Structure for thin-walled hinge

An object of the present invention is to provide a structure employable for a thin-walled hinge(s) which assures that there does not arise a malfunction that each thin-walled hinge is undesirably bent and that an operation for connecting two components to each other and disengaged from each other can be performed at an improved efficiency. A pair of thin-walled hinges for firmly connecting a double engagement member to a housing main body are designed in the form of a pair of rectangular band-shaped pieces for connecting a lower wall of the housing main body on the male terminal insert side to a base end portion of a plate portion. To assure that opening and closing of the double engagement member are not obstructed by the thin-walled hinges, each thin-walled hinge is designed such that it has a small thickness enough to allow it to be deflected with a very low intensity of power, the width of each thin-walled hinge is continuously reduced from the connecting portion on the lower wall side toward the connecting portion of the plate portion side while each thin-walled hinge maintains a constant thickness therebetween, and a width W.sub.1 of each thin-walled hinge on the housing main body side is dimensioned to be larger than a width W.sub.2 of the same on the double engagement member side.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to a hinge including a fulcrum for 
turning movement thereof in the case that two components to be detachably 
combined with each other are integrally connected to each other, and 
subsequently, they are disconnected from each other as desired. More 
particularly, the present invention relates to improvement of a 
thin-walled hinge of the foregoing type to be integrally molded with the 
two components. 
2. Related Art 
A flexible thin-walled hinge including a fulcrum for turning movement 
thereof in the case that two components to be detachably combined with 
each other are integrally connected to each other and disconnected from 
each other as desired is hitherto practically used in various utilization 
fields in industries. 
The flexible thin-walled hinge having the aforementioned structure has 
advantages that e.g., in the case of a container having a lid attached 
thereto, a structure employable for a hinge of the foregoing type for 
allowing the lid to be turnably openably connected to a housing of the 
container can easily be produced, and moreover, an assembly of the lid and 
the housing of the container can integrally be molded at a reduced cost on 
a mass production line by employing an injection molding process. Owing to 
the foregoing advantages, many flexible thin-walled hinges each 
constructed in the above-described manner are used for electrical 
components such as fuse boxes, protectors for wire harnesses or the like 
in addition to containers each having a lid attached thereto as mentioned 
above. 
In view of the fact that a thin-walled hinge of the foregoing type is 
alternately subjected to compressive and tensile stresses due to bending 
and expanding thereof caused as it is opened and closed, it is constructed 
such that it can satisfactorily stand against the compressive and tensile 
stresses induced as it is opened and closed, by designing it to have a 
small thickness so as to maintain the radius of curvature in relatively 
large when it is bend. 
In addition, with respect to a terminal housing, it is already known that a 
double engagement member is disposed on a main body of the housing via a 
thin-walled hinge in order to increase an intensity of retaining power to 
be applied to a terminal primarily engaged with the housing by actuating 
conventional engaging means. FIGS. 6 to 8 show by way of perspective view 
the structure of a terminal housing of the foregoing type including a 
double engaging member. 
In the shown case, the terminal housing includes a partition wall 56 at the 
intermediate part of a housing main body 41 in order to prevent a male 
terminal 50 from being disconnected from the housing main body 41 in the 
forward direction, and the partition wall 56 is projected inward of the 
inner surfaces of a front wall 42a and a rear wall 42b of the housing main 
body 41. To prevent the male terminal 50 from being vibratively displaced 
in the housing main body 41, a lower housing main body 43 located below 
the partition wall 56 is designed to have a small width between a front 
wall 43a and a rear wall 43b compared with an upper housing main body 42. 
In addition, the front wall 43a of the lower housing main body 43 located 
below the partition wall 56 includes a terminal vibrative displacement 
preventing portion for preventing the male terminal 50 from being 
vibratively displaced, and the lower end of the terminal vibrative 
preventing portion is kept open to the outside in the form of an opening 
portion 46 (see FIG. 8). 
A housing lance 47 serving as a primary engagement member for the male 
terminal 50 is disposed on the inner surface of one of the opposite side 
walls 42c of the upper housing main body 42, and moreover, engagement 
protuberances 48 for holding a double engagement member 44 to be described 
later in the locked state are disposed on the outer surfaces of the 
opposite side walls 42c of the upper housing main body 42. 
