JPH1129164A - Hinge cap made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable easy detachment, by forming a small-diameter part in an area other than one peripheral area where a hinge is formed, and by making the length of the skirt of an upper cap corresponding to the small-diameter part longer in its axial direction, thereby making it possible to move the lower end of the small-diameter part, which is opposite a hinge, forcibly in the axial direction. SOLUTION: A small-diameter part 40 whose outside diameter is smaller than that of one peripheral area C1 only by a specific width in a radial direction is formed in other peripheral area C1 of an outside mounting wall other than the one peripheral area C1 where a hinge 5 is formed. Also, in the length of the skirt of an upper cap 6 in its axial direction, a part 32a corresponding to the other peripheral area C2 is formed longer than a part corresponding to the one peripheral area C1 so as to cover the peripheral face of the small- diameter part 40 when the upper cap 6 is closed. When the cap 2 is separately recovered, the upper cap 6 is rotated in relation to a main body 4 to be unlocked. Then, a flange 42 is forcibly moved with fingertips in the axial direction where it is separated from a container opening. This makes it easy to detach the cap 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin made of a synthetic resin which is used by being plugged into an opening of a container containing contents such as a liquid, and which can be easily separated from the opening of the container at the time of sorting and collecting. It relates to a hinge cap.

[0002]

2. Description of the Related Art An opening of a container containing contents such as a liquid is sealed with a cap made of, for example, a synthetic resin to prevent the contents from leaking. The synthetic resin cap is generally attached by being plugged into the container opening. When using a container with contents, the cap must be securely attached to the container opening while maintaining a sufficiently tight seal and must not be easily removed.
On the other hand, after the contents are consumed, the cap is required to be easily detached from the container opening in order to separate and collect the contents to reuse resources and protect the environment.

As a synthetic resin cap for satisfying the above-mentioned requirements, for example, a cap disclosed in Japanese Utility Model Laid-Open No. 6-59247 can be mentioned. The synthetic resin cap disclosed in the above publication includes a main body (a spout) and an upper lid (an overcap). The main body includes a discharge guide wall (beak) erected on a top wall (top plate), a scheduled opening part (opening part) opened by a break part, and a container opening part erected downward on the periphery of the top wall. And an outer cylinder having a threaded portion protruding above the outer mounting wall. The upper lid has a length that covers the outer cylinder and the outer mounting wall, and has a side wall provided with a screw portion that can be screwed to a screw portion of the outer cylinder. The upper lid is connected to the side wall via a hinge to be openable and closable. Lid. The outer mounting wall of the main body is formed in a divergent shape. Alternatively, a plurality of cuts (cuts) are formed in the outer mounting wall. When the upper lid is screwed into the main body, the side wall presses the outer mounting wall, and the main body is mounted on the container opening.

[0004]

The above-mentioned conventional synthetic resin cap is a so-called synthetic resin hinge cap,
This synthetic resin hinge cap is configured such that when the upper lid is screwed into the main body, the side wall presses the outer mounting wall, the diameter of the outer mounting wall is reduced, and the main body is mounted on the container opening. An excellent effect is obtained that it is firmly attached to the container opening and does not come off easily. However, after the consumption of the contents, in order to separate the cap from the container opening for separation and collection,
Prior to detaching the main body from the container opening, the upper lid must be relatively rotated at the screwing portion with respect to the main body attached to the container opening and removed from the main body, and the removal operation is relatively troublesome, and the side wall is There is a possibility that the rotation operation of the upper lid with respect to the main body becomes difficult due to the pressing of the outer mounting wall. In other words, when sorting and collecting,
There is a possibility that the cap cannot be easily detached from the container opening.

Although the above-mentioned conventional hinge cap made of synthetic resin is essentially composed of a single part integrally molded, the main body and the upper lid are integrally screwed together as described above. Since it is composed of separate members such as
Although it is a hinge cap made of synthetic resin, it is composed of two parts. As a result, the conventional synthetic resin hinge cap increases the number of parts and cannot be integrally formed by the conventional molding method, so that the manufacturing cost increases.

The present invention has been made on the basis of the above-mentioned facts. The main object of the present invention is to provide a container in which contents are present, and to use the container sufficiently securely in the container opening so that the container does not come off easily. On the other hand, an object of the present invention is to provide a novel synthetic resin hinge cap which can be easily detached from the container opening at the time of sorting and collecting and can be manufactured at a relatively low cost.

