Short-circuiting terminal fitting and connector therefor

A short-circuit terminal fitting 30 is provided with a protection wall 35 to prevent deformation of elastic contact portions due to interference by other members and to prevent excessive deformation of the elastic contact portions due to an excessive pressing displacement of a lock arm. The protection wall 35 is so formed as to surround the leading free ends of elastic contact portions 32 which are fixed at one end thereof and hanging at the other end thereof. When the short-circuiting terminal fitting 30 is handled alone, the elastic contact portions 32 are unlikely to be interfered with by other members since they are surrounded by the protection wall 35 and, accordingly, the deformation of the elastic contact portions 32 due to interference by other members can be prevented. Further, the protection wall 35 prevents deformation of the elastic contact portions 32 that otherwise could be caused by a lock arm 21 engaging the elastic contact portion 32 when the fitting 30 is mounted in a female connector housing 20.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a short-circuiting terminal fitting for 
detecting an engaged state of a connector and a connector provided with an 
engagement detecting function comprising such a short-circuit terminal 
fitting. 
2. Description of the Prior Art 
A known connector provided with an engagement detecting function is 
disclosed in Japanese Unexamined Patent Publication No. 7-201414. This 
connector is constructed, as shown in FIG. 8, such that a connector 
housing 1 is provided with a lock arm 2 and a short-circuiting terminal 
fitting 3 provided with elastic contact portions 4 is mounted in the 
connector housing 1. When this connector is partly engaged with a mating 
connector housing 5, as shown in FIG. 8, a projection 6 formed on the lock 
arm 2 is in contact with an engaging portion 7 of the mating connector 
housing 5, thereby being elastically deformed downward. The elastic 
contact portions 4 pressed by the lock arm 2 are displaced to positions 
where they are not in contact with a pair of detection terminals 8 
provided in the mating connector housing 5. In this state, since the 
detection terminals 8 are not short-circuited, the partial engagement of 
the connector housings 1, 5 is detected. Further, when the connector 
housing 1 is properly engaged with the mating connector housing 5, the 
projection 6 having passed the engaging portion 7 is lockingly engaged 
with the edge of the engaging portion 7 by the elastic restoring force of 
the lock arm 2 and, not being pressed by the lock arm 2 any longer, the 
elastic contact portions 4 elastically return to their original upper 
positions to contact and short-circuit the detection terminals 8. As a 
result, the proper engagement of the connector housings 1, 5 is detected. 
As shown in FIG. 9, the elastic contact portions 4 of the short-circuiting 
terminal fitting 3 are fixed at one end thereof and hanging or deflectable 
at the other end thereof in order to facilitate its elastic deformation. 
Thus, when the short-circuiting terminal fitting 3 is handled alone, the 
elastic contact portions 4 may come into contact with and/or get caught 
with other members or elastic contact portions 4 of another 
short-circuiting terminal fitting 3. This may cause the deformation of the 
elastic contact portion 4. Further, when the short-circuiting terminal 
fitting 3 is mounted in the connector housing 1, the elastic contact 
portions 4 project into a space for the insertion of the short-circuiting 
terminal fitting 3 which is open in the rear end surface of the connector 
housing 1. Accordingly, if a foreign matter or the like enters this space, 
the elastic contact portions 4 may be deformed. Furthermore, if, due to a 
contact with a foreign matter or other reason, the lock arm 2 is 
excessively deformed beyond its usual degree of displacement when the 
connector housings 1, 5 are partly engaged, the elastic contact portions 4 
may be excessively deformed beyond their elasticity limit. 
The present invention was developed in view of the above problems and an 
object thereof is to prevent the deformation of an elastic contact portion 
due to the interference by other member(s) and an excessive deformation of 
the elastic contact portion due to an excessive pressing displacement of a 
lock arm. 
