Fitting detection connector

One connector housing includes a resilient locking arm having a through-hole provided at its tip, a pair of detection terminals attached to said resilient locking arm and opposed to the through-hole, a first spring portion provided on the side of a warping space of the resilient locking arm and inserted between the resilient locking arm and the pair of detection terminals, the first spring portion having a protrusion to be engaged in said through-hole so as to force the locking arm in an anti-warping direction, and a second spring portion always forcing said resilient locking arm in the anti-warping direction. Another connector housing includes an engagement protrusion which is to be engaged in the through-hole to push the protrusion, thereby warping the first spring portion in an anti-forcing direction to be brought into contact with the pair of detection terminals. Thus, connector fitting of one and another connector housings can be surely detected electrically. The fitting detection connector can have a buffer spring member which is arranged between the contact portion and intrusion protrusion of the first spring portion.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a fitting detection connector which can 
electrically detect whether female and male connector housings have been 
fit into each other. The present invention also relates to a detection 
contact spring structure and a detection terminal deformation preventing 
structure which are used for the above fitting detection connector. 
2. Description of the Prior Art 
FIGS. 17 and 18 show a conventional fitting detection connector disclosed 
in Japanese Utility Model Publication No. Hei 4-3419. 
This connector 28 includes one connector housing 29 with a connector 
fitting detection portion 30 provided on its outside. A sub-housing 33 of 
insulating resin composed of a terminal chamber 31 and a contact member 
insertion portion 32 is attached to the exterior wall of the housing 29. A 
pair of detection terminals 34, 34 are incorporated in the chamber 31 so 
that the respective tip male tabs 35, 35 are projected in parallel from 
the sub-housing 33. A contact member 36 having an shape is inserted and 
locked in the insertion portion 32 and its contact springs 37, 38 having 
different heights are opposed to the respective male tabs 35, 35. As seen 
from FIG. 18, the tip 41 of a resilient locking arm 40 of the other 
connector housing 39 presses a non-contact side contact spring piece 37 as 
shown in a dotted line so that the above pair of male tabs 35, 35 are 
brought into contact with the pair of contact spring pieces 37, 38. Thus, 
the fitting in the connector 28 can be detected. 
The above connector structure has a disadvantage that the connector 28 
itself becomes large because the fitting detection portion 30 is projected 
from the outside of the connector housing 29. Further, when the resilient 
locking arm 40 sits on and is engaged with the protrusion 42 of the one 
housing 29, the restitutive force of the locking arm 40 is weakened so 
that the pressing force of the contact piece 37 becomes insufficient. For 
this reason, the detection of fitting may become uncertain. 
JP-A (Laid-Open) Sho 61-186180 also discloses a conventional fitting 
detection connector, particularly a detection terminal deformation 
preventing structure. This structure has the same disadvantage as in the 
conventional fitting detection connector disclosed in JU-Publication No. 
Hei 4-3419. 
SUMMARY OF THE INVENTION 
A first object of the present invention is to provide a fitting detection 
connector which can surely detect connector fitting without increasing the 
volume of the connector itself and injuring the restitutive force of a 
resilient locking arm. 
A second object of the present invention is to provide a fitting detection 
connector which can bring a contact spring member into contact with a 
detection terminal with sufficient contact pressure so as to enable sure 
fitting detection. 
A third object of the present invention is to provide a detection terminal 
deformation preventing structure for a fitting detection connector which 
can prevent deformation of a detection terminal so as to enable sure 
fitting detection. 
In order to attain the first object, in accordance with the first aspect of 
the present invention, there is provided a fitting-detection connector 
comprising: one connector housing including a resilient locking arm having 
a through-hole provided in its tip, a pair of detection terminals attached 
to said resilient locking arm and opposed to said through-hole, a first 
spring portion provided on the side of a warping space of said resilient 
locking arm and inserted between said resilient locking arm and said pair 
of detection terminals, said first spring portion having an intrusion 
protrusion engaged in said through-hole so as to force said locking arm in 
an anti-warping direction, and a second spring portion always forcing said 
resilient locking arm in the anti-warping direction; and another connector 
housing having an engagement protrusion which is engaged in said 
through-hole to push said intrusion protrusion, thereby warping said first 
spring portion in an anti-forcing direction to be brought into contact 
with said pair of detection terminals. 