[0007]

According to the present invention, in order to achieve the above-mentioned main object, a main body and an upper lid integrally formed on the main body via a hinge so as to be openable and closable are provided. A top wall, an annular outer mounting wall extending downward from a periphery of the top wall, an opening portion to be formed on the top wall, an annular discharge guide wall of the top wall extending upward from around the opening portion, and A locking ridge formed on the outer peripheral surface of an annular locking wall extending upward from the outside of the discharge guide wall;
A top wall portion, a skirt portion extending downward from a periphery of the top wall portion,
A locking ridge formed on an inner peripheral surface of the skirt portion and locked by the locking ridge of the main body; a container opening is formed on an inner peripheral surface of the outer mounting wall of the main body. A part of the outer mounting wall of the main body, in which the hinge is formed, in a synthetic resin hinge cap having a locking projection formed on a locking jaw formed on an outer peripheral surface. A small-diameter portion whose outer diameter is smaller than the outer diameter of the partial peripheral region by a predetermined radial width is formed in the other peripheral region except the peripheral region, and the axial length of the skirt portion of the upper lid is When the upper lid is closed, a portion corresponding to the other peripheral region is defined to be longer than a portion corresponding to the partial peripheral region so that the outer peripheral surface of the small-diameter portion of the outer mounting wall can be covered. A hinge cap made of synthetic resin,
Is provided.

The synthetic resin hinge cap of the present invention is attached by being plugged into the opening of the container in which the contents are stored with the upper lid closed with respect to the main body. At the time of tapping, the outer diameter of the outer mounting wall, especially the outer diameter of the small diameter portion, is instantaneously enlarged, but excessive expansion is prevented by being restrained by the skirt portion of the upper lid covering the outer peripheral surface, and Since it is returned to the diameter, there is no possibility of breakage (when the cut formed in the outer mounting wall is a score).

After the tapping, the outer peripheral surface of the small diameter portion of the outer mounting wall is covered with the skirt portion of the upper lid in a state where the upper lid is closed. The retaining force of the locking ridge on the locking jaw of the container opening is sufficiently maintained. As a result, the hinge cap is firmly attached to the container opening, maintains the sealing performance, and does not easily come off.

On the other hand, at the time of sorting and collecting, the upper lid is opened with respect to the main body, and the skirt portion of the upper lid is opened from a position covering the outer peripheral surface of the small diameter portion of the outer mounting wall. In particular, by forcibly moving the lower end of the portion radially opposed to the hinge portion with the fingertip in the axial direction away from the container opening, the outer mounting wall can be easily detached from the container opening. Therefore, the entire hinge cap is easily detached from the container opening.

The synthetic resin hinge cap of the present invention comprises one part in which the main body and the upper lid are connected via a hinge, and can be integrally formed by a conventional molding method (injection molding). Therefore, it can be manufactured at a relatively low cost.

Further, the locked ridge of the main body is locked by moving over the locking ridge of the main body in the axial direction so that the locking ridge of the main body is closed when the upper lid is closed with respect to the main body. Even if the liquid such as soy sauce attached to the periphery tries to scatter outside due to the pressure at the time of the above-mentioned locking (so-called liquid splash may occur), it corresponds to the above-mentioned other peripheral area of the peripheral portion of the top wall of the main body. Since the portion is covered by a relatively long skirt portion of the upper lid in the axial direction, liquid splash is reliably prevented.

In the present invention, the upper lid is closed, and the locking jaw is plugged into the container opening manufactured to have an outer diameter dimension having a maximum allowable plus tolerance, Even if the outer diameter of the outer peripheral surface of the small-diameter portion of the outer mounting wall is substantially maximized, the outer diameter of the outer peripheral surface of the small-diameter portion is changed to the inner circumference of the skirt. Preferably, a gap is provided in advance between the inner peripheral surface of the skirt portion and the outer peripheral surface of the small diameter portion so as not to substantially exceed the inner diameter of the surface.

