JP2010195455A - Plastic cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plastic cap that is reduced in weight by decreasing the thickness of the skirt wall of a cap body, and is easily separated from a mold without causing a trouble such as buckling during molding. <P>SOLUTION: The plastic cap is screwed to the mouth of a container so as to be liquid-tight, and formed of a circular top wall and a skirt wall extending downward from the circular edge of the top wall. The skirt wall includes a main portion in a high position and a tamper evident band in a low position. The internal circumferential surface of the tamper evident band includes a plurality of locking pieces formed circumferentially at predetermined intervals, the locking pieces used for locking a jaw from below which is lower than the male thread of the mouth. The internal circumferential surface also has a step whose upper portion and lower portion are a small-diameter portion and a large-diameter portion, respectively. The large-diameter portion has a projection extending from the step to the lower end of the large-diameter portion between the locking pieces. The locking pieces are prevented from coming into contact with the lower end of the small-diameter portion when displaced outwardly. Accordingly, even if the main portion is formed thin, satisfactory reinforcement and power transmission are secured by the projection. This solves the above problem. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a plastic cap having a tamper-evidence mechanism that is screwed and sealed to the mouth of a container filled with a liquid material, and more specifically, when the wall thickness of the skirt wall of the cap body is reduced. Even so, the plastic incorporates a structure that allows the plastic cap to be released smoothly without buckling of the tamper-evident band due to the protruding force of the stripper used to release the mold from the mold when molding the plastic cap. Regarding the cap.

  As shown in FIG. 8, a conventional plastic cap with a tamper-evident mechanism comprises a circular top wall (not shown) and a skirt wall 50 that hangs down from the periphery of the top wall. The skirt wall 50 includes a main portion 52 above the peripheral break portion 51 and a tamper evidence band 53 below the peripheral break portion 51. A female thread that engages with a male thread formed on the outer peripheral surface of the mouth portion is formed, and further, on the inner peripheral surface of the tamper evidence band 53, the male thread is located below the male thread of the container mouth portion. A plurality of locking pieces 54 to be locked from below are provided on the formed jaw portion at predetermined intervals in the circumferential direction (see, for example, Patent Document 1).

However, in contrast to the conventional example of FIG. 8, as shown in FIG. 9, the main portion 52 of the skirt wall 50 is made thin in order to reduce the weight for the purpose of saving resources of the synthetic resin that is the raw material of the plastic cap. It has been tried. When the main portion 52 is made thinner in this way, the outer diameter R1 of the main portion 52 of the plastic cap approaches the inner diameter R2 of the lower portion of the tamper evident band 53 and finally becomes smaller than the lower inner diameter R2. In particular, the inner peripheral surface of the lower portion of the tamper evident band 53 is provided with a lightening portion for receiving the locking piece 54 when the cap is attached to the container mouth portion. The inner diameter of the lower part is formed large.
In other words, the outer diameter R1 of the main portion 52 and the lower inner diameter R2 of the tamper evidence band 53 have little or no overlap in the direction of the axis A of the plastic cap.

JP 2007-191206 A

The thin plastic cap described in Patent Document 1 described above has little overlap in the axis A direction between the outer diameter R1 of the main portion 52 and the lower inner diameter R2 of the tamper evidence band 53. The lower surface 53a of the band 53 protrudes and is released from the mold 55 (see FIG. 10), but at this time, the protruding force P is not easily transmitted to the main portion 52. That is, since there is actually no overlap in the axis A direction between the lower surface 53a of the tamper evidence band 53 that applies the protruding force P and the main portion 52, the protruding force P is transferred from the tamper evidence band 53 to the main portion 52. However, there is a possibility that the tamper evident band 53 will buckle and the plastic cap may not be released from the mold 55 smoothly. On the other hand, it is not thin.

  Accordingly, an object of the present invention is to provide a plastic cap that can be easily released from a mold without causing troubles such as buckling of a tamper-evident band, while reducing the thickness of the main part of the cap body skirt wall and reducing the weight. Is to provide.

