JP5411750B2 - cap - Google Patents

Description

  The present invention relates to a cap that is attached to a container that stores contents such as beverages.

  As a cap to be attached to a container for storing a content such as a beverage, a cap that can confirm the presence or absence of the opening is widely used. As such a cap, a disk-shaped top plate, and a side wall portion formed on the inner peripheral surface of a female screw portion that extends from the outer peripheral edge of the top plate to one side in the axial direction and is screwed into the male screw portion of the container mouth portion. And a tamper-evidence band that is connected to the edge of the cap body via a breakable bridge and has a locking portion on the inside that locks to the bead portion of the container mouth. It has been.

  In the cap described above, when the locking portion is locked to the bead portion of the container mouth portion by the opening operation from the state where the cap is attached to the container mouth portion, a tensile force is applied to the bridge so that the bridge is The cap body and the tamper-evidence band are separated from each other so that it can be easily confirmed by visual confirmation whether or not the opening operation has been performed.

  Patent Document 1 and Patent Document 2 include a cap that allows the tamper evidence band not only to be separated from the cap body by forming a split in the tamper evidence band, but also to be removed from the container mouth. Have been described. Among them, in the cap of Patent Document 1, a large number of bendable fins formed on the inner peripheral surface of the tamper evidence band give the tamper evidence band an opening resistance, and this resistance force breaks the bridge. The cap body and the tamper evidence band are separated from each other. In the cap of Patent Document 2, a plurality of locking flap pieces formed on the inner peripheral surface of the side wall portion are locked to the locking jaw portion of the container mouth portion in accordance with the opening operation, and the cap body and the tamper evidence. The bands are separated from each other.

JP-A-6-156516 JP-A-61-2355

  However, in the cap of Patent Document 1, opening resistance is generated in the tamper evidence band by the fin, and a large rotation angle of the cap is required until sufficient force to break the bridge acts on the bridge. Become. Therefore, the user must perform a large opening operation, which is not convenient. Furthermore, if sufficient resistance to opening is not obtained, it is possible that only a part of the bridge can be broken and the cap body cannot be separated from the tamper evidence band. On the other hand, in the cap of Patent Document 2, there is a case where the locking flap piece is deformed or there is a gap between the locking flap piece and the locking jaw, so that the bridge is broken. A large rotation angle is required. Therefore, the user must perform a large opening operation even in this cap.

  Accordingly, an object of the present invention is to provide a cap that can reliably separate the tamper evidence band from the cap body even with a small opening operation.

In order to achieve the above object, the following technical measures were taken.
That is, the cap of the present invention has a top plate and a side wall formed on the inner peripheral surface of the top plate and a cap screw portion that extends from the outer peripheral edge of the top plate to one side in the axial direction and is screwed into the container screw portion of the container mouth A cap body comprising a cap body, and a tamper evidence band that is connected to an end edge of the cap body via a breakable bridge and has a locking portion that locks with a bead portion of the container mouth portion. Then, by the opening operation from the state attached to the container mouth portion, the locking portion is locked to the bead portion, a tensile force is applied to the bridge, and the bridge is broken. In the cap in which the cap body and the tamper evidence band are separated from each other, the tamper evidence band is attached to the front of the tamper evidence band in accordance with the opening operation. Radially expansible mechanism for applying a shearing force to the bridge by expanding pressing toward the vicinity of the bridge outward and is characterized in that is provided.

  According to the cap of the present invention, since the vicinity of the bridge in the tamper evidence band is pushed outward by the diameter expansion mechanism and a shearing force is applied to the bridge, the cap is opened when the plug opening operation is performed. A tensile force and a shearing force act simultaneously on the bridge connecting the main body and the tamper evidence band. For this reason, the bridge can be reliably broken at a stage where the rotation angle of the cap is small.

The diameter-expansion mechanism includes an elastically bendable elastic piece standing inwardly at an end portion on the bridge side on the inner peripheral surface of the tamper evidence band, and the elastic piece is an outer periphery of the container mouth portion. Examples include a configuration in which the shearing force is applied by abutting the surface and bending elastically.
By including such an elastic piece in the diameter expansion mechanism, since the shearing force is applied to the bridge early when the opening operation is started, the rotation angle of the cap for breaking the bridge is reduced. be able to.