According to the hinge cap made of synthetic resin of the present invention, even when the outer diameter of the locking jaw is plugged into the container opening manufactured to the maximum allowable size, the small-diameter portion of the outer mounting wall can be used. The outer peripheral surface of the skirt presses the inner peripheral surface of the skirt radially outward, thereby reliably preventing the resistance of the upper lid from opening and closing, so that the opening and closing of the upper lid with respect to the main body is always smooth as desired. Will be performed.

In the present invention, the clearance between the inner peripheral surface of the skirt portion and the outer peripheral surface of the small diameter portion is S, and the tolerance of the outer diameter of the locking jaw of the container opening is Z. Then, it is preferable that the relationship between S and Z is defined as S ≧ 1 / 2Z.

According to the hinge cap made of synthetic resin of the present invention, the above-mentioned effects are more specifically achieved. However, it is assumed that the small-diameter portion of the outer mounting wall of the main body and the skirt portion of the upper lid are manufactured to predetermined dimensions without error.

In the present invention, the lower end of the small diameter portion is
At least a portion radially opposed to the hinge portion,
A flange portion projecting outward in the radial direction is formed,
Is preferred.

In the synthetic resin hinge cap according to the present invention, as described above, when the lower end of the outer mounting wall is forcibly moved by the fingertip in the axial direction away from the container opening at the time of sorting and collecting, the flange is caught by the fingertip. It can be used as a part, and detachment from the container opening can be made easier. The present invention is particularly useful when an overhang ring (transfer ring) is formed at the container opening.

In the present invention, it is preferable that cuts extending from the lower end to the upper half of the outer mounting wall are formed at intervals in the circumferential direction.

In the synthetic resin hinge cap according to the present invention, the outer mounting wall can be more easily separated from the container opening at the time of sorting and collecting. Therefore, detachment of the entire hinge cap from the container opening can be more easily performed.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a synthetic resin hinge cap constructed in accordance with the present invention will be described below in more detail with reference to the accompanying drawings. The synthetic resin hinge cap, generally designated by the numeral 2, comprises a main body 4 and an upper lid 6 integrally formed on the main body 4 via a hinge 5 so as to be openable and closable. The main body 4 and the upper lid 6 can be integrally molded from a suitable synthetic resin such as polypropylene or polyethylene. The body 4 has a top wall 8 that extends substantially horizontally. A breakable score 10 is formed on the top wall 8. As shown in FIG. 5, the score 10 is formed in a loop shape having an appropriate shape when viewed from the axial direction, and forms the scheduled opening portion 12. An opening pull ring 14 extending upward is formed in the opening portion 12. The top wall 8 further includes an annular discharge guide wall 16 extending upward from the periphery of the scheduled opening portion 12, an annular locking wall 18 extending upward from the periphery of the discharge guide wall 16, and extending downward from the periphery of the top wall 8. In the annular outer mounting wall 20 and the top wall 8, an annular inner mounting wall 22 extending downward from the inside of the outer mounting wall 20 is formed. A locking ridge 24 is formed on the outer peripheral surface of the annular locking wall 18. An annular gap is formed between the outer mounting wall 20 and the inner mounting wall 22.

The upper lid 6 is provided on the top wall 3 extending substantially horizontally.
0 is provided. The top wall portion 30 is formed with a skirt portion 32 extending downward from the periphery thereof, and a cylindrical seal wall 34 extending downward from inside the skirt portion 32. Note that “up and down” or “up and down” with respect to the upper lid 6 that opens and closes with respect to the main body 4 means the upper and lower directions when the upper lid 6 closes the main body 4 as shown in FIGS. And A locking ridge 36 is formed on the inner peripheral surface of the skirt portion 32. Between the lower end outer edge of the partial peripheral area C1 (see FIG. 1) of the skirt portion 32 of the upper lid 6 and the corresponding upper end outer edge of the peripheral edge of the top wall 8 of the main body 4 in the corresponding partial peripheral area C1. The hinge part 5 is interposed.

An engaging projection 37 is formed on the inner peripheral surface of the outer mounting wall 20 of the main body 4 over the entire periphery. The outer mounting wall 20 is provided with a plurality of cuts 38 extending from the lower end thereof to the upper half including the locking projections 37 at intervals in the circumferential direction. The cut 38 comprises a slit completely broken in the radial direction in this embodiment, but may be a score partially broken in the radial direction. Further, since the outer mounting wall 20 is thinner than a normal cap, even in an embodiment in which a slit or a score is not formed, it is easier to remove after use (at the time of sorting and collecting) than a conventional cap. Needless to say, there is. Further, instead of forming slits or scores, there may be an embodiment in which one or a plurality of thin portions extending relatively widely in the circumferential direction are formed at intervals in the circumferential direction.

