KR20160105048A

KR20160105048A - Umbrella

Info

Publication number: KR20160105048A
Application number: KR1020150028203A
Authority: KR
Inventors: 황큰별
Original assignee: 황큰별
Priority date: 2015-02-27
Filing date: 2015-02-27
Publication date: 2016-09-06

Abstract

The umbrella according to the present invention is formed into a hollow shape having a predetermined length and has an adjustment groove formed along the direction of the umbrella; A support provided in the umbrella stand in the longitudinal direction; A cap connected to the upper end of the support; A lifting unit for lifting and lowering along the support frame; A plurality of main umbrellas fixed to the elevating portion and exposed to the outside between the upper end portion of the umbrella and the cap portion according to the ascending and descending of the elevating portion or housed inside the umbrella stand; An end portion of the main umbrella is rotatably fixed to the elevating portion and the other end of the auxiliary umbrella is movably connected within a predetermined range along the longitudinal direction of the main umbrella to limit the downward maximum turning range of the main umbrella; And an adjusting part connected to the umbrella cloth attached to the plurality of main umbrella fingers and the elevating part inside the umbrella through the adjusting groove, and elevating and lowering the elevating part along the adjusting groove.

Description

Umbrella {Umbrella}

The present invention relates to an umbrella, and more particularly, to an umbrella having an improved folding structure for non-use and improved convenience of storage.

Typical umbrellas are usually used and when folded, the outside of the damp umbrella cloth faces outward with rain. As a result, there is a problem that moisture remaining on the umbrella cloth is likely to be adhered to the clothes of the user holding the umbrella in a folded state or the clothes of the other persons adjacent to the user.

Prior arts related to a method of folding an umbrella in an inverted manner to solve this problem are disclosed in Korean Utility Model Registration No. 20-0278644, Korean Patent Laid-Open Publication No. 10-2005-0010091, and Registration No. 10-1229082.

However, most of these patents are exposed to the outside of the umbrella ribs and the cloth, so that the raindrops drop when entering the room, and the rainwater remaining on the umbrella cloth is buried in the case of using public transportation, causing inconvenience. In recent years, a lot of disposable rainproofing vinyl is used to prevent this, which is also inconvenient to use and expensive to dispose of as garbage. In addition, the above-mentioned patents provide a cause of frequent failures due to complicated structures such as using an auxiliary tibia or auxiliary shaft for folding upside down.

The present invention provides an umbrella having a structure capable of eliminating rainfall when not in use.

The present invention also provides an umbrella which can simplify the structure and enhance the durability.

The present invention also provides an umbrella having a structure capable of reinforcing the strength of the main umbrella.

Further, the main umbrella may be formed with a guide groove having a predetermined length along the longitudinal direction, and the auxiliary umbrella may be formed with a guide protrusion accommodated to be movable in the guide groove.

Wherein the main umbrella has a limiting protrusion protruding from the outer circumferential surface so as to limit the maximum outermost movable distance of the ring member, The end of the flesh may be provided with a hinge portion rotatably connected to the ring member.

At least one of the main umbrella and the auxiliary umbrella may be formed of a carbon fiber reinforced plastic (CFRP) material.

A bottom surface of the cap portion may include a first region formed to be inclined downwardly outwardly from a central axis; And a second region formed to be inclined upward toward the outside of the first region.

The cap member may be provided with a first magnet on a surface or an inner side of the cap member, and a metal member and a second magnet attached to the first magnet provided on the second region may be provided on the upper end of the umbrella member .

Further, a grip portion coupled to the lower end of the umbrella stand may be provided, and an elastic member may be provided between the elevation portion and the handle, wherein the elasticity increases when the elevation portion is lowered.

And a second groove portion formed in a circumferential direction of the outer circumferential surface from the first groove portion is formed on the outer circumferential surface of the elevating portion and the elasticity of the elastic member is increased The fixing protrusion may be formed at a position corresponding to the first groove portion in a state in which the elevating portion is lowered.

The lifting and lowering part may include at least one rubber ring groove that extends around the outer circumferential surface, and may include a rubber ring provided in the rubber ring groove.

The umbrella cloth may be formed of a material having elasticity and waterproof function.

Further, the umbrella cloth may be formed of an elastic material cloth formed with a waterproof coating layer.