The elastic piece has a length that is always in contact with the outer peripheral surface of the container mouth, and when the closing operation is performed, the elastic piece is tilted so as not to resist the outer peripheral surface of the container mouth, and the opening operation is not performed. When it is performed, it is preferable to stand up in a direction to rise up against the outer peripheral surface of the container mouth.
In this case, as soon as the opening operation is started, the elastic piece is elastically bent and the shearing force is applied to the bridge at an early stage, so that the rotation angle of the cap for breaking the bridge can be reduced. . Furthermore, when the closing operation is performed, the resistance by the elastic piece can be reduced, so that the smooth closing is possible.

  It is preferable that the elastic piece has a strength that allows the elastic piece to rise up to a substantially upright state with respect to the inner peripheral surface of the tamper evidence band when the opening operation is performed. Since the elastic piece has such strength, the elastic piece rises up to a substantially upright state with respect to the outer peripheral surface, so that the tamper evidence band can be greatly expanded outward. Thereby, a larger shearing force can be applied to the bridge.

  It is preferable that the elastic piece is erected at a position corresponding to the bead portion of the container mouth portion. When the elastic piece is erected at a position corresponding to the bead portion, the elastic piece bends elastically in a relatively narrow space between the tamper evidence band and the bead portion, so that a greater shearing force acts on the bridge. Can be made.

  Various configurations can be adopted as the elastic piece. For example, the elastic piece may be formed in an elongated cross-sectional square shape, and a plurality of elastic pieces may be provided at predetermined intervals on the inner peripheral surface of the tamper evidence band.

  As described above, according to the present invention, the tensile force and the shearing force act simultaneously on the bridge that connects the side wall portion and the tamper evidence band with the opening operation, so that the bridge is broken by a small opening operation. The tamper evidence band can be reliably separated from the cap body.

It is sectional drawing in the state which mounted | wore the container opening part of the container which concerns on one Embodiment of this invention, and the part left with a broken line is a partial side view of a cap. It is sectional drawing of a cap. It is a perspective view of an elastic piece and its vicinity part. It is the sectional view on the AA line of FIG. It is sectional drawing corresponding to the AA line of FIG. 2 in the state which mounted | wore the container mouth part with the cap. It is sectional drawing corresponding to the AA line of FIG. 2 at the time of performing the opening operation. It is principal part sectional drawing in the state which started opening operation. It is principal part sectional drawing in the state which further advanced the opening operation.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the cap 1 according to an embodiment of the present invention attached to the container mouth 51 of the container 50, and FIG. 2 is a cross-sectional view of the cap 1. In the following description, the upper and lower sides of FIG. The cap 1 is used by being attached to a container mouth 51 of a container 50 made of a synthetic resin such as a plastic bottle as shown in FIG. The cap 1 is integrally formed of polypropylene by compression molding or injection molding. The top plate 2 is located at the top, and the side wall portion 3 extends downward from the outer peripheral edge of the top plate 2. A tamper evidence band 4 connected to the lower end edge of the side wall 3 is provided. In addition, the raw material which forms the cap 1 is not specifically limited, Polyethylene, polylactic acid, etc. other than the polypropylene used by this embodiment are used suitably.

  For example, as shown in FIG. 1, the container mouth portion 51 to which the cap 1 of this embodiment is attached has a cylindrical main body portion 52 formed with substantially the same diameter from the upper end to the lower end, and an outer peripheral surface of the main body portion 52. The formed male screw portion 53, the bead portion 54 having a diameter increased below the male screw portion 53, and a support ring (neck ring) having a diameter larger than that of the bead portion 54 below the bead portion 54. 55. Of these, the bead portion 54 includes a bead body 56 positioned on the lower side and a reduced diameter portion 57 positioned on the upper side of the bead body 56 and reducing in diameter toward the upper side.

  A cap body 15 is constituted by the top plate 2 and the side wall 3, and the top plate 2 is formed in a disk shape having a required dimension, and the container 50 is sealed inside the top plate 2. Packing 20 is provided. The packing 20 includes a disk-like plate-like portion 21 along the lower surface 2 a of the top plate 2, an annular side seal portion 22 that is bent downward from the outer peripheral portion 21 a of the plate-like portion 21, and a lower portion from the lower surface 21 b of the plate-like portion 21. And a cylindrical middle leg portion 23 extending toward the top. The side seal portion 22 enters between the upper end portion 51 a of the container mouth portion 51 and the side wall portion 3 of the cap 1, and the middle foot portion 23 is in close contact with the inner surface n of the upper end portion 51 a of the container mouth portion 51. The multiple seal structure formed by these seals the container mouth portion 51 satisfactorily, so that the air tightness inside the container 50 is maintained high.