In connector fitting, an engagement protrusion of the other connector 
housing warps the resilient locking arm of one connector housing so that 
it is engaged into a through-hole. The engagement protrusion pushes and 
moves the protrusion of a first spring portion so that the first spring 
portion is brought into contact with a pair of detection terminals. Thus, 
the pair of terminals are short-circuited to make electrical connection. 
The first spring portion is pushed by the engagement protrusion so as to 
be released from the resilient locking arm. A second spring portion forces 
the locking arm in an anti-warping direction to give the restitutive force 
to locking arm. 
In the structure in which the first spring is divided into a movable 
contact portion and a fixed contact portion, its intrusion protrusion is 
pushed by the engagement protrusion so as to bring the movable contact 
portion into contact with the one detection terminal and make an 
electrical connection with the other detection terminal through the second 
spring and fixed contact portion. 
In accordance with the present invention, since the detection terminal for 
electrically detecting the connector fitting and the spring portion are 
located inside the resilient locking arm and on the side of the arm 
resilient space, a slim connector shape can be obtained. Since the first 
spring portion is pushed by not the resilient arm but by the rigid 
engagement protrusion of a partner connector housing to make a contact 
with the detection terminal, the reliability of the electrical detection 
can be improved. Even after the first spring portion is brought into 
contact with the detection terminal, the second spring forces the 
resilient arm in an anti-warping direction so that arm locking can be 
surely made. 
In order to attain the second object of the present invention, in the 
fitting-detection connector according the first aspect of the present 
invention, in accordance with the second aspect, a buffer spring portion 
being is formed between the intrusion protrusion and a contact portion of 
the first spring portion. 
In operation, at the time of connector fitting, the engagement protrusion 
of another connector housing intrudes into the through-hole of the 
resilient locking arm of one connector housing to push the intrusion 
protrusion of the detection contact spring member, thereby bringing the 
contact portion of said detection contact spring member into contact with 
the detection terminals. Then, the buffer spring portion of said detection 
contact spring member warps to absorb excessive pressing force of the 
engagement protrusion so that the contact portion is resiliently brought 
into contact with the detection terminals. This assures persistent 
electric contact, thus improving fitting detection in the connector. 
Further, the buffer spring portion absorbs the excessive pressing force of 
the engagement protrusion so that the deformation of the detection 
terminals can be prevented. 
In order to attain the third object of the present invention, in accordance 
with the third aspect of the present invention, the fitting-detection 
connector can further includes a resilient plate protruding from the lower 
end of said resilient locking arm whereby said detection terminals are 
prevented from being deformed. 
In operation, at the time of connector fitting, the engagement protrusion 
of the other connector housing is engaged in the through-hole of the 
resilient locking arm to push the protrusion of the spring member. Thus, 
the contact portion of said spring member is brought into contact with the 
pair of detection terminals. Now even if the pressing force of the 
engagement protrusion is large, when the detection terminals are pushed to 
warp, the resilient plate warps simultaneously to absorb excessive 
pressing force. This prevents the plastic deformation in the detection 
terminals and sure contact pressure. When the pressing force by the 
engagement protrusion is released, the detection terminals are restored to 
the original position owing to resiliency of said resilient plate. Since 
the pressing force by the engagement protrusion, i.e. contact pressure of 
a twisted coil spring and detection terminal can be set for a large value, 
thereby improving the reliability of electrical connection. Further, when 
the pressing force of the engagement protrusion is released, the resilient 
plate resiliently restores the detection terminals to their initial 
positions. This improves repetitive durability and enables sure fitting 
detection even when fitting and removal of the connector are carried out 
many times. 
The above and other objects and features of the present invention will be 
more apparent from the following description taken in conjunction with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Embodiment 1 
FIGS. 1 to 5 show one embodiment of a fitting detection connector according 
to the present invention. 