The cap portion is provided with a shaft portion extending downward from the center of the bottom portion and an extension portion formed at a lower end portion of the shaft portion so as to expand the outer diameter of the shaft portion. And the inlet of the accommodating portion is formed to have a diameter smaller than the diameter of the expanding portion so as to restrict the departure of the expanding portion.

According to the present invention, the umbrella cloth and the umbrella cloth are positioned inside the umbrella frame when not in use, thereby preventing the rainwater from falling on the floor, and minimizing the inconvenience that the rainwater is buried in the rainwater even when using public transportation.

Further, according to the present invention, it is possible to minimize the deformation of the umbrella and the malfunction of the umbrella during operation by supporting the main umbrella with high elasticity and high strength.

1 is a perspective view showing a folded state of an umbrella when not in use according to an embodiment of the present invention.
2 is a perspective view showing an open state of the use state of the umbrella according to the embodiment.
3 is an exploded perspective view showing an umbrella according to an embodiment.
4 is a bottom perspective view showing a state of a cap unit according to an embodiment.
5 is a longitudinal sectional view showing a coupling state of a cap portion according to an embodiment.
6 is a perspective view showing a state of a lifting unit according to an embodiment.
7 is a longitudinal sectional view showing a coupling relationship of the elevating portion according to an embodiment.
8 is a perspective view schematically showing a state of a main umbrella and an auxiliary umbrella according to an embodiment.
Figs. 9 and 10 are cross-sectional views showing the configuration and coupling relationship of the main umbrella and the auxiliary umbrella according to different embodiments, respectively.
11 to 13 are sectional views sequentially showing the operating states of the umbrella.
14 and 15 are a perspective view showing a lifting portion according to another embodiment and a cross-sectional view showing a coupling relationship therebetween.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the absence of special definitions or references, the terms used in this description are based on the conditions indicated in the drawings. The same reference numerals denote the same members throughout the embodiments. For the sake of convenience, the thicknesses and dimensions of the structures shown in the drawings may be exaggerated, and they do not mean that the dimensions and the proportions of the structures should be actually set.

A schematic view of an umbrella according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. FIG. 1 is a perspective view illustrating a folded state of an umbrella according to an embodiment of the present invention, FIG. 2 is a perspective view showing an open state of an umbrella according to an embodiment, and FIG. And Fig.

1, the handle 110, the adjuster 120, the umbrella 130, and the cap 140 are observed in the umbrella 10 according to an embodiment of the present invention in an unused state. The umbrella stand 130 is formed in a hollow tube shape having a predetermined length and an adjusting groove 131 is formed along the longitudinal direction. The handle 110 is provided at the lower end of the umbrella stand 130 and is used to grasp the umbrella 10 by the user. The adjustment portion 120 is formed in a ring shape and is lifted along the adjustment groove 131 in a state of being fitted to the outside of the umbrella stand 130. The cap unit 140 is provided at the upper end of the umbrella stand 130 to seal the upper end of the umbrella stand 130. The umbrella 10 according to the present embodiment is not exposed to the outside of the umbrella cloth in an unused state and is stored inside the umbrella stand 130. [

The umbrella bed 150 and the umbrella cloth 170 may flow out between the cap unit 140 and the umbrella stand 130 when the adjusting unit 120 is lifted along the umbrella stand 130 as shown in Fig. .

Each component will be described in detail below.

3, the umbrella 10 according to the present embodiment includes a handle 110, a support 190, a lift 180, an umbrella 130, an adjuster 120, and a cap 140 And the like.

First, the handle 110 is similar to the handle included in the conventional umbrella. A fastening hole 119 is formed at the upper end of the handle 110 to engage with the support 190. The coupling structure of the handle 110 and the support 190 is not limited, and various structures other than the coupling structure shown in FIG. 3 can be realized.

The support base 190 is coupled to the upper end of the handle 110 as described above. The support member 190 may be formed into a rod shape or a tubular shape having a predetermined length. And guides the elevating portion 180 of the support table 190 to be elevated and lowered.

The lifting and lowering part 180 is provided with a through hole 181 penetrating in the central axis direction and the support base 190 is inserted into the through hole 181 and penetrates in the central axis direction. The lifting and lowering part 180 functions to raise or lower the supporting table 190 in a state where the umbrella holder is connected. The specific structure of the lifting portion 180 and the connection relation and the structure with the peripheral constituting portions will be described later in detail.

