Support structure for a toilet cover unit

A toilet seat 40 and a toilet lid 50 are pivotably attached to an attachment base 20 of a western-style toilet bowl 10 with a hinge mechanism 30. The hinge mechanism 30 includes first and second rotational resistance mechanisms 60R and 60L which are respectively mounted on opposing sides of the attachment base 20. First right and left hinge parts 42R and 42L are respectively integrally formed at opposite ends of the toilet seat 40. Second right and left hinge parts 52R and 52L are respectively integrally formed at opposite end part of the toilet lid 50, the first and second support pins 36R and 36L and the caps 38R and 38L. The first rotational resistance mechanism 60R applies rotational resistant force in the lowering of the toilet seat 40 via the first support pin 36R. The second rotational resistance mechanism 60L applies rotational resistant force in the lowering of the toilet lid 50 via the second support pin 36L. The first and second rotational resistance mechanisms 60R and 60L are different in their external configurations and they cannot be attached incorrectly by mistake.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a support structure for a toilet cover 
unit that supports a toilet seat and/or a toilet lid while being raised or 
lowered freely against the toilet bowl main body, and more particularly to 
a hinge mechanism. 
2. Description of the Related Art 
A conventional hinge mechanism of this type supports one end of a toilet 
seat and/or toilet lid so that the seat/lid pivots freely relative to the 
upper part of the western-style toilet bowl. The hinge mechanism includes 
and a rotational resistance mechanism that applies a resistant force to 
pivotal movement of the toilet seat, or the toilet lid, in one direction 
so that the seat/lid descends slowly. The rotational resistance mechanism 
is a mechanism by which the toilet lid in an upright position is pivoted 
slowly when force is applied to the toilet lid in a downward direction. 
Therefore, when the toilet lid leaves the hand, it will not fall rapidly 
with a crash against the upper surface of the toilet seat. The hinge 
mechanism on the toilet seat side also has a similar rotational resistance 
mechanism. 
It is desirable for promotion of common parts that rotational resistance 
mechanisms of a similar constitution are used for the toilet lid and the 
toilet seat, but the rotational resistance mechanisms incorrectly attached 
have caused not only troubles in raising and lowering operations but also 
degradation in durability because the weight of the rotational resistance 
mechanism for the toilet lid is different from that for the toilet seat. 
SUMMARY OF THE INVENTION 
The purpose of the present invention is to provide a support structure for 
a toilet cover unit, which supports a toilet seat and a toilet lid 
respectively with rotational resistance mechanisms which cannot be 
positioned incorrectly. 
The support structure of the present invention for the toilet cover unit 
has a first hinge unit that pivotably supports an end part of a toilet 
seat and a second hinge unit which pivotably supports the toilet lid 
respectively against a main support body secured to the toilet bowl side. 
The features of the support structure include a first hinge unit that 
comprises: a first rotational resistance unit which includes a first shaft 
that is supported so as to pivot with a shaft core as its center and a 
resistance component which applies rotational resistant force against 
rotations of the first shaft in one direction; a first holder part which 
holds the first rotational resistance unit so as to apply a rotational 
resistant force in the lowering of the toilet seat; and a first support 
component that is connected to the first shaft so as to transmit the 
rotational resistant force to the toilet seat. 
The second hinge unit comprises: a second rotational resistance unit which 
includes a second shaft that is supported so as to pivot with a shaft core 
as its center and a resistance component which applies rotational 
resistant force against rotations of the second shaft in one direction; a 
second holder part which holds the second rotational resistance unit so as 
to apply rotational resistant force in the lowering of the toilet lid; and 
a second support component that is connected to the second shaft so as to 
transmit the forenamed rotational resistant force to the toilet lid. 
The first and second rotational resistance units have different external 
configurations and are respectively positioned and secured to the first 
and second holder parts. 
The first hinge unit is located between the main support body and the 
toilet seat and pivotably supports the toilet seat against the main 
support body. The second hinge unit is located between the main support 
body and the toilet lid and pivotably supports the toilet lid against the 
main support body. 
