JP5934613B2 - Resin cap - Google Patents

Description

  The present invention relates to a resin cap that is attached to seal a resin bottle or the like for beverages.

  As a resin cap attached to a resin bottle for beverages, one having a tamper evidence performance capable of confirming the presence or absence of unauthorized opening is widely used. For example, a tamper evident opening provided with a top plate and a cap body composed of a side wall extending from an edge of the top plate, and a tamper evidence band connected to the open end of the cap body via a plurality of breakable bridges. What can confirm the presence or absence is known.

  In the cap made of resin, the locking part is locked to the bulging part of the mouth of the bottle by the opening operation from the mounted state, and the plurality of bridges are broken by a tensile force acting on the plurality of bridges. The cap body and the tamper evidence band are separated from each other. Therefore, when it is confirmed that the bridge is broken, it is recognized that the bridge is opened. If the consumer before purchase can recognize that the bottle has been opened, damage caused by mischief can be prevented and the quality of the contents can be guaranteed.

  In general, the resin cap is molded using an injection molding method or a compression molding method. In any molding method, after the molten resin is poured into the mold and cooled, the molded product is die-cut. The thread provided on the inner peripheral surface of the side wall of the resin cap protrudes from the inner peripheral surface, and serves as an undercut portion when the molded product is removed from the mold. For this reason, in order to take out the molded product from the mold, it is discharged from the tamper evidence band side of the molded product and the thread that is the undercut portion is forcibly removed.

  For example, in a molded product having a thread of 1.5 laps, there are two crest regions having two crests and one crest region in the axial direction. In this case, the balance of the release resistance in the circumferential direction when forcibly removing is lost, the molded product is inclined toward the two mountain regions where the release resistance is large, and buckling deformation easily occurs on the region side. Further, when forcibly removing the screw, the thread pushes the side wall radially outward, but the force applied to the thread at that time is distributed to two threads in the two-thread region, and one screw thread in the one-thread region. Concentrate on. Therefore, one screw thread in one thread region is easily deformed. Further, since the axial direction width on which the force is applied to the side wall is narrower in the single mountain region than in the two mountain region, the side wall of the single mountain region is suddenly pushed out. When the side wall of one mountain region is suddenly pushed and deformed, whitening is likely to occur in that portion.

  In order to suppress molding defects such as whitening of the side walls and deformation of the threads, it is necessary to adjust the production cycle to an appropriate speed and cool it slowly, but productivity is lowered. For example, Patent Document 1 discloses that the start end of a long thread completely belongs to a single strip region by eliminating the threaded end located above the start of the long thread where no gas vent groove is formed. A resin cap is described in which the resistance of this portion is reduced, and the force received by the cap through the screw thread is uniformly distributed over the entire circumference during die cutting (see FIG. 2 of the same document). ).

Japanese Patent Laid-Open No. 8-34455

  In the resin cap of Patent Document 1, although the start end portion of the long screw thread belongs to the single strip region completely and the resistance of this portion is reduced, the axial direction on which the force on the side wall is applied when forced The width is greatly different between the single region and the two regions in the circumferential direction. If the axial width to which force is applied is greatly different in the circumferential direction, when the production cycle is accelerated, whitening of the side walls and deformation of the threads occur, and molding defects cannot be suppressed.

  In view of the above-described problems of the prior art, the present invention has an object to provide a resin cap that is less likely to cause whitening of the side wall and deformation of the screw thread, suppress molding defects, speed up the production cycle, and reduce costs. And

In order to achieve the above object, the following technical measures were taken.
That is, the present invention provides a resin cap having a top plate and a cylindrical side wall extending from the outer edge of the top plate, and provided with a screw thread that circulates around the inner peripheral surface of the side wall. It is characterized by being formed with the same number of peaks in the axial direction over the entire circumference.

