JPH06183449A - Screw cap with loosening stopper and manufacture of the same - Google Patents

Abstract

PURPOSE:To provide a very reliable loosening stopping mechanism by a to a mold for method wherein a core pin to be drawn out by rotation is used a cap which has on its external surface a screw groove corresponding to a screw thread provided on its internal surface, and a cutout formed at a part distant from a starting end on an inlet side of the screw thread by less than one cycle is engaged with an engaging projection of a container mouth. CONSTITUTION:An inner screw thread 3 on an inside diameter surface of a plastic screw cap 1 is made by an injection molding, wherein a core-pin-shaped molding metal die, on whose external surface a screw groove shaped corresponding to the inner screw thread 3 is formed, is drawn out while rotating. The screw thread 3 is cut out at a part distant from a starting end 9 on an inlet side of the screw thread by less than one cycle, and the cutout part 5 is engaged with an egnaging projection which is provided at an outer screw part of a container mouth, so that it may engage with the cap 1. This mechanism serves as a loosening stopper of the screw. In this instance, there is no problem in the manufacture, if the condition that the cutout part 5 is provided at a part distant from the starting end 9 on the inlet side of the screw thread by less than one cycle. In addition, it is desirable that the starting end 9 of the screw thread is tapered sharply.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw cap that is screwed into the mouth of a container such as a cosmetic container, and more specifically,
The present invention relates to a screw cap with an anti-loosening lock, in which internal threads formed on an inner diameter surface of a cap are partially cut out, and the notched portion can be used to stop loosening of a screw.

[0002]

2. Description of the Related Art A number of techniques have been proposed in the related art in which a screw cap and a container screw portion are provided with protrusions and recesses for engaging with each other to prevent the screw from loosening (Japanese Patent Laid-Open No. 54-17).
955 etc.). However, the reality is that the products corresponding to these proposals are not yet commercialized. The reason is that there has never been a plastic screw cap with a locking mechanism that has a good screw shape and can be manufactured by a highly productive injection molding method.

Plastic screw caps are roughly classified into two types. One is a screw cap having a thread with a comparatively gentle cross-sectional shape, which is formed by a so-called stripper method. The stripper method is a method in which after injection molding, the core pin for forming the inner screw of the cap is pulled out without rotating. The plastic that flows into the thread groove on the outer periphery of the core pin and solidifies forms the screw thread of the cap, but when the core pin is pulled out, the cap is deformed (expansion, mainly elastic deformation),
Since the thread of the core pin is pulled out beyond the thread of the cap that extends to the outside, the thread of the cap is not destroyed. However, in the case of a screw having a mountain height that exceeds the deformability of plastic or a screw having an acute angle in which the surface slip between the core pin and the cap does not easily occur, it is difficult to pull out the core pin without breaking the screw thread.

Another type is a screw cap having a screw thread having a relatively sharp cross-sectional shape, which is molded by a core pin rotation method. In the core pin rotation method, after injection molding, the core pin is pulled out while rotating. At the time of extraction, there are a method of stopping the rotation of the cap and rotating the core pin, and a method of rotating and extracting the core pin in synchronization with the screw pitch.

The disadvantages of the stripper method are that the cross-sectional shape of the threads cannot be made high and sharp, and that a hard plastic cap cannot be manufactured. Therefore, there is a problem that a screw cap that can be firmly screwed in and that maintains airtightness cannot be obtained. This problem is particularly significant when a creamy, creamy cosmetic product adheres to the screw portion.

The core pin rotation method does not have the drawbacks of the stripper method described above. However, a problem arises when an attempt is made to obtain a screw cap having unevenness different from the screw shape in the inner screw portion (thread crest / screw trough) of the screw cap. For example, if you try to make a screw with a part of the thread cut out from the root and fill the part of the threaded groove of the core pin that corresponds to that notch, when you see the part that is filled in from the groove, the groove It means that the project is on. This protrusion, when the core pin is rotationally pulled out after molding, scrapes off the screw thread of the cap formed in the course of the protrusion.
Therefore, it is impossible to provide a screw thread first from the cutout portion, that is, it is impossible to provide a cutout portion in the middle of the screw.

