KR890002821B1 - Pilfer-proof plastic closure for containers - Google Patents

Abstract

A pilfer-proof plastic closure has break-off skirt lower section with double inclination intermal flaps (26). The pilferproof plastic closure of a vessel has a mouth-neck portion that has a outer-screw peak out outer surface and holding jaw portion at lower section of the outer screw peak (64). The closure are consisted by a top panel and a circular skirt portion that are prolonged downward from the top panel. The skirt portion forming a prolonged cutting line with respect to circumference (46). The circumference divides main section and the pilter-ploof floor section (14) of the skirt wall.

Description

Anti-theft Plastic Container Lid

1 is a partial cross-sectional side view of a blank according to one embodiment of the present invention.

FIG. 2 is a partial perspective view of the engagement flap in the blank of FIG.

3 is a partial rear view showing the engagement flap in the blank of FIG.

4 is a partial cross-sectional side view of the lid according to the acid embodiment of the present invention.

5 is a cross-sectional view taken along the line V-V of FIG.

FIG. 6 is a partial cross-sectional side view showing the lid of FIG. 4 mounted to the spout-neck of the container. FIG.

FIG. 7 is a side view showing a state in which the lid of FIG. 4 is detached therefrom after being mounted on the spout-neck of the container. FIG.

* Explanation of symbols for main parts of the drawings

2: blank 4: upper panel wall

6 skirt wall 8 annular protrusion

10, 16: step portion 14: theft prevention bottom portion

24: rethreaded thread 26: engagement flap

28: base edge 30: bending line

35: central axis 46: cutting line in the circumferential direction

48: cutting line in the axial direction 50: groove

52 bridge portion 52A high strength bridge portion

58: sealing liner 62: spout-neck

64: external thread 66: support jaws

The present invention relates to an antitheft plastic container lid, in particular an antitheft plastic for use in a container having a spout-neck having an external thread on its circumferential surface and a hoisting jaw portion below the external thread. It's about the lid.

Anti-theft metal lids for containers containing various beverages have recently been replaced by anti-theft plastic lids. Typical examples of such plastic container lids are shown in Japanese Laid-Open Patent Publication No. 7744/1981 and US Pat. No. 4,418,828.

The above mentioned lid has an upper panel wall and a cylindrical skirt wall extending downward from the circumferential edge of the upper panel wall. The skirt wall has a circumferentially extended cut line that divides the wall into a major portion above the cut line and an anti-theft bottom below the cut line. The circumferentially cut line consists of a plurality of circumferentially extending grooves spaced apart from each other in the circumferential direction, and a plurality of bridging portions located along the circumferential groove. An inner thread is formed on the inner surface of the main portion, and a plurality of radially inner projecting engagement flaps are formed at positions circumferentially spaced on the inner surface of the anti-theft bottom portion.

The plastic lid of this structure is used in a container with a spout-neck having an outer thread on its circumferential surface and a supporting jaw located below the outer thread. In order to seal the spout-neck of the container with the lid, the lid is inserted into the spout-neck and rotated in the sealing direction so that the outer thread of the spout-neck is fitted into the inner thread of the container. Thus, the lid is rotated in the closed direction with respect to the snout-neck and moved downward in the axial direction. At this time the support jaws formed on the outer surface of the spout-neck are in contact with the engagement flaps formed on the inner surface of the anti-theft bottom and bend them radially outwardly. When the engagement flap passes through the support jaw completely, the engagement flap elastically returns radially inward to be supported by the lower surface of the support jaw. To open the spout-abdomen of the container, turn the lid in the opening direction opposite to the sealing direction. Thus, the inner thread of the lid moves along the outer thread of the spout-neck and the lid rotates in the open direction while moving axially upward. However, the anti-theft bottom of the lid cannot move upward in the axial direction because the engaging flap formed on its inner surface is engaged under the support jaws of the spout-neck. Thus, significant stress is exerted on the bridge portions of the cut lines formed in the skirt walls of the lids. This breaks the bridge and separates the skirt wall into the main part and the anti-theft bottom. After that, the upper panel wall and the main part of the cut wall are separated from the spout-neck. The spout-neck is opened and the anti-theft bottom remains attached to the spout-neck.

It is important that the container lid having the above structure and function has the following two points. First, when the spout-neck of the container is sealed with a lid, the interlocking flap easily flexes elastically outward as the support jaws pass out, so that the spout-neck is mounted and broken with a relatively low rotational torque. It should be possible to reliably prevent the occurrence of excess stress in the bridge portion of the cutting line. second. When opening the spout-neck of the container, the engagement flap is fully engaged with the support jaw so that the bridge of the cutting line, such as the engagement flap bends radially outward and passes through the jaws, does not break, and the lid slides from the spout neck It must be able to prevent certain things. If this slip occurs, it will compromise the anti-theft properties of the lid. In order for the lid to meet these two points, the rotational torque generated on the lid is sufficiently reduced when the engagement flap passes from the top to the bottom of the support jaw, and the top of the lid when the engagement flap passes from the bottom to the support jaw upwards. It is necessary to sufficiently increase the upward rotational torque generated in the engine and to adjust the breakdown rotational torque that must be generated on the lid to break the bridge portion of the necessary cutting line to a size between the required upward rotational torque and the required downward rotational torque.