  According to the present invention, the threads that circulate around the inner peripheral surface of the side wall are formed with the same number of threads in the axial direction over the entire circumference of the side wall. Unlike the case where both of the two mountain areas exist, only the same mountain area exists around the entire circumference. Therefore, when forcibly removing, the axial width on which the force is applied on the side wall becomes substantially uniform over the entire circumference. Thereby, even if it is a case where a production cycle is accelerated, it is hard to produce the whitening of a side wall and a deformation | transformation of a screw thread, and it can suppress a molding defect.

A plurality of thread grooves in which a plurality of through-grooves communicating in the axial direction are regularly formed in the circumferential direction in the thread and the thread exists in the circumferential direction on the inner circumferential surface of the side wall, and the thread is a plurality of groove region there is no that are formed on the regularly alternate. During non-physical disconnect, the axial width consuming forces in the side wall, can be made substantially uniform over the entire circumference.

The screw thread is formed to have a length that makes two rounds on the inner peripheral surface of the side wall, and an upper screw thread that forms a one-turn area on the top plate side and a lower screw thread that forms a one-turn area on the side wall edge side. Each screw region length of the upper screw thread is shorter than each screw region length of the lower screw thread, and each screw region of the upper screw thread in the axial direction of the lower screw thread that exist in the circumferential direction range of each threaded region.

Since each screw region of the upper screw thread exists in the circumferential range of each screw region of the lower screw thread in the axial direction, the axial width on which the force on the side wall is applied is substantially uniform over the entire circumference. In addition, the length of each screw region of the upper screw thread is shorter than the length of each screw region of the lower screw thread, and the weight can be reduced.

  The above-mentioned resin cap can be applied to any type of cap. For example, a cap body is constituted by the top plate and the side wall, and a plurality of bridges that can be broken at the open end of the cap body are provided. It is preferable that a tamper evidence band connected to each other is provided.

  As described above, according to the present invention, when the force is removed, the axial width on which the force is applied on the side wall is substantially uniform over the entire circumference, so that the side wall is whitened and the thread is deformed. It becomes difficult and molding defects are suppressed, the production cycle can be accelerated, and the cost can be reduced.

It is the perspective view which looked at the resin-made caps which concern on 1st Embodiment of this invention from the back side. It is sectional drawing of the resin-made caps of FIG. It is an expanded view showing the screw thread of the resin caps of FIG. It is an expanded view showing the screw thread of the resin-made caps concerning 2nd Embodiment of this invention. It is an expanded view showing the screw thread of the resin-made caps concerning 3rd Embodiment of this invention. It is sectional drawing of the resin caps which concern on 4th Embodiment of this invention. It is an expanded view showing the screw thread of the resin caps of FIG. It is an expanded view showing the screw thread of the resin-made caps concerning 5th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a resin cap 1 according to the first embodiment of the present invention as seen from the back side, and FIG. 2 is a cross-sectional view of the resin cap 1. In the following description, the side corresponding to the upper side in the axial direction of the resin cap 1 in FIG. 2 is simply referred to as the upper side, and the side corresponding to the lower side in the axial direction is simply referred to as the lower side. The resin cap 1 is used by being attached to a mouth of a resin bottle for beverages, and is integrally formed of polypropylene by compression molding or injection molding, and the cap body 2 located at the upper part. And a tamper evidence band 3 connected to the lower end of the cap body 2. The material for forming the resin cap 1 is not particularly limited, and polyethylene, polylactic acid, and the like are suitably used in addition to the polypropylene used in the present embodiment.

  A mouth portion (not shown) to which the resin cap 1 is attached has a cylindrical main body portion formed to have substantially the same diameter from the upper end to the lower end, a male screw formed on the outer peripheral side of the main body portion, a bulging portion, and a support ring. Etc. The cap body 2 is composed of a top plate 4 positioned at the top and a side wall 5 extending downward from the outer edge 4a of the top plate 4, and the top plate 4 is in a disk shape having a required dimension. A packing (not shown) for sealing the container is provided inside the top plate 4. The sealing structure for sealing the container may be any type, for example, a one-piece type with a middle leg, an annular rib, an outer leg, and the like integrally formed on the inner surface of the top plate. .

