U.S. patent application number 09/863365 was filed with the patent office on 2001-12-20 for lid opening-closing supporting mechanism and storage device using the same.
Invention is credited to Hirose, Akihiko, Ichimaru, Takahide.
Application Number | 20010052524 09/863365 |
Document ID | / |
Family ID | 26592849 |
Filed Date | 2001-12-20 |
United States Patent
Application |
20010052524 |
Kind Code |
A1 |
Ichimaru, Takahide ; et
al. |
December 20, 2001 |
Lid opening-closing supporting mechanism and storage device using
the same
Abstract
A lid opening-closing supporting mechanism in a biaxial rotating
system of the invention is formed of a base shaft, a rotating
member axially supported by the base shaft, a guide hole bored in a
container, a branch hole branching from the guide hole, and first
and second slide shafts attached to a lid and located in the guide
hole. In case coefficient of friction between the second slide
shaft and an inner surface of the guide hole is defined as .mu.,
and an angle formed between a line connecting the base shaft with
the first slide shaft and a line connecting the base shaft with the
second slide shaft is defined as .alpha., the base shaft, the first
slide shaft and the second slide shaft are arranged to satisfy a
formula expressed as .alpha..gtoreq.2.mu. tan.sup.-1. Also, the
first slide shaft may tightly contact an end portion of the guide
hole, while the first and second slide shafts loosely contact the
guide hole in other areas.
Inventors: |
Ichimaru, Takahide;
(Sagamihara-shi, JP) ; Hirose, Akihiko; (Zama-shi,
JP) |
Correspondence
Address: |
KANESAKA AND TAKEUCHI
1423 Powhatan Street
Alexandria
VA
22314
US
|
Family ID: |
26592849 |
Appl. No.: |
09/863365 |
Filed: |
May 24, 2001 |
Current U.S.
Class: |
220/815 ;
220/836 |
Current CPC
Class: |
B65D 2251/1008 20130101;
B60N 2/793 20180201; B65D 43/164 20130101; B60N 3/102 20130101 |
Class at
Publication: |
220/815 ;
220/836 |
International
Class: |
B65D 043/16 |
Foreign Application Data
Date |
Code |
Application Number |
May 30, 2000 |
JP |
2000-159434 |
Nov 17, 2000 |
JP |
2000-350449 |
Claims
What is claimed is:
1. A supporting mechanism for opening and closing a lid for a base
member, comprising: a base shaft attached to the base member, a
rotating member axially supported by the base shaft and rotating
around the base member, a guide hole in a circular arc shape formed
in a side wall of the base member along a rotation track of the
rotating member, a branch hole branching from the guide hole and
formed in the side wall of the base member, a first slide shaft
fixed to the lid, said first slide shaft passing through the guide
hole and axially supported by the rotating member, and a second
slide shaft fixed to the lid, said second slide shaft being located
at the branch hole in a lid closed condition and being located at
the guide hole in a lid open condition, wherein when a coefficient
of friction between the second slide shaft and an inner surface of
the guide hole is defined as .mu. and an angle formed by a line
connecting the base shaft and the first slide shaft and a line
connecting the base shaft and the second slide shaft is defined as
.alpha., the rotating member, the first slide shaft and the second
slide shaft are arranged to satisfy a formula expressed as
.alpha..gtoreq.2.mu. tan.sup.-1.
2. A supporting mechanism according to claim 1, wherein in the lid
closed condition for the base member, the first slide shaft is
located at one end limit of the guide hole while the second slide
shaft is located at a distal end portion of the branch hole, said
lid being rotated in an opening direction from the closed condition
such that the lid is rotated for a predetermined angle around the
first slide shaft to allow the second slide shaft to move from the
distal end portion of the branch hole to the guide hole, and said
first slide shaft and the second slide shaft are moved in the guide
hole to allow the second slide shaft to reach the other end limit,
said rotating member and the lid being rotated around the base
shaft; and said the lid in the open condition is rotated in a
closing direction such that the first slide shaft and the second
slide shaft are moved to allow the first slide shaft to reach the
one end limit while the rotating member and the lid are rotated
around the base shaft, and when the first slide shaft reaches the
one end limit, the second slide shaft enters the branch hole to be
moved to a distal end side of the branch hole while the lid is
rotated around the first slide shaft to thereby close the lid.