The present invention has been proposed in order to achieve the above object, and has the following configuration.
That is, according to the present invention, it comprises a circular top wall and a skirt wall depending from the periphery of the top wall, and the skirt wall has a circumferential fracture portion below, and the skirt wall is above the circumferential fracture portion. And a lower tamper-evident band, and a female thread that is threadedly engaged with a male thread formed on the outer peripheral surface of the container mouth is formed on the inner peripheral surface of the main part. A plurality of locking pieces are provided on the inner peripheral surface of the tamper-evidence band at intervals in the circumferential direction to lock the jaws formed below the male thread of the container mouth from below. In the plastic cap, the tamper evidence band has a step portion on an inner peripheral surface, and the tamper evidence band is composed of a small diameter portion above the step portion and a large diameter portion below. The diameter portion has a protrusion extending from the step portion to the lower end of the large diameter portion. The protrusion is formed at a position corresponding to the interval between the locking pieces, and the locking piece does not contact the lower end of the small diameter portion when displaced outward. A plastic cap is provided.

  Further, according to the present invention, there is provided a plastic cap in which the inner surface of the protrusion is an inclined surface that gradually increases in diameter from the upper end to the lower end.

In addition, according to the present invention, it comprises a circular top wall and a skirt wall depending from the periphery of the top wall,
The skirt wall has a circumferentially broken portion below, and the skirt wall is composed of a main portion above the circumferentially broken portion and a lower tamper-evident band. A female thread to be engaged with a male thread formed on the outer peripheral surface of the mouth is formed, and formed on the inner peripheral surface of the tamper evidence band below the male thread of the container mouth. In the plastic cap provided with a plurality of locking pieces that are spaced from each other in the circumferential direction to be locked to the jaw portion from below,
The tamper evident band has a step portion on an inner peripheral surface, and the tamper evidence band is composed of a small diameter portion above the step portion and a large diameter portion below, and the step portion is directed downward. An annular reinforcing portion having an annular inclined surface having a gradually increasing diameter is formed, and the locking piece does not contact the lower end of the small diameter portion when displaced outwardly. Is done.

The operation of the first problem solving means is as follows.
That is, when the plastic cap is released from the mold, if the lower surface of the large-diameter portion of the tamper-evidence band protrudes, the protruding force is mainly applied to the upper main portion by the protrusion corresponding to the position between the locking pieces. The tamper-evidence band is reinforced by the protrusion that extends from the step portion to the lower end of the large-diameter portion, and the plastic cap is released from the mold without buckling. Further, since the locking piece is displaced outward without contacting the lower end of the small diameter portion, it can be smoothly screwed to the container mouth portion.

  Further, the second problem solving means has an effect that the protrusion has an inclined surface whose inner surface gradually increases in diameter from the upper end toward the lower end, so that the protruding amount and tamper shrimp are reduced even though the amount of resin is reduced. The force that reinforces the large diameter part of the dent band remains the same.

  Moreover, even if the annular reinforcing portion having an annular inclined surface having a gradually increasing diameter is formed on the stepped portion in the stepped portion, the operation by the third problem solving means is the same as the action by the first problem solving means. The protruding force is transmitted to the upper main part by the annular reinforcement, and the tamper-evident band is reinforced by this annular reinforcement, and the plastic cap is released from the mold without buckling and locked. The piece can be displaced outward without coming into contact with the lower end of the small diameter portion, and the plastic cap can be smoothly screwed into the container mouth.

  Although the plastic cap of the present invention achieves weight reduction by thinning the skirt portion of the cap body, it can be easily separated from the mold without causing problems such as buckling of the tamper-evidence band during molding. There is an effect that the mold can be formed, and further, the locking piece is displaced outward without contacting the lower end of the small diameter portion and can be easily screwed to the container mouth portion.

  Further, in addition to the above effects, the plastic cap of the present invention has the effect that the protruding force and the force that reinforces the large diameter portion of the tamper evident band are not changed, although the amount of protrusion resin can be reduced.

  The plastic cap of the present invention can achieve the same effect as described above even when an annular reinforcing portion having an annular inclined surface is formed in the stepped portion.