The first hinge unit comprises the first rotational resistance unit. The 
first shaft of the first rotational resistance unit, rotated via the first 
support component with the shaft core as its center when the toilet seat 
is rotated downward, receives rotational resistant force from the 
resistance component. Therefore, the first rotational resistance unit 
operates so that the toilet seat is lowered slowly. Since the resistance 
component applies no rotational resistant force to the first shaft when 
the toilet seat rotates upward, the toilet seat is raised smoothly. The 
second rotational resistance unit of the second hinge unit applies 
rotational resistant force to the toilet lid when the toilet lid is 
rotated downward, in the same way as the first rotational resistance unit 
does, so that the toilet lid is lowered slowly. 
The first rotational resistance unit is positioned at and secured to the 
first holder part on the main support body or on the toilet seat side. 
The second rotational resistance unit is positioned at and secured to the 
second holder part on the main support body or on the toilet lid side. The 
weight of the toilet seat is different from that of the toilet lid. In 
such cases, the rotational resistant force generated by the resistance 
unit of the first rotational resistance unit is required to be set 
different from that of the resistance unit of the second rotational 
resistance unit. 
The first and second rotational resistance units differ from each other in 
their external configurations and also in the configurations of the first 
and second holder parts where they are positioned and secured. Therefore, 
the first rotational resistance unit cannot be attached to the second 
holder part or the second rotational resistance unit cannot be attached to 
the first holder part by mistake. 
The difference in the external configurations of the first and second 
rotational resistance units is most preferably realized without modifying 
the configuration of any other part except for the control components 
which control their rotations. 
Springs, viscous resistance material or other materials can be utilized for 
the respective resistance components of the first and second rotational 
resistance units. The first and second hinge units may have a constitution 
where the toilet seat and the toilet lid are respectively rotated on the 
same shaft core, or another constitution where the toilet seat and the 
toilet lid are respectively rotated on different shaft cores and where the 
shaft of the second hinge unit is arranged at a position above the first 
hinge unit.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 is a perspective view drawing of a western-style toilet bowl from an 
upper rear position. A western-style toilet bowl 10 comprises a bowl part 
12 formed of ceramic or other materials. An attachment base 20 is attached 
to the upper end part of the bowl part 12 with a bolt or such device. A 
toilet seat 40 and a toilet lid 50 are attached to the attachment base 20 
so as to rotate freely via a hinge mechanism 30. 
FIG. 2 is a perspective view drawing showing the state of the toilet seat 
and the toilet lid disassembled at the position of the hinge mechanism. 
The hinge mechanism 30 comprises a first right hinge part 42R and a first 
left hinge part 42L which are respectively integrally formed at either end 
part of the toilet seat 40, a second right hinge part 52R and a second 
left hinge part 52L which are respectively integrally formed at either end 
part of the toilet lid 50, a first rotational resistance mechanism 60R and 
a second rotational resistance mechanism. 60L which are respectively 
mounted at either end part of the attachment base 20, a first support pin 
36R, a second support pin 36L, and caps 38R and 38L. 
The first rotational resistance mechanism 60R applies rotational resistant 
force to the toilet seat 40 via the first support pin 36R. The second 
rotational resistance mechanism 60L applies rotational resistant force to 
the toilet lid 50 via the second support pin 36L. 
The next paragraphs outline the operation of the hinge mechanism 30. The 
toilet seat 40 is assumed to be fully lowered onto the upper surface of 
the bowl part 12 and the toilet lid 50 is also assumed to be fully lowered 
(as in FIG. 1). When the front end of the toilet lid 50 is raised by hand, 
the toilet lid 50 rotates with the hinge mechanism 30 as its center and 
stands upright slightly beyond 90 degrees. The toilet lid 50 receives no 
resistant force from the second rotational resistance mechanism 60L. When 
downward force is applied to the front end of the toilet lid 50 while the 
toilet lid 50 is at the upright position, the toilet lid 50 rotates slowly 
while receiving resistant force from the second rotational resistance 
mechanism 60L. Therefore, when the toilet lid 50 is released from the 
hand, the toilet lid 50 will not drop quickly, crashing against the upper 
surface of the toilet seat 40. 