In another conventional type of screw cap, the inner screw portion and the locking engagement portion are formed by separate parts,
A method of incorporating both into a separate cap was also used. This type of screw cap had both a good screw shape and a locking mechanism, but the cost of manufacturing and assembling parts was high.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a screw cap having the following characteristics, which have not been obtained in the prior art, and a manufacturing method thereof. Has a sharp and high screw shape. It has a highly reliable anti-loosening mechanism that will not loosen even if there is a reduction in friction caused by vibrations when carrying the container or adhesion of contents. You can tighten it tightly. Mass production is possible and cost can be kept low. Overrun (over tightening of screws) can be prevented. It is also possible to integrally form the locking portion and the screw portion.

[0009]

A screw cap with locking device according to the present invention is a plastic screw cap having a cap body having an inlet and an internal screw provided on the inner surface of the cap body. The thread of the inner screw is
Using a molding die core pin having a thread groove of a shape corresponding to this on the outer surface, plastic is injected into this thread groove, and then this core pin is molded by rotating and withdrawing, and the inner thread is The screw thread has a notch in a portion within one round from the inlet side start end of the screw thread, and the notch portion engages with a coupling protrusion provided on the container mouth where the cap fits, thereby screwing. It is characterized in that it can be used as an anti-loosening agent.

Further, according to the method of manufacturing the screw cap with locking device of the present invention, the core pin having the outer peripheral surface with the thread groove cut, and the slide capable of advancing in the axial direction of the core pin so as to fill a part of the thread groove. Using a mold including a top; plastic is injected into a cavity of the mold with the slide piece filling a part of the screw groove, and then the slide piece is retreated to the outside of the screw groove, After that, the core pin is extracted by rotation.

[0011]

The mechanism for preventing the screw cap from loosening according to the present invention operates as follows. There is a notch on the inner thread of the screw cap. The mouth-side screw part of the container is provided with a protrusion that engages with the notch, and the two engage with each other at an appropriate time when the cap is tightened. Even if a force is applied to the cap in the loosening direction, the end of the engaging projection abuts the end of the screw thread formed on the inlet side of the notch, and the cap does not rotate in the loosening direction.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A screw cap and its molding die according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a screw cap 1 for a nail varnish container according to an embodiment of the present invention. The screw cap body 2 has a cylindrical shape with a top, and has an inlet 10 on the lower surface for receiving the container mouth. Inner threads 3 are formed on the inner surface of the screw cap body 2. The inner screw thread 3 is partially cut off around a point entering from the screw thread starting end 9 of the inner screw thread 3 about 45 ° on the screw circumference to form a cutout portion 5. There is. The screw cap of this embodiment has an inner thread having a root diameter of 14 mm and a mountain diameter of 12
mm, the screw height is 1 mm, the angle of the top of the screw thread is 50 °, the screw pitch is 2.54 mm, and the width of the notch 5 is 4 mm. In terms of performance, the screw cap of the present invention preferably has a screw height of 5 to 15% of the root diameter of the inner screw, and in the case of a triangular screw, the top angle of the screw thread is preferably 40 to 60 °. If the notch 5 is notched at a portion within one turn from the inlet-side screw thread starting end 9, there is no problem in manufacturing.

In the present embodiment, the cross-sectional shape of the front screw thread 7 of the notch portion is the same as the screw thread of the other portion (from the notch to the back side) in this embodiment. It is preferable that the screw thread of the inlet side thread start end 9 is tapered so that the thread can be smoothly guided to the thread trough at the beginning of screwing.

The cross-sectional shape of the screw thread 7 on the front side of the notch portion can be made narrower or lower than the cross section of the screw thread of the other portion. It is also possible to cut the top of the triangular cross section and leave the root to make a trapezoid. Furthermore, the cross-sectional shape can be round (semicircle). The engagement protrusion 15 (FIG. 2) on the container mouth side and the front screw thread 7 of the cutout portion interfere with each other at the final stage of screwing the cap, so that frictional resistance at that time, damage to the screw thread by friction, and loosening prevention The shape of the screw thread 7 can be determined in consideration of performance and the like.