It is a half cut longitudinal cross-sectional view of the state which screwed the plastic cap which shows embodiment shown in Example 1 of this invention to the container opening part. It is a half-cut longitudinal cross-sectional view of the plastic cap of FIG. It is a bottom view of the plastic cap of FIG. It is principal part sectional drawing of the plastic cap of FIG. It is principal part sectional drawing which shows the mold release state from the metal mold | die of the plastic cap of FIG. It is a half-cut longitudinal cross-sectional view of the plastic cap which shows other embodiment shown in Example 2 of this invention. It is principal part sectional drawing of the plastic cap of FIG. It is sectional drawing which shows a prior art example. It is sectional drawing of the state which made the conventional example thin. It is sectional drawing which shows the mold release state from the metal mold | die of the conventional example of the state made thin.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  In the drawing, a plastic cap 1 is screwed into a mouth 3 of a container 2 in a liquid-tight manner, and is composed of a circular top wall 4 and a skirt wall 5 depending from the periphery of the top wall 4. The skirt wall 5 is composed of a main portion 7 above the circumferential rupture portion 6 and a tamper-evidence band 8 below, which is slightly below the middle portion. On the inner peripheral surface, a female thread 10 is formed which is engaged with the male thread 9 formed on the outer peripheral surface of the container mouth portion 3, while on the inner peripheral surface of the tamper evidence band 8, A plurality of locking pieces 12 are provided at predetermined intervals in the circumferential direction to be locked to the jaw portion 11 formed below the male thread 9 of the container mouth portion 3 from below.

  The tamper evident band 8 has a step portion 13 on the inner peripheral surface, and the tamper evidence band 8 includes a small diameter portion 14 above the step portion 13 and a large diameter portion 15 below. The diameter portion 15 is formed with a protrusion 16 extending from the step portion 13 to the lower end of the large diameter portion 15, and this protrusion 16 is formed at a position corresponding to between the locking pieces 12. This locking piece 12 is configured not to come into contact with the lower end 14a of the small diameter portion 14 when displaced outward.

  The container 2 may have any shape as long as it can be filled with a liquid material such as a milk beverage, coffee beverage, fruit juice beverage, and the plastic cap 1 of the present invention can be screwed into the mouth 3 of the container 2 in a liquid-tight manner. There is no particular limitation on the type of plastic.

  The circular top surface wall 4 is concentrically provided on its lower surface with an inner ring 20 that seals the inner peripheral surface of the mouth portion 3 of the container 2 and an outer ring 21 that contacts and seals the outer peripheral end surface of the mouth portion 3 on the outer side. Thus, the liquid tightness of the container 2 is made perfect.

  As described above, the skirt wall 5 is divided into an upper main part 7 and a lower tamper-evidence band 8 with the circumferential fracture part 6 as a boundary. A female thread 10 corresponding to the male thread 9 engraved on the outer peripheral surface is formed so as to be able to be screwed into the container mouth 3 and the main part 7 after being opened is detachable. In order to assist wearing and unscrewing, a slip stopper 22 is provided on the outer peripheral surface of the main portion 7.

On the other hand, as described above, the tamper evident band 8 has a step portion 13 on its inner peripheral surface, and is composed of a small diameter portion 14 above the step portion 13 and a large diameter portion 15 below. A plurality of locking pieces 12 are provided at substantially equal intervals in the lower part of the inner peripheral surface of the diameter portion 15. These locking pieces 12 exist in an inclined state inward and upward, and most of the locking pieces 12 can be accommodated in the large-diameter portion 15. Further, when the locking piece 12 is displaced outward, that is, when it is displaced in a direction to be accommodated in the large diameter portion 15, it does not contact the lower end 14 a of the small diameter portion 14. This is so that the plastic cap 1 can be smoothly screwed onto the container opening 3.