The fitting detection connector 1 is generally composed of a female 
connector housing 4 of insulating resin in which a resilient locking arm 3 
having a through-hole at its tip is internally arranged; a pair of 
detection terminals to be mounted in the lower half of the resilient 
locking arm, a twisted coil spring member 9 having a pair of spring 
portions 7 and 8 for forcing the resilient locking arm 3 in an 
anti-warping direction, which is arranged on the side of resilient space 
of the resilient arm 3 within the female connector housing 4; and a male 
connector housing 12 having an engagement protrusion 11 for pressing the 
tip-side protrusion 10 of the one spring portion 7 engaged into tip-side 
through-hole 2 of the resilient arm 3. 
The female connector housing 4 includes a partner connector fitting chamber 
13 in its front part and the above resilient locking arm 3 in its rear and 
upper part. The resilient locking arm 3 protrudes the tip portion 14 
having the through-hole 2 in the warping direction into the fitting 
chamber 13, and accommodates a pair of detection terminals 6, 6 in its 
rear half part stepwise-protruding from the tip portion 14 as shown in 
FIG. 2. The locking arm 3 can be warped up and down around a fulcrum 
portion 15 on the stem side. The tip male tab 16 of the detection terminal 
6 is protruded from the terminal chamber 17 (FIG. 1) in the lower half 
portion 5 into the fitting chamber 13 through a through-hole 18 so that it 
is located opposedly to the lower side of the through-hole 2. 
Further, a pair of fulcrums 20, 20 for the above twisted coil spring member 
9 are protruded from both rear side walls 19, 19. The coil portion of the 
spring member 9 is engaged in the fulcrum 20 so that the spring member 9 
is located in the warping space on the lower side of the resilient arm 3. 
The twisted coil spring member 9 has a first spring portion which is 
straight and relatively long on the upper side of the coil member 21 and a 
second spring portion 8 which is relatively short and bent in a "&lt;" shape 
of on the lower side of the coil member 21. 
As seen from FIG. 5, the first spring portion 7 has a square shape of 
generally anti- and is composed of lengthy portions 7a, 7a on both sides 
which extend in the longitudinal direction of the resilient arm 3 from the 
coil portion 21 and an orthogonal portion 7b connects the tips of both 
lengthy portions 7a, 7a. The orthogonal portion 7b has the above 
protrusion 10 of a bent square shape which is formed at its central 
position and intrudes into the through-hole 2 of the resilient arm 3. The 
orthogonal portion 7b is passed between the resilient locking arm 3 and 
the male tabs 16, 16 of the pair of the terminals 6, 6, and abuts on the 
lower surface 14a of the tip of the resilient arm 3 to force the locking 
arm 3 toward the anti-warping direction. The orthogonal portion 7b of the 
first spring portion 7 is opposed to the male tab 16 in a non-contact 
state with a slight gap S (see FIG. 2). 
The second spring portion 8 extends in a form bent in a "&lt;" shape from the 
coil portion 21 to abut its tip 8a on the lower wall of he lower half 
portion (terminal chamber) of the resilient arm 3 so that the locking arm 
3 is always forced in the anti-warping direction. The locking arm 3 has a 
removal pressing operation part 23 protruding in the rear of the 
through-hole 2. The rear of the removal pressing operation part 23 is 
abutted on the stopping protrusion 24 protruding in a crossing direction 
of the arm 3 from the female connector housing 4. The tip 14 of the 
locking arm is provided with an upward tapering guide 14b for inner 
engagement protrusion 11 at the tip of a partner connector housing 12. 
As shown in FIG. 3, in connector fitting, the resilient locking arm 3 is 
pressed, in its tip 14, to the engagement protrusion 11 and warps downward 
against the spring forcing. As shown in FIG. 4, the resilient locking arm 
3 is restored to its initial form when the engagement protrusion is 
engaged in the through-hole 2. The protrusion 10 of the first spring 
portion 7 located in the through-hole 2 is pushed by the engagement 
protrusion 11 to press down the first spring portion itself downwards. 
Thus, the orthogonal portion 7b of the first spring portion 7 is brought 
into contact with the male tabs 16, 16 of the pair of detection terminals 
so that the fitting of the connector 1 is electrically detected. 
Although the first spring portion 7 is pressed down by the engagement 
protrusion 11 so that the it becomes apart from the resilient arm 3, the 
second spring portion 8 always forces the arm 3 in a pressing-up 
direction. Thus, resilient locking of the resilient arm 3 can be assured. 