The outer mounting wall 20 of the main body 4 has a peripheral region C2 (partial peripheral region other than the peripheral region C1) other than the peripheral region C1 (partial region in the circumferential direction) where the hinge portion 5 is formed. In the other remaining region), a small-diameter portion 40 having an outer diameter smaller than the outer diameter of the part of the peripheral region C1 by a predetermined radial width is formed. At the lower end of the small-diameter portion 40, a flange portion 42 that projects substantially horizontally outward in the radial direction is formed. Flange part 42
Are defined to be the same as the outer diameter of the partial peripheral area C1 of the outer mounting wall 20, and are mutually continuous. The upper surface 42a of the flange portion 42 extends inclining upward in the axial direction at both ends in the circumferential direction of the flange portion 42, and is continuous with the annular upper surface 8a of the peripheral edge of the top wall 8. Top wall 8
Are positioned on the same plane orthogonal to the axis.

The skirt portion 32 of the upper lid 6 has an annular lower surface 6a.
have. The lower surface 6a of the upper lid 6 is positioned on the same plane orthogonal to the axis. Skirt part 3 of upper lid 6
2 is formed so that a portion 32a corresponding to the other peripheral area C2 hangs further downward in the axial direction from the lower surface 6a. That is, the axial length of the skirt portion 32 of the upper lid 6 is
When the upper lid 6 is closed via the hinge part 5, the outer mounting wall 2 is closed.
The portion corresponding to the other peripheral region C2 is defined to be longer than the portion corresponding to the partial peripheral region C1 so that the outer peripheral surface of the small-diameter portion 40 can be covered. As shown in FIGS. 3 and 4,
The upper lid 6 is attached to the main body 4 by locking the locked ridge 36 of the skirt portion 32 with the locking ridge 24 of the main body 4, and the upper part of the main body 4 is closed. With the upper lid 6 closed, the lower surface 6a of the skirt portion 32 is positioned substantially in contact with the annular upper surface 8a of the main body 4, and the lower end surface of a portion 32a of the skirt portion 32 corresponding to another peripheral area C2. 32b is positioned so as to face the upper surface 42a of the flange portion 42 with a slight gap or substantially in contact. With the upper lid 6 closed as described above, the outer peripheral surface of the skirt portion 32a covering the outer peripheral surface of the small-diameter portion 40 of the outer mounting wall 20 is partially peripheral area C1 of the outer mounting wall 20.
Are positioned on substantially the same circumferential surface as the outer circumferential surface of the. A tab 33 for opening the upper lid 6 is formed at a lower end of a peripheral region of the skirt portion 32a that faces the hinge portion 5 in the radial direction.

As shown in FIG. 4, a container 50 made of a suitable synthetic resin such as polyethylene terephthalate, glass, or the like has a container opening 52.
A locking jaw 54 is formed on the outer peripheral surface of the container opening 52. An extension ring (transfer ring) 56 is formed on the outer peripheral surface of the container opening 52 below the locking jaw 54. The hinge cap 2 is attached by plugging the container opening 52 after the contents such as a liquid are stored in the container 50. By the stopper of the hinge cap 2, the outer peripheral surface of the inner mounting wall 22 is pressed into the inner peripheral surface of the container opening 52, and the locking projection 37 of the outer mounting wall 20 is formed on the outer peripheral surface of the container opening 52. It is positioned at a position beyond the locking jaw 54.

When the locking projection 37 of the outer mounting wall 20 gets over the locking jaw 54 of the container opening 52, the outer mounting wall 2
Although the outer diameter of 0, especially the outer diameter of the small diameter portion 40 is instantaneously enlarged,
It is restrained by the skirt portion 32, particularly the skirt portion 32a, of the upper cover 6 covering the outer peripheral surface, and excessive expansion is prevented, and the outer diameter is immediately returned to the original outer diameter. (If the cut 38 formed is a score).