3. A supporting mechanism according to claim 1, further comprising
urging means for urging the lid near the second slide shaft toward
an outer side of the guide hole so that said urging means urges a
rotating movement of the lid for more than a predetermined angle at
a time of opening and closing, and the closed condition and the
open condition of the lid are maintained by an urging force of the
urging means.
4. A supporting mechanism according to claim 1, wherein an inner
surface of the guide hole is formed of an
acrylonitrile-butadiene-styrene resin, and said second slide shaft
is formed of metal, said angle expressed as a being 44 degrees or
more.
5. A supporting mechanism according to claim 1, wherein said base
member is a container to be mounted on an automobile and operating
as one of a storage and a cup holder.
6. A supporting mechanism for opening and closing a lid for a base
member, comprising: a base shaft attached to the base member, a
rotating member axially supported by the base shaft and rotating
around the base member, a guide hole in a circular arc shape formed
in a side wall of the base member along a rotation track of the
rotating member, a branch hole branching from the guide hole and
formed in the side wall of the base member, a first slide shaft
fixed to the lid, said first slide shaft passing through the guide
hole and axially supported by the rotating member, and a second
slide shaft fixed to the lid, said second slide shaft being located
at the branch hole in a lid closed condition and being located at
the guide hole in a lid open condition, wherein said guide hole has
an end portion receiving the first slide shaft at a time of closing
the lid, said end portion having a width closely contacting the
first shaft, said guide hole having a width at portions other than
the end portion loosely engaging the first and second slide
shafts.
7. A storage device, comprising: a container including an opening,
a side wall, a base shaft provided on the side wall, a guide hole
formed in the side wall and having a circular arc shape around the
base shaft, and a branch hole formed in the side wall to branch
from the guide hole and having a circular arc shape, an arm axially
supported by the base shaft, and a lid for covering the opening of
the container including a first slide shaft disposed in the guide
hole and engaging the arm, and a second slide shaft to be able to
enter the guide hole and the branch hole, at least one part of the
lid being accommodated inside the container at a time of opening
the lid, wherein said guide hole has an end portion receiving the
first slide shaft at a time of closing the lid, said end portion
having a width closely contacting the first shaft, said guide hole
having a width at portions other than the end portion loosely
engaging the first and second slide shafts.
8. A storage device according to claim 7, wherein said branch hole
has the width same as that of the guide hole other than the end
portion.
9. A storage device according to claim 8, wherein when the first
slide shaft is located at the end portion, the second slide shaft
can slide loosely in the blanch hole.
Description
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
[0001] The present invention relates to a lid opening-closing
supporting mechanism, which is suitably used as a mechanism for
opening and closing a lid for an opening section of a container for
an automobile, such as a storage and a cup holder. The present
invention also relates to a storage device using the lid opening
and closing supporting mechanism.
[0002] Heretofore, a container, such as a cup holder or a storage,
has been installed at a center console or the like of an
automobile, and in this kind of container, a lid for opening and
closing an opening section of the container has been provided.
[0003] As the lid to be used in the container, there is generally
used a lid which has an end rim portion rotatably attached to an
end rim of a container main body, and opens/closes in a flap
system. Therefore, for a portion responding to a rotating track at
a distal end of the lid according to opening and closing of the
lid, it is necessary to have a space above a container main body.
Also, it is necessary to have a space at one end side of the
container main body, for positioning a lid in case the lid is in a
fully open condition with respect to the container main body.
Therefore, in a conventional container having a lid, it is not easy
to obtain an installation location in an automobile in which a
space is limited.
[0004] In order to solve the aforementioned problem, there has been
proposed a lid opening-closing supporting mechanism shown in FIGS.