The double engagement member 44 is prepared by bending the opposite side 
plates 44b each having an engagement hole 45 formed therethrough inside of 
a plate portion 44a of the double engagement member 44 at a right angle 
relative to the plate portion 44a along the opposite side edges of the 
latter. In practical use, the double engagement member 44, especially, the 
upper end part of the plate portion 44a is openably fitted into the 
opening portion 46 located below the front wall 42a of the housing main 
body 41 via a pair of thin-walled hinges 49 and a pair of hinge fitting 
base portions 49a. 
The thin-walled hinges 49 are prepared in the form of a pair of rectangular 
band-shaped pieces each serving to connect the lower end of the front wall 
42a to the hinge fitting base portion 49a. Each thin-walled hinge 49 is 
dimensioned to have a small thickness enough to allow each thin-walled 
hinge 49 to be deflected with a very low intensity of power without any 
possibility that opening and closing of the double engagement member 44 
are undesirably obstructed. In addition, since each thin-walled hinge 49 
has an adequately determined width, there does not arise a malfunction 
that bending of the thin-walled hinge 49 is achieved concentratively in a 
certain narrow region. Thus, local breakage of each thin-walled hinge 49 
can be prevented regardless of repeated opening and closing operations of 
the double engagement member 44. 
Primary engagement of the male terminal 50 with the terminal housing is 
achieved by way of the steps of first inserting the male terminal 50 into 
the main body 41 of the housing in the arrow-marked direction, bringing 
the opposite projections 52 projecting outside of an electrical contact 
portion 51 of the male terminal 50 in contact with the lower surface of 
the partition wall 56 of the housing main body 41, the front wall 43a of 
the lower housing main body 43 and the rear wall 43b of the same in order 
to prevent disconnection of the male terminal 50 from the housing main 
body 41 and vibrative displacement of the male terminal 50, and 
subsequently, bringing the housing lance 47 projecting from the housing 
main body 41 in engagement with an engagement hole 54 formed through a 
base plate 53 of the male terminal 50. 
Next, double engagement is achieved by way of the steps closing the opening 
portion 46 of the housing main body 41 with the double engagement member 
44 via the thin-walled hinges 49, bringing the engagement holes 45 formed 
through the side plates 44b in engagement with the engagement 
protuberances 48 on the housing main body 41 so as to hold the double 
engagement member 44 in the locked state, and subsequently, bringing an 
upper end surface 44c of the plate portion 44a in engagement with the 
lower surface of one of the projections 52 of the male terminal 50. 
With the thin-walled hinges 49 designed in the above-described manner, 
however, when the opening portion 46 of the housing main body 41 is closed 
with the double engagement member 44, it is not always assured that they 
are bent at the central parts as seen in the opening/closing direction, 
i.e., in the longitudinal direction of the thin-walled hinges 49. For 
example, as shown in FIG. 7, there arises an occasion that the thin-walled 
hinges 49 are not bent at the central parts thereof as seen in the 
longitudinal direction but they are sharply bent at the positions offset 
away from the central parts. Thus, the fulcrum for turning movement of the 
thin-walled hinges 49 is dislocated from a predetermined position, causing 
a radius of turning movement of the thin-walled hinges 49 to vary. This 
leads to the result that there arises a malfunction that the engagement 
holes 45 on the double engagement member 44 do not reach the engagement 
protuberances 48 on the main body 41 of the housing or they pass past the 
engagement protuberances 48. In view of an occurrence of the foregoing 
malfunction, a highly trained skill is required for an operator in order 
to assure that the double engagement member 44 is correctly held on the 
housing main body 41 in the locked state. In addition, there is existent a 
certain limit when each of the thin-walled hinges 49 is designed to have a 
smaller thickness so as to allow them to be easily bent. If each 
thin-walled hinge 49 is designed to have an excessively small thickness, 
the strength of the thin-walled hinge 49 is undesirably reduced in excess 
of a predetermined level. 