However, in the case of the conventional container lid, the difference between the required down-rotating torque and the up-rotating torque could not be set sufficiently, and due to manufacturing errors, a container suitable for the two points mentioned above could not be made.

On the other hand, if the anti-theft bottom is left attached to the spout-neck, it must be removed when the container is to be reused. However, this removal is very complicated. In addition, when the anti-theft bottom portion remains in the spout-neck and the main part of the removed upper panel wall and skirt wall is mounted again in the spout-neck, the bridge portion of the broken lid when opening the spout-neck is not damaged. It seems that the anti-theft properties of the lid cannot be fully exercised.

For this reason, in the plastic lid, the lid needs to be removed with the other part when opening the spout-neck as in the metal lid. In order to achieve this need, it is necessary to make at least one bridge portion with a higher strength than other bridge portions as in the case of a metal lid, and to form an axial cut line in the anti-theft bottom portion. In the case of using such a structure, the axial cut line can be broken when opening the spout-neck and the anti-theft bottom can be opened in the form of a tape.

In addition, the free portion having a high strength is maintained without being damaged. Thus, the anti-theft bottom opened in the form of a tape is left attached to the main part of the skirt wall by a higher strength bridge, and the anti-theft bottom can be removed from the spout-neck with the other parts of the lid.

In manufacturing the plastic container lid satisfying the above two points, the following problems due to the formation of the axial cutting line in the anti-theft bottom portion should be solved.

The axial cut lines are formed as so-called line holes or nicks as in metal lids. In such a case, after the cap flank is formed by injection molding or compression molding in the same way as the metal lid, the circumferential slits are simultaneously provided in the circumferential cut lines. It needs to be prepared separately. It is necessary to use a cutting tool on both the outside and the inner surface of the anti-theft bottom to provide the file hole or the notch on the anti-theft bottom. No problem arises if the working projection of the internal cutting tool used from the inner surface of the anti-theft bottom is less than the circumferential distance between the connected engagement flaps and properly positioned between the engagement flaps. In actual production, however, it is impossible or difficult to position the working projection of the internal cutting tool between the engagement flaps because the production speed is very fast. If the actuating projection of the inner cutting tool generates a large compressive force on the engagement flap and is not located between the engaging flaps and at least partially overlaps the engaging flap, it is easy to see that the actuating projection of the inner cutting tool is very deformed on the engaging flap. I can understand.

The first object of the present invention is to provide an anti-theft plastic container lid which can sufficiently reduce the required downward rotation torque, increase the required upward rotation torque and sufficiently provide a difference between the two rotation torques, thereby satisfying the two points mentioned above. To prepare.

A second object of the present invention is to provide an anti-theft plastic container lid which satisfies that the anti-theft bottom portion can be axially broken and opened in the form of a tape when opening the container without the above-mentioned problem.

Other objects of the present invention will be understood by the following description according to embodiments of the present invention.

In conventional plastic lids, each engagement flap formed therein is flipped in the opposite direction to the rotational direction of the lid while mounted on the spout-neck of the container and extends linearly continuously from the inner surface of the anti-theft bottom. The inventors of the present invention, by a number of experiments and investigations, have shown that each interlocking flap extends from the tip of the first portion and the first portion extending from the inner surface of the anti-theft bottom and at the same time for mounting the container on the spout-neck portion. If it is bent to provide a second part inclined toward the first part in the sealing direction of the container lid, the required upward rotational torque mentioned above can be greatly increased and at the same time can suppress the increase in the required downturning torque, ie It has been found that the first purpose can be achieved.

Thus, according to the present invention, there is provided an anti-theft plastic lid of a container having a spout-neck having an outer thread formed on its outer circumferential surface and a supporting jaw located under the outer thread, the lid comprising an upper panel and the upper Consisting of a cylindrical skirt extending downward from the panel, the skirt forming a circumferentially extending cut line dividing the skirt wall into a main portion above the cut line and an anti-theft bottom below the main portion on its inner surface. An inner thread engaging the outer thread on the spout-neck of the container, the anti-theft bottom forming a plurality of radially inner protruding engagement flaps in the circumferentially spaced body on its inner surface, Each engagement flap is defined by a first portion extending from the inner surface of the anti-theft bottom; There is provided a plastic lid, configured to have a second portion inclined toward the first portion from the tip of the first portion in the sealing direction of the lid for mounting the lid on the spout-neck.