After the cap 2 is closed, the outer peripheral surface of the small diameter portion 40 of the outer mounting wall 20 is covered by the skirt portion 32a of the upper lid 6 in a state where the upper lid 6 is closed.
0 is restrained from expanding outward in the radial direction, and the locking projection 3
7, the holding force of the container opening 52 to the locking jaw 54 is sufficiently maintained.

At the time of sorting and collecting the hinge cap 2, the upper cover 6 is rotated around the hinge portion 5 with respect to the main body 4, and the upper cover 6 is rotated.
Is released by releasing the locking of the locked ridges 36 with the locking ridges 24 of the main body 4 so that the skirt portion 32a of the upper lid 6 covers the outer peripheral surface of the small diameter portion 40 of the outer mounting wall 20. Let it open. Next, the lower end of the small-diameter portion 40 of the outer mounting wall 20 of the main body 4, in particular, the lower end of the portion radially opposed to the hinge portion 5, that is, the flange portion 42 is moved in the axial direction away from the container opening 52 by a fingertip (upward in FIG. ), The outer mounting wall 2
0, and thus the hinge cap 2 is easily detached from the container opening 52. The flange portion 42 can be used as a hook portion for a fingertip, and can be easily detached from the container opening portion 52. This configuration is particularly useful when an overhang ring 56 is formed on the outer peripheral surface of the container opening 52 as shown in FIG. The flange portion 42 is provided at the lower end of the outer mounting wall 20.
The function described above can be achieved if it is formed in at least a part of the peripheral region (particularly, the peripheral region facing the hinge portion 5 in the radial direction). Of course, there may be embodiments in which the flange portion 52 is not formed. When the hinge cap 2 is removed from the container opening 52, the main body 4, that is, the hinge cap 2 can be removed via the hinge 5 by pulling the upper lid 6 instead of the flange 42.

Also, the hinge cap 2 is composed of one part in which the main body 4 and the upper lid 6 are connected via the hinge part 5, and can be integrally formed by a conventional molding method (injection molding). Can be manufactured at relatively low cost.

Further, in the hinge cap 2, the locked ridge 36 of the upper lid 6 is locked by passing over the locking ridge 24 of the main body 4 in the axial direction, so that the upper lid 6 is fixed to the main body 4. When closed, the locking ridge 2 of the main body 4
Even if the liquid such as soy sauce adhering to the periphery of the main body 4 tries to scatter outside due to the pressure at the time of the above-mentioned locking (so-called liquid spattering may occur), the other peripheral portion of the peripheral portion of the top wall 8 of the main body 4 may be used. The portion corresponding to the area C2 is covered by the skirt portion 32a having a relatively long axial length of the upper lid 6, so that the liquid splash is reliably prevented.

In the hinge cap 2, the upper cover 6
Is closed, and the locking jaw 54 is plugged into the container opening 52 manufactured to the outer diameter D having the maximum allowable plus tolerance (+ Zmax when the tolerance is Z). Even if the outer diameter of the outer peripheral surface of the small-diameter portion 40 of the mounting wall 20 is substantially maximized, the outer diameter of the outer peripheral surface of the small-diameter portion 40 is larger than the inner diameter of the inner peripheral surface of the skirt portion 32a. Skirt part 3 so as not to substantially exceed
A gap S is provided in advance between the inner peripheral surface of 2a and the outer peripheral surface of the small diameter portion 40. Therefore, the locking jaw 5
Even when the outer diameter D of 4 is plugged into the container opening 52 manufactured to the maximum allowable size, the outer peripheral surface of the small-diameter portion 40 of the outer mounting wall 20 moves the inner peripheral surface of the skirt portion 32a in the radial direction. It is surely prevented that the resistance when the upper lid 6 is opened or closed by being pushed outward is increased.

The inner peripheral surface of the skirt portion 32a and the outer mounting wall 2
The relationship between the clearance S between the outer peripheral surface of the small-diameter portion 40 and the tolerance Z of the outer diameter D of the locking jaw 54 is S ≧ １ ／.
It is preferable that Z is specified. The tolerance Z is a diameter tolerance, and the gap S is a gap on one side in the radial direction. In this configuration, it is assumed that the small-diameter portion 40 of the main body 4 and the skirt portion 32 of the upper lid 6 are manufactured with predetermined dimensions without error.