Therefore, in the case that two components to be detachably combined with 
each other are integrally connected to each other and disconnected from 
each other like the thin-walled hinges 49, there appears a problem that 
each inserting operation can not smoothly be performed when the 
aforementioned locking mechanism is employed for the thin-walled hinges 49 
each including a fulcrum for turning movement thereof. In addition, when 
the thin-walled hinges 49 are bent at the positions offset away from 
predetermined ones, breakage is liable to occur at the sharply bent 
positions. If they are sharply bent while exhibiting an acute angle with 
the thin-walled hinges 49, operator's fingers are liable to collide 
against the sharply bent parts of the thin-walled hinges 49, resulting in 
his fingers being injured with them. Another problem is that the terminal 
housing exhibits poor appearance due to the presence of the sharply bent 
parts of the thin-walled hinges 49. 
In the case that the double engagement member 44 is connected to the 
housing main body 41 via the thin-walled hinges 49 like the aforementioned 
terminal housing, if the thin-walled hinges 49 are sharply bent at the 
positions offset away from the predetermined ones when the opening portion 
46 of the housing main body 41 is closed with the double engagement member 
44, a certain intensity of power effective for slantwise raising up the 
upper end surface 44c of the plate portion 44a is exerted on the double 
engagement member 44 as shown in FIG. 8, resulting in the upper end 
surface 44c of the plate portion 44c failing to be engaged with the lower 
surface of one of the projections 52 of the male terminal 50. Thus, there 
is a possibility that double engagement can not reliably be achieved with 
the thin-walled hinges 49 designed in the above-described manner. 
SUMMARY OF THE INVENTION 
The present invention has been made in consideration of the aforementioned 
background and its object resides in providing a structure employable for 
a thin-walled hinge(s) which assures that there does not arise a 
malfunction that each thin-walled hinge is bent at the position offset 
away from a predetermined one and that an operation for connecting two 
components to each other and disconnecting from each other can be 
performed at an improved efficiency. 
To accomplish the above object, the present invention provides a structure 
employable for a thin-walled hinge(s) wherein two components to be 
detachably combined with each other are integrally connected to each 
other, wherein each thin-walled hinge is molded such that the width of the 
thin-walled hinge extending from the connecting portion of one component 
to the connecting portion of other component is continuously reduced while 
the thin-walled hinge maintains a constant thickness therebetween. 
With the structure as mentioned above, since a sectional area of each 
thin-walled hinge measured in the transverse direction varies in 
proportion to the bending moment exerted thereon, in the case that two 
components are connected to each other and disconnected from each other, a 
constant bending stress appears on each thin-walled hinge including a 
fulcrum for turning movement thereof in the longitudinal direction (i.e., 
in the bending direction). Thus, there does not arise a malfunction that 
the bending power is concentratively applied on a certain single location 
when the bending moment is exerted on each thin-walled hinge as the latter 
is turnably bent, whereby each thin-walled hinge can be deformed while 
exhibiting a constant curved configuration.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The present invention will now be described in detail hereinafter with 
reference to the accompanying drawings which illustrate a few preferred 
embodiments thereof. Incidentally, FIG. 1 is a perspective view of a 
female connector and a male terminal to be connected to each other via 
thin-walled hinges constructed according to an embodiment of the present 
invention, FIG. 2 is a front view of the female connector, and FIG. 3 is a 
vertical sectional view of the female connector having the male terminal 
received therein. 
As shown in FIGS. 1-3, in this embodiment, a female connector 1 is composed 
of a housing main body 2 including a terminal receiving chamber 5 for 
receiving a male terminal 12 crimped on the right-hand end part of a cable 
13, a connector receiving chamber 6 for receiving a male connector 21 to 
be described later, a double engagement member 3 for bringing the male 
terminal 12 received in the terminal receiving chamber 5 in double 
engagement with the female connector 1, and a pair of thin-walled hinges 4 
for integrally connecting the housing main body 2 to the double engagement 
member 3. 
The housing main body 2 is designed in the substantially box-shaped 
configuration of which opposite ends are kept open to the outside. A 
housing lance 11 serving as a primary engagement member for the male 
terminal 12 is disposed on the inner surface of an upper wall 2a of the 
terminal receiving chamber 5 having a height smaller than that of the 
connector receiving chamber 6 for receiving the male connector 21, while a 
pair of engagement protuberances 7 are disposed on the opposite side walls 
2b of the housing main body 2 on the male terminal inserting side for 
holding the double engagement member 3 in the locked state. 