  The side wall 5 is formed in a cylindrical shape, and an internal thread portion 14 is formed on the inner peripheral surface 5a thereof. A knurling 9 extending in the axial direction is provided on the outer peripheral surface 5 b of the side wall 5. A plurality of bridges 10 are provided at predetermined intervals along the circumferential direction at the boundary between the side wall 5 and the tamper evidence band 3. The plurality of bridges 10 connecting the cap body 2 and the tamper evidence band 3 to each other are designed to break when pulled by a predetermined force. A locking portion 11 is provided inside the tamper evidence band 3. The locking portion 11 is folded back obliquely inward from the lower end portion 3a of the tamper evidence band 3 and is intermittently formed along the circumferential direction. The locking portion 11 can be elastically deformed inward, outward and downward, and is positioned directly below the bulging portion while being attached to the mouth portion. Locked. In addition, the form of a bridge | bridging or a latching | locking part is not limited, For example, you may form the latching | locking part continuously along the circumferential direction.

  When the mounted resin cap 1 starts to be turned in the opening direction, the locking portion 11 is locked to the bulging portion of the mouth, and tensile force starts to act on the plurality of bridges 10. When the resin cap 1 is further rotated, the plurality of bridges 10 are greatly pulled and gradually become thin, leading to breakage. Thereby, the cap main body 2 which consists of the top plate 4 and the side wall 5 is isolate | separated from the tamper evidence band 3, and the resin bottle is opened.

  FIG. 3 is a development view of the screw thread 12 of the resin cap 1. The female screw portion 14 formed on the inner peripheral surface 5a of the side wall 5 includes a screw thread 12 having a substantially trapezoidal cross section around the inner peripheral surface 5a. The screw thread is not limited to a trapezoidal cross section, and may have another shape such as a curved cross section. As shown in FIGS. 2 and 3, the screw thread 12 circulates the inner circumferential surface 5 a of the cylindrical side wall 5 twice from the start end 12 a at the start of cutting to the end 12 b at the end of cutting. Therefore, the turning angle around the midpoint of the side wall of the screw thread 12 is 720 °. As shown in FIG. 2, the axial positions of the start end 12a and the end end 12b of the thread 12 are substantially the same. The screw threads 12 are formed with the same number of threads in the axial direction over the entire circumference of the side wall 5, and there are no regions with different numbers of threads in the axial direction on the inner peripheral surface 5 a of the side wall 5.

  When the resin cap 1 is molded, the molten resin is injected into the molding die, and then cooled to a predetermined temperature, and the molded product is die-cut. Since the thread 12 taken at the position of the inner peripheral surface 5a of the side wall 5 of the resin cap 1 is an undercut portion when the molded product is punched, the thread 12 is removed when forcibly removing it. With the resistance of 12, the side wall 5 is expanded outward in the radial direction and deformed.

  In the resin cap 1 of the present embodiment, as described above, the threads 12 are formed with the same number of threads in the axial direction over the entire circumference of the side wall 5, and differ in the axial direction on the inner peripheral surface 5 a of the side wall 5. There is no mountain area. Therefore, the axial width D (see FIG. 3) to which a force is applied on the side wall 5 is substantially uniform over the entire circumference when forced.

  According to the resin cap 1 of the present embodiment, the thread 12 that circulates the inner peripheral surface 5a of the side wall 5 is formed with the same number of threads in the axial direction over the entire circumference of the side wall 5. For example, unlike the case where both the one-crest region and the two-crest region exist in the axial direction, only the same crest region exists throughout the entire circumference. Therefore, when forcibly removing, the axial width D to which a force is applied on the side wall 5 becomes substantially uniform over the entire circumference. Therefore, even when the production cycle is accelerated, whitening of the side wall 5 and deformation of the screw thread 12 hardly occur, and molding defects can be suppressed. Thereby, the production cycle of the resin cap 1 can be accelerated, and the cost can be reduced.

