JP2001082445A - Hinge structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent a hinge pin from coming off while the pin is used and from obstructing the recycling of plastic containers and facilitate the insertion of the hinge pin while avoiding the damage of a plastic hinge receiving section or a hinge connection section when inserting the hinge pin. SOLUTION: In this hinge structure, the hinge pin P is prevented from coming off by inserting the hinge pin P into the plastic hinge receiving section 3 of a first member 1 and the hinge connection section 4 of a second member 2, pivotally connecting the first and second members 1 and 2 to each other, forming a large diameter section in the rear end section in the insertion direction of the hinge pin P and a locking hole 6 at either the hinge receiving section 3 or the hinge connection section 4 and locking the large diameter section into the locking hole 6. In this case, the hinge pin P is made of synthetic resin and the large diameter section is swelled over all around the periphery of a round bar-like pin body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hinge structure, and more particularly to, for example, a hinge structure for pivotally connecting a main body of a synthetic resin container and a lid with a hinge pin so as to be rotatable. This ensures that the hinge pins do not come off during use, and that the hinge pins do not hinder the recycling of the synthetic resin container. Further, when the hinge pins are inserted, the synthetic resin hinge receiving portion or the hinge connection portion is damaged. The present invention relates to a technique for facilitating insertion of a hinge pin while avoiding the problem.

[0002]

2. Description of the Related Art Conventionally, in a hinge structure, as shown in FIG. 9, a hinge pin P is inserted into a hinge receiving portion 3 of a main body 1a of a synthetic resin container and a hinge connecting portion 4 of a lid 2a, so that the main body 1a and the lid are closed. 2a is rotatably pivotally connected, a large-diameter portion 5a is formed at the rear end of the hinge pin P 'in the insertion direction, and a locking hole 6 is formed at one of the hinge receiving portion 3 and the hinge connection portion 4. The large-diameter portion 5a is engaged with the locking hole 6 to prevent removal.

[0003] The conventional hinge pin P 'uses a metal rod, and the large-diameter portion 5a is formed by bending the rear end of the hinge pin P'.

[0004]

As described above, since the conventional hinge pin P 'is formed by bending a metal rod to form the large-diameter portion 5a, the large-diameter portion 5a is formed in the circumferential direction of the hinge pin P'. As a result, the hinge pin P 'has directionality.

[0005] When the hinge pin P 'has directionality as described above, it is necessary to insert the hinge pin P' in the same direction, the insertion of the hinge pin P 'becomes troublesome, and the large diameter portion 5a is partially formed in the circumferential direction. Therefore, when the hinge pin P 'turns unexpectedly during use, there is a problem that the hinge pin P' comes out easily from the locking hole 6 and the hinge pin P 'comes off.

When the large diameter portion 5a is largely bent to make it difficult to come out of the locking hole 6, the substantial diameter of the hinge pin P 'becomes large. When the large diameter portion 5a is inserted into the hinge receiving portion 3 of the main body 1a and the hinge connecting portion 4 of the lid 2a to engage the large-diameter portion 5a into the locking hole 6, the rear portion of the locking hole 6 is provided. X is strongly pressed from the inside, so that the rear portion X of the locking hole 6
May be so-called "whitened", and this portion becomes brittle, causing breakage and cracking of the rear portion X of the locking hole 6 during use, and the hinge portion H may be broken. Was.

Further, since the hinge pin P 'is made of a metal rod, it is necessary to remove the hinge pin P' made of a metal rod when recycling a container made of synthetic resin. It requires effort.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and reliably prevents a hinge pin from coming off during use. The hinge pin does not hinder the recycling of a synthetic resin container. It is an object of the present invention to provide a hinge structure that can easily insert a hinge pin while avoiding damaging a hinge receiving portion or a hinge connection portion made of a synthetic resin when the hinge pin is inserted.