SUMMARY OF THE INVENTION 
According to the invention, there is provided a short-circuiting terminal 
fitting which is mountable in one of a pair of connector housings. The 
short-circuiting terminal is provided with an elastic contact portion 
which is deflectable at an end thereof by a deflection means provided in 
one connector housing. The elastic contact portion can be brought out of 
contact with at least a pair of detection terminals by being deflected by 
the deflection means when the pair of connector housings are partly 
engaged. The elastic contact portion can short-circuit the detection 
terminals by being released from the deflection by the deflection means 
and by coming into contact with the detection terminals when the connector 
housings are properly engaged. Thus an engaged state of the pair of 
connector housings can be detected based on a short-circuited state of the 
detection terminals. 
A protection wall is provided substantially around the deflectable or 
hanging end of the elastic contact portion. Since the elastic contact 
portion is surrounded by the protection wall, it is unlikely to be 
interfered by other member(s) and, accordingly, its deformation due to the 
interference by the other member(s) can be prevented. 
According to a preferred embodiment of the invention, the deflection means 
comprises a lock arm, which locks the pair of connector housings in their 
engaged state, wherein the elastic contact portion is operable together 
with the lock arm and is deflected by being pressed by the lock arm. 
Preferably, the protection wall prevents an excessive deformation of the 
elastic contact portion by being brought into contact with the deflection 
means, in particular the lock arm, when the deflection means is moved, in 
particular the lock arm is pressingly displaced. Thus the protection wall 
forms deflection limiting means. 
Further preferably, the elastic contact portion is folded back from one end 
of a substantially flat platelike base portion toward the other end 
thereof, and the protection wall stands at substantially the periphery of 
the other end of the base portion. 
The deflection means, in particular the lock arm, may comprise an 
inclination or displacement preventing portion for preventing an 
inclination or displacement of the deflection means along a coupling or 
insertion direction of the connector housings and/or in a direction 
substantially normal to the coupling direction of the connector housings 
by coming into contact with the protection wall. The inclination 
preventing portion preferably comprises a step and/or a recess provided in 
the deflection means, in particular in the lock arm. 
Accordingly the deflection means, in particular the lock arm, cannot be 
further displaced, when the deflection means reaches the protection wall, 
due to the wedging or locking with the inclination preventing portion. 
Thus an excessive deformation of elastic contact portions due to the 
pressing displacement of the deflection means, in particular of a lock arm 
is prevented 
Most preferably, a deflectable or distal end of the elastic contact portion 
comprises a rear bent surface obliquely inclined such that a force 
generated by a member other than the deflection means contacting the 
deflectable end from behind with respect to a coupling direction of the 
connector housings, is diverted. 
According to the invention, there is further provided a connector with an 
engagement detecting function, comprising at least a pair of connector 
housings that are engageable with each other. At least a pair of detection 
terminals are provided in one housing. A short-circuit terminal fitting, 
is provided with an elastic contact portion which is fixed at one end 
thereof and hanging or deflectable at the other end thereof by a 
deflection means provided in one connector housing. The short-circuit 
terminal is brought out of contact with the detection terminals by the 
elastic contact portion being deflected by the deflection means when the 
pair of connector housings are partly engaged and short-circuits the 
detection terminals by the elastic contact portion released from the 
deflection by the deflection means and coming into contact with the 
detection terminals when the connector housings are properly engaged, so 
that an engaged state of the pair of connector housings can be detected 
based on a short-circuited state of the detection terminals, wherein a 
protection wall is provided substantially around the leading or 
deflectable end of the elastic contact portion. 
According to a preferred embodiment, the detection terminals are supported 
in one connector housing and reinforced by a rib projecting from the 
connector housing and arranged along at least a portion of the detection 
terminals. 
Preferably, the deflection means of the one connector housing comprises a 
lock arm capable of interacting with a lock projection or recess of the 
other connector housing and locking the connector housings in their 
engaged state, wherein the lock arm is preferably deflectable or 
deformable in a deformation permitting space provided in the one connector 
housing. 