  FIG. 4 is a development view showing the thread 21 of the resin cap 20 according to the second embodiment of the present invention. In the screw thread 21 of the present embodiment, a plurality of through grooves 22 communicating in the axial direction are formed at substantially equal intervals along the circumferential direction. The axial positions of the through-grooves 22 </ b> A located on the lower side, which is the first turn, and the through-grooves 22 </ b> B located on the upper side, which is the second turn, coincide with each other. A plurality of screw regions 23 where the screw threads 21 are present in the direction and a plurality of groove regions 24 where the screw threads 21 are not present are regularly and alternately formed. The thread of the present invention formed in the axial direction with the same number of threads over the entire circumference of the side wall 5 refers to the entire continuous thread including a plurality of groove regions 24. .

  In the present embodiment, a plurality of through grooves 22 communicating in the axial direction are formed at substantially equal intervals along the circumferential direction, and screw regions 23 and groove regions 24 are alternately and regularly arranged in the circumferential direction. Due to the arrangement, the presence of the through groove 22 does not change the axial width D to which the force is applied in the side wall 5, and is substantially uniform over the entire circumference.

  Even if the plurality of through-grooves communicating in the axial direction are not formed at substantially equal intervals along the circumferential direction, for example, the plurality of through-grooves communicating in the axial direction are regularly formed along the circumferential direction. If the screw regions and the groove regions are regularly and alternately arranged in the circumferential direction, the axial width on which the force is applied on the side wall 5 does not change and becomes substantially uniform over the entire circumference. As such a case, the thread may be intermittent in length, such as long, short, long, short, long,... In the circumferential direction.

  FIG. 5 is a development view showing the thread 31 of the resin cap 30 according to the third embodiment of the present invention. In the thread 31 of the present embodiment, a plurality of through grooves 32 communicating in the axial direction are formed at substantially equal intervals along the circumferential direction. The axial positions of the through groove 32A located on the lower side, which is the first turn, and the through groove 32B located on the upper side, which is the second turn, coincide with each other. Screw regions 33 where the screw threads 31 are present and groove regions 34 where the screw threads 31 are not present are regularly and alternately formed.

  In the present embodiment, a predetermined length portion from the terminal end to the starting end in the screw thread 31 is a screw width reducing portion 31a that receives resistance as an undercut portion during molding. In the screw width reducing portion 31a, the screw width s1 is reduced to about a half of the screw width s2 of the other portion, and the weight is reduced. That is, if the predetermined length portion from the terminal end to the start end of the screw thread 31 does not contribute to screwing into the mouth portion of the beverage bottle, if the screw width is reduced only by the predetermined length portion, the reduced amount Only the weight is reduced, and the weight can be reduced without affecting the closing form. Even in this case, the axial width D to which the force is applied in the side wall 5 hardly changes, and is substantially uniform over the entire circumference.

  FIG. 6 is a cross-sectional view of a resin cap 40 according to the fourth embodiment of the present invention, and FIG. 7 is a development view showing threads of the resin cap 40. The locking portion 41 of the resin cap 40 of the present embodiment is formed in a bellows shape that is continuous in the circumferential direction, and a plurality of inner protrusions 41a that are folded in a U-shape are configured. Inside the top plate 4, a packing 42 for sealing a container such as a beverage bottle is shown. The packing 42 includes a disc-shaped main body portion 43, an annular side seal portion 44 that bends downward from the outer periphery of the main body portion 43, and a cylindrical middle foot portion 45 that extends downward from the lower surface of the main body portion 43. Have. The side seal portion 44 enters between the mouth portion of the container and the side wall 5, and the middle foot portion 45 is in close contact with the inner surface of the mouth portion. The seal structure by these seals the mouth of the container satisfactorily, so that the airtightness inside the container is maintained high.