[0009]

According to the first aspect, a hinge pin P is inserted through a hinge receiving portion 3 of a first member 1 made of a synthetic resin and a hinge connection portion 4 of a second member 2 so that the first member 1 is formed.
And the second member 2 are pivotally connected to each other so that the hinge pin P
The large diameter portion 5 is formed at the rear end portion in the insertion direction, and the locking hole 6 is formed in one of the hinge receiving portion 3 and the hinge connection portion 4 so that the large diameter portion 5 is engaged with the locking hole 6. A hinge structure for retaining the hinge pin P, which is made of synthetic resin and has a large diameter portion 5.
Are bulged over the entire circumference of the round bar-shaped pin body Pa. According to such a configuration, the directionality of the hinge pin P can be eliminated and the operation of inserting the hinge pin P can be easily performed. Since the diameter portion 5 is present on the entire circumference, the hinge pin P can be reliably prevented from coming off, and the hinge pin P is made of synthetic resin. 1a, when recycling in a synthetic resin container in which the second member 2 is the lid 2a, it is possible to omit the troublesome work of removing a hinge pin made of a metal rod as in the related art, and to improve the workability in recycling. Can be enhanced.

In addition, since the hinge pin P is made of synthetic resin and the large-diameter portion 5 is formed on the entire circumference of the pin body Pa, depending on the selection of the synthetic resin material, it is inserted into the hinge receiving portion 3 or the hinge connecting portion 4 by press-fitting. Sometimes the synthetic resin pin body Pa
The large-diameter portion 5 can be contracted and deformed as compared with a metal hinge pin upon receiving a press input, and therefore, the large-diameter portion 5 is attached to the hinge receiving portion 3 or the hinge connection portion 4.
When the large-diameter portion 5 is engaged with the locking hole 6 by press-fitting, the pressing of the rear end of the locking hole 6 can be reduced. Does not "whiten" the rear end portion, and the hinge portion H does not break during use.

In the second aspect, the retaining portion 7 is formed at a distance from the large diameter portion 5 in the longitudinal direction of the hinge pin P,
It is characterized in that the retaining portion 7 is in contact with or near the edge of the hinge receiving portion 3 or the hinge connecting portion 4 in which the locking hole 6 is formed. According to such a configuration, the retaining portion 7 integrated with the hinge pin P comes into contact with the edge of the hinge receiving portion 3 or the hinge connecting portion 4 to prevent the hinge pin P from being removed. , Can be firmly achieved. Further, even if the rear end portion X of the locking hole 6 is damaged, the hinge pin P can be prevented from being removed by the retaining portion 7.

According to the third aspect, the hinge pin P is inserted through the hinge receiving portion 3 of the first member 1 made of synthetic resin and the hinge connecting portion 4 of the second member 2 so that the first member 1 and the second member 2 are connected to each other. Are pivotally connected to each other, a large diameter portion 5 is formed at the rear end of the hinge pin P in the insertion direction, and a locking hole 6 is formed at one of the hinge receiving portion 3 and the hinge connection portion 4 to form a large diameter. A hinge structure for engaging the portion 5 in the locking hole 6 to prevent the hinge 5 from being pulled out;
Is made of synthetic resin, and the large-diameter portion 5 is formed by swelling in a part of the circumference of the round bar-shaped pin body Pa in the circumferential direction. The invention is characterized in that a portion 7 is formed, and the retaining portion 7 is positioned in contact with or near an edge of the hinge receiving portion 3 or the hinge connecting portion 4 in which the locking hole 6 is formed.

According to such a configuration, since the hinge pin P is made of synthetic resin, for example, recycling is performed in a synthetic resin container in which the first member 1 is the main body 1a of the container and the second member 2 is the lid 2a. In such a case, it is possible to omit a troublesome operation of removing a hinge pin made of a metal rod as in the related art, and it is possible to enhance workability in recycling.

Further, depending on the selection of the synthetic resin material, the pin body Pa and the large-diameter portion 5 made of synthetic resin receive a press-fit when inserted into the hinge receiving portion 3 or the hinge connecting portion 4 by press-fitting. Therefore, when the large-diameter portion 5 is press-fitted into the hinge receiving portion 3 or the hinge connection portion 4 and the large-diameter portion 5 is engaged with the locking hole 6, the engagement deformation can be performed. The pressing of the rear end of the stop hole 6 can be reduced.
Does not "whiten" the rear end portion, and the hinge portion H does not break during use.