According to a further preferred embodiment, there is provided a 
short-circuiting terminal fitting which is mountable in one of a pair of 
connector housings to be locked in their engaged state by a lock arm; is 
provided with an elastic contact portion which is operable together with 
the lock arm, fixed at one end thereof and hanging at the other end 
thereof; is brought out of contact with a pair of detection terminals by 
the elastic contact portion being pressed by the lock arm when the pair of 
connector housings are partly engaged and short-circuits the detection 
terminals by the elastic contact portion released from the pressing by the 
lock arm and coming into contact with the detection terminals when the 
connector housings are properly engaged so that an engaged state of the 
pair of connector housings can be detected based on a short-circuited 
state of the detection terminals, wherein a protection wall is provided 
around the leading end of the elastic contact portion. 
Preferably, the protection wall prevents an excessive deformation of the 
elastic contact portion by being brought into contact with the lock arm 
when the lock arm is pressingly displaced. 
Accordingly, if the lock arm is excessively pressingly displaced beyond its 
usual degree of displacement while the short-circuiting terminal fitting 
is mounted in the connector housing, any further deformation of the lock 
arm is prevented by being brought into contact with the protection wall. 
Thus, an excessive deformation of the elastic contact portion can be 
prevented. 
Most preferably, the elastic contact portion is folded back from one end of 
a flat platelike base portion toward the other end thereof and the 
protection wall stands at the periphery of the other end of the base 
portion. 
Accordingly, since the protection wall stands on the base portion, the 
strength of the protection is higher as compared with a case where the 
protection wall is fixed at one end and hanging at the other end. Further, 
since the base portion is flat platelike, when the short-circuiting 
terminal fitting is inserted into a receptacle therefor, it can be held in 
a stable configuration by sliding the base portion along an inner wall of 
the receptacle. Accordingly, the short-circuiting terminal fitting can be 
easily inserted. 
These and other objects, features and advantages of the present invention 
will become more apparent upon a reading of the following detailed 
description and accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to FIGS. 1 to 6, a connector housing 10 for a circuit board 
which is formed with a hood 11 having an open front surface. A plurality 
of preferably L-shaped terminals 12 are so mounted that their leading ends 
project into the hood 11. Two terminals 12 located in uppermost positions 
in the hood 11 act as detection terminals 13 which enable short-circuiting 
by a short-circuiting terminal fitting 30 to be described later. These 
detection terminals 13 are reinforced by a rib 14 arranged along the upper 
surfaces thereof. On the upper wall of the hood 11 is formed a lock 
portion 15 to be engaged with a lock arm 21 of a female connector housing 
20 to be described later. 
The female connector housing 20 is fittable or insertable into the 
connector housing 10. The female connector housing 20 is formed with the 
lock arm 21 which is folded back at an upper edge of the front end surface 
of the female connector housing 20 to extend rearwardly. This lock arm 21 
is inserted along the upper wall of the hood 11 when the connector 
housings 10 and 20 are engaged. On the upper surface of the lock arm 21 is 
formed a projection 22 engageable with the lock portion 15 of the hood 11. 
In a partly engaged state of the connector housings 10, 20 immediately 
before they are properly engaged, the projection 22 engages the lower 
surface of the lock portion 15, thereby elastically deforming the lock arm 
21 downwardly. When the connector housings 10, 20 are properly engaged, as 
shown in FIG. 3, the projection 22 passes the lower surface of the lock 
portion 15, with the result that the lock arm 21 returns to its original 
upper position due to its elastic restoring force and the projection 22 is 
engaged with the rear surface (left surface in FIG. 3) of the lock portion 
15. The connector housings 10, 20 are locked in their properly engaged 
state by this engagement of the projection 22 and the lock portion 15. 
When the lock arm 21 is deformed downwardly by pressing an operable 
portion 23 at the leading end of the lock arm 21, the projection 22 is 
disengaged from the lock portion 15, thereby permitting the disengagement 
of the connector housings 10, 20. 
