Rear holder having a releasing hole which extends beyond a rear end of a connector housing

A flat rectangular rear holder having groovelike wire inserting parts and a thickness. On a side surface of the rear holder are retaining projections for retaining a housing and a releasing hole for inserting a releasing jig. The rear holder is engaged with the housing that has a plurality of terminal accommodating chambers on a rear end thereof and retaining holes corresponding to the retaining projections along the peripheral wall thereof. With the rear holder engaged with and retained by the housing, an upper end part of the rear holder is projected from the rear end of the housing, so that the upper part of the releasing hole is exposed. This exposed part has an opening area so large as to allow a rear holder releasing jig to be inserted thereinto.

BACKGROUND OF THE INVENTION 
1. Field of the invention 
The invention relates to a rear holder that prevents a connection terminal 
inserted into a connector housing (hereinafter referred to simply as 
"housing") from coming off the rear end of the housing, the connector 
housing being used for connecting an electrical wiring system of an 
automobile or the like. More particularly, the invention is directed to a 
rear holder structure adapted for the operation of releasing the rear 
holder during maintenance. 
2. Related art 
Various connectors used for the connection of wire harnesses in an 
electrical system of an automobile or the like are designed such that a 
rear holder is engaged with the rear end of the housing so as to prevent a 
wired connection terminal accommodated within the housing from coming off 
or being displaced due to externally applied impact and the like. That is, 
the rear holder is engaged with the rear end of the housing after the 
wired connection terminal has been accommodated in the housing, so that 
the connection terminal is doubly retained from the rear as well. A 
conventional example having such a doubly retained mechanism is shown in 
FIG. 10. 
As shown in FIGS. 10 and 11, a rectangular rear holder 51 has retaining 
projections 53 on the side surface, and is engaged with a housing 30 
having retaining holes 31 on the rear end. A conventional procedure for 
releasing the rear holder 51 from the housing 30 using a rear holder 
releasing jig 20 during maintenance will hereunder be described. 
The plurality of retaining projections 53 provided on the side surface of 
the rear holder 51 are retained by the plurality of retaining holes 31 
provided on the rear end of the housing 30. As a result, the rear holder 
51 is engaged with and held by the housing 30. That is, the rear holder 51 
is engaged with the housing 30 without being projected from the rear end 
of the housing 30. 
Further, as shown in FIGS. 10 and 11, in order to disengage the rear holder 
51 from the housing 30, a rear holder releasing jig 20 is used to release 
the retaining projections 53 from the retaining holes 31 of the housing 30 
one by one. That is, the rear holder releasing jig 20 is inserted into a 
clearance between the housing 30 and the rear holder 51 which are engaged 
with each other, and force is then applied in a direction D to remove the 
rear holder 51 from the housing 30. 
FIG. 12 is a perspective view showing a state in which the retainment of 
the rear holder 51 has been released from the housing 30. 
However, the aforementioned conventional releasing method suffers from the 
problem that the retaining projections 53 and the retaining holes 31 on 
the side of the housing 30 are damaged by the releasing jig since the 
operation of releasing the retainment is performed by locally applying 
force to the retaining projections made of a low-hardness resin using a 
sharp-edged releasing jig made of metal. In addition, when there is a 
large number of retainment projections much time is required for complete 
removal of the rear holder from the housing, which in turn has impaired 
impairs maintenance operability. 
SUMMARY OF THE INVENTION 
The invention has been made to overcome the above problems. Accordingly, 
the object of the invention is to provide a rear holder capable not only 
of facilitating the operation of releasing the rear holder at the time of 
maintenance, but also of improving durability by preventing damage to the 
connector housing encountered during the releasing operation. 
To achieve the above object, a first aspect of the invention is applied to 
a rear holder having a wire inserting part in a direction of engagement 
thereof with a connector housing and a retaining projection on a side 
surface thereof, and being engaged with the connector housing with the 
retaining projection retained by a retaining hole provided on the 
connector housing, so that the rear holder prevents a connection terminal 
inserted into the connector housing from coming off a rear end of the 
connector housing, wherein a releasing hole allowing an operating part of 
a releasing jig to be inserted thereinto is provided on the side surface 
of the rear holder, so that when the rear older is retained by the 
connector housing, at least a part of the releasing hole is exposed from 
the rear end of the connector housing. 