1 through 3(D) as disclosed in Japanese Patent Publication (KOKAI)
No. H8-156698. As shown in FIGS. 1 and 2, in the lid
opening-closing supporting mechanism, a rotating member 2 is
axially supported by a shaft 11 projected on an outer surface of a
container main body 1, and a guide or slide hole 12 which is formed
in a circular arc shape along a rotating track of the rotating
member 2 and a branch hole 13 which branches outwardly from the
guide hole 12 are formed at a side surface of the container main
body 1. Then, a first slide shaft 31 provided at each of two side
portions (only one is shown in the figures) of a lid 3 is axially
attached to the rotating member 2 by inserting the first slide
shaft 31 from an inside of the container main body 1 through the
guide hole 12, and a second slide shaft 32, which is arranged
parallel to the first slide shaft 31 at each of the two side
portions (only one is shown in the figures) of the lid 3 is
inserted from the inside of the container main body 1 through the
guide hole 12 into a notched groove 21 formed in the rotating
member 2. Incidentally, the lid 3 is urged by a torsion spring s
attached between a projection 14, which is provided between the
guide hole 12 and the rotating shaft 11, and the second slide shaft
32.
[0005] Operations for opening and closing the lid 3 by the lid
opening-closing supporting mechanism are as shown in FIGS. 3(A)
through 3(D).
[0006] Under a closed condition where an opening section of the
container main body 1 is closed by the lid 3, as shown in FIG.
3(A), the first slide shaft 31 is positioned at one end limit
(upper left limit in the figure) of the guide hole 12, and also,
the second slide shaft 32 is positioned at a distal end portion of
the branch hole 13, wherein the lid 3 is urged toward a closing
direction by the torsion spring s (not shown in FIGS. 3(A) through
3(D) but referred thereto hereinafter), to thereby maintain the
closed condition.
[0007] By rotating the lid 3 toward an opening direction, that is,
toward an upper right side in FIG. 3(A) from the closed condition
while resisting against the urging force of the torsion spring s,
as shown in FIG. 3(B), the lid 3 is rotated for a predetermined
angle around the first slide shaft 31, and the second slide shaft
32 is moved from the distal end portion of the branch hole 13 to
the guide hole 12. Then, as shown in FIG. 3(C), the first slide
shaft 31 and the second slide shaft 32 are moved toward the other
end side (lower right side in the figures) in the guide hole 12,
and at the same time, the rotating member 2 is rotated around the
rotating shaft 11, so that the lid 3 is rotated in the opening
direction around the rotating shaft 11. Accordingly, as shown in
FIG. 3(D), the second slide shaft 32 abuts against the other end
limit of the guide hole 12, i.e. a slide limit or limit of rotating
the lid, and the opening section of the container main body is
opened. In this case, at the time of operation from FIG. 3(B) to
FIG. 3(D), the urging force of the torsion spring s acts in the
direction of rotating the lid 3 in the opening direction, so that
the lid is rotated automatically by the urging force, and the fully
opened condition in FIG. 3(D) is maintained.
[0008] Also, in case of closing the lid 3 in the opened condition
in FIG. 3(D), by rotating the lid 3 in the above opened condition
toward a closing direction (upper left side in the figure) while
resisting against the urging force of the torsion spring s, as
shown in FIG. 3(C), the first slide shaft 31 and the second slide
shaft 32 are firstly moved to the one end side in the guide hole
12, and the rotating member 2 is rotated around the rotating shaft
11, so that the lid 3 is rotated for a predetermined angle around
the rotating shaft 11. Then, as shown in FIG. 3(B), when the first
slide shaft 31 reaches the one end limit of the guide hole 12, the
second slide shaft 32 moves from the guide hole 12 into the branch
hole 13 to move toward the distal end of the branch hole 13, as
shown in FIG. 3(A) while the lid 3 is rotated around the first
slide shaft 31 to close the opening section of the container main
body 1. In this case, at the time of the operation shown in FIG.
3(B) to the operation shown in FIG. 3(A), the urging force of the
torsion spring s acts in the direction of rotating the lid 3 in the
closing direction, so that the lid is rotated automatically by the
urging force, and also, the closed condition in FIG. 3(A) is
maintained by the urging force.
[0009] As described above, the aforementioned lid opening-closing
supporting mechanism has been made such that two shafts, i.e. the
first slide shaft 31 and the rotating shaft 11, are used as
rotating shafts for rotating the lid 3, so that a space required
for opening and closing the lid is reduced, and the installation
location can be easily obtained.