In addition, the inventors of the present invention have found the following point by the factory investigation and experiment to manufacture the anti-theft plastic lid. (A) If a axial cut line with a groove or notch is formed on the antitheft bottom extending from its upper end to the upper end of its lower part or just below it, The anti-theft bottom is opened into the mold without the need to form grooves or nicks in at least a large portion of the lower part of the anti-theft bottom. (B) If at least a large part of the base edge of each engagement flap is located in the lower part of the anti-theft bottom where no axial cut line is formed, the axial cut line significantly deforms the engagement flap without reducing the manufacturing speed. It can be formed without application. This satisfies the second object of the present invention.

Further, according to the present invention, there is provided an anti-theft plastic lid of a container having a spout-neck having an outer thread and a supporting jaw beneath the outer thread on its circumferential surface, wherein the lid is formed of an upper panel wall and an upper panel wall. A cylindrical skirt wall extending downward from the circumferential edge, wherein the skirt wall forms a circumferentially extended cut line dividing the skirt wall into a main portion above the circumferential cutting line and an anti-theft bottom portion below the main portion; An inner thread is formed on its inner surface that engages an outer thread of the spout-neck portion of the container, and the anti-theft bottom has a plurality of radially inner protruding engagement flaps at positions circumferentially spaced on the inner surface thereof. And extending the axial cut line from the top end of the antitheft bottom in the antitheft bottom. At least a large portion of the bottom edge of each anti-theft bottom, wherein at least a large portion of the base edge of each engagement flap is positioned in the lower portion of the anti-theft bottom without axial cut lines. I am preparing.

The invention is explained in more detail below in accordance with the accompanying drawings.

1 shows a lid blank made by one embodiment of a lid constructed in accordance with the present invention. The blank 2 formed of a suitable plastic material, such as polypropylene or polyethylene, by injection molding or compression molding, has a circular shape. It has an upper panel wall 4 and a cylindrical skirt wall 6 extending downward from the circular edge of the upper panel wall 4. An annular projection 8 is formed at the upper end of the inner surface of the cut wall 6 so as to project radially inward from the upper end.

The lower portion of the circumferential surface of the skirk wall 6 is formed with a stepped portion 10 entering in the inner radial direction.

The portion 12 above the constant step portion 10 has a top wall thickness while the thickness of the anti-theft bottom portion 14 below the step portion 10 is reduced.

In the embodiment shown, a step portion 16 is also formed on the inner circumferential surface of the skirt wall 6 below the step portion 10, and the anti-theft bottom portion 14 is a thick upper portion over the step portion 16. It consists of a thin lower portion 20 below the portion 18 and the step portion 16. The thickness t ₁ of the lower portion 20 of the anti-theft bottom portion is thin and is 0.05 to 0.75 mm, preferably 0.20 to 0.50 mm. The thickness t ₂ of the thick upper portion 18 is 0.50 to 1.10 mm, preferably 0.75 to 0.85 mm. If necessary, the thickness t ₂ of the thick upper portion 18 may be as small as the thin lower portion 20 (thus, the step portion 16 is not formed). A corrugated handle portion 22 is formed on the outer circumferential surface of the portion 12 of the skirt wall 6 so that the fingers do not slip when holding the lid. An internal thread 24 is formed on the inner circumferential surface of the portion 12 of the cut wall 6. A plurality of engagement flaps 26 spaced in the circumferential direction are formed on the inner circumferential surface of the anti-theft attachment portion 14 of the skirt wall 6. Each engagement flap 26 projects radially inward from its base edge 28 connected to the inner circumferential surface of the anti-theft bottom 14. It is important that at least a large portion of each engagement flap 26 is located in a thin lower portion 20 below the step portion 16 in the anti-theft bottom portion 14. In the embodiment shown, the upper end of the base edge 28 of each engagement flap 26 is positioned to align with the step 16. Thus, the base edge 28 of the interengagement flap 26 is located in the thin lower portion 20 below the step 16.

a

85°, 양호하게는 20°

a

80° 또는 30°

a

70°이다. 굴곡선(30)으로부터 방사상 내측으로 연장된 제2부분(34)은 상기 밀폐방향안의 제1부분(32)에 대하여 경사져서 연장되어야만 한다. 제1부분(32)에 대한 제2부분(34)의 경사각(β)은0°

β

90°, 양호하게는 0

β

70° 또는 5°

β

45°이다. 굴곡선(30)은 거의 평행으로 연장되고, 이에 따라 블랭크(2)의 (제1도의) 중심축(35)에 거의 수직이거나 부분(20)의 내부 표면에 근접하여 하향 경사질 수 있다. 양호하게는, 이는 얇은 하부부분(20)으로부터 멀어지는 방향으로 하향경사져 있다. 얇은 하부부분(20)의 내부 표면으로부터 멀어지는 하향 방향에 대한 굴곡선(30)의 경사각(α)은 5°