Below the lock arm 21 is formed a receiving space 24 for receiving the 
detection terminals 13 of the connector housing 10. The receiving space 24 
is partitioned from a deformation permitting space 26 of the lock arm 21 
by a partition wall 25 that extends approximately 2/3 of the length of the 
lock arm 21 from the base end of the lock arm 21 (front end of the female 
connector housing 20 with respect to a coupling or insertion direction A 
of the connector housings 10, 20; FIG. 1) toward the leading end thereof 
(rear end of the female connector housing 20 with respect to the coupling 
direction A). A space before the receiving space 24 is a communication 
space 27 which communicates with the rear end surface of the female 
connector housing 20 and the deformation permitting space 26 of the lock 
arm 21. 
Below the receiving space 24 is provided a terminal receptacle 28 for 
holding and accommodating the short-circuiting terminal fitting 30. The 
terminal receptacle 28 extends substantially over the entire length of the 
female connector housing 20 from its front end to its rear end, and 
communicates with the receiving space 24 and the communication space 27. 
The terminal receptacle 28 has a substantially flat lower surface, and a 
fitting portion 29, into which the short-circuiting terminal fitting 30 is 
fitted, is formed at a front end thereof. 
The short-circuiting terminal fitting 30 is particularly formed by bending 
a conductive metal plate which is punched into a specified shape. The 
short-circuiting terminal fitting 30 has a substantially flat platelike 
base portion 31. A front end portion (right end portion in FIGS. 5 and 6) 
of the base portion 31 is folded back and put together with the upper 
surface of the short-circuit terminal fitting. A pair of elastic contact 
portions 32 extend rearward from the fold-back portion of this front end 
portion. Each elastic contact portion 32 is fixed at one end thereof with 
the other end thereof hanging as a free end. 
A large area of the base portion 31 except the front end portion is 
substantially lower than the front end portion so as to ensure a large 
space for the deformation of the elastic contact portions 32. 
The free end of each elastic contact portion 32 is bent obliquely 
downwardly after being bent obliquely upwardly so as to incline forwardly, 
thereby forming a triangular pressing portion 33. The lock arm 21 presses 
this pressing portion 33 substantially from above. Since the pressing 
portion 33 is folded such that ends 33A of the pressing portions 33 are in 
contact with the upper surfaces of the elastic contact portions 32, a 
pressing force of the lock arm 21 can be effectively transmitted to the 
elastic contact portions 32. Further, since a rear bent surface 33B of the 
pressing portion 33 is obliquely inclined forward with respect to the 
coupling or insertion direction A (FIG. 1), a force generated by an other 
member contacting the pressing portion 33 from behind is diverted 
upwardly. In positions adjacent or before the pressing portions 33 are 
formed contact portions 34 which come into contact with the detection 
terminals 13 when the connector housings 10, 20 are properly engaged. 
The short-circuiting terminal fitting 30 is provided with a protection wall 
35 for protecting the elastic contact portions 32. The protection wall 35 
is comprised of side walls 35A extending substantially vertically from the 
opposite side edges of a rear end portion of the base portion 31 and a 
rear wall 35B extending substantially vertically from the rear edge of the 
base portion 31 with respect to the coupling direction A. Projections 36A 
provided at the rear edges of both side walls 35A are engaged with 
recesses 36B at the opposite side edges of the rear wall 35B to more 
securely position the side walls 35A and the rear wall 35B with respect to 
the base portion 31. The side walls 35A are positioned at the sides of the 
free ends of the elastic contact portions 32 and the rear wall 35B is 
located behind the free ends of the elastic contact portions 32, so that 
the protection wall 35, as a whole, substantially surrounds the free ends 
of the elastic contact portions 32. 