In addition, the large diameter portion 5 engaged with the locking hole 6,
The hinge pin P can be effectively prevented from being removed by the retaining portion 7 which comes into contact with the hinge receiving portion 3 or the edge of the hinge connecting portion 4, and the large diameter portion 5 is formed in the circumferential direction of the pin body Pa. Because it is partially bulged, the large diameter portion 5 and the retaining portion 7 can be easily formed integrally with the pin body Pa using a synthetic resin, which is advantageous in a mold configuration.

In the present invention, an inclined surface 8 is formed between the tip of the large diameter portion 5 and the pin body Pa, and the rear end of the large diameter portion 5 is located in the axial direction of the pin body Pa. A retaining surface 9 which is substantially vertical. According to such a configuration, the inclined surface 8 at the tip end portion
In this case, the insertion of the large diameter portion 5 can be performed lightly, and the retaining surface 9 at the rear end portion can be satisfactorily prevented from being pulled out from the locking hole 6.

[0017]

Embodiments of the present invention will be described below. 1 is an overall perspective view, FIG. 2 is a perspective view with a lid opened, and FIG. 3 is an exploded perspective view.

In this embodiment, the main body 1a of the folding container A as the first member 1 and the lid 2a of the folding container A as the second member 2 are pivotally supported on the main body 1a so that the lid 2a can be opened and closed at a hinge H. It is a concatenation. Less than,
The folding container A will be described in detail.

As shown in FIGS. 1 and 2, the folding container A includes a rectangular bottom plate 10, a rectangular frame-shaped upper frame 11 disposed above the bottom plate 10, and a space between the bottom plate 10 and the upper frame 11. Side plates 12 disposed on both sides of the bottom plate 10 and end plates 13 disposed at both ends between the bottom plate 10 and the upper frame 11. The upper end of the end plate 13 is rotatably connected to the upper frame 11. End plate 1
3 can be turned upside down, and the side plate 12 can be
And the lower side plate 15 of the lower half, the upper end of the upper side plate 14 is rotatably connected to the upper frame 11 and the lower side plate 15
Is rotatably connected to the bottom plate 10, and the lower end of the upper side plate 14 and the upper end of the lower side plate 15 are connected via a connecting portion 16.

A through hole 17 is formed in the lid 2a, and the main body 1a
A protrusion 18 is formed in the cover 2, and the closed state of the lid 2 a is maintained by inserting the through hole 17 into the protrusion 18. The edge of the lid 2a is formed in a wavy shape.

The structure of the folding container A can be variously changed in design, and it goes without saying that the present invention can be implemented in addition to the folding container A.

FIGS. 4 and 5A show the structure of the hinge portion H. A tunnel-like portion 19 and a receiving piece 20 having a T-shaped cross section are formed at the upper edge of the long side of the main body 1a. The hinge receiving portions 3 are formed at appropriate intervals in the longitudinal direction of the upper edge portion. A hole 21 is formed in the tunnel portion 19 so that the hinge pin P to be inserted can be seen. The holes 21 of the tunnel-like portion 19 at both ends on the long side are the locking holes 6
Becomes FIGS. 4B to 4E show B in FIG.
-B line sectional view, CC line sectional view, DD line sectional view, E-
FIG. 4 shows a cross-sectional view taken along line E. On the long side of the lid 2a, a hinge connection portion 4 having a plurality of arc-shaped portions 22 so that the hinge pin P can be seen is formed. The hinge pin P is inserted through the hinge receiving portion 3 and the hinge connecting portion 4 to cover the main body 1a with the lid 2a.
Are pivotally connected to each other.

The hinge pin P in the present invention is made of synthetic resin, for example, PP (polypropylene).
Glass fiber or nylon + glass fiber may be used, and any material may be used as long as it contracts when subjected to a pressing force.

As shown in FIG. 6, a large diameter portion 5 is formed at the rear end of the hinge pin P in the insertion direction on the entire circumference. Large diameter part 5
Is engaged with the locking hole 6 to prevent the hinge pin P from being pulled out.

As described above, the locking hole 6 is formed in the hinge receiving portion 3 and the large-diameter portion 5 is engaged with the locking hole 6 to prevent removal. Since the large-diameter portion 5 protrudes over the entire circumference of the round bar-shaped pin body Pa, the directionality of the hinge pin P can be eliminated, and the operation of inserting the hinge pin P can be facilitated. Moreover, since the hinge pin P is made of synthetic resin, when recycling in the folding container A made of synthetic resin, it is possible to omit the troublesome work of removing the hinge pin P 'made of a metal rod as in the related art. It is possible to improve the workability in recycling.