[0010] However, in the lid opening-closing supporting mechanism
described above, at the time of operations for opening or closing
the lid 3, a large friction is caused between the second slide
shaft 32 and the guide hole 12. Namely, in case of opening the lid
3, as shown in FIG. 4, a reaction of a force F1 in the opening
direction applied to the lid 3 acts such that the second slide
shaft 32 is rotated around the first slide shaft 31 in a direction
A1 in the figure, and the second slide shaft 32 slidingly moves in
the guide hole 12 while being pushed against an inner peripheral
surface of a lower side of the guide hole 12. On the other hand, in
case of closing the lid 3, a reaction of a force F2 in the closing
direction applied to the lid 3 acts such that the second slide
shaft 32 is rotated around the first slide shaft 31 in a direction
B1 in the figure, and the second slide shaft 32 moves slidingly in
the guide hole 12 while being pushed against an inner peripheral
surface of an upper side of the guide hole 12. Therefore, at the
time of operations for opening and closing the lid 3, a large
operation load is applied to the lid 3, so that in case the lid 3
is rotated manually, there is an uneven feeling, or the smooth
operation can not be obtained at the time of rotation by the urging
force of the torsion spring s.
[0011] Thus, in the opening-closing supporting mechanism, it is
necessary to apply a grease for lubrication to the second slide
shaft 32 or the inner peripheral surface of the guide hole 12, so
as to decrease a frictional resistance between the second slide
shaft 32 and the guide hole 12. Therefore, assembly work of the lid
3 with the container main body 1 is made cumbersome, and a cost
therefor is increased. Also, the grease might contaminate the
surroundings.
[0012] The present invention has been made in view of the
foregoing, and an object of the invention is to provide a lid
opening-closing supporting mechanism of a biaxial or two-shaft
rotating system, in which a frictional resistance at the time of
operations for opening and closing the lid is decreased, so that
smooth opening and closing operations can be carried out without
using a lubricant, such as a grease.
[0013] Further objects and advantages of the invention will be
apparent from the following description of the invention.
SUMMARY OF THE INVENTION
[0014] To achieve the aforementioned object, the present invention
provides a supporting mechanism for opening and closing a lid. The
supporting mechanism is formed of a rotating or base shaft attached
to an outer surface of a base member to be opened and closed, such
as a container; a rotating member axially supported by the rotating
shaft and rotating along the outer surface of the member to be
opened and closed; a guide hole in a circular arc shape bored in a
side surface of a container main body along a rotating track of the
rotating member; a branch hole branching from the guide hole and
bored in the side surface of the container main body; a first slide
shaft formed on a lid for opening and closing an opening section of
the base member, in which the first slide shaft passes through the
guide hole from an inside of the base member and is axially
supported by the rotating member; and a second slide shaft formed
on the lid and inserted into the guide hole from the inside of the
base member.
[0015] Under a closed condition in which the opening section of the
base member is closed by the lid, the first slide shaft is located
at one end limit of the guide hole, and also, the second slide
shaft is located at a distal end portion of the branch hole. Then,
by rotating the lid in the closed condition toward an opening
direction, firstly, the lid is rotated for a predetermined angle
around the first slide shaft, and the second slide shaft is moved
from the distal end portion of the branch hole to the guide hole.
Then, the first slide shaft and the second slide shaft are moved in
the guide hole to the other end side thereof, and the rotating
member is rotated around the rotating shaft, so that the lid is
rotated around the rotating shaft to open the opening section of
the base member.
[0016] Also, by rotating the lid in the opened condition toward a
closing direction, firstly, the first slide shaft and the second
slide shaft are moved to the one end side in the guide hole, and
also, the rotating member is rotated around the rotating shaft, so
that the lid is rotated for a predetermined angle around the
rotating shaft. After the first slide shaft reaches the
aforementioned one end limit of the guide hole, the second slide
shaft enters the branch hole from the guide hole to be moved to the
distal end side of the branch hole, so that the lid is rotated
around the first slide shaft to thereby close the opening section
of the base member.