α

80°, 향호하게는 10°

α

60°또는 20°

α

50°이다.According to the present invention, the following features are formed in the interlocking flap 26. According to FIGS. 1 and 3, each engagement flap 26 bends along the bend line 30 and extends from the base edge 28 to the bend line 30 with the first portion 32. It is formed by a second portion 34 extending from the bend 30 to its free end. The base edge 28 extends substantially parallel and thus extends substantially perpendicular to the central axis 35 (of FIG. 1) of the blank 2. However, if necessary, the base edge 28 may be inclined in an appropriate direction with respect to the central axis 35 (of FIG. 1) of the blank 2, ie counterclockwise, second from the top of FIG. 1. To mount the lid on the spout-neck of the container (in the direction of arrow 36 in FIGS. 3 and 3), it may be inclined downward at an appropriate angle relative to the direction of sealing the lid or in the opposite direction. Preferably, the first portion 32 is inclined in a direction opposite to the sealing direction and extends radially inward to the bottom edge 29. The inclination angle a of the first portion 32 with respect to the inner surface of the portion 20 is 5 °

a

85 °, preferably 20 °

a

80 ° or 30 °

a

70 °. The second portion 34 extending radially inward from the curve 30 must extend inclined with respect to the first portion 32 in the sealing direction. The inclination angle β of the second portion 34 with respect to the first portion 32 is 0 °.

β

90 °, preferably 0

β

70 ° or 5 °

β

45 °. Flexion line 30 extends substantially parallel and thus may be nearly perpendicular to central axis 35 (of FIG. 1) of blank 2 or inclined downward close to the inner surface of portion 20. Preferably it is inclined downward in a direction away from the thin lower portion 20. The inclination angle α of the bend line 30 with respect to the downward direction away from the inner surface of the thin lower portion 20 is 5 °.

α

80 °, preferably 10 °

α

60 ° or 20 °

α

50 °.

δ₁

30瀚이고, 경사각(δ₂)은 20

δ

50°이다. 제1도와 함께 제4도에 의하면, 본 발명의 용기 뚜껑을 제조하기 위하여, 블랭크(2)안에 원주 방향의 절단선(46)을 형성하고, 양호하게는 원주 방향의 절단선(46)을 마련함과 동시에 축방향의 절단선(48)을 블랭크(2)에 형성한다. 원주방향의 절단선(46)은 스텝부(10) 바로 아래에 형성하고, 이에 따라 스텝부(10)위에 상당한 충분한 두께를 갖는 부분(12)은 스커트벽(6)의 주요부를 구성하고, 비교적 두꺼운 상부부분(18)과 비교적 얇은 하부부분(20)은 스텝부(10) 아래의 감소된 두께를 갖는 도용 방지 바닥부(14)를 구성한다. 원주 방형의 절단선(46)자체는 다수의 원주방향으로 간격을 형성하고 연장된 홈(50), 홈(50)을 따라 위치한 다수의 브리지부(52)로 구성된다. 예를들어 도용 방지 바닥부(14)는 브리지부(52)를 통하여 스커트벽(6)의 주요부 또는 부분(12)에 연결된다. 다수의 브리지부(52)중 한개의 고강도 브리지부(52A)는 다른 브리지부(52)보다 원주방향의 길이보다 크고 높은 강도를 갖는 고강도 브리지부로서 형성한다.As shown in FIGS. 1 and 2. The upper edge 38 of the first portion 32 extends inclined downward in a radially inward direction which generally forms a smooth curve, and the upper edge 40 of the second portion 34 extends almost vertically. On the other hand, the lower edge 42 of the first portion 32 and the lower edge 44 of the second portion 34 are inclined in the radially inward direction and extend upward. In general, the inclination angle δ ₂ of the lower edge 44 of the second portion 34 is slightly larger than the inclination angle δ ₂ of the lower edge 42 of the first portion 32. Typically the angle of inclination (δ ₁ ) is 10 °

δ ₁

30 ° and the inclination angle δ ₂ is 20

δ

50 °. According to FIG. 4 along with FIG. 1, in order to manufacture the container lid of this invention, the circumferential cutting line 46 is formed in the blank 2, Preferably the circumferential cutting line 46 is provided. At the same time, the cutting line 48 in the axial direction is formed in the blank 2. A circumferential cut line 46 is formed just below the step portion 10, so that the portion 12 having a sufficient sufficient thickness over the step portion 10 constitutes the main portion of the skirt wall 6, and is relatively The thick upper portion 18 and the relatively thin lower portion 20 constitute an anti-theft bottom portion 14 having a reduced thickness below the step portion 10. The circumferential rectangular cutting line 46 itself consists of a plurality of bridge portions 52 which are spaced in a plurality of circumferential directions and extend along the groove 50 and the groove 50. For example, the anti-theft bottom portion 14 is connected to the main portion or portion 12 of the skirt wall 6 via the bridge portion 52. One of the high-strength bridge portions 52A of the plurality of bridge portions 52 is formed as a high-strength bridge portion having a greater strength and a greater circumferential length than the other bridge portions 52.