  The screw thread 46 in this embodiment is formed in the length which makes two rounds of the inner peripheral surface 5a of the side wall 5 similarly to the said embodiment. As shown in the developed view of FIG. 7, the screw thread 46 is composed of an upper screw thread 47 serving as a one-turn area on the top plate side and a lower screw thread 48 serving as a one-turn area on the side wall edge side. The upper thread 47 and the lower thread 48 are each composed of seven screw regions and seven groove regions. Each screw region length t1 of the upper screw thread 47 is shorter than each screw region length t2 of the lower screw thread 48. In the axial direction, each screw region 47 r of the upper screw thread 47 is present in the circumferential range of each screw region 48 r of the lower screw thread 48. The circumferential centers of the screw regions 47r of the upper screw thread 47 and the screw regions 48r of the lower screw thread 48 coincide.

  The inner peripheral surface 5a of the side wall 5 includes first to seventh areas 49A to 49G from the left side of FIG. 7 so as to correspond to the screw regions 47r and 48r. The circumferential ranges of the sections 49A to 49G are the ranges of the screw regions 47r and 48r and the half groove regions on both sides in the circumferential direction. The first to third sections 49A to 49C and the fifth to seventh sections 49E to 49G are each configured with a rotation angle of 50 °, and only the fourth section 49D is configured with a rotation angle of 60 °.

  The plurality of screw region lengths t1 of the upper thread 47 are the same. The screw region lengths t2 corresponding to the first to third regions 49A to 49C and the fifth and sixth regions 49E and 49F of the lower thread 48 are the same, and the screw region length corresponding to the fourth region 49D. t3 is longer than the other areas. The start of cutting of the screw region 48r corresponding to the seventh area 49G of the lower screw thread 48 is tapered. Each screw region length t1 of the upper thread 47 in the first to third regions 49A to 49C and the fifth and sixth regions 49E and 49F is 60% of each screw region length t2 of the lower thread 48. ing. The screw region length t1 of the upper stage thread 47 in the fourth section 49D and the seventh section 49G is 50% of the thread area length t3 of the lower stage thread 48. Each screw region length t1 of the upper screw thread 47 is preferably 40% to 80%, more preferably 50% to 60% of each screw region length t2, t3 of the lower screw thread 48.

  According to the resin cap 40 of the present embodiment, each screw region 47r of the upper screw thread 47 does not protrude in the circumferential direction from each screw region 48r of the lower screw thread 48 in the axial direction, and each screw of the lower screw thread 48 Since it exists in the circumferential direction range of the region 48r, it is possible to maintain the action of making the axial width D to which the force on the side wall 5 is applied substantially uniform over the entire circumference when forced. Therefore, even when the production cycle is accelerated, the side wall 5 is not easily whitened and the thread is hardly deformed, and molding defects can be suppressed. Thereby, the production cycle of the resin cap 40 can be accelerated, and the cost can be reduced.

  Since each screw region length t1 of the upper screw thread 47 is shorter than each screw region length t2, t3 of the lower screw thread 48, each screw region length of the upper screw thread 47 and each of the lower screw screw 48 The weight can be reduced as compared with the case where the screw region length is the same. Furthermore, since each screw region length t1 of the upper thread 47 is shorter, the contact area with the screw part formed on the inner periphery of the mouth of the container is reduced. When the contact area decreases, the resistance at the time of winding and opening the resin cap 40 around the mouth of the container is reduced, so that it is easy to manufacture and the consumer can open with less force. After mounting the resin cap 40 on the mouth of the container, cleaning water or hot water is sprayed toward the outer surface of the resin cap 40, and the cleaning water or hot water is discharged through the cleaning hole 55 (see FIG. 6) formed in the side wall 5. Hot water is guided to the outer peripheral surface of the mouth of the container. Thereby, the inner surface of the resin cap 40 and the outer peripheral surface of the mouth of the container are cleaned. Since each screw region length t1 of the upper thread 47 is shorter, the flow path of the cleaning water is wider than before, and the cleaning performance of the mouth can be improved.