The length of the screw thread 7 on the front side of the notch is equal to that of the screw 1.
1/12 to 1/2 of the circumference is preferable. At the final tightening portion of the cap screw, the screw thread 7 and the engaging projection 15 on the container mouth 11 side interfere with each other to cause a cap rotation resistance. Can be sensed and a pleasant feeling of use can be obtained.

In this embodiment, the notch 5 has a thread cut out from the root of the screw. It is also possible to cut out from the middle of the thread, that is, leaving the root of the screw a little. It is also possible to use a screw-shaped center line method or a partial notch in an oblique direction.

The material of the screw cap of this embodiment can be selected from polypropylene, low-pressure polymerized polyethylene, ABS, AS, POM and the like.

FIG. 2 is a partial sectional front view of a container port into which the screw cap of FIG. 1 is fitted. An outer thread 13 is formed on the outer peripheral surface of the container port 11. An engaging protrusion 15 is provided below the outer thread 13 so as to travel upward from the outer thread 13 to the thread groove 16. The engagement protrusion 15 is at the final stage of screwing the screw cap 1 into the container opening 11,
It interferes with the inner thread 7 on the front side of the notch of the cap. When the cap is screwed in beyond the interference resistance, the engagement protrusion 15 advances to the inner side while rubbing against the inner thread 7 on the front side of the notch due to elastic deformation of the thread cap or the thread. And finally,
Fit into the notch 5 of the cap 1.

At the time when the engaging projection 15 is fitted into the cutout portion 5, the end 14 of the engaging projection on the rear side abuts against the end portion 4 on the recessed side of the rear thread, so that the cap cannot be screwed any more. For this reason, the overlining of the screw is eliminated, and plastic deformation of the screw due to over-tightening and deviation of the cap mounting angle can be prevented.
Further, the front-side engaging projection end 16 contacts the front-side thread ridge cut-out end portion 6, locks the movement of the screw in the loosening direction, and the screw does not loosen when the container vibrates.

Other than the embodiment, the shape of the engaging projection 15 is such that one travels from the top to the bottom, one provided so as to connect the upper and lower outer threads 13 and one that travels so as to face each other from the top and bottom. Can be used.

The loosening prevention engaging portion (cap screw notch portion 5 and container mouth engaging protrusion 15) of this embodiment is provided inside the screw to be screwed (without separating from the screw). Therefore, even if the cap is not strong due to the force of tilting with respect to the container opening, the engagement of the engaging portion will not be disengaged. Therefore, even if only one engaging portion is provided, it can be securely prevented from loosening. The conventional screw cap locking devices are usually provided at two positions facing each other at an angle of about 180 ° on the circumference of the cap inlet portion apart from the screw portion. In that case, in order to avoid the state where the lock is engaged before tightening is completed (before the cap rotation angle is 180 °), it is necessary to take measures such as using a coarse lead screw as a double thread screw. It was However, in the case of the present embodiment, such consideration is not required so much, and the degree of freedom in selecting the lead and pitch of the screw, the position and shape of the engaging portion, the number, and the like increases. Of course, in the same screw cap as in the present embodiment, it is also possible to adopt a multi-thread screw and provide each thread with a locking engagement portion.

FIG. 3 is a sectional view of the whole mold for injection molding the screw cap of this embodiment. The state that the core pin and the slide piece are in the mold cavity is shown. FIG. 4 shows a state in which the core pin and the slide piece are slightly pulled out from the cavity after injection molding in the mold of FIG.

In FIG. 3, the core pin 41 is inserted into the cavity 63 of the mold 61. At this time, the tip portion 53 of the slide piece 51 fills a part of the thread groove 43 formed on the outer surface of the core pin 41, and when the plastic material is injected from the injection hole 49 into the cavity 63, the slide piece The plastic does not flow into the screw groove 43 portion filled with the tip portion 53 of 51. Therefore, the inner thread 3 of the screw cap 31 is formed in the thread groove 43 other than the same portion, but it is not formed in the same portion, and the thread is notched.