To achieve the above object, a second aspect of the invention is applied to 
a rear holder wherein a thickness of the rear holder is set to such a 
value as to allow at least the part of the releasing hole to be exposed 
from the rear end of the connector housing when the rear holder is 
retained by the connector housing. 
To achieve the above object, a third aspect of the invention is applied to 
a rear holder comprising: a rear holder main body having a wire inserting 
part in a direction of engagement thereof with a connector housing and a 
retaining projection on a side surface thereof, the retaining projection 
being retained by a retaining hole provided on the connector housing; and 
a pair of rear covers coupled integrally with the rear holder main body, 
so that the rear holder prevents a connection terminal inserted into the 
connector housing from coming off a rear end of the connector housing, 
wherein a releasing hole allowing an operating part of a releasing jig to 
be inserted thereinto is provided on the side surface of the rear holder 
main body, so that when the rear older main body is retained by the 
connector housing, at least a part of the releasing hole is exposed from 
the rear end of the connector housing. 
To achieve the above object, a fourth aspect of the invention is applied to 
a rear holder wherein a thickness of the rear holder main body is set to 
such a value as to allow at least the part of the releasing hole to be 
exposed from the rear end of the connector housing when the rear holder 
main body is retained by the connector housing, and a width of each of 
hinges coupling the rear covers is set to a large value so as to 
correspond to the thickness of the rear holder main body. 
The rear holder of the invention is provided as arranging such a releasing 
hole as to allow the operating part of the releasing jig to be inserted 
thereinto on the side surface of the rear holder and thereby allowing at 
least a part of the releasing hole to be exposed from the rear end of the 
housing when the rear holder is retained by the housing. 
Therefore, in the operation of removing the rear holder from the housing, 
the operating part of the releasing jig can be inserted into the releasing 
hole with ease, and in addition, the retainment of the rear holder can be 
released at a time by turning the releasing jig in the releasing 
direction. 
Further, the rear holder of the invention is also provided as setting the 
thickness of the rear holder to such a value as to allow at least a part 
of the releasing hole to be exposed from the rear end of the housing when 
the rear holder is engaged with the housing. 
Therefore, not only the releasing hole can be exposed without manually 
handling the housing, but also the formation of the releasing hole 
contributes to lightening the inside of the rear holder, which in turn 
prevents shrinkage cavity, warpage, and the like of the rear holder due to 
the increased thickness. 
Still further, the rear holder of the invention is also provided as 
arranging such a releasing hole as to allow the operating part of the 
releasing jig to be inserted thereinto on the side surface of the rear 
holder main body and thereby allowing at least a part of the releasing 
hole to be exposed from the rear end of the housing when the rear holder 
main body is retained by the housing. 
Therefore, in the operation of removing the rear holder from the housing, 
the operating part of the releasing jig can be inserted into the releasing 
hole with ease. In addition, the retainment of the rear holder can be 
released at a time by turning the releasing jig in the releasing 
direction, and therefore the rear covers and the like in no way hinder the 
releasing operation. 
Still further, the rear holder of the invention is also provided not only 
as setting the thickness of the rear holder to such a value as to allow at 
least a part of the releasing hole to be exposed from the rear end of the 
housing when the rear holder is engaged with the housing, but also as 
setting the width of the hinge coupling the rear cover to a 
correspondingly large value. 
Therefore, not only the releasing hole can be exposed without manually 
handling the housing, but also the forming of the releasing hole 
contributes to lightening the inside of the rear holder, which in turn 
prevents shrinkage cavity, warpage, and the like of the rear holder due to 
the increased thickness. 
Still further, the reinforcement of the hinges contributes to improving 
durability of the rear holder.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
A rear holder, which is a first embodiment of the invention, will now be 
described with reference to FIGS. 1 to 6. 
As shown in FIG. 1, a rear holder 1, which is the first embodiment of the 
invention, is a rectangular flat member having groovelike wire inserting 
parts 4 and a thickness of w. On a side surface are retaining projections 
3 for retaining a housing 10 and a releasing hole 2 for inserting a 
releasing jig. The housing 10 will be described later. This rear holder 1 
is engaged with the housing 10 that has a plurality of terminal 
accommodating chambers 12 on the rear end thereof and retaining holes 11 
corresponding to the retaining projections 3 along the peripheral wall 
thereof. 