FIG. 8 is a development view showing the thread 51 of the resin cap 50 according to the fifth embodiment of the present invention. The resin cap 50 of the present embodiment is different from the fourth embodiment of FIG. 7 in that the inner peripheral surface 5a of the side wall 5 includes first to sixth sections 52A to F so as to correspond to the respective screw regions. It is.
Each screw region length t 1 of the upper screw thread 53 is shorter than each screw region length t 2 of the lower screw thread 54. In the axial direction, each screw region 53r of the upper screw thread 53 is present within a circumferential range of each screw region 54r of the lower screw thread 54. The circumferential centers of the screw regions 53r of the upper screw thread 53 and the screw regions 54r of the lower screw thread 54 coincide with each other.

  The first to sixth sections 52A to 52F are each configured with a rotation angle of 60 °. The plurality of screw region lengths t1 of the upper thread 53 are the same. The screw region lengths t2 corresponding to the first to fifth regions 52A to 52E of the lower thread 54 are the same, and the cutting start of the screw region 54r corresponding to the sixth region 52F of the lower thread 54 is tapered. It has become. Each screw region length t1 of the upper thread 53 in the first to fifth sections 52A to 52E is 60% of each screw region length t2 of the lower thread 54. Each screw region length t1 of the upper screw thread 53 in the sixth section 52F is 50% of each screw region length t3 of the lower screw thread 54. Also in the resin cap 50 of the present embodiment, the same effects as those of the fourth embodiment can be achieved, such as cost reduction and weight reduction.

  The embodiment disclosed above exemplifies the resin cap according to the present invention, and the shape, dimensions, and the like of each part are appropriately changed. For example, the screw thread may be formed only by the complete screw portion. In this case, there is no tapered portion formed at the end or start of the thread, and the axial width on which the force is applied on the side wall is more uniform over the entire circumference when forced. Can do. The present invention can also be applied to other types of resin caps that do not have a tamper evidence band. The container to which the resin cap of the present invention is applied is not limited, and the shape of the mouth is not limited. FIGS. 6 to 8 show examples in which each screw region length of the upper screw thread is shorter than each screw region length of the lower screw screw thread. It is good also as a resin cap which changed the thickness or changed the circumferential direction position of each upper screw field to each lower screw field.

1, 20, 40, 50 Resin cap 2 Cap body 3 Tamper evidence band 4 Top plate 5 Side wall 12, 21, 46 Thread 12a Start 12b End 21, 46, 51 Thread 22 Through groove 22A First loop through groove 22B Second groove 14 Groove 14 Female thread 23 Screw area 24 Groove area D Axial width 31a Screw width reduced part 42 Packing 47, 53 Upper thread t1 Upper thread area length 47r Screw area 48, 54 Lower thread t2, t3 Lower screw region length 48r, 54r Screw region 49A to G First to seventh regions 52A to F First to sixth regions 55 Cleaning hole

Claims (2)

In a resin cap having a top plate and a cylindrical side wall extending from the outer edge of the top plate, and having a screw thread that goes around the inner peripheral surface of the side wall,
The thread is formed with the same number of threads in the axial direction over the entire circumference of the side wall ,
A plurality of thread grooves in which a plurality of through-grooves communicating in the axial direction are regularly formed in the circumferential direction in the thread and the thread exists in the circumferential direction on the inner circumferential surface of the side wall, and the thread is A plurality of non-existing groove regions are regularly and alternately formed,
The screw thread is formed to have a length that makes two rounds on the inner peripheral surface of the side wall, and an upper screw thread that forms a one-turn area on the top plate side and a lower screw thread that forms a one-turn area on the side wall edge side. Consists of
Each screw region length of the upper screw thread is shorter than each screw region length of the lower screw thread, and each screw region of the upper screw thread in the axial direction is a circumferential direction of each screw region of the lower screw thread A resin cap characterized by being in the range . The cap body is constituted by the top plate and the side wall, and a tamper evidence band connected to the open end of the cap body via a plurality of breakable bridges is provided. Resin cap.

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