In the same way, when the front end of the toilet seat 40 is raised by hand 
from the state where the toilet seat 40 is fully lowered onto the upper 
surface of the bowl part 12, the toilet seat 40 also rotates with the 
hinge mechanism 30 as its center and stands upright slightly beyond 90 
degrees. When downward force is applied to the front end of the toilet 
seat 40 while the toilet seat 40 is at the upright position, the toilet 
seat 40 rotates slowly while receiving resistant force from the first 
rotational resistance mechanism 60R. Therefore, the toilet seat 40 also 
will not crash against the upper surface of the bowl part 12. 
The next paragraphs describe in detail the structure of the hinge mechanism 
30 and its peripheral parts. An attachment base 20 includes a main body 
part 22 which has a hollow part 21 and foot parts 23 which are integrally 
formed on either side of a lower part of the main body part 22. 
FIG. 3 is a sectional drawing showing the part where an attachment base 20 
is attached to the western-style toilet bowl 12 with a bolt. Each foot 
part 23 has an attachment hole 23a for securing with a bolt BT. An 
attachment hole 12a is formed in an upper part of the bowl part 12, and an 
elastic sleeve SL of rubber material for mounting a nut NT in the 
attachment hole 12a. Therefore, when the bolt BT is inserted into the 
attachment hole 23a and the elastic sleeve SL is inserted in the foot part 
23 and then tightened with the nut NT. The attachment base 20 is secured 
at the upper-surface end part of the bowl part 12. 
If the bowl part 12 of the western-style toilet bowl is thin, it is 
naturally possible to secure the attachment base 20 by fitting the nut 
from the lower side of the bowl part 12 onto the lower part of the bolt 
inserted into the attachment hole 12a. 
FIG. 4 is a drawing showing the sectional views of both sides of the 
attachment base 20 and also the side views of the first and second 
rotational resistance mechanisms 60R and 60L before being attached to the 
attachment base 20. FIG. 5 is a drawing showing the view in direction A of 
FIG. 4 and FIG. 6 is a drawing showing the view in direction B of FIG. 4. 
FIG. 7 is a drawing showing the state where the first and second 
rotational resistance mechanisms 60R and 60L are attached to the 
attachment base 20. 
The main body part 22 of the attachment base 20 comprises a first storage 
space 25R and a second storage space 25L, on opposite sides of the hollow 
part 21, where the first rotational resistance mechanism 60R and the 
second rotational resistance mechanism 60L are respectively mounted. As 
shown in FIG. 5, the first storage space 25R comprises a round part 25Ra 
which has a round sectional part and a rectangular part 25Rb which extends 
from the lower part of the round part 25Ra and is of almost rectangular 
shape. The width w1 of the rectangular part 25Rb is narrower than the 
diameter d1 of the round part 25Ra, and a vertical member "a" of the 
rectangular part 25Rb is formed parallel to a tangent line of the round 
part 25Ra. Therefore, the first storage space 25R is not symmetrical about 
a center line CL1 which runs through the center of the round part 25Ra. A 
casing 62R of the first rotational resistance mechanism 60R comprises a 
cylindrical main body part 62Ra which has a round sectional shape and a 
rotation stopper part 62Rb which is formed at the lower part of the 
cylindrical main body part 62Ra. The rotation stopper part 62Rb is also 
formed eccentric to the center line CL2 of the cylindrical main body part 
62Ra. 
Therefore, when the first rotational resistance mechanism 60R is inserted 
into the first storage space 25R, the cylindrical main body part 62Ra of 
the casing 62R fits the round part 25Ra of the first storage space 25R and 
the rotation stopper 62Rb fits the rectangular part 25 Rb. As a result, 
the rotation stopper 62Rb acts as rotation stopper against the rotational 
force of the first resistance mechanism 60R. In the same way, the second 
storage space 25L is of almost the same configuration as the first storage 
space 25R and comprises a round part 25La and a rectangular part 25Lb. 
Although the rectangular part 25Lb is also eccentric to the center line of 
the round part 25La, its direction is opposite to that of the first 
storage space 25R. A casing 62L of the second rotational resistance 
mechanism 60L also comprises a cylindrical main body part 62La and a 
rotation stopper 62Lb. The second rotational resistance mechanism 60L 
which is to be mounted by insertion into the second storage space 25L 
cannot be inserted into the first storage space 25R since the position of 
the rotation stopper 62Lb is different. 