In FIG. 4, first, the slide piece 51 is
The inside of the groove formed in the core pin 41 extends downward in the drawing. Therefore, the slide pin tip portion 53 has the core pin 41
To the outside (downward) of the thread groove 43. Further, the core pin 41 itself also protrudes slightly downward, and along with this, the injection-molded cap 31 also descends. From this point, when the core pin 41 is rotationally withdrawn in synchronization with the pitch of the thread groove 43, the thread groove 43 of the core pin 41 is pulled out downward while rotating along the thread of the screw cap. The lower surface of the cap 31 is a stripper plate 65.
Since the cap 31 is not in contact with the cap 31 and cannot go down, the core pin and the cap 31 are separated and the cap 31 can be taken out. At this time, the slide piece tip portion 53
Since the screw cap 31 retreats downward from the screw thread portion, it does not interfere with the screw cap 31 screw thread during the above-mentioned rotation extraction, and the screw cap 31 has an inner thread 7 in front of the notch portion (FIG. 1). A screw having a normal cross-sectional shape can also be obtained for the part. It is not necessary to positively stop the screw cap from rotating during the above-described core pin extracting operation. Therefore, the rotation stop ribs and the like at the lower end of the cap are unnecessary in the screw cap manufactured by this method.

5 to 8 are views showing a screw cap and a container mouth screw portion of a modified example of the present invention. Screw cap 1
One concave portion 71 is provided at the lower end of the cap.
The concave portion 71 has an engaging projection 73 at the base end of the container mouth screw portion,
Engages at the same time as the screwing is completed to prevent the screw from loosening. The screw cap of this embodiment can also be manufactured by the same mold and manufacturing method as those described above. Therefore, the screw portion and the loosening prevention portion can be integrally formed, and both can have desired shapes. In this example, it is not necessary to cut out the cap screw thread, and it is possible to accurately position the cap when it is necessary to align the cap and the bottle, such as a square outer shape of the cap.

In the screw cap of this embodiment,
The loosening prevention engagement portion is provided at a portion removed from the screw. However, according to the method of the present invention, the engaging portion can be provided near the screw. Therefore, the engagement is stable even when the above-mentioned force that tilts the cap is applied, so that only one engagement portion is required. Further, since the annular protrusion 75 of the container mouth is immediately below the engaging protrusion 73,
The annular protrusion 75 may contact the cap to prevent the cap from tilting more than a certain amount. Also, in the same screw cap as this embodiment, the screw is a multi-start screw,
For example, a double thread screw may be used. At that time, the concave portions 71 of the cap may be provided at two positions facing each other at an angle of 180 ° on the inner circumference of the cap. Further, at this time, it is not always necessary to provide the engaging protrusions 73 at the container mouth at two places.
When only one engaging projection 73 is provided, the lead of the screw may be selected so that the engaging projection 73 does not interfere with the recessed portion of the cap almost one rotation before the screwing of the cap is completed. Therefore, there is more room for selection of screw leads. This also applies to the other embodiments.

FIG. 9 is an assembled sectional view showing a screw cap with locking member and a container port to which the screw cap is attached according to another embodiment of the present invention. FIG. 10 is a cross-sectional view showing the AA cross section of FIG. 9. The screw cap of this embodiment is a plastic screw cap having a cap body having an inlet, and a first inner screw and a second inner screw provided on the inner surface of the cap body. The inner screw has a larger diameter than the first inner screw, and is provided closer to the inlet side of the cap than the first inner screw.
And the second inner screw thread has a molding die core pin having a thread groove of a shape corresponding to this on the outer surface, and after injecting plastic into the thread groove, the core pin is rotationally extracted. The second inner screw thread has a notch portion cut out at a portion within one lap from the inlet side starting end of the screw thread, and the notched portion is a container to which the cap fits. It is characterized in that it can be used as a loosening stopper for a screw by engaging with a coupling protrusion provided on the mouth.