Further, since the engagement protrusion 11 which is not resilient but 
rigid presses down the first spring portion 7, electrical connection 
between the first spring portion 7 and the detection terminals 6, 6 can be 
assured. 
Further, the longitudinal portion 7a' of the first spring portion 7' may be 
bent in an arc shape as shown in FIG. 6. In this case, when such a 
longitudinal portion 7a' is pressed down by the engagement protrusion 11, 
it will be further bent to absorb redundant pressing force. The stored 
spring force due to bending increases the restitutive force of the first 
spring portion 7', thus improving spring durability. 
Embodiment 2 
FIGS. 7 to 9 show another embodiment of the fitting detection connector 
according to the present invention. FIG. 8 shows a twisted coil spring 
member 43 in this embodiment. As seen from FIG. 8, the front orthogonal 
portion 44b is divided into a movable contact portion 45 opposed to the 
first detection terminal 161 and a fixed contact portion 46 kept in 
contact with the other detection terminal 16.sub.2. A protrusion 47 
engaged in the through-hole of the resilient locking arm 3 is formed 
integrally to the tip of the movable contact portion 45. The stems of a 
pair of longitudinal portions 44a, 44a having both contact portions 45 and 
46 are connected to each other by a second spring portion having an anti- 
shape which is successive to a coil portion 48 engaged with a fulcrum 20. 
The second spring portion 49 is composed of a pair of longitudinal portions 
49a, 49a each bent in a "&lt;" shape and an orthogonal portion 49b which 
connects the pair of longitudinal portions 49a, 49a with each other and is 
in press-contact with the lower half portion 5 of the resilient arm 3. The 
movable contact portion 45 and the fixed contact portion 46 are separated 
by a gap L from each other in a free state. As shown in FIG. 9, in a state 
where the engagement protrusion 11 of a partner connector is engaged with 
the through-hole 2 of the resilient locking arm 3, the movable contact 
portion 45 is warped downward as a result that its protrusion 47 is 
pushed, thereby being brought into contact with the detection terminal 
16.sub.1. Thus, the pair of detection terminals 16.sub.1 and 16.sub.2 
become conductive through the twisted spring member 43 so that the 
connector fitting can be electrically detected. 
Embodiment 3 
This embodiment is directed to a detection contact spring structure. FIGS. 
10 to 12 show the detection contact spring structure for a fitting 
detection connector according to the present invention. In FIGS. 10 to 12, 
like reference numerals refer to like parts in FIGS. 1 to 7. This 
structure is characterized in that as a buffer spring structure 57 of a 
detection contact spring member 9 is arranged between a resilient locking 
arm 3 attached to one connector housing 4 and protruding male tabs 16, 16 
of a pair of detection terminals 6, 6 attached on the lower half 5 of the 
resilient locking arm 3. 
The detection contact spring member 9, as shown in FIG. 11, is composed of 
long spring portions 7, 7 left and right opposite to each other, contact 
portions 59, 59 corresponding to the pair of male tabs 16, 16 formed 
integrally and orthogonally to the long spring portions 7, 7 at their 
tips, buffer spring portions 57, 57 having an character shape which are 
formed toward the lower surface of the tip portion 14 of the resilient 
locking arm 3 from each of contact portions 59, 59, abutting portions 61, 
61 integral to the upper portions of the buffer spring portions 57, 57, 
the abutting portions 61, 61 abutting on the tip portion 14 of the 
resilient locking arm 3, an intrusion protrusion 10 for a through-hole 2 
of the tip portion 14, the intrusion portion 10 being formed at the center 
of the abutting portion 61, an engagement coil portion 21 for a supporting 
shaft 20 of the connector housing 4, the engagement coil portions 21 being 
formed at the stem of the long spring portions 7, and short spring 
portions 8, 8 which always force the lower half of the resilient arm 3 are 
integral to the engagement coil portions 21, 21. In the unfitting state of 
the connector, the contact portions 59, 59 are separated upwards from the 
male tabs 16, 16 and the abutting portions 61, 61 force the tip portion 14 
of the resilient arm 3 in an anti-warping direction (upward). 