The cap unit 140 is connected to the upper end of the support member 190. A magnet 141 is provided on the bottom surface of the cap unit 140 and attached to the upper part of the umbrella stand 130 or separated by an external force to open and close the upper end of the umbrella stand 130.

The umbrella stand 130 is formed into a hollow cylindrical or polygonal tubular shape. The umbrella stand 130 functions as a case for containing the support stand 190 and the elevation portion 180 so as not to be exposed to the outside. The upper end of the umbrella stand 130 may be made of a metal material so as to be adherable to the magnet 141 of the cap unit 140 described above or another magnet having a magnet and attracting force of the cap unit 140 formed at the upper end of the umbrella stand 130 Respectively. With such a structure, the upper end of the umbrella stand 130 can be opened and closed by the cap portion 140 by the magnetic force.

The adjustment groove 131 is formed along the longitudinal direction of the umbrella stand 130. The adjustment groove 131 is formed in an incised shape penetrating the inside and the outside of the umbrella stand 130. The extension groove 131 is formed at a lower end of the adjustment groove 131 by a predetermined length in the circumferential direction of the umbrella stand 130.

The regulating portion 120 is formed of a ring-shaped member. The adjusting portion 120 is formed with a connecting portion 121 protruding from the inner circumferential surface in the direction of the central axis. The connecting portion 121 is inserted into the umbrella frame 130 through the adjusting groove 131 or the extending groove 1311 and is connected to the elevating portion 180. When the adjusting part 120 is moved to the upper part of the umbrella stand 130 by connecting the adjusting part 120 and the elevating part 180 by the connecting part 121, the elevating part 180 is also lifted from the inside of the umbrella stand 130 The elevation part 180 is also lowered integrally with the inner side of the umbrella stand 130 by moving the adjusting part 120 to the lower part of the umbrella stand 130. At this time, the connection portion 121 is moved through the adjustment groove 131 or the extension groove 1311. When the connecting portion 121 moves along the adjusting groove 131, the adjusting portion 120 and the elevating portion 180 can be raised or lowered along the umbrella 130. When the connecting portion 121 is in the extended groove 1311 It is possible to prevent the adjusting part 120 and the elevating part 180 from rising or falling and fixing them.

The cap portion will be described in detail with reference to Figs. 4 and 5. Fig. FIG. 4 is a bottom perspective view illustrating a cap unit according to an embodiment of the present invention, and FIG. 5 is a vertical cross-sectional view illustrating an assembled state of the cap unit according to an embodiment.

The cap part 140 is a constituent part for opening and closing the upper end of the umbrella stand as described above. A shaft portion 143 is provided at the lower end of the cap portion 140 as shown in FIG. The shaft portion 143 is formed to extend downward from the lower end center of the cap portion 140. The lower end of the shaft portion 143 is formed with an extended portion 145 having an expanded outer diameter.

Referring to FIG. 5, the bottom surface of the cap unit 140 can be divided into two regions. The bottom surface of the cap part 140 has a first area A1 inclined downward from the center toward the outside and a second area A2 located outside the first area A1 and inclined upward toward the outside.

The first region A1 is a region for pressing the main umbrella to contact the upper end of the elevating portion to be described later and is preferably formed so as to be inclined downward toward the outer side in order to press the main umbrella, desirable. The second area A2 is formed so as to correspond to the shape of the upper end of the umbrella stand to seal the upper end of the umbrella stand. At this time, the magnet 141 may be included so that it can be detached and attached to the umbrella stand. In addition, the second area A2 is preferably formed so as to be inclined upward toward the outside so that the main umbrella is bent outward so that the main umbrella is exposed to the outside.

The shaft 143 may be fixedly coupled with the support 190. In this embodiment, the shaft 143 may be formed to have a structure that can be elevated by a predetermined height. Specifically, a receiving portion 195 is formed in the upper end of the support base 190 to receive a part of the shaft 143 and the entire extension 190. The inlet of the receiving portion 195 is narrower than the diameter of the extending portion 190, thereby limiting the height at which the cap portion 140 can rise.