The screw cap main body 82 has a cylindrical shape with a top, and has an inlet 90 into which a container mouth is inserted on the lower surface. The inner surface of the cap main body 82 is composed of three surfaces of an inlet side inner surface 101, a center inner surface 103, and a rear side inner surface 105 from the inlet 90 side to the inner side (from bottom to top in FIG. 9). Entrance side inner surface 10
1 has the largest diameter of the three surfaces, and the second inner thread 93 is provided on this surface. The center inner surface 103 has a smaller diameter than the inner surface 101 on the inlet side, and the first inner thread 83 is provided on this surface. The inner surface 105 on the back side is located at the innermost side of the inner surface of the cap and has a smaller diameter than the inner surface 103 of the center.

The first inner thread 83 is screwed with the outer thread 113 on the outer surface of the container opening 111, and the screw cap 81 is attached to the container opening 111. The starting end 84 of the first inner thread is tapered to facilitate engagement with the outer thread starting end on the container side.

The second inner thread 93 is the first inner thread 83
Is provided closer to the inlet 90 side of the cap. The diameter of the second inner thread 93 is larger than the diameter of the first inner thread 83. In this embodiment, the diameter of the top of the second inner thread 93 is equal to the diameter of the trough of the first inner thread 83 (the former may be larger than the latter). Therefore, the outer thread 1 of the container mouth
13 does not interfere with the second inner thread 93 at all after being screwed into the first inner thread 83. Further, the lead of the first inner thread 93 and the lead of the second inner thread 83 are equal.

The second inner thread 93 has a notch portion 95 which is notched in a portion within one round from the inlet-side starting end 99 of this thread. The notch 95 has a container opening 1
The engaging projection 115 protruding from the base of 11 is fitted,
It plays the role of preventing screws from loosening. The second inner screw 93 does not need to be screwed with the outer screw on the container port 111 side.

As shown in FIG. 10, when the cap screwing is completed, the engaging protrusion 115 of the container opening 111 is formed.
Fits in the notch 95 of the second inner thread 93 of the cap. Engaging projection end 114 of the engaging projection 115
Abuts the rear thread crest end 94 of the notch 95 to prevent overrun of the screw. The front side engagement protrusion end 116 of the engagement protrusion 115 abuts on the front side thread ridge cutout end portion 96 of the cutout portion 95 to prevent loosening of the screw.

The cross section of the inner thread 97 before the notch 95 has the same width but a lower height than the cross section of the second inner thread 93 of the other portion. Container mouth 1
This is to prevent excessive interference from occurring when the engaging projection 115 on the 11 side passes through the inner thread 97 of this portion. The widths are the same in order to prevent sagging and wear of the inner thread 97 of this portion. The width of the second inner thread 93 itself is larger than the width of the first inner thread 93 for the same reason. Also, the entry-side thread starting end 99 of the second inner thread is not tapered. This is because it is not necessary to consider guiding the mating screw to be screwed.

In the screw cap of this embodiment, the first inner screw thread 83 screwed into the outer screw of the container opening and the second inner screw thread 93 having the notch 95 for locking are provided separately. With screws. Therefore, the first inner thread 83
Does not come into contact with the engaging projection 115 of the container port 111, so that the thread start end (cutting start) is not worn or deformed (crushed) even with high frequency use. Therefore, the smooth tapered shape of the same portion is not impaired, and the smooth start of screwing with the male screw can be maintained forever.

Further, since the second inner thread does not screw with the outer thread of the container opening, the thread width of the starting end (cutting start) can be widened. Therefore, the engagement (the overrun prevention and the loosening prevention) with the engagement protrusion of the container opening is stable. It should be noted that the first inner thread and the second inner thread are both single-start threads in this embodiment, but it is clear that they may be multi-start threads.

Furthermore, when a glass bottle or the like is used for the container body, the glass mold can be made inexpensive because the engaging protrusion on the bottle side is at the bottle mouth. This is because the mold for the glass bottle is a separate mold for the body of the bottle and the mouth of the bottle (the portion where the external screw is cut), but the mold for the mouth of the bottle is better. Since it is smaller than the mold of the main body, the price is usually less than one tenth. Since the mold part that molds the corners of the engaging projections is generally easily worn, the life of the mold is short, but when replacing the mold, it is sufficient to replace the mold at the cheap bottle mouth. The overall mold cost is low. Needless to say, the container body that is the counterpart of the screw cap of the present invention is not limited to the glass bottle.
Naturally, a plastic container (blow-molded product or the like) may also be used.