As shown in FIG. 2, with the rear holder 1 engaged with and retained by the 
housing 10, the upper end part of the rear holder 1 is projected from the 
rear end of the housing 10, so that the upper part of the releasing hole 2 
is exposed. This exposed part has an opening area so large as to allow a 
rear holder releasing jig 20 to be inserted thereinton. 
As shown in FIG. 3, the rear holder 1 and the housing 10 are engaged with 
each other, with the retaining projection 3 of the rear holder 1 being 
retained by the retaining hole 11 of the housing 10. The thickness w of 
the rear holder 1 is set to a value larger than that of the conventional 
example so that the rear holder can be projected from the rear end of the 
housing 10. Therefore, the upper part of the releasing hole 2 bored inward 
from the rear holder 1 side surface is exposed from the rear end of the 
housing 10 as an exposed part e. 
An operating part of the rear holder releasing jig 20 is inserted into the 
releasing hole 2 from this exposed part e with small insertion force in a 
direction S, so that the operation of releasing the rear holder 1 from the 
housing 10 is started. 
As shown in FIG. 4, the rear holder releasing jig 20 is further inserted 
into the depth of the releasing hole 2. Then, when the rear holder 
releasing jig 20 is turned in a direction B, the operating part of the 
releasing jig comes in contact with the upper end of the entrance of the 
releasing hole 2. As the rear holder releasing jig 20 is further turned 
with this point of contact as a pivot P, strong releasing force is applied 
to the rear holder 1 through the pivot P. 
Hence, as shown in FIGS. 5 and 6, the retaining projection 3 comes off the 
retaining hole 11, so that the rear holder 1 is released from the housing 
10 with ease by a single round of releasing operation. 
As described above, the rear holder 1, which is the first embodiment of the 
invention, has the thickness thereof set to a value larger than that of 
the conventional example so that at least a part of the releasing hole 2 
is exposed from the rear end of the housing 10 when the rear holder 1 is 
engaged with the housing 10. 
As a result of this construction, the rear holder releasing jig 20 can be 
inserted with small inserting force, thereby allowing the rear holder 1 in 
the retained state to be released from the housing 10 at a time. 
Hence, even if the rear holder is retained at many positions of the housing 
10, the rear holder 1 can be removed with a single round of releasing 
operation. 
In addition, since the releasing operation is performed by inserting the 
rear holder releasing jig 20 into the releasing hole 2, damage often given 
to the retaining projections 3 or to the retaining hole 11 during the rear 
holder 1 releasing operation can be minimized. 
Further, the releasing hole 2 formed on the side surface of the rear holder 
1 amounts, so to speak, to lightening the inside of the rear holder 1, 
thereby preventing shrinkage cavity, warpage, and the like from occurring 
during the molding of the rear holder. 
A rear holder, which is a second embodiment of the invention, will be 
described next with reference to FIGS. 7 and 8. FIG. 7 is an exploded 
perspective view of a rear holder, which is the second embodiment of the 
invention; and FIG. 8 is a perspective view showing an initial state of 
the operation of releasing the rear holder of FIG. 7 that is engaged. 
As shown in FIG. 7, a rear holder 21 includes: a rear holder main body 22 
and a pair of rear covers 23, 23. The rear holder main body 22 has a 
plurality of groovelike wire inserting parts 27 in a direction of 
engagement, and the pair of rear covers 23 are integrally coupled by 
hinges 24 with the rear holder main body 22. On the side surface of the 
rear holder main body 22 are a plurality of retaining projections 25 and a 
releasing hole 26 bored toward the inside of the rear holder main body 22. 
Further, on the side of a housing 15 are a plurality of retaining holes 16 
and hinge inserting notches 17, 17 into which the hinges 24 are inserted. 
These retaining holes 16 and the hinge inserting notches 17 are arranged 
on the rear end of the housing 15 (the upper end as viewed in FIG. 7). 