The elevating portion will be described with reference to Figs. 6 and 7. Fig. FIG. 6 is a perspective view showing a state of a lifting unit according to an embodiment, and FIG. 7 is a longitudinal sectional view showing a coupling relationship of a lifting unit according to an embodiment.

The elevating part 180 according to the present embodiment is divided into a cylindrical shape having a lower end and an upper part having a truncated cone shape. At the lower portion of the elevating portion 180, a regulating portion receiving groove 187 is formed on the outer peripheral surface. The adjusting portion receiving groove 187 receives the connecting portion 121 protruded to the inside of the adjusting portion 120 and is connected to the adjusting portion 120 and the elevating portion 180 so as to move integrally.

The rubber ring receiving grooves 188 are formed in the direction in which the center outer peripheral surface of the elevating portion 180 is rotated. A ring-shaped rubber ring 189 is fitted in the rubber ring receiving groove 188. The rubber ring 189 reduces or keeps the frictional force with the umbrella stand 130 so as to prevent the elevation portion 180 from tilting or twisting.

A first hinge portion 183 is formed on the upper portion of the elevating portion 180. The first hinge portion 183 is formed in a groove shape opened to the upper side and the side face and accommodates one end of the main umbrella body 150 so that the main umbrella body 150 is vertically rotatable.

Second hinge parts 185 are formed below the first hinge parts 183. The second hinge part 185 is formed in a groove shape opened to the side of the lift part 180 and accommodates one end of the auxiliary umbrella body 160 so that the auxiliary umbrella body 160 can be turned upside down.

As described above, the lifting portion 180 is formed with a through hole 181 passing through in the central axis direction. The support base 190 is inserted through the through hole 181.

7, in a state in which the main umbrella body 150 is lifted, the cap portion 140 is separated from the umbrella stand 130 and raised so that the main umbrella body 150 is pressed by the bottom surface of the cap portion 140 Downward. At this time, the auxiliary umbrella body 160 limits the downward maximum angle at which the main umbrella body 150 rotates.

The main umbrella and auxiliary umbrella fingers will be described with reference to FIGS. 8 to 10. FIG. FIG. 8 is a perspective view schematically showing a state of a main umbrella and an auxiliary umbrella according to an embodiment, and FIGS. 9 and 10 are cross-sectional views showing a configuration and a coupling relationship of a main umbrella and an auxiliary umbrella according to another embodiment .

The main umbrella body 150 is a constituent part constituting a skeleton to which an umbrella cloth is attached as described above. At one end of the main umbrella body 150, a first hinge fastening portion 151 for fastening to the first hinge portion described above is formed. Further, a guide groove 159 formed along the longitudinal direction is formed at a position adjacent to the first hinge fastening portion 151 of the main umbrella body 150. The guide groove 150 receives one end of the auxiliary umbrella body 160 and guides the auxiliary umbrella body 160 to be movable within a certain range. One end of the auxiliary umbrella body 160 is formed with a second hinge fastening portion 161 for fastening to the second hinge portion described above. The other side of the second hinge fastening portion 161 is formed with a guide protrusion 153 which is inserted into the guide groove 159 and moves along the guide groove 159.

The auxiliary umbrella body 160 is positioned below the main umbrella body 150 as shown in FIG. 9 and serves to limit the angle at which the main umbrella body 150 is rotated downward to the maximum. 9 (a), the end of the auxiliary umbrella body 160 reaches and reaches the end of the guide groove 159 at the maximum downward turning angle of the main umbrella body 150, ) To prevent further downward pivoting. 9 (b), when the main umbrella body 150 rotates upward, the end portion of the auxiliary umbrella body 160 moves along the guide groove 159, so that the main umbrella body 150 rotates smoothly .

Meanwhile, the main umbrella fish 150 and the bonito fish fish 160 can be connected in various ways and structures. For example, as shown in FIG. 10, a ring-shaped ring member 155 fastened to be movable in the longitudinal direction of the main umbrella body 150 may be provided on the outer circumferential surface of the main umbrella body 150. At this time, a third hinge part 157 is formed on one side of the ring member 155, to which the auxiliary umbrella body 160 is fastened.