[0017] In the lid opening-closing supporting mechanism as
structured above, in case a coefficient of friction between the
second slide shaft and an inner surface of the guide hole is
defined as .mu. and an angle formed by a line connecting the
rotating shaft and the first slide shaft and a line connecting the
rotating shaft and the second slide shaft is defined as .alpha.,
the rotating member, the first slide shaft and the second slide
shaft are arranged to satisfy a formula expressed as
.alpha..gtoreq.2.mu. tan.sup.-1.
[0018] A second embodiment of the invention is a storage device,
which is formed of a box member or container having a guide hole
formed in a circular arc shape around a base shaft on a side wall
of the container, and a branch hole formed in a circular arc shape
branching from the guide hole; a lid provided for covering an
opening of the box member and having a first shaft engaging the
guide hole at the time of closing, and a second shaft engaging the
branch hole; and an arm connecting between the base shaft and the
first shaft. In the storage device structured as described above,
at the time of opening the lid, at least one part of the lid is
accommodated inside the box member. A groove width of the guide
hole at a portion receiving the first shaft at the time of closing
the lid has a size relatively tightly engaging the first shaft. The
other portions of the guide hole have a width for receiving the
first shaft and the second shaft relatively loosely.
[0019] Accordingly, by merely increasing the accuracy of the part
of the groove, a rigidity under the closed condition of the lid and
a smoothness at the time of opening and closing operations can be
achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a side view showing an example of a container
using a conventional lid opening-closing supporting mechanism of a
biaxial rotating system;
[0021] FIG. 2 is an enlarged view of a part of the lid
opening-closing supporting mechanism of the biaxial rotating system
shown in FIG. 1;
[0022] FIGS. 3(A) through 3(D) are explanatory views for explaining
operations of the opening-closing supporting mechanism of FIGS. 1
and 2;
[0023] FIG. 4 is an explanatory view for explaining a dynamical
relationship of an opening-closing supporting mechanism and set
conditions of the present inventions;
[0024] FIG. 5 is a graph showing results of experiments conducted
in an embodiment; and
[0025] FIG. 6 is an explanatory view showing a second embodiment of
the invention, in which a relationship between a guide groove and a
shaft is shown.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] Hereunder, embodiments of the invention will be explained
with reference to the attached drawings.
[0027] When a dynamical relation at the time of operations for
opening and closing the lid by a lid opening-closing supporting
mechanism of a biaxial rotating system has been considered, the
followings have been found. That is, by adjusting the positional
relationship among a rotating or base shaft 11, a first slide shaft
31 and a second slide shaft 32 appropriately, the frictional
resistance between the second slide shaft 32 and the guide hole 12
at the time of operations for opening and closing the lid can be
effectively decreased, and the smooth opening and closing
operations can be achieved without using a lubricant, such as a
grease, in accordance with the setting of the positional
relationship.
[0028] Namely, in FIG. 4, in case a load F2 for rotating the lid 3
in the closing direction is applied, a load in a direction A2 in
the figure is applied to the first slide shaft 31, and a load in a
direction B1 in the figure is applied to the second slide shaft 32.
At this time, a coefficient .mu. of friction between the second
slide shaft 32 and the guide hole 12 is shown as follows from a
formula of an angle of friction:
.mu.=tan .theta.
[0029] In this case, .theta. is an angle formed by a straight line
C connecting between the rotating shaft 11 and the second slide
shaft 32, and the loading direction B1. Then, the aforementioned
angle .theta. is shown as follows:
.theta.=.mu. tan.sup.-1
[0030] In this case, layout of the rotating shaft 11, the first
slide shaft 31 and the second slide shaft 32 is set such that an
angle .alpha. formed by a straight line D connecting between the
rotating shaft 11 and the first slide shaft 31, and the straight
line C connecting between the rotating shaft 11 and the second
slide shaft 32 becomes more than twice. Namely, the angle .alpha.
satisfies the following:
.alpha..gtoreq.2.mu. tan.sup.-1
[0031] As a result, the lid 3 is rotated smoothly without causing
the uneven feeling or rugged feeling, and the lid 3 is extremely As
a result, the lid 3 is rotated smoothly without causing the
smoothly moved in case of rotating the lid 3 by the urging means,
such as a torsion spring, resulting in finding that a use of the
grease can be abolished.