  The side wall part 3 of the cap body 15 is formed in a cylindrical shape having a required dimension, and the female thread part 5 to be screwed into the male thread part 53 of the container mouth part 51 is formed on the inner peripheral surface 3a. Is formed. The female screw portion 5 is composed of a plurality of protruding portions 5A provided continuously at a predetermined interval in the circumferential direction so that a liquid material can pass in the vertical direction. A knurled groove 6 extending in the vertical direction is formed on the outer peripheral surface 3 b of the side wall 3.

  A plurality of bridges 7 are formed at predetermined intervals along the circumferential direction at a boundary portion between the side wall portion 3 and the tamper evidence band 4. These bridges 7 connect the cap body 15 and the tamper evidence band 4 to each other, and break when pulled by a predetermined force. The tamper evidence band 4 is formed in a cylindrical shape whose diameter is slightly increased as it goes downward. A locking portion 8 is positioned inside the tamper evidence band 4, and the locking portion 8 extends from the lower end portion 4 a of the tamper evidence band 4 so as to be folded obliquely upward and inward.

  The locking portion 8 is formed so as to be continuous in the circumferential direction with a required thickness. The wall portion 9 extends to a position immediately below the bead portion 54 while being attached to the container mouth portion 51. It is comprised with the internal protrusion 10 folded in the shape of a cross-section toward the direction. The inner protrusion 10 is composed of two triangular pieces 10 a and is configured such that a ridge line portion 10 b where the two triangular pieces 10 a are joined to each other is inclined inwardly among the locking portions 8. The ridgeline portion 10b, each triangular piece 10a, and the boundary line portion 10c of the wall surface portion 9 intersect at the lower end 10d of the inner projection 10, thereby forming an inverted triangular pyramid-shaped space 11 that narrows downward. ing. The locking portion 8 configured as described above has a bellows shape continuous in the circumferential direction as a whole, and can be elastically deformed inward, outward and downward. And this latching | locking part 8 is located in the substantially lower side of the bead part 54 in the state with which the container mouth part 51 was mounted | worn, and the upper end 8a of the said latching | locking part 8 is the latching surface of the bead body 56 by opening operation. 56a (see FIG. 1).

  In the vicinity of the bridge 7 formed at the boundary between the side wall portion 3 and the tamper evidence band 4, a diameter increasing mechanism 12 for expanding the tamper evidence band 4 is formed. The diameter expansion mechanism 12 includes a plurality of elastic pieces 13 provided immediately below the bridge 7, and the plurality of elastic pieces 13 are annularly connected to the edge portion 4 c on the bridge 7 side on the inner peripheral surface 4 b of the tamper evidence band 4. It is provided at a required interval in the circumferential direction via the portion 14. In addition, the aspect which provides the some elastic piece 13 in the internal peripheral surface 4b of the tamper evidence band 4 may be what kind of thing, and without providing the cyclic | annular part 14 as shown in FIG. 3, the some elastic piece 13 is tamper evidence. You may provide directly in the internal peripheral surface 4b of the band 4. FIG.

  FIG. 3 is a perspective view of the vicinity of the elastic piece 13 in the cap 1, and FIG. 4 is a cross-sectional view taken along line AA in FIG. Each elastic piece 13 is formed in an elongated cross-sectional square shape and extends inwardly from the edge portion 4 c of the tamper evidence band 4. The vertical position of each elastic piece 13 is also a position corresponding to the bead portion 54 of the container mouth portion 51 when the cap 1 is attached to the container mouth portion 51. The direction in which each elastic piece 13 extends is the direction of an angle θ of about 30 ° inward from a tangent line passing through the root of each elastic piece (see FIG. 3).

  FIG. 5 is a cross-sectional view corresponding to the line AA in FIG. 2 in a state where the cap 1 is attached to the container mouth portion 51. Since each elastic piece 13 formed of synthetic resin is formed in an elongated shape, it can be elastically bent. Each elastic piece 13 has a length that always comes into contact with the bead body 56 of the bead portion 54 of the container mouth portion 51 in a state where the cap 1 is attached to the container mouth portion 51. Therefore, when the cap 1 is attached to the container mouth portion 51 in the closing direction U, the distal end side portion 13a of each elastic piece 13 comes into contact with the outer peripheral surface 56b of the bead body 56, and each elastic piece 13 The bend body 56 is bent so as to fall down while being pushed.