In this embodiment, two axial cutting lines 48 are provided in the circumferential direction at predetermined intervals, but one or three or more of these axial cutting lines may be provided. One of the axial cutting lines 48 is provided adjacent to one end of the high strength bridge portion 52A as shown in the circumferential direction, and the other is provided adjacent to the other end of the high strength bridge portion 52A. The axial cut line 48 extends downward from the top end of the antitheft bottom 14 but to the upper end of the relatively thin lower part 20 of the antitheft bottom 14, and thus to the step 16. Or extends slightly below it, and it is important that at least it is not present in many parts of the relatively thin lower part 20. The cutting line 48 in the axial direction is substantially parallel to the axis 35 or has a slight inclination with respect to the axis 35. The cutting line 48 itself in the axial direction is formed by a groove formed by completely cutting the material, or by a perforated notch formed by partially cutting the material in the thickness direction. According to FIG. 4 together with FIG. 5, each illustrated axial cut line 48 extends from the upper end of the anti-theft bottom 14 to the step 16 so that the anti-theft bottom ( A groove 54 extending along the thick upper portion 18 of 14 and a relatively thin lower portion 20 of the anti-theft bottom 14 extending downwardly over a distance along the groove 54 (thus). It consists of a notch 56). In the notch 56, the cutting depth of the material decreases gradually as it extends downward. Thus, the thickness of the remaining material gradually increases as it extends downward.

With regard to the axial cut line 48, the following fact should be noted. In forming the circumferential cutting line 46, more specifically the groove 50, or at the same time or separately from the axial cutting line 48, more specifically the groove 54 and the nick 56 , Using an external cutting tool having a groove 54 formed at its peripheral edge from the outer circumferential surface of the blank 2 and a cutting edge according to the notch 56 and the groove 50 and at the same time the inside thereof. There is a need to use an internal cutting tool with an actuating protrusion that works reciprocally with the cutting edge from the circumferential surface to the blank. However, the axial cut line 48 extends to or just below the upper end of the relatively thick upper portion 18 of the anti-theft bottom 14 and is present in at least a large portion of the relatively thin lower portion 20. I never do that. Thus, it is not necessary to use the working projection of the internal cutting tool in at least a large part of the relatively thin lower part 20. In addition, at least a large portion of the base edge 28 of each engagement flap 26 is located in the relatively thin lower portion 20. Thus, the axial red line 48 can be molded without the need for work to set the angle at a set position between the blank 2 and the internal cutting tool, which is complex and rapidly reduces efficiency. This also avoids deforming the engagement flap 26 by the large compressive force of the working projection of the internal cutting tool.

It should be noted that the formation of the cut line 48 in the axial direction is as follows. When the angle between the blank 2 and the external and internal cutting tools is set at a preset position in which the axial cutting line 48 is provided, the efficiency is rapidly reduced as mentioned above. Therefore, it is necessary to perform the cutting operation without setting the angle in particular. In the case where the cutting operation is performed without setting the angle in particular, the cutting line 48 in the axial direction is formed at an arbitrary angular position. When opening the lid, the relatively thin lower portion 20 of the anti-theft bottom 14 must break along the axial cut line 48. When the axial cutting line 48 is formed at an angular position overlapping or aligned in line with the base edge 28 of the engagement flam 26, the relatively thin lower portion 20 is defined by the engagement flap 26. It is hard to break. Due to this fact, the engagement flaps 26 are arranged circumferentially at equal intervals in the present embodiment, and the circumferential distance CD of the two cutting lines 48 is defined by the circumferential pitch of the engagement flaps 26. It is set according to the following formula regarding the circumferential width W of the base edge 28 of the engagement flap 26 with P).

(n + 1) p­ W ＞ cd ＞ np + W

(Where n = 0, or a positive integer)

In this condition, at least one of the two axial cut lines 48 is located at an angular position that does not overlap or line up with the base edge 28 of the engagement flap 26. Thus, when opening the lid, the relatively thin lower portion 20 of the anti-theft bottom 14 can be reliably and easily broken according to the breakage of at least one of the two axial cut lines 48.