As shown in FIGS. 4 through 7, lock mechanisms 26R and 26L are equipped at 
the lower parts of the first and second storage spaces 25R and 25L. The 
lock mechanism 26R comprises a support plate 26Ra which is supported at 
one end by the foot part 23 so as to be elastically deformable, an 
engagement hole 26Rb which is formed in the support plate 26Ra and an 
engagement projection 62Rc which is formed at the lower part of the casing 
62R of the first rotational mechanism 60R. Therefore, when the first 
rotational resistance mechanism 60R is inserted into the first storage 
space 25R, the engagement projection 62Rc elastically deforms the support 
plate 26Ra and engages with the engagement hole 26Rb. Thus, the first 
rotational resistance mechanism 60R is locked in the first storage space 
25R. The first rotational resistance mechanism 60R can be removed from the 
first storage space 25R if a free end 26Rd of the support plate 26Ra is 
lowered by a jig or other device, which disengages the engagement 
projection 62Rc of the casing 62R from the engagement hole 26Rb and then 
the first rotational resistance mechanism 60R is easily pulled out. 
A lock mechanism 26L for preventing the second rotational mechanism 60L 
from disengagement has the same construction as the lock mechanism 26R. 
The following paragraphs describe the construction of the hinge mechanism 
30 on the side of the toilet seat 40 and the toilet lid 50 with reference 
to FIG. 2. The first right hinge part 42R and the first left hinge part 
42L are formed in a neck shape at an end of the toilet seat 40. The 
distance between the inner sides of the first right hinge part 42R and the 
left hinge part 42L is designed slightly wider than the width of the 
lateral side of the main body part 22 of the attachment base 20. A 
round-ended elongate hole 42Ra is formed to penetrate the first right 
hinge part 42R. A round hole 42Lb with a round section is formed to 
penetrate the first left hinge part 42L. The round-ended elongate hole 
42Ra is so formed that the longitudinal length is the same as the diameter 
of the round hole 42Lb but the width is smaller than the diameter. 
The second right hinge part 52R and the second left hinge part 52L at 
opposite sides of the toilet lid 50 are so formed respectively as to be 
positioned on the outer side of the first right hinge part 42R and the 
first left hinge part 42L. The second right hinge part 52R comprises a 
round hole 52Rb and the second left hinge part 52L comprises a round-ended 
elongate hole 52La. The round hole 52Rb and the round-ended elongate hole 
52La are so formed as to be positioned line-symmetrical with the 
round-ended elongate hole 42Ra of the first right hinge part 42R and the 
round hole 42Lb of the first left hinge part 42L. 
The hinge mechanism 30 includes the first and second support pins 36R and 
36L which have the same configuration. The first and second support pins 
36R and 36L are integrally formed in a bar shape incorporating a head part 
36a, an engagement part 36b and a tip part 36c which is almost of a cone 
shape. The shape of the engagement part 36b, which has a flat and thin 
section, is a cylinder with both lateral sides cut away parallel for a 
prescribed width. The engagement part 36b of the first support pin 36R is 
so shaped as to rotate freely through the round hole 52Rb of the second 
right hinge part 52R but as to fit the round-ended elongate hole 42Ra of 
the first right hinge part 42R. On the other hand, the engagement part 36b 
of the second support pin 36L is so shaped as to fit the round-ended 
elongate hole 52La of the second left hinge part 52L but as to rotate 
freely through the round hole 42Lb of the first left hinge part 42L. 
The cap 38R comprises a disk part 38b which has an engagement projection 
38a on its inner surface and an arc part 38c. The engagement projection 
38a of the disk part 38b is so shaped as to engage with a pin recess 36d 
of the first support pin 36R. The cap 38R is mounted on a cap attachment 
part 54R when it is pressed into the cap attachment part 54R on the 
lateral side of the second right hinge part 52R and then securely fastened 
when the engagement projection 38a engages with a pin recess 36d of the 
first support pin 36R. The cap 38L is mounted on a cap attachment part 54L 
of the second left hinge part 52L in the same way. 