  Further, as described above, the protrusion 16 extending from the step portion 13 to the lower end of the large diameter portion 15 is formed in the corresponding position between the locking pieces 12 on the large diameter portion 15 of the tamper evident band 8. Yes. The inner surface of the protrusion 16 is an inclined surface 23 that gradually increases in diameter from the upper end toward the lower end. The presence of the protrusions 16 reinforces the tamper evidence band 8 itself. Furthermore, when the plastic cap 1 is released from the mold, the lower surface 15a of the large-diameter portion 15 of the tamper-evidence band 8 is protruded. It is transmitted smoothly. Accordingly, since the concentration of stress on the tamper evident band 8 is greatly reduced, the plastic cap 1 can be easily released from the mold without the tamper evidence band 8 buckling.

  In the skirt wall 5 of the plastic cap 1, the upper main portion 7 and the lower tamper evidence band 8 are separated by the circumferential fracture portion 6 and connected by the circumferential fracture portion 6. In this embodiment, the circumferential fracture portion 6 is provided with a plurality of breakable bridges 24 at intervals in the circumferential direction. Further, pedestal portions 25 and 26 are provided on the upper surface of the tamper evident band 8 and the lower surface of the main portion 7. When a load exceeding the allowable range of the circumferential fracture portion 6 is applied in the axial direction of the plastic cap 1, the pedestal portions 25 and 26 support the load by the pedestal portions 25 and 26, and the circumferential fracture portion 6. It plays a role not to buckle or break.

  That is, breaking the circumferential fracture portion 6 means breaking the bridge 24, and for the first time, the main portion 7 and the tamper evidence band 8 are separated, and the plastic cap 1 is opened. Then, the separated tamper evidence band 8 falls and remains on the flange portion 27 (see FIG. 1) of the mouth portion 3 of the container 2, and it is understood whether or not the tamper evident band 8 has been tampered with.

Next, the use situation of the plastic cap 1 having the above configuration will be described with reference to the drawings.
The plastic cap 1 has a skirt wall 5 suspended from the peripheral edge of the circular top wall 4 and is screwed in a liquid-tight manner to the mouth 3 of the container 2 (see FIG. 1). First, in order to release the plastic cap 1 from the mold 28, a protruding force P is applied to the lower surface 15a of the large diameter portion 15 of the tamper evident band 8 (see FIG. 5). This protrusion force P is smoothly transmitted to the upper main portion 7 due to the presence of the protrusion 16, and stress is not concentrated on the tamper evidence band 8. Further, the tamper evidence band 8 is seated by the reinforcing force of the protrusion 16. The plastic cap 1 can be smoothly released from the mold 28 without bending.

  The plastic cap 1 released from the mold 28 is in a state in which the locking piece 12 hangs downward, so that it is bent in the state shown in FIG. 2 so as to be inclined inward and upward. Next, the plastic cap 1 in the state shown in FIG. 2 is applied to the mouth 3 of the container 2 filled with the liquid material and screwed. At this time, even if a load exceeding the allowable range is applied in the axial direction of the plastic cap 1, the load is supported by the pedestal portions 25 and 26 to protect the circumferential fracture portion 6 from buckling and fracture.

  In order to consume the liquid in the container 2, fingers are put on the main part 7 above the skirt wall 5 of the plastic cap 1 and rotated in the opening direction, and a plurality of locking pieces 12 are engaged with the jaw part 11 of the container 2. The bridge 24 of the circumferentially broken portion 6 is broken, the main portion 7 and the tamper evident band 8 are separated, the main portion 7 is removed from the mouth portion 3 of the container 2, and the plastic cap 1 is opened. To do. Therefore, once the plastic cap 1 is opened, the tamper evidence band 8 separated from the main portion 7 falls on the collar portion 27 of the mouth portion 3 of the container 2 and remains, and whether or not the tamper evident opening has been made. Recognize. If the liquid material remains in the container 2 and is to be temporarily stored, the main part 7 is applied to the mouth 3 of the container 2 and rotated and screwed in the closing direction with fingers.