A protrusion 157 is formed at one point of the main umbrella body 150. The projecting portion 157 is formed in such a shape that the outer diameter of at least a part of the outer peripheral surface of the main umbrella body 150 is enlarged. The protrusion 157 limits the maximum point at which the ring member 155 can be moved.

10 (a) and 10 (b), when the main umbrella body 150 is rotated upward or downward, the ring member 155 is inserted into the main umbrella body 150 in a state of being connected to the auxiliary umbrella body 160, And the ring member 155 contacts and supports the protruding portion 157 in the downward maximum rotation state of the main umbrella body 150 so that the main umbrella body 150 is prevented from further downward turning do.

The operation method and the state of the umbrella according to the present embodiment will be described with reference to Figs. 11 to 13. Fig. 11 to 13 are sectional views sequentially showing the operating states of the umbrella.

11, the cap portion 140 comes into contact with the upper end portion of the umbrella stand 130 by the magnetic force of the magnet 141 in a normal state. At this time, the elevation part 180 is positioned adjacent to the umbrella bed 110, and the main umbrella stand 150 and the auxiliary umbrella stand 160 are provided inside the umbrella stand 130 and are not exposed to the outside Do not.

Referring to FIG. 12, in the initial stage for using the umbrella, the user lifts the adjustment unit 120 to the upper side of the umbrella stand 130. At this time, the elevating portion 180 integrally connected to the adjusting portion 120 is raised. The main umbrella fins 150 and the auxiliary umbrella fins 160 fastened to the elevating portion 180 rise together with the elevating portion 180 rising. As the main umbrella body 150 is raised, the end of the main umbrella body 150 is lifted after separating the cap portion 140 from the umbrella stand 130. Thereafter, the main umbrella body 150 flows out between the cap portion 140 and the umbrella stand 130 and is gradually exposed to the outside.

13, the main umbrella body 150 is pushed downward by the bottom surface of the cap portion 140 in a process in which the lifting portion 180 is finally raised and contacts the bottom surface of the cap portion 140. As shown in FIG. At this time, the auxiliary umbrella body 160 can increase the structural stability of the entire umbrella by restricting and supporting the maximum downward turning angle of the main umbrella body 150.

After the use of the umbrella is finished, the umbrella can be folded and stored through the reverse process of this procedure. That is, the control unit 120 is lowered so that the main umbrella fins 150 and the auxiliary umbrella fins 160 are rotated upward. The main umbrella fuselage 150 and the auxiliary umbrella fuselage 160 are gradually accommodated to the inside of the umbrella stand 130 by gradually lowering the adjusting unit 120 and finally the main umbrella stand 150 and the main umbrella stand 160 The entirety of the umbrella cloth and the auxiliary umbrella body 160 attached to the umbrella stand 150 are accommodated in the umbrella stand 130. At this time, the cap stand 140 rotates the upper end of the umbrella stand 130 by the magnetic force of the magnet 141 It is sealed. In this storage state, the wet umbrella cloth or the like is not exposed to the outside during use, thereby minimizing the possibility of contamination of the room or inconvenience of others.

An umbrella according to another embodiment will be described with reference to Figs. 14 and 15. Fig. 14 and 15 are a perspective view showing a lifting portion according to another embodiment and a cross-sectional view showing a coupling relationship therebetween.

The umbrella according to this embodiment has an arrangement and structure that uses the elasticity of an elastic member or the like in the initial process of unfolding the umbrella like a semi-automatic umbrella.

Specifically, the elevating portion 180a according to the present embodiment includes a first groove portion 186a formed on the lower outer circumferential surface in the direction of the central axis from the lower end thereof, and a second groove portion 186b formed on the second groove portion 184a formed in the circumferential direction of the outer circumferential surface from the first groove portion 186a. (186b) is formed. At this time, fixing ribs 138 inserted into the first groove portion 186a and the second groove portion 186b are formed on the inner peripheral surface of the umbrella stand 130.

When the elevating part 180a is lowered, the fixing protrusion 138 is inserted into the first groove part 186a. Thereafter, when the elevating part 180 is rotated about the central axis, 2 groove portion 186b to prevent the lift portion 180a from being raised or lowered arbitrarily.