The height of the protection wall 35 is set slightly higher than that of 
the free ends of the elastic contact portions 32, and the pressing 
portions 33 project upward from the protection wall 35. The pressing 
portions 33 are displaced downwardly by being pressed by the lock arm 21 
such that the pressing portions 33 are concealed within the protection 
wall 35. At this time, a degree of elastic deformation of the elastic 
contact portions 32 caused by the downward displacement of the pressing 
portions 33 is below an elasticity limit thereof. In this state, the lock 
arm 21 comes into contact with the upper edge of the protection wall 35 
(FIG. 4), with the result that any further downward deformation of the 
elastic contact portions 32 can be prevented. 
Next, the action of this embodiment is described. 
While the short-circuiting terminal fitting 30 is handled alone before 
being mounted in the female connector housing 20, the leading ends of the 
elastic contact portions 32 are unlikely to get caught with each other or 
interfered by other member(s) since they are surrounded by the protection 
wall 35. Accordingly, it can be expected that the deformation of the 
elastic contact portions 32 be prevented. 
In mounting the short-circuiting terminal fitting 30 in the female 
connector housing 20, the short-circuiting terminal fitting 30 is inserted 
into the terminal receptacle 28 through an opening formed in the rear end 
surface of the female connector housing 20. At this time, since the 
short-circuiting terminal fitting 30 can be stably held in its specified 
configuration by the base portion 31 sliding along the bottom surface of 
the terminal receptacle 28, it can be easily and securely inserted. If the 
protection wall 35 is pressed by finger or other means, the 
short-circuiting terminal fitting 30 can be easily pressed into the 
terminal receptacle 28. 
Upon completion of the insertion when the front end portion of the base 
portion 31 is fitted into the fitting portion 29 of the terminal 
receptacle 28, lock portions 37 formed at the side edges of the base 
portion 31 cut in the side walls of the terminal receptacle 28, with the 
result that the short-circuiting terminal fitting 30 is so held as not to 
move in its withdrawal direction. 
Even if a foreign matter enters the terminal receptacle 28 through the 
opening in the rear end surface of the female connector housing 20 while 
the short-circuiting terminal fitting 30 is mounted in the female 
connector housing 20, it comes into contact with the protection wall 35 
instead of coming into direct contact with the elastic contact portions 
32. Thus, the deformation of the elastic contact portions 32 due to the 
entrance of the foreign matter can be prevented. 
Although there is a possibility that this foreign matter strikes against 
the bent surfaces 33B of the pressing portions 33 projecting upward of the 
protection wall 35, since the bent surfaces 33B are inclined forward, this 
striking force is diverted obliquely upward along the inclination of the 
bent surfaces 33B. Accordingly, a probability of damage to the elastic 
contact portions 32 can be reduced. 
Further, when an other member strikes against the operable member 23 of the 
lock arm 21, the lock arm 21 may be deformed to a larger extent than when 
the connector housings 10, 20 are partly engaged, thereby excessively 
pressing the elastic contact portions 32. However, as shown by solid line 
in FIG. 4, the lock arm 21 comes into contact with the upper edge of the 
protection wall 35, thereby preventing the elastic contact portions 32 
from being deformed more than specified. Thus, an excessive deformation of 
the elastic contact portions 32 beyond their elasticity limit can be 
prevented. 
When the connector housings 10, 20 are partly engaged, the elastically 
deformed lock arm 21 presses the pressing portions 33 downwardly as shown 
in FIG. 2, causing the elastic contact portions 32 to elastically deform. 
Accordingly, the contact portions 34 move away from the detection 
terminals 13. Since the detection terminals 13 are not short-circuited in 
this state, it can be known that the connector housings 10, 20 are partly 
engaged. 
When the connector housings 10, 20 are properly engaged, the lock arm 21 
elastically returns to its original position, freeing the pressing 
portions 33 as shown in FIG. 3. Accordingly, the elastic contact portions 
32 are displaced upwardly due to their elastic restoring forces and the 
contact portions 34 thereof come into contact with the detection terminals 
13 to short-circuit them. Thus, it can be known that the connector 
housings 10, 20 have been properly engaged. 