In addition, according to FIG. 4, after or before providing the circumferential cutting line 46 or the axial cutting line 48, the sealing liner 58 of a suitable plastic material is formed by the upper panel wall of the blank 2. On the inner surface of 4), it may be formed in more detail on the annular projection 8 formed on the inner surface of the upper panel wall (b). The formation of the sealing liner 58 can be made by known molding methods. Instead of forming the sealing liner 58 separately, an appropriately shaped sealing protrusion may be integrally formed on the inner surface of the upper panel wall 4 of the blank 2.

The final lid 60 thus shaped can be used in a container having a spout-neck 62 of the type shown in FIG. On the cylindrical circumferential surface of the spout-neck portion 62 an outer thread 64 and a support jaw 66 beneath it are formed.

In order to seal the spout-neck 62 with the lid 60, the lid 60 is pushed over the snout-neck 62 and then rotated in a closed direction, ie clockwise for the purpose of FIG. 6. Thus, the inner thread 24 formed on the lid 60 engages with the outer thread 64 formed on the spout-neck 62 and the lid 60 moves downward in the axial direction. The false engagement flap 26 formed in the lid 60 passes through the support jaws 66 through a thread formed on the spout-neck 62. While passing over the support jaws 66, each engagement flap 26 is interfered by the support jaws 66 and is elastically bent radially outward. When the inner thread 24 of the lid 60 is fully engaged with the outer thread 64, each engagement flap 26 passes completely through the support jaws 66 and is freed from interference by the support jaws 66. do. Thus, the engagement flap 26 elastically returns to its original state.

The required downward rotational torque present on the lid 60 of the present invention while the engagement flap 26 elastically deforms over the support jaws 66 is the second portion 34 of each engagement flap 26. ) Is approximately equal to the downward rotational torque of a conventional container lid which does not bend with the first portion 32 and extends in a straight line with the first portion 32 as shown by the two-dot chain line in FIG. Low enough, it may be understood in more detail by the experiments and comparative experiments described below. Thus, during mounting the lid on the spout-neck portion 62, it is possible to prevent excessive stress from occurring in the cutting lines 46 and 48 and thus to reliably prevent breakage.

When the engagement flap 26 is fully returned to its original state, it will engage the lower surface of the support jaw 66 as shown in FIG. When the inner thread 24 of the lid 60 is fully engaged with the outer thread 64 on the spout-neck 62, the sealing liner 58 is in close contact with the end face portion of the spout-neck-neck 62. In contact to seal the spout-neck 62.

To open the spout-neck 62, the lid 60 is rotated counterclockwise than in the opening direction, for example from above in FIG. 6. The inner thread 24 of the lid 60 moves along the outer thread 64 of the spout-neck 62 and the lid 60 moves along the outer thread of the spout-neck 62 upon rotation. However, the anti-theft bottom portion 14 cannot move upward in the axial direction because the engagement flap 26 is formed on its inner surface and engages with the lower surface of the support jaw 66 of the spout-neck. Therefore, considerable stress is generated on the circumferential cut line 46 and more particularly on the bridge portion 52. Therefore, the bridge portion 52 of the circumferential cut line 46 is broken, leaving the high strength bridge portion 52A as shown in FIG. As also shown in FIG. 7, the relatively thin portion 20 of the anti-theft bottom 14 breaks upon breakage of at least one of the two axial cut lines 48. Thus, the anti-theft bottom portion 14 is opened in the form of a tape, and the engagement flap 26 is not engaged with the lower surface of the supporting jaws 66. Regarding the breakage of the relatively thin portion 20, if the thickness t ₁ of the thin lower portion 20 is sufficiently thin, such as 0.05 to 0.75 mm, preferably 0.20 to 0.50 mm, the thin lower portion 20 is carved. Experimentally demonstrated that the fracture along the axial cut line 48 without fail to form an eye lamp was confirmed. After the anti-theft bottom portion 14 is opened in the form of a tape and the engagement flap 16 is not engaged with the lower surface of the supporting jaw portion 66, the main portion (52A) is not broken and is broken. The entire lid 60 comprising the anti-theft bottom 14 connected to 12 is moved axially upward by rotating. Thus, the entire lid 60 is removed from the snout-neck 62 and the snout-neck 62 is opened.

As will be more clearly understood by the following experiments and comparative experiments, in the case of the lid 60 of the present invention, the engagement flap 26 may include the second portion 34 of each engagement flap 26 in the first portion ( More rigidly engaged with the lower surface of the support jaw 66 than in the case of a conventional lid which does not bend relative to 32 and extends linearly with the first portion 32 as shown by the dashed-dotted line in FIG. All. In other words, the required upward rotational torque that must be generated on the lid 60 of the present invention as the engagement flap 26 passes elastically bent over the support jaws 66 is considerably greater than the torque generated in conventional lids. Big. Thus, the lid 60 can be reliably prevented from being removed from the spout-neck without the necessary breaks of the cutting lines 46, 48, and can maintain the anti-theft characteristics of the lid 60.