As shown in FIG. 8, the plurality of retaining projections 25 provided on 
the side surface of the rear holder main body 22 of the rear holder 21 are 
retained by the plurality of retaining holes 16 on the housing 15 with the 
rear holder 21 engaged with and retained by the housing 15. 
In the case of removing the rear holder 21 from the housing 15 by releasing 
the engagement of the rear holder 21 with the housing 15, the rear holder 
releasing jig 20 is inserted into the releasing hole 26 of the rear holder 
main body 22, so that the releasing operation is started. 
In a manner similar to the first embodiment, the rear holder main body 22 
of the rear holder 21 is projected from the rear end of the housing 15 
when the rear holder 21 is engaged with the housing 15 so as to facilitate 
insertion of the rear holder releasing jig 20 into the releasing hole 26. 
That is, at least the upper part of the releasing hole 26 arranged on the 
side surface of the rear holder main body 22 is exposed. It may be noted 
that the exposed area must be so large as to allow the operating part of 
the rear holder releasing jig 20 to be inserted thereinto. 
To have the upper part of the releasing hole 26 exposed, the rear holder 
21, which is the second embodiment of the invention, is provided not only 
as setting the thickness of the rear holder main body 22 to a large value 
only at the part to be exposed, but also as optimizing the location of the 
retaining projections 25 and the releasing hole 26. 
The increased thickness of the rear holder main body 22 may likely cause 
shrinkage cavity, warpage, and the like at the time of molding the rear 
holder 21. However, the rear holder 21 according to the second embodiment 
of the invention can prevent occurrence of the shrinkage cavity, warpage, 
and the like at the time of molding the rear holder since the forming of 
the releasing hole 26 on the side surface of the rear holder main body 22 
amounts, so to speak, to lightening the inside of the rear holder. 
Further, as shown in FIG. 7, the rear holder 21, which is the second 
embodiment of the invention, is also provided as allowing the width of the 
hinge 24 to be maximized to a value as thick as the rear holder main body 
22 so as to correspond to the thickness w of the rear holder main body 22. 
Therefore, the bending resistance of the hinges 24, 24 can be improved, 
which in turn contributes to significantly improving durability of the 
hinges 24, 24 with respect to the opening and closing operation of the 
rear covers 23, 23 and thus increasing durability of the rear holder 21. 
Furthermore, to reserve a larger exposed area of the releasing hole 26, 
e.g., a jig inserting notch 18 may be provided on the rear end of the 
housing 15 separately from the hinge inserting notches 17, 17 as shown in 
FIG. 9. As a result of this construction, the operation of inserting the 
rear holder releasing jig 20 into the releasing hole 26 is facilitated, 
thereby further improving operability at the time of maintenance. 
As described in the foregoing, the rear holder of the invention is provided 
not only as allowing the rear holder to be projected from the rear end of 
the housing by setting the thickness of the rear holder to a large value, 
but also as forming a releasing jig inserting hole, which is equivalent to 
the lightening of the rear holder on the side surface of the rear holder 
so that at least the upper part of the releasing hole can be exposed when 
the rear holder is engaged with the housing. 
Therefore, not only the releasing jig can be inserted into the releasing 
hole with ease, but also the retainment of the rear holder can be released 
reliably by a single round of releasing operation even if the rear holder 
is retained by the housing at many locations, thereby remarkably improving 
operability. 
In addition, the operating part of the releasing jig is not likely to 
operate on the retaining projections of the rear holder and on the 
retaining hole of the housing directly, thereby eliminating damage 
conventionally often caused to the retaining projections or to the 
retaining hole. 
As a result, not only durability of the retaining parts of the rear holder, 
the housing, and the like can be remarkably improved, but also parts loss 
can be significantly reduced since the parts can be reused repetitivel 
Still further, not only the thickness of the rear holder is set to a large 
value, but also the releasing hole formed on the side surface serves as 
lightening, which in turn reliably prevents shrinkage cavity, warpage, and 
the like caused at the time of molding the rear holder. 
Still further, with respect to the rear holder having the rear covers, the 
thickness of the hinge can also be set to a large value so as to 
correspond to the increase in the thickness of the rear holder, which not 
only improves the life of the hinge but also significantly ameliorates 
durability of the rear holder.