More specifically, since the hinge pin P is made of synthetic resin and the large-diameter portion 5 swells around the entire circumference of the pin body Pa, the synthetic resin pin is inserted when the hinge pin P is pressed into the hinge receiving portion 3. The main body Pa and the large-diameter portion 5 can be contracted and deformed by receiving a press input as compared with the metal hinge pin Pa.
Alternatively, when the large-diameter portion 5 is press-fitted into the hinge connection portion 4 and the large-diameter portion 5 is engaged with the locking hole 6, it is possible to reduce strong pressing of the rear end portion X of the locking hole 6. Therefore, the rear end portion X of the locking hole 6 does not "whiten", and the hinge portion does not break during use.

The large-diameter portion 5 of the hinge pin P has a conical inclined surface 8 formed between its tip and the pin body Pa, and the rear end of the large-diameter portion 5 has an axis of the pin body Pa. A retaining surface 9 that is substantially perpendicular to the center direction is formed. According to such a configuration, the large-diameter portion 5 can be lightly inserted into the inclined surface 8 at the front end portion, and can be satisfactorily prevented from being pulled out of the locking hole 6 at the rear end retaining surface 9. It is.

Further, in the hinge pin P, the large diameter portion 5
A ring-shaped retaining portion 7 is formed at an interval in the length direction of the hinge pin P. A tapered surface 23 is formed at the front end of the retaining portion 7, and a locking surface 24 is formed at the rear end in a direction substantially orthogonal to the axial direction of the hinge pin P. According to such a configuration, the locking surface 24 of the retaining portion 7 is in contact with the edge of the hinge receiving portion 3 in which the retaining hole 6 is formed, thereby preventing the removal. Can be achieved more favorably.

Although not shown, in the present invention, the large-diameter portion 5 may be formed by bulging out a part of the round bar-shaped pin body Pa in the circumferential direction. The large diameter portion 5 to be inserted and the retaining portion 7 abutting on the edge of the hinge receiving portion 3 or the hinge connecting portion 4 effectively prevent the hinge pin P from being removed, while the large diameter portion 5 is connected to the pin body Pa. , The large-diameter portion 5 and the retaining portion 7 can be easily formed integrally with the pin body Pa by a synthetic resin, which may be advantageous in a mold configuration.

FIGS. 7 and 8 show another embodiment. However, the basic structure of this embodiment is the same as that of the above-described embodiment, and the common parts are denoted by the same reference numerals and the description thereof will be omitted. Omitted.

In this embodiment, as shown in FIG. 7 (a), a rib 25 is formed at a position where the hole 21 of the tunnel-like portion 19 on the side of the main body 1a is used as the locking hole 6, and the locking hole is formed. 6 is divided into a first locking hole 6a and a second locking hole 6b in the pin insertion direction. On the other hand, on the hinge pin P side, as shown in FIG. Retaining part 7
As shown in FIG. 8B, the retaining portion 7 is inserted into the second locking hole 6b, and the large diameter portion 5 is inserted into the first locking hole 6a. It was done. Further, in the present embodiment, the protrusion 2 is provided on the inner surface side portion of the rib 25.
5 a is formed and protrudes into the hole 26 side of the tunnel-shaped portion 19, and the protruding portion 25 a enters between the retaining portion 7 and the large diameter portion 5. In addition, the large diameter portion 5 and the retaining portion 7 of the present embodiment are formed all around the pin body Pa.

In the present embodiment, the retaining portion 7 does not have to pass through the tunnel-like portion 19 to the front end, but only needs to pass through the rib 25 at the intermediate portion of the tunnel-like portion 19, and includes the rear end portion X and the front end portion. This makes it easier to insert the hinge pin P as compared with a configuration that passes through all of them. Further, the protrusion 25a on the inner surface side of the rib 25 protrudes between the retaining portion 7 and the large-diameter portion 5, thereby further enhancing the retaining effect of the hinge pin P.