FIG. 8 is a sectional view of the second rotational resistance mechanism 
60L along its axial shaft line. The second rotational resistance mechanism 
60L is a mechanism which applies rotational resistant force to the second 
support pin 36L in one direction by wrenching resistance of a spring. The 
second rotational resistance mechanism 60L comprises a casing 62L, a shaft 
63L, a spring 64, a slider 65, a cam 66, a washer 68 which is secured to 
the shaft 63L by a tapped tight fit 67, and an O ring 69 which is 
positioned between the outer round surface of the shaft 63L and the inner 
round surface of the casing 62L. The casing 62L comprises, as described 
above, the cylinder main body part 62La and the rotation stopper 62Lb, and 
also a cap 62Ld to enclose the end part. 
FIG. 9 is a lateral perspective view to show the shaft 63L, the slider 65 
and the cam 66. The shaft 63L comprises a large-diameter part 63a and an 
engagement part 63c. The large-diameter part 63a, which has a round 
section, comprises a ring part 63e which is fitted to rotate inside and is 
supported by an opening 62Le of the casing 62L at an end part and a 
fitting hole 63Ld which fits the engagement part 36b of the second support 
pin 36L in the shaft core. The shape of the engagement part 63c which has 
a narrow rectangular section is a cylinder with two lateral sides cut away 
parallel for a prescribed width. 
The slider 65 comprises a ring part 65a, a fitting hole 65b which has a 
narrow rectangular section and is formed in the ring part 65a and fitted 
on the engagement part 63c of the shaft 63L, an engagement part 65d which 
supports the spring 64 and two hill-shaped tapered parts 65e which contact 
the cam 66 tangentially. 
The cam 66 comprises a main body part 66a, two cam surfaces 66b and 66c 
which are formed at one end surface of the main body part 66a and which 
respectively contact the tapered parts 65e of the slider 65 tangentially 
and six projections 66d which are formed at the other end of the main body 
66a and secured at the end of the casing 62L (FIG. 8). The spring 64 is 
positioned on the outer round surface of the shaft 63L and a first end of 
the spring 64 is locked to the engagement part 65d which is formed on the 
end surface of the slider 65. The other end of the spring 64 is attached 
to casing 62L. 
The following paragraphs describe the actions of the second rotation 
resistance mechanism 60L. When the shaft 63L of the second rotational 
resistance mechanism 60L is rotated in the counter-clockwise direction r1 
(FIG. 6), the slider 65 rotates with the shaft 63L as a unified body when 
the slider 65 rotates beyond a prescribed angle, as the slope part 65e 
rides over the cam surfaces 66b and 66c of the cam 66, the slider 65 
slides in the direction of the arrow "d" while rotating. Since the spring 
64 is wrenched while being compressed, the shaft 63L receives rotational 
resistant force as a reaction force. On the other hand, since the spring 
64 unwinds when the slider 65 rotates along with the clockwise rotation of 
the shaft 63L, the shaft 63L receives no rotational resistant force. 
Therefore, the second rotational resistance mechanism 60L gives rotational 
resistant force at a rotation beyond the prescribed angle in the 
counter-clockwise direction r1 but gives no resistant force at a rotation 
in the clockwise direction. 
The first rotational resistance mechanism 60R has a construction similar to 
the second rotational resistance mechanism 60L except that it is 
constructed to give rotational resistant force with a rotation in 
clockwise direction r2 of the shaft 63R (FIG. 5). To fit the weight of the 
toilet seat 40 which is different from that of the toilet lid 50, the 
spring 64 of the first rotational resistance mechanism 60R has a different 
spring constant from that of the second rotational resistance mechanism 
60L. 
The following paragraphs describe assembling operations of the toilet seat 
40 and the toilet lid 50 to the attachment base 20 where the hinge 
mechanism 30 is utilized. As in the FIGS. 4 through 7, the first and 
second rotational resistance mechanisms 60R and 60L are assembled while 
being inserted into the first and second storage spaces 25R and 25L of the 
attachment base 20. Then, as in FIG. 2, while the first right hinge part 
42R and the first left hinge part 42L are positioned to the lateral side 
of the attachment base 20, the second right hinge part 52R and the second 
left hinge part 52L are positioned on their outer side. 