While the preferred embodiment of the apparatus for forming an annular cut surface on a synthetic resin product constructed according to the present invention has been described with reference to the accompanying drawings, the present invention is not limited to the above embodiment. In addition, various changes and modifications can be made without departing from the scope of the present invention.

[0035]

The hinge cap made of a synthetic resin according to the present invention is sufficiently securely attached to the opening of the container when the container in which the contents exist is used, and does not come off.
At the time of sorting and collecting, it can be easily detached from the container opening, and can be manufactured at a relatively low cost.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment of a synthetic resin hinge cap configured according to the present invention, showing a state where an upper lid is opened with respect to a main body.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view showing a state in which an upper lid is closed in the hinge cap shown in FIG. 2;

FIG. 4 is a cross-sectional view showing a state in which the hinge cap shown in FIG. 3 is plugged into a container opening.

FIG. 5 is a bottom view of FIG. 1 as viewed from the back.

FIG. 6 is a side view of FIG. 1 as viewed from below.

FIG. 7 is a view of FIG. 1 as viewed from the left.

[Explanation of symbols]

 2 Synthetic resin hinge cap 4 Main body 5 Hinge part 6 Top lid 8 Top wall 12 Scheduled opening part 16 Discharge guide wall 18 Annular locking wall 20 Outer mounting wall 24 Locking ridge 30 Top wall part 32, 32a Skirt part 36 Stop ridge 37 Locking protrusion 38 Cut 40 Small diameter part 42 Flange part 50 Container 52 Container opening 54 Locking jaw C1 Partial peripheral area C2 Other peripheral area S Inner peripheral surface of skirt part and outer peripheral surface of small diameter part Gap D between outer diameter of locking jaw ZD tolerance

Claims (5)

[Claims] 1. A body comprising: a main body; and an upper lid integrally formed on the main body via a hinge so as to be openable and closable, wherein the main body has a top wall, an annular outer mounting wall extending downward from a periphery of the top wall, A scheduled opening portion formed on the top wall, an annular discharge guide wall of the top wall extending upward from the periphery of the scheduled opening portion, and an outer peripheral surface of an annular locking wall extending upward from the outside of the discharge guide wall. A locking ridge formed on the top wall, a skirt portion extending downward from a periphery of the top wall portion, and a locking ridge of the main body formed on an inner peripheral surface of the skirt portion. A locking ridge locked on the ridge, the locking ridge locked on a locking jaw formed on the outer peripheral surface of the container opening on the inner peripheral surface of the outer mounting wall of the main body. A hinge cap made of a synthetic resin having a portion, wherein the hinge portion of the outer mounting wall of the main body is formed. A small-diameter portion having an outer diameter smaller than the outer diameter of the partial peripheral region by a predetermined radial width is formed in other peripheral regions except the peripheral region, and an axial length of the skirt portion of the upper lid is: When the upper lid is closed, a portion corresponding to the other peripheral region is defined to be longer than a portion corresponding to the partial peripheral region so that the outer peripheral surface of the small-diameter portion of the outer mounting wall can be covered. And a hinge cap made of synthetic resin. 2. The outer mounting with the upper lid being closed and the locking jaw being plugged into the container opening made to have an outer diameter having a maximum allowable plus tolerance. Even when the outer diameter of the outer peripheral surface of the small diameter portion of the wall is substantially maximized, the outer diameter of the outer peripheral surface of the small diameter portion is the inner diameter of the inner peripheral surface of the skirt portion. 2. The synthetic resin hinge cap according to claim 1, wherein a gap is previously provided between the inner peripheral surface of the skirt portion and the outer peripheral surface of the small diameter portion so as not to substantially exceed the size. . 3. A gap between the inner peripheral surface of the skirt portion and the outer peripheral surface of the small diameter portion is S, and a tolerance of an outer diameter dimension of the locking jaw of the container opening is Z. The synthetic resin hinge cap according to claim 2, wherein the relationship between S and Z is defined as S≥1 / 2Z. 4. A flange portion protruding radially outward is formed at least at a portion of a lower end portion of the small diameter portion facing the hinge portion in a radial direction. Item 2. The hinge cap made of synthetic resin according to item 1. 5. The synthetic resin hinge according to claim 1, wherein cuts extending from a lower end to an upper half of the outer mounting wall are formed at intervals in a circumferential direction. cap.