If necessary, it is possible to arrange the support protrusion on the outer surface of the anti-theft bottom 14, preferably adjacent the right side of one of the cutting lines 48, so that from the spout-neck 16 the lid ( On opening by removing 60, the support protrusion is pushed to break the cutting line 46, and at the same time it is pushed to break the cutting line 48 completely, after which the lid 60 is moved upward in FIG. From now on, it will rotate counterclockwise.

Experiment

Ten blanks of the same shape as the blanks 2 shown in FIGS. 1 to 3 were molded from a polypropylene with a melt index of 2.0 and a density of 0.90. Each blank has an inner diameter (d) of 25.4 mm of the inner thread, an outer diameter (D) of the upper part of 30.0 mm, and a total height (H) of 19.0 mm. Each engagement flap 26 formed on the inner surface of the thin lower portion 20 has the following dimensions.

Thickness (W): 0.35mm

Length of lower edge 42 of first portion 32

(l ₁ ): 1.9mm

The length of the lower edge 44 of the second portion 34

(l ₁ ): 2.0mm

Tilt angle (α): 50 °

Tilt angle (β): 10 °

Tilt angle (α): 30 °

Tilt angle (δ ₁ ): 20 ° _°

Tilt angle (δ ₂ ): 45 °

The upper edge 38 of the first portion 32 was arcuate with a radius of 0.5 mm, and the upper edge 40 of the second portion 34 was almost horizontal.

Each blank was mounted on the spout-neck 62 of a glass vessel with a nominal diameter of 28 mm in the form shown in FIG. 6 and the required downward rotational torque was measured.

After that, the blank was forcibly removed from the snout-neck 62 and the required upward rotational torque was measured. The results are shown in Table 1 below.

[Comparison Experiment]

For comparison, a point where each engagement flap 26 formed on the inner surface of the portion 20 has the shape shown by the dashed-dotted line in FIG. 3 (ie, the second portion 34 is the first portion 32). Ten blanks as in the above experiments were molded, except that they did not bend relative to, but extend linearly to the first portion 32).

In the same way as in the experiment, the required downward rotation torque and the required upward rotation torque were measured. The results are shown in Table 1.

TABLE 1

Claims (27)

A cylindrical with its outer thread formed on its outer circumferential surface and provided with a spout-neck having a support jaw below the outer thread, the lid extending downward from the peripheral edges of the upper panel wall 4 and the upper panel wall 4; A circumferentially extended cut comprising a skirt wall (6), which divides the skirt wall (6) into the skirt wall (6) into a main portion (12) above the cut line and an anti-theft bottom portion (14) below the cut line. Form a line, the main portion 12 having an internal thread on its inner surface that engages an external thread on the spout-neck portion 62 of the container, and the anti-theft bottom 14 on its inner surface. An anti-theft plastic lid of a container having a plurality of radially inwardly protruding engagement flaps at circumferentially spaced positions, wherein each engagement flap 26 extends from an inner surface of the anti-theft bottom portion; And a second portion 34 extending obliquely to the first portion 32 from the tip of the first portion 32 in a sealing direction for mounting the lid on the flour 32 and the spout-neck portion 62. Theft prevention plastic container with lid. The anti-theft plastic container lid according to claim 1, wherein the first portion (32) extends from the inner surface of the anti-theft bottom portion (14) inclined in a direction opposite to the sealing direction. The angle of inclination α of the first portion 32 with respect to the inner surface of the anti-theft bottom at the base edge 28 of the flap is 50 °.

α

Antitheft plastic container lid, characterized in that the 85 °. The angle of inclination (α) of claim 3, wherein

α

An antitheft plastic container lid, characterized in that it is 80 °. The angle of inclination (α) of claim 4 is 30 degrees.

α

An antitheft plastic container lid, characterized in that it is 70 °. The inclination angle β of the second portion 34 with respect to the first portion 32 is 0 °.

β

An antitheft plastic container lid, characterized in that it is 90 °. 7. The angle of inclination β of claim 6 is zero degrees.

β

Antitheft plastic container lid, characterized in that the 70 °. 8. The angle of inclination β according to claim 7, wherein

β

Antitheft plastic container lid, characterized in that the 45 °. 2. The flexure line 30 between the first portion 32 and the second portion 34 extends downward but away from the interior surface at the base 20 of the lower portion 20 of the anti-theft bottom 14. Anti-theft plastic container lid, characterized in that inclined at the corner (28) of the flap (26). 10. The angle of inclination α of the bend line 30 with respect to the direction away from the inner surface of the lower portion 20 of the antitheft bottom 14 is 5 °.