[0032] For instance, in case the second slide shaft 31 is formed of
metal and the slide hole 12, i.e. container main body 1, is formed
of an acrylonitrile-butadiene-styrene (ABS) resin, coefficient .mu.
of friction is approximately 0.4, and
2.mu. tan.sup.1=43.6
[0033] Thus, in this case, by setting the arrangements of the
rotating shaft 11, the first slide shaft 31 and the second slide
shaft 32 such that the angle .alpha. is 43.6 degrees or more, and
realistically, the angle .alpha. is 44 degrees or more, the
extremely smooth rotating operation of the lid 3 can be obtained
without using the grease. Incidentally, more preferable value of
the angle .alpha. is 50 degrees.
[0034] Incidentally, although the present invention enables to
abolish the use of the grease, the present invention does not
preclude the lubricant, such as grease. Even if the lubricant is
used, the present invention can make the arrangement of the
rotating shaft 11, the first slide shaft 31 and the second slide
shaft 32 appropriate.
[0035] Namely, for example, in the combination of the second slide
shaft 32 made of metal and the guide or slide hole 12, i.e.
container main body 1, made of ABS resin, in case the coefficient
.mu. of friction is about 0.1, it is found that 2.mu.
tan.sup.-1=11.4. By setting the aforementioned angle .alpha. to be
11.4 degrees or more, and realistically, 12 degrees or more, the
smooth rotating motion of the lid 3 can be achieved. In this case,
a distance between the two shafts, that is, between the first slide
shaft 31 and the second slide shaft 32, can be set much narrower,
so that the design can be made more freely. In the present
invention, the degree of freedom in design can be definitely
obtained.
[0036] The aforementioned lid opening-closing supporting mechanisms
shown in FIG. 4 were made, and by variously modifying relative
positions of the first slide shaft 31 and the second slide shaft 32
and by variously settings the angle .alpha., experiments for
evaluating the opening and closing motions of the lid 3 without
using the grease were carried out. The results thereof are shown in
FIG. 5.
[0037] Incidentally, the first slide shaft 31 and the second slide
shafts 32 were made of metal, and the container main body 1
including the slide hole 12 and the lid 3 were made of ABS resin.
Therefore, the coefficient .mu. of friction is approximately 0.4,
and 2.mu. tan.sup.-1 is 43.6.
[0038] As shown in FIG. 5, in a set region or area in which the
angle .alpha. is 44 degrees or more, the operation load is small,
and the rotating motion is smooth without having uneven feeling,
and it is confirmed that there is no need to use the grease.
[0039] Also, the materials for the second slide shaft 32 and the
slide hole 12, i.e. container main body 1, are not limited to the
combination of metal and ABS resin, and can be a combination of
metal members, a combination of synthetic resins, and a combination
of different synthetic resins.
[0040] Furthermore, although the embodiment of the invention has
been explained as the supporting mechanism for opening and closing
the lid of the container, such as a cup holder or a storage
installed in the automobile, the supporting mechanism for opening
and closing of the invention is not limited thereto, and the
present invention can be used for lids which open and close opening
sections of various kinds of members to be opened and closed.
[0041] Still further, the torsion spring s or urging means for
urging the lid 3 can be omitted, and shapes and structures of the
container main body 1 (member to be opened and closed), the
rotating member 2 and the lid 3 are not limited to those shown in
FIGS. 1 through 4, and can be adequately modified within the gist
of the present invention.
[0042] As described above, according to the lid opening-closing
supporting mechanism of the first embodiment of the invention, in
the lid opening-closing supporting mechanism of the biaxial
rotating system which can achieve the reduction of the installation
space, the arrangements of the shafts can be easily adjusted
appropriately, and the smooth opening and closing motions can be
definitely achieved, so that the use of the grease can be abolished
or eliminated.
[0043] Therefore, a step of applying the grease or the like can be
eliminated to thereby reduce the cost thereof, and at the same
time, contamination of the surroundings by the grease can be surely
prevented.
[0044] Hereunder, a second embodiment of the invention will be
explained in detail with reference to FIG. 6.
