. It should be appreciated that a distance between these 
opposed inner wall surfaces below the stepped portions 28 (as indicated by 
dimension "a" in FIG. 1 at the bottom part of the receptacle 24) is 
slightly larger than the thickness "b" of the female connector housing 12, 
so that the female connector housing 12 can be inserted to the bottom of 
the receptacle 24 if the connectors 10 and 20 are properly aligned as 
shown in FIG. 1. 
Next, the action of this embodiment is described. When the female connector 
10 is held in a proper posture with respect to the male connector as in 
positional relationship shown in FIG. 1, the ribs 15, 15 are opposed 
straight to the corresponding guide grooves 27, 27 and thus the female 
connector 10 can be readily inserted into the receptacle 24. Thereby, the 
male terminals 23 of the male connector 20 are engaged with the female 
terminals of the female connector 10 and the connectors 10 and 20 are 
connected with each other. 
When the female connector 10 is inverted with respect to the male connector 
20 from the posture shown in FIG. 1, the ribs 15, 15 are not aligned with 
the guide grooves 27, 27. Thus, if an attempt is made to insert the 
inverted female connector 10 into the receptacle 24, the ribs 15, 15 come 
into contact with the opening edge 24a of the receptacle 24 opposite the 
guide grooves 27. Thus of the female connector 10 is impossible and 
erroneous insertion is avoided. 
There are cases where a prior art female connector 10 is obliquely held 
with respect to a prior art receptacle 24 although its vertical posture is 
proper (is not turned upside down) and may be forcibly inserted into the 
receptacle 24. In this case, the receptacle 24 is forced to undergo 
elastic deformation to open wider in prior art connectors. As a result, 
the prior art female connector 10 is inserted deep enough to damage the 
male terminals 23 (see FIG. 9). 
Contrary to the prior art, even if the receptacle 24 of the subject 
invention is forcibly pressed to open wider by the misaligned female 
connector housing 12, the leading end of the female connector housing 12 
comes into contact with the stepped portions 28 formed in the inner wall 
surfaces of the receptacle 24, thereby blocking further entry of the 
female connector housing 12 (FIGS. 4 and 5). Since the stepped portions 28 
are between the opening edge 24a of the receptacle 24 than the male 
terminals 23. Therefore deformation of the male terminals 23 due to 
contact of the female connector housing 12 is not possible. 
According to this embodiment, the female connector housing 12 can be 
inserted into the receptacle 24 only when it is held in a proper posture 
with respect to the receptacle 24. Therefore, erroneous insertion of the 
female connector 10 can be securely prevented. Further, even if the female 
connector housing 12 in its improper posture is forcibly inserted into the 
receptacle 24, it comes into contact with the stepped portions 28 of the 
receptacle 24 and thereby any further entry into the receptacle 24 is 
prevented. Thus, deformation of the male terminals 23 can also be securely 
prevented. 
The invention is not limited to the foregoing embodiment, but may be 
embodied, for example, in the following manners. These embodiments are 
also embraced by the scope of the invention. 
(1) In the foregoing embodiment, a projection is formed by forming the 
stepped portions 28 in the receptacle 24. Instead of the stepped portions 
28, for example, a multitude of ribs extending in the longitudinal 
direction of the male terminals 23 may be formed on the inner wall surface 
of the receptacle 24. These ribs act as projections with which the 
obliquely inserted female connector housing comes into contact. 
(2) In the foregoing embodiment, a multitude of male terminals of identical 
shape are mounted in the receptacle 24. However, for example, large size 
male terminals and small size male terminals can be mixed, e.g., large 
size male terminals having a large conductance may be mounted at opposite 
lateral sides of the receptacle 24 and small size male terminals having a 
small conductance may be mounted in an intermediate portion of the 
receptacle 24.