  While the cap 1 is attached to the container mouth portion 51, the plurality of elastic pieces 13 are always pushed by the bead body 56 and fall down. Since each elastic piece 13 has elasticity, it will return to the original state shown in FIG. 4 if there is nothing to hold down each elastic piece 13. In the following description, when each elastic piece 13 is in the no-load state shown in FIG. 4, it is referred to as a steady state, and a state where the elastic piece 13 has fallen from the steady state as described above is a tilted state. The state of getting up from is called the state of getting up.

  FIG. 6 shows an example of the state of the plurality of elastic pieces 13 when the cap 1 is being opened. When the capping operation is performed, that is, when the cap 1 is rotated in the capping direction U (see FIG. 5), the plurality of elastic pieces 13 fall down so as not to resist the outer peripheral surface 56b of the bead body 56 of the container mouth portion 51. Bend and maintain a tilted state. When the opening operation is performed, that is, when the cap 1 is rotated in the opening direction T (see FIG. 6), some of the elastic pieces 13A in the tilted state are in the container mouth. The tip end portion 13a cannot be slid by the outer peripheral surface 56b due to frictional force or the like with the outer peripheral surface 56b of the bead body 56 of the portion 51, and is guided to the outer peripheral surface 56b. Then, a part of the elastic pieces 13 </ b> A starts to be pushed by a force that turns the cap 1 against the outer peripheral surface 56 b of the bead body 56. Since each elastic piece 13 is disposed in a narrow gap R between the inner peripheral surface 4b of the tamper evidence band 4 and the outer peripheral surface 56b of the bead body 56, when a part of the elastic pieces 13A starts the plug opening operation. It is bent so as to rise up elastically immediately, and shifts from a tilted state to a raised state.

  In the example of FIG. 6, the elastic piece 13A of about half (the left half of FIG. 6) of the plurality of elastic pieces 13 is shifted from the tilted state to the raised state. Further, the drawing of each elastic piece 13A in the left half of FIG. 6 also shows the behavior of one elastic piece 13 away from the tilted state from the upper elastic piece 13Aa to the lower elastic piece 13Ac. Each elastic piece 13 of the present embodiment has a strength that allows it to rise up to a substantially upright state with respect to the inner peripheral surface 4b of the tamper evidence band 4 when the opening operation is performed. Therefore, some of the elastic pieces 13Aa gradually rise from the tilted state when the opening operation is started to become the elastic pieces 13Ab in a substantially standing state, and as the opening operation further proceeds, the side opposite to the tilted state The elastic piece 13Ac is collapsed. The plurality of elastic pieces 13 do not necessarily have the form shown in FIG. 6, and take various behaviors depending on the configuration of the plurality of elastic pieces 13. When the plurality of elastic pieces 13 behave as described above, the tamper evidence band 4 is eccentrically or locally deformed, or locally deformed while being eccentric. The case where the tamper evidence band 4 is locally deformed while being decentered will be described with reference to the example of FIG. 6. The tamper evidence band 4 is decentered toward the outer G side where the elastic piece 13Ab in the substantially standing state is located, At the same time, the portion corresponding to the elastic piece 13Ab in the tamper evidence band 4 and the vicinity thereof are locally deformed toward the outer side G. Here, when the tamper evidence band 4 is eccentric to the outward G side, the distance between the portion corresponding to the substantially standing elastic piece 13Ab in the tamper evidence band 4 and the outer peripheral surface 56b of the bead body 56 increases. Only the distance between the elastic piece 13Ab in the tamper evidence band 4 and the portion corresponding to the elastic piece 13 on the right side in FIG. 6 at the symmetrical position and the outer peripheral surface 56b of the bead body 56 is reduced.

  Next, the operation of each part when the cap 1 is attached to the container mouth part 51 by the closing operation and when the cap main body 15 is separated from the tamper evidence band 4 by the opening operation will be described.

(Capping operation)
When the cap 1 is rotated in the closing direction U, the cap 1 is depressed by both the screw parts 5 and 53, and the container 8 is elastically deformed from the lower side to the upper side together with the cap part 1 Get over the male threaded portion 53 and the bead portion 54 of the mouth 51. When the locking portion 8 gets over the bead portion 54, the locking portion 8 is guided by the reduced diameter portion 57 of the bead portion 54 and smoothly gets over the bead portion 54. The locking portion 8 elastically returns to the original shape shown in FIG. 1 when it has passed over the bead portion 54. Further, the plurality of elastic pieces 13 are guided to the bead body 56 while gradually increasing the amount of bending at the reduced diameter portion 57 of the bead portion 54, and are elastically bent to the state shown in FIG. When the locking portion 8 is fitted below the bead portion 54, the plurality of elastic pieces 13 are brought into contact with the bead body 56 of the bead portion 54, and both the screw portions 5 and 53 are screwed together. Installation is complete.