[0045] In a lid opening-closing supporting mechanism, a rotating
track of a first slide shaft 31 is defined by an arm 2' having one
end pivotally attached to a rotating or base shaft 11. Also, a
stopping end of the lid 3 is defined at a position where the first
slide shaft 31 abuts against an upper end of a guide hole 12.
Further, a second slide shaft 32 moves within a branch hole 13
around the first slide shaft 31 to define a rotating range V. Then,
a moving track in a rotating range X is defined by the guide hole
12.
[0046] Therefore, in order to obtain a smooth motion without play
at the closing and stopping position of the lid 3 and within the
rotating range V in which the lid 3 is rotated around the first
slide shaft 31, it is preferable that the first slide shaft 31 and
an inner peripheral surface of an upper end portion of the guide
hole 12 are closely and tightly engaged with each other, and the
second slide shaft 32 and the branch hole 13 are loosely engaged
with each other.
[0047] Also, in order to obtain the smooth motion in the rotating
range in which both the first slide shaft 31 and the second slide
shaft 32 are moved along the guide hole 12, it is preferable that
the first and second slide shafts 31, 32 and the guide hole 12 are
loosely engaged with each other.
[0048] From the foregoing, accuracies of the guide holes are set as
follows.
[0049] In order to tightly define three directions, that is, upper,
lower and front sides of the first slide shaft 31 by an upper end
of the guide hole 12, a dimensional tolerance of a region U in FIG.
6 is determined such that the first slide shaft 31 is relatively
closely engaged with the guide hole 12.
[0050] At the time of an opening operation, a slidingly contacting
surface of the second slide shaft 32 with respect to the branch
hole 13 is determined to be an outer periphery side by an operating
force applied to the lid 3, and at the time of a closing operation,
the second slide shaft 32 is allowed not to contact the branch hole
13. Therefore, in the region V in FIG. 6, only smoothness of an
inner surface of the outer periphery side of the branch hole 13 is
considered, and the accuracies of the width of the groove and the
diameter of the shaft are loosely set.
[0051] While moving within a region W in the guide hole 12, since
the track of the first slide shaft 31 can be solely determined by
the arm 2', an accuracy of clearance between the first slide shaft
31 and the guide hole 12 in this region W can be completely
ignored.
[0052] Although the play of the lid 3 within the region X in the
guide hole 12 depends on an engagement clearance or space between
the second slide shaft 32 and the guide hole 12, in accordance with
the operating force for opening and closing applied to the lid 3,
the sliding contact surface of the second slide shaft 32 with
respect to the guide hole 12 is determined to be an inner periphery
side at the time of the opening operation, and the sliding contact
surface of the second slide shaft 32 with respect to the guide hole
12 is determined to be the outer periphery side at the time of the
closing operation. Therefore, as long as the inner surface of the
guide hole 12 is smooth, the specific accuracy is not required for
the width of the groove, so that the accuracy between the width of
the groove and the diameter of the shaft is set loosely. Also,
since a stopper of an opening limit can be made by another member,
the accuracy of the lower end side of the main guide groove 12 may
be low.
[0053] Incidentally, if spring means is provided to elastically
urge the second slide shaft 32 to always abut against one of the
inner surfaces of the guide hole 12, it is sufficient in the region
X to make one of the inner surfaces of the guide hole 12
smooth.
[0054] As described above, according to the second embodiment of
the present invention, the first slide shaft does not have to
contact the guide hole except the time for closing operation, and
the second slide shaft may contact only one of the surfaces of the
guide hole. Thus, the sliding resistance at the time of opening and
closing operations can be extremely reduced. Furthermore, since
there is no need to accord the track of the first slide shaft with
that of the second slide shaft, even though the two shafts pass
through an inside of the common guide hole, the accuracy of the
relative positional relationship between the guide hole and the two
shafts is not necessary to be increased. Therefore, according to
the present invention, the rigidity of the lid in the closed
condition and the smoothness thereof at the opening and closing
operations can be retained, and the great effect can be obtained in
reducing the manufacturing cost.
[0055] While the invention has been explained with reference to the
specific embodiments of the invention, the explanation is
illustrative and the invention is limited only by the appended
claims.
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