Since the springs 64 of the first and second rotational resistance 
mechanisms 60R and 60L are not wound when they are attached to the 
attachment base 20, the fitting holes 63Rd and 63Ld of the shafts 63R and 
63L are tilted by about 30 degrees from the center line CL (FIG. 6). While 
the toilet seat 40 and the toilet lid 50 are inclined to this angle, the 
round-ended elongate hole 42Ra of the toilet seat 40 and the round-ended 
elongate hole 52La of the toilet lid 50 are aligned with the fitting holes 
63Rd and 63Ld of the shafts 63R and 63L. 
Next, the first support pin 36R is inserted into the round hole 52Rb of the 
second right hinge part 52R, the round-ended elongate hole 42Ra of the 
first right hinge part 42R and then into the fitting hole 63Rd of the 
first rotational resistance mechanism 60R (FIG. 10). The second support 
pin 36L is inserted into the round-ended elongate hole 52La of the second 
left hinge part 52L, the round hole 42Lb of the first left hinge part 42L 
and then into the fitting hole 63Ld of the second rotational resistance 
mechanism 60L. 
Next, the caps 38R and 38L are respectively attached to the attachment 
parts 54R and 54L of the second right hinge part 52R and the second left 
hinge part 52L. FIGS. 11 and 12 show the operation of attaching the caps 
38R. This completes the assembling operations of the toilet seat 40 and 
the toilet lid 50. In this state, the rotational force from the toilet 
seat 40 is transmitted to the first rotational resistance mechanism 60R 
via the elongated-circle hole 42Ra of the first right hinge part 42R and 
the first support pin 36R. The rotational force from the toilet lid 50 is 
transmitted to the second rotational resistance 60L via the round-ended 
elongate hole 52La of the second left hinge part 52L and the second 
support pin 36L. Therefore, if the toilet lid 50 and the toilet seat 40 
are lowered with the hinge mechanism 30 immediately after attaching the 
toilet seat 40 and the toilet lid 50 to the attachment base 20, the 
springs 64 in the first and second rotational resistance mechanisms 60R 
and 60L become twisted. 
The following paragraphs describe the raising and lowering operations of 
the toilet seat 40 and the toilet lid 50 with utilization of the hinge 
mechanism 30. FIG. 13 is a sectional drawing along the line L--L in FIG. 1 
and FIG. 14 is a sectional drawing showing the state where the toilet lid 
50 in FIG. 13 is raised. When upward force is applied to the toilet lid 50 
when the toilet seat 40 and the toilet lid 50 are fully lowered, the 
second support pin 36L rotates with the shaft 63L as a unified body. The 
rotational force from the shaft 63L is applied via the slider 65 to the 
twisted spring 64 in the unwinding direction and thus the spring 64 is 
unwound. The unwinding force of the spring 64 at this time will not give 
significant resistance when the toilet lid 50 is raised. 
On the other hand, when the toilet lid 50 is lowered from the upright 
position, the rotational force from the shaft 63L will not be transmitted 
to the spring 64 since the slider 65 does not contact the cam 66 until the 
toilet lid 50 reaches a prescribed angle (for example, 30 degrees). 
Therefore, the toilet lid 50 rotates rapidly without resistance until the 
prescribed angle is reached. When the toilet lid 50 is lowered beyond the 
prescribed angle (30 degrees), the spring 64 is twisted while being 
compressed since the rotational force from the shaft 63L rotates the 
slider 65 while moving it in the direction of the arrow d. Such twisting 
force applied to the spring 64 acts as rotational resistant force against 
the second support pin 36L and eventually against the toilet lid 50. 
Therefore, the toilet lid 50 will rotate smoothly to open without receiving 
resistant force and the toilet lid 50 will be lowered to close slowly when 
it is released. In the same way, when the toilet seat 40 is raised or 
lowered, the toilet seat 40 receives rotational resistant force from the 
first rotational resistance mechanism 60R in the downward direction to 
close slowly. 
The embodiment described above produces the following effects. If the 
toilet seat 40 and the toilet lid 50 are different in their weight, the 
rotational resistant force generated by the spring 64 in the first 
rotational resistance mechanism 60R needs to be set different from that of 
the spring 64 in the second rotational resistance mechanism 60L. The 
casings 62R and 62L for the first and second rotational resistance 
mechanisms 60R and 60L are different from each other in their external 
configurations and also the first and second storage spaces 25R and 25L 
where they are positioned and secured. Therefore, the first rotational 
resistance mechanism 60R cannot be attached to the second storage space 
25L and the second rotational resistance mechanism 60L cannot be attached 
to the first storage space 25R by mistake. 