(Opening operation)
FIG. 7 is a cross-sectional view of the main part in a state where the opening operation of the cap 1 is started, and FIG. 8 is a cross-sectional view of the main part in a state where the opening operation of the cap 1 is further advanced. When the cap 1 starts to rotate in the opening direction T of FIG. 6, the cap 1 starts to rise upward, and the locking portion 8 is locked to the locking surface 56 a of the bead body 56. Therefore, the tamper evidence band 4 cannot go further upward, and the tensile force H acts on the bridge 7. At the same time, some of the plurality of elastic pieces 13 in contact with the bead body 56 immediately rise from the inclined state. By the partial elastic pieces 13A, the tamper evidence band 4 is locally deformed while being eccentric as described above. That is, a part of the tamper evidence band 4 is expanded toward the outer side G as shown in FIG.

  The shear force S acts on the bridge 7 by the tamper evidence band 4 being expanded outward G. That is, the bridge 7 is subjected to the tensile force H due to the locking of the locking portion 8 and the shearing force S due to a part of the elastic pieces 13A. Particularly, when the opening operation is started, some elastic pieces 13 </ b> A rise immediately and the shearing force S acts on the bridge 7 at an early stage. Further, when the opening operation proceeds, some of the elastic pieces 13A are substantially upright, and the tamper evidence band 4 is further expanded toward the outer side G (see FIG. 8).

  The portion where the tamper evidence band 4 is expanded is the edge portion 4f on the bridge 7 side in the tamper evidence band 4 where a part of the elastic piece 13A is provided. The edge 4f of the tamper evidence band 4 is more easily bent than the cap main body 15 and the main body portion 4h of the tamper evidence band 4, and is therefore largely bent by some of the elastic pieces 13A. Moreover, since the edge 4 f of the tamper evidence band 4 is in the vicinity of the bridge 7, the shearing force S can be applied to the bridge 7 to the maximum extent. In this way, the bridge 7 is greatly pulled in the tensile direction and the shearing direction, becomes gradually thinner, and breaks. Thereby, the cap main body 15 which consists of the top plate 2 and the side wall part 3 is isolate | separated from the tamper evidence 4, and a plug opening operation is completed.

  As described above, the tensile force H and the shearing force S act simultaneously on the bridge 7 by performing the opening operation. In particular, the shearing force S acts on the bridge 7 at an early stage when the opening operation starts. Thereby, the bridge 7 can be reliably broken at the stage where the rotation angle of the cap 1 is small. The circumferential position where the tamper evidence band 4 is expanded is not limited to the circumferential position as shown in FIG. 6. For example, the tamper evidence band 4 may be expanded around a plurality of circumferential positions. is there.

  The length t of the elastic piece 13 should just be the length which always contacts the outer peripheral surface of a container opening part, and 2.0-5.0 mm is preferable. If the length t of the elastic piece 13 is 2.0 mm or less, the amount that the tamper evidence band 4 is expanded is small, and if the length t is 5.0 mm or more, the elastic piece 13 is difficult to be guided to the outer peripheral surface 56 b of the bead body 56. Because. The number of the elastic pieces 13 may be one as long as the tamper evidence band 4 can be sufficiently expanded, and more elastic pieces 13 may be provided than in the present embodiment. The angle θ at which the elastic piece 13 is erected may be an angle that can be bent by the opening operation, and is preferably 45 ° or more. This is because when the angle θ is 45 ° or less, it is difficult to be guided to the outer peripheral surface 56b of the bead body 56.

  The circumferential positions where the plurality of elastic pieces 13 are provided are equally spaced along the circumferential direction in the present embodiment, but may be provided with irregular intervals in the circumferential direction. Alternatively, it may be provided so as to be divided in the circumferential direction. The vertical position at which the elastic piece 13 is provided is not limited, but a position corresponding to the bead portion 54 of the container mouth portion 51 is preferable as in this embodiment. If the elastic piece 13 is provided at a position corresponding to the bead portion 54, the elastic piece 13 is elastically bent near the bridge 7 and in a relatively narrow space between the tamper evidence band 4 and the bead body 56. A larger shearing force S can be applied to the bridge 7.