In the embodiment, the large diameter portion 5 is formed continuously in a columnar shape in the length direction of the hinge pin P. However, the large diameter portion 5 may be formed discontinuously, and the shape can be changed. is there.

In the embodiment, the retaining portion 7 is formed in a ring shape continuous in the circumferential direction of the hinge pin P.
It may be formed discontinuously in the circumferential direction. In this case, the large diameter portion 5 protruding partly in the circumferential direction and the retaining portion 7 may be formed in an annular shape.

[0035]

According to the first aspect, the first resin made of synthetic resin is used.
A hinge pin is inserted into a hinge receiving portion of the member and a hinge connection portion of the second member to pivotally connect the first member and the second member so as to be rotatable, and a large-diameter portion is provided at a rear end in the insertion direction of the hinge pin. And a locking hole is formed in one of the hinge receiving portion and the hinge connecting portion, and the large diameter portion is engaged with the locking hole to prevent the hinge from being removed. The hinge pin is made of synthetic resin. In addition, the large-diameter portion protrudes over the entire circumference of the round bar-shaped pin body, so that the direction of the hinge pin can be eliminated and the hinge pin can be easily inserted while the hinge pin rotates during use. Even if there is, since the large diameter portion for retaining is present on the entire circumference, the retaining of the hinge pin can be reliably performed, and since the hinge pin is made of synthetic resin, for example, One member is the body of the container,
When recycling in a synthetic resin container having the second member as a lid, it is possible to eliminate the troublesome work of removing a hinge pin made of a metal rod as in the related art, and to improve the workability in recycling. There are advantages.

Moreover, since the hinge pin is made of synthetic resin and a large diameter portion is formed on the entire circumference of the pin main body, the synthetic resin material can be selected so that the pin is inserted into the hinge receiving portion or the hinge connection portion by press-fitting. The pin body and the large-diameter portion can be contracted and deformed in comparison with a metal hinge pin upon receiving a press-in, so that the large-diameter portion is press-fitted into the hinge receiving portion or the hinge connection portion, and the large-diameter portion is pressed. When the portion is engaged with the locking hole, it is possible to reduce strong pressing of the rear end of the locking hole, and therefore, it is necessary to “whiten” the rear end of the locking hole. There is an advantage that the hinge portion is not broken during use.

According to a second aspect of the present invention, the retaining portion is formed at a distance from the large diameter portion in the length direction of the hinge pin, and the retaining portion is formed with an engaging hole. In addition to the effect of claim 1, the retaining portion integrated with the hinge pin abuts on the edge of the hinge receiving portion or the hinge connecting portion to prevent the removal. There is an advantage that the hinge pin can be more securely prevented from coming off. Further, even in the event that the rear end of the locking hole is damaged, there is an advantage that the retaining pin can prevent the hinge pin from being removed.

According to a third aspect of the present invention, a hinge pin is inserted through a hinge receiving portion of the first member made of a synthetic resin and a hinge connecting portion of the second member to pivotally pivot the first member and the second member. Connect, form a large diameter part at the rear end of the hinge pin insertion direction, form a locking hole in one of the hinge receiving part and the hinge connection part, engage the large diameter part in the locking hole and prevent it from coming off The hinge pin is made of synthetic resin, and the large diameter portion is formed by bulging a part of the circumference of the round bar-shaped pin body in the circumferential direction, and the hinge pin is spaced from the large diameter portion in the length direction of the hinge pin. Since the retaining portion is formed with a space between the hinge receiving portion and the edge of the hinge receiving portion or the hinge connecting portion in which the locking hole is formed or located near the edge of the hinge connecting portion, the hinge pin is made of synthetic resin. Therefore, for example, the first member is used as the main body of the container, and the second member is used as the second member.
When recycling in a synthetic resin container with a lid as a member, it is possible to omit the troublesome work of removing a hinge pin made of a metal rod as in the related art, and this has an advantage that workability in recycling can be improved. is there.

Further, depending on the selection of the synthetic resin material, the synthetic resin pin body and the large-diameter portion are subjected to a press input during the press-fitting into the hinge receiving portion or the hinge connection portion, so that the pin main body and the large-diameter portion are contracted and deformed as compared with the metal hinge pin. Therefore, when the large diameter portion is pressed into the hinge receiving portion or the hinge connection portion and the large diameter portion is engaged with the locking hole, the rear end portion of the locking hole is strongly pressed. Therefore, there is an advantage that the rear end of the locking hole does not "whiten" and the hinge does not break during use. .