The double engagement member 3 is designed such that side plates 3b each 
having an engagement recess 8 formed thereon are bent inward of a 
substantially inverted U-shaped plate portion 3a at a right angle relative 
to the latter along the opposite side edges of the same, and a base end 
edge 3c of the plate portion 3a located opposite to an open end edge of 
the plate portion 3a and having a cutout 10 formed for allowing a cable to 
pass therethrough is connected to a lower wall 2c of the terminal 
receiving chamber 5 via a pair of thin-walled hinges 4 such that the plate 
3 is detachably fitted to an opening portion of the terminal receiving 
chamber 5. 
The thin-walled hinges 4 are prepared in the form of a pair of rectangular 
band-shaped pieces for connecting the base end edge 3c of the plate 3a to 
the lower wall 2c of the housing main body 2 on the male terminal 
inserting side. To assure that opening and closing of the double 
engagement member 3 are not obstructed, each thin-walled hinge 4 has a 
small thickness so as to enable it to be deflected with a very low 
intensity of power. As is best seen in FIG. 2, each thin-walled hinge 4 
extends from the connecting portion on the lower wall 2c side to the 
connecting portion on the plate 3 side with a constant thickness while 
gradually reducing a width thereof. Specifically, as shown in FIG. 2, each 
thin-walled hinge 4 is dimensioned to have a width W.sub.1 on the housing 
main body 2 side larger than a width W.sub.2 on the double engagement 
member 3 side. 
With such construction, since a sectional area of each thin-walled hinge 4 
measured in the transverse direction varies in proportion to the bending 
moment exerted on the thin-walled hinge 4 as the latter extends in the 
longitudinal direction (in the vertical direction as seen in FIG. 2), a 
constant bending stress appears on the thin-walled hinge 4 in the 
longitudinal direction (i.e., in direction coincident with the bending 
direction), and at this time, the thin-walled hinge 4 serves as a fulcrum 
for turning movement thereof induced as the double engagement member 3 is 
opened or closed. Thus, the thin-walled hinge 4 is smoothly deformed while 
exhibiting a constant curved contour without any concentration of the 
bending power at a specific location when the bending moment is exerted on 
the thin-walled hinge 4 due to the turning movement of the latter. At this 
time, it is not necessary to reduce the thickness of the thin-walled hinge 
4 in excess of a preset level. Consequently, there do not arise 
malfunctions that the thin-walled hinge 4 is sharply bent at the position 
offset from the central part thereof as seen in the longitudinal 
direction, and moreover, the fulcrum of the thin-walled hinges 4 is 
dislocated from a predetermined position. It should be noted that the 
thin-walled hinges 4 may be designed such that the width of each 
thin-walled hinge 4 may be dimensioned to be continuously reduced from the 
connecting portion on the plate portion 3a side toward the lower wall 2c 
side. 
Primary engagement of the male terminal 12 with the female connector 1 is 
achieved by way of the steps of first inserting the male terminal 12 into 
the terminal receiving chamber 5 of the housing main body 2 so as to allow 
an electrical contact portion 16 of the male terminal 12 to be engaged 
with a stepped part 5a formed on a lower wall 2c of the terminal receiving 
chamber 5 for preventing the male terminal 12 from being disconnected from 
the female connector 1 in the forward direction, and subsequently, 
bringing an engagement portion 14 formed on the upper surface of the 
electrical contact portion 16 at the rear end of the latter in engagement 
with the housing lance 11 disposed on the inner surface of the upper wall 
2a of the terminal receiving chamber 5. 
Next, as shown in FIG. 3, double engagement of the male terminal 12 with 
the female connector 1 is achieved by way of the steps of first closing an 
opening portion of the terminal receiving chamber 5 with the double 
engagement member 3 with the aid of the thin-wailed hinges 4, receiving 
the engagement protuberances 7 on the housing main body 2 in the 
engagement recesses 8 on the side plates 3b in the locked state, and 
engaging the rear end edge of a cable sheath caulking portion 15 of the 
male terminal 12 with an engagement stepped part 9 formed along the cable 
insert cutout portion 10. 