  The shape of the elastic piece 13 is an elongated sectional square shape in the present embodiment, but may be an elongated sectional circular shape, a sectional triangular shape, or a wide plate shape. The strength of the elastic piece 13 is determined depending on the resin, shape, dimensions, and the like constituting the state, but is substantially upright with respect to the inner peripheral surface 4b of the tamper evidence band 4 when the plug opening operation is performed as in this embodiment. It is preferable to have a strength capable of rising up to the point. Since the elastic piece 13 has such a strength, the elastic piece 13 rises up to a substantially upright state with respect to the inner peripheral surface 4b, so that the tamper evidence band 4 can be greatly expanded outward G. . Thereby, a larger shearing force S can be applied to the bridge 7. As described above, the length, the number, the angle, the position, and the shape of the elastic piece 13 are not limited, and any configuration can be used as long as the shearing force S can be applied to the bridge 7. Also good.

  According to the cap 1 of the present embodiment, the bridge 7 can be reliably broken at the stage where the rotation angle of the cap 1 is small by performing the opening operation. That is, even with a small opening operation, the bridge 7 is reliably broken, and the tamper evidence band 4 can be reliably separated from the cap body 15. Accordingly, a user who has purchased a plastic bottle beverage or the like can obtain a feeling that the cap body 15 including the top plate 2 and the side wall portion 3 is removed as soon as the cap 1 is turned.

  The cap of the present embodiment disclosed above shows an example of the cap according to the present invention, and the shape, dimensions, constituent resin, molding method, and the like of each part are appropriately changed. The container to which the cap of the present invention is applied is not limited, and the shape of the container mouth is not limited. The container mouth may be provided with a shape that can guide the tip of the elastic piece so that the elastic piece can be easily bent along with the opening operation. For example, forming the recessed part which inserts the front-end | tip part of an elastic piece in a container mouth part, forming the convex part which hooks the front-end | tip part of an elastic piece, etc. are mentioned. Further, in the present embodiment, the plurality of elastic pieces are integrally formed with the cap. However, a ring-shaped member formed with the plurality of elastic pieces may be retrofitted so as to be fitted into the inner periphery of the cap. The scope of the present invention is indicated by the scope of claims, and includes meanings equivalent to the scope of claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Cap 3 Side wall part 3a Inner peripheral surface 4 Tamper evidence band 4b Inner peripheral surface 4c Edge part (inner peripheral surface)
4f Edge 4h Body part 7 Bridge 8 Locking part 12 Diameter expansion mechanism 13 Elastic piece 13A Partial elastic piece 13a Tip side part 15 Cap body 51 Container port part 54 Bead part 56 Bead body 56a Outer peripheral face 57 Reduced diameter part H Tensile force S Shear force G Outside

Claims (6)

A top plate, and a cap main body formed of a side wall portion formed on the inner peripheral surface of a cap screw portion that extends from the outer peripheral edge of the top plate to one side in the axial direction and is screwed into the container screw portion of the container mouth portion; A tamper-evidence band which is connected to the edge of the cap body via a breakable bridge and has a locking portion for locking to the bead portion of the container mouth portion on the inside thereof,
By the opening operation from the state in which the container is attached to the container mouth portion, the locking portion is locked to the bead portion, whereby a tensile force is applied to the bridge to break the bridge, and the cap body And the tamper evidence band are separated from each other,
The tamper evidence band is provided with a diameter expansion mechanism that applies a shearing force to the bridge by expanding the vicinity of the bridge in the tamper evidence band outward in accordance with the opening operation. Characteristic cap. The diameter expansion mechanism includes an elastic bendable elastic piece erected inwardly at an end portion on the bridge side on an inner peripheral surface of the tamper evidence band,
2. The cap according to claim 1, wherein the elastic piece is configured to contact the outer peripheral surface of the container mouth and bend elastically to apply the shearing force. The elastic piece has a length that always contacts the outer peripheral surface of the container mouth,
It is tilted so as not to resist the outer peripheral surface of the container mouth when the closing operation is performed, and is erected so as to rise up against the outer peripheral surface of the container mouth when the opening operation is performed. The cap according to claim 2.   The said elastic piece has the intensity | strength which can be stood | started up until it reaches the state which stood substantially with respect to the internal peripheral surface of the said tamper evidence band, when opening operation is performed. Cap.   The said elastic piece is standingly arranged in the position corresponding to the bead part of a container opening part, The cap in any one of Claims 2-4 characterized by the above-mentioned.   The elastic piece is formed in an elongated cross-sectional square shape, and a plurality of elastic pieces are provided at predetermined intervals in the circumferential direction on the inner peripheral surface of the tamper evidence band. The described cap.

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