In the embodiment of FIG. 9, a seat packing 121 is attached to the inner surface 105 on the back side of the cap.
Since the seat packing 121 is hooked on the protrusion 87 provided on the inner surface 105 of the back side, the seat packing 121 is removed even when the screw cap 81 is removed from the container port 111.
Never falls from the cap. Seat packing 1
21 is the inner surface of the top portion 85 of the cap and the upper end surface 1 of the container opening.
The liquid and volatile components in the container are prevented from leaking out by being compressed and held between them.

In FIG. 9, an annular step 117 provided at the base of the container opening 111 is an internal thread on the inner surface of the cap 81 when the screwed cap is twisted obliquely with respect to the container. By contacting the top of 93, the cap is prevented from rattling. The second inner screw having the locking engagement portion is usually provided immediately below the first inner screw. Therefore, even if the cap is slightly loosened (even if it is tilted with respect to the container mouth), the engaging portion does not come off, so that there is no problem even if the engaging portion is located at one place on the circumference.

[0039]

As is apparent from the above description, the screw cap with lock and the manufacturing method thereof according to the present invention have the following effects. It is possible to obtain a screw cap having both a sharp and high-profile screw thread, which is a feature of the core pin rotation extraction method, and a screw thread notch that can be used in a highly reliable locking mechanism. A screw cap that can be firmly tightened and that will not loosen even if affected by vibration or the adhesion of contents is obtained.

A screw cap suitable for cosmetics and chemicals having high volatility and lubricity can be obtained. The above-mentioned screw cap having high performance can be manufactured with good productivity and at low cost. Since the rotation stop rib is not formed at the lower end, it has an excellent appearance and the thickness of the cap itself can be reduced. Since the screw portion and the locking portion can be integrally formed, the manufacturing and assembling costs can be reduced as compared with the conventional method in which both portions are separately formed and assembled.

[Brief description of drawings]

FIG. 1 is a sectional view showing a screw cap for a nail varnish container according to an embodiment of the present invention.

FIG. 2 is a partial sectional front view of a container port into which the screw cap of FIG. 1 is screwed.

FIG. 3 is a cross-sectional view of the injection molding die of the screw cap of the present embodiment. The state that the core pin and the slide piece are in the mold cavity is shown.

FIG. 4 shows a state in which the core pin and the slide piece are slightly pulled out from the cavity after injection molding in the mold of FIG.

FIG. 5 is a sectional view showing a screw cap according to another embodiment of the present invention.

6 is a bottom view showing the lower end surface of the screw cap of FIG.

7 is a perspective view showing the screw cap of FIG. 5. FIG.

8 is a front view of a container port into which the screw cap of FIG. 5 is screwed.

FIG. 9 is an assembly cross-sectional view showing a screw cap with locking member and a container port to which the screw cap is attached according to another embodiment of the present invention.

10 is a cross-sectional view showing a cross section taken along the line AA in FIG.

[Explanation of symbols]

1: Screw cap 81: Screw cap 2: Cap main body 82: Cap main body 3: Inner screw thread 83: First inner screw thread 4: Back side screw thread notched end portion 84: First inner screw thread starting end 5: Off Notch 85: Top 6: Front side screw thread notched end 87: Protrusion 7: Notch section front inner screw thread 90: Inlet 9: Inlet side screw thread start end 93: Second inner screw thread 10: Inlet 94: Back side thread notch end 11: Container mouth 95: Notch 13: Outer thread 96: Front side thread notch end 14: Back side engaging protrusion end 97: Notch front inner thread 15 : Engagement protrusion 99: Entrance side screw thread start end 16: Front side engagement protrusion end 101: Inlet side inner inner surface 17: Outer thread groove 103: Central inner surface 31: Screw cap 105: Back inner surface 41: Core pin 106: Step portion 43: Core pin screw groove 111: Container port 49: Injection 113: Outer screw thread 51: Slide piece 114: Inner side engaging protrusion end 53: Top end portion 115: Engaging protrusion 61: Mold 116: Front side engaging protrusion end 63: Cavity 117: Annular step 65: Stripper plate 119: Upper end surface of container port 71: Cap recess 121: Seat packing 73: Engagement protrusion