  FIGS. 6 and 7 show another embodiment of the present invention. The difference between this plastic cap 1a and that shown in FIGS. The point is that an annular reinforcing portion 31 having an annular inclined surface 30 that gradually becomes larger in diameter is formed. That is, also with the annular reinforcing portion 31, as in the case of the plastic cap 1 of FIGS. 1 to 5, the protruding force is smoothly transmitted to the upper main portion 7 by the annular reinforcing portion 31, and the annular reinforcing portion 31. Thus, the tamper evident band 8 itself can be reinforced, and the plastic cap 1a can be released from the mold 28 without buckling. Further, the locking piece 12 is connected to the lower end 14a of the small diameter portion 14 and The plastic cap 1a can be smoothly displaced outward without contacting, and the plastic cap 1a can be screwed onto the container mouth portion 3. Since other configurations and operations are the same as those shown in FIGS. 1 to 5, reference numerals are attached to the drawings and description thereof is omitted.

  As mentioned above, although Example 1 and 2 of this invention were demonstrated, it should be understood that a concrete structure is not limited to this and the change in the range which does not deviate from the summary of this invention is possible suitably. .

  Although the plastic cap of the present invention has realized weight reduction, it seems that normalization of insufficient strength and force transmission, and easy release from the mold without causing problems such as buckling of the tamper evident band In such cases, there is a high availability.

DESCRIPTION OF SYMBOLS 1, 1a Plastic cap 2 Container 3 Mouth part 4 Circular top wall 5, 50 Skirt wall 6, 51 Circumferential fracture part 7, 52 Main part 8, 53 Tamper evidence band 9 Male thread 10 Female thread 11 Jaw part 12 , 54 Locking piece 13 Stepped portion 14 Small diameter portion 14a Lower end 15 Large diameter portion 15a, 53a Lower surface 16 Projection 20 Inner ring 21 Outer ring 22 Sliding stop 23 Inclined surface 24 Bridge 25, 26 Pedestal portion 27 Gutter portion 28, 55 Mold 30 Annular inclined surface 31 Annular reinforcement A Axis R1 Outer diameter R2 Lower inner diameter

Claims (3)

It consists of a circular top wall and a skirt wall that hangs from the periphery of the top wall,
The skirt wall has a circumferential fracture portion below, the skirt wall is composed of a main portion above the circumferential fracture portion, and a lower tamper evidence band,
On the inner peripheral surface of the main portion, a female thread that is screwed with a male thread formed on the outer peripheral surface of the container mouth is formed.
On the inner peripheral surface of the tamper-evident band, a plurality of locking pieces are provided at intervals in the circumferential direction to be locked from below to a jaw portion formed below the male thread of the container mouth portion. Plastic caps
The tamper evidence band has a step portion on the inner peripheral surface, and the tamper evidence band is composed of a small diameter portion above the step portion and a large diameter portion below.
The large diameter portion is formed with a protrusion extending from the step portion to the lower end of the large diameter portion,
The projection is formed at a position corresponding to the locking piece,
The plastic cap, wherein the locking piece does not contact the lower end of the small diameter portion when displaced outward.   2. The plastic cap according to claim 1, wherein an inner surface of the projection is an inclined surface having a gradually increasing diameter from the upper end toward the lower end. It consists of a circular top wall and a skirt wall that hangs from the periphery of the top wall,
The skirt wall has a circumferential fracture portion below, the skirt wall is composed of a main portion above the circumferential fracture portion, and a lower tamper evidence band,
On the inner peripheral surface of the main portion, a female thread that is screwed with a male thread formed on the outer peripheral surface of the container mouth is formed.
On the inner peripheral surface of the tamper-evident band, a plurality of locking pieces are provided at intervals in the circumferential direction to be locked from below to a jaw portion formed below the male thread of the container mouth portion. Plastic caps
The tamper evidence band has a step portion on the inner peripheral surface, and the tamper evidence band is composed of a small diameter portion above the step portion and a large diameter portion below.
The stepped portion is formed with an annular reinforcing portion having an annular inclined surface that gradually becomes larger in diameter downward.
The plastic cap, wherein the locking piece does not contact the lower end of the small diameter portion when displaced outward.

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