At this time, the thin-walled hinges 4 are deformed while exhibiting a 
predetermined curved contour without any occurrence of a malfunction that 
they are sharply bent at the positions offset from the central parts 
thereof as seen in the longitudinal direction, causing the fulcrum for 
turning movement of the thin-walled hinges 4 to be dislocated from a 
predetermined position. Consequently, since the engagement protuberances 7 
can be received in the engagement recesses 8 at the predetermined correct 
positions at all times, and moreover, the engagement stepped part 9 can be 
engaged with the rear end edge of the cable sheath caulking portion 15 at 
the predetermined correct position at all times, it is assured that the 
double engagement member 3 can easily and reliably be secured to the 
housing main body 2 in the locked state. This leads to the result that an 
operation for assembling the male terminal 12 with the female connector 1 
can be performed at an improved efficiency. 
In addition, since there do not arise malfunctions that the thin-walled 
hinges 4 are sharply bent, causing breakage to readily occur at the 
sharply bent parts of the thin-walled hinges 4, and moreover, operator's 
fingers are liable to collide against the sharply bent parts each having 
an acute angle, the female connector 1 exhibits excellent appearance on 
completion of the assembling operation. 
FIG. 4 is a vertical sectional view of a structure employable for a 
thin-walled hinge constructed according to another embodiment of the 
present invention, particularly showing a female connector including a 
double engagement member to be secured thereto via the thin-walled hinge, 
and FIG. 5 is a front view of the structure shown in FIG. 4. Also in this 
embodiment, a male terminal is inserted into the female connector 
constructed in the substantially same manner as that in the preceding 
embodiment. 
As shown in FIG. 4, in this embodiment, a female connector 21 is composed 
of a terminal receiving chamber 25 for receiving a male terminal 32 
crimped on the left-hand end part of a cable 33, a terminal insert opening 
portion 26 for inserting a male terminal (not shown) into the female 
connector 21 after the male terminal 32 is inserted into the female 
connector 21, a housing main body 22 including a connector locking unit 
30, a double engagement member 23 for bringing the male terminal 32 
received in the terminal receiving chamber 25 in double engagement with 
the female connector 21, and a thin-walled hinge 24 for firmly connecting 
the double engagement member 23 to the housing main body 22. 
The housing main body 22 is designed in the substantially box-shaped 
configuration of which opposite ends are kept open to the outside. A 
housing lance 31 serving as a primary engagement member is disposed on the 
inner surface of an upper wall 22a of the terminal receiving chamber 25, 
while a pair of engagement recesses 27 are formed on side walls 22b on the 
male terminal insert side for holding the double engagement member 23 in 
the locked state with the aid of the engagement recesses 27. 
A pair of engagement protuberances 28 are disposed on the opposite side 
surfaces of the double engagement member 23 having a substantially 
U-shaped sectional contour, and a base end portion 23a of the double 
engagement member 23 is connected to a lower wall 22c of the terminal 
receiving chamber 25 on the male terminal insert side via the thin-walled 
hinge 4 so as to enable the double engagement member 23 to be detachably 
fitted into an opening portion of the terminal receiving chamber 25. 
The thin-walled hinge 24 is designed in the form of a rectangular 
band-shaped piece for connecting the base end portion 23a of the double 
engagement member 23 to the lower wall 22c of the terminal receiving 
chamber 25 on the male terminal insert side. To assure that opening and 
closing of the double engagement member 23 are not obstructed by the 
thin-walled hinge 24, a thickness of the thin-walled hinge 24 is preset to 
be small in order to assure that the thin-walled hinge 24 can be deflected 
with a very low intensity of power, and the thin-walled hinge 24 is molded 
such that the width of each thin-walled hinge 24 is continuously reduced 
from the lower wall 22c of the female connector 21 toward the base end 
portion 23a thereof while a constant thickness of each thin-walled hinge 
24 is maintained therebetween. 
With this construction, since a sectional area of the thin-walled hinge 24 
as measured in the transverse direction varies in the longitudinal 
direction in proportion to the bending moment exerted on the thin-walled 
hinge 24 in the same manner as the thin-walled hinges 4 in the preceding 
embodiment, a constant stress appears on the thin-walled hinge 24 in the 
longitudinal direction (i.e., in the direction coincident with the bending 
direction). Thus, the thin-walled hinge 24 is smoothly deformed with a 
predetermined curved contour not only without any necessity for reducing 
the thickness of the thin-walled hinge 24 in excess of a predetermined 
level but also without any possibility that the bending power is 
concentratively applied to a specific location on the thin-walled hinge 24 
when the bending moment is exerted on the thin-walled hinge 24. 