Each of the buffer spring portions 57, 57, as shown in FIG. 11, is composed 
of an inner vertical portion 67 extending upwards from the inner end of 
the contact portion 59, a horizontal portion 68 outwardly extending in 
parallel to the contact portion 59 from the vertical portion 67, an outer 
vertical portion 69 extending from the outer end of the horizontal portion 
68 to the abutting portion 61 and the abutting portion 61 in parallel to 
the horizontal portion 68. The buffer spring portions 57, 57 warp up and 
down at the time of connector fitting to absorb excessive pressing force 
of the engagement protrusion 11 of the other connector 12. Specifically, 
the abutting portion 61 and the horizontal portion 68 warp in opposite 
directions to absorb the pressing force to bring the detection contacts 
59, 59 into resilient contact with the male tabs 16, 16. This assures 
contact pressure, thus preventing plastic deformation of the male tabs 16, 
16 due to excessive pressing force. 
Embodiment 4 
This embodiment intends to provide a specific structure for preventing 
deformation of detection terminals for a fitting detection connector 
according to the present invention. The basic structure of the fitting 
detection connector used in this embodiment has been explained with 
reference to FIGS. 1 to 7. 
As seen from FIGS. 13 to 16, in order to prevent plastic deformation of a 
pair of detection terminals 6, 6 and obtain their electrical contact at 
higher contact pressure, the structure according to this embodiment is 
characterized by a resilient plate 76 for reinforcement which is formed so 
as to protrude integrally from the lower half 5 of the resilient locking 
arm 3 and to be brought into intimate contact with the lower plate 
surfaces 75a, 75a of male tabs 16, 16 of the pair of detection terminals 
6, 6. 
The reinforcement resilient plate 76 is formed along the lower plate 
surfaces 75a, 75a of the male tabs 16, 16 so as to protrude the front edge 
74a of the lower half 5 of the locking arm 3 with a length substantially 
equal to that of the male tabs 16, 16. The resilient plate 76 has a width 
which is slightly larger than that of the pair of detection terminals 6, 
6. Namely, the resilient plate 76 protrudes slightly outwardly from the 
outer ends of the detection terminals 6, 6 in a horizontal direction. This 
intends to restrain the warping of the male tabs 16, 16 within a resilient 
range when the contact portion 82 of a twisted coil spring 76 pressed by 
the engagement protrusion 11 presses down the male tabs 16, 16 of the pair 
of detection terminals 6, 6. The reinforcement resilient plate 76 can warp 
integrally to the male tabs 16, 16 within the resilient limit of the male 
tabs 16, 16. When the fitting of the one and the other connector housings 
4 and 12 is removed, the pressure by the engagement protrusion 11 is 
released so that the resilient plate 76 restores to an initial position 
simultaneously with the male tabs 16, 16 of the detection terminals 6, 6. 
Specifically, as shown in FIG. 15, in fitting the male and female 
connectors 4 and 12, the engagement protrusion of the male connector 
housing 12 slides along the tip tapered face 14b of the resilient locking 
arm 3 to press down the resilient locking arm 3 against the force by a 
long spring portion 7 and a short spring portion 8. Then, as shown in FIG. 
16, when fitting is completed, the engagement protrusion 11 presses down 
the intrusion protrusion 10 of the long spring portion 7 to bring the 
contact portion 82 of the long spring portion 7 into contact with the 
upper plate surfaces 75b, 75b of the male tabs 16, 16 of the pair of 
detection terminals 6, 6. 
Now even if the pressing force by the engagement protrusion 11 is great, as 
seen from the enlarged view of FIG. 16, the resilient plate 76 warps 
integrally to the male tabs 16, 16 of the detection terminals 6, 6 to 
absorb weighting, thereby preventing the male tabs 16, 16 from being bent. 
Therefore, the contact pressure between the contact portion 82 of the coil 
spring 9 and the male tabs 16, 16 of the detection terminals 6, 6 can be 
set for a large value, thus assuring electric connection. Further, when 
the pressing force by the engagement protrusion 11 is released, the 
resilient plate 76 resiliently returns the male tabs 16, 16 to their 
original positions.