α

Theft theft plastic container lid, characterized in that it is 80 °. The angle of inclination (α) of claim 10 is 10 degrees.

α

Anti-theft plastic container lid, characterized in that it is 60 °. 11th, the inclination angle α is 20

α

An antitheft plastic container lid, characterized in that it is 50 °. The upper edge 38 of the first portion 32 extends radially inward and is inclined downward, and the upper edge 40 of the second portion 34 extends almost horizontally. Theft prevention plastic container with lid. The anti-theft plastic container lid according to claim 13, wherein the upper edge (38) of the first portion (32) forms a gentle curve. The anti-theft plastic container as claimed in claim 1, wherein the lower edge 42 of the first portion 32 and the lower edge 44 of the second portion 34 extend radially inwardly and are inclined upwards. Lid. The lateral cutting line 48 extends downwardly from the upper end of the lower portion 20 of the antitheft bottom portion 14 and is formed in the lower portion 20 of the antitheft bottom portion 14. Theft protection is not present in at least a large portion of the lower portion 20 of the bottom portion 14, and at least a large portion of the base edge of each engagement flap 26 is an antitheft where no axial cut line 48 is present. Anti-theft plastic container lid, characterized in that located in the lower portion 20 of the bottom portion (14). The upper portion 18 of the anti-theft bottom portion 14 has a relatively thick thickness, the lower portion 20 has a relatively thin thickness, and an axial cut line 40 has the upper portion. An anti-theft plastic container lid characterized in that it extends to or just below the lower end of the portion. 18. The anti-theft plastic container lid according to claim 17, wherein the axial cutting line (48) is a groove or notch and gradually increases as the thickness of the remaining material extends in the lower end portion thereof. 18. The anti-theft plastic container lid according to claim 17, wherein the relatively thin lower portion (20) of the anti-theft bottom portion (14) has a thickness t ₁ of 0.05 to 0.75 mm. 20. The anti-theft plastic container lid according to claim 19, wherein the thickness t ₁ is 0.20 to 0.50 mm. 17. The circumferential cutting line 46 is defined by a plurality of circumferentially spaced grooves 50 extending in the circumferential direction and a plurality of bridge portions 52 located along the circumferential grooves. And at least one of the bridge portions is a high strength bridge portion 52A having a higher strength than the other bridge portions, and an axial cut line 48 is closer to the circumferential end of the higher strength bridge portion 52A in the circumferential direction. Theft prevention plastic container lid which is specially located. A cylindrical with its outer thread formed on its outer circumferential surface and provided with a spout-neck having a support jaw below the outer thread, the lid extending downward from the peripheral edges of the upper panel wall 4 and the upper panel wall 4; A circumferentially extended cut comprising a skirt wall (6), which divides the skirt wall (6) into the skirt wall (6) into a main portion (12) above the cut line and an anti-theft bottom portion (14) below the cut line. Form a line, the main portion 12 having an internal thread on its inner surface that engages an external thread on the spout-neck portion 62 of the container, and the anti-theft bottom 14 on its inner surface. In the anti-theft plastic lid of a container having a plurality of radially inwardly engaging engagement flaps at circumferentially spaced positions, an axial cut line 48 is a lower portion 20 of the anti-theft bottom 14. To the upper end of Is formed in the lower portion 20 of the anti-theft bottom portion 14 but is not present in at least a large portion of the lower portion 20 of the anti-theft bottom portion 14 and the base of each engagement flap 26. An anti-theft plastic container lid, characterized in that at least a large portion of the edge is located in the lower portion (20) of the anti-theft bottom portion (14) where there is no axial cut line (48). 23. The upper portion 18 of the anti-theft bottom portion 14 has a relatively thick thickness, the lower portion 20 has a relatively thin thickness, and an axial cut line 48 has the upper portion. An anti-theft plastic container lid, characterized in that it extends to a point just below it, turning to the lower end of the portion. 24. The anti-theft plastic container according to claim 22 or 23, wherein the axial cut line 48 is a groove or notch and gradually increases as the thickness of the remaining material extends downward in the lower portion thereof. Lid. The antitheft plastic container lid according to claim 23, wherein the relatively thin lower portion (20) of the antitheft bottom portion (14) has a thickness t ₁ of 0.05 to 075 mm. The anti-theft plastic container lid according to claim 25, wherein the thickness t ₁ is always 0.20 to 0.50 mm. The circumferential cutting line 46 is spaced in a plurality of circumferential direction, and the plurality of bridge portions located along the circumferential groove 50 and the circumferential groove 50. 52, wherein at least one of the bridge portions is a high-strength bridge portion 52A having a higher strength than the other bridge portions, and the cutting line 48 in the axial direction is circumferentially seen in the circumferential direction. An anti-theft plastic container lid, characterized in that it is located adjacent the end.

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