Consequently, there does not arise a malfunction that the thin-walled 
hinge 24 is not bent at the central part thereof 24 as seen in the 
longitudinal direction but it is sharply bent at the position offset away 
from the foregoing central part, resulting in the fulcrum for turning 
movement of the thin-walled hinge 24 being dislocated from the original 
position. 
Primary engagement of the male terminal 32 with the female connector 21 is 
achieved by way of the steps of first inserting the male terminal 32 into 
the terminal receiving chamber 25 of the housing main body 22, bringing 
the foremost end of an electrical contact portion 36 of the male terminal 
36 in contact with a stepped part 25a formed in the terminal receiving 
chamber 25 for preventing the male terminal 32 from being disconnected 
from the female connector 21 in the forward direction, and subsequently, 
bringing an engagement hole 34 formed through the upper surface of the 
electrical contact portion 36 of the male terminal 32 in engagement with 
the housing lance 31 disposed on the inner surface of the upper wall 22a 
of the terminal receiving chamber 25. 
Next, double engagement is achieved by way of the steps of fitting the 
double engagement member 23 into an opening portion of the terminal 
receiving chamber 25 via the thin-walled hinge 24, receiving the 
engagement protuberances 28 in the engagement recesses 27 on the double 
engagement member 23 in the locked state, and bringing a pair of 
engagement protuberances 29 on the double engagement member 23 in 
engagement with the rear end edge of a cable sheath caulking portion 35 of 
the male terminal 32. 
At this time, since the thin-walled hinge 24 is deformed with a 
predetermined curved contour and the fulcrum for turning movement of the 
thin-walled hinge 24 is not dislocated from the original position because 
the thin-walled hinge 24 is not sharply bent at the position offset away 
from the central part of the latter as seen in the longitudinal direction, 
the engagement protuberances 28 can be engaged with the engagement 
recesses 27 at the predetermined positions at all times, and moreover, the 
engagement protuberances 29 can likewise be engaged with the rear end edge 
of the cable sheath caulking portion 35 of the male terminal 32 at the 
predetermined positions at all times. Thus, it is assured that the double 
engagement member 23 can reliably be fitted to the housing main body 22 in 
the locked state. 
Consequently, an operation for assembling the male terminal 32 with the 
female connector 21 can be performed at an improved efficiency while the 
same advantageous effects as those of the male connector 1 in the 
preceding embodiment are unchangeably maintained with the aforementioned 
structure employable for the thin-walled hinge 24. 
It should of course be understood that the present invention should not be 
limited only to the aforementioned two embodiments but adequate change or 
modification may be made with respect to the contour of each thin-walled 
hinge and the number of thin-walled hinges as desired. 
While the present invention has been described above with respect to the 
thin-walled hinge(s) for connecting the double engagement member to the 
housing main body of the female connector, the present invention may 
equally be applied to various kinds of components each including a 
structure employable for a thin-walled hinge serving as a fulcrum for 
turning movement of the relevant component in the case that two components 
to be detachably combined with each other are integrally connected to each 
other and disconnected from each other. 
As is apparent from the above description, according to the present 
invention, since each thin-walled hinge has a structure wherein the width 
of each thin-walled hinge is continuously reduced from the connecting 
portion of one component from the connecting portion of other component 
while the thin-walled hinge maintains a constant thickness therebetween, 
the sectional area of each thin-walled hinge measured in the transverse 
direction varies in proportion to a magnitude of bending moment exerted on 
the thin-walled hinge. Thus, in the case that two components are connected 
to each other and disconnected from each other, a constant bending stress 
uniformly appears in the longitudinal direction (i.e., in the direction 
coincident with the bending direction) of the thin-walled hinge. 
Consequently, when the bending moment is exerted on each thin-walled 
hinge, the latter can smoothly be deformed with a constant curved contour 
not only without any necessity for reducing the thickness of each 
thin-walled hinge in excess of a predetermined level, resulting in the 
strength of the thin-walled hinge being reduced but also without any 
possibility that the bending power is concentratively exerted on the 
thin-walled hinge. 
Conclusively, the present invention can provide a structure employable for 
a thin-walled hinge(s) which assures that there does not arise a 
malfunction that each thin-walled hinge is undesirably bent and that an 
operation for connecting two components to each other and disconnected 
from each other can be performed at an improved efficiency.