Moreover, since the configuration of the rotation stoppers 62Rb and 62Lb of 
the casings 62R and 62L are modified as a means of making the first and 
second rotational resistance mechanisms 60R and 60L different in the 
external configuration, applications require no more modifications in the 
mechanisms of the other parts. 
FIGS. 15 through 18 show an alternative embodiment. FIG. 15 is a 
perspective drawing showing a first rotational resistance mechanism 160R 
and a second rotational resistance mechanism 160L, and FIG. 16 is a 
sectional drawing of an attachment base 120; FIG. 17 is a drawing of a 
view in direction B in FIG. 16 and FIG. 18 is a drawing of a view in 
direction A in FIG. 16. The first rotational resistance mechanism 160R has 
almost the same constitution as the first rotational resistance mechanism 
60R except that the configuration of a casing 162R is different. On the 
bottom of the casing 162R, a raised rotation stopper part 162Rb is formed. 
The upper surface of the raised rotation stopper part 162Rb is triangular. 
The second rotational resistance mechanism 160L also has the same 
constitution as the second rotational resistance mechanism 60L except for 
a casing 162L. A rotation stopper part 162Lb is formed on the bottom of 
the casing 162L. The upper surface of the rotation stopper part 162Lb is 
square. On the other hand, the attachment base 120 comprises a first 
storage space 125R and a second storage space 125L. A positioning recess 
125Ra and a positioning recess 125La are formed respectively on the 
bottoms of the first storage space 125R and the second storage space 125L. 
The positioning recess 125Ra which is to fit the raised rotation stopper 
part 162Rb of the first rotational resistance mechanism 160R is 
triangular, and the positioning recess 125La which is to fit the rotation 
stopper part 162Lb of the second rotational resistance mechanism 160L is 
square. 
Therefore, the first and second rotational resistance mechanisms 160R and 
160L are respectively attached to the first and second storage spaces 125R 
and 125L and incorrect assembly is prevented. 
FIG. 19 is a perspective drawing to show a hinge mechanism 230 in the state 
prior to assembly. The hinge mechanism 230 comprises an attachment base 
220, a first hinge unit 230R which supports a toilet seat 240 and a second 
hinge unit 230L which supports a toilet lid 250. The first hinge unit 230R 
and the second hinge unit 230L are located respectively in a lower 
position and a higher position of the attachment base 220. 
The attachment base 220 comprises support parts 220R and 220L which are 
situated on the upper part of a western-style toilet bowl so as to face 
each other. The support part 220R comprises a securing pin 237R on its 
inner lower part and a fitting hole 222R in its inner upper part. The 
support part 220L comprises a securing pin 237L on its inner upper part 
and a fitting hole 222L in its inner lower part. 
The first hinge unit 230R comprises a first storage space 232R which is 
formed at the end part of the toilet seat 240 and a first rotational 
resistance mechanism 260R which is stored in the first storage space 232R. 
The first rotational resistance mechanism 260R comprises a shaft 263R 
which fits and supports the securing pin 237R and a shaft body 262Rc which 
projects from the end part of a casing 262R and which is supported by a 
fitting hole 222L in the support part 220L. 
The second hinge unit 230L has a construction similar to the first hinge 
unit 230R, which comprises a second storage space 232L on the side of the 
toilet lid 250 and a second rotational resistance mechanism 260L. The 
configurations of the second storage space 232L and the second rotational 
resistance mechanism 260L differ from those of the first storage space 
232R and the first rotational resistance mechanism 260R to prevent 
incorrect attachment. The second rotational resistance mechanism 260L is 
interlocked with the securing pin 237L and supported by the fitting the 
shaft body 262Lc into the hole 222R. 
In this construction, the toilet seat 240 and the toilet lid 250 receive 
rotational resistant force from the first and second rotational mechanisms 
260R and 260L in the downward direction. 
The present invention is not limited to the embodiments described above but 
available in various modes within the scope of the invention.