Claims (12)

[Claims] 1. A plastic screw cap comprising a cap body having an inlet and an inner screw provided on an inner surface of the cap body, wherein the screw thread of the inner screw has a shape corresponding to the screw thread. Using a mold die core pin that has a groove on the outer surface, it is molded by a method of injecting plastic into this thread groove and then extracting this core pin by rotation, and the inner thread is from the inlet side start end of this thread It has a notch part that is notched within one turn, and this notch part can be used as a screw loosening stopper by engaging with a coupling protrusion provided on the container mouth where the cap fits. A screw cap with a locking device that is characterized in that 2. A plastic screw cap having a cap body having an inlet, and a first inner screw and a second inner screw provided on an inner surface of the cap body, wherein the second inner screw is provided. Is larger than the first internal thread,
In addition, a molding die core pin is provided which is provided closer to the inlet side of the cap than the first inner screw, and in which the screw threads of the first and second inner screws have a thread groove of a shape corresponding to the screw thread on the outer surface. Used,
The core pin is molded by rotating the core pin after the plastic is injected into the thread groove, and the second inner thread is notched at a portion within one lap from the inlet end of the thread. A lock screw having a notch portion, which can be used as a lock stopper for a screw by engaging the coupling protrusion provided at the container mouth where the cap is fitted with the notch portion. cap. 3. The cutout portion fills a part of the thread groove with a slide piece provided slidably in an axial direction of the core pin in a portion including a part of the outer surface of the core pin, and a plastic material is provided to the portion. The screw cap with a locking device according to claim 1 or 2, wherein the screw cap is cut out by blocking an inflow. 4. The screw thread of the inner screw on the inlet start end side from the cutout portion is a complete screw thread having substantially the same cross-sectional shape as the screw threads of the inner screw of the other portion. Screw cap with lock. 5. The screw thread of the second inner screw on the inlet start end side from the cutout portion is a complete screw thread having substantially the same cross-sectional shape as the screw threads of the second inner screw of the other portion. Item 2 or 3
Screw cap with lock as described. 6. The screw cap with locking device according to claim 1 or 3, wherein the cross section of the thread from the cutout portion on the inlet start end side is narrower or lower than the cross section of the thread of the other portion. 7. The cross section of the thread of the second inner screw on the inlet start end side from the notch is narrower or lower than the cross section of the thread of the second inner screw in the other portion. Alternatively, the screw cap with a locking member according to 3 above. 8. The screw cap with a locking member according to claim 1, wherein the cutout portion is cut out from a root of a screw thread. 9. The screw cap with a locking member according to claim 1, wherein the plastic is a hard plastic. 10. The lock screw according to any one of claims 1 to 9, wherein the end face on the inlet side of the screw cap does not have a rotation stopping engagement portion for stopping the rotation of the screw cap when the core pin is rotationally pulled out. cap. 11. A screw cap formed by injection molding, wherein a thread is formed by a method of rotating and extracting a mold core pin after molding, and at least one recess or protrusion is formed from a lower end of the cap. A screw cap with a locking device, characterized in that, at the same time when the screw-fitting with the container is completed, the locking portion projection or dent of the container is engaged with the cap recess or projection. 12. A mold comprising: a core pin having an outer peripheral surface with a thread groove and a slide piece capable of advancing in the axial direction of the core pin so as to fill a part of the thread groove; Characterized by injecting plastic into the cavity of the mold with a part of the thread groove filled in, then withdrawing the slide piece out of the thread groove, and then withdrawing the core pin by rotation. The method for manufacturing a screw cap with a locking device according to claim 1 or 2.