As described above, according to this embodiment, since the 
short-circuiting terminal fitting 30 is provided with the protection wall 
35, the deformation of the elastic contact portion 32 due to the 
interference by other member(s) can be prevented and an excessive 
deformation thereof due to the excessively pressed lock arm 21 can be 
prevented. 
The second embodiment as shown in FIG. 7 (A) differs from the first 
embodiment in the construction of the lock arm and protection wall. Since 
the other construction is same or similar as that of the first embodiment, 
no description is given on the same construction as well as its action and 
effects by identifying it by the same reference numerals. 
A bottom surface of a lock arm 21 according to the second embodiment is cut 
away to form a step acting as an inclination preventing portion 40. A 
protection wall 41 is higher than the protection wall 35 according to the 
first embodiment, and is engageable with the inclination preventing 
portion 40. 
When the lock arm 21 is deformed to a larger extent than the deflection 
sufficient for the connector housings to be partly engaged, the 
inclination preventing portion 40 of the lock arm 21 comes into engagement 
with the upper edge of the protection wall 41. In this state, the upper 
edge of the protection wall 41 is in contact with an angular corner 
portion of the inclination preventing portion 40 and, accordingly, the 
protection wall 41 is prevented from displacing to the left and right of 
FIG. 7 by the transition surface 40A and the bottom surface 40B being 
positioned in particular obliquely or in a slanted manner with respect to 
the distal end of the protection wall 41, when the lock arm 21 is 
deflected downwardly. This securely prevents the protection wall 41 from 
inclining to the left or right even if the lock arm 21 strongly strikes 
against the protection wall 41. 
The inclination preventing portion may be a recess, as shown in FIG. 7(B), 
wherein the protection wall 41 is fitted or inserted into a recess 40', 
when the lock arm 21 is deflected and interacts with the limiting surfaces 
40'A-40' C, thereby limiting the downward deflection of the lock arm 21 
and therefore of the elastic contact portions 32 and furthermore 
preventing a further displacement of the lock arm 21, preferably in any 
direction except the direction to its resting position in the undeflected 
state. 
The present invention is not limited to the described and illustrated 
embodiments. For example, the following embodiments are embraced by the 
technical scope of the present invention as defined in the claims. Besides 
the following embodiments, a variety of changes can be made without 
departing the spirit and scope of the present invention as defined in the 
claims. 
In the foregoing embodiments, description is given on a case where the 
short-circuiting terminal fitting is mounted in the female connector 
housing provided with the lock arm. However, according to the invention, 
the short-circuiting terminal fitting may be mounted in a connector 
housing which is not provided with a lock arm. 
Although an excessive deformation of the elastic contact portions is 
prevented by the lock arm coming into contact with the protection wall in 
the foregoing embodiments, the protection wall may not have a function of 
preventing an excessive deformation of the elastic contact portions 
according to the invention. 
In the foregoing embodiments, description is given on the construction in 
which the elastic contact portions are folded back from the flat platelike 
base portion. However, according to the invention, the base portion on 
which the elastic contact portions are supported may not be flat 
platelike, but of another suitable shape. 
In the foregoing embodiments the deflection of the elastic contact portion 
32 was performed by its interaction with the lock arm 21 being deflected. 
However there may be provided a deflection means other than a lock arm 21 
such as a slanted projection (not shown) provided on the housing 10 
capable of deflecting downward the elastic contact portion 32 upon 
coupling of the two connector housing 10, 20, thereby interrupting the 
electrical contact between the short-circuit terminal 30 and the detection 
terminals 13 in a partly engaged state of the connector housings 10, 20 
and allowing for electrical contact between the short-circuit terminal 30 
and the detection terminals 13 thereby short-circuiting them in an engaged 
state of the connector housings 10, 20.