Moreover, the large-diameter portion engaged in the locking hole and the retaining portion abutting on the edge of the hinge receiving portion or the hinge connecting portion can effectively prevent the hinge pin from being removed, and Since the large-diameter portion swells in a part of the pin body in the circumferential direction, there is an advantage in that it is advantageous in a mold configuration.

According to a fourth aspect of the present invention, an inclined surface is formed between the leading end of the large diameter portion and the pin body, and the rear end of the large diameter portion is substantially perpendicular to the axial direction of the pin body. Since the stop surface is formed, in addition to the effect of claim 1 or 3,
There is an advantage that the large diameter portion can be easily inserted on the inclined surface of the front end portion, and that the retaining hole at the rear end portion can be properly prevented from being pulled out from the locking hole.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view in which the lid is opened.

FIG. 3 is an exploded perspective view of the same.

4A is a partial plan view of the main body, FIG. 4B is a cross-sectional view taken along line BB of FIG. 4A, FIG. 4C is a cross-sectional view taken along line CC of FIG. (A) is a sectional view taken along line DD, and (e) is a sectional view taken along line EE of (a).

5A is a schematic sectional view, and FIG. 5B is a schematic sectional view in which a hinge pin is inserted.

FIG. 6A is a side view of the same hinge pin, and FIG. 6B is an enlarged side view.

7A and 7B show another embodiment of the above, wherein FIG. 7A is a partial plan view of a main body, and FIG. 7B is a side view in which a part of a hinge pin is omitted.

8A is a schematic sectional view, and FIG. 8B is a schematic sectional view in which a hinge pin is inserted.

FIG. 9 is a schematic sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st member 2 2nd member 3 Hinge receiving part 4 Hinge connection part 5 Large diameter part 6 Locking hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3E061 AA05 AB09 CA02 CA04 DB11 DB17 3E084 AA05 AA14 AA24 BA02 CA03 FA07 GA03 3J105 AA02 AA04 AB07 AB48 AC06 BA05 BA15 BA36 BB06 BB07 BB22

Claims (4)

[Claims] A hinge pin is inserted through a hinge receiving portion of a first member made of a synthetic resin and a hinge connecting portion of a second member to form a first member.
The member and the second member are rotatably pivotally connected to each other, a large-diameter portion is formed at a rear end of the hinge pin in the insertion direction, and a locking hole is formed at one of the hinge receiving portion and the hinge connection portion. A hinge structure in which the diameter portion is engaged with the locking hole to prevent the removal, and the hinge pin is made of synthetic resin and the large diameter portion is bulged over the entire circumference of the round bar-shaped pin body. And hinge structure. 2. A retaining portion is formed at a distance from the large-diameter portion in the length direction of the hinge pin, and the retaining portion is in contact with or near a hinge receiving portion having a locking hole or an edge of a hinge connection. 2. The hinge structure according to claim 1, wherein the hinge structure is located at a position indicated by the arrow. 3. A hinge pin is inserted through a hinge receiving portion of a first member made of a synthetic resin and a hinge connection portion of a second member to form a first member.
The member and the second member are rotatably pivotally connected to each other, a large-diameter portion is formed at a rear end of the hinge pin in the insertion direction, and a locking hole is formed at one of the hinge receiving portion and the hinge connection portion. A hinge structure in which the diameter part is engaged with the locking hole to prevent removal. The hinge pin is made of synthetic resin, and the large diameter part is formed by bulging in a part of the round bar-shaped pin body in the circumferential direction. A retaining portion is formed at a distance from the large diameter portion in the length direction of the hinge pin, and the retaining portion is in contact with or near the edge of the hinge receiving portion or the hinge connecting portion having the locking hole. A hinge structure characterized by being made to have. 4. An inclined surface is formed between the leading end of the large diameter portion and the pin body, and a retaining surface that is substantially perpendicular to the axial direction of the pin body is formed at the rear end of the large diameter portion. The hinge structure according to claim 1, wherein the hinge structure is formed.