The elevation portion 180a is lowered so that the elasticity of the elastic member 188 is increased so that the fixing protrusion 138 formed at the position corresponding to the first groove portion is inserted into the first groove portion 186a and the second groove portion 186b In this case, it is fixed in a state in which the elasticity for raising the lifting portion 180a is increased. When the fixing protrusion 138 is released from the second groove portion 186b through the first groove portion 186a in a reverse process from this state, the elevation portion 180a is raised by the elasticity so that a semi-automatic umbrella can be realized have.

The elastic member 188 may be attached to the lower end of the lift portion 180a or may be attached to the upper end of the handle portion 110. [ That is, the elastic member 188 is provided between the grip portion 110 and the lift portion 180a to provide elasticity for lifting the lift portion 180a.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. have.

100: Umbrella
110: Handle portion
120:
130: umbrella stand
140: cap part
150: Lord to buy umbrellas
160: buy secondary umbrella
170: Umbrella cloth
180:
190: Support

Claims

An umbrella which is formed in a hollow shape having a predetermined length and in which an adjustment groove is formed along the longitudinal direction;
A support provided in the umbrella stand in the longitudinal direction;
A cap connected to the upper end of the support;
A lifting unit for lifting and lowering along the support frame;
A plurality of main umbrellas fixed to the elevating portion and exposed to the outside between the upper end portion of the umbrella and the cap portion according to the ascending and descending of the elevating portion or housed inside the umbrella stand;
An end portion of the main umbrella is rotatably fixed to the elevation portion and the other end is connected to be movable within a predetermined range along the longitudinal direction of the main umbrella to limit the downward maximum turning range of the main umbrella;
An umbrella cloth attached to the plurality of main umbrella fins; And
And an adjusting unit connected to the elevating unit inside the umbrella unit through the adjusting groove and moving up and down along the adjusting groove to elevate the elevating unit.

The method according to claim 1,
Wherein the main umbrella has a guide groove having a predetermined length along the longitudinal direction, and the auxiliary umbrella has a guide protrusion accommodated movably in the guide groove.

The method according to claim 1,
And a ring member coupled to an outer circumferential surface of the main umbrella and moving in the longitudinal direction,
Wherein the main umbrella has a limiting protrusion protruding from the outer circumferential surface so as to limit a maximum outermost movable distance of the ring member,
And an end of the auxiliary umbrella has a hinge portion rotatably connected to the ring member.

The method according to claim 1,
Wherein at least one of the main umbrella and the auxiliary umbrella is formed of a CFRP (carbon fiber reinforced plastic) material.

The method according to claim 1,
A bottom surface of the cap portion has a first region formed to be inclined downwardly outward from a central axis; And
And a second region formed to be inclined upward toward the outside of the first region.

6. The method of claim 5,
Wherein a first magnet is provided on a surface or inside of a second region of the cap portion,
And an umbrella having one of a metal member and a second magnet which can be attached to the first magnet provided in the second region.

The method according to claim 1,
A grip portion coupled to a lower end of the umbrella stand,
Wherein an umbrella is provided between the inner side of the umbrella stand and the elevation portion and the handle, the elasticity of which is increased when the elevation portion is lowered.

8. The method of claim 7,
And a second groove portion formed in a circumferential direction of the outer circumferential surface from the first groove portion is formed on the outer circumferential surface of the elevating portion,
And an inner circumferential surface of the umbrella support has a fixing protrusion formed at a position corresponding to the first groove in a state in which the elevation portion is lowered to increase the elasticity of the elastic member.

The method according to claim 1,
Wherein the lifting and lowering portion includes at least one rubber ring groove that extends around the outer circumferential surface and includes a rubber ring provided in the rubber ring groove.

The method according to claim 1,
Wherein the umbrella cloth is formed of a material having an elastic and waterproof function.

The method according to claim 1,
Wherein the umbrella cloth is formed of an elastic material cloth having a waterproof coating layer formed thereon.

The method according to claim 1,
The cap portion includes a shaft portion extending downward from the center of the bottom surface and an extension portion formed at a lower end portion of the shaft portion so as to expand the outer diameter,
Wherein the supporting base has a receiving portion for receiving a part of the shaft and an entirety of the extending portion at an upper end thereof,
Wherein an inlet of the accommodating portion is formed to have a diameter smaller than a diameter of the expanding portion to